• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Microwave oven for heating continuous flows of liquids and semisolids. Industrially applicable microwave oven for heating continuous flows of liquids and semisolids, whose resonant cavity has a section with circular arcs that allow the concentration of multimodal microwave radiation in its central axis; where the furnace has metallic cylindrical waveguides to the cut as electromagnetic filters that allow the passage of the hollow dielectric tube and the product to be processed, preventing microwave radiation to the outside, dielectric and/or metallic tuners for the adjustment of the distribution multimodal energy inside the cavity, and lossless dielectric supports; where the microwave energy propagates through a rectangular waveguide powered by a microwave generator system; and wherein said waveguide is short-circuited at the end thereof and communicates with the quasi-cylindrical cavity through slots. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2698150A1
    申请号:ES201831140
    申请日:2018-11-23
    公开日:2019-01-31
    发明作者:Martin Ana Alvarez；Alonso Maria Jose Cocero；Fernandez Jose Fayos；Chain Rafael Bartolome Mato；Cabrera Juan Monzo
    申请人:Universidad de Valladolid；Universidad Politecnica de Cartagena；
    IPC主号:
    专利说明:

    [0001]
    [0002]
    [0003]
    [0004] Field of the invention
    [0005]
    [0006] The present patent consists of a quasi-cylindrical multimode microwave oven for heating continuous flows of liquids and semi-solids with various industrial applications or uses.
    [0007]
    [0008] Although the field of application of the invention is preferably designed for processes of extracting substances for the pharmaceutical or parapharmaceutical industry, it can also be useful in other processes such as: pasteurization of semisolid or liquid agro-food products, enzymatic inactivation of vegetable products such as mushrooms or artichokes, and any other process in which the product can be introduced in a semi-solid or liquid flow for which a rapid temperature rise with a very high efficiency is needed.
    [0009]
    [0010] State of the art
    [0011]
    [0012] It is known that microwave-assisted extraction processes (MAE), or those of inactivation or pasteurization with dielectric heating, have been shown to be much faster and more efficient than conventional homologous processes. Added to this is the fact that the combination of these in a pressurized atmosphere allows this phenomenon to be further accelerated. Generally, microwave assisted extraction is a batch process, confining the substances to be processed in containers such as tubes or tanks in which the reactions take place, as a consequence of the rise in temperature and / or pressure. For example, the reactions in the MAE processing of plant products, cause cell lysis that allows the release of substances of industrial interest such as polyphenols.
    [0013]
    [0014] It is known what is disclosed in various documents such as WO2011048349 and MX2016006872 where different apparatuses are described for treating a product with microwave radiation in monomodal regime, but where their cavities do not have a section configuration rectangular with cylindrical edges that allow a feeding with slotted rectangular waveguide to achieve a multimodal distribution, nor have tuners inside.
    [0015]
    [0016] The document MX2015010222 discloses a microwave heating device with a monomodal tubular waveguide applicator and reactive and resistive filters to reduce leakage, however, as will be seen later, in our invention no resistive filters are used in the applicator Multiple modes coexist that are excited through a grooved waveguide and the section is not tubular but rectangular with the vertices replaced by curved sections.
    [0017]
    [0018] WO9639792 discloses a typology of cylindrical microwave oven, where the diameter of the containment chamber is designed according to a process that contemplates a microwave pattern that substantially contemplates only two transverse magnetic modes and conditioned to the material to be heated being relatively flat and whose loading / unloading is assisted (batch process); however, in the present invention there is a multimodal distribution of energy in a rectangular applicator with the vertices replaced by circular sections and a feed made with a slotted rectangular guide as well as internal metallic tuners and designed for a continuous processing.
    [0019]
    [0020] The disclosure disclosed in EP1176370 discloses a method of heating a flow of mineralized water flowing through a tube of dielectric material, where a part of the section of said tube passes through the central zone of a box with upper and lower areas that they constitute grooved waveguides facing each other, but their application to another material with different dielectric properties, for example varying their mineral composition, would reduce efficiency by not presenting tuning elements and could even damage the microwave source by reflection if a direct exchange were successful of cross energy between the waveguides.
