JP2004063312A - High-frequency heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-use apparatus allowing a large effective volume of a heating chamber to be formed, in an apparatus provided with heating electrodes for sandwiching and heating a heating object. <P>SOLUTION: This high-frequency heating apparatus is provided with: the heating chamber 10 for storing the heating object; the heating electrode 18 disposed so as to interpose the heating object with at least one of them movable; and an electromagnetic wave leakage prevention means 33 installed on a wall surface 34 of the heating chamber facing to the movable heating electrode. Since spark generation between the heat chamber wall surface and the heating electrode can be restrained and the heating electrode can be moved and fixed to the vicinity of the heating chamber wall surface in executing microwave hating, the effective volume of the heating chamber can be increased, and the microwave heating can efficiently be executed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-frequency heating device in which dielectric heating and microwave heating can be used in combination with an object to be heated sandwiched between electrodes.
[0002]
[Prior art]
2. Description of the Related Art A microwave oven, which is a typical example of a high-frequency heating device, has become an indispensable device in daily life because it can directly heat an object to be heated, so that it is not necessary to prepare a pot. Further, the feature of the heating of the microwave oven is that heating energy can be supplied to the inside of the food, and the frozen food has been distributed in large quantities by utilizing this feature for thawing the frozen food.
[0003]
2. Description of the Related Art In a microwave oven, a heating chamber for storing an object to be heated generally has a size of about 30 to 40 cm in width and depth, and about 20 cm in height. On the other hand, the wavelength of the frequency used is about 12 cm, a strong and weak electric field distribution always occurs in the heating chamber, and the local heating may occur due to the synergistic effect of the shape of the object to be heated and its physical characteristics. is there. In the thawing of frozen foods, the heating energy is concentrated in the area where the ice has melted and turned into water, so that a local heating phenomenon appears remarkably, and there is a problem that partially boiled and unthawed coexist.
[0004]
A method of dielectrically heating an object to be heated by using a heating electrode by using a high frequency having a long wavelength has a long history, and even now, a batch system or a belt conveyor system is used for industrial use. These are large-sized apparatus configurations for processing large-sized frozen products and large-scale processing of frozen products, and the operation of the apparatus is also performed by skilled personnel.
[0005]
On the other hand, the application of the device using the heating electrode to a home device has been studied for a long time, but the value of convenience in life or convenience in use has not yet been provided to the user. As a conventional technique for providing practical value as a household device, there is, for example, Japanese Patent Application Laid-Open No. 9-92455. This publication proposes a configuration in which an electric connection part by electric wiring in a heating chamber is eliminated in consideration of the combined use with a microwave oven.
[0006]
[Problems to be solved by the invention]
The practical value of a household device is comparable to that of a microwave oven even if it is large in shape, and the main problem to be solved is to increase the effective volume of the heating chamber and secure usability similarly to a microwave oven.
[0007]
Regarding the compactness of the shape, the main issues are downsizing of the high-frequency generating means and downsizing of various impedance matching elements for matching the impedance between the heating electrode and the high-frequency generating means. Further, regarding the usability of the heating chamber, it is necessary to devise a method of housing the heating electrode.
[0008]
Japanese Patent Application Laid-Open No. Hei 9-92455 discloses that the upper electrode of a heating electrode moves up and down, and the movable upper electrode is moved to the uppermost part of a heating chamber during microwave heating. However, when the upper electrode, which is a conductor, is close to the wall of the heating chamber, there is a danger that the electrode or the wall of the heating chamber may be damaged due to the occurrence of sparks due to local concentration of the microwave electric field.
[0009]
The present invention solves the above-mentioned problems, and devises an arrangement of the movable heating electrode when not in use, increases the effective volume of the heating chamber during microwave heating, and heats the electrode during dielectric heating using the electrode. It is an object of the present invention to provide a device for efficiently heating an object to be heated by efficiently supplying a high frequency to an electrode for use.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, a high-frequency heating device according to the present invention includes a heating chamber that stores an object to be heated, a heating electrode in which at least one of the heating electrodes is arranged to sandwich the object to be heated, and a heating electrode that is movable. Radio wave leakage suppressing means provided on the wall surface of the heating chamber facing the electrodes is provided.
