JPWO2012137447A1 - Microwave heating device - Google Patents

Abstract

In the microwave heating apparatus according to the present invention, the end (107) of the microwave transmission direction (MT) in the waveguide (106) is generated so as to generate a predetermined standing wave (SW) in the waveguide (106). ) Is closed, and the nodes and antinodes of the standing wave (SW) generated in the waveguide (106) are arranged substantially symmetrically with respect to the center of the heating chamber (103). The object to be heated (102) can be heated by microwaves substantially uniformly without using.

Description

  The present invention relates to a microwave heating apparatus such as a microwave oven, and more particularly to a microwave heating apparatus characterized by a configuration for radiating microwaves into a heating chamber.

  Conventionally, there is a microwave oven as a typical apparatus for a microwave heating apparatus that heats an object to be heated with this type of microwave. In the microwave oven, the microwave generated in the microwave supply means is radiated into the metal heating chamber, and the object to be heated in the heating chamber is heated by the radiated microwave.

  A magnetron is used as a microwave supply means in a conventional microwave oven. Microwaves generated by the magnetron are radiated from the microwave radiating portion into the heating chamber through the waveguide. If the electromagnetic field distribution of the microwaves in the heating chamber is not uniform, there is a problem that the object to be heated cannot be uniformly heated by microwaves.

  As a means for uniformly heating the object to be heated in the heating chamber, a structure for rotating the table on which the object to be heated is rotated to rotate the object to be heated in the heating chamber, and fixing the object to be heated by the microwave There is a structure that rotates the antenna that radiates the light, or a structure that changes the phase of the microwave propagated from the microwave supply means using a phase shifter, and a microwave heating device having such a structure is generally used. It has been.

  For example, in a conventional microwave heating apparatus, a rotating antenna, an antenna shaft, and the like are arranged inside a waveguide, and a microwave distribution in a heating chamber is driven by driving a magnetron while rotating the rotating antenna by an antenna motor. Some have a structure that reduces non-uniformity.

  Japanese Laid-Open Patent Publication No. 62-64093 (Patent Document 1) describes a microwave heating apparatus having another configuration. In this Patent Document 1, a rotatable antenna is provided on the upper part of a magnetron, and the antenna is rotated by the wind force of the blower fan by applying the wind from the blower fan to the blades of the rotary antenna. Microwave heating devices that change the wave distribution have been proposed.

  On the other hand, a microwave heating apparatus that reduces non-uniform heating of an object to be heated by microwave heating, reduces costs, and saves space in a microwave power feeding unit is disclosed in US Pat. No. 4,301,347 (Patent Document 2). )It is described in. Patent Document 2 proposes a microwave heating apparatus having a single microwave radiating section that radiates circularly polarized waves into the heating chamber.

JP-A-62-64093 U.S. Pat. No. 4,301,347

  A microwave heating apparatus such as a microwave oven having the above-described conventional configuration is required to have a simple structure as much as possible and to efficiently heat an object to be heated with high uniformity. However, the conventional configurations proposed so far are not satisfactory and have various problems in terms of efficiency and uniformity in terms of structure.

  Further, in microwave heating devices, particularly microwave ovens, technological development for higher output has progressed, and products with a rated high-frequency output of 1000 W have been commercialized in Japan. Microwave ovens are notable for heating food by heat conduction, but the convenience of being able to heat food directly using dielectric heating is a major feature of this product. However, in a microwave oven, increasing the output in a state where non-uniform heating is unsolved will make the problem of non-uniform heating more obvious.

  The following two points are given as structural problems of the conventional microwave heating apparatus. The first point requires a mechanism for rotating the table or antenna to reduce non-uniform heating. Therefore, a rotation space and a space for installing a drive source such as a motor for rotating the table or antenna are secured. It is necessary to reduce the size of the microwave oven. The second point is that in order to rotate the table or antenna stably, it is necessary to provide the antenna above or below the heating chamber, which is limited in structure.

  In addition, various mechanisms such as a table or antenna rotation mechanism and a phase shifter are installed in the microwave irradiation space that leads to the heating chamber of the microwave heating apparatus. It has a problem of reducing the performance. Accordingly, there is a need for a microwave heating apparatus that does not require these mechanisms.

  Further, in the microwave heating apparatus described in Patent Document 2 which aims to reduce uneven heating of an object to be heated by microwave heating, and to reduce the cost and save the space of the microwave power feeding section, the following is also applied. Have a serious problem. The microwave heating device having a single microwave radiating unit that radiates circularly polarized waves into the inside of the heating chamber disclosed in Patent Document 2 has an advantage that it does not have a rotating mechanism. There is a problem that sufficient uniform heating cannot be realized.

  The present invention solves the above-described problems in the conventional technology, and an object thereof is to provide a microwave heating apparatus capable of uniformly heating an object to be heated without using a rotating mechanism. .

The microwave heating apparatus according to the present invention is
A heating chamber in which an object to be heated is arranged;
A microwave supply unit for generating microwaves to be supplied to the heating chamber;
A waveguide for transmitting the microwave generated by the microwave supply unit to the heating chamber;
A plurality of microwave radiation portions for radiating microwaves transmitted through the waveguide to the heating chamber,
The end of the microwave transmission direction in the waveguide is closed so as to generate a predetermined standing wave in the waveguide,
A distribution of standing waves generated in the waveguide is arranged substantially symmetrically with respect to the center of the heating chamber.

  In the microwave heating apparatus according to the present invention configured as described above, the microwave from the microwave radiating unit, which is the basis of the energy radiated to the object to be heated arranged in the heating chamber, is generated in the waveguide. As the standing waves generated in the heating chamber are evenly arranged with respect to the heating chamber, the heating distribution of the object to be heated can be made uniform.

