JP2017172813A - Cryogenic cooling apparatus and cryogenic cooling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cryogenic cooling apparatus and a cryogenic cooling method capable of precooling while reducing the amount of cryogenic liquid used.SOLUTION: The cryogenic cooling apparatus comprises: a cryostat; a main cooling system for cooling a superconducting coil by using a refrigerant gas in a cryogenic refrigerator; an auxiliary cooling system for cooling the superconducting coil using liquid helium; and a control unit for controlling a supply amount of the refrigerant gas and the liquid helium. The auxiliary cooling system comprises: a cooling pipe provided in contact with the outside of the superconducting coil for passing the liquid helium therethrough; a cooled-object temperature measuring unit provided in contact with the outside of a cooled object for measuring a temperature of the cooled object; an outflow liquid measuring unit for measuring a temperature of the liquid helium; and a flow regulating valve for regulating the supply amount of the liquid helium to be supplied to the cryostat. The opening degree of the flow regulating valve is regulated based on measurement results of the cooled-object temperature measuring unit and the outflow liquid measuring unit so that the supply amount of the liquid helium to the cooling pipe is controlled.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a cryogenic cooling device and a cryogenic cooling method.

  Superconducting wire has the characteristics of zero resistance and allows high current density to flow, so power equipment such as generators and power cables, power storage devices, high magnetic field generators (superconducting magnets), MRI devices (magnetic) (Resonance imaging apparatus), heavy particle beam cancer treatment apparatus and other healthcare equipment, single crystal pulling apparatus, high magnetic field NMR (nuclear magnetic resonance) and the like. In addition, superconducting wires are expected to be applied to various fields such as magnetic levitation trains and magnetic separation devices.

  In these devices, for example, a superconducting wire is wound and used as a superconducting coil. This superconducting coil is a critical element that depends on the ambient magnetic field and the energizing current density in order to achieve the characteristics of zero resistance and high current density. It is necessary to cool to a very low temperature below the temperature. For example, the superconducting coil is used after being cooled to about 4K (−269 ° C.), for example. Cooling methods for industrial superconducting equipment such as superconducting coils include immersion cooling in which industrial superconducting equipment is immersed in liquid helium, and cryogenic refrigerators and industrial superconducting equipment connected via a heat transfer material. There is a conduction cooling system.

  When cooling a superconducting coil using the immersion cooling method, if there is an increase in the thermal load of the superconducting coil or a cryogenic refrigerator breaks down, even if the temperature of the superconducting coil rises, It can be said that it is excellent in that it can absorb the increase in heat load.

  Therefore, for example, a method for stably cooling the superconducting coil by detecting the liquid level or pressure level of liquid helium in the heat insulating container and adjusting the supply amount of liquid helium has been proposed.

Japanese Patent Laid-Open No. 6-221696

  Here, since the price of liquid helium is rising due to depletion of helium, etc., it is required to reduce the amount of liquid helium used in order to reduce the operating cost of the cryogenic cooling device. Therefore, there is a need for a cryogenic cooling device that can efficiently use liquid helium for cooling a superconducting coil or the like while reducing the amount of liquid helium used.

  Therefore, the problem to be solved by the present invention is to provide a cryogenic cooling device and a cryogenic cooling method capable of efficiently cooling an object to be cooled while reducing the amount of cryogenic liquid used.

  A cryogenic cooling device according to an embodiment includes a cryostat including a heat insulating container for containing an object to be cooled, a vacuum container containing the heat insulating container inside, and a refrigerant using a cryogenic refrigerator. A main cooling system that cools the object to be cooled with gas, a sub-cooling system that cools the object to be cooled using a cryogenic liquid, and a control unit that controls the supply amount of the refrigerant gas and the cryogenic liquid; The sub-cooling system is provided in a state of being in contact with the outside of the object to be cooled, the cooling pipe through which the cryogenic liquid passes, and the object to be cooled A cooled object temperature measuring unit for measuring the temperature of the cooled object provided in contact with the outside, and a discharge side of the cryogenic liquid from a portion of the cooling pipe that is in contact with the cooled object The temperature of the cryogenic liquid provided in the And a flow rate adjusting valve for adjusting a supply amount of the cryogenic liquid supplied to a portion in contact with the object to be cooled. The amount of the cryogenic liquid supplied to the cooling pipe is controlled by adjusting the opening of the flow rate adjusting valve based on the measurement results of the object temperature measuring unit and the effluent liquid measuring unit.

  A cryogenic cooling apparatus according to another embodiment uses a cryostat including a heat insulating container surrounding the object to be cooled, a vacuum container containing the heat insulating container, and a cryogenic refrigerator. A main cooling system for cooling the object to be cooled by the refrigerant gas, a sub-cooling system for cooling the object to be cooled by using a cryogenic liquid, and a control unit for controlling the supply amount of the refrigerant gas and the cryogenic liquid; The subcooling system is provided in a state of being in contact with the outside of the object to be cooled, the cooling pipe through which the cryogenic liquid passes, and the object to be cooled Branched from the cooling pipe through which the cryogenic liquid supplied to the pipe passes and contacts the outside of the heat insulating container, and connected to the cooling pipe through which the cryogenic liquid exchanged with the object to be cooled passes. Branched cooling pipe and the object to be cooled An object temperature measuring unit for measuring the temperature of the object to be cooled provided to be in contact with the outside, and a temperature in the heat insulating container provided to be in contact with the outside of the heat insulating container are measured. Supplyed to the branch cooling pipe provided in the cooling pipe, a flow rate adjusting valve for adjusting a supply amount of the cryogenic liquid supplied to a portion in contact with the object to be cooled, a container temperature measuring section, A flow control valve that adjusts the flow rate of the cryogenic liquid, and a control unit that controls the flow control valve or the flow control valve based on the measurement results of the container temperature measurement unit and the cooled object temperature measurement unit; The control unit adjusts the opening degree of the flow rate adjusting valve or the diversion adjusting valve based on the measurement result of the object to be cooled temperature measuring unit or the container temperature measuring unit, and the cooling pipe or the The cryogenic liquid to the branch cooling pipe The amount of feed is controlled.

  A cryogenic cooling method according to another embodiment uses a cryostat including a heat insulating container surrounding the object to be cooled, a vacuum container containing the heat insulating container, and a cryogenic refrigerator. A main cooling system that cools the object to be cooled with a refrigerant gas, and a sub-cooling system that cools the object to be cooled using a cryogenic liquid that passes through a cooling pipe provided in contact with the outside of the object to be cooled. A step of supplying the cryogenic liquid to the cooling pipe, cooling the object to be cooled with the cryogenic liquid, and measuring the temperature of the object to be cooled. And measuring the temperature of the cryogenic liquid discharged from the cryostat, based on the measurement result of the temperature of the object to be cooled and the temperature of the cryogenic liquid discharged from the cryostat. The above Controlling the supply amount of the cryogenic liquid to 却管.

  A cryogenic cooling method according to another embodiment uses a cryostat including a heat insulating container surrounding the object to be cooled, a vacuum container containing the heat insulating container, and a cryogenic refrigerator. A main cooling system that cools the object to be cooled with a refrigerant gas, and a sub-cooling system that cools the object to be cooled using a cryogenic liquid that passes through a cooling pipe provided in contact with the outside of the object to be cooled. Using the cryogenic cooling device comprising: the cooling pipe or the cooling pipe through which the cryogenic liquid supplied to the object to be cooled branches and comes into contact with the outside of the heat insulating container The cryogenic liquid is supplied to a branch cooling pipe connected to the cooling pipe through which the cryogenic liquid exchanged with the object to be cooled passes, and the object to be cooled or the heat insulating container is connected to the cryogenic liquid. Cooling with Measuring the temperature of the reject or the insulated container, and based on the temperature result of the cooled object or the insulated container, the amount of the cryogenic liquid supplied to the cooling pipe or the branch cooling pipe Control.

  According to the present invention, by controlling the supply amount of the cryogenic liquid, the usage amount of the cryogenic liquid released without heat exchange can be reduced, and thus the usage amount of the cryogenic liquid is reduced. The object to be cooled can be efficiently cooled.

It is a schematic sectional drawing which shows the structure of the cryogenic cooling device by 1st Embodiment. It is a figure which shows an example of the opening-and-closing state of a flow regulating valve, a gas discharge valve, and a gas supply valve. It is a figure which shows another example of the opening / closing state of a flow regulating valve, a gas discharge valve, and a gas supply valve. It is a schematic sectional drawing which shows the structure of the cryogenic cooling device by 2nd Embodiment. It is a figure which shows an example of the open / close state of a flow regulating valve and a shunt regulating valve. It is a figure which shows another example of the opening / closing state of a flow regulating valve and a shunt regulating valve. It is a schematic sectional drawing which shows the structure of the cryogenic cooling device by 3rd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. For ease of understanding, the scale of each member in the drawings may be different from the actual scale. In the following description, one of the cryogenic cooling devices in the height direction may be referred to as “upper” or “upper”, and the other of the cryogenic cooling devices in the height direction may be referred to as “lower” or “lower”.

(First embodiment)
The cryogenic cooling device according to the first embodiment will be described. FIG. 1 is a schematic cross-sectional view showing the configuration of the cryogenic cooling device according to the first embodiment. As shown in FIG. 1, the cryogenic cooling device 10 </ b> A includes a cryostat 11, a cryogenic refrigerator 12, a cooling pipe 13, an object temperature measuring unit 14, an effluent liquid measuring unit 15, and a control unit 16. The cryostat 11 includes a superconducting coil 17 as an object to be cooled, which is obtained by using a superconducting wire. The cryogenic cooling device 10 </ b> A uses, as means for cooling the superconducting coil 17, a main cooling system A that cools the superconducting coil 17 with the refrigerant gas 18 using the cryogenic refrigerator 12, and liquid helium 19 as the cryogenic liquid. A sub-cooling system B that cools the superconducting coil 17, and in the main cooling system A, the superconducting coil 17 is heat-exchanged with the refrigerant gas 18 cooled to a cryogenic temperature, and cooled to a cryogenic temperature of about 4K, for example. doing.

  In this embodiment, the superconducting coil 17 is used as the object to be cooled, but a superconducting element or the like may be used. Further, although liquid helium 19 is used as the cryogenic liquid, liquid nitrogen or the like can also be used. For example, in general, when cooling an object to be cooled from room temperature to about 80K, liquid nitrogen is used, and 80K to 4K. Liquid helium is used for cooling to the extent.

  The cryostat 11 includes a heat insulating container 21 formed of a heat shield plate and a vacuum container 22.

  The heat insulating container 21 is formed so as to surround the periphery of the superconducting coil 17. The heat insulating container 21 is cooled by the first cooling stage 31, and heat transfer into the heat insulating container 21 is reduced. Since the second cooling stage 32 of the cryogenic refrigerator 12 is cooled to about 4K, for example, the superconducting coil 17 in the heat insulating container 21 is held at 4K, for example.

The vacuum container 22 contains the heat insulating container 21 and the first cooling stage 31 of the cryogenic refrigerator 12 inside, and the inside of the vacuum container 22 is evacuated to insulate the vacuum. The inside of the vacuum vessel 22 is held at normal temperature (for example, about 300K). A cryogenic refrigerator 12 is supported in a vacuum container 22. In the present embodiment, the vacuum means a state in which the inside of the vacuum vessel 22 is reduced to a pressure close to a vacuum, and the degree of vacuum (internal pressure) in the vacuum vessel 22 is reduced to 10 ⁻³ Pa or less. Say.

  The main cooling system A is a cooling system including a cryogenic refrigerator 12, and the sub cooling system B is a cooling pipe 13, a to-be-cooled object temperature measuring unit 14, an effluent liquid measuring unit 15, and flow rate adjusting valves V11 and V12. Is a cooling system. Hereinafter, each member constituting the cryogenic cooling device 10A will be described while explaining the main cooling system A and the sub cooling system B.

(Main cooling system A)
The main cooling system A includes a cryogenic refrigerator 12, and the superconducting coil 17 is cooled by the refrigerant gas 18 in the cryogenic refrigerator 12.

  The cryogenic refrigerator 12 cools the superconducting coil 17 and has a first cooling stage 31 and a second cooling stage 32. The cryogenic refrigerator 12 is provided to be supported by the vacuum vessel 22, the first cooling stage 31 is provided in contact with the heat insulating vessel 21, and the second cooling stage 32 is provided in contact with the superconducting coil 17. ing. The cooling pipe 13 is provided on the outer periphery of the superconducting coil 17, but the second cooling stage 32 is provided in contact with the superconducting coil 17 at a place where the cooling pipe 13 is not installed. Alternatively, the second cooling stage 32 may be installed on the cooling pipe 13 to cool the superconducting coil 17 via the cooling pipe 13. In the present embodiment, the main cooling system A is provided with a compressor (compressor) 34 that compresses the refrigerant gas 18 after cooling the superconducting coil 17. The refrigerant gas 18 circulates through the cryogenic refrigerator 12 and the compressor 34 via a supply pipe 35. The refrigerant gas 18 after cooling the superconducting coil 17 is sent to the compressor 34 via the supply pipe 35 and compressed. As the refrigerant gas 18, helium gas or the like is used. In the compressor 34, the refrigerant gas 18 is preferably compressed to a pressure of about 2.0 MPa, for example. When the refrigerant gas 18 is helium gas, the helium gas has a large heat capacity if the pressure is within the above range when the temperature is about 20K. Therefore, the superconducting coil 17 can be stably cooled to a very low temperature. it can.

  The refrigerant gas 18 compressed by the compressor 34 is supplied into the cryogenic refrigerator 12 through the supply pipe 35. As the refrigerant gas 18 flows through the cryogenic refrigerator 12, the heat insulating container 21 is cooled by the first cooling stage 31, and the amount of heat entering the heat insulating container 21 is reduced. The second cooling stage 32 is cooled to about 4K, for example, and the superconducting coil 17 is held at about 4K by the second cooling stage 32, for example. The refrigerant gas 18 expands in the cryogenic refrigerator 12 and reaches, for example, about 0.8 MPa, and is returned to the compressor 34.

(Sub cooling system B)
The sub cooling system B includes a cooling pipe 13, an object temperature measuring unit 14, an outflow liquid measuring unit 15, and flow rate adjusting valves V <b> 11 and V <b> 12, and the superconducting coil 17 is cooled by the liquid helium 19.

  The cooling pipe 13 is a pipe through which liquid helium 19 can pass, and the supply port 13 a and the discharge port 13 b of the cooling pipe 13 are disposed outside the cryostat 11. The cooling pipe 13 is provided in contact with the outside of the superconducting coil 17. As long as the cooling pipe 13 can be brought into contact with the outside of the superconducting coil 17 to cool the superconducting coil 17, the method of installing the cooling pipe 13 is not particularly limited. For example, a plurality of cooling pipes 13 are brought into contact with the outside of the superconducting coil 17. It can be wound around. Since the second cooling stage 32 is cooled to about 4K, for example, the superconducting coil 17 is heat-exchanged with the liquid helium 19 via the cooling pipe 13 and cooled to about 4K. The cooling pipe 13 is preferably made of, for example, copper, aluminum, or a copper or aluminum alloy as a material having good thermal conductivity in order to sufficiently reduce the thermal resistance of the pipe wall.

  The cooling pipe 13 is provided with flow rate adjusting valves V <b> 11 and V <b> 12 to adjust the supply amount of liquid helium 19 supplied to the cryostat 11. In the present embodiment, the cooling pipe 13 is provided with both the flow rate adjusting valves V11 and V12. However, only the flow rate adjusting valve V11 located on the inflow side of the liquid helium 19 is provided in the cooling pipe 13. Also good.

  Liquid helium 19 is injected into the cooling pipe 13 from the cryogenic liquid injection part 41. The cryogenic liquid injection part 41 includes a dewar 42 in which the liquid helium 19 is accommodated, and a transfer tube 43 that supplies the liquid helium 19 from the dewar 42 to the cooling pipe 13. The upper space in the dewar 42 includes a safety valve 44, a gas exhaust valve 45, and a gas introduction valve 46. The gas introduction valve 46 communicates with a helium gas cylinder 47 that contains helium gas. The dewar 42 is provided with a manually operated valve 48, and the manually operated valve 48 is provided in a guide tube 49 that supplies the liquid helium 19 stored in the liquid helium 19 to the cooling tube 13. The guide tube 49 is arranged so that the other end is located in the liquid helium 19 accommodated in the dewar 42. One end side of the transfer tube 43 is connected to the outlet of the guide tube 49 via an insertion and fastening type connecting portion 50A. The transfer tube 43 includes a metal inner tube and a metal outer tube, and is formed in a double tube structure having a vacuum heat insulating layer between the inner tube and the outer tube. It is connected to the cooling pipe 13 via the connecting portion 50B. That is, the transfer tube 43 has an inlet side connected to the outlet of the guide tube 49 and an outlet side connected to the inlet of the cooling tube 13. The transfer tube 43 is provided with an inflow liquid sensor 43a, and the temperature, flow rate, pressure, etc. of the liquid helium 19 passing through the transfer tube 43 are measured. When the liquid helium 19 stored in the dewar 42 is pressurized with helium gas in the helium gas cylinder 47, the liquid helium 19 is supplied from the dewar 42 to the cooling pipe 13 through the transfer tube 43. In the present embodiment, the inflow liquid sensor 43a is provided in the transfer tube 43. However, the installation location of the inflow liquid sensor 43a is not limited to this. For example, the inflow liquid sensor 43a is provided in the vicinity of the inlet side of the cooling pipe 13 and transferred. The temperature, flow rate, pressure, or the like of the liquid helium 19 supplied from the tube 43 to the cooling pipe 13 may be measured.

  The to-be-cooled object temperature measuring unit 14 is provided in the superconducting coil 17 and measures the temperature of the superconducting coil 17. The temperature of the superconducting coil 17 is preferably about 4K, for example.

  The effluent liquid measurement unit 15 is provided on the discharge side of the liquid helium 19, that is, on the outlet side of the vacuum vessel 22 with respect to the portion of the cooling pipe 13 that is in contact with the superconducting coil 17, and the liquid discharged from the cryostat 11. The temperature of helium 19 is measured.

  The control unit 16 includes poles such as an object temperature measurement unit 14, an outflow liquid measurement unit 15, a compressor 34, flow rate adjustment valves V 11 and V 12, an inflow liquid sensor 43 a, a safety valve 44, a gas exhaust valve 45, and a gas introduction valve 46. It is connected to each member constituting the low temperature cooling device 10A. The control part 16 can be comprised including the memory | storage means to store a control program and various memory | storage information, and the calculating means which operate | moves based on a control program, for example. The control unit 16 stores in advance a map indicating the relationship between the temperature of the superconducting coil 17 and the temperature of the liquid helium 19 discharged from the cryostat 11 in the storage means, and uses the map information. You may control. Based on the measurement results of the temperature of the superconducting coil 17 obtained by the cooled object temperature measuring unit 14 and the temperature of the liquid helium 19 obtained by the outflow liquid measuring unit 15, the control unit 16 determines the cooling state of the superconducting coil 17, The state of the liquid helium 19 is determined, and the opening degree of the flow rate adjusting valves V11 and V12 is adjusted, or the supply amount of the liquid helium 19 to the cooling pipe 13 is controlled. In this embodiment, the opening degree of the flow rate adjusting valves V11 and V12 is adjusted depending on the temperature of the superconducting coil 17 and whether or not the liquid helium 19 discharged from the cooling pipe 13 is in liquid, gas, or a mixed state thereof. Is done. For example, when the temperature of the superconducting coil 17 is about 4K, the temperature of the liquid helium 19 discharged from the cooling pipe 13 is also about 4K, and the liquid helium 19 is discharged from the cooling pipe 13 in a liquid state, the superconducting It is determined that the temperature difference between the liquid helium 19 discharged from the coil 17 and the cooling pipe 13 is small (for example, 1K or less). In this case, it can be said that the flow rate of the liquid helium 19 supplied to the cooling pipe 13 is large while the superconducting coil 17 is cooled to about 4K. Therefore, it is determined that the liquid helium 19 is discharged from the cooling pipe 13 without much use for heat exchange with the superconducting coil 17, and the control unit 16 reduces the opening of the flow rate adjustment valve V11 to reduce the cooling pipe. The flow rate of the liquid helium 19 supplied to 13 is controlled to be small.

  Next, an example of a cryogenic cooling method for cooling the superconducting coil 17 to an extremely low temperature, for example, about 4K, using the cryogenic cooling device 10A will be described. In FIGS. 2 and 3, the flow control valves V11 and V12 that are indicated in white indicate that the valves are open, and those that are indicated in black are closed. Means that

  In the cryogenic cooling device 10A, when the cryogenic cooling device 10A is in a normal operation state such as when the superconducting coil 17 is cooled to a cryogenic temperature, the control unit 16 performs compression as shown in FIG. An instruction to start the operation of the machine 34 and an instruction to close the flow rate adjusting valves V11 and V12 are sent. At this time, in the cryogenic cooling device 10 </ b> A, the refrigerant gas 18 is pressurized by the compressor 34 and then supplied to the cryogenic refrigerator 12, and the used refrigerant gas 18 is discharged from the cryogenic refrigerator 12. The supply pipe 35 is circulated. The first cooling stage 31 of the cryogenic refrigerator 12 is cooled to about 20K to 50K (for example, 30K) by the refrigerant gas 18 supplied to the cryogenic refrigerator 12, and the second cooling stage 32 is 4K. It is cooled to a very low temperature. Therefore, the heat insulating container 21 is cooled by the first cooling stage 31, and the amount of heat entering the heat insulating container 21 is reduced. The second cooling stage 32 is cooled to about 4K. By conducting and cooling the superconducting coil 17 by the second cooling stage 32, the superconducting coil 17 is cooled to about 4K to 6K (for example, 4K), and is insulated. The container 21 is hold | maintained at about 20K-50K (for example, 40K).

  Next, at the start of operation of the cryogenic cooling device 10A, or after the superconducting coil 17 is at room temperature or after quenching (when the superconducting phenomenon disappears), the temperature of the superconducting coil 17 has risen and needs to be cooled to a very low temperature that can be excited. 3, the control unit 16 sends an instruction to open the flow rate adjusting valves V11 and V12 while the compressor 34 is operated as shown in FIG. The manual operation valve 48 is kept open. At this time, in the cryogenic cooling device 10 </ b> A, the liquid helium 19 in the dewar 42 is supplied to the cooling pipe 13 through the transfer tube 43. The liquid helium 19 supplied from the inlet 13 a of the cooling pipe 13 exchanges heat with the superconducting coil 17 in contact with the cooling pipe 13, and then is discharged to the outside from the outlet 13 b of the cooling pipe 13.

  After the supply of the liquid helium 19 is started, the control unit 16 determines the temperature of the superconducting coil 17 and the temperature of the liquid helium 19 discharged from the cooling pipe 13 from the cooled object temperature measurement unit 14 and the outflow liquid measurement unit 15. taking measurement. The control unit 16 determines the cooling state of the superconducting coil 17 and the state of the liquid helium 19 from the values of the object temperature measurement unit 14 and the outflow liquid measurement unit 15. When the temperature of the superconducting coil 17 is about 4K and the temperature of the liquid helium 19 discharged from the cooling pipe 13 is also about 4K, the liquid helium 19 is discharged from the cooling pipe 13 in a liquid state, and the superconducting coil 17 And the temperature difference between the liquid helium 19 discharged from the cooling pipe 13 is small (for example, 1K or less). In this case, the control unit 16 causes the superconducting coil 17 to be sufficiently cooled to an extremely low temperature (for example, 4K), the liquid helium 19 is released from the superconducting coil 17 into the atmosphere with little heat absorption, and the liquid helium 19 is consumed wastefully. It can be said that. In this case, the control unit 16 sends an instruction to reduce or close the opening of the flow rate adjustment valve V11 to reduce the flow rate of the liquid helium 19 supplied from the dewar 42. The flow control of the liquid helium 19 by the control unit 16 is continuously performed from the start of the supply of the liquid helium 19 until the superconducting coil 17 reaches the target temperature.

  In an example of an operation method for cooling the superconducting coil 17 using the cryogenic cooling device 10A, when the liquid helium 19 is supplied to the cooling pipe 13, the compressor 34 is still in operation. However, the present invention is not limited to this, and the operation of the compressor 34 may be stopped.

  As described above, according to this embodiment, the cryogenic cooling device 10 </ b> A includes the temperature of the superconducting coil 17 and the temperature of the liquid helium 19 discharged from the cooling pipe 13 in the object temperature measuring unit 14 and the outflow liquid measuring unit 15. By detecting the temperature and controlling the flow rate adjusting valve V11 to control the supply amount of the liquid helium 19 supplied to the cooling pipe 13, the consumption amount of the liquid helium 19 can be managed. For this reason, the cryogenic cooling device 10A is liquid helium used for cooling the superconducting coil 17 at the time of pre-cooling at the start of operation of the cryogenic cooling device 10A or when the superconducting coil 17 is cooled at room temperature or after quenching. 19 can be reduced, and the superconducting coil 17 can be efficiently cooled while reducing the amount of liquid helium 19 released to the outside without heat exchange with the superconducting coil 17. According to the cryogenic cooling device 10A, compared to the conventional cooling device, the amount of liquid helium 19 released to the outside without heat exchange can be reduced to, for example, 10% or less, preferably 5% or less. In addition, the amount of liquid helium 19 used can be reduced to about 80%, for example. For this reason, even if it is expected that the amount of liquid helium 19 supplied into the apparatus will increase as the cryogenic cooling device 10A or the superconducting coil 17 becomes larger in the future, the superconducting coil 17 and Therefore, the amount of liquid helium 19 released to the outside without being used for heat exchange can be reduced, and the effect of reducing the amount of liquid helium 19 used can be enhanced.

  Therefore, according to this embodiment, power devices such as generators and power cables, power storage devices, high magnetic field generators such as superconducting magnets, which are small and low power consumption high magnetic field generators, medical MRI, single crystals It can be effectively used for pulling devices, superconducting equipment such as rotating gantry, high magnetic field NMR, magnetic levitation train, magnetic separation device and the like.

  In this embodiment, the case where the combination of the superconducting coil 17 and the heat insulating container 21 is one has been described. However, the combination of the superconducting coil 17 and the heat insulating container 21 may be two or more, and the superconducting coil 17 and the heat insulating container 21 may be insulated. Even when there are a plurality of combinations of containers 21, the temperature of the plurality of superconducting coils 17 is measured, the supply of liquid helium 19 to the cooling pipe 13 connected to each superconducting coil 17 is controlled, and the plurality of systems are controlled simultaneously. May be.

(Second Embodiment)
A cryogenic cooling device according to a second embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member which has the same function as the said embodiment, and detailed description is abbreviate | omitted. In this embodiment, a case where liquid nitrogen is used as the cryogenic liquid will be described. FIG. 4 is a schematic cross-sectional view showing the configuration of the cryogenic cooling device according to the second embodiment. As shown in FIG. 4, the cryogenic cooling device 10 </ b> B includes a cryostat 11, a cryogenic refrigerator 12, a cooling pipe 13, a branch cooling pipe 51, an object temperature measuring unit 14, and a container temperature measuring unit 52. And the control part 16, the flow regulating valves V11 and V12, and the diversion regulating valves V21 and V22.

  In this embodiment, liquid nitrogen 53 is accommodated in the dewar 42, and liquid nitrogen 53 is injected into the cooling pipe 13 from the cryogenic liquid injection part 41.

  The branch cooling pipe 51 branches from the upstream side in the flow direction of the liquid nitrogen 53 to the outside of the heat insulating container 21 of the cooling pipe 13, bypasses the heat insulating container 21, and comes into contact with the outside of the heat insulating container 21. And connected below the heat-insulating container 21 of the cooling pipe 13 in the flow direction of the liquid nitrogen 53. The branch cooling pipe 51 is connected to the cooling pipe 13 via the diversion control valves V21 and V22. Thereby, a part of the liquid nitrogen 53 supplied to the cooling pipe 13 is supplied to the branch cooling pipe 51, and the liquid nitrogen 53 supplied to the branch cooling pipe 51 is branched via the branch cooling pipe 51. After exchanging heat with the heat insulating container 21 in contact with the cooling pipe 51, it merges with the liquid nitrogen 53 in the cooling pipe 13 on the outlet side of the cooling pipe 13, and is discharged to the outside from the outlet 13 b of the cooling pipe 13.

  The diversion regulating valves V21 and V22 are provided in the branch cooling pipe 51 and adjust the flow rate of the liquid nitrogen 53 supplied to the branch cooling pipe 51.

  The to-be-cooled object temperature measuring unit 14 is provided in the superconducting coil 17 and measures the temperature of the superconducting coil 17, and the temperature of the superconducting coil 17 is, for example, about a very low temperature (for example, 4K). Is preferred.

  The container temperature measurement part 52 is provided in the heat insulation container 21, and measures the temperature in the heat insulation container 21, and the temperature in the heat insulation container 21 becomes 20-50K (for example, 40K) inside, for example. It is preferable.

  In addition to each member such as the object to be cooled temperature measurement unit 14, the compressor 34, the flow rate adjustment valves V11 and V12, the inflow liquid sensor 43a, the safety valve 44, the gas exhaust valve 45, and the gas introduction valve 46, the control unit 16 It is connected to each member which comprises cryogenic cooling device 10B, such as container temperature measurement part 52 and flow control valves V21 and V22. The control unit 16 includes a map indicating a relationship between a predetermined temperature as a reference of the heat insulating container 21 measured by the container temperature measuring unit 52, a temperature difference between the object temperature measuring unit 14 and the container temperature measuring unit 52, and the like. You may memorize | store in a memory | storage means beforehand. The control unit 16 determines the cooling state of the superconducting coil 17, the state of the liquid helium 19, the temperature in the heat insulating container 21, and the like based on the measurement results of the object temperature measuring unit 14 and the container temperature measuring unit 52, The opening degree of the flow rate adjusting valves V11 and V12 or the diversion adjusting valves V21 and V22 is adjusted, and the cooling pipe 13 or the branch cooling pipe 51 of the liquid nitrogen 53 according to the state of the liquid nitrogen 53, the temperature in the heat insulating container 21, or the like. The supply amount to is controlled. In this embodiment, the opening degree of the diversion regulating valves V21 and V22 is adjusted depending on whether or not the temperature of the heat insulating container 21 is cooled to about 70 to 100K (for example, 80K).

  Next, an example of a cryogenic cooling method for lowering the temperature in the heat insulating container 21 while cooling the superconducting coil 17 to a cryogenic temperature using the cryogenic cooling device 10B will be described. In FIGS. 5 and 6, the flow control valves V11 and V12 and the diversion control valves V21 and V22 shown in white indicate that the valves are open, and the valves are shown in black. Means that the valve is closed.

  In the cryogenic cooling device 10B, when the cryogenic cooling device 10B is in a normal operation state, such as when the superconducting coil 17 is cooled to a cryogenic temperature, the control unit 16 performs a flow rate as shown in FIG. The control valves V11 and V12 and the flow dividing control valves V21 and V22 are closed, and an instruction to start the operation of the compressor 34 is sent. At this time, in the cryogenic cooling device 10B, like the cryogenic cooling device 10A, the superconducting coil 17 is cooled to about 4K, and the inner space surrounded by the heat insulating container 21 is 20K to 50K (for example, 40K). To a degree.

  At the start of operation of the cryogenic cooling device 10B, or when the superconducting coil 17 is at room temperature or when the temperature of the superconducting coil 17 has risen after being quenched and needs to be cooled to a very low temperature that can be excited, the control unit 16 6 sends an instruction to open the flow rate adjusting valves V11 and V12 while operating the compressor 34, as shown in FIG. The manual operation valve 48 is kept open. At this time, in the cryogenic cooling device 10 </ b> B, the liquid nitrogen 53 in the dewar 42 is supplied to the cooling pipe 13 through the transfer tube 43. The liquid nitrogen 53 supplied to the cooling pipe 13 exchanges heat with the superconducting coil 17 in contact with the cooling pipe 13, and then is discharged to the outside from the outlet of the cooling pipe 13.

  After starting the supply of the liquid nitrogen 53, the control unit 16 measures the temperatures of the superconducting coil 17 and the heat insulating container 21 from the object temperature measuring unit 14 and the container temperature measuring unit 52. The control unit 16 measures the temperature of the heat insulating container 21 from the value of the container temperature measurement unit 52 and measures the temperature of the superconducting coil 17 from the value of the cooled object temperature measurement unit 14.

  Based on the measurement results of the object temperature measurement unit 14 and the container temperature measurement unit 52, the control unit 16 determines that the container temperature measurement unit 52 is equal to or higher than a predetermined temperature (for example, 120 to 300 K), and measures the object temperature to be cooled. When the temperature difference between the unit 14 and the container temperature measuring unit 52 is equal to or greater than a predetermined temperature difference (for example, 20K), the controller 16 determines that the temperature of the heat insulating container 21 is 70 to 100K (for example, 80K). Since it is not cooled to such a degree, it is determined that the inner space surrounded by the heat insulating container 21 is not maintained at about 70 to 100K (for example, 80K). Therefore, the control unit 16 performs heat exchange between the space between the superconducting coil 17 and the heat insulating container 21 and the superconducting coil 17 passing through the cooling pipe 13, thereby increasing the temperature of the liquid nitrogen 53. Regardless of whether or not the superconducting coil 17 is cooled to a very low temperature, the cooling efficiency of the liquid nitrogen 53 with respect to the superconducting coil 17 is reduced, so that the liquid nitrogen 53 does not sufficiently absorb heat from the superconducting coil 17 and enters the atmosphere. It is determined that there is a possibility that the liquid nitrogen 53 is discharged and is wasted. In this case, as shown in FIG. 4, the control unit 16 further sends a signal for opening the diversion regulating valves V <b> 21 and V <b> 22 to supply at least a part of the liquid nitrogen 53 supplied to the cooling pipe 13 to the branch cooling pipe 51. . The liquid nitrogen 53 supplied to the branch cooling pipe 51 is subjected to heat exchange with the heat insulating container 21 in contact with the branch cooling pipe 51 via the branch cooling pipe 51, and after cooling the heat insulating container 21, It merges with the liquid nitrogen 53 in the cooling pipe 13 on the outlet side, and is discharged to the outside from the outlet 13 b of the cooling pipe 13. Control of the flow rate of the liquid nitrogen 53 to the cooling pipe 13 and the branch cooling pipe 51 is continuously performed from the start of supply of the liquid nitrogen 53 until the superconducting coil 17 and the heat insulating container 21 reach predetermined temperatures.

  In this embodiment, the liquid nitrogen 53 is supplied to the cooling pipe 13 and the branch cooling pipe 51, but the liquid nitrogen 53 may be supplied only to the cooling pipe 13 or the branch cooling pipe 51.

  Therefore, according to the present embodiment, the temperature of the superconducting coil 17 and the heat insulating container 21 is measured by the to-be-cooled object temperature measuring unit 14 and the container temperature measuring unit 52 to control the diversion regulating valves V21 and V22 of the cooling pipe 13. As a result, the cryogenic cooling device 10B discharges to the outside without exchanging heat with the superconducting coil 17, such as during pre-cooling at the start of operation of the cryogenic cooling device 10B or when the superconducting coil 17 is cooled at room temperature or after quenching. The space in the superconducting coil 17 and the heat insulating container 21 can be efficiently cooled while reducing the amount of the liquid nitrogen 53.