[0011]
According to the above invention, when performing microwave heating by moving and fixing the heating electrode near the heating chamber wall surface, transmission of microwaves in the gap between the heating chamber wall surface and the heating electrode can be suppressed, and spark generation can occur. Therefore, by disposing the heating electrode close to the wall surface of the heating chamber, the effective volume of the heating chamber can be increased and microwave heating can be performed efficiently.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 is a heating chamber for accommodating an object to be heated, a heating electrode in which at least one of the heating chambers is arranged so as to sandwich the object to be heated, and a heating electrode which is movable among wall surfaces of the heating chamber. An electrode provided on a surface facing the electrode and a radio wave leakage suppressing means for suppressing radio wave leakage from a gap between the heating chamber and the movable electrode, whereby the heating electrode is moved and fixed near the wall of the heating chamber. When microwave heating is performed, microwave transmission in the gap between the heating chamber wall surface and the heating electrode can be suppressed, and spark generation can be reliably suppressed, so the heating electrode is placed close to the heating chamber wall surface. By doing so, the effective volume of the heating chamber can be increased, and microwave heating can be performed efficiently.
[0013]
According to a second aspect of the present invention, in particular, the radio wave leakage suppressing means according to the first aspect is provided on a wall surface of a heating chamber opposed to a peripheral portion of a movable heating electrode. Since the propagation of the microwave to the central portion can be suppressed, an electric component or the like can be arranged at the central portion, and the movable heating electrode can be a high-pressure side electrode.
[0014]
The invention according to claim 3 is a method according to claim 1, wherein the high-frequency heating device according to claim 1 forms a predetermined clearance between a movable heating electrode and a wall surface of a heating chamber provided with a radio wave leakage suppression unit. A locking portion for fixing and supporting the movable heating electrode is provided, whereby the action of the radio wave leakage suppressing means can be reliably performed.
[0015]
According to a fourth aspect of the present invention, in particular, the high-frequency heating apparatus according to the second aspect is configured such that the wall of the heating chamber facing the movable heating electrode is formed in a comb shape, whereby the heating chamber is randomly formed. The action of the radio wave leakage suppressing means can be reliably applied to microwaves that propagate and enter the gap between the heating chamber wall surface and the heating electrode from all directions.
[0016]
The invention according to claim 5 includes a heating chamber for accommodating an object to be heated, and a heating electrode arranged so as to sandwich the object to be heated, wherein one of the electrodes is a wall surface of the heating chamber, On the wall surface of the chamber, a plurality of L-shaped microwave radiating ports arranged point-symmetrically with respect to a point on the tube axis of the waveguide at the end side of the waveguide for transmitting microwaves are provided in the heating chamber. By arranging a plurality of L-shaped radiation ports in a point-symmetrical manner, the directions of the electric fields that excite the radiation ports are different from each other. The radiated high frequency waves are combined or repelled in the vicinity of the radiation port to form a wide radiation distribution around the radiation port. By the behavior in the vicinity of the radiation port, the influence on the microwave generating means due to the difference in the amount and shape of the object to be heated is reduced, and the microwave generating means can be operated stably for various objects to be heated. The utilization efficiency of microwave energy can be improved. Furthermore, dielectric heating using an electrode and microwave heating using a microwave can be continuously performed.
[0017]
In the invention according to claim 6, in particular, the maximum spacing of the plurality of microwave radiating ports according to claim 5 in the tube axis direction of the waveguide is substantially equal to the transmission wavelength of the microwave transmitted through the waveguide. The length is set to ２, whereby the direction of the high-frequency electric field crossing each radiation port can be defined in the opposite direction, and the omnidirectional radiation direction can be ensured.
[0018]
According to a seventh aspect of the present invention, in particular, the plurality of microwave radiating ports according to the fifth aspect are configured so as not to cross the waveguide axis of the waveguide, and are thereby located on the microwave generating means side. The radiation energy from the radiation ports can be suppressed, and the microwave excitation of each radiation port can be guaranteed.