    [0021]
    [0022] In JPS5443346 an electromagnetic induction heating system is disclosed and the Joule effect is produced on a conductive material. The core of said system has a triaxial configuration, constituted by an outer metallic tube that contains an intermediate metal tube with longitudinal or spiral grooves, which in turn contains a central metal bar; while the space between the outer tube and the intermediate tube is free, The material to be heated is circulated between the intermediate tube and the central bar. This system is designed to induce electric currents in the conductive material (which is not dielectric) to be heated, so its design provides for the monomodal irradiation of a homogeneous magnetic field. The coupling of the energy injected through two waveguides to the core of the system is achieved through a non-tunable fixed adapter.
    [0023]
    [0024] The disclosure disclosed in WO2011071933 discloses the heating of fuel circulating through a ceramic pipe partially inserted in a short-circuited waveguide and equipped with in-line tuners up to% wavelength -configurable in a triple stage of up to 1 wavelength - to properly couple the mode of energy injected into the single-mode waveguide. While it could be considered that the use of tuners is anticipated in this document, the detailed configuration in the document is only feasible in structures where the energy pattern has a monomodal distribution, while the present invention the energy distribution responds to a multimodal pattern.
    [0025]
    [0026] Document JP2014000070A provides a series of dielectric tubes through which the liquid to be treated circulates perpendicularly through a rectangular waveguide short-circuited at its end by a mobile metal wall that allows its tuning, valid for a single-mode regime. Said document also contemplates that the dielectric tubes are sheathed in slotted metal tubes in the manner of windows whose function is to uncouple the individual influence of each tube on the assembly and facilitate the distribution of the energy homogeneously between the different tubes.
    [0027]
    [0028] Taking into account these aspects, none of the documents belonging to the state of the art has a configuration where the geometry of the cavity has a flat surface that allows coupling a grooved waveguide to excite multiple modes and achieve a good efficiency and stability, nor to arrange a centered cylindrical dielectric tube to contain and transport the material under thermal treatment with anchors that give it mechanical strength against possible deformations caused by pressure increases and dilatations during processing, or include a transport system by means of pumps or screws endless to control the flow of the product to be processed. The high efficiency of the industrial application is achieved thanks to the quasi-cylindrical configuration of the microwave irradiation cavity, with a rectangular section whose vertices are smoothed in the form of a circular arc, which allows the introduction of all necessary subsystems synergistically to achieve optimized processing of very high efficiency and versatility for different liquid or semi-solid materials, which are not integrable simultaneously with the limitations in the designs of furnaces known in the state of the art.
    [0029]
    [0030] In view of the solutions and background existing in the state of the art, the present invention describes a configuration of microwave oven, not as an independent and simple composition of elements such as generators coupled to containers, but as an integral solution supported by a cavity of Quasi-cylindrical section that allows the simultaneous effective functional arrangement and synergy of various subsystems in its interior with which it is possible to excite multiple modes, and achieve a good level of efficiency, stability and versatility to heat liquid or semi-solid materials with a wide range of dielectric properties , having a cylindrical dielectric tube through which the material under treatment flows continuously through the core of the cavity and anchored by supports that give it mechanical strength by allowing it to contain the mechanical expansion produced in its interior due to the elevation of temp erature of its content, electromagnetic filters that prevent the leakage of microwaves to the outside of the cavity, as well as a grooved waveguide for the multimodal feeding of the applicator, tuning elements, and the inclusion of a transport system by means of pumps or screws endless to control the flow of the transport of the material to be processed, which is not possible to obtain with the antecedents alone or in combination, unless they are included or implemented with other accessory elements not contemplated in said documents.
    [0031]
    [0032] Description of the invention
    [0033]
    [0034] The present invention consists of a microwave oven or applicator with a rectangular two-dimensional section, preferably a prism with a rectangular base in the three-dimensional space, and with its vertices finished in a circular shape, so that it constitutes a section defined by rectangular and circular sections at replace the corners (edges in the three-dimensional perspective) of the rectangular section with circular arcs, thus having a cavity or microwave irradiation chamber with a quasi-cylindrical section.
