APPLIANCE AND METHOD FOR VAPORIZING A VAPORIZABLE DIELECTRIC SUBSTANCE FROM A MATERIAL, SYSTEM FOR V

专利摘要:
apparatus and method for dehydration using microwave radiation. an apparatus for extracting a vaporizable substance from a material containing such a substance comprises an irradiation chamber to irradiate the material with electromagnetic radiation to vaporize the substance. the substance can comprise water and the material is dehydrated. electromagnetic radiation comprises microwaves. irradiation is conducted in the neighboring field of electromagnetic radiation. in one aspect, the electromagnetic radiation in the waveguide evanescently couples with the material.
公开号:BR112015011291B1
申请号:R112015011291-9
申请日:2013-11-18
公开日:2020-12-15
发明作者:Greg Stromotich；Terumi Stromotich；Paul Burgener
申请人:Nuwave Research Inc.；
IPC主号:

专利说明:

Reference to previous orders
[001] The present application claims priority under the Paris Convention for US application number 61 / 727,563, filed on November 16, 2012, the entire content of which is incorporated here for reference. FIELD OF THE INVENTION
[002] The present disclosure relates to apparatus and methods for microwave dehydration, and in particular to microwave dehydration of temperature sensitive biological and organic materials. BACKGROUND OF THE INVENTION
[003] The dehydration of various materials by exposure to microwave radiation at reduced atmospheric pressures is well studied. See, for example, M. Zhang et al., “Trends in microwave related drying of fruits and vegetables”, Trends in Food Sciences & Tecnology, 17 (2006), 524-534 (the full content of which is incorporated here for reference ). In general, a reduction in atmospheric pressure reduces both the boiling point of water and the oxygen content of the atmosphere. Vacuum microwave dehydration processes, VMD, can therefore allow dehydration to occur in the absence or reduction of oxygen, and without exposing the material being dehydrated to significantly elevated temperatures, thereby providing dry products that can have better physical, organoleptic and / or chemical qualities compared to dry products obtained using other dehydration processes known as hot air convection or freeze drying. VMW processes can also be relatively fast and energy efficient compared to many other dehydration processes. Temperature and / or oxygen sensitive materials of the type that are known to be favorable to drying by VMD include, but are not limited to, food products such as fruits, vegetables, berries, herbs, meat, fish, seafood, dairy products , prepared foods, seeds, grains, roots and tubers, as well as a wide variety of agricultural food products, pharmaceutical and nutraceutical products, dietary supplements, synthetic organic compounds and the like.
[004] As is well known, VMD can be performed as a batch or continuous process, and a typical VMD device will comprise at least one vacuum chamber (in which an input material is dehydrated in a final product), a headset microwave radiation and associated detection equipment (eg, infrared detectors), and control equipment (eg, programmable logic controller, “PLC”), to monitor the status of the product during the dehydration procedure and perform necessary or desirable adjustments. For example, such monitoring may include monitoring the material's surface temperature (such as by using infrared detection) or surface texture (for example, wrinkling). In continuous VMD processes, the apparatus will also typically comprise input and output means such as vacuum chambers that allow the input material and final product to enter and exit the vacuum chamber, respectively, without interrupting the vacuum level, and a means of transport (for example, a conventional conveyor belt) to transport material through the vacuum chamber between the inlet and outlet ends.
[005] It has been generally established in relation to known VMD processes that a higher microwave field strength will have a greater effect (as measured over the complete drying cycle) in increasing the rate of dehydration than does a more vacuum deep. A primary focus of the state-of-the-art VMW apparatus and process engineering has therefore been to maximize the intensity of microwave radiation that can be applied to the material being dried.
[006] To maintain the overall objectives of maximizing microwave field strength while controlling the temperature gain of the material being dried, the microwave emitters (eg, magnetrons) of current CMD devices are typically located outside the chamber irradiation, or vacuum, where they can be operated in atmospheric conditions (and protected from conditions in the chamber). The microwave radiation generated by the emitters enters the vacuum chamber through one or more transparent microwave windows, typically after being transported through one or more waveguides. Various microwave waveguides are known in the art. Non-gas dielectric waveguides include types of micro strip, coaxial, and strip line. However, such dielectric waveguides convert some of their energy to heat (that is, they are "lost"), and typically cause microwave fields to be established on the outer surfaces of the waveguide. For most microwave applications, this results in microwave radiation interacting with something that is close to the dielectric waveguide. For these reasons, the waveguides used to transport microwaves from the emitter to the irradiation chamber are generally also kept outside the chamber. Such placement serves to reduce the occurrence of high voltage standing waves caused by microwave reflection, which can lead to sparking in the waveguide. Thus, in typical known microwave dehydration devices and methods, the material to be dehydrated is generally subjected to microwave radiation in the neighboring field region.
[007] In general, as known in the art, the power density in the neighboring electromagnetic field region is reduced as the square of the distance from the source. However, in the neighboring field region (ie, a distance that is comprised of approximately one wavelength of electromagnetic radiation, but possibly extending as far as to include a transition zone that ends at approximately two wavelengths), fields very high electromagnetic waves that do not decrease as the square of the distance can occur. This allows relatively high field strengths to be developed in the neighboring field region.
[008] There is a need for an improved device and / or method to dehydrate materials such as food products and the like, using microwave radiation that overcomes at least one of the deficiencies known in the art. SUMMARY OF THE INVENTION
[009] In one aspect, the invention provides an improved apparatus and method for extracting a vaporizable substance from a material using application of electromagnetic radiation in the neighboring field range. In one example, the substance is water and the apparatus and method comprise the application of microwave radiation to the material. The material can be any organic or inorganic material, including fruits and vegetables or extracts thereof. In a preferred embodiment, irradiation is conducted under vacuum conditions.
[010] In one aspect, the invention provides an apparatus for vaporizing a vaporizable substance from a material, the vaporizable substance being subjected to vaporization after exposure to electromagnetic radiation, the apparatus comprising: - an irradiation chamber; - an electromagnetic wave generator; and - a waveguide adapted to direct the electromagnetic waves generated towards the material and to irradiate the material in a field region neighboring the electromagnetic waves.
[011] In another aspect, the invention provides a method for vaporizing a vaporizable substance from a material, the vaporizable substance being subjected to vaporization after exposure to electromagnetic radiation, the method comprising: - providing a raw material containing the vaporizable substance; - to introduce the raw material in an irradiation chamber; - irradiate the raw material with electromagnetic radiation in the neighboring field, the electromagnetic radiation being sufficient to heat and vaporize the substance, thus resulting in a treated material in which a portion of the substance was extracted from the raw material, and - remove the treated material from the irradiation chamber.
[012] In another aspect, the invention provides a system comprising a plurality of apparatus described herein, in which the material is treated sequentially with the same or different irradiation conditions. BRIEF DESCRIPTION OF THE DRAWINGS
[013] For a more complete understanding of the nature and advantages of the material disclosed, as well as the preferred way of using it, reference should be made to the following detailed description, read in combination with the attached drawings. In the following drawings, similar reference numerals designate the same or similar parts or steps.
[014] Figure 1 is a side perspective view of a microwave dehydration device according to a modality of the revealed matter.
[015] Figure 2a is a side perspective view of the embodiment of Figure 1 without an input power unit or an output power unit.
[016] Figure 2b is an extreme perspective view of the embodiment of figure 2a.
[017] Figure 3 is a perspective view of the assembly of the transport tray of the modality of figure 1.
[018] Figure 4 is a perspective view of the plurality of microwave sources of the modality of figure 1.
[019] Figure 5 is an enlarged perspective view of a single microwave source as shown in Figure 1.
[020] Figure 6 is an enlarged perspective view of a single non-gas dielectric waveguide assembly according to an alternating modality of the revealed matter.
[021] Figure 7 is an enlarged perspective view of a single non-gas dielectric waveguide assembly according to an additional alternative embodiment of the disclosed matter.
[022] Figure 8 is an enlarged perspective view of a single gas dielectric waveguide assembly in accordance with an additional alternative embodiment of the disclosed matter.
[023] Figure 9 is an enlarged perspective view of a non-gas dielectric waveguide assembly according to an additional alternative embodiment of the disclosed matter. DETAILED DESCRIPTION OF A SPECIFIC MODE
[024] Throughout the following description and drawings, in which similar and corresponding parts are identified by the same reference numerals, specific details are exposed to provide a more complete understanding of the material currently revealed to persons skilled in the art. However, well-known elements may not be shown or described in detail to avoid unnecessarily obscuring the disclosure. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.
[025] In this description, reference will be made to the terms "irradiation chamber" and "vacuum chamber". The term "irradiation chamber" will be understood to comprise a chamber in which electromagnetic radiation, preferably microwave, is applied to a material to effect dehydration or removal of a vaporizable component from the material. In cases where such irradiation is conducted under vacuum, the term "vacuum chamber" can be used to refer to the irradiation chamber. In some embodiments, the irradiation chamber can be pressurized to a pressure greater than atmospheric pressure. In other embodiments, no pressure or vacuum is applied to the irradiation chamber. As further discussed below, due to the way in which electromagnetic energy is transmitted to the material being treated, very little, if any leakage of electromagnetic radiation escapes from the material. As such, the irradiation chamber would not require any shielding or the like, in which case the term "irradiation chamber" will be understood to mean an "irradiation zone" or "irradiation region" since a discreet enclosure would not be necessary. Thus, as used here, the term “chamber” does not necessarily indicate a complete enclosure.
