JP2000320791A - Bayonet joint for low temperature fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent freezing of grease and an O-ring and freezing of a turn joint part, maintain sealing performance, and guarantee movability of a first thermal insulation pipe and a second thermal insulation pipe even if the pipes are arranged in vacuum atmosphere. SOLUTION: Attention is directed to the maintenance of a temperature of an O-ring 4 part between a first thermal insulation pipe 2 and a second thermal insulation pipe 3 at such temperature that prevents freezing. This bayonet joint for low temperature fluid has the first thermal insulation pipe 2 and the second thermal insulation pipe 3 fitted in the first thermal insulation pipe capable of transferring low temperature fluid, a sealing member 4 sealing between the first thermal insulation pipe 2 and the second thermal insulation pipe 3, and temperature holding means (jacket for heat insulation 21, an electric heater 25) provided in a part of the sealing member 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bayonet joint for a low-temperature fluid, and more particularly to a cooling operation of a silicon wafer in an ion implantation apparatus for implanting various ions into a silicon wafer or the like in manufacturing a semiconductor, or a plasma surface treatment apparatus. Pipes for transferring cooling medium used for transferring low-temperature fluids such as liquid nitrogen and liquid helium for cooling operations during coating, etc., and for low-temperature fluids that can be applied for transferring low-temperature fluids in other pipes It is about a joint.

[0002]

2. Description of the Related Art A conventional bayonet joint has a structure in which a pair of pipes are inserted into each other, so that heat entering from the outside can be suppressed low, so that a low-temperature fluid such as liquid nitrogen or liquid helium is transferred. It is often used as a pipe joint. However, the conventional low-temperature fluid bayonet joint is a fixed pipe, and even if it is connected for low-temperature fluid transfer, it can hardly move relatively. In addition, the link pipe incorporating the bayonet joint is used for a long period of time, and is required to have durability.

[0003] In a cooling medium transfer pipe which adopts a low-temperature fluid as a cooling medium and transfers it to an object to be cooled, a pair of pipes are rotatable relative to each other around their respective axes. Fig. 2 shows a proposed bayonet joint for a low-temperature fluid that can be moved even a little.
An outline is based on this.

FIG. 2 is a cross-sectional view of a proposed low-temperature fluid bayonet joint 1. The low-temperature fluid bayonet connection 1 is a combination of a first heat insulating pipe 2 and a second heat insulating pipe 3. And an O-ring 4 (seal member) and a cap nut 5. The first heat-insulating pipe 2 has a double-pipe structure, and its inside is a first heat-insulating vacuum section 6. The second heat-insulating pipe 3 also has a double-pipe structure, and its inside is a second heat-insulating vacuum section 7.
The end of the first heat-insulating pipe 2 is inserted into the interior of the first heat-insulating pipe 2 as a concave portion, with the convex portion of the second heat-insulating pipe 3 extending over a predetermined length (insertion portion 8). At the same time, a small gap between the fitting portions is used as an attached heat insulating portion 10.

The innermost part (room temperature side) of the attached heat insulating part 10
In addition, the O-ring 4, the stopper 11 for preventing falling off and the flange 12 for preventing falling off, which can prevent the insertion portion 8 from coming off, and the cap nut 5 are provided.
Therefore, the first heat-insulating pipe 2 and the second heat-insulating pipe 3 do not move relative to each other in the axial direction, but have a small gap (attached heat-insulating portion 10). The part 8) is relatively rotatable.

Grease 13 is applied to the O-ring 4 and further to the stopper 11 for stopper and the flange 12 for stopper so that the rotation of the first heat-insulating pipe 2 and the second heat-insulating pipe 3 is ensured. Lubricate. When rotating the first heat insulating pipe 2 or the second heat insulating pipe 3, the cap nut 5 may be loosened.

A low-temperature fluid flow path 14 is formed by the first heat-insulating pipe 2 and the second heat-insulating pipe 3,
A low-temperature fluid, for example, liquid nitrogen LN can be supplied in one direction through the inside of the chamber 4, and a cooled object (not shown) can be cooled, and the nitrogen gas G gasified by thermal contact with the cooled object
The supply can be fed back in a mixed phase with N. Of course, by disposing a fluid supply pipe (not shown) in the center of the low-temperature fluid flow path 14, the inside of the fluid supply pipe is used as a supply passage, and the fluid supply pipe and the first heat-insulating pipes 2 and 2
A return passage may be formed between the heat-insulating pipe 3 and the heat-insulating pipe 3.

