CN112512154B - Device and method for improving microwave heating efficiency - Google Patents
Device and method for improving microwave heating efficiency Download PDFInfo
- Publication number
- CN112512154B CN112512154B CN202011422828.8A CN202011422828A CN112512154B CN 112512154 B CN112512154 B CN 112512154B CN 202011422828 A CN202011422828 A CN 202011422828A CN 112512154 B CN112512154 B CN 112512154B
- Authority
- CN
- China
- Prior art keywords
- structure layer
- metamaterial structure
- metal shell
- heated space
- heated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/6402—Aspects relating to the microwave cavity
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Constitution Of High-Frequency Heating (AREA)
Abstract
The invention discloses a device and a method for improving microwave heating efficiency, belonging to the technical field of microwave application and comprising a metal shell; a feed port is formed in the metal shell; the feed port is used for inputting microwaves into the metal shell; a metamaterial structure layer is arranged inside the metal shell; a heated space is arranged in the center of the metamaterial structure layer; the relative dielectric constant of the metamaterial structure layer gradually increases from outside to inside, so that the microwaves passing through the metamaterial structure layer are collected in the heated space. The device and the method for improving the microwave heating efficiency can concentrate the microwave energy input into the metal shell into the heated space, and have the advantages of high heating speed and high energy utilization rate.
Description
Technical Field
The invention belongs to the technical field of microwave application, and particularly relates to a device and a method for improving microwave heating efficiency.
Background
Microwave heating is a new type of heating method. When a polar medium is placed in an electromagnetic field, polar molecules forming the medium material are rearranged along with the direction of the constantly changing high-frequency electric field, and the original thermal motion of the molecules and the interference and obstruction among the molecules need to be overcome in the rearrangement process, which is similar to the friction effect, so that a large amount of heat is generated. The microwave heating process is that microwave energy directly acts on a heated substance, is a cold and heat source and is greatly different from the traditional mode of heat transfer by a medium surface.
During microwave heating, the shape, position and shape of the material can cause the change of the electromagnetic field distribution in the cavity, and the thermal physical and electrical physical properties such as material density, heat capacity, dielectric property, heat conductivity and the like in the microwave heating process all dynamically change along with the difference of temperature or water content, so that the microwave energy utilization rate in the whole heating process is low, and the problem of uneven temperature distribution exists.
In the prior art, the uniformity of microwave heating is improved by dynamically changing the frequency of input microwaves and reducing hot spots; and a proper model structure is optimally designed by analyzing the length, width and height of the cavity, the placement position of the port and the influence of the shape of the load on the energy utilization rate, so that the microwave heating uniformity and the energy utilization rate are improved. In a conventional mode, impedance is adjusted through a three-pin tuner, so that the microwave heating system is in an impedance matching state, reflection of microwave energy is reduced, and an object to be heated continuously and efficiently absorbs the microwave energy.
But the microwave energy can still be efficiently absorbed and utilized when the parameters are dynamically changed in a large range, and the method has important significance for the improvement of the microwave energy efficiency and even industrial application.
Disclosure of Invention
The invention aims to provide a device and a method for improving microwave heating efficiency aiming at the defects, and aims to solve the problems of concentrating energy of microwaves to a medium area to be heated, reducing reflection, improving energy utilization rate, efficiently absorbing and utilizing microwave energy and the like. In order to achieve the purpose, the invention provides the following technical scheme:
a device for improving microwave heating efficiency comprises a metal shell 1; a feed port 2 is arranged on the metal shell 1; the feed port 2 is used for inputting microwaves into the metal shell 1; a metamaterial structure layer 3 is arranged inside the metal shell 1; a heated space 4 is arranged in the center of the metamaterial structure layer 3; the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, so that the microwaves passing through the metamaterial structure layer 3 are collected in the heated space 4. According to the structure, the microwave source inputs microwaves to the feed port 2, the microwaves are collected in the heated space 4 after entering the metal shell 1 and passing through the metamaterial structural layer 3, the collected microwaves are continuously absorbed by the heated object in the heated space 4, the microwaves can only enter the special structure of the metamaterial structural layer 3, the reflection in the metal shell 1 is reduced, the utilization rate of the microwave energy is improved, the energy density is high, and the heated object can efficiently absorb and utilize the microwave energy. Due to the characteristics of the metamaterial structure layer 3, the collection of microwaves in the heated space 4 is not affected by the position of the feed port 2, the shape of the metal shell 1 and the parameter change of the heated object, and the heated object can still absorb and utilize the microwave energy efficiently. The metamaterial structure layer 3 can realize that the microwave only enters but not exits because the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, the increasing can be continuous, smooth and gradually increasing or stepped gradually increasing, namely, the relative dielectric constant of the outermost material part of the metamaterial structure layer 3 is minimum, the relative dielectric constant of the innermost material part of the metamaterial structure layer 3 is maximum, the principle of the metamaterial structure layer is similar to that the microwave passes through the metamaterial structure layer 3 and is continuously refracted to the heated space 4, and the microwave only enters the heated space 4 and cannot escape when passing through the metamaterial structure layer 3.