[0019]
In the invention according to claim 8, the high-frequency heating device according to claim 5 is preferably arranged such that the non-metallic material mounting portion on which the object to be heated is mounted, the microwave radiating port, and the mounting portion described above. Microwave stirring means which is rotatably supported on the microwave stirring means, wherein the microwave stirring means is supported by a non-metallic material having a low dielectric loss and a low magnetic permeability. Insulation can be ensured, and the uniformity of the electric field distribution between the electrodes during dielectric heating using the electrodes can be ensured.
[0020]
According to a ninth aspect of the present invention, in particular, the microwave stirring means according to the eighth aspect is a rectangular plate, thereby periodically chopping the microwaves radiated from the plurality of radiation ports. As a result, the uniformity of microwave heating can be promoted without moving the object to be heated.
[0021]
According to a tenth aspect of the present invention, in particular, the microwave stirring means according to the eighth aspect is a circular plate, and a plurality of L-shaped openings having a point of symmetry about the center of rotation are provided on the circular plate. This makes it possible to increase the effect on the microwaves radiated from the plurality of radiating ports, so that the microwaves are stirred more complicatedly, so that the uniformity of the microwave heating can be improved without moving the object to be heated. It can be further promoted.
[0022]
According to the eleventh aspect of the present invention, in particular, the L-shaped opening according to the tenth aspect is configured to have the same shape as the microwave radiating port provided in the waveguide. By emitting secondary rotating electric field from the means, uniform heating can be performed without moving the object to be heated.
[0023]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
(Example 1)
FIG. 1 is a front cross-sectional configuration diagram of a high-frequency heating apparatus according to a first embodiment of the present invention, FIG. 2 is a front cross-sectional configuration diagram when a heating electrode is moved in FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along the line AA ′ of FIG. 1, FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG. 1, and FIG. 7 is a circuit configuration diagram of FIG.
[0025]
1 and 2, reference numeral 10 denotes a heating chamber for storing an object to be heated, and a bottom surface 11 of the heating chamber 10 also serves as a heating electrode. On the bottom surface 11 of the heating chamber, there is provided a microwave radiating section 13 for supplying the microwave (2450 MHz band) generated by the microwave generating means 12 into the heating chamber 10. Reference numeral 14 denotes a waveguide for transmitting microwaves to the microwave radiating unit 13. The configuration around the microwave radiating section 13 will be described later. Reference numeral 15 denotes a microwave stirring means having a plate-like structure made of a metal material (a non-magnetic metal material, for example, aluminum), which is rotated by a motor 16. A mounting portion 17 made of a non-metallic material (for example, heat-resistant glass, ceramics, or heat-resistant resin) on which the object to be heated is placed so as to cover the microwave stirring means 15 is arranged. By using a non-metallic material for the mounting portion of the object to be heated, a sense of security can be provided, and since the object to be heated is insulated from the heating electrode 11, local heating of the object to be heated can be prevented.
[0026]
On the other hand, reference numeral 18 denotes another heating electrode (a non-magnetic metal material, for example, aluminum or SUS304), which is supported by arms 19 and 20 made of an insulating material (PPS or PS). The other ends of the arms 19 and 20 are fixedly connected to racks 21 and 22, respectively. Reference numeral 23 denotes a motor. A pinion 24 made of a resin material is arranged on an output shaft of the motor. By driving the motor 23, a rack meshed with a gear of the pinion 24 moves in the left-right direction in FIG. The motor 23 is a synchronous motor whose rotation direction is not restricted. Incidentally, the motor 23 may use a stepping motor.
[0027]
25 is a high-frequency generating means for generating a high frequency (for example, 13.56 MHz, 27.12 MHz) supplied between the bottom surface 11 of the heating chamber and the heating electrode 18, and 26 is an output power provided on the output side of the high-frequency generating means 25. And a power detector (such as a CM type SWR circuit) for detecting reflected power, and 27 is a power supply line. The power supply line 27 is formed of a coaxial cable, and the outer conductor 27a is connected to the wall surface 11 of the heating chamber 10 so as to be electrically conductive. The central conductor 27b of the power supply line 27 formed of a coaxial cable is connected to a coil 28 having a tap switching terminal, which is a variable impedance element.
