JPS61294789A - High frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-frequency heating device for high-frequency heating of an object to be heated, such as food, using radio waves.

2. Description of the Related Art In general, when a high-frequency heating device heats an object, the most important point is whether or not the object is heated evenly and uniformly. Conventionally, in order to obtain more uniform heating characteristics, there is a stirrer type that stirs the radio waves incident on the heating chamber, a turntable type that rotates the object to be heated within the heating chamber, and a waveguide 1 type as shown in Figure 5. A secondary radiation antenna 3 is provided at the power feeding port (opening) 1 & on the wall facing the heating chamber 2, and the antenna is radiated into the heating chamber 2 to change the electric field pattern (for example,
Publication No. 0).

Problems to be Solved by the Invention However, in the above configuration, the turntable and stirrer type are rotated by a motor or wind power, and although their uniform heating characteristics are good, the structure is complicated and expensive. , the effective volume within the heating chamber is also limited. On the other hand, with the secondary radiation antenna type, the intensity of the radio waves radiated directly into the heating chamber from the waveguide opening and the radio waves radiated from the secondary radiation antenna are effectively loaded depending on the dielectric constant and shape of the heated object. Because the impedance (including the heating chamber) changes greatly, even if the power supply port is placed in the center of the heating chamber, an imbalance of electric fields will occur between the front, rear, left and right sides of the heating chamber, resulting in radio wave agitation such as the aforementioned turntable method or stirrer one-way method. This had problems such as not being able to withstand practical use unless the structure was used in combination.

The present invention solves these conventional problems,
The purpose is to uniformly heat a heated object with a simple configuration.

Ninth Means for Solving the Problems In order to solve the above problems, the high frequency heating device of the present invention includes a waveguide having an approximately rectangular heating chamber power supply port in the excitation mode of the TE10 and the H plane, and the heating It has a structure in which a crosspiece is provided to divide the room power supply port into a plurality of parts in the direction of radio wave propagation of the waveguide.

Function: The high-frequency heating device of the present invention converts the excitation mode in the waveguide into TE.
10, the wall surface facing the heating chamber of the waveguide is arranged so as to form an H plane, and a substantially rectangular power supply port is provided on the H surface, and the power supply port has a plurality of power supply ports in the direction of radio wave propagation within the waveguide. By providing separate crosspieces, multiple slit antennas can be formed in the waveguide, and the electric field of high-frequency radio waves radiated from each slit antenna has the same phase, so that Uniform 1. This provides heating properties.

EXAMPLE Hereinafter, a high frequency heating device according to an example of the present invention will be described with reference to the drawings.

In FIG. 1, the high frequency electromagnetic wave oscillated by the high frequency oscillator 3 excites the mode of TE 10 in the waveguide 4. In FIG. T
In the E10 mode, the waveguide wall facing the heating chamber 5 is H
The waveguide 4 is arranged so as to form a plane. The waveguide H
Approximately in the center of the heating chamber 5 on the surface, a substantially rectangular power supply port 6 is provided which radiates the electromagnetic waves propagated through the waveguide 4t into the heating chamber. It is divided into two parts by a crosspiece 7 formed in .

These divided feeding ports (slit antennas) 6a, 6b
The high frequency electromagnetic waves supplied to the heating chamber 5 are as follows.

The structure is such that high-frequency energy is emitted to an object to be heated 9 placed on a shelf board 8 made of a low dielectric material and supported on the wall of the heating chamber.

the above! ! In this case, the distribution of the wall current of the waveguide 4 excited in the TE10 mode is as shown by the solid arrow in FIG. When opening a power supply port in the waveguide 4, it is necessary to cut off the wall current and change the path of the power supply port so that it is arranged in a direction that radiates high frequency electromagnetic waves to the outside.

° Therefore, 2. Normally, when opening the power supply port on the H side.

As shown in A in the figure, the space is perpendicular to the direction of radio wave propagation.