  In the present embodiment, the case where one superconducting coil 17 is provided has been described, but a plurality of superconducting coils 17 may be provided. Further, the case where one main cooling system A and one sub cooling system B are provided has been described, but when a plurality of superconducting coils 17 are provided, the main cooling system A and the sub cooling system B are provided for each superconducting coil 17. A plurality of main cooling systems A and sub cooling systems B may be provided according to the number of superconducting coils 17. For example, when three superconducting coils 17 are accommodated in the vacuum vessel 22, the cryogenic cooling device 10B includes three cryogenic refrigerators 12 as the main cooling system A, and the cooling pipe 13, The to-be-cooled object temperature measuring unit 14, the effluent liquid measuring unit 15, and the three flow rate adjusting valves V <b> 11 and V <b> 12 are provided, and the cryogenic refrigerator 12, the cooling pipe 13, and the to-be-cooled object temperature measuring unit 14, an effluent liquid measurement unit 15, and flow rate adjustment valves V11 and V12 are provided.

  In this embodiment, the case where liquid nitrogen 53 is used as the cryogenic liquid has been described. However, liquid helium 19 may be used as in the first embodiment. Further, both liquid helium 19 and liquid nitrogen 53 may be used.

(Third embodiment)
A cryogenic cooling device according to a third embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member which has the same function as the said embodiment, and detailed description is abbreviate | omitted. In the present embodiment, a case where liquid nitrogen is used as the cryogenic liquid will be described, as in the first embodiment. FIG. 7 is a schematic cross-sectional view showing the configuration of the cryogenic cooling device according to the third embodiment. As shown in FIG. 7, the cryogenic cooling device 10 </ b> C has a configuration of the cryogenic cooling device 10 </ b> A of the first embodiment shown in FIG. 1 and the cryogenic cooling device 10 </ b> B of the second embodiment shown in FIG. 4. It is a combination. That is, the cryogenic cooling device 10C according to the present embodiment includes a cryostat 11, a cryogenic refrigerator 12, a cooling pipe 13, a to-be-cooled object temperature measuring unit 14, an effluent liquid measuring unit 15, a control unit 16, It has the branch cooling pipe 51, the container temperature measurement part 52, the flow regulating valves V11 and V12, and the diversion regulating valves V21 and V22.

  The control unit 16 includes an object temperature measurement unit 14, an outflow liquid measurement unit 15, a compressor 34, a container temperature measurement unit 52, flow rate adjustment valves V11 and V12, an inflow liquid sensor 43a, a safety valve 44, a gas exhaust valve 45, and a gas. The inlet valve 46, the helium gas cylinder 47, and the manual operation valve 48 are connected to each member constituting the cryogenic cooling device 10C.

  This embodiment is a combination of the first embodiment and the second embodiment, and a cryogenic cooling method for cooling the superconducting coil 17 to a cryogenic temperature, for example, about 4K, using the cryogenic cooling device 10C. Since this is performed in the same manner as in the first embodiment and the second embodiment, description thereof is omitted in this embodiment.

  Therefore, according to this embodiment, the cryogenic cooling device 10 </ b> C controls the flow rate adjustment valve V <b> 11 based on the measurement results of the cooled object temperature measurement unit 14 and the effluent liquid measurement unit 15 and is supplied to the cooling pipe 13. The supply amount of liquid helium 19 is controlled, and at the same time, the flow control valves V21 and V22 are controlled based on the measurement results of the object temperature measurement unit 14 and the container temperature measurement unit 52, and supplied to the cooling pipe 13. By controlling the amount of liquid helium 19 supplied, the space in the superconducting coil 17 and the heat insulating container 21 can be cooled more efficiently. Thereby, the cryogenic cooling device 10C can cool the superconducting coil 17 more efficiently in the case of pre-cooling at the start of operation of the cryogenic cooling device 10C or when the superconducting coil 17 is cooled at room temperature or after quenching. it can.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various combinations, omissions, replacements, changes, and the like can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10A to 10C Cryogenic cooling device 11 Cryostat 12 Cryogenic refrigerator 13 Cooling pipe 14 Cooled object temperature measuring part 15 Outflow liquid measuring part 16 Control part 17 Superconducting coil (cooled object)
18 Refrigerant gas 19 Liquid helium (cryogenic liquid)
21 Insulating container 22 Vacuum container 31 First cooling stage 32 Second cooling stage 34 Compressor
35 Supply piping 41 Cryogenic liquid injection part 42 Dewar 43 Transfer tube 43a Inflow liquid sensor 44 Safety valve 45 Gas exhaust valve 46 Gas introduction valve 47 Helium gas cylinder 48 Manual operation valve 49 Guide pipe 50A, 50B Connecting part 51 Branch cooling pipe 52 Container temperature Measuring unit 53 Liquid nitrogen (cryogenic liquid)
A Main cooling system B Sub cooling system V11, V12 Flow rate adjustment valve V13 Gas supply valve V21, V22 Split flow adjustment valve

Claims (10)

A cryostat comprising a heat insulating container for containing an object to be cooled, and a vacuum container containing the heat insulating container inside;
A main cooling system that cools the object to be cooled with refrigerant gas using a cryogenic refrigerator;
A sub-cooling system that cools the object to be cooled using a cryogenic liquid;
A control unit for controlling the supply amount of the refrigerant gas and the cryogenic liquid;
A cryogenic cooling device comprising:
The sub-cooling system is
A cooling pipe provided in contact with the outside of the object to be cooled, through which the cryogenic liquid passes;
A cooled object temperature measuring unit for measuring the temperature of the cooled object, which is provided in contact with the outside of the cooled object;
An effluent liquid measuring unit for measuring the temperature of the cryogenic liquid provided on the discharge side of the cryogenic liquid from a portion in contact with the object to be cooled of the cooling pipe;
A flow rate adjustment valve that adjusts the supply amount of the cryogenic liquid supplied to the portion in contact with the object to be cooled;
Comprising
The controller adjusts the opening of the flow rate adjustment valve based on the measurement results of the object temperature measuring unit and the effluent liquid measuring unit, and the supply amount of the cryogenic liquid to the cooling pipe is controlled. A cryogenic cooling device characterized by the above. A cryostat comprising a heat insulating container surrounding the object to be cooled; and a vacuum container containing the heat insulating container inside;
A main cooling system that cools the object to be cooled with refrigerant gas using a cryogenic refrigerator;
A sub-cooling system that cools the object to be cooled using a cryogenic liquid;
A control unit for controlling the supply amount of the refrigerant gas and the cryogenic liquid;
A cryogenic cooling device comprising:
The sub-cooling system is
A cooling pipe provided in contact with the outside of the object to be cooled, through which the cryogenic liquid passes;
The cryogenic liquid that is supplied to the object to be cooled is provided so as to be branched from the cooling pipe through which the cryogenic liquid passes, and to contact the outside of the heat insulating container, and the cryogenic liquid that has exchanged heat with the object to be cooled passes through. A branch cooling pipe connected to the cooling pipe;
A cooled object temperature measuring unit for measuring the temperature of the cooled object, which is provided in contact with the outside of the cooled object;
A container temperature measurement unit for measuring the temperature in the heat insulation container, provided to be in contact with the outside of the heat insulation container;
A flow rate adjustment valve that adjusts the supply amount of the cryogenic liquid supplied to the portion in contact with the object to be cooled;
A shunt adjusting valve provided in the cooling pipe for adjusting a flow rate of the cryogenic liquid supplied to the branch cooling pipe;
Based on the measurement results of the container temperature measurement unit and the cooled object temperature measurement unit, a control unit that controls the flow rate adjustment valve or the diversion adjustment valve;
Comprising
The control unit adjusts an opening degree of a flow rate adjustment valve or a diversion control valve based on a measurement result of the object to be cooled temperature measurement unit or the container temperature measurement unit, and supplies the pole to the cooling pipe or the branch cooling pipe. A cryogenic cooling device, wherein a supply amount of a cryogenic liquid is controlled. The sub-cooling system is provided so as to be branched from the cooling pipe through which the cryogenic liquid supplied to the object to be cooled passes and is in contact with the outside of the heat insulating container, and the heat exchange with the object to be cooled is performed. A branch cooling pipe connected to the cooling pipe through which the cryogenic liquid passes;
A container temperature measurement unit for measuring the temperature in the heat insulation container, provided to be in contact with the outside of the heat insulation container;
A shunt adjusting valve provided in the cooling pipe for adjusting a flow rate of the cryogenic liquid supplied to the branch cooling pipe;
Further comprising
The control unit adjusts an opening degree of the flow rate adjustment valve or the diversion control valve based on the measurement results of the container temperature measurement unit and the cooled object temperature measurement unit, and supplies the cooling pipe or the branch cooling pipe. The cryogenic cooling device according to claim 1, wherein a supply amount of the cryogenic liquid is controlled.   The cryogenic cooling device according to claim 2 or 3, wherein a plurality of the main cooling system and the sub cooling system are provided according to the number of the objects to be cooled. The main cooling system comprises a compressor that compresses the refrigerant gas after cooling the object to be cooled,
The cryogenic cooling device according to any one of claims 1 to 4, wherein the refrigerant gas compressed by the compressor is supplied to the cryogenic refrigerator.   The cryogenic cooling device according to any one of claims 1 to 5, wherein the object to be cooled is a superconducting coil or a superconducting element.   The cryogenic cooling device according to any one of claims 1 to 6, wherein the cryogenic liquid is liquid nitrogen or liquid helium. A cryostat comprising a heat-insulating container surrounding the object to be cooled, a vacuum container containing the heat-insulating container, and a main cooling system for cooling the object to be cooled with refrigerant gas using a cryogenic refrigerator And a subcooling system that cools the object to be cooled using a cryogenic liquid that passes through a cooling pipe provided in contact with the outside of the object to be cooled. ,
Supplying the cryogenic liquid to the cooling pipe, and cooling the object to be cooled with the cryogenic liquid;
Measuring the temperature of the object to be cooled and measuring the temperature of the cryogenic liquid discharged from the cryostat;
Including
The supply amount of the cryogenic liquid to the cooling pipe is controlled based on the measurement result of the temperature of the object to be cooled and the temperature of the cryogenic liquid discharged from the cryostat. Low temperature cooling method. A cryostat comprising a heat-insulating container surrounding the object to be cooled, a vacuum container containing the heat-insulating container, and a main cooling system for cooling the object to be cooled with refrigerant gas using a cryogenic refrigerator And a subcooling system that cools the object to be cooled using a cryogenic liquid that passes through a cooling pipe provided in contact with the outside of the object to be cooled. ,
The pole that is provided so as to be branched from the cooling pipe or the cooling pipe through which the cryogenic liquid supplied to the object to be cooled passes and is in contact with the outside of the heat insulating container, and exchanges heat with the object to be cooled. Supplying the cryogenic liquid to a branch cooling pipe connected to the cooling pipe through which the cryogenic liquid passes, and cooling the object to be cooled or the heat insulating container with the cryogenic liquid;
Measuring the temperature of the object to be cooled or the insulated container;
Including
A cryogenic cooling method, comprising: controlling a supply amount of the cryogenic liquid to the cooling pipe or the branch cooling pipe based on a temperature result of the object to be cooled or the heat insulating container. While being supplied with the cryogenic liquid to the cooling pipe, the cryogenic liquid supplied to the object to be cooled is branched from the cooling pipe through which the cryogenic liquid passes and is in contact with the outside of the heat insulating container. Supplying the cryogenic liquid to a branch cooling pipe connected to the cooling pipe through which the cryogenic liquid heat-exchanged with an object passes, and cooling the object to be cooled or the heat insulating container with the cryogenic liquid;
Measuring the temperature of the insulated container or the object to be cooled;
Further including
The cryogenic cooling method according to claim 8, wherein a supply amount of the cryogenic liquid to the cooling pipe or the branch cooling pipe is controlled based on a temperature result of the object to be cooled or the heat insulating container.

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