WO2021181615A1 - Superconducting magnet - Google Patents

Superconducting magnet Download PDF

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Publication number
WO2021181615A1
WO2021181615A1 PCT/JP2020/010867 JP2020010867W WO2021181615A1 WO 2021181615 A1 WO2021181615 A1 WO 2021181615A1 JP 2020010867 W JP2020010867 W JP 2020010867W WO 2021181615 A1 WO2021181615 A1 WO 2021181615A1
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WIPO (PCT)
Prior art keywords
superconducting coil
superconducting
cooling pipe
heat
switch unit
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Application number
PCT/JP2020/010867
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French (fr)
Japanese (ja)
Inventor
英明 三浦
彰一 横山
航大 野村
Original Assignee
三菱電機株式会社
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Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2021526266A priority Critical patent/JP6945771B1/en
Priority to PCT/JP2020/010867 priority patent/WO2021181615A1/en
Publication of WO2021181615A1 publication Critical patent/WO2021181615A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/04—Cooling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor

Definitions

  • This disclosure relates to superconducting magnets.
  • Patent Document 1 is a prior document that discloses the configuration of a superconducting magnet.
  • the superconducting magnet described in Patent Document 1 includes a superconducting coil, a heat conductor, a heat shield, a vacuum container, and a refrigerator.
  • the superconducting coil is in a superconducting state at extremely low temperatures.
  • the thermal conductor consists of a good conductor of heat and surrounds the superconducting coil.
  • the heat shield surrounds the heat conductor to shield the radiant heat from the outside.
  • the vacuum vessel contains a heat conductor and a heat shield that surrounds the superconducting coil. The inside of the vacuum vessel is kept in a vacuum.
  • the refrigerator is mounted so as to project into the vacuum vessel.
  • the refrigerator has an intermediate cooling unit and a cryogenic cooling unit.
  • the heat shield is thermally connected to the intermediate cooling part of the refrigerator.
  • the heat conductor is thermally connected to the cryogenic cooling part of the refrigerator.
  • a cooling tube is attached to the heat conductor so that the cooling medium can be appropriately distributed. The liquid refrigerant injected from the injection port flows through the cooling pipe, flows into the service port, and is discharged from the discharge port.
  • the cooling medium can be circulated through the cooling pipe attached to the heat conductor to quickly cool the heat.
  • the present disclosure has been made in view of the above object, and an object of the present disclosure is to provide a superconducting magnet that reduces the amount of heat that enters the superconducting coil via a cooling pipe in a steady state.
  • the superconducting magnet based on the present disclosure includes a superconducting coil, a vacuum container, a radiation shield, a refrigerator, a cooling tube, and a heat switch section.
  • the vacuum vessel houses the superconducting coil.
  • the radiation shield is arranged between the superconducting coil and the vacuum vessel.
  • the radiation shield surrounds the superconducting coil.
  • the refrigerator is connected to the superconducting coil from the outside of the vacuum vessel.
  • the refrigerator includes a first stage and a second stage. The first stage is connected to the radiation shield. The second stage is connected to the superconducting coil.
  • a cooling medium can pass through the cooling pipe.
  • the cooling tube extends from the outside of the vacuum vessel toward the superconducting coil. A part of the cooling pipe is located inside the vacuum vessel.
  • the thermal switch section is located at least in the region between the superconducting coil and the radiation shield.
  • the thermal switch section is connected to the superconducting coil.
  • the thermal switch unit may take a first state and a second state. In the second state, the heat switch unit is configured to be changeable so that the thermal conductivity between the superconducting coil and the cooling tube is lower than that in the first state.
  • the heat switch portion when the superconducting coil is cooled from room temperature, the heat switch portion is set to the first state, so that the superconducting coil is cooled by the refrigerator and the cooling pipe to improve the cooling efficiency, and the cooling time is improved.
  • the amount of heat that enters the superconducting coil via the cooling pipe can be reduced by setting the heat switch portion to the second state.
  • FIG. 1 is a cross-sectional view showing the configuration of a superconducting magnet according to the first embodiment.
