JPS5923435B2 - Door in high frequency heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to prevent leakage of radio waves from a gap between an opening edge of a heating chamber of a high-frequency heating device and a door.

Conventionally, it has always been necessary to prevent leakage of radio waves from high-frequency heating devices. For this reason, the following three means have been used alone or in combination.

That is, the first method is to make complete metal contact between the peripheral edge of the door and the edge of the opening of the heating chamber of the high-frequency heating device. Although it must be machined flat, it is actually impossible to obtain perfect metal contact between the door and the edge of the opening because there are large variations not only in sheet metal processing but also in assembly accuracy. It was common for a considerable amount of radio wave leakage to be observed.

The second method is to make the peripheral edge of the door have a choke structure, but even with this method, a considerable amount of radio wave leakage is observed.

Further, even if both are used together, it is impossible to completely prevent radio wave leakage.

The third method is to attach a radio wave absorbing material made of ferrite rubber or the like to the periphery of the door, but this radio wave absorbing material is not only extremely expensive, but is also suitable for heating rooms such as open ranges. The electrical and mechanical properties deteriorate due to the temperature rise during operation of the high-frequency heating device, which generates high temperatures, and furthermore, there are disadvantages such as it is extremely difficult to attach the radio wave absorbing material to a metal plate. .

(Fig. 1 shows a conventional example in which the first means, the second means, and the third means are used together)) The radio waves radiated into the heating chamber 1 from the high frequency oscillator are transmitted to the opening end of the heating chamber 1. It is attenuated by the metal contact formed by the edge 2 and the sealer plate 6 having a length of approximately 1/4 wavelength of the radio wave, and then the choke is formed by the recess 4 formed in the door body 3 and the sealer plate 6. The radio waves are attenuated by the outermost inner surface of the recess 4, and the radio waves are further absorbed by the radio wave absorbing material T attached to the outermost inner surface of the recess 4, thereby preventing the radio waves from leaking to the outside.

In this embodiment, a radio wave absorbing material is indispensable, and since the radio wave absorbing material has the drawbacks mentioned above, it not only shortens the life of the door itself, but also makes it difficult to manufacture. is still not resolved. The present invention
The above-mentioned drawbacks are solved by adding claw-shaped metal pieces to the periphery of the door.

Hereinafter, the door of the present invention will be explained in detail with reference to an attached embodiment. FIG. 2 is an enlarged perspective view of the main part of the door of the present invention, in which a metal door body 3 has a transparent radio wave shielding plate 8 fixed to it so as to cover an opening 3' provided in the center, and is heated by high-frequency heating. A recess 4 that opens toward the device body side is provided, and a sealer plate 6 of a predetermined length is provided on the side surface of the door body 3 facing the high-frequency heating device so that its outer end faces the opening of the recess 4 to form a chiyoke portion. , the inner wall surface 5 of the recess 4 is perpendicular to the radio wave leakage path 9 (indicated by arrows A+B) between the opening edge 2 of the heating chamber 1 of the main body of the high-frequency heating device and the sealer plate 6. The upper end of the inner wall surface 5 is bent at a right angle to cover the recess 4 to form a triangular claw-like member 10 made of metal and having a rounded tip.
, 10... are formed at predetermined intervals on the entire outer peripheral edge of the door body.

The claw-like bodies 10, 10, . . . may be formed by welding a separate metal plate 11 shown in FIG. 3 to the inner wall surface 5 of the recess 4 of the door body 3. Next, we will show the experimental results.

The length of the opening edge 2 and the sealer plate 6 facing each other is 20mj, the gap between the two is 2n1, the depth of the recess 4 is 20n1, the width is 54111, and the opening of the recess 4 covered by the sealer plate 6 is A door with a width of 24n is used, the gap between the outer periphery of the door and the outer periphery of the high-frequency heating device is 2m1, and the output of the high-frequency oscillator is 5.
00W, and with a beaker containing 275 cc of water placed in the heating chamber 1, claw-like bodies 10, 10, etc. as shown in FIG. In the case where there is no such thing, the power density of the radio waves leaking through the radio wave leakage path 9 at the outer peripheral edge of the door was 1.7 mw/ml to 1.0 mw/d.

ΣOn the other hand, when the claw-like bodies 10, 10... are formed as shown in FIG. Under these conditions, the power density of the radio waves leaking was 0.2 mw/Crll or less (at the entire outer periphery of the door).

The door of the present invention constructed as described above has the following effects.
Since periodic claw-like metal parts are formed on the first yoke, the effect of preventing radio wave leakage can be significantly enhanced.

Since only a claw-shaped metal plate is used for the second yoke and no radio wave absorbing material is used, manufacturing is easy and inexpensive.

3. Furthermore, since it is only necessary to bend and form the inner wall surface 5 itself, there is no need to weld the metal plates, and the manufacture is simple.

4.Since the radio wave leakage prevention effect is extremely high, the gap between the opening edge of the heating chamber and the sealer plate can be slightly widened, and therefore the manufacturing and assembly precision can be low, making it easy and inexpensive. A door is made.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view showing a yoke portion of a conventional high-frequency heating device. FIG. 2 is an enlarged perspective view showing the main parts of the door of the present invention, and FIG. 3 is a perspective view showing one embodiment of a metal plate forming a claw-like body. DESCRIPTION OF SYMBOLS 1... Heating chamber, 2... Opening edge, 3... Door body, 4... Recess, 5... Inner wall surface, 6... Sealer plate,
9...Radio wave leakage path, 10...Claw-shaped body.

Claims (1)

[Claims] 1. On the door provided on the high-frequency heating device main body so that it can be opened and closed, a triangular claw with a rounded metal tip should be installed so as to protrude in a direction parallel to the radio wave leakage path formed between the high-frequency heating device main body and the door. A door in a high-frequency heating device, characterized in that shaped bodies are provided at predetermined intervals around the periphery of the door.