JPH0618110A - Cryopump device - Google Patents

Abstract

PURPOSE:To obtain a cryopump device, to which a reciprocating driving section reciprocating a displacer conducting expansion and cooling by a refrigerant in a cylinder is installed, solidly at low cost. CONSTITUTION:A stepped cylinder 10, in which each section element of the cylinder is divided and formed in other bodies respectively by dividing a cryopump device into a base section 101 fixed to a reciprocating driving section, a continuous cylindrical section 110, in which a first cylinder section 10A, a stepped section 106 and a second cylinder section 10B are unified, a first stage section 102 and a second stage section 103 and these other bodies are brazed and unified, is used. Accordingly, the cylinder is degassed through high- temperature heating purification, and the cylinder, in which there is no stress corrosion is manufactured, thus resulting in few trouble in the cryopump device, then forming constitution, in which no refrigerant is contaminated and expansion and cooling are conducted excellently and cost of which is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator such as a Gifode-McMahon cycle or Stirling cycle used for cryogenic refrigeration.

[0002]

2. Description of the Related Art The structure of a refrigerator of this type is disclosed in Japanese Patent Laid-Open No. 3-1.
For example, as shown in FIG. 5, a refrigerant such as helium compressed by the compression unit 1 is supplied from the conduit 2A to the expansion cooling unit 3, and a refrigerant expanded by the expansion cooling unit 3 is supplied from the conduit 2B. The compression system and the expansion system are returned to the compression unit 1 and pressurized by the compression unit 1 again to be supplied from the conduit 2A.

The expansion cooling unit 3 is formed by assembling a reciprocating motion unit 5 for performing an expansion cooling action on a reciprocating drive unit 4 such as an electric crank mechanism. The reciprocating body 8 in which the first displacer 6 having a large diameter for performing the expansion cooling action of the first stage and the second displacer 7 having a small diameter performing the expansion cooling action of the second stage are connected is Diameter 1st cylinder part 1
The reciprocating body 8 is reciprocally moved by the crank of the reciprocating drive unit 3 and the like, and is housed in a stepped cylinder 10 having a small cylinder portion 10B and a second cylinder portion 10B.

A cooling device having a structural portion for expanding and cooling the first and second displacers as described above is called a cryopump device. The stepped cylinder 10 is fixed to the reciprocating drive unit 4 by the thick flange-shaped base portion 101 provided at the opening end on the large diameter side, and the thick flange-shaped first portion provided at the stepped portion. It is fixed to the first object to be cooled 50 by the stage portion 102, and is fixed to the second object to be cooled 60 by the thick flange-shaped second stage portion 103 provided at the closed end on the small diameter side.

The stepped cylinder 10 is made of stainless steel material, that is, SUS material, from the viewpoint of strength under cryogenic temperature.

As for the temperature of each part, the reciprocating drive part 4 is at room temperature 300.
K, the first stage portion 102 is about 30K, and the second stage 103 is about 8K. Therefore, the distance between the base 101 of the cylinder 10 and the first stage 102 is 300.
Since the operation is performed with a temperature difference of about K: 30K and a temperature difference of about 30K: 8K between the first stage 102 and the second stage 103, the first cylinder 10A and the second cylinder 10A
In each of the intermediate portions 104 and 105 of the cylinder 10B, it is necessary to reduce the thickness of the intermediate portions 104 and 105 as much as possible so that the heat capacity due to the thickness does not hinder the cooling operation.

Therefore, as shown in FIG. 6, the intermediate portion 104
-105 is formed in a thin, stepped tubular shape with a flange. Although not shown, a vacuum chamber is formed on the outer circumference of the first cylinder 10A and the second cylinder 10B.

For manufacturing the stepped cylinder 10, for example, as shown in FIG. 7, the material of the portions corresponding to the first cylinder portion 10A and the second cylinder portion 10B is made into a thick pipe material, and the base portion 101 is made. And the first stage part 102 and the second
The material of the portion corresponding to the stage portion 103 is made into a thick plate material, and the whole material integrally joined by tungsten inert gas welding (also called TIG welding) or electron beam welding is made, and this material is cut and processed. It is formed like 6.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As shown in FIG.
In the method of joining by TIG welding or electron beam welding, there are disadvantages that welding defects and stress corrosion cracking are likely to occur, and the welding cost and processing cost are high. Care must be taken not to enter the bond gap, and if it does enter, post-treatment such as flux removal work is required, resulting in an increase in processing cost. Also,
Since the heating limit is low and degassing work cannot be performed sufficiently, hydrogen gas or the like is released from the outer surface of the cylinder during operation of the cryopump device, and the ultimate vacuum degree of the cryopump device is inferior. Further, it is possible to improve the refrigerating capacity by increasing the length of the first displacer 6 and the second displacer 7 in the stepped cylinder 10 in FIG. In the end, the diameter of the stepped cylinder 10 must be reduced, and the shape of the stepped cylinder 10 becomes difficult to eliminate each of the above disadvantages.

