JP2015201344A - microwave heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave heating device which prevents a failure in a microwave radiation source and is capable of efficiently using microwave energy for heating a specimen.SOLUTION: On a circumference with a reactor 1 as a central part, a plurality of microwave radiation sources 4 are provided. For one microwave radiation source 4, the other microwave radiation source 4 is disposed at a position deviated from an opposing position via the reactor 1. Between the microwave radiation sources 4 on the circumference where the microwave radiation sources 4 are disposed, a plurality of sub reflectors 5 are provided. The sub reflector 5 is disposed at a position facing the microwave radiation source 4 via the reactor 1. Thus, a microwave II that is reflected without being absorbed by a specimen 21, is reflected by the sub reflector 5 and the specimen 21 is irradiated again therewith. Therefore, a failure in the microwave radiation source 4 is prevented and microwave energy can be efficiently used for heating the specimen 21.

Description

  The present invention relates to a microwave heating apparatus that heats a sample by irradiating it with microwaves.

  In the field of microwave transmission technology, for example, various technologies related to high-efficiency transmission technology and beam control technology using an active phased array antenna (APAA) for the realization of a solar power satellite (SPS). R & D is underway.

  There is also a trend to apply these microwave transmission technologies to industrial applications. For example, Patent Document 1 and Patent Document 2 disclose an iron manufacturing system that manufactures molten pig iron by irradiating and heating a raw material with microwaves. Non-Patent Document 1 discloses a technique for configuring a microwave radiation source with a phased array antenna in an iron-making system using microwaves. Furthermore, recently, a technique for shortening a chemical reaction time by applying a microwave to a chemical reaction is also attracting attention.

  At present, microwave transmission technology is often applied to small-scale devices. However, development of large-scale and high-power devices such as an iron manufacturing system is also demanded.

International Publication No. 2010/087464 JP2013-11384A

Sato, Nagata, Shinohara, Mitani, Kashimura, “Conceptual design of industrial microwave applicator using phased array antenna”, Proceedings of the 5th Symposium of Japan Electromagnetic Energy Application Society, 2011, pp. 98-99

  The conventional iron manufacturing systems disclosed in Patent Document 1, Patent Document 2, and Non-Patent Document 1 have microwave radiation sources arranged circumferentially around a reaction furnace. For this reason, of the microwaves radiated from a specific microwave radiation source (hereinafter referred to as “first microwave radiation source”), the microwaves that are not absorbed by the sample to be heated are reflected by this sample and reacted. A microwave radiation source (hereinafter referred to as a “second microwave radiation source”) facing the first microwave radiation source is irradiated through a furnace. Thereby, there was a problem that a failure of the second microwave radiation source occurred.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a microwave heating apparatus that can prevent a failure of a microwave radiation source.

  A microwave heating apparatus according to the present invention includes a sample stage housed in a reaction furnace and having a sample mounting surface, a main reflecting mirror disposed opposite to the sample mounting surface, and a main reflecting mirror facing the main reflecting mirror. A plurality of microwave radiation sources arranged around and irradiating the sample mounting surface with microwaves, and the microwave radiation sources are located at positions shifted from positions facing each other through the reactor. A radiation source is arranged.

  According to the microwave heating apparatus of the present invention, failure of the microwave radiation source can be prevented.

It is explanatory drawing which shows the structure seen from the upper surface of the microwave heating device of Embodiment 1 of this invention. It is explanatory drawing which shows the structure seen from the cross section along the A-A 'line | wire of the microwave heating apparatus shown in FIG. It is explanatory drawing which shows the structure seen from the upper surface of the other microwave heating apparatus of Embodiment 1 of this invention. It is explanatory drawing which shows the structure seen from the upper surface of the other microwave heating apparatus of Embodiment 1 of this invention. It is explanatory drawing which shows the structure seen from the upper surface of the microwave heating device of Embodiment 2 of this invention. It is explanatory drawing which shows the structure seen from the cross section along the A-A 'line | wire of the microwave heating apparatus shown in FIG. It is explanatory drawing which shows the structure seen from the upper surface of the other microwave heating apparatus of Embodiment 2 of this invention. It is explanatory drawing which shows the structure of the subreflective mirror of Embodiment 3 of this invention. It is explanatory drawing which shows the structure seen from the upper surface of the microwave heating device of Embodiment 3 of this invention. It is explanatory drawing which shows the structure seen from the cross section along the A-A 'line | wire of the microwave heating apparatus shown in FIG. It is explanatory drawing which shows the structure seen from the upper surface of the microwave heating device of Embodiment 4 of this invention. It is explanatory drawing which shows the structure seen from the cross section along the A-A 'line | wire of the microwave heating apparatus shown in FIG. It is explanatory drawing which shows the structure seen from the upper surface of the microwave heating device of Embodiment 5 of this invention. It is explanatory drawing which shows the structure seen from the cross section along the A-A 'line | wire of the microwave heating apparatus shown in FIG.

