JPS5810714B2 - Vacuum vessel for plasma equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum vessel for a plasma device, and more particularly to a vacuum vessel for a plasma device in which wall sections of the vacuum vessel are connected by a flange.

A vacuum container for critical plasma mounting, etc. is installed in a toroidal coil in a donut shape, and the structure is generally such that the vacuum container can be brought into the toroidal coil in a disassembled state and then assembled. be.

Conventionally, in order to facilitate the assembly and disassembly of a vacuum vessel, the vacuum vessel was constructed by dividing it into a plurality of vessel wall sections in the circumferential direction, and the flanges provided at both ends of each vessel wall section were connected with bolts. Assembling a vacuum container.

FIGS. 1 and 2 are cross-sectional views showing the flange portion of the wall of a vacuum container having a flange as described above.

In FIG. 1, wall sections 1 and 2 of the vacuum vessel are shown in cross section in the thickness direction, with the upper part of the figure being the inside of the vacuum vessel and the lower part being the outside.

At the outer ends of the vessel wall sections 1 and 2 are flanges 3, respectively.
and 4 are provided.

The flanges 3 and 4 extend approximately at right angles to the wall sections 1 and 2 and have holes 7 and 8 for passing bolts 5 and tightening them by nuts 6.

The inner ends of the vessel wall sections 1 and 2 are formed with shoulders 9 and 10 which form a groove 11 when the vessel wall sections 1 and 2 are placed in the assembled position.

A sealing device 12 is provided in the groove 11 and is welded to the vessel wall sections 1 and 2 at both edges to hermetically seal the vessel wall sections 1 and 2.

Fig. 2 differs from the outer flange in Fig. 1 in that the flanges 3 and 4 are provided inside the vacuum vessel (at the top in the figure), so that the sealing device 12 is sandwiched between the flanges 3 and 4. It differs from the model, but has a similar configuration in other respects.

The conventional flange-type vacuum vessel for a plasma device as described above has a problem because the flange protrudes.

In the case of the outer flange type shown in Fig. 1, the space for extending the flange and the space required for assembly work are extremely limited due to the toroidal coil etc. placed near the periphery of the vacuum vessel. In the case of the inner flange type shown in the figure, there is no problem with the space outside the vacuum container, but the plasma volume inside the vacuum container becomes small, which is not preferable in terms of design.

In order to eliminate the above-mentioned disadvantages of vacuum vessels using flanges, it is also common practice to assemble the vacuum vessel by directly welding the multiple wall sections to each other.In this case, the space inside and outside the vacuum vessel is limited. There is no problem with it.

However, it is often necessary to disassemble and reassemble a vacuum container assembled by welding, and cutting and welding must be repeated each time.

Therefore, each time the vacuum container is assembled and disassembled, the length of the wall section of the vacuum container is reduced by the length of the cut, and at the same time, due to repeated heating, the properties of the material deteriorate and become unusable within a relatively short period of time.

Therefore, it is an object of the present invention to provide a vacuum for plasma equipment that eliminates the drawbacks of the conventional vacuum container for plasma equipment as described above, makes effective use of the space inside and outside the walls of the vacuum container, and does not shorten the service life due to assembly and disassembly. It is to provide a container.

Next, the present invention will be explained with reference to an embodiment shown in FIGS. 3 and 4 of the accompanying drawings.

FIG. 3 is a plan view showing a joint between wall sections of a vacuum vessel for a plasma device according to the present invention, and FIG. 4 is a sectional view taken along line 1--2 in FIG.

In these figures, the ends of the vacuum vessel wall sections 1 and 2 are formed with flanges 3 and 4, respectively.

The flange part 3 extends along the vessel wall 1 from the inner side end of the vacuum vessel, and the flange part 4 extends continuously from the outer surface of the vessel wall 2 to the vessel wall 1.
The flange portions 3 and 4 overlap each other.