  In the microwave heating apparatus of the present invention, the microwave from the microwave radiating unit that radiates the object to be heated arranged in the heating chamber is evenly arranged in the heating chamber as a standing wave generated in the waveguide. Therefore, the object to be heated can be uniformly microwave-heated.

Sectional drawing which shows schematic structure of the microwave heating apparatus of Embodiment 1 which concerns on this invention The perspective view which shows the microwave heating apparatus of Embodiment 1 which concerns on this invention. (A) The perspective view which shows the outline external appearance structure of the waveguide in the microwave heating apparatus of Embodiment 1 which concerns on this invention, (b) Side surface sectional drawing of the waveguide in the microwave heating apparatus of Embodiment 1, And (c) a plan view showing an arrangement state of the waveguide with respect to the heating chamber in the microwave heating apparatus of the first embodiment. The top view which shows the arrangement | positioning state of the waveguide with respect to the heating chamber in the microwave heating apparatus of Embodiment 2 which concerns on this invention The top view which shows the arrangement | positioning state of the waveguide with respect to the heating chamber in the microwave heating apparatus of Embodiment 3 which concerns on this invention

The microwave heating apparatus according to the first aspect of the present invention is
A heating chamber in which an object to be heated is arranged;
A microwave supply unit for generating microwaves to be supplied to the heating chamber;
A waveguide for transmitting the microwave generated by the microwave supply unit to the heating chamber;
A plurality of microwave radiation portions for radiating microwaves transmitted through the waveguide to the heating chamber,
In order to generate a standing wave having a predetermined wavelength in the waveguide, the end of the waveguide in the microwave transmission direction is closed, and the waveguide has a predetermined shape,
The distribution of standing waves generated in the waveguide is arranged substantially symmetrically with respect to the center of the heating region in the heating chamber.
In the microwave heating apparatus according to the first aspect of the present invention configured as described above, the microwave from the microwave radiating unit that radiates the object to be heated arranged in the heating chamber is generated in the waveguide. Since the standing waves are substantially evenly arranged with respect to the heating chamber, the object to be heated can be uniformly microwave-heated.

  In the microwave heating apparatus according to the second aspect of the present invention, in the first aspect, the plurality of microwave radiating portions are arranged substantially symmetrically with respect to the center of the heating region. In the microwave heating apparatus according to the second aspect of the present invention configured as described above, since the microwave radiating portion is arranged substantially symmetrically with respect to the center of the region, the microwave heating device is uniformly applied to the object to be heated. In addition, microwave heating can be performed with high efficiency.

  The microwave heating apparatus according to a third aspect of the present invention is the microwave heating apparatus according to the second aspect, wherein the distance between the centers of the plurality of microwave radiation portions is substantially the same as the interval between the standing waves generated in the waveguide. The microwave radiating portion is provided in the waveguide so as to be. In the microwave heating apparatus according to the third aspect of the present invention configured as described above, the microwave from the microwave radiating unit that radiates the object to be heated arranged in the heating chamber is generated in the waveguide. Since the microwave radiating portion is arranged corresponding to the distribution of the standing wave, the object to be heated can be heated with microwaves uniformly.

  In the microwave heating apparatus according to the fourth aspect of the present invention, in the third aspect, the position of the node of the standing wave generated in the waveguide corresponds to the center of the heating region of the heating chamber. It is configured. The microwave heating apparatus according to the fourth aspect of the present invention configured as described above can achieve uniform microwave radiation from the microwave radiation unit to the heating chamber.

  A microwave heating apparatus according to a fifth aspect of the present invention is the microwave heating apparatus according to the fourth aspect, wherein the microwave radiating portion is disposed corresponding to a position of a node of a standing wave generated in the waveguide. ing. The microwave heating device according to the fifth aspect of the present invention configured as described above can prevent excessive output from the microwave radiating unit, and can achieve more uniform microwave radiation to the heating chamber. . In particular, with such a configuration, microwaves can be efficiently radiated to an object to be heated disposed at the center of the heating chamber, and uniform heat treatment can be performed.

  The microwave heating apparatus according to a sixth aspect of the present invention is the microwave heating apparatus according to the fifth aspect, wherein a standing wave having an even number of antinodes is formed in a region in the waveguide facing the heating region in the heating chamber. ing. The microwave heating apparatus according to the sixth aspect of the present invention configured as described above can further uniform the microwave radiation with respect to the heating chamber in the microwave transmission direction of the waveguide.

  A microwave heating apparatus according to a seventh aspect of the present invention is the microwave heating apparatus according to the sixth aspect, wherein the microwave radiating portion is configured by an opening that radiates microwaves, and the opening is microwave transmission in the waveguide. They are arranged symmetrically with respect to the tube axis extending in the direction. The microwave heating device according to the seventh aspect of the present invention configured as described above can achieve uniform microwave radiation even in the heating region in the direction orthogonal to the microwave transmission direction in the waveguide. it can.

  The microwave heating apparatus according to an eighth aspect of the present invention is the microwave heating apparatus according to the sixth aspect, wherein the microwave radiating portion is configured by an opening that radiates microwaves, and the opening is microwave transmission in the waveguide. It is arranged asymmetrically with respect to the directional tube axis. The microwave heating apparatus according to the eighth aspect of the present invention configured as described above can make the microwave radiation uniform in the heating chamber.

  In the microwave heating apparatus according to the ninth aspect of the present invention, in any one of the first to eighth aspects, the amount of microwaves radiated from the microwave radiation unit is substantially the same. It is configured. The microwave heating device according to the ninth aspect of the present invention configured as described above can uniformize microwave radiation to the object to be heated from a plurality of microwave radiation portions.

  The microwave heating apparatus according to a tenth aspect of the present invention is the microwave heating apparatus according to any one of the first to eighth aspects, wherein the standing wave wavelength of the standing wave generated in the waveguide is the micro wave. The waveguide is configured to be substantially equal to the transmission wavelength of the microwave supplied from the wave supply unit and transmitted through the waveguide. The microwave heating apparatus according to the tenth aspect of the present invention configured as described above can stably generate a desired standing wave in the waveguide.