    [0035] This geometry allows to have segments of flat walls in the central parts of the section where slotted rectangular waveguides can be coupled to excite multiple modes and achieve greater efficiencies and stability in the operation of the oven to heat in a versatile way multiple formulations and products. It also allows the furnace to comprise a cylindrical dielectric tube through which the material under treatment flows centered inside the furnace by means of supports anchored to the cavity that give it mechanical strength by allowing it to contain the mechanical expansion produced in its interior due to the elevation of its contents temperature.
    [0036]
    [0037] The semi-cylindrical geometry of the section allows directing the microwave energy towards the central axis of symmetry where the dielectric tube and the material to be heated are located, independently of the excited mode, which implies a greater efficiency than a multimode oven with rectangular section and, it manages to avoid the impossibility of using conventional grooved waveguides to feed the cylindrical applicators. This is achieved with circular arcs, which conveniently replace the vertices of the rectangular section. This effect of increasing energy efficiency has not been read in any type of scientific document or in any previously patented document.
    [0038]
    [0039] The multimodal configuration of this cavity, likewise, allows to have different heating patterns inside the dielectric tube so that this heating is much more uniform than that achieved by a single-mode pattern, which allows to process larger volumes of materials than those that are possible a single mode cavity.
    [0040]
    [0041] Likewise, metallic cylindrical guides to the cut are attached to the walls that act as short circuits of the waveguide and which, together with it, make up the microwave cavity. These cylindrical guides to the cut allow the injection / extraction of the material to / from the cavity in a continuous way through the dielectric tube without microwave leakage beyond the limits marked by the applicable legislation in each place of location where exploit the present invention.
    [0042]
    [0043] Among other aspects, the present invention can include metal cylinders or tuning dielectrics in one of the metallic walls anchored in the multimodal electromagnetic pattern that improve its energy efficiency and / or the uniformity of heating inside the furnace.
    [0044] The furnace includes a transport system so that the material to be treated circulates through the tube according to the required speed with the help of endless screws that allow the advance of the material, or through the use of pumps coupled to the dielectric tube by means of auxiliary tubes. or hoses.
    [0045]
    [0046] In this way, the present configuration allows the furnace to be incorporated into different production systems, such as, for example, a microwave-assisted extraction system for chemical products from vegetable or animal products mixed with a solvent or introduced in the raw (without solvent); a system for microwave pasteurization or sterilization for semi-solid or liquid foods; or a system for the enzymatic inactivation by microwaves of different vegetable products.
    [0047]
    [0048] The product to be processed can be in liquid, semi-solid state or as mixtures of solvents and solid products, but in any case it is a product that can be driven through a hollow dielectric tube, for example, of quartz borosilicate, PTFE (polytetrafluoroethylene ) or PEEK (polyetheretherketone), either with pumps or with other driving methods such as endless screws.
    [0049]
    [0050] The microwave oven, as advanced, has a quasi-cylindrical shape in which the vertices of the rectangular section are smoothed in a curve. In this way the vertices are replaced by 90 ° circular arcs and the section can be described as a hybrid between a square and a circular section, referred to herein as a quasi-cylindrical section. This allows to advantageously include, compared to the direct insertion of the antenna of a magnetron inside the cavity, a power supply radiated through a rectangular guide slotted in one of the flat walls of the applicator, enabling the removal of the proximity of the magnetron antenna to the dielectric tube, which prevents the appearance of harmful electric arcs, and the use of wave-coaxial guide adapters between the magnetron and the cavity, allows the simultaneous excitation of multiple modes to achieve greater degrees of homogeneity of heating.
    [0051]
    [0052] The grooved waveguide is shorted at both ends, inserting the magnetron antenna that energizes it into one of the extreme short-circuits (line coupling) or at a distance of% wavelength thereof (electrical plane coupling), forcing that the microwaves radiate through the slots. This grooved waveguide works preferentially in single mode configuration which facilitates its design and construction.
    [0053]
    [0054] The furnace has metal tuners and / or dielectrics in some of the metal walls, which can be in the form of screws or pivots, which when inserted allow modifying the patterns of the resonant modes inside the cavity in order to improve the efficiency of the heating and / or its uniformity. Since the design of the furnace allows its scalability by cascading different modules for a multistage processing, the tuners can be adjusted conveniently in each stage since the material will change its dielectric properties as its temperature changes and / or its processing evolves.
