JP3619044B2 - High frequency heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency heating apparatus that is provided with a power supply port below a heating chamber and irradiates a high frequency from the lower part of an object to be heated.
[0002]
[Prior art]
FIG. 6 is a front sectional view showing a conventional high-frequency heating device. In the figure, 1 is the object to be heated, 2 heating chamber 3 is high-frequency oscillator is an oscillation source of high frequency, 4 denotes a control unit for controlling the high frequency oscillator 3, 5 transmits a high frequency into the heating chamber 2 from the high frequency oscillator 3 Waveguides 6 are power supply ports at the boundary between the waveguide 5 and the heating chamber 2, and are formed at, for example, two locations above and below the side surface of the heating chamber 2. 7 is a heated object mounting base formed of a low dielectric constant material such as glass on which the heated object 1 is placed, 9 is a rotary plate that supports the heated object mounting base 7 on which the heated object 1 is placed, A motor that rotates the rotary plate 9.
[0003]
Next, the operation will be described.
The high frequency oscillated by the high frequency oscillator 3 propagates through the waveguide 5 and is propagated to the heating chamber 2 from the upper and lower power supply ports 6 and rotates while repeating incidence and reflection on the wall surface of the heating chamber 2. The object to be heated 1 placed on 9 is irradiated. Thereby, the article 1 to be heated is heated.
[0004]
However, in the above conventional example, since the waveguide 5 is installed on the side surface of the heating chamber 2, the distance between the power supply port 6 and the object to be heated 1 becomes long. Therefore, the high frequency incident on the heating chamber 2 from the power supply port 6 is not directly absorbed by the heated object 1 but is absorbed by the heated object 1 after repeating incident reflection on the wall surface of the heating chamber 2. For this reason, there existed a problem that energy loss generate | occur | produced by the attenuation | damping by absorption to the heating chamber 2 wall surface.
[0005]
Further, since a high frequency is incident from the side surface of the heating chamber 2, the side surface and the upper surface of the object to be heated 1 are easily heated with a large amount of microwave irradiation. Since it is difficult to irradiate the object to be heated 1 by being reflected by the metal rotary plate 9 placed thereon, and the distance between the object to be heated 1 and the bottom surface of the heating chamber 2 is short, it is incident on the lower surface of the object to be heated 1. The microwave component to be reduced is less likely to be heated. Therefore, there is a problem that uneven heating occurs.
[0006]
In order to solve the above-described problems, another conventional example, for example, a high-frequency heating device disclosed in Japanese Patent Application Laid-Open No. 58-175284 has been proposed. FIG. 7 is a front cross-sectional view showing another conventional high-frequency heating apparatus, and 11 is a slot formed at a coupling portion between the heating chamber 2 and the waveguide 5, and a plurality of slots 11 are provided to form a slot antenna array. Forming. Reference numeral 12 denotes a metal piece 12 provided in the waveguide 5 and provided between the slot 11 and the slot 11 for adjusting the radiant energy from both the slots 11.
[0007]
According to another conventional example, heating unevenness can be suppressed by the slot antenna array having the metal piece 12 for adjusting the high frequency radiation energy between the slots 11 and the rotary plate 9.
[0008]
[Problems to be solved by the invention]
However, in another conventional example, the rotary plate 9 is rotated to have a complicated structure, the number of parts is increased, the failure rate is increased, the reliability is not high, and the electromagnetic wave shielding mechanism of the roller and rotary plate drive unit is difficult. There is a problem of becoming. In addition, since the rotary plate 9 and the like are in the heating chamber 2, there are problems such as a reduction in effective use space in the heating chamber 2 and deterioration in cleanability.
[0009]
In addition, since the distance between the object to be heated 1 and the power feeding port 6 (slot antenna array 11) becomes long and is absorbed by the object to be heated 1, high frequencies radiate in multiple directions. Without high efficiency. Further, since the waveguide 5 is provided in the upper part of the heating chamber 2, when heating a liquid such as milk or liquor, the upper part is closer to the slot antenna array than the lower part of the object to be heated 1, and overheating is caused. There was a problem that occurred.
[0010]
The present invention has been made to solve the above-described problems, and it is possible to expand the effective space of a heating chamber and to uniformly heat an object to be heated with high efficiency.
[0011]
[Means for Solving the Problems]
High-frequency heating apparatus according to the present invention includes a heating chamber for accommodating an object to be heated, and a high-frequency oscillation means for oscillating a high frequency, the high frequency oscillated from the high frequency oscillation means is provided in the lower portion of the heating chamber from the heating chamber bottom A high-frequency heating apparatus comprising: a waveguide to be transmitted; a power supply port formed at a boundary between the heating chamber and the waveguide; and a mounting unit that is disposed above the power supply port and places the object to be heated. The shape of the power supply port and the shape of the waveguide below the heating chamber are both rectangular, or the shape of the power supply port and the shape of the portion below the power supply port of the waveguide are both circular. A rectangular metal piece electrically coupled to the waveguide within the waveguide and below the feeding port in the lower portion of the mouth and having a side length of a quarter wavelength or more is the high-frequency oscillation means. Position parallel to the direction of high-frequency oscillation It is those provided.