[0028]
The other end of the coil 28 with the tap switching terminal, which is a variable impedance element, and one end of the fixed impedance element 29 are connected by a flexible plate-shaped conductor 30 having an insulator attached to the surface.
[0029]
The fixed impedance element 29 has a coil configuration and is formed by winding a conductive wire several times around a body 31 made of an insulating material fixed to the heating electrode 18. The other end of the fixed impedance element 29 is connected to the heating electrode 18. The body 31 is fixedly assembled to the heating electrode 18. With this configuration, the heating electrode 18 and the fixed impedance element 29 have an integral structure, and the fixed impedance element 29 is integrally formed with the movement of the heating electrode 18. Go up and down.
[0030]
Further, according to this configuration, the fixed impedance element 29 and the variable impedance element 28 are arranged in series between the high-frequency generator 25 and the heating electrode 18. Further, a fixed impedance element 32 arranged in parallel between the variable impedance element 28 and the high frequency generation means 25 is provided.
[0031]
This fixed impedance element 32 is a capacitor. FIG. 3 shows the detailed configuration of this capacitor. In FIG. 3, reference numerals 321 and 322 denote one electrode, 323 denotes the other electrode, and 324 and 325 denote a dielectric (a material having a high relative permittivity, for example, alumina) laminated between the electrodes.
[0032]
In addition, each electrode and the dielectric are provided with a hole having a predetermined size in the center, and after laminating them in order, a metal is inserted into the hole in the center to make the electrodes 321 and 322 conductive. Constructs a capacitor. The holes 326 and 327 provided on the electrodes 321 and 322 are holes for connecting one electrode, and the holes 328 provided on the electrode 323 are holes for connecting the other electrode. In FIGS. 1 and 2, a metal screw passed through the center is assembled with a metal surface that is electrically connected to the bottom surface 11 of the heating chamber.
[0033]
Next, the radio wave leakage suppressing means 33 will be described with reference to FIGS.
FIG. 4 is a sectional view taken along the line AA ′ of FIG. On the upper wall surface 34 of the heating chamber 10 facing the peripheral edge of the movable heating electrode 18, a comb-shaped region is arranged substantially periodically and circulated to form a comb-shaped region. A choke wall surface 36 that covers the comb region and forms a choke groove with the comb portion 35 is provided on the side of the comb region opposite to the heating electrode 18. Also, as shown in FIG. 1, the locking portions 37 and 38 for fixing and supporting the heating electrode 18 with a predetermined gap formed between the comb-shaped region and the choke wall surface 36 are formed by the wall surfaces. The radio wave leakage suppressing means 33 includes a heating electrode 18, a comb-shaped region in which the comb portions 35 are periodically arranged, a choke wall surface 36, and a locking portion. The length of the comb section 35 is about １ ／ wavelength (about 30 mm) of the wavelength of the microwave used, and the size of the gap 35 a provided between the comb sections is 10 mm. The width of the comb portion 35 is 20 mm in the straight portion and 10 mm in the corner portion.
[0034]
In FIG. 4, reference numeral 18a denotes the periphery of the heating electrode 18, reference numeral 39 denotes an opening / closing door for taking the object to be heated into and out of the heating chamber 10, and reference numeral 40 denotes an operation panel on which operation keys for inputting a heating operation of the apparatus are arranged.
[0035]
By the radio wave leakage suppressing means 33 configured as described above, the impedance when the comb side is viewed from the surrounding position of the heating electrode 18 has a very low value. As a result, the metal wall surface for confining the microwave in the heating chamber 10 acts like a metal body in which the upper wall surface 34 of the heating chamber 10 and the heating electrode 18 are continuous. Therefore, the generation of sparks between the heating electrode 18 and the wall surface of the heating chamber can be suppressed.