  • the superconducting magnet 100 according to the first embodiment includes a superconducting coil 110, a vacuum container 120, a radiation shield 130, a refrigerator 140, a cooling pipe 150, and a heat switch unit 160. ing.
  • the superconducting coil 110 is formed by winding a superconducting wire. In the steady operation state of the superconducting magnet, the superconducting coil 110 is in the superconducting state.
  • Superconducting wires contain copper as the main material.
  • the specific heat of copper decreases as the temperature decreases. For example, copper having a temperature of 50 K has a specific heat about one-fourth that of copper at room temperature. Copper having a temperature of 20 K has a specific heat of about 1/50 of that of copper at room temperature.
  • the superconducting coil 110 has a heat conductive member (not shown) provided so as to surround the superconducting wire. That is, the member connected to the superconducting coil 110 from the outside of the superconducting coil 110 is specifically connected to the heat conductive member of the superconducting coil 110.
  • the thermal conductivity of the heat conductive member is preferably relatively high.
  • the heat conductive member is made of, for example, copper or aluminum.
  • the vacuum container 120 houses the superconducting coil 110.
  • the inside of the vacuum vessel 120 is maintained in a vacuum state.
  • the radiation shield 130 is arranged between the superconducting coil 110 and the vacuum vessel 120.
  • the radiation shield 130 surrounds the superconducting coil 110.
  • the radiation shield 130 is supported by the vacuum vessel 120 via a support member (not shown).
  • the support member is preferably made of a member having a relatively low thermal conductivity, and is preferably made of, for example, glass fiber reinforced plastic (GFRP: Grass Fiber Reinforced Plastics) or ceramics.
  • the refrigerator 140 is connected to the superconducting coil 110 from the outside of the vacuum container 120.
  • the refrigerator 140 includes a first stage 141 and a second stage 142.
  • the temperature of the second stage 142 is configured to be lower than the temperature of the first stage 141.
  • the temperature of the first stage 141 is, for example, about 50 K
  • the temperature of the second stage 142 is, for example, about 10 K or less.
  • the first stage 141 is connected to the radiation shield 130. Thereby, in the present embodiment, the first stage 141 can cool the radiant shield 130 so that the temperature of the radiant shield 130 becomes about 50 K.
  • the second stage 142 is connected to the superconducting coil 110. Thereby, in the present embodiment, the second stage 142 can cool the superconducting coil 110 so that the temperature of the superconducting coil 110 is about 20 K or less.
  • the refrigerator 140 is, for example, a Gifford-McMahon type refrigerator or a pulse tube refrigerator.
  • FIG. 2 is a perspective view showing a cooling tube in the superconducting magnet according to the first embodiment.
  • the cooling pipe 150 extends from the outside of the vacuum vessel 120 toward the superconducting coil 110.
  • a part of the cooling pipe 150 is located inside the vacuum container 120.
  • the portion located inside the cooling pipe 150 has a meandering shape.
  • Each of one end and the other end of the cooling tube 150 is located outside the vacuum vessel 120.
  • the cooling medium can pass through the cooling pipe 150.
  • the cooling medium include liquid nitrogen, liquid helium, and liquid hydrogen.
  • the portion of the cooling pipe 150 through which the cooling medium flows is preferably composed of a seamless tubular wall.
  • the cooling pipe 150 has a first valve 151, a second valve 152, and a check valve 153.
  • the first valve 151 is provided on one end side of the cooling pipe 150 on the outside of the vacuum vessel 120.
  • the second valve 152 is provided on the other end side of the cooling pipe 150 on the outside of the vacuum vessel 120.
  • the cooling pipe 150 is configured so that the cooling medium can be confined in the cooling pipe 150 by closing both the first valve 151 and the second valve 152.
  • the check valve 153 is provided on one end side or the other end side of the cooling pipe 150. In the present embodiment, the check valve 153 is provided on one end side of the cooling pipe 150.
  • the check valve 153 does not allow gas to flow into the inside of the cooling pipe 150 from the outside, and when the pressure inside the cooling pipe 150 becomes too high, the gas can flow out from the inside of the cooling pipe 150 to the outside. It is configured as follows. In the present embodiment, the check valve 153 does not necessarily have to be provided in the cooling pipe 150.