Further, the metamaterial structure layer 3 includesDrying ring columns 5 which are sequentially nested from inside to outside; the heated space 4 is a cylindrical space with a radius r; the radius of the metamaterial structure layer 3 is R; the relative dielectric constant of the space outside the metamaterial structure layer 3 is epsilon0(ii) a The relative dielectric constants of all position points of the metamaterial structure layer 3 form a step function, the distance between each position point and the center of the heated space 4 is d, wherein R is more than d and more than R; each step of the step function and the additionally constructed function epsilon (d) ∈ epsilon0(R/d)2And (4) intersecting. As can be seen from the above-described structure, in the conventional theory, the metamaterial structure layer 3 collects the microwaves into the heated space 4, and the relative dielectric constant of the material is approximated by the function ∈ (d) ∈ (e) —0(R/d)2Namely, the relative dielectric constants of each metamaterial structure layer 3 and the heated space 4 at different axial positions are different. Since air is arranged between the metamaterial structure layer 3 and the metal shell 1, epsilon0Is the relative dielectric constant of air; in practice, however, such a structure is difficult to realize, and the metamaterial structure layer 3 is formed by using a plurality of ring pillars 5 which are nested from inside to outside, so that the relative dielectric constant of the ring pillars 5 at corresponding positions is only required to be approximate to a function epsilon (d) ═ epsilon0(R/d)2The metamaterial structure layer 3 with gradually increased relative dielectric constant of the materials from outside to inside can be formed. For example, if the inner diameter of a certain ring column 5 is d1 and the outer diameter is d2, the relative dielectric constant of the ring column 5 is adopted for the position points which are separated from the axial center of the heated space 4 by the interval of d 1-d 2, so that the relative dielectric constant and the position points of all the ring columns 5 are presented as a step function on the coordinate system. Only each step of the step function and the additionally constructed function epsilon (d) need to be equal to epsilon0(R/d)2Intersecting, i.e. reaching the sum function e (d) e0(R/d)2The purpose of the approach is to collect the microwave. For example, the annular column 5 has an inner diameter d1, an outer diameter d2, a relative dielectric constant e 1, and a horizontal line segment whose abscissa is d1 to d2 and whose ordinate is e 1, and the sum of the horizontal line segment and the function e (d) is e 10(R/d)2And (4) intersecting. The plurality of ring columns 5 nested from inside to outside in sequence comprise a virtual nesting, for example, a material whole with gradually changed relative dielectric constant can be regarded as a virtual nesting from inside to outside in sequenceThe nested ring column 5 is actually a whole material, and the virtual nesting is also included in the nesting concept protected by the invention, so that the processing is convenient and the cost is reduced.
Furthermore, a plurality of hollow cavities 6 are arranged on the ring column 5; two ends of the hollow cavity 6 respectively extend to the top bottom surface of the corresponding ring column 5. According to the structure, the ring column 5 can adopt polyvinylidene fluoride as a base material, and the relative dielectric constant of the ring column 5 can be changed by arranging the hollow cavity 6 on the ring column 5. Calculation and experimental verification can be carried out through the existing theory.
Further, the cross section of the hollow cavity 6 of the outer ring column 5 is larger than the cross section of the hollow cavity 6 of the inner ring column 5. As can be seen from the above structure, the larger the cross section of the hollow cavity 6, the smaller the relative dielectric constant of the ring pillar 5, and the smaller the cross section of the hollow cavity 6, the larger the relative dielectric constant of the ring pillar 5. The section of the hollow cavity 6 of the inner ring column 5 from the outside is smaller and smaller, and the relative dielectric constant of the metamaterial structure layer 3 gradually increases from the outside to the inside.
Further, the hollow cavities 6 on the ring column 5 are uniformly spaced; the number of hollow cavities 6 in each ring post 5 is equal. As can be seen from the above structure, the microwaves enter the metamaterial structure layer 3 from a plurality of angles except the axial direction of the metamaterial structure layer 3, and can be collected in the heated space 4.
Further, the cross section of the hollow cavity 6 is circular, oval or polygonal. From the above structure, the hollow cavity 6 can adopt various cross-sectional shapes to change the relative dielectric constant of the ring pillar 5, and conventionally can adopt a cross-section of a circle.
Further, an opening 7 is formed in the top of the metal shell 1; a gland 8 is arranged on the opening 7; the bottom of the gland 8 is provided with a concave circular groove 9; the concave circular groove 9 is matched at the top of the metamaterial structure layer 3; the metamaterial structural layer 3 is sandwiched between the gland 8 and the bottom of the metal shell 1. According to the structure, the concave circular groove 9 is matched with the top of the metamaterial structure layer 3, so that the metamaterial structure layer 3 is clamped between the gland 8 and the bottom of the metal shell 1, no gap exists at the bottom of the top of the metamaterial structure layer 3, and the microwave is prevented from escaping from the heated space 4.