[026] The following description is mainly aimed at removing water, or dehydration, from a given feed material. Such dehydration is preferably carried out using electromagnetic radiation; preferably microwave radiation. As will be recognized by persons skilled in the art, the apparatus and method described here can be used to remove any vaporizable substance.
[027] Furthermore, although the present description is mainly directed at the removal of a vaporizable substance, the apparatus and method of the invention can also be used to simply heat a material and / or sterilize it. For example, in one aspect, a water-containing material, such as wood and the like, can be processed with the apparatus or method of the invention to heat, but not vaporize, the water contained therein. In such a case, the material being treated can be subjected to a pressure greater than atmospheric pressure, so that water vaporization is inhibited or avoided. The material temperature can then be raised to the desired sterilization temperature, which can be maintained for a desired period of time.
[028] In one aspect, as described in the present disclosure, the invention provides an apparatus and method that uses a waveguide, such as a non-gas dielectric waveguide, to provide microwave radiation for the purposes of dehydrating materials ( in particular organic materials, such as temperature sensitive organic and biological materials, including fruits and vegetables). In one aspect, the invention comprises supplying microwave materials to the materials to be dehydrated in the neighboring field. This is facilitated by the use of one or more waveguides, which allow microwave radiation to be confined to the waveguide and space around to the point of use, where the material being dehydrated is placed on or within the region surrounding countryside. Without being limited to any specific theory, it is believed that exposure to microwave radiation in such proximity results in an evanescent coupling of the electromagnetic radiation emitted by the waveguide (acting as a source) and the material (acting as a receiver).
[029] By placing the material being dehydrated in the neighboring field of a dielectric waveguide, a high power field can be brought up to the surface of the dielectric waveguide and used to wrap the material in high field levels without experiencing reflection or significant transmission of microwave radiation in an irradiation chamber, as would occur when a microwave beam in free space (ie, far-field radiation) reaches the dehydration material that has reached a low moisture content state and it becomes a bad absorber of microwave radiation. As is known in the art, as the moisture content of a material decreases, it becomes generally less lost, making it increasingly difficult to dissipate sufficient power throughout the material and it becomes necessary to surround the material with a high intensity field. By radiating the material in the neighboring field region, the electromagnetic field can be concentrated on or near the surface of the waveguide and into the material to be dehydrated. Conversely, in a gas-filled waveguide that is transmitting through free space, the electric field needs to increase to pass more current through the impedance of the material to be dehydrated, and the increase in voltage can lead to sparking.
[030] In current state-of-the-art CMD devices and processes, water vapor and vacuum conditions in the vacuum chamber can create microwave ionization concerns. Sparkling can occur when microwaves transition into the vacuum chamber, and / or from reflections and edge effects in the chamber, causing high voltage fields to be established and ionizing water vapor in the chamber (and resulting in rupture or discharge arcs that can damage the device and / or the material being dehydrated). Conversely, the non-gas dielectric waveguide according to one aspect of the present disclosure couples the microwave radiation to the material in the neighboring field, such that the material acts similar to a loss defect on the waveguide surface, thereby avoiding the generation of high voltage distant field conditions. Limiting at least part of the microwave radiation to non-free space operation in the waveguide thereby reduces ionization and breakage.
[031] With waveguides having a high dielectric constant, microwaves are mostly contained in the dielectric material. When it is desired to have the microwaves directed to a surface adjacent to the material being dehydrated, a transition to a lower dielectric constant material can be used or the dielectric material can be made thinner. This provides design flexibility without creating high-power microwave fields propagating through the free space of the vacuum chamber. To further increase design choices, highly conductive or metallic patterns can be applied on or in the dielectric material, thereby allowing microwaves to shift in the dielectric and conductors.
[032] As outlined above, the waveguides of the invention allow microwaves to move along them until they are dissipated into a lost material. This feature provides a mechanism to deliver microwave energy directly to the material being dehydrated, that is, in the neighboring field region, and not just reflect randomly from the surfaces in an irradiation chamber, as it would occur when a beam of radiation-free space Microwave is used to irradiate a specific area in the chamber. In one embodiment, the material to be dehydrated is spaced on the waveguide (or, for example, on a conveyor belt that has been configured as a dielectric waveguide). In such an embodiment, the microwave radiation continues along the waveguide until it reaches the material. In another embodiment, the material may be supplied on a conveyor belt and the waveguide may include gaps, or voids may be present between a series of individual waveguide elements in a single device, which are sized to allow coupling field adjacent to adjacent waveguide elements continue.
[033] In some embodiments, a non-gas dielectric waveguide may comprise a liquid, solid or semi-solid or a suspension. The use of a "flow" dielectric material as a guide from where it provides not only a waveguide for microwave containment, but also a mechanism for changing the properties of the dielectric in a stopped or continuous flow condition. This allows cooling or heating to be provided to the dielectric material and through conduction and radiation, also to the material being dehydrated. In addition to changing the temperature, the dielectric properties of the waveguide can be altered by changing the properties of the fluid and, by flowing it through appropriate valves, allows the dielectric properties to match more closely with the conditions required to provide the necessary conditions to attach energy to the dehydration material as its electromagnetic absorption properties change. Dielectric properties of the waveguide can be altered by changing the chemical composition, adding or removing suspended particles such as carbon and metal particles, colloids, molten materials, gels and pastes and the like. In some embodiments, the changing dielectric properties of the material being heated and dehydrated can themselves be used in the calculation and / or control of the dielectric waveguide materials and properties. In addition, by changing the dielectric properties of the non-gas dielectric waveguide, the microwave wavelength can be changed to better match the material being dehydrated and match the material load with the output of the microwave generator without requiring adjustment operating frequency. This allows low cost, high power magnetron microwave sources to be used instead of higher cost, variable frequency microwave sources.
[034] A non-gas dielectric waveguide according to an aspect of the present invention can be shaped to act not only as a waveguide, but also as a microwave lens. Refractive lenses can be formed in ways known to those skilled in the art to concentrate microwave radiation in a certain location or plane. These lenses can be solid surfaces like concave and convex optical lenses or they can provide focusing through Fresnel shaped lenses. A conductive material pattern can also be applied to or inserted into the dielectric material to form lenses. These techniques limit microwaves to dielectric materials that prevent or reduce the development of high free space and sparking voltages in a vacuum environment.
[035] Still in additional embodiments, a non-gas dielectric waveguide can comprise multiple layers of dielectric materials to affect the waveguide and dielectric properties. Alternating layers of conductive materials and dielectric materials can also be used. Typically, the reduced atmosphere or vacuum in a VMD device provides a high potential difference between the free space and the dielectric waveguide, which tends to assist in containing microwave radiation in the dielectric waveguide material. However, if the waveguide needs to pass close to where power would be passed to another component, then a layer of material can be added to the waveguide to provide a different refractive index or different reflective property.
[036] Similarly, non-gas dielectric waveguides having different loss properties at different locations can be used. Such waveguides allow microwave radiation to act as a mechanism to heat the waveguide material and provide conductive and radiative heating of the dehydration material as it rests on or near the dielectric waveguide. Susceptors can be used in free space microwave heating, however this requires more complex fabrication and is sensitive to the mechanical stability of the susceptor close to the material. The absorption of microwaves by susceptors also depends on the microwave path in a chamber and the shape of the susceptor in the microwave plane. When agitators and even different types of dehydration material and charge are present in a chamber, the internal microwave distribution changes. With a dielectric waveguide that incorporates a lost dielectric material, microwave radiation is provided and matched to the waveguide as the waveguide will limit the microwave radiation to a defined path. The average power may decrease due to the loss to the dehydration material, but the wave characteristics remain the same as the wave moves along the dielectric waveguide. This feature also allows incorporation of proper termination of the waveguide so that no reflections or standing waves are generated in the waveguide, which is important in preventing high voltage nodes from developing in free space that can lead to sparking in a vacuum environment.
[037] A non-gas dielectric waveguide can also comprise different surface characteristics. Sharp edge patterns such as narrow tips, triangles, ridges, etc., can be added to the waveguide surface and thereby alter the local field strengths. Sharp edges or points can increase field strength over a very short distance and can be beneficial when trying to create a strong field in small dehydration materials like a single berry on a conveyor. The use of the dielectric waveguide in the neighboring field allows standardization of the surface which helps to provide the microwave power to the material while not affecting the creation of high voltage discharge points. The standardization of the neighboring field would be of no propagation to free space.
