PACKAGING APPLIANCE, USE OF SUCH APPLIANCE AND PROCESS OF PACKAGING A PRODUCT DISPOSED ON A SUPPORT

专利摘要:
this is a process for packaging a product (p) arranged on a support (4) which comprises unrolling a film (18), moving the film (18) to a packaging assembly (8) which defines a chamber inside it. of packaging (24), which progressively move numerous supports (4) inside the packaging chamber (24) of the packaging assembly (8), close the packaging chamber (24) with the film sheets held above the respective support (4 ), which optionally causes one or both of: a removal of gas from the hermetically closed packaging chamber (24) and a gas injection of a gas mixture of controlled composition, heat sealing the film (18) to said support (4 ), where the heat seal uses one or more heaters that have heating surfaces that are heated only for distinct and short periods of time. an apparatus (1) for carrying out the above process is also disclosed.
公开号:BR112017007124B1
申请号:R112017007124-0
申请日:2015-10-08
公开日:2021-08-24
发明作者:Jvanohe Rizzi；Sergio Chiodini；Stefano Capitani
申请人:Cryovac, Inc；
IPC主号:

专利说明:

TECHNICAL FIELD DESCRIPTION
[001] The present invention relates to an apparatus and a process for packaging a product. According to certain aspects, the invention relates to an apparatus and process for packaging a product under a controlled atmosphere or under vacuum. According to other aspects the invention relates to an apparatus and method for film packaging a product. In particular, the apparatus and method according to the invention adopt an innovative heater for the heat sealing of plastic films. TECHNICAL BACKGROUND
[002] Plastic containers are commonly used for food packaging and for a wide variety of other items where a plastic film forming a film or lid is attached to the container, for example, by applying heat, or where a plastic film is wrapped around the item or items to be packaged and then heat sealed.
[003] One method of attaching the lid to the tray involves the use of a laminated plastic lid that has a sheet metal layer: a power supply supplies an electrical current to a nearby induction coil that induces an electrical current in the foil. metal to develop heat which melts portions of the lid and container and melts the lid onto the container edge. For example, patent document no EP0469296 discloses an induction sealing assembly which uses a single turn coil to seal an edge of plastic to a plastic container. The assembly includes a housing having a recess for retaining a container to be sealed, and a movable sealing head for retaining a lid or foil membrane and for positioning the lid relative to an opening in the container. Means are provided for securing a portion of the sealing head against a portion of the housing to form a hermetic chamber between a lower portion of the sealing head and an upper portion of the housing. The induction seal assembly uses a vacuum source and an inert gas source to expel air from the container before sealing. An induction coil mounted on the sealing head induces an electrical heating current in the lid to seal the lid to the container.
[004] In order to package products, in particular food products, vacuum packages have been developed in the past.
[005] Among the known vacuum packaging processes, vacuum film packaging is commonly employed to package food products such as fresh and frozen meat and fish, cheese, processed meat, ready meals and the like. Vacuum film packaging is described, for example, in patent documents FR 1 258 357, FR 1 286 018, AU 3 491 504, US RE 30 009, US 3 574 642, US 3 681 092, US 3,713,849, US 4,055,672 and US 5,346,735.
[006] Vacuum film packaging is basically a thermoforming process. In particular, the product is typically placed on a rigid or semi-rigid support (such as a tray, pot or cup). The support with the product placed on it is placed in a vacuum chamber, in which a film of thermoplastic material, held in a vacuum in a position above the product placed on the support, is heated to soften it. The space between the backing and the film is then evacuated and finally the vacuum over the film is released to cause the film to drape down around the entire product and seal to the backing surface not covered by the product, thus forming a firm film around the product and on the backing.
[007] Patent document in US 2007/0022717 discloses a machine for gas-leak-proof packaging of an object with the use of a film material. The machine has a lower tool to support two trays and an upper tool that has cutting devices housed inside the upper tool and facing the lower tool. A film is sandwiched between the top tool and the bottom tool. The upper and lower tools are first closed against each other and then the film is cut to the size of the peripheral edges of the trays through the cutters operative within the upper tool. The sealing tools heat seal the cut regions of the film to the peripheral edge of the tray. A vacuum is placed in the region around the tray to cause deep stamping of the film. This reference also mentions that the same device can be used to seal trays with films that are not subjected to deep drawing in order to form a film on the product.
[008] Patent document US 2005/0257501 discloses a machine for packaging a product arranged in a tray. The machine has a lower tool to support the tray and an upper tool with a cutting device. During operation, the film is pinched along an edge surrounding the tray and is deformed by the top tool in a direction that extends away from the product. The space surrounding the product is then evacuated, the film and tray edge are sealed and the film is then cut by the cutting device.
[009] Patent document no WO2011/012652 shows an apparatus for packaging a product in a tray. The machine comprises a first film transfer plate configured to hold a sheet of film, heat the sheet of film, bring the sheet of film to a position above a tray with the product disposed thereon, and hermetically secure the sheet. of film to the tray. A second film transfer plate is also present. As for the first film transfer plate, the second film transfer plate is also configured to hold a film sheet, heat the film sheet, bring the film sheet to a position above a tray with the product disposed on the and securely attach the film sheet to the tray. During a first stage of machine operation, the first film transfer plate retains a first film sheet and heats the first film sheet, while the second film transfer plate releases a second film sheet and thereby allows the second sheet is dragged into a first tray; and during a second operating stage of the machine, the second film transfer plate retains a third film sheet and heats the third film sheet, while the first film transfer plate releases the first film sheet and thereby allows the first sheet of film is dragged into a second tray. The machine further comprises a rotating cylinder suitable for rotating about its geometric axis X, wherein the first film transfer plate and the second film transfer plate are connected to the rotating cylinder so that when the rotating cylinder rotates about its axis geometric X, the positions of the first film transfer plate and the second film transfer plate are swapped. A vacuum arrangement allows air to be removed from the tray below the film sheet (positioned either by the first or second film transfer plate) through at least one hole present in the tray. Film transfer plates are configured to release the film sheet and thereby allow the film sheet to be dragged into the tray while the vacuum arrangement removes air from the tray.
[0010] Patent document in WO8500339 discloses a packaging apparatus in which a tray is housed in a lower tool holder and wherein the upper tool comprises a heating head, which is in a single heated body. The heating head has a peripheral projecting portion which acts on a peripheral band of a film portion of a film to heat seal said peripheral portion to a corresponding horizontal edge of the tray. A central portion of the heating head is covered with an insulating material in the form of a plate. Sealing can be accomplished by means of an impulse sealing technique or through other sealing techniques.
[0011] Patent document no GB958602 shows a packaging apparatus having a pulse heating system for heating a peripheral heater which acts on a peripheral strip of film to heat seal the latter.
[0012] Although at least some of the solutions described above have been adopted with satisfaction, there remains a need to further improve the control of plastic film heating during a heat seal.
[0013] Thus, it is an object of the invention to make available a process and an apparatus for the heat sealing portions of a plastic film, for example, for a support that hosts a product or for other plastic films or other film portions, in that at least during one heat sealing phase the control of heat fed to the active heating surfaces in the film is improved.
[0014] It is a further objective to design a process and apparatus capable of reducing energy consumption while efficiently providing the heat required for a heat seal.
[0015] Additionally it is an object of the invention to provide an apparatus and a process in which heat sealing can take place efficiently even with thermosensitive films, such as heat shrinkable films.
[0016] It is an auxiliary objective of the invention to devise a process and an apparatus that can operate both for a film packaging and for a modified atmosphere packaging. SUMMARY OF THE INVENTION
[0017] One or more of the objectives specified above are substantially achieved through a process and through an apparatus according to any of the appended claims.
[0018] Aspects of the invention are disclosed below in the present document.
[0019] A 1st aspect concerns a packaging device comprising:
[0020] a packaging assembly configured to receive at least one support and to securely attach a film to the support,
[0021] and the packaging assembly includes:
[0022] - a lower tool that defines a predetermined amount of supports configured to receive said at least one support with a product to be packaged,
[0023] - an upper tool facing the lower tool and cooperating with it,
[0024] wherein said upper tool and lower tool are relatively mobile at least between a first operating condition, wherein the upper tool and lower tool are spaced apart and allows the positioning of at least a portion of the film of the said film above one or more of said at least one support, and a second operating condition, in which the upper tool and the lower tool are brought closer together and allows a heat sealing of said portion of film to the hair. minus one support located on said one or more supports,
[0025] - an internal heater carried by the upper tool having a heating surface configured to heat at least a part of said portion of film,
[0026] - a peripheral heater carried by the upper tool and positioned radially outwardly with respect to the internal heater, the peripheral heater having a heating surface configured to heat seal the at least one support at least one peripheral region of said film portion;
[0027] a supply unit configured to control an energy supplied to said peripheral heater and to said internal heater; and
[0028] a control device that acts on the supply unit and is configured to command the supply unit and control a power supply for the peripheral heater independently of a power supply for the internal heater.
[0029] In a 2nd aspect according to the 1st aspect, said control device is additionally configured to command the supply unit to perform a heating cycle that includes the following steps:
[0030] increase a peripheral heater heating surface temperature to a first temperature, maintain the peripheral heater heating surface at least at the first temperature for a first distinct time interval, reduce the temperature of the peripheral heater heating surface below the said first temperature,
[0031] increase a temperature of the heating surface of the internal heater to a second temperature, maintain the heating surface of the internal heater at least at the second temperature for a second distinct time interval, reduce the temperature of the heating surface of the internal heater below the said second temperature.
[0032] In a 3rd aspect according to the previous aspect the first temperature is different from the second temperature.
[0033] In a 4th aspect according to either of the two previous aspects, said control device is further configured to command the supply unit to consecutively repeat the execution of said heating cycle a plurality of times, during each of said consecutive heating cycles at least one of said film portions is heat sealed on at least one respective support. In practice, the heating cycle starts when the hot bonding operation starts (for example, after the peripheral heating surface touches the film and the peripheral region of the film portion is in contact with a corresponding surface of the support - for example , in the case of a tray when the peripheral region or boundary of the film portion contacts the top surface of the tray top edge) and ends as soon as (or even just before) the heating surface of the heater peripheral is lifted from the film.
[0034] In a 5th aspect according to any of the three previous aspects wherein said control device is configured to control the supply unit in such a way that - during each heating cycle - the supply unit supplies energy to the peripheral heater only for a distinct period of time followed by a period of time when no power is supplied to the peripheral heater to cause rise and maintain the heating surface of the peripheral heater at least at the first temperature for the first distinct time interval, and to cause a subsequent reduction in the temperature of the heating surface of the peripheral heater below said first temperature.
[0035] In a 6th aspect according to any one of the four foregoing aspects wherein said control device is configured to control the supply unit in such a way that - during each heating cycle - the supply unit supplies energy to the internal heater only for a distinct period of time followed by a period of time when no power is supplied to the internal heater to cause rise and maintain the heating surface of the internal heater at least at the second temperature for the second distinct time interval, and to cause a subsequent reduction in the temperature of the heating surface of the internal heater below said second temperature.
[0036] In a 7th aspect according to any one of the previous five aspects in which the heating cycle is configured in such a way that the second temperature is lower in relation to the first temperature.
[0037] In an 8th aspect according to any one of the preceding six aspects wherein said first temperature is comprised between 150°C and 300°C.
[0038] In a 9th aspect according to any one of the preceding seven aspects wherein said first temperature is comprised between 180 to 240°C.
[0039] In a 10th aspect according to any one of the eight foregoing aspects wherein said first temperature is comprised between 200 to 220°C.
[0040] In an 11th aspect according to any one of the nine foregoing aspects wherein said second temperature is comprised between 150°C and 300°C.
[0041] In a 12th aspect according to any one of the preceding tenaspects wherein said second temperature is comprised between 180 to 240°C.
[0042] In a 13th aspect according to any one of the eleven foregoing aspects wherein said second temperature is comprised between 200 to 220°C.
[0043] In a 14th aspect according to any one of the preceding twelve aspects the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds.
[0044] In a 15th aspect according to any one of the thirteen foregoing aspects the second distinct time period has a duration comprised between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds.
[0045] In the 16th aspect according to any one of the previous fourteen aspects in which the control device is configured to command the supply unit to sharply increase the temperature of the heating surface of the peripheral heater from a respective reference temperature to the first temperature. To increase sharply means to increase said temperature of the heating surface of the peripheral heater with a rate of temperature increase with time greater than 1°C/ms, optionally greater than 5°C/ms.
[0046] In a 17th aspect according to any of the previous fifteen aspects in which the control device is configured to command the supply unit to sharply increase the temperature of the heating surface of the internal heater from a respective reference temperature to the second temperature. To increase sharply means to increase said temperature of the heating surface of the internal heater with a rate of temperature increase with time greater than 1°C/ms, optionally greater than 5°C/ms.
[0047] In an 18th aspect according to any of the sixteen aspects above in which each heating cycle is configured in such a way that the increase in the temperature of the heating surface of the internal heater to a second temperature starts after the increase in the temperature of the peripheral heater to the first temperature, the start of said second distinct time interval being delayed relative to the start of said first time interval.
[0048] In a 19th aspect according to any one of the previous seventeen aspects wherein the duration of said first distinct time interval is greater than the duration of said second distinct time interval.
[0049] In a 20th aspect in accordance with any of the foregoing aspects in which:
[0050] - the heating surface of said peripheral heater has an annular shape and surrounds the heating surface of the internal heater, and
[0051] - when the upper and lower tools are in said second operating position, the peripheral heater is configured to heat a peripheral band (in other words the peripheral region is in the form of a peripheral band) of said film portion while the heater inner is configured to heat at least a part of an inner zone of the same film portion located radially within the peripheral band.
[0052] In a 21st aspect according to any of the foregoing aspects in which both the heating surface of the peripheral heater and the heating surface of the internal heater are flat.
[0053] In a 22nd aspect according to any of the foregoing aspects wherein at least when the upper and lower tools are in said second operating position, the heating surface of the internal heater is coplanar to the heating surface of the peripheral heater or indented with respect to the heating surface of the peripheral heater in such a way that when the heating surface of the peripheral heater is in contact with the top surface of the film portion, the heating surface of the internal heater is offset by a preset distance from the surface top of the same portion of film. In particular, the indentation can be a slight indentation of the order of a few mm (1 to 10 mm).
[0054] In a 23rd aspect in accordance with any of the foregoing aspects in which:
[0055] the heating surface of the internal heater is located at a radial distance from the heating surface of the peripheral heater and extends in an area surrounded by the heating surface of the peripheral heater.
[0056] In a 24th aspect according to any of the foregoing aspects wherein said heating surface of the internal heater is an annular shaped heating surface,
[0057] or a continuous heating surface delimited by a single closed contour line, optionally a discoidal or polygonal continuous heating surface, wherein the continuous heating surface occupies substantially all or a majority of said area surrounded by the heating surface of the heater peripheral,
[0058] or a heating surface that includes a plurality of spaced parallel strips connected at their ends by the connecting portions.
[0059] In a 25th aspect according to any of the foregoing aspects the peripheral heater comprises a first electrically conductive element that extends along the heating surface of the peripheral heater., for example, the peripheral heater may be entirely formed by the first electrically conductive element.
[0060] In a 26th aspect according to the previous aspect in which said first electrically conductive element is an electrically conductive annular element.
[0061] In a 27th aspect according to the previous aspect in which the first electrically conductive element is an electrically conductive annular flat element.
[0062] In a 28th aspect according to any of the foregoing aspects the internal heater comprises a second electrically conductive element which extends along the heating surface of the internal heater., for example, the internal heater may be entirely formed by the second electrically conductive element.
[0063] In a 29th aspect according to the previous aspect the said second conductive element is an electrically conductive annular element, optionally an electrically conductive annular flat element.
[0064] In a 30th aspect according to the 28th aspect the said second conductive element is a continuous electrically conductive plate.
[0065] In a first 31st according to the 28th aspect said second conductive element is an electrically conductive meander element, optionally an electrically conductive flat meander element. By meander element is meant a bar-shaped conductor (optionally flat bar-shaped) which forms a winding comprising adjacent parallel members transversely connected to ends thereof.
[0066] In a 32nd aspect according to any of the foregoing aspects the first electrically conductive element comprises:
[0067] - a support substrate carried by the top tool,
[0068] - a metallic conductive strip fixed to the supporting substrate, and
[0069] - an optional protective layer covering the conductive metal strip and defining the heating surface of the peripheral heater.
[0070] In a 33rd aspect according to any of the previous aspects from the 1st to the 31st the first electrically conductive element comprises:
[0071] - a support substrate loaded by the top tool,
[0072] - an insulation layer in contact with the supporting substrate,
[0073] - a conductive layer in the form of a metal-glass mixture in contact with the insulating layer, and
[0074] - a protective layer covering the conductive layer and defining the heating surface.
[0075] In a 34th aspect according to any of the foregoing aspects 1st to 31st the first electrically conductive element comprises an electrically conductive carbon structure; the electrically conductive carbon structure includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[0076] a graphite structure,
[0077] a single-layer or multi-layer graphene structure,
[0078] a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[0079] It should be noted that the first electrically conductive element may be formed of an electrically conductive carbon structure completely formed in one or more of the carbon allotropes disclosed above.
[0080] For example, the first electrically conductive element may be exclusively formed from graphite, or the first electrically conductive element may be exclusively formed from a single layer of graphene, or the first electrically conductive element may be exclusively formed from a plurality of layers of mutually overlapping graphene, or the first electrically conductive element can be uniquely formed into a carbon nanotube fullerene structure, or the first electrically conductive element can be formed into a carbon nanofiber fullerene structure.
[0081] According to a further variant the carbon structure may comprise a structure formed by carbon filaments that are in contact adjacent to each other in order to form a conductive body or by carbon filaments embedded in a resin matrix of Plastic: In the latter case the carbon filaments can be placed adjacently and electrically connected to each other in prescribed sections such as at their ends.
[0082] In a 35th aspect according to the previous aspect in which the first electrically conductive element comprises a structural substrate carrying said carbon structure and at least one protective layer covering the carbon structure on an opposite side to it of the structural substrate. In one embodiment said carbon structure is sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said peripheral heater; for example, the carbon structure of the first electrically conductive element comprising a plurality of mutually overlapping graphene layers that form a flat (optionally elongated) shaped carbon structure.
[0083] In a 36th aspect according to either of the two foregoing aspects wherein the carbon structure of the first electrically conductive element of the peripheral heater has a cross section having a thickness of at least 5 μm and a width of at least 2mm, plus optionally a cross section with a thickness of at least 10 µm and a width of at least 5 mm., for example, the carbon structure of the first electrically conductive element of the peripheral heater can have a cross section thickness between 5 and 300 µm, optionally between 10 and 200. The cross-sectional width may be at least 2 mm, more optionally at least 5 mm.
[0084] In a 37th aspect according to any of the three previous aspects in which the carbon structure of the first electrically conductive element of the peripheral heater has an average electrical resistivity greater than 5 Q «mm2/m, which is optionally comprised between 15 and 25 mm 2 /m.
[0085] In a 38th aspect according to any of the foregoing aspects the second electrically conductive element comprises:
[0086] - a support substrate loaded by the top tool,
[0087] - a conductive metallic structure selected from the group of: a strip, a plate and a meander, said conductive metallic structure being fixed to the supporting substrate, and
[0088] - an optional protective layer covering the metallic conductive structure and defining the heating surface of the peripheral heater.
[0089] In a 39th aspect according to any of the previous aspects 1st to 37th the second electrically conductive element comprises:
[0090] - a support substrate loaded by the top tool,
[0091] - an insulation layer in contact with the supporting substrate,
[0092] - a conductive structure in the form of a metal-glass mixing layer that takes the form of a strip, a plate or a meander, said conductive structure being in contact with the insulating layer, and
[0093] - a protective layer covering the conductive layer and defining the heating surface.
[0094] In a 40th aspect according to any of the foregoing aspects 1st to 37th the second electrically conductive element (for example, in the form of a meand or plate or flat annular shaped element) comprises an electrically carbon structure conductive; the electrically conductive carbon structure includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[0095] a graphite structure,
[0096] a single-layer or multi-layer graphene structure,
[0097] a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[0098] It should be noted that the second electrically conductive element may be formed of an electrically conductive carbon structure completely formed in one or more of the carbon allotropes disclosed above.
[0099] For example, the second electrically conductive element may be exclusively formed from graphite, or the second electrically conductive element may be exclusively formed from a single layer of graphene, or the second electrically conductive element may be exclusively formed from a plurality of layers of mutually overlapping graphene, or the second electrically conductive element can be uniquely formed into a carbon nanotube fullerene structure, or the second electrically conductive element can be formed into a carbon nanofiber fullerene structure.
[00100] According to a further variant the carbon structure may comprise a structure formed by carbon filaments that are in contact adjacent to each other in order to form a conductive body or by carbon filaments embedded in a resin matrix Plastic: In the latter case the carbon filaments can be placed adjacently and electrically connected to each other in prescribed sections such as at their ends.
[00101] In a 41st aspect according to any of the foregoing aspects 1st to 37th the second electrically conductive element comprises a continuous electrically conductive flat element, such as a strip or a plate; for example, the electrically conductive carbon structure of the second electrically conductive element may comprise one or more layers of graphene.
[00102] In a 42nd aspect according to any of the foregoing aspects 1st to 37th the second electrically conductive element comprises an electrically conductive meander element, optionally an electrically conductive flat meander element; for example, the electrically conductive carbon structure of the second electrically conductive element may comprise one or more layers of graphene.
[00103] In a 43rd aspect according to any of the three aspects above the second electrically conductive element comprises a structural substrate carrying the respective carbon structure and at least one protective layer covering the carbon structure on an opposite side to the even of the structural substrate, optionally wherein said carbon structure is sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said internal heater; for example, the electrically conductive carbon structure of the second electrically conductive element may comprise one or more layers of graphene.
[00104] In a 44th aspect according to any of the four foregoing aspects the carbon structure of the second electrically conductive element of the internal heater has a cross section having a thickness of at least 5 μm and a width of at least 5 mm, plus optionally a cross section with a thickness of at least 10 µm and a width of at least 10 mm.
[00105] In a 45th aspect according to any of the previous five aspects the carbon structure of the second electrically conductive element of the internal heater has an average electrical resistivity greater than 2Q^mm2/m, optionally greater than 2Q^mm2 /m
[00106] In a 46th aspect according to any of the foregoing aspects the apparatus includes a cooling circuit associated with the upper tool and configured to cool said internal heater and said peripheral heater, the cooling circuit being controlled by the control device which is further configured to cause circulation of a coolant in said cooling circuit and to regulate a coolant temperature. The control device can set the coolant at a temperature well below the first and second temperature, for example, greater than 100°C below said temperatures.
[00107] In a 47th aspect according to any of the foregoing aspects the supply unit is an electrical source unit and comprises:
[00108] - at least one impulse transformer,
[00109] - at least one set of electrical circuits connecting the impulse transformer to the first electrically conductive element and to the second electrically conductive element.
[00110] In a 48th aspect according to any of the foregoing aspects the supply unit is an electrical source unit and comprises:
[00111] - at least a first pulse transformer and a first set of electrical circuits connecting the first pulse transformer to the first electrically conductive element, and
[00112] - at least one second pulse transformer and a second set of electrical circuits connecting the second pulse transformer to the second electrical impedance,