  According to an eleventh aspect of the microwave heating apparatus of the present invention, in any one of the first to eighth aspects, the microwave radiating unit is configured to radiate circularly polarized waves. In the microwave heating apparatus according to the eleventh aspect of the present invention configured as described above, a microwave having a spread is radiated from the microwave radiating section, and the microwave radiation is uniformly applied to the object to be heated in a wider range. Can be

  A microwave heating apparatus according to a twelfth aspect of the present invention is the microwave heating apparatus according to any one of the first to eighth aspects, wherein the microwave extends from the output end of the microwave supply unit to the end of the waveguide. The transmission distance is an integral multiple of a quarter of the transmission wavelength of the microwave supplied from the microwave supply unit and transmitted through the waveguide. The microwave heating device according to the twelfth aspect of the present invention configured as described above can generate a standing wave having the same wavelength as the transmission wavelength that is stably microwave-transmitted in the waveguide. Even when microwave radiation is performed from the microwave radiation portion to the heating chamber, the standing wave can be stably maintained in the waveguide.

  A microwave heating apparatus according to a thirteenth aspect of the present invention is the microwave heating apparatus according to any one of the first to eighth aspects, wherein the waveguide is a rectangular waveguide, and the microwave supply unit When the supplied wavelength is λ, and the length of the wall surface of the waveguide provided with the microwave radiating portion is perpendicular to the microwave transmission direction of the waveguide, a is generated in the waveguide. The standing wave wavelength of the standing wave is configured to be substantially equal to the transmission wavelength λg of the microwave transmitted through the waveguide represented by the following formula (1). The microwave heating apparatus according to the thirteenth aspect of the present invention configured as described above can reliably generate a standing wave having the same wavelength as the transmission wavelength that is stably microwave-transmitted in the waveguide. it can.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a microwave heating apparatus according to the invention will be described with reference to the accompanying drawings. In the microwave heating apparatus of the following embodiment, a microwave oven will be described. However, the microwave oven is an example, and the microwave heating apparatus of the present invention is not limited to the microwave oven, and uses dielectric heating. And a microwave heating device such as a garbage processing machine or a semiconductor manufacturing device.

  Further, the present invention is not limited to the specific configurations of the following embodiments, and configurations based on similar technical ideas are included in the present invention.

(Embodiment 1)
1 is a cross-sectional view showing a schematic configuration of a microwave heating apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the microwave heating apparatus according to the first embodiment includes a casing 101 that constitutes the appearance of the apparatus, a heating chamber 103 for microwave heating of an object to be heated 102, and heating inside the heating chamber 103. A placement unit 104 for placing the object 102, a microwave supply unit 105 for forming a microwave, and a waveguide 106 for transmitting the microwave from the microwave supply unit 105 to the heating chamber 103 are provided. It has been. In the microwave heating apparatus, the waveguide 106 is formed with a closed end portion 107 serving as a microwave transmission end and a microwave radiating portion 108 that radiates microwaves to the heating chamber 103. The microwave radiated from the microwave radiating unit 108 is configured to microwave-heat the object to be heated 102 on the placement unit 104 that is a heating region.

  In the microwave heating apparatus of the first embodiment, a glass plate is used as the mounting unit 104, a magnetron is used as the microwave supply unit 105, and the waveguide 106 is orthogonal to the microwave transmission direction. A rectangular waveguide having a square cross section is used. Further, the microwave radiating unit 108 is configured to include a radiation port 108 a that is an opening formed in the wall surface of the waveguide 106 that faces the heating chamber 103. By configuring as described above, the microwave heating apparatus according to the first embodiment can be realized with a simple configuration.

  FIG. 2 is a perspective view showing the microwave heating apparatus according to the first embodiment of the present invention. As shown in FIG. 2, the microwave heating apparatus of the first embodiment is provided with a door 201 for taking the article to be heated 102 into and out of the heating chamber 103. FIG. 2 shows a state in which the door 201 of the microwave heating apparatus is opened.

  FIG. 3A is a perspective view showing a schematic external configuration of the waveguide 106 in the microwave heating apparatus of the first embodiment. 3B is a side sectional view of the waveguide 106 in the microwave heating apparatus of the first embodiment, and FIG. 3C is a waveguide for the heating chamber 103 in the microwave heating apparatus of the first embodiment. 6 is a plan view showing an arrangement state of 106. FIG. The waveguide 106 and the heating chamber 103 shown in (c) of FIG. 3 are views of the waveguide 106 and the like viewed from above.

  In FIG. 3C, the heating chamber 103 is indicated by a one-dot chain line, and the microwave radiation unit 108 is indicated by a two-dot chain line. In FIG. 3C, the microwave radiating unit 108 indicated by a two-dot chain line is indicated by a rectangular region, but this rectangular region does not specify the shape of the microwave radiating unit 108, and is simply a microwave radiating unit. The region in which 108 openings are to be formed is shown. A specific opening shape of the microwave radiating unit 108 may be any shape as long as the microwave from the waveguide 106 is uniformly radiated into the heating chamber 103, and is not limited to a rectangular shape.

  In the microwave heating apparatus of the first embodiment, the waveguide 106 is disposed below the heating region (mounting portion 104) that is the bottom surface of the heating chamber 103, and the microwave transmission direction MT of the waveguide 106 is increased. Corresponds to the horizontal direction of the heating chamber 103. Further, the center line (tube axis) extending in the microwave transmission direction MT in the waveguide 106 is configured to overlap with the center line in the left-right direction on the bottom surface (heating region) of the heating chamber 103 above and below the center line.

