JPH0643644Y2 - Helium compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a helium compressor used in a cryogenic refrigerator, a cryopump and the like.

(B) Conventional technology In the cryogenic refrigerator described above, the cryogenic engineering handbook (Showa
As disclosed in Uchida Otsuruho Shinsha Co., Ltd. (September 15, 1957, P103-P107), a working gas such as helium gas compressed by a compressor is supplied to an expander to cool it to a cryogenic state. It has been known.

2 and 3 each show one example of a conventional helium compression device. In these figures, the compressor 1
The discharge port 1A is connected to the gas supply port 5 through the helium cooler 2, the oil filter 3 and the adsorber 4 in this order,
The gas return port 6 is connected to the suction port 1B of the compressor 1 through a check valve 7 by piping. Also, in the case of FIG. 3, the compressor 1
A buffer tank 9 is provided in the pipe 8 near the suction port 1B. Piping between the oil filter 3 and the adsorber 4
The check valve 7 and the pipe 8 between the check valve 7 and the suction port 1B of the compressor 1 are connected by a bypass pipe 12 provided with a pressure adjusting valve 11 that opens at a set pressure or higher. Further, the oil filter 3 and the pipe 8 are bypass pipes provided with a capillary tube 13.
Connected at 14. Also, the compressor 1 has a communication circuit 15
The oil cooler 16 is connected via.

In the above-described compression device, the high temperature and high pressure helium gas discharged from the discharge port 1A of the compressor 1 is first supplied to the helium cooler 2. Then, the helium gas cooled to room temperature by the helium cooler 2 enters the oil filter 3, where the oil contained in the helium gas is separated. Then, the helium gas that has passed through the oil filter 3 enters the adsorber 4, and the gaseous oil not removed by the oil filter 3 and the impurities contained in the helium gas are adsorbed by the adsorbent. The normal temperature and high pressure helium gas from which oil and impurities have been removed in this way is sent from the gas supply port 5 to an expansion device (not shown). On the other hand, the low-pressure helium gas of the expansion device passes through the gas return port 6 and the check valve 7 (further, the buffer tank 9 in FIG. 3), and then the suction port 1B of the compressor 1.
Returned to.

Since the gas temperature of the expansion device is high at the beginning of the operation of the compressor 1, the gas pressure on the discharge side of the compressor 1 becomes high and becomes equal to or higher than the set pressure of the pressure regulating valve 11. At this time, the pressure control valve 11 allows a part of the helium gas in the high-pressure side pipe 10 to escape to the low-pressure side pipe 8 through the bypass pipe 12 to prevent an abnormal increase in the high-pressure pressure. After that, when the gas temperature of the expansion device is lowered and the high pressure becomes lower than the set pressure, the pressure adjusting valve 11 is closed.

The oil separated by the oil filter 3 is recovered by the compressor 1 through a bypass pipe 14 having a capillary tube 13 and a suction side pipe 8 of the compressor 1. Further, the oil of the compressor 1 is circulated and supplied to the oil cooler 16 through the communication circuit 15 to prevent overheating.

(C) Problems to be Solved by the Invention In the helium compression device described above, the oil of the oil filter 3 is returned to the pipe 8 between the check valve 7 and the suction port 1B of the compressor 1. Therefore, even if the check valve 7 has a small amount of leakage in the reverse direction, oil may flow through the check valve 7 and the gas return port 6 to the expansion device, and the expansion device may be contaminated with the oil. Further, since the oil filter 3 is located on the upstream side of the bypass pipe 12 having the pressure regulating valve 11, the compressor 1
When the helium gas that is not supplied to the expansion device is started at the beginning of the operation, the oil is separated by the oil filter 3, the oil filter 3 is clogged early, and the life of the oil filter 3 is shortened. was there.

This invention was made in view of the above-mentioned fact,
The purpose of the present invention is to prevent oil from leaking to the expansion device, prevent the oil filter from performing unnecessary oil separation, and prolong the life of the oil filter.

