JPH01123956A - Suction exhaust device for cryogenic refrigerator - Google Patents

Abstract

PURPOSE: To reduce the leakage of working gas and obtain a compact air supply and exhaust device with low power by forming a sliding device with a cam attached to a driving shaft and a pressing means for pressing a slide valve disk to come into contact with the cam. CONSTITUTION: An air supply and exhaust device 13 comprises a guide box 16, a slide valve disk 17 housed in the guide box and a sliding device 18 for sliding the valve disk in a reciprocating manner. The sliding device 18 is composed of a cam 20 attached to a driving shaft 19 and a coil spring 21 for pressing the slide valve disk 17 to come into contact with the cam. With this constitution, during a stroke in which a displacer 6 moves from a buffer space 7 side to an expansion space 8 side in a cylinder 4, the small diameter circular arch part 31 of the cam 20 is located in the slide valve disk 17 side and the slide valve disk is raised and held by the coil spring 21 so that an air supply and exhaust connection port 24 communicates with a low pressure line connection port 23 through an annular recess 27 and working gas in the cylinder 4 is exhausted to a compressor 1 from a low pressure line 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an improvement in the supply and exhaust system of a cryogenic refrigerator equipped with a gas cycle such as a Gifford-McMahon cycle or a Solvay cycle.

(b) Conventional technology Conventional cryogenic refrigerators of this type are described in the "Vacuum Technology Manual" (published by Sangyo Tosho Co., Ltd., July 30, 1981, p. 2).
20) (see FIG. 4), a cylinder 50, a displacer 51 that reciprocates up and down within the cylinder, and a displacer 51 that moves the cylinder 5 by the displacer.
a buffer space 52 and an expansion space 53 that are defined inside the displacer 51;
and a heat storage material 55 disposed in this gas flow path.

Compression device 56 that compresses working gas such as helium gas
and an air supply/exhaust device 60 that alternately communicates the air supply/exhaust port 57 of the cylinder 50 with a high pressure line 58 and a low pressure line 59 of the compression device 56, and this air supply/exhaust device includes an air intake valve 61 and an exhaust valve 62. is used. In addition, the cylinder 50
A load 65 is connected to the cold head 63 via a heat transfer member 64.

In the cryogenic refrigerator described above, when the displacer 51 is at the lowest position (top dead center) in the cylinder 50.

The air supply valve 61 is opened, the exhaust valve 62 is closed, and the working gas pressurized by the compression device 56 is caused to flow into the buffer space 52. In the process in which the displacer 51 moves from the lowest position to the highest position (bottom dead center) in the cylinder 50, the working gas in the buffer space 52 is cooled by the heat storage material 55 in the gas flow path 54 and is caused to flow into the expansion space 53. . Furthermore, as the displacer 51 moves, the volume of the expansion space 53 increases. When the displacer 51 is at the uppermost position in the cylinder 50, the air supply valve 61 is closed and the exhaust valve 62 is opened. Therefore, the working gas expands in the expansion space 53, generating cold. After that, displacer 5
In the process of 1 moving from the top to the bottom, the expansion space 53
The working gas flows through the gas passage 54 while cooling the heat storage material 55, and is further exhausted to the low pressure line 59 through the buffer space 52 and the exhaust valve 62. By repeating the above.

The cold head 63 of the cylinder 50 is cooled.

The load 65 is subjected to cryogenic cold.

(c) Problems to be Solved by the Invention In the cryogenic refrigerator described above, the air supply valve 6 of the air supply/exhaust device 60
Two poppet valves are often used for the exhaust valve 1 and the exhaust valve 62. However, the system using two poppet valves has disadvantages such as a complicated structure, a large number of parts, and a large air supply/exhaust system.

In addition, as disclosed in Japanese Patent Application Laid-Open No. 60-213777, when supplying and exhausting working gas is performed by a supply and exhaust device using one spool valve, the outer peripheral surface of the spool valve body and the spool valve Since sealing is achieved through contact with the inner circumferential surface of the cylindrical sleeve that reciprocally receives the body, there is a problem in that the resistance to leakage of the working gas is weak and the efficiency of the refrigerator is reduced.

Furthermore, an air supply/exhaust system using a rotary valve as disclosed in Japanese Patent Application Laid-Open No. 60-138369 has the disadvantage that the valve body has a long travel distance (and a large amount of power is required to operate the valve body). there were.

This invention was made in view of the above-mentioned facts.1
It is an object of the present invention to provide an air supply/exhaust device for a cryogenic refrigerator that is compact and has low power, which reduces the leakage of working gas and improves the efficiency of the refrigerator.

B) Means for solving the problem The present invention comprises an air supply/exhaust system comprising a guide box, a slide valve body housed in the guide box, and a sliding device for reciprocating the valve body, The guide box has a high pressure line communication hole that communicates with the high pressure line of the compression device.

A low pressure line communication hole that communicates with the low pressure line and an air supply/exhaust communication hole that communicates with the cylinder air supply/exhaust port are provided.

A recess is provided in the slide valve body to alternately communicate the high pressure line communication hole and the low pressure line communication hole with the supply/exhaust communication hole, and
The sliding device is formed by a cam attached to a drive shaft and a pressing means such as a slide valve element that presses the cam into contact with the cam.

(E) Function With the above-described configuration, the present invention switches the air supply and exhaust system between the air supply side and the exhaust side by sliding the slide valve body with a sliding device equipped with a cam. Eliminates the need to adjust the timing of switching the air supply and exhaust system, and
This allows the output for sliding the slide valve body to be reduced.

(f) Examples The present invention will be explained below based on the examples shown in FIGS. 1 and 2.

1 is a compression device, and a high pressure line 2 and a low pressure line 3 are connected to this compression device. A cylinder 4 houses a displacer 6 that slides back and forth by a shaft 5 driven by a crank mechanism (not shown).

A variable volume buffer space 7 and an expansion space 8 are defined by this displacer.

The buffer space and the expansion space communicate with each other via a space 9 within the displacer 6. A heat storage material 10 made of wire mesh is arranged within this space. The upper wall 11 of the cylinder 4 is provided with an air supply/exhaust port 12 that opens into the buffer space 7 .

Reference numeral 13 denotes a supply/exhaust device connected to the supply/exhaust port, and this supply/exhaust device alternately communicates the high pressure line 2 and the low pressure line 3 with the supply/exhaust port 12 . A load heat exchanger 15 is attached to the bottom wall 14 of the cylinder 4 to cool an object to be cooled.

The air supply/exhaust device 13 includes a guide box 16, a slide valve body 17 housed in the guide box, and a slide device 18 that slides the valve body back and forth.

The sliding device 18 includes a cam 20 attached to a drive shaft 19Vc, and a coil spring 21 that presses the slide valve body 17 into contact with the cam. The guide box 16 has a high pressure line communication hole 22 that communicates with the high pressure line 2 of the compression device 1.
and a low pressure line communication hole 23 communicating with the low pressure line 3,
Supply/exhaust communication hole 24 communicating with supply/exhaust port 12 of cylinder 4
and is provided. The slide valve body 17 includes a cylindrical valve portion 25 and a pin 26 that contacts the cam 20 and slides the valve portion 25 back and forth. The valve portion 25 is provided with an annular recess 27 that alternately communicates the high pressure line communication hole 22 and the low pressure line communication hole 23 with the supply/exhaust communication hole 24, and a coil spring 21 is inserted into the surface opposite to the pin 26. A recess 28 is provided. The valve portion 25 is provided with a passage 29 that communicates the recess 28 and the low pressure line communication hole 23.

The cam 20 has a large-diameter circular arc portion 30 that holds the slide valve body 17 downward and connects the high pressure line communication hole 22 and the supply/exhaust communication hole 24, and a large diameter arc portion 30 that holds the slide valve body 17 upward and connects the high pressure line communication hole 22 and the supply/exhaust communication hole 24. 23 and the supply/exhaust communication hole 24, and a medium diameter arc portion 32 that holds the slide valve body 17 in the middle so that the communication holes 22, 23, and 24 do not communicate with each other.

It is formed with an inclined portion 33 that moves the slide valve body 17.

The operating state of the slide valve body 17 in the air supply and exhaust system for the cryogenic refrigerator configured as described above will be explained. first,
When the displacer 6 is in the process of moving from the buffer space 7 side to the expansion space 8 side in the cylinder 4, the small diameter arc portion 31 of the cam 20 is located on the slide valve body 17 side, and this slide valve body is pushed by the coil spring 21. raised and held;
The supply/exhaust communication hole 24 and the low pressure line communication hole 23 are communicated through an annular recess 27, and the working gas in the cylinder 4 is exhausted from the low pressure line 3 to the compression device 1. Next, the displacer 6 is in the process of moving from the expansion space 8 side to the buffer space 7 side in the cylinder 4.

The large-diameter circular arc portion 30 of the cam 200 is located on the side of the slide valve body 17, and this slide valve body is pushed down and held, allowing the supply/exhaust communication hole 24 and the high pressure line communication hole 22 to communicate with each other through the annular recess 27. Working gas pressurized by the compression device 1 is supplied into the cylinder 4.

Further, when the displacer 6 is in the initial stroke and final stroke of moving from the expansion space 8 side to the buffer space 7 side, the inclined portion 33 and the medium diameter arc portion 32 of the cam 20 are located on the slide valve body 17 side, and this The slide valve element slides within the guide box 16, and holds each of the communication holes 22, 23, and 24 in a position where they are not communicated with each other, and switches the communication state of these communication holes, further expands the working gas, and causes the valve to release itself. I'm trying to keep it cool. By repeating the above operations, the supply/exhaust device 13 connects the supply/exhaust port 12 of the cylinder 4 to the high pressure line 2 and the low pressure line 3 alternately.

The slide valve body 17 contacts the cam 20 and slides inside the guide box 16, thereby increasing the stroke length.
The timing of switching does not shift due to wear, and
This prevents the cooling capacity from decreasing due to leaks.

Moreover, since the slide valve body 17 is slid by the cam 20, the switching timing can be freely adjusted by simply changing the shape of this cam.

The slide valve body 17 is slid by being pressed against the cam 2° by a coil spring 21, so that the output for sliding the slide valve body can be reduced.

In this invention, the slide valve body 17 for switching the flow path is connected to the cam 20.
By sliding the slide valve body, the switching timing can be easily adjusted using the slide valve body.

(G) Effects of the Invention The air supply and exhaust system for a cryogenic refrigerator according to the present invention includes a guide box, a slide valve body housed in the guide box, and a slide valve body housed in the guide box.
It consists of a sliding device that reciprocates this valve body, and the guide box has a high pressure line communication hole that communicates with the high pressure line of the compression device, a low pressure line communication hole that communicates with the low pressure line, and a cylinder air supply and exhaust port. The slide valve body is provided with recesses that alternately communicate the high pressure line communication hole and the low pressure line communication hole with the supply and exhaust communication hole, and the sliding device is attached to the drive shaft. Since the cam was formed by a cam and a pressing means that presses the slide valve body into contact with the cam, the flow path is opened by sliding the cam back and forth while the slide valve body is brought into contact with the cam by the pressing means. By switching, it becomes unnecessary to adjust the timing of switching, and the output for sliding the slide valve body can be reduced. Moreover.

The sliding state of the slide valve body can be adjusted freely by simply changing the shape of the cam.

[Brief explanation of the drawing]

1 and 2 show the present invention, FIG. 1 is a schematic sectional view of a cryogenic refrigerator, FIG. 2 is a sectional view of an air supply and exhaust system, and FIG. 3 is a conventional cryogenic refrigerator. frozen . FIG. 2 is a schematic cross-sectional view of the machine. 1... Compression device, 2... High pressure line, 3.
...Low pressure line, 4...Cylinder, 6...
Displacer. 7... Buffer space, 8... Expansion space, 9.
...Space, 10... Heat storage material, 12... Supply/exhaust port, 1
3... Supply and exhaust equipment, 1-6... Information box,
17...Slide valve body, 18...Sliding device, 20
...Cam, 21...Coil spring, 22...High pressure line communication hole. 23... Low pressure line communication hole, 24... Supply/exhaust communication hole. 27...Annular recess.

Claims (1)

[Claims] 1. A cylinder, a displacer that slides back and forth within the cylinder, a buffer space and an expansion space defined inside the cylinder by the displacer, and a gas flow path that communicates these buffer spaces and the expansion space. In a cryogenic refrigerator comprising a heat storage material provided, a compression device, and an air supply/exhaust device that alternately communicates an air supply/exhaust port of a cylinder with a high pressure line and a low pressure line of the compression device, the air supply/exhaust device comprises: A guide box, a slide valve body housed in the guide box, and a sliding device for sliding the valve body back and forth, the guide box having a high pressure line communication hole communicating with a high pressure line of the compression device, A low pressure line communication hole that communicates with the low pressure line and an air supply/exhaust communication hole that communicates with the supply and exhaust port of the cylinder are provided, and the slide valve body has supply and exhaust communication holes that alternate between the high pressure line communication hole and the low pressure line communication hole. A cryogenic device characterized in that a recess is provided to communicate with the drive shaft, and the sliding device is formed by a cam attached to the drive shaft and a pressing means for pressing the slide valve body into contact with the cam. Refrigerator air supply and exhaust system.