  In the microwave heating apparatus of the first embodiment configured as described above, the radiation port 108a of the microwave radiation unit 108 is formed on the upper wall surface portion of the waveguide 106 facing the heating chamber (heating region). In this configuration, microwaves existing in the waveguide 106 are radiated from the opening to the heating chamber 103 to heat the object to be heated by microwaves.

  Next, the operation in the microwave heating apparatus of the first embodiment will be described. First, a schematic operation in the microwave heating apparatus will be described.

  A user arranges the object to be heated 102 on the mounting portion 104 in the heating chamber 103, sets the heating conditions, and gives a heating start instruction. When a heating start instruction is given by the user, the microwave heating apparatus supplies the microwave into the waveguide 106 by exciting the magnetron that is the microwave supply unit 105. In the waveguide 106 supplied with the microwave, the supplied microwave is reflected by the terminal end portion 107 of the waveguide 106, and as shown in FIG. A standing wave SW is generated.

  In the microwave heating apparatus of the first embodiment, a radiation port 108a that is an opening of the microwave radiation unit 108 is provided in the vicinity of a node of the standing wave SW formed as a microwave supply source. That is, the opening of the microwave radiating portion 108 is formed on the vertical line of the node position NP of the standing wave SW generated in the waveguide 106. The microwave radiating unit 108 formed as described above radiates microwaves from the waveguide 106 into the heating chamber 103, so that the microwave heating apparatus according to the first embodiment is heated in the heating chamber 103. Microwave heating is performed on 102.

  Next, the node position NP of the standing wave SW formed in the waveguide 106 will be described. As shown in FIG. 3B, when microwaves from the microwave supply unit 105 are supplied to the waveguide 106 having the terminal unit 107 which is a closed terminal, a predetermined shape is introduced. A standing wave SW is generated in the waveguide 106 by being transmitted through the wave tube 106 and reflected by the terminal end 107 of the waveguide 106.

  Since the waveguide 106 is closed at the terminal end 107, the amplitude at the terminal end 107 is fixed to zero. On the other hand, the supply side of the microwave supply unit 105 as shown in FIG. 1 is considered to be a free end indicating the maximum amplitude value as shown in FIG. For this reason, the wavelength of the standing wave SW generated in the waveguide 106 uses c which is the length of the microwave transmission direction MT shown in FIG. 3A and a natural number s indicating the standing wave mode. Thus, it can be simply calculated by the following equation (2). Note that the length c indicates a microwave transmission distance from the output end of the microwave supply unit 105 to the terminal end 107 of the waveguide 106.

  For example, when the length c of the microwave transmission direction MT in the waveguide 106 is 346 mm and λ is λn by applying the above formula (2), the wavelength λn of the standing wave SW formed in the waveguide 106, The interval (λn / 2) of the standing wave SW is as shown in the following (Table 1). Here, the interval between the standing waves SW is the length from node to node in the standing wave SW.

  The standing wave SW formed in the waveguide 106 is based on the microwave having the oscillation frequency supplied from the microwave supply unit 105, and the microwave having the oscillation frequency is the rectangular waveguide 106. By transmitting through the inside, a microwave having a transmission frequency is generated, and the microwave having the transmission frequency is reflected to generate a standing wave SW. Therefore, it is natural that the waveform of the standing wave SW formed in the waveguide 106 is similar to the transmission waveform transmitted from the microwave supply unit 105 through the waveguide 106. The waveform is most likely to exist in the waveguide 106 most stably. When the wavelength output from the microwave supply unit 105 is λ (λ = (speed of light) / (oscillation frequency)) and the cutoff wavelength, which is the maximum wavelength (minimum frequency) that can be transmitted in the waveguide 106, is λc, A transmission wavelength λg of a wave transmitted through the wave tube 106 is expressed by the following equation (3). The cutoff wavelength λc is determined by λc = 2 × a (a is the width of the waveguide 106). Here, the width a of the waveguide 106 means a length orthogonal to the microwave transmission direction MT of the waveguide 106 on the wall surface of the waveguide 106 where the microwave radiating portion 108 is provided.

  For example, when the oscillation frequency of the microwave supply unit 105 is 2.46 [GHz] and the width a of the waveguide 106 is 100 [mm], when these numerical values are substituted into Equation (3), the transmission wavelength is λg = 153.86 [mm]. Therefore, from the above-mentioned (Table 1), the standing wave SW in which the standing wave mode is s = 5 and the interval (λn / 2) of the standing wave SW is 76.9 [mm] is the waveguide 106. Formed. As a result, a standing wave SW having nodes and antinodes as shown in FIG.

  However, in the actual waveguide 106, if the output state of the microwave supply unit 105 and the waveguide 106 or the state of the termination 107 in the waveguide 106 is not an ideal state, the calculation is performed. The state of the standing mode of the value before and after the value can also be taken. For example, in such a case, the standing wave mode can take a state of s = 4 or s = 6. Therefore, the wavelength of the standing wave SW actually existing in the waveguide 106 is preferably confirmed by actually measuring the amplitude of the standing wave SW in the waveguide 106.

  According to the inventor's experiment, the standing wave SW generated in the waveguide 106 is stably present even after the microwave is radiated into the heating chamber 103 from the radiation port 108a of the microwave radiation unit 108. In other words, the waveguide 106 is configured such that the wavelength λn of the standing wave SW is the same as the state of the microwave transmitted through the waveguide 106, that is, the same value as the transmission wavelength λg. It was confirmed that it was preferable. By configuring the waveguide 106 in this way, a standing wave SW having the same wavelength as the transmission wavelength λg transmitted in the waveguide 106 is generated, and thus an inconsistent state occurs in the waveguide 106. There is no, and it becomes the most stable waveform state. Therefore, in the waveguide 106, when determining c (the microwave transmission distance from the output end of the microwave supply unit 105 to the terminal end 107 of the waveguide 106), which is the length in the microwave transmission direction MT, In the following formula (4) obtained by modifying the above formula (2), the transmission wavelength λg (≈λn: 153.86 [mm] in the first embodiment) is used as the wavelength λ, and the standing wave By substituting the standing wave state (s = 5 in the first embodiment) desired to be present in the waveguide 106 into the mode s, microwave radiation is performed from the microwave radiation unit 108. However, it is possible to create a condition in which a stable standing wave SW can be maintained in the waveguide 106.

