JPH04148084A - Regenerating device for cryopump - Google Patents

Abstract

PURPOSE:To discharge residual gas sticking to an adsorber into the atmosphere upon regeneration, by providing a selector valve for switching the stream of working fluid from a compressor, between a suction and exhaust device and a fluid supply unit. CONSTITUTION:A cryopump comprises a fluid supply device 1 in which a compressor 2, a heat-exchanger 3, an oil separator 4 and an adsorber 5 are connected together in series, a suction and exhaust device 6 composed of a suction valve 7 and an exhaust valve 8, a casing 12 having a chamber 10 to be evacuated up to a high vacuum and attached to a frame 11, an ultra-low temperature expansion device 13 and a load unit 9 composed of an adsorber 4. In this arrangement, a four-way selector valve 15 for supplying working fluid from the adsorber 5 to the suction valve 7 or the exhaust valve 8 between the fluid supply unit 1 and the intake and exhaust device 6 is provided. During regeneration, the ultra-low temperature expansion device 15 is heated by the working fluid so as to evaporate liquid-like or solid-like gas attached to the adsorber 4 in order to prevent the ultra-low temperature expansion device 13 from being locally heated.

Description

[Detailed description of the invention] (b) Industrial application field This invention relates to an improvement in a regeneration device for a talio pump.

(b) Conventional technology The conventional cryopump is, for example, the Utility Model Publication No. 60-42235.
The structure is as shown in the publication. here,
A conventional example will be explained with reference to this publication. In Figure 4,
50 is a pump body attached to the object to be decompressed. A cylindrical cold head 51 is erected from the bottom of the central portion of the pump body. This cold head is composed of a first stage cold head 52 forming the lower part and a second stage cold head 53 forming the upper part. Inside the cold head 51, a coolant passage (150 not shown) is provided in which a coolant such as liquid helium circulates. - A heating plate 54 is fitted in a hook shape at the connection portion between the second stage cold head 52 and the second stage cold head 53. A radiation shield 55 with an open top is mounted on the heating plate 54 to accommodate the second stage cold head 53. A cooling plate 56 is attached to the tip of the second stage cold head 53. Cooling plate 5
A radiation shield 55 is provided above the cooling plate 6, facing the cooling plate.
A baffle 57 is provided to surround the opening.

Further, the heating plate 54 is electrically connected to a heating temperature control circuit 58 provided outside the pump body 50. A regeneration gas supply pipe 61 and an exhaust pipe 62 are connected to the pump body 50 via pulps 59 and 60.

In the cryopump having this structure, during regeneration, the heating plate 54 is heated to a predetermined temperature by the heating temperature control circuit 58 to vaporize water vapor, neon, helium, etc. that have been completely captured within the pump body 50, while the regeneration gas supply pipe 61 and The valves 59 and 60 of the exhaust pipe 62 are opened to supply dry nitrogen gas as a regeneration gas from the regeneration gas supply pipe 61 into the pump body 50, and the gas inside the pump body 50 is quickly exhausted from the exhaust pipe 62 to the outside by the regeneration gas. The exhaust is exhausted.

(c) Problems to be Solved by the Invention However, in conventional cryopumps, during regeneration, gas adsorbed on the cooling plate 56 or condensed on the radiation shield 55 is heated by the heating plate 54 and vaporized. There was a problem in that the radiation shield 55 was locally heated by this heating plate, and the solder-connected portion inside the cold head 51 melted, making it impossible to function as a cryogenic expander.

(d) Means for Solving the Problems This invention comprises a fluid supply unit formed by a compressor, an oil separator, and an adsorber, an air supply/exhaust device that can be connected to this fluid supply unit through piping, a cryogenic expander, and an adsorption device. In the cryopump regeneration device, which is configured with a load unit, a switching valve for switching the flow of working fluid from the compressor is provided between the supply/exhaust device and the fluid supply unit.

(*) Effect This invention is constructed as described above, so that the working fluid that can be supplied from the fluid supply unit to the cryogenic expander of the load unit is reversely supplied to the air supply and exhaust device during cryogenic operation and during regeneration operation. During regeneration operation, the cryogenic expander is heated with a working fluid to vaporize the liquid or solid gas adhering to the adsorption device so that the cryogenic expander is not locally heated.

(F) EXAMPLE The present invention will be explained below based on the example shown in FIGS. 1 and 2.

1 is a fluid supply unit, and this fluid supply unit is constructed by connecting a compressor 2, a heat exchanger 3, an oil separator 4, and an adsorber 5 in series. Reference numeral 6 denotes an air supply/exhaust device, and this air supply/exhaust device is composed of an air intake valve 7 and an exhaust valve 8. Reference numeral 9 denotes a load unit, which includes a casing 12 attached to a frame 11 having a high vacuum chamber 10, a cryogenic expansion machine 3 housed in this casing, and an adsorption unit attached to this expander. It is composed of a device 14. Reference numeral 15 denotes a four-way switching valve, which is provided between the fluid supply unit 1 and the supply/exhaust device 6, and directs the working fluid flowing out from the adsorber 5 of the fluid supply unit to the air supply valve 7 of the supply/exhaust device 6 or The gas is supplied to the exhaust valve 8. The four-way switching valve 15 is provided with a pressure reducing device [16] that returns the working fluid from the adsorber to the suction side of the compressor 2 when the adsorber 5 supplies working fluid to the exhaust valve 8.

The cryogenic expander 13 has a cylinder 17 attached to the casing 12 and housing a displacer (not shown) inside.
It is formed of. This cylinder is formed by a first cylinder 18 that performs the first stage expansion and a second cylinder 19 that performs the second stage expansion.

