JPS6256420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultra-low temperature refrigerator, and more specifically, it is capable of efficiently generating refrigeration of 10 K or less in a short time, and is applicable to a reverse Stirling cycle, a Gifford-McMahon cycle, etc. This relates to ultra-low temperature refrigerators, which are expanding.

According to the present invention, the compression space, the cooler, the first regenerator, the second regenerator, the third regenerator, and the regenerative heat exchanger are connected in sequence, and the first regenerator, the first expansion space, and the second regenerator are connected in sequence.
The regenerator and the second expansion space are connected to each other, the flow path of the regenerative heat exchanger and the third expansion space are connected to each other, and one end side of the space of the regenerative type heat exchanger is connected to the third regenerator through a one-way valve. A one-way valve is made to allow working gas to flow from the space of the regenerative heat exchanger toward the third regenerator, and the other end side of the space of the regenerative heat exchanger and the third expansion space are communicated via the throttle. The helium gas flowing in the space of the regenerative heat exchanger and the working gas flowing in the flow path of the regenerative heat exchanger exchange heat through the walls forming the flow path, thereby achieving a third expansion. in space
The present invention provides an ultra-low temperature refrigerator that efficiently generates refrigeration of 10K or less in a short time.

An embodiment of the present invention will be described based on FIGS. 1 and 2.

A compression space 3 formed by a compression cylinder 1 and a compression piston 2 is sequentially connected to a cooler 4 and a first regenerator 5.
and communicates with one end of the first expansion space 8 and the second regenerator 9 via communication pipes 6 and 7, respectively. The other end side of the second regenerator 9 is connected to the communication pipe 1
1 and 12, and communicate with one end side of the second expansion space 10 and the third regenerator 13, respectively. Said third
The other end of the regenerator 13 passes through communication pipes 14 and 34 and communicates with one end of the flow path 15a of the regenerative heat exchanger 15 and one end of the one-way valve 32, respectively.
The other end side of the flow path 15a is connected to the one-way valve 3 that communicates with the third expansion space 17 through the communication pipe 16.
The other end of 2 is connected to the regenerative heat exchanger 1 via a communication pipe 33.
It communicates with one end side of the space 15b of No. 5. The other end side of the space 15b of the regenerative heat exchanger 15 communicates with the third expansion space 17 through the communication pipe 20, the aperture 19, and the communication pipe 18 in this order.

The refrigeration circuit configured in this manner is filled with a refrigerant such as helium gas.

A rod 22 is connected to the compression piston 2,
Furthermore, on a part of the outer circumference of the compression piston 2,
A piston ring 23 is provided for gas sealing, and a seal 31 is also provided on a part of the outer wall of the rod 22 for gas sealing.

The first expansion space 8, the third expansion space 10, and the third expansion space 17 are each formed by an expansion cylinder 24 and an expansion piston 25, each having a two-stage convex shape. On the outer periphery of each stage of the expansion piston 25, piston rings 26, 27, and 28 are installed for sealing gas in the first, second, and third expansion spaces 8, 10, and 17. Also, the expansion piston 25 has a rod 2.
9 is connected, and a seal 30 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 advanced in phase by about 90 degrees from the compression piston 2.

