JP3931623B2 - High frequency heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency heating apparatus that dielectrically heats an object to be heated, and more particularly to the configuration and radiation control of a high-frequency radiation unit in a heating chamber.
[0002]
[Prior art]
The high-frequency heating device is an indispensable device in daily life because it can directly heat an object to be heated and does not require preparation of a pan. However, since the heating chamber that houses the object to be heated is not a structure whose shape can be changed, the electrical characteristics of the heating chamber change depending on the presence of the object to be heated. This change in electrical characteristics in the heating chamber affects the characteristics of the high-frequency generating means that generates the high frequency supplied into the heating chamber and the high-frequency distribution in the heating chamber. The influence received by the high frequency generation means is represented by changes in the oscillation frequency and the oscillation output. In addition, the high-frequency distribution may cause local heating due to a synergistic effect of the shape of an object to be heated and its physical characteristics.
[0003]
The ideal characteristics of the high-frequency heating device are summarized in that the high-frequency energy generated by the high-frequency generating means is supplied to the object to be heated with maximum efficiency and the object to be heated is uniformly heated.
[0004]
From the viewpoint of high-efficiency utilization of high-frequency energy, the measurement method of the high-frequency output displayed on the high-frequency heating device is stipulated in the JIS standard and IEC standard, and the amount of the object to be heated used for high-frequency output measurement is 2000 cc of water. And 1000 cc, which is different from the amount of the object to be heated generally (about 200 cc to 400 cc) in daily life. Due to the influence of the amount of the object to be heated, the high-frequency output with respect to the general amount of the object to be heated has a utilization efficiency of about 60 to 80% of the output value displayed on the apparatus.
[0005]
As a technique for improving such a high frequency characteristic, a matching technique at a high frequency is used. In the first place, the high-frequency heating device maximizes the high-frequency energy generated by the high-frequency generating means for the object to be heated specified in the standard, and transmits the metal post into the waveguide to optimize the matching state. In general, it is designed. Of course, if the arrangement position and shape of the metal post are changed, an optimum alignment state can be achieved for any object to be heated. However, in order to move the metal post, a complicated and expensive structure is required. It has become a practical issue.
[0006]
It is also known that this matching metal post affects the high frequency distribution in the heating chamber. Accordingly, the arrangement of the metal post for matching has been determined to be a practical configuration while achieving both effective use of high-frequency energy and optimization of the high-frequency distribution.
[0007]
On the other hand, from the viewpoint of uniformly heating an object to be heated, there is a prior art relating to a method of causing high-frequency radiation into the heating chamber, in addition to a method of rotating the object to be heated and a method of stirring the high frequency in the heating chamber.
[0008]
Conventional techniques related to high-frequency radiation include a configuration in which a plurality of high-frequency generation means are provided, and the high-frequency energy generated by the high-frequency generation means is radiated from radiation sections provided on different wall surfaces of a substantially rectangular parallelepiped heating chamber. There exists a thing of a structure provided with several radiation | emission part on the same wall surface with respect to a means.
[0009]
As a configuration of the radiating unit, there are a configuration in which a substantially rectangular opening provided on the wall surface of the heating chamber is used as a radiating port and a configuration in which a radiating antenna is provided and rotated. Moreover, as a specific radiation | emission part structure, there exists a structure which added the square-shaped radiation | emission opening | mouth to the rectangular-shaped radiation | emission opening | mouth as shown by Unexamined-Japanese-Patent No. 2000-164341.
[0010]
[Problems to be solved by the invention]
However, the high frequency radiated from the conventional radiating section is a so-called vertical polarization propagation form and is analytically expressed as a sin function. When this vertically polarized wave propagates through the heating chamber, which is a closed space that houses the object to be heated, it repeats almost perfect reflection with a phase difference of 180 ° on the wall surface of the heating chamber. As a result, the heating chamber is identified by combining reflected waves. The standing wave is generated. This standing wave distribution varies greatly depending on the type, amount, or shape of the object to be heated, but in the same object to be heated, it hardly changes even if the object to be heated is rotated, so it promotes uniform heating of the object to be heated. There was a limit in planning. On the other hand, the agitation of the radio wave agitating means can cause a great change, but the load matching state with the high frequency generating means also greatly fluctuates, so that there is a problem that the effective utilization of the high frequency energy is reduced.