[0008] Although there is a possibility that the nitrogen gas GN leaks from the part of the attached heat insulating part 10, it is sealed by the O-ring 4 and the attached heat insulating part 10 has only a small gap. The nitrogen gas GN that has entered the can hardly convection even if there is a slight temperature difference,
Due to the presence of the low-temperature nitrogen gas GN, an adiabatic effect can be exhibited. Also, since the O-ring 4 is at about room temperature, the O-ring 4 does not freeze and can be lubricated with the grease 13 or the like as described above. Further, the first heat insulating pipe 2 and the second heat insulating pipe 3
If it is made of a thin stainless steel material, the amount of heat penetrating through this portion and entering the low-temperature portion can be extremely reduced.

Even when pressure is applied to the liquid nitrogen LN or the nitrogen gas GN, the stopper 11 and the flange 12 are engaged with each other and fixed by the cap nut 5. The insertion portion 8 is prevented from jumping out or coming out due to this pressure.

[0010] Such a bayonet joint 1 for a low-temperature fluid.
In the case where this is provided in a straight line, for example, one of the first heat insulating pipe 2 and the second heat insulating pipe 3 is bent at an arbitrary angle (for example, a right angle) from the middle, and By combining the low-temperature fluid bayonet joint 1 to form a multi-node link,
It is possible to construct a transfer pipe for a low-temperature fluid (cooling medium) in three dimensions. That is, since the rotation of the rotary joint 9 is possible, the cooling medium can be transferred over an arbitrary range following the movement of the object to be cooled.

However, when the low-temperature fluid bayonet joint 1 is used for low-temperature piping in the vacuum atmosphere of various vacuum devices (not shown), the outside of the low-temperature fluid bayonet connection 1 is vacuum. When the cryogenic fluid such as liquid nitrogen LN or liquid helium flows through the inside of the low-temperature fluid bayonet joint 1 (low-temperature fluid passage 14), the sealing portion formed by the O-ring 4 is insulated. Even if the one portion is relatively long, the sealing portion of the O-ring 4 is gradually cooled by the heat conduction effect on the tube walls of the first heat-insulating pipe 2 and the second heat-insulating pipe 3, and finally the O-ring in the rotary joint portion 10 is finally cooled. The ring 4 and the grease 13 freeze. When the O-ring 4 freezes, the sealing performance deteriorates to cause leakage of the low-temperature fluid, and the frozen grease 13 damages the first heat-insulating pipe 2 and the second heat-insulating pipe 3 or, if severe, damages the first heat-insulating pipe 2 and the second heat-insulating pipe 3. There is a problem that two tubes of the first heat insulating pipe 2 and the second heat insulating pipe 3 are fixed.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. Particularly, even when piping is performed in a vacuum atmosphere, it is possible to prevent the rotation joint portion from freezing. An object of the present invention is to provide a bayonet joint for cryogenic fluid that can guarantee mobility.

Another object of the present invention is to provide a low-temperature fluid bayonet joint that can maintain movability by preventing freezing of grease, particularly in a low-temperature pipe having a movable portion that performs lubrication with grease.

Another object of the present invention is to provide a low-temperature fluid bayonet joint which can prevent freezing of an O-ring and maintain a sealing performance in a low-temperature pipe provided with a sealing portion formed by an O-ring.

Another object of the present invention is to provide a bayonet joint for a low-temperature fluid capable of ensuring the movability of the first heat insulating pipe and the second heat insulating pipe.

[0016]

That is, the present invention provides the following:
The present invention focuses on maintaining the temperature of the O-ring portion between the heat-insulating pipe and the second heat-insulating pipe at a temperature that can prevent freezing, and is a low-temperature fluid bayonet coupling for transferring a low-temperature fluid, A first heat-insulating pipe and a second heat-insulating pipe fitted to the first heat-insulating pipe capable of transferring a low-temperature fluid, and a seal between the first heat-insulating pipe and the second heat-insulating pipe. A seal member, and a temperature holding unit provided at a portion of the seal member;
It is a bayonet joint for low-temperature fluid characterized by having.

[0017] The temperature holding means may be provided at a lower temperature side of the seal member.

The above-mentioned temperature maintaining means can be a heat retaining jacket or an electric heater.

The seal member can be lubricated by applying grease.

The above-mentioned heat insulation jacket can be used as a water jacket so that hot water or another fluid for heat insulation can flow.

In the bayonet joint for a low-temperature fluid according to the present invention, a temperature maintaining means such as a heat retaining jacket or an electric heater is provided at a sealing member portion such as an O-ring between the first heat insulating pipe and the second heat insulating pipe. Therefore, even when used in a vacuum atmosphere, the rotation joint portion provided with the O-ring, grease and the like can be prevented from freezing, and the mobility and the sealing performance can be ensured.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a bayonet joint 20 for a low-temperature fluid according to an embodiment of the present invention will be described with reference to FIG. However, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the detailed description thereof is omitted. FIG. 1 is a cross-sectional view of the low-temperature fluid bayonet joint 20. In the low-temperature fluid bayonet connection 20, the low temperature of the O-ring 4 between the first heat insulating pipe 2 and the second heat insulating pipe 3 is low. A heat insulating jacket 21 (temperature holding means) is formed on the side (lower temperature side along the attached heat insulating portion 10 from the inlet side of the first heat insulating pipe 2).