The power feeding section of the present invention is divided into a plurality of parts by a crosspiece 7, and each power feeding port (slit antenna) 6a, 6b is parallel to the direction of radio wave propagation, and is perpendicular to the wall current distribution. The high-frequency electric field radiated from the power supply port, which is divided into multiple parts in the direction, has the same phase, and the intensity is uniform on the front, back, left and right sides of the heating chamber, and the object to be heated can be heated evenly. effective. The feed port that cuts off the wall current and radiates high-frequency electromagnetic waves acts as a slit antenna, and the circumference of the feed port is approximately one wavelength (approximately 12
If α) is chosen, the radiation will be best.

Next, a second embodiment of the present invention will be described with reference to FIG.

The difference in FIG. 3 from the first embodiment is that the feed port 6 is divided into four parts by the crosspiece 7. According to this structure, if the maximum radiation dimension of the slit antenna is selected to be one wavelength, Individual feed port (slit antenna) 611.6
b, 6c, and 6d are located over a wide range of the heating chamber, which has the effect of further improving uniform heating characteristics.

Next, a third embodiment of the present invention will be described using FIG. 4.

The difference in FIG. 4 from the first embodiment described above is that the crosspiece 7a that divides the power supply port 6 into a plurality of parts 6e and 6f has a FIl configuration that is uneven in the direction of radio wave propagation. According to the method, the transmission loss in the waveguide 4 (the longer the transmission path is, the greater it is), and the farther from the high-frequency oscillator 3 the wall current is cut off, increasing the rate of wall current cutting, thereby increasing the strength of the emitted high-frequency electric field. This has the effect of uniformly correcting it.

1. It goes without saying that even if a radio wave agitation structure such as a starrer type or a turntable type is used in conjunction with the configuration of the present invention, the effects of the invention will not be impaired.

Effects of the Invention As described above, the high frequency heating device of the present invention provides the following effects.

(1) Since multiple feed ports are arranged on the H-plane of the waveguide perpendicular to the tube axis direction, the high-frequency electromagnetic waves radiated as a slit antenna have the same phase 1 intensity and are uniform. Heating properties can be obtained.

(2) Since the configuration is simple and requires no additional parts or structures by simply providing multiple power feed ports on the waveguide wall, it is possible to provide a high-frequency heating device with uniform heating characteristics at low cost. .

[Brief explanation of the drawing]

FIG. 1 is a transparent perspective view of a high-frequency heating device according to a first embodiment of the present invention, FIG. 2 is a perspective view showing the distribution of wall current in the waveguide, and FIG. 3 is a perspective view of a second embodiment of the present invention. FIG. 4 is a perspective view of a waveguide showing an example, FIG. 4 is a plan view of a waveguide showing a third embodiment of the present invention, and FIG. 5 is a front sectional view of a conventional high-frequency heating device. 3... High frequency oscillator, 4... Waveguide,
5... Heating chamber, 6... Power supply port, 6a,
6b, 6c16d...Slit antenna, 7.
・・・・・・Sambe. Name of agent: Patent attorney Toshio Nakao and 1 other person3-
11 south and development plan each 4-11 lead 2Lf 5-11 force tr sale ~ 1 [Fig. ---Guide: LY; f--Ichiiso

Claims (3)

[Claims] (1) A heating chamber, a high-frequency oscillator that supplies high-frequency energy to the heating chamber, and a waveguide that propagates high-frequency waves from the high-frequency oscillator to the heating chamber, the waveguide having T
A high-frequency heating device that has an approximately rectangular heating chamber power supply port on the H plane and an excitation mode of E_1_0, and is provided with a crosspiece that divides the heating chamber power supply port into a plurality of pieces in the direction of radio wave propagation in a waveguide. (2) The high-frequency heating device according to claim 1, wherein the crosspiece is configured non-uniformly with respect to the direction of radio wave propagation. (3) The high-frequency heating device according to claim 1, wherein the circumferential length of each of the plurality of power feed ports divided by the crosspiece is approximately one wavelength of radio waves.