[0011]
The present invention solves the above problems, and provides a device for efficiently and uniformly high-frequency heating an object to be heated by devising the shape of the radiant port so that the radiation distribution to the heating chamber has a radiation characteristic different from the conventional one. For the purpose.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problem, the high-frequency heating device of the present invention transmits a high frequency to a heating chamber for storing an object to be heated, a plurality of L-shaped radiant ports provided on the bottom surface of the heating chamber, and the radiant port. And a plurality of L-shaped radiating ports, with a point on the tube axis of the rectangular waveguide as a symmetric point, and heating in the vicinity of the radiating port. An opening provided on the wall of the chamber and having a longitudinal dimension in the tube axis direction of the rectangular waveguide, and an impedance variable means for changing the high-frequency impedance in the opening are provided .
[0013]
According to the above invention, by arranging a plurality of L-shaped radiation ports symmetrically, the direction of the electric field exciting each radiation port (or the direction in which the high-frequency current flows) is different from each other. The radiated high frequency is combined or repelled in the vicinity of the radiant aperture to form a wide radiation distribution around the radiant aperture. This behavior near the radiation port mitigates the influence on the high-frequency generating means due to the difference in the amount and shape of the object to be heated, and allows the high-frequency generating means to operate stably for various objects to be heated. It is possible to enhance the utilization efficiency and promote uniform heating. In addition, by changing the impedance of the opening, it is possible to deflect a wide range of high-frequency distribution formed in the vicinity of the radiation port, and simultaneously finish multiple heated objects of different types, amounts, or temperatures without moving the heated object can do.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is a heating chamber for storing an object to be heated, a plurality of L-shaped radiation ports provided on the bottom surface of the heating chamber, and a rectangular waveguide for transmitting a high frequency to the radiation port. A tube, an opening provided on a wall surface of the heating chamber in the vicinity of the radiation port, the opening having a longitudinal dimension in the tube axis direction of the rectangular waveguide, and impedance varying means for changing a high-frequency impedance in the opening Can change the impedance of the opening and deflect a wide range of high-frequency distribution formed in the vicinity of the radiating port. The objects to be heated can be finished simultaneously.
[0015]
According to a second aspect of the present invention, there is provided a heating chamber for storing an object to be heated, a plurality of L-shaped radiation ports provided on the bottom surface of the heating chamber, and a rectangular waveguide for transmitting a high frequency to the radiation port. A tube, a rotating body made of a substantially circular metal plate provided above the radiation port, and a longitudinal dimension in the tube axis direction of the rectangular waveguide provided on the heating chamber bottom wall surface in the vicinity of the radiation port. A plurality of objects to be heated and flat objects to be heated by deflecting a radiation distribution from a rotating body, comprising an opening having a direction and impedance changing means for changing a high-frequency impedance in the opening. The heating can be made uniform.
[0016]
In the invention described in claim 3, in particular, the plurality of L-shaped radiating ports according to claim 1 or 2 have a configuration in which a point on the tube axis of a rectangular waveguide is a symmetric point. With this, the direction of the electric field that excites each radiation port becomes a different direction, and high-frequency radiation radiated from each radiation port can be combined or repelled near the radiation port to form a wide radiation distribution around the radiation port. . This behavior near the radiation port mitigates the influence on the high-frequency generating means due to the difference in the amount and shape of the object to be heated, and allows the high-frequency generating means to operate stably for various objects to be heated. It is possible to enhance the utilization efficiency and promote uniform heating.
[0017]
The invention described in claim 4 is the one in which the output part of the high-frequency generating means is disposed at the position of the symmetry point described in claim 3 in particular, so that the direction of the electric field for exciting each radiation port is surely different. Furthermore, since the radiation opening is excited by strong electromagnetic wave energy at the output part of the high frequency generating means, the radiation distribution can be made wider and the waveguide can be made compact.
