JPS63178487A - Radio 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 high frequency heating devices such as electronic engines.

Conventional technology The method of introducing high frequency waves into the heating chamber of a high frequency heating device such as a microwave oven is generally to provide a substantially rectangular opening or notch in the wall, ceiling, or back wall of the heating chamber, and to Many waveguides are made by extending a series of rectangular cross-section metal-carved waveguides, and a high-frequency generating means such as a magnetron is attached to the extended end.

An example is shown in FIG.

In the configuration shown in the figure, a part of the side wall 2 of the heating chamber 1 is provided with an opening 3, a waveguide 4 leading to the opening 3 is integrally attached to the outside of the side wall 2, and a magnetron 5 is attached to one end of the waveguide 4. After installation, the antenna 6 of this magnetron 6 is inserted into the waveguide 4, and the high frequency waves generated from there are transmitted to the waveguide 4.
It is led from inside through the opening 3 into the heating chamber 1.

A cover 7 made of a material with a low dielectric constant is attached to the opening 3.

A rotary receiver 8 is provided on the bottom of the heating chamber 1 on which the object to be heated is placed, and is rotated by a rotary drive shaft 9. The rotational drive shaft 9 penetrates the bottom surface of the heating chamber and protrudes outward.
It is connected to the motor 1o.

When introducing high frequency waves into the heating chamber 1, by using the waveguide 4 as shown, it is relatively easy to adjust the position and size of the opening 3, or the shape, length, and cross-sectional dimensions of the waveguide 4. As a result, there is an advantage that the distribution of high frequencies within the heating chamber 1 can be made more uniform.

Normally, it is difficult to obtain ideal uniformity in the high frequency distribution within the heating chamber 1, and differences in strength appear due to uneven electric field concentration. At this time, in order to reduce uneven heating of the object to be heated as much as possible, it is desirable that the rotary receiver should create a strong electric field region approximately in the center of the table 8.

The size and amount of the object to be heated is left to the user's choice, but for small amounts or small objects, the heating time will be proportionally shorter, and in that case, the unevenness of the high frequency distribution will affect the heating of the object. Directly affects unevenness. The degree of influence is much higher than when heating large quantities or large items. Moreover, it is assumed that the frequency of heating small amounts and small objects to be heated is much higher. Therefore, in general, the receiver is required to have a relatively strong electric field near the center of the bottom surface of the stand 8. The location in the heating chamber where the electric field is concentrated is determined by the size of the heating chamber, the presence or absence of irregularities, and the method of power supply, but the waveguide method described above is the most advantageous when designing it. It is considered to be a method.

Problems to be Solved by the Invention However, the use of the waveguide system causes the following problems.

(1) It is necessary to newly manufacture the waveguide itself separately from the heating chamber and install it on the wall or ceiling of the heating chamber, and the installation must be done carefully to avoid high frequency leakage. Yes, therefore the manufacturing cost is high.

(2) It is necessary to further install a high-frequency generating means such as a magnetron outside the waveguide, and the installation position is far from the opening, so installation work cannot be done from inside the heating chamber or from the opening. Therefore, parts such as metal fittings, screws, and NANDs for attachment must be prepared in advance on or near the waveguide, which increases manufacturing costs and labor.

(3) When the heating chamber is painted and used, the inside of the waveguide becomes a dead end where cleaning water for degreasing before painting tends to be insufficiently discharged.
It is necessary to perform configuration.

Means for Solving the Problems The present invention eliminates all of the above-mentioned conventional drawbacks by providing a relatively large quadrilateral opening in a part of the side wall of the heating chamber, and attaching a box-shaped metal part to the outside of the opening. Alternatively, a part of the side wall of the heating chamber is formed by drawing so as to bulge outward, a high frequency generator such as a magnetron is attached to this from the outside, and then a part of the side wall of the heating chamber is formed so as to bulge out. A thin plate-like cover made of a material with a low dielectric constant is attached to the opening so as to be flat, and a metal film is attached to a part of the back surface of the cover.

The material for this cover can be a resin plate, glass plate, mica plate, etc., and the metal film can be pasted or vapor-deposited with foil or film of aluminum, copper, iron, etc.

Produced by partial plating, etc.

The metal film is formed uniformly over the entire surface of the back surface of the cover, leaving out, for example, a portion of the bottom or top, and the metal film is attached so that the portion where the film is not formed faces one end of the opening in the side wall of the heating chamber.

Function: Since there is no metal film on a part of the cover, the high frequency waves from a high frequency generator such as a magnetron pass through the space between the metal wall of the bulge and the metal film on the back of the cover. part into the heating chamber.

By making the cover material a thin plate with a low dielectric constant,
High frequencies pass through this unless reflected by the metal film.

This is based on the same logic as in the case of introducing high frequency waves into the heating chamber through the cover provided on the waveguide opening, which was explained in the related art.

The space between the bulge provided on the side wall of the heating chamber and the metal film on the back of the cover functions in the same way as a waveguide, and can be configured to provide a more appropriate distribution of high frequencies within the heating chamber.

Example Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, the heating chamber 11 has a top surface 12. Side 13.
The bottom surface 14 and, although not shown, the back wall surface.

The back of the door is surrounded by a metal plate. A square notch 16 is provided in a part of the right side surface 132L of the heating chamber, and a box-shaped magnetron mounting plate 16 is attached so as to cover this from the outside.

The magnetron mounting plate 16 is fixed to the right side surface 13a of the heating chamber by spot welding, caulking, or the like.

The magnetron 17 is attached to the bottom surface of the magnetron mounting plate 16 with screws 18 or the like, and the magnetron antenna 172Li protrudes inward from the magnetron mounting plate 16. The depth of the magnetron mounting plate 16 is the antenna 1.
It is deeper than the length of 72L.

A cover 19 covers the side surface 13a so as to cover the notch 15.
It is fixed with screws from inside the heating chamber.

The cover 19 is made of a synthetic resin plate with a low dielectric constant, and aluminum foil 2o is partially attached to the back surface of the cover 19.

The guide bar 19 may be made of heat-resistant glass, mica, or the like in addition to synthetic resin.

The part where the aluminum foil 20 is not pasted is the cutout 1
The heating chamber 11 is supplied with high-frequency waves through the heating chamber 11.

Although an example has been described in which aluminum foil 20 is used as the metal film, films other than such metal foil can also be formed by metal vapor deposition, plating, etc.

The metal film 20 needs to have electrical continuity with the inner wall of the heating chamber 11, and therefore this embodiment cannot be applied when the heating chamber wall surface has an electrically insulating coating such as paint. Of course, electrical continuity can be obtained by masking and painting the area around the opening, but the painting process is time-consuming.

Figure 2 shows a solution to this drawback, and shows the heating chamber wall 13&
The notch opening 16 is sandwiched between the magnetron mounting plate 16 and the opening cover 21 to be mounted and fixed. Work on screws, etc. for installation from inside the heating chamber. At this time, the metal film 22 generated on the back surface of the opening cover 21 is
As shown in the figure, there is also a screw hole 23, and the screw is inserted through the screw hole of the opening cover 21, breaks through the metal membrane 22, completely penetrates the heating chamber wall surface 131L, and is fixed to the magnetron mounting plate 16. The torn portion of the metal film 22 reaches the magnetron mounting plate 16 and electrical continuity therewith is established.

FIG. 4 shows the heating chamber wall surface bulged outward by drawing processing.

Since the magnetron mounting plate 24 and the heating chamber wall surface 25 are integrally formed, there is no fear that radio waves will leak outside through the gap.

The portion 27aFi without the metal film of the opening cover 27 to which the metal film 26 is pasted is always in contact with one of the four sides of the opening 25& of the heating chamber wall surface 25, but the portion 27& without the metal film is 6 Opening cover 27 as shown in Figure 6
The opening 262
By attaching it so that it matches the top and bottom ends of L,
There are two high-frequency introduction ports into the heating chamber, which is effective in making the high-frequency distribution uniform.

Effect of the invention As described above, according to the present invention, the following effects can be obtained.

(1) By cutting out a part of the side wall of the heating chamber and attaching a box-shaped magnetron mounting plate, or by drawing it so that it bulges to the outside of the side of the heating chamber,
Furthermore, when attaching a high-frequency generator such as a magnetron to the outside, the attachment can be done from the inside of the heating chamber with screws, etc., and there is no need to prepare extra metal fittings or special nuts in advance, making the work easy.

(2) By attaching an aperture cover made of a low dielectric constant material with a metal film partially attached to its back surface to cover the aperture provided on the side of the heating chamber, it can function in the same way as a waveguide. By adjusting the size of the metal film when it is generated, the distribution of high-frequency waves inside the heating chamber can be made even. (3) When painting the heating chamber, it is also possible to prevent the discharge of cleaning liquid before painting. No special means are required.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a high-frequency heating device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a second embodiment of the present invention, FIG. 3 is a cross-sectional view of the same essential parts, and FIG. 5th sectional view of the third embodiment of
The figure is a sectional view of the same essential part, and FIG. 6 is a sectional view of a conventional example. 11...Heating chamber, 12...Top (heating chamber), 13...Heating chamber side, 14...Bottom, 16... Notch, 16... Magnetron mounting plate, 19... Cover, 20...
...Metal foil, 21...Opening cover, 22...
...Metal film. Name of agent: Patent attorney Toshio Nakao and one other person] Figure 3 @ Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) A box-shaped protrusion that bulges out of the opening provided in the side wall of the heating chamber is provided, a high-frequency generator such as a magnetron is attached to this, and the opening of the box-shaped protrusion is covered and the inner surface of the side wall of the heating chamber is connected. A high-frequency heating device configured to provide an aperture cover made of a material with a low dielectric constant so as to form a uniform plane, and partially cover the back surface of the aperture cover with a metal film. (2) Consists of a box-shaped mounting plate for a high-frequency generator such as a magnetron that covers an opening provided in the side wall of the heating chamber from the outside, and an opening cover that covers the opening from the inside, and is designed to pierce the metal film on the back side of the opening cover. 2. The high-frequency heating device according to claim 1, wherein the opening cover and the box-shaped mounting plate are screwed together from within the heating chamber, with the heating chamber side wall interposed therebetween. (3) The high-frequency heating device according to claim 1, wherein at least one side of the quadrilateral opening provided in the side wall of the heating chamber overlaps a portion of the back surface of the opening cover where there is no metal film.