JP5639818B2 - Refrigeration liquefier and operation method of refrigeration liquefier - Google Patents

Description

  The present invention relates to a refrigeration liquefier and a method for operating the refrigeration liquefier, and more particularly to a refrigeration liquefier having a function of removing impurities in the refrigerant gas and purifying the refrigerant gas, and a method for operating the refrigeration liquefier.

  A refrigeration liquefaction machine, for example, a helium refrigeration liquefaction machine, includes a refrigeration liquefaction machine main body in which low-temperature equipment such as an expansion turbine and a JT valve that generate cold and a heat exchanger that recovers the generated cold are housed in a cold box, and refrigerant gas. A compressor that compresses certain helium and circulates it to the refrigeration liquefier main body; pressure control means for controlling the suction pressure and discharge pressure of the compressor to a constant pressure; and a gas storage container that stores helium. In addition, a purifier for removing impurities such as oxygen, nitrogen, and carbon dioxide in helium is provided (see, for example, Patent Document 1).

Japanese Patent Publication No. 7-21358

  However, in patent document 1, in order to refine | purify the refrigerant gas in a gas storage container with a refiner, it connects with the piping which connects a gas storage container and a refiner, and compression for circulating the refrigerant gas in a gas storage container to a refiner It is necessary to install an on-off valve for controlling the start and end of the refining machine for gas purification, leading to an increase in apparatus cost. In addition, if some pipes are formed so that they can also be used for purification, if the refrigerant gas purification is started while the refrigerant gas is circulated and supplied to the refrigeration liquefier main body, the pressure and flow around the compressor May become unstable and difficult to control, which may hinder the operation of the refrigeration liquefier body.

  Therefore, the present invention provides a refrigeration liquefier and a method of operating the refrigeration liquefier capable of purifying the refrigerant gas by circulating the refrigerant gas in the gas storage container to the purifier while continuing to circulate and supply the refrigerant gas to the refrigeration liquefier main body. It is intended to provide.

To achieve the above object, a refrigeration liquefier of the present invention comprises a compressor that compresses refrigerant gas from a refrigeration liquefier main body and circulates the refrigerant gas to the refrigeration liquefier main body, a discharge side and a suction side of the compressor A bypass path that connects to the compressor through a gas introduction path that has a load valve on the suction side of the compressor, and a gas lead-out path that has an unload valve on the discharge side of the compressor A gas storage container connected to the compressor, a gas purifier connected to the discharge side and the suction side of the compressor via a gas purification path, respectively, and the suction pressure of the compressor was detected to reduce the suction pressure. Sometimes the bypass valve is in the valve opening direction, and when the suction pressure rises, the suction pressure control means for controlling the bypass valve in the valve closing direction, and the discharge pressure of the compressor is detected and the discharge pressure decreases. Sometimes the unload valve A discharge pressure control means for controlling the load valve in the valve opening direction, closing the load valve and controlling the unload valve in the valve opening direction when the discharge pressure rises, the unload valve, and the It is characterized in that it comprises a purification operation control means for an open state bi side of the valve of the load valve.

  Further, the first configuration of the operation method of the refrigeration liquefier of the present invention includes a compressor that compresses refrigerant gas from the refrigeration liquefier main body and circulates the refrigerant gas to the refrigeration liquefier main body, a discharge side of the compressor, A gas lead-out having a bypass path connecting to the suction side via a bypass valve and a gas introduction path having a load valve on the suction side of the compressor and having an unload valve on the discharge side of the compressor A gas storage container connected via a path, a gas purification path connecting a discharge side and a suction side of the compressor via a gas purifier, and a suction pressure of the compressor is detected to reduce the suction pressure The suction valve control means for controlling the bypass valve in the valve opening direction when the suction valve rises and the valve closing direction when the suction pressure increases, and the discharge pressure of the compressor is reduced by detecting the discharge pressure of the compressor When the load valve is opened Operation of the refrigeration liquefaction machine comprising discharge pressure control means for closing the unload valve by closing the unload valve and controlling the unload valve in the valve opening direction when the discharge pressure rises The refrigerant gas to the refrigeration liquefier main body is controlled by a cooling operation control that closes the other valve when either the unload valve or the load valve is open. While the circulation supply is continued, the refrigerant gas in the gas storage container is circulated to the gas purifier by switching to the purification operation control for opening the unload valve and the load valve.