[0018]
In the invention of claim 5 , in particular, the plurality of L-shaped radiation ports of claim 2 have a point on the tube axis of the rectangular waveguide as a symmetry point, and the rotating body rotates the symmetry point. Consists of a central configuration, so that the direction of the electric field that excites each radiation port becomes a different direction, and the high frequency radiated from each radiation port is combined and repelled in the vicinity of the radiation port so that it is wide around the radiation port. A radiation distribution can be formed. And since the rotating body protects this radiation distribution, the influence on the high-frequency generating means due to the difference in the amount and shape of the object to be heated is alleviated, and the high-frequency generating means can be operated stably with respect to various objects to be heated. It is possible to increase the efficiency of energy use and promote uniform heating.
[0019]
In the invention according to claim 6 , in particular, the maximum interval in the tube axis direction of the rectangular waveguide of the plurality of radiation ports according to claim 1 or 2 is a high-frequency transmission wavelength transmitted through the waveguide. The direction of the high-frequency electric field that crosses each radiation port can be defined in opposite directions, and the omnidirectional radiation direction can be reliably achieved.
[0020]
In the invention described in claim 7 , in particular, the plurality of radiation ports according to claim 1 or 2 are configured so as not to cross the tube axis of the rectangular waveguide, and the radiation located on the high frequency generating means side is provided. The radiation energy from the mouth can be suppressed and high frequency excitation of each radiation mouth can be guaranteed.
[0021]
In the invention described in claim 8 , in particular, a plurality of openings according to claim 1 or 2 are arranged with the tube axis of the rectangular waveguide being axially symmetric, corresponding to impedance changes of the openings. Therefore, it is possible to simplify the identification of the deflection direction of the high-frequency distribution that changes and to improve the convenience in simultaneous heating of different objects to be heated.
[0022]
In the ninth aspect of the present invention, in particular, the impedance variable means according to the first or second aspect includes a groove portion having an opening as one end and the other end closed, a plate-like movable plate provided in the groove portion, The movable plate comprises movable means for rotating or sliding the movable plate, whereby the impedance of the opening can be changed over a wide range without leaking high frequency.
[0023]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0024]
Example 1
1 is a front cross-sectional configuration diagram of a high-frequency heating device showing Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. 1, and FIG. 3 is a front view showing a control example of the impedance variable means in FIG. 4 is a cross-sectional configuration diagram, FIG. 4 is a high-frequency electric field distribution by the radiation port of FIG. 1, and FIG. 5 is an enlarged configuration diagram of the impedance variable means of FIG.
[0025]
In the figure, 10 is a heating chamber for storing an object to be heated, 11 is a waveguide having a substantially rectangular cross section, and is provided with an insertion hole 12 for mounting a high frequency generating means (not shown) at one end. Further, radiation ports 14 a and 14 b provided on the bottom wall surface 13 of the heating chamber 10 are disposed at the other end of the waveguide 11. 15 is a placing plate made of a dielectric material on which the object to be heated is placed, 16a and 16b are openings provided on the bottom wall surface 13 of the heating chamber, and 17a and 17b are spatial impedances at the openings 16a and 16b, respectively. An impedance varying means 18 is an open / close door for taking an object into and out of the heating chamber 10.
[0026]
The radiating ports 14a and 14b have a waveguide end face 19 on the side far from the side where the high frequency generating means of the waveguide 11 is mounted, and a distance of about ½ of the transmission wavelength of the frequency transmitted from the end face 19 to the waveguide 11. It is arrange | positioned on the wall surface (H surface of a waveguide) between the only distance positions. The radiating ports 14a and 14b are each composed of an L-shaped opening and are arranged point-symmetrically. The point-symmetrical position is on the tube axis 20 of the waveguide 11 and is indicated by an x mark 21 in FIG. The openings of the radiation ports 14 a and 14 b have a portion parallel to the tube axis 20 and a portion perpendicular to the tube axis 20, and the openings are arranged so as not to cross the tube axis 20.