    [0055]
    [0056] To confer mechanical strength to the dielectric tube that prevents its deformation (combamientos) due to pressures exerted from its interior due to the generation of gaseous byproducts such as the evaporation of water from the material in processing and the stresses inherent to the expansion of materials according to the temperature, the hollow dielectric tube is passed through a series of blocks of dielectric material without losses that act as a support anchored to the furnace walls and arranged along its axial axis.
    [0057]
    [0058] As for the operating process of the oven, the product to be processed, for example, grape marc dissolved in ethanol, is driven through the dielectric tube gap by means of a pump that allows its flow, variable or constant. The product passes inside a cylindrical waveguide to the cut that contains both the product to be processed and the dielectric hollow tube, and in this way, the product can pass inside the applicator without the microwave radiation escaping its confinement towards the outside of the applicator.
    [0059]
    [0060] Once inside the applicator, the product is centered on the axis of symmetry of the applicator thanks to the dielectric supports. The magnetron or microwave source radiates through the grooved waveguide that connects to the quasi-cylindrical cavity through openings or slots. The microwave energy propagates through this waveguide until it reaches these openings through which it is transferred to the quasi-cylindrical cavity. Each of the slots transfers part of the energy that propagates through the waveguide, so that it is transferred in a distributed manner between all the slots. This causes the excitation of several resonant modes in the quasi-cylindrical cavity, where each mode concentrates its Maximum electric field strengths in certain locations according to their electromagnetic pattern, causing the temperature increase in different subvolumes of the material to be processed. In this way, the entire magnetron bandwidth can be covered with great efficiency and at the same time a good distribution of the heating pattern can be obtained, with high homogeneity indexes. The proper design of the slots can both increase the energy efficiency of the oven and achieve better microwave heating distributions.
    [0061]
    [0062] The heating is also volumetrically uniformized by the fact that the gases generated during the process, mainly water vapor, are redistributed reaching the entire volume of the interior of the dielectric tube, diffusing radially and longitudinally by convective currents conditioned by possible thermal gradients. In addition, the linear displacement of the material and the turbulences produced both by the displacement and by the effects of the processing, facilitate the thermodynamic mechanisms that propitiate a thermal homogenization.
    [0063]
    [0064] With the increase in temperature and the generation of gases such as water vapor, mechanical stresses may arise in the dielectric tube, so it is convenient that the thickness of the tubular wall is sufficient to contain possible dilatations and internal pressures. The mechanical robustness is complemented with the insertion of additional supports of dielectric material (for example, PTFE) placed inside the quasi-cylindrical cavity.
    [0065]
    [0066] Since the cavity is of multimode type, it can support a large variety of materials to be processed as long as they have sufficient dielectric losses, without losing significant performance in terms of efficiency, which can typically range between 95% and 98%.
    [0067]
    [0068] The materials to be processed to achieve these efficiencies must be within the range of dielectric constant of 50 to 80 at the frequency of the microwaves used (for example 2.45 GHz), and in a range of 17 to 50 with respect to the factor of dielectric losses, although through the correct positioning of the tuners could be processed more materials whose dielectric properties exceed these ranges. To maintain this efficiency with materials with lower dielectric losses, cavities with the same configuration could be made, although adjusting the dimensions to allow the microwaves dissipate in a larger volume.
    [0069]
    [0070] In general, given an industrial application, the processing of the material will require that it remain at a target temperature for a certain time. Consequently, if a single module could not meet these requirements once adjusted the material flow rate, the electromagnetic power used or any other reason, the linear concatenation of several modules is possible by adjusting the power and tuning elements of each module. they according to the operating conditions of each stage.
    [0071]
    [0072] The tuning elements can be made of dielectric material instead of a metallic material or as combinations of both types of materials.
    [0073]
    [0074] The position of the tuners, metallic and / or dielectric, may be anchored in any wall of the applicator, preferably where the grooved waveguide is not coupled.
    [0075]
    [0076] In a preferred embodiment of this invention we have opted for a total symmetry of the section, starting from a square to which the vertices are softened with circular sections, but it has also been found that it is possible to start from a rectangular section instead of a square one. obtaining similar results, or that the softening of the vertices is done by elliptical curves.