  • a controller 154 is connected to each of the first valve 151 and the second valve 152.
  • the controller 154 may close each of the first valve 151 and the second valve 152 when the temperature value of the radiation shield 130 or the heat switch unit 160 that directly contacts the cooling pipe 150 becomes lower than the threshold value. It is configured so that it can be done.
  • the threshold value may be specifically the boiling point of the cooling medium flowing through the cooling pipe 150.
  • the superconducting magnet 100 is configured so that the pressure inside the cooling pipe 150 can be maintained at 1 atm or more in a steady operation state. Specifically, the pressure of the cooling pipe 150 is set to 1 by opening and closing the first valve 151 and the second valve 152, or by providing the check valve 153 in a steady operation state. Maintained above atmospheric pressure.
  • the thermal switch unit 160 is located at least in the region between the superconducting coil 110 and the radiation shield 130.
  • the heat switch unit 160 is connected to the superconducting coil 110.
  • the heat switch unit 160 is in contact with the cooling pipe 150 via the radiation shield 130 on the side opposite to the superconducting coil 110 side.
  • the heat switch unit 160 may be in direct contact with the cooling pipe 150 on the side opposite to the superconducting coil 110 side. That is, the heat switch unit 160 is arranged so that heat can be propagated between the cooling pipe 150 and the superconducting coil 110.
  • the heat switch unit 160 can take a first state and a second state. In the second state, the heat switch unit 160 is configured to be changeable so that the thermal conductivity between the superconducting coil 110 and the cooling pipe 150 is lower than that in the first state.
  • the heat switch unit 160 include a mechanical heat switch and a solid-state heat switch.
  • the heat switch unit 160 When the heat switch unit 160 is a mechanical heat switch, the heat switch unit 160 has at least two heat transfer members. In the heat switch unit 160, the two heat transfer members located inside the heat switch unit 160 are in contact with each other in the first state, but in the second state, the two heat transfer members are separated from each other. do. In this way, the thermal conductivity of the heat switch unit 160 can be changed.
  • the thermal switch unit 160 is a mechanical thermal switch, the thermal switch unit 160 is configured so that the first state and the second state can be switched by, for example, an external input signal.
  • the heat switch unit 160 When the heat switch unit 160 is a solid-state heat switch, the heat switch unit 160 has at least a heat transfer member whose thermal conductivity changes depending on the temperature.
  • the heat transfer member is, for example, carbon fiber reinforced plastic.
  • the heat switch unit 160 when the heat transfer member in the heat switch unit 160 has a temperature within the first range, the heat switch unit 160 is in the first state. Temperatures within the first range include room temperature.
  • the heat switch unit 160 has a temperature within the second range composed of a temperature range lower than the first range, the heat switch unit 160 is in the second state.
  • the heat switch unit 160 is configured to be changeable so that the thermal conductivity in the second state is lower than that in the first state, the superconducting coil 110 and the cooling tube 150 are combined. The thermal conductivity between them can be changed.
  • the heat switch unit 160 when the heat switch unit 160 is a mechanical heat switch, the heat switch unit 160 is set to the first state in a state where the superconducting magnet 100 has the same temperature as room temperature.
  • the heat switch unit 160 when the heat switch unit 160 is a solid-type heat switch, the heat switch unit 160 is set so that the heat switch unit 160 is in the first state when the superconducting magnet 100 has the same temperature as room temperature.
  • the heat switch unit 160 is configured in advance so that the heat transfer member is included.
  • the first valve 151 and the second valve 152 of the cooling pipe 150 are opened, and the cooling medium is allowed to flow through the cooling pipe 150. Then, the cooling medium is injected into the cooling pipe 150 to allow it to flow, and the refrigerator 140 is operated. In this way, the heat of the superconducting coil 110 is endothermic by the refrigerator 140 and the cooling pipe 150 via the heat switch unit 160.
  • the heat switch unit 160 is a mechanical heat switch
  • the heat switch unit 160 is brought into the second state at the above time point or before the above time point, or the heat switch unit 160 is a solid type.
