JP6533783B2 - Microwave irradiation device - Google Patents

Description

  The present invention relates to a microwave irradiation apparatus having a cavity provided with a plurality of magnetrons.

  It is known that microwaves have chemical reaction promoting effects different from those of conventional heating methods, and such effects are called microwave effects, microwave electric field effects, or non-thermal effects. The field of application of microwaves is wide, such as organic chemistry, inorganic chemistry, ceramics, medicine, etc. For example, as organic chemistry reaction, production of polyester resin or production of copper phthalocyanine is known.

  The microwave irradiation mode through the microwave transmitting material includes air irradiation method and in-liquid irradiation method. From the viewpoint of heating efficiency, the in-liquid irradiation method in which the microwave is directly irradiated to the object to be heated is better It is said that Further, in the in-liquid irradiation method, since microwaves are directly irradiated to the object to be heated, there is an advantageous effect of preventing high-power microwave energy from directly acting on metal parts such as thermocouples and stirring shafts. There is a case. When the microwaves enter the dielectric, they are transformed into heat and the strength is sharply reduced, so that the action on the metal parts in the liquid is extremely limited. For example, in the case of water at 25 ° C., it is known that the depth to which the power density of the microwave, which is said to be the power half depth, is reduced to half is only 1.3 cm.

  The applicant has disclosed in Patent Document 1 a tubular container having an irradiation unit made of a microwave transmitting material to which microwaves from a waveguide are irradiated, and a partition plate disposed at a predetermined interval on a stirring shaft, And / or a partition member configured by partition plates disposed at predetermined intervals on the inner wall of the tubular container, the partition member partitioning the tubular container at predetermined intervals, and the flow of one or more objects to be heated located between the partition members The apparatus has an agitation blade generating mixing in a direction opposite to the direction, and comprises an agitation shaft axially passing through the tubular container, and a microwave heating means, and the object to be heated flowing in the tubular container is the agitation blade We proposed a microwave irradiator for microwave heating with stirring.

  In Patent Document 2, there is provided a heating chamber for heating a film roll which is provided with a reflecting plate of microwaves on its inner surface and which is wound into a roll shape with a film laminated and adhered, and is installed outside the heating chamber. A film roll heating apparatus comprising: a microwave oscillator that oscillates and irradiates the heating chamber with microwaves; and a stirrer fan installed on the heating chamber ceiling and stirring the microwaves. It is done.

Patent No. 5016984 gazette Unexamined-Japanese-Patent No. 2012-214000

In the microwave heating of a solid, when heating a relatively large object, when heated by one high-power oscillator, there is a problem that the temperature unevenness due to the partial contact of the microwave increases. On the other hand, when heating is performed by a plurality of low-power oscillators, there is a problem that the heat uniformity is improved but the heating efficiency is reduced due to the interference of microwaves.
There is a need for a cavity-type microwave irradiation apparatus in which the interference of microwaves in multiple irradiations is taken into consideration, and the problem of the decrease in heating efficiency due to the interference being eliminated.

  Therefore, an object of the present invention is to provide a cavity type microwave irradiation apparatus in which the problem of the decrease in heating efficiency due to interference is eliminated.

  The inventors have made it possible to suppress microwave interference and ensure high heat uniformity by irradiating microwaves from multiple directions not facing each other and using a rotary reflector. In addition, by suppressing the interference, high heating efficiency is ensured even in the case of multiple irradiation. Furthermore, it is possible to prevent discharge when the microwave absorption of the object to be heated is small.

A supplementary explanation of microwave interference is given.
When microwaves are irradiated from two waveguides facing each other to heat the object to be heated, the heating efficiency is improved when mutually strengthening each other, but there is a problem that the efficiency is reduced when they are mutually weakened. In the case of a general-purpose magnetron, since there is a wide range of oscillation frequencies, it is very difficult to control interference with the highest efficiency, and the efficiency may be significantly reduced. Furthermore, if the size and position of the heating object to be put in are different, the electromagnetic field distribution will also be different, but it is not realistic to set control conditions in consideration of interference for each heating object. Therefore, the inventor has made various improvements for the purpose of obtaining a heating efficiency that is directly proportional to the number of oscillators (magnetrons) by minimizing the interference, and has made it possible to minimize the microwave interference. . Specifically, the following improvements were made.

(1) Irradiating microwaves from directions not facing each other.
(2) Diffuse microwaves on a rotary reflector and reflect them randomly.
(3) A more random reflection by providing a holed structure for the rotary reflector and providing a notch in the reflector.
(4) Do not use a stepping motor as the motor used for rotation, for example, use a synchronous motor or an induction motor, for example, so that even if interference occurs, it does not last.

That is, the present invention comprises the following technical means.
The microwave irradiator according to the present invention comprises: a plurality of irradiators each having an irradiance port for irradiating a microwave from a magnetron; a cavity provided with the plurality of irradiators; and a door for opening and closing one surface of the cavity. A microwave irradiation device comprising a control unit, wherein the plurality of irradiation units are provided on inner wall surfaces other than the surface on which the door of the cavity is provided so as not to face each other; The apparatus is characterized in that the unit includes a reflecting plate, and the microwaves emitted from the magnetron are indirectly irradiated into the cavity through the reflecting plate.
In the above-mentioned microwave irradiation apparatus, the irradiation unit does not have a waveguide including a reflecting plate, a recess in which the reflecting plate is accommodated, a plate covering the recess, and an irradiation port provided on the inner side surface of the recess. The irradiation portion may be characterized, in which case the irradiation openings of the plurality of irradiation portions are preferably arranged not to face each other, and the space in the cavity is It is more preferable that it is a cube shape or rectangular solid shape, and the said irradiation part consists of three irradiation parts.