[0036]
In addition, this action suppresses the inflow of microwaves into the heating electrode 18 on the side opposite to the heating chamber 10, so that the fixed impedance element 29 can be arranged at the center of the heating electrode 18, and the variable impedance element 28 can be disposed. A power line 41 or the like connecting the fixed impedance element 29 and the like can be arranged, and the heating electrode that can move as in the present embodiment can be a high-voltage side electrode.
[0037]
Further, when performing microwave heating, by fixing the heating electrode close to the wall surface of the heating chamber without danger of spark, the effective volume of the heating chamber can be increased and the microwave heating can be performed efficiently.
[0038]
In addition, since the locking portion is provided, a predetermined gap can be reliably formed, and the action of the radio wave leakage suppressing means can be reliably operated. Further, the comb-like configuration ensures that the action of the radio wave leakage suppressing means can be reliably applied to microwaves that propagate randomly in the heating chamber and enter the gap between the heating chamber wall surface and the heating electrode from all directions.
[0039]
Next, the surroundings of the microwave radiating section 13 will be described with reference to FIGS. The microwave radiating portion 13 has a waveguide end face 42 on the side of the waveguide 14 remote from the side where the microwave generating means is mounted, and approximately １ ／ of the transmission wavelength of the frequency transmitting the waveguide 14 from this end face 42. (The H-plane of the waveguide) between them. The microwave radiating portion 13 is constituted by L-shaped openings 13a and 13b, respectively, and is arranged point-symmetrically. The point-symmetric position is on the tube axis 43 of the waveguide 14 and is the center of the hole 44 in the figure. Each of the openings 13a and 13b of the microwave radiating portion 13 has a portion parallel to and perpendicular to the tube axis of the waveguide 14, and the openings are arranged so as not to cross the tube axis.
[0040]
Also, reference numeral 45 shows an example in which the transmission wavelength in the waveguide is a standing wave distribution, but it is not necessary to limit the length of the waveguide 14 to resonate in the waveguide as shown.
[0041]
The hole 44 is penetrated by the output shaft (made of non-metal and low dielectric loss material) of the motor 16 which is connected to the microwave stirring means 15 and rotates it. The microwave stirring means 15 has a rectangular plate configuration made of a metal material as described above, and its plate surface is arranged substantially parallel to the bottom surface 11 of the heating chamber. With such a configuration, the microwave stirring means 15 is arranged so as to be insulated from the wall surface 11 of the heating chamber 10. The configuration of the microwave stirring means 15 minimizes the non-uniform distribution of the high-frequency electric field generated between the heating electrodes in the heating using the electrodes. Reference numeral 46 denotes a hole into which the output antenna of the microwave generating means 12 is inserted and assembled.
[0042]
Next, the main operation of the microwave radiating section will be described. The microwave transmitted through the waveguide 14 causes a high-frequency current as shown by arrows 47 to 50 in FIG. 6 to flow on the waveguide wall surface, and similarly causes arrows 47 to 50 to flow through the L-shaped radiation ports 13a and 13b. A high-frequency electric field in the direction indicated by. The high-frequency electric fields are mutually coupled to form a rotating electric field and radiate from the radiation port. This forms a wide radiation distribution around the radiation outlet. The behavior in the vicinity of the radiation port reduces the influence on the microwave generation means due to the difference in the amount and shape of the object to be heated, and enables the microwave generation means to operate stably with respect to the object to be heated in various ranges. As a result, the utilization efficiency of the generated microwave energy can be increased.
[0043]
The microwave radiated from the microwave radiating section 13 into the heating chamber 10 while generating a rotating electric field is disturbed by the microwave stirring means 15, and the microwave is radiated all over the heating chamber 10, and the microwave is radiated. Promotes uniform heating of heated objects. The microwave stirring means 15 is, for example, a rectangular plate having a width of 20 mm and a length of 120 mm (preferably 90 mm or more).
[0044]
FIG. 7 shows a circuit diagram relating to heating using the electrodes of the above-described apparatus. In FIG. 7, 25 is a high-frequency generating means, 26 is a power detector, 32 is a fixed impedance element arranged in parallel, 28 is a variable impedance element arranged in series consisting of a variable coil with tap switching, and 29 is a fixed impedance element arranged in series. , 18 are movable heating electrodes, 11 is a bottom surface of the heating chamber, 17 is a mounting portion, and 51 is an object to be heated.