[0027]
Further, the longitudinal direction of the openings 16a and 16b is set to the tube axis direction of the rectangular waveguide 11, and the tube axis of the rectangular waveguide 11 is arranged to be axially symmetrical.
[0028]
Next, the main operation of the above configuration will be described. A high-frequency current as indicated by arrows 22 to 25 in FIG. 2 flows through the waveguide wall surface, and a high-frequency electric field in the direction indicated by arrows 22 to 25 is similarly generated at the L-shaped radiation openings 14a and 14b. The high-frequency electric fields 22 and 23 crossing the opening in one L-shaped radiation port 14a are substantially orthogonal to each other, and the phase of the high frequency transmitted through the waveguide 11 corresponds to a phase difference of about 90 degrees. The same applies to the radiation port 14b. Then, due to the high frequency radiated from the radiation ports 14a and 14b excited by such a high frequency electric field, a high frequency electric field distribution as shown in FIG. 4 is generated around the radiation port. That is, the region where the electric field is strong appears at the point-symmetrical position of the L-shaped radiation port, and the high-frequency wave propagates in the direction perpendicular to the tube axis of the waveguide 11. The point where the point symmetry position has a strong electric field strength is due to the fact that the high frequency radiated from each radiation port is coupled in the vicinity of the radiation port. And the high frequency radiated | emitted from each radiation aperture couple | bonds or repels in the radiation aperture vicinity, and forms wide radiation distribution around a radiation aperture. Due to the behavior near the radiation port, the influence on the high-frequency generating means due to the difference in the amount and shape of the object to be heated is mitigated, and the high-frequency generating means can be stably operated with respect to the object to be heated in various ranges. Energy utilization efficiency can be increased. In addition, by providing such a radiation port on the bottom surface of the heating chamber and placing the object to be heated in the vicinity of the upper part of the radiation port, the object to be heated is encased by the high-frequency distribution produced by the radiation port. Thus, high-frequency heating can be performed with high energy utilization efficiency.
[0029]
Further, the direction of the longitudinal dimension of the openings 16a and 16b is set to the tube axis direction of the rectangular waveguide 11, so that the high-frequency radiation direction from the radiation port due to the impedance change of the opening is changed more strongly. Can do. Further, by arranging the tube axis of the rectangular waveguide 11 to be axially symmetric, it is possible to simplify the identification of the deflection direction of the high-frequency distribution that changes corresponding to the impedance change of the opening, and simultaneously heat different objects to be heated. Convenience can be improved.
[0030]
In FIG. 4, the reason why the high-frequency electric field distribution is not symmetric with respect to the tube axis of the waveguide is that the radiation energy from the radiation port on the high-frequency generating means side is strong, and the opening shape of this radiation port It is possible to improve the symmetry by reducing.
[0031]
Further, as specific configuration dimensions of the present embodiment, the width dimension of the waveguide 11 is 80 mm, and the width dimension of the L-shaped opening is 20 mm.
[0032]
Next, the configuration and operation of the impedance varying means will be described with reference to FIG. In FIG. 5, the impedance varying means 50 has a box-shaped portion 51 made of a metal member as a main body, and is configured to form a groove portion by being assembled and mounted on the heating chamber wall surface. In the box-shaped part 51, a rotating plate 52 having a plate-like structure as a movable plate is provided. Rotating shafts 53 and 54 for rotating the rotating plate 52 are provided at both ends of the rotating plate 52, and the rotating shaft 53 is inserted into a hole provided in the wall surface of the box-shaped portion 51 and is rotatably supported by the hole. On the other hand, the rotary shaft 54 is connected to the output shaft of a stepping motor 55 (movable means) which is means for rotating the rotary plate 52. Reference numeral 56 denotes a light shielding portion for detecting the rotation angle provided on the rotation shaft 54, and a photo interrupter (not shown) is used as the rotation angle detecting means. Reference numerals 57 to 60 are heating chamber mounting flanges which are spot-welded and assembled to the heating chamber wall surface. 61 is a hole for mounting the rotating plate 52 in the box-shaped part 51. As specific dimensions of the box-shaped part 51, the width is 80 mm, the length is La + Lb, and the height is 20 mm. La and Lb dimensions are the lengths from the center of the rotating plate 52 to the respective end faces of the box-shaped part 51. When the impedance variable means having such a configuration is mounted in the heating chamber, the opening 62 (16a and 16b in FIG. 2) is disposed at a predetermined position on the La dimension side of the box-shaped portion 52. As a result, the end of the groove portion formed by the box portion 51 and the heating chamber wall surface is a wall surface 63 forming the box portion 51 in FIG. The support angle of the rotating plate 52 defines the state where the wide surface 52a of the rotating plate 52 is substantially parallel to the wall surface 63 as 0 degree.