Further, a communicating cavity 10 is arranged inside the gland 8; the concave circular groove 9 is provided with a plurality of micropores 11; the micropores 11 enable all the hollow cavities 6 and the heated spaces 4 to be communicated with the communication cavity 10 respectively; a safety valve 12 is arranged on the gland 8; the safety valve 12 is used for releasing pressure when the communication cavity 10 is in overpressure; an L-shaped positioning plate 13 is arranged at the bottom of the metamaterial structure layer 3; and an L-shaped positioning groove matched with the L-shaped positioning plate 13 is formed in the bottom of the metal shell 1. According to the structure, the concave circular groove 9 is provided with the plurality of micropores 11, the bottom of the metamaterial structure layer 3 is provided with the L-shaped positioning plate 13, the position and the angle of the metamaterial structure layer 3 are uniquely determined when the L-shaped positioning plate 13 is matched with the L-shaped positioning groove, the position is preset, the best effect is ensured, the position of the metamaterial structure layer 3 is prevented from being adjusted every time, all the hollow cavities 6 are correspondingly provided with the micropores 11 communicated with the communicating cavity 10, and the heated space 4 is correspondingly provided with the micropores 11 communicated with the communicating cavity 10; when the air pressure of the middle cavity 6 or the heated space 4 is too high, the air enters the communicating cavity 10 through the micropores 11 and then is decompressed out from the safety valve 12, and the effect of safety protection is achieved. The micro-holes 11 are small, resembling a cut-off waveguide, from which the microwaves cannot escape.
Further, the water tank 14 and the heat-insulating ceramic seat 15 are also included; the bottom of the metal shell 1 is provided with a heat insulation ceramic seat 15; a heat exchange coil 16 attached to the bottom of the metal shell 1 is arranged in the heat insulation ceramic seat 15; an inlet valve 17 is arranged at the inlet of the heat exchange coil 16; the inlet valve 17 is connected with a water outlet pipe of the water tank 14; an outlet valve 18 is arranged on the outlet of the heat exchange coil 16; the outlet valve 18 is connected with a water pump 19; the water pump 19 is connected to the inlet pipe of the water tank 14. As can be seen from the above structure, the insulating ceramic mount 15 insulates and isolates the metal case 1 from the stage, and prevents the influence on other devices. A temperature sensor is arranged in the communicating cavity 10, when the temperature sensor detects that the temperature of the heated space 4 is too high, the inlet valve 17, the outlet valve 18 and the water pump 19 are opened, water in the water tank 14 flows to the heat exchange coil 16 to exchange heat with the heated space 4, and meanwhile, the microwave source reduces the microwave input power or stops inputting microwaves, so that the heated space 4 is cooled. The metal shell 1 is prevented from exceeding the upper limit of the used high temperature, and the effect of safety protection is achieved.
A method for improving microwave heating efficiency, adopt the above-mentioned apparatus for improving microwave heating efficiency, including preparing the step, heating step, relieving pressure step and cooling step;
the preparation steps are specifically that the gland 8 is opened, and the metamaterial structural layer 3 is placed into the metal shell 1 from the opening 7 at the top of the metal shell 1; positioning the metamaterial structure layer 3 through an L positioning plate 13 and an L positioning groove at the bottom of the metal shell 1; placing the heated object in the heated space 4; covering a gland 8, enabling a concave circular groove 9 at the bottom of the gland 8 to be matched with the top of the metamaterial structure layer 3, enabling all hollow cavities 6 to be correspondingly provided with a micropore 11 communicated with a communicating cavity 10 at the moment, and enabling the heated space 4 to be correspondingly provided with micropores 11 communicated with the communicating cavity 10;
the heating step specifically comprises the steps of selecting a microwave source, inputting microwaves to the feed port 2 by the microwave source, collecting the microwaves in the heated space 4 when the microwaves pass through the metamaterial structural layer 3, and heating the heated object by absorbing the microwaves;
the pressure relief step is specifically that when the air pressure of the middle cavity 6 or the heated space 4 is too high, the air enters the communicating cavity 10 through the micropores 11 and then is relieved from the safety valve 12;
the step of cooling is specifically that a temperature sensor is arranged in the communicating cavity 10, when the temperature sensor detects that the temperature of the heated space 4 is too high, the inlet valve 17, the outlet valve 18 and the water pump 19 are opened, water in the water tank 14 flows to the heat exchange coil 16 to exchange heat with the heated space 4, and meanwhile, the microwave source reduces the microwave input power or stops inputting microwaves, so that the heated space 4 is cooled.
The invention has the beneficial effects that:
the invention discloses a device and a method for improving microwave heating efficiency, belonging to the technical field of microwave application and comprising a metal shell; a feed port is formed in the metal shell; the feed port is used for inputting microwaves into the metal shell; a metamaterial structure layer is arranged inside the metal shell; a heated space is arranged in the center of the metamaterial structure layer; the relative dielectric constant of the metamaterial structure layer gradually increases from outside to inside, so that the microwaves passing through the metamaterial structure layer are collected in the heated space. The device and the method for improving the microwave heating efficiency can concentrate the microwave energy input into the metal shell into the heated space, and have the advantages of high heating speed and high energy utilization rate. The repeated design and modification of the microwave heating cavity are avoided, the energy utilization rate is improved, the work of the cavity design is reduced, and the problem of complex cavity design is solved. The microwave heating device is different from the existing microwave heating mode in that energy is dispersed in the whole heating cavity, the microwave heating device can improve the electric field distribution of the area to be heated, and the heated object can efficiently absorb and utilize microwave energy.
Drawings
FIG. 1 is a schematic sectional front view of a metal casing of the apparatus for improving microwave heating efficiency according to the present invention;
FIG. 2 is a schematic sectional top view of the metal casing of the apparatus for improving microwave heating efficiency according to the present invention;
FIG. 3 is a schematic diagram of a heat exchange structure of the apparatus for improving microwave heating efficiency according to the present invention;
FIG. 4 is a schematic representation of the inventive function ε (d) and a step function in a coordinate system;
in the drawings: 1-metal shell, 2-feed port, 3-metamaterial structure layer, 4-heated space, 5-ring column, 6-hollow cavity, 7-opening, 8-gland, 9-concave circular groove, 10-communicating cavity, 11-micropore, 12-safety valve, 13-L positioning plate, 14-water tank, 15-heat insulation ceramic seat, 16-heat exchange coil, 17-inlet valve, 18-outlet valve and 19-water pump.
