JPH0523351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a helium refrigeration system used for cooling superconducting magnets, cryopumps, etc., for example.

[Technical background of the invention and its problems]

As shown in FIG. 2, this type of helium refrigeration system that has already been proposed compresses helium with a main compressor 1, liquefies it in a cold box device (helium liquefaction device) 2, and converts the liquefied helium into is supplied to each refrigeration load body 5a, 5b, 5c and liquid helium tank 6 through each branch pipe 4a, 4b, 4c, 4d covered with a long insulated tube (transtube) 3, and each refrigeration load body 5a, 5b and 5c, the helium is cooled by heat exchange, and the helium that has completed its work is transferred to the helium recovery and purification system 7, after which gas helium is circulated and supplied to the main compressor 1. .

That is, in FIG. 2, a first heat exchanger (liquid nitrogen heat exchanger) 8 constituting a cold box device (helium liquefaction device) 2 is connected to a helium supply system 7 of a main compressor 1 in a helium refrigerator. This first heat exchanger 8 is connected to a nitrogen supply pipe 9.
The high-pressure gas helium is heat-exchanged with liquid nitrogen from the reactor, turning it into a high-pressure, low-temperature gas, and the liquid nitrogen that has completed its work is vaporized and refluxed. On the other hand, a second heat exchanger 10 and a Joel-Thomson valve 11 are connected to the helium supply system 7 on the downstream side of the first heat exchanger 8, and on the downstream side of the Joel-Thomson valve 11, The liquid helium tank 6 and each refrigeration load body 5a, 5b, 5c are connected through each branch pipe 4a, 4b, 4c, 4d covered with a long heat insulating pipe (transfer tube) 3.

The liquid helium tank 6 is connected to each of the refrigeration loads 5a, 5b, and 5c via helium supply pipes 12. Further, a bypass path 1 is provided between the inlet side and the outlet side of the second heat exchanger 10.
3a is connected, and an expander 13 is attached to this bypass path 13a. Furthermore, each of the refrigeration loads 5a, 5b, 5c and the main compressor 1 are connected by a return pipe 14, and a helium recovery and purification system 21 is installed in the return pipe 14. In addition, each of the above-mentioned refrigeration load bodies 5a, 5b, 5
c and the main compressor 1 are connected by a reflux pipe 15 passing through the second heat exchanger 10.

Therefore, the helium refrigeration system described above compresses gas helium by driving the main compressor 1, and converts it to high pressure in the first heat exchanger 8 and second heat exchanger 10 that constitute the cold box device 2. A cryogenic gas helium is produced and then passed through a Joel-Thomson valve 11 to expand the gas helium to produce cryogenic liquid helium.
Although some of this liquid helium is stored in the liquid helium tank 6, most of the liquid helium is supplied to each of the refrigeration loads 5a, 5b, and 5c, where it is used for heat exchange with, for example, a superconducting magnet. After cooling, part of the gas helium that has completed its work is transferred to the main compressor 1 through the helium recovery and purification system 21 in the return pipe 14, while the remaining helium is transferred to the main compressor 1 through the reflux pipe 15. It is starting to be supplied again.

In the helium refrigeration system described above, the helium recovery and purification system 21 may be omitted, a helium purifier may be attached to the main compressor 1, or the liquid helium tank 6 may be omitted. Moreover, the main compressor 1 and the cold box device 2 in the helium refrigeration system described above
The capacity is determined by taking into consideration the heat loss of the Joel-Thompson valve (low-temperature valve 11 and long insulated pipe 3) provided on the inlet side of each refrigeration load body 5a, 5b, 5c.

However, the helium refrigeration device described above,
Since the cold box device 2 is connected to the plurality of refrigeration loads 5a, 5b, and 5c by the helium supply pipe 7, and the insulated pipe 3 is covered with an expensive transfer tube, the length of the cold box device 2 is several tens of meters to several
If the insulated pipe 3 is covered with a length of about 100m,
Not only does the heat loss of the helium in the helium supply pipe 7 increase, but also the heat exchange efficiency decreases, and the piping of the heat insulating pipe 3 becomes long, making it economically expensive.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and involves connecting each cold box device directly to a plurality of refrigerating loads to shorten the transfer distance of liquid helium and reduce heat loss. The present invention provides a helium refrigeration system that aims to improve the heat exchange efficiency and also shortens the length of the insulated pipes so that the piping can be installed economically.

[Summary of the invention]

The present invention connects a helium supply system to the main compressor, connects each cold box device to each refrigeration line branched from this helium supply system, and covers each cold box device and each refrigeration load with an insulated pipe. each refrigeration load body and the main compressor are connected via each connecting pipe with a return pipe,
This return pipe is equipped with a helium recovery and purification system.

[Embodiments of the invention]

Hereinafter, the present invention will be described with reference to an illustrated embodiment.

It should be noted that the present invention will be described with the same reference numerals attached to the same constituent members as in the above-described specific example. In FIG. 1, reference numeral 1 denotes a main compressor in a helium refrigerator, and a helium supply system 7 on the discharge side of the main compressor 1 includes refrigerant lines 7a, 7b, 7.
The refrigerant lines 7a, 7b, 7c are connected to cold box devices (helium liquefaction devices) 16a, 16b, 16c. Moreover, each cold box device 16a, 16b, 16c and each refrigeration load body 5a,
5b, 5c are connecting pipes 17a, 17b, 17c and 19a, 19 that cover the short heat insulating pipe 18.
The refrigeration loads 5a, 5b, 5c and the main compressor 1 are connected by a return pipe 14 via each connecting pipe 20a, 20b, 20c. A helium recovery and purification system 21 is installed in the pipe 14 .

Each of the cold box devices (helium liquefaction devices) 16a, 16b, and 16c exchanges heat with liquid nitrogen from the nitrogen supply pipe 9 to convert high-pressure gas helium into high-pressure low-temperature gas, as shown in FIG. First heat exchanger 8, second heat exchanger 10, expander 1
3 and a Joel-Thomson valve 11 that generates cryogenic liquid helium.

Therefore, by driving the main compressor 1, gas helium is compressed, and it is passed through the helium supply system 7 and each refrigerant line 7a, 7b, 7c to each cold box device 16a, 16b, 16c to convert it into cryogenic liquid helium. generate. Then, this liquid helium is supplied to each refrigeration load body 5a, 5b, 5c through each connecting pipe 17a, 17b, 17c,
The gas helium that worked here and finished its work,
The helium is transferred to the main compressor 1 through the helium recovery and purification system 21 of each of the connecting pipes 20a, 20b, 20c and the return pipe 14.

In addition, some helium of each of the above-mentioned refrigeration loads 5a, 5b, 5c is supplied to each connecting pipe 19a, 19b, 19.
The main compressor 1 is supplied again through the reflux pipe 15 and the reflux pipe 15.

In this way, each of the cold box devices 16
a, 16b, 16c and each refrigeration load body 5a, 5b,
5c means each shortened connecting pipe 17a, 17b, 1
7c, 19a, 19b, and 19c, the heat insulating pipes 18a, 18b, and 18c are shortened, reducing heat loss by shortening the transfer distance of liquid helium, and improving heat exchange efficiency. It is planned.

〔Effect of the invention〕

As described above, according to the present invention, the main compressor 1
A helium supply system 7 is connected to the helium supply system 7, and each refrigerant line 7a, 7b, 7c branched from this helium supply system 7.
Each cold box device 16a, 16b, 16
c, and each cold box device 16
a, 16b, 16c and each refrigeration load body 5a, 5b,
5c and each connecting pipe 17a covered with the heat insulating pipe 18,
17b and 17c, each refrigerating load body 5
a, 5b, 5c and the main compressor 1 are connected to each connecting pipe 20.
connected by a return pipe 14 via a, 20b, 20c,
Since this return pipe 14 is provided with a helium recovery and purification system 21, it is possible not only to shorten the transfer distance of liquid helium and reduce heat loss, but also to improve heat exchange efficiency. Economical piping can be achieved by shortening the length of the pipe.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a helium refrigeration system according to the present invention, and FIG. 2 is a system diagram of a helium refrigeration system that has already been proposed. 1... Main compressor, 5a, 5b, 5c... Refrigeration load body, 7... Helium supply system, 7a, 7b, 7c
... Refrigerant line, 14 ... Return pipe, 16a, 16
b, 16c...cold box device, 17a,
17b, 17c... Connection pipe, 18... Heat insulation pipe, 2
1... Helium recovery and purification system.

Claims (1)

[Claims] 1. A helium supply system is connected to the main compressor, each cold box device is connected to each refrigeration line branched from this helium supply system, and each cold box device and each refrigeration load are insulated. The pipes are connected by covered connecting pipes, each of the refrigeration loads and the main compressor are connected via each connecting pipe with a return pipe, and a helium recovery and purification system is provided in the return pipe. Helium refrigeration equipment. 2. The cold box device is a bypass system in which a first heat exchanger, a second heat exchanger, and a Joel-Thomson valve are connected to a helium supply system, and expanders are provided on the upstream and downstream sides of the second heat exchanger. The helium refrigeration system according to claim 1, further comprising a passage.