(D) Means for solving the problem This invention is to connect the discharge port of a compressor to a gas supply port through a helium cooler, an oil filter and an adsorber in this order, and to connect a gas return port through a check valve. (EN) A helium compressor which is connected to a suction port of a compressor and has an oil filter connected to a pipe between a check valve and a suction port of a compressor by a bypass pipe having a capillary tube. In this invention, the pipe between the helium cooler and the oil filter is connected to the pipe between the check valve and the suction port of the compressor by a bypass pipe having a pressure control valve that opens above a set pressure, and A buffer tank is provided in the middle of the pipe between the gas return port and the check valve.

(E) Action With this configuration, even if the check valve leaks in the reverse direction when the helium compression device is not operating, the backflowed oil is absorbed in the buffer tank and does not flow into the expansion device. Also, since the bypass pipe equipped with the pressure control valve is connected to the upstream pipe of the oil filter,
When the pressure regulating valve is open, helium gas flowing through the bypass pipe equipped with the pressure regulating valve does not pass through the oil filter, and there is no fear of causing unnecessary oil separation in the oil filter.

(F) Embodiment Hereinafter, an embodiment of the present invention shown in the drawings will be described.
In FIG. 1, a discharge port 17A of a compressor 17 is connected to a gas supply port 21 through a helium cooler 18, an oil filter 19 and an adsorber 20 in sequence, and a gas return port 22 is a buffer tank 23 and a check valve 24. Through the suction port 17 of the compressor 17
Connected to B. An oil return port 19A below the oil filter 19 is connected to a pipe 27 between the check valve 24 and a suction port 17B of the compressor 17 via a bypass pipe 26 having a capillary tube 25. Also, the pipe 28 between the helium cooler 18 and the oil filter 19, the check valve 24, and the compressor
A pipe 27 between the suction ports 17B of 17 is connected by a bypass pipe 30 equipped with a pressure regulating valve 29 that opens at a set pressure or higher. Further, the compressor 17 and the oil cooler 31 are connected via a communication circuit 32.

According to this embodiment, since the buffer tank 23 is provided in the pipe 33 between the gas return port 22 and the check valve 24, even if the check valve 24 leaks in the reverse direction, the check valve 24 can be provided. The oil that flows back is absorbed by the buffer tank 23, and there is no concern that it will flow out from the gas return port 22 to the expansion device. Further, the bypass pipe 30 having the pressure adjusting valve 29 is connected to the oil filter 19 upstream pipe 28.
Therefore, the helium gas flowing through the bypass pipe 30 does not flow through the oil filter 19 due to the high pressure increase at the beginning of the operation of the compressor 17. Therefore, only the helium gas supplied to the expansion device can be passed through the oil filter 19, and unnecessary oil separation can be prevented.

(G) Effect of the Invention Since the invention is configured as described above, even if the check valve has a leak in the opposite direction, the oil leaked from the check valve is absorbed by the buffer tank and the oil expansion device is used. It is possible to reliably prevent the outflow to the side, to prevent the expansion device from being contaminated with oil, and when the pressure control valve opens, oil flows to the bypass pipe instead of flowing to the oil filter,
The oil filter can be prevented from wasteful oil separation, the life of the oil filter can be extended, and the reliability can be greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a piping diagram of a helium compression device showing an embodiment of the present invention, and FIGS. 2 and 3 are piping diagrams showing an example of a conventional device, respectively. 17 …… Compressor, 17A …… Discharge port, 17B …… Suction port, 18 ……
Helium cooler, 19 ... Oil filter, 20 ... Adsorber, 21 ... Gas supply port, 22 ... Gas return port, 23 ... Buffer tank, 24 ... Check valve, 25 ... Capillary tube, 26 ... … Bypass pipes, 27, 28, 33 …… Piping, 29 ……
Pressure control valve, 30 ... Bypass pipe.

Claims (1)

[Scope of utility model registration request] 1. A discharge port of a compressor is connected to a gas supply port through a helium cooler, an oil filter and an adsorber in this order, and a gas return port is connected to a suction port of a compressor via a check valve. In a helium compression device in which an oil filter is connected to a pipe between a check valve and a suction port of a compressor by a bypass pipe having a capillary tube, a check valve is provided between a helium cooler and an oil filter. Connect a bypass tank with a pressure control valve that opens above the set pressure to the pipe between the compressor and the suction port of the compressor, and install a buffer tank in the middle of the pipe between the gas return port and the check valve. A helium compression device characterized by being provided.