Detailed Description
The present invention will be described in further detail below with reference to the drawings and the embodiments, but the present invention is not limited to the following examples.
The first embodiment is as follows:
see figures 1-4. A device for improving microwave heating efficiency comprises a metal shell 1; a feed port 2 is arranged on the metal shell 1; the feed port 2 is used for inputting microwaves into the metal shell 1; a metamaterial structure layer 3 is arranged inside the metal shell 1; a heated space 4 is arranged in the center of the metamaterial structure layer 3; the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, so that the microwaves passing through the metamaterial structure layer 3 are collected in the heated space 4. According to the structure, the microwave source inputs microwaves to the feed port 2, the microwaves are collected in the heated space 4 after entering the metal shell 1 and passing through the metamaterial structural layer 3, the collected microwaves are continuously absorbed by the heated object in the heated space 4, the microwaves can only enter the special structure of the metamaterial structural layer 3, the reflection in the metal shell 1 is reduced, the utilization rate of the microwave energy is improved, the energy density is high, and the heated object can efficiently absorb and utilize the microwave energy. Due to the characteristics of the metamaterial structure layer 3, the collection of microwaves in the heated space 4 is not affected by the position of the feed port 2, the shape of the metal shell 1 and the parameter change of the heated object, and the heated object can still absorb and utilize the microwave energy efficiently. The metamaterial structure layer 3 can realize that the microwave only enters but not exits because the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, the increasing can be continuous, smooth and gradually increasing or stepped gradually increasing, namely, the relative dielectric constant of the outermost material part of the metamaterial structure layer 3 is minimum, the relative dielectric constant of the innermost material part of the metamaterial structure layer 3 is maximum, the principle of the metamaterial structure layer is similar to that the microwave passes through the metamaterial structure layer 3 and is continuously refracted to the heated space 4, and the microwave only enters the heated space 4 and cannot escape when passing through the metamaterial structure layer 3.
Example two:
see figures 1-4. A device for improving microwave heating efficiency comprises a metal shell 1; a feed port 2 is arranged on the metal shell 1; the feed port 2 is used for inputting microwaves into the metal shell 1; a metamaterial structure layer 3 is arranged inside the metal shell 1; a heated space 4 is arranged in the center of the metamaterial structure layer 3; the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, so that the microwaves passing through the metamaterial structure layer 3 are collected in the heated space 4. According to the structure, the microwave source inputs microwaves to the feed port 2, the microwaves are collected in the heated space 4 after entering the metal shell 1 and passing through the metamaterial structural layer 3, the collected microwaves are continuously absorbed by the heated object in the heated space 4, the microwaves can only enter the special structure of the metamaterial structural layer 3, the reflection in the metal shell 1 is reduced, the utilization rate of the microwave energy is improved, the energy density is high, and the heated object can efficiently absorb and utilize the microwave energy. Due to the characteristics of the metamaterial structure layer 3, the collection of microwaves in the heated space 4 is not affected by the position of the feed port 2, the shape of the metal shell 1 and the parameter change of the heated object, and the heated object can still absorb and utilize the microwave energy efficiently. The metamaterial structure layer 3 can realize that the microwave only enters but not exits because the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, the increasing can be continuous, smooth and gradually increasing or stepped gradually increasing, namely, the relative dielectric constant of the outermost material part of the metamaterial structure layer 3 is minimum, the relative dielectric constant of the innermost material part of the metamaterial structure layer 3 is maximum, the principle of the metamaterial structure layer is similar to that the microwave passes through the metamaterial structure layer 3 and is continuously refracted to the heated space 4, and the microwave only enters the heated space 4 and cannot escape when passing through the metamaterial structure layer 3.