  As described above, in the microwave heating apparatus according to the first embodiment, the object to be heated 102 placed on the placement unit 104 (heating region) in the heating chamber 103 from the radiation port 108a of the microwave radiation unit 108 is applied. On the other hand, the microwave that is the basis of the energy radiated is a standing wave SW of the microwave existing in the waveguide 106 below the heating chamber 103. The distribution of the standing wave SW generated in the waveguide 106 (arrangement of the antinodes and nodes of the standing wave SW) is uniformly formed in the waveguide 106, and a plurality of distributions corresponding to the standing wave distribution are provided. The microwave outlet 108 a of the microwave radiating section 108 is disposed in the waveguide 106. By radiating microwaves into the heating chamber 103 from the radiation openings 108 a of these microwave radiating portions 108, the heating distribution on the object to be heated 102 in the heating chamber 103 can be made uniform.

  In the microwave heating apparatus of the first embodiment, the center position of the radiation port 108a of the microwave radiation unit 108 corresponds to the node of the standing wave SW in the waveguide 106, that is, the position where the amplitude is substantially zero. I am letting. Note that the center position of the radiation port 108a of the microwave radiating portion 108 indicates the position of the center of gravity of the plate material when the shape of the radiation port 108a is assumed to be configured by a plate material having the same thickness.

  As described above, by setting the center position of the radiation port 108a of the microwave radiation unit 108 to a position corresponding to a node where the amplitude of the standing wave SW is substantially zero, the radiation port 108a of the microwave radiation unit 108 is obtained. Therefore, it is possible to prevent excessive microwave output from the heating chamber 106 to radiate the microwave to the object to be heated 102 more uniformly.

  In the microwave heating apparatus of the first embodiment, the waveguide 106 is arranged so that the microwave transmission direction MT of the waveguide 106 is the left-right direction on the bottom surface of the heating chamber 103 as shown in FIG. It is provided directly under the heating chamber 103. Further, the waveguide 106 is arranged so that the central axis extending in the transmission direction of the waveguide 106 overlaps in the vertical direction with respect to the central axis extending in the left-right direction of the bottom surface of the heating chamber 103.

  Further, in the microwave heating apparatus of the first embodiment, there are an even number of antinodes of the standing wave SW in a region overlapping the upper and lower sides of the region occupied by the heating chamber 103 and the region occupied by the waveguide 106. The position of the node NP of the standing wave SW is configured to correspond to the approximate center of the bottom surface (mounting unit 104) of the heating chamber 103. In the example shown in FIG. 3B, there are four antinodes of the standing wave SW in a region overlapping above and below the region occupied by the heating chamber 103 and the region occupied by the waveguide 106. Then, the bottom surface of the heating chamber 106 is located at the position of the node NP at the center of the four antinode standing waves SW existing in the region overlapping the region occupied by the heating chamber 103 and the region occupied by the waveguide 106. The center positions of the microwave radiating portions 108 that are present at substantially the center of the (mounting portion 104) are arranged so as to substantially correspond to each other.

  As described above, by arranging the microwave radiating unit 108 in the vicinity of the node of the standing wave SW, the microwave radiating unit 108 radiates in the central region where the object to be heated 102 is often placed in the heating chamber 103. The mouth 108a is provided, and highly efficient microwave heating can be realized.

  In the heating chamber 103, the radiation opening 108 a of the microwave radiating unit 108 disposed in a region near the wall surface and the radiation port 108 a of the microwave radiating unit 108 disposed in the central region are reflected to the heating chamber 103. Depending on the influence, the radiation amount may be different even with the same shape and size.

  In this case, each microwave radiating section 108 radiates from each microwave radiating section 108 by changing the opening area of the radiating opening 108a of each microwave radiating section 108 to increase or decrease for each node position of the standing wave SW. You may respond | correspond as a shape where the amount of microwaves becomes substantially the same. With this configuration, a microwave with a uniform microwave amount is applied to the heating chamber 106 from the radiation port 108a of each microwave radiation unit 108 formed near the node of the standing wave SW in the waveguide 106. Radiation can be performed.

  In the microwave heating apparatus of the first embodiment, the shape of the opening of the microwave radiating unit 108 has been described as the rectangular shape shown in FIG. 3C, but as the microwave radiating unit 108 in the present invention, The shape is not limited to such an opening shape, and any shape that can efficiently radiate microwaves from the waveguide 106 may be used.

  Further, in the microwave heating apparatus of the first embodiment, the microwave transmission distance c from the output end of the microwave supply unit 105 to the termination unit 107 in the waveguide 106 is set to a quarter of the transmission wavelength λg that is the guide wavelength. An integer multiple of 1 (λg / 4) is preferable. In this way, by setting the microwave transmission distance c to an integral multiple of one-fourth (λg / 4) of the transmission wavelength λg, particularly an odd multiple, harmony with the waveguide 106 can be achieved and stable within the waveguide 106. Thus, the standing wave SW having the same wavelength as the transmission wavelength λg can be generated. As a result, even when microwave radiation is performed from the microwave radiation unit 108 to the heating chamber 103, the standing wave can be stably maintained in the waveguide 106.