[0012]
Further, the shape of the power feeding port and the lower portion of the waveguide power feeding port is made circular .
[0013]
Further, the shape of the power feeding port and the lower portion of the power feeding port of the waveguide is circular, and the metal piece is curved along the circular shape .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a sectional view showing a high-frequency heating device according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the waveguide shown in FIG. In the figure, the same parts as those in the conventional example described above are denoted by the same reference numerals, and the description thereof is omitted. Reference numeral 8 denotes a metal piece disposed in the waveguide 5 and below the power supply port 6. The metal piece 8 is electrically coupled to the waveguide 5, and the length of one side is a quarter wavelength (λ / 4) or more with respect to the wavelength (λ) of the high frequency. With this configuration, the metal piece 8 has an antenna effect of receiving a high frequency and strengthening the electric field near the metal piece 8. In Embodiment 1, for example, the vertical length is λ / 4 and the horizontal length is λ / 2. Further, power port 6 are disposed in the central portion of the bottom surface of the heating chamber 2, as shown in FIG. 2, shape 5a of the shape 6a of the feed opening 6 the heating chamber 2 under the waveguide 5 is rectangular Is formed.
[0015]
In the first embodiment, two metal pieces 8 are provided, but either one may be provided.
[0016]
Frequency oscillated by the high frequency oscillator 3 through the waveguide 5 is propagated into the heating chamber 2 from the feed opening 6 directly irradiated to the feed opening 6 above the object to be heated 1. At this time, since the installed metal piece 8 having a feed inlet 6 below the quarter wavelength (lambda / 4) or more in length, the high frequency oscillated from the high frequency oscillator 3 is metal antenna effect of the metal pieces 8 The high frequency energy can be concentrated in the vicinity of the piece 8, and the high frequency energy can be efficiently absorbed by the article 1 to be heated. In addition, since the power supply port 6 is formed in the lower part of the heating chamber 2 and the shape 5a of the waveguide 5 matches the shape 6a of the power supply port 6 , the reflection on the wall surface of the heating chamber is higher than the conventional one. The number of times is greatly reduced, and the high frequency energy is efficiently absorbed by the article 1 to be heated. For this reason, an energy loss can be reduced significantly.
[0017]
Moreover, since the metal piece 8 can concentrate high frequency energy near the center of the bottom surface, which is the lower part of the object 1 to be heated, particularly with respect to the heating of the object 1 that is a liquid such as milk, liquor, etc. Can be heated intensively, so that the whole can be heated uniformly by convection. In addition, overheating of the object to be heated 1 arranged in a plane can be prevented from being overheated at the end of the object to be heated and can be uniformly heated.
[0018]
Further, it is not necessary to provide a structure for rotating the rotary plate as compared with the conventional one, the number of parts is reduced, the failure rate is reduced, reliability can be obtained, and the radio wave shield structure is facilitated. Moreover, the effective space of a heating chamber can also be expanded.
[0019]
Embodiment 2. FIG.
FIG. 3 is a perspective view showing a waveguide of a high-frequency heating device according to Embodiment 2 of the present invention. In the figure, the same parts as those in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted. In the second embodiment, as shown in FIG. 3, the shape 5b feeding port 6 the lower part of the feed port 6 shape 6b and the waveguide 5 and a circular metal piece 8 be along the shape of the waveguide 5 Curved and installed. With this configuration, an effect equivalent to that of the first embodiment can be obtained.
[0020]
Embodiment 3 FIG.
FIG. 4 is a perspective view showing a waveguide of a high-frequency heating device according to Embodiment 3 of the present invention. In the figure, the same parts as those in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted. In the third embodiment, the metal piece 8 is arranged at a position parallel to the high-frequency propagation direction (arrow a) oscillated from the high-frequency oscillator 3.
[0021]
According to the third embodiment, in addition to the same effects as those of the first embodiment, it is electrically coupled to the waveguide below the object to be heated, and the length of one side is a quarter wavelength ( There lambda / 4) above, further, is provided with the parallel metal strip with respect to the propagation direction of the high frequency oscillated from the high-frequency oscillator, further enhanced more antenna effect of the metal strip, radio frequency energy is concentrated on the metal strip, High-frequency energy can be directly applied to the object to be heated above. Therefore, high-frequency energy can be efficiently absorbed by the object to be heated.
[0022]
Embodiment 4 FIG.
FIG. 5 is a perspective view showing a waveguide of a high-frequency heating device according to Embodiment 4 of the present invention. In the figure, the same parts as those in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted. In the third embodiment, the metal piece 8 is arranged so that the distance L to the side wall surface of the waveguide 5 is a quarter wavelength (λ / 4).