Therefore, there is a problem that it is desired to provide an inexpensive structure that does not have such inconvenience.

[0011]

According to the present invention, there is provided a thick flange-shaped base portion provided at the open end of the first cylinder portion on the large diameter side as described above, and the first cylinder and the second portion on the small diameter side. A stepped tubular cylinder having a thick flange-shaped first stage portion provided at a stepped portion between the cylinder portion and a thick flanged second stage portion provided at a closed end of the second cylinder portion. In a cryopump device in which a reciprocating drive unit for reciprocating the displacer is fixed to the base portion while reciprocating the displacer performing the expansion cooling operation, the base portion and the first cylinder portion are provided. And a stepped portion and a second cylinder portion are integrally formed into a continuous cylindrical portion, a first stage portion, and a second stage portion, which are formed as separate bodies. Wax denoted by providing a stepped shape cylinder formed integrally is obtained by adapted to solve the above problems due.

[0012]

[Function] Since each element part of the stepped cylinder is formed as a separate body, and then these separate bodies are integrally formed by hard brazing, it is easy to manufacture, inexpensive, robust, and resistant to high temperatures. Since the stepped cylinder is not decomposed even when heated, degassing can be performed by high temperature heating. For this reason, the cryopump device performs high-quality expansion cooling without contamination of the refrigerant, and has no failure due to stress corrosion or the like.

[0013]

EXAMPLES Examples will be described below with reference to FIGS.
1 to 4, parts indicated by the same reference numerals as those in FIGS. 5 to 7 are the same functional portions as those explained in these drawings.

First, the first embodiment will be described with reference to FIG.
In FIG. 1, the stepped cylinder 10 is made by dividing it into four parts. The first cylinder part 10A and the stepped part 1
06 and the second cylinder portion 10B are integrated into a continuous cylinder-shaped portion 110, which is an independent separate body, and the base portion 101, the first stage portion 102, and the second stage portion 103 are independent separate bodies. They are divided into bodies, and these are separately formed by machining so that they can be fitted to the positions of the required portions of the continuous cylindrical portion 110, and then these separate bodies are “hard brazed” to obtain the required body. It is formed in an integral shape.

In these fitting portions, an annular groove that goes around the fitting surface is formed as a hard brazing material groove 20 on the thick side, and this portion is used for "hard brazing". A rod-shaped or strip-shaped hard solder is wound so that it can be stored. Hard brazing is performed using "silver brazing", "brass brazing", or the like. The specific dimensions are, for example, as shown in FIG. 2, and the first cylinder portion 10A and the second cylinder portion 10B may have an elongated shape with a diameter: length ratio of about 1: 4 to 6. , Can be easily manufactured.

Next, a second embodiment will be described with reference to FIG.
In FIG. 3, the stepped cylinder 10 is made by dividing it into five parts. The points different from the first embodiment of FIG. 1 are the first cylinder part 10A and the second cylinder part 10B.
And are separately formed, and the stepped portion 106 is formed.
And the first stage portion 102 are integrally formed as a separate intermediate joined body portion 111, and the open end 10A1 of the first cylinder portion 10A is connected to the intermediate joined body portion 11 as a whole.
1 is that it is inserted into the body-attached portion 111A, and other portions are configured in the same manner as in the case of FIG. 1 as shown in the drawing.

Next, a third embodiment will be described with reference to FIG.
The stepped cylinder 10 is divided into five parts, which is different from the second embodiment shown in FIG.
The portion corresponding to 6 is divided into a divided portion 106A and a divided portion 106B, the divided portion 106A is integrally formed on the open end 10B1 side of the second cylinder portion 10B, and the divided portion 106B is formed together with the body portion 112A. First
Intermediate joined body portion 112 integrated with the stage portion 102
Is formed as a separate body, and in the gap portion 112B formed in a deep annular groove between the inner diameter side of the body portion 112A and the divided portion 106A, the opening end 1 of the second cylinder 10B is formed.
0B1 is fitted, and other parts are configured in the same manner as in the case of FIG. 3 as shown in the drawing.

In the above-mentioned first to third embodiments, the tubular open ends of the first cylinder portion 10A and the second cylinder portion 10B are constructed so as to be held by the thick portion of the portion joined to them. Yes, it does not deform even if it is heated to a high temperature by hard brazing.The solvent for hard brazing is generally borax or a mixture of borax, so when the solvent is hot, it becomes a glass body. Since it is a viscous body, extra hard solder does not stick out inside the stepped cylinder 10.

[Modified Implementation] The present invention can be modified and implemented as follows. (1) The base portion 101, the first stage portion 102, and the second stage portion 103 are made of copper-based material such as brass material.

(2) A hard solder groove is provided on the end side of each fitting portion in the shape of a single-sided groove.

[0021]

As described above, according to the present invention, since each element part of the stepped cylinder is formed as a separate body, these separate bodies are integrally formed by hard brazing.
It is easy to manufacture, and since it is a hard brazing, even if it is heated to a high temperature, the brazing part does not melt and the stepped cylinder does not decompose, and it is possible to perform degassing by high temperature heating, The degree of vacuum of the cryopump device can be further lowered, and the bluing and hardening of the SUS material can be performed. Therefore, the structure of the cryopump device can be made robust and inexpensive, and high-quality expansion and cooling without refrigerant contamination can be performed to reduce stress. It has the feature that it can be provided without any failure due to corrosion.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, and FIGS.
Shows the conventional one, and the contents of each figure are as follows.

FIG. 1 is a vertical sectional view of a stepped cylinder according to a first embodiment.

FIG. 2 is an explanatory view showing an example of specific dimensions of the first embodiment.

FIG. 3 is a vertical sectional view of a stepped cylinder according to a second embodiment.

FIG. 4 is a vertical sectional view of a stepped cylinder of a third embodiment.

FIG. 5 is a schematic configuration diagram of a cross section of the main part of the entire device

FIG. 6 is a vertical sectional view of a stepped cylinder.

FIG. 7 is a vertical cross-sectional view of the material structure of the stepped cylinder.

[Explanation of reference numerals] 1 compression section 2A pipeline 2B pipeline 3 expansion cooling section 4 reciprocating drive section 5 reciprocating section 6 first displacer 7 second displacer 8 reciprocating body 10 stepped cylinder 10A first cylinder section 10B No. 2 Cylinder part 10B1 Open end 20 Hard brazing material groove 50 First cooled object 60 Second cooled object 101 Base part 102 First stage part 103 Second stage part 104 Intermediate part 105 Intermediate part 106 Stepped part 106A Divided Part 106B Divided part 110 Continuous cylindrical part 111 Intermediate joined part part 111A Body part 111B Annular groove part 112 Intermediate joined part 112A Body part 112B Gap part

Claims (2)

[Claims] 1. A stepped portion between a thick flange-shaped base portion provided at an open end of a large diameter side first cylinder portion and a step portion between the first cylinder portion and a small diameter side second cylinder portion. In a stepped tubular cylinder having a thick flange-shaped first stage portion provided and a thick flange-shaped second stage portion provided at the closed end of the second cylinder portion, a displacer for performing expansion cooling operation is provided. A cryopump device that reciprocates and fixes a reciprocating drive unit for performing the reciprocating motion on the base portion, the base portion, the first cylinder portion, the stepped portion, and the second cylinder. A continuous cylinder-shaped portion in which the portions are integrated, the first stage portion, and the second stage portion, each of which is formed as a separate body, and each of the separate bodies is brazed together to form one body. Before formed Cryopump apparatus characterized by comprising a stepped shape cylinder. 2. A stepped portion between the thick cylinder flange-shaped base portion provided at the open end of the large diameter side first cylinder portion and the first cylinder portion and the small diameter side second cylinder portion. In a stepped tubular cylinder having a thick flange-shaped first stage portion provided and a thick flange-shaped second stage portion provided at the closed end of the second cylinder portion, a displacer for performing expansion cooling operation is provided. A cryopump device that reciprocates and has a reciprocating drive unit fixed to the base portion for performing the reciprocating movement, the base portion, the first cylinder portion, and the first cylinder portion.
The stage portion, the second cylinder portion, and the second stage portion are divided, and the stepped portion is integrated with either the first cylinder portion or the first stage portion, or the stepped portion. Each of the divided parts is integrated with the first cylinder and the first stage, and the base portion, the first cylinder portion, and the first portion
The step portion, the second cylinder portion, and the second stage portion are separately formed, and the stepped cylinder is integrally formed by hard brazing each of the separate bodies. Cryopump device.