JPH0349022B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a Joel-Thomson refrigeration system, which is used, for example, in a superconducting magnet.

(Prior Art) As a conventional closed cycle cooling device of this type, there has been one shown in FIG. That is, in FIG. 3, 1 is a pre-cooling refrigerator, 2, 3 and 4 are pre-cooling heat exchangers that are in contact with this pre-cooling refrigerator 1 in a heat exchange manner,
5, 6, 7, and 8 are countercurrent heat exchangers, and in these high-pressure side flow paths, the precooling heat exchanger and 5, 2,
They are connected in the order of 6, 3, 7, 4, and 8. 9 is a compressor connected to this high-pressure side flow path, 10 is a Joel-Thomson (hereinafter referred to as J-T) valve connected to the high-pressure side flow path of the heat exchanger 8, and 11 is connected to the J-T valve 10. A liquid refrigerant container having a piping opening (load absorption heat exchanger) 13 is an object to be cooled in the liquid refrigerant container 11, and 12 is a buffer tank located between the low pressure side flow path of the heat exchanger 5 and the compressor 9. 14 is a vacuum container. The refrigerant gas sent out from the compressor 9 is sequentially cooled by the heat exchangers 5, 6, 7, 8 and the pre-cooling heat exchangers 2, 3, 4 which are cooled by the pre-cooling refrigerator 1, and is subjected to J-T expansion. The refrigerant cools down and some of the refrigerant liquefies. The liquefied refrigerant is stored in the liquid refrigerant container 11, and the gas passes through the low-pressure side channels of the heat exchangers 8, 7, 6, and 5, and is heated by exchanging heat with the refrigerant gas passing through the high-pressure side channels. Enter 12 and compressor 9
Return to In this way, the refrigeration cycle is performed.

(Problems to be Solved by the Invention) However, in this conventional system, the liquid refrigerant container 11 that cools the object 13 to be cooled and the precooling refrigerator 1 that is the source of vibrations, magnetic fields, etc. are disposed in the vacuum container 14. Because they are combined together, there are disadvantages in that the object to be cooled 13 is adversely affected by vibrations, magnetic fields, etc., and it is difficult to disassemble and repair the pre-cooling refrigerator, etc. while the object to be cooled 13 is being cooled with liquid refrigerant. The drawback was that I couldn't do it.

Therefore, the present invention is designed to prevent the harmful effects of vibrations, magnetic fields, etc. from being exerted on the object to be cooled, and to make it possible to disassemble and repair a pre-cooling refrigerator, etc. while maintaining the state in which the object to be cooled is cooled. The technical challenge is to make it possible.

[Structure of the invention]

(Means for Solving the Problems) The measures taken to solve the above-mentioned technical problems include a pre-cooling refrigerator, a compressor that compresses refrigerant gas, and a flow of refrigerant gas discharged from the compressor into each other. a plurality of heat exchangers, each having a high-pressure side flow path communicated with the other and a low-pressure side flow path through which refrigerant gas sucked into the compressor is communicated with each other, and the refrigerant gas flowing through each flow path exchanges heat with each other; , a plurality of precooling heat exchangers that are respectively interposed between the high pressure side flow paths of the plurality of heat exchangers and precool the refrigerant gas by the precooling refrigerator;
a Joel-Thomson valve connected to the high-pressure side flow path of the heat exchanger located at the most downstream side of the high-pressure side flow paths of the plurality of heat exchangers to cause refrigerant gas to undergo Joel-Thomson expansion; In the Joel-Thomson refrigeration system comprising a valve and a load absorber interposed between a low-pressure flow path of the heat exchanger located most downstream, the heat exchanger located most downstream , the Joel-Thomson valve and the load absorber are housed in a load vacuum vessel, and the precooling refrigerator, the precooling heat exchanger, and the remaining plurality of heat exchangers are housed in a refrigerator vacuum vessel, and the A high-pressure inlet pipe having a plurality of inlets is connected to the high-pressure side flow path of the heat exchanger located on the most downstream side, and an inlet of the high-pressure inlet pipe is connected to the low-pressure side flow path of the heat exchanger located on the most downstream side. low-pressure outlet pipes having the same number of outlet sections as the load vacuum vessel are connected to form a plurality of pairs of inlet/outlet sections that airtightly penetrate the load vacuum container, and one pair of the high-pressure inlet piping and the low-pressure outlet tube of the plurality of pairs of inlet/outlet sections are connected. The inlet/outlet portion of the outlet piping is connected to the high-pressure side flow path of the heat exchanger located at the most downstream side of the high-pressure side flow paths of the remaining heat exchangers through flexible high-pressure piping and low-pressure piping, respectively. and flexible vacuum piping connected to the low pressure side flow path, accommodating the high pressure piping and the low pressure piping between the refrigerator vacuum container and the load vacuum container, and vacuum-sealing the refrigerator vacuum container. A high-pressure stop valve and a low-pressure stop valve are interposed near the entrances and exits of the plurality of pairs of high-pressure inlet piping and low-pressure outlet piping, respectively, and a respective A bypass valve is provided between the low pressure stop valve and the inlet of each low pressure pipe.

(Function) The pre-cooling refrigerator, etc. are housed in the freezer vacuum vessel, and the Juhr-Thomson valve, load absorption heat exchanger, etc. are housed in the load vacuum vessel, and both vessels are connected with flexible vacuum piping, and the freezing Since the circuit is connected by flexible high-pressure piping and low-pressure piping, it is possible to prevent the load absorption heat exchanger of the object to be cooled from being adversely affected by the vibrations and magnetic fields generated by the pre-cooling refrigerator, etc. can.

In addition, when disassembling and repairing a pre-cooling refrigerator, etc., first, the openings of the other pair of high-pressure inlet pipes and low-pressure inlet pipes are connected to the high-pressure side flow channels of the heat exchanger housed in separate refrigerator vacuum containers. and the low-pressure side flow path through flexible high-pressure piping and low-pressure piping, and the high-pressure stop valve and low-pressure stop valve arranged at the openings of the other pair of high-pressure inlet piping and low-pressure inlet piping are closed. Bypass valves disposed at the openings of the other pair of high-pressure inlet pipes and low-pressure inlet pipes are opened until a closed loop of only the other refrigerator is formed, and the operation of the other refrigerator is started. When the other refrigerator is sufficiently cooled, the high-pressure stop valve and low-pressure stop valve arranged at the openings of the other pair of high-pressure inlet pipes and low-pressure inlet pipes are opened, respectively, and the other pair of high-pressure inlet pipes and low-pressure Close the bypass valve arranged at the opening of the inlet pipe, and connect it to the high-pressure side flow path and low-pressure side flow path of the heat exchanger housed in the refrigerator vacuum container on the side of the refrigerator that was being operated earlier. the bypass valves disposed at the openings of one pair of high-pressure inlet piping and low-pressure inlet piping, and the high-pressure stop valve and low-pressure stop valve disposed at the openings of one pair of high-pressure inlet piping and low-pressure inlet piping Close the refrigerator to complete the switching of the refrigerator. After that, the refrigerator that was previously in operation is stopped, and the refrigerator is disconnected and disassembled for repair. Therefore, according to the above configuration, the load absorption heat exchanger in the load vacuum vessel is maintained at an extremely low temperature, that is, the precooling refrigerator is The pre-cooling refrigerator, etc. can be smoothly switched for disassembly and repair.

(Example) In Figures 1 and 2, 9 is a compressor;
2 is a buffer tank connected to the compressor; 1
is a three-stage precooling refrigerator; 2, 3, and 4 are precooling heat exchangers that contact each stage of the precooling refrigerator 1 for heat exchange; 5, 6, and 7 are countercurrent heat exchangers; The high-pressure side flow passages are pre-cooling heat exchangers 2, 3, 4 and 5, 2,
6, 3, 7, 4 are connected in this order, 24 is a purifier filled with activated carbon, etc., which is connected to the pre-cooling heat exchanger 4, 14 is the pre-cooling refrigerator 1, the pre-cooling heat exchangers 2, 3, 4, countercurrent type A refrigerator vacuum vessel containing the main parts consisting of heat exchangers 5, 6, 7 and a purifier 24, 8 is a J-T
A heat exchanger, 10 is a J-T valve, 11 is a liquid refrigerant container (11' is a load absorption heat exchanger), 13 is a liquid refrigerant immersed in liquid refrigerant in the liquid refrigerant container 11 (or a load absorption heat exchanger) 11') a cooled body in heat exchange contact with 11';
26 or 26' and 27 or 27' are respectively J
- The high-pressure inlet piping and low-pressure outlet piping of the T heat exchanger 8, 16 or 16' and 17 or 17', respectively, constitute a pair of high-pressure inlet piping 26 or 26'.
and a high pressure stop valve and a low pressure stop valve connected to the low pressure outlet pipe 27 or 27', 25 is the J-T heat exchanger 8
J connecting the high pressure inlet pipe 26 and the low pressure inlet pipe of
- T side bypass valve 18 or 18' is J-T side bypass valve 25 for high pressure stop valve 16 or 16';
A bypass valve 15 is located in the opposite position and is connected to the low pressure side, the J-T heat exchanger 8, the J-T valve 10, the liquid refrigerant container 11 (or the load absorption heat exchanger 11'),
Cooled body 13, J-T side bypass valve 25, high pressure pipes 26 and 26', low pressure pipes 27 and 27', high pressure stop valves 16 and 16', low pressure stop valves 17 and 1
7' and bypass valves 18 and 18'; 28 and 29 are a pair of high-pressure piping and low-pressure piping that penetrate the wall of the load vacuum container 15; A flexible high-pressure pipe 22 is a flexible low-pressure pipe connected to the low-pressure inlet of the countercurrent heat exchanger 7;
is a high pressure joint connecting high pressure pipes 21 and 28, 20
23 is a low pressure joint connecting low pressure pipes 22 and 29;
1 is a flexible vacuum pipe in which a high pressure pipe 21, a low pressure pipe 22, a high pressure joint 19, and a low pressure joint 20 are inserted, communicates with the refrigerator vacuum container 14, and is covered with the wall of the load vacuum container 15.

The operation of the above embodiment will be explained below.

The high pressure refrigerant supplied by the compressor 9 is cooled as it passes through the countercurrent heat exchangers 5, 6, 7 and the precooling heat exchangers 2, 3, 4 which are cooled by the precooling refrigerator 1.
It is purified in the purifier 24, passed through the flexible high-pressure pipe 21, high-pressure joint 19, high-pressure pipe 28, high-pressure stop valve 16, and high-pressure pipe 26, and further cooled in the J-T heat exchanger 8. The refrigerant is expanded and cooled by the T-valve 10, and a portion of the refrigerant is liquefied. The liquefied refrigerant transfers the object to be cooled 13 to the object to be cooled 1 by the heat of vaporization.
1 (or load absorption heat exchanger 11'), the refrigerant that has become a gas passes through the low pressure side of the J-T heat exchanger 8 and is heated by exchanging heat with the refrigerant from the high pressure side. , the low pressure piping 27, the low pressure stop valve 17, the low pressure piping 29, the low pressure joint 20, and the flexible low pressure piping 22 to the countercurrent heat exchanger 7, and countercurrent heat exchangers 7, 6, 5. While passing through the refrigerant, it is heated by exchanging heat with the refrigerant on the high pressure side, and enters the buffer tank 12.
Returning to the compressor 9, one refrigerant cycle is completed. In the above process, the bypass valves 18 and 1
8' and the J-T side bypass valve 25 are kept closed.
The J-T side bypass valve 25 mainly operates on the J-T side in the process of cooling the refrigeration system of the present invention from around normal temperature to extremely low temperature.
The heat exchanger 8 is used for rapid cooling, and the bypass valve 18 is open or the cryogenic part is already in operation (the object to be cooled 13 is cooled to a cryogenic temperature). It is also used when a separate pre-cooling refrigerator, etc. is connected and operated. In this case, connect the flexible high-pressure piping and low-pressure piping of the newly connected separate pre-cooling refrigerator to the high-pressure joint 1.
9' and low pressure joint 20', and attach vacuum piping. Then, the high pressure stop valve 16' and the low pressure stop valve 17' remain closed, and the bypass valve 18' is opened.
This newly connected separate pre-cooling refrigerator, etc. forms a closed loop and starts operation. After this newly installed and newly connected separate pre-cooling refrigerator etc. has sufficiently cooled down, open the high pressure stop valve 16' and low pressure stop valve 17', close the bypass valve 18', and then open the bypass valve 18. , the high pressure stop valve 16 and the low pressure stop valve 17 are closed to complete the switching. The pre-cooling refrigerator, etc. that were being operated earlier is stopped, the temperature is raised sufficiently, and then the vacuum piping 23 is removed to complete the separation of the pre-cooling refrigerator, etc. Note that the J-T side bypass valve 25 is opened as appropriate in order to maintain the J-T heat exchanger 8 at a low temperature when switching the above-mentioned pre-cooling refrigerator or the like.

FIG. 2 shows another modified embodiment of the present invention, in which the object to be cooled 13 is cooled by a heat exchanger 11' instead of the liquid refrigerant container 11 (load suction heat exchanger). In this example, the other configuration is the same as that of the embodiment shown in FIG.

In this way, the present invention separates the load-absorbing heat exchanger that cools the object to be cooled from the pre-cooling refrigerator, etc., and connects them with flexible piping, thereby applying vibrations and magnetic fields to the object to be cooled. In addition, it is possible to disassemble and repair the precooling refrigerator while maintaining the state in which the object to be cooled is cooled.

〔Effect of the invention〕

As described above, according to the present invention, the pre-cooling refrigerator etc. are housed in the refrigerator vacuum vessel, and the Juul-Thomson valve, the load absorption heat exchanger, etc. are housed in the load vacuum vessel, and both vessels have flexibility. Since the refrigeration circuit is connected by vacuum piping and flexible high-pressure piping and low-pressure piping, the load absorption heat exchanger of the object to be cooled will be adversely affected by the vibrations and magnetic fields generated by the pre-cooling refrigerator, etc. It is possible to avoid receiving

Further, according to the present invention, the load absorption heat exchanger in the load vacuum vessel is maintained at an extremely low temperature, that is, the precooling refrigerator, etc., is disassembled and repaired while flowing a refrigerant cooled to a low temperature through the load suction heat exchanger. Therefore, switching of the pre-cooling refrigerator, etc. can be performed smoothly.

In addition, in order to solve the technical problems of the present invention,
Only the liquid refrigerant container 11 is separated from the main part by flexible refrigerant piping and vacuum piping, and this refrigerant piping is provided with joints, stop valves, etc. in the same manner as in the present invention,
It is also possible to prevent the object to be cooled from being affected by vibrations and magnetic fields generated by the main part, and to replace the main part while the object to be cooled is still being cooled. but,
When using helium as the refrigerant, this
For transferring refrigerant at a temperature of 4K and a pressure of 1ata,
Although there is a problem in that heat entering from the outside directly leads to a decrease in the output of the refrigerant machine and significantly deteriorates the performance, the present invention solves the problem that
Even if heat intrudes into the heat exchanger 1 from the outside, it is cooled by the heat exchanger 8, so that the influence of this heat intrusion can be reduced, and the problem of significant deterioration of performance does not occur.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
The figure shows a circuit showing another modified embodiment of the present invention, and FIG. 3 is a circuit diagram of a conventional refrigeration system. 1... Pre-cooling refrigerator, 2, 3, 4... Pre-cooling heat exchanger, 5, 6, 7... Heat exchanger, 8... J-T heat exchanger (heat exchanger), 10... J- T-valve, 11...
Liquid refrigerant container (load absorption heat exchanger), 14... Refrigerator vacuum container, 15... Load vacuum container, 16... High pressure stop valve, 17... Low pressure stop valve, 18... Bypass valve, 21, 28... ...High pressure piping, 22, 29...
Low pressure piping, 23...vacuum piping, 26...high pressure inlet piping, 27...low pressure outlet piping.

Claims (1)

[Claims] 1. A pre-cooling refrigerator, a compressor that compresses refrigerant gas, a high-pressure side channel through which refrigerant gas discharged from the compressor flows and communicates with each other, and a high-pressure side flow path through which refrigerant gas sucked into the compressor flows and communicates with each other. A plurality of heat exchangers each having a low-pressure side flow path and exchanging heat between refrigerant gases flowing through each flow path, and interposed between the high-pressure side flow paths of the plurality of heat exchangers to achieve the precooling and freezing. a plurality of pre-cooling heat exchangers that pre-cool refrigerant gas using a machine;
a Joel-Thomson valve connected to the high-pressure side flow path of the heat exchanger located at the most downstream side of the high-pressure side flow paths of the plurality of heat exchangers to cause refrigerant gas to undergo Joel-Thomson expansion; In the Joel-Thomson refrigeration system comprising a valve and a load absorber interposed between a low-pressure flow path of the heat exchanger located most downstream, the heat exchanger located most downstream , the Joel-Thomson valve and the load absorber are housed in a load vacuum vessel, and the precooling refrigerator, the precooling heat exchanger, and the remaining plurality of heat exchangers are housed in a refrigerator vacuum vessel, and the A high-pressure inlet pipe having a plurality of inlets is connected to the high-pressure side flow path of the heat exchanger located on the most downstream side, and an inlet of the high-pressure inlet pipe is connected to the low-pressure side flow path of the heat exchanger located on the most downstream side. low pressure outlet pipes having the same number of outlet parts as the load vacuum container are connected to form a plurality of pairs of inlet/outlet parts that airtightly penetrate the load vacuum container, and one pair of the high pressure inlet pipe and the low pressure outlet part of the plurality of pairs of inlet/outlet parts are connected. The inlet/outlet portion of the outlet piping is connected to the high-pressure side flow path of the heat exchanger located at the most downstream side of the high-pressure side flow paths of the remaining heat exchangers through flexible high-pressure piping and low-pressure piping, respectively. and flexible vacuum piping connected to the low pressure side flow path, accommodating the high pressure piping and the low pressure piping between the refrigerator vacuum container and the load vacuum container, and vacuum-sealing the refrigerator vacuum container. A high-pressure stop valve and a low-pressure stop valve are interposed near the inlet and outlet portions of the plurality of pairs of high-pressure inlet pipes and low-pressure outlet pipes, respectively, and between each high-pressure stop valve and the outlet of each high-pressure pipe. A Jul-Thomson refrigeration system characterized in that a bypass valve is provided between each low-pressure stop valve and the inlet of each low-pressure pipe.