The metamaterial structure layer 3 comprises a plurality of ring columns 5 which are sequentially nested from inside to outside; the heated space 4 is a cylindrical space with a radius r; the radius of the metamaterial structure layer 3 is R; the relative dielectric constant of the space outside the metamaterial structure layer 3 is epsilon0(ii) a The relative dielectric constants of all position points of the metamaterial structure layer 3 form a step function, the distance between each position point and the center of the heated space 4 is d, wherein R is more than d and more than R; each step of the step function and the additionally constructed function epsilon (d) ∈ epsilon0(R/d)2And (4) intersecting. As can be seen from the above-described structure, in the conventional theory, the metamaterial structure layer 3 collects the microwaves into the heated space 4, and the relative dielectric constant of the material is approximated by the function ∈ (d) ∈ (e) —0(R/d)2Namely, the relative dielectric constants of each metamaterial structure layer 3 and the heated space 4 at different axial positions are different. Since air is arranged between the metamaterial structure layer 3 and the metal shell 1, epsilon0Is the relative dielectric constant of air; in practice, however, such a structure is difficult to realize, and the metamaterial structure layer 3 is formed by using a plurality of ring pillars 5 which are nested from inside to outside, so that the relative dielectric constant of the ring pillars 5 at corresponding positions is only required to be approximate to a function epsilon (d) ═ epsilon0(R/d)2The metamaterial structure layer 3 with gradually increased relative dielectric constant of the materials from outside to inside can be formed. For example, if the inner diameter of a certain ring column 5 is d1 and the outer diameter is d2, the relative dielectric constant of the ring column 5 is adopted for the position points which are separated from the axial center of the heated space 4 by the interval of d 1-d 2, so that the relative dielectric constant and the position points of all the ring columns 5 are presented as a step function on the coordinate system. Only each step of the step function and the additionally constructed function epsilon (d) need to be equal to epsilon0(R/d)2Intersecting, i.e. reaching the sum function e (d) e0(R/d)2The purpose of the approach is to collect the microwave. For example, the annular column 5 has an inner diameter d1, an outer diameter d2, a relative dielectric constant e 1, and a horizontal line segment whose abscissa is d1 to d2 and whose ordinate is e 1, and the sum of the horizontal line segment and the function e (d) is e 10(R/d)2And (4) intersecting. The plurality of ring columns 5 nested from inside to outside in sequence comprise a virtual nesting, for example, a material whole with gradually changed relative dielectric constant can be regarded as the ring columns 5 nested from inside to outside in sequence in a virtual manner, and is actually a whole material, and the virtual nesting is also included in the nesting concept protected by the invention, so that the processing is convenient, and the cost is reduced.
Example three:
see figures 1-4. A device for improving microwave heating efficiency comprises a metal shell 1; a feed port 2 is arranged on the metal shell 1; the feed port 2 is used for inputting microwaves into the metal shell 1; a metamaterial structure layer 3 is arranged inside the metal shell 1; a heated space 4 is arranged in the center of the metamaterial structure layer 3; the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, so that the microwaves passing through the metamaterial structure layer 3 are collected in the heated space 4. According to the structure, the microwave source inputs microwaves to the feed port 2, the microwaves are collected in the heated space 4 after entering the metal shell 1 and passing through the metamaterial structural layer 3, the collected microwaves are continuously absorbed by the heated object in the heated space 4, the microwaves can only enter the special structure of the metamaterial structural layer 3, the reflection in the metal shell 1 is reduced, the utilization rate of the microwave energy is improved, the energy density is high, and the heated object can efficiently absorb and utilize the microwave energy. Due to the characteristics of the metamaterial structure layer 3, the collection of microwaves in the heated space 4 is not affected by the position of the feed port 2, the shape of the metal shell 1 and the parameter change of the heated object, and the heated object can still absorb and utilize the microwave energy efficiently. The metamaterial structure layer 3 can realize that the microwave only enters but not exits because the relative dielectric constant of the metamaterial structure layer 3 gradually increases from outside to inside, the increasing can be continuous, smooth and gradually increasing or stepped gradually increasing, namely, the relative dielectric constant of the outermost material part of the metamaterial structure layer 3 is minimum, the relative dielectric constant of the innermost material part of the metamaterial structure layer 3 is maximum, the principle of the metamaterial structure layer is similar to that the microwave passes through the metamaterial structure layer 3 and is continuously refracted to the heated space 4, and the microwave only enters the heated space 4 and cannot escape when passing through the metamaterial structure layer 3.
The metamaterial structure layer 3 comprises a plurality of ring columns 5 which are sequentially nested from inside to outside; the heated space 4 is a cylindrical space with a radius r; the radius of the metamaterial structure layer 3 is R; the relative dielectric constant of the space outside the metamaterial structure layer 3 is epsilon0(ii) a The relative dielectric constants of all position points of the metamaterial structure layer 3 form a step function, the distance between each position point and the center of the heated space 4 is d, wherein R is more than d and more than R; each step of the step function and the additionally constructed function epsilon (d) ∈ epsilon0(R/d)2And (4) intersecting. As can be seen from the above-described structure, in the conventional theory, the metamaterial structure layer 3 collects the microwaves into the heated space 4, and the relative dielectric constant of the material is approximated by the function ∈ (d) ∈ (e) —0(R/d)2Namely, the relative dielectric constants of each metamaterial structure layer 3 and the heated space 4 at different axial positions are different. Since air is arranged between the metamaterial structure layer 3 and the metal shell 1, epsilon0Is the relative dielectric constant of air; in practice, however, such a structure is difficult to realize, and the metamaterial structure layer 3 is formed by using a plurality of ring pillars 5 which are nested from inside to outside, so that the relative dielectric constant of the ring pillars 5 at corresponding positions is only required to be approximate to a function epsilon (d) ═ epsilon0(R/d)2The metamaterial structure layer 3 with gradually increased relative dielectric constant of the materials from outside to inside can be formed. Example (b)If the inner diameter of one ring column 5 is d1 and the outer diameter is d2, the relative dielectric constant of the ring column 5 is adopted for the position points which are separated from the axial center of the heated space 4 by the interval of d 1-d 2, so that the relative dielectric constant and the position points of all the ring columns 5 are presented as a step function on the coordinate system. Only each step of the step function and the additionally constructed function epsilon (d) need to be equal to epsilon0(R/d)2Intersecting, i.e. reaching the sum function e (d) e0(R/d)2The purpose of the approach is to collect the microwave. For example, the annular column 5 has an inner diameter d1, an outer diameter d2, a relative dielectric constant e 1, and a horizontal line segment whose abscissa is d1 to d2 and whose ordinate is e 1, and the sum of the horizontal line segment and the function e (d) is e 10(R/d)2And (4) intersecting. The plurality of ring columns 5 nested from inside to outside in sequence comprise a virtual nesting, for example, a material whole with gradually changed relative dielectric constant can be regarded as the ring columns 5 nested from inside to outside in sequence in a virtual manner, and is actually a whole material, and the virtual nesting is also included in the nesting concept protected by the invention, so that the processing is convenient, and the cost is reduced.
