JPS59157451A - Stirling cycle 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 (Object of the Invention) The present invention provides a refrigerating machine having a heat radiator and a regenerator between a variable compression space and a variable multi-stage expansion space. IK
The following pertains to obtaining cryogenic refrigeration.

(Field of Application of the Present Invention) A schooling vehicle cryocooler is attached to a cryostat filled with liquid helium, and re-liquefies helium vapor that evaporates due to the heat that enters the cryostat. When the amount of wealth.

It is something that can be held constant.

The present invention is indispensable for cooling systems that are required to maintain superconducting magnets, dicocefson elements, skid elements, etc. cooled with liquid helium at extremely low temperatures.

(Prior Art) Such cryogenic refrigeration has advances in conventional technology.
ry-ogenic Engineering Vol.
ume 16 (1'roceedinHsof th
e 1970 Cryoge'nic Engine
ering Conference-ence The Uni
versity of Col1orado Bould
er+Colorado June 17-19.19
Triple-expansio shown in 70)
n Stirring-Cycle Refrtgera
- As in Tor, the expansion cylinder 105V accommodates the expansion piston 106, and the first expansion space 107 (
Extra Expansion 5pace 1)
+Second expansion arch length space (lExtra t!xpans
ion 5pace 2 ) + and the third expansion space (
lExt, ra P, expansion 5pace
3) has a "digital configuration. This is shown in the drawing as follows.

FIG. 1 is a block diagram of such a cryogenic refrigerator. 1st
In the figure, 101 is a compression cylinder 10, and the compression cylinder 10 is slidably equipped with a compression piston 102. No. 103 is a compression space, and a Jk heater 104 is provided above the compression cylinder 101 and communicates with the compression space 103. 105L is an expansion cylinder communicating with the above-mentioned discharge cylinder 104.

A sliding expansion screw 106 is provided inside. The expansion piston 106 and the expansion cylinder 10
5 is the first expansion space 107. Second expansion space 108. Third
An expansion space 109 is formed. The expansion piston 10
6 is a flow path 106a through which a refrigerant such as helium gas flows;
Regenerator 1.06b, flow path 106C, first regenerator 106
d, the flow path 106e, the third regenerator 106f, and the flow path 106g are provided so as to communicate with each other in this order. The first regenerator 106b communicates with the first expansion space 107, the second regenerator 106d communicates with the second expansion space 108, and the flow path 106g communicates with the third expansion space. A radiation shield plate 110 is fixed to the outer surface of the expansion cylinder 105 in a portion forming the first expansion space 107 . The refrigerant in the compression space 103 is compressed by the upward movement of the compression piston 102, and the refrigerant is compressed by the upward movement of the compression piston 102.
3, and sequentially the flow path 1osa, the first regenerator 1
06b, flow path 106 C, 2nd M cold mold 106d, flow path 1
06e, the third regenerator 106f, and flows into the flow path 106g. The first regenerator 106b, the second regenerator 10
6d, the refrigerant that has flowed into the third regenerator 106f is sequentially cooled and its temperature is lowered. 1st F+? Cooler 10G +
) to the first expansion space 107. from the second regenerator 106d to the second expansion space 108. Then, the refrigerant that has passed through the flow path 106g from the third regenerator 106f and flowed into the third expansion space 109 undergoes approximately isothermal expansion due to the downward movement of the IIδ dielectric piston 106. Space 107°10
8. Refrigeration occurs at lower temperatures in sequence within 109. The refrigeration generated in the first expansion space 107 is transferred to the expansion cylinder 105.
The energy is used to absorb heat that enters from the room temperature part of the expansion piston 106 through solid conduction, radiation heat that enters from the room temperature part through the radiation shield plate 110, and further heat loss that occurs due to inefficiency of the first regenerator 106b. It will be done.