The microwave irradiation apparatus including the three irradiation units includes a radiation type temperature sensor capable of measuring the temperature of the object to be irradiated, and the control unit is configured to calculate the third value based on a detection value of the radiation type temperature sensor. The present invention may be characterized in that the output of the microwaves emitted from the individual irradiation units may be controlled, and in this case, an optical fiber temperature sensor, and a storage container for the irradiation object to which the optical fiber temperature sensor can be inserted. Preferably, the control unit controls the output of the microwaves irradiated from the three irradiation units based on the detection values of the optical fiber type temperature sensor and the radiation type temperature sensor. It is more preferable to be characterized in that a plurality of the radiation type temperature sensors are provided, and the control unit is based on the detection values of one or more radiation type temperature sensors from one or more irradiation units. It is further preferably characterized in that it comprises a plurality of control systems for controlling the output of the microwave Isa.
In the microwave irradiation apparatus including the radiation type temperature sensor, the radiation type temperature sensor may be disposed on a plurality of inner wall surfaces of the cavity.
In the microwave irradiator including the radiation-type temperature sensor, the radiation-type temperature sensor may include a plurality of the radiation-type temperature sensors arranged in an array.
In the microwave irradiation apparatus provided with the above-mentioned radiation type temperature sensor, the radiation type temperature sensor is provided on the upper part or the side part of the cavity, and further, the object to be irradiated is arranged at the center or near the center of the cavity It is preferable that the table is provided with a table made of a microwave transparent material, and in this case, the table has an object to be irradiated at a height of 1/4 wavelength or more of the microwave from the bottom surface of the cavity. More preferably, it is characterized in that it can be arranged.
In the above-mentioned microwave irradiator, the reflecting plate may be provided with a plurality of reflecting vanes, and may further be provided with a rotating device for rotating the reflecting plate. In this case, the reflecting plate has a side view. It is preferable to be characterized by having a frusto-conical shape, and it is more preferable to be characterized by that the reflective blade is composed of 3 to 10 reflective blades having a perforated structure.
In the above-mentioned microwave irradiation apparatus, the irradiation unit may include a chamber in which an inner surface excluding the irradiation port is covered with a metal plate, and the magnetron may be installed in the chamber.
The microwave irradiation apparatus described above may be a tabletop type.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the microwave irradiation apparatus which has a cavity by which the problem of the fall of the heating efficiency by interference was eliminated.

It is a perspective view of the microwave irradiation device concerning an example of an embodiment. It is a transmission perspective view showing a cavity of a microwave irradiation device concerning an example of an embodiment. It is a perspective view showing the structure of the irradiation mouth and the roof concerning the example of an embodiment. It is an explanatory view of indirect irradiation of the microwave concerning an example of an embodiment. It is a top view of a reflective board concerning an example of an embodiment. It is a perspective view of a reflective board concerning an example of an embodiment. It is a thermal image which concerns on Experimental example 1, (a) is a thermal image of one-directional irradiation, (b) is a thermal image of three-directional irradiation. (A) shows a thermal image when irradiated in three directions without using a reflector, (b) shows a thermal image when irradiated in three directions without rotating a reflector, (a) c) is a thermal image when irradiating in three directions while rotating the reflector. It is a measurement result of the network analyzer which concerns on Experimental example 3, (a) is a measurement result at the time of irradiating without using a reflection board, (b) is a measurement result at the time of irradiating using a rotating reflection board. (A) is a block diagram of the apparatus of the comparative example 1, (b) is a block diagram of the apparatus of experiment example 4. FIG. (A) is a device simulation result of Comparative Example 1, (b) is a device simulation result of Experimental Example 4. (A) is an apparatus simulation result of Experimental example 5-1, (b) is an apparatus simulation result of Experimental example 5-2. It is a block diagram of the system of Experimental example 6. FIG. It is a perspective view of the stand concerning experimental example 6. FIG. It is a temperature measurement result and the output of a microwave which concern on Experimental example 6, (a) is a result of controlling based on the measurement temperature of a radiation type temperature sensor, (b) is a result controlled based on a measurement temperature of an optical fiber type temperature sensor It is. It is a block diagram of the system of Experimental example 7. FIG.

A microwave irradiator according to a preferred embodiment of the present invention will be described.
FIG. 1 is a perspective view of a microwave irradiation apparatus 1 according to an embodiment. The microwave irradiation apparatus 1 according to the embodiment has a table-top microwave irradiation including a cavity 3 provided inside a rectangular parallelepiped casing 2, a door 4 that slides open and close up and down, and an operation unit 5. It is an apparatus.

The cavity 3 is a rectangular space having a square bottom surface of 550 mm and a height of 400 mm, and can irradiate a 300 mm square object to be irradiated with microwaves. On three surfaces of the inner wall of the cavity 3, irradiation units 7a to 7c having magnetrons 6a to 6c are respectively disposed. The surface on which the irradiation units 7a to 7c are disposed is not limited to the illustrated position, and among the six surfaces constituting the inner wall of the cavity 3, the surface may be disposed on any of the five surfaces except the surface provided with the door 4 Good. However, from the viewpoint of uniform heating, it is preferable that the irradiation units 7 a to 7 c be disposed substantially at the center of the inner wall surface of the cavity 3. Each of the magnetrons 6a to 6c is of the same specification with a frequency of 2.45 GHz and an output of 1 kW. That is, according to the microwave irradiation apparatus 1 of the example of embodiment, it is possible to irradiate a microwave to the heating object of largest size 400x400x300 (mm) with the output of 3 kW.
The operation unit 5 is provided with operation buttons, and it is possible to select a preset irradiation pattern. On the back side of the operation unit 5, a processor and a storage device are provided, and a control unit (not shown) is disposed. The control unit controls the outputs of the magnetrons 6a to 6c based on a predetermined program stored in the storage device. By installing one or more temperature sensors capable of measuring the temperature of the object to be irradiated, and independently controlling the output of the microwaves emitted from the plurality of irradiation units based on the detection value of the temperature sensor You may comprise so that the temperature of a heating target can be controlled.

  The irradiation units 7a to 7c are frame-shaped frames 71a to 71c, concave portions 72a to 72c, irradiation openings 73a to 73c which are openings provided on the inner side surface of the concave portions, and a roof covering the upper portions of the irradiation openings 73a to 73c. Portions 74a to 74c, rotary shafts 75a to 75c to which the reflection plates 8a to 8c are attached, and plates 76a to 76c (not shown in FIG. 2) covering the concave portions 72a to 72c.

  The irradiation units 7a to 7c are disposed such that the rotation axes 75a to 75c are positioned at the centers of the wall surfaces as shown in FIG. 2 (note that the reflection plates 8a to 8c are not shown in FIG. 2). ). The irradiation units 7a to 7c are provided in directions that do not face each other so that the irradiation targets placed on the bottom can be efficiently irradiated with the microwaves. Specifically, the irradiation unit 7 a is provided on the back surface of the cavity 3, the irradiation unit 7 b is provided on the right side of the cavity 3, and the irradiation unit 7 c is provided on the bottom of the cavity 3. Although three irradiation parts 7a-7c are provided in embodiment example, when an output may fall, it can also be two. The important thing is to prevent each irradiation part from facing each other. Therefore, the upper limit of the number of magnetrons that can be installed is three when the shape of the cavity 3 is a hexahedron, four when it is an octahedron, and five when it is a decahedron. It becomes.

  More preferably, unlike in FIG. 2, the irradiation ports 73 a to 73 c are disposed so as not to face each other. Here, in order to arrange the irradiation ports so as not to face each other, it can be realized by not arranging the respective irradiation ports of the adjacent irradiation parts on the inner side surface farthest away from each other. For example, in FIG. 2, the irradiation port 73 b of the irradiation unit 7 b is provided on the opposite inner side (ie, 180 ° turn), and the irradiation opening 73 c of the irradiation unit 7 c is provided on the opposite inner side (ie, 180 ° turn) Is disclosed. However, even if the irradiation ports are arranged so as to face each other, the microwaves irradiated from the respective irradiation ports are blocked by the reflecting plate (without passing through the notch) and are not incident on the opposing irradiation ports If this is the case, the effect of interference is considered not to be a problem.

  As shown in FIGS. 3 and 4, the magnetron 6 is disposed at the back of the irradiation port 73. As described above, since the microwave irradiation apparatus 1 according to the embodiment has a structure without the waveguide, the size of the housing 2 can be compact (prototype shown in FIG. 1). The width of the housing 2 in the is about 82 cm, and the width including the operation unit 5 is about 98 cm. The upper portion of each irradiation port 73 is covered by a metal roof portion 74, and a chamber 77 whose surface excluding the irradiation port is a metal inner wall surface is provided inside the irradiation port 73, and the inside of each chamber is provided. And the magnetron 6 is installed. Thus, by providing the chamber 77 which covers the surroundings other than the irradiation surface (irradiation port) with a metal plate, direct reflection of the reflected wave is prevented from being absorbed, and the heating efficiency is improved (for example, 90% when the object to be irradiated is water) Or more). The roof portion 74 also has the effect of preventing microwaves from being irradiated directly into the cavity from above the magnetron 6 and causing uneven heating. In the embodiment, the chamber 77 is made of SUS.

The rotating shafts 75a to 75c are respectively connected to a rotating device (not shown) such as a motor, and can rotate the reflectors 8a to 8c at a desired speed.
Since the microwaves irradiated from the irradiation ports 73a to 73c are reflected by the rotating dish-like reflecting disks 8a to 8c and indirectly irradiated (randomly irradiated) to the space in the cavity, the problem of interference can be eliminated. Yes (see FIG. 4).

  Plates 76a to 76c are disposed in the irradiation sections 7a to 7c so as to be flush with the inner wall surface of the cavity 3. The material of the plates 76a to 76c is not particularly limited as long as it transmits microwaves and has a certain degree of heat resistance and strength, but may be made of, for example, quartz, alumina, Teflon (registered trademark), polypropylene, or neoceram. It is possible. When the irradiation unit 7 is not provided on the bottom surface of the cavity 3, it is possible to lower the required levels of heat resistance and strength required for the plates 76a to 76c.

As shown in FIG. 5, the reflectors 8a to 8c are composed of four reflecting blades 81 having a perforated structure and a disc-like truncated head 82. Although the number of reflective blades is not limited to four as illustrated, it is preferable that the number of reflective blades be three or more in order to realize random irradiation, and for example, three to ten reflective blades are used to form a dish The reflection plate 8 is configured. The holed structure of the reflective blade 81 is not limited to the illustrated shape, and may be a holed structure consisting of a large number of holes (for example, a punching metal having holes of a size capable of transmitting microwaves, a honeycomb structure, a lattice structure) Good. Each reflective blade is provided with a hole that occupies, for example, 20 to 70% of the area of the reflective blade.
Further, it is preferable to provide notches 83 of substantially the same size as the reflective blades between the reflective blades. The reflecting plate 8 is made of metal, and in the embodiment, it is made of SUS.

FIG. 6 is a perspective view of reflectors 8a to 8c according to the embodiment.
Reflectors 8a to 8c attached to rotary shafts 75a to 75c having a fixed length have a dish shape such that each reflective blade 81 is directed to the bottom surface of the concave portions 72a to 72c, and the side view truncated cone It is shaped (conical). In other words, by providing the reflective blade 81 attached so as to form an acute angle with the rotation shaft 75, the gap G between the bottom of the concave portions 72a to 72c and the tip of the reflective blade 81 is reduced. With such a configuration, the microwaves irradiated from the magnetrons 6a to 6c are prevented from passing through without hitting the reflecting blade 81, and the reflectance is enhanced. On the other hand, when the gap G between the bottoms of the concave portions 72a to 72c and the reflective blade 81 becomes too small, there is a problem that the discharge D is generated at the time of low load (when absorption of microwaves by the irradiated object is small) between them. There is. That is, the larger the gap G between the bottom surfaces of the concave portions 72a to 72c and the reflective blade 81, the lower the reflectance, while the smaller the gap G, the trade-off relationship is that the possibility of discharge increases. The extent to which the size of the gap G is set depends on the configuration of each device, but generally, it is disclosed to set the size of the gap G in the range of 5 to 20 mm.

  The microwave irradiation apparatus 1 is suitable for the use which carries out microwave heating of the solid of a fixed size or more. According to the microwave irradiation apparatus of the present invention, it is possible to heat an individual filled in a container (mold) having a bottom surface of 400 mm square. Conventionally, an apparatus for heating by near-infrared light has also been used, but the apparatus size is large and heavy (for example, several thousand Kg), and the price is also expensive. In this respect, the microwave irradiation apparatus of the present invention has a small apparatus size, can reduce the structural cost, and can process in a short time.

Experiment 1
In order to verify the thermal uniformity by three-direction irradiation, temperature rising experiments of a cardboard box (W 280 mm × W 280 mm × H 160 mm) were performed by the microwave irradiation device 1. In Experimental Example 1, microwaves were irradiated while rotating the reflecting plate 8, the temperature of the cardboard box was raised to 50 ° C. at 10 ° C./min, and the temperature was measured by a radiation type temperature sensor.
FIG. 7A is a thermal image of one-way irradiation, and FIG. 7B is a thermal image of three-direction irradiation. In (a), the difference between the maximum temperature and the minimum temperature (the temperature difference at the location shown by a triangle in the figure) was 40.9 ° C., whereas in (b) the difference between the maximum temperature and the minimum temperature Was 13.5 ° C. According to the experimental example 1, it is confirmed that the temperature unevenness due to one contact increases in the one-direction irradiation, but the uniform heating can be realized by the three-direction irradiation.

Experiment 2
In order to verify the stirring action of the reflecting plate 8, the same temperature rising experiment of the same cardboard box as the experimental example 1 was performed by the microwave irradiation apparatus 1. In Experimental Example 2, microwaves were irradiated under three conditions: reflector rotation, reflector rotation, and reflector absence, and the temperature of the cardboard box was raised to 50 ° C. at 10 ° C./min. Was measured.
8 (a) shows a thermal image in the case of three-directional irradiation without using a reflecting disk, FIG. 8 (b) shows a thermal image in the case of irradiating in three directions without rotating the reflecting disk 8, and FIG. It is a thermal image at the time of irradiating three directions, making it rotate. The difference between the maximum temperature and the minimum temperature is 31.7 ° C, the difference between the maximum temperature and the minimum temperature is 15.1 ° C, and the difference between the maximum temperature and the minimum temperature is 13 It was .5 ° C. It was confirmed that the degree of temperature unevenness was the smallest in (c) and the largest in (a).

Experiment 3
In order to verify the interference suppression effect by the reflecting plate 8, the inside of the cavity of the microwave irradiation apparatus 1 was measured by a network analyzer. In Experimental Example 3, a test probe was inserted from the left side of the cavity 3 and the incidence to the cavity was measured. FIG. 9 (a) shows the measurement result in the case of irradiation without using a reflection plate, and FIG. 9 (b) shows the measurement result in the case of irradiation using a rotating reflection plate. From these measurement results, it can be seen that the microwaves enter the cavity regardless of the presence or absence of the reflector.

A comparative experiment of heating efficiency was conducted using 5 L of water as an irradiation object. (1) The heating efficiency was 85% when irradiated in three directions (1 kW x 3) without using a reflector, but (2) 90% when heated in three directions using a rotating reflector. It became. (3) The heating efficiency in the case of one-direction irradiation (1 kW) without using a reflector and (4) the heating efficiency in the case of one-way irradiation (1 kW) using a rotating reflector were the same.
From the above experimental results, it was confirmed that the reflection efficiency does not affect the heating efficiency in the one-direction irradiation, but the heating efficiency is improved by the reflection efficiency in the three-direction irradiation. Therefore, it can be said that interference of microwaves in irradiation in a plurality of directions can be suppressed by using a rotating reflector.

Experiment 4
Arranged so that the two magnetrons do not face each other in the device of Comparative Example 1 in which two magnetrons are arranged facing each other in a model in which a virtual absorber is installed inside the device, and in the model where a virtual absorber is installed in an inside of the device The simulation was performed with the apparatus of Experimental Example 4 as described above. The configuration of the device of Comparative Example 1 is shown in FIG. 10 (a), and the configuration of the device of Experimental Example 4 is shown in FIG. 10 (b). For simulation, AET's CST STUDIO SUITE 2013 was used. The device simulation result of Comparative Example 1 is shown in FIG. 11 (a), and the device simulation result of Experimental Example 4 is shown in FIG. 11 (b).
When the S parameters were compared, the values of S1, 1 in the devices of Comparative Example 1 and Example 4 were low, while the values of S2, 1 were significantly higher in the device of Comparative Example 1 than in the device of Experimental Example 4. You can see that it is getting higher.
From the above, it was confirmed that when the magnetrons are disposed facing each other, one microwave affects the other microwave feeding surface.

Experiment 5
The device of Experimental Example 5-1 provided with a reflecting plate having two reflecting vanes and two opposed magnetrons, the device of Experimental Example 5 provided with a reflecting plate having eight reflecting vanes and two opposed magnetrons The simulation was carried out. For simulation, AET's CST STUDIO SUITE 2013 was used. The device simulation result of Experimental Example 5-1 is shown in FIG. 12 (a), and the device simulation result of Experimental Example 5-2 is shown in FIG. 12 (b).
When S parameter was compared, the apparatus of Experimental example 5-1 and Experimental example 5-2 showed the low value with both.
From the above, it has been confirmed that the reflection board having eight reflection vanes as well as the reflection board having two reflection vanes has an effect of preventing the interference of two opposing magnetrons.

Experimental Example 6
The system of Experimental Example 6 (1) arranges the irradiation object at a height at which the uniformity of the heating uniformity and the absorption efficiency can be balanced without inhibiting the irradiation of the microwave of the irradiation object, (2) the irradiation By directly or indirectly measuring the temperature of the object and controlling the output of the microwave, it is possible to control the heating of the object to be irradiated within the target temperature range.
As shown in FIG. 13, the system of Experimental Example 6 includes a microwave irradiation apparatus 1, a stand 9, a container 10, an optical fiber temperature sensor 11, and a radiation temperature sensor 16. The apparatus 1 of Experimental Example 6 also includes a housing 2, a cavity 3, a door 4, an operation unit 5, irradiation units 7a to 7c (not shown) having magnetrons 6a to 6c, and reflection disks 8a to 8c (not shown) However, since the configuration is the same as that of the experimental example 1, the description will be omitted. Each element will be described below.

  A container 10 installed on a platform 9 described later is a sealed container in which an object to be irradiated with microwaves is stored. The container 10 is made of a microwave transparent material (for example, glass or Teflon (registered trademark)), and the content is heated by absorbing the microwave. Unlike this, the container 10 is made of a microwave absorbing material (for example, a polymer or silicone rubber containing SiC or carbon), and the contents are uniformly heated by heat conduction from the container 10. It is also good.

The container 10 can be equipped with a vacuum tube 13 for enabling a reduced pressure. The vacuum tube 13 connected to the vacuum pump 15 via the pipe fitting 14 can be inserted into the container 10 to reduce the pressure in the container 10. In order to suppress discharge due to microwaves, the vacuum tube 13 is made of silicone rubber or the like, and the pipe joint 14 is made of a resin such as polypropylene.
As a modification of the system of Experimental Example 6, two pipe joints 14 may be provided, two vacuum tubes 13 may be inserted into the container 10, and the atmosphere of the container 10 may be replaced. In this modification, the atmosphere replacement and the pressure reduction of the container 10 can be switched depending on whether the number of vacuum tubes 13 inserted into the container 10 is two or one.

  The optical fiber type temperature sensor 11 is a contact type temperature sensor that measures the temperature of the contents of the container 10. A protective tube made of alumina or glass is put on the tip of the temperature sensor 11 of the optical fiber type temperature sensor 11, and the protective tube is inserted into the container 10. The optical fiber type temperature sensor 11 is connected to the light detector 12, and the outputs of the magnetrons 6a to 6c (not shown) are controlled based on the temperature measured by the light detector 12. The optical fiber type temperature sensor 11 is, for example, a fluorescence type sensor using a fluorescent substance in a temperature sensitive part, and a measurable temperature range is −20 to 400 ° C.

  The radiation type temperature sensor 16 is a noncontact temperature sensor that measures the surface temperature of the container 10. The radiation type temperature sensor 16 is used to monitor the surface temperature of the container 10 and to control the output of the magnetrons 6a to 6c (not shown). The radiation type temperature sensor 16 is, for example, a temperature sensor that measures the intensity of infrared light or visible light, and the measurable temperature range is −25 to 380 ° C. Unlike the illustration, a plurality of radiation type temperature sensors may be configured by planar sensors arranged in an array (for example, 8 × 8). When the radiation-type temperature sensors are arranged in an array, the temperature distribution of the object to be irradiated can be acquired, so that the outputs from the three directions (irradiation units 7a to 7c) can be dynamically changed based on the temperature distribution. It becomes possible. In order to form the planar sensor, it is preferable to arrange the number of radial temperature sensors in the longitudinal and lateral directions.

  The radiation type temperature sensor 16 is installed on the upper surface or the side surface of the cavity 3 of the microwave irradiation device 1. This is to prevent infrared light and visible light emitted from the container 10 from being blocked by the table 9. From the viewpoint of uniform heating and fail-safety, it is preferable to install a plurality of radiation type temperature sensors 16, and it is more preferable to install the radiation type temperature sensors 16 on a plurality of inner wall surfaces, It is further preferable to install the radiation type temperature sensor 16 on the The output control of microwaves using a plurality of radiation type temperature sensors 16 will be described later.

  The pedestal 9 is for disposing the container 10 at or near the center of the cavity 3 to increase the microwave absorption efficiency and to achieve uniform heating. The stand 9 is composed of a plurality of members which can be assembled, and when the size of the container 10 is changed, the mounting height can be adjusted. The table 9 is made of a microwave transparent material (for example, resin or glass such as polypropylene or Teflon (registered trademark)), and therefore, the table 9 does not inhibit the microwave irradiation to the container 10. As shown in FIG. 14, the platform 9 includes two legs 91, two beams 92, a top plate 93, and a rubber pad 94.

  The legs 91 support the beam 92 and adjust the height of the beam 92 depending on the number of steps to be assembled. The two legs 91 and the two beams 92 are assembled in the form of the symbol "#". That is, two legs 91 are spaced apart in parallel, and two beams 92 are assembled so as to bridge the two legs 91. The beam portion 92 is provided with a recess near its both ends, and the leg portion 91 is inserted into the recess and assembled. A leg for increasing height (not shown) can be attached to the bottom side of the leg 91. The leg portion 91 is provided with a cylindrical recess 91b on the bottom surface thereof, and can be assembled by inserting the protrusion provided on the upper surface of the leg portion for height increase. The holes 91a, 92a provided in the leg 91 and the beam 92 are for weight loss.

The top plate 93 is for supporting the container 10 placed on the table 9. The top plate 93 is provided with two parallel grooves 93a on its back surface, and the beam portion 92 is inserted into the grooves 93a and assembled.
For the leg portion 91, the beam portion 92, and the top plate 93, for example, polypropylene is used.
The rubber pad 94 is for preventing deformation or deterioration of the top plate 93 due to heat when the container 10 becomes high temperature. The rubber pads 94 are in a grid shape to suppress heat conduction, but the rubber pads 94 may not be provided under conditions where a high degree of uniform heating is required.

  The height of the table 9 is adjusted, for example, so that the container 10 is positioned at a position 1⁄4 to 1 wavelength away from the irradiation unit 7 located on the bottom of the cavity. At this time, it is necessary to take into consideration that the microwave absorption efficiency is reduced although the soaking property is improved because the microwaves are less likely to be hit locally as the container 10 is separated from the irradiation port. From another point of view, the height of the platform 9 is adjusted so that the container 10 is located at or near the center of the cavity.

By providing the table 9, in the microwave irradiation apparatus 1 provided with the radiation type temperature sensor 16, it becomes possible to realize uniform heating by three-direction irradiation. In order to realize uniform heating by three-way irradiation, it is important to dynamically change the output of microwave irradiation from each direction. In order to change the output of microwave irradiation from each direction dynamically, it is preferable to install a plurality of radiation type temperature sensors 16 on a plurality of surfaces, and more preferably to install radiation type temperature sensors 16 on 3 or more surfaces Do.
In order to measure the surface temperature of the container 10 placed on the table 9, it is necessary to set the radiation type temperature sensor 16 on the side surface or the upper surface of the unshielded cavity by the table 9, and When installed on the two side surfaces and the bottom surface of the above, the degree of freedom of installation of the plurality of radiation type temperature sensors 16 is increased.

The output control of microwaves according to the temperature of the object to be irradiated changes in the measurement temperature by the optical fiber type temperature sensor 11 and / or the radiation type temperature sensor 16 with respect to the magnetrons 6a to 6c (inclination of temperature rise / drop) It is disclosed to control to feed back (for example, PID control (Proportional-Integral-Derivative Controller)).
By providing a plurality of control systems (for example, a first system that controls the output from the bottom and a second system that controls the outputs from the two side surfaces) based on a plurality of temperature sensors in the control unit, Fine uniform heating is realized. The same number of temperature sensors as the irradiation ports may be provided on the same inner wall surface as the irradiation ports 73a to 73c, and microwave output may be independently controlled for each irradiation unit. When the object to be irradiated has a non-cube shape (for example, a thin shape), charring tends to occur unless the independent control is performed. The temperature sensor used for feedback control preferably uses a combination of an optical fiber type temperature sensor and a radiation type temperature sensor. However, as described below, the control precision of the optical fiber type temperature sensor is higher.

FIG. 15 shows the case where the container 10 is arranged near the center of the cavity 3 by the table 9 and the measurement temperature of the radiation type temperature sensor 16 is used as a microwave output control method (b) an optical fiber type temperature sensor It shows changes in measured temperature and microwave output when measured temperature is used. The solid line indicates the measured temperature or output, and the dotted line indicates the target temperature.
In both cases (a) and (b), the measured temperature of the temperature sensor used for control could be made to follow the target temperature, but in the control of the radiation type temperature sensor 16, the control of the optical fiber type temperature sensor 11 Also, the microwave output was not stable, and the temperature of the contents indicated by the optical fiber type sensor increased while the temperature was maintained. This indicates that the radiation type temperature sensor that measures the surface temperature is susceptible to heat radiation, and that temperature control considering heat radiation is necessary to keep the temperature of the contents constant.

From the above, it is possible to accurately control the temperature of the irradiated object (the content of the container 10) by using the optical fiber type temperature sensor 11 for direct control of the temperature of the content. Was confirmed.
If the optical fiber type temperature sensor 11 is used for temperature control of the contents, and the radiation type temperature sensor 16 is used as a monitor of the surface temperature of the container 10 by using the optical fiber type temperature sensor 11 and the radiation type temperature sensor 16 in combination, accurate temperature Abnormal heating and the like can be detected while performing control. In addition, since setting such as insertion into the container 10 is not necessary for the non-contact type radiation type temperature sensor 16, if accurate temperature control is not necessary, temperature control can be simplified simply using the radiation type temperature sensor 16 It can also be done.

  From the above experimental results, (1) a cavity having a balanced heating uniformity and absorption efficiency due to the configuration provided with the base 9 and the radiation type temperature sensor 16 and the radiation type temperature sensor 16 provided in the cavity 3 It becomes possible to arrange near the center of 3. In addition, an optical fiber type temperature sensor 11 is provided, and the output of the magnetron is controlled using the temperature measured by the radiation type temperature sensor 16 or the optical fiber type temperature sensor 11, (2) accurate temperature control of the object to be irradiated It has been confirmed that this is possible.

Experimental Example 7
The system of Experimental Example 7 is the system of Experimental Example 6 with the change of the configuration that enables the atmosphere substitution in the container 10 added, in order to insert the vacuum tube 13 for sucking and discharging the gas into the container 10 Differs from the system of Experimental Example 6 in that the shield pipe of
As shown in FIG. 16, the system of Experimental Example 7 includes a microwave irradiator 1, a stand 9, a container 10, an optical fiber temperature sensor 11, a radiation temperature sensor 16, and first and second shield pipes 17 and 18. Is equipped. The apparatus 1 of Experimental Example 7 also includes a housing 2, a cavity 3, a door 4, an operation unit 5, irradiation units 7a to 7c (not shown) having magnetrons 6a to 6c, and reflection disks 8a to 8c (not shown) However, since the configuration is the same as that of the experimental example 1, the description will be omitted. In addition, about the component same as Experimental example 6, description may be omitted by attaching | subjecting the same code | symbol.

  The first and second shield pipes 17 and 18 are provided in the casing 2 of the microwave irradiation apparatus 1 so as to communicate the cavity 3 with the outside. A vacuum tube 13 for suctioning air into the container 10 is inserted through the first shield pipe 17, and a vacuum tube 13 for exhausting air from the container 10 is inserted through the second shield pipe 18. The first and second shield pipes 17, 18 have a larger inner diameter than the vacuum tube 13, so a plurality of vacuum tubes 13 can be inserted. The first and second shield pipes 17 and 18 may be one shield pipe. In this case, both the intake and exhaust vacuum tubes 13 or the exhaust vacuum tube 13 is one shield pipe. It is inserted.

  Two vacuum tubes 13 for intake and exhaust are inserted into the container 10. In the case of atmosphere replacement, gas for replacement is externally supplied to the suction vacuum tube 13, and the gas in the container 10 is discharged from the vacuum tube 13 for exhaustion. When performing pressure reduction, do not use the vacuum tube 13 for suction, either provide a cock and close it midway, or close the vacuum tube with a pinch cock or the like to close it, and connect the vacuum pump 15 to the vacuum tube 13 for evacuation. The pressure inside the container 10 is reduced.

According to the system of Experimental Example 7, since the plurality of vacuum tubes 13 can be inserted into the first and second shield pipes 17 and 18, the plurality of containers 10 are set in the cavity 3. Atmosphere replacement or depressurization can be performed. Further, since the inside of the cavity 3 can be physically accessed from the outside of the microwave irradiation apparatus 1, it is possible to monitor the temperature and the appearance of the container 10 by inserting an optical fiber type temperature sensor or a fiberscope.
Also in the system of the experimental example 7, as in the system of the experimental example 6, (1) the object to be irradiated can be disposed near the center of the cavity 3 in which the heating uniformity and the absorption efficiency are well-balanced ) Accurate temperature control of the object to be irradiated is possible.