    [0077]
    [0078] In other configurations where it is foreseen that the mechanical stresses produced in the dielectric tube are reduced, it is possible to choose to have dielectric fastening posts only in the lower part of the cavity, or in the upper part in the form of hooks, although preferably keeping a certain degree of symmetry.
    [0079]
    [0080] This furnace is applicable in efficient processes of sterilization, pasteurization or enzymatic inactivation, since it allows heating with high uniformity indexes at temperatures above 100 ° C. In the case of sterilization and pasteurization processes, it is necessary to raise and maintain the temperature of a liquid or food product up to a temperature higher than 100 ° C the time necessary to neutralize the harmful micro-organisms of the product and guarantee the period of product preservation during the weeks or months required; in enzymatic inactivation processes, the Product temperature should rise between 80 and 100 ° C
    [0081]
    [0082] It should be taken into account that, throughout the description and the claims, the term "comprises" and its variants do not intend to exclude other technical characteristics or additional elements. Furthermore, in order to complete the description and to help a better understanding of the characteristics of the invention, a set of figures and drawings is presented wherein, with illustrative and non-limiting character, the following is represented:
    [0083]
    [0084] Fig.1.- Shows a perspective view of the furnace object of the present invention.
    [0085]
    [0086] Fig.2.- Shows a cross section of the furnace object of the present invention.
    [0087]
    [0088] Taking into account the figures, it can be said that the present invention proposes a microwave oven (1) of industrial application for the extraction of chemical substances, food pasteurization or enzymatic inactivation, with a section of rectangular type in which its vertices are replaced by circular arcs (3) so that said section is the hybridization of circular and rectangular sections, or a quasi-cylindrical configuration (2), said applicator containing a hollow cylindrical dielectric tube (4) (5) that allows the passage of the product to be treated and whose tubular walls have enough thickness to contain the pressure inside during the processing of the product. The furnace also contains at least two metallic cylindrical waveguides (8) to the cut that together allow the passage of the dielectric tube (4) and the product to be processed avoiding the microwave radiation to the outside, dielectric tuners (11) and / or metallic, typically cylindrical, and lossless dielectric supports (12) to maintain the hollow dielectric tube in the axis of symmetry of the applicator. The microwave feed is produced through a rectangular waveguide (8) that is connected to a microwave generator system, preferably a magnetron. The feed waveguide (8) is short-circuited at the end thereof and electromagnetically coupled to the quasi-cylindrical cavity through slots (10) which are preferably positioned inclined to the direction of propagation of the fundamental mode of the guide Wave (8). Finally, to avoid leakage of energy to the outside, the segments of dielectric tube (4) protruding from the oven on both sides are coated or have around them electromagnetic filters that are hollow metal tubes (6a-6b).
    [0089] Detailed description of a preferred embodiment of the invention
    [0090]
    [0091] A preferred embodiment of the invention for an operation in the ISM band of 2.45 GHz applicable to the industrial field is similar to that proposed in figure 1 and consists of a cavity or quasi-cylindrical metallic structure where the maximum height and width are same and they are in the range 16 to 20 cm and their maximum length is in the range of 50 to 60 cm. The vertices of the rectangular section are replaced by circular arcs with an angle between 80 and 90 ° and a radius between 4 and 5 cm.
    [0092]
    [0093] A PTFE tube (polytetrafluoroethylene, commonly called Teflon) is used with an external radius that can vary between 2.5 and 3.5 cm and an internal radius between 1.5 and 2 cm. The PTFE tube has a length between 60 and 70 cm.
    [0094]
    [0095] The cylindrical wave guides to the cut are adjusted to the outer radius of the PTFE tube and therefore have an internal radius between 2.5 and 3.5 cm. The cylindrical waveguides have a length between 5 and 10 cm.
    [0096]
    [0097] The rectangular waveguide is placed in the upper part of the cavity on the flat part of the upper wall as shown in figure 1. The length of the waveguide covers the entire upper wall of the quasi-cylindrical cavity and protrudes at least a distance of 2 to 5 cm from it to allow the fixation of the magnetron and insert its antenna inside the waveguide. The dimensions of the section of the waveguide in this case are those of the standard WR-340, that is, 4.3 cm x 8.6 cm.