(Problems and technical analysis of conventional technology) In the conventional cryogenic refrigerator, the temperature of the refrigerant (helium gas) in the third expansion space 109 reaches approximately 7.8 or more.
The evaporated helium gas in the Flyos foot, which cools superconducting magnets, Josephson elements, Schitzer elements, etc., reaches the m! ! Since the temperature does not reach s, IK or below, it becomes impossible to maintain a constant level of liquid helium at all times, and furthermore, it becomes impossible to cool superconducting magnets, Josephson pilgrims, skit elements, etc. at extremely low temperatures for long periods of time. The problem arises that it is no longer possible.

This problem arises because the refrigerant (helium gas) deviates from an ideal gas by as much as 1 J at a temperature of approximately 15°C or lower, so in order to generate refrigeration of approximately 12°C or lower in the third expansion space 109, the refrigerant (helium gas) must be The average pressure (for example, 3.5 kg/I) of helium gas must be lowered, and as a result,
When the refrigerant gas in the first expansion space 107 is at a temperature of approximately 70°C, the amount of refrigeration decreases, so that the expansion cylinder 105. Conductive heat that travels through the expansion piston 106 and enters the first expansion space 07, heat that travels through the radiation shield plate 110 due to radiation from the room temperature section and is used in the first expansion space 107, and non-heat of the first regenerator 106b. The first expansion space 10 due to heat loss generated due to efficiency.
7, the temperature of the refrigerant in the fs2 expansion space 108 also rises, and as a result, the temperature of the refrigerant in the third expansion space 109 increases.
This is because the temperature of the refrigerant inside the tank is about 7.8 or less.

In order to obtain refrigeration of approximately 70°C with as little as 1 quenching power in the first expansion space 107, a refrigerant (helium gas) is used.
A good average pressure is approximately 20 kg/cJ, and the lower the average pressure, the greater the power consumption. In this conventional device, in order to increase the approximately 70 K refrigeration generated in the first expansion space due to the requirement to reduce power consumption, the volume of the compression space and the volume of the first expansion space are It is not possible to increase 1 (Prior art) As a device that improves the drawbacks of the cryogenic refrigerator, there is a reversible refrigerator shown in Japanese Patent Publication No. 11190/1983, which is shown in Fig. 2. The explanation based on this is as follows.

The receiving air pipe 5 is provided with a heat conducting ring 1 at a predetermined position on the outer surface of the cylinder 10.
The pipe 5 is thermally connected to a predetermined position on the outer surface of the cylinder IC via a heat conducting ring 12, and a predetermined portion of the wall of the cylinder 1c is precooled.

(Problems and technical analysis of conventional technology) Therefore, the cylinder IC must be cooled at two locations, which complicates the equipment configuration.

The problem is that the cylinder IC does not cause refrigeration between the cylinder chamber 1℃ and the cylinder chamber 1℃ and does not have any 7 chambers, so the heat conduction tube 1
This is because the heat generated by one tatami mat from the normal temperature section must be absorbed by the refrigerant in the vent pipes 5'' and 5 through the cylinder IC walls through the 2'' and 12''.

(Technical Problem) In order to obtain the following refrigeration in 5.1, the present invention provides a refrigerant (helium gas) at a low average pressure in a refrigerator having a radiator and a regenerator between a variable compression space and a variable expansion space. without increasing the volumes of the compression and expansion spaces.
In addition, it is possible to save the equipment configuration and generate the following refrigeration with less power consumption.

(Technical means) The technical means taken to solve the steam technical problem is to install a pre-cooling refrigerator 13 on the outer surface of the first regenerator cylinder 12a and the first expansion cylinder 12b of the multi-stage expansion cylinder 12 to the main refrigeration chamber. The cold head a 51 is fixed to the ground surface of the cold head 51, and the first radiation shield plate 31 is secured to the soil surface of the cold head 51 with a large number of bolts 52 so as to be housed inside the second expansion cylinder 120 and the second radiation seal l''+1i26. Fix the average pressure of the main refrigerator (helium gas) to the optimum pressure that produces refrigeration below 5.1 in the fourth expansion space 17, and set the average pressure of the refrigerant (helium gas) of the pre-cooling refrigerator to The purpose is to increase the pressure in the first expansion space to an optimal pressure that generates refrigeration of approximately 70 K.