  As described above, in the microwave heating apparatus of the first embodiment, the end of the microwave transmission direction MT in the waveguide 106 is set so as to generate a standing wave having a predetermined wavelength in the waveguide 106. The waveguide 106 is closed and has a predetermined shape. Further, the standing wave SW generated in the waveguide 106 is arranged substantially symmetrically with respect to the center of the heating region (104) in the heating chamber 103, and the distance between the centers of the plurality of microwave radiating portions 108 is guided. The interval between the standing waves SW generated in the wave tube 106 (interval between the nodes NP and NP) is substantially the same. In the microwave heating apparatus according to the first embodiment configured as described above, the microwave from the microwave radiating unit 108 that radiates the heated object 102 disposed in the heating chamber 103 is introduced into the waveguide 106. The generated standing wave SW is arranged substantially evenly with respect to the heating chamber 103, and the microwave radiating portion 108 is arranged at a predetermined position corresponding to the standing wave distribution. Can be microwave heated.

  The microwave heating apparatus according to the first embodiment is configured so that the position of the node of the standing wave SW generated in the waveguide 106 corresponds to the center of the heating region of the heating chamber 103. Uniform microwave radiation can be performed from the radiation port 108 a of the radiation unit 108 to the heating chamber 103.

  In the microwave heating apparatus of the first embodiment, since the microwave radiating unit 108 is arranged corresponding to the position of the node NP of the standing wave SW generated in the waveguide 106, the microwave radiating unit Excessive output from 108 can be prevented, and microwave radiation can be performed more uniformly to the heating chamber 103.

  In the microwave heating apparatus of the first embodiment, the amount of microwaves radiated from each radiation port 108a is made substantially the same by increasing or decreasing the opening area of the radiation port 108a of each microwave radiation unit 108. You may comprise. In the microwave heating apparatus configured as described above, the amount of microwaves radiated from the plurality of microwave radiation units to the object to be heated can be made uniform.

  Furthermore, in the microwave heating apparatus of the first embodiment, the standing wave SW having an even number of antinodes is formed in a region in the waveguide 106 facing the heating region (104) in the heating chamber 103. Since the microwave radiating portion 108 is arranged corresponding to the node NP of the standing wave SW, the microwave is radiated evenly to the heating chamber 103 in the microwave transmission direction MT in the waveguide 106. . In particular, with such a configuration, microwaves are efficiently radiated to the object to be heated 102 disposed at the center of the heating chamber 103, and the heat treatment can be performed uniformly.

(Embodiment 2)
Hereinafter, the microwave heating apparatus according to the second embodiment of the present invention will be described. The microwave heating apparatus of the second embodiment is different from the microwave heating apparatus of the first embodiment described above in that the microwave radiating unit specifies a configuration that radiates circularly polarized waves. The same.

  In the description of the microwave heating apparatus of the second embodiment below, the same reference numerals are given to the components having the same functions and configurations as those in the microwave heating apparatus of the first embodiment, and the detailed description thereof is carried out. The description of Form 1 is applied.

  FIG. 4 is a plan view showing the arrangement state of the waveguide 106 with respect to the heating chamber 103 in the microwave heating apparatus of the second embodiment, and is a view of the waveguide 106 as viewed from above. In FIG. 4, the heating chamber 103 is indicated by a one-dot chain line, and the microwave radiating unit 108 is indicated by a two-dot chain line. In FIG. 4, the microwave radiating portion 108 indicated by a two-dot chain line is indicated by a rectangular region. However, this rectangular region does not specify the shape of the microwave radiating portion 108, and the opening of the microwave radiating portion 108 is simply defined. It shows the formation area to be formed.

  Hereinafter, the operation and action of the microwave heating apparatus of the second embodiment will be described. However, the basic operation of the microwave heating apparatus of the second embodiment is the same as that of the first embodiment, and is omitted here.

  In the microwave heating apparatus according to the second embodiment, the microwave radiating unit 108 arranged in the vicinity of the node of the standing wave SW existing in the waveguide 106 radiates circularly polarized waves as shown in FIG. have. Circular polarization is a technology widely used in the field of mobile communication and satellite communication. Examples of familiar use include ETC (Electronic Toll Collection System) “non-stop automatic toll collection system”.

  Circular polarization is a microwave in which the polarization plane of the electric field rotates with respect to the traveling direction of the radio wave according to time. When the circular polarization is formed, the direction of the electric field continues to change with time. The radiation angle of the microwave radiated into the inside continues to change, and the electric field strength does not change with time.

  The microwave heating apparatus according to the second embodiment is configured such that circularly polarized microwaves are radiated from the respective microwave radiating units 108 into the heating chamber 103. In the microwave heating apparatus according to the second embodiment configured as described above, the microwave is dispersed over a wide range in the heating chamber 103 as compared with the microwave heating by the linearly polarized wave used in the microwave heating apparatus. Therefore, the object to be heated 102 placed in the heating chamber 103 can be uniformly heated by microwaves.

  In particular, when a circularly polarized microwave is radiated, the tendency of uniform heating is strong in the circumferential direction of the circularly polarized wave. Note that circularly polarized waves are classified into two types from the rotation direction: right-handed polarization (CW: clockwise) and left-handed polarization (CCW: counter clockwise). Whether the circularly polarized microwave radiated into the heating chamber 102 is right-handed polarized wave (CW) or left-handed polarized wave (CCW), there is no difference in heating performance.

  In the microwave heating apparatus of the second embodiment, the center position of the radiation port 108b, which is the opening of the microwave radiating unit 108, is fixed in the waveguide 106, as in the microwave heating apparatus of the first embodiment. It is arranged in the vicinity of the node of the standing wave SW, that is, the position corresponding to the position where the amplitude is substantially zero. Thus, since the center position of the radiation port 108b of the microwave radiation unit 108 is in the vicinity of the position corresponding to the node where the amplitude of the standing wave SW is substantially zero, the microwave radiation unit 108 is heated to the heating chamber. The excessive microwave output to 106 can be prevented, and the microwave to the object to be heated 102 can be radiated more uniformly.