A plurality of hollow cavities 6 are arranged on the ring column 5; two ends of the hollow cavity 6 respectively extend to the top bottom surface of the corresponding ring column 5. According to the structure, the ring column 5 can adopt polyvinylidene fluoride as a base material, and the relative dielectric constant of the ring column 5 can be changed by arranging the hollow cavity 6 on the ring column 5. Calculation and experimental verification can be carried out through the existing theory.
The cross section of the hollow cavity 6 of the outer ring column 5 is larger than the cross section of the hollow cavity 6 of the inner ring column 5. As can be seen from the above structure, the larger the cross section of the hollow cavity 6, the smaller the relative dielectric constant of the ring pillar 5, and the smaller the cross section of the hollow cavity 6, the larger the relative dielectric constant of the ring pillar 5. The section of the hollow cavity 6 of the inner ring column 5 from the outside is smaller and smaller, and the relative dielectric constant of the metamaterial structure layer 3 gradually increases from the outside to the inside.
The hollow cavities 6 on the ring column 5 are uniformly spaced; the number of hollow cavities 6 in each ring post 5 is equal. As can be seen from the above structure, the microwaves enter the metamaterial structure layer 3 from a plurality of angles except the axial direction of the metamaterial structure layer 3, and can be collected in the heated space 4.
The cross section of the hollow cavity 6 is circular, oval or polygonal. From the above structure, the hollow cavity 6 can adopt various cross-sectional shapes to change the relative dielectric constant of the ring pillar 5, and conventionally can adopt a cross-section of a circle.
The top of the metal shell 1 is provided with an opening 7; a gland 8 is arranged on the opening 7; the bottom of the gland 8 is provided with a concave circular groove 9; the concave circular groove 9 is matched at the top of the metamaterial structure layer 3; the metamaterial structural layer 3 is sandwiched between the gland 8 and the bottom of the metal shell 1. According to the structure, the concave circular groove 9 is matched with the top of the metamaterial structure layer 3, so that the metamaterial structure layer 3 is clamped between the gland 8 and the bottom of the metal shell 1, no gap exists at the bottom of the top of the metamaterial structure layer 3, and the microwave is prevented from escaping from the heated space 4.
A communicating cavity 10 is arranged in the gland 8; the concave circular groove 9 is provided with a plurality of micropores 11; the micropores 11 enable all the hollow cavities 6 and the heated spaces 4 to be communicated with the communication cavity 10 respectively; a safety valve 12 is arranged on the gland 8; the safety valve 12 is used for releasing pressure when the communication cavity 10 is in overpressure; an L-shaped positioning plate 13 is arranged at the bottom of the metamaterial structure layer 3; and an L-shaped positioning groove matched with the L-shaped positioning plate 13 is formed in the bottom of the metal shell 1. According to the structure, the concave circular groove 9 is provided with the plurality of micropores 11, the bottom of the metamaterial structure layer 3 is provided with the L-shaped positioning plate 13, the position and the angle of the metamaterial structure layer 3 are uniquely determined when the L-shaped positioning plate 13 is matched with the L-shaped positioning groove, the position is preset, the best effect is ensured, the position of the metamaterial structure layer 3 is prevented from being adjusted every time, all the hollow cavities 6 are correspondingly provided with the micropores 11 communicated with the communicating cavity 10, and the heated space 4 is correspondingly provided with the micropores 11 communicated with the communicating cavity 10; when the air pressure of the middle cavity 6 or the heated space 4 is too high, the air enters the communicating cavity 10 through the micropores 11 and then is decompressed out from the safety valve 12, and the effect of safety protection is achieved. The micro-holes 11 are small, resembling a cut-off waveguide, from which the microwaves cannot escape.
Also comprises a water tank 14 and a heat-insulating ceramic seat 15; the bottom of the metal shell 1 is provided with a heat insulation ceramic seat 15; a heat exchange coil 16 attached to the bottom of the metal shell 1 is arranged in the heat insulation ceramic seat 15; an inlet valve 17 is arranged at the inlet of the heat exchange coil 16; the inlet valve 17 is connected with a water outlet pipe of the water tank 14; an outlet valve 18 is arranged on the outlet of the heat exchange coil 16; the outlet valve 18 is connected with a water pump 19; the water pump 19 is connected to the inlet pipe of the water tank 14. As can be seen from the above structure, the insulating ceramic mount 15 insulates and isolates the metal case 1 from the stage, and prevents the influence on other devices. A temperature sensor is arranged in the communicating cavity 10, when the temperature sensor detects that the temperature of the heated space 4 is too high, the inlet valve 17, the outlet valve 18 and the water pump 19 are opened, water in the water tank 14 flows to the heat exchange coil 16 to exchange heat with the heated space 4, and meanwhile, the microwave source reduces the microwave input power or stops inputting microwaves, so that the heated space 4 is cooled. The metal shell 1 is prevented from exceeding the upper limit of the used high temperature, and the effect of safety protection is achieved.