[00113] wherein said control device is configured to act on the electrical source unit to independently supply an electrical current at a predetermined voltage to said first and, respectively, second electrically conductive element.
[00114] In a 49th aspect according to any of the foregoing aspects the device comprises:
[00115] - a first temperature sensor configured to detect a temperature of the heating surface of the peripheral heater and output a corresponding first temperature signal correlated to the detected temperature. Note that the first temperature sensor can be a contact temperature sensor or a non-contact temperature sensor (eg an IR sensor). Also note that the presence of the first temperature sensor may not be necessary and the temperature of the heating surface can be calculated based on the measured electrical resistance of the first electrically conductive element.
[00116] For example, a first electrical sensor can be used, electrically connected or connectable to the carbon structure of the peripheral heater and configured to detect an electrical parameter of said carbon structure and emit a corresponding electrical parameter signal, where the parameter electric comprises one of:
[00117] an electrical impedance of a prefixed segment of said carbon structure,
[00118] an electrical current flowing through said prefixed segment of carbon structure when a prefixed electrical voltage is applied at ends of said prefixed segment,
[00119] an electrical voltage detected at the ends of the prefixed segment when a prefixed electrical current is imposed to flow through said prefixed segment.
[00120] In a 50th aspect according to any of the previous aspects the device comprises:
[00121] a second temperature sensor for detecting a temperature of the heating surface of the internal heater and outputting a second corresponding temperature signal correlated to the detected temperature. Note that the second temperature sensor can be a contact temperature sensor or a non-contact temperature sensor (eg an IR sensor). Also note that the presence of the second temperature sensor may not be necessary and the temperature of the heating surface can be calculated based on the measured electrical resistance of the second electrically conductive element.
[00122] For example, a second electrical sensor can be used, electrically connected or connectable to the carbon structure of the internal heater and configured to detect an electrical parameter of said carbon structure and emit a corresponding electrical parameter signal, where the parameter electric comprises one of:
[00123] an electrical impedance of a prefixed segment of said carbon structure,
[00124] an electrical current flowing through said prefixed segment of carbon structure when a prefixed electrical voltage is applied at ends of said prefixed segment,
[00125] an electrical voltage detected at the ends of the prefixed segment when a prefixed electrical current is imposed to flow through said prefixed segment.
[00126] In a 51st aspect according to either of the two previous aspects in which the control device is connected to said first temperature sensor and is configured to:
[00127] - receiving said first temperature signal and controlling the supply unit in order to supply power to the peripheral heater based on said first temperature signal and a desired value for said first temperature.
[00128] Alternatively the control device is connected to said first electrical sensor, and is configured to:
[00129] - receive said electrical parameter signal and control the supply unit in order to supply electrical energy to the electrically conductive element of the peripheral heater, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of the said voltage, based on said electrical parameter signal and a desired value for a heater heating surface temperature.
[00130] Note that the control device can also be configured to receive said electrical parameter signal and calculate an actual temperature value of the peripheral heater carbon frame based on:
[00131] a value of said electrical parameter and
[00132] a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure.
[00133] Additionally the control device can be configured to control the supply unit in order to supply electrical energy to the electrically conductive element of the peripheral, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of the said voltage, based on said calculated value of the actual temperature, on the desired value for the temperature of the heating surface of the heater.
[00134] In a 52nd aspect according to either of the two previous aspects in which the control device is connected to the second temperature sensor and is configured to receive said second temperature signal and control the supply unit in order to supplying power to the internal heater based on said second temperature signal and a desired value for said second temperature.
[00135] Alternatively, the control device is connected to said second electrical sensor, and is configured to:
[00136] - receive said electrical parameter signal and control the supply unit in order to supply electrical energy to the electrically conductive element of the internal heater, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of the said voltage, based on said electrical parameter signal and a desired value for a heater heating surface temperature.
[00137] Note that the control device can also be configured to receive said electrical parameter signal and calculate an actual temperature value of the carbon structure of the internal heater based on:
[00138] a value of said electrical parameter and
[00139] a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure.
[00140] Additionally, the control device can be configured to control the supply unit in order to supply electrical energy to the electrically conductive element of the internal heater, optionally by regulating the voltage applied to the electrically conductive element and/or the duration of applying said voltage, based on said calculated value of the actual temperature, to the desired value for the temperature of the heating surface of the heater.
[00141] In a 53rd aspect in accordance with any of the foregoing aspects in which:
[00142] - the upper tool comprises a heating head that has a respective active surface,
[00143] - the peripheral heater and the internal heater are both carried by said heating head,
[00144] - the heating head is configured to take a film sealing position, preferably in correspondence with said second operating condition of the upper and lower tools, wherein, in said film sealing position, at least the surface of heating the peripheral heater is configured to press against a corresponding top surface of said portion of film and permits a heat sealing of the portion of film to the at least one underlying support, and optionally wherein in said heat sealing position the surface of heating of said internal heater is configured to contact or be placed at a preset distance from the top surface of said portion of film, the control device being configured to control the packaging assembly in such a way that - during each said heating cycle - the heating head maintains said film sealing position at least during said first interval. distinct time interval, preferably until the expiration of said first distinct time interval.
[00145] In a 54th aspect in accordance with any of the foregoing aspects in which:
[00146] - the upper tool comprises a heating head that has a respective active surface,
[00147] - the peripheral heater and the internal heater are both carried by said heating head,
[00148] - the heating surface of the internal heater and the heating surface of the peripheral heater both have an annular shape and form part of said active surface, with the heating surface of the peripheral heater located at a radial distance from the heating surface of the heater internal and surrounding the same,
[00149] - in a position radially internal to the heating surface of the internal heater, the heating head has a central recess of fixed volume which - when the upper and lower tools are in said second operating condition - extends vertically away from the tool lower in order to define a space in which at least a part of a product located on a support positioned on one of said supports is capable of receiving;
[00150] In a 55th aspect according to any of the previous aspects of the 1st to the 53rd in which:
[00151] - the upper tool comprises a heating head with a respective active surface,
[00152] - the peripheral heater and the internal heater are both carried by said heating head,
[00153] - the heating surface of the peripheral heater and the heating surface of the internal heater rest on a plane in common with said active surface and which forms part of it, and
[00154] - the heating surface of the peripheral heater is located at a radial distance from and surrounding the heating surface of the internal heater.
[00155] In a 56th aspect in accordance with any of the previous aspects of the 1st to the 53rd in which:
[00156] - the upper tool comprises a heating head with a respective active surface,
[00157] - the peripheral heater and the internal heater are both carried by said heating head,
[00158] - the heating surface of the peripheral heater and the heating surface of the internal heater form part of said active surface,
[00159] - the heating head includes a central body that carries the internal heater and a peripheral body that carries the peripheral heater and surrounds the central body, the peripheral body and the central body being configured to be relatively mobile in order to form a central recess whose volume is determined by the relative position of the peripheral body in relation to the central body, said central recess being positioned in such a way that - when the upper and lower tools are in said second operating condition - it extends vertically away from the bottom tool to define a space in which at least a portion of a product located on a support is acceptable to receive.
[00160] In a 57th aspect according to any of the four foregoing aspects in which:
[00161] - the heating head includes means configured to be operative in correspondence with said active surface to retain one or more of said film portions in contact with the active surface;
[00162] or
[00163] - the apparatus includes retaining means configured to act on opposing longitudinal edges of said film to retain one or more of said portions of film in a position aligned with the heating head and said one or more supports.
[00164] In a 58th aspect according to any of the foregoing aspects wherein each of said supports is configured to receive a respective support having a base wall, a side wall emerging upstream from the base wall and a top edge which projects radially outward from said sidewall.
[00165] In a 59th aspect according to any of the foregoing aspects said apparatus further comprises:
[00166] - a support framework,
[00167] - a film supply assembly configured to supply a continuous film;
[00168] - a film cutting unit active in the continuous film and configured to at least transversally cut the continuous film; and
[00169] - a movie drive montage.
[00170] In a 60th aspect according to the previous aspect where the film cutter unit is located outside the wrapping assembly and where the film drive assembly is configured to drive the cutting of film sheets from the packaging unit. cutting into the packaging assembly and above one or more respective supports positioned on the respective supports;
[00171] Alternatively, the cutting unit is located within the packaging assembly and the film drive assembly is configured to drive continuous film from the film supply assembly into the packaging assembly and above one or more respective supports located on respective supports,
[00172] In a 61st aspect according to any of the four previous aspects in which the control device is connected to the packaging assembly and is configured to command the packaging assembly to go from the first to the second operating condition and vice versa -versa, said upper tool and lower tool cooperating in order to define a packaging chamber which - in correspondence with said second operating condition - is closed, optionally hermetically closed.
[00173] In a 62nd aspect according to the previous aspect the device comprises:
[00174] - a vacuum arrangement connected to the packaging chamber and configured to remove gas from said packaging chamber, the vacuum arrangement optionally comprising at least one vacuum pump and at least one evacuation tube connecting the interior of said packaging chamber to the vacuum pump,
[00175] said control unit is further configured to control the vacuum arrangement to remove gas from said packaging chamber at least when the packaging assembly is in said second operating condition with said hermetically closed packaging chamber.
[00176] In a 63rd aspect according to either of the two aspects above the apparatus comprises:
[00177] - a controlled atmosphere arrangement connected to the packaging chamber and configured to inject a gas stream into said packaging chamber, the controlled atmosphere arrangement optionally comprising at least one injection device and at least one injection tube that connects the interior of said packaging chamber to the injection device,
[00178] wherein said control unit is further configured to control said controlled atmosphere arrangement for injecting said gas stream at least when the packaging assembly is in said second operating condition with said hermetically closed packaging chamber ; wherein the controlled atmosphere arrangement is configured to inject gas into the packaging chamber that includes an amount of one or more of N2, O2 and CO2 that is different from the amount of these same gases as present in the atmosphere at 20°C and at the level of the sea (1 atmospheric pressure).
[00179] In a 64th aspect according to the previous aspect the apparatus includes both the vacuum arrangement and the controlled atmosphere arrangement and the control unit is configured to control said controlled atmosphere arrangement to begin injecting said stream of gas either after a preset delay of an activation of said vacuum arrangement or after a preset level of vacuum is reached within said packing chamber, optionally wherein said control unit is configured to control said controlled atmosphere arrangement to begin to inject said gas stream while said removal of gas from said packing chamber is still taking place.
[00180] In a 65th aspect according to any of the sixty-three aspects above the control device is configured to:
[00181] - receive a desired value for said/a first temperature (this value can be stored in a memory connected to the control device or can be received through a user interface connected to the control device),
[00182] - control the supply unit in order to supply power to the peripheral heater based on said desired value for said first temperature.
[00183] In a 66th aspect according to any of the previous sixty-four aspects the control device is configured to:
[00184] - receive a desired value for said/a second temperature (this value can be stored in a memory connected to the control device or can be received through a user interface connected to the control device),
[00185] - control the supply unit in order to supply energy to the internal heater based on said desired value for said second temperature.
[00186] In a 67th aspect according to any of the previous sixty-five aspects the control device is configured to:
[00187] - receive information identifying the type of film intended to be used (this information may be stored in a memory connected to the control device or may be received through a user interface connected to the control device) and determine a value desired for said first temperature based on said information; for example, the user can be prompted to select from numerous films usable on the device and based on the selection the desired value for the first temperature is set,
[00188] - control the supply unit in order to supply energy to the peripheral heater based on said desired value for said first temperature.
[00189] In a 68th aspect according to any of the sixty-six aspects above the control device is configured to:
[00190] - receive information identifying the type of film intended to be used (this information may be stored in a memory connected to the control device or may be received through a user interface connected to the control device) and determine a value desired for said second temperature based on said information; for example, the user can be prompted to select from numerous films usable on the device and based on the selection the desired value for the first temperature is set,
[00191] - control the supply unit in order to supply energy to the internal heater based on said desired value for said second temperature.
[00192] A 69th aspect concerns the use of an apparatus according to any one of the preceding claims to package a product (P) with the use of a support on which the product is positioned and a shrinkable type film to hot which is heat sealed to the backing.
[00193] A 70th aspect concerns the use of an apparatus according to any one of the preceding claims to package a product (P) with the use of a tray with a tray base, a tray side wall and a flange edge. tray top where the product is positioned within the tray and where a heat shrinkable type film is heat sealed to the top surface of the tray edge.
[00194] In a 71st aspect according to either of the two aspects above the internal heater is brought to the second temperature after: the peripheral heater comes into contact with the film, with the film in contact with the support or the tray, and after the peripheral heater heating surface is brought to the first temperature.
[00195] A 72nd aspect concerns a process of packaging a product disposed on a support, using an apparatus according to any one of the preceding claims, the process comprising the following steps:
[00196] - to position one or more supports in correspondence with said one or more supports,
[00197] - positioning at least one portion of film (which may be in the form of a longitudinal portion of a continuous sheet or in the form of a separate precut sheet of film) above a respective one or more supports located on said one or more supports,
[00198] - keep the first and second tools in said first operating condition for a sufficient time for the supports and for the corresponding film portion to position itself properly,
[00199] - moving the upper and lower tools in said second operating condition with said portion of film positioned above the respective support or supports,
[00200] - heat seal the film portion to the support, the heat sealing step including the following substeps:
[00201] cause the heating surface of the peripheral heater to contact the top surface of the film portion of the support or supports located on said support or on said supports,
[00202] increase a temperature of the heating surface of the peripheral heater to a first temperature,
[00203] maintain the heating surface of the peripheral heater at least at the first temperature for a first distinct time interval,
[00204] reduce the temperature of the heating surface of the peripheral heater below said first temperature,
[00205] cause the heating surface of the internal heater to come into contact or be placed at a preset distance from the top surface of said film portion,
[00206] increase an internal heater heating surface temperature to a second temperature, maintain the internal heater heating surface at least at the second temperature for a second distinct time interval, reduce the temperature of the internal heater heating surface below of said second temperature,
[00207] - position the upper and lower tools in said first operating condition,
[00208] - move the amount of supports with the film firmly fixed away from the packaging assembly.
[00209] In a 73rd aspect according to the previous aspect the second temperature is different from the first temperature.
[00210] In a 74th aspect according to the previous aspect the second temperature is below the first temperature.
[00211] A 75th aspect according to any of the above three aspects the film is a heat shrinkable film.
[00212] In a 76th aspect in accordance with any of the four foregoing aspects the support is a tray having a base wall and a side wall with a top lip which emerges radially outward from the side wall.
[00213] In a 77th aspect according to the previous aspect the step of making the heating surface of the peripheral heater contact the top surface of the film portion of the support or supports located on said support or in the said supports comprise bringing the heating surface of the peripheral heater into contact with the peripheral region of the film portion and the latter in contact with the top surface of the top edge of the tray.
[00214] In a 78th aspect according to any of the six aspects above wherein the heating surface of the peripheral heater is held in contact with the film portion until after the heating surface of the peripheral heater is cooled to a temperature below the first temperature, for example, to a reference temperature that is at least 50°C below the first temperature.
[00215] In a 79th aspect according to any of the previous seven aspects in which the process includes the following additional steps that happen with the film held at a distance from the support sufficient to allow gas circulation within the support,
[00216] - with the upper and lower tools defining in said second operating condition a hermetically closed packaging chamber, in order to cause one or both of: a removal of gas from the hermetically closed packaging chamber and an injection of gas into the packaging chamber of a gas mixture of controlled composition.
[00217] In an 80th aspect according to any of the eight aspects above, the steps of:
[00218] cause the heating surface of the peripheral heater to contact the top surface of the film portion of the support or supports located on said support or on said supports,
[00219] increase a peripheral heater heating surface temperature to a first temperature,
[00220] maintain the heating surface of the peripheral heater at least at the first temperature for a first distinct time interval,
[00221] reduce the temperature of the heating surface of the peripheral heater below said first temperature,
[00222] are timely sequential steps.
[00223] In an 81st aspect according to any of the previous nine aspects the step of heat sealing includes heating with the peripheral heater a peripheral band of said portion of film (or film sheet) and heating with the internal heater a inner zone of the same portion of film (or sheet of film) located radially within the peripheral band.
[00224] In an 82nd aspect according to any of the previous ten aspects the first distinct time period has a duration comprised between 0.2 and 5 seconds.
[00225] In an 83rd aspect according to any one of the eleven foregoing aspects the first distinct time period has a duration of between 0.5 and 1.5 seconds.
[00226] In an 84th aspect according to any of the twelve foregoing aspects the second distinct time period has a duration of between 0.2 and 5 seconds, optionally the second distinct time period has a duration of between 0.5 and 1.5 seconds.
[00227] In an 85th aspect according to any one of the fourteen aspects above during the heat sealing step the increase in the temperature of the heating surface of the internal heater to a second temperature starts after the increase in the temperature of the peripheral heater until the first temperature, wherein the start of said second distinct time interval is delayed relative to the start of said first time interval.
[00228] In particular the start of the second distinct time interval can be delayed until the moment when the heat sealing surface touches the film portion and the latter touches the support. According to another option, the second distinct time interval can be delayed until after reducing the temperature of the heating surface of the peripheral heater below said first temperature (in other words the cooling of the peripheral heater can start before the heating of the internal heater be started).
[00229] In an 86th aspect according to the preceding aspect wherein the duration of said first distinct time interval is greater than the duration of said second distinct time interval.
[00230] In an 87th aspect according to any of the sixteen aspects above, the process includes the steps of removing gas from the hermetically closed packaging chamber, until a pressure comprised between 10 and 30 KPa (100 and 300 mbar), optionally between 15 and 25 KPa (150 and 250 mbar), is reached within said packaging chamber and then - while the film portion or film sheet is kept at a distance from the support nozzle - injecting a modified atmosphere gas into the packing chamber (), optionally in which the injection of said gas stream to create a modified atmosphere takes place while a gas removal still takes place in order to shorten the time to create the modified atmosphere.
[00231] In an 88th aspect according to any of the previous seventeen aspects, the increase in the temperature of the heating surface of the internal heater to a second temperature starts after the increase in the temperature of the peripheral heater to the first temperature: optionally heating of the internal heater to the second temperature, starts at least 0.1, preferably 0.25 seconds, after heating the peripheral heater to the first temperature. In other words, the start of the second distinct time interval may be slightly delayed in relation to the start of said first time interval in order to avoid (when using a heat shrinkable film) causing a slippage of the peripheral film portion to be sealed to the edge. In particular, the start of the second time interval can be delayed until the moment when the heat sealing surface touches the film portion and the latter touches the backing. According to another option, the second distinct time interval can be delayed until after the end of the first time interval, for example, until the temperature reduction of the heating surface of the peripheral heater below said first temperature occurs (in others words the peripheral heater cooling may start before the internal heater heating starts).
[00232] In an 89th aspect according to any of the foregoing eighteen aspects the process also includes cooling said internal heater and said peripheral heater by circulating a coolant (water or oil or other fluid) in a cooling circuit adjacent to the heating surfaces in order to obtain a sudden temperature reduction of the heating surfaces of the internal and peripheral heaters after said first and second distinct time intervals.
[00233] In a 90th aspect according to any one of the nineteen foregoing aspects wherein said rise to the first temperature is a sudden rise in temperature of the heating surface of the peripheral heater from a respective reference temperature to the first temperature. By sudden increase is meant increasing said temperature of the heating surface of the peripheral heater with a rate of temperature increase with time greater than 1°C/ms, optionally greater than 5°C/ms.
[00234] In a 91st aspect according to any one of the twenty aspects above said increase to the second temperature is a sudden increase in the temperature of the heating surface of the internal heater from a respective reference temperature to the second temperature. By sudden increase is meant increasing said temperature of the heating surface of the internal heater with a rate of temperature increase with time greater than 1°C/ms, optionally greater than 5°C/ms.
[00235] In a 92nd aspect according to any one of the twenty-one foregoing aspects wherein said first temperature reduction is a sudden decrease in the temperature of the peripheral heater heating surface from the first temperature to a respective reference temperature. By sudden decrease is meant decreasing said temperature of the heating surface of the peripheral heater with a rate of temperature decrease with time greater than 1°C/ms, optionally greater than 5°C/ms.
[00236] In a 93rd aspect according to any one of the twenty-two foregoing aspects said second temperature reduction is a sudden decrease in the temperature of the heating surface of the second temperature internal heater to a respective reference temperature. By sudden decrease is meant decreasing said temperature of the heating surface of the internal heater with a rate of temperature decrease with time greater than 1°C/ms, optionally greater than 5°C/ms.
[00237] A 94th aspect concerns a heater assembly for a packaging assembly that has:
[00238] a heater with a heating surface configured to heat seal one or more parts of a plastic film, the heater comprising at least one electrically conductive element, and
[00239] a supply unit connected to the electrically conductive element of the heater and configured to supply electrical energy to said heater causing a flow of electrical current through said electrically conductive element,
[00240] wherein the electrically conductive element comprises an electrically conductive carbon structure.
[00241] In more detail, the electrically conductive carbon structure includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[00242] a graphite structure,
[00243] a single-layer or multi-layer graphene structure,
[00244] a fullerene structure, in which carbon atoms are linked together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00245] It should be noted that the electrically conductive element may be formed of an electrically conductive carbon structure completely formed into one or more of the carbon allotropes disclosed above.
[00246] For example, the electrically conductive element can be uniquely formed in graphite, or the electrically conductive element can be uniquely formed in a single layer of graphene, or the electrically conductive element can be uniquely formed in a plurality of layers of graphene that overlap each other, or the electrically conductive element may be uniquely formed into a carbon nanotube fullerene structure, or the electrically conductive element may be formed into a carbon nanofiber fullerene structure.
[00247] According to a further variant the carbon structure may comprise a structure formed by carbon filaments that are in contact adjacent to each other to form a conductive body or by carbon filaments embedded in a resin matrix Plastic: In the latter case the carbon filaments can be placed adjacently and electrically connected to each other in prescribed sections such as at their ends.
[00248] In a 95th aspect according to the previous aspect the electrically conductive element comprises a structural substrate bearing the carbon structure and at least one protective layer covering the carbon structure on an opposite side to the same of the structural substrate, optionally wherein said carbon structure is sandwiched between two opposing protective layers, wherein, in addition, the protective layer opposite the structural substrate defines the heating surface of said heater.
[00249] In a 96th aspect according to either of the two foregoing aspects the carbon structure comprises or is uniquely formed of a plurality of mutually overlapping graphene layers defining a flat elongated shaped carbon structure.