  As described above, in the microwave heating apparatus according to the second embodiment, the microwave that is the base of the energy radiated from the microwave radiating unit 108 into the heating chamber 103 is transmitted in the waveguide 106 below the heating chamber 103. Standing wave SW. The distribution of the standing wave SW (arrangement state of the antinodes and nodes of the standing wave SW) is evenly formed in the waveguide 106, and a plurality of microwave radiating portions corresponding to the standing wave distribution. 108 is disposed in the waveguide 106. The circularly polarized microwave is radiated into the heating chamber 103 from these microwave radiating portions 108, whereby the heating distribution on the object to be heated 102 in the heating chamber 103 can be made uniform.

  In the microwave heating apparatus of the second embodiment, the configuration of the microwave radiating unit 108 is not particularly limited as long as it has a configuration that radiates circularly polarized waves. An example of the shape will be described with reference to FIG. FIG. 4 shows a specific opening shape formed in the region of the microwave radiation unit 108 used in the microwave heating apparatus of the second embodiment. The microwave radiating portion 108 shown in FIG. 4 is formed on the surface of the waveguide 106 that faces the heating chamber 103. The microwave radiating portion 108 has an opening that radiates circularly polarized microwaves in the region of the microwave radiating portion 108. A certain radiation port 108b is formed. The radiating port 108b is configured by intersecting two slits (elongated opening portions) having a width at the center, and each slit is inclined by 45 degrees with respect to the microwave transmission direction MT of the waveguide 106. Yes. The radiation port 108b is formed at a position shifted from the tube axis P extending in the microwave transmission direction MT of the waveguide 106 by a predetermined distance in the microwave radiating unit 108, and does not pass directly above the tube axis P. Need to be placed in. In the microwave heating apparatus of the second embodiment, the radiation ports 108b of the microwave radiation units 108 are alternately arranged (asymmetrically arranged) at the front and rear positions of the tube axis P, and the respective microwave radiation units 108 are arranged. It is configured to radiate right-handed polarization CW or left-handed polarization CCW.

  As described above, in the microwave heating apparatus according to the second embodiment, the radiation opening 108b in the microwave radiating unit 108 is shaped to radiate circularly polarized waves (including elliptically polarized waves), thereby radiating microwaves. A microwave having a spread is emitted from the portion 108. As a result, the microwave heating apparatus of the second embodiment has a configuration capable of making the microwave radiation to the object to be heated 102 uniform over a wider range.

  In the microwave heating apparatus according to the second embodiment, the microwave radiating unit 108 that radiates circularly polarized waves has been described with the configuration of the radiating port 108b in which two slits intersect. The configuration is not limited, and any shape that radiates circularly polarized waves (including elliptically polarized waves) may be used.

  As described above, in the microwave heating apparatus according to the second embodiment, the microwave radiating unit 108 includes the radiation port 108 b that is an opening that radiates microwaves, and the radiation port 108 b is the microwave in the waveguide 106. They are arranged asymmetrically with respect to the tube axis P in the transmission direction MT. The microwave heating apparatus according to the second embodiment configured as described above can perform uniform microwave radiation to the heating chamber 103 in a wider range.

(Embodiment 3)
Hereinafter, the microwave heating apparatus according to the third embodiment of the present invention will be described. In the microwave heating apparatus of the third embodiment, the difference from the microwave heating apparatus of the first embodiment described above is that the microwave radiating unit is configured to radiate circularly polarized waves, and the other points are as follows. The same. The basic operation of the microwave heating apparatus of the third embodiment is the same as that of the microwave heating apparatus of the first embodiment.

  In the description of the microwave heating apparatus of the third embodiment below, the same reference numerals are given to the components having the same functions and configurations as the components in the microwave heating apparatus of the first embodiment, and the detailed description thereof is carried out. The description of Form 1 is applied.

  FIG. 5 is a plan view showing the arrangement state of the waveguide 106 with respect to the heating chamber 103 in the microwave heating apparatus of the third embodiment, and is a view of the waveguide 106 as viewed from above. In FIG. 5, the heating chamber 103 is indicated by a one-dot chain line, and the microwave radiating unit 108 is indicated by a two-dot chain line. In FIG. 5, the microwave radiating portion 108 indicated by a two-dot chain line is indicated by a rectangular region. However, this rectangular region does not specify the shape of the microwave radiating portion 108, and the opening of the microwave radiating portion 108 is simply defined. It shows the formation area to be formed.

  In the microwave heating apparatus of the third embodiment, the waveguide 103 is provided with a radiation port 108c of the microwave radiating unit 108 that radiates circularly polarized waves, like the microwave heating apparatus of the second embodiment described above. . However, in the microwave heating apparatus of the third embodiment, each microwave radiating unit 108 is provided with a radiating port 108 c at a position symmetrical to the tube axis P. Thus, by arranging the radiation openings 108 c symmetrically, the microwaves of right-handed polarization CW and left-handed polarization CCW are radiated into the heating chamber 103 from the regions of the respective microwave radiation portions 108. As described above, in the microwave heating apparatus according to the third embodiment, each of the microwave radiating units 108 has the configuration in which the two radiation ports 108c and 108c are provided at positions symmetrical to the tube axis P. The microwave radiation can be further expanded in the front-rear direction (the direction from the front side to the back side of the heating chamber 103) of the heating chamber 103 orthogonal to the microwave transmission direction MT. Further, in the microwave heating apparatus of the third embodiment, since the microwaves of right-handed polarized wave CW and left-handed polarized wave CCW are radiated from the regions of the respective microwave radiating units 108, The microwave expansion effect can be further enhanced.

  As described above, in the microwave heating apparatus of the third embodiment, the opening serving as the radiation port 108c of the microwave radiation unit 108 is symmetric with respect to the tube axis P of the waveguide 106 in the microwave transmission direction MT. By forming the arrangement, microwave radiation can be further spread in the front-rear direction of the device orthogonal to the microwave transmission direction MT of the waveguide 106, and the microwave radiation to the heating chamber 103 is further uniformized, High efficiency microwave heating can be performed by uniformly irradiating the article to be heated 102.