[0045]
Next, the movable operation of the heating electrode 18 will be described.
When the motor 23 is operated in the state shown in FIG. 1, the rotation direction of the motor 23 is regulated in a direction in which the racks 21 and 22 can move freely, whereby the motor 23 rotates in a direction in which the heating electrode 18 moves down. The lowering of the heating electrode 18 continues as shown in FIG. 2 until the arms 19 and 20 become substantially vertical. In this state, one ends of the racks 21 and 22 hit the wall surfaces 52 and 53 of the heating chamber. Then, the driving torque of the motor 23 in the current rotation direction increases, and the motor 23 starts rotating in the opposite direction to eliminate the increase. Thereby, the heating electrode 18 starts to rise and returns to the uppermost position as shown in FIG.
[0046]
In the uppermost position shown in FIG. 1, the heating electrode 18 is restricted from rising by metal parts 37 and 38 which are one of the components of the radio wave leakage suppressing means 33. The arrival of this position is detected by a limit switch (not shown), and the operation of the motor 23 is stopped.
[0047]
A method of controlling the heating electrode 18 when the object to be heated is stored will be described below with respect to the elevating operation of the heating electrode 18. When the motor 23 is operated after the object to be heated is mounted, the heating electrode 18 starts to descend, and when the heating electrode 18 comes into contact with the object to be heated or the container for the object to be heated, the descending operation stops. At this time, a driving torque is generated in the motor 23, and the driving current of the motor increases accordingly. The driving current is monitored, and after detecting an increase in the driving current, the operation of the motor is stopped after a predetermined time has elapsed, so that the heating electrode 18 is stopped and fixed in the heating chamber 10.
[0048]
Thereafter, the high-frequency generator 25 is operated, and based on the detection signal of the power detector 26, the tap switching position of the variable impedance element 28 is selected so that the reflected power is minimized. In this way, the high-frequency heating is continued, and the heating is stopped for a predetermined time or based on a temporal change of the reflected power.
[0049]
Next, the effectiveness of high-frequency heating using the electrode having the above configuration will be described with reference to FIG. FIG. 8 shows a point P1 in FIG. 7 when the gap between the heating electrode 18 and the object to be heated is set to 10 mm and the value of the variable impedance element is selected such that the reflected power is minimized. Is a plot of the impedance value, as viewed from the side of the heating electrode side, on the Smith chart. The measurement frequency is 13.56 MHz, the fixed impedance element 32 arranged in parallel is a 690 pF capacitor, the fixed impedance element 29 in series is a 2 μH coil, and the variable impedance element 28 is 0.7 μH, 0.8 μH, 0.9 μH. Using. The shape of the heating electrode 18 is 250 mm x 200 mm, and the objects to be heated are 100 g, 300 g of beef sliced meat (marked with □ in the figure), minced meat (marked with △ in the figure), and tuna block (marked with ● in the figure). 500 g were used.
[0050]
A broken line circle 54 in the figure indicates that the value of the voltage standing wave ratio is 2, which is about 11% in terms of power reflectance. Although impedance matching adjustment is performed only by selecting the value of the variable impedance element 28 for the object to be used, the reflected power can be made sufficiently small, and the output power of the high-frequency generator 25 can be efficiently applied to the object to be heated. It was confirmed that the material could be supplied well, and the object to be heated could be well thawed in a short time.
[0051]
That is, it is possible to realize a sufficiently practical high-frequency heating device by using only one variable impedance element. In this case, in the two impedance elements (fixed impedance element and variable impedance element) arranged in series, the impedance value of the fixed impedance element provided on the heating electrode side is twice or more the maximum impedance value of the variable impedance element. Thereby, a high voltage is divided between the heating electrodes and the two impedance elements arranged in series. Since the fixed impedance element shares a high voltage, the connection between the fixed impedance element and the heating electrode is basically thick and short, and the fixed impedance element is integrally assembled with the heating electrode. Thereby, heat generation of the connection portion can be suppressed.