Embodiment 1 FIG.
With reference to FIG.1 and FIG.2, the microwave heating apparatus of Embodiment 1 of this invention is demonstrated.
In the figure, 1 is a reactor. The reaction furnace 1 has an opening 11 in which a sample stage 2 is accommodated. A sample 21 to be heated is placed on the sample stage 2.

  The main reflecting mirror 3 is disposed so as to face the mounting surface (sample mounting surface) 22 of the sample 21. The shape of the main reflecting mirror 3 is a rotationally symmetric shape with respect to the central axis along the line B-B ′.

  A plurality of microwave radiation sources 4 facing the main reflecting mirror 3 are provided around the reaction furnace 1. In the microwave radiation source 4, another microwave radiation source 4 is arranged at a position shifted from the position facing the reactor 1.

  A plurality of sub-reflecting mirrors 5 facing the main reflecting mirror 3 are provided around the reaction furnace 1. The sub-reflecting mirror 5 is disposed at a position facing the microwave radiation source 4 through the reaction furnace 1.

  Here, the microwave radiation source 4 is arranged on a circumference centering on the reaction furnace 1. The sub-reflecting mirror 5 is disposed between the microwave radiation sources 4 on the circumference where the microwave radiation source 4 is disposed. That is, as shown in FIG. 1, a microwave radiation source 4 is disposed at one end and a pair of sub-reflecting mirrors 5 are disposed at the other end along the line AA ′ along the diameter of the circumference. .

With reference to FIG. 2, the operation of the microwave heating apparatus 100 configured as described above will be described.
First, as indicated by a solid arrow, the microwave radiation source 4 radiates the microwave I toward the main reflecting mirror 3. The main reflecting mirror 3 reflects the radiated microwave I and converges it on the central portion 23 of the mounting surface 22 of the sample table 2. Thereby, the microwave I is irradiated to the sample 21 placed on the mounting surface 22, and the sample 21 is heated.

  At this time, a part of the microwave I irradiated to the sample 21 is absorbed by the heating reaction in the sample 21. The remaining microwave II that has not been absorbed is reflected in a direction symmetrical to the microwave I with respect to the central axis of the main reflecting mirror 3.

  The microwave II is reflected by the main reflecting mirror 3 and enters the sub-reflecting mirror 5. The sub-reflecting mirror 5 reflects the incident microwave II in the same direction as the incident direction. The reflected microwave III is reflected by the main reflecting mirror 3 and converges on the central portion 23 of the mounting surface 22 of the sample table 2. Thereby, the microwave III is again irradiated to the sample 21 placed on the mounting surface 22, and the sample 21 can be further heated.

  At this time, a part of the microwave III that has not been absorbed by the sample 21 may be reflected by the sample 21 and return to the microwave radiation source 4 again. However, the power of the microwave returning to the microwave radiation source 4 is sufficiently small due to the two absorptions in the sample 21 and the propagation loss in the propagation path reciprocating between the microwave radiation source 4 and the sub-reflection mirror 5. . Thereby, failure of the microwave radiation source 4 can be prevented.

As described above, the microwave heating apparatus 100 according to the first embodiment is provided with a plurality of microwave radiation sources 4 on the circumference centered on the reaction furnace 1. In the microwave radiation source 4, another microwave radiation source 4 is arranged at a position shifted from the position facing the reactor 1.
When another microwave radiation source 4 is disposed at a position facing the microwave radiation source 4 through the reactor 1, the microwave II reflected by the sample 21 causes the other microwave radiation source 4 to fail. End up. On the other hand, the failure of the other microwave radiation sources 4 can be prevented by arranging the other microwave radiation sources 4 at positions shifted from the facing positions as in the microwave heating device 100.