  Furthermore, the second configuration of the operation method of the refrigeration liquefier of the present invention includes a compressor that compresses the refrigerant gas from the refrigeration liquefier main body and circulates the refrigerant gas to the refrigeration liquefier main body, and a discharge side of the compressor. A gas lead-out having a bypass path connecting to the suction side via a bypass valve and a gas introduction path having a load valve on the suction side of the compressor and having an unload valve on the discharge side of the compressor A gas storage container connected via a path, a gas purification path connecting a discharge side and a suction side of the compressor via a gas purifier, and a suction pressure of the compressor is detected to reduce the suction pressure The suction valve control means for controlling the bypass valve in the valve opening direction when the suction valve rises and the valve closing direction when the suction pressure increases, and the discharge pressure of the compressor is reduced by detecting the discharge pressure of the compressor When the load valve is opened Operation of a refrigeration liquefaction machine comprising discharge pressure control means that closes the unload valve by controlling in the direction and controls the unload valve in the valve opening direction to close the load valve when the discharge pressure rises The refrigerant gas to the refrigeration liquefier main body is controlled by a cooling operation control that closes the other valve when either the unload valve or the load valve is open. While the circulation supply is being continued, when one valve is opened, the control is switched to the refining operation control that opens the other valve that should be closed, and the refrigerant gas in the gas storage container is changed. It is characterized by circulating in the gas purifier.

  According to the present invention, it is possible to purify the refrigerant gas by circulating the refrigerant gas stored in the gas storage container to the gas purifier while continuing to circulate and supply the refrigerant gas to the refrigeration liquefier main body.

1 is a system diagram of a refrigeration liquefier showing a first embodiment of the present invention. It is a figure explaining the opening degree control of the load valve in a 1st example, and an unload valve. It is a systematic diagram of a refrigeration liquefier showing a second embodiment of the present invention. It is a figure explaining the opening degree control of the load valve in a 2nd example, and an unload valve.

  1 and 2 show a first embodiment of the present invention. The refrigeration liquefier shown in this embodiment includes an expansion turbine and JT valve that generate cold, a heat exchanger that recovers the generated cold, and the like. Refrigeration liquefier main body 11 in which low-temperature equipment is stored in a cold box, and refrigeration liquefier main body with high-pressure refrigerant gas (HP) compressed by suctioning low-pressure refrigerant gas (LP) from the refrigeration liquefier main body 11 11, a compressor 12 for circulating supply to the gas, a gas storage container 13 for storing the refrigerant gas, a purifier 14 for removing impurities that solidify at a low temperature such as oxygen, nitrogen, carbon dioxide in the refrigerant gas, The bypass path 15 connecting the discharge side path 12a and the suction side path 12b of the compressor 12 via a bypass valve 15V, and the discharge side path 12a of the compressor 12 and the gas storage container 13 are unloaded valves 16V. Through A gas lead-out path 16 to be connected, a gas introduction path 17 for connecting the suction side path 12b of the compressor 12 and the gas storage container 13 via a load valve 17V, and the purifier 14 to the discharge side of the compressor 12 The refining paths 14a and 14b are respectively connected to the path 12a and the suction side path 12b, the suction pressure control means 18 for keeping the suction pressure of the compressor 12 constant, and the discharge pressure of the compressor 12 constant. And a discharge pressure control means 19 for maintaining.

  The discharge pressure control means 19 is a signal output according to the discharge pressure detected by the discharge side pressure detection means (PIC1) 21 for detecting the discharge pressure of the compressor 12 and the control target value (MV value (instrumentation term MV value ( Manipulated Value), hereinafter referred to as “operation output”), the unload valve 16V and the load valve 17V are set to be split-controlled. In such control, since the bypass flow is exclusively formed in the bypass valve 15V, the characteristic shown by the broken line in FIG. 2 is given, and both the flow rate of the load valve 17V and the flow rate of the unload valve 16V are both stable. Usually, the operation output is set to 50% so as to be zero. In addition, in order to suppress disturbance due to the occurrence of a minute flow in the load valve 17V and the unload valve 16V, the load valve 17V and the unload valve 16V are closed when the operation output of the discharge side pressure detecting means 21 is near 50%. A dead zone for maintaining the state is often provided. For example, if the operation output at the pressure at which both the unload valve 16V and the load valve 17V are closed is set to 50% and the dead zone width is set to 10%, the operation output is 50% to 45% to 55%. The range of becomes a dead zone. Although FIG. 2 illustrates an operation line for performing control including the dead zone, in the following description, since the numerical value becomes complicated, the dead zone is described as 0%.

  The split control of the unload valve 16V and the load valve 17V by the discharge pressure control means 19 is 0 to 100% of the operation output 0 to 100% of the discharge side pressure detection means 21, as indicated by broken lines in each drawing of FIG. In the range of 50%, the unload valve 16V is kept in the closed state (opening degree 0%), and the load valve 17V is in the fully open state (opening degree 100%) with the operation output 0%, and the operation output 50% or more. The valve open state is controlled linearly so that the fully closed state (opening degree 0%) is obtained. On the other hand, the unload valve 16V is linearly controlled to open from 0% to 100% in a fully closed state with an operation output of 50% or less and in the range of 50 to 100% of operation output.

  As described above, the discharge pressure control means 19 that performs the split control in which the unload valve 16V and the load valve 17V are set so that the other valve is closed when one of the valves is open. The control for cooling operation in which the operation is performed by the split control and the control for purification operation for performing the purification operation of the refrigerant gas in the system are set to be switchable. In the control for refining operation, when controlling the valve open state of the load valve 17V in the range of 0 to 50% of the operation output of the discharge side pressure detecting means 21, the unload valve 16V that should be fully closed in the split control. Is controlled so as to maintain the valve open state up to a preset range, and when the operation output of the discharge side pressure detecting means 21 is in the range of 50 to 100%, the valve open state of the unload valve 16V is controlled. In the split control, the load valve 17V, which should be fully closed, is controlled so as to be kept open to a preset range.

In the normal cooling operation control, the opening degree A [%] of the load valve 17V indicated by the broken line Va in FIG. 2A has a slope a with respect to the operation output MV [%] of the discharge side pressure detecting means 21. When the intercept is expressed by b [%], it is set so as to be controlled by the following equation, and when the obtained value of A becomes negative, it is in the fully closed state (opening degree 0%).
A = a × MV + b = −2 × MV + 100

Similarly, the opening B [%] of the unload valve 16V indicated by the broken line Vc in FIG. 2B is c with respect to the operation output MV [%] of the discharge side pressure detection means 21 and d is the intercept. When expressed in [%], it is set to be controlled by the following equation, and when the obtained value of B becomes negative, it is in a fully closed state (opening degree 0%).
B = c × MV + d = 2 × MV−100

  In the purification operation control, the slopes a and c of the unload valve 16V and the load valve 17V are changed at a constant ratio. The load valve 17V has an operation output of the discharge side pressure detecting means 21 of 50%. The unload valve 16V is set so as to maintain the valve open state even when the operation output of the discharge side pressure detecting means 21 falls below 50%. However, the intercept d of the unload valve 16V is set so as to pass through a point where the operation output of the discharge side pressure detecting means 21 is 100% and the opening degree of the unload valve 16V is 100%.

In the load valve 17V, the value of the slope a is changed to the slope a1 used in the purification operation control. For example, as shown by the solid line Vb in FIG. 2A, the operation output of the discharge side pressure detecting means 21 is 100. The inclination a1 used in the control for the refinement operation is set to −1 so that the opening degree of the load valve 17V becomes 0% (closed state) when it reaches nearly%. The control of the load valve 17V in the purification operation control is performed by the following equation.
A = a1 × MV + b = −1 × MV + 100

Similarly, in the control of the unload valve 16V, for example, as shown by the solid line Vd in FIG. 2B, the slope c is changed to the slope c1 used in the control for the refinement operation, and the intercept d is the same as that described above. As described above, the intercept d1 passes through a point where the operation output of the discharge side pressure detecting means 21 is 100% and the opening degree of the unload valve 16V is 100%. When the inclination c1 is made to correspond to the inclination a1 of the load valve 17V and a1 = −c1, a1 = −1, so c1 = 1. The control of the unload valve 16V in the purification operation control is performed by the following equation.
B = c1 * MV + d1 = 1 * MV-0

  By setting the refining operation control in this way, when the operation output of the discharge side pressure detecting means 21 is 50%, the opening degrees of the unload valve 16V and the load valve 17V are both about 50%.

  When the refrigeration liquefier performs stable operation in the steady state by the cooling operation control, the compressor 12 sucks a substantially constant amount of low-pressure refrigerant gas, and the high-pressure refrigerant gas compressed by the compressor 12 is A substantially constant amount is supplied to the refrigeration liquefier main body 11, and excess high-pressure refrigerant gas is circulated to the suction side of the compressor 12 through the bypass path 15. In this stable operation state, the suction pressure and the discharge pressure of the compressor 12 hardly change, the operation output of the discharge-side pressure detection means 21 is about 50%, and both the unload valve 16V and the load valve 17V are fully closed ( Opening 0%), the bypass valve 15V is in a state of maintaining a substantially constant opening.

  When the cooling operation control is switched to the refining operation control, the discharge pressure control means 19 changes the inclinations a and c used in the cooling operation control to the inclinations a1 and c1 used in the refining operation control. At this time, if the inclination is suddenly changed, the suction pressure and the discharge pressure of the compressor 12 may be disturbed. Therefore, it takes a preset time, for example, 30 minutes, or the opening degree changes by 1% per minute. Thus, the inclination is gradually controlled from a, c to a1, c1.

  When the discharge pressure control means 19 is switched to the refining operation control in this manner, the unload valve 16V and the load valve 17V are in a substantially half open state (opening degree of about 50%), so that the discharge side path 12a of the compressor 12 A portion of the discharged high-pressure refrigerant gas flows through the gas outlet path 16 toward the gas storage container 13 due to a pressure difference, and the refrigerant gas stored in the gas storage container 13 flows into the high-pressure refrigerant gas that has flowed in. Is pushed out from the gas storage container 13 to the gas introduction path 17 and is sucked into the compressor 12 through the suction side path 12b.

  At the same time, a part of the high-pressure refrigerant gas flows into the purifier 14 from the discharge side path 12a via the purification path 14a, and after being purified by the purifier 14, the compressor 12 passes from the purification path 14b through the suction side path 12b. Inhaled. The high-pressure refrigerant gas discharged from the compressor 12 during the refining operation control includes the low-pressure refrigerant gas (LP) from the refrigeration liquefier main body 11, the refrigerant gas circulated from the bypass path 15, and the gas Since the refrigerant gas from the storage container 13 merges with the refrigerant gas, a part of the refrigerant gas from the gas storage container 13 contained in the merged refrigerant gas passes through the purifier 14. Accordingly, various conditions for the purification operation control are set according to conditions such as the volume and pressure of the gas storage container 13 and the amount of refrigerant gas passing through the purifier 14, and the purification operation control is continued for a preset time. As a result, the entire amount of the refrigerant gas in the system including the inside of the gas storage container 13 can be purified by the purifier 14.

  In addition, a part of the high-pressure refrigerant gas circulates through the gas storage container 13 to the compressor 12, and the amount of refrigerant gas sucked by the compressor 12 increases and the suction pressure of the compressor 12 increases. The suction pressure control means 18 controls the bypass valve 15V in the valve closing direction based on the increase of the suction pressure detected by the suction side pressure detection means (PIC2) 22, and the amount of refrigerant gas circulated through the bypass path 15 is determined. By reducing it, the suction pressure of the compressor 12 is kept constant. Thus, by keeping the suction pressure and discharge pressure of the compressor 12 constant, the refrigerant gas of a predetermined pressure and flow rate is supplied to the refrigeration liquefier main body 11 in a stable state and circulated.

  Thus, by incorporating the purification operation control means for performing the purification operation control into the discharge pressure control means 19, when one of the unload valve 16V and the load valve 17V is in the open state, the other is closed. The control for cooling operation is simply switched to the control for refining operation that controls one valve in the valve opening direction and simultaneously controls the other valve in the valve closing direction so that both the unload valve 16V and the load valve 17V are opened. Thus, the refrigerant gas can be circulated in the gas storage container 13 by using the gas lead-out path 16 and the gas introduction path 17, and the refrigerating machine main body 11 can be recirculated without requiring another compressor or piping for purification. The entire amount of the refrigerant gas in the system can be introduced into the purifier 14 and purified while continuing the circulation and supply of the refrigerant gas. Thereby, the purification process of the refrigerant gas can be performed with almost no increase in equipment cost and operation cost. In addition, since the unload valve 16V and the load valve 17V are controlled to open and close according to the discharge pressure of the compressor 12, even if the amount of refrigerant gas circulating through the refrigeration liquefier main body 11 fluctuates due to the load fluctuation of the refrigeration liquefier main body 11. Since the unload valve 16V and the load valve 17V are controlled to open and close in a related state, it is possible to follow the load fluctuation of the refrigeration liquefier main body 11.