[0052]
In addition, since the high voltage is concentrated on the heating electrode and the fixed impedance element, heat generation at the connection between the fixed impedance element and the variable impedance element can be suppressed, and a highly flexible conductive wire can be used for this connection. .
[0053]
The larger the ratio of the impedance value is, the more effective it is. However, in consideration of securing the variable range of the variable impedance, it can be practically used up to about 4 to 5 times.
[0054]
From the above, each impedance element involved in impedance matching is optimized by optimizing the impedance ratio of each impedance element arranged in series using fixed impedance elements arranged in parallel and fixed impedance elements arranged in series as well as variable impedance elements arranged in series. It is possible to realize an apparatus that can be configured compactly and that can realize adjustment of impedance matching with simple control.
[0055]
In FIG. 6, although the tube axis of the waveguide and the microwave radiating portion are arranged on the bottom surface of the heating chamber, the same effect can be obtained even if these are arranged on the side surface.
[0056]
(Example 2)
Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment differs from the first embodiment in the configuration of the microwave stirring means. Note that the same members or the same equivalent members as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0057]
That is, in FIG. 9, radiation ports 13 a and 13 b having an L-shaped opening are arranged at the end side of the rectangular waveguide 14 so that the point located on the tube axis of the waveguide 14 is point-symmetric. ing. Above the plurality of radiation ports 13a and 13b, there is provided a microwave stirring means 55 made of a substantially circular metal plate as a rotating body. The microwave stirring means 55 is configured to be rotationally driven around the point symmetric position 44 of the plurality of radiation ports 13a and 13b as the center of rotation. That is, a support (not shown) made of a non-metallic material having a low dielectric loss and a low magnetic permeability is provided at the center of the substantially circular shape of the microwave stirring means 55, and the output shaft of the motor 16 is fitted to the support. Have been combined. The microwave stirring means 55 has openings 56a and 56b similar to the L-shaped openings provided in the waveguide 14.
[0058]
With such a configuration, the L-shaped openings 56a and 56b provided in the microwave stirring means 55 are protected by rotating the microwave stirring means 55 while protecting the radiation distribution formed by the L-shaped radiation ports. By acting as a second radiation port and radiating microwaves to the object to be heated, uniform heating of the object to be heated can be promoted without moving the object to be heated.
[0059]
The shape of the opening provided in the microwave stirring means 55 is not limited to the L-shape. For example, a plurality of rectangular shapes may be arranged so that the longitudinal directions thereof are orthogonal to each other. Further, the microwave stirring means 55 may be driven to rotate eccentrically. Further, the microwave stirring means 55 may have any configuration as long as it allows a radiation distribution appearing through a radiation port having an L-shaped opening provided in the waveguide 14, and may have a fan shape, for example.
[0060]
In the above embodiments, it is desirable that the corners of the radiation ports or openings are appropriately rounded from the viewpoint of processing and suppression of spark generation due to edge portions.
[0061]
【The invention's effect】
As described above, according to the present invention, the movable electrode for heating is provided with the radio wave leakage suppressing means provided on the wall surface of the heating chamber facing the movable electrode, so that the heating electrode is moved and fixed near the wall of the heating chamber. When microwave heating is performed, the transmission of microwaves in the gap between the heating chamber wall surface and the heating electrode can be suppressed, and the generation of sparks can be reliably suppressed, so that the effective volume of the heating chamber can be increased and the microwave can be increased. Wave heating can be performed efficiently.
[0062]
Further, in the heating chamber for accommodating the object to be heated, one of the heating electrodes arranged so as to sandwich the object to be heated is used as the wall surface of the heating chamber, and the end of the waveguide for transmitting microwaves is provided with the waveguide. A wide radiation distribution is formed around the radiation port by arranging a plurality of L-shaped microwave radiation ports arranged point-symmetrically with respect to a point on the tube axis of the heating chamber at a substantially central portion of the wall surface of the heating chamber. In addition, the influence on the microwave generating means due to the difference in the amount and shape of the object to be heated is reduced, and the microwave generating means can be operated stably for various objects to be heated, and the utilization efficiency of the microwave energy is improved. be able to. Further, a highly convenient device capable of continuously performing dielectric heating using an electrode and microwave heating using a microwave can be provided.