A plurality of sub-reflecting mirrors 5 are provided between the microwave radiation sources 4 on the circumference where the microwave radiation sources 4 are arranged. The sub-reflecting mirror 5 is disposed at a position facing the microwave radiation source 4 through the reaction furnace 1.
As a result, the microwave II reflected without being absorbed by the sample 21 is reflected by the sub-reflecting mirror 5 and irradiates the sample 21 again, thereby preventing the microwave radiation source 4 from being broken and reducing the microwave energy. The sample 21 can be efficiently used for heating.

  In addition, the number of arrangement | positioning of the microwave radiation source 4 is not limited to 15 pieces shown in FIG. Any number of microwave radiation sources 4 may be arranged. Further, the microwave radiation source 4 may be configured using an arbitrary type of antenna or the like. The frequency of the microwave radiated from the microwave radiation source 4 may be an arbitrary frequency depending on the material of the sample 21 and the temperature to be heated.

  Further, the shape of the main reflecting mirror 3 is not limited to the rotationally symmetric shape shown in FIGS. Any shape may be used as long as the microwave I and the microwave III are converged to a predetermined portion of the mounting surface 22. Further, the number of main reflecting mirrors 3 is not limited to one shown in FIGS. An arbitrary number of microwaves may be used as long as the microwaves I and III are converged to a predetermined part of the mounting surface 22.

  Moreover, the shape of the reactor 1 is not limited to the bottomed shape shown in FIG.1 and FIG.2. Depending on the shape and temperature characteristics of the sample 21, FIGS. 1 and 2 show a rectangular cross section. For example, a circular shape or a polygonal shape may be used.

  Further, the shape of the sub-reflecting mirror 5 is not limited to the shape shown in FIGS. Any shape that reflects the microwave III in the same direction as the incident direction of the microwave II may be used.

  Further, the arrangement of the microwave radiation source 4 and the sub-reflecting mirror 5 is not limited as long as the sub-reflecting mirror 5 is opposed to the microwave radiation source 4 via the reaction furnace 1, and is arranged on the circumference as shown in FIG. It is not limited to the arrangement provided alternately. For example, as shown in FIG. 3 or FIG. 4, a plurality of microwave radiation sources 4 may be arranged adjacently on the circumference, and a plurality of sub-reflecting mirrors 5 may be arranged adjacently on the circumference. .

  Moreover, the reaction furnace 1, the sample stage 2, the main reflecting mirror 3, and the sub-reflecting mirror 5 may be configured using arbitrary constituent materials.

Embodiment 2. FIG.
With reference to FIG.5 and FIG.6, the microwave heating apparatus which has arrange | positioned the microwave radiation source and the sub-reflecting mirror on the positive / odd square shape is demonstrated. In FIG. 5, a regular pentagon is drawn as an example of a regular odd-odd square. In addition, the same code | symbol is attached | subjected to the structural member similar to Embodiment 1, and description is abbreviate | omitted.

  The microwave radiation sources 4 are respectively arranged at the apexes of a regular pentagon with the reaction furnace 1 as the center. The sub-reflecting mirrors 5 are respectively disposed on the sides between the vertices of the regular pentagon where the microwave radiation source 4 is disposed.

  Generally, in a regular odd-odd square, the diagonal line does not pass through the center of the regular odd-odd square. Therefore, the microwave radiation source 4 disposed at the apex of the regular pentagon is disposed at a position shifted from the position facing the reactor 1 through the reaction furnace 1.

  In the case of a positive odd-numbered square, a line connecting the vertex and the midpoint of the side between the vertexes passes through the center of the positive-odd square. Accordingly, the sub-reflecting mirror 5 disposed on the side between the vertices of the regular pentagon is opposed to the pair of microwave radiation sources 4 disposed at the vertices of the regular pentagon via the reactor 1. Is arranged.