[0033]
The rotating plate 52 has a heat resistant temperature of 200 ° C. or higher and a non-metallic material of a resin material or an inorganic material having a low dielectric loss characteristic in a frequency band used by the apparatus, and the base material has a predetermined plate thickness. In addition, each is formed or fired. Next, the operation and action of the impedance varying means 50 will be described. The impedance variable means can be configured such that La = 30 mm and Lb = 20 mm to vary the phase value of the voltage reflection coefficient S11 at the opening 62 in a range of approximately ± 180 degrees to approximately −30 degrees. That is, in this case, by rotating the rotating plate 52, an impedance in which the capacitive reactance component is changed can be formed in the opening 62. Further, by adopting the configuration of La = 50 mm and Lb = 20 mm, the phase value of the voltage reflection coefficient S11 at the opening can be varied from approximately +90 degrees to ± 180 degrees through approximately −135 degrees. That is, in this case, when the rotating plate 52 is rotated, the inductive reactance component (phase value range: +90 degrees to ± 180 degrees) and the capacitive reactance component (phase value range: ± 180 degrees are approximately − 135 degrees) value can be present. Furthermore, by adopting a configuration of La = 70 mm and Lb = 20 mm, the phase value of the voltage reflection coefficient S11 at the opening 62 can be varied from approximately +0 degrees to +90 degrees to a range of approximately ± 180 degrees. That is, in this case, by rotating the rotating plate 52, the opening 62 can have an impedance in which the inductive reactance component changes.
[0034]
When the phase value of the voltage reflection coefficient at the opening is approximately ± 180 degrees, that is, when the impedance of the opening is approximately zero, the opening can be operated in the same manner as the metal wall surface.
[0035]
When the support angle of the rotating plate 52 is changed, the impedance of the opening 62 is changed, and the phase difference between the high frequency incident wave and the reflected wave at the opening 62 can be changed. The phase difference between the high frequency incident wave and the reflected wave on the metal wall surface of the heating chamber 10 is 180 degrees. On the other hand, the phase difference between the incident wave and the reflected wave at the opening provided on the metal wall surface is 180 degrees when the impedance value of the opening is zero, 0 degrees when the impedance value is infinite, and in the case of inductive reactance. The phase of the reflected wave is delayed with respect to the incident wave, and the phase is advanced in the case of capacitive reactance. The apparent size of the heating chamber changes with the change in phase between the incident wave and the reflected wave. In the case of inductive reactance, the size of the heating chamber is apparently larger than the radio wave effect, whereas in the case of capacitive reactance, it is reduced. This is, for example, to change the apparent distance between the object to be heated housed in the heating chamber and the radiation port. By utilizing this phenomenon, the heating area on the plane of the object to be heated can be changed, or the heating area in the height direction of the object to be heated can be changed, and the object to be heated can be moved without moving the object to be heated. Heating can be made uniform, and for example, a plurality of objects to be heated of different types / amounts or temperatures can be simultaneously finished.
[0036]
Further, the openings are arranged as shown in FIG. 2, and the high frequency distribution in the heating chamber is deflected in the vertical and horizontal directions of the heating chamber by controlling the rotation of the movable plate of the impedance variable means corresponding to each opening. Can be made. FIG. 3 shows an example of this, in which the support angles of the rotary plates 26a and 26b, which are constituent members of the impedance varying means 17a and 17b, are set to 0 degrees and 90 degrees, respectively, thereby reducing the spatial impedance at the opening 16b. Make it almost infinite. As a result, the radiation distribution can be deflected toward the opening 16a. By utilizing these action phenomena, it is possible to variably control the heating region of the object to be heated without rotating the object to be heated, thereby heating the object to be heated uniformly.
[0037]
In the above description, the movable plate is rotated. However, the movable plate may be slid parallel to the end of the groove.
[0038]
(Example 2)
Next, Embodiment 2 of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in that the high-frequency generating means is provided at a point-symmetrical position of the L-shaped radiation port.
[0039]
That is, in the figure, 70 is a rectangular waveguide, and 71 is an insertion hole for inserting and mounting the output portion of the high-frequency generating means. The insertion hole 71 corresponds to a point-symmetrical position of the L-shaped radiation ports 72a and 72b.
[0040]
With this configuration, the direction of the electric field for exciting each radiation aperture can be made different, and the radiation aperture is excited with strong electromagnetic wave energy at the output of the high frequency generating means, so that the radiation distribution can be made wider and guided. The tube can be made compact.
[0041]
(Example 3)
Next, a third embodiment of the present invention will be described with reference to FIGS. Example 3 differs from Example 1 and Example 2 in the configuration in which a rotating body is disposed above an L-shaped radiation port provided on the heating chamber wall surface. In addition, the same member as Example 1 or the same equivalent member is shown with the same number, and description is abbreviate | omitted.
[0042]
That is, in FIG. 8, the radiation ports 14 a and 14 b having L-shaped openings are arranged on the terminal side of the rectangular waveguide 11 so as to be point-symmetric with respect to the point on the tube axis of the waveguide 11. ing. A substantially circular metal plate 73 as a rotating body is provided above the plurality of radiation openings 14a, 14b. The metal plate 73 is configured to be rotationally driven with the point symmetry positions of the plurality of radiation openings as the center of rotation. That is, a metal support 74 connected to the central portion of the substantially circular shape of the metal plate 73, a support portion 75 made of a low dielectric loss material that supports the metal support 74, and a low dielectric loss material fitted to the metal support 74. A motor 77 having an output shaft 76 is provided. In addition, openings 78 a and 78 b similar to the L-shaped openings provided in the waveguide 11 are provided in the metal plate 73 that is a rotating body.
[0043]
With this configuration, heating of the object to be heated is made uniform by radiating high-frequency waves from the rotating body to the object to be heated while protecting the radiation distribution formed by the L-shaped radiation port by the metallic rotating body. Can be promoted.
[0044]
Further, similarly to the first embodiment, provided with openings 16a and 16b provided on the bottom wall surface of the heating chamber near the radiation opening, and impedance variable means 17a and 17b for changing high-frequency impedances in the openings 16a and 16b, respectively. Thus, it is possible to promote uniform heating of a plurality of objects to be heated and flat objects to be heated by deflecting the radiation distribution from the rotating body.
[0045]
In addition, the shape of the metal plate 73 that is a rotating body may be a configuration that permits a radiation distribution that is expressed by a radiation port including a plurality of L-shaped openings, and may be, for example, a substantially rectangular shape or a fan shape. . Further, the metal plate 73 may be driven to rotate eccentrically. Moreover, the shape of the opening provided in the metal plate 73 is not limited to the L-shape, and a plurality of openings may be arranged with the longitudinal directions of the rectangular shapes orthogonal to each other, for example.
[0046]
In the above, it is desirable from the viewpoint of processing and suppressing the occurrence of sparks by the edge portion that the corner portion of each radiation port is appropriately rounded. The range of change in impedance of the opening is not limited to the above description. For example, when the support angle of the rotating plate is 90 degrees, the variable range of only the inductive component can be obtained by setting the spatial impedance in the opening to be substantially zero. Or, when the support angle of the rotating plate is approximately 45 degrees, the variable impedance including both the inductive component and the capacitive component can be set by setting the spatial impedance at the opening to substantially zero.
[0047]
【The invention's effect】
As described above, according to the present invention, by arranging a plurality of L-shaped radiation ports in point symmetry, the directions of the electric fields that excite the radiation ports are different from each other, and the high frequencies radiated from the radiation ports are different. Are combined or repelled in the vicinity of the radiation aperture to form a wide radiation distribution around the radiation aperture. In addition, the configuration in which such a radiation port is provided on the bottom surface of the heating chamber and the object to be heated is arranged in the vicinity of the heating chamber reduces the influence on the high frequency generation means due to the amount and shape of the object to be heated. In contrast, the high-frequency generating means can be operated stably, and the energy use efficiency can be increased.
[0048]
In addition, by providing an opening provided on the bottom surface of the heating chamber and impedance variable means for changing the high-frequency impedance in the opening, the impedance of the opening is changed to deflect the high-frequency distribution formed around the radiation port. Uniform heating can be promoted without changing and moving the object to be heated.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a high-frequency heating device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA ′ of the high-frequency heating device. FIG. 4 is a front cross-sectional view of the high-frequency heating apparatus. FIG. 5 is a configuration diagram of impedance variable means of the high-frequency heating apparatus. FIG. 6 is a cross-sectional configuration of the high-frequency heating apparatus according to the second embodiment of the present invention. FIG. 7 is a front sectional view of a high-frequency heating device according to a third embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line BB ′ of the high-frequency heating device.
DESCRIPTION OF SYMBOLS 10 Heating chamber 11,70 Rectangular-shaped waveguide 13 Bottom surface of heating chamber 14a, 14b, 72a, 72b L-shaped radiation port 16a, 16b Opening portion 17a, 17b, 50 Impedance variable means 20 Tube axis 21, 71 points Symmetric position 26a, 26b, 52 Rotating plate (movable plate)
73 Rotating body

Claims (9)

A heating chamber for storing an object to be heated, a plurality of L-shaped radiation ports provided on the bottom surface of the heating chamber, a rectangular waveguide for transmitting a high frequency to the radiation port, and a vicinity of the radiation port A high-frequency heating apparatus comprising: an opening provided on a heating chamber wall surface, the opening having a longitudinal dimension disposed in a tube axis direction of the rectangular waveguide; and impedance variable means for changing a high-frequency impedance in the opening. A heating chamber for storing an object to be heated, a plurality of L-shaped radiation ports provided on the bottom surface of the heating chamber, a rectangular waveguide for transmitting a high frequency to the radiation port, and above the radiation port A rotating body made of a substantially circular metal plate provided, an opening provided on the bottom wall surface of the heating chamber in the vicinity of the radiation port, and a longitudinal dimension in the tube axis direction of the rectangular waveguide ; A high-frequency heating apparatus comprising impedance varying means for changing a high-frequency impedance in the opening.   The high-frequency heating device according to claim 1 or 2, wherein the plurality of L-shaped radiation ports have a configuration in which a point on a tube axis of a rectangular waveguide is a symmetric point.   The high frequency heating apparatus according to claim 3, wherein an output portion of the high frequency generating means is disposed at the position of the symmetry point. The high-frequency heating device according to claim 2, wherein the plurality of L-shaped radiating ports have a configuration in which a point on the tube axis of the rectangular waveguide is a symmetric point, and the rotating body has the symmetric point as a center of rotation. . The high frequency heating apparatus according to claim 1 or 2 , wherein a maximum interval in the tube axis direction of the rectangular waveguide of the plurality of radiation openings is approximately ½ of a transmission wavelength of a high frequency transmitted through the waveguide. The high-frequency heating device according to claim 1 or 2, wherein the plurality of radiation openings are configured not to cross a tube axis of a rectangular waveguide. The high-frequency heating device according to claim 1 or 2, wherein a plurality of openings are arranged with the axis of the rectangular waveguide being axially symmetrical. Impedance varying means includes a groove and the other end to one end of the opening is closed, and the plate-shaped movable plate provided in said groove, and a movable means for rotating or sliding the movable plate according to claim 1 or 2 The high-frequency heating device described.

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