JPS5840454A - Cryogenic refrigerator - 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 The present invention relates to an ultra-low temperature refrigerator, and more specifically,
The present invention relates to an ultra-low temperature refrigerator which enables the following refrigeration to be efficiently generated in a short period of time with a simple mechanism, and which expands the range of applications such as reverse Stirling cycle or Gifford-McMahon cycle.

According to the present invention, the compression space, the cooler, the first regenerator, the second
The flow paths of the regenerator, the eighth regenerator, and the regenerative heat exchanger are connected in sequence, and the flow paths of the first regenerator and the first expansion space, the second regenerator and the second expansion space, and the regenerative heat exchanger are connected. A space that communicates the third expansion space and surrounds the outer wall side of the flow path of the regenerative heat exchanger, and an eighth
The expansion space is communicated through a throttle, and the working gas in the space of the regenerative heat exchanger and the working gas flowing through the flow path of the regenerative heat exchanger form a flow path of the regenerative heat exchanger. IO in the eighth expansion space by heat exchange through the wall
To provide an ultra-low temperature refrigeration trough pipe that efficiently generates refrigeration below K in a short time.

An embodiment of the present invention will be described based on FIGS. 1 and 2. A compression space 8 formed by a compression cylinder 1 and a compression piston 2 sequentially passes through a cooler 4, a first regenerator 5, and communicates with Via the tubes 6 and 7, a first expansion space 8. It communicates with one end of the second regenerator 9. Said second regenerator 9
The other end passes through communication pipes 11 and 12 and second expansion spaces respectively]0. It communicates with one end side of the eighth regenerator 18 .

The other end of the eighth regenerator 18 passes through the communication pipe 14 and communicates with one end of the flow path 15& of the regenerative heat exchanger 15. The other end of the flow path 151 communicates with the eighth expansion space 17 through the communication pipe 16 . The eighth expansion space 17 is sequentially connected to the communication pipe 18 . Aperture 19. A working gas such as helium gas is in the refrigeration circuit configured in this way, which communicates with the space 15b surrounding the outer wall side of the flow path 15a of the regenerative heat exchanger 15 through the communication pipe 20. is filled with refrigerant.

A rod 22 is connected to the compression piston 2, and a piston ring 23 for gas sealing is provided roughly on a part of the outer circumference of the compression piston 2.
A part of the outer wall of the first expansion space 8. Second expansion space 10.
The eighth expansion spaces 1.7 each have two convex expansion cylinders 24.7. A gap is formed by the expansion piston 25. On the outer periphery of each stage of the expansion piston z5, the 1.2
．． Piston rings 26, 27° 28 are provided for gas sealing of the three expansion spaces 8, 10, and 17. Further, a rod 29 is connected to the expansion piston 25, and a seal 80 for gas sealing is installed on a part of the outer wall of the rod. The rods 22 and 29 are connected to a reciprocating mechanism (for example, a crank mechanism), not shown, so that the expansion piston 25 is about 90 degrees ahead of the compression piston 2 in phase.

The present invention can also be applied to refrigerators such as the Gifford cycle, Gifford-McMahon cycle, and Tsurubay cycle that use switching valves.

To explain the operation of the present invention, the working gas (helium gas, etc.) in the compression space 8 is compressed by the compression piston 2, cooled by the cooler 4, passed through the first regenerator 5, and further cooled. It passes through the communication pipes 6 and 7 and flows into the first expansion space 8 and the second regenerator 9, respectively. 1st expansion air opening 8
The working gas that has entered is expanded by the expansion piston 25,
The temperature drops and freezing occurs. By the way, the working gas that has flowed into the second regenerator 9 is roughly cooled, passes through the communication pipe 11, passes through the second expansion space 10 and the communication pipe 12, and flows into the eighth regenerator 18, generating a low degree of refrigeration. . The working gas that has flowed into the eighth regenerator 13 is roughly cooled and then sequentially passed through the communication pipe 14.
．． It flows into the flow path 158 of the regenerative heat exchanger 15. Channel 1
The working gas that has flowed into the space 5m passes through the communication pipe 16 and flows into the eighth expansion space 17 while cooling the helium gas in the heat exchanger 15 chamber 15b through the wall forming the flow path 151.

The working gas that has flowed into the eighth expansion space 17 is transferred to the expansion piston 2.
5 to generate refrigeration at a lower temperature than the second expansion space. The working gas that has finished expanding in the eighth expansion space 17 is compressed by the expansion piston 25 into the communication pipe 16.
When it flows into the flow path 15m of the regenerative heat exchanger 15, the helium gas in the space 15b of the regenerative heat exchanger 15 is cooled through the wall forming the flow path 15m.
4 and flows into the eighth regenerator 18. 8th regenerator 18
The working gas that has flowed into the second regenerator 9 is heated and flows through the communication pipe 12 into the second regenerator 9 . Further, the working gas that has finished expanding in the second expansion space 10 also flows into the second regenerator 9 through the communication pipe 11 due to compression by the expansion piston 25. The working gas that has flowed into the second regenerator 9 is further warmed and flows into the first regenerator 5 through the communication pipe 7 . The working gas that has finished expanding in the first expansion space 8 also flows into the first regenerator 5 through the communication pipe 6 due to compression by the expansion piston 25. The working gas that has flowed into the first regenerator 5 is further warmed and flows into the cooler 4 and then into the compression space 8 .