The microwave heating apparatus 200 configured as described above operates in the same manner as the microwave heating apparatus 100 of the first embodiment as follows.
In other words, the sample 21 is irradiated with the microwave I emitted from the microwave radiation source 4. The microwave II reflected by the sample 21 enters the sub-reflecting mirror 5. Microwave III reflected by the sub-reflecting mirror 5 in the same direction as the incident direction of the microwave II is irradiated again on the sample 21.

  By irradiating the sample 21 again with the microwave III reflected in the same direction as the incident direction of the microwave II by the sub-reflecting mirror 5, the energy of the microwave III can also be used for heating the sample 21. Moreover, since the microwave power returning to the microwave radiation source 4 is sufficiently small, failure of the microwave radiation source 4 can be prevented.

As described above, in the microwave heating apparatus 200 according to the second embodiment, the plurality of microwave radiation sources 4 are arranged at the apexes of a regular pentagon with the reaction furnace 1 as the center.
When another microwave radiation source 4 is disposed at a position facing the microwave radiation source 4 through the reactor 1, the microwave II reflected by the sample 21 causes the other microwave radiation source 4 to fail. End up. On the other hand, the failure of other microwave radiation sources 4 can be prevented by arranging the other microwave radiation sources 4 at the vertices of positive and odd squares as in the microwave heating device 200.

Further, the sub-reflecting mirror 5 is disposed on the side between the vertices of the regular pentagon where the microwave radiation source 4 is disposed.
As a result, the microwave II reflected without being absorbed by the sample 21 is reflected by the sub-reflecting mirror 5 and irradiates the sample 21 again, thereby preventing the microwave radiation source 4 from being broken and reducing the microwave energy. The sample 21 can be efficiently used for heating.

  In addition, the number of arrangement | positioning of the microwave radiation source 4 is not limited to 15 pieces shown in FIG. The microwave radiation source 4 may be disposed at the apex of an arbitrary positive / odd square having the reaction furnace 1 as the center, and the sub-reflecting mirror 5 may be disposed on the side between the apexes of the positive / odd square.

  Further, as shown in FIG. 7, the sub-reflecting mirror 5 is arranged at the apex of the positive / odd square having the reactor 1 as the center, and the microwave radiation source 4 is arranged on the side between the apexes of the positive / odd square. It may be a thing.

Embodiment 3 FIG.
With reference to FIGS. 8-10, the microwave heating apparatus which comprised the sub-reflection mirror with what is called a "three-surface corner reflector" is demonstrated. In addition, the same code | symbol is attached | subjected to the structural member similar to Embodiment 1, and description is abbreviate | omitted.

  As shown in FIG. 8, three plane mirrors 51 a to 51 c each having a right triangle shape that reflects microwaves are respectively along three planes (xz plane, xy plane, and yz plane) orthogonal to each other. By combining them, the sub-reflecting mirror 5a of the three-surface corner reflector is configured. The sub-reflecting mirror 5a reflects the incident microwave II once each by the plane mirrors 51a to 51c (that is, a total of three times) as shown by the white arrow, and finally the same as the incident direction of the microwave II. The microwave III is reflected in the direction.

  The sub-reflecting mirror 5 a is provided around the reaction furnace 1 so as to face the main reflecting mirror 3. The sub-reflecting mirror 5 a is disposed at a position facing the microwave radiation source 4 through the reaction furnace 1.

The microwave heating apparatus 300 configured as described above operates in the same manner as the microwave heating apparatus 100 of the first embodiment as follows.
In other words, the sample 21 is irradiated with the microwave I emitted from the microwave radiation source 4. The microwave II reflected by the sample 21 enters the sub-reflecting mirror 5a. The microwave III reflected by the sub-reflecting mirror 5a in the same direction as the incident direction of the microwave II is irradiated again on the sample 21.

  By irradiating the sample 21 again with the microwave III reflected by the sub-reflecting mirror 5a in the same direction as the incident direction of the microwave II, the energy of the microwave III can also be used for heating the sample 21. Moreover, since the microwave power returning to the microwave radiation source 4 is sufficiently small, failure of the microwave radiation source 4 can be prevented.

As described above, the microwave heating apparatus 300 according to the third embodiment has the sub-reflecting mirror 5a configured with the three-surface corner reflector.
As a result, the microwave II reflected without being absorbed by the sample 21 is reflected by the sub-reflecting mirror 5a and irradiates the sample 21 again, thereby preventing the microwave radiation source 4 from being damaged and reducing the energy of the microwave. The sample 21 can be efficiently used for heating.

  The sub-reflecting mirror 5a may be configured using a three-surface corner reflector having an arbitrary constituent material and dimensions.

  Further, the arrangement of the microwave radiation source 4 and the sub-reflecting mirror 5a is not limited to the arrangement on the circumference shown in FIG. As shown in FIG. 5 or FIG. 7, they may be arranged on positive and odd squares.

Embodiment 4 FIG.
With reference to FIG.11 and FIG.12, the microwave heating apparatus which comprised the microwave radiation source by what is called an "active phased array antenna" is demonstrated. In addition, the same code | symbol is attached | subjected to the structural member similar to Embodiment 1, and description is abbreviate | omitted.

  In the figure, reference numeral 41 denotes an array antenna unit. The array antenna unit 41 is configured by arranging a plurality of subarrays formed by arranging a plurality of antenna elements. An amplifier 42 and a phase shifter 43 are connected in series between each subarray and a power supply unit (not shown). The array antenna unit 41, the amplifier 42, and the phase shifter 43 constitute a microwave radiation source 4a of an active phased array antenna.

  The microwave radiation source 4a configured in this way changes the amplitude of the microwave radiated from the corresponding subarray by adjusting the amplification amount of the amplifier 42. Further, by adjusting the phase shift amount of the phase shifter 43, the phase of the microwave radiated from the corresponding sub-array changes.

  The microwave radiation source 4 a is provided around the reaction furnace 1 so as to face the main reflecting mirror 3. In the microwave radiation source 4a, another microwave radiation source 4a is disposed at a position shifted from a position facing the reactor 1 through the reaction furnace 1.

The microwave heating apparatus 400 configured as described above operates in the same manner as the microwave heating apparatus 100 of the first embodiment as follows.
That is, the microwave I emitted from the microwave radiation source 4a is applied to the sample 21. The microwave II reflected by the sample 21 enters the sub-reflecting mirror 5. Microwave III reflected by the sub-reflecting mirror 5 in the same direction as the incident direction of the microwave II is irradiated again on the sample 21.

  By irradiating the sample 21 again with the microwave III reflected in the same direction as the incident direction of the microwave II by the sub-reflecting mirror 5, the energy of the microwave III can also be used for heating the sample 21. Moreover, since the electric power of the microwave returning to the microwave radiation source 4a is sufficiently small, failure of the microwave radiation source 4a can be prevented.

  Furthermore, by adjusting the amplification amount of the amplifier 42 and the phase shift amount of the phase shifter 43 corresponding to each subarray, the irradiation distribution of the microwave I irradiated to the sample 21 can be controlled.

As described above, the microwave heating apparatus 400 according to the fourth embodiment has the microwave radiation source 4a configured by the active phased array antenna.
As a result, the microwave II reflected without being absorbed by the sample 21 is reflected by the sub-reflecting mirror 5 and irradiates the sample 21 again, thereby preventing the failure of the microwave radiation source 4a and reducing the microwave energy. The sample 21 can be efficiently used for heating.
Further, by adjusting the amplification amount of the amplifier 42 and the phase shift amount of the phase shifter 43, the irradiation distribution of the microwave I irradiated on the sample 21 can be flexibly controlled.

  The amplifier 42 and the phase shifter 43 may be connected between each antenna element and the power feeding unit instead of between each subarray and the power feeding unit.

  Further, the arrangement of the microwave radiation source 4a and the sub-reflecting mirror 5 is not limited to the arrangement on the circumference shown in FIG. As shown in FIG. 5 or FIG. 7, they may be arranged on positive and odd squares.

  Further, the sub-reflecting mirror 5 may be configured using a three-surface corner reflector shown in FIG.

Embodiment 5 FIG.
With reference to FIG.13 and FIG.14, the microwave heating apparatus which provided the heating means outside the reaction furnace is demonstrated. In addition, the same code | symbol is attached | subjected to the structural member similar to Embodiment 1, and description is abbreviate | omitted.