[00250] In a 97th aspect according to any of the three foregoing aspects the carbon structure comprises a cross section having a thickness of at least 5 µm and a width of at least 2 mm, optionally a cross section having a thickness of at least 10 µm and a width of at least 5 mm.
[00251] In a 98th aspect according to any of the four previous aspects the carbon structure presents an average electrical resistivity greater than 5 Qwm2/m, which is optionally comprised between 15 and 25 frmm2/m.
[00252] A 99th aspect concerns a packaging apparatus that includes:
[00253] a packaging assembly configured to receive a product (P) to be packaged and at least one film to package the product (P),
[00254] and a heating assembly associated with the packaging assembly, wherein the heating assembly is in accordance with any of the above five aspects.
[00255] A 100th aspect concerns a packaging apparatus of the previous aspect in which:
[00256] said packaging assembly is configured to receive at least one support and to firmly fix the film to the support, the packaging assembly including:
[00257] - a lower tool that defines a predetermined amount of supports configured to receive said at least one support with a product (P) to be packaged,
[00258] - an upper tool facing the lower tool and cooperating with it,
[00259] wherein said upper tool and said lower tool are relatively mobile at least between a first operating condition, wherein the upper tool and the lower tool are spaced apart and allows the positioning of at least a portion of film of said film above one or more of said at least one support, and a second operating condition, in which the upper tool and the lower tool are brought closer together and allows a heat sealing of said portion of film to o at least one support located on said one or more supports,
[00260] said heater comprises a peripheral heater loaded by the upper tool, and wherein the electrically conductive element comprises a first electrically conductive element that forms part of the peripheral heater, wherein the peripheral heater is configured to heat seal at least one region peripheral of said film portion to the at least one support.
[00261] A 101st aspect concerns an apparatus of the previous aspect or a heating assembly according to any one of the previous seven aspects which further comprises a control device which acts on the supply unit and is configured to command the supply unit. supplying and controlling a supply of electrical energy to the heater, said control device being further configured to command the supply unit to perform a heating cycle which includes the following steps:
[00262] apply an electrical voltage to the electrically conductive element to cause the heater's heating surface temperature to rise to a first temperature,
[00263] maintain said electrical voltage to maintain the heating surface of the heater at least at the first temperature for a first distinct time interval,
[00264] reduce or nullify the voltage applied to the electrically conductive element to reduce the temperature of the heating surface of the heater below said first temperature.
[00265] A 102nd aspect concerns a heating apparatus or assembly of the above aspect wherein the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and in which the electrical voltage is maintained applied to the electrically conductive element for a period of time substantially equal to the first distinct period of time.
[00266] In a 103rd aspect according to any of the three aspects above, the heater of the apparatus is carried by a heating head of said packaging assembly, the heating heat being movable from a rest position, in that it is spaced from the film to be heat sealed, to a film sealing position, in which the heating surface of the heater contacts a film to be sealed surface, in which, in addition, the control device is configured to control the packaging assembly in such a way that - during each said heating cycle - the heating head maintains said film sealing position at least during said first distinct time interval, preferably until the expiration of said first distinct time interval.
[00267] In a 104th aspect it concerns an apparatus of any of the four previous aspects or a heating assembly of any of the nine previous aspects wherein the electrical source unit comprises:
[00268] - at least one pulse transformer configured to generate voltage pulses of a duration - intended as a total duration of the pulse sequence - comprised between 0.1 second and 5 seconds, optionally between 0.2 and 1.5 seconds.
[00269] - at least one set of electrical circuits that connect the impulse transformer to the electrically conductive element,
[00270] wherein said control device is configured to act on the supply unit to supply electric current at a predetermined voltage and for a predetermined period of time said electrically conductive element.
[00271] A 105th aspect concerns an apparatus of any one of the above five aspects or a heating assembly of any of the ten above aspects comprising
[00272] - a first temperature sensor configured to detect a heater heating surface temperature and output a corresponding first temperature signal correlated to the detected temperature,
[00273] in which the control device is connected to said first temperature sensor, and is configured to:
[00274] - receive said first temperature signal and control the supply unit in order to supply electrical energy to the electrically conductive element, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said first temperature signal and a desired value for said first temperature.
[00275] A 106th aspect concerns an apparatus of any of the six aspects above, wherein the heater further comprises an internal heater also carried by the upper tool and having a heating surface configured to heat at least a portion of said portion of film, wherein the peripheral heater surrounds the internal heater, and wherein the electrically conductive element comprises a second electrically conductive element that forms part of the internal heater,
[00276] the control device is further configured to control the supply unit in order to supply electrical power to the first electrically conductive element independently of a power supply to the second electrically conductive element,
[00277] wherein additionally said heating cycle includes the following additional steps:
[00278] apply an electrical voltage to the second electrically conductive element to cause the internal heater heating surface temperature to rise to a second temperature different from the first temperature,
[00279] maintain said electrical voltage applied to the second electrically conductive element to maintain the heating surface of the internal heater at least at the second temperature for a second distinct time interval,
[00280] reduce or nullify the voltage applied to the second electrically conductive to reduce the temperature of the heating surface of the internal heater below said second temperature.
[00281] According to this aspect, the device may additionally include the following features:
[00282] - a first temperature sensor configured to detect a temperature of the heating surface of the peripheral heater and output a corresponding first temperature signal correlated to the detected temperature. Note that the first temperature sensor can be a contact temperature sensor or a non-contact temperature sensor (for example, an IR sensor);
[00283] - since the presence of the first temperature sensor may not be necessary, a temperature of the heating surface can be calculated based on the measured electrical resistance of the first electrically conductive element.
[00284] For example, a first electrical sensor can be used: the first electrical sensor is electrically connected or connectable to the carbon structure of the peripheral heater and configured to detect an electrical parameter of said carbon structure and emit a corresponding electrical parameter signal , in which the electrical parameter comprises one of:
[00285] an electrical impedance of a prefixed segment of said carbon structure,
[00286] an electrical current flowing through said prefixed segment of carbon structure when a prefixed electrical voltage is applied at ends of said prefixed segment,
[00287] an electrical voltage detected at the ends of the prefixed segment when a prefixed electrical current is imposed to flow through said prefixed segment.
[00288] - a second temperature sensor to detect a temperature of the heating surface of the internal heater and output a second corresponding temperature signal correlated to the detected temperature. Note that the second temperature sensor can be a contact temperature sensor or a non-contact temperature sensor (for example, an IR sensor);
[00289] - since the presence of the second temperature sensor may not be necessary, the temperature of the heating surface can be calculated based on the measured electrical resistance of the second electrically conductive element.
[00290] For example, a second electrical sensor can be used; the second electrical sensor is electrically connected or connectable to the carbon structure of the internal heater and is configured to detect an electrical parameter of said carbon structure and emit a corresponding electrical parameter signal: the electrical parameter comprises one of:
[00291] an electrical impedance of a prefixed segment of said carbon structure,
[00292] an electrical current flowing through said prefixed segment of carbon structure when a prefixed electrical voltage is applied at ends of said prefixed segment,
[00293] an electrical voltage detected at the ends of the prefixed segment when a prefixed electrical current is imposed to flow through said prefixed segment.
[00294] The control device can be connected to said first temperature sensor and be configured to:
[00295] - receiving said first temperature signal and controlling the supply unit in order to supply power to the peripheral heater based on said first temperature signal and a desired value for said first temperature.
[00296] Alternatively the control device can be connected to said first electrical sensor, and be configured to:
[00297] - receive said electrical parameter signal and control the supply unit in order to supply electrical energy to the electrically conductive element of the peripheral heater, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of the said voltage, based on said electrical parameter signal and a desired value for a heater heating surface temperature.
[00298] Note that the control device can also be configured to receive said electrical parameter signal and calculate an actual temperature value of the carbon structure of the peripheral heater based on:
[00299] a value of said electrical parameter and
[00300] a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure.
[00301] Additionally the control device can be configured to control the supply unit in order to supply electrical energy to the electrically conductive element of the peripheral heater, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said calculated value of the actual temperature, to the desired value for the temperature of the heating surface of the heater.
[00302] The control device may also be connected to the second temperature sensor and be configured to receive said second temperature signal and control the supply unit in order to supply power to the internal heater based on said second temperature signal and at a desired value for said second temperature.
[00303] Alternatively, the control device can be connected to said second electrical sensor, and is configured to:
[00304] - receive said electrical parameter signal and control the supply unit in order to supply electrical energy to the electrically conductive element of the internal heater, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of the said voltage, based on said electrical parameter signal and a desired value for a heater heating surface temperature.
[00305] Note that the control device can also be configured to receive said electrical parameter signal and calculate an actual temperature value of the carbon structure of the internal heater based on:
[00306] a value of said electrical parameter and
[00307] a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure.
[00308] Additionally, the control device can be configured to control the supply unit in order to supply electrical energy to the electrically conductive element of the internal heater, optionally by regulating the voltage applied to the electrically conductive element and/or the duration of applying said voltage, based on said calculated value of the actual temperature, to the desired value for the temperature of the heating surface of the heater.
[00309] A 107th aspect concerns an apparatus of any of the seven aspects above, in which:
[00310] - said control device is configured to command the supply unit to consecutively repeat the execution of said heating cycle a plurality of times, during each of said consecutive heating cycles at least one of said portions of film is heat sealed in at least one respective support,
[00311] - said control device - during each heating cycle - is configured to control the supply unit in order to supply power to the first electrically conductive element of the peripheral heater only for a distinct period of time followed by a period of time when no energy is supplied to cause the heating surface of the peripheral heater to rise and maintain at least the first temperature for the first distinct time interval, and to cause a subsequent reduction in the temperature of the heating surface of the peripheral heater below said first temperature, optionally - said control device - during each heating cycle - is configured to control the supply unit in order to supply power to the second electrically conductive element of the internal heater only for a distinct period of time followed by a period of time when no energy is supplied to cause the increase and to maintain the heating surface of the internal heater at least at the second temperature for the second distinct time interval, and to cause a subsequent reduction in the temperature of the heating surface of the internal heater below said second temperature.
[00312] A 108th aspect concerns an apparatus of any of the eight aspects above in which the heating cycle is configured in such a way that the second temperature is lower than the first temperature, and in which
[00313] - said first temperature is comprised between 150°C and 260°C, optionally between 180 to 240°C, more optionally between 200 to 220°C;
[00314] - said second temperature (if there is a second heater or internal heater) is comprised between 150°C and 260°C, optionally between 180 to 240°C, more optionally between 200 to 220°C.
[00315] wherein additionally the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and
[00316] wherein optionally the second distinct time period has a duration comprised between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds;
[00317] A 109th aspect concerns an apparatus among any of the previous nine aspects in which additionally the control device is configured to command the supply unit to sharply increase the temperature of the heating surface of the peripheral heater by a respective temperature reference to first temperature with a rate of temperature rise with time greater than 1°C/ms, optionally greater than 5°C/ms;
[00318] wherein optionally additionally the control device is configured to command the supply unit to sharply increase the temperature of the heating surface of the internal heater from a respective reference temperature to the second temperature with a rate of temperature increase with the time greater than 1°C/ms, optionally greater than 5°C/ms.
[00319] A 110th aspect concerns an apparatus of any of the four previous aspects in which each heating cycle is configured in such a way that increasing the temperature of the heating surface of the internal heater to a second temperature starts after the increase from the temperature of the peripheral heater to the first temperature, with the start of said second distinct time interval being delayed in relation to the beginning of said first time interval, optionally wherein the start of said second distinct time interval is immediately after the end of the first time slot, more optionally wherein the duration of said first distinct time slot is greater than the duration of said second distinct time slot.
[00320] A 111th aspect concerns an apparatus of any of the five previous aspects in which:
[00321] - the heating surface of said peripheral heater has an annular shape and surrounds the heating surface of the internal heater, and
[00322] - when the upper and lower tools are in said second operating position, the peripheral heater is configured to heat a peripheral band of said film portion while the internal heater is configured to heat at least a part of an internal zone thereof film portion located radially within the peripheral band.
[00323] A 112th aspect concerns an apparatus of any of the six previous aspects in which:
[00324] - both the heating surface of the peripheral heater and the heating surface of the internal heater are flat and
[00325] - at least when the upper and lower tools are in said second operating position, the heating surface of the peripheral heater is:
[00326] or coplanar to the heating surface of the internal heater or
[00327] indented with respect to the peripheral surface of the internal heater, such that when the heating surface of the peripheral heater is in contact with the top surface of the film portion, the heating surface of the internal heater is offset by a distance prefixed from the top surface of the same film portion.
[00328] A 113th aspect concerns an apparatus of any of the seven foregoing aspects in which the heating surface of the internal heater is located at a radial distance from the heating surface of the peripheral heater and extends into an area surrounded by the surface heater heating surface, said internal heater heating surface comprising one selected from the group among:
[00329] - an annular-shaped heating surface,
[00330] - a continuous heating surface delimited by a single closed contour line, optionally a discoidal or polygonal continuous heating surface, the continuous heating surface occupying substantially all or a majority of said area surrounded by the heating surface of the heater peripheral,
[00331] - a heating surface that includes a plurality of spaced parallel strips connected at their ends by transverse strips.
[00332] A 114th aspect concerns an apparatus of any of the eight aspects above in which the first electrically conductive element of the peripheral heater extends along the heating surface of the peripheral heater, the first electrically conductive element being a electrically conductive annular element, optionally an electrically conductive annular flat element, having an electrically conductive carbon structure comprising (or exclusively formed of) one or more carbon allotropes in the group of:
[00333] a graphite structure,
[00334] a single-layer or multi-layer graphene structure,
[00335] a fullerene structure, in which carbon atoms are linked together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00336] It should be noted that the first electrically conductive element may be formed of an electrically conductive carbon structure completely formed in one or more of the carbon allotropes disclosed above.
[00337] For example, the first electrically conductive element may be exclusively formed in graphite, or the first electrically conductive element may be exclusively formed in a single layer of graphene, or the first electrically conductive element may be exclusively formed in a plurality of layers of mutually overlapping graphene, or the first electrically conductive element can be uniquely formed in a fullerene structure of carbon nanotubes, or the first electrically conductive element can be formed in a fullerene structure of carbon nanofibers.
[00338] According to a further variant the carbon structure may comprise a structure formed by carbon filaments that are in contact adjacent to each other in order to form a conductive body or by carbon filaments embedded in a resin matrix Plastic: In the latter case the carbon filaments can be placed adjacently and electrically connected to each other in prescribed sections such as at their ends.
[00339] As for the second electrically conductive element of the internal heater, it extends along the heating surface of the internal heater, and said second conductive element is one selected from the group among:
[00340] an electrically conductive annular element, optionally an electrically conductive annular flat element, which has an electrically conductive carbon structure;
[00341] an electrically conductive continuous plate, which has an electrically conductive carbon structure;
[00342] an electrically conductive meander element, optionally an electrically conductive flat meander element, which has an electrically conductive carbon structure.
[00343] The second electrically conductive element (for example, in the form of a meander or plate or flat annular shaped element) comprises an electrically conductive carbon structure; the electrically conductive carbon structure includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[00344] a graphite structure,
[00345] a single-layer or multi-layer graphene structure,
[00346] a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00347] It should be noted that the second electrically conductive element may be formed of an electrically conductive carbon structure completely formed in one or more of the carbon allotropes disclosed above.
[00348] For example, the second electrically conductive element can be exclusively formed in graphite, or the second electrically conductive element can be exclusively formed in a single layer of graphene, or the second electrically conductive element can be exclusively formed in a plurality of layers of mutually overlapping graphene, or the second electrically conductive element can be uniquely formed in a carbon nanotube fullerene structure, or the second electrically conductive element can be formed in a carbon nanofiber fullerene structure.
[00349] According to a further variant the carbon structure may comprise a structure formed by carbon filaments that are in contact adjacent to each other in order to form a conductive body or by carbon filaments embedded in a resin matrix Plastic: In the latter case the carbon filaments can be placed adjacently and electrically connected to each other in prescribed sections such as at their ends.
[00350] A 115th aspect concerns an apparatus of any of the previous nine aspects the first electrically conductive element comprises a structural substrate bearing a respective carbon structure and at least one protective layer covering the carbon structure on one side opposite the same as the structural substrate, optionally wherein said carbon structure is sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said peripheral heater; optionally with the carbon structure of the first electrically conductive element comprising a plurality of mutually overlapping graphene layers forming a flat-shaped carbon structure.
[00351] In a 116th aspect according to the previous aspect the carbon structure of the first electrically conductive element of the peripheral heater has a cross section having a thickness of at least 5 μm and a width of at least 3 mm, plus optionally a cut. transversal with a thickness of at least 10 μm and a width of at least 5 mm, and an average electrical resistivity greater than 5 Q«mm2/m, which is optionally between 15 and 25 Q«mm2/m.
[00352] A 117th aspect concerns an apparatus of any of the eleven foregoing aspects in which the second electrically conductive element comprises a structural substrate bearing a respective carbon structure and at least one protective layer covering the carbon structure in an opposite side thereto of the structural substrate, optionally wherein said carbon structure is sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said internal heater; optionally with the carbon structure of the second electrically conductive element comprising a plurality of mutually overlapping graphene layers forming a flat-shaped carbon structure.
[00353] In a 118th aspect according to the previous aspect the carbon structure of the second electrically conductive element of the internal heater has a cross section having a thickness of at least 5 μm and a width of at least 5 mm, plus optionally a cut transversal with a thickness of at least 10 µm and a width of at least 10 mm, and an average electrical resistivity greater than 2Q^mm2/m, optionally greater than 5Q^mm2/m.
[00354] A 120th aspect concerns an apparatus of any of the thirteen foregoing aspects comprising a cooling circuit associated with the upper tool and configured to cool said internal heater and said peripheral heater, wherein the cooling circuit is controlled by the control device which is further configured to cause circulation of a coolant in said cooling circuit and to regulate a coolant temperature.
[00355] A 121st aspect concerns an apparatus of any of the fourteen aspects above in which the electrical source unit comprises:
[00356] - at least one electrical impulse transformer,
[00357] - at least one set of electrical circuits connecting the electrical impulse transformer to the first electrically conductive element and the second electrically conductive element;
[00358] or
[00359] - at least a first electrical impulse transformer and a first set of electrical circuits connecting the first electrical impulse transformer to the first electrically conductive element, and
[00360] - at least one second electrical impulse transformer and a second set of electrical circuits connecting the second electrical impulse transformer to the second electrical impedance,
[00361] wherein said control device is configured to act on the electrical source unit to independently supply an electrical current at a predetermined voltage to said first and, respectively, second electrically conductive element.
[00362] A 122nd aspect concerns an apparatus of any of the fifteen aspects above, which additionally includes:
[00363] - a first temperature sensor configured to detect a temperature of the heating surface of the peripheral heater and issue a first corresponding temperature signal correlated to the detected temperature,
[00364] - a second temperature sensor to detect a temperature of the heating surface of the internal heater and issue a second corresponding temperature signal correlated to the detected temperature,
[00365] in which the control unit is connected to said first temperature sensor, and to said second temperature sensor, and is configured to:
[00366] - receive said first temperature signal and control the supply unit in order to supply power to the first electrically conductive element, optionally regulating the voltage applied to the first electrically conductive element and/or the duration of application of said voltage , based on said first temperature signal and a desired value for said first temperature,
[00367] - receive said second temperature signal and control the supply unit in order to supply power to the second electrically conductive element, optionally regulating the voltage applied to the second electrically conductive element and/or the duration of application of said voltage , based on said second temperature signal and a desired value for said second temperature.
[00368] A 123rd aspect concerns an apparatus of any of the sixteen aspects above in which:
[00369] - the upper tool comprises a heating head that has a respective active surface,
[00370] - the peripheral heater and the internal heater are both carried by said heating head,
[00371] - the heating head is configured to take a film sealing position, preferably in correspondence with said second operating condition of the upper and lower tools, wherein in said film sealing position at least the heating surface of the peripheral heater is configured to press against a corresponding top surface of said film portion and permits a heat sealing of the film portion to the at least one underlying support, and optionally wherein in said heat sealing position the heating surface of the said internal heater is configured to contact or be placed at a preset distance from the top surface of said film portion,
[00372] the control device is configured to control the packaging assembly in such a way that - during each said heating cycle - the heating head maintains said film sealing position at least during said first distinct time interval, preferably until the expiration of said first distinct time interval.
[00373] A 124th aspect concerns an apparatus of any of the previous seventeen aspects in which:
[00374] - the upper tool comprises a heating head that has a respective active surface,
[00375] - the peripheral heater and the internal heater are both carried by said heating head,
[00376] - the heating surface of the internal heater and the heating surface of the peripheral heater both have an annular shape and form part of said active surface, with the heating surface of the peripheral heater located at a radial distance from the heating surface of the heater internal and surrounding the same,
[00377] - in a position radially internal to the heating surface of the internal heater, the heating head has a central recess of fixed volume which - when the upper and lower tools are in said second operating condition - extends vertically away from the tool lower in order to define a space in which at least a part of a product located on a support positioned on one of said supports is capable of receiving;
[00378] or in which:
[00379] - the upper tool comprises a heating head with a respective active surface,
[00380] - the peripheral heater and the internal heater are both carried by said heating head,
[00381] - the heating surface of the peripheral heater and the heating surface of the internal heater rest on a plane in common with said active surface and that forms part of it, and
[00382] - the heating surface of the peripheral heater is located at a radial distance from and surrounding the heating surface of the internal heater;
[00383] or in which
[00384] - the upper tool comprises a heating head with a respective active surface,
[00385] - the peripheral heater and the internal heater are both carried by said heating head,
[00386] - the heating surface of the peripheral heater and the heating surface of the internal heater form part of said active surface,
[00387] - the heating head includes a central body that carries the internal heater and a peripheral body that carries the peripheral heater and surrounds the central body, the peripheral body and the central body being configured to be relatively mobile in order to form a central recess whose volume is determined by the relative position of the peripheral body in relation to the central body, said central recess being positioned in such a way that - when the upper and lower tools are in said second operating condition - it extends vertically away from the bottom tool to define a space in which at least a portion of a product located on a support is acceptable to receive.
[00388] A 125th aspect concerns an apparatus of any of the eighteen aspects above, in which:
[00389] - the heating head includes means configured to be operative in correspondence with said active surface to retain one or more of said film portions in contact with the active surface;
[00390] or
[00391] - the apparatus includes a retaining means configured to act on opposite longitudinal edges of said film to retain one or more of said film portions in a position aligned with the heating head and said one or more supports.
[00392] A 126th aspect concerns an apparatus of any of the nineteen foregoing aspects wherein each of said supports is configured to receive a respective support having a base wall, a side wall emerging upstream of the wall of base and a top edge that projects radially outward from said sidewall,
[00393] said apparatus which additionally comprises:
[00394] - a support framework,
[00395] - a film supply assembly configured to supply a continuous film;
[00396] - a film cutting unit active in the continuous film and configured to at least transversely cut the continuous film, wherein the film cutting assembly is located outside the packaging assembly or within the packaging assembly,
[00397] - a film drive assembly, which - if the cutting unit is located outside the packaging assembly - is configured to drive the cutting of film sheets from the cutting unit into the packaging assembly and above an or plus respective supports positioned on the respective supports or that - if the cutting unit is located within the packaging assembly - is configured to drive the continuous film from the film supply assembly into the packaging assembly and above one or more respective supports located on respective supports,
[00398] in which the control device is connected to the packaging assembly and is configured to command the packaging assembly to go from the first to the second operating condition and vice versa, with the upper tool () and the lower tool () cooperate in order to define a packing chamber which - in correspondence with said second operating condition - is closed, optionally hermetically closed.
[00399] A 127th aspect concerns an apparatus of any of the twenty aspects above which comprises at least one of:
[00400] - a vacuum arrangement connected to the packaging chamber and configured to remove gas from said packaging chamber, the vacuum arrangement optionally comprising at least one vacuum pump and at least one evacuation tube connecting the interior of the said packaging chamber to the vacuum pump,
[00401] said control unit is further configured to control the vacuum arrangement to remove gas from said packaging chamber at least when the packaging assembly is in said second operating condition with said hermetically sealed packaging chamber; and
[00402] - a controlled atmosphere arrangement connected to the packaging chamber and configured to inject a gas stream into said packaging chamber, the controlled atmosphere arrangement optionally comprising at least one injection device and at least one injection tube that connects the interior of said packaging chamber to the injection device,
[00403] said control unit is further configured to control said controlled atmosphere arrangement for injecting said gas stream at least when the packaging assembly is in said second operating condition with said hermetically closed packaging chamber; wherein the controlled atmosphere arrangement is configured to inject gas into the packaging chamber that includes an amount of one or more of N2, O2 and CO2 that is different from the amount of these same gases as present in the atmosphere at 20°C and at the level of the sea (1 atmospheric pressure),
[00404] wherein optionally the apparatus includes both the vacuum arrangement and the controlled atmosphere arrangement and wherein the control unit is configured to control said controlled atmosphere arrangement to begin injecting said gas stream either after a delay preset from an activation of said vacuum arrangement or after a preset vacuum level has reached the interior of said packing chamber
[00405] more optionally wherein said control unit is configured to control said controlled atmosphere arrangement to begin injecting said gas stream while said gas removal from said packing chamber still takes place.
[00406] A 128th aspect concerns an apparatus of any of the twenty-one aspects above in which the control device is configured to:
[00407] - receive a desired value for said first temperature and a desired value for said second temperature, optionally through a user interface connected to the control device, or
[00408] - receive information identifying the type of film intended to be used, optionally through a user interface connected to the control device, and determine a desired value for said first temperature and said second temperature based on said information ;
[00409] - control the supply unit in order to supply power to the peripheral heater based on said desired value for said first temperature,
[00410] - control the supply unit in order to supply energy to the internal heater based on said desired value for said second temperature.
[00411] A 129th aspect concerns an apparatus of any of the foregoing aspects relating to an apparatus for packaging a product (P):
[00412] - by heat sealing a heat shrinkable film to support on which said product (P) was previously placed or
[00413] - by positioning at least one shrinkable film around the product (P) and then heat sealing one or more portions of said heat shrinkable film to each other.
[00414] A 130th aspect concerns a process of packaging a product (P) arranged on a support, said support having a base wall and a side wall, and said process uses an apparatus in accordance with any of the above aspects directed to a device, and the process comprises the following steps:
[00415] - to position one or more supports in correspondence with said one or more supports,
[00416] - positioning at least a portion of film or at least one sheet of film above a respective one or more supports located on said one or more supports,
[00417] - keep the first and second tools in said first operating condition for a sufficient time for the supports and for the film portion or the corresponding film sheet in order to position properly,
[00418] - moving the upper and lower tools in said second operating condition with said portion of film or film sheet positioned above the respective support or respective supports, optionally at a sufficient distance to allow a gas circulation within the support ( 4),
[00419] - optionally wherein in said second operating condition the upper and lower tools define a hermetically closed packaging chamber with the process that includes causing one or both of: a removal of gas from the hermetically closed packaging chamber and a gas injection in the packaging chamber of a gas mixture of controlled composition,
[00420] - heat seal the film portion or the film sheet to support the heat sealing step that includes the following substeps:
[00421] cause the heating surface of the peripheral heater to contact the top surface of the film sheet or film portion of the support or supports located on said support or on said supports,
[00422] increase a temperature of the heating surface of the peripheral heater to a first temperature,
[00423] maintain the heating surface of the peripheral heater at least at the first temperature for a first distinct time interval,
[00424] reduce the temperature of the heating surface of the peripheral heater below said first temperature,
[00425] cause the heating surface of the internal heater to come into contact or be placed at a preset distance from the top surface of said film portion,
[00426] increase an internal heater heating surface temperature to a second temperature different from the first temperature, maintain the internal heater heating surface at least at the second temperature for a second distinct time interval, reduce the heating surface temperature of the internal heater below said second temperature,
[00427] - position the upper and lower tools in the said first operating condition,
[00428] - move the amount of supports with the film firmly fixed away from the packaging assembly.
[00429] A 131st aspect relates to a process according to the previous aspect wherein the heat sealing includes heating with the peripheral heater a peripheral band of said film portion or sheet of film and heating with the internal heater a zone internal part of the same film portion or film sheet located radially within the peripheral band,
[00430] wherein the film is not heat shrinkable and the first temperature is equal to the second temperature or wherein the film is heat shrinkable and the second temperature is lower than the first temperature.
[00431] A 132nd aspect concerns a process according to either of the two foregoing aspects wherein the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1, 5 seconds, and wherein the second distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds.
[00432] A 113th aspect concerns a process according to any of the three previous aspects in which during the heat sealing step the temperature rise of the heating surface of the internal heater until a second temperature starts after the increase in temperature of the peripheral heater to the first temperature, with the beginning of said second distinct time interval being delayed in relation to the beginning of said first time interval, optionally wherein the duration of said first distinct time interval is greater than the duration of said second distinct time interval.
[00433] A 134th aspect concerns a process according to any of the four previous aspects which comprises the steps of removing gas from the hermetically closed packaging chamber, up to a pressure comprised between 10 and 30 KPa (100 and 300 mbar) , optionally between 15 and 25 KPa (150 and 250 mbar), is reached inside said packaging chamber and then - while the film portion or film sheet is kept at a distance from the support nozzle - to inject a modified atmosphere gas in the packaging chamber, optionally where the injection of said gas stream to create a modified atmosphere takes place while a gas removal still takes place in order to shorten the time to create the modified atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS
[00434] The present invention will become clearer by reading the detailed description below, given by way of example and not limitation, to be read in reference to the attached drawings, in which:
[00435] - Figure 1 is a schematic side view product of an apparatus according to aspects of the invention in which a film is supplied from a roll of film and precut into film sheets on the outside with respect to an assembly packaging in which the precut film sheets are heat sealed to a backing, for example in the form of a tray;
[00436] - Figure 1A is a schematic side view product of an apparatus in accordance with aspects of the invention in which a film is supplied from a roll of film and fed into a packaging assembly where the film is heat sealed to a support, for example, in the form of a tray, and cut into separate sheets of film either immediately before heat sealing or after a film seal;
[00437] Figure 2 is a schematic front elevation view relating to a first embodiment of a packaging assembly, which may be present in a packaging apparatus of the type shown in Figure 1A, in accordance with aspects of the invention;
[00438] - Figures 3 to 11 are schematic front elevation views of the first embodiment of the packaging assembly of Figure 2 which represents consecutive phases of a packaging process. The apparatus and process according to these figures can - for example - be used to heat seal a lid on a tray either with a modified atmosphere in a tray or with normal atmosphere left in a tray;
[00439] - Figure 12 is a diagram that indicates, in a first geometric axis, the steps of a packaging process followed by the apparatus of Figure 1A when using the packaging assembly of Figures 2 to 11 and indicating, in a second axis geometric, the time in seconds, where in the diagram area the time intervals for each packaging process step are represented with gray modeled areas;
[00440] - Figure 13 is a schematic front elevation view relating to a second embodiment of a packaging assembly, which may be present in a packaging apparatus of the type shown in Figure 1A, in accordance with aspects of the invention;
[00441] - Figures 14 to 21 are schematic front elevation views of the second embodiment of the packaging assembly of Figure 13 which represents consecutive stages of a packaging process. The apparatus and process according to these figures can - for example - be used to heat seal a lid on a tray either with a modified atmosphere in a tray or with normal atmosphere left in a tray;
[00442] - Figure 22 is a diagram that indicates, in a first geometric axis, the steps of a packaging process followed by the apparatus of Figure 1A when using the packaging assembly of Figures 13 to 21 and indicating, in a second axis geometric, the time in seconds, where in the diagram area the time intervals for each packaging process step are represented with gray modeled areas;
[00443] - Figure 23 is a schematic front elevation view of a third embodiment of a packaging assembly, which may be present in a packaging apparatus of the type shown in Figure 1A, in accordance with aspects of the invention. In this Figure the packaging assembly includes two top tools that can be pivotally operated; alternatively it is possible to use a packaging assembly that has only a top tool and transfer device to move the precut film sheets in the packaging assembly as shown in Figure 1;
[00444] - Figures 24 to 30 are schematic front elevation views of the third embodiment of the packaging assembly of Figure 23 which represents consecutive stages of a packaging process. The apparatus and process according to these figures can - for example - be used to heat seal a lid on a tray either with a modified atmosphere in a tray or with normal atmosphere left in a tray;
[00445] - Figure 31 is a diagram that indicates, in a first geometric axis, the steps of a packaging process followed by the apparatus of Figure 1 when using the packaging assembly of Figures 23 to 30 and indicating, in a second axis geometric, the time in seconds, where in the diagram area the time intervals for each packaging process step are represented with gray modeled areas;
[00446] - Figure 32 is a perspective view of a first alternative heating head in accordance with aspects of the invention;
[00447] - Figure 32A represents a first option of the structure of a first conductive element, in an interrupted cross-section taken according to the section plane A-A of Figure 32;
[00448] - Figure 32B represents a second option of the structure of a first conductive element, in an interrupted cross-section taken according to the section plane A-A of Figure 32;
[00449] - Figure 33 is a perspective view of a second alternative heating head in accordance with aspects of the invention;
[00450] - Figure 33A represents a first option of the structure of a second conductive element, in an interrupted cross-section according to the cutting plane C-C of Figure 33;
[00451] - Figure 33B represents a second option of the structure of a second conductive element, in an interrupted cross-section according to the cutting plane C-C of Figure 33;
[00452] - Figure 34 is a perspective view of a third alternative heating head in accordance with aspects of the invention;
[00453] - Figure 34A represents a structure of a first conductive element, in an interrupted cross-section taken according to the section plane D-D of Figure 34;
[00454] - Figure 34B represents a structure of a second conductive element, in an interrupted cross-section taken according to the section plane E-E of Figure 34;
[00455] Note that Figures 32 to 34 (and thus the cross-sections of Figures 32A, 32B, 33A, 33B, 34A, 34B) are depicted upside down compared to the operating condition of the components shown therein.
[00456] - Figure 35 is a schematic view of a supply unit and a control device for controlling energy, in particular electrical energy, fed to the heater or heaters according to aspects of the invention;
[00457] - Figure 36 is a perspective view of a heating bar in accordance with aspects of the invention that may be used in the apparatus of Figures 37 and 38;
[00458] - Figure 37 is a schematic side view product of an additional apparatus in accordance with aspects of the invention; and
[00459] - Figure 38 represents a structure of a heater of the apparatus of Figure 37 in accordance with aspects of the invention. DEFINITIONS AND CONVENTIONS
[00460] It should be noted that, in the present detailed description, the corresponding parts shown in the various figures are indicated with the same reference numeral throughout all figures. Note that the figures are not to scale and thus the parts and components shown in the figures are schematic representations.
[00461] Although certain aspects of the invention may find application to packaging a product in a packaging only formed from one or more plastic films, the following description will mainly refer to the packaging of a product positioned on a support 4 to which a plastic film it is heat sealed. Note that the product can be a food product or not.
[00462] As used herein, support 4 means either a substantially flat element on which a product is placed, or a container of the type having a base wall 4a, a side wall 4b and a top edge 4c that emerges radially from the sidewall 4b, the container which defines a volume in which the product is positioned.
[00463] The tray or supports 4 can have a rectangular shape or any other suitable shape, such as round, square, elliptical etcetera, and can be formed or while the packaging process takes place, for example, in a thermoforming station of the packaging apparatus, or they may be previously manufactured and then fed into the packaging apparatus.
[00464] Also note that the aspects of the invention described and claimed in this document are applicable to an apparatus or a process that uses pre-made trays and to so-called "thermoforming processes or machines", i.e., to apparatus and processes where the backing or tray is thermoformed in-line starting with a plastic roll. CARBON STRUCTURE
[00465] As used herein, a carbon structure refers to a structure that has electrically conductive capacity.
[00466] The electrically conductive carbon structure includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[00467] - a graphite structure,
[00468] - a single-layer or multi-layer graphene structure,
[00469] - a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00470] It should be noted that the electrically conductive elements (first and/or second) described in this document may be formed by an electrically conductive carbon structure completely formed in one or more of the carbon allotropes disclosed above.
[00471] For example, the first and/or second electrically conductive element may be exclusively formed from graphite, or may be exclusively formed from a single layer of graphene, or may be exclusively formed from a plurality of mutually overlapping graphene layers , or it can be uniquely formed in a carbon nanotube fullerene structure, or it can be formed in a carbon nanofiber fullerene structure, or it can be uniquely formed through a combination of one or more of the mentioned carbon allotropes.
[00472] According to a further variant the electrically conductive carbon structure may comprise a structure formed by carbon filaments that are in contact adjacent to each other to form a conductive body or by carbon filaments embedded in a matrix of plastic resin: in the latter case the carbon filaments can be placed adjacently and electrically connected to each other in prescribed sections such as at their ends.
[00473] Depending on its specific structure and the technology available to the manufacturer, the carbon structure can be applied to a support in order to form a heater in several ways: for example, a strip or a layer or a filament structure of carbon can be glued to a support; or a strip or layer or filament can be formed from particles deposited on a backing (eg, sprayed or painted), or the carbon structure in any of the above structures can be embedded in a resin matrix during fabrication ( eg embedded in a reinforced resin matrix). THE TRAYS
[00474] When the support takes the form of a tray, it can be made of a single layer or, preferably, of a multilayer polymeric material.
[00475] In case of a single layer material suitable polymers are, for example, polystyrene, polypropylene, polyesters, high density polyethylene, poly(lactic acid), PVC and the like, whether foamed or solid.
[00476] Preferably the tray 4 is provided with gas barrier properties. As used herein, this term refers to a film or sheet of material that has an oxygen transmission rate of less than 200 cm3 /m2-day-bar, less than 150 cm3 /m2-day-bar, less than 100 cm3 /m2-day-bar as measured in accordance with ASTM D-3985 at 23°C and 0% relative humidity.
[00477] Suitable materials for gas barrier monolayer thermoplastic trays 4 are, for example, polyesters, polyamides and the like.
[00478] If tray 4 is made of a multilayer material, suitable polymers are, for example, ethylene homo- and copolymers, propylene homo- and copolymers, polyamides, polystyrene, polyesters, poly(lactic acid), PVC and the like. Some of the multilayer material can be solid and some can be foamed.
[00479] For example, tray 4 may comprise at least one layer of a foamed polymeric material chosen from the group consisting of polystyrene, polypropylene, polyesters and the like.
[00480] The multilayer material can be produced either by co-extrusion of all layers using co-extrusion techniques or by hot rolling or gluing, for example, a solid or foamed rigid substrate with a thin film, usually called "coating".
[00481] The thin film can be laminated either on the side of tray 4 in contact with product P or on the side facing away from product P or on both sides. In the latter case the films laminated on both sides of tray 4 can be the same or different. A layer of an oxygen barrier material, eg a copolymer (ethylene-co-vinyl alcohol), is optionally present to increase the shelf life of the packaged product P.
[00482] The gas barrier polymers that can be employed for the gas barrier layer are PVDC, EVOH, polyamides, polyesters and blends thereof. The thickness of the gas barrier layer will be defined in order to provide the tray with an adequate oxygen transmission rate for the specific packaged product.
[00483] The tray may also comprise a heat sealable layer. Generally, the heat sealable layer will be selected from polyolefins such as ethylene homo- or copolymers, propylene homo- or copolymers, ethylene/vinyl acetate copolymers, ionomers, and homo- and co-polyesters, for example, PETG, a glycol-modified polyethylene terephthalate.
[00484] Additional layers, such as adhesive layers, to better adhere the gas barrier layer to adjacent layers, may be present in the gas barrier material for the tray and are preferably present depending in particular on the specific resins used for the layer of gas barrier.
[00485] In case of a multilayer material used in order to form tray 4, part of this structure may be foamed and part may be unfoamed. For example, tray 4 may comprise (from the outermost layer to the innermost food contact layer) one or more structural layers, typically of a material such as foamed polystyrene, foamed polyester or foamed polypropylene, or a molded sheet of, for example, polypropylene, polystyrene, poly(vinyl chloride), polyester or cardboard; a gas barrier layer and a heat sealable layer.
[00486] Tray 4 can be obtained from a sheet of foamed polymeric material having a film comprising at least one oxygen barrier layer and at least one surface sealing layer laminated on the side facing the packaged product, of way the surface sealing layer of the film is the food contact layer of the tray. A second film, whether barrier or non-barrier, can be laminated to the outer surface of the tray.
[00487] Specific 4 Tray formulations are used for food products that require heating in a microwave or conventional oven prior to consumption. The surface of the container in contact with the product, for example the surface involved in forming the seal with the cap film, comprises a polyester resin. For example, the container can be made of cardboard coated with a polyester or it can be made entirely of a polyester resin. Examples of suitable containers for the package of the invention are CPET, APET or APET/CPET containers. Such a container can be either foamed or unfoamed.
[00488] Trays 4 used for film applications or covers that contain foamed parts, have a total thickness less than 8 mm and, for example, can be between 0.5 mm and 7.0 mm and more often between 1 .0mm and 6.0mm.
[00489] In the case of a rigid tray that does not contain foamed parts, the total thickness of the single-layer or multi-layer thermoplastic material is preferably less than 2 mm, and, for example, may be between 0.1 mm and 1.2 mm and more often between 0.2 mm and 1.0 mm.
[00490] The supports can be made with the same materials and structure revealed for the trays. THE FILM OR FILM MATERIAL APPLICABLE TO TRAYS OR SUPPORTS
[00491] The film or film material 18 is applied to tray 4 to form a cover over the tray (for example, for MAP - modified atmosphere packaging) or a film associated with the tray or support and which is in contiguity with the contour of the product.
[00492] The film for film applications may be made of a flexible multilayer material comprising at least an external heat-sealable first layer, an optional gas barrier layer and an external heat resistant second layer. The outer heat-sealable layer may comprise a polymer capable of welding to the inner surface of the supports carrying the products to be packaged, such as, for example, ethylene homo- or copolymers, similar to LDPE, ethylene/alpha-olefin copolymers , ethylene/acrylic acid copolymers, ethylene/methacrylic acid copolymers, and ethylene/vinyl acetate copolymers, ionomers, co-polyesters, e.g. PETG. The optional gas barrier layer preferably comprises oxygen impermeable resins similar to PVDC, EVOH, polyamides and blends of EVOH and polyamides. The external heat resistant layer can be made of ethylene homo- or copolymers, ethylene/cyclic olefin copolymers, such as ethylene/norbornene copolymers, propylene homo- or copolymers, ionomers, (co)polyesters, (co)polyamides . The film may also comprise other layers such as adhesive layers or bulk layers to increase the film's thickness and improve its abuse and deep stamping properties. Particularly used bulking layers are ionomers, ethylene/vinyl acetate copolymers, polyamides and polyesters. In all film layers, the polymer components can contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or one of the outer layers, while some others are preferably added to inner layers. These additives include slip and anti-blocking agents such as talc, waxes, silica and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, crosslink inhibitors, crosslink enhancers, UV absorbers, odor absorbers, oxygen scavengers , bactericides, antistatic agents and similar additives known to those skilled in the packaging film art.
[00493] One or more layers of the film can be crosslinked to improve the strength of the film and/or its heat resistance. Crosslinking can be achieved using chemical additives or subjecting the film layers to an energetic radiation treatment. Film packaging films are typically manufactured in order to show little shrinkage when heated during the packaging cycle. These films typically shrink less than 15% at 160°C, more often less than 10%, even more often less than 8% in both the longitudinal and transverse directions (ASTM D2732). Films typically have a thickness of between 20 microns and 200 microns, more often between 40 and 180 microns, and even more often between 50 microns and 150 microns.
[00494] Film packages are usually "easy to open", for example they are easily opened by manually pulling the two nets apart, usually starting from a point similar to a corner of the package where the net superior was not purposely barred from support. In order to achieve this feature, either the film or tray can be provided with a suitable composition, which allows for easy opening of the package, as known in the art. Typically, the sealing composition and/or the composition of the adjacent layer of the tray and/or the film are adjusted in order to achieve the easy-open feature.
[00495] Several mechanisms can occur while opening an easy-to-open package.
[00496] In the first one ("peelable easy opening") the package is opened separating the film and tray at the sealing interface.
[00497] In the third mechanism ("adhesive failure") the opening of the package is achieved through an initial break through the thickness of one of the sealing layers followed by the delamination of that layer from the backing or underlying film.
[00498] The third system is based on the "cohesive failure" mechanism: the easy-open feature is achieved through the internal rupture of a sealing layer which, during the opening of the package, breaks along a plane parallel to itself layer.
[00499] Specific blends are known in the art in order to obtain such opening mechanisms, ensure peeling of the film from the tray surface, such as the same as described in patent document no EP1084186.
[00500] On the other hand, if film 18 is used to create a lid on tray 4, the film material can be obtained by lamination or co-extrusion processes. Lid films can have a symmetrical or asymmetrical structure and can be monolayer or multilayer.
[00501] Multilayer films have at least 2, more often at least 5, even more often at least 7 layers. The total film thickness can often vary from 3 to 100 microns, in particular from 5 to 50 microns, even more than 10 to 30 microns.
[00502] Films can be optionally crosslinked. Crosslinking can be accomplished through irradiation with high energy electrons at a suitable dosage level as known in the art. The cover films described above can be heat shrinkable or heat-set. Heat shrinkable films typically show a free shrinkage value at 120°C measured in accordance with ASTM D2732 in the range of 2 to 80%, more often 5 to 60%, even more often 10 to 40% both in longitudinal and transverse direction. Hot-set films typically have free shrinkage values less than 10% at 120°C, preferably less than 5% in both the longitudinal and transverse directions (ASTM D 2732). Lid films typically comprise at least one heat-sealable layer and an outer film layer, which is generally made of heat-resistant polymers or polyolefin. The sealing layer typically comprises a heat sealable polyolefin which in turn comprises a single polyolefin or a blend of two or more polyolefins such as polyethylene or polypropylene or a blend thereof. The sealing layer may additionally be provided with anti-fog properties by incorporating one or more anti-fog additives into its composition or by coating or spraying one or more anti-fog additives onto the surface of the sealing layer by a technical means well known in the art . The sealing layer can additionally comprise one or more plasticizers. The film layer can comprise polyesters, polyamides or polyolefin. In some structures, a blend of polyamide and polyester can be advantageously used for the film layer. In some cases, cover films comprise a barrier layer. Barrier films typically have an OTR (rated at 23°C and 0% RH according to ASTM D-3985) below 100 cm3/(m2^dia^atm) and more often below 80 cm3/(m2^ dia^atm). The barrier layer is usually made of a thermoplastic resin selected from a hydrolyzed or saponified ethylene-vinyl acetate (EVOH) copolymer product, an amorphous polyamide and a vinyl-vinylidene chloride and their addition blends. Some materials comprise an EVOH barrier layer sandwiched between two polyamide layers. The film layer typically comprises polyesters, polyamides or polyolefin.