By the way, when the temperature of the regenerative heat exchanger 15 decreases, the temperature of the helium gas in the space 15b of the regenerative heat exchanger 15 decreases, and the pressure in the space 15b decreases. When the pressure in the space 15b decreases, the working gas in the eighth expansion space 17 flows through the communication pipe 18.
．． It flows into the space 15b through the throttle 19 and the communication pipe 20, and the pressure in the space 15b becomes approximately equal to the average pressure of the refrigeration cycle.

Figure 2 (b) shows the change in pressure in this situation.
l indicates a change in the pressure in the eighth expansion space 17, which changes greatly due to the action of the compression piston 2 and the expansion piston 25, but the pressure in the space 15b of the regenerative heat exchanger is changed to P2 by the throttle 19.
As shown in the figure, the change in pressure becomes very small.

In this way, one cycle is formed. When this refrigeration cycle is repeated many times, the first expansion space 8, the second expansion space 1
0. The temperature of the working gas in each of the eighth expansion spaces 17 gradually decreases to about 100 K in the first expansion space 8, about 80 K in the second expansion space, and about 15 K in the eighth expansion space. 1
5. By the way, when the temperature of the regenerator type heat exchanger 15 reaches about 15K, the second regenerator 9. The working gas that has flowed into the third regenerator 13 through the communication pipe 12'ft is further cooled and passes through the communication pipe 1.
4 and flows into the flow path 15m of the regenerative heat exchanger 15.

The working gas flowing into the flow path 15 is further cooled by the helium gas in the space 15b of the heat exchanger 15 through the wall forming the flow path 15m1, and flows into the eighth expansion space 17 through the communication pipe 16. The working gas flowing into the third expansion space 17 is frozen at a lower temperature by the expansion piston 25 . The working gas that has finished expanding in the eighth expansion space 17 is compressed by the expansion piston 25 and passes through the communication pipe 16 into the flow path 15a of the regenerative heat exchanger 15.
flows into. The working gas that has flowed into the flow path 15m is
t - the space 15 of the regenerative heat exchanger 15 through the forming walls;
It is heated by the helium gas of b, and flows into the third regenerator 18 through the communication pipe 14. The working gas that has flowed into the eighth regenerator 18 is further warmed and flows into the second regenerator 9 through the communication pipe 12 . The working gas that has finished expanding in the second expansion space 10 and the first expansion space 8 returns to the compression space 8 by the same action as described above and completes one cycle. After the temperature of the regenerative heat exchanger 15 reaches approximately 15K in this way and if this refrigeration cycle is repeated many times, the first expansion space 8
generates refrigeration of about 70° and the second expansion space IO is about 2
5. Freezing occurs. The working gas in the communication pipe 14 is about 1:15, and the eighth expansion space 17 is about 4:1 frozen.

Next, when the operation of the refrigerator is stopped, the temperature in the space 15b of the regenerative heat exchanger 15 rises, and the pressure in the space 15b becomes higher than the pressure in the space forming the refrigeration cycle. As a result, the helium gas in the space 15b is transferred to the communication pipe 20. Aperture 19. It flows into the eighth expansion space 17 through the communication pipe 18 and enters the space 15.
The pressure at b is approximately equal to the pressure in the space forming the refrigeration cycle.

Figure 3 shows the heat capacity per unit volume of 1 Qat helium gas and a lead ball.It is clear that below 15, the heat capacity of helium gas is large, and above 15, the heat capacity per unit volume of the lead ball is large. This means that the heat capacity of helium gas is larger than that of helium gas.

From the above, according to the present invention, the space 15 of the regenerative heat exchanger 15
b is connected to the space forming the refrigeration cycle through the throttle, so even if the temperature of the regenerative heat exchanger 15 falls, the pressure in the space 15b of the regenerative heat exchanger 15 will remain the same as that of the eighth expansion space 8. Helium gas is supplied through a throttle 19 so as to maintain an intermediate pressure.

As a result, the helium gas in the space 15b of the regenerative heat exchanger 15 passes through the wall L7 forming the flow path 15ali to the flow path 15m.
The helium gas mentioned above (approximately 15
Since heat exchange is performed by utilizing the property of large heat capacity of (hereinafter referred to as), refrigeration below IOK can be efficiently generated in the eighth expansion space 17 with a simple mechanism.

Since the eighth regenerator is provided between the regenerative heat exchanger 15 and the second regenerator, the lead in the eighth regenerator 18 is removed during the process in which the temperature of the eighth expansion space 17 decreases from room temperature to about 15K. etc. and the working gas (helium gas) flowing in the eighth regenerator 18, as shown in the graph shown in FIG. The regenerative heat exchanger 15 can be cooled down to about 15K in a short time using the working gas that generated refrigeration in the third expansion space 17, and as a result, the following refrigeration can be achieved in a short time.