Example four:
see figures 1-4. A method for improving microwave heating efficiency, adopt the above-mentioned apparatus for improving microwave heating efficiency, including preparing the step, heating step, relieving pressure step and cooling step;
the preparation steps are specifically that the gland 8 is opened, and the metamaterial structural layer 3 is placed into the metal shell 1 from the opening 7 at the top of the metal shell 1; positioning the metamaterial structure layer 3 through an L positioning plate 13 and an L positioning groove at the bottom of the metal shell 1; placing the heated object in the heated space 4; covering a gland 8, enabling a concave circular groove 9 at the bottom of the gland 8 to be matched with the top of the metamaterial structure layer 3, enabling all hollow cavities 6 to be correspondingly provided with a micropore 11 communicated with a communicating cavity 10 at the moment, and enabling the heated space 4 to be correspondingly provided with micropores 11 communicated with the communicating cavity 10;
the heating step specifically comprises the steps of selecting a microwave source, inputting microwaves to the feed port 2 by the microwave source, collecting the microwaves in the heated space 4 when the microwaves pass through the metamaterial structural layer 3, and heating the heated object by absorbing the microwaves;
the pressure relief step is specifically that when the air pressure of the middle cavity 6 or the heated space 4 is too high, the air enters the communicating cavity 10 through the micropores 11 and then is relieved from the safety valve 12;
the step of cooling is specifically that a temperature sensor is arranged in the communicating cavity 10, when the temperature sensor detects that the temperature of the heated space 4 is too high, the inlet valve 17, the outlet valve 18 and the water pump 19 are opened, water in the water tank 14 flows to the heat exchange coil 16 to exchange heat with the heated space 4, and meanwhile, the microwave source reduces the microwave input power or stops inputting microwaves, so that the heated space 4 is cooled.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (9)
1. The utility model provides an improve device of microwave heating efficiency which characterized in that: comprises a metal shell (1); a feed opening (2) is formed in the metal shell (1); the feed port (2) is used for inputting microwaves into the metal shell (1); a metamaterial structure layer (3) is arranged in the metal shell (1); a heated space (4) is arranged in the center of the metamaterial structure layer (3); the relative dielectric constant of the metamaterial structure layer (3) is gradually increased from outside to inside, so that the microwaves passing through the metamaterial structure layer (3) are collected in the heated space (4); the metamaterial structure layer (3) comprises a plurality of ring columns (5) which are sequentially nested from inside to outside; the heated space (4) is a cylindrical space with the radius r; the radius of the metamaterial structure layer (3) is R; the relative dielectric constant of the external space of the metamaterial structure layer (3) is epsilon0(ii) a The relative dielectric constant of each position point of the metamaterial structure layer (3) forms a step function, the distance between the position point and the center of the heated space (4) is d, wherein R is more than d and more than R; each step of the step function and the additionally constructed function epsilon (d) ∈ epsilon0(R/d)2And (4) intersecting.
2. An apparatus for increasing microwave heating efficiency as set forth in claim 1, wherein: a plurality of hollow cavities (6) are arranged on the ring column (5); two ends of the hollow cavity (6) respectively extend to the top and bottom surfaces of the corresponding ring columns (5).
3. An apparatus for increasing microwave heating efficiency as set forth in claim 2, wherein: the cross section of the hollow cavity (6) of the outer ring column (5) is larger than the cross section of the hollow cavity (6) of the inner ring column (5).
4. An apparatus for increasing microwave heating efficiency as set forth in claim 3, wherein: the hollow cavities (6) on the ring column (5) are uniformly spaced; the number of hollow cavities (6) on each ring column (5) is equal.
5. An apparatus for increasing microwave heating efficiency as set forth in claim 4, wherein: the cross section of the hollow cavity (6) is circular, oval or polygonal.
6. An apparatus for increasing microwave heating efficiency as set forth in claim 5, wherein: an opening (7) is formed in the top of the metal shell (1); a gland (8) is arranged on the opening (7); a concave circular groove (9) is formed in the bottom of the gland (8); the concave circular groove (9) is matched with the top of the metamaterial structure layer (3); the metamaterial structure layer (3) is clamped between the gland (8) and the bottom of the metal shell (1).
7. An apparatus for increasing microwave heating efficiency as set forth in claim 6, wherein: a communicating cavity (10) is arranged in the gland (8); a plurality of micropores (11) are arranged on the concave circular groove (9); the micropores (11) enable all the hollow cavities (6) and the heated space (4) to be respectively communicated with the communicating cavity (10); a safety valve (12) is arranged on the gland (8); the safety valve (12) is used for releasing pressure when the communication cavity (10) is overpressure; an L-shaped positioning plate (13) is arranged at the bottom of the metamaterial structure layer (3); and an L-shaped positioning groove matched with the L-shaped positioning plate (13) is formed in the bottom of the metal shell (1).
8. An apparatus for increasing microwave heating efficiency as set forth in claim 7, wherein: the water tank (14) and the heat-insulating ceramic seat (15) are also included; the bottom of the metal shell (1) is provided with a heat insulation ceramic seat (15); a heat exchange coil (16) attached to the bottom of the metal shell (1) is arranged in the heat insulation ceramic seat (15); an inlet valve (17) is arranged at the inlet of the heat exchange coil (16); the inlet valve (17) is connected with a water outlet pipe of the water tank (14); an outlet valve (18) is arranged on the outlet of the heat exchange coil (16); the outlet valve (18) is connected with a water pump (19); the water pump (19) is connected with a water inlet pipe of the water tank (14).
9. A method for improving microwave heating efficiency is characterized in that: the device for improving microwave heating efficiency according to claim 8, comprising a preparation step, a heating step, a pressure relief step and a temperature reduction step;
the preparation steps comprise the steps of opening a gland (8), and putting the metamaterial structure layer (3) into the metal shell (1) from an opening (7) in the top of the metal shell (1); positioning the metamaterial structure layer (3) through an L positioning plate (13) and an L positioning groove at the bottom of the metal shell (1); placing the heated object in the heated space (4); covering a gland (8), enabling a concave circular groove (9) at the bottom of the gland (8) to be matched with the top of the metamaterial structure layer (3), enabling all hollow cavities (6) to be correspondingly provided with a micropore (11) communicated with a communication cavity (10), and enabling the heated space (4) to be correspondingly provided with the micropore (11) to be communicated with the communication cavity (10);
the heating step specifically comprises the steps that a microwave source is selected, microwaves are input into the feed port (2) by the microwave source, the microwaves are collected in the heated space (4) when passing through the metamaterial structural layer (3), and the heated object absorbs the microwaves to be heated;
the pressure relief step is specifically that when the air pressure of the middle cavity (6) or the heated space (4) is too high, the air enters the communicating cavity (10) through the micropores (11) and then is relieved from the safety valve (12);
the cooling step is specifically that a temperature sensor is arranged in the communicating cavity (10), when the temperature sensor detects that the temperature of the heated space (4) is too high, an inlet valve (17), an outlet valve (18) and a water pump (19) are opened, water in the water tank (14) flows to the heat exchange coil (16) to exchange heat with the heated space (4), and meanwhile, the microwave source reduces microwave input power or stops inputting microwaves, so that the heated space (4) is cooled.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011422828.8A CN112512154B (en) | 2020-12-08 | 2020-12-08 | Device and method for improving microwave heating efficiency |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011422828.8A CN112512154B (en) | 2020-12-08 | 2020-12-08 | Device and method for improving microwave heating efficiency |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112512154A CN112512154A (en) | 2021-03-16 |
| CN112512154B true CN112512154B (en) | 2021-09-14 |
Family
ID=74971285
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011422828.8A Active CN112512154B (en) | 2020-12-08 | 2020-12-08 | Device and method for improving microwave heating efficiency |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112512154B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114245505B (en) * | 2021-11-30 | 2022-12-06 | 四川大学 | Microwave film heating device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102784436B (en) * | 2011-05-16 | 2015-04-29 | 深圳光启高等理工研究院 | Microwave hyperthermia therapy radiator and microwave hyperthermia therapy device |
| CN102476950B (en) * | 2011-06-01 | 2013-06-12 | 深圳光启高等理工研究院 | Method for preparing medium substrate with heterogeneous dielectric constant and meta material |
-
2020
- 2020-12-08 CN CN202011422828.8A patent/CN112512154B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112512154A (en) | 2021-03-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100523686C (en) | Efficient energy-saving drying process and apparatus | |
| CN112512154B (en) | Device and method for improving microwave heating efficiency | |
| CN112569885B (en) | Microwave reaction device with reflection protection | |
| CN204438769U (en) | A kind of magnetic suspension induction melting water jacketed copper crucible | |
| CN102698683B (en) | Adjustable-frequency resonance microwave reaction chamber with open top | |
| CN106409357A (en) | Reactor with passive reactor core waste heat emission function | |
| CN217591139U (en) | Waveguide slot array heater | |
| CN208589548U (en) | A kind of circular waveguide leaky wave slot antenna based on TM01 mould | |
| CN104538152A (en) | Oil type transformer and application thereof | |
| CN108895676A (en) | A kind of built-in porous media trough type solar heat-collector of augmentation of heat transfer | |
| CN108391332A (en) | A kind of new energy high-frequency induction machine | |
| CN202519305U (en) | Inductor applies to heat treatment of working roll | |
| CN204178825U (en) | A kind of vacuum microwave drying recycling processing unit of high temperature resistant communication cable insulating technique | |
| CN104332257A (en) | Vacuum microwave drying method and drying recycling treater of high temperature-resistant communication cable insulation process | |
| CN202816398U (en) | Reactor fuel assembly shroud with tents and chamfers and reactor fuel assembly | |
| CN106044775A (en) | Base plate assembly for polycrystalline silicon reduction furnace and polycrystalline silicon reduction furnace with same | |
| CN109722057A (en) | Graphene composite material, preparation method and its preparation facilities of high heat conductance | |
| CN112584599B (en) | Efficient microwave plasma torch | |
| CN202655019U (en) | Frequency-adjustable resonant microwave reaction cavity with open top | |
| CN212636345U (en) | Rotational molding mechanism for continuously heating plastic barrel in production and processing | |
| CN207427495U (en) | Graphite heater group | |
| CN106448757A (en) | Reactor with passive reactor core residual heat removal function | |
| CN205856516U (en) | A kind of annealing device of converter taphole | |
| CN212092210U (en) | Spiral extrusion continuous microwave process strengthening reactor | |
| CN203734863U (en) | Inductive heater |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |