JP2009181727A - Microwave processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out heating treatment of heated objects with various shapes/kinds/volumes housed in a heating room at high efficiency and with heating unevenness suppressed. <P>SOLUTION: In a structure of generating microwaves at oscillating parts 1a to 1d and supplying the same from power-feeding parts 2a to 2d to a heating room 5, means for controlling oscillating power of the oscillating parts 1a to 1d and means for controlling radiation directions of the microwaves are combined against combinations of mutually interfering power-feeding parts (for instance, 2b and 2d) formed by intentionally varying excitation directions (for instance, 8a and 8d) of the microwaves in accordance with various shapes/kinds/volumes of heated objects 7 to perform optimum heating treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a microwave processing apparatus that generates a microwave with a magnetron and performs heat treatment.

  Conventionally, this type of microwave processing apparatus has a conventional technique in which a heating chamber is formed of six or more polyhedrons, and a radiating antenna is disposed so as to protrude from a part or all of each surface into the heating chamber (for example, Patent Document 1). Mutual interference can be prevented by arranging the radiating antennas on different surfaces, and since the radiating antennas are directed in different directions, the radiated radio waves propagate in all directions in the heating chamber and are reflected and scattered by the wall surface. Therefore, the radio waves are uniformly distributed in the heating chamber.

  The distribution unit includes a semiconductor oscillation unit, a distribution unit that divides the output of the oscillation unit into a plurality, a plurality of amplification units that amplify the distributed outputs, and a synthesis unit that synthesizes the outputs of the amplification units. There is a conventional technique in which a phase shifter is provided between the amplifier and the amplifier (see, for example, Patent Document 2). The power ratio of the two outputs can be changed by the phase shifter control, or the phase between the two outputs can be in phase or in phase.

Further, there is a conventional technique for detecting reflected power returning from the heating chamber in which the object to be heated is returned to the microwave generation unit and tracking the oscillation frequency at which the reflected power is minimized based on the reflected power signal. (For example, refer to Patent Document 3).
JP-A-52-19342 JP 56-132793 A JP-A-56-96486

  However, in the configuration of the conventional multiple power feeding method, as described below, it is difficult to heat-treat objects to be heated in various shapes, types, and quantities stored in a heating chamber to a desired state. Had.

  With regard to the arrangement of the radiating antennas, the space that can be used is limited due to the demand for expansion of the heating chamber capacity occupying the equipment volume, and it is practically difficult to install them on six surfaces. In addition, mutual interference cannot be reliably prevented only by disposing them on different surfaces.

  Since phase control works between microwaves that interfere with each other, it cannot be used in combination with multi-sided antenna arrangement or different frequency operation, and an effect under a wide range of conditions cannot be expected.

  The present invention solves the above-described conventional problems, and performs control of the excitation direction of the microwave radiated from the power supply unit to the heating chamber, and the control of the radiation power and the radiation direction performed in association with the control of the excitation direction. It aims at providing the microwave generation processing apparatus which heat-processes the to-be-heated object from which various shapes, types, and quantity differ in a desired state by optimizing each.

  In order to solve the above-described conventional problems, a microwave processing apparatus of the present invention includes a heating chamber that accommodates an object to be heated, an oscillation unit that generates microwaves, and a power feeding unit that supplies microwaves to the heating chamber. And a means for setting the excitation direction of the microwave radiated from the power feeding unit in an arbitrary direction. By controlling the excitation direction of the microwaves radiated from the power supply unit, the combination of the power supply units that cause mutual interference can be selected intentionally, and the excitation direction can be adjusted according to the object to be heated of various shapes, types, and quantities. The optimum heat treatment can be performed by combining the control of the radiation power and the radiation direction performed in association with the control.

  The microwave processing apparatus of the present invention performs a combination of the control of the excitation direction of the radiating microwave and the control of the radiation power, the radiation direction and the like performed in association with the control of the excitation direction, and has various shapes, types, and quantities. Different objects to be heated can be heated to a desired state.

  1st invention is equipped with the heating chamber which accommodates to-be-heated material, the oscillation part which generate | occur | produces a microwave, and the electric power feeding part which supplies a microwave to a heating chamber, The electric field or magnetic field of the microwave radiated | emitted from a power feeding part By having a means to set the direction (hereinafter referred to as the excitation direction) in any direction, it is possible to select the heat treatment in the excitation direction suitable for the object to be heated stored in the heating chamber. It can be heat-treated in a desired state according to each type of object to be heated.

  When a plurality of power feeding units are provided, by controlling the excitation direction of the radiating microwave, it is possible to intentionally select a combination of power feeding units that cause mutual interference and a combination of power feeding units that do not cause mutual interference.

  According to the second aspect of the invention, in particular, the electromagnetic of the intentional combination of the power feeding parts by the microwave is performed by performing the control using the mutual interference of the microwaves with respect to the combination of the power feeding parts having substantially the same excitation direction of the first invention. A field distribution can be formed, and a heated object having various shapes, types, and amounts can be heat-treated in a desired state.

  According to a third aspect of the present invention, in particular, for the combination of the feeding units that suppress the mutual interference of the microwaves by changing the excitation direction of the first aspect or the second aspect, independent control is performed. There is little influence on each optimum condition, and the expected result can be obtained.

  In the fourth aspect of the invention, in particular, with respect to two or more other power supply units having different excitation directions of the first aspect of the invention, the excitation direction is intentionally adjusted to an intermediate direction between each of the plurality of microwave radiations. By performing control using mutual interference, optimal heat treatment using means for changing the excitation direction can be performed with a smaller number of power supply units.

  The fifth aspect of the invention can be controlled particularly by the configuration in which the radiation direction can be intentionally controlled in combination with the excitation direction control of the microwave radiated from the power feeding unit of any one of the first to fourth aspects of the invention. Factors increase and finer heat treatment can be performed.

  The sixth aspect of the invention is a substantially flat metal surface facing the central conductor substantially in parallel with the feeding section that protrudes the central conductor through the heating chamber wall surface of any one of the first to fifth aspects of the invention. The excitation direction adjusting plate is provided, and the main excitation direction of the microwave radiated from between the central conductor and the excitation direction adjusting plate is made uniform, thereby realizing means for controlling the excitation direction of the microwave power supplied to the heating chamber.

  In the seventh invention, in particular, the excitation direction adjusting plate of the sixth invention is integrated with a portion substantially parallel to the wall surface of the heating chamber, so that electric field concentration on the heating wall surface can be alleviated, and the excitation direction adjusting plate is connected to the ground potential. The excitation electric field strength with the central conductor can be increased, and the surroundings can be rotated freely while being substantially parallel to the central conductor, and the main excitation direction generated between the central conductor and the excitation direction adjusting plate can be changed. Thus, the excitation electric field of the radiation microwave can be easily controlled.

  The eighth aspect of the invention can easily control the excitation electric field of the radiated microwave by including means for detecting the rotation position of the excitation direction adjusting plate of the sixth or seventh aspect and means for controlling the rotation angle.

  According to a ninth aspect of the invention, in particular, control of the excitation direction of the microwave radiated from at least one power supply unit of any one of the first to eighth aspects of the invention, and the radiated power and radiation performed in association with the control of the excitation direction, The direction control is switched according to the progress of cooking and load conditions, or changed during cooking, so that it can be heat-treated to the desired state in more detail according to each heated object of various shapes, types, and quantities. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a configuration diagram of a microwave processing apparatus according to the first embodiment of the present invention.

  In FIG. 1, the microwave generation unit is inserted into an oscillation unit 1 a to 1 d configured using a magnetron, a power feeding unit 2 a to 2 d that radiates a microwave output into the heating chamber, and a microwave transmission path to the power feeding unit 2 a to 2 d. The power detectors 3a to 3d that detect the power reflected from the power feeding units 2a to 2d, and the controller 4 that controls the oscillation of the oscillators 1a to 1d according to the reflected power detected by the power detectors 3a to 3d. It is composed.

  In addition, the microwave processing apparatus of the present invention has a heating chamber 5 having a substantially rectangular parallelepiped structure that accommodates an object to be heated, and the heating chamber 5 has a left wall surface, a right wall surface, a bottom wall surface, an upper wall surface, and an inner wall made of a metal material. An open / close door (not shown) that opens and closes to store the wall surface and the object to be heated, and a mounting table on which the object to be heated is placed, are configured to confine the supplied microwave inside. . And the electric power feeding parts 2a-2d which radiate | emit a microwave in the heating chamber 5 are arrange | positioned at the left, right, upper and bottom wall surfaces which comprise the heating chamber 5. FIG. The arrangement of the power feeding units is not limited to the present embodiment, and a plurality of power feeding units may be provided on any wall surface.

  By means of rotation control units 6a and 6d comprising means for detecting the rotational position (not shown) and means for controlling the rotation angle (not shown), the power feeding units 2a and 2d are made to be microwave electric fields or magnetic fields. The direction, that is, the excitation direction, can be adjusted and set to an arbitrary direction.

  And the microwave transmission path which connects each functional block should just be a propagation means corresponding to supply electric power, such as a waveguide and a coaxial line.

  In the above description, the rotation control units 6a and 6d, the means for detecting the rotation position, and the means for controlling the rotation angle correspond to the excitation direction setting means described in the claims.

  The power detection units 3a to 3d extract so-called reflected wave power transmitted from the heating chamber 5 side to the microwave generation unit side. The power coupling degree is, for example, about 40 dB, and the reflected power is about 1 Extract power of / 10000. Each power signal is rectified by a detection diode (not shown), smoothed by a capacitor (not shown), and the output signal is input to the control unit 4.

  Based on the heating information obtained from the heating condition of the object to be heated during the heating process and the detection information from the power detectors 3a to 3d, the control unit 4 is a micro The oscillators 1a to 1d, which are components of the wave generator, are controlled to optimally heat the object to be heated stored in the heating chamber 5.

  The operation of the microwave processing apparatus configured as described above will be described below.

  First, the object to be heated 7 is stored in the heating chamber 5, the heat treatment conditions are input from an operation unit (not shown), and the heating start key is pressed. Upon receiving the heating start signal, the control unit 4 operates a drive power supply (not shown) in response to the control output signal, supplies power to the oscillation units 1a to 1d, and oscillation starts. The generated microwave power is output to the power feeding units 2 a to 2 d via the power detection units 3 a to 3 d and radiated into the heating chamber 5. At this time, the respective power feeding units 2 a to 2 d generate excitation electric fields 8 a to 8 d to radiate microwaves into the heating chamber 5.

  The power detection units 3a to 3d detect the reflected power returning to the microwave generation unit, and detect a signal proportional to the amount of reflected power. The control unit 4 that receives the detection signal receives the reflected power. Select the operating condition for the minimum value.

  The present invention controls the excitation direction of the radiated microwave and the radiation power and the radiation direction in association with the excitation direction control, and controls various shapes, types and amounts of objects to be heated as desired. Although there is an effect of heat treatment in a state, in order to perform heat treatment in a desired state, “highly efficient heating performance” and “heating performance with less unevenness” are mainly required. The two performances will be described below.

  When the microwave power generated in the oscillation units 1a to 1d is efficiently radiated into the heating chamber 5 and absorbed 100% by the object to be heated, the reflected power from the heating chamber 5 side becomes 0 W. Reflection due to mismatch between the impedance of the heating chamber 5 including the heated object determined by the type, shape, and quantity of the heated object and the output impedance of the power feeding units 2a to 2d coupled to the heating chamber 5, and absorption by the heated object 7 Instead, the microwave power picked up by the power feeding units 2a to 2d returns to the generation unit side as reflected power. In the following, the operation of suppressing the reflected power to obtain a highly efficient heating performance will be described.

  In the heating chamber 5, microwaves are radiated from the plurality of power feeding units 2 a to 2 d, and microwaves in various excitation directions, electric powers, and propagation directions are disturbed, but in individual fields in the heating chamber 5, An electromagnetic field distribution in the heating chamber is formed by mutual interference that overlaps if the same electric field direction overlaps and cancels if the same electric field direction is opposite. The strength of the electric field in each field is related to the radiation power and radiation direction. Further, the direction of the electric field is deeply related to the excitation direction in the power feeding units 2a to 2d, and the combination and the degree of the microwaves that interfere with each other are also determined by this electric field direction.

  The rotation control unit 6d adjusts the direction of the excitation electric field 8d of the power supply unit 2d, and adjusts the radiated power and the radiation direction with respect to the combination with the power supply unit 2b in which the excitation electric fields are substantially matched, thereby adjusting the electromagnetic field distribution. Can be changed directly. By manipulating the electromagnetic field distribution in this way, it is possible to concentrate the electromagnetic field distribution on the object 7 to be heated and increase the microwave absorption efficiency.

  Further, another combination with mutual interference can be formed by adjusting the direction of the excitation electric field 8a of the power feeding unit 2a by the rotation control unit 6a and combining it with the excitation electric field 8c of the power feeding unit 2c. Since the feeding units 2a and 2c are different in the excitation direction from the combination of the feeding units 2b and 2d, the mutual interference relationship is not disturbed. If the electromagnetic field distribution formed by the power feeding units 2a and 2c is supplemented to the electromagnetic field distribution by the power feeding units 2b and 2d, the microwave absorption efficiency of the object to be heated 7 can be further increased. It becomes.

  In addition, the antenna has characteristics of a direction in which radio waves are easily radiated and received (directivity) and a direction of an electric field / magnetic field (excitation direction). Once these characteristics are matched, the antenna is once radiated into the heating chamber 5 to be heated. It becomes easy to pick up the microwave power which is not absorbed by 7. This phenomenon works in the same way for microwaves radiated from other power supply units. In the case of FIG. 1, the excitation directions of 8b and 8d coincide with each other, and mutual radiated radio waves are transmitted between combinations having mutual interference. It is easy to receive. When the electromagnetic field distribution is not controlled by mutual interference, the amount of microwave power received by matching the excitation directions can be reduced by changing the direction of the excitation electric field 8d of the power feeding unit 2d by the rotation control unit 6d. Contributes to the heating performance.

  As described above, even for objects to be heated having various shapes, sizes, and amounts, based on the reflected power detected by the power detection units 3a to 3d, the excitation directions of the microwaves radiated by the power feeding units 2a to 2d, and By controlling the radiation power determined in association with the excitation direction control and the radiation direction, a condition that the reflected power is minimized can be found and heat-treated, and “highly efficient heating performance” can be obtained.

  The microwave radiated to the heating chamber 5 in the limited closed space is absorbed by the object 7 to be heated, picked up by the power feeding units 2a to 2d, or repeatedly reflected on the wall surface of the heating chamber 5, thereby causing electromagnetic waves due to mutual interference. Although the field distribution is formed, the electromagnetic field distribution causes the intensity of heating in each field. The effect | action which suppresses heating nonuniformity is demonstrated below.

  The electromagnetic field distribution in the heating chamber 5 can be manipulated by controlling the excitation direction 8a to 8d of the microwaves radiated from the power feeding units 2a to 2d and the radiation power and the radiation direction in association with the control of the excitation direction. It is also possible to adjust uniformly. Furthermore, the group of the power feeding units 2b and 2d and the group of the power feeding units 2a and 2c having different excitation directions are operated at the same time in the electromagnetic field distribution formed by the power feeding units 2a and 2c. If the electromagnetic field distribution due to is complemented, a more uniform heating pattern can be formed.

  In actual cooking, a uniform electromagnetic field distribution does not always give an optimal result, and when the object to be heated is large, the surroundings are more likely to accumulate heat than the center where heat diffusion is good, resulting in uneven temperature. Similarly, thawing tends to facilitate the surrounding heating. For this reason, according to the cooking conditions of the selected object to be heated, the excitation direction, the radiation power performed in association with the control of the excitation direction, and the control of the radiation direction were intentionally strengthened in the central electromagnetic field distribution. As a result, a good finish can be obtained by cooking.

  Even if the electromagnetic field distribution unevenness is small, if the same pattern heating is continued, uneven heating due to heat storage occurs. Furthermore, since the object to be heated itself is not homogeneous, a deviation in the amount of heat generation also occurs. Therefore, the direction of the excitation electric fields 8a and 8d of the power feeding units 2a and 2d can be changed by the rotation control units 6a and 6d in the middle of cooking, so that the electromagnetic field distribution can be changed and uneven heating can be reduced.

  In this way, the control of the excitation directions 8a to 8d of the microwaves radiated from the power feeding units 2a to 2d and the radiated power and the control of the radiating direction associated with the control of the excitation direction are simply made uniform. By controlling the optimal electromagnetic field distribution that is not intended, it is possible to heat the object to be heated in various shapes, sizes, and quantities under conditions that minimize the uneven heating. Heating performance "can be obtained.

  FIG. 2 is an explanatory diagram of power supply means capable of moving the power supply portion.

  In FIG. 2, the power feeding unit 2 b includes an antenna vertical unit 9 and an antenna horizontal unit 10. The excitation electric field 8 b is generated between the wall surface of the heating chamber 5 and the antenna horizontal portion 10, and the microwave is radiated in the radiation direction 11. The power feeding unit 2b can rotate around the antenna vertical unit 9 and emit microwaves in an arbitrary direction of 360 ° in the horizontal direction. However, the generated excitation electric field 8b is always in the vertical direction and cannot be intentionally controlled.

  FIG. 3 is an explanatory diagram of an embodiment of the power feeding means of the present invention.

  In FIG. 3, the power feeding unit 2 d is configured by a central conductor 12 and an excitation direction adjusting plate 13 that can rotate around the central conductor 12 while being substantially parallel to the central conductor 12. The microwave power is supplied through the central conductor 12, but the excitation direction adjusting plate 13 aligns the excitation direction 8d between them in the vertical direction with the excitation direction adjusting plate 15 as shown in FIG. 4B. . When the excitation direction adjusting plate 15 rotates, the excitation direction 8d aligned with the vertical direction of the excitation direction adjusting plate 15 also rotates and the direction can be intentionally controlled.

  The heating chamber 5 side of the excitation direction adjusting plate 13 is integrated with an adjusting plate flat plate portion 14 substantially parallel to the wall surface of the heating chamber 5 as shown in FIG. Further, an insulating plate 15 is provided between the heating chamber 5 and the adjusting plate flat plate portion 14 and is rotatably held while being substantially parallel to the electrical insulation. The adjusting plate flat plate portion 14 prevents the electric field from concentrating with the wall surface of the heating chamber 5, and can be disposed in the vicinity. The electric potential of the integrated excitation direction adjusting plate 13 is brought close to the ground and is generated between the central conductor 12. The excitation electric field 8d is made as large as possible.

  The configuration of the power feeding unit is not limited to the present embodiment, and may have a function of adjusting the excitation direction to the intended direction.

(Embodiment 2)
FIG. 4 is a front explanatory view of another embodiment in which three power feeding portions 2 d to 2 f are provided on one wall surface of the heating chamber 5.

  4, 2d is configured to vary the excitation electric field 8d as in FIG. 1, and 2e and 2f are configured to supply fixed excitation electric fields 8e and 8f from the waveguide through the feeding ports 16e and 16f. .

  The excitation electric fields 8e and 8f have components in the depth direction (D) and the width direction (W) and have little mutual interference. The direction of the excitation electric field 8d is set in the middle of the excitation electric fields 8e and 8f, has both depth direction (D) and width direction (W) components, and affects both the excitation electric fields 8e and 8f. When the intermediate excitation direction is set in this way, the electromagnetic field distribution due to a plurality of different excitation electric fields can be simultaneously controlled from one power supply.

(Embodiment 3)
FIG. 5 is a side view of another embodiment of the power feeding means of the present invention.

  In FIG. The excitation electric field 8d ′ is generated between the left ends of both the central conductor 12 and the excitation direction adjusting plate 13 ′, and the microwave radiation direction 11d ′ is radiated in a direction perpendicular to the excitation electric field 8d ′. Therefore, the radiation direction changes as shown in FIG. 4C and FIG. 5 depending on the positional relationship between the center conductor 12 and the excitation direction adjusting plate 13 in the left direction. In the case of FIG. 4C, the excitation direction 8d can be intentionally controlled by rotating the excitation direction adjusting plate 13, but the microwave radiation direction 11d is hardly changed. With the configuration of FIG. 5, the excitation direction 8d ′ and the microwave radiation direction 11d ′ can be intentionally controlled by the rotation of the excitation direction adjusting plate 13 ′. Thereby, the factor of electromagnetic field distribution control in the heating chamber 5 can be increased, and more intended control can be performed.

  As described above, the microwave processing apparatus according to the present invention has a plurality of power feeding units, and controls switching of power feeding units that radiate microwaves or changes the direction of microwave excitation between the power feeding units in operation. Since the apparatus can be provided, the present invention can be applied to applications such as a heat treatment apparatus and a garbage processing machine using dielectric heating as typified by a microwave oven, or a microwave power supply of a plasma power supply which is a semiconductor manufacturing apparatus.

Configuration diagram of microwave processing apparatus according to Embodiment 1 of the present invention (A) Perspective view of microwave feed section of the present invention (b) Side view of microwave feed section of the present invention (A) Perspective view of microwave feed section in embodiment 1 of the present invention (b) Top view explanatory diagram of the microwave feed section in embodiment 1 of the present invention (c) Microwave in embodiment 1 of the present invention Side view of power feeding unit Front explanatory drawing of the microwave processing apparatus in Embodiment 2 of this invention Side surface explanatory drawing of the microwave electric power feeding part in Embodiment 3 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1d Oscillation part 2a-2f Feed part 3a-3d Power detection part 4 Control part 5 Heating chamber 6a, 6d Rotation control part 7 Heated object 8a-8f Excitation electric field 9 Antenna vertical part 10 Antenna horizontal part 11b, 11d Microwave Radiation direction 12 Center conductor 13 Excitation direction adjustment plate 14 Adjustment plate flat plate portion 15 Insulation plate 16e to 16f Feed port

Claims (9)

A heating chamber that accommodates an object to be heated, an oscillation unit that generates microwaves, and a power supply unit that supplies microwaves to the heating chamber, and an excitation direction of microwaves radiated from the power supply unit in an arbitrary direction A microwave processing apparatus having means for setting. Provided with a plurality of power supply units, provided with means for changing the excitation direction of the microwave radiated from the power supply unit in at least one of the power supply units, for the combination of the power supply units in which the excitation direction is adjusted to substantially the same direction, The microwave processing apparatus according to claim 1, wherein an arbitrary electromagnetic field distribution is formed in the heating chamber by detecting mutual interference of microwaves. A plurality of power supply units are provided, and at least one of the power supply units includes means for changing the excitation direction of the microwaves radiated from the power supply unit, each of the combinations of the power supply units adjusted in different directions of excitation, The microwave processing apparatus according to claim 1 or 2, wherein an independent electromagnetic field distribution is formed in the heating chamber by performing independent control. A plurality of power supply units are provided, and at least one of the power supply units is provided with means for changing the excitation direction of the microwaves radiated from the power supply unit. The microwave processing apparatus according to claim 1, wherein the excitation direction is changed to a direction, a mutual interference with the microwave radiation is detected, and an arbitrary electromagnetic field distribution is formed in the heating chamber. The microwave processing apparatus according to any one of claims 1 to 4, wherein an arbitrary electromagnetic field distribution is formed in the heating chamber by adjusting an excitation direction and a radiation direction of the microwave radiated from the power feeding unit. In a power feeding unit that penetrates the wall surface of the heating chamber and projects a rod-shaped center conductor toward the inside of the heating chamber and supplies microwaves to the heating chamber on the basis of the coaxial principle, it faces substantially parallel to the center conductor. The substantially flat metal excitation direction adjusting plate is provided, and the main excitation directions of the microwaves radiated from between the central conductor and the excitation direction adjusting plate are aligned. Microwave processing device. The excitation direction adjusting plate is integrally formed with a substantially parallel portion separated and adjacent to the wall surface of the heating chamber, and is rotatably installed around the center conductor while maintaining substantially parallel to the center conductor. The microwave processing apparatus according to claim 6, wherein a main excitation direction generated between the adjusting plates can be changed. The microwave processing apparatus according to claim 6 or 7, comprising means for detecting the rotational position of the excitation direction adjusting plate and means for controlling the rotational angle. The control of the excitation direction of the microwave radiated from at least one power supply unit and the radiation power and the control of the radiation direction performed in association with the control of the excitation direction are switched depending on the progress of cooking and load conditions, or changed during the cooking. The microwave processing apparatus according to any one of claims 1 to 8, wherein the microwave processing apparatus is provided.