It should be noted here that the flange parts 3 and 4 both extend at right angles to the thickness direction of the vacuum vessel wall, that is, they extend along the vessel wall and do not extend beyond the thickness of the vessel wall. .

In order to seal the small gap between the flange part 3 and the flange part 4 against the high vacuum inside the vacuum vessel, a part of the vessel wall 2 is removed and the tip of the flange part 3 and the attachment of the flange part 4 are removed. A relatively large space is formed between the base and the welding bellows 13 and 14, and welding bellows 13 and 14 are welded into this space.

Each bellows 13 and 14 has a substantially deep U-shaped cross section, and one end is welded to the container wall 1 or 2, respectively, before assembly of the vacuum vessel, and the other ends of the bellows 13 and 14 are welded to each other during assembly. The space between the flange portions 3 and 4 is sealed against high vacuum.

A bolt 5 passing through the flange parts 3 and 4 is screwed into a screw hole 8 formed in the flange part 4, and fixes the flange part 3 to the flange part 4 via a washer 15.

In order to seal between the flange portion 3 and this bolt 5,
A sealing device 19 consisting of a sealing ring 17 and a sealing cup 18 welded to the sealing ring 17 is welded into the recess 16 formed at least around the head of the bolt 5 .

This sealing device 19 is recessed within the recess 16.

In the vacuum container of the present invention configured in this way, the fourth
As is clear from the figure, the inner and outer surfaces of the vacuum vessel are substantially free of any protruding parts, unlike the conventional vacuum vessel shown in FIGS. 1 and 2.

Therefore, the space inside and outside the vacuum container can be used effectively, and the cost of the device relative to the plasma volume can be reduced.

Moreover, in order to disassemble the vacuum container of the present invention, the welded sealing device 19 and the welding bellows 13 and 14 are cut by melting.
Just remove bolt 5.

When the sealing device 19 is fused, the fusion is cut between the sealing ring 17 and the sealing cup 18, so that the material of the flange portion 3 can be prevented from deteriorating.

Similarly, the welding bellows 13 and 14 are cut by the welding bellows 1.
Since the welded portion between the welding bellows 3 and the welding bellows 14 is fused, the material of the flange portions 3 and 4 is not deteriorated.

To reassemble the sealing device 19, a new and different sealing cup 18 must be used, but since the sealing cup 18 is small, the replenishment costs are small and the sealing cup 18 Since the welding between the sealing ring 17 and the sealing ring 17 is a small circular welding, this welding can be easily carried out using known automatic welding techniques.

When the welding bellows 13 and 14 are to be re-welded, the legs of the welding bellows 13 and 14, which were welded to each other, are welded together while remaining short due to being fused during the previous disassembly.

Therefore, the welded bellows 13 and 14 that are once disassembled and then reassembled have shorter legs that abut against each other.

When the welded bellows 13 and 14 having the structure shown in Figs. 3 and 4 are used, it is possible to disassemble and reassemble about 10 times, and if the welded bellows 13 and 14 are replaced with new ones, further disassembly and reassembly are possible. The number of reassemblies can be increased.

Therefore, disassembly and reassembly can be repeated many times without substantially degrading the materials of the flange parts 3 and 4, and the life of the vacuum container can be significantly extended.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the vessel wall joint of a conventional vacuum vessel for plasma equipment, FIG. 3 is a partial plan view showing the vessel wall joint of the vacuum vessel for plasma equipment of the present invention, and FIG. The figure is a sectional view taken along the line ■-■ in FIG. 3. 1.2... Instrument wall, 3, 4... Flange portion, 5... Bolt, 13, 14... Welding bellow, 19... Sealing device.

Claims (1)

[Claims] 1 Flange portions extending along the vessel wall of the vacuum vessel, overlapping each other, and connected by bolts extending perpendicularly to the vessel wall, a welding bellow sealing between the flange portions of the vessel wall, and the bolts and the above-mentioned A vacuum container for a plasma device, which is equipped with a sealing device that seals between the flange part and the flange part.