JP2018085445A - Superconducting magnet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconducting magnet device capable of raising a temperature of a refrigerator while suppressing a temperature rise of a superconducting coil during maintenance of a refrigerator.SOLUTION: A superconducting magnet device (1) includes a superconducting coil (10), a vacuum vessel (14), a refrigerator (20) detachably attached to the vacuum vessel (14), a working medium flow path (30) including refrigerator heat exchange units (31 and 32) that are thermally brought into contact with the refrigerator (20) and a coil heat exchange unit (33) that are thermally brought into contact with the superconducting coil (10), and a coil avoidance flow path (56) used to lead out a gaseous working medium from a portion among the refrigerator heat exchange units(31 and 32) and the coil heat exchange unit (33) of the working medium flow path (30) to the outside of the vacuum vessel (14).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a superconducting magnet device.

  2. Description of the Related Art Conventionally, there is known a superconducting magnet device capable of bringing a superconducting coil into a superconducting state by cooling the superconducting coil with a refrigerator through a gas phase working medium (helium gas or the like). For example, Patent Document 1 discloses a superconducting coil, a vacuum container that accommodates the superconducting coil, a GM refrigerator attached to the vacuum container, and a gas phase working medium (gas) that is disposed outside the vacuum container. A superconducting magnet device is disclosed that includes a gas circulation compressor that performs gas circulation and a first pipe that circulates gas. The first pipe is in thermal contact with each of the GM refrigerator and the superconducting coil.

  In this superconducting magnet device, the superconducting coil is maintained in a superconducting state by circulating a gas phase working medium in the first pipe. Specifically, the superconducting coil is cooled by the working medium cooled by the refrigerator. The working medium after cooling the superconducting coil flows into the gas circulation compressor disposed outside the vacuum vessel through the first pipe.

JP2015-12193A

  When maintenance of a refrigerator is performed in a superconducting magnet device as described in Patent Document 1, first, an operation of raising the temperature of the refrigerator to about room temperature is often performed. This is because if the refrigerator is removed from the vacuum vessel without the operation being performed, there is a risk that problems such as solidification of moisture in the air may occur in the refrigerator. For this reason, at the time of maintenance of a refrigerator, the said operation is first performed, and after that, the refrigerator is removed from the vacuum vessel and the maintenance of the refrigerator is performed.

  For example, when the temperature of the refrigerator is raised in the superconducting magnet device, it is conceivable that the gas circulation compressor is continuously driven while the refrigerator is stopped. If it does in this way, since the working medium of about normal temperature will continue to be supplied in the 1st piping toward the refrigerator from a gas circulation compressor, the refrigerator will heat up. However, when this operation is performed, since the working medium after heating the refrigerator heats the superconducting coil, the temperature of the superconducting coil also rises. When the temperature of the superconducting coil rises, after the maintenance of the refrigerator, the precooling time required for cooling the superconducting coil becomes longer until the superconducting coil is in a superconducting state.

  An object of the present invention is to provide a superconducting magnet device capable of increasing the temperature of the refrigerator while suppressing the temperature increase of the superconducting coil during maintenance of the refrigerator.

  As means for solving the above-mentioned problems, the present invention provides a superconducting coil, a vacuum container that accommodates the superconducting coil, a refrigerator that can be detachably attached to the vacuum container, and a thermal apparatus for the refrigerator. A working medium for flowing a gas phase working medium in the order of the refrigerator heat exchanging part and the coil heat exchanging part, including a refrigerator heat exchanging part in contact with the coil and a coil heat exchanging part in thermal contact with the superconducting coil A coil avoidance flow path for deriving the gas phase working medium out of the vacuum vessel from a portion of the working medium flow path between the refrigerator heat exchange section and the coil heat exchange section. A superconducting magnet device is provided.

  This superconducting magnet device is a coil avoidance flow in which a gas phase working medium (helium gas, etc.) heat-exchanged with a refrigerator in the refrigerator heat exchange section is led out of the vacuum vessel without passing through the coil heat exchange section. Has a road. For this reason, during maintenance of the refrigerator, the working medium is supplied to the working medium flow path with the refrigerator stopped, and the working medium after heating the refrigerator is removed from the vacuum vessel through the coil avoidance flow path. Thus, it is avoided that the working medium that has heated the refrigerator in the refrigerator heat exchange section also heats the superconducting coil in the coil heat exchange section. Therefore, it is possible to quickly raise the temperature of the refrigerator while maintaining the temperature of the superconducting coil at a low temperature. Therefore, after the maintenance of the refrigerator, the time required for precooling the superconducting coil is shortened until the superconducting coil is in a superconducting state.

