JPS58210478A - Helium liquefier - 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]

The present invention relates to a helium liquefaction device for liquefying helium gas. Conventional helium liquefaction equipment uses multiple heat exchangers, helium expansion turbines, and Joule/Thomson valves to convert the introduced low-temperature, high-pressure helium gas into liquefied gas and liquefy it. The helium liquefaction mechanism discharges helium gas to the outside, and the helium gas discharged from the helium liquefaction structure is compressed by riE under a crystal using a piston type or screw compressor, and the compressed helium gas is 80° by appropriate means
It is common to have a helium compression system that cools the helium to about K and returns it to the helium liquefaction system. However, in the fake helium configuration, the helium is discharged from the helium liquefaction mechanism, compressed by the compressor, and then turned into I￥i again.
During the circulation, the helium gas introduced into the helium liquefaction mechanism is heated in a trench from room temperature to about 300 degrees, and becomes a huge volume. There are many inconveniences such as increase in weight and weight. In addition, the piston-type and squirter-type fake compressors mentioned in n11 and 17 have the problem of low reliability due to ring wear and oil contamination with the helium gas.21 In addition, such helium liquefaction equipment In order to pre-cool the helium gas introduced into the liquefaction mechanism, liquid nitrogen is mainly However, in conventional systems, liquid nitrogen and the like are all supplied from outside the device. Therefore, there is the inconvenience of having to install a button near the helium liquefaction device and a large tank for storing liquid nitrogen. The present invention has been developed in view of these circumstances, and is capable of introducing and compressing low-temperature, low-pressure helium gas discharged from a helium liquefaction mechanism into a fusial compressor without raising the temperature to room temperature. The radial compressor is driven by a turbine that is rotated by a high-pressure fishing gas made of nitrogen or air.
Furthermore, by energizing the turbine 1) 11
To provide a helium liquefaction device capable of completely eliminating the above-mentioned disadvantages by liquefying a part of the Oi++ gas by utilizing the phenomenon that the temperature of the Oi++ gas decreases. There is a conflict. Hereinafter, one embodiment of the present invention will be described with red-eye α of the drawings. 1 in the figure is a helium liquefaction mechanism. Helium liquefaction mechanism 1
is the low temperature (about 8 o' K) introduced from the inlet 1a,
High-pressure (about 10 to 16 ata) helium gas is liquefied using a multi-internal heat exchanger (not shown), a helium expansion turbine, a joule drainer, a Thomson-knoll, etc. The helium liquefaction mechanism is designed to be discharged sequentially from outlet 1b, and has the same structure as the conventional one.Helium gas at a temperature of about 80° is discharged from outlet 1b of this helium liquefaction mechanism. is introduced into the radial compressor 3 through the 1 m passage 2, and the helium gas compressed by the radial compressor 3 is rotated at a moderate speed so as to introduce the helium gas compressed by the radial compressor 3 through the passage 4 into the inlet 1alc of the helium liquefaction system 10 described in III. The impeller 3a is driven by the turbine 6.The high-pressure zero nitrogen gas discharged from the nitrogen compressor 7 is sent to the main high-pressure gas line 8f; The turbine 6 is rotated at a high speed by blowing nitrogen gas every 1ft to the turbine 6 as a working gas. An aftercooler 9, an adsorber 11, and a heat exchanger 12 are interposed in the middle of the mud gas line 8 (71).The nitrogen gas supply line 13 is connected to the upstream portion of the main high-pressure gas line 8. At the same time, an auxiliary high-pressure Ganu thread path 17 is branched from the downstream portion by sequentially interposing the first and 201st heat exchangers 14, 15 and the Joule-Thomsonder 16. Nitrogen gas expanded and cooled by passing through the turbine 6 ii
The gas is returned to the nitrogen compressor 7 via the main low pressure gas line 18 provided to pass through the heat exchanger 142. and e main high pressure gas line 18
The sub low pressure gas line 19 is branched from the upstream portion of the auxiliary low pressure gas line 19, and the sub low pressure gas line 19 is passed through a heat exchanger 20 interposed near the end of the Ail compression line 5. It merges into the middle section of the main low pressure ts system path 186j. On the other hand, the portion of the auxiliary high-pressure gas line 17 in which the heat exchanger 14, 15 and the Joule-Thompson valve 16 are interposed is housed in a heat insulating container (not shown) to constitute the nvJ gas liquefaction mechanism 21. That is, the working gas liquefaction mechanism 21 has n
11 The end of the auxiliary high pressure gas line 17 is opened into the dewar bottle 22 for storing liquid nitrogen, and the nitrogen gas in the dewar bottle 22 is passed through the m1 heat exchanger 15. 1°Ii

[An exhaust line 23 for discharging gas is provided upstream a++ of the mud low-pressure gas system line 18. Next, the operation of this device will be explained. When the high pressure nitrogen gas discharged from the compressor 7 without being separated is led to the turbine 6 through the main high pressure gas line 8,
This e-turbine 6 rotates at high speed, thereby putting the radial compressor 3 into operation. As a result, the helium gas at a low temperature of about 80 degrees discharged from the helium liquefaction mechanism 1 is directly led to the radial compressor 3, compressed in a low temperature environment, and passes through the heat exchanger 20. The helium liquefier I is pre-cooled to a temperature of 80c'.
Returned to Ml. Therefore, a well-known liquefaction action takes place within the helium liquefaction mechanism, and the helium gas is successively liquefied. At this time, the nitrogen gas flowing in the main high-pressure gas line 8 marked m1 exchanges heat with the low-temperature nitrogen gas in the main low-pressure gas line 18 when passing through the heat exchanger 12, and the temperature is reduced from room temperature to llo'. It is cooled down to a temperature of about 80 degrees, and further expanded by passing through the turbine 6 to a temperature of about 80 degrees. Then, this nitrogen gas oils the main low pressure gas line 18 and the auxiliary low pressure gas line 19 and is returned to the compressor 7 and circulated again. On the other hand, the high-pressure nitrogen gas introduced into the secondary high-pressure gas line 17 undergoes heat exchange with the low-temperature nitrogen gas in the main low-pressure gas line 111 when connecting the heat exchanger 14. Te 80
When passing through the heat exchanger 17, it exchanges heat with the low-temperature nitrogen gas in the button thread path 23, and is cooled to below the reversal temperature. Therefore, the nitrogen gas in this secondary high pressure gas line 17 is removed from the Joule-Thompson valve 1.
When it is freely expanded through the pipe 6, a part of it is liquefied and stored in the dewar bottle 22, and the low-temperature nitrogen gas that cannot be liquefied is sent to the discharge line 23. The liquid nitrogen generated in the dewar bottle 22 is discharged into the main low-pressure gas line 18 through the passage 1-.Then, the liquid nitrogen generated in the dewar bottle 22 is led out of the bottle via a pumping line h (not shown). 1 Qil E helium liquefaction mechanism 1
It is used to cool the heat shield of the heat insulating wall surrounding the helium liquefier, various equipment, or to pre-cool the helium gas q introduced into the helium liquefaction mechanism (m:I). Note that the working gas for driving the turbine is not limited to nitrogen, and may be dry air. Furthermore, the number of radial compressors for compressing helium is not limited to one stage, but may be provided in two or more stages. Since the present invention has the above configuration, the following effects can be obtained. First, the low-temperature helium gas discharged from the helium liquefaction mechanism is directly compressed by a compressor, and can be reintroduced into the helium liquefaction mechanism without raising the temperature to room temperature. It becomes something like that, and there is no area at all. Therefore, i3J's capability is to significantly reduce the size and weight of the surface fishing rod. Further, since the helium gas is compressed in a low temperature environment, a sufficient compression effect can be obtained even when a Radia I recombiner is used for warping work. In other words, in order to obtain a sufficient compression ratio in a radial compressor, it is necessary to rotate the impeller at a speed such that its outer circumference approaches the speed of sound, but if it is operated with warpage at room temperature, it, M This is almost impossible because extremely large centrifugal stress acts on the impeller. However, when compressing helium gas at a low temperature of about 80° K,
Because the speed of sound decreases in proportion to the square root of absolute temperature,
It becomes possible to easily obtain a high compression ratio using a radial compressor. 1. Furthermore, if a radial compressor is used, there will be no oil mist mixed into the helium gas, and there will be no piston ring wear, so the overall reliability and durability of the device can be improved. Furthermore, since the radial compressor is driven by a rotating turbine by being driven by a high-pressure working gas made of nitrogen or air, it can achieve the desired high speed. It is possible to get rotation. Furthermore, by utilizing the phenomenon that the temperature of the working gas Q decreases by energizing the turbine Il+, a portion of the working gas Q can be liquefied, so that the heat shield of the heat insulating wall inside the equipment is used. and cooling of various equipment,
In other words, it is possible to sequentially create a liquid reservoir or liquid air used for pre-cooling helium gas, etc. Therefore,
There is no need to install a large tank outside the device to supply liquid nitrogen, etc. to each part of the equipment.

[Brief explanation of the drawing]

The drawing is a circuit explanatory diagram showing one embodiment of the present invention. 1... Helium liquefaction mechanism 3... Radial compressor 5... Helium compression line 6... Turbine 7... Gas source (compressor )8...
Main high pressure gas line 16...- Joule-Thompson valve 17...
・Sub-high pressure gas line 18...Low pressure gas line 21...Representative of working gas liquefaction mechanism Patent attorney Hiroshi Akazawa

Claims (1)

[Claims] A helium liquefaction mechanism that liquefies the introduced low-temperature, high-pressure helium gas and discharges the low-temperature, low-pressure a helium gas that cannot be liquefied to the outside, and the low-temperature helium gas discharged from this helium liquefaction mechanism is directly radially compressed. A helium compression system that compresses it with a compressor and introduces it into the helium liquefaction mechanism, a turbine for driving the radial compressor, and a high-pressure working gas consisting of nitrogen or voids discharged from a gas source @ A main high-pressure gas line that supplies the turbine; a sub-high-pressure gas line branched from the main high-pressure gas line; A low temperature gas system that is exhausted while exchanging heat with the working gas in the system;
A helium liquefaction device characterized by comprising a working gas liquefaction mechanism that liquefies the false high-pressure working gas in the subpolymer gas system using a Joule-Thompson valve! .