  As mentioned above, although the preferable embodiment of this invention was described, the technical scope of this invention is not limited to the description of the said embodiment. Various modifications and improvements can be added to the above-described embodiment, and modifications in which such modifications or improvements are added are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 microwave irradiation apparatus 2 case 3 cavity 4 door 5 operation part 6 magnetron 7 irradiation part 8 reflecting plate 9 base 10 container 11 optical fiber type temperature sensor 12 photodetector 13 vacuum tube 14 pipe joint 15 vacuum pump 16 radiation type temperature Sensor 17 Shield pipe 18 Shield pipe 71 Frame 72 Recess 73 Irradiation port 74 Roof 75 Rotation shaft 76 Plate 81 Reflective blade 82 Cut head 83 Notch 91 Leg 92 Beam 93 Top plate 94 Rubber pad

Claims (17)

A plurality of irradiation units having irradiation ports for irradiating microwaves from a magnetron;
A cavity provided with a plurality of irradiation units;
A door for opening and closing one side of the cavity;
A microwave irradiator including a controller;
The plurality of irradiation units are provided on inner wall surfaces other than the surface on which the door of the cavity is provided so as not to face each other.
The irradiator includes a chamber and a reflector, the inner surface of which is covered with a metal plate except for the irradiator, and microwaves emitted from the magnetron installed in the chamber enter the cavity through the reflector. A microwave irradiation apparatus characterized by being indirectly irradiated. A plurality of irradiation units having irradiation ports for irradiating microwaves from a magnetron;
A cavity provided with a plurality of irradiation units;
A door for opening and closing one side of the cavity;
A microwave irradiator including a controller;
The plurality of irradiation units are provided on inner wall surfaces other than the surface on which the door of the cavity is provided so as not to face each other.
The irradiation unit includes a reflecting plate and a recess in which the reflecting plate is accommodated, and microwaves emitted from the magnetron are indirectly irradiated into the cavity through the reflecting plate.
A microwave irradiator according to claim 1, wherein the irradiation ports of the plurality of irradiators are disposed so as not to face each other on the inner side surface of the recess. A plurality of irradiation units having irradiation ports for irradiating microwaves from a magnetron;
A cavity having a cubic or rectangular solid interior space provided with a plurality of irradiation parts;
A door for opening and closing one side of the cavity;
A microwave irradiator including a controller;
The plurality of irradiation units are provided on inner wall surfaces other than the surface on which the door of the cavity is provided so as not to face each other.
The irradiation unit comprises three irradiation units each provided with a reflecting disk, and the microwave irradiated from the magnetron is indirectly irradiated into the cavity through the reflecting disk. apparatus. The space in the cavity has a cubic or rectangular shape,
The microwave irradiator according to claim 1 or 2, wherein the irradiator comprises three irradiators. It has a radiant temperature sensor that can measure the temperature of the object to be irradiated,
The microwave irradiation apparatus according to any one of claims 1 to 4, wherein the control unit controls the output of the microwaves irradiated from the plurality of irradiation units based on the detection value of the radiation type temperature sensor. .   The microwave irradiator according to claim 5, further comprising an optical fiber type temperature sensor and a storage container for an object to be irradiated in which the optical fiber type temperature sensor can be inserted.   7. The microwave according to claim 6, wherein said control unit controls the output of microwaves irradiated from said three irradiation units based on detection values of said optical fiber type temperature sensor and said radiation type temperature sensor. Irradiation device. A plurality of the radiation type temperature sensors,
8. The micro-computer according to claim 7, wherein the control unit comprises a plurality of control systems for controlling the output of the microwaves emitted from the one or more irradiation units based on the detection value of the one or more radiation type temperature sensors. Wave irradiation device.   9. A microwave irradiator according to claim 8, wherein the radiation type temperature sensor is disposed on a plurality of inner wall surfaces of the cavity.   The microwave irradiation apparatus according to claim 8 or 9, wherein the radiation temperature sensor comprises a plurality of radiation temperature sensors arranged in an array. The radiation temperature sensor being provided at the top or the side of the cavity;
The microwave irradiator according to any one of claims 5 to 10, further comprising a table made of a microwave transparent material for arranging the object to be irradiated at or near the center of the cavity.   The microwave irradiation apparatus according to claim 11, wherein the pedestal is capable of arranging the object to be irradiated at a height of 1/4 wavelength or more of the microwave from the bottom surface of the cavity. The reflecting plate comprises a plurality of reflecting vanes,
The microwave irradiation device according to any one of claims 1 to 12, further comprising a pivoting device for pivoting the reflecting plate.   The microwave irradiator according to claim 13, wherein the reflector is frusto-conical in a side view, and reflects microwaves in a direction substantially orthogonal to the irradiation port.   The microwave irradiation device according to claim 13 or 14, wherein the reflecting blade is composed of 3 to 10 perforated reflecting blades.   The microwave irradiator according to any one of claims 2 to 15, wherein the irradiator comprises a chamber in which an inner surface excluding the irradiator is covered with a metal plate, and the magnetron is installed in the chamber.   The microwave irradiator according to any one of claims 1 to 16, wherein the irradiator is an irradiator without a waveguide and is a tabletop type.