JPS60122869A - Heat exchanger for cryogenic refrigerator system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a heat exchanger for an ultra-low temperature refrigerator system that obtains refrigeration as described by Stirling, Gifford-McMahon et al. Used for cooling the adsorption panels of Talio pumps.

[Prior art]

A plurality of refrigerators are arranged in which a compression space, a cooler, a regenerator, and an expansion space are sequentially communicated, and a heat exchanger shared by each of the refrigerators is provided between the regenerator and the expansion space. Figure 1 shows an ultra-low temperature refrigerator system in which a countercurrent heat exchanger is formed. Such types of ultra-low temperature refrigerator systems are known and are described in Japanese Patent Publication No. 43-10942 and Utility Model Application No. 56-88059. The ultra-low temperature refrigerator system will be explained based on FIG. 1. The compression space 3 formed by the compression cylinder 1 and the compression piston 2 is connected to a cooler 4. It communicates with the first expansion space 7 and the heat exchanger 6 through the M cooler 5, and the heat exchanger 6 further communicates with the second expansion space 8. In this way, the compressed space 3. Cooler 4. Regenerator 5, first expansion space 7. A refrigeration circuit is comprised of the heat exchanger 6 and the second expansion space 8, and helium gas is sealed in the refrigeration circuit as a working gas.

A rod 14 is connected to the compression piston 2, and a seal 9 for gas sealing is provided on a part of the outer circumference of the compression piston 2, and a seal 9 for gas sealing is also provided on a part of the outer wall of the rod 14. Seal E0 is installed for this purpose.

First expansion space7. The second expansion space 8 has a convex expansion cylinder 17. It is formed by an expansion piston 16.

On the outer periphery of each stage of the expansion piston 16, seals 11, 12 are installed for sealing gas in the first and second expansion spaces 7, 8. Further, a rod 15 is connected to the expansion piston 16, and a seal 13 for gas sealing is installed on a part of the outer wall of the rod 15. Rod 14. 'L
5 is a reciprocating drive mechanism (for example, a crank) not shown.
Refrigerator A and refrigerator B, which are connected to each other and shown by broken lines, are
It is driven with a phase difference of approximately 180 degrees (that is, it moves with a phase difference of approximately 180 degrees with respect to the expansion piston 16 and compression piston 2 of refrigerator A).

The function of refrigerator A will be explained.

After the working gas (helium gas) in the compression space 3 is compressed by the compression piston 2 , it is cooled to about 20 K in the cooler 4 and flows into the regenerator 5 . The working gas that has entered the regenerator 5 is further cooled and flows into the first expansion space 7 and the heat exchanger 6. The working gas entering the first expansion space 7 is expanded by the expansion piston 16 to produce refrigeration at a temperature of approx. By the way, the working gas that has flowed into the heat exchanger 6 is cooled by the working gas flowing in the heat exchanger 6 of the refrigerator B in the direction of the regenerator 5, flows into the second expansion space 8, and is expanded by the expansion piston 16. , producing refrigeration at a temperature of approx. When the working gas that has finished expanding in the second expansion space 8 flows into the heat exchanger 6 due to compression by the expansion piston 16, it flows inside the heat exchanger 6 of the refrigerator B in the direction of the second expansion space 8. The working gas is given heat, the temperature is raised, and the working gas flows into the regenerator 5. The working gas that has finished expanding in the first expansion space 7 flows into the regenerator 5 due to compression by the expansion piston 16 . The working gas that has flowed into the regenerator 5 is warmed and flows into the cooler 4 and then into the compression space 3 . In this way, the refrigerator A forms the (1) cycle.

The operation of refrigerator B is similar to refrigerator A except that it is driven with a phase difference of approximately 180 degrees from refrigerator A.

Heat exchanger 6 used in the ultra-low temperature refrigerator system shown in Figure 1
Regarding this, Japanese Patent Publication No. 43-10942 does not show any specific structure, but Utility Model Application Publication No. 56-88059 describes the structure shown in Figures 2, 3, and 4. .

Hereinafter, a conventional heat exchanger for an ultra-low temperature refrigerator will be explained based on FIG. 2. The plate 101 has communication holes 102,
103, and a communicating hole 102. , L03 are connected to the regenerators 5 of the refrigerators A and B, respectively. Plate 101
A member 104 (see Fig. 3) with poor thermal conductivity is fixed airtightly, and a member 105 (see Fig. 4) with good thermal conductivity having a large number of holes is placed on top of the member 104 in an airtight manner. Fixed - In this way, the members 104 and 105 are alternately stacked and fixed in an airtight manner, and a plate 106 having communication holes 107 and 108 is fixed in an airtight manner on top of the last member 104. The communication holes 107 and 108 communicate with the second expansion spaces 8 of the refrigerators A and B, respectively.

[Problems in the prior art and their technical analysis] In the conventional heat exchanger 6 shown in FIG. FRP such as fiber was used, and the two were bonded together with an epoxy adhesive.

Generally, it is difficult to obtain airtightness for gases with small mass numbers such as helium, and in the structure shown in Figure 2, there are usually about 500 to 1000 bonding points, and it is difficult to obtain airtightness at all bonding points. is extremely difficult. Further, even if airtightness is initially obtained, the airtightness is frequently lost during use because the refrigerator undergoes a thermal cycle from room temperature to 4K each time the refrigerator is started or stopped.

Therefore, the member 104 with poor heat conduction and the member 1 with good heat conduction
The working gas boundary walls of refrigerator A and refrigerator B, which are formed by 05, communicate with each other without losing airtightness.

Normally, refrigerator A and refrigerator B have a phase difference of 180 degrees, so for example, when the pressure of the working gas in refrigerator A is the highest, the pressure of the working gas in refrigerator B is the lowest. ,
Further, when the pressure of the working gas of the refrigerator A is the lowest, the pressure of the working gas of the refrigerator B is the highest. For this reason, refrigerator A
When the boundary wall of the working gas of refrigerator A and refrigerator B is in communication, the difference in the pressure of the working gas of refrigerator A and refrigerator 11B becomes small, and the maximum pressure and minimum pressure of each refrigerator A and B become close, Therefore, the compression ratio becomes smaller and the refrigeration output decreases.

In addition, holes in the member 105 with good thermal conductivity can be made by photo-etching with appropriate sound, but since it is impossible to make the diameter of the holes smaller than the thickness of the plate, it is not possible to make too many holes (therefore, the heat transfer area is As a result, the heat exchange efficiency of the heat exchanger 6 decreases, and this inefficiency is compensated for by the refrigeration output, resulting in a decrease in the effective refrigeration output.

[Technical issues]

Therefore, the technical object of the present invention is to easily obtain reliable airtightness at the boundary between the working gas of the refrigerator A and the working gas of the refrigerator B in the heat exchanger 6.

Moreover, the technical object of the present invention is to increase the heat transfer area of the heat exchanger 6.

[Technical means]

The technical means taken to achieve the above technical problem is to provide a thin side wall penetrating in the flow direction of the working gas inside the heat exchanger 6, and to contact both sides of this side wall in the flow direction of the working gas. The method is to stack the wire mesh in a vertical position and to diffusion bond the side wall and the wire mesh. [Function of technical means] The above technical means works as follows. When the working gas of the refrigerator A flows from the first regenerator 5 to the heat exchanger 6, the working gas of the refrigerator A flows through the wire mesh on the refrigerator A side, the side wall, and the wire mesh on the refrigerator B side. It is cooled by the working gas flowing in the heat exchanger 6 of B in the direction of the regenerator 5, and flows into the second expansion space. Conversely, when the working gas of the refrigerator A flows into the heat exchanger 6 from the second expansion space, the working gas of the refrigerator A flows through the wire mesh on the refrigerator A side, the side wall, and the wire mesh on the refrigerator B side. It is heated by the working gas flowing in the heat exchanger 6 of the refrigerator B in the direction of the second expansion space, and flows into the regenerator 5.

[Special effects caused by the invention]

The present invention produces the following unique effects. Since the side wall penetrates in the flow direction of the working gas and separates the working gas of refrigerator A and the working gas of refrigerator B, airtightness between the two can be easily achieved, and it is also possible to easily maintain airtightness during operation or stoppage. The airtightness will not be lost due to thermal cycling.

In addition, wire mesh is usually made of materials such as tough pitch copper, which has good thermal conductivity.
Since a wire diameter of 0.11 m; pitch of 0.25 mm can be easily obtained, the heat transfer area is several times larger than that of a conventional perforated plate (Fig. 4, member 105 with good heat conduction). be able to.

In this type of heat exchanger 6, unlike the conventional heat exchanger 6, a thermal insulator (Fig. 3, member 10 with poor thermal conductivity) is used.
4) is not used, there is a concern that heat may enter from the high temperature section of the heat exchanger 6 to the low temperature section due to conduction. There are two possibilities for this heat intrusion: conduction through the side walls and conduction through the laminated wire mesh.

First, heat intrusion due to heat conduction through the side walls can be reduced by making the wall thickness of the side walls as thin as possible, and at the same time, the heat exchange efficiency between the working gas of refrigerator A and the working gas of refrigerator B can be improved. I can do it. Moreover, even if the side walls are made as thin as possible, if the side walls are made of a material with high thermal conductivity (such as tough pitch copper), the heat exchange efficiency between the working gas of refrigerator A and the working gas of refrigerator B is good. However, the amount of heat entering from the high temperature section to the low temperature section of the heat exchanger 6 becomes too large. On the contrary, the material of the side wall is a material with low thermal conductivity (SU S 30
-4, etc.), the amount of heat intrusion from the high-temperature section to the low-temperature section of the heat exchanger 6 can be almost completely suppressed;
The heat exchange efficiency between the working gas of the refrigerator B and the working gas of the refrigerator B is considerably reduced. Therefore, if the material of the side wall is a material with medium thermal conductivity (phosphorus-deoxidized copper, industrially pure titanium, etc.),
The heat exchange efficiency between the working gas of the refrigerator A and the working gas of the refrigerator B can be made sufficiently high while sufficiently suppressing the amount of heat intrusion from the high temperature part to the low temperature part of the heat exchanger 6.

Next, pass through the laminated wire mesh (for heat intrusion due to thermal conduction,
When wire mesh is laminated, the contact area is very small, and therefore the amount of heat penetration is also very small.

[First Example] Hereinafter, a first example showing a specific example of the above technical means will be described with reference to FIGS. 5 and 6. The communication hole 107 is connected to the second expansion space 8 on the refrigerator A side, and the communication hole 102 is connected to the regenerator 5 on the refrigerator A side. Communication hole 1
08 is connected to the second expansion space 8 on the side of the refrigerator B, and is connected to the communication hole 1
03 is connected to the regenerator 5 on the refrigerator B side. The side wall 202 has the shape of a thin circular tube and passes through the top and bottom of the heat exchanger 6 . Wire meshes 204, 2 and 5 are laminated in contact with both the inner and outer surfaces of the side wall 202, and the side wall 202 and the wire meshes 204 and 205 are diffusion bonded. The housing 203 forms an outer wall of the heat exchanger 6. Cap 201 forms a flow path for working gas to the refrigerator.

The operation of the embodiment shown in FIGS. 5 and 6 will be explained. Working gas for the refrigerator flows from the regenerator 5 through the communication hole 102 and the cap 201 into the laminated portion of the wire mesh 204. At the same time, the working gas of the refrigerator B flows from the second expansion space 8 through the communication hole 108 into the laminated portion of the wire mesh 205. At this time, the temperature of the working gas of refrigerator A is about IOK,
Since the temperature of the working gas of the refrigerator B is about 4°C, heat exchange is performed efficiently through the wire meshes 204 and 205 and the side wall 202. The working gas of the refrigerator A is cooled and flows into the second expansion space 8 through the cap 201 and the communication hole 107. The working gas of refrigerator B is heated and passes through communication hole 1.
03 and flows into the regenerator 5.

The working gas of the refrigerator A flows from the second expansion space 8 to the communication hole 107.
．． It passes through the cap 201 and flows into the laminated portion of the wire mesh 204. At the same time, working gas from refrigerator B flows from regenerator 5 through communication hole 103 into the laminated portion of wire mesh 205 . At this time, the temperature of the working gas of refrigerator A is about 4, and the temperature of the working gas of refrigerator B is about IOK, so the wire mesh 2
4, 205 and the side wall 202, heat exchange is performed efficiently. The working gas of refrigerator A is heated and flows into regenerator 5 through cap 201 and communication hole 102 . The working gas of the refrigerator B is cooled and flows into the second expansion space 8 through the communication hole 108.

[Second Embodiment] Next, a second embodiment showing a specific example of the technical means of the present invention will be described with reference to FIGS. 7 and 8. Communication hole 1
07 is connected to the second expansion space 8 on the side of the refrigerator A, and is connected to the communication hole 1
02 is connected to the regenerator 5 on the refrigerator A side. Communication hole 108
is connected to the second expansion space 8 on the side of the refrigerator B, and the communication hole 103
is connected to the regenerator 5 on the refrigerator B side. The side wall 302 has the shape of four thin-walled circular tubes and passes through the top and bottom of the heat exchanger 6. In contact with both the inner and outer surfaces of the side wall 302, a wire mesh 304.3
05 are laminated, and the side wall 302 and wire mesh 304 and 305 are diffusion bonded. The housing 303 forms the outer wall of the heat exchanger 6. The cap 301 forms a flow path for the working gas of the refrigerator A.

The operation of the embodiment shown in FIGS. 7 and 8 will be explained. Working gas from the refrigerator A flows from the regenerator 5 through the communication hole 102 and the cap 301 into the laminated portion of the wire mesh 304 . At the same time, the working gas of the refrigerator B flows from the second expansion space 8 through the communication hole 108 into the laminated portion of the wire mesh 305. At this time, the temperature of the working gas of refrigerator A is about IOK,
Since the temperature of the working gas of the refrigerator B is about 4°C, heat exchange is performed efficiently through the wire meshes 304 and 305 and the side wall 302. The working gas of the refrigerator A is cooled and passes through the cap 301 and the communication hole 107 to the second expansion space 8.
flows into. The working gas of the refrigerator B is heated and flows into the regenerator 5 through the communication hole 103.

The working gas of the refrigerator A flows from the second expansion space 8 to the communication hole 107.
．． It passes through the cap 301 and flows into the laminated portion of the wire mesh 304. At the same time, working gas from the refrigerator B passes through the communication hole 103 from the regenerator 5 and flows into the laminated portion of the wire mesh 3.degree.5. At this time, the temperature of the working gas to the refrigerator is about 4, and the temperature of the working gas of the refrigerator B is about IOK, so the wire mesh 30
4, 305 and the side wall 302, heat exchange is performed efficiently. The working gas of the refrigerator A is heated and flows into the regenerator 5 through the cap 301 and the communication hole 102 . The working gas of the refrigerator B is cooled and flows into the second expansion space 8 through the communication hole 108.

[Third Embodiment] Next, a third embodiment illustrating an example of the technical means of the present invention will be described with reference to FIG. 9.

A compression space 3 formed by the compression cylinder 1 and the compression piston 2 communicates with a cooler 4, a heat exchanger 6, and an expansion space 8. In this way, the compressed space 3. Cooler 4. A refrigeration circuit is composed of a heat exchanger 6 and an expansion space 8,
Helium gas is sealed in the refrigeration circuit as a working gas. A rod 14 is connected to the compression piston 2, and a seal 9 for gas sealing is provided on a part of the outer wall of the compression piston 2, and a gas seal is also provided on a part of the outer wall of the rod 14. A seal 10 is installed for this purpose.

The expansion space 8 is an expansion cylinder 17. It is formed by an expansion piston 16. A seal 12 is installed on the outer periphery of the expansion piston 16 for sealing gas in the expansion space 8 . Further, a rod 15 is connected to the expansion piston 16, and a seal 13 for gas sealing is installed on a part of the outer wall of the rod 15. The rods 14 and 15 are connected to a reciprocating drive mechanism (for example, a crank) not shown, and the refrigerators A and B shown in broken lines are
It is driven with a phase difference of 0 degrees (that is, it moves with a phase difference of approximately 180 degrees with respect to the expansion piston I6 and compression piston 2 of refrigerator A).

The function of refrigerator A will be explained.

After the working gas (helium gas) in the compression space 3 is compressed by the compression piston 2 , it is cooled to about 20 K in the cooler 4 and flows into the heat exchanger 6 . The working gas that has flowed into the heat exchanger 6 is cooled by the working gas flowing in the direction of cooling a4 within the heat exchanger 6 of the refrigerator B, and flows into the expansion space 8.
It is expanded by the expansion piston 6 to produce refrigeration at a temperature of approx. When the working gas that has finished expanding in the expansion space 8 flows into the heat exchanger 6 due to the compression of the expansion piston 16, the working gas flowing in the heat exchanger 6 of the refrigerator B in the direction of the expansion space 8 causes , is given heat and its temperature is increased, and flows into the cooler 4 and further into the compression space 3.

In this way, refrigerator A forms one cycle.

The operation of refrigerator B is similar to refrigerator A except that it is driven with a phase difference of approximately 180 degrees from refrigerator A.

The heat exchanger 6 of the present invention (for example, the first embodiment shown in FIG. 5, the seventh embodiment shown in FIG.
The second embodiment shown in the figure) can be used.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an ultra-low temperature refrigerator system, FIG. 2 is an explanatory sectional view showing a conventional heat exchanger, FIG. 3 is an explanatory plan view of the member 104 in FIG. FIG. 5 is an explanatory plan view of the member 105 in the figure; FIG. 5 is an explanatory cross-sectional view of the first embodiment showing one specific example of the heat exchanger of the present invention;
The figure is a Vl-Vl cross-sectional view of FIG. 5, and FIG. 7 is an explanatory cross-sectional view of a second embodiment showing an integrated example of the heat exchanger of the present invention.
FIG. 8 is a cross-sectional view taken along the line ■-■ of FIG. 7, and FIG. 9 is an explanatory diagram showing an ultra-low temperature refrigerator system different from that shown in FIG. 1, in which the heat exchanger of the present invention can be used. ... Compression space, 4... Cooler, 5... Regenerator, 8... Expansion space, A, B... Refrigerator, 6... Heat exchanger, 202,
302... side wall, 204, 205, 304, 305.
... Wire mesh patent applicant 1 Iren #1 Tan stock government company representative Reio Nakai 21st! l No. 31 @4-

Claims (2)

[Claims] (1) A plurality of refrigerators are arranged in which a compression space, a cooling layer, a regenerator, and an expansion space are sequentially communicated, and the refrigerators mutually share heat exchange between the regenerator and the expansion space. In an ultra-low temperature refrigerator system in which a heat exchanger is provided to form an I-type heat exchanger, a side wall of the heat exchanger penetrates in the flow direction of the working gas of each of the refrigerators, and is in contact with both sides of the side wall. A heat exchanger for an ultra-low temperature refrigerator system, which is constructed by stacking wire meshes in a position perpendicular to the flow direction of working gas and joining the side walls and the wire meshes together. (2) A plurality of refrigerators are arranged in which a compression space, a cooler, and an expansion space are sequentially communicated, and a heat exchanger shared by the refrigerators is provided between the cooler and the expansion space. In an ultra-low temperature refrigerator system in which a countercurrent heat exchanger is formed, the heat exchanger has a side wall that penetrates in the flow direction of the working gas of each of the refrigerators, and is in contact with both sides of the side wall to control the flow of the working gas. A heat exchanger for an ultra-low temperature refrigerator system constructed by stacking wire meshes in a position perpendicular to the direction and joining the side walls and the wire meshes.