  • the heat switch unit is prepared in advance so that the heat switch unit 160 includes the heat transfer member so that the heat switch unit 160 is in the second state at the above time point or before the above time point. 160 is configured.
  • the refrigerator 140 is continuously operated until the superconducting coil 110 is in the superconducting state. In this way, after the above time point, the heat of the superconducting coil 110 is absorbed by the refrigerator 140 while suppressing heat from entering the superconducting coil 110 through the cooling pipe 150. By the above method, the superconducting magnet 100 can be put into a steady operation state.
  • the pressure inside the cooling pipe 150 is maintained at 1 atm or more.
  • the pressure inside the cooling pipe 150 may be controlled by the check valve 153, or the opening degree of at least one of the first valve 151 and the second valve 152 may be controlled manually or by the controller 154.
  • the superconducting magnet 100 includes a superconducting coil 110, a vacuum container 120, a radiation shield 130, a refrigerator 140, a cooling tube 150, and a heat switch unit 160.
  • the vacuum container 120 houses the superconducting coil 110.
  • the radiation shield 130 is arranged between the superconducting coil 110 and the vacuum vessel 120.
  • the radiation shield 130 surrounds the superconducting coil 110.
  • the refrigerator 140 is connected to the superconducting coil 110 from the outside of the vacuum container 120.
  • the refrigerator 140 includes a first stage 141 and a second stage 142.
  • the first stage 141 is connected to the radiation shield 130.
  • the second stage 142 is connected to the superconducting coil 110.
  • the cooling medium can pass through the cooling pipe 150.
  • the cooling pipe 150 extends from the outside of the vacuum vessel 120 toward the superconducting coil 110. A part of the cooling pipe 150 is located inside the vacuum container 120.
  • the thermal switch unit 160 is located at least in the region between the superconducting coil 110 and the radiation shield 130. The heat switch unit 160 is connected to the superconducting coil 110.
  • the heat switch unit 160 may take a first state and a second state. In the second state, the heat switch unit 160 is configured to be changeable so that the thermal conductivity between the superconducting coil 110 and the cooling pipe 150 is lower than that in the first state.
  • the heat switch unit 160 is set to the first state, so that the superconducting coil 110 is cooled by the refrigerator 140 and the cooling pipe 150 to improve the cooling efficiency.
  • the cooling time can be shortened, and when the superconducting coil 110 is in a steady operation state, the heat switch unit 160 is set to the second state, so that the amount of heat that enters the superconducting coil 110 via the cooling pipe 150 is the amount of heat. Can be reduced.
  • the heat switch unit 160 When the temperature of the superconducting magnet 100 according to the first embodiment is raised from a steady state to a state having the same temperature as room temperature, the heat switch unit 160 is set to the first state to increase the temperature rise time. It can also be shortened.
  • the heat switch unit 160 is in contact with the cooling pipe 150 via the radiation shield 130 on the side opposite to the superconducting coil 110 side.
  • the amount of heat that penetrates from the outside to the inside of the radiant shield 130 can be reduced as compared with the case where the cooling pipe 150 is directly connected to the superconducting coil 110, that is, it penetrates the radiant shield 130. ..
  • the superconducting magnet 100 according to the first embodiment is configured so that the pressure inside the cooling pipe 150 can be maintained at 1 atm or more in a steady operation state.
  • the cooling pipe 150 has a first valve 151, a second valve 152, and a check valve 153.
  • the first valve 151 is provided on one end side of the cooling pipe 150 on the outside of the vacuum vessel 120.
  • the second valve 152 is provided on the other end side of the cooling pipe 150 on the outside of the vacuum vessel 120.
  • the check valve 153 is provided on one end side or the other end side of the cooling pipe 150.
  • the state in which the refrigerant is located in the cooling pipe 150 can be maintained in the steady state.
  • the amount of heat that enters the superconducting coil 110 via the cooling pipe 150 in the steady state can be further reduced.
  • the controller 154 is connected to each of the first valve 151 and the second valve 152.
  • the controller 154 may close each of the first valve 151 and the second valve 152 when the temperature value of the radiation shield 130 or the heat switch unit 160 that directly contacts the cooling pipe 150 becomes lower than the threshold value. It is configured so that it can be done.