[00503] In some packaging applications, cover films do not comprise any barrier layer. Such films typically comprise one or more polyolefins as defined herein.
Non-barrier films typically have an OTR (rated at 23°C and 0% RH according to ASTM D-3985) of 100 cm3/(mzdia^atm) to 10,000 cm3/(mzdia^atm), more typically up to 6,000 cm3/(mzdia^atm).
[00505] The peculiar compositions based on polyester are the same as those used for ready meal package tray covers. For such films, polyester resins can constitute at least 50%, 60%, 70%, 80%, 90% by weight of the film. These films are typically used in combination with polyester based backings.
[00506] For example, the container can be made of a cardboard coated with a polyester or it can be made entirely of a polyester resin. Examples of suitable containers for the package are CPET, APET or APET/CPET containers, whether foamed or non-foamed.
[00507] Typically, biaxially oriented PET are used as the cover film due to their high thermal stability at standard food heating/baking temperatures. Often biaxially oriented polyester films are heat-set, for example, not heat shrinkable. To improve the heat sealability of the PET lid film to the container a heat sealable layer of a lower melt material is normally provided in the film. The heat sealable layer can be co-extruded with the PET base layer (as disclosed in patent document EP-A-1,529,797 and WO2007/093495) or it can be solvent - or extrusion coated onto the base film (as disclosed in patent document no. US 2,762,720 and EP-A-1,252,008).
[00508] Particularly in the case of fresh red meat packages, a double lid film comprising an oxygen permeable inner lid film and an oxygen impermeable outer lid film are advantageously used. The combination of these two films significantly prevents meat discoloration also when the packed meat extends upstream in relation to the height of the tray walls, which is the most critical situation in barrier packing of fresh meat.
Such films are described, for example, in EP1848635 and EP0690012, the disclosures of which are incorporated herein by reference.
[00510] The cover film can be monolayer. The typical composition of monolayer films comprises polyesters as defined herein and blends thereof or polyolefins as defined herein and blends thereof.
[00511] In all film layers described herein, the polymer components may contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or one of the outer layers, while some others are preferably added in inner layers. Such additives include slip and anti-blocking agents such as talc, waxes, silica, and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, crosslink inhibitors, crosslink enhancers, UV absorbers, odor absorbers, odor removers, oxygen, bactericides, antistatic agents, anti-mist agents or compositions, and similar additives known to those skilled in the art of packaging films.
[00512] Films suitable for a lid application can be advantageously perforated in order to allow the packaged food to breathe.
[00513] These films can be perforated using different technologies available in the technique, through laser or mechanical means such as rollers equipped with many needles.
[00514] The amount of perforations per unit area of the film and their dimensions affect the gas permeability of the film.
[00515] Microperforated films are normally characterized by the OTR value (assessed at 23°C and 0% R.H. according to ASTM D3985) of 2,500 cm3/(mzdia^atm) to 1,000,000 cm3/(mzdia^atm).
[00516] Macroperforated films are usually characterized by OTR (rated at 23°C and 0% R.H. according to ASTM D-3985) greater than 1,000,000 cm3/(m2^dia^atm).
[00517] Furthermore, the films described herein for cap applications can be formulated to provide a peelable or strong seal over the backing. A method of measuring the strength of a peelable seal, referred to herein as "peel strength" is described in ASTM F-88-00. Acceptable peel strength values are in the range of 100g/25mm to 850g/25mm, 150g/25mm to 800g/25mm, 200g/25mm to 700g/25mm.
[00518] The desired sealing strength is achieved by specifically designing the tray and lid formulations.
[00519] In general, one or more layers of cover film may be printed in order to provide useful information to the consumer, a pleasing image and/or a trademark or other advertising information to improve the retail sale of the product packaged.
[00520] The film can be printed by any suitable method, such as the rotary screen, gravure or flexographic techniques as known in the art. DEFINITIONS AND CONVERSIONS CONCERNING MATERIALS
[00521] PVDC is any vinylidene chloride copolymer in which a greater amount of the copolymer comprises vinylidene chloride and a smaller amount of the copolymer comprises one or more unsaturated monomers copolymerizable therewith, typically vinyl chloride, and alkyl acrylates or methacrylates (eg methyl acrylate or methacrylate) and their blends in different proportions. Generally a PVDC barrier layer will contain plasticizers and/or stabilizers as known in the art.
[00522] As used herein, the term EVOH includes saponified or hydrolyzed ethylene-vinyl acetate copolymers, and refers to ethylene/vinyl alcohol copolymers having an ethylene comonomer content preferably from about 28 to about 48 mol%, more preferably from about 32 to about 44 mol% ethylene, and even more preferably, a degree of saponification of at least 85%, preferably at least 90%.
[00523] The term "polyamides" as used herein is intended to refer to both homopolyamides and copolyamides or terpolyamides. That term specifically includes aliphatic polyamides or copolyamides, e.g., polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 69, polyamide 610, polyamide 612, copolyamide 6/9, copolyamide 6/10, copolyamide 6/12, copolyamide 6/66, copolyamide 6/69, aromatic and partially aromatic polyamides or copolyamides, such as polyamide 6I, polyamide 6I/6T, polyamide MXD6, polyamide MXD6/MXDI, and blends thereof.
[00524] As used herein, the term "copolymer" refers to a polymer derived from two or more types of monomers, and includes terpolymers. Ethylene homopolymers include high density polyethylene (HDPE) and low density polyethylene (LDPE). Ethylene copolymers include ethylene/alpha-olefin copolymers and ethylene/unsaturated ester copolymers. Ethylene/alpha-olefin copolymers generally include copolymers of ethylene and one or more comonomers selected from alpha-olefins having 3 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 1- octene, 4-methyl-1-pentene and the like.
[00525] Ethylene/alpha-olefin copolymers generally have a density in the range of about 0.86 to about 0.94 g/cm3. The term linear low density polyethylene (LLDPE) is generally understood to include the same group of ethylene/alpha-olefin copolymers that fall within the density range of about 0.915 to about 0.94 g/cm3 and particularly from about 0.915 to about 0.925 g/cm3. Sometimes a linear polyethylene in the density range of about 0.926 to about 0.94 g/cm3 is called linear medium density polyethylene (LMDPE). Lower density ethylene/alpha-olefin copolymers can be called very low density polyethylene (VLDPE) and ultra low density polyethylene (ULDPE). Ethylene/alpha-olefin copolymers can be obtained through either heterogeneous or homogeneous polymerization processes.
[00526] Another useful ethylene copolymer is an ethylene/unsaturated ester copolymer, which is the copolymer of ethylene and one or more unsaturated ester monomers. Useful unsaturated esters include vinyl esters of aliphatic carboxylic acids, where the esters have 4 to 12 carbon atoms, such as vinyl acetate, and alkyl esters of acrylic or methacrylic acid, where the esters have 4 to 12 carbon atoms. carbon.
[00527] Ionomers are copolymers of an ethylene and an unsaturated monocarboxylic acid which have the carboxylic acid neutralized by a metal ion such as zinc or, preferably, sodium.
[00528] Useful propylene copolymers include propylene/ethylene copolymers, which are the copolymers of propylene and ethylene that have a majority weight percent content of propylene, and propylene/ethylene/butene terpolymers, which are the copolymers of propylene, ethylene and 1-butene.
As used herein, the term "polyolefin" refers to any polymerized olefin, which may be linear, branched, cyclic, aliphatic, aromatic, substituted or unsubstituted. More specifically, included in the term polyolefin are olefin homopolymers, olefin copolymers, copolymers of an olefin and non-olefinic comonomer copolymerizable with the olefin, such as vinyl monomers, modified polymers thereof, and the like. Specific examples include polyethylene homopolymer, polypropylene homopolymer, polybutene homopolymer, ethylene-alpha-olefin copolymer, propylene-alpha-olefin copolymer, butene-alpha-olefin copolymer, ethylene-olefin copolymer. unsaturated ester, unsaturated ethylene-acid copolymer, (eg ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer and ethylene-acid copolymer methacrylic), ethylene-vinyl acetate copolymer, ionomer resin, polymethylpentene, etc.
[00530] The term "polyester" is used herein to refer to both homo-polyesters and co-polyesters, wherein homo-polyesters are defined as polymers obtained from the condensation of a dicarboxylic acid with a diol and co-polyesters are defined as polymers obtained from the condensation of one or more dicarboxylic acids with one or more diols. Suitable polyester resins are, for example, polyesters of ethylene glycol and terephthalic acid, for example, poly(ethylene terephthalate) (PET). Preference is given to polyesters which contain ethylene units and comprise, based on the dicarboxylate units, at least 90 mol%, more preferably at least 95 mol%, terephthalate units. The remaining monomer units are selected from other dicarboxylic acids or diols. Other suitable aromatic dicarboxylic acids are preferably isophthalic acid, phthalic acid, 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid. Among cycloaliphatic dicarboxylic acids, mention should be made of cyclohexanedicarboxylic acids (in particular, cyclohexane-1,4-dicarboxylic acid). Among the aliphatic dicarboxylic acids, (C3-C19)alkanedioic acids are particularly suitable, in particular succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable diols are, for example, aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 2,2-dimethyl -1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and aliphatic cyclodiols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexane diol, optionally heteroatom containing diols having one or more rings.
Copolyester resins derived from one or more dicarboxylic acid (or dicarboxylic acids) or their lower alkyl diesters (up to 14 carbon atoms) with one or more glycol (or glycols), particularly an aliphatic or cycloaliphatic glycol can also be used as the polyester resins for the base film. Suitable dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, or 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as succinic acid, sebacic acid, acid adipic, azelaic acid, suberic acid or pimelic acid. Suitable glycol (or suitable glycols) include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 2.2 -dimethyl-1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and aliphatic cyclodiols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexane diol. Examples of such copolyesters are (i) copolyesters of azelaic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; (ii) adipic acid and terephthalic acid copolyesters with an aliphatic glycol, preferably ethylene glycol; and (iii) copolyesters of sebacic acid and terephthalic acid with an aliphatic glycol, preferably butylene glycol; (iv) co-polyesters of ethylene glycol, terephthalic acid and isophthalic acid. Suitable amorphous copolyesters are those derived from an aliphatic diol and a cycloaliphatic diol with one or more dicarboxylic acid (or dicarboxylic acids), preferably an aromatic dicarboxylic acid. Typical amorphous copolyesters include co-polyesters of terephthalic acid with an aliphatic diol and a cycloaliphatic diol, especially ethylene glycol and 1,4-cyclohexanedimethanol. DETAILED DESCRIPTION OF THE FIRST MODE OF THE APPLIANCE 1
[00532] Reference is made to Figures 1A and 2 to 12. In particular, Figure 1A shows an apparatus 1 for packaging a product P disposed in a tray 4. The apparatus 1 is adapted for packaging with modified atmosphere, wherein a plastic film 18 is applied to the top edge 4c of a tray 4 after a modified gas atmosphere has been created within the support 4, and/or for vacuum film packaging of the product P, in which a thin film of material plastic is stamped deep into the product and immediately adheres to a top edge and the inner surface of the support as well as the product surface and thus leaves a minimal amount of air, if any, in the packages. Apparatus 1 can also be used if the film sheet is applied to a tray or a support and neither a vacuum nor a modified atmosphere is created.
[00533] The apparatus 1 comprises a frame 2, a transport assembly 3 for moving the tray 4, a film drive assembly 5 and a packaging assembly 8.
[00534] The tray 4 shown in the closed figures has a base wall 4a, a side wall 4b that emerges from the base wall and delimits a space in which a product P can be housed, and a top edge 4c that projects radially of the sidewall 4b: In the example shown the top edge 4c has a flat horizontal portion that defines an optimal sealing surface for firmly attaching a plastic film.
[00535] The frame 2 defines a base body of the apparatus 1 and serves to carry and support various parts of the apparatus 1 as described in this document.
[00536] The transport assembly 3 comprises a displacement plane 20 (which can be a physical plane in which the trays or support are at rest and slide or an ideal plane along which the trays are guided, for example, by means of rails or guides). The plane 20 is defined in a top area of the frame and a conveyor 46 is arranged in correspondence with the sliding plane 20. In the example shown, the conveyor assembly 3 is carried by the frame 2, for example, fixed to it in such a way that the sliding plane 20 is substantially horizontal and the conveyor 46 moves the trays or supports 4 according to the horizontal direction indicated by arrow A1 shown in Figure 1. The transport assembly 3 arranged in frame 2 is configured to move the support or tray 4 along a predefined path from a loading station, where the supports or trays 4 that may already be filled with the respective product (or the respective products) P are positioned, in the packaging assembly 8 in that a film 18 is firmly attached to each support or tray 4, as will be explained below in detail herein. Conveyor 46 moves the trays, for example, a preset number of trays at a time, within the packaging assembly 8 into an appropriate position to receive the film 18. For example, a control unit 100 (which will be further described hereinafter document) can control conveyor 46 to move a preset amount of trays or supports 4 at a time from a region outside the packaging assembly to a region within the packaging assembly where the tray or trays are in vertical alignment with the respective portions of film 18a of film 18. The conveyor may, for example, include a first transfer device 46a (such as the belt shown in Figure 1A) configured to bring the trays in close proximity to the packaging assembly and an adapted second transfer device 46b to take one or more of said trays and take them to the packing station. The second transfer device may, for example, include arms which act on the sides of the trays or holders such as to pick up the holders of the first transfer device, bring them to the packaging station and then return to the first transfer device. to pick up a new set of trays or supports 4. Alternatively, conveyor 46 may include pushers (e.g. in the form of bars extending transversely to said direction A1) which act on the trays and push the trays into the assembly of packaging. The pushers can be moved by chains or belts and can be moved in the packing assembly to properly position numerous trays, and then retracted from the packing assembly once the trays have reached their proper positions within the last. According to a further alternative, the conveyor 46 may include housings (e.g. in the form of plates provided with cavities for receiving numerous trays) which are moved along said direction A1 and which move within the packaging station together with the supports or trays 4: according to this last alternative the accommodations are properly shaped in order to be housed inside the packaging station during the application of the film in tray 4.
[00537] Note that P products can be positioned on the support or tray 4 either upstream of the charging station or at any location between the charging station and the packing assembly 8. The transport assembly 3 additionally comprises a motor 9, for example, a stepping motor unit, for operating the conveyor belt 46 in a step-by-step motion.
[00538] The film drive assembly 5 may comprise a roll of film 10 that supplies the continuous film 18. The film drive assembly 5 may additionally comprise an arm 11 shown in broken lines in Figure 1A) attached to frame 2 and suitable for supporting roll 10. Film 18 of roll of film 10 can be made as developed above depending on specific need. Note that the continuous film 18 can be fed from the film drive assembly 5 into the appropriate position within the packaging assembly 8 by any known means, for example with the use of drive rollers or drive mechanisms that act upstream and /or downstream of the packaging assembly, or with the use of transport devices acting on the longitudinal edges of the film 18, or combinations of the above means or any other suitable device.
[00539] The apparatus packaging assembly 8 is configured to securely attach the film sheets 18 to said supports 4; the packaging assembly 8 includes a lower tool 22 and an upper tool 21. As best seen from Figure 2, the lower tool 22 has a number of inner walls 23 defining a preset amount of holders 23b. In one embodiment the lower tool 22 is provided with multiple supports 23b each hosting a corresponding support 4; the upper tool 21 is configured to retain an appropriate film portion 18a of the film 18 enough to close the trays positioned on said support or on said supports 23b.
[00540] Each of the supports 23b is configured to receive a support 4., for example, in the example of Figures 2 to 11 the support 23b is peripherally delimited by the inner wall 23 and the support or tray 4 is received in the support 23b such that the top edge 4c can rest on the end surface 23a of the inner wall 23. The upper tool 21 faces the lower tool 22 and is configured to retain a film portion 18a of the film 18 just above the respective tray 4. As shown in Figures 2 to 11 the upper and lower tools 21, 22 cooperate in order to define a packaging chamber 24: in a first operating condition of the packaging assembly 8 - shown, for example, in Figures 2 and 3 - the upper and lower tools 21 and 22 are spaced apart and the packaging chamber 24 is open, which thereby allows the film 18 to move within the packaging chamber 24 and a film portion 18a of the film 18 soon above the respective tray 4. In a second operating condition of the packaging assembly 8 the packaging chamber 24 is closed, in certain cases hermetically closed, with respect to an atmosphere outside the apparatus 1, in such a way that the film portion 18a can be heat sealed at least to the 4c top edge of tray 4.
[00541] Note that hermetically closed means that the packaging chamber 24 cannot freely communicate with the atmosphere outside the same chamber since a gas can be supplied or removed from the chamber only through the discharge or supply channels under the control of the device 1.
[00542] In order to open and close the packaging chamber, the apparatus 1 has a main actuator 33 (see Figure 1A) active in at least one of said upper and lower tool 21, 22 under the control of the control device 100; in practice the main actuator 33 may include a piston (the piston may be replaced by any other type of electric, pneumatic or hydraulic linear actuator) configured to raise and lower one or both of the tools 22 along a direction transverse to said horizontal direction A1 between said first operating condition (Figure 3), wherein the upper tool 21 is spaced from the lower tool 22 and said packaging chamber 24 is opened to receive one or more of said film portions 18a, and said second operating condition (Figure 4), in which a closure surface 34 of the upper tool 21 fits tightly against a closure surface 35 of the lower tool 22 (or against a mating surface of an insert member 400) in order to close hermetically sealing said packaging chamber 24 to an atmosphere outside the apparatus; on said closure surfaces 34 and 35 a gasket or other element to facilitate a firm closure against gas leakage can be positioned.
[00543] The upper tool 21 comprises an internal heater 200 loaded by the upper tool in such a way as to face the support 23b and which has a heating surface 201 configured to heat at least a part of said portion of film 18a, and a Peripheral heater 202 carried by the upper tool 21 such that it faces the same support 23b and is positioned radially outwardly with respect to the internal heater 201. The peripheral heater 202 basically surrounds the internal heater 200 and is aligned with the surface 23a of The way that a heating surface 203 of the peripheral heater 201 is capable - when brought into contact with the film 18 - of heat sealing the latter to the tray 4: in particular, the upper tool 21 is configured to drive the heating surface 203 of the peripheral heater 202 in correspondence with the edge 4c of the tray 4 located on the support 23b, so that at least one peripheral region 18b of the said portion of film 18a overlying the edge 4c can be hot-bonded to the latter.
[00544] As can be seen from Figure 2, the heating surface 203 of said peripheral heater 202 has an annular shape. Note that an annular shape means a closed shape that can be circular, elliptical, rectangular, or any other closed shape. In the specific embodiment disclosed the closed shape of the heating surface 203 copies the shape of the top surface of the rim 4c of the tray 4 or copies the shape of the top surface 23a of the inner wall 23.
[00545] As shown in Figure 2, the heating surface 203 of the peripheral heater 202 and surrounds - and in particular completely circles - the heating surface 201 of the internal heater 200, such that when the upper and lower tools are in said In the second operating position, peripheral heater 202 is configured to heat a peripheral region or a strip 18b of said film portion 18a while internal heater 200 is configured to heat at least a portion of an internal zone of the same located film portion 18a radially within the peripheral region 18b.
[00546] In greater detail and again with reference to Figure 2, both the heating surface of the peripheral heater and the heating surface of the internal heater can take a flat shape in order to perfectly adjoin the shape of the top edge 4c from the tray. Note that when the first and second tools 21 and 22 (upper and lower tools) are in the second operating position, an actuator such as auxiliary actuator 312 carried by upper tool 21 and controlled by control device 100 can be operated to bring the heating surface against said peripheral band of the film portion 18a, the top edge 4c being pressed between said peripheral band of the film portion 18a and the top surface 23a.
[00547] In the mode shown in Figure 2, when the upper and lower tools are in said second operating position, the heating surface 203 of the peripheral heater 202 is coplanar to the heating surface 201 of the internal heater 200, such that both the surfaces come into contact with the respective parts of the film portion 18a at the same time.
[00548] Alternatively, the heating surface 201 of the internal heater 200 may be slightly indented (for example, from 1 to 20 mm) relative to the heating surface 203 of the peripheral heater 202, such that when the heating surface of the peripheral heater is in contact with the top surface of the film portion, the heating surface of the inner heater is spaced a preset distance away from the top surface of the same film portion.
[00549] Now, referring to Figures 32 and 33 showing heating heads usable as part of the upper tool 21 of the apparatus according to the first embodiment, it is shown that the upper tool 21 may include a heating head with an internal heater 200 and a peripheral heater 202 wherein the heating surface 201 of the inner heater 200 is located at a radial distance 'd' from the heating surface 203 of the peripheral heater 202 and extends in an area surrounded by the heating surface of the peripheral heater 202 : in other words the heating surface of the internal heater 200 is not in contact with the heating surface of the peripheral heater 202. The two heating surfaces and the peripheral heater and the internal heater are kept separate and thermally insulated from each other.
[00550] In Figure 33 it is shown that the heating surface 201 of the internal heater 200 may be an annular shaped heating surface, while in Figure 34 it is shown that the heating surface 201 of the internal heater may be a continuous heating surface bounded by a single closed contour line: in the example of Figure 34 the heating surface 201 is rectangular, but obviously it can have any suitable shape (which typically depends on the shape of the tray) such as discoidal or polygonal or circular, or elliptical or polygonal with rounded corners, etc. In the case of Figure 34, however, the continuous heating surface is designed to occupy substantially all or most (greater than 50%, preferably greater than 70%) of the area ideal flat surrounded by the heating surface of the peripheral heater. Finally, in the example of Figure 32 the heating surface 201 of the internal heater 200 is a heating surface which includes a plurality of spaced parallel strips 204 connected at ends thereof, e.g. through transverse strips or through transverse connecting portions 205 so as to define a meander shape.
[00551] In a further aspect, the peripheral heater 202 comprises a first electrically conductive element that extends along the heating surface of the peripheral heater: the first electrically conductive element is shaped as the heating surface of the peripheral heater and transports heat to the heating surface 203 by virtue of the temperature increase caused in the first electrically conductive element caused by the passage of electric current. Thus the first electrically conductive element is an annular element, optionally an electrically conductive flat annular element. The first electrically conductive element can be housed within the peripheral heater body or can basically form the peripheral heater itself.
[00552] In turn, the internal heater 200 comprises a second electrically conductive element that extends along the heating surface of the internal heater: the second electrically conductive element is shaped as the heating surface of the internal heater and transports heat to the heating surface 203 by virtue of the temperature increase caused in the second electrically conductive element caused by the passage of electric current. The second electrically conductive element can be housed within the internal heater body or can basically form the internal heater itself. The second conductive element can therefore be:
[00553] an electrically conductive annular element, optionally an electrically conductive annular flat element,
[00554] an electrically conductive continuous plate,
[00555] an electrically conductive meander element, optionally an electrically conductive flat meander element.
[00556] In further structural details, the first and second electrically conductive elements can take several alternative designs.
[00557] In a first option (Figure 32A), the first electrically conductive element comprises:
[00558] - a support substrate 206 carried by the superior tool 21 or integrated thereto,
[00559] - a conductive strip of carbon or metallic structure207 (for example, in the form of a plurality of superimposed graphene layers or one of the forms described above) attached to the supporting substrate, and
[00560] - an optional protective layer 208 covering the conductive strip of carbon or metallic structure and defining the heating surface of the peripheral heater,
[00561] In a second option (Figure 32B), the first electrically conductive element comprises:
[00562] - a support substrate 206 carried by the superior tool or integrated with it,
[00563] - an insulation layer 209 in contact with the supporting substrate,
[00564] - a conductive layer 207 in the form of a metal-glass mixture that defines a conductive strip in contact with the insulating layer, and
[00565] - a protective layer 208 covering the conductive layer defining the heating surface;
[00566] Note that the first electrically conductive element of the heating head shown in Figure 33 may have the structure described above for the first electrically conductive element of the heating head shown in Figure 32 and so Figures 32A and 32B may also reflect the structure of the cross-section taken along plane BB of Figure 33 in correspondence with the peripheral heater.
[00567] As for the second electrically conductive element, it can comprise in a first option (Figure 33A):
[00568] - a support substrate 210 carried by the superior tool 21 or integrated thereto,
[00569] - a conductive structure 211 of carbon or metallic structure (for example, in the form of a plurality of overlapping graphene layers or in one of the forms described above) selected from the group of: a strip, a plate and a meander, being that the carbon or metallic structure is fixed to the supporting substrate, and
[00570] - an optional protective layer 212 covering the carbon or metallic conductive structure and defining the heating surface of the peripheral heater.
[00571] Alternatively, according to a second option (Figure 33B), the second electrically conductive element may comprise:
[00572] - a supporting substrate 210 carried by the upper tool or integrated thereto, an insulating layer 213 in contact with the supporting substrate, a conductive structure 211 in the form of a metal-glass blend layer taking the shape of a strip, a plate or a meander, said conductive structure 211 being in contact with the insulating layer, and a protective layer 212 covering the conductive layer and defining the heating surface.
[00573] According to an alternative, which is shown in Figures 34, 34A and 34B, the first electrically conductive element comprises an electrically conductive layer in the form of a carbon structure 207, a structural support substrate 206 that carries the carbon structure and at least one protective layer 208 covering the carbon structure on an opposite side of the structural substrate. The substrate can be attached to the top tool or to a heating head associated with the top tool.