Since there are no moving parts such as one-way valves or safety valves in the low-temperature part, there is less risk of failure. 8th expansion space 1
7 and the space 15b of the regenerative heat exchanger are communicated only through the throttle, so the space 15b does not become a dead volume of the space forming the refrigeration cycle. As a result, the dead volume of the space forming the refrigeration cycle can be reduced,
Refrigerator efficiency improves. Space 1 of regenerative heat exchanger 15
5b forms a refrigeration cycle through the aperture, so
When the operation of the refrigerator is stopped, the helium gas in the space of the regenerative heat exchanger 15 flows through the throttle 19 into the space forming the refrigeration cycle as the temperature rises. As a result, the pressure in the space 15b of the regenerative heat exchanger 15 does not rise abnormally,
There is no need to provide a safety valve or the like to the regenerative heat exchanger.

FIG. 4 shows another embodiment of the invention. Third regenerator 1
8 and the space 15b of the regenerative heat exchanger 15 through a communication pipe 46. Aperture 32. FIG. 5 shows another embodiment of the present invention, in which communication is provided through a communication tube 83 and the other configurations are the same as in FIG. 1. In the middle of the flow path 15m of the regenerative heat exchanger 15 and the space 1
5b is sequentially connected to the communication pipe 84. Aperture 85. They are communicated through a communication tube 36, and the other configurations are the same as in FIG.

The operations in FIGS. 4 and 5 are similar to those in FIG. 1.

FIG. 6 shows another embodiment of the invention. Pahua space 45
The communication pipe 8 is sequentially connected between the space 15b of the regenerative heat exchanger 15 and
7. Communication pipe 38 wrapped around the outer wall of the 111th cooler 5. Communication pipe 89. Communication pipe 40 wrapped around the outer wall of the second regenerator 9
．． A communication pipe 441, a communication pipe 42 wrapped around the outer wall of the third regenerator 13. Communication pipe 48. Aperture 44. The communication pipe 45 is then brought into communication, and the other configurations are the same as in FIG. 1.

To explain the effect shown in FIG. 6, when the pressure in the space 15b of the regenerative heat exchanger 15 is lower than the pressure in the buffer space 45, the working gas in the buffer space 45 passes through the communication pipe 87.
It flows into the communication pipe 88. The working gas flowing into the communication pipe 88 is cooled by the first regenerator 5, passes through the communication pipe 89,
It flows into the communication pipe 40. The working gas that has flowed into the communication pipe 40 is cooled by the second regenerator 9 and flows into the communication pipe 42 through the communication pipe 41 . The working gas that has flowed into the communication pipe 42 is cooled by the eighth regenerator 42, and is sequentially transferred to the communication pipe 43.
It flows into the space 15b of the regenerative heat exchanger 15 through the 44° throttle communication pipe 45.

When the pressure in the buffer space 45 is lower than the pressure in the space 15b of the regenerative heat exchanger 15, the regenerative heat exchanger-g%15
The helium gas in the space 15b is sequentially transferred to the communication pipe 45. Aperture 44. It flows into the communication pipe 42 through the communication pipe 48. The working gas that has flowed into the communication pipe 42 is warmed by the third regenerator 13, and the working gas that has expanded into the 0 communication pipe 40, which flows into the communication pipe 40 through the communication pipe 41, is further warmed by the second regenerator. It passes through the communication pipe 39 and flows into the communication pipe 38 . The working gas flowing into the communication pipe 38 is further warmed by the first regenerator and passes through the communication pipe 87 to the buffer space 45.
The other effects are exactly similar to the implementation shown in FIG.

Similar to the embodiment shown in Fig. 1, the embodiments shown in Figs. 4 to 6 have the same effect that freezing of less than IOK occurs in the 8th expansion space in an extremely short period of time, and in the regenerative heat exchanger. It is also possible to provide an extremely efficient ultra-low temperature refrigerator, since there is no need to use a safety valve to throw snow.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of an ultra-low temperature refrigerator according to an embodiment of the present invention, Fig. 2(a) is an enlarged sectional view of the constriction part, Fig. 2(Φ)
is a graph showing changes in the working gas pressure (Pl) in the eighth expansion space 16 and the working gas pressure (P2) in the space 15b in the regenerative heat exchanger. A graph showing a comparison of the heat capacities of (working gas) and lead, and FIGS. 4 to 6 are schematic sectional views showing other modified embodiments of the present invention. 15: Regenerative heat exchanger, 15a: Flow path, 15b: Space inside the heat exchanger, 19: Aperture. Patent applicant Aisin Seiki Co., Ltd. Representative Reio Nakai and @3@241-

Claims (1)

[Claims] A space in which a compression space, a cooler, a regenerator, a regenerative heat exchanger, and an expansion space are sequentially communicated, and a space surrounding the outer wall side of the flow path of the regenerative heat exchanger forms a refrigeration cycle. communicating through a throttle, and flowing working gas (helium gas) between the space of the regenerative heat exchanger and the space forming the refrigeration cycle through the throttle;
heat exchange between the working gas flowing through the flow path of the regenerative heat exchanger and the helium gas in the space of the regenerative heat exchanger through a wall forming the flow path. An ultra-low temperature refrigerator.