    [0098]
    [0099] The slots that communicate the upper wave guide with the quasi-cylindrical lower cavity have a maximum length that varies between 5 and 8 cm and a width that varies between 2 and 3.5 cm. The orientation (inclination) of the longitudinal axis of the slots can present a rotation between 20 and 90 degrees with respect to the direction of propagation of the electromagnetic wave inside the waveguide, and the separation between slots can be between 4 and 6 cm . The number of slots can be between 10 and 15. In this preferred embodiment, it is decided to make all the slots with the same dimensions and inclination although they could be of increasing dimensions to radiate a similar power in each of them or have different inclinations and separations.
    [0100] The magnetron is placed preferably at the end where the material enters the cavity, since it is when it will present greater dielectric losses during processing (due to being at a lower temperature, higher water content, etc.), enabling the material to absorb the higher powers that can be irradiated by the slots closest to the magnetron, the slots being furthest away having the lowest electromagnetic power and conveniently reducing the risk of electric arc due to the decrease in the loss factor, or the increase in temperature, dehydration and / or others. The number of supports of the dielectric tube, made of PTFE, and placed inside the quasi-cylindrical cavity ranges between 3 and 7, with dimensions that cover the entire width of said cavity and are smaller in their height to avoid hinder the radiation of the slots. In this configuration, the supports are made by a solid of rectangular section with a circular central hole that fits perfectly to the PTFE dielectric tube. In this preferred embodiment the supports would have a maximum width between 16 and 20 cm and the maximum height would be between 8 and 10 cm. The thickness of the supports would be in a range of 1 to 3 cm.
    [0101]
    [0102] Finally, in this preferred embodiment, between 4 and 8 metal tuners can be included, for example, steel, although they could also be dielectrics, with a radius of between 1 and 1.5 cm and a height within the maximum cavity between 3 and 5 cm. In this preferred embodiment, the tuners are screws with these maximum dimensions and threaded to the structure of the quasi-cylindrical cavity at its lower part, on the side opposite to that which contains the grooved waveguide, as shown in FIG. Figure 1. The spacing between tuners can vary between 7 to 12 cm.
    [0103]
    [0104] Detailed description of the drawings
    [0105]
    [0106] Figure 1 shows the preferred embodiment of the invention described herein, where the microwave oven or applicator consists of a metal cavity (1) with quasi-cylindrical section (2), which is composed of a rectangular section in which the vertices are replaced by circular arcs (3) of 90 ° and a suitable radius. Said cavity ends at both ends with two metal plates that preserve said quasi-cylindrical section and to which a cylindrical opening is made to attach a cylindrical metallic guide (8) to the cut, which allows the passage of a dielectric tube. (4) hollow (5) manufactured with a low loss material. The thickness of the dielectric tube (4) is such that Holds the pressures exerted by the steam generated by heating the material by microwaves and, in turn, allows the proper passage of the material to be processed.
    [0107]
    [0108] The material is driven by pumps or other mechanisms that push it linearly or by pulses through the gap of the dielectric tube (4). The linear or effective speed at which the material to be treated is driven will depend on the temperature and pressure to be reached inside the quasi-cylindrical applicator.
    [0109]
    [0110] Additionally the invention presents electromagnetic filters which are metallic hollow tubes (6a-6b) which are arranged around the segments of dielectric tube (4) projecting from the furnace during the reduced length and which prevent the leakage of energy to the outside.
    [0111]
    [0112] The excitation of the modes of this quasi-cylindrical cavity is carried out through a rectangular metallic waveguide (8) having grooves (10) coinciding with the upper wall of this cavity. The feeding of the magnetron to the guide is produced by one of the ends of the waveguide, which can be referred to as the initial end (7), while the other end of the waveguide is short-circuited by a perpendicular metal (9). ) to the propagation direction of the fundamental mode of the waveguide (8), in this case on a rectangular waveguide.
    [0113]
    [0114] The grooves (10) are made in this case by rectangular openings on the upper metal wall of the quasi-cylindrical cavity and with an orientation rotated between 30 and 50 °, preferably 40 °, on the direction of propagation of the fundamental mode of the guide.