[00574] The carbon structure may optionally be sandwiched between two opposing protective layers 208, wherein the protective layer opposite the structural substrate defines the heating surface of said peripheral heater.
[00575] In particular, the carbon structure of the first electrically conductive element includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[00576] - a graphite structure,
[00577] - a single-layer or multi-layer graphene structure,
[00578] - a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00579] The carbon structure is of flat elongated conformation (eg having a main development plane) (eg annular as shown in Figures 32 to 34). The carbon structure of the first electrically conductive element of the peripheral heater may have a cross section having a thickness of at least 5 µm: for example the cross section thickness may be between 5 and 300 µm, optionally between 10 and 200. The width cross section may be at least 2 mm, more optionally at least 5 mm. The average electrical resistivity can be greater than 5 Q«mm2/m, which is optionally comprised between 15 and 25 Q«mm2/m.
[00580] The second electrically conductive element shown in Figures 34, 34B comprises a structural substrate 210 that carries a respective carbon structure 211 and at least one protective layer 212 covering the carbon structure on an opposite side to the same of the structural substrate; optionally the carbon structure of the second electrically conductive element is sandwiched between two opposing protective layers 212, wherein the protective layer opposite the structural substrate 210 defines the heating surface 201 of said internal heater; also the carbon structure of the second electrically conductive element includes (or is exclusively formed of) one or more carbon allotropes in the group of:
[00581] - a graphite structure,
[00582] - a single-layer or multi-layer graphene structure,
[00583] - a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00584] Furthermore, the carbon structure may be of flat elongated shape; the carbon structure of the second electrically conductive element of the internal heater may have a cross section having a thickness of at least 5 µm: for example the cross section thickness may be between 5 and 300 µm, optionally between 10 and 200. The width cross-section can be at least 3 mm, more optionally at least 5 mm, further optionally at least 10 mm, and an average electrical resistivity greater than 2 □• mm2/m, more optionally greater than 5 □• mm2 /m.
[00585] The apparatus 1 also includes a supply unit 300 configured to control a power supplied to said peripheral heater and to said internal heater; in the example shown the supply unit is an electrical source unit connected to a control device or a control unit 100 and controlled by it. In accordance with aspects of the invention, the control device 100 is configured to act on the supply unit and is configured to command the supply unit 300 and control a supply of electrical power to the peripheral heater 202 independently of a supply of electrical power to the internal heater 200.
[00586] In further detail, the control device 100 is configured to command the supply unit to perform a heating cycle that includes the following steps:
[00587] increase a peripheral heater heating surface temperature to a first temperature, maintain the peripheral heater heating surface 202 at least at the first temperature for a first distinct time interval, reduce the temperature of the peripheral heater heating surface 202 below said first temperature,
[00588] increase a temperature of the heating surface of the internal heater 200 to a second temperature different from the first temperature, maintain the heating surface of the internal heater 200 at least at the second temperature for a second distinct time interval, reduce the surface temperature heating of the internal heater below said second temperature.
[00589] In the first mode described in this document an energy is transferred to the peripheral heater 202 by applying a voltage to the first electrically conductive element, while an energy is transferred to the internal heater by applying an electrical voltage to the second electrically conductive element .
[00590] Thus, the control device 100 is configured to command the supply unit 300 in order to perform a heating cycle that includes the following steps:
[00591] apply an electrical voltage to the first electrically conductive element to cause the temperature of the heating surface of the peripheral heater to rise to the first temperature,
[00592] maintain said electrical voltage to maintain the heating surface of the peripheral heater at least at the first temperature for a first distinct time interval,
[00593] reduce or nullify the voltage applied to the electrically conductive element to reduce the heater heating surface temperature below said first temperature,
[00594] apply an electrical voltage to the second electrically conductive element to cause the temperature of the heating surface of the internal heater to increase to the second temperature different from the first temperature,
[00595] maintain said electrical voltage applied to the second electrically conductive element to maintain the heating surface of the internal heater at least at the second temperature for a second distinct time interval,
[00596] reduce or nullify the voltage applied to the second electrically conductive to reduce the temperature of the heating surface of the internal heater below said second temperature.
[00597] The control device 100 is configured to command the supply unit to consecutively repeat execution of said heating cycle a plurality of times. In practice, every time a portion of film 18a needs to be attached to the respective tray or to the respective trays (or to the respective support), a heating cycle takes place: during each of said consecutive heating cycles, at least one of said film portions 18a are heat sealed to at least one respective backing or a respective tray.
[00598] In detail, said control device 100 - during each heating cycle - is configured to control the supply unit 300 to supply power to the peripheral heater 202 only for a distinct period of time followed by a period of time when none power is supplied to the peripheral heater 202 to cause and maintain the heating surface of the peripheral heater 202 at least at the first temperature for the first distinct time interval, and to cause a subsequent reduction in the temperature of the heating surface of the peripheral heater 202 below said first temperature.
[00599] In a similar manner, the control device 100 - during each heating cycle - is configured to control the supply unit in order to supply power to the internal heater 200 only for a distinct period of time followed by a period of time when no energy is supplied to the internal heater to cause the internal heater heating surface to rise and maintain at least the second temperature for the second distinct time interval, and to cause a subsequent reduction in the temperature of the internal heater heating surface below of said second temperature.
[00600] The heating cycle can be configured in such a way that the second temperature is lower in relation to the first temperature. For example: said first temperature may be in the range between 150°C and 300°C, while said second temperature is in the range between 180°C and 240°C, more optionally between 200°C and 220°C.
[00601] Furthermore, the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and the second distinct time period has a duration of between 0 .2 and 5 seconds, in particular between 0.5 and 1.5 seconds. Figure 12, which refers to a case where a heat shrinkable film is used, shows that the first temperature is held for 1 second while the second temperature is held for % of a second.
[00602] According to a further aspect, each heating cycle is configured in such a way that the rise in the temperature of the heating surface of the internal heater 200 to a second temperature starts after the rise in the temperature of the peripheral heater 202 to the first temperature (In Figure 12 it is shown that hot shrinkage, eg heating the internal heater to the second temperature, starts 0.25 seconds after heating the peripheral heater to the first temperature). In other words, the start of the second distinct time interval may be slightly delayed in relation to the start of said first time interval in order to avoid (when using a heat shrinkable film) causing a slippage of the peripheral film portion to be sealed to the edge 4c. As shown in Figure 12, the entire duration of said first distinct time slot may be greater than the duration of said second distinct time slot.
[00603] The apparatus 1 may also include a cooling circuit 220 (Figure 2) associated with the upper tool 21 and configured to cool said internal heater 200 and said peripheral heater 202; the cooling circuit being controlled by the control device 100 which is further configured to cause the circulation of a cooling fluid (water or oil or other fluid) in said cooling circuit (in Figure 2 the cooling circuit 220 is schematically shown above heaters 200 and 202) and to regulate a coolant temperature to a temperature significantly below both said first temperature and said second temperature and thus help to obtain a sharp reduction in the heating surfaces of the internal and peripheral heaters after said first and second time intervals.
[00604] As shown in Figure 35, which schematically shows a possible structure of the supply unit 300 and the control device 100 for controlling electrical energy fed to the heater or heaters; the supply unit is an electrical source unit and comprises:
[00605] - at least one impulse transformer 301,
[00606] - at least one set of electrical circuits 302 that connects the pulse transformer to the first electrically conductive element of the peripheral heater 202 and to the second electrically conductive element of the internal heater 200.
[00607] In particular, the set of electrical circuits may include two relays 303 and 304 (for example, SSR-type relays), with each relay being electrically interposed between the impulse transformer and the respective one among said first and second electrically conductive elements and is controlled by the control device 100 in order to apply the appropriate voltages to the first and second electrically conductive elements and thus obtain the heating cycle described above.
[00608] Alternatively, the supply unit 300 may include a dedicated transformer for each conductive element (alternative not shown), that is, at least a first pulse transformer and a first set of electrical circuits connecting the first pulse transformer to the first electrically conductive element, and at least one second pulse transformer and a second set of electrical circuits (not shown) connecting the second pulse transformer to the second electrical impedance.
[00609] In both cases the control device 100 is configured to act on the electrical source unit 300 in order to independently supply an electrical current at a predetermined voltage to the first and, respectively, the second electrically conductive element.
[00610] In a further aspect, again shown in Figure 35, the apparatus, and particularly the packaging assembly 8, may include a first temperature sensor 305 configured to detect a temperature of the heating surface of the peripheral heater 202 and emit a first corresponding temperature signal correlated to the sensed temperature, and an optional second temperature sensor (not shown) to detect an internal heater heating surface temperature and output a second corresponding temperature signal correlated to the sensed temperature. Note that the first and second temperature sensors can be contact temperature sensors or non-contact temperature sensors (eg IR sensors). Also note that the presence of the first/second temperature sensor may not be necessary and the temperature of the heating surfaces can be calculated based on the measured electrical resistance of the first/second electrically conductive element.
[00611] If one or more of said temperature sensors are present, the control device 100 is connected to said first temperature sensor 305, and optionally to said second temperature sensor, and is configured to receive the first temperature signal and controlling the supply unit to supply power to the peripheral heater 202 based on said first temperature signal and a desired value for said first temperature, and optionally to receive said second temperature signal and control the supply in order to supply power to the internal heater based on said second temperature signal and a desired value for said second temperature. This allows for active control of temperatures and thus an efficient delivery of the sealing operation and – where applicable – the shrinkage effect.
[00612] In an alternative the temperature or temperatures of the heating element (or elements) can be deduced from electrical measurements; thus, the presence of the first temperature sensor may not be necessary, and the temperature of the heating surface may be calculated based on the measured electrical resistance of the first electrically conductive element.
[00613] For example, a first electrical sensor can be used, electrically connected or connectable to the carbon structure of the peripheral heater and configured to detect an electrical parameter of said carbon structure and emit a corresponding electrical parameter signal, where the parameter electric comprises one of:
[00614] - an electrical impedance of a prefixed segment of the said carbon structure,
[00615] - an electrical current flowing through said prefixed segment of carbon structure when a prefixed electrical voltage is applied at the ends of said prefixed segment,
[00616] - an electrical voltage detected at the ends of the prefixed segment when a prefixed electrical current is imposed to flow through said prefixed segment.
[00617] The control device may, in that case, be connected to said first electrical sensor, and configured to receive said electrical parameter signal and control the supply unit in order to supply electrical energy to the electrically conductive element of the peripheral heater , optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said electrical parameter signal and on a desired value for a temperature of the heating surface of the heater.
[00618] Note that the control device can also be configured to receive said electrical parameter signal and calculate an actual temperature value of the carbon structure of the peripheral heater based on:
[00619] a value of said electrical parameter and
[00620] a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure.
[00621] Additionally the control device can be configured to control the supply unit in order to supply electrical energy to the electrically conductive element of the peripheral, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of the said voltage, based on said calculated actual temperature value and the desired value for the heater heating surface temperature (for example, based on the difference or rate between said calculated actual temperature value and the desired value for the heater heating surface temperature).
[00622] Similarly, the presence of the second temperature sensor may not be necessary, and the temperature of the heating surface can be calculated based on the measured electrical resistance of the second electrically conductive element.
[00623] For example, a second electrical sensor can be used, electrically connected or connectable to the carbon structure of the internal heater and configured to detect an electrical parameter of said carbon structure and emit a corresponding electrical parameter signal, where the parameter electric comprises one of:
[00624] - an electrical impedance of a prefixed segment of the said carbon structure,
[00625] - an electrical current flowing through said prefixed segment of carbon structure when a prefixed electrical voltage is applied at the ends of said prefixed segment,
[00626] - an electrical voltage detected at the ends of the prefixed segment when a prefixed electrical current is imposed to flow through said prefixed segment.
[00627] The control device may, in that case, be connected to said second electrical sensor, and is configured to receive said electrical parameter signal and control the supply unit in order to supply electrical energy to the electrically conductive element of the heater internal, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said electrical parameter signal and on a desired value for a temperature of the heating surface of the heater.
[00628] Note that the control device can also be configured to receive said electrical parameter signal and calculate an actual temperature value of the carbon structure of the internal heater based on:
[00629] a value of said electrical parameter and
[00630] a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure.
[00631] Additionally, the control device can be configured to control the supply unit in order to supply electrical energy to the electrically conductive element of the internal heater, optionally by regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said calculated actual temperature value, on the desired value for the heater heating surface temperature (for example, based on the difference or rate between said calculated actual temperature value and the desired value for the temperature of the heating surface of the heater).
[00632] In the first embodiment of Figure 2, the upper tool 21 comprises a heating head 310 having a respective active surface 311. In that case the heating head 310 can be mounted for a vertical movement with respect to the upper tool 21, by means of the action of an auxiliary actuator 312 associated with the packaging assembly and controlled by the control device 100. In this mode, the peripheral heater 202 and the internal heater 200 are both carried by said heating head and the heating head is configured to take a film sealing position, preferably in correspondence with said second operating condition of the upper 21 and lower 22 tools: in said film sealing position at least the heating surface of the peripheral heater 202 is configured to press against a top surface corresponding of said portion of film 18a which is pressed against the edge 4c in turn pressed. a against the top surface 23a. This, together with the activation of the heating cycle which is synchronized with the movement of the upper tool and the heating head, allows for the heat sealing of the film portion 18a to the at least one underlying support.
[00633] While the heating head is in said heat seal position, the heating surface of said internal heater is configured to contact or be placed at a preset distance from the top surface of said film portion 18a, such as how to properly heat the central zone of said film portion.
[00634] The control device 100 is configured to control the packaging assembly in such a way that - during each said heating cycle - the heating head maintains said film sealing position and therethrough maintains the peripheral portion 202 of the film portion 18a against top edge 4c, at least during said first distinct time interval, preferably until expiration of said first distinct time interval. Control device 100 may also be further configured to control the packaging assembly in such a way that - during each said heating cycle - the heating head maintains said film sealing position until after expiration of said first and second intervals distinct time periods.
[00635] Note that depending on the needs, the heating surface of the internal heater 200 and the heating surface of the peripheral heater 202 can take different shapes. As already mentioned, the heating surface of the inner heater 200 and the heating surface of the peripheral heater 202 may both have an annular shape and form part of said active surface of the head, with the heating surface of the peripheral heater located at a radial distance. of the heating surface of the internal heater and surrounding it: in this case as shown in Figure 35, in a position radially internal to the heating surface of the internal heater 200, the heating head may have a central recess of fixed volume which - when the upper and lower tools are in said second operating condition - it extends vertically away from the lower tool in order to define a space in which at least a part of a product located on a support positioned on one of said supports is capable of receiving .
[00636] Alternatively, the heating surface of the peripheral heater 202 and the heating surface of the internal heater 200 rest in a common plane with said active surfaces of the heating head with the heating surface of the peripheral heater 202 and which forms part of the they are located at a radial distance from and around the internal heater heating surface 200 (see Figures 2 and 32). Alternatively, the heating head may be in at least two relatively movable bodies: a central body carrying the internal heater 200 and a peripheral body carrying the peripheral heater 202 and surrounding the central body, the peripheral body and the central body are configured to be relatively mobile in order to form the central recess 313. In that case, the volume of the recess is determined by the relative position of the peripheral body with respect to the central body, said central recess being positioned in such a way that - when the upper and lower tools 21, 22 are in said second operating condition - it extends vertically away from the lower tool 22 in order to define a space in which at least a part of a product located on a support is capable of receiving .
[00637] It should also be noted that the heating head may include a means (e.g., a means to generate a vacuum, or mechanical tweezers, or the like) configured to be operative in correspondence to said active surface in order to retain one or more of said film portions in contact with the active surface when the film portion reaches the appropriate position above the respective support or the respective tray 4; alternatively or additionally, the apparatus may include a retaining means (such as tongs or other retaining means) configured to act on opposite longitudinal edges of said film to retain one or more of said film portions 18a in a position aligned with the heating head and said one or more supports.
[00638] Finally, in the first embodiment, the upper tool 21 carries a film cutting unit 320, which is thus hosted within the chamber 24 of the packaging assembly 8, configured to be active in the continuous film 18 and configured to at least cut transversely the continuous film: as shown in Figure 2 the cutting unit 230 can be peripherally positioned outside the peripheral heater 202 and can be pushed towards the film portion 18a (e.g. by the action of pushing elements 322 which include one or more of elastic springs or pneumatic actuators or hydraulic actuators) or positioned relative to the active surface of the heating head 311 such that when the upper tool 21 is lowered and the heating head has moved towards the lower tool 22. A cutting tool 321 of cutting unit 320 touches the top surface of the film portion 18a before the heating surfaces of the waters. inner and peripheral receivers come into contact with the same top surface of the film portion 18a. Note that insert 400 can be sandwiched between the upper and lower tools 21 and 22 to prevent the cutting tool from interfering with the tray edge 4c and to keep the film portion 18a in a proper position during a cut.
[00639] The control unit 100 of the apparatus 1 which is also connected to the conveyor assembly 3, the film drive assembly 5, and the packaging assembly 8 is configured to synchronize the conveyor 46 in such a way that the movement of a preset amount of trays or supports 4 from a region outside the packaging chamber 24 to a region within the packaging chamber 24 as well as the movement of the film 18 is caused to happen when the packaging chamber 24 is opened while the packaging chamber 24 it is closed only once said preset amount of trays or supports 4 and the respective film portions 18a are in a proper position with respect to the upper tool 21.
[00640] Apparatus 1 may also comprise a vacuum arrangement 27 connected to packaging chamber 24 and configured to remove gas from within said packaging chamber; the vacuum arrangement comprises at least one vacuum pump 28 and at least one evacuation tube 29 connecting the interior of said chamber 24 to the vacuum pump; the control unit 100 controls the vacuum pump 28 to remove gas from said packaging chamber 24 at least when the packaging assembly is in said second operating condition, for example with said packaging chamber hermetically closed.
The apparatus 1 may also include or alternatively include a controlled atmosphere arrangement 30 connected to the packaging chamber 24 and configured to inject a stream of gas into said packaging chamber; the controlled atmosphere arrangement comprises at least one injection device that includes an injection pump and/or an injection valve 31 that acts on at least one injection tube 32 that connects the interior of said chamber to a gas source (not shown) which can be located remotely from apparatus 1; the control unit 100 can be configured to control the opening and closing of the injection valve (or activation of the injection pump) 31 to inject said gas stream at least when the packaging assembly 8 is in said second operating condition , for example, with said packaging chamber 24 hermetically closed.
[00642] The control unit 100 can also be configured to control the composition of the modified atmosphere generated within the chamber 24, for example, the control unit 100 can regulate the composition of the gas stream injected into the packaging chamber. The gas mixtures injected into the packing chamber in order to generate a modified atmosphere may vary depending on the nature of the product P. In general modified atmosphere mixtures include a volumetric amount of one or more of N2, O2 and CO2 that is different from quantity of these same gases as present in the atmosphere at 20°C and at sea level (1 atmospheric pressure). If a product P is a product such as meat, poultry, fish, cheese, confectionery or pasta, the following gas mixtures can be used (quantities are expressed in volume percentages at 20°C, 1 atm pressure) :
[00643] - Red meat, skinless poultry: O2=70%, CO2=30%
[00644] - Poultry with skin, Cheese, Pasta, Confectionery: CO2=50%, N2=50%
[00645] - Fish: CO2=70%, N2=30% or CO2=40%, N2=30%, O2%=30
[00646] - Processed meat: CO2=30%, N2=70%
[00647] According to an aspect the control unit 100 may be configured to control said injection pump or said injection valve 31 to start injecting said gas stream or after a preset delay of an activation of said pump of vacuum 28 or after a preset level of vacuum has reached the interior of said packing chamber 24. In a further aspect the control unit 100 can cause the onset of injection of said gas stream to create a modified atmosphere while said 28 vacuum pump is still active so as to shorten the time to create the modified atmosphere. Furthermore, since it is preferable to avoid having too strong a vacuum in the packaging chamber 24 and at the same time it is desirable to ensure a proper atmosphere within the chamber, it is advantageous to stop the vacuum pump after opening the gas injection. In this way a pressure inside the chamber never drops below a desired value. During overlapping the injected gas is mixed with residual air and continues to draw vacuum and the atmosphere with mixed modified air continues to be removed so that the amount of initial air is decreased.
[00648] According to a further aspect, it is observed that the control unit 100 is configured to control said injection pump 31 in such a way that a gas flow is not injected at too high a speed, which can damage the firm retention of the film cut by the top tool. The control unit 100 can control a gas injection at a defined gas pressure below a threshold to prevent the upper tool 21 from coming off or mispositioning in correspondence with it (the injection pressure is kept between 1.3 and 4.0 bar optionally or between 1.5 and 3.0 bar).
[00649] Although apparatus 1 may have one or both of the vacuum arrangement 27 and the controlled atmosphere arrangement 30, it should be understood that the control unit 100 of apparatus 1 may also be configured to firmly engage the film sheets 18 to the trays without activating the vacuum disposition or the controlled atmosphere disposition and thus leaving the normal ambient atmosphere in a tray. This can be, for example, the case for non-perishable products. In a simpler version, apparatus 1 can be designed without a vacuum arrangement and without a modified atmosphere arrangement.
[00650] After the above structural description of the first mode of apparatus 1, the operation of the first mode is revealed below. The operation takes place under the control of control device 100 and achieves a process of packing a product into a tray. In this case, the described process allows packaging under modified atmosphere. In any case, the apparatus 1 is also capable of making a film wrapping of the product. Furthermore, the apparatus 1 can be used to apply a lid to a tray and thus package in a normal ambient atmosphere.
[00651] Once the chamber 24 has been closed, and after the operation of the controlled atmosphere and/or vacuum arrangement (Figures 4 to 6), the control device 100 is configured to act on the auxiliary actuator 312 in order to impose an additional vertical movement to the cutting unit 320 (Figure 7) of the heating head, which reaches the film surface after a cut of the film portion 18a from the remainder of the film 18 (Figure 8). At that point, the peripheral edge 18b of the film portion 18a is confined between the peripheral heating element and the edge 4c of the tray positioned on the support 4. Thus, the control device 100 can start the heating cycle as described above and lead to heating surface of the peripheral heater 202 at the first temperature for a short period of time sufficient to heat seal the peripheral edge 18b to the rim 4c. If a shrinkable film is used, the control device 100 also takes the temperature of the internal heater 200 to the second temperature for a sufficient short time in order to obtain a controlled heat shrinkage of the portion of film covering the nozzle. tray which thus takes on a perfectly controlled flat shape. Figures 9 and 10 schematically show that first the peripheral heater is driven to the first temperature (shaded peripheral heater) and then (Figure (10) the internal heater is also driven to the second temperature (both heaters shaded). the heating cycle is completed, both heaters can be cooled (cut off the power supply to the heaters and optionally circulate a coolant in the cooling circuit 220 (Figure 10)).
[00652] Then the control device 100 opens the packaging chamber 24, and the tray with applied film proceeds downstream of the packaging assembly. The cycle can then be repeated. SECOND MODE OF APPLIANCE 1