[Effect of technical means]

The above technical means works as follows. That is, the conduction heat transmitted through the first regenerator gate 112a from the room temperature section and the radiation from the room temperature section cause the first radiation shield plate 31 to
The radiant heat increases in the filtrate, and from the refrigerant (helium gas) in the first expansion space 14, the 1111th expansion cylinder 1
The heat loss generated due to the inefficiency of the first cooler 13 that is transmitted through one wall of 2h is reduced by the less power consumption of the precooler B at the cold head 1°51 of the precooler, which is filled with refrigerant at the optimal pressure. , can be absorbed.

The second expansion cylinder 12c from the vicinity of the first expansion space 14
The heat that infiltrates the second expansion space 15 through the walls of the second
The heat absorbed by the refrigeration generated by the refrigerant (- lium gas) in the expansion space 15 and transmitted through the wall of the third expansion cylinder 12d near the second expansion space 15 and infiltrated into the third expansion space 16 is absorbed by the third expansion cylinder 12d. Almost no heat enters the fourth expansion space 17 because it is absorbed by the refrigeration generated by the refrigerant (helium gas) in the expansion space 16 .

Therefore, the temperature of the refrigerant in the first expansion space 14 can be lowered without increasing the volume of the compression space 25 and the volume of the first expansion space 14 to the main refrigerator.
The temperature of the refrigerant (helium gas) between the expansion chambers 15 and 16 can be lowered, and as a result, refrigeration in the fourth expansion space 17 can be performed with less power from the main refrigeration and pre-cooling refrigerators, without complicating the equipment configuration. , about 5. Freezing occurs below IK.

[Special effects produced by the present invention]

The present invention produces the following unique effects. That is, since the first regenerator cylinder 123 and the first expansion cylinder 12b are cooled by the cold head 51 of the pre-cooling refrigerator B, which is filled with refrigerant at an optimal pressure, the inside of the first expansion space 14 is cooled in a short time. The refrigerant temperature of the second.
Secondly, the temperature of the refrigerant in the fourth expansion space 15, 16.17 is also
Steady state is reached in a short time.

Since the temperature of the first radiation shield plate 31 is approximately equal to and lower than the temperature of the cold head of the pre-cooling refrigerator B,
From the first radiation shield plate 31 to the second radiation shield plate 2
6 and the radiant heat that enters the second expansion cylinder 12c is
The volume of the second expansion space 15 becomes smaller.

(Example) Hereinafter, an example showing a specific example of the above technical means will be described.

In the example shown in FIG. 3, a piston ring 2 is installed in a groove on the outer periphery of a compression piston 1, and a compression piston l is slidably joined to the inner surface of a compression cylinder 5 in an airtight manner. A rod '36 is fixed to the lower end face. A hole 1a through which a rod 4 passes is provided in the center of the compression piston 1, which is connected to a drive part (not shown), and a rod seal 3 is installed in a groove on the inner peripheral surface of the hole 1a. be. The rod seal 3 and the rod 4 are slidably joined while maintaining airtightness. One end of the rod 4 is connected to a drive unit (not shown), and the other end of the rod 4 is fixed to a multistage expansion piston 6 having a four-stage convex shape.
Each stage of the multi-stage expansion piston 6 includes a piston ring 7,
．． 8, 9, and 10 are installed. The piston ring 7 is slidably joined to the cylinder surface 11a of the radiator 11 in an airtight manner. Lower flange tib of heat sink 11
is hermetically fixed to the - end of the compression cylinder 5, and the radiator 1
The upper flange 11C of No. 1 is airtightly fixed to the multi-stage expansion cylinder 12 having a five-stage convex shape.