  As described above, in the microwave heating apparatus according to the third embodiment, the microwave radiating unit 108 includes the radiation port 108 c that is an opening that radiates microwaves, and the radiation port 108 c is microwave transmission in the waveguide 106. They are arranged symmetrically with respect to the tube axis P extending in the direction MT. The microwave heating apparatus according to the third embodiment configured as described above can evenly radiate microwaves even to the heating region (104) in the direction orthogonal to the microwave transmission direction MT in the waveguide 106. Can do.

  In the microwave heating apparatus of the third embodiment, since the radiation port 108b of the microwave radiating unit 108 is configured to radiate circularly polarized waves, a microwave having a spread from the microwave radiating unit 108 is generated. The microwave radiation can be made uniform with respect to the object to be heated 102 in a wider range.

  As described above, in the microwave heating apparatus of the present invention, the standing wave wavelength of the standing wave generated in the waveguide is the microwave transmission wavelength supplied from the microwave supply unit and transmitted through the waveguide. The waveguide is configured to be substantially equal. The microwave heating device of the present invention configured as described above can reliably generate a desired standing wave in the waveguide.

  In the microwave heating apparatus of the present invention, the microwave transmission distance (c) from the output end of the microwave supply unit to the end of the waveguide is supplied from the microwave supply unit and transmitted through the waveguide. It is an integral multiple of a quarter of the microwave transmission wavelength (λg). The microwave heating apparatus of the present invention configured as described above can generate a standing wave (SW) having the same wavelength as the transmission wavelength (λg) of the microwave stably transmitted in the waveguide. Therefore, even when microwave radiation is performed from the microwave radiation portion, the standing wave in the waveguide can be stably maintained.

  As described above, the microwave heating apparatus according to the present invention is configured so that the microwave from the microwave radiating unit that radiates the object to be heated disposed in the heating chamber is a standing wave generated in the waveguide. Since the microwave radiating portions are arranged corresponding to the standing wave distribution, the object to be heated can be uniformly heated by microwaves.

  Since the microwave heating apparatus of the present invention can uniformly irradiate the object to be heated with microwaves, the microwave heating apparatus can be effectively used for an apparatus for performing heat processing or sterilization, and also uses dielectric heating. The present invention can be applied to a microwave heating apparatus in various devices such as a heating apparatus, a garbage disposal machine, and a semiconductor manufacturing apparatus.

DESCRIPTION OF SYMBOLS 101 Case 102 Object to be heated 103 Heating chamber 104 Placement part 105 Microwave supply part 106 Waveguide 107 Termination part 108 Microwave radiation part

Claims (13)

A heating chamber in which an object to be heated is arranged;
A microwave supply unit for generating microwaves to be supplied to the heating chamber;
A waveguide for transmitting the microwave generated by the microwave supply unit to the heating chamber;
A plurality of microwave radiation portions for radiating microwaves transmitted through the waveguide to the heating chamber,
In order to generate a standing wave having a predetermined wavelength in the waveguide, the end of the waveguide in the microwave transmission direction is closed, and the waveguide has a predetermined shape,
A microwave heating apparatus in which a distribution of standing waves generated in the waveguide is arranged substantially symmetrically with respect to a center of a heating region in the heating chamber.   The microwave heating apparatus according to claim 1, wherein the plurality of microwave radiating portions are disposed substantially symmetrically with respect to a center of the heating region.   The said microwave radiation part is provided in the said waveguide so that the distance between the centers of these microwave radiation parts may become substantially the same as the space | interval of the standing wave which generate | occur | produced in the waveguide. Microwave heating device.   The microwave heating apparatus according to claim 3, wherein a position of a node of a standing wave generated in the waveguide corresponds to a center of a heating region of the heating chamber.   The microwave heating device according to claim 4, wherein the microwave radiating unit is disposed corresponding to a position of a node of a standing wave generated in the waveguide.   The microwave heating apparatus according to claim 5, wherein a standing wave having an even number of antinodes is formed in a region in the waveguide facing the heating region in the heating chamber.   The microwave heating device according to claim 6, wherein the microwave radiating unit includes an opening that radiates microwaves, and the opening is arranged symmetrically with respect to a tube axis extending in a microwave transmission direction in the waveguide. .   The microwave heating apparatus according to claim 6, wherein the microwave radiating unit is configured by an opening that radiates microwaves, and the opening is asymmetrically arranged with respect to a tube axis in a microwave transmission direction in the waveguide.   The microwave heating device according to any one of claims 1 to 8, wherein the microwave amount radiated from the microwave radiating unit is configured to be substantially the same.   The waveguide is configured such that the standing wave wavelength of the standing wave generated in the waveguide is substantially equal to the transmission wavelength of the microwave supplied from the microwave supply unit and transmitted through the waveguide. The microwave heating device according to any one of claims 1 to 8.   The microwave heating device according to any one of claims 1 to 8, wherein the microwave radiating unit is configured to radiate circularly polarized waves.   The microwave transmission distance from the output end of the microwave supply unit to the end of the waveguide is an integer of a quarter of the transmission wavelength of the microwave supplied from the microwave supply unit and transmitted through the waveguide. The microwave heating device according to any one of claims 1 to 8, wherein the microwave heating device is doubled. The waveguide is a rectangular waveguide, and the supply wavelength supplied from the microwave supply unit is λ, and the waveguide micro wave on the wall surface of the waveguide provided with the microwave radiation unit is provided. Assuming that the length orthogonal to the wave transmission direction is a, the standing wave wavelength λn of the standing wave generated in the waveguide is transmitted through the waveguide expressed by the following formula (1). The microwave heating device according to any one of claims 1 to 8, wherein the microwave heating device is configured to be substantially equal to the wavelength λg.

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