JPS6244396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device that heats foods by irradiating high-frequency waves to foods, and particularly relates to a uniform heating configuration in a center feeding system.

In a conventional high-frequency heating apparatus of this kind shown in FIGS. 1 and 2, for example, an object to be heated 3 such as food is placed on a bottom wall surface 2 in a heating chamber 1. A plate holder 4 is provided in a detachable manner.

High frequency waves are fed into the heating chamber 1 from a magnetron 5 through a waveguide 6, and the radio waves are stirred by stirrer blades 7 in order to reduce the difference in strength of the electric field pattern generated within the heating chamber 1. . The partition plate 8 is made of a material that does not easily absorb high frequencies, such as silicon-impregnated glass, and isolates the stirrer blade 7 and the object 3 to be heated. In FIG. 2, the wind generated by the cooling fan 9 that cools the magnetron 5 and other electrical components enters the heating chamber 1 through the inflow opening 10 provided on the wall of the heating chamber 1.
After rotating the stirrer blades 7, the air is discharged out of the apparatus through an exhaust opening 11 provided on the wall of the heating chamber 1.

The stirrer blades 7 stir the high-frequency radio waves in the heating chamber 1, but depending on the size and shape of the object 3 to be heated, it may be locally overheated or underheated. So-called uneven heating occurred. In other words, when there is no object to be heated or when the object to be heated 3 is extremely small, there is little difference in the strength of the electric field pattern, and therefore there is little uneven heating, but the object to be heated 3
The larger the surface area, or the larger and thinner the plane area, the greater the heating unevenness due to the strength of the electric field pattern. This heating unevenness has not been fundamentally elucidated, and at present no common configuration for eliminating this heating unevenness has been found for any type of high-frequency heating device. However, it is considered that the main factors contributing to the uneven heating are the dimensions and shape of the heating chamber 1, the shape of the power supply port 12 of the waveguide 6, the shape of the bottom wall surface 2 of the heating chamber 1, and the like. Therefore, as a structure for eliminating this heating unevenness, it is generally considered that the electric field pattern is changed by drawing the wall surface of the heating chamber 1, particularly the bottom wall surface 2, into a certain shape. As an example of this configuration, the bottom wall surface 2 has a dimension H as shown in FIG.
A space is provided in the lower part of the bottom of the plate holder 4 by drawing. In this example, due to the electric field pattern, the effect is essentially the same as if the object to be heated 3 on the plate pedestal 4 were suspended in the air, and the high-frequency radio waves also wrap around the lower center of the plate holder 4, uniformly covering the object 3 to be heated. It is known that high-frequency radio waves can be irradiated to However, with this configuration, when it comes to tall objects to be heated, such as beans or potatoes, only the bottom part of the object is heated, making it difficult to heat the top. Frozen shrimp, etc., had the disadvantage that only the center part was heated.

In other words, in the case of the configuration shown in FIG. 3, the electric field is concentrated at the lower central portion of the tray holder 4, and depending on the type of the object to be heated 3, uneven heating as described above occurs.

The present invention aims to eliminate the above-mentioned conventional drawbacks.

The present invention has a configuration in which a protrusion that protrudes toward the pan holder side is formed in the center of the bottom wall of the heating chamber, so that the electric field strength on the bottom surface of the pan holder can be made uniform, and heating can be achieved depending on the shape, size, etc. of the object to be heated. This eliminates unevenness.

An embodiment of the present invention will be described below based on the drawings.