[00653] Reference is made to Figures 1A and 13 to 22. The structure of the second embodiment is the same as that of the first embodiment, in that a part of the following differences concerns the packaging assembly 8. Thus, the description given above for the first modality (with the same reference numerals) it also applies for the second modality and is not repeated. Also, the aspects described above (see the first embodiment) in connection with Figures 32, 33, 34, 32A, 32B, 33A, 33B can be used in connection with this second embodiment.
[00654] As mentioned, the only differences between the first and second embodiments concern the packaging assembly which has a heating head 310 mounted on the upper tool 21 in such a way that - when the upper and lower tools are in the second condition of operation - the active surface 311 of the heating head and thus the heating surface of the peripheral heater 202 and the heating surface of the internal heater 200 touch the film before the cutting tool of the cutting device 320 can touch the top surface of film. For example, the cutting device can be attached to the heating head in a position peripherally outside the peripheral heater 202 and leaving the cutting tool 321 retracted relative to the heating surfaces 203 and 201 of the inner and peripheral heaters 200 and 202, which it can be carried by an intermediate body 500 mounted on the heating head 310 for a vertical movement through the action of pushing elements (which can be in the form of one or more elastic springs, one or more pneumatic actuators or hydraulic actuators) configured to push the heaters towards the film portion 18a such that when the upper tool is lowered and the heating head moves towards the lower tool, the cutting tool 321 of the cutting unit touches the top surface of the film portion after the heating surfaces come into contact with the same film portion top surface.
[00655] In this mode the insert 400 may not be present.
[00656] Finally, the second mode may include a vacuum arrangement 27 associated with both the upper tool and the lower tool 20 and 21 and a controlled atmosphere arrangement 30 also associated with both the upper tool and the lower tool 20 and 21.
[00657] The operation of the second mode is as follows. The operation takes place under the control of control device 100 and achieves a process of packing a product into a tray. In this case, the described process allows packaging under modified atmosphere. In any case the apparatus 1 is also capable of making a film wrapping of the product. Furthermore, the apparatus 1 can be used to apply a lid to a tray and thus package in a normal ambient atmosphere.
[00658] Once the chamber 24 has been closed (move from the configuration in Figure 14 to the same as in Figure 15), and after the operation of the controlled atmosphere and/or vacuum arrangements (Figure 16 shows the formation of vacuum and the Figure 17 the creation of controlled atmosphere), the control device 100 is configured to act on the auxiliary actuator 312 in order to impose an additional vertical movement to the heating head 310 and thus bring the heating surfaces of the internal and external heater to a contact with film 18 (Figure 18). At that point, the peripheral region 18b of the film portion 18a is confined between the peripheral heating element heating surface 202 and the edge 4c of the tray positioned on the support 4. Then a further movement of the heating head, for example, operated by the auxiliary actuator 312 drives cutting unit 320 (Figure 19) to drive cutting tool 321 against film 18 and thereby cut film portion 18a. Then, or substantially contemporaneous with the cutting (note, however, that the heating cycle may also start as soon as one of the heaters comes into contact with the film), the control device 100 may begin the heating cycle as described above and bring the heating surface of the peripheral heater 202 to the first temperature for a short time sufficient to heat seal the peripheral edge 18b to the edge 4c. If a shrinkable film is used the control device 100 also brings the temperature of the internal heater to the second temperature for a sufficient short time in order to obtain a controlled heat shrinkage of the film portion covering the tray nozzle which thus takes on a perfectly controlled flat shape. Figures 19 and 20 schematically show that first the peripheral heater is brought to the first temperature (peripheral heater shaded in Figure 19) and then (Figure 20) also the internal heater 200 is brought to the second temperature (both heaters shaded). Once the heating cycle is completed both heaters can be cooled down (cut off the power supply to the heaters and optionally circulate a coolant in cooling circuit 220 (Figure 21). Then control device 100 opens the chamber of packaging 24 in which the tray with applied film proceeds downstream of the packaging assembly. The cycle can then be repeated.THIRD MODE OF APPLIANCE 1
[00659] Reference is made to Figures 1 and 23 to 31. The structure of the third embodiment is similar to the same as the first embodiment minus a part of the following differences. Thus, for the sake of brevity, only the aspects and components of this second modality that differ from those of the first modality will be described: the above description for the first modality in reference to components with the same reference numerals also applies to the third modality and is not repeated. Also, the aspects described above (see the first embodiment) in connection with Figures 32, 33, 34, 32A, 32B, 33A, 33B can be used in connection with this third embodiment.
[00660] Apparatus 1 is adapted for vacuum film packaging of product P, wherein a thin film of plastic material, such as film sheet 18 described below, is stamped deeply into product P and immediately adheres to an edge of top 4c and the inner surface of the support 4 as well as the product surface and thus leaves a minimum amount of air, if any, in the packages. The apparatus 1 can, however, also be used if the film sheet 18 is applied to a tray or a backing with a modified atmosphere previously created in a tray. Apparatus 1 can also be used to pack products on flat supports.
[00661] The frame 2 defines a base body of the apparatus 1 and serves to carry and support various parts of the apparatus 1 as described in this document. The transport assembly 3 for trays 4 is analogous to the same as in the first mode.
[00662] The film drive assembly 5 includes a roll of film 10 that supplies a continuous film 18. The film supply assembly 5 may additionally comprise an arm 11 shown in dashed lines in Figure 1) attached to frame 2 and suitable to support the roll 10. Additionally, the film supply assembly 5 may comprise film punching devices (not shown for the fact that it is known) essentially configured to provide the correct profile for the film edges to abut when cut transversely by cutting unit 320, with tray 4 shaped nozzle with rounded corners. Punching devices can also help to keep an unwound portion of the film pulled from the film roll 10 aligned in accordance with a preset direction. The film drive assembly 5 18 also comprises drive rollers 12 and/or other means for pulling the film from the roll 10 and appropriately positioning it in the cutting station, in correspondence with the film cutting unit 320 (e.g. said means may comprise clips acting on the side of the film and/or clips acting on the front edge of the film and configured to pull the film). The film rolled on film roll 10 can be made and have the structure revealed in the above section dedicated to the film, depending on the specific need.
[00663] The third mode apparatus 1 is designed to cut a continuous film 18 into distinct film portions 18a at a location (a cutting station at which the cutting unit 320 operates) spaced from the packaging assembly 8 and positioned outside the same and for then transporting the cut film portion in the packaging assembly 8, where the film portions 18a are attached to the respective supports or to the respective trays 4. The apparatus 1 comprises a device for transferring the sheet (or sheets) from film cut (or cut) from the cutting station to a position above the tray within the packaging assembly; however, how the cut film sheet is transported to the packaging assembly and above the respective tray or support is not relevant: non-limiting examples of suitable transfer devices are provided in this document below.
[00664] The film cutter unit 320 may be located in the cutter station (see Figure 1 and Figure 23). The cutting unit 320 comprises a cutting tool 321 with a blade and blade piston. This piston can be replaced by any other type of electric, pneumatic or hydraulic linear actuator. The blade piston is preferably attached to frame 2 and is connected to cutting tool 321 so as to push and pull it in a direction transverse to the unrolled portion of film 18, as indicated by the double arrow A2 shown in Figure 1. the film 18 can be unrolled in a vertical direction where the cutting tool moves horizontally.
[00665] The packaging assembly 8 includes a lower tool 22 and an upper tool 21. The lower tool 22 comprises a preset amount of holders 23 to receive said one or more holders 4, while the upper tool 21 is configured to retain at least the cut film sheet (or the cut film sheets). The upper tool and the lower tool are configured to be movable relative to each other between at least a first operating condition, wherein the lower tool and the upper tool are spaced apart and allow the positioning of one or more supports 4 on said supports 23, and a second operating condition, in which the lower tool and the upper tool are brought together so as to define or contribute to defining a packaging chamber 24. In one aspect, the packaging chamber 24 may be hermetically sealed. closed to the atmosphere outside, which means that the packaging chamber 24 can be brought into a condition where it cannot communicate freely with the atmosphere outside the same chamber and a gas can only be supplied or removed from the chamber. through appropriate supply or discharge channels under the control of the apparatus 1.
[00666] As schematically shown in Figures 1 and 23, the cut film portions 18a can be moved in the packaging chamber 24 of the assembly 8 by means of a transfer device. The transfer device can be of any suitable type.
[00667] For example, according to a 1st possible alternative - the transfer device 600 can include a transfer mechanism 601 (Figure 1) which acts on the cut film sheet (or cut film sheets) can be used to transport the film sheet cut from the cutting station where the cutting assembly cuts the film portions 18a into the packaging assembly 8 and then leaving the packaging assembly 8.
[00668] Alternatively, the transfer device may include a displacement mechanism 602 (Figure 23) configured to move the upper tool 21 of the wrapping assembly 8 to the outward position where the cutting unit cuts the film sheets ; in this way the upper tool 21 is allowed to take the cut film portion (or cut film portions) 18a and return to the packaging assembly 8 in alignment with the lower tool 22, and thereby take the cut film portion ( or the cut film portions 18a in the packaging chamber 24 and above the trays. Note that other ways can be considered for transferring a pre-cut film sheet or sheets within the packaging assembly 8, without departing from the scope of the invention: in practice any adapted solution to take the film sheet and transfer it to the packaging assembly may be adequate.
[00669] Finally, as to the packaging assembly 8, the upper tool 21 does not need any cutting unit 320 and the heating head has a respective active surface configured to receive the film portion 18a and particularly of said cut film sheet . The retaining means 330 is associated with the head 310 and is configured to attract the film portion or film sheet 18a towards the active surface 311. The retaining means 330 may comprise a plurality of suction openings 331 leading to the active surface. , at least one vacuum source, for example, comprising a vacuum pump controlled by control device 100 and connected to suction openings 331, and at least one selector valve, also controlled by control device 100, which selectively connects said suction openings or to said vacuum source or to a vent line. The control unit 100 can be configured to activate the holding means by switching the selector valve to a position in which the valve connects the suction openings to the vacuum source and thereby causes the suction of gas through the openings. . Alternatively, two valves can be used which can be selectively opened and closed to determine a fluid connection between said openings either to the vacuum source or to the vent line. Note that in addition to or as an alternative to a vacuum source the retaining means 330 may include one or more of the following:
[00670] - mechanical retainers, such as tweezers, clips or the like,
[00671] -adhesive systems, for example, comprising adhesive portions associated with the active surface 311,
[00672] - heating systems, for example, comprising heatable portions - controlled by control device 100 - associated with retaining means to cause heating of the active surface and thus of the film sheet 18 in order to increase the stickiness of the film sheet on the active surface,
[00673] - electrical systems, for example, the active surface can be charged with a different polarity than typical of the plastic sheet 18.
[00674] Although apparatus 1 may have one or both of the vacuum arrangement 27 and the controlled atmosphere arrangement 30, it should be understood that the control unit 100 of apparatus 1 may also be configured to firmly engage the film portions 18a to the trays without activating the vacuum disposition or the controlled atmosphere disposition and thus leaving the normal ambient atmosphere in a tray. This can be, for example, the case for non-perishable products. Thus, in one version, the apparatus 1 can be designed without a vacuum arrangement and without a modified atmosphere arrangement.
[00675] The operation of the third mode is as follows. The operation takes place under the control of control device 100 and achieves a process of packing a product into a tray. In this case, the described process allows packaging with film under a modified atmosphere. In any case the apparatus 1 is also capable of making a film wrapping of the product. Furthermore, the apparatus 1 can be used to apply a lid to a tray and thus package in a normal ambient atmosphere.
[00676] First, at the cutting station, the cutting unit 320 cuts a portion of film 18a in the form of a sheet of film distinct from the continuous film 18. Then either the upper tool 21 moves to the packaging station and takes the cut film sheet or cut film sheet is moved in the packaging assembly by the transfer device 600. In the latter case the upper tool 21 takes the cut film portion and the transfer device leaves the packaging chamber 24 (Figure 24) . Then, the upper and lower tools are aligned (if necessary) and moved from the first to the second operating condition (see Figures 24 and 25), with the film portion 18a held against the active surface of the heating head by the means of retention 330 of the heating head 310 (and thus also against the heating surfaces of the inner and peripheral heaters): preferably the film 18a is held at a distance from the top surface of the rim 4c.
[00677] Once the chamber 24 has been closed (configuration of Figure 25), and after the operation of the controlled atmosphere and/or vacuum provisions (Figure 26 shows the formation of vacuum and Figure 27 the creation of controlled atmosphere ), the control device 100 is configured to act on the auxiliary actuator 312 in order to impose an additional vertical movement to the heating head 310 and thus drive the heating surfaces of the internal and external heater that carry the cut film portion 18a on the direction of the surface 23a such that the film portion 18a (and in detail a peripheral edge 18b of the film sheet 18a) is pressed against the top surface of the edge 4c (Figure 28). At that point, the peripheral region 18b of the film portion 18a is confined between the peripheral heating element heating surface 202 and the edge 4c of the tray positioned on the support 4. Then, the control device 100 can begin the heating cycle accordingly. described above and bring the heating surface of the peripheral heater to the first temperature for a short time sufficient to heat seal the peripheral region 18b to the rim 4c. If a shrinkable film is used the control device 100 also brings the temperature of the internal heater to the second temperature for a sufficient short time in order to obtain a controlled heat shrinkage of the film portion covering the tray nozzle which thus takes on a perfectly controlled flat shape. Figures 29 and 20 schematically show that first the peripheral heater is brought to the first temperature (peripheral heater shaded in Figure 29) and then (Figure 30) also the internal heater is brought to the second temperature (both heaters shaded). Once the heating cycle is complete, both heaters can be cooled down (cut off the power supply to the heaters and optionally circulate a coolant in cooling circuit 220).
[00678] Then the control device 100 opens the packaging chamber 24 in which the tray with applied film proceeds downstream of the packaging assembly. The cycle can then be repeated. FOURTH MODE
[00679] A fourth embodiment shown with reference to Figures 36 and 37 refers to a packaging apparatus 1 comprising a packaging assembly 8 configured to receive a product P to be packaged and at least one film 18 for packaging the product P, a heater 202 (in the example of Figure 37, two opposing heaters 200, 202 carried by respective heater bars 260 and 262 are shown - obviously a single heater solution is also possible) associated with the packaging assembly and having a surface of heating configured to heat seal one or more parts of said film. In practice the heating surfaces of each heater 200, 202 are flat and straight bands which each act on a respective film 18 or film portion to heat seal the two film portions along a heat seal band, by For example, the two portions of film visible in Figures 36 and 37 may be part of the same tubular film 18 which - once bands in the intersecting direction are formed - creates a film package around the product P.
[00680] The heater 200, 202 comprises at least one electrically conductive element; a supply unit 300 is connected to the electrically conductive element of the heater and configured to supply electrical energy to said heater by causing an electrical current to flow through said electrically conductive element. According to one aspect of the invention, the electrically conductive element comprises an electrically conductive carbon structure 211 of the type described above, that is, it comprises (or is exclusively formed of) one or more carbon allotropes in the group of:
[00681] - a graphite structure,
[00682] - a single-layer or multi-layer graphene structure,
[00683] - a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations: in particular the fullerene structure can take the form of carbon nanotubes or carbon nanofibers.
[00684] In more detail, the electrically conductive element comprises a structural substrate 210 that carries the carbon structure 211 and at least one protective layer 212 that covers the carbon structure on an opposite side to the same of the structural substrate 210. In the embodiment shown , said carbon structure 211 is optionally sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said heater.
[00685] The carbon structure may be of flat elongated conformation having a cross section having a thickness of at least 5 µm and a width of at least 2 mm, which optionally has a cross section having a thickness of at least 10 µm and a width of at least 5 mm.
[00686] The carbon structure preferably has an average electrical resistivity greater than 5 □• mm2/m, which is optionally comprised between 15 and 25 □• mm2/m.
[00687] The control device 100 acts on a supply unit 300 connected to the conductive carbon structures 211. The control device 100 is configured to command the supply unit and control a supply of electrical energy to the heater.
[00688] The control device 100 is in particular configured to command the supply unit 300 to perform a heating cycle which includes the following steps:
[00689] apply an electrical voltage to the electrically conductive element to cause the heating surface of the heater (or heaters) to increase in temperature to a first temperature,
[00690] maintain said electrical voltage to maintain the heating surface of the heater at least at the first temperature for a first distinct time interval,
[00691] reduce or nullify the voltage applied to the electrically conductive element to reduce the temperature of the heating surface of the heater below said first temperature.
[00692] The first distinct time period has a duration comprised between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and the electrical voltage is maintained applied to the electrically conductive element for a period of time substantially equal to the first distinct time period.
[00693] The first temperature may be in the range between 150°C and 300°C, while said second temperature is comprised in the range between 180°C and 240°C, more optionally between 200°C and 220°C. Analogously to the modalities described above, the electrical source unit 300 comprises at least one pulse transformer configured to generate voltage pulses of a duration comprising between 0.2 and 5 seconds (in particular between 0.5 and 1, 5 seconds), at least one set of electrical circuits connecting the impulse transformer to the electrically conductive element: the control device 100 is configured to act on the supply unit 300 to supply electrical current at a predetermined voltage and for a period of predetermined time said electrically conductive element such as to maintain the heating surface of the heater at least at the first temperature for a first distinct time interval sufficient in order to form the heat seal band and then the supply of electrical power is interrupted (or substantially reduced) until the subsequent heating cycle to form the next heat seal strip.
[00694] A first temperature sensor 305 can be provided and configured to detect a heater heating surface temperature and output a corresponding first temperature signal correlated to the detected temperature. Control device 100 is connected to said first temperature sensor, and is configured to receive said first temperature signal and control the supply unit in order to supply electrical energy to the electrically conductive element, optionally by regulating the applied voltage to the electrically conductive element and/or the duration of application of said voltage, based on said first temperature signal and a desired value for said first temperature. Note that the first temperature sensor can be a contact temperature sensor or a non-contact temperature sensor (eg an IR sensor). Also note that the presence of the first temperature sensor may not be necessary and the temperature of the heating surface can be calculated based on the measured electrical resistance of the first electrically conductive element as already discussed for the previous modalities.
[00695] The operation of the fourth mode is as follows. The operation takes place under the control of control device 100 and achieves a process of packaging a product into a film wrapping.
[00696] First, a tubular film is formed in a conventional manner (eg by extrusion or by longitudinally bonding two opposite longitudinal edges of a flat film). Then a product P is positioned inside the cavity formed by the tubular film. Then the assembly formed by the film and product is moved to the packaging assembly 8 along the arrow direction A3 in Figure 37. At regular intervals before and after the product P a transverse sealing band B - which is substantially transverse to the direction of A3 movement - is formed. Each heat transfer seal band B is formed by bringing the heaters 200, 202 against each other or alternatively by bringing a single heater 200 against the film surface, the latter being supported on the opposite side through of a support bar or other support element. Once one or both heaters come into contact with the film and close the two opposite film portions to be sealed against each other, the heating cycle described above can be started. Once the seal is formed the heating cycle is stopped, the tubular film is advanced a preset length and a new seal is formed as described above at a distance from the previous seal and thus closes and seals a pack of film around a product P. APPLIANCE CONTROL DEVICE 1
[00697] The apparatus according to the invention has at least one control unit.
[00698] The control unit 100 may comprise a digital processor (CPU) with memory (or memories), an analog type circuit, or a combination of one or more digital processing units with one or more analog processing circuits. In the present description and in the claims, it is indicated that the control unit 100 is "configured" or "programmed" to carry out certain steps: this can be achieved in practice by any means which allows to configure or program the control unit. For example, in the case of a control unit 100 comprising one or more CPUs, one or more programs are stored in an appropriate memory: the program or programs contain instructions which, when executed by the control unit, cause the unit to control unit 100 perform the steps described and/or claimed in connection with the control unit. Alternatively, if the control unit 100 is of an analog type, then the control unit circuitry is designed to include a circuitry configured, in use, to process electrical signals such as to perform the control unit steps. disclosed in this document.
[00699] In general terms the control unit 100 actuates and controls the transport assembly 3, the film cutting unit 320, the transfer device 46, the packaging assembly 8 and particularly the upper and/or lower tools 21, 22, the vacuum arrangement, the controlled atmosphere arrangement. In particular, the control unit 100 can be configured to control the execution of the processes claimed in the appended claims, the processes described in the summary section and the operations described in the detailed description above.
[00700] Although the invention has been described in connection with what is currently considered to be the most practical and preferred embodiments, it should be understood that the invention is not to be limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent provisions included in the spirit and scope of the appended claims.
[00701] The specific nature of the described actuators is exemplary and alternative types of actuators can be used as long as the type of movement imposed on the moving parts in which said actuators operate is the same.
[00702] Also note that although the modalities described show a single packaging assembly, multiple packaging assemblies can be used in parallel in order to optimize throughput. TECHNICAL EFFECTS AND ADVANTAGES
[00703] The aspects of the invention described above and claimed achieve technical effects and advantages that are briefly summarized in the present document below.
[00704] The possibility of controlling in an independent manner the peripheral heater 202 and the internal heater 200, for example, under the control of the control device 100 and the supply unit 300, allows to have a precise control of the temperature of heating surfaces both in terms of the location where temperatures are increased and in terms of the duration of the temperature rise. This leads to the possibility of using any type of film, ie also films of the heat shrinkable type or films that can be subjected to thermal distortion, and thus ensure the possibility of achieving packaging that has a substantially aesthetic appearance perfect.
[00705] Furthermore, even when using highly shrinkable heat shrinkable films, the process and apparatus according to the invention allow a precise control of the thermal profile in correspondence with the heating surfaces and thus lead to a corresponding precise control of the extent of shrinkage imposed on the processed films so as to minimize uncontrolled deformation in the film and a transmission of forces to the tray that can cause tray distortion.
[00706] In addition, controlling the temperature of the heating surfaces of the peripheral 202 and the internal heater 200 in such a way that the surfaces are brought to the respective first and second temperatures for defined and very short time intervals allows to opportunely delay a transmission of heat to the peripheral region 18b of a film portion 18a relative to heat transmission to the central area of a film portion 18a. Thus, considering having to seal a film portion 18a to the top of a tray 4, it is possible to first start heat sealing from the peripheral region 18b of the film portion 18a to the top edge 4c of the tray 4 and then start heating the zone. central portion of the film (which can shrink or be subjected to thermal stresses) without transferring tangential forces (e.g. forces directed parallel to the top surface of the tray edge) that can compromise the hot bond between the film 18a and the 4c edge, and transfer unwanted stresses to the tray wall. Furthermore, it is possible, according to aspects of the invention, to sharply reduce the temperature of the heating surfaces in particular of the heating surface of the peripheral heater 202 while the same heating surface of the peripheral heater is still in contact with the film and exerts pressure on it which fits against the tray edge, with the consequence that the bonding can take place effectively before the bonding pressure is released and thus obtain a flawless hot bond and still keep the time in extremely short. general to complete the link cycle.
[00707] Furthermore, the precise control of the heating surfaces and the reduced period of time during which said heating surfaces are kept at high temperatures, prevents a heat dispersion and an unwanted heat transmission to other components. In particular the cutting device and the blades associated with the cutting device remain substantially cold and thus avoid problems of sticking, inefficient cutting and the like.
[00708] It should also be noted that the possibility of supplying heat basically on demand, for example, only when the connection execution takes place, leads to significant energy savings.
[00709] When aspects of the invention are implemented using heaters provided with an electrically conductive element in graphene layers, the above effects are further improved as the conductive elements in graphene layers showed a very small thermal inertia ( and so it can be quickly heated and cooled which requires less electrical power and thus less energy from the supply unit), substantially no elongation or no distortion even when taken to temperatures in the range of 200 to 250°C (and thus results in simple structures to run and on reliable heaters). The absence of thermal elongation also leads to perfect planarity of the graphene structures during the entire heating process with the consequent perfect planarity of the heating surfaces and improved efficiency during a hot bonding of the film.