  In this case, it is preferable that the apparatus further includes a pump that is disposed outside the vacuum vessel and that sends the gas phase working medium flowing out of the vacuum vessel through the working medium flow path to the refrigerator heat exchange unit.

  In this way, since the gas phase working medium circulates through the refrigerator heat exchanging section, the coil heat exchanging section, and the pump, the amount of working medium necessary for cooling the superconducting coil is reduced.

  Furthermore, in this case, the downstream end of the coil avoidance flow path is connected to a portion of the working medium flow path outside the vacuum vessel and upstream of the pump, and the coil avoidance flow path Preferably has a heating unit for heating the working medium outside the vacuum vessel.

  In this way, the working medium that has flowed out of the vacuum vessel through the coil avoidance flow path can be returned to the working medium flow path, and since the working medium is heated by the heating unit, the load on the pump is reduced. Reduced.

  Further, in the superconducting magnet device, in the steady operation in which the refrigerator is driven and the gas phase working medium flows in the order of the refrigerator heat exchanger and the coil heat exchanger, maintenance of the refrigerator is performed. When the signal indicating that the operation is performed is stopped, the refrigerator is stopped, and from the steady operation, the refrigerator rises in which the gas phase working medium flows in the order of the refrigerator heat exchange unit and the coil avoidance flow path. It is preferable to further include a switching unit for switching to the temperature operation.

  If it does in this way, for example, an operator will perform operation which transmits the said signal toward a switching part, and it switches from steady operation to refrigerator temperature rising operation. Therefore, it becomes easy to perform maintenance of the refrigerator.

  As described above, according to the present invention, it is possible to provide a superconducting magnet device capable of increasing the temperature of the refrigerator while suppressing the temperature increase of the superconducting coil during maintenance of the refrigerator.

It is sectional drawing which shows the outline of the superconducting magnet apparatus of one Embodiment of this invention. It is a figure which shows the flow of the working medium at the time of the steady operation of the superconducting magnet apparatus shown in FIG. It is a figure which shows the flow of the working medium at the time of the precooling driving | operation of the superconducting magnet apparatus shown in FIG. It is a figure which shows the flow of the working medium at the time of the refrigerator temperature rising operation of the superconducting magnet apparatus shown in FIG.

  A superconducting magnet apparatus according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a superconducting magnet device 1 includes a superconducting coil 10, a radiation shield 12, a vacuum vessel 14, a refrigerator 20, a working medium flow path 30, a pump 40, and a first heat exchanger. 41, the 2nd heat exchanger 42, the heat exchanger avoidance flow path 54, the coil avoidance flow path 56, and the switching part 60 are provided.

  The superconducting coil 10 is a coil obtained by winding a wire made of a superconductor (superconducting substance) around a winding frame.

  The radiation shield 12 has a shape that accommodates the superconducting coil 10. The radiation shield 12 is made of aluminum.

  The vacuum vessel 14 has a shape that accommodates the radiation shield 12. The inside of the vacuum vessel 14 is kept in a vacuum. Thereby, the penetration | invasion of the heat | fever into the vacuum vessel 14 is suppressed. The vacuum vessel 14 is made of stainless steel.

  The refrigerator 20 cools the superconducting coil 10 through a gas phase working medium. The refrigerator 20 includes a first cooling stage 21, a second cooling stage 22, and an attachment part 23.

  The first cooling stage 21 is thermally connected to the radiation shield 12. The first cooling stage 21 can reach the first lowest temperature (about 40K to 70K).

  The second cooling stage 22 is located in the radiation shield 12. The second cooling stage 22 can reach a second lowest temperature (about 4K) that is lower than the first lowest temperature.

  The attachment portion 23 can be detachably attached to the vacuum vessel 14 in a state where the first cooling stage 21 and the second cooling stage 22 are located in the vacuum vessel 14.

  The working medium flow path 30 is a flow path for flowing a gaseous working medium (such as helium gas or hydrogen gas). In the present embodiment, the working medium flow path 30 has a shape in which a gas phase working medium is circulated inside and outside the vacuum container 14. The working medium flow path 30 includes a first heat exchange part 31, a second heat exchange part 32, and a third heat exchange part 33. The first heat exchange unit 31 is in thermal contact with the first cooling stage 21. The second heat exchange unit 32 is in thermal contact with the second cooling stage 22. The third heat exchange unit 33 is in thermal contact with the superconducting coil 10. That is, the first heat exchange unit 31 and the second heat exchange unit 32 constitute a “refrigerant heat exchange unit” that is in thermal contact with the refrigerator 20, and the third heat exchange unit 33 heats the superconducting coil 10. A “coil heat exchanging section” that makes contact with each other. In the present embodiment, helium gas is used as a gas phase working medium.

  A pump 40 that sends helium gas that has flowed out of the vacuum container 14 through the working medium flow path 30 toward the first heat exchange unit 31 is provided in a portion of the working medium flow path 30 outside the vacuum container 14. A first on-off valve V1, a first flow rate sensor F1, and a safety valve RV capable of opening adjustment are provided in a portion of the working medium flow path 30 outside the vacuum vessel 14 and downstream of the pump 40. ing. A second opening / closing valve V2 capable of adjusting the opening degree and a second flow rate sensor F2 are provided outside the vacuum vessel 14 and upstream of the pump 40 in the working medium flow path 30.

  The first heat exchanger 41 is provided in the radiation shield 12. The first heat exchanger 41 includes the helium gas after being cooled by the first cooling stage 21 in the first heat exchanging unit 31 and before being cooled by the second cooling stage 22 in the second heat exchanging unit 32, 3. Heat exchange is performed with the helium gas after the superconducting coil 10 is cooled by the heat exchange unit 33.

  The second heat exchanger 42 is provided inside the vacuum vessel 14 and outside the radiation shield 12. The second heat exchanger 42 exchanges heat between the helium gas before flowing into the first heat exchange unit 31 and the helium gas after passing through the first heat exchanger 41.

  In the present embodiment, a cooling flow path 52 for cooling the radiation shield 12 is provided. The cooling flow path 52 is connected to the working medium flow path 30. Specifically, the upstream end of the cooling flow path 52 is connected to a portion of the working medium flow path 30 downstream of the first heat exchange section 31 and upstream of the first heat exchanger 41. . The downstream end of the cooling flow path 52 is connected to a portion of the working medium flow path 30 outside the vacuum vessel 14 and upstream of the pump 40. The cooling channel 52 has a cooling unit 53 that is in thermal contact with the radiation shield 12. For this reason, the radiation shield 12 is cooled by receiving the cold heat that the helium gas received from the first cooling stage 21 in the first heat exchange unit 31 from the helium gas in the cooling unit 53. The cooling flow path 52 is passed through the second heat exchanger 42. For this reason, the helium gas traveling from the outside of the vacuum vessel 14 to the first heat exchange unit 31 through the working medium flow channel 30 is cooled by the helium gas flowing through the cooling flow channel 52 in the second heat exchanger 42. A third opening / closing valve V3 capable of opening adjustment and a third flow rate sensor F3 are provided in a portion of the cooling flow path 52 outside the vacuum vessel 14. Therefore, the flow rate of the helium gas flowing through the cooling flow path 52 is based on the detection values of the first flow rate sensor F1 to the third flow rate sensor F3, respectively of the first on-off valve V1, the second on-off valve V2, and the third on-off valve V3. It is adjusted by adjusting the opening degree.

  The heat exchanger avoidance flow path 54 is a flow path used when the superconducting coil 10 is pre-cooled. The heat exchanger avoidance flow path 54 is a flow path that causes the helium gas that has passed through the third heat exchange section 33 to avoid the heat exchangers 41 and 42. Specifically, the heat exchanger avoidance flow path 54 is for leading out helium gas out of the vacuum vessel 14 from a portion of the working medium flow path 30 between the third heat exchange unit 33 and the first heat exchanger 41. The flow path. The upstream end portion of the heat exchanger avoidance flow path 54 is connected to a portion of the working medium flow path 30 that is downstream of the third heat exchange section 33 and upstream of the first heat exchanger 41. The downstream end of the heat exchanger avoidance flow path 54 is connected to a portion of the working medium flow path 30 outside the vacuum vessel 14 and upstream of the pump 40. The heat exchanger avoidance flow path 54 includes a heating unit 55 that heats the helium gas outside the vacuum vessel 14. A fourth on-off valve V4 and a fourth flow rate sensor F4 capable of adjusting the opening degree are provided outside the vacuum vessel 14 and downstream of the heating unit 55 in the heat exchanger avoidance flow path 54. Yes.

  The coil avoidance flow path 56 is a flow path used when maintenance of the refrigerator 20 is performed. The coil avoidance flow path 56 is a flow path that causes the helium gas that has passed through the second heat exchange section 32 to avoid the third heat exchange section 33. Specifically, the coil avoidance flow path 56 is a flow for deriving helium gas out of the vacuum vessel 14 from a portion of the working medium flow path 30 between the second heat exchange section 32 and the third heat exchange section 33. Road. The upstream end of the coil avoidance flow path 56 is connected to a portion of the working medium flow path 30 between the second heat exchange unit 32 and the third heat exchange unit 33. The downstream end of the coil avoidance flow path 56 is connected to a portion of the working medium flow path 30 outside the vacuum vessel 14 and upstream of the pump 40. The coil avoidance flow path 56 includes a heating unit 57 that heats helium gas outside the vacuum vessel 14. A fifth on-off valve V5 and a fifth flow rate sensor F5 capable of opening adjustment are provided outside the vacuum vessel 14 and downstream of the heating unit 57 in the coil avoidance flow path 56.

  Here, the operation | movement at the time of steady operation of the superconducting magnet apparatus 1 demonstrated above is demonstrated. In the steady operation, the first on-off valve V1, the second on-off valve V2, and the third on-off valve V3 are opened, the fourth on-off valve V4 and the fifth on-off valve V5 are closed, the superconducting coil 10 is energized, and the refrigerator 20 And the pump 40 is driven. In this steady operation, as shown in FIG. 2, a part of the helium gas discharged from the pump 40 circulates in the working medium flow path 30, and the remainder of the helium gas discharged from the pump 40 is a cooling flow path. The working medium flow path 30 is circulated through 52. That is, part of the helium gas is a second heat exchanger 42, a first heat exchange unit 31, a first heat exchanger 41, a second heat exchange unit 32, a third heat exchange unit 33, and a first heat exchanger. 41 and the second heat exchanger 42 flow in this order, and the remaining portion of the helium gas flows through the second heat exchanger 42, the first heat exchange unit 31, the cooling unit 53, and the second heat exchanger 42 in this order.

  A part of the helium gas receives cold heat from the first cooling stage 21 in the first heat exchanging part 31, and then receives further cold heat from the second cooling stage 22 in the second heat exchanging part 32, and converts the cold heat into the third heat. The heat exchange unit 33 gives the superconducting coil 10. Thereby, the superconducting coil 10 is cooled. In this way, the superconducting coil 10 is maintained in a superconducting state. The helium gas after passing through the third heat exchange unit 33 is heated by the helium gas toward the third heat exchange unit 33 in the first heat exchanger 41 and the second heat exchanger 42. Thereby, the temperature of the helium gas after passing through the second heat exchanger 42 becomes a temperature (for example, about room temperature) at which the pump 40 can be stably driven. Therefore, the drive of the pump 40 is stabilized.

  The remaining portion of the helium gas receives cold heat from the first cooling stage 21 in the first heat exchanging section 31 and then applies the cold heat to the radiation shield 12 in the cooling section 53. Thereby, the radiation shield 12 is cooled. Therefore, the radiation shield 12 is cooled more effectively than when the radiation shield 12 is cooled only by the first cooling stage 21. The helium gas that has passed through the cooling unit 53 is heated by the second heat exchanger 42 by the helium gas that travels toward the first heat exchange unit 31. Thereby, the temperature of the helium gas after passing through the second heat exchanger 42 becomes a temperature (for example, about room temperature) at which the pump 40 can be stably driven.

  In this steady operation, as described above, the flow rate of the helium gas flowing through the cooling flow path 52 is determined based on the detection values of the first flow rate sensor F1 to the third flow rate sensor F3. It adjusts by adjusting each opening degree of V2 and the 3rd on-off valve V3.

  Next, the switching unit 60 will be described. The switching unit 60 performs an operation for switching from the pre-cooling operation to the steady operation and an operation for switching from the steady operation to the refrigerator temperature raising operation. The pre-cooling operation is an operation for cooling the superconducting coil 10 from, for example, room temperature so that the superconducting coil 10 is in a superconducting state. The refrigerator temperature raising operation is an operation for raising the temperature of the refrigerator 20 when the refrigerator 20 is maintained.

  First, the pre-cooling operation will be described. In the pre-cooling operation, the first on-off valve V1, the third on-off valve V3, and the fourth on-off valve V4 are opened, the second on-off valve V2 and the fifth on-off valve V5 are closed, and the refrigerator 20 and the pump 40 are driven. . In this pre-cooling operation, as shown in FIG. 3, part of the helium gas discharged from the pump 40 circulates in the working medium flow path 30 via the heat exchanger avoidance flow path 54 and is discharged from the pump 40. The remaining helium gas circulates in the working medium flow path 30 via the cooling flow path 52. That is, a part of the helium gas is supplied to the second heat exchanger 42, the first heat exchange unit 31, the first heat exchanger 41, the second heat exchange unit 32, the third heat exchange unit 33, and the heating unit 55. The remaining helium gas flows through the second heat exchanger 42, the first heat exchange unit 31, the cooling unit 53, and the second heat exchanger 42 in this order.

  A part of the helium gas receives cold heat from the first cooling stage 21 in the first heat exchanging part 31, and then receives further cold heat from the second cooling stage 22 in the second heat exchanging part 32, and converts the cold heat into the third heat. The heat exchange unit 33 gives the superconducting coil 10. Thereby, the superconducting coil 10 is cooled. In this pre-cooling operation, unlike the steady operation, the helium gas after passing through the third heat exchanging portion 33 avoids the first heat exchanger 41 and the second heat exchanger 42 and passes through the heat exchanger avoidance flow path 54. Return to pump 40. For this reason, it is avoided that the helium gas which goes to the 2nd heat exchange part 32 from the 1st heat exchange part 31 is heated with the helium gas which passed the 3rd heat exchange part 33 in the 1st heat exchanger 41. In other words, it is avoided that helium gas is lost before the cold heat received from the first cooling stage 21 is applied to the superconducting coil 10. Therefore, since the cooling heat obtained from each of the cooling stages 21 and 22 is effectively given to the superconducting coil 10, the precooling time of the superconducting coil 10 is shortened.

  The helium gas that has flowed into the heat exchanger avoidance flow path 54 is heated by the heating unit 55. Thereby, the temperature of the helium gas after passing through the heating unit 55 becomes a temperature at which the pump 40 can be stably driven (for example, about room temperature).

  In this precooling operation, the volume of helium gas decreases as the superconducting coil 10 is cooled. When the pressure of the working medium flow path 30 falls below the threshold value, helium enters the working medium flow path 30 from the storage container 71 storing helium gas through the replenishment flow path 72 until the pressure of the working medium flow path 30 becomes equal to or higher than the threshold value. Gas is replenished. Note that the pressure of the working medium flow path 30 is detected by a pressure sensor 73 provided in a portion of the working medium flow path 30 on the upstream side of the pump 40. Replenishment of the working medium flow path 30 with helium gas may be performed manually based on the detection value of the pressure sensor 73, or when a pressure regulator is attached to the storage container 71, it is performed by the pressure regulator. May be.

  When the precooling operation is completed, that is, when the temperature of the superconducting coil 10 reaches the reference value (critical temperature), the switching unit 60 performs the first heat exchange after passing through the third heat exchange unit 33 from the precooling operation to the steady operation. The operation of switching to helium gas returning to the pump 40 via the vessel 41 and the second heat exchanger 42 is performed. Specifically, when the temperature of the superconducting coil 10 reaches a reference value, the switching unit 60 closes the fourth on-off valve V4 and opens the third on-off valve V3 to energize the superconducting coil 10. Note that the temperature of the superconducting coil 10 is detected by a temperature sensor 63 provided in the superconducting coil 10.

  Next, the refrigerator temperature raising operation will be described. This refrigerator temperature raising operation is performed during maintenance of the refrigerator 20. In the refrigerator temperature raising operation, the first on-off valve V1 and the fifth on-off valve V5 are opened, the second on-off valve V2, the third on-off valve V3 and the fourth on-off valve V4 are closed, the pump 40 is driven, and the refrigeration is performed. The machine 20 is stopped. In the refrigerator temperature raising operation, as shown in FIG. 4, the helium gas discharged from the pump 40 circulates through the working medium flow path 30 via the coil avoidance flow path 56. That is, helium gas flows through the second heat exchanger 42, the first heat exchange unit 31, the first heat exchanger 41, the second heat exchange unit 32, and the heating unit 57 in this order. At this time, helium gas having a room temperature flowing into the vacuum vessel 14 heats the first cooling stage 21 in the first heat exchange unit 31 and then heats the second cooling stage 22 in the second heat exchange unit 32. . Therefore, the refrigerator 20 is quickly heated. In the refrigerator temperature increasing operation, since the refrigerator 20 is stopped, the temperature of the helium gas that has passed through the second heat exchange unit 32 is higher than the critical temperature of the superconducting coil 10, but the helium gas is Then, it flows into the coil avoidance flow path 56 without passing through the third heat exchange part 33 that is in thermal contact with the superconducting coil 10. For this reason, the heating of the superconducting coil 10 by the helium gas which heated the refrigerator 20 is avoided. That is, in the refrigerator temperature increasing operation of the present embodiment, the temperature of the refrigerator 20 quickly increases while the temperature increase of the superconducting coil 10 is suppressed.

  The refrigerator temperature rising operation described above is started when the switching unit 60 receives a signal indicating that maintenance of the refrigerator 20 is performed during steady operation. That is, when receiving the signal during steady operation, the switching unit 60 closes the second on-off valve V2 and the third on-off valve V3, opens the fifth on-off valve V5, and stops the refrigerator 20. The signal is transmitted to the switching unit 60 by, for example, a switch operation by an operator.

  When the temperature of each of the cooling stages 21 and 22 becomes about room temperature by the refrigerator temperature increasing operation, the refrigerator 20 is removed from the vacuum vessel 14 and the maintenance of the refrigerator 20 is performed. The temperature of the first cooling stage 21 is detected by a temperature sensor 61 provided on the first cooling stage 21, and the temperature of the second cooling stage 22 is detected by a temperature sensor 62 provided on the second cooling stage 22. Is done.

  During the maintenance of the refrigerator 20, the drive of the pump 40 is continued. Thereby, since the site | part (cylinder etc.) which hold | maintains the refrigerator 20 in the vacuum vessel 14 continues being heated by helium gas, the adhesion of the frost etc. to the said site | part are suppressed. After the maintenance of the refrigerator 20 is completed, the refrigerator 20 is attached to the vacuum container 14. Then, the refrigerator 20 is driven, the fifth on-off valve V5 is closed, and the second on-off valve V2 and the third on-off valve V3 are opened. As a result, the radiation shield 12 and the superconducting coil 10 that have naturally increased in temperature during the maintenance of the refrigerator 20 are gradually cooled. Thereafter, the superconducting magnet device 1 returns to the steady operation.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, the switching unit 60 may be omitted. In this case, switching from the pre-cooling operation to the steady operation and switching from the steady operation to the refrigerator temperature raising operation are performed manually.

  Moreover, the cooling flow path 52 may be omitted.

DESCRIPTION OF SYMBOLS 1 Superconducting magnet apparatus 10 Superconducting coil 12 Radiation shield 14 Vacuum container 20 Refrigerator 21 1st cooling stage 22 2nd cooling stage 23 Attaching part 30 Working medium flow path 31 1st heat exchange part (refrigerant heat exchange part)
32 2nd heat exchange part (refrigerator heat exchange part)
33 3rd heat exchange part (coil heat exchange part)
40 pump 41 first heat exchanger 42 second heat exchanger 52 cooling channel 53 cooling unit 54 heat exchanger avoiding channel 55 heating unit 56 coil avoiding channel 57 heating unit 60 switching unit

Claims (4)

A superconducting coil;
A vacuum vessel containing the superconducting coil;
A refrigerator that can be detachably attached to the vacuum vessel;
A gas phase working medium in the order of the refrigerator heat exchange unit and the coil heat exchange unit, including a refrigerator heat exchange unit thermally contacting the refrigerator and a coil heat exchange unit thermally contacting the superconducting coil A working medium flow path for flowing
A coil avoidance flow path for deriving the gas phase working medium out of the vacuum vessel from a portion between the refrigerator heat exchange section and the coil heat exchange section of the working medium flow path, Superconducting magnet device. In the superconducting magnet device according to claim 1,
A superconducting magnet apparatus, further comprising a pump that is disposed outside the vacuum vessel and that sends a vapor-phase working medium that has flowed out of the vacuum vessel through the working medium flow path to the refrigerator heat exchange unit. In the superconducting magnet device according to claim 2,
The downstream end of the coil avoidance flow path is connected to a portion of the working medium flow path outside the vacuum vessel and upstream of the pump,
The coil avoidance flow path has a heating unit that heats the working medium outside the vacuum vessel. In the superconducting magnet device according to any one of claims 1 to 3,
Receives a signal indicating that maintenance of the refrigerator is performed in a steady operation in which the refrigerator is driven and the gas phase working medium flows in the order of the refrigerator heat exchange unit and the coil heat exchange unit. A switching unit for stopping the refrigerator and switching from the steady operation to a refrigerator heating operation in which the gas phase working medium flows in the order of the refrigerator heat exchange unit and the coil avoidance flow path. A superconducting magnet device.

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