  The purifier 14 may continuously purify a part of the refrigerant gas even when the cooling operation control is performed, and operates only during the purification operation control to operate the refrigerant gas. Some purifiers may be used, and various purifiers are used if they greatly affect the suction pressure and discharge pressure of the compressor 12 when switching between the cooling operation control and the purification operation control. be able to.

  3 and 4 show a second embodiment of the present invention, and the same components as those of the refrigeration liquefier shown in the first embodiment are denoted by the same reference numerals and are described in detail. Is omitted.

  In the present embodiment, purification operation control is performed in which one of the unload valve 16V and the load valve 17V is disconnected from the split control and is opened at a preset opening degree. For example, as shown in FIG. 3, a switch 24 is provided for switching the opening / closing control of the unload valve 16V between the discharge pressure control means 19 and the refining operation control means 23. The switch 24 is connected to the discharge pressure control means 19 as shown in FIG. Then, the refrigerant gas is purified by switching to the control means 23 for purification operation.

  In normal cooling operation control by the discharge pressure control means 19, the load valve 17V has a predetermined output in the range of 0 to 50% of the operation output of the discharge side pressure detection means 21, as shown by the solid line Va in FIG. In the valve open state, as shown by the solid line Vc in FIG. 4B, the unload valve 16V is in the predetermined valve open state in the range of the operation output of 50 to 100%, and in the other ranges, it is in the valve closed state. It is controlled to become.

  When the switch 24 is switched to the refining operation control means 23, as shown by the solid line Ve in FIG. 4C, the unload valve 16V takes a preset time, for example, an opening, for example, an opening. The valve is gradually opened toward 70%, and purification operation control is performed to maintain the opening degree of 70% until the switch 24 is switched to the cooling operation control S.

  When the unload valve 16V is opened, a part of the high-pressure refrigerant gas discharged to the discharge side passage 12a of the compressor 12 flows through the gas outlet passage 16 toward the gas storage container 13 due to a pressure difference. The discharge pressure of the compressor 12 detected by the discharge-side pressure detection means 21 decreases according to the amount of refrigerant gas flowing into the gas storage container 13. When the operation output falls below 50%, the discharge pressure control means 19 is activated, the opening of the load valve 17V is controlled based on the operation output by the split control, and the refrigerant stored in the gas storage container 13 A predetermined amount of gas is introduced into the suction side passage 12 b of the compressor 12 through the gas introduction passage 17.

  Thus, while the unload valve 16V is held open by the refining operation control means 23, the load valve 17V is controlled by the discharge pressure control means 19 to open according to the discharge pressure. An amount of refrigerant gas corresponding to the amount of refrigerant gas flowing into the gas storage container 13 from the compressor 12 through the gas outlet path 16 passes through the load valve 17V and the gas introduction path 17 from the gas storage container 13. Sucked into. Accordingly, a part of the refrigerant gas is circulated through the gas storage container 13 and another part of the refrigerant gas is circulated through the purifier 14, so that the refrigerant gas is the same as in the first embodiment. Is purified. Further, since the suction pressure control means 18 controls the bypass valve 15V according to the amount of refrigerant gas circulating through the gas storage container 13, the suction pressure and discharge pressure of the compressor 12 are controlled by the suction pressure control means 18 and the discharge pressure control means 19. The pressure is kept constant, and a predetermined amount of refrigerant gas is supplied to the refrigeration liquefier main body 11 and circulated.

  Further, when the load valve 17V is set to be opened by the refining operation control instead of the unload valve 16V, the gas in the gas storage container 13 is transferred to the gas introduction path by opening the load valve 17V. Since the amount of refrigerant gas sucked into the compressor 12 through 17 and compressed by the compressor 12 increases, the pressure of the discharge side passage 12a rises, so that the operation output of the discharge side pressure detecting means 21 is 50%. The discharge pressure control means 19 controls the unload valve 16V in the valve opening direction based on the operation output, and a part of the refrigerant gas discharged from the compressor 12 passes through the unload valve 16V to become gas. It flows into the storage container 13. Therefore, in this case as well, the refrigerant gas discharged from the compressor 12 is partially circulated through the gas storage container 13 and the other part is circulated through the purifier 14. Is done. Also at this time, the suction pressure control means 18 controls the bypass valve 15V to keep the suction pressure of the compressor 12 constant, so that a predetermined amount of refrigerant gas is supplied to the refrigeration liquefier main body 11 and circulates. The state can be continued.

  DESCRIPTION OF SYMBOLS 11 ... Refrigerator main body, 12 ... Compressor, 12a ... Discharge side path, 12b ... Inhalation side path, 13 ... Gas storage container, 14 ... Purifier, 14a, 14b ... Purification path, 15 ... Bypass path, 15V ... Bypass Valve, 16 ... gas outlet path, 16V ... unload valve, 17 ... gas introduction path, 17V ... load valve, 18 ... suction pressure control means, 19 ... discharge pressure control means, 21 ... discharge side pressure detection means (PIC1), 22 ... suction side pressure detection means (PIC2), 23 ... purification control means, 24 ... switch

Claims (3)

A compressor that compresses refrigerant gas from the refrigeration liquefier main body and circulates the refrigerant gas to the refrigeration liquefier main body; a bypass path that connects a discharge side and a suction side of the compressor via a bypass valve; and the compressor A gas storage container connected to a suction side of the compressor via a gas introduction path having a load valve and connected to a discharge side of the compressor via a gas outlet path having an unload valve, and a discharge side of the compressor And a gas purifier connected to the suction side through a gas purification path, and when the suction pressure of the compressor is detected and the suction pressure decreases, the bypass valve is opened and the suction pressure increases. A suction pressure control means for controlling the bypass valve in a closing direction when detected, and detecting the discharge pressure of the compressor and closing the unload valve and opening the load valve when the discharge pressure decreases Control the direction of the discharge A discharge pressure control means for controlling said unloading valve to close the load valve when the force rises in the valve opening direction, purification of the valve of the twin sides of the unloading valve and the load valve an open state A refrigeration machine comprising a control means for use.   A compressor that compresses refrigerant gas from the refrigeration liquefier main body and circulates the refrigerant gas to the refrigeration liquefier main body; a bypass path that connects a discharge side and a suction side of the compressor via a bypass valve; and the compressor A gas storage container connected via a gas introduction path having a load valve to the suction side of the compressor and a gas outlet path having an unload valve to the discharge side of the compressor, and a discharge side of the compressor A gas purification path connecting the suction side with a gas purifier, and when the suction pressure of the compressor is detected and the suction pressure is reduced, the bypass valve is opened and the suction pressure is increased. Suction pressure control means for controlling the bypass valve in the valve closing direction, and detecting the discharge pressure of the compressor, and controlling the load valve in the valve opening direction when the discharge pressure is reduced, the unload valve Close the discharge pressure An operating method of a refrigeration liquefier comprising discharge pressure control means for controlling the unload valve in the valve opening direction and closing the load valve when the valve rises, wherein either the unload valve or the load valve While the circulation supply of the refrigerant gas to the refrigeration liquefier main body is continued by the control for cooling operation in which the other valve is closed when one valve is open, the unload valve and the load valve are A method of operating a refrigeration liquefier, wherein the refrigerant gas in the gas storage container is circulated to the gas purifier by switching to the refining operation control to be opened.   A compressor that compresses refrigerant gas from the refrigeration liquefier main body and circulates the refrigerant gas to the refrigeration liquefier main body; a bypass path that connects a discharge side and a suction side of the compressor via a bypass valve; and the compressor A gas storage container connected via a gas introduction path having a load valve to the suction side of the compressor and a gas outlet path having an unload valve to the discharge side of the compressor, and a discharge side of the compressor A gas purification path connecting the suction side with a gas purifier, and when the suction pressure of the compressor is detected and the suction pressure is reduced, the bypass valve is opened and the suction pressure is increased. Suction pressure control means for controlling the bypass valve in the valve closing direction, and detecting the discharge pressure of the compressor, and controlling the load valve in the valve opening direction when the discharge pressure is reduced, the unload valve Close the discharge pressure An operating method of a refrigeration liquefier comprising discharge pressure control means for controlling the unload valve in the valve opening direction and closing the load valve when the valve rises, wherein either the unload valve or the load valve While one of the valves is in the open state, one of the valves is in the open state while the refrigerant gas is continuously being circulated and supplied to the refrigeration liquefier main body by the control for cooling operation that closes the other valve. The refrigerant liquefier is characterized in that the refrigerant valve in the gas storage container is circulated to the gas purifier by switching to the refining operation control in which the other valve that should be in a closed state is opened. how to drive.

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