The other end of the compression cylinder 5 is hermetically fixed to a housing of a drive device (not shown). A first regenerator cylinder 12a in the first stage of the multistage expansion cylinder 12 is provided with a first regenerator 13 having a hollow cylindrical shape. First regenerator 13
The inner diameter of the hollow portion is approximately equal to the inner diameter of the cylinder surface 11a of the radiator 11, and the inner diameter of the first stage 6 of the multistage expansion piston 6
This is to prevent the outer peripheral surfaces of a from coming into contact with each other. The first expansion cylinder 12b of the second stage of the multistage expansion cylinder 12
and a first stage 6a and a second stage 6b of the multistage expansion piston 6,
The space surrounded by the piston ring 7.8 then forms a first expansion space 14.

The space surrounded by the second expansion cylinder 12C of the third stage of the multistage expansion cylinder 12, the second stage 6b and third stage 5c of the multistage expansion piston 6, and the piston rings 8 and 9 is a space surrounded by the second expansion cylinder 12C of the third stage of the multistage expansion cylinder 12, and the space surrounded by the piston rings 8 and 9. A space 15 is formed.

The third expansion cylinder 12d of the fourth stage of the multistage expansion cylinder 12, the third stage 6C and the fourth stage of the multistage expansion piston 6
The space surrounded by the stage 6d and the piston ring 9.10 forms a third expansion space 16.

A space surrounded by the fourth expansion cylinder 128 of the fifth stage of the multistage expansion cylinder 12, the fourth stage 6d of the multistage expansion piston 6, and the piston ring 0 forms a fourth expansion space 18.

The second stage 6b, third stage 6c and fourth stage 6d of the multi-stage expansion piston 6 are each provided with a large number of holes 1B,
19.20 are provided, and one end of the holes 18, 19.20 are respectively connected to a second expansion space 15.20. 3rd expansion empty book 16. Fourth
It communicates with the expansion space 17. Holes 18, 19. The other end of '20 is the second stage 6b of the multistage expansion piston 6.
, the third stage Gc, and the ff12 provided inside the fourth stage 6d.
Cool storage device 21.・Third regenerator 22. It communicates with the fourth regenerator 23. The '- end (high temperature side) of the second N cooler 22 communicates with a large number of holes 24 provided at the bottom of the ff5 second stage 6b of the multi-stage expansion piston 6, and the holes 24 are connected to the first expansion space 14.
It is connected to. The other end (low-temperature side) of the second regenerator 21 communicates with part 1 (high-temperature side) of the third regenerator 22.
The other end (low temperature side) of the regenerator 22 is in communication with a fourth regenerator (high temperature side).

First expansion space 13, one end of first regenerator 13 (low temperature side)
The other end (high temperature side) of the first regenerator 13 is connected to the
It communicates with the pipe d of the radiator 11. The pipe lid includes a compression cylinder 5, a compression piston 1. Multistage expansion piston 6, radiator 11. Rod 4. It communicates with a compression space 25 surrounded by piston rings 2, 7 and rod seal 3. In this way, the main refrigerator is constructed.

A pre-cooled refrigerator RB is airtightly fixed to a hole around the upper flange of the radiator 11, and a cold head 51 that generates low-temperature refrigeration of the pre-cooled refrigerator B is
It is fixed to the outer surface of the first expansion cylinder 12b to the main refrigerator and the outer surface of the low temperature case of the first regenerator cylinder t2a. A first radiation shield plate 31 that internally accommodates the second radiation shield plate 26 and the second expansion cylinder 12c is fixed to the upper surface of the cold head 5J by a port 52. The upper flange 11C of the radiator ■1 is provided with a first radiation shield plate 31 for the main refrigerator and a first regenerator cylinder 1.
2a, and a vacuum tube 37 is fixed by a large number of holes 38 so as to house the cold head 51 of the precooling refrigerator B.

! An O-link groove is provided in the lower flange of the air pipe 37, and an O-ring 39 is attached thereto to keep the vacuum space 41 airtight. A hole 37 is formed on the outer peripheral surface of the vacuum chamber 37.
A is provided, and one end of a vacuum valve 40 is hermetically fixed.

Compressed space 25. Pipe 11d of radiator 11.