The heat insulation jacket 21 has a heat insulation flow path 22 formed in an annular shape on the room temperature side of the first heat insulation vacuum section 6 of the first heat insulation pipe 2, and warm water flows from an inlet 23 through the heat insulation flow path. It flows into the passage 22 and is discharged from the outlet 24. The hot water is supplied via a flexible plastic tube (not shown) such as tetrafluoroethylene resin (PTFE resin), polyurethane or nylon. Also, instead of water, the temperature may be kept by another fluid for keeping warm, for example, warm air or other fluid.

Further, an electric heater 25 (see the phantom line in the figure) can be arranged in the heat retaining channel 22.
When the electric heater 25 is used, the heat insulating flow path 2
An optional configuration that directly keeps the temperature of the O-ring 4 portion without providing the 2 in particular may be adopted.

The example shown in FIG. 1 shows a case in which the outside of the low-temperature fluid bayonet joint 20 has a low vacuum (a pressure of 0.1 Pa or more). That is, in a low vacuum, in order to maintain the heat insulating performance of the internal pipes (the first heat insulating pipe 2 and the second heat insulating pipe 3) through which the low-temperature fluid flows, it is the same as in the case of using at atmospheric pressure. In addition, it is necessary to provide a high vacuum jacket (the first heat-insulating vacuum section 6 and the second heat-insulating vacuum section 7) outside. If the atmosphere in which the low-temperature fluid bayonet joint 20 is used is a high vacuum (pressure of 0.01 Pa or less), the use atmosphere becomes a high-performance adiabatic vacuum as it is, and a vacuum jacket is not required.

In the low-temperature fluid bayonet joint 20 having such a configuration, the link pipe comprising the first heat-insulating pipe 2 and the second heat-insulating pipe 3 is provided with a heat-preserving jacket 21 for preventing freezing.
The temperature of (the O-ring 4 and the grease 13) can be kept at room temperature to prevent freezing of these. Therefore, the sealing performance by the ring 4 and the grease 13
The lubrication performance can be maintained, and the movability of the first heat insulating pipe 2 and the second heat insulating pipe 3 can be ensured.

[0027]

As described above, according to the present invention, the link pipe comprising the first heat insulating pipe and the second heat insulating pipe is provided with temperature retaining means for preventing freezing, so that the rotary joint (O-ring) can be provided. And the temperature of the grease portion) is kept at a normal temperature to prevent freezing, to ensure the mobility of the rotating joint portion, and to allow the low-temperature pipe to function normally.

[Brief description of the drawings]

FIG. 1 is a sectional view of a low-temperature fluid bayonet joint 20 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a proposed low-temperature fluid bayonet joint 1;

[Explanation of symbols]

Reference Signs List 1 Bayonet joint for low-temperature fluid (FIG. 2) 2 First heat-insulating pipe 3 Second heat-insulating pipe 4 O-ring (seal member) 5 Cap nut 6 First heat-insulating vacuum section of first heat-insulating pipe 2 7 Second Second heat-insulating vacuum part of heat-insulating pipe 8 8 Insertion part 9 Rotating joint part 10 Attached heat-insulating part 11 Stopper for preventing fall-off 12 Flange for preventing fall-off 13 Grease 14 Low-temperature fluid channel 20 Low-temperature fluid bayonet joint (embodiment, figure 1) 21 Thermal insulation jacket (temperature maintaining means) 22 Thermal insulation flow path 23 Inlet of thermal insulation flow path 22 Outlet of thermal insulation flow path 22 25 Electric heater (Temperature maintaining means) LN Liquid nitrogen GN Nitrogen gas

Claims (5)

[Claims] 1. A low-temperature fluid bayonet joint for transferring a low-temperature fluid, the first heat-insulating pipe capable of transferring the low-temperature fluid, and a second heat-insulating pipe fitted to the first heat-insulating pipe. A first heat insulating pipe and a second heat insulating pipe, and a sealing member for sealing between the first heat insulating pipe and the second heat insulating pipe; Fittings. 2. The bayonet joint for a low-temperature fluid according to claim 1, wherein said temperature holding means is provided at a lower temperature side of said seal member. 3. The low-temperature fluid bayonet connection according to claim 1, wherein said temperature holding means is a heat insulation jacket. 4. The low temperature fluid bayonet joint according to claim 1, wherein said temperature holding means is an electric heater. 5. The low-temperature fluid bayonet joint according to claim 1, wherein the seal member is lubricated by applying grease.