The adsorption device 14 includes a radiation shield 21 attached to the first cold head 20 of the first cylinder 18 and provided along the inner wall of the casing 12, and a talion panel attached to the second cold head 22 of the second cylinder 19. 2
3, and a baffle 24 attached to the radiation shield 21 at the top of this Talio panel.

A mechanical vacuum pump 25 is attached to the frame 11 to create a high vacuum in the chamber 10 and the casing 12 to a vacuum of 10-' Torr in advance. 26 is a temperature sensor that detects the temperature of the second cold head 22.

In the cryopump regeneration device configured as described above, the interior of the chamber 1o of the frame 11 and the interior of the casing 12 are first evacuated to a pressure of 10 −1 Torr by the vacuum pump 25 . Next, the working fluid such as helium compressed by the compressor 2 is expanded by a displacer in the cylinder 17 of the cryogenic expander 13 to generate cold, and the first cold head 2° is at 80' and the second cold head is at 80'. The head 22 is cooled to a cryogenic temperature of 5°. The residual gas in the chamber lo and the casing 12 is captured by the baffle 24 and the cryopanel 23, and the interior of the chamber 10 of the frame body 11 is made into a high vacuum of 10-'' Torr.

That is, the working fluid compressed by the compressor 2 is transferred to the heat exchanger 3.
The oil is cooled, and the oil is removed by an oil separator 4 and an adsorber 5. The four-way switching valve 15 switches the adsorber 5 to communicate with the air supply valve 7 of the supply/exhaust device 6, and communicates the suction side of the compressor 2 with the exhaust valve 8, respectively. Therefore, the working fluid flowing out from the adsorber 5 flows as shown by the solid arrow and flows into the four-way switching valve 15, the air supply valve 7, and the first and second cylinders 18 and 19, generating cold. The cold head 2o is cooled to 80' and the second cold head 22 is cooled to 15°K.

Furthermore, when the amount of residual gas captured by the baffle 24 or the cryopanel 23 exceeds the exhaust capacity, the cryopump can complete its regeneration operation. During regeneration, the working fluid compressed by the compressor 2 similarly flows through the heat exchanger 3, oil separator 4, and adsorber 5. The four-way switching valve 15 uses the adsorber 5 as the exhaust valve 8 and the suction side of the compressor 2 as the air supply valve 7.
are switched so that they communicate with each other. Therefore, the working fluid flowing out from the adsorber 5 flows as shown by the dotted arrow and flows into the four-way switching valve 15, the exhaust valve 8, and the first and second cylinders 18 and 19, and flows into the first and second cold heads 20.
．． 22 to vaporize the residual gas trapped in the cryopanel 23 and baffle 24 and release it into the atmosphere.
This ensures that no residual gas remains in the cryopanel or baffle. That is, during regeneration, high-temperature working fluid flows into the cylinder 17 in the exhaust stroke, and by preventing the working fluid from fully expanding within this cylinder, it is possible to prevent the occurrence of cold inside the cylinder 17. There is. In addition, by heating the entire cylinder 17 with fully compressed working fluid, local high temperatures can be suppressed, and even if the joints are connected with solder that is stable at extremely low temperatures, the heat-resistant solder is regenerated. Cryogenic expansion machine 13 that can prevent melting at times
to prevent it from being corrupted during playback.

The pressure reducing device installed in the four-way switching valve 15 directly returns part of the working fluid flowing out from the adsorber 5 to the suction side of the compressor 2 to the compressor 2 during regeneration, thereby reducing the pressure in the cylinder of the cryogenic expander 13 of the load unit 9. The amount of working fluid supplied to this cylinder is adjusted so that the temperature of cylinder 17 does not rise rapidly near normal temperature.

By attaching the temperature sensor 26 to the second cold head 22, it is possible to prevent the temperature of the second cold head 22 from rising abnormally during regeneration. That is, the temperature sensor 26 causes the compressor 2 to be stopped or to enter refrigeration operation when the second cold head 22 reaches a predetermined temperature.

In the above explanation, the four-way switching valve 15 was explained, but as shown in FIG.
．． It goes without saying that the same effect can be obtained even if the four-way switching valve 30 is used in place of the four-way switching valve.

(G) Effects of the Invention As described above, according to the present invention, a switching valve for switching the flow of working fluid from the compressor is provided between the supply/exhaust device and the fluid supply unit, so that the load unit can be By simply reversing the flow of the working fluid during regeneration of the cryoexpander, residual gas adhering to the handling equipment can be released into the atmosphere, and the entire cylinder of the cryoexpander can be uniformly heated. This prevents damage caused by localized heating.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a cryogenic unit showing one embodiment of the present invention, Fig. 2 is a sectional view of a cryogenic expander, and Fig. 3 is a circuit diagram of a cryogenic unit showing another embodiment. FIG. 4 is a sectional view of a conventional cryogenic expander. 1...Fluid supply unit, 2...Compressor, 4.
・・Oil separator, 5・・Adsorba,
6... Supply and exhaust system, 9... Load unit,
13...Cryogenic expansion machine, 14...Adsorption device,
15...Four-way switching valve, 27.2g, 29.30.
··solenoid valve.

Claims (1)

[Claims] 1. Consists of a fluid supply unit formed by a compressor, an oil separator, and an adsorber, an air supply/exhaust system connected to this fluid supply unit via piping, and a load unit formed by a cryogenic expander and adsorption device. A cryopump regeneration device, characterized in that a switching valve for switching the flow of working fluid from a compressor is provided between the supply/exhaust device and the fluid supply unit.