The operation of the present invention will be explained first. 1 and 2 show an embodiment of the present invention, in which the working gas (helium gas, etc.) in the compression space 3 is compressed by the compression piston 2, then cooled by the cooler 4, and then transferred to the first regenerator 5. The air is further cooled, passes through the communication pipes 6 and 7, and flows into the first expansion space 8 and the second regenerator 9, respectively. The working gas that has entered the first expansion space 8 is expanded by the expansion piston 25, and its temperature drops and refrigeration occurs. By the way, the working gas that has flowed into the second regenerator 9 is further cooled, passes through the communication pipe 11 , passes through the second expansion space 10 and the communication pipe 12 , and flows into the third regenerator 13 . The working gas that has flowed into the second expansion space 10 is expanded by the expansion of the expansion piston 25,
Refrigeration is generated at a temperature lower than that of the first expansion space 8. The working gas that has flowed into the third regenerator 13 is further cooled and sequentially passes through the communication pipe 14 and the regenerative heat exchanger 1.
5 into the flow path 15a. The working gas flowing into the flow path 15a passes through the communication pipe 16 and enters the third expansion space 17 while cooling the helium gas into the space 15b of the heat exchanger 15 through the wall forming the flow path 15a.
flows into. The working gas that has flowed into the third expansion space 17 is expanded by the expansion piston 25 to generate refrigeration at a lower temperature than the second expansion space. Third
The working gas that has finished expanding in the expansion space 17 is compressed by the expansion piston 25, passes through the communication pipe 16, and flows into the flow path 15a of the regenerative heat exchanger 15. type heat exchanger 15
The helium gas in the space 15b flows into the third regenerator 13 through the communication pipe 14 while being cooled. The working gas that has flowed into the third regenerator 13 is warmed and
It flows into the second regenerator 9 through the communication pipe 12.
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 the communication pipe 7
It flows into the first regenerator 5 through. The working gas that has finished expanding in the first expansion space 8 is also transferred to the expansion piston 25.
is compressed, and flows into the first regenerator 5 through the communication pipe 9. The working gas that has flowed into the first regenerator 5 is
It is further heated and flows into the cooler 4, and then into the compression space 3.

By the way, when the pressure in the space 15b of the regenerative heat exchanger 15 is lower than the pressure in the third expansion space 17, the working gas in the third expansion space 17 is sequentially passed through the communication pipe 18 and the throttle 1.
9, it passes through the communication pipe 20 and sequentially flows into the space 15b. When the pressure in the space 15b of the regenerative heat exchanger 15 is higher than the pressure in the third regenerator 13, the gas in the space 15b is sequentially transferred to the communication pipe 33, the one-way valve 32, and the communication pipe 3.
4 and flows into the third regenerator 13. In this way, one cycle is formed. When this refrigeration cycle is repeated many times, the temperature of the working gas in each of the first expansion space 8, second expansion space 10, and third expansion space 17 gradually decreases, and the temperature of the working gas in the first expansion space 8 is about 100K, and the temperature of the working gas in the second expansion space 8 is about 100K, The expansion space is approximately 30K, the third expansion space is approximately 15K, and the heat storage type heat exchanger 15 is also approximately 15K.

By the way, the temperature of the regenerative heat exchanger 15 is about 15K.
Then, the third regenerator passes through the second regenerator 9 and the communication pipe 12.
The working gas that has flowed into the regenerator 13 further passes through the cooled communication pipe 14 and flows into the flow path 15a of the regenerator heat exchanger 15. The working gas flowing into the flow path 15a is further cooled by the helium gas flowing into the space 15b of the heat exchanger 15 through the wall forming the flow path 15a, and then passes through the communication pipe 16 into the third expansion space 17. Inflow. The working gas flowing into the third expansion space 17 is frozen at a temperature lower than 15K by the expansion of the expansion piston 25. The working gas that has finished expanding in the third expansion space 17 flows into the passage 15a of the regenerative heat exchanger 15 through the communication pipe 16 due to compression by the expansion piston 25.
The working gas that has flowed into the flow path 15a passes through the wall forming the flow path 15 to the space 15b of the regenerative heat exchanger 15.
It is heated by the helium gas flowing through the pipe 14 and flows into the third regenerator 13 through the communication pipe 14 . The working gas that has flowed into the third regenerator 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 3 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 manner, by repeating this refrigeration cycle many times, the first expansion space 8 generates refrigeration of approximately 70K, and the second expansion space 10 generates approximately 70K refrigeration. Generates 25K refrigeration. The working gas in the communication pipe 14 is about 15K, and the third expansion space 17 is about 15K.
Generates 4K freezing.