Section 1.2. s, q cold type 13, 21, 22. ．． 23, hole 2
1.1B, 19.20, 1.2.3°4 expansion space,
14, 15, 16. 17 are filled with working gas such as helium, and schooling cycle cold 41! It forms the working space of the machine. The lot 36 is driven by a drive unit (not shown) so that the lot 36 is approximately 90 degrees behind the lot 4 in phase.

The working gas in the compression space 25 is compressed by the compression piston 1 and the multi-stage expansion screw 6, generates heat and rises in temperature, and when it flows into the pipe 7lld of the radiator 1, the cooling water passing outside the pipe lid is heated. etc., the temperature drops, flows into the first regenerator 13, is cooled by the elements of the first regenerator 13, the temperature further decreases, and the first expansion space 14
flows into. When a part of the working gas that has flowed into the first expansion space 14 flows into the second regenerator 21 through the holes 24, it is cooled by the elements of the second regenerator 21, and its temperature further decreases. It flows into the regenerator 22. Hole 1
The working gas that has flowed into the second expansion space 8 flows into the second expansion space 15 . The working gas that has flowed into the third regenerator 22 is
It is further cooled by the second element, the temperature decreases, and it flows into the hole 19 and the fourth regenerator 23. The working gas that has flowed into the hole 19 flows into the third expansion space 16 . 4th N
The working gas that has flowed into the cooler 23 is further cooled by the element of the fourth regenerator 23, and its temperature decreases.
It flows into the fourth expansion space 17 through. First expansion space 1
4. Second expansion space 15. The working gas flowing into the third expansion space 6 and the fourth expansion space 17 is transferred to the multi-stage expansion piston 6.
Due to the downward movement of , it expands and refrigeration occurs at a lower temperature in sequence within No. 1, 2, and 3 J4. Due to the northward movement of the multistage expansion piston 6, the working gas in the fourth expansion space 17 flows into the fourth regenerator 23 through the holes 20, is warmed by the elements of the fourth regenerator 23, and its temperature increases. , flows into the third regenerator 22. The working gas in the third expansion space 16 flows into the third regenerator 22 through the holes 19 . The working gas that has flowed into the third regenerator 22 is warmed by the elements of the third regenerator 22, its temperature rises, and then flows into the second regenerator 21. The working gas in the second expansion space 15 flows into the second regenerator 21 through the holes 18 . The working gas that has flowed into the ff12 regenerator 21 is warmed by the elements of the second regenerator 21, its temperature rises, and then flows into the first expansion space 14 through the holes 24. The working gas in the first expansion space 14 flows into the first regenerator, is warmed by the elements of the first regenerator 13, its temperature rises by 2, and flows into the compression space 25 through the pipe 11d of the radiator 11. do. In this way, one batch of Sfling cycle refrigerator is completed.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional cryogenic refrigerator, FIG. 2 is a conventional sectional elevational view of a conventional reversible refrigerator, and FIG. 3 is a central vertical sectional view showing an embodiment of the present invention. . Heat sink...11. 1st expansion space...14° 1st M cold type...13° 1st Wi refrigerant cylinder...12a. First expansion cylinder...12b. Second expansion cylinder...12c. 2nd radiation shield plate...26° 1st radiation shield slope...31° Patent applicant 1 Ishishi Kozueki Company Representative Reio Nakai 2nd 1st 11th

Claims (1)

[Claims] A first regenerator 13 is provided between the radiator 11 and the first expansion space 14.
A first regenerator cylinder 12a that accommodates the first regenerator cylinder 12a, a first expansion cylinder 12b forming the first expansion space 14, and a second expansion space 12a is provided.
15 of the second expansion cylinder 12c near the ff1l expansion cylinder 12b, and a second radiation shield plate 26 fixed to the second expansion cylinder 12c and the second expansion cylinder 12c. A Stirling cycle cryogenic refrigerator in which one or more radiation shield plates 31 are cooled with a refrigerant other than the working gas forming the refrigeration cycle of the unrefrigerated machine.