[0023]
According to the fourth embodiment, the high frequency oscillated by the high frequency oscillator 3 is directly irradiated object to be heated 1 via the waveguide 5 provided in the heating chamber 2 below. At this time, the length of one side in the waveguide 5 is a quarter wavelength (λ / 4) or more, and the distance from the side wall surface of the waveguide 5 is a quarter wavelength (λ / 4). Since the metal piece 8 arranged so as to be provided is provided, not only the antenna effect of the metal piece 8 installed in the waveguide 5 but also the metal piece 8 and the waveguide are oscillated from the high frequency oscillator 3. The antenna effect also occurs between the 5 side wall surfaces, and a wider range can be heated.
[0024]
Therefore, it is possible to efficiently and uniformly heat a food that needs to be heated uniformly over a wider range than a normal food, such as a food having a small thickness and a large area. For this reason, while being able to heat a to-be-heated material with high efficiency, energy loss can be reduced significantly.
[0025]
【The invention's effect】
Above As mentioned, according to the present invention, a heating chamber for accommodating an object to be heated, and a high-frequency oscillation means for oscillating a high frequency, the high frequency oscillated from the high frequency oscillation means is provided in the lower portion of the heating chamber heating A waveguide that transmits from the lower part of the chamber, a power supply port formed at a boundary between the heating chamber and the waveguide, and a mounting unit that is disposed above the power supply port and places the object to be heated. In the high-frequency heating device, the shape of the power feeding port and the shape of the waveguide under the heating chamber are both rectangular, or the shape of the power feeding port and the shape of the lower portion of the waveguide are both circular. wherein said a waveguide and the feed port of the length of the waveguide and electrically coupled to one side 4 minutes rectangular metal pieces over one wavelength of the downward feed opening beneath the portion of the tube Parallel to the propagation direction of the high frequency oscillated from the high frequency oscillation means Since there is provided the location, frequency oscillated from the high frequency oscillator hand stage high-frequency energy is concentrated at the antenna effect of the metal pieces installed in the waveguide, the RF energy to the object to be heated is directly above or near Can be directly irradiated and can be absorbed by the object to be heated with high efficiency. Thereby, energy loss can be reduced significantly.
[0026]
In addition, for example, since high-frequency energy can be concentrated near the bottom center of the object to be heated, especially with respect to heating of liquids such as milk and liquor, the whole is heated by convection by intensively heating under the object to be heated. Heated uniformly. Further, the object to be heated arranged in a plane is not overheated at the end, and can be heated uniformly.
[0027]
Moreover, since it is not necessary to provide a rotary plate etc., the effective use space in a warehouse can be expanded.
[0028]
Further, since the metal piece is disposed so as to be parallel to the traveling direction of the high frequency wave propagating in the waveguide, the antenna effect of the metal piece can be further enhanced.
[0029]
Since the distance between the metal piece and the wall surface of the waveguide is a quarter wavelength, not only the antenna effect of the metal piece but also the antenna effect is generated between the metal piece and the wall surface of the waveguide. Can be heated.
[0030]
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a first embodiment according to the present invention.
FIG. 2 is a perspective view of a waveguide showing Embodiment 1 according to the present invention.
FIG. 3 is a perspective view of a waveguide showing a second embodiment according to the present invention.
FIG. 4 is a perspective view of a waveguide showing a third embodiment according to the present invention.
FIG. 5 is a perspective view of a waveguide showing a fourth embodiment according to the present invention.
FIG. 6 is a front sectional view showing a conventional high-frequency heating device.
FIG. 7 is a front sectional view showing another conventional high-frequency heating device.
[Explanation of symbols]
1 object to be heated, 2 heating chamber, 3 high frequency oscillator , 4 control unit, 5 waveguide,
6 Power supply port, 7 Heated object installation base, 8 Metal piece, 9 Rotary plate,
10 Motor.

Claims (3)

A heating chamber for accommodating an object to be heated, and a high-frequency oscillation means for oscillating a high frequency, a waveguide for transmitting a high frequency oscillated from the high frequency oscillation means is provided in the lower portion of the heating chamber from the heating chamber bottom, the heating In a high-frequency heating apparatus comprising a power feeding port formed at a boundary between a chamber and the waveguide, and a placing means disposed on the power feeding port to place the object to be heated, the shape of the power feeding port and the The shape of the waveguide at the lower part of the heating chamber is rectangular, or the shape of the feeding port and the shape of the lower part of the feeding port of the waveguide are both circular, and the inside of the waveguide is in the lower part of the feeding port of the waveguide. In addition, a rectangular metal piece electrically coupled to the waveguide below the feeding port and having a side length of ¼ wavelength or more in the direction of propagation of the high frequency oscillated from the high frequency oscillation means. frequency, characterized in that provided at a position parallel for Heat equipment. 2. The high frequency heating apparatus according to claim 1, wherein the shape of the power feeding port and the lower portion of the power feeding port of the waveguide is circular . 2. The high-frequency heating device according to claim 1, wherein the power supply port and a portion of the waveguide below the power supply port have a circular shape, and the metal piece is curved along the circular shape .

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