  A heating means 7 is provided outside the reaction furnace 1. The heating means 7 applies heat to the reaction furnace 1 from the outside, and is constituted by, for example, a heating device or a combustion device.

The microwave heating apparatus 500 configured as described above operates in the same manner as the microwave heating apparatus 100 of the first embodiment as follows.
In other words, the sample 21 is irradiated with the microwave I emitted from the microwave radiation source 4. The microwave II reflected by the sample 21 enters the sub-reflecting mirror 5. Microwave III reflected by the sub-reflecting mirror 5 in the same direction as the incident direction of the microwave II is irradiated again on the sample 21.

  By irradiating the sample 21 again with the microwave III reflected in the same direction as the incident direction of the microwave II by the sub-reflecting mirror 5, the energy of the microwave III can also be used for heating the sample 21. Moreover, since the microwave power returning to the microwave radiation source 4 is sufficiently small, failure of the microwave radiation source 4 can be prevented.

  Furthermore, in addition to irradiating the sample 21 with the microwave I and the microwave III, by heating the reaction furnace 1 from the outside by the heating means 7, the temperature inside the reaction furnace 1 is raised, The reaction rate of the heating reaction can be increased.

As described above, the microwave heating apparatus 500 according to the fifth embodiment is provided with the heating means 7 outside the reaction furnace 1.
As a result, the microwave II reflected without being absorbed by the sample 21 is reflected by the sub-reflecting mirror 5 and irradiates the sample 21 again, thereby preventing the microwave radiation source 4 from being broken and reducing the microwave energy. The sample 21 can be efficiently used for heating.
Furthermore, by heating the reaction furnace 1 from the outside by the heating means 7, the temperature inside the reaction furnace 1 can be raised and the sample 21 can be heated more efficiently.

  The heating means 7 may be constituted by any device or means as long as the temperature inside the reaction furnace 1 is sufficiently increased.

  Further, the arrangement of the microwave radiation source 4 and the sub-reflecting mirror 5 is not limited to the arrangement on the circumference shown in FIG. As shown in FIG. 5 or FIG. 7, they may be arranged on positive and odd squares.

  Further, the sub-reflecting mirror 5 may be configured using a three-surface corner reflector shown in FIG.

  The microwave radiation source 4 may be configured using an active phased array antenna.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Reactor, 2 Sample stand, 3 Main reflector, 4, 4a Microwave radiation source, 5, 5a Sub reflector, 7 Heating means, 11 Opening part, 21 Sample, 22 Mounting surface (sample mounting surface), 23 central part, 41 array antenna part, 42 amplifier, 43 phase shifter, 51a, 51b, 51c plane mirror, 100, 200, 300, 400, 500 microwave heating device.

Claims (7)

A sample stage housed in a reaction furnace and having a sample mounting surface;
A main reflector disposed opposite to the sample mounting surface;
A plurality of microwave radiation sources that are disposed around the reactor facing the main reflector and irradiate the sample mounting surface with microwaves;
The microwave heating apparatus, wherein the microwave radiation source is formed by disposing another microwave radiation source at a position shifted from a position facing the reactor through the reaction furnace.   A sub-reflecting mirror that is disposed at a position facing the main reflecting mirror and facing the microwave radiation source via the reaction furnace and that re-irradiates the sample mounting surface with the microwave reflected by the sample; The microwave heating apparatus according to claim 1, wherein The microwave radiation source is disposed on a circumference centered on the reactor,
The microwave heating device according to claim 2, wherein the sub-reflecting mirror is disposed between the microwave radiation sources on the circumference. The microwave radiation source is arranged at the apex of positive and odd squares with the reactor as a central part,
The microwave heating device according to claim 2, wherein the sub-reflecting mirror is disposed on a side between the vertices of the regular odd-odd square.   The microwave heating device according to any one of claims 2 to 4, wherein the sub-reflecting mirror is configured by a three-surface corner reflector.   6. The microwave heating according to any one of claims 2 to 5, wherein the microwave radiation source is configured by an active phased array antenna capable of adjusting the amplitude and phase of the radiated microwave. apparatus.   The microwave heating apparatus according to any one of claims 2 to 6, further comprising a heating unit provided outside the reaction furnace and heating the reaction furnace.

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