JPS6012755B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radio wave seal for a high frequency heating device.
The purpose is to improve safety and to construct a device that is easy to use and more economical.

Various configurations have been proposed and put into practical use for radio wave seal configurations of high-frequency heating devices, such as those using choke attenuators and those using radio wave absorbers. The aim is to obtain a higher attenuation rate by using both. FIG. 1 is a schematic cross-sectional view of a high-frequency heating device according to the present invention. In Figure 1, heating chamber 1
A door 2 is provided in the opening □ on the front surface of the door 2 so that the door 2 can be opened and closed freely.
Radio waves are irradiated into the heating chamber 1 from a magnetron 3 provided in the heating chamber 1 to perform high-frequency heating. FIG. 2 shows an embodiment of the present invention through a partial sectional view in which only the radio wave seal portion of the high frequency heating device shown in FIG. 1 is enlarged. FIG. 3 is a partially cutaway perspective view of the same portion.

In FIGS. 2 and 3, a door 2 is provided opposite the opening periphery 4 of the heating chamber 1 so as to be openable and closable.

A door inner plate 5 is provided inside the door 2, and the door inner plate 5 and the opening peripheral edge 4 are in surface contact with each other when the door is closed. A choke groove 6 surrounded by the door 20 and the door inner plate 5 is formed in the periphery of the door 2. Near the entrance of the choke groove 6, a comb-shaped periodic structure 7 with grooves formed on a metal plate at equal intervals is fixed to the door 2 by welding or the like. The tip 8 of the periodic structure 7 has a U-shaped bent portion. According to the configuration according to the present invention, the radio waves inside the heating chamber 1 are transmitted to the opening periphery 4 when the door is closed.
The side surface of the door inner plate 5 reduces radio wave leakage to the outside.

Here, if the face plate is not completely zero or if the door is partially open, the radio waves cannot be completely blocked and the radio waves will proceed to the next choke groove 6, but the closed part of the choke groove 6 By appropriately selecting the shape and dimensions of the periodic structure 7 provided nearby in accordance with the frequency of the radio waves used, it is possible to restrict the radio waves in the x direction shown in FIG. If we consider that the radio wave toward the choke groove 6 travels in the direction in which the two-way components (×, Z) are combined, then the periodic structure 7 causes the
Since the choke groove 6 can select the optimal structure and dimensions for radio waves only in the Z direction, the damping effect of the choke groove 6 can be extremely high. Further, in order to effectively regulate the radio waves of the x-direction component, the periodic structure 7 must have an optimal shape and dimensions selected according to the radio waves used. In the case of a comb-shaped periodic structure, this is closely related to the width of the comb and the height of the column.

As described above, the length of the comb is determined by the frequency of the radio waves used, but since the periodic Z-period structure 7 of the present invention has a U-shaped bent portion at the tip 8, the actual length of the comb is determined by the frequency of the radio waves used. 1,1121
3, and the periodic structure 7 can be freely configured with an optimal dimension without increasing the thickness h of the door 2. This makes it possible to effectively regulate the radio waves in the x direction component, increasing the attenuation effect of the choke groove 6,
The amount of radio wave leakage can be kept to an extremely low value not only when the door is closed, but also when the door is half-open, resulting in a highly safe device. In addition, the thickness h and width W of the door 2 are shorter than the dimension 1 or 12 of the periodic 2 structure 7.
Since the size of the door 2 can be small, the device is compact as a whole and does not take up much space, and is easy to open and close, making it a user-friendly device.

In addition, since the periodic structure 72 facing the surrounding green 4 of the entrance part of the main body has its tip 8 bent, the end faces do not face each other but are in so-called face contact, so that the electric field is concentrated on the end face of the periodic structure 7.
There is no risk of sparks or heat generation between the periphery 4 of the closed portion and the closed portion 4.

Furthermore, the periodic structure 7 is composed of a conductor such as a metal plate 3
The comb-shaped part also serves as a heat sink for the door 2 to prevent temperature rise. Compared to the use of radio wave absorbers, etc., since it can be constructed entirely of metal, it is possible to realize a device that is highly heat resistant, inexpensive, and highly reliable, and can be used even in high-temperature atmospheres, making it possible to realize a wider range of applications. FIG. 4 shows a perspective view of another embodiment of the periodic structure according to the invention.

In FIG. 4, the tip 8' of the periodic structure 7' is bent into a U-shape, and a comb-shaped connecting portion 9 is provided. Even in such a shape, if the dimensions of the new bent part of the tip 8' are appropriately selected, not only can substantially the same regulating effect be obtained for radio waves in the x direction, but also the combs are connected by the connecting part 9. It is also strong and prevents deterioration of the radio wave attenuation effect due to deformation. Furthermore, deformation during processing is less likely to occur, making processing and assembly easier.

Although the choke groove 6 was explained using an example provided on the door side,
Needless to say, the effect is the same even if it is provided on the main body side. As described above, according to the present invention, it is possible to economically provide a high-frequency heating device that has a simple configuration, is safe with little radio wave leakage, and is compact and easy to use.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a high-frequency heating device showing an embodiment of the present invention, FIG. FIG. 4 is a partial perspective view showing another embodiment of the periodic structure of the high-frequency heating device according to the present invention. 2... Door, 5... Door inner plate, 6 ...Choke groove, 7 ... Periodic structure, 8 ... Tip, 9 ... Connection part. Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] 1. A door is provided at the opening of the heating chamber so as to be openable and closable, a chiyoke groove is formed in at least one of the periphery of the opening of the door and the heating chamber, and a tip of the groove is formed near the opening of the heating chamber. A high-frequency heating device characterized by having a comb-shaped periodic structure bent into a U-shape with the end faces facing inward. 2. A comb-shaped periodic structure having a U-shaped bent portion at its tip and a connecting portion at its base is provided near the opening of the chi-yoke groove. The high frequency heating device according to item 1.