[038] In additional aspects of the matter currently revealed, electromagnetic radiation (For example, microwave) is evanescently coupled to the material being heated or dehydrated and the magnitude of unbound electromagnetic radiation in the device is felt using antennas such as tubes, guides waveform with slits, adhesive and strip line to collect the unabsorbed microwaves that have passed through the material to be dehydrated. The antennas feed a microwave circuit that detects phase or intensity and sends a voltage to the controller using principles as taught, for example, in US patents. 3,789,296 and 3,965,416. Commercial devices such as the Hydronix Hydro-Probe ™ can be used as an independent microwave moisture sensor and used to quantify the current dielectric value of the material being coupled. In combination with the results of a thermal sensor, the current moisture level of the material can thus be determined. This information, in turn, can be used to control the power, phase, dielectric property and / or frequency of the microwave emitter, and / or the vacuum level in the vacuum chamber, in a way that maximizes the effectiveness of vaporization and minimizes the risk of thermal leakage, carbonization or application of excess radiation and damaging the material being dehydrated. A plurality of such sensors and emitters can be employed along a path that the material being dehydrated travels through the apparatus, and the application of energy and temperature can thus be controlled throughout the dehydration process. Such configurations allow the dielectric measurements and thermal measurements of the product as it is transported through the device, to be sent to a programmable logic controller, or PLC, and result in the dielectric profile of the material being dehydrated to be used in the control of the process. dehydration.
[039] It is well known that the moisture content will change the dielectric constant and that the measurement of the dielectric content of a product being dehydrated can be used to determine the progress of dehydration. However, to control the microwave power to maintain an internal temperature of the material being dehydrated, it is necessary to predetermine the dielectric constants of the product to be processed in advance of entering the MVD device. This requires product measurements at varying levels of dehydration to create a set of calibration data that is sent to the control PLC or computers so that they maintain the vacuum pressure and applied microwave power and / or frequency in the desired levels for each stage of the dehydration process. Optimal processing requires specific product data since dielectric measurements are also affected by other physical and chemical factors, such as salt content, particle size, and packing density. The approach described in relation to some modalities of matter presently revealed here differs from previous attempts to use dielectric constant to measure moisture in which the dielectric constant of the effective material to be processed is pre-measured in the same way that it will be entering the VMD device, such that the VMD measurement of the dielectric constant will be calibrated to the effective state of dehydration.
[040] In modalities where internal microwave emitters are incorporated along the surface used to transport the material being dehydrated, control and detection capabilities are especially important. The ability to determine, for example, with built-in circuitry, the dielectric characteristics of the material as it passes over an emitter allows the emitted microwaves to be adjusted in an operation optimized for that specific piece of material at that specific time and place . A set of emitters with a set of control and detection circuits can then adapt to any piece of material as it passes through each emission element in the set. In a preferred embodiment, the set of detection circuits can be incorporated in the emitters and use signals derived from a partial reflection of the microwaves being used to heat the material to be dehydrated. The use of low-power solid-state emitters on panels of hundreds of emitters then provides full coverage of the material being dehydrated and can even provide the same total power as single modules of higher power generators. The use of small dielectric waveguides and lenses will then protect the emitters and circuitry operating in the vacuum vessel, while providing microwaves for all conveyor surfaces.
[041] In yet other modalities, if it is desired to dehydrate materials without taking advantage of the lower boiling point that is provided by reduced atmospheric conditions, non-oxygen gases can be used to provide an atmosphere that is not oxidizing, thereby allowing dehydration of oxygen sensitive materials at atmospheric pressures and above. The use of a non-gas dielectric waveguide (and any substrates, such as lenses, etc.) is still advantageous when used in non-vacuum conditions where the existing atmosphere can otherwise ionize and lead to sparking.
[042] The figures attached to the present illustrate a modality of a microwave dewatering apparatus of the invention, comprising a single vacuum chamber with a continuous supply of material to be dehydrated. In the illustrated embodiment, the apparatus includes waveguides, as described here, to guide microwave radiation towards materials to be dehydrated. Although the figures illustrate a preferred embodiment of the invention comprising an apparatus and method using a conveyor means (such as a conveyor belt) to treat material in a continuous process, it will be recognized that the invention can also be practiced in a batch format. Furthermore, although the illustrated embodiment illustrates an irradiation chamber, it will be understood that multiple chambers can also be provided in other embodiments. Such multiple chambers need not be all vacuum chambers. Several other modalities would be evident to people with common knowledge in the art in view of the teaching of the present revelation.
[043] A dehydration apparatus according to one embodiment of the invention is generically illustrated at 10 in figure 1. Apparatus 10 comprises a processing unit 12 in which a material to be dehydrated can be dehydrated by exposure to microwave radiation to produce a dehydrated product. The dewatering apparatus 10 includes an inlet supply unit 14 and an outlet supply unit 16 to allow raw materials to enter the processing unit 12 through the inlet valve 18, and the dehydrated materials to exit from the unit. process 12 through outlet valve 20. The inlet supply unit 14 and outlet supply unit 16 can be of any design or construction known as would be known in the material handling technique. In a preferred embodiment, the processing unit 12 comprises an irradiation chamber that is maintained in a vacuum condition. In such an embodiment, the input feed unit 14 and output feed unit 16 would be understood to be adapted to maintain a desired atmospheric condition (e.g., vacuum) in the processing unit 12 of the apparatus 10. The flange supports 22 are supplied at either end of the processing unit 12 for sealed connection to the input supply unit 14 and output supply unit 16, and for mounting on a support frame (not shown).
[044] Inlet supply unit 14 and outlet supply unit 16 are illustrated in figure 1 as a series of valves separated by vacuum chambers, but the selection and implementation of other types of conventional inlet and outlet supply units that are capable of maintaining a pressure differential in the processing unit 12 while allowing the entry and exit of materials and product would be included in the common knowledge of those with knowledge of the technique. In the illustrated embodiment, a single processing unit 12 is fixed between the input supply unit 14 and the output supply unit 16; however, it will be understood that, in other embodiments, a plurality of processing units 12 can be coupled together in an end-to-end arrangement, directly through flange supports 22 or through one or more intermediate input feed units 14 and / or outgoing feed units 16. In such an embodiment, the material being treated would therefore be subjected to a series of dehydration treatments where this is considered necessary. As will be understood, the need for additional processing units 12 would depend, for example, on the nature of the material being dehydrated. That is, some materials may require more dehydration than others. It will also be understood that, in other embodiments, the length of the processing unit 12 can be varied to subject the material to any desired microwave exposure time.
[045] In the illustrated embodiment, the processing unit 12 comprises a vacuum chamber 24, at least one microwave source 26, and at least one orifice 28 configured for connection to a conventional vacuum generator (not shown) and for removal of moisture from the vacuum chamber 24. In the embodiment of figure 1, ten microwave sources 26 and three holes 28 are illustrated. However, it will be understood that any number of microwave sources 26 or holes 28 can be provided and that such numbers would depend, for example, on the length of the processing unit 12.
[046] In embodiments of the invention where a vacuum is applied, such a vacuum can be generated by any means known as with a conventional condenser and pump, as shown in 37 in figure 2b. As is known in the art, having the water condensed in the vacuum chamber, by placing the condenser in the irradiation / vacuum chamber, increases the effectiveness of the vacuum. However, this also presents two problems, namely, (i) condensed water can absorb the microwaves in the chamber and thereby decrease the effective microwave field in the chamber and (ii) sparking locations can be created at the edges of the condenser. According to the modalities of the invention, the condenser can be located outside the vacuum chamber or inside. If located outside the chamber, and thus having any water condensing outside the chamber, the above problems would be alleviated. However, even if capacitor 37 is located inside the chamber, for the reasons discussed above, the problems mentioned above would be reduced since the invention involves the application of microwaves in the neighboring field range. That is, the applied microwaves would be absorbed mainly by the material being dehydrated and, therefore, a minimum amount of radiation would be available for absorption by the condensed water. However, to further decrease against such microwave absorption, an appropriate radiation shield (ie microwave) screen, not shown, can be provided at a location above the condenser and puddle of condensed water (no shown), and below the waveguides 42. Thus, even in the event of leakage of a little microwave radiation after application to the material, such escaped waves would be prevented from reaching the condenser or the puddle of condensed water.
[047] In other embodiments of the invention, a radiation shield (i.e., microwave) screen 32 can be provided at a distance above the carrier 46. Such screen 32 serves to contain the reflection of any escaped radiation. However, it will be understood that a screen as shown in 32, while having certain advantages (ie, containment of microwaves), can also result in certain harmful effects if not controlled. For example, the concentration of microwaves in the region just above the conveyor can result in hot spots being formed, which in turn can result in burning the material being dehydrated.
[048] The placement of the condenser 37 in the vacuum chamber 24 but outside the microwave containment container 30 (to isolate the condenser from microwave radiation) increases condensation and a reduction in the vacuum load of the apparatus 10. In several VMD devices known in the art, the condensers are contained in the vacuum chamber, but there is no provision to isolate the condensed water from being exposed to a microwave again. As a result, known VMD devices allow water to be recycled from the condenser to the steam and then condensing again. this process of vaporization and reconditioning decreases the efficiency of the VMD device. Conversely, according to one embodiment of the present invention, by employing a microwave containment container 30 to isolate the condenser from microwave radiation while still allowing the condenser to be in close proximity to the vaporization event, efficiency is increased. In other embodiments, moisture vapor can be removed by incorporating ionomers (such as Nafion ™ membranes manufactured by PermaPure ™) in the vacuum chamber 24 to ionically combine with moisture and allow the transfer of steam directly to piping leading to the condenser without affecting the vacuum pressure.