    [0115]
    [0116] Inside the quasi-cylindrical cavity, in this case in the lower wall, metallic tuners (11) are inserted, which are screwed to the metallic bottom wall of the cavity. These tuners are introduced to a greater or lesser extent, and depending on the number available, its volume and said penetration in the furnace, can change or alter the resonance frequency of its different modes and / or the field distribution inside of the quasi-cylindrical cavity to achieve greater efficiency or heating uniformity.
    [0117]
    [0118] Likewise, supports (12) of dielectric material without losses are introduced which allow the tube to be held inside the cavity and that reinforce the tube against the internal pressures it may suffer. In this case the supports (12) are configured as blocks of rectangular section with a circular opening to allow the passage of the dielectric tube. The blocks cover the cavity in its entire width so that they can be anchored to their side walls, for example, with dielectric screws, but they do not fill in height the entire section.
    [0119]
    [0120] Figure 2 shows a section of the furnace where the quasi-cylindrical section (2) of the resonant cavity is observed in which the vertices of the rectangular section are replaced by circular arcs (3). The figure also shows front views of the waveguide (4), the dielectric tube (4) passing through its interior and the central hole or hole (5) of cylindrical air through which the material moves. At the top is the front view of the rectangular waveguide (8), and more specifically, the final short-circuit of this waveguide. Additionally, a front view of one of the tuners (11) and of a support (12) is observed, in this case a clamping block, which is inside the quasi-cylindrical microwave cavity.
    权利要求:
    Claims (11)
    [1]
    1. - Multimode microwave oven for heating continuous flows of liquids and semisolids, where the microwave oven (1) has a rectangular section (2) in which the vertices of said section are replaced by circular arcs (3) so that said section is the combination of circular and rectangular sections, generating a cavity or quasi-cylindrical structure and that allows to preferentially direct the electromagnetic radiation towards its axis of symmetry independently of the excited mode; it comprises inside it a hollow dielectric tube (4) (5) where the material is treated; and where the excitation of the modes of this quasi-cylindrical structure is carried out through a metallic wave guide (8) located in an external position with respect to the quasi-cylindrical structure of the oven, which has grooves (10) coinciding with the wall of the quasi-cylindrical structure, and where said waveguide (8) is connected to a microwave generating system; and that is characterized by:
    - the waveguide (8) is connected to the microwave generator system at an initial end (7) thereof, while the other end of the waveguide (8) is short-circuited by a metal perpendicular (9) to the direction of propagation;
    - it has a drive means for the material to be treated to circulate under pressure through the gap (5) contained in the dielectric tube (4);
    - presents electromagnetic filters which are metallic hollow tubes (6a-6b) which are arranged around the segments of dielectric tube (4) projecting from the furnace and which prevent the leakage of energy to the exterior;
    - the grooves (10) are positioned inclined to the direction of propagation of the fundamental mode of the waveguide (8);
    - further comprises a plurality of lossless dielectric supports (12) that maintain the dielectric tube (4) in the central axis of symmetry of the furnace; and a plurality of cylindrical tuners (11), which are anchored to the internal wall of the quasi-cylindrical structure, which depending on the number available, its volume and penetration in the furnace alter the resonance frequency inside it .
    [2]
    2. - Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the height and width of the quasi-cylindrical metal structure are equal.
    [3]
    3. - Microwave oven for heating continuous flows of liquids and semisolids, according to claim 1, characterized in that the drive means are pumps.
    [4]
    4. Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the drive means are endless screws.
    [5]
    5. - Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the microwave generating system is a magnetron.
    [6]
    6. - Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the angle of rotation or inclination of the grooves (10) is between 30 and 50 °.
    [7]
    7. - Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the tuners (11) are metallic.
    [8]
    8. Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the tuners (11) are dielectric.
    [9]
    9. - Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the tube (4) is made of PTFE (polytetrafluoroethylene), PEEK (polyetherreeketone) or quartz borosilicate.
    [10]
    10. - Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the plurality of supports (12) are PTFE, PEEK or quartz borosilicate.
    [11]
    11.- Microwave oven for heating continuous flows of liquids and semi-solids, according to claim 1, characterized in that the supports (12) are configured as blocks of rectangular section with a circular opening that allows the passage of the dielectric tube ( 4), and cover the entire width of the furnace structure to anchor to its side walls.
    类似技术:
    公开号 | 公开日 | 专利标题
    US4922180A|1990-05-01|Controlled microwave sample irradiation system
    ES2282862T3|2007-10-16|MICROWAVE RESONATOR, A TREATMENT CHAIN MODULARLY BUILT FROM A MICROWAVE RESONATOR OF THIS TYPE, AN OPERATIONAL PROCEDURE AND OBJECTS / PARTS TO BE PROCESSED THERMALLY ACCORDING TO THIS PROCEDURE THROUGH MICROWAVE.
    US6163020A|2000-12-19|Furnace for the high-temperature processing of materials with a low dielectric loss factor
    ES2698150A1|2019-01-31|MICROWAVE OVEN FOR THE HEATING OF CONTINUOUS LIQUID AND SEMI-SOLID FLOWS |
    ES2621813T3|2017-07-05|Apparatus for reducing and eliminating local areas of overheating in sensitive loads of dielectric materials
    US6863773B1|2005-03-08|Linearly extended device for large-surface microwave treatment and for large surface plasma production
    US20030205574A1|2003-11-06|Microwave system for heating voluminous elongated loads
    ES2710670T3|2019-04-26|Device for applying electromagnetic energy to a reactive medium
    ES2256546T3|2006-07-16|APPARATUS FOR HEATING BY MICROWAVE.
    JPWO2013005438A1|2015-02-23|microwave heating device
    US3446929A|1969-05-27|Microwave apparatus
    ES2674883T3|2018-07-04|Electromagnetic radiation treatment apparatus of a reactive medium
    US20090032528A1|2009-02-05|Microwave heating applicator
    CN101697650B|2011-11-30|Resonant ceramic shimming plate used for microwave heating device
    US7462978B1|2008-12-09|Apparatus and method for generating ultraviolet radiation
    KR101383626B1|2014-04-10|Slots-excited Racetrack ECR Plasma Source for Roll-to-roll| Processing
    RU2203459C1|2003-04-27|Vacuum freeze drying unit
    RU156462U1|2015-11-10|DEVICE FOR MICROWAVE HEATING OF DIELECTRIC MATERIALS
    RU2125350C1|1999-01-20|Microwave absorbing chamber
    RU2203597C1|2003-05-10|Vacuum sublimation drying apparatus
    RU2200921C1|2003-03-20|Method of sublimation drying
    CN104470020A|2015-03-25|Microwave heating and drying device
    RU2203460C1|2003-04-27|Vacuum freeze drying unit
    KR20020004803A|2002-01-16|A cancer thermotherapy
    RU2572033C1|2015-12-27|Method of cereal products processing and device to this end
    同族专利:
    公开号 | 公开日
    ES2698150B2|2019-05-17|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPS5443346A|1977-09-12|1979-04-05|Mitsubishi Electric Corp|High frequency heating apparatus|
    EP1176370A2|2000-07-28|2002-01-30|Masakazu Matuo|Continuous flow type heating apparatus|
    CN2801162Y|2005-06-08|2006-08-02|於洪平|Micro-wave drying sterilising apparatus|
    WO2011071933A1|2009-12-07|2011-06-16|Novak John F|Method and apparatus for microwave-based liquid vaporization system|
    JP2014000070A|2012-06-20|2014-01-09|Blue Oceans:Kk|Device for normal temperature sterilization|
    法律状态:
    2019-01-31| BA2A| Patent application published|Ref document number: 2698150 Country of ref document: ES Kind code of ref document: A1 Effective date: 20190131 |
    2019-05-17| FG2A| Definitive protection|Ref document number: 2698150 Country of ref document: ES Kind code of ref document: B2 Effective date: 20190517 |
    优先权:
    申请号 | 申请日 | 专利标题
    ES201831140A|ES2698150B2|2018-11-23|2018-11-23|MICROWAVE OVEN FOR THE HEATING OF CONTINUOUS FLOWS OF LIQUIDS AND SEMISOLIDS|ES201831140A| ES2698150B2|2018-11-23|2018-11-23|MICROWAVE OVEN FOR THE HEATING OF CONTINUOUS FLOWS OF LIQUIDS AND SEMISOLIDS|
    [返回顶部]