JPS6219038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device, and an object of the present invention is to provide a heating device that is easy to use and has a good high-frequency distribution, especially when a large amount of objects to be heated is heated at once.

Conventionally, as a high-frequency heating device of this kind used mainly for commercial purposes, which cooks a large amount of objects to be heated at once, a device with a wide heating chamber as shown in FIG. 1 has been commercialized. That is, main body 1
A heating chamber 2 is provided inside the heating chamber 2, and the planar area of the heating chamber 2 is widened so that a plurality of objects 4 to be heated placed on a plate 3 can be placed therein. A plurality of magnetrons 5 were attached to the upper wall of the heating chamber 2 to increase the high frequency output, and a radio wave stirring spring 8 rotated by a motor 7 was installed in a space divided by a partition plate 6. Naturally, such a heating device has a drawback that the planar area of the heating device is large, and a large installation area is required when installing it in a kitchen appliance.

The present invention solves the above-mentioned drawbacks and provides a high-frequency heating chamber with good high-frequency distribution.One embodiment of the present invention will be described below with reference to the drawings.

The upper wall of the heating chamber 2 in the upper body 1 is heated by a rotating antenna 11 which is driven by a motor 7 at the center of a power feed port 10, with radio waves oscillated by a magnetron 5 guided through a waveguide 9. Radio waves are radiated into the room 2. Note that 12 is a partition plate that protects the rotating antenna 11, and 13 and 14 are bearings that pivotally support the rotating antenna 11. Radio waves are also radiated from the lower wall of the heating chamber symmetrically to the upper wall. Note that 15 is a pedestal on which the object to be heated placed in the dish 3 is placed.

Regarding the dimensions of the heating chamber, the width of the heating chamber is a, the depth is b, the number of odd modes in the width direction is m, the number of odd modes in the depth direction is n, the speed of light is c ₀ , and the oscillation frequency As f, (m/a) ² + (n/b) ² = (2f/c0
) If the heating chamber satisfies the dimensional relationship in ² , the mode in the heating chamber will be (mnO), and if the power supply from the high frequency generator is installed at the peak of this electric field distribution, the high frequency distribution in the heating chamber will be good. The patent was announced in 1972.
It was already clearly stated in the −24257 publication.

When the above mode is applied to the heating chamber shown in Figure 2,
The width is 406mm, the depth is 342mm, and the oscillation frequency is
If it is 2450MHz, there are (3, 5, 0) in the heating chamber.
mode appears. That is, as shown in FIG. 3, waves corresponding to three half wavelengths in the width direction and five waves in the depth direction are generated. In addition, the electric field distribution inside the heating chamber is good because the power feeding part (rotating antenna in Fig. 3) from the high-frequency generator is installed at a symmetrical position in the front, rear, left, and right at the peak of this wave (section A in Fig. 3). .

However, in the above-mentioned heating chamber, when the heated objects 16 and 17 are placed in upper and lower stages as shown in FIG. 2, the electric field strength between the upper and lower heated objects is disturbed. However, the lower part could not be heated properly when the upper part was heated. Furthermore, the pedestal 18
is a dielectric material such as glass or ceramics through which radio waves pass.

The present invention eliminates the above-mentioned disturbance of the electric field strength, and as shown in FIG. It was discovered that if placed between heated objects, the objects to be heated above and below can be heated extremely well. In other words, when cooking on the pedestal 18 with a conductive material, the distance from the rotating antenna section to the object to be heated affects the temperature of the object to be heated, as the distance is shorter for the lower object, the temperature rises faster, and the temperature difference between the upper and lower sides is It occurs, but
It has been found that when the conductor shown in FIG. 4 is placed between the objects to be heated, the temperature of the upper and lower objects to be heated increases almost uniformly. In addition, due to mutual interference between the upper and lower heated objects, that is, the influence of the upper heated object 17, the radio waves in the heating chamber are disturbed and the temperature rise of the lower heated objects becomes uneven. Thing 1
It has been found that due to the influence of No. 6, the temperature rise of the upper heated object 17 is no longer uniform.

FIG. 5 schematically shows the electric field distribution inside the heating chamber, as seen from the front of FIG. 3. FIG. 5a shows the state in which the conductor 19 of FIG. 4 is inserted, and when the conductor 19 is inserted, three half-wavelength standing waves are generated above and below the objects to be heated 16 and 17. Therefore, it is thought that an electric field is created in the objects to be heated 16 and 17 so that adjacent waves shoot each other, so that the objects to be heated can be cooked uniformly.

On the other hand, Fig. 5b shows the case where the object is placed on a glass plate, and as the electric field between the upper and lower heated objects 16 and 17 is disturbed, the electric field strength in the heated object becomes uneven and the cooking distribution performance deteriorates. It is also thought that the distance from the antenna had an effect.

Next, a method for putting the conductor 19 into practical use will be explained with reference to FIG. In the figure, the conductor 19 is glass,
It is embedded and integrally molded in a heat-resistant dielectric material 20 such as plastic to serve as a receiving tray for the upper heated object (FIG. 2, 17).

Further, by making it possible to place the conductor on a convex portion 22 formed on the heating chamber wall surface 21, and bringing the conductor end portion and the heating chamber wall close to each other, capacitive coupling is made more effective in terms of high frequency.

As is clear from the above explanation, by eliminating mutual interference between the upper and lower layers through two-stage cooking, it is possible to provide a high-frequency heating device with good cooking performance. It is possible to provide a high-frequency heating device that requires a smaller installation space compared to the required high-frequency heating device, and kitchen rooms of hotels, restaurants, etc. can be used effectively.

[Brief explanation of the drawing]

Figure 1 is a front cross-sectional view of a conventional high-frequency heating cooker.
FIG. 2 is a front cross-sectional view of a high-frequency heating cooker according to an embodiment of the present invention, FIG. 3 is a diagram showing the electric field mode 350, FIG. 4 is a diagram showing the conductor in the electric field mode 350, and FIG. Fig. 5a is a diagram schematically showing the electric field distribution in the heating chamber of the high-frequency heating cooker of the present invention, Fig. 5b is a diagram schematically showing the electric field distribution in the conventional heating chamber, and Fig. 6 is a diagram showing the electric field distribution in the heating chamber of the present invention. FIG. 2... Heating chamber, 5... Magnetron, 9... Waveguide, 10... Power feeding port, 11... Rotating antenna,
12... Partition plate.

Claims (1)

[Scope of Claims] 1. A heating chamber formed in a substantially rectangular parallelepiped shape within a main body, a door provided in a front opening of the heating chamber so as to be openable and closable, and a high-frequency generator that radiates high-frequency waves into the heating chamber. The width of the heating chamber is a, the depth is b, the number of odd modes in the width direction is m, the odd mode in the depth direction is n, the speed of light is c ₀ , and the oscillation frequency is f (m/a) ² + (n/b) ² = (2f/c ₀ ) As a heating chamber that satisfies the dimensional relationship of ² , a power feeding section from a high frequency generator is provided at the peak of the electric field mode on the top and bottom wall of the heating chamber. A high-frequency heating device characterized in that a table on which objects to be heated are placed is provided above and below a heating chamber, and a conductor is inserted between the upper and lower objects to be heated to connect the peaks of modes in the heating chamber. 2. The high-frequency heating device according to claim 1, wherein the conductor is inserted into a pedestal made of an upper dielectric material on which an object to be heated is placed. 3. The high-frequency heating device according to claim 1, wherein capacitive coupling is provided between an end of the conductor and a wall of the heating chamber.