  • each of the first valve 151 and the second valve 152 is automatically closed to form a cooling pipe.
  • the amount of heat that enters the superconducting coil 110 via the 150 can be further reduced.
  • Embodiment 2 the superconducting magnet according to the second embodiment will be described.
  • the superconducting magnet according to the second embodiment differs from the superconducting magnet 100 according to the first embodiment only in the configuration of the thermal switch portion. Therefore, the description of the configuration similar to that of the superconducting magnet 100 according to the first embodiment will not be repeated.
  • FIG. 3 is a cross-sectional view showing the configuration of the superconducting magnet according to the second embodiment.
  • FIG. 4 is a cross-sectional view showing a thermal switch portion in the superconducting magnet according to the second embodiment.
  • the heat switch unit 260 is a solid-state heat switch.
  • the heat switch unit 260 contains carbon fiber reinforced plastic 261.
  • the carbon fiber reinforced plastic 261 whose thermal conductivity decreases as the temperature decreases can automatically switch between the first state and the second state of the heat switch unit 260.
  • the carbon fiber reinforced plastic 261 is, for example, when the temperature of the carbon fiber reinforced plastic 261 is 50 K or less, as compared with the case where the temperature of the carbon fiber reinforced plastic 261 is higher than 50 K and lower than room temperature. , The thermal conductivity is significantly reduced.
  • the thermal conductivity of 50K carbon fiber reinforced plastic 261 is about 1/10 of the thermal conductivity of carbon fiber reinforced plastic 261 at room temperature. That is, in the present embodiment, the first range of the temperature of the heat switch unit 260 can be seen as, for example, higher than 50K and below room temperature, and the second range is less than 50K.
  • the thermal switch unit 260 contains the carbon fiber reinforced plastic 261 having the above-mentioned characteristics, in particular, the room temperature at which the specific heat of copper contained in the superconducting coil 110 as the main material becomes relatively large.
  • the temperature range from 1 to 50 K the cooling efficiency of cooling the superconducting coil 110 by the refrigerator 140 and the cooling pipe 150 can be improved.
  • the cooling time of the superconducting coil 110 in the above temperature range can be further shortened.
  • the heat switch unit 260 further includes a first heat transfer unit 262 and a second heat transfer unit 263.
  • the first heat transfer section 262 is located on the superconducting coil 110 side of the carbon fiber reinforced plastic 261.
  • the second heat transfer section 263 is located on the side opposite to the superconducting coil 110 side of the carbon fiber reinforced plastic 261.
  • Each of the first heat transfer section 262 and the second heat transfer section 263 is made of a material having a relatively large thermal conductivity, for example, copper or aluminum. Further, it is preferable that the first heat transfer section 262 and the second heat transfer section 263 are made of a material having good workability.
  • the carbon fiber reinforced plastic 261 has a plurality of carbon fibers 265. At least a part of the plurality of carbon fibers 265 extends in parallel with each other, but the extending direction is not particularly limited.
  • Embodiment 3 the superconducting magnet according to the third embodiment will be described.
  • the superconducting magnet according to the third embodiment is different from the superconducting magnet 200 according to the second embodiment in the composition of the plurality of carbon fibers in the carbon fiber reinforced plastic. Therefore, the description of the configuration similar to that of the superconducting magnet 200 according to the second embodiment will not be repeated.
  • FIG. 5 is a cross-sectional view showing a thermal switch portion in the superconducting magnet according to the third embodiment.
  • the carbon fiber reinforced plastic 361 has a plurality of first carbon fibers 365A and a plurality of second carbon fibers 365B.
  • the plurality of first carbon fibers 365A extend parallel to each other.
  • Each of the plurality of second carbon fibers 365B extends in a direction orthogonal to the extending direction of the plurality of first carbon fibers 365A when viewed from a direction orthogonal to the extending direction of the plurality of first carbon fibers 365A. doing.
  • each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B intersects the direction from the superconducting coil 110 side to the opposite side in the thermal switch portion 360.
  • the extending directions of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B and the opposite side from the superconducting coil 110 side in the thermal switch portion 360 is about 45 degrