JPH02155200A - High frequency heating apparatus - Google Patents

Abstract

PURPOSE:To efficiently cool a microwave oven, lessen high-frequency loss thereof and obtain mechanical strength thereof endurable against electromagnetic force by employing a material with low electric conductivity as a short edge side-member forming a waveguide and a material with high electric conductivity as a long edge side-member forming thereof and joining the members to each other. CONSTITUTION:A material with high electric conductivity is employed as a long edge side-member 10 of a rectangular waveguide. And also a material with low electric conductivity is employed as a short edge side-member 11 thereof. A joining portion 12 where the members are to be joined to each other is diffused in solid phase to form the waveguide. Since the material with high electric conductivity is employed as the long edge side-member 10 of the rectangular waveguide, thermal conductivity is improved, quantity of heat passing through the waveguide becomes large and cooling effect is improved. Moreover, high-frequency loss and Joule loss are lessened. This leads to less heat generation. On the other hand, because of employing the material with low electric conductivity as the short edge side-member 11, an eddy current, which is to be induced when plasm is disappeared, is lessened and electromagnetic force operating by magnetic field is also lessened. Therefore, such as supporting configuration of the waveguide is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high-frequency heating device for plasma heating in a nuclear fusion (experimental) device, etc., and particularly relates to a low-frequency hybrid wave band high-frequency heating device.

(Prior art) Plasma heating in nuclear fusion (experimental) equipment is performed by Joule heating, which heats the plasma by passing an electric current through it, and by neutral particle heating, high-frequency heating, etc. as a second-stage heating method. . Here, the high-frequency heating method is a method of increasing the temperature of the plasma by absorbing the energy of high-frequency electromagnetic waves into the plasma.There are various methods depending on the frequency used, one of which is a low-frequency hybrid wave band high-frequency heating device. be. One example is shown in FIG.

That is, as shown in FIG. 6, this high-frequency heating device includes a high-frequency oscillator 1 that generates and amplifies high-power electromagnetic waves;
Each fusion of electromagnetic waves generated by this high frequency oscillator 1 (experiment)
High frequency transmission system 3 that transmits to device 2 and this transmission system 3
It consists of a high frequency coupling system 5 which emits electromagnetic waves to plasma 4 from its terminal.

In this case, the high-frequency coupling system 5 is inserted particularly through the port 2a of the nuclear fusion (experimental) device 2, so dimensional restrictions are severe and it is provided in a narrow space.

FIG. 7 shows a more detailed configuration of this high frequency coupling system 5. In FIG. 7, reference numeral 6 denotes a rectangular waveguide, and a plurality of waveguides 6 are usually arranged in a grid pattern. Electromagnetic waves are transmitted through each waveguide 6 and emitted into the plasma 4. These waveguides 6 are entirely covered by a waveguide bundle container 7. Further, the waveguide bundle container 7 is provided with a cooling passage 8, and a refrigerant such as gas is allowed to flow through the passage 8, so that the waveguide bundle container 7 and the waveguide 6 can be cooled. Further, a connection waveguide 9 is connected to the rear end of the coupling system 5, and is connected to the transmission system 3.

(Problem to be Solved by the Invention) By the way, each of the waveguides 6 constituting the high-frequency coupling system 5 described above has a smaller gap between adjacent waveguides 6 on the plasma front end side, so that the plasma 4 can be absorbed more easily. In order to efficiently inject electromagnetic waves, it is desirable to narrow the pitch between the waveguides 6.

On the other hand, in order to inject electromagnetic waves into the plasma so as to satisfy the nuclear fusion conditions, the output of the electromagnetic waves must be increased, but high-frequency loss is also increasing.

In this case, if the incident heat from the plasma 4 is also considered, it is becoming difficult to cool the waveguide 6. Normally, the waveguides 6 are made of stainless steel, and their thermal conductivity is low. A sufficient cooling effect could not be obtained by air-cooling the waveguide 6, and the temperature of the waveguide 6 could reach several hundred degrees. Therefore, the thermal stress generated in the waveguide 6 also increases, which poses a problem in terms of mechanical strength.

Furthermore, recently, in order to efficiently inject electromagnetic waves, it has been considered to make the long sides of the rectangular waveguides 6 closely adhered in a horizontal line, but in this case, it becomes difficult to cool the waveguides 6.

The present invention has been made in view of the above circumstances, and its purpose is to efficiently cool a waveguide bundle in the low hybrid waveband, reduce high frequency loss, and have a simple structure that can withstand electromagnetic force. The object of the present invention is to provide a high-frequency heating device that can secure strength and perform plasma heating with high output and high efficiency.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides a high-frequency heating device equipped with a high-frequency coupling system configured by arranging a plurality of rectangular waveguides. , the short side members forming each of the waveguides are made of a material of low conductivity (ζ), and the long side members are made of a material of high conductivity and are in contact with each other.

(Function) In a high-frequency heating device with such a configuration, a high conductivity material is used for the long side members of the rectangular waveguide, so the thermal conductivity is high and the amount of heat passing through is high. This can improve cooling efficiency. Furthermore, since high-conductivity materials have less high-frequency loss and Joule loss, the amount of heat generated can be reduced accordingly.

On the other hand, since a low conductivity material is used for the short side members of the rectangular waveguide, the eddy current induced during plasma extinction is small, and the electromagnetic force exerted by the magnetic field is also small. This makes it possible to simplify the process.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show an example of the basic configuration of a waveguide of a high-frequency heating device according to the present invention. As shown in FIGS. 1 and 2, a high conductivity material such as copper is used as the long side member 10 of the rectangular waveguide, and a low conductivity material such as stainless steel is used as the short side member 11. The waveguide is constructed by solid-phase diffusion bonding the bonding portions 12 of these members to each other as shown in the figure. Then, in order to facilitate the flow of high frequency current to the surface layer of the short side member 11, which serves as an electromagnetic wave path, a thin film 13 made of a highly conductive material is formed.

This thin film 13 may be formed by press-bonding copper foil or silver foil, or may be formed by copper plating, silver plating, or the like.

FIG. 3 shows an example of a case where a plurality of waveguides configured as described above are joined together in a horizontal line.

That is, in FIG. 3, when a plurality of waveguides are arranged horizontally in a row, the long side members 10 of the adjacent waveguides are made common, and they are sequentially joined as in FIGS. 1 and 2. As a result, each waveguide is constructed integrally.

In addition, Fig. 4 shows the waveguide group configured as shown in Fig. 3 above.
An example of the configuration is shown when stacked in the lower two tiers.

In such a configuration, the short side member 11 at the overlapping portion of the upper waveguide group and the lower waveguide group can be made common.

Therefore, according to this embodiment, since the long side portion 4i0 of the rectangular waveguide is made of a high conductivity material with high thermal conductivity and a large amount of heat passing through, the cooling efficiency can be increased. Moreover, loss due to Joule heat during high frequency generation can be reduced.

Furthermore, since the short side member 11 of the rectangular waveguide is made of a low conductivity material, and the thin film 13 made of a high conductivity material is formed on the surface layer that serves as an electromagnetic wave path, high frequency current can easily flow. In addition, as shown in Fig. 4, the eddy current I induced when the plasma disappears is small, and the electromagnetic force F exerted by the magnetic field BT is also small. can be secured.

Furthermore, since both the long side member 10 and the short side member 11 are in-phase diffusion bonded to form a rectangular waveguide, it is more accurate and economical than a waveguide formed by joining such as welding. It can be manufactured. In particular, if a plurality of waveguides are arranged horizontally in a row and configured integrally as shown in FIG. 3, it becomes possible to share the long sides 4a of adjacent waveguides, As shown in Figure 4, if the upper and lower layers are overlapped to form an integral structure, it becomes possible to share the short side members of the overlapped part, making it more economical, compact and easy. A waveguide bundle can be constructed.

FIG. 5 shows another embodiment of the present invention, in which the same parts as in FIG. 1 are given the same symbols, and only the different points will be described here. That is, in this embodiment, a plurality of cooling holes 14 are provided in the short side member 11 constituting the rectangular waveguide in the same direction as the electromagnetic wave path.

With such a configuration, by flowing the cooling medium directly into the cooling holes 14, the cooling effect can be enhanced, and a high-output waveguide can be obtained.

In the above embodiment, a case has been described in which a plurality of cooling holes 14 are provided in the short side member 11, but the cooling holes 14 may be provided in the long side member 10, and the cooling holes 14 may be provided in the long side member 10. It may be provided on both sides of the member.

[Effects of the Invention] As described above, according to the present invention, it is possible to efficiently cool the waveguide bundle in the low hybrid waveband, have little high frequency loss, and have a simple structure with mechanical strength that can withstand electromagnetic force. This makes it possible to provide a high-frequency heating device capable of plasma heating with high output and high efficiency.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a perspective view showing the basic configuration of a waveguide in a high-frequency heating device according to the present invention, FIG. 2 is an enlarged view of section A in FIG. 1, and FIG. FIG. 4 is a perspective view showing a configuration example of a waveguide bundle different from that in FIG. 3; FIG. 5 is a perspective view showing a waveguide bundle in another embodiment of the invention. FIG. 6 is a perspective view showing a tube, FIG. 6 is a configuration diagram showing an example of a conventional high frequency heating device, and FIG. 7 is a sectional view showing a detailed configuration of the high frequency coupling system in FIG. 6. 10... Long side member, 11... Short side member, 12... Solid phase diffusion bonding part, 13...
...thin film,]4...cooling hole. Applicant's agent Patent attorney Takehiko Suzue] 1 Figure 4 Figure 4

Claims (1)

[Claims] In a high-frequency heating device equipped with a high-frequency coupling system configured by arranging a plurality of rectangular waveguides, the short side members forming each waveguide are made of a material with low conductivity, and the long side members are made of a material with low conductivity. A high-frequency heating device characterized in that the members are made of a material with high conductivity and the two are joined together.