JPS5844558Y2 - high frequency heater - Google Patents

Description

[Detailed description of the invention] This invention improves the drawbacks of so-called high-frequency heaters, improves heating efficiency by using heating by surface waves, and creates a safe and easy-to-use high-frequency heater that can be used in general households. This is what we provide.

The main purpose of the present invention is to improve heating efficiency by using surface wave heating.

Another object of the present invention is to make it possible to heat thick objects by using ordinary radio waves in combination.

Yet another object of the present invention is to provide a simple and easy-to-manufacture surface wave line suitable for heating.

Still another object of the present invention is to provide a simple structure that is highly safe and can be used in ordinary homes.

Surface waves in radio waves are also called slow waves, a name that indicates one wave form of radio waves.

This surface wave is used in microwave oscillators or microwave circuits by taking advantage of its characteristics.

There are two characteristics of surface waves:

(1) All surface waves exhibit an exponentially reactive decrease in the direction perpendicular to the transmission direction as they move away from the surface of the transmission system, and there is no power propagation or radiation in this direction.

That is, radio wave energy is concentrated on the surface of the surface wave line.

(2) Surface waves generally propagate at a phase velocity slower than the speed of light.

This is called a slow wave. A circuit that transmits surface waves with the above characteristics is called a surface wave line. (1) A dielectric board or multilayer board that satisfies certain conditions.

(ii) Metal protrusions called pleated lines (tooth-shaped circuits) are lined up periodically in the direction of radio wave propagation.

(iii) Conductive members arranged periodically in the direction of propagation of radio waves.

(Ladder type circuit) is generally known.

Now, when such surface waves are used to heat a dielectric material such as food or cloth, the radio wave energy is concentrated on the surface of the surface wave line, so if the object to be heated is placed near it, the radio wave energy will be concentrated on the surface of the surface wave line. Concentrates on objects and improves heating efficiency.

In addition, wave forms of radio waves other than the above-mentioned surface waves are referred to as normal radio waves for convenience.

Various ideas have been made in the past to use surface waves as described above for heating, but these conventional examples have the following major drawbacks.

(a) Only surface wave heating can be used.

In other words, since the structure is such that it emits normal radio waves, as shown in feature (1) of surface waves, the radio wave energy is concentrated on the surface of the line, so it can heat thick objects. In this case, energy does not penetrate sufficiently into the object to be heated, and only the surface wave line side of the object is heated.

Therefore, thin materials such as film are fine, but thick materials often used in home cooking, such as cakes, etc.
The drawback is that hamburgers and the like cannot be heated sufficiently.

(b) No measures have been taken to deal with many types of objects to be heated.

That is, all of these methods are limited to a single type of heated object, so they lack versatility.

(C) Not suitable for general households.

(i) There is no flexibility for multiple types of cooking and heating.

(ii) Since no heating chamber is provided, there is no countermeasure against the danger of the human body accidentally approaching the radio wave emission space.

(d) Surface wave lines are complex and difficult to make.

(e) The space in which the surface waves are excited and the space in which the heated object is placed are the same.

Particularly in tooth-shaped circuits, the energy that excites surface waves between the teeth is supplied through the space on the tip side of the teeth.

Since the objects to be heated are placed in the same space, there is a drawback that the excitation state of the surface waves naturally changes depending on the change in the object to be heated.

Therefore, the present invention solves the above-mentioned conventional drawbacks with a simple structure, and an embodiment thereof will be described below.

In Fig. 1, 1 is the door, 2 is the main body, 3 is the magnetron, 4 is the heating chamber, 5 is the object to be heated, 6 is the radio channel, 9 is the antenna of the magnetron, 10 is the bottom plate of the heating chamber, 11° 13
1 is a cover made of a dielectric material, and 14 is a surface wave line.

FIGS. 2 and 3 show an embodiment of the surface wave line 14 used in the present invention.

The surface wave line 14 is constructed by periodically punching out a plurality of slots 8 in the metal plate 7 in the left-right direction in the figure to form periodic discontinuities.

The length of the slot 8 is determined by taking into account its periodic width, the length of the metal plate, the gap provided below it (radio wave passage described later), and the dielectric cover provided integrally with it. This allows radio waves to be excited as surface waves.

Further, in the figure, the dielectric cover is removed for the sake of clarity, but in reality, it is disposed together with the dielectric cover in the heating chamber as shown at 11 in FIG.

By punching holes in the metal plate almost periodically in this way, periodic discontinuities are formed by the holes in the metal conductive part, and by integrating the holes with the dielectric cover, a useful surface wave line can be constructed. Can be done.

FIG. 4 shows an embodiment in which the hole 8 is further covered.

(The metal plate 7 with L8 punched out as shown in Figures 2 and 3 is integrally molded with resin, so that the resin is also filled into the hole 8, so there is no possibility of clogging due to dust etc.) do not.

In the above configuration, the radio waves emitted from the antenna 9 of the magmetron 3 are radiated as indicated by arrows 12 and 15 in FIG. 6, a surface wave is excited on the surface wave line 14 to heat the object 5.

Some of the radio waves 15 are directly coupled to the surface wave line 5 near the magnetron 3 and excited as the surface wave line, but in this case, the vicinity is extremely strongly excited and becomes a major cause of uneven heating.

Therefore, the radio wave path 6 needs to be designed to reduce this phenomenon as much as possible.

In this way, the object to be heated is heated by both surface waves and ordinary radio waves, so even if the object is thick, it will be sufficiently heated.

Therefore, the drawback (a) of the conventional example can be completely improved.

Also, since a part of the energy is concentrated on the surface of the surface wave line as surface waves, it is concentrated on the heated object placed on top of it, resulting in higher heating efficiency compared to ordinary microwave ovens that rely only on ordinary radio waves. This will lead to better use of energy.

These are made possible by providing a heating chamber as shown in FIG.

If there was no heating chamber, normal radio waves would be emitted into the space, creating a danger that people nearby would be exposed to radio wave radiation.

Therefore, the drawbacks (b) and (C) of the conventional example can also be improved.

In addition, a radio wave passage 6 is also provided, so there is a drawback (d).

(e) can also be improved.

Furthermore, the surface wave line used in this embodiment is easy to manufacture because it is only necessary to provide a dielectric cover on a flat plate made by sheet metal processing.

FIG. 5 shows another embodiment of the present invention, in which the radio wave passage 6 is formed by a partition wall 19 made of metal.

The surface wave line 14 consists of a metal conductor plate with holes 8 periodically made as shown in FIGS. 2 and 3, and a dielectric cover 11.
It is a combination of.

Radio waves from antenna 9 are radiated into the heating chamber as normal radio waves as indicated by arrow P.

In addition, the remaining radio waves pass through the radio wave path 6 as indicated by arrow Q and are heated from the surface wave line 14 to the object to be heated as surface waves.

As in this example, if the normal radio wave radiation port is provided on the opposite side of the surface wave line to the object to be heated, energy is supplied from above and below the object to be heated, so even thicker objects can be heated well. There is an advantage.

As explained above, according to the present invention, even a thick object to be heated can be heated, and a part of the energy can be actively concentrated on the object to be heated, which is extremely efficient.

Further, the surface wave line can also be used as a table for placing a heated object.

Furthermore, it is safe because it has a heating chamber and is extremely easy to use.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a high-frequency heater showing an embodiment of the present invention, FIG. 2 is a plan view of the main surface wave line in FIG. 1,
3 is a sectional view taken along the line A--A in FIG. 2, FIG. 4 is a sectional view of another embodiment of the intermediate portion, and FIG. 5 is a sectional view of another embodiment of the present invention. 1...Door, 2...Body, 3...
...Magnetron, 4...Heating chamber, 5...
... Heated object, 6 ... Radio wave path, 9 ...
・Antenna, 14...Surface wave line.

Claims (1)

[Scope of utility model registration request] A heating chamber made of a conductive material, a radio wave oscillator that supplies radio waves into the heating chamber, and periodic discontinuities made of multiple rows of holes are integrally formed on a single metal plate, and the surface is made of dielectric material. a surface wave line covered with a body, the surface wave line is arranged in the heating chamber with a substantially uniform gap from the bottom of the heating chamber, and the radio wave from the radio wave oscillation source is coupled to the surface wave line. and a high frequency heater in which a part of the radio waves from the radio wave oscillation source is directly coupled to the heating chamber.