JP5926072B2 - Helium liquefier - Google Patents

Description

  The present invention relates to a helium liquefaction apparatus, and more particularly to a helium liquefaction apparatus in which a plurality of helium liquefiers are installed in one liquid helium storage tank.

  A helium liquefier for liquefying helium generally includes a compressor, a heat exchanger, an expansion turbine, a JT valve, a liquid helium storage tank, etc., and helium compressed to a high pressure by the compressor is about 6K. After being cooled to a temperature, a part of helium is liquefied by JT expansion (Joule Thompson expansion) using a JT valve, and the liquefied liquid helium is stored in a liquid helium storage tank. In such a helium liquefier, helium liquefaction is efficiently performed by detecting the temperature and pressure in a predetermined path and controlling opening and closing of a predetermined valve (see, for example, Patent Document 1). ). In this specification (including claims and abstract), liquid helium is expressed as liquid helium, but gaseous helium is simply expressed as helium.

JP 11-148735 A

  However, when multiple helium liquefiers, for example, two helium liquefiers are installed in one storage tank for redundancy in liquefaction of helium, the measuring instrument, controller, Due to the individuality of each device such as the controller, the same result may not be obtained even under the same conditions. Even if one helium liquefier maintains the specified operating state, the other helium liquefier is designed. There was a risk of falling into an inefficient driving state deviating from the point.

  Therefore, the present invention provides a helium liquefier that can maintain the operation state of each helium liquefier in a predetermined stable state when a plurality of helium liquefiers are installed in one storage tank. It is aimed.

In order to achieve the above object, the helium liquefier of the present invention is a compressor that compresses helium and sends it to a high-pressure path, and heat exchange that cools high-pressure helium in a high-pressure path by heat exchange with low-pressure helium returning in a low-pressure return path. A high temperature helium that is adiabatically expanded into a low-temperature low-pressure helium, a JT valve that JT-expands the high-pressure helium cooled by the heat exchanger, and liquid helium partially liquefied by JT expansion Liquid helium introduction path to be introduced into the helium storage tank, low pressure return path for circulating gaseous helium in the liquid helium storage tank from the heat exchanger to the compressor as the low pressure helium, and low pressure return from the liquid helium storage tank Helium liquefier equipped with return amount adjusting means for adjusting the amount of helium returning to the path according to the pressure in the liquid helium storage tank In the helium liquefaction apparatus in which a plurality of liquid helium storage tanks are installed in the liquid helium storage tank, a partition plate for partitioning the gas phase in the liquid helium storage tank is provided in the liquid helium storage tank to form a plurality of gas phase chambers. In addition, the one gas phase chamber divided is provided with the liquid helium introduction path, the low pressure return path, and the return amount adjusting means in one helium liquefier, and the gas phases of the plurality of gas phase chambers are arranged. It is characterized by providing communication means capable of communicating with each other .

Furthermore, the helium liquefaction apparatus of the present invention includes a compressor that compresses helium and sends it to a high-pressure path, a heat exchanger that cools high-pressure helium in a high-pressure path by heat exchange with low-pressure helium that returns in a low-pressure return path, An expansion turbine that partially expands adiabatically into low-temperature low-pressure helium, a JT valve that expands high-pressure helium cooled by the heat exchanger, and introduces liquid helium partially liquefied by JT expansion into the liquid helium storage tank Liquid helium introduction path, a low pressure return path for circulating gaseous helium in the liquid helium storage tank as the low pressure helium from the heat exchanger to the compressor, and helium returning from the liquid helium storage tank to the low pressure return path. A helium liquefier comprising return amount adjusting means for adjusting the amount in accordance with the pressure in the liquid helium storage tank. In the helium liquefaction apparatus installed in a plurality of helium storage tanks, a partition plate for partitioning the gas phase in the liquid helium storage tank is provided in the liquid helium storage tank, and a plurality of gas phase chambers are formed and partitioned. In one gas phase chamber, the liquid helium introduction path, the low pressure return path, and the return amount adjusting means in one helium liquefier are arranged, and the partition plate is formed so as to partition the entire liquid helium storage tank. The liquid communication part is provided in the lower part of the partition plate.

  According to the helium liquefaction apparatus of the present invention, since an independent gas phase chamber is formed for each helium liquefier in the liquid helium storage tank, the pressure of each gas phase chamber can be controlled independently, Helium returning to the low pressure return path without being liquefied by the JT valve can be circulated in each helium liquefier. Thereby, an amount of helium corresponding to the operating state of each helium liquefier can be returned to the low-pressure return path, and helium can be liquefied efficiently without being affected by the operating state of other helium liquefiers.

  Further, since the liquid phase and the vapor phase in the liquid helium storage tank are in communication with each other by communicating with the communicating means for communicating the gas phase chamber, the liquid can be obtained even if only one helium liquefier is operated. Helium can be stored in the entire helium storage tank, and liquid helium can be taken out from the liquid helium storage tank at one location. Furthermore, by providing a liquid communication part at the lower part of the partition plate in a state of partitioning the entire liquid helium storage tank, the partition plate can be easily manufactured and installed in the tank.

It is a systematic diagram which shows one example of a helium liquefying apparatus of this invention.

  The helium liquefier shown in the present embodiment is an apparatus in which a first helium liquefier 21 and a second helium liquefier 31 are installed in one liquid helium storage tank 11. A partition plate 12 is provided for partitioning. In the upper part of the tank, the first gas phase chamber 13a and the second gas phase chamber 13b are divided and formed by the partition plate 12 in an independent state. The lower part of the tank is provided in the lower part of the partition plate 12. The first liquid phase chamber 15a and the second liquid phase chamber 15b are partitioned and formed in communication with each other via the liquid communication portion 14. In addition, a communication pipe 16 capable of communicating the first gas phase chamber 13a and the second gas phase chamber 13b is provided in the upper portion of the tank, and both the gas phases are opened by opening the communication valve 17 provided in the communication pipe 16. The chambers 13a and 13b are formed so as to be in a communication state.

  Both helium liquefiers 21 and 31 have the same specifications and the same liquefaction capacity, and compress the helium and send it as high-pressure helium to the high-pressure paths 22 and 32; A plurality of heat exchangers 25 and 35 for cooling 32 high-pressure helium by heat exchange with low-pressure helium returning the low-pressure return paths 24 and 34 to the compressors 23 and 33, and a part of the high-pressure helium in the middle of cooling The high-pressure helium cooled by the heat exchangers 25 and 35, and a plurality of expansion turbines 26 and 36 that are low-temperature low-pressure helium by adiabatically expanding a part of the high-pressure helium branched by adjusting the flow rate by 26V and 36V. JT valves 27 and 37 for JT expansion, and liquid helium for introducing liquid helium partially liquefied by JT expansion in the JT valves 27 and 37 into the liquid helium storage tank 11 Introducing passages 28 and 38, the low-pressure return passages 24 and 34 for circulating gaseous helium in the liquid helium storage tank 11 as the low-pressure helium from the heat exchangers 25 and 35 to the compressors 23 and 33, and liquid helium Return amount adjusting means 29 and 39 for adjusting the amount of helium returning from the storage tank 11 to the low pressure return paths 24 and 34 according to the pressures of the liquid phase chambers 15a and 15b in the liquid helium storage tank 11, respectively. .

  Further, at the outlets of the expansion turbines 26 and 36, a temperature indicating controller (TIC) 27a that detects the temperature of low-pressure helium adiabatically expanded by the expansion turbines 26 and 36 and adjusts the opening degree of the JT valves 27 and 37. , 37a are provided. On the suction side and the discharge side of the compressors 23 and 33, unload paths 23a and 33a and load paths 23b and 33b connected to a buffer tank (not shown) are provided, respectively. Furthermore, liquid nitrogen (LN2) is supplied to the warm end sides of the heat exchangers 25 and 35 as auxiliary cold for cooling high-pressure helium.

  The return amount adjusting means 29, 39 are respectively provided on the cold end side of the heat exchangers 25, 35 by detecting the pressure in the gas phase chambers 13a, 13b by the pressure detecting means 29a, 39a, respectively. The opening of the control valve 29b and the second control valve 39b is adjusted. When the pressure in the gas phase chamber increases, the control valve is adjusted in the opening direction, and when the pressure in the gas phase chamber decreases, the control valve closes. Thus, the pressure in the gas phase chamber is maintained at a preset pressure.

  When both helium liquefiers 21 and 31 are operating in a stable state, for some reason, the pressure in the first gas phase chamber 13a corresponding to one helium liquefier, for example, the first helium liquefier 21, is slightly increased. When the pressure rises, the first control valve 29b is actuated in the opening direction by a signal from the pressure detecting means 29a to increase the amount of helium derived from the first gas phase chamber 13a, thereby reducing the pressure in the first gas phase chamber 13a. The first gas phase chamber 13a is lowered and held at a predetermined pressure.

  At this time, a slight increase in the pressure in the first gas phase chamber 13a is transmitted from the first liquid phase chamber 15a to the liquid helium in the second liquid phase chamber 15b through the liquid communication portion 14 due to the presence of the partition plate 12. Thus, the liquid helium in the second liquid phase chamber 15b is transmitted to the helium in the second gas phase chamber 13b, but the pressure increase in the first gas phase chamber 13a is completely transferred into the second gas phase chamber 13b. Before the transmission, the first control valve 29b opens and the pressure in the first gas phase chamber 13a decreases, so that the pressure in the second gas phase chamber 13b hardly increases and the second adjustment of the second helium liquefier 31 occurs. The valve 39b maintains the opening degree at that time and continues a stable operation state.

  On the other hand, when the partition plate 12 is not provided, the pressure of the entire gas phase of the liquid helium storage tank 11 is increased at the same time. Therefore, when the pressure of the first gas phase chamber 13a is slightly increased, the second helium liquefier 31 second The control valve 39b also operates in the opening direction at the same time as the first control valve 29b, and the operation state of the second helium liquefier 31 is disturbed. Furthermore, when the operational state disturbance of the second helium liquefier 31 affects the pressure of the entire gas phase of the liquid helium storage tank 11, both the helium liquefiers 21 and 31 become unstable, and the liquefaction efficiency of helium is increased. May decrease.

  Accordingly, by dividing the gas phase chambers 13a and 13b in the liquid helium storage tank 11 and arranging the helium liquefiers 21 and 31 for each of the gas phase chambers 13a and 13b, one pressure of each of the gas phase chambers 13a and 13b is obtained. Even if it rises or falls, it does not affect the other, and helium liquefiers 21 and 31 can be liquefied efficiently by making each helium liquefier 21 and 31 stable.

  Further, since the communication pipe 16 having the communication valve 17 is provided as a communication means for communicating the gas phase chambers 13a and 13b, the gas phase chambers 13a and 13b can be communicated by opening the communication valve 17. Since both the liquid phase chambers 15a and 15b communicate with each other through the liquid communication part 14, the gas phase and the liquid phase in the liquid helium storage tank 11 can be brought into communication with each other by opening the communication valve 17. it can. By communicating the gas phase and the liquid phase in this manner, the liquefied helium can be stored in the liquid helium storage tank 11 even if only one helium liquefier, for example, the first helium liquefier 21 is operated. The return amount adjusting means 29 is operated according to the pressure change in the gas phase of the entire liquid helium storage tank 11, and helium can be efficiently liquefied and stored by only one first helium liquefier 21.

  Further, by connecting both the gas phase chambers 13a and 13b, even when liquid helium is taken out from one place of the liquid helium storage tank 11, the pressure change and the liquid level change at the time of liquid helium extraction are simultaneously performed in the entire liquid helium storage tank 11. Therefore, the path for taking out liquid helium can be set at an arbitrary position in both liquid phase chambers 15a and 15b.

  The shape of the partition plate 12 and the structure of the liquid communication portion 14 can be arbitrarily set according to the shape and capacity of the liquid helium storage tank 11, and the liquid communication portion 14 can be formed by piping. The liquid communication portion 14 is formed by notching the lower edge portion of the plate member having an outer edge shape corresponding to the inner shape of the liquid helium storage tank 11 and partitioning the entire inside of the liquid helium storage tank or forming an opening. Thus, the partition plate 12 can be easily manufactured, and can be easily mounted in the liquid helium storage tank 11.

  In the above embodiment, two helium liquefiers with the same specifications are installed in one liquid helium storage tank. However, three or more helium liquefiers are divided into three or more chambers. It is also possible to install in one liquid helium storage tank, and it is also possible to install helium liquefiers with different specifications.

  DESCRIPTION OF SYMBOLS 11 ... Liquid helium storage tank, 12 ... Partition plate, 13a ... 1st gas phase chamber, 13b ... 2nd gas phase chamber, 14 ... Liquid communication part, 15a ... 1st liquid phase chamber, 15b ... 2nd liquid phase chamber, 16 ... Communication pipe, 17 ... Communication valve, 21 ... First helium liquefier, 22 ... High pressure path, 23 ... Compressor, 23a ... Unload path, 23b ... Load path, 24 ... Low pressure return path, 25 ... Heat exchanger, 26 ... Expansion turbine, 26V ... Control valve, 27 ... JT valve, 27a ... Temperature indicating controller, 28 ... Liquid helium introduction path, 29 ... Return amount adjustment means, 29a ... Pressure detection means, 29b ... First control valve, 31 2nd helium liquefier, 32 ... High pressure path, 33 ... Compressor, 33a ... Unload path, 33b ... Load path, 34 ... Low pressure return path, 35 ... Heat exchanger, 35V ... Control valve, 36 ... Expansion turbine, 37 ... JT valve, 37a ... Temperature indication Section meter, 38 ... liquid helium introducing path, 39 ... return amount adjustment means, 39a ... pressure detecting means, 39 b ... second regulating valve

Claims (2)

A compressor that compresses helium and sends it to the high-pressure path, a heat exchanger that cools the high-pressure helium in the high-pressure path by heat exchange with the low-pressure helium returning to the low-pressure return path, and a low-temperature, low-pressure by adiabatically expanding part of the high-pressure helium An expansion turbine for helium, a JT valve for JT expansion of high-pressure helium cooled by the heat exchanger, a liquid helium introduction path for introducing liquid helium partially liquefied by JT expansion into the liquid helium storage tank, and the liquid helium storage tank The amount of helium returning from the liquid helium storage tank to the low pressure return path and the amount of helium returning from the liquid helium storage tank according to the pressure in the liquid helium storage tank And a plurality of helium liquefiers equipped with return amount adjusting means for adjusting the liquid helium storage tank. In the lithium liquefier, a partition plate for partitioning the gas phase in the liquid helium storage tank is provided in the liquid helium storage tank to partition and form a plurality of gas phase chambers. The liquid helium introduction path, the low-pressure return path, and the return amount adjusting means in the two helium liquefiers are arranged, and communication means capable of communicating the gas phases of the plurality of gas phase chambers with each other is provided. Helium liquefier. A compressor that compresses helium and sends it to the high-pressure path, a heat exchanger that cools the high-pressure helium in the high-pressure path by heat exchange with the low-pressure helium returning to the low-pressure return path, and a low-temperature, low-pressure by adiabatically expanding part of the high-pressure helium An expansion turbine for helium, a JT valve for JT expansion of high-pressure helium cooled by the heat exchanger, a liquid helium introduction path for introducing liquid helium partially liquefied by JT expansion into the liquid helium storage tank, and the liquid helium storage tank The amount of helium returning from the liquid helium storage tank to the low pressure return path and the amount of helium returning from the liquid helium storage tank according to the pressure in the liquid helium storage tank And a plurality of helium liquefiers equipped with return amount adjusting means for adjusting the liquid helium storage tank. In the lithium liquefier, a partition plate for partitioning the gas phase in the liquid helium storage tank is provided in the liquid helium storage tank to partition and form a plurality of gas phase chambers. The liquid helium introduction path, the low pressure return path, and the return amount adjusting means in the two helium liquefiers are arranged, and the partition plate is formed in a state of partitioning the entire inside of the liquid helium storage tank, and is formed below the partition plate. features and to Ruhe potassium liquefier that Ekiren communicating portion is provided.

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