[Brief description of the drawings]
FIG. 1 is a front cross-sectional view of a high-frequency heating device according to a first embodiment of the present invention; FIG. 2 is a front cross-sectional view when a heating electrode of the high-frequency heating device is moved; FIG. FIG. 4 is a sectional view taken along the line AA ′ of the high-frequency heating device. FIG. 5 is a sectional view taken along the line BB ′ of the high-frequency heating device. FIG. 6 is a microwave radiation of the high-frequency heating device. FIG. 7 is a circuit configuration diagram relating to heating using electrodes of the high-frequency heating device. FIG. 8 is a load impedance characteristic diagram of the high-frequency heating device for various objects to be heated. FIG. 9 is an embodiment of the present invention. Configuration diagram around the microwave radiating section of the high-frequency heating device 2 [Explanation of reference numerals]
10 heating chamber 11 bottom of heating chamber (one heating electrode)
12 Microwave generation means 13 Microwave radiation part (supply part)
13a, 13b, 56a, 56b L-shaped opening 15, 55 Microwave stirring means 17 Mounting part 18 Heating electrode (movable heating electrode)
25 High frequency generating means 33 Radio wave leakage suppressing means 35 Comb portions 37, 38 Locking portion 43 Waveguide tube shaft 51 Heated object

Claims (11)

A heating chamber for accommodating the object to be heated, a heating electrode movable at least one of which is arranged so as to sandwich the object to be heated, and a heating electrode provided on a surface of the wall surface of the heating chamber opposite to the movable heating electrode. A high-frequency heating apparatus comprising: a radio wave leakage suppressing unit that suppresses a radio wave from leaking from a gap between a chamber and the movable electrode. The high-frequency heating device according to claim 1, wherein the radio wave leakage suppressing means is provided on a wall surface of the heating chamber facing a peripheral portion of the movable heating electrode. 2. The high-frequency device according to claim 1, further comprising: a locking portion for fixedly supporting the movable heating electrode with a predetermined clearance formed between the movable heating electrode and a wall of the heating chamber provided with the radio wave leakage suppressing means. Heating equipment. 3. The high-frequency heating apparatus according to claim 2, wherein a wall surface of the heating chamber facing the movable heating electrode has a comb shape. A heating chamber for storing the object to be heated, and a heating electrode arranged so as to sandwich the object to be heated, one of the electrodes being a wall surface of the heating chamber, and a microwave being transmitted to the wall surface of the heating chamber. A plurality of L-shaped microwave radiating ports arranged point-symmetrically with respect to a point on the tube axis of the waveguide on the terminal side of the waveguide to be arranged are arranged at substantially the center of the wall surface of the heating chamber. High-frequency heating device configured. The high-frequency heating apparatus according to claim 5, wherein the maximum interval between the plurality of microwave radiating ports in the direction of the tube axis of the waveguide is substantially half the transmission wavelength of the microwave transmitted through the waveguide. The high-frequency heating device according to claim 5, wherein the plurality of microwave radiation ports are configured not to cross the axis of the waveguide. A mounting portion of a non-metallic material for mounting an object to be heated, a microwave stirring means rotatably supported between the microwave radiating port and the mounting portion, and the microwave stirring means is made of non-metal. The high-frequency heating apparatus according to claim 5, wherein the apparatus is supported by a material having low dielectric loss and low magnetic permeability. The high-frequency heating device according to claim 8, wherein the microwave stirring means is a rectangular plate. 9. The high-frequency heating apparatus according to claim 8, wherein the microwave stirring means is a circular plate, and the disk has a plurality of L-shaped openings having a point of symmetry about the center of rotation. The high-frequency heating apparatus according to claim 10, wherein the L-shaped opening has a shape equivalent to a microwave radiation port provided in the waveguide.

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