[049] As best seen in figures 4 and 5, in one embodiment of the invention, each microwave source 26 comprises a microwave emitter 38 coupled, through at least one conventional dielectric transition 40, to at least one guide non-gas dielectric wave 42 and a substrate, preferably a dielectric substrate 44. The substrate 44 would preferably comprise a lens or microwave applicator. The dimensions of lens 44 can be calculated based on the values of U (permissiveness of the medium in relation to air) and Er (dielectric constant of the medium in relation to air) of the dielectric material from which the waveguide 42 and lens 44 are constructed. . For example, based on the U and Er values of waveguide 42 and lens 44 and using known formulas, as taught in US 8,299,406, a person skilled in the art would be able to build a waveguide 42 that supports any mode of desired electromagnetic transmission (i.e., microwave), as well as a substrate (lens) 44 that disperses microwave radiation. US 6,037,906 also discloses the manufacture of antennas and dielectric lenses.
[050] The apparatus shown in the figures also includes a conveyor 46, in which the material being dehydrated is transported through processing unit 12. The conveyor 46 can be similarly constructed of a dielectric material and is dimensioned (in relation to its U values and Er) in such a way that electromagnetic radiation cannot propagate through carrier 46 in regions where carrier 46 is not in close proximity to a lens 44. In this way, each microwave source 26 provides a defined zone to provide energy from microwave for the material being dehydrated. In a preferred embodiment, microwave radiation is delivered to the material in the neighboring field region. As would be understood by people skilled in the art, in such a region, evanescent coupling of microwave energy to the material being dehydrated occurs.
[051] In one embodiment, the carrier 46 itself can comprise the lens mentioned above. That is, the conveyor belt 46 may comprise a dielectric material that allows it to act as the substrate or lens 44 mentioned above. In such a case, it will be understood that a separate lens 44 would not be necessary for the apparatus. Suitable materials for belt 46, particularly to act as a lens, would include high density polyethylene (HDPE).
[052] At least one RF sensor 48 and thermal sensor 50 are provided in the device of the invention. In a preferred embodiment, at least one RF sensor 48 and at least one thermal sensor 50 are provided in close proximity to each neighboring field coupling zone. Readings from sensors 48 and 50 are fed back to a PLC (not shown) programmed to properly control the output of microwave generators 26 and / or conventional vacuum generator. Thermal and RF sensors can be any sensor as known in the art.
[053] In the illustrated embodiment, the dielectric waveguide 42 comprises a slit antenna 52 (see figure 5). Slit arrangement 54 is selected to provide uniform transmission of radiation from waveguide 42 to the substrate, or lens or applicator 44. Slit size, location and distribution 54 can therefore be determined according to U and ER values of the dielectric material being used, and the frequency of electromagnetic radiation being transmitted.
[054] The relationship between the intensity of microwave radiation generated by any given microwave generator 26 and microwave radiation detected by a corresponding RF sensor 48 is used, in combination with the current thermal properties of the material being dehydrated (as detected, for example, by a corresponding thermal sensor 50) to calculate the current moisture level of the product being dehydrated, as well as the relative risk of thermal leakage.
[055] Electrically small loops, those whose total conductor length is small (typically 1 / 10th of the wavelength in free space) compared to the wavelength in free space, are the most frequent receiver antennas used as probes with field strength measurements. When an electrically small loop is used as a receiving antenna, the voltage developed at its open circuit terminals V is proportional to the component of the incident magnetic flux density B perpendicular to the plane of the loop: V = ®jNAB, in which the incident field is assumed to be uniform over the loop area. This simple relationship between V and B makes the small loop useful as a probe for measuring the magnetic flux density, where N = number of turns and A = loop area.
[056] The small loops are constructed from coaxial cable with the inner conductor looped back and attached to the outer shield which allows cheap probes to be manufactured cheaply and to be easily located in areas of interest. The voltage from the probe is rectified by a diode and measured with a voltage meter or used as a PLC voltage input.
[057] In operation on a VMD device according to the illustrated mode, a sensor, after being installed in the desired location, needs to be calibrated by measuring the voltage output without product to be dehydrated present in variable microwave power settings . Next, material to be dehydrated is placed under the sensor, typically by stopping the conveyor belt, and voltages are measured at the same power settings used in determining the sensor response without material to be dehydrated. This provides a data set that corresponds to the power supplied and dielectric effects of the material to be dehydrated. The combination of this calibration with the data set previously developed from the measurements of the material to be dehydrated and its dielectric constant at different humidity levels, a control algorithm can then supply power to the material to be dehydrated without exceeding the dielectric heating requirement. internal temperature to a desired level of moisture in the material at a specific stage of the dehydration process. To provide adequate voltage for control purposes, a small excess power level is required to allow the probe to detect a microwave level above the material being dehydrated. However, operating in the neighboring field of the substrate or dielectric waveguide, the microwave field would be generally evanescent and would not propagate into free space and lead to high voltage concerns from waves reflected in the vacuum chamber.
[058] An algorithm in the PLC uses inputs from the various sensors provided in the device and controls the microwave generator 26 in order to generate an appropriate amount of microwave radiation, calculated to ensure its conversion into energy latent vaporization, and to ensure that the material being dehydrated dehydrates under desired conditions. Sensors that transmit information to the PLC would typically include field sensors, including sensors for measuring field strength and / or wave frequency, and quality or temperature sensors adapted to measure material parameters. For example, some examples of the sensors mentioned last include fiber optic devices, such as the Ocean Optics OptoTemp 2000 ™ probe, which is unaffected by microwaves for contact and point measurements, or an infrared (IR) sensor as a sensor. Omega Infrared ™ temperature model OS35-3- MA-100C-24V, which would provide a non-contact temperature measurement and material moisture measurement using a dielectric microwave measurement probe such as Hydronix hydro-Probe II ™. Since some microwave energy can be absorbed by the substrate (or lens) 44, the waveguide 42 and / or conveyor 46, the total energy generated by the microwave generator 26 is not transmitted directly to the material being dehydrated.
[059] As the material being dehydrated loses moisture, its dielectric value generally decreases, and the material becomes less effective in transferring microwave energy directly to the vaporization energy. The matter currently disclosed, therefore, also provides the use of accumulated thermal energy in the material being dried, waveguide 42, substrate 44, and the conveyor 46 to heat the water contained in the material being dried in a controlled and measured manner. This approach allows a person skilled in the art to control the intensity of energy supplied to the material being dehydrated through substrate 44 and / or conveyor 46, as well as the speed at which conveyor 46 moves, in one or more processing units 12 in such a way. so that a greater or lesser number of the generated microwaves is applied directly for vaporization or indirectly (through thermal transfer) for vaporization.
[060] This approach also allows control of the vapor pressure in the microwave processing unit (s) 12 in such a way as to allow vaporization to occur at low temperatures as the material dielectric value decreases and dehydration advances, and has the added benefits of increased energy efficiency while still providing a reduction in the risk of thermal overload of the material being dehydrated. As a result, sparking (which can result in carbonization events in the material being dehydrated) is avoided or reduced, and final products with superior physical, organoleptic and / or chemical qualities can be produced.
[061] The rate of progress through each processing unit 12 can be regulated by the algorithm operating on the PLC to ensure that adequate reduction in moisture is achieved before the material is removed from the final output feed unit 16. In addition, the rate of progress from the isolated processing units 12 can be used to control the rate of vaporization at different moisture levels of the products being dehydrated. As each processing unit 12 can be manufactured with different substrates 44, conveyors 46 and waveguides 42, the PLC can also monitor the dehydration progress to better match the current optimal dehydration process of the material.
[062] Figures 6 to 9 illustrate alternative waveguide assemblies according to revealed matter modalities. Variations and additional features
[063] It is known that vacuum microwave drying (VMD) experiences several problems with sparking and non-uniform heating of material being dehydrated. Sparkle results from high voltage nodes developing from constructive and destructive microwave interference that creates large voltage differences that lead to ionization and electrical sparking. Another reason for sparking is due to resonant structures that again develop high voltage and ionization. Low pressure atmospheres reduce the voltage required for ionization to occur, which increases the risk of ionization and sparking. The optimal design for microwave transmission would eliminate wave interference and remove resonant structures. It would operate at high pressures.
[064] Another problem with microwave dehydration is non-uniform heating of the material being dehydrated. This results from different thicknesses and surface areas of the material, which leads to different diffusion rates of water from within the material reaching the surface and changing to steam. Energy needs to be supplied to provide the vaporization heat required for the humidity to allow it to change state. This energy can be supplied through convection, conduction or radiation. Microwaves are a form of radioactive heating. However, to provide heat to the water, microwaves need to be absorbed and dissipated as heat in the material. The physics of microwave dissipation is well known, with such dissipation mainly comprising dielectric heating (vibration of atomic and molecular structures) and conductive heating (resistive heating). Obtaining microwave heating depends on the microwaves interacting with the material to be dried. As will be understood, the physical and chemical properties of the material will affect the way in which microwaves are dissipated. For example, the material may be too small to significantly interact with the applied microwaves or the material may only partially absorb the microwaves, that is, the material may reflect or refract the microwaves. In addition, the material may have properties that result in microwave conduction, which can create magnetic fields that protect the material against additional microwave absorption, or the material can be highly microwave-absorbing, leading to large current flows and overheating. Additional combinations of size, composition, microwave frequency, and microwave field all lead to difficulties in providing a consistent amount of controlled energy being dissipated in the material being dehydrated.