In FIGS. 4 and 5, a center feeding type high frequency heating device is shown. High-frequency radio waves are supplied from the magnetron 5 through the waveguide 6 into the heating chamber 1 from the power supply port 12 while being stirred by the stirrer blades 7 . The power supply port 12 is located substantially coaxially with the center of the heating chamber 1. The bottom wall surface 2 of the heating chamber 1 is a plate holder 4
A pedestal portion 13 on which the holder is placed is formed at the outer peripheral edge along the side wall surface. In addition, in the center of the heating chamber 1, a protrusion 14 with a diameter φd is placed at a distance l ₁ from the bottom of the dish holder 4.
It is integrally molded on the bottom wall surface 2 of the heating chamber 1. Further, between this protruding portion 14 and the pedestal portion 13, a tray holder 4 is provided.
A recessed portion 15 is formed at a distance l ₂ . said distance
l ₁ is smaller than l ₂ . The diameter φ
In this embodiment, d is approximately 1/3 of the width L of the heating chamber 1.
I'm in moderation. Strictly speaking, it is most desirable to determine the diameter φd experimentally depending on the type of the object to be heated 3 and the size and shape of the heating chamber 1, but in reality, it is a reasonable value based on sponge cake, etc. Select.

Further, as shown in FIG. 5 of this embodiment, it is not necessary to limit the shape to a circle, and it may be a square shape.

In the above configuration, the high frequency supplied from the power supply port 12 is transmitted through the partition plate 8 and directly absorbed by the object to be heated 3, or is reflected on the wall surface of the heating chamber 1 and then absorbed by the object to be heated 3. There are things like that.

In particular, since the bottom wall surface 2 is formed with a height difference between the protruding part 14 and the recessed part 15, the high frequency is not concentrated in the center part of the dish pedestal 4 corresponding to the protruding part 14, and the high frequency is uniformly applied to the heated object 3. It is possible to irradiate.

Therefore, uneven heating due to the type and shape of the heated object 3 is reduced, and in particular, the bottom part of a tall object will not be overheated, and the central part of a flat and large object will not be overheated. I was able to resolve the issue. The reason for this is
The protrusion 14 changes the reflection of radio waves inside the heating chamber 1, especially on the bottom of the heating chamber, so that when the object to be heated 3 is placed on the pan holder 4, the "strong" part of the electric field pattern is It is thought that by moving to a higher position than the center of the table 4, the concentration of high frequencies in the center is reduced and is averaged over the entire lower surface of the tray holder 4.

As described above, by changing the shape of the bottom wall surface of the heating chamber, the present invention averages the electric field strength at the bottom of the dish holder and reduces uneven heating due to the type, size, shape, etc. of the object to be heated. It is possible to provide a high-frequency heating device with an excellent finish. Furthermore, by changing the height and position of the protruding part in accordance with the shape and dimensions of the heating chamber, it can be adapted to high-frequency heating devices of various capacities, and the simple structure allows cooking without adding new parts. This has effects such as improved performance. Moreover, the protrusion can be integrally formed on the bottom surface of the heating chamber, which provides excellent productivity, and since the protrusion does not move, a stable effect can be obtained.

[Brief explanation of the drawing]

Figure 1 is a front sectional view of a conventional high-frequency heating device.
Fig. 2 is a cutaway plan view of the same part, Fig. 3 is a front cross-sectional view of another conventional high-frequency heating device, and Fig. 4 is a cutaway plan view of the same part.
The figure is a front cross-sectional view of a high-frequency heating device according to an embodiment of the present invention, and FIG. 5 is a partially cutaway plan view of the bottom wall of the heating chamber. 1...Heating chamber, 2...Bottom wall surface, 3...Object to be heated, 4...Dish pedestal, 5...Magnetron, 7...
Stirrer blade, 12... Power supply port, 13... Pedestal part, 14... Protrusion part, 15... Recessed part.

Claims (1)

[Scope of Claims] 1. A heating chamber for storing an object to be heated, a dish pedestal on the bottom of the heating chamber on which the object to be heated is placed, a magnetron for feeding high-frequency radio waves into the heating chamber; A stirrer blade for stirring high-frequency radio waves from a magnetron is provided, and a protrusion close to the dish pedestal is provided at approximately the center of the bottom wall surface of the heating chamber located below the dish pedestal, and also holds the dish pedestal. The high-frequency heating device has a configuration in which a pedestal portion is provided on the periphery of the bottom wall surface, and the protrusion portion is integrally molded on the bottom wall surface of the heating chamber. 2. The high-frequency heating device according to claim 1, wherein the center line of the heating chamber and the center lines of the stirrer blades and the protrusion are substantially coaxial.