Next, when the operation of the refrigerator is stopped, the temperature of the space 15b of the regenerative heat exchanger 15 rises, and the temperature of the space 15b of the regenerative heat exchanger 15 increases.
The pressure becomes higher than the operating pressure of the safety valve 33. As a result, the helium gas in the space 15b passes through the communication pipe 32, the safety valve 33, and the communication pipe 34.
It flows into the regenerator 13, and the pressure in the space 15b is
Almost equal to the pressure of the regenerator.

According to the present invention, the space 1 of the regenerative heat exchanger 15
5b is communicated with the third expansion space 17 via the throttle, so even if the temperature of the regenerative heat exchanger falls,
A throttle 19 is provided in the space 15b of the regenerative heat exchanger 15.
The working gas for the third expansion space is supplied through.

As a result, the helium gas in the space 15b of the regenerative heat exchanger 15 and the helium gas in the flow path 15a are connected to each other through the wall forming the flow path 15a, utilizing the above-mentioned property of high heat capacity of helium gas (approximately 15 K or less). Since the heat is exchanged, the third expansion space 17
Efficiently generates refrigeration below 10K.

Since the third regenerator is provided between the regenerative heat exchanger 15 and the second regenerator, during the process in which the temperature of the third expansion space 17 decreases from room temperature to about 15K, the third regenerator
Cold storage material such as lead in the cold storage device 13 and the third cold storage device 1
As shown in the graph shown in Figure 3, the working gas (helium gas) flowing in the third expansion space 17 utilized heat exchange due to the large heat capacity of lead (approximately 15 K or more), and refrigeration occurred in the third expansion space 17. The regenerative heat exchanger 15 can be cooled down to about 15K in a short time using the working gas, and as a result, refrigeration of 10K or less can be achieved in a short time. One end side of the space 15b of the regenerative heat exchanger 15 and the third regenerator 13 are communicated via a one-way valve, and the one-way valve is configured such that the working gas flows from the space 15b toward the third regenerator 13. Therefore, when the pressure in the space 15b becomes higher than the pressure in the third regenerator 13, the helium gas in the space 15b passes through the one-way valve 13 to the third regenerator 13.
flows into. As a result, as the helium gas in the space 15b flows, heat transfer between the helium gas in the space 15b and the working gas in the flow path 15a is improved, and the working gas in the flow path 15a is sufficiently cooled. The efficiency of the container 15 can be improved.

The space 15b of the regenerative heat exchanger 15 is the one-way valve 3
The regenerator type heat exchanger 15 is connected to the third regenerator 13 via the regenerator 2, and is provided so that the working gas flows from the space 15b toward the third regenerator 13. As the temperature of the helium gas in the space 15b increases, the one-way valve 32
It flows into the third regenerator 13 in a short time. As a result, the pressure in the space 15b of the regenerative heat exchanger 15 does not rise abnormally, and there is no need to provide a safety valve or the like in the regenerative heat exchanger.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an ultra-low temperature refrigerator according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a one-way valve,
Figure 3 is a graph showing a comparison of the heat capacities per unit volume of 10at helium gas and lead balls. 15... Regenerative heat exchanger, 15a... Channel, 19...
Throttle, 32... one-way valve, 15b... space.

Claims (1)

[Claims] 1 The flow paths of the compression space, the cooler, the regenerator, and the regenerative heat exchanger are communicated in sequence, and the flow of the first regenerator and the first expansion space, the second regenerator and the second expansion space, and the regenerative heat exchanger is A one-way valve connects one end of the space surrounding the flow path of the regenerative heat exchanger and the third regenerator so that the working gas flows from the space to the third regenerator. The other end side of the space of the regenerative heat exchanger and the third expansion space are communicated with each other through a throttle, and the working gas flowing through the space of the regenerative heat exchanger and the third expansion space of the regenerative heat exchanger are connected to each other. An ultra-low temperature refrigerator characterized in that a working gas flowing through a flow path exchanges heat through a wall forming a flow path of a regenerative heat exchanger.