[065] In this disclosure, the applicants reveal that the problems experienced with the present VMD processes can be overcome by changing the way in which the microwaves are contained and directed in the vacuum environment. Currently, microwaves are contained in hollow metal waveguides and chambers and are directed towards the material to be dehydrated by highly conductive materials or metal of various geometric shapes of tubes and cracks and openings that allow microwaves to move through free space or a transparent microwave window into the material to be dehydrated. This allows microwaves to develop interference patterns and resonant conditions leading to the previously described difficulties in sparking and inconsistent temperature control in the material being dehydrated. Applicants have established that if the microwaves are contained in a waveguide, such as a non-gas dielectric waveguide, through the use of dielectric material containing the microwaves, the effect is to eliminate the resonances and interferences that occur in the inside the vacuum chamber. Just as high pressure atmospheres reduce ionization problems, a non-gas dielectric medium reduces ionization problems. The dielectric waveguides contain microwaves that allow structures to be used that minimize or contain interference since the non-gas dielectric is a stable configuration that does not vary the microwave pattern other than in amplitude, with the quantities changing physical and chemical properties of the material to be dehydrated. The containment of microwave fields by the dielectric waveguide removes reflections and resonances experienced when microwaves are allowed to reflect surfaces in the vacuum chamber. The use of non-gas dielectric material can be combined with gas-filled waveguides or conductive shielding to allow microwave containment to interact with other components when the dielectric material is close to other objects. A characteristic of dielectric waveguides is that microwaves in the neighboring field are present on the surface and extend into the free space surrounding the dielectric waveguide. This has been a major problem in the past with the use of microwave dielectric waveguides because they interact with material that is comprised in the neighboring field (typically less than two wavelengths apart). The use of shielding material or a metal waveguide when the dielectric is required to be located close to other structures eliminates this problem. However, the combined neighboring field surface and free space wave allows the microwaves to be brought to the material being dehydrated without allowing them to propagate in the free space of the chamber. The material being heated or dehydrated when it is included in the neighboring field of the guide will interact with the microwaves and dissipate the wave as heat. This means that the dielectric waveguide provided the microwaves for the material without problems with resonance or reflection or high voltage. Dielectric waveguides can be manufactured that allow all normal well-understood waveguide practices to be used. Power splitters, couplers, curves, tees and antennas can be used.
[066] Strip line, coaxial, plane guides, metal in dielectric all make use of dielectric properties to contain and use structures and microwaves in microwave waveguides not filled with gas. As taught here, these same known methodologies can now be applied to VMD as the dielectric properties allow for transitions from dielectric material usage and configuration to another without generating ionization in the vacuum atmosphere and are capable of providing microwave energy to the material being dehydrated as long as the material is included in the neighboring field of the non-gas dielectric material. Different dielectric materials can be used to change the wavelength of the microwaves at a specific frequency in such a way that components of different size of the material being dehydrated are able to couple with the microwave frequency because their dimensions will allow the waves interact better instead of being reflected or only partially enter, which would happen with a big change in wavelength. The ability to change the interaction of particles of different size by changing dielectric properties reduces the complexity and cost of changing frequencies to allow coupling with varying particle sizes of the material being dehydrated.
[067] The use of waveguides, such as dielectric waveguides, allows microwaves to be directed towards the mechanical structures and components in the dehydration chamber, also referred to here as the irradiation chamber or, where a vacuum is used, a vacuum chamber. Preferably, waveguides are made of materials that are compatible with food or meet other regulated requirements. Such materials include Teflon ™, polypropylene, polyethylene, HDPE, or other constructed liquids or plastics. These materials can also be used for the walls forming the irradiation chamber or the conveyor belt. In addition, waveguides are manufactured with dimensions that are defined to allow microwave propagation in the material as it acts as a dielectric waveguide. In this way, microwaves can be directed through the system and into the mechanical structure and components that are in contact with the material to be dehydrated without any microwaves being propagated to the free field space away from the chamber. Using the aforementioned waveguide materials and dimensions, it is possible to use surfaces in the chamber that would otherwise lead to cutting (stopping the movement of microwaves in free space to proceed or propagate inside) since the field regions neighboring the microwaves will still allow heating of the material being dehydrated to occur.
[068] In other modalities, the device can be equipped with several concentration points to locally increase the microwave field strength. Concentration points can be formed by providing small points or bumps on the surfaces of the irradiation chamber, including the walls of the irradiation chamber, the conveyor belt or the lenses. Such concentration points improve the heating effect in materials being dehydrated which have low absorption characteristics. The concentration points would not allow a microwave field to be propagated into free space, but they will concentrate the neighboring surface and field region in areas of higher power. This type of interaction is referred to as evanescent wave interactions. Evanescent wave interaction can be generated in gas-filled waveguides, however the use of a non-gas dielectric material allows significantly better coupling and modification of the wavelength that can be obtained with variable openings in gas-filled waveguides.
[069] In an additional embodiment of the material presently disclosed, a vacuum microwave drying device is provided in which the microwave micro emitters are outside the vacuum chamber and the gas-filled dielectric waveguide has material solid dielectric that protrudes into the vacuum chamber and thereby reduces reflection at the interfaces.
[070] In an additional embodiment of the presently disclosed matter, the apparatus of the invention includes at least a means of measuring the microwave field at a predetermined point or points. Such a means of measuring the microwave field may comprise one or more detectors, which can be used to measure the microwave field strength and allow manual or automatic modification of the behavior of the microwave generators to control energy microwave oven supplied to the irradiation chamber. For example, the power generated can be limited to a percentage of microwaves in excess of what can be absorbed by the material being dehydrated and dielectric material inside the chamber.
[071] In an additional embodiment of the material presently disclosed, the apparatus of the invention includes a means of generation and / or microwave detection. Such a means may comprise one or more detectors provided across the width and / or length of the irradiation chamber to better control or effect energy transfer uniformity.
[072] In an additional modality of the matter currently disclosed, one or more of the dielectric waveguides can be provided with a cooling medium to dissipate any heat generated. For example, the waveguide can be cooled by a refrigerant circulating around its exterior or inside. In this way, the waveguide can be maintained at a given temperature in order to avoid temperature-dependent changes in the mechanical or electrical properties of the waveguide.
[073] In an additional modality of the material presently revealed, the waveguide is arranged so as to result in the coupling of the microwaves to the substrate or lens in which the material to be dehydrated is in proximity or in contact. In this way, the microwaves move through the substrate and couple with the material being dehydrated. The geometry and chemical properties of the substrate, preferably a dielectric substrate, tend to spread and uniform the microwave field as well as act as a charge to absorb excess microwaves and inhibit resonance and reflections. The heat generated in the dielectric waveguide and / or substrate can be transferred to the material to be dehydrated.
[074] In an additional embodiment of the material presently disclosed, the substrate 44 can be omitted and, instead, the conveyor belt 46 can be adapted to perform the function described above. That is, the conveyor belt can comprise a dielectric material and is thus allowed to operate in the same way as the dielectric substrate described above. In one example, as discussed above, the conveyor belt can be made of a material such as HDPE, which has dielectric properties. In another aspect, the belt itself can act as the waveguide. For example, the belt may be of sufficient thickness to allow electromagnetic radiation from the generators to travel along it until it is absorbed by the material. It will be understood that according to the invention, the material would be subjected to radiation from the neighboring field, preferably resulting in evanescent coupling of the radiation with the material. Alternatively, the carrier can simply allow microwaves to penetrate through it, which would result in irradiation of the material being dehydrated. In other embodiments, a tank, basket or plate can be used instead of a conveyor belt. Generally, any device can be used to move the material to be dehydrated from the feed system to the discharge system, whose geometry and chemical properties increase the microwave coupling with the material being dehydrated or the microwave distribution through the material being dehydrated.
[075] In an additional modality of the matter currently disclosed, the measurement of the magnitude of electromagnetic radiation not coupled to the device can be detected and used to quantify the current dielectric value of the material being coupled. Such a measurement can be used to interpret the material's current dielectric value as it is dehydrated. In this way, the microwave frequency or intensity can be modified to limit the percentage of microwaves in excess of what can be absorbed in the material to be generated.
[076] In an additional embodiment of the material currently disclosed, the dielectric value of the material being dehydrated can be used to modify the vacuum pressure, in cases where a VMD process is used. As will be understood, modifying the vacuum pressure would allow changes in the vaporization temperature. In this way, the temperature to which the material is subjected during dehydration can be adjusted in order to reduce the damaging effects of heat on heat sensitive compounds in the material being dried are thereby reduced. For example, in the case of materials that are highly sensitive to damage from heat, the pressure in the irradiation chamber can be reduced, thereby reducing the requirement for higher heat in the chamber. Heat-sensitive compounds in the materials being dehydrated may include, but are not limited to, antioxidants, pigments, vitamins and proteins, and enzymes, as well as other molecules from which nutraceutical and / or organoleptic properties are derived.
[077] In an additional embodiment of the material currently disclosed, the lenses and / or waveguides can be shaped based on the desired refraction and / or transmission properties, in order to adjust the microwave distribution as desired.
[078] In an additional modality of the matter currently disclosed, the microwave generators can feed independently into the vacuum chamber and can be controlled in phase in order to interface with the generated microwaves.
[079] In an additional embodiment of the material presently disclosed, a number of processing units 10 can be connected in series. In this way, each of the processing units can be adjusted with different operating parameters, such as pressure, frequency or microwave field strength, travel speed through, etc. for example, the material to be dehydrated can be subjected to different vacuum pressures to control the vaporization temperature at different stages as the material's dielectric values change in the course of the dehydration process. In such an example, the material can be subjected to a lower pressure (i.e., deeper vacuum) when the dielectric value decreases, and / or the percentage of microwaves in excess of what can be absorbed in the material can be varied. The reduction in vaporization temperature results in a reduction of the thermal damage done to the material being dehydrated during the course of the dehydration process.
[080] In an additional embodiment of the material presently disclosed, the material being dehydrated may comprise fruits, vegetables, fruit juices, vegetable juices, pre-cooked grains, bacterial cultures, vaccines, enzymes, protein isolates, hydrocolloids, injectable drugs , pharmaceutical drugs, antibiotics, antibodies, meat, fish, seafood, milk, cheese, whey protein isolates, yoghurts, fruit extracts, vegetable extracts, meat extracts, or any combination thereof.
[081] In an additional modality of the material currently disclosed, non-oxygen gases can be used to provide an atmosphere that is not oxidizing, in which case the material to be dehydrated includes oxygen-sensitive materials.
[082] The present description has so far described the dehydration of materials by removing water. However, it will be understood that, in other embodiments, the present invention can be adapted to remove other vaporizable constituents, such as organic or inorganic solvents, or to cause a chemical change such as polymerizing a resin.
[083] In an additional embodiment of the material presently disclosed, different loss properties and different surface characteristics at different locations can be used. Sharp edge patterns such as narrow tips, triangles, ridges, ridges can be added to the surface of the waveguide or substrate and thereby change the local field strengths.
[084] In an additional embodiment of the material currently disclosed, sensors and emitters in the container can be used along a path alongside or along the surface used to transport the material to be dehydrated, such that a set of emitters with set of detection control circuits it would then adapt to any piece of material to be dehydrated as it passes through each element of the set.
[085] In an additional embodiment of the material currently disclosed, the dielectric waveguide or substrate is a flow dielectric that allows the dielectric properties to be altered to maximize the intensity of microwave radiation that can be safely applied to the material being dry.
[086] In an additional embodiment of the material currently disclosed, a method of dehydrating a material is provided, comprising the steps of:
[087] A. introducing a quantity of a material to be dehydrated in a feeding mechanism of a first processing unit;
[088] B. reduce pressure in the feeding mechanism to less than atmospheric pressure to match that of an adjacent vacuum chamber;
[089] C. transfer the material to be dehydrated from the feeding mechanism into the vacuum chamber where it is placed in close contact or proximity with a substrate that is excited by a plurality of microwave sources, such that microwaves in excess is limited and the microwave flow can be triggered off in phase and / or power level or frequency can be modulated so that the microwave flows intertwine in the substrate, and the material to be dehydrated absorbs the highest percentage microwave, and in such a way that the heat absorbed in the substrate is allowed to transfer to the material to be dehydrated, and that the detection of excess microwave results in a PLC effecting the microwave source to change the amount or frequency microwaves or the dielectric properties of the waveguide or substrate;
[090] D. taking away the steam resulting from the supply of sufficient energy to vaporize moisture from the material to be dehydrated and out of the microwave containment container by a difference in vacuum pressure;
[091] E. regulate the pressure of the vacuum vessel by the PLC so that the vacuum pump, condenser, and microwave sources ensure that the vaporization temperature is at a level optimized for the current dielectric value of the material to be dehydrated;
[092] F. As the material to be dehydrated transports from the feeding mechanism to the discharge mechanism, respond through the PLC to dielectric values of the material to be dehydrated;
[093] G. transferring the material to be dehydrated into the discharge mechanism of the first processing unit, where the material is isolated from the pressure of the previous container; and
[094] H. subject the material to be dehydrated to the vacuum pressure existing in the next processing unit, and repeat steps cag as the dehydration material advances through each subsequent dehydrator processing unit and a second batch of a defined amount of material it enters the machine as described in step a, in which the pressure reduction from the processing unit to the processing unit corresponds to the optimum parameter to decrease the vaporization temperature of the material dielectric drying profile.
[095] In an additional embodiment of the material currently disclosed, a method of dehydrating a material in a VMD is provided which comprises a single processing unit, the method comprising the steps of:
[096] A. introducing the material to be dehydrated in a feeding mechanism;
[097] B. reducing pressure in the feed mechanism to less than atmospheric pressure to match that of an adjacent vacuum vessel;
[098] C. transferring the material to be dehydrated from the feed system to the vacuum container where it is placed in contact or close proximity to the substrate which is excited by a plurality of microwave sources such that excess microwaves are limited and microwave flow can be activated and deactivated in phase and / or energy level or frequency in such a way that the microwave flows intertwine in the substrate, and the material to be dehydrated absorbs the highest percentage of microwaves, and such that the heat absorbed in the substrate is allowed to be transferred to the material to be dehydrated, and that the detection of excess microwave results in a PLC effecting the microwave source to change the frequency amount of the microwaves;
[099] D. taking away the steam resulting from providing enough energy to vaporize moisture in the material to be dehydrated and out of the microwave containment container by a difference in vacuum pressure;
[0100] E. regulate vacuum vessel pressure by the PLC in such a way that the vacuum pump, condenser and microwave sources ensure that the vaporization temperature is at an optimum level for the current dielectric value of the material to be dehydrated;
[0101] F. respond through PLC control as the material to be dehydrated dehydrates changes in dielectric values of the material to be dehydrated by modifying the operating pressure of the vacuum vessel and / or the amount or frequency of microwaves generated to reduce the temperature of the material to be dehydrated as its dielectric value decreases to such an extent that the dielectric value corresponds to that of the target moisture level of the material; and
[0102] G. remove the dehydrated material using a discharge mechanism.
[0103] In an additional embodiment of the material presently disclosed, a method is provided as described above, in which the pressure reduction from the processing unit to the processing unit corresponds approximately to that of the optimum parameter to decrease the vaporization temperature of the material to be dehydrated, as the dielectric decreases during the course of dehydrating the material to be dehydrated to the desired moisture level.
[0104] In an additional embodiment of the material presently disclosed, a method is provided as described above, in which the material to be dehydrated comprises or is chosen from fruits, vegetables, fruit juices, vegetable juices, precooked grains , bacterial cultures, vaccines, enzymes, protein isolates, hydrocolloids, injecting drugs, pharmaceutical drugs, antibiotics, antibodies, meats, fish, seafood, milk, cheese, whey protein isolates, yogurts, fruit extracts, vegetable extracts, meat extracts or any combination thereof.
[0105] In an additional embodiment of the material presently disclosed, a method is provided as described above, in which the material to be dehydrated is fresh and / or frozen.
[0106] In an additional embodiment of the material presently disclosed, a method is provided as described above, where the material to be dehydrated is encapsulated in a hydrocolloid.
[0107] In an additional embodiment of the material presently disclosed, a method is provided as described above, where the pressure reductions range from 0.01 to 100 Torr, more preferably from 0.1 to 30 Torr, or less than or equal to 760 Torr. As described above, the provision of a vacuum in the irradiation chamber is preferred in order to reduce the vaporization temperature of water or other substance being removed from the material. The main advantage offered by such reduced pressures is the reduction in any damage to heat-sensitive materials or components in the materials. However, as will be understood, in some modalities, a vacuum may not be necessary in the irradiation chamber.
[0108] In an additional embodiment of the matter presently disclosed, a method is provided as described above, in which the pressure reductions are less than or equal to 760 Torr.
[0109] In an additional embodiment of the material presently disclosed, a method is provided as described above, in which the method is conducted under non-vacuum conditions, which is under a pressure greater than or equal to 760 Torr (or 1 atmosphere).
[0110] Although the invention has been described with reference to certain specific modalities, several modifications thereof will be evident to those skilled in the art. Any examples provided here are included solely for the purpose of illustrating the invention and are in no way intended to limit the invention. The drawings provided here are solely for the purpose of illustrating various aspects of the invention and are not intended to be scaled or in any way limit the invention. The scope of the claims annexed to the present should not be limited by the preferred modalities set out in the description above, but it should receive the broadest interpretation consistent with the present specification as a whole. The disclosures of all prior art mentioned here are incorporated herein by reference in their entirety.

权利要求:
Claims (37)
[0001]
1. Apparatus for vaporizing a vaporizable dielectric substance from a material, the vaporizable dielectric substance being subjected to vaporization after exposure to microwave energy, the apparatus comprising: - a processing chamber; - one or more microwave generators, to generate microwaves having microwave energy; and - one or more waveguides adapted to confine the microwave energy to such one or more waveguides and surrounding area, and to direct, in the neighboring field, the microwave energy to the material; CHARACTERIZED by the fact that the one or more waveguides are non-gas dielectric waveguides adapted to direct the generated microwave energy to the material by coupling the microwave energy to the material in an evanescent way.
[0002]
2. Apparatus according to claim 1, CHARACTERIZED by the fact that one or more non-gas dielectric waveguides are comprised of a solid, semi-solid or liquid material.
[0003]
3. Apparatus, according to claim 1 or 2, CHARACTERIZED by the fact that it also comprises one or more points of field concentration, for concentration of electromagnetic energy in discrete locations.
[0004]
4. Apparatus according to any one of claims 1 to 3, CHARACTERIZED by the fact that the vaporizable substance is water.
[0005]
Apparatus according to any one of claims 1 to 4, CHARACTERIZED by the fact that the apparatus further comprises a means for creating a vacuum within the processing chamber.
[0006]
6. Apparatus according to claim 5, CHARACTERIZED by the fact that the means of creating a vacuum is controlled manually or automatically.
[0007]
7. Apparatus according to any one of claims 1 to 6, CHARACTERIZED by the fact that it also comprises a means for monitoring electromagnetic energy within the processing chamber.
[0008]
8. Apparatus, according to claim 7, CHARACTERIZED by the fact that the means for monitoring electromagnetic energy is controlled manually or automatically.
[0009]
9. Apparatus according to any one of claims 1 to 8, CHARACTERIZED by the fact that it also comprises means for adjusting the electromagnetic energy field strength.
[0010]
10. Apparatus according to claim 9, CHARACTERIZED by the fact that the means for adjusting the electromagnetic energy field strength is controlled manually or automatically.
[0011]
11. Apparatus according to any one of claims 1 to 10, CHARACTERIZED by the fact that the one or more waveguides further comprise lenses for transmitting electromagnetic energy from the waveguides to the material.
[0012]
Apparatus according to any one of claims 1 to 11, CHARACTERIZED by the fact that it additionally comprises means for monitoring the material's surface temperature.
[0013]
13. Apparatus according to any one of claims 1 to 12, CHARACTERIZED by the fact that the apparatus comprises a plurality of wave generators and waveguides.
[0014]
14. Apparatus according to claim 13, CHARACTERIZED by the fact that the plurality of wave generators and waveguides are adapted to provide different intensities of electromagnetic field and / or wave frequencies to the material.
[0015]
15. Apparatus according to claim 13 or 14, CHARACTERIZED by the fact that the plurality of waveguides is arranged linearly and in which the apparatus further includes a conveyor for transporting material for display by each of said waveguides.
[0016]
16. Apparatus according to claim 15, CHARACTERIZED by the fact that the waveguides are arranged below the conveyor.
[0017]
17. Apparatus according to claim 16, CHARACTERIZED by the fact that the carrier comprises one of the lenses or the waveguides.
[0018]
18. Apparatus according to any one of claims 1 to 17, CHARACTERIZED by the fact that it further comprises a condenser to condense the vaporized substance after extraction from the material.
[0019]
19. Apparatus, according to claim 18, CHARACTERIZED by the fact that the condenser is located below the waveguides.
[0020]
20. Apparatus according to claim 19, CHARACTERIZED by the fact that it also comprises a shield between the condenser and the waveguides to prevent electromagnetic energy from contacting the condenser or the condensed substance.
[0021]
21. Apparatus according to any one of claims 15 to 17, CHARACTERIZED by the fact that the carrier comprises a dielectric material.
[0022]
22. Apparatus according to any one of claims 1 to 21, CHARACTERIZED by the fact that the material is one or more of fruits, vegetables, fruit juices, vegetable juices, precooked grains, bacterial cultures, vaccines, enzymes , protein isolates, hydrocolloids, injecting drugs, pharmaceutical drugs, antibiotics, antibodies, meat, fish, seafood, milk, cheese, whey protein isolates, yogurts, fruit extracts, vegetable extracts, or extracts of beef.
[0023]
23. Use of the apparatus as defined in any of claims 1 to 21, CHARACTERIZED by the fact that the apparatus is used in the dehydration of a material containing water.
[0024]
24. Use of the apparatus as defined in any of claims 1 to 21, CHARACTERIZED by the fact that the apparatus is used in the sterilization of a material containing water.
[0025]
25. Use, according to claim 24, CHARACTERIZED by the fact that the processing chamber is pressurized to allow water heating, but to avoid water vaporization.
[0026]
26. System for vaporizing a vaporisable substance from a material, the vaporisable substance being subjected to vaporisation after receiving electromagnetic energy, the system CHARACTERIZED by the fact that it comprises two or more of the apparatus as defined in any one of claims 1 to 21 arranged in series.
[0027]
27. System, according to claim 26, CHARACTERIZED by the fact that the devices of the series are adapted to supply electromagnetic energy of a different frequency and / or intensity of field.
[0028]
28. Method for vaporizing a vaporizable dielectric substance from a material, the vaporizable substance being subjected to vaporization after exposure to microwave energy, the method CHARACTERIZED by the fact that it comprises: - providing a raw material containing the vaporizable dielectric substance ; - introduce the raw material into a processing chamber; - adjust the pressure inside the processing chamber, in which said pressure is monitored and / or controlled manually or automatically; - heat the raw material with microwave energy in the neighboring field range of at least one non-gas dielectric waveguide by evanescently coupling microwave microwave energy that passes through and is confined within at least a waveguide with the material, the microwave energy being sufficient to heat and vaporize the substance, thereby resulting in a treated material in which a portion of the substance was extracted from the raw material; and - removing the treated material from the processing chamber.
[0029]
29. Method according to claim 28, CHARACTERIZED by the fact that at least one non-gas dielectric waveguide is comprised of a solid, semi-solid or liquid material.
[0030]
30. Method according to claim 28 or 29, CHARACTERIZED by the fact that the vaporizable substance is water.
[0031]
31. Method according to any of claims 28 to 30, CHARACTERIZED by the fact that the processing chamber is under vacuum conditions.
[0032]
32. Method according to any one of claims 28 to 31, CHARACTERIZED by the fact that the electromagnetic energy within the processing chamber is monitored and / or controlled manually or automatically.
[0033]
33. Method according to any one of claims 28 to 32, CHARACTERIZED by the fact that the electromagnetic energy field strength is monitored and / or controlled manually or automatically.
[0034]
34. Method according to any one of claims 28 to 33, CHARACTERIZED by the fact that the material is one or more of fruits, vegetables, fruit juices, vegetable juices, precooked grains, bacterial cultures, vaccines, enzymes , protein isolates, hydrocolloids, injecting drugs, pharmaceutical drugs, antibiotics, antibodies, meat, fish, seafood, milk, cheese, whey protein isolates, yogurts, fruit extracts, vegetable extracts, or extracts of beef.
[0035]
35. Method for uniformly heating a material with electromagnetic energy, the method CHARACTERIZED by the fact that it comprises: - supplying a raw material; - introduce the raw material into a processing chamber; - heat the raw material with microwave energy in the neighboring field range of at least one non-gas dielectric waveguide by evanescently coupling microwave microwave energy that passes through at least one waveguide with the material, the microwave energy being sufficient to heat the raw material, thereby resulting in a heated material; and - removing the treated material from the processing chamber.
[0036]
36. The method of claim 35, characterized by the fact that at least one non-gas dielectric waveguide is comprised of a solid, semi-solid or liquid material.
[0037]
37. Method, according to claim 35 or 36, CHARACTERIZED by the fact that the raw material is one or more of fruits, vegetables, fruit juices, vegetable juices, precooked grains, bacterial cultures, vaccines, enzymes, isolates of protein, hydrocolloids, injecting drugs, pharmaceutical drugs, antibiotics, antibodies, meats, fish, seafood, milk, cheese, whey protein isolates, yogurts, fruit extracts, vegetable extracts, or meat extracts.

类似技术:

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同族专利:

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公开号 | 公开日

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RS57683B1|2018-11-30|

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BR112015011291A2|2017-07-11|

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US20150313273A1|2015-11-05|

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DK2920533T3|2018-10-01|

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CL2015001310A1|2015-12-18|

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ES2688125T3|2018-10-31|

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LT2920533T|2018-10-10|

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PL2920533T3|2019-03-29|

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CA2888921A1|2014-05-22|

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EP2920533A1|2015-09-23|

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EP2920533B1|2018-06-20|

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HRP20181492T1|2018-11-16|

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MX2015006089A|2016-03-31|

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SI2920533T1|2018-10-30|

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EP2920533A4|2016-07-06|

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HUE039987T2|2019-02-28|

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PT2920533T|2018-10-22|

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US9585419B2|2017-03-07|

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WO2014075193A1|2014-05-22|

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CA2888921C|2015-08-18|

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CY1121221T1|2020-05-29|

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法律状态:
2018-11-21| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|

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2020-03-24| B06U| Preliminary requirement: requests with searches performed by other patent offices: suspension of the patent application procedure|

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2020-09-24| B09A| Decision: intention to grant|

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2020-12-15| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 18/11/2013, 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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US201261727563P| true| 2012-11-16|2012-11-16|

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US61/727,563|2012-11-16|

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PCT/CA2013/050880|WO2014075193A1|2012-11-16|2013-11-18|Apparatus and method for dehydration using microwave radiation|

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