权利要求:
Claims (20)
[0001]
1. Packaging apparatus comprising: a packaging assembly configured to receive a product (P) to be packaged and at least one film for packaging the product (P), a heater associated with the packaging assembly and having a heating surface configured to heat seal one or more parts of said film, the heater comprising at least one electrically conductive element, and a supply unit connected to the electrically conductive element of the heater and configured to supply electrical energy to said heater, causing an electrically current flow through said electrically conductive element, wherein the electrically conductive element comprises an electrically conductive carbon structure, characterized in that it additionally comprises: - at least one electrical sensor electrically connected or connectable to the carbon structure (211 ) and configured to detect an electrical parameter of the carbon structure (211) and outputting a corresponding electrical parameter signal, the electrical parameter comprising one of: an electrical impedance of a prefixed segment of said carbon structure (211), an electrical current flowing through said prefixed segment of the carbon structure (211) when a prefixed electrical voltage is applied at ends of said prefixed segment, an electrical voltage detected at ends of the prefixed segment of the carbon structure (211) when a prefixed electrical current is imposed to flow through said prefixed segment, in which a control device (100) is connected to said electrical sensor, and is configured to:- receive said electrical parameter signal and control the supply unit (300) in order to supply electrical energy to the electrically conductive element, optionally by regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said electrical parameter signal and on a desired value for a heater heating surface temperature (200, 202).
[0002]
2. Apparatus according to claim 1, characterized in that the carbon structure comprises or is exclusively formed of one or more carbon allotropes in the group of: - a graphite structure, - a single layer graphene structure or multiple layers, - a fullerene structure, in which the carbon atoms are bonded together in spherical, tubular, fiber-like or ellipsoidal formations, in particular in which the fullerene structure takes the form of carbon nanotubes or carbon nanofibers. carbon; wherein optionally the electrically conductive element is formed only by the carbon structure.
[0003]
3. Apparatus according to any one of the preceding claims, characterized in that an electrically conductive element comprises a structural substrate carrying the carbon structure and at least one protective layer covering the carbon structure on an opposite side to it of the structural substrate, wherein optionally said carbon structure is sandwiched between two opposing protective layers, wherein, in addition, the protective layer opposite the structural substrate defines the heating surface of said heater.
[0004]
4. Apparatus according to any one of the preceding claims, characterized in that the carbon structure has a flat elongated conformation that has a cross-section with a thickness of at least 5 μm and a width of at least 2 mm, which is optionally a cross section having a thickness of at least 10 µm and a width of at least 5 mm; ewhere the carbon structure has an average electrical resistivity greater than 5 □• mm2/m, which is optionally comprised between 15 and 25 □• mm2/m.
[0005]
5. Apparatus according to any one of the preceding claims, characterized in that it additionally comprises a control device that acts on the supply unit and is configured to command the supply unit and control a supply of electrical energy to the heater, wherein said control device is further configured to command the supply unit to perform a heating cycle which includes the following steps: applying an electrical voltage to the electrically conductive element to cause the heater heating surface to rise in temperature until a first temperature, maintain said electrical voltage to maintain the heater's heating surface at least at the first temperature for a first distinct time interval, reduce or nullify the voltage applied to the electrically conductive element to reduce the temperature of the heater's heating surface below said first temperature; the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and wherein the electrical voltage is maintained applied to the electrically conductive element for a substantially equal period of time to the first distinct time period; and wherein the heater is carried by a heating head of said packaging assembly, the heating heat being movable from a rest position, where it is spaced from the film to be heat sealed, to a sealing position of film, wherein the heating surface of the heater contacts a surface to be sealed of the film, wherein, in addition, the control device is configured to control the packaging assembly in such a way that - during each said cycle of heating - the heating head maintains said film sealing position for at least said first distinct time interval, preferably until the expiration of said first distinct time interval.
[0006]
6. Apparatus according to any one of the preceding claims, characterized in that the electrical source unit comprises: - at least one pulse transformer configured to generate voltage pulses of a duration - intended as a total duration of the sequence of pulses - between 0.1 second and 5 seconds, optionally between 0.2 and 1.5 seconds. - at least one set of electrical circuits connecting the pulse transformer to the electrically conductive element, wherein said control device is configured to act on the supply unit to supply electrical current at a predetermined voltage and for a predetermined period of time to said electrically conductive element.
[0007]
7. Apparatus according to any one of the preceding claims, characterized in that: said packaging assembly is configured to receive at least one support and to firmly attach the film to the support, the packaging assembly including :- a lower tool that defines a preset amount of supports, configured to receive said at least one support with a product (P) to be packaged, - an upper tool facing the lower tool and cooperating with it, in which said upper tool and lower tool are relatively movable at least between a first operating condition, wherein the upper tool and lower tool are spaced apart and allows the positioning of at least a portion of film of said film above a or more among said at least one support, and a second operating condition, in which the upper tool and the lower tool are brought closer together and allow a seal. heating said portion of film to the at least one support located on said preset amount of supports, said heater comprising a peripheral heater carried by the upper tool, and wherein the electrically conductive element comprises a first electrically conductive element which forms part of the peripheral heater, the peripheral heater being configured to heat seal at least a peripheral region of said film portion to the at least one support; and further wherein the control device acting on the supply unit is configured to command the supply unit to perform a heating cycle which includes the following steps: apply an electrical voltage to the first electrically conductive element to cause the peripheral heater heating surface to rise in temperature to a first temperature, maintain said electrical voltage to maintain the heating surface of the peripheral heater, at least on the first. This temperature for a first distinct time interval, reduces or nullifies the voltage applied to the first electrically conductive element to reduce the temperature of the heating surface of the peripheral heater below said first temperature.
[0008]
8. Apparatus according to claim 7, characterized in that the heater further comprises an internal heater also loaded by the top tool and having a heating surface configured to heat at least a portion of said film portion, wherein the peripheral heater surrounds the internal heater, and wherein the electrically conductive element comprises a second electrically conductive element which forms part of the internal heater, and wherein the control device is further configured to control the supply unit in order to supply power electrically to the first electrically conductive element independently of a supply of power to the second electrically conductive element.
[0009]
9. Apparatus according to claim 8, characterized in that, in addition, said heating cycle includes the following additional steps controlled by the control device acting on the supply unit: apply an electrical voltage to the second element electrically conductive to cause the temperature of the heating surface of the internal heater to rise at a second temperature different from the first temperature, maintain said electrical voltage applied to the second electrically conductive element, to maintain the heating surface of the internal heater, at least at the second temperature for a second distinct time interval, reduce or nullify the voltage applied to the electrically conductive second to reduce the temperature of the heating surface of the internal heater below said second temperature.
[0010]
10. Apparatus according to claim 9, characterized in that:- said control device is configured to command the supply unit to consecutively repeat the execution of said heating cycle a plurality of times, during which one of said consecutive heating cycles at least one of said film portions is heat sealed in at least one respective support; - said control device - during each heating cycle - being configured to control the supply unit in order to supply power to the first electrically conductive element of the peripheral heater only for a distinct period of time followed by a period of time when no power is supplied to cause the rise and maintain the heating surface of the peripheral heater at least at the first temperature by distinct first time interval, and to cause a subsequent reduction in the temperature of the heating surface. setting the peripheral heater below said first temperature; and/or - said control device - during each heating cycle - is configured to control the supply unit in order to supply power to the second electrically conductive element of the internal heater only for a distinct period of time followed by a period of time when no energy is supplied to cause the internal heater heating surface to rise and maintain at least the second temperature for the second distinct time interval, and to cause a subsequent reduction in the temperature of the internal heater heating surface below said second temperature.
[0011]
11. Apparatus according to claim 9 or 10, characterized in that the heating cycle is configured in such a way that the second temperature is lower in relation to the first temperature, and wherein said first temperature is comprised between 150°C and 300°C, optionally between 180 to 240°C, more optionally between 200 to 220°C;- said second temperature is comprised between 150°C and 300°C, optionally between 180 to 240°C, plus optionally between 200 to 220°C; wherein additionally the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and wherein the second distinct time period is a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds.
[0012]
12. Apparatus according to any one of the preceding claims 9 to 11, characterized in that additionally the control device is configured to command the supply unit to sharply increase the temperature of the heating surface of the peripheral heater by a respective temperature reference to first temperature with a rate of temperature rise with time greater than 1°C/ms, optionally greater than 5°C/ms; and/or that the control device is configured to command the supply unit to sharply increase the temperature of the heating surface of the internal heater from a respective reference temperature to the second temperature with a rate of increase in temperature with the longest time of the than 1°C/ms, optionally greater than 5°C/ms.
[0013]
13. Apparatus according to any one of the preceding claims 9 to 12, characterized in that each heating cycle is configured in such a way that the increase in the temperature of the heating surface of the internal heater until the second temperature starts after the increase in the temperature of the peripheral heater to the first temperature, with the beginning of said second distinct time interval being delayed in relation to the beginning of said first time interval, optionally the start of the second distinct time interval occurring immediately after the end of first timeslot, more optionally, wherein the duration of said first distinct timeslot is greater than the duration of said second distinct timeslot.
[0014]
14. Apparatus according to any one of the preceding claims 8 to 13, characterized in that: - the heating surface of said peripheral heater has an annular shape and surrounds the heating surface of the internal heater, and - when the tools upper and lower are in said second operating condition, the peripheral heater is configured to heat a peripheral band of said film portion while the internal heater is configured to heat at least a portion of an inner zone of the same film portion located radially within. of the peripheral band, wherein, in addition, the control device is configured to control the packaging assembly in such a way that - during each said heating cycle - the heating head maintains said film sealing position with the peripheral heater in contact with a peripheral band of said portion of film at least during said first distinct time interval, preferably cially until the expiration of said first distinct time interval; wherein in addition: - both the heating surface of the peripheral heater and the heating surface of the internal heater are flat and - at least when the upper and lower tools are in said second condition operation, in which the heating surface of the peripheral heater is: either coplanar to the heating surface of the internal heater or indented with respect to the peripheral surface of the internal heater, such that when the heating surface of the peripheral heater is in contact with the top surface of the film portion, the heating surface of the internal heater is spaced a preset distance from the top surface of the same portion of film. wherein optionally the heating surface of the internal heater is located at a radial distance from the surface of heating the peripheral heater and extends into an area surrounded by the surface of a heating surface of the peripheral heater, said heating surface of the internal heater comprising one selected from the group of: - an annular shaped heating surface, - a continuous heating surface delimited by a single closed contour line, optionally a surface of discoidal or polygonal continuous heating, wherein said continuous heating surface occupies substantially all or a majority of said area surrounded by the heating surface of the peripheral heater, - a heating surface which includes a plurality of spaced parallel strips connected at its ends by cross bands.
[0015]
15. Apparatus according to any one of claims 7 to 14, characterized in that the first electrically conductive element of the peripheral heater extends along the heating surface of the peripheral heater, wherein said first electrically conductive element is a electrically conductive annular element, optionally an electrically conductive annular flat element; wherein additionally said first electrically conductive element has an electrically conductive carbon structure that includes - or is exclusively formed of - one or more carbon allotropes in the group of: a structure graphite, a single-layer or multi-layer graphene structure, a fullerene structure, in which carbon atoms are bonded together in spherical, tubular, fiber-like, or ellipsoidal formations; optionally wherein the fullerene structure takes the form of carbon nanotubes or carbon nanofibers; and/or wherein the second electrically conductive element of the internal heater extends along the heating surface of the internal heater, said second element electrically conductive is one selected from the group of: an electrically conductive annular element, optionally an electrically conductive flat annular element, an electrically conductive continuous plate, an electrically conductive meander element, optionally an electrically conductive plane meander element; second electrically conductive element has an electrically conductive carbon structure that includes - or is exclusively formed of - one or more carbon allotropes in the group of: a graphite structure, a single-layer or multi-layer graphene structure, a fullerene structure , in which the carbon atoms are bonded together in formations and spherical, tubular, fiber-like or ellipsoidal; optionally wherein the fullerene structure takes the form of carbon nanotubes or carbon nanofibers.
[0016]
16. Apparatus according to any one of claims 7 to 15, characterized in that: - the first electrically conductive element comprises a structural substrate that carries a respective carbon structure and at least one protective layer covering the carbon structure on a side opposite the same of the structural substrate, optionally wherein said carbon structure is sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said peripheral heater; - optionally wherein the Carbon structure of the first electrically conductive element of the peripheral heater has a cross section having a thickness of at least 5 µm and a width of at least 2 mm, more optionally a cross section having a thickness of at least 10 µm and a width of at least 5 mm, and an average electrical resistivity greater than 5 □• mm2/m, which is optionally comprised between 15 and 25 □• mm2/ m; and/or that:- the second electrically conductive element comprises a structural substrate bearing a respective carbon structure and at least one protective layer covering the carbon structure on an opposite side to the same of the structural substrate, optionally wherein said structure of carbon is sandwiched between two opposing protective layers, the protective layer opposite the structural substrate defining the heating surface of said internal heater; - optionally wherein the carbon structure of the second electrically conductive element of the internal heater has a cross-section with thickness of at least 5 µm and a width of at least 5 mm, plus optionally a cross section with a thickness of at least 10 µm and a width of at least 10 mm, and an average electrical resistivity greater than 2Q^ mm2/m, optionally greater than 5Q^mm2/m.
[0017]
17. Apparatus according to any one of the preceding claims, characterized in that the control device is configured to:- receive said electrical parameter signal and calculate an actual temperature value of the carbon structure based on: a value of said electrical parameter, and a calibration curve or a calibration table stored in the control device and referring values of the electrical parameter with corresponding values of the temperature of the carbon structure; - control the supply unit in order to supply electrical energy to the electrically conductive element, optionally regulating the voltage applied to the electrically conductive element and/or the duration of application of said voltage, based on said calculated value of the actual temperature and on the desired value for the temperature of the heating surface of the heater.
[0018]
18. Use characterized by the fact that it is an apparatus, as defined in any one of the preceding claims, for packaging a product (P): - by heat sealing a heat shrinkable film to support on which said product (P) has previously been placed or - by positioning at least one shrinkable film around the product (P) and then heat-sealing one or more portions of said heat shrinkable film to one another.
[0019]
19. Process of packaging a product (P) arranged on a support using an apparatus, as defined in any one of the preceding claims 8 to 17, in which the process is characterized by the fact that it comprises the following steps:- positioning a or more supports in correspondence with said one or more supports, - positioning at least a portion of film or at least one sheet of film above a respective one or more supports located on said one or more supports, - holding the tools upper and lower in said first operating condition a sufficient time for the supports and for the film portion or the corresponding film sheet to properly position, - move the upper and lower tools in said second operating condition with said film portion or sheet of film positioned above the respective support or supports, optionally at a sufficient distance to allow a gas circulation within the support, - optionally where in said second condition operating the upper and lower tools define a hermetically sealed packaging chamber with the process including causing one or both of: a removal of gas from the hermetically sealed packaging chamber and an injection of gas into the packaging chamber of a gas mixture of controlled composition, - heat sealing the film portion or the film sheet to the backing, the heat sealing step including the following substeps: making the heating surface of the peripheral heater come into contact with the surface of film sheet top or film portion of the support or supports located on said support or on said supports, increasing a temperature of the heating surface of the peripheral heater to a first temperature, maintaining the heating surface of the peripheral heater at least at the first temperature for a first distinct time interval, reduce the temperature of the heating surface of the peripheral heater to below said first temperature, causing the heating surface of the internal heater to contact or be placed at a preset distance from the top surface of said portion of film, increasing a temperature of the heating surface of the internal heater to a second temperature different from the first temperature, so as to maintain the heating surface of the internal heater at least at the second temperature for a second distinct time interval, so as to reduce the temperature of the heating surface of the internal heater below said second temperature,- position the upper and lower tools in said first operating condition, - move the amount of supports with the film firmly attached away from the packaging assembly.
[0020]
20. Process according to claim 19, characterized in that the heat sealing includes heating with the peripheral heater a peripheral band of said portion of film or film sheet and heating with the internal heater an internal zone of the same portion of film or sheet of film located radially within the peripheral band, where the film is not heat shrinkable and the first temperature is equal to the second temperature or where the film is heat shrinkable and the second temperature is lower to the first temperature; wherein the first distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, and wherein the second distinct time period has a duration of between 0.2 and 5 seconds, in particular between 0.5 and 1.5 seconds, in which additionally the temperature of the heating surface of the peripheral heater is increased from a respective reference temperature to first temperature occurs with a rate of temperature rise with time greater than 1°C/ms, optionally greater than 5°C/ms; wherein optionally increasing the temperature of the heating surface of the internal heater of a respective temperature of reference to the second temperature with a rate of temperature rise with time greater than 1°C/ms, optionally greater than 5°C/ms.

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同族专利:

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公开号 | 公开日

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AU2015329972B2|2020-05-14|

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BR112017007124A2|2017-12-19|

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NZ730878A|2020-12-18|

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MX2017004598A|2017-06-30|

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EP3204211B1|2020-07-08|

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CN107000878B|2020-04-24|

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AU2015329972A1|2017-04-27|

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RU2017111660A|2018-11-12|

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US20170305586A1|2017-10-26|

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WO2016055599A1|2016-04-14|

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CN107000878A|2017-08-01|

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EP3736114A1|2020-11-11|

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ES2817349T3|2021-04-07|

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RU2675532C2|2018-12-19|

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EP3204211A1|2017-08-16|

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RU2017111660A3|2018-11-12|

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法律状态:
2020-02-18| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2021-07-06| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-08-24| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 08/10/2015, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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EP14188562.4|2014-10-10|

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EP14188562|2014-10-10|

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PCT/EP2015/073320|WO2016055599A1|2014-10-10|2015-10-08|Apparatus and process for packaging a product|

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