JPH04278146A - Freezer device - Google Patents

Abstract

PURPOSE:To provide a small-sized and light weight freezer device which is convenient in use and produces a high freezing amount and in which evaporated herium gas is condensed at a temperature lower than 5.0K or a cooled item is cooled to a temperature lower than 5.0K. CONSTITUTION:An expansion device 1 is used in a cryogenic generating device and then the cryogenic state can be accomplished by controlling the pressure at an outlet of a J.T valve 13 disposed at a lower end of each of heat exchangers 6, 7, 9, 10 and 12 of the J.T circuit from a positive level to an arbitrary negative pressure with the same compressor device 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigeration system, and more particularly to a refrigeration system that lowers the cooling temperature to a desired temperature and increases the amount of refrigeration.

0002

[Prior technology] Nuclear magnetic resonance diagnostic equipment using superconducting magnets, thermophysical property measuring equipment, various electronic devices such as Josephson elements and various sensors, cryopumps with high vacuum and high pumping speed, and superconducting magnets are used. Cryogenic liquid helium is used as a refrigerant for electron accelerators and synchrotron radiation generators. If the refrigerant temperature of these cooled devices is kept below the evaporation temperature of liquid helium in the atmosphere, especially 4.2 K, it will be possible to stabilize superconducting magnets, increase the magnetic field, and improve the N of various sensors.
This is very effective in improving the S ratio.

Liquid helium, a refrigerant, evaporates with a small amount of heat and is expensive, so a refrigeration device is installed to condense the evaporated helium gas. In addition, in thermophysical property measuring equipment,
It is necessary to cool the object to be cooled over a wide range of cooling temperatures of 4.2K or less.

The structure of this refrigeration system is that helium gas pressurized by a compressor unit in which two scroll compressors with different compression ratios are arranged in two stages is used as a cold generator for pre-cooling by Gifford McMahon (G. The Joule-Thomson circuit (J.T.
The exhaust helium gas from the cold generator for precooling is returned to the medium pressure line of the compressor unit arranged in the two stages, and the exhaust helium gas from the J/T circuit is supplied to the high pressure flow path of the J/T circuit through the same piping. A method of returning the pressure to the low pressure line of the compressor unit arranged in the two stages is described in Refrigeration, Vol. 36, No. 733 (Showa 6).
(November 3rd year), pages 81 to 87.

In this case, the exhaust helium gas from the J/T valve of the J/T circuit is recovered at a positive pressure of 1.0 atm or more at the intake port of the compressor. Therefore, the J/T valve outlet pressure of the J/T circuit increases by the pressure loss in the low pressure passage in the circuit, and becomes approximately 1.2 atm or more. Therefore, the freezing temperature of this refrigeration device is 4.5K or higher. In addition, the helium gas pressurized by the compressor unit is connected to the cold generation circuit,
Since the high pressure flow path of the T circuit is supplied through the same piping, fluctuations in the flow rate and pressure of the cold generation circuit caused by changes in heat load, etc. will affect the high pressure and low pressure flow paths of the J/T circuit, resulting in a stable cooling temperature. and stable frozen amount cannot be obtained.

[0006] In addition, a compressor unit in which two scroll compressors with different compression ratios are arranged in two stages is used to supply pressurized helium gas to the high-pressure flow path of the cold generator circuit and the J/T circuit. The two scroll compressors are separately and finely controlled in order to simultaneously supply them through the same piping and return the exhaust gas from the cold generator circuit and J/T circuit to the medium pressure and low pressure lines of the compressor unit, respectively. There is a need to make refrigeration equipment smaller and lighter and easier to operate.

[0007] Further, the structure of another refrigeration system is described in Japanese Patent Application Laid-Open No. 61-235648. This refrigeration system uses a Solvay type or Gifford-McMahon (G.M.) type reciprocating expander as a cold generator for pre-cooling.
Liquid helium temperature is generated in a J/T circuit that is equipped with stages of compressors (generally rotary type or reciprocating type) and has a J/T valve in the cryogenic section. Helium gas compressed by a compressor in a separate route is supplied to the expander and J/T circuit, and helium gas is supplied to the expander and J/T circuit.
Exhausted helium gas from the T circuit is recovered at a positive pressure of 1.0 atm or more at the inlet of the compressor. Therefore, the J/T valve outlet pressure of the J/T circuit increases by the pressure loss in the circuit, and becomes approximately 1.2 atm or more. In this case as well, the freezing temperature is 4.5K or higher.

[0008] Also, in this case, since a compressor unit is used in which two compressors with different compression ratios are arranged in two stages, it is necessary to finely control the compressors separately. The focus is on ease of use and ease of operation. In this case, since the compressor unit is configured using two rotary compressors and two oil removal and recovery circuits in the same flow path, the refrigeration system can be made smaller and lighter.

Another refrigeration device structure is a Claude cycle refrigerator (a cold generation circuit that uses a reciprocating expander as a cold generator for precooling helium gas pressurized by a compressor unit, and a J. A method in which low-pressure helium gas is supplied to the high-pressure passages of the J and T circuits, which have a T-valve in the cryogenic part, through the same piping, and is sucked into the compressor unit through the piping where the low-pressure passages of both circuits join together. A compressor unit in which two identical scroll compressors are arranged in one stage in parallel was published in Proceedings of the Japan Society of Cryogenic Engineering and Superconductivity, 44th, (November 1990) No. 9.
It is described on page 6.

[0010] Also in this refrigeration system, J of the J・T circuit
・Recover the exhaust helium gas from the T-valve at the inlet of the compressor at a positive pressure of 1.0 atm or more. Therefore, J
・The T valve outlet pressure is J where the low pressure flow path of the cold generation circuit merges.
・The pressure loss in the low pressure flow path of the T circuit increases by approximately 1.2at.
m or more. Therefore, the freezing temperature of this freezing device is 4
．． 5K or more.

[0011] Furthermore, since the helium gas pressurized by the compressor unit is supplied to the high-pressure flow path of the cold generation circuit and the J/T circuit through the same piping, the flow rate and pressure of the cold generation circuit caused by fluctuations in heat load, etc. This fluctuation affects the high-pressure and low-pressure channels of the J/T circuit, making it impossible to obtain a stable cooling temperature and a stable amount of refrigeration. In this case as well, the compressor unit is constructed using two scroll compressors and two systems of oil removal and recovery circuits in the same flow path, making the refrigeration system smaller and lighter, and the cold generation circuit and The reason for this is the simplicity of the helium gas flow distribution operation to the T circuit.

0012

[Problems to be Solved by the Invention] However, as described above, the conventional techniques do not mention a method of cooling while stably controlling the temperature to an arbitrary temperature below 4.5K. Further, when the compressor suction port is made to have a negative pressure, there is a problem that the discharge pressure decreases, the amount of refrigeration in the precooling refrigeration generation circuit decreases, and the cooling temperature rises to 4.5K or more. Further, there is no mention of ease of operation of the compressor and methods for reducing the size and weight of the compressor.

[0013] The object of the present invention is to provide a compact and lightweight device that condenses evaporated helium gas at a temperature below 4.5K or stably cools an object to be cooled below 4.5K, particularly below the temperature of liquid helium at atmospheric pressure of 4.2K. It is an object of the present invention to provide a refrigeration device that is easy to operate and that stably generates a large amount of refrigeration.

[0014]

[Means for Solving the Problems] The above object is to pump helium gas in the low pressure flow path of the J/T circuit to a range from positive pressure to negative pressure at the intake port of the compressor without using auxiliary exhaust means such as a vacuum pump. The helium gas collected by J and pressurized to positive pressure by the same compressor is
・Achieved by supplying the same compressor to the high pressure flow path of the T circuit.

That is, the present invention includes a heat exchanger incorporating a series of high-pressure piping and low-pressure piping isolated from a cold generation circuit for pre-cooling, and an expansion valve provided in the cryogenic part of the high-pressure piping. An outlet of the expansion valve is guided into a refrigerant container containing a cooled object, a low temperature part of the low pressure pipe communicates with the outlet of the expansion valve in the refrigerant container, and the high pressure pipe and the low pressure pipe are in a normal temperature part. The compression means of the refrigeration apparatus communicated through the compression means is characterized in that the compression means has multiple small compression chambers that are isolated and continuous within the compression chambers within the compression means.

Further, the present invention includes a heat exchanger incorporating high-pressure piping and low-pressure piping, and an expansion valve provided in the cryogenic part of the high-pressure piping, the outlet of the expansion valve is set to negative pressure, and the outlet is guided into a refrigerant container containing an object to be cooled, a low-temperature section of the low-pressure pipe communicates with an outlet of the expansion valve within the refrigerant container, and the high-pressure pipe and the low-pressure pipe are connected to each other through a compression means at a normal temperature section. The compression means of the refrigeration apparatus communicated with each other is characterized in that the compression means has multiple small compression chambers separated and continuous within the compression chambers within the compression means.

Furthermore, the present invention includes a heat exchanger incorporating a series of high-pressure piping and low-pressure piping isolated from a cold generating circuit for pre-cooling, and an expansion valve provided in the cryogenic part of the high-pressure piping. The outlet of the expansion valve is set to negative pressure and is guided into a refrigerant container containing a cooled object, and the low-temperature part of the low-pressure pipe communicates with the outlet of the expansion valve in the refrigerant container, and the high-pressure pipe and the low-pressure The compression means of the refrigeration system, in which the pipes communicate with each other through the compression means at a normal temperature section, has multiple stages in the compression chamber within the compression means.
The compressor is characterized in that each compressor has separate and continuous small compression chambers.

Further, the present invention includes a heat exchanger incorporating a series of high-pressure piping and low-pressure piping isolated from a cold generation circuit for pre-cooling, and an expansion valve provided in the cryogenic part of the high-pressure piping. An outlet of the expansion valve is guided into a refrigerant container containing a cooled object, a low temperature part of the low pressure pipe communicates with the outlet of the expansion valve in the refrigerant container, and the high pressure pipe and the low pressure pipe are in a normal temperature part. It is characterized by adjusting the pressure at the suction port of the compression means, which communicates through the compression means and has multiple small compression chambers isolated and continuous within the compression chamber, in a range from positive pressure to negative pressure.

[0019] In each of the above inventions, (1) the compression means has a plurality of compression means arranged in series, each having a multi-stage, isolated and continuous small compression chamber within the compression chamber within the compression means; (2) The compression means is a scroll-type compressor or screw-type compressor having multiple small compression chambers that are isolated and continuous within the compression chambers within the compression means; (3) The compression means is a (4) The compression means is an oil-lubricated compression means having multiple small compression chambers each separated and continuous within a compression chamber within the compression means; be a single compression means with isolated and continuous small compression chambers;
(5) The compression means is a one-stage, plurality of compression means each having a plurality of isolated and continuous small compression chambers in the compression chambers within the compression means; (6) the compression means is a compression means; (7) at least the processing air volume of the compression means, or (8) controlling the temperature or pressure in the refrigerant container by adjusting the air flow rate passing through the expansion valve and the bypass air flow between the high and low pressure flow paths; In the refrigeration equipment communicated through the refrigeration system, an isolating means is provided to prevent the connecting portion of the low-pressure pipe in the normal temperature section from coming into contact with the atmosphere; (9) the low-pressure pipe in the normal temperature section is arranged within the high-pressure pipe; 10) An expansion valve is provided in the cryogenic part of the high-pressure pipe, and the outlet of the expansion valve is guided to a heat transfer body that holds the object to be cooled, and the low-pressure pipe and the outlet of the expansion valve communicate with each other, and the high-pressure pipe and the outlet of the expansion valve communicate with each other. The compression means of the refrigeration system with which the low-pressure piping communicates through the compression means at room temperature is a compression means having multiple small compression chambers that are isolated and continuous within the compression chambers within the compression means. The following aspects are effective.

[0020]

[Operation] For example, a Gifford-McMahon (G.M.) type reciprocating expander is used as the cold generator for precooling, and the pressure at the J/T valve outlet of the J/T circuit isolated from the cold generation circuit for precooling is used. is stably controlled to any value from positive pressure to negative pressure. As a result, any helium temperature below 4.5 K can be stably generated at the J/T valve outlet.

Furthermore, by increasing the helium gas flow rate of the J/T circuit, the amount of refrigeration below 4.5K can be easily and stably increased. In addition, the helium gas collected at the inlet inlet in a range of positive pressure to negative pressure and compressed to positive pressure is
・By performing the operation of supplying to the high-pressure flow path of the T circuit using the same compressor, the refrigeration system becomes small, lightweight, and simple.

[0022]

[Embodiment] An embodiment of the present invention will be explained below with reference to FIG. The cold generator 1 placed in the cold generating circuit for pre-cooling is
For example, it consists of a Gifford-McMahon expander.

The high-pressure helium gas in the helium compressor unit 2 flows into the cold generator 1 and is adiabatically expanded inside, and the temperature reaches approximately 40K in the first stage 3 and second stage 4, respectively.
, generates a cold of 15K. The expanded gas returns to the compressor unit 2 again.

On the other hand, the J
- High-pressure helium gas pressurized by the compressor unit 5 of the T circuit passes through the high-pressure pipe 16a to the first heat exchanger 6 and the second heat exchanger 6.
It passes through the heat exchanger 7, the first adsorber 8, the third heat exchanger 9, the fourth heat exchanger 10, the second adsorber 11, and the fifth heat exchanger 12, and is cooled to a temperature of about 6K or less, and the J.T. A portion of the gas is adiabatically expanded by the valve and liquefied, and is collected in the liquid helium tank 14 to cool objects to be cooled such as the superconducting magnet 15.

Unliquefied helium gas, liquid helium 14
The evaporated gas of a flows into the low pressure pipe 16b and is transferred to the fifth heat exchanger 12, the third adsorption device 17, the third heat exchanger 9, and the fourth adsorption device 1.
8, passes through the first heat exchanger 6 and the fifth adsorber 18a, reaches approximately room temperature, and returns to the compressor unit 5 via the low pressure pipe 16b. The inside of the cryostat 19 is vacuum insulated, and the cryogenic part is heat shielded by a liquid nitrogen tank 21, a bottom plate 22, and a top plate 23.

Evaporated gas of the liquid nitrogen 20 is discharged to the atmosphere through an exhaust pipe 24, and the liquid nitrogen is periodically replenished in a liquid nitrogen tank 25. Each adsorber removes impurities from helium gas.

The structure of the compressor unit 5 is shown in FIGS. 2 and 3, which are sectional views of the compression chamber of the scroll compressor 26. The compressor unit 5 includes a scroll compressor 26, an oil/gas mixed high-pressure fluid cooler 27, an oil separator 28, an oil absorber 29, and an oil cooler 30. The low-pressure helium gas in the low-pressure pipe 16b flows into the scroll-type compression chamber 31 in the scroll-type compressor 26 from the low-pressure inlet 32, and the fixed scroll 3
Small compression chambers 31a, 31b, 31c, 31d, 31 are formed while moving between 1a and the orbiting scroll 31y.
Pressure is gradually increased with e.

Since helium gas becomes high in temperature due to the heat of compression, a portion of the high temperature lubricating oil stored at the bottom of the scroll compressor 26 is guided through the pipe 33 to the oil cooler 30.
It is supplied to the intermediate pressure compression chamber 31b of the scroll type compression chamber 31 from the pipe 34 through the intermediate pressure inlet 35 at approximately room temperature. As a result, the temperature of the helium gas is cooled to about 350 K, and the helium gas is further compressed and discharged from the high-pressure outlet 36 of the scroll-type compression chamber 31 into the scroll-type compressor 26 .

In this way, inside the scroll type compression chamber 31, while moving toward the center of the scroll, and
Small compression chambers 31a, 31b, 31c formed in isolation
, 31d, and 31e, the helium gas is gradually pressurized, so there is almost no gas leakage between the small compression chambers.

Therefore, the helium gas flowing into the small compression chamber 31a can be pressurized at a pressure of 1.0 atm or less, compressed to a high pressure, and then discharged.

On the other hand, most of the lubricating oil supplied into the medium pressure compression chamber 31b and coming out from the high pressure outlet 36 returns to the bottom of the scroll compressor 26, and the remaining lubricating oil is entrained in the high pressure helium gas. , oil and gas flow into the high pressure fluid cooler 27 . Here, the mixed fluid is cooled and about 99% of the fluid is cooled.
99% of the oil is separated and most of it is re-supplied into the intermediate pressure chamber of the scroll type compression chamber 31 via the oil return piping 37 and the piping 34. The remaining high-pressure helium gas containing 0.01% oil passes through an oil absorber 29 filled with activated carbon, for example, and is purified to an oil concentration of approximately 0.01 ppm.
is supplied to the first heat exchanger 6.

The temperature at the outlet of the J·T valve 13 is determined by the pressure of the helium gas after being expanded by the J·T valve, that is, the liquefaction saturation pressure in the helium tank. On the other hand, the pressure inside the helium tank is determined by (1) the flow rate of helium gas passing through the J/T valve, (2) the low pressure piping, the low pressure channels in the first, second, and third heat exchangers, the third adsorption device, and the fourth adsorption device. The pressure loss is determined by (3) the suction air volume of the scroll compressor (4) the air volume of the bypass gas that passes through the pressure regulating valve 16c provided between the high and low pressure pipes.

Therefore, by appropriately controlling the above four conditions, the pressure in the helium tank can be adjusted to an arbitrary value, that is,
The helium temperature after the J/T valve can be set to any value. In addition, the J/T circuit, especially the low-pressure piping, is isolated from the cold generation circuit for precooling, so pressure fluctuations in the cold generation circuit are
It does not affect the pressure at the valve outlet. Therefore, J.
The pressure at the T-valve outlet can be stably maintained even at 1.2 atm or less, and a cooling temperature of less than 4.5 can be stably maintained.

Furthermore, since the cold generated by the J/T valve is generated by isenthalpic expansion, a large amount of refrigeration of 4.5K or less can be obtained. Therefore, the compressor input electric power per unit amount of refrigeration can also be reduced.

The pressure in the helium tank is measured by a pressure sensor 38, and the temperature is measured by a temperature sensor 39 and a temperature sensor 40, and the data is sent to a controller 41 in the compressor unit 5 to maintain a predetermined pressure and temperature. Then, the rotational speed of the electric motor 42 of the scroll compressor 26 and the opening degree of the J/T valve 13 are adjusted.

With this control, the pressure at the outlet of the J/T valve is reduced to 1.
It can be adjusted in a range of 2 atm or less, and thereby the cooling temperature can be stably controlled in a range of less than 4.5K. This is J
・A T-circuit helium compressor has multiple stages inside the compression chamber, and
By applying a scroll compressor, each of which has a series of isolated small compression chambers, and a compression ratio of 10 or more, this has become possible with a single compressor in the J/T circuit.

By cooling the superconducting magnet 15 to less than 4.5K, especially 4.2K or less, the amount of heat stored in the superconducting magnet increases, suppressing the occurrence of quenching due to local heat generation, etc., improving the stability of the superconducting magnet. The strength of the generated magnetic field can be increased by increasing the applied current.

[0038] Furthermore, the amount of refrigeration at the above cooling temperature is (
1) Use a material with high low-temperature heat storage properties as the cold storage material of the cold generator. (2) Adjust the operating frequency of the cold generator. (3) J.T.
Increasing the flow rate of helium gas passing through the valve (4) This can be easily increased by increasing the operating frequency of the scroll compressor to increase the suction/discharge air volume.

As described above, according to this embodiment, the helium gas in the low pressure flow path of the J/T circuit isolated from the cold generation circuit for precooling is recovered at the inlet of the compressor in a range of positive pressure to negative pressure. ,
Since helium gas pressurized to a high positive pressure by the same compressor can be supplied to the high pressure flow path of the JT circuit, the pressure at the J·T valve outlet can be controlled to any value from positive pressure to negative pressure. As a result, J.
This has the effect that any helium temperature below 4.5K can be stably generated at the T-valve outlet.

Furthermore, according to this embodiment, the helium gas in the low-pressure flow path of the J/T circuit, which is isolated from the cold generation circuit for pre-cooling, is recovered at the inlet of the compressor in a range of positive pressure to negative pressure. However, the operating pressure conditions of the cold generating circuit for pre-cooling do not change and a predetermined amount of cold can be stably supplied. Therefore, since the precooling section of the J/T circuit can be cooled stably, an arbitrary helium temperature of less than 4.5 K can always be stably generated at the J/T valve outlet.

Furthermore, by increasing the helium gas flow rate of the J/T circuit, the amount of refrigeration of less than 4.5 K generated by isenthalpic expansion by the J/T valve can be easily increased, and This has the effect of requiring less input power to the compressor per unit amount of refrigeration.

Furthermore, by performing the operation of supplying helium gas to the high-pressure flow path of the J/T circuit using the same compressor, the refrigeration system can be made small, lightweight, and simple.

[0043] In this embodiment, the cold generator is equipped with G.M.
Although the explanation was given using an example where a cooling temperature is less than 4.5K using a cycle expander, the same effect can be achieved with a refrigeration cycle or a Brayton cycle that uses a Solvay cycle, Stirling cycle, Billmeyer cycle, turbine type, or Claude type expander. However, even if the cooling temperature is 4.5K or higher, the same effect can be applied in terms of improving temperature stability. Further, in this embodiment, an example in which a scroll type compressor is applied to the compressor has been described, but the same effect can be obtained even if a screw compressor is applied.

In this example, the case where a superconducting magnet is used as the object to be cooled has been explained, but it is also applicable to various electronic devices such as a thermophysical property measuring device, a Josephson element, various sensors, and a high-vacuum, high-pumping-speed cryostat. Even if the panel is used as the object to be cooled, the temperature of the object to be cooled decreases, thereby increasing the SN ratio and increasing the pumping speed.

Another embodiment of the invention is shown in FIG. This figure shows the configuration of a compressor unit using a scroll compressor in which two compression chambers 31 are arranged in parallel in the same pressure vessel.

According to this embodiment, since the suction/discharge air volume can be increased by using the multiple single-stage scroll compressor, a larger amount of the exhaust helium gas in the low pressure flow path of the J/T circuit can be transferred to the intake port of the compressor. The helium gas recovered from positive pressure to negative pressure by the same compressor can be supplied to the high pressure flow path of the JT circuit, so the pressure at the J・T valve outlet can be changed from positive pressure to negative pressure. The range that can be controlled to any value is expanded, and this allows J.
This has the advantage that any helium temperature within a wide range of 4.5 K or less can be generated at the T-valve outlet.

[0047] Also, the helium gas flow rate of the J/T circuit is set to 2.
Since it can be doubled, the amount of refrigeration below 4.5K can be easily increased. In addition, the oil separation system can be combined into one, which reduces weight, and the lubricating oil extraction and injection system for gas cooling can be combined into one, which reduces weight and allows simultaneous cooling of two compressors. The operation of injecting oil becomes easier. This is because the oil levels in the two compressors are always constant.

Furthermore, it is collected under negative pressure at the inlet of the suction port,
By performing the operation of supplying helium gas compressed to positive pressure to the high-pressure flow path of the J/T circuit in the same compressor, the refrigeration system can be made small, lightweight, and simple.

Another embodiment of the invention is shown in FIG. This figure shows a configuration in which the J/T valve outlet and the low pressure pipe are communicated via a condenser 38 in the J/T circuit. According to this embodiment, the J/T circuit and the inside of the liquid helium tank can be isolated, so even if the pressure inside the liquid helium tank fluctuates due to changes in the heat load inside the liquid helium tank, the flow rate of the J/T circuit and The pressure in the low-pressure pipe does not fluctuate, and therefore the cooling temperature of the condenser 38 is stabilized.

Another embodiment of the invention is shown in FIG. This figure shows how the low pressure pipe 16b passing through the fifth adsorber 18a and the suction port pipe 16c of the compressor unit 5 are connected to the joint 3 in the J/T circuit.
9 is connected to the low pressure pipe 16d. A container 40 of an atmosphere isolation jig is provided around the joint 39 to isolate it from the atmosphere and communicate the container 40 with the high pressure pipe 16a through a pipe 16e.

According to this embodiment, it is possible to prevent air that becomes an impurity from flowing into the J/T circuit from the joint 39 in the low pressure piping under negative pressure, and to prevent troubles in the refrigeration system due to blockage of the J/T valve, etc. effective

[0052]

According to the present invention, the pressure at the outlet of the J/T valve, which is isolated from the cold generation circuit for precooling, can be controlled to any value from positive pressure to negative pressure. An arbitrary helium temperature of .5K or less can be generated, and the cooling temperature of the object to be cooled can be cooled to an arbitrary temperature of 4.5K or less.

Furthermore, by increasing the flow rate of helium gas in the J/T circuit, the amount of refrigeration below 4.5K can be easily increased. In addition, by using the same compressor to supply helium gas, which is collected under negative pressure at the inlet and compressed to positive pressure, to the high-pressure flow path of the J/T circuit, this device is small, lightweight, and simple. There is an effect that can be achieved by refrigeration equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the configuration of a refrigeration system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the configuration of a compressor unit for a J/T circuit used in an embodiment of the present invention.

FIG. 3 is a diagram illustrating a cross section of a compression chamber of a compressor unit for a J/T circuit used in an embodiment of the present invention.

FIG. 4 is a diagram illustrating the configuration of a compressor unit for a J/T circuit used in another embodiment of the present invention.

FIG. 5 is an explanatory diagram of the configuration around the J/T valve of a refrigeration system according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration in which an atmospheric isolation jig is provided at a joint of a low-pressure pipe of a compressor unit according to another embodiment of the present invention.

[Explanation of symbols]

1... Expander, 5... Compressor unit, 6, 7, 9, 10,
12...Heat exchanger, 13...J/T valve, 14a...Liquid helium, 15...Superconducting magnet.

Claims (16)

[Claims] 1. A heat exchanger incorporating a series of high-pressure piping and low-pressure piping isolated from a cold generation circuit for pre-cooling, and an expansion valve provided in a cryogenic part of the high-pressure piping, the expansion valve comprising: An outlet of the low pressure pipe is guided into a refrigerant container containing a cooled object, a low temperature part of the low pressure pipe communicates with an outlet of the expansion valve within the refrigerant container, and the high pressure pipe and the low pressure pipe are connected to a compression means in a normal temperature part. A refrigeration system characterized in that the compression means of the refrigeration system communicated with each other through the compression means is a compression means having multiple small compression chambers that are isolated and continuous within the compression chambers within the compression means. 2. A heat exchanger having built-in high-pressure piping and low-pressure piping, and an expansion valve provided in the cryogenic part of the high-pressure piping, wherein the outlet of the expansion valve is set to negative pressure, and the outlet is cooled. The low-temperature part of the low-pressure pipe communicates with the outlet of the expansion valve within the refrigerant container, and the high-pressure pipe and the low-pressure pipe communicate with each other through a compression means at a normal temperature part. The compression means of the refrigeration device has multiple stages within the compression chamber within the compression means,
A refrigeration system characterized in that the compression means each has isolated and continuous small compression chambers. 3. A heat exchanger incorporating a series of high-pressure piping and low-pressure piping isolated from a cold generation circuit for pre-cooling, and an expansion valve provided in a cryogenic part of the high-pressure piping, the expansion valve comprising: The outlet of the low-pressure pipe is set to negative pressure and is guided into a refrigerant container containing a cooled object, the low-temperature part of the low-pressure pipe communicates with the outlet of the expansion valve within the refrigerant container, and the high-pressure pipe and the low-pressure pipe are connected to each other. A refrigeration system, wherein the compression means of the refrigeration system communicates with each other through a compression means in a normal temperature part, and the compression means has multiple small compression chambers that are isolated and continuous within a compression chamber within the compression means. 4. A heat exchanger incorporating a series of high-pressure piping and low-pressure piping isolated from a cold generation circuit for pre-cooling, and an expansion valve provided in a cryogenic part of the high-pressure piping, the expansion valve comprising: An outlet of the low pressure pipe is guided into a refrigerant container containing a cooled object, a low temperature part of the low pressure pipe communicates with an outlet of the expansion valve within the refrigerant container, and the high pressure pipe and the low pressure pipe are connected to a compression means in a normal temperature part. A refrigeration system that adjusts the pressure at the suction port of a compression means in a range from positive pressure to negative pressure. [Claim 5] Helium gas in the low-pressure flow path of the J/T circuit is recovered at the inlet of the compressor in a range of positive pressure to negative pressure without using auxiliary exhaust means, and the compressor increases the pressure to positive pressure. A refrigeration system characterized by supplying pressurized helium gas to the high-pressure flow path of the J/T circuit using the same compressor. 6. The compression means is characterized in that a plurality of compression means are arranged in series, the compression means each having a continuous small compression chamber separated from each other in multiple stages within the compression chamber within the compression means. The refrigeration device described in any of the above. 7. Claims 1 to 5, wherein the compression means is a scroll compressor having multiple small compression chambers each separated and continuous within the compression chamber within the compression means.
The refrigeration device described in any of the above. 8. Claims 1 to 5, wherein the compression means is a screw type compressor having multiple small compression chambers separated from each other and continuous within the compression chambers within the compression means.
The refrigeration device described in any of the above. 9. The compression means has a plurality of continuous small compression chambers that are separated from each other in a compression chamber within the compression means.
The refrigeration system according to any one of claims 1 to 5, characterized in that it is an oil-lubricated compression means. 10. Claims 1 to 5, characterized in that the compression means is a single compression means having multiple small compression chambers each isolated and continuous within the compression chamber within the compression means.
The refrigeration device described in any of the above. 11. The compression means is a compression means having a plurality of units in one stage, each having a plurality of small compression chambers separated from each other and continuous in a compression chamber within the compression means. 5. The refrigeration device according to any one of 5. 12. The compression means is a compression means in which a plurality of small compression chambers are housed in one pressure vessel, each having a plurality of separate and continuous small compression chambers within the compression chamber thereof. The refrigeration apparatus according to any one of claims 1 to 5. 13. A claim characterized in that the temperature or pressure within the refrigerant container is controlled by adjusting at least the amount of air processed by the compression means, the amount of air passing through the expansion valve, and the amount of bypass air between high and low pressure channels. Item 5. Refrigeration device according to any one of Items 1 to 5. 14. A refrigeration system in which the high-pressure pipe and the low-pressure pipe communicate with each other through a compression means in a room temperature section, further comprising isolation means to prevent the connecting portion of the low-pressure pipe in the room temperature section from coming into contact with the atmosphere. The refrigeration apparatus according to any one of claims 1 to 5. 15. The refrigeration system according to claim 1, wherein the low-pressure pipe of the room temperature section is disposed within the high-pressure pipe. 16. An expansion valve is provided in a cryogenic part of the high-pressure pipe, an outlet of the expansion valve is guided to a heat transfer body that holds an object to be cooled, and an outlet of the low-pressure pipe and the expansion valve communicate with each other, The compression means of the refrigeration system in which the high pressure piping and the low pressure piping communicate with each other via the compression means at a normal temperature part has multiple small compression chambers that are isolated and continuous within the compression chambers within the compression means.
The refrigeration system according to any one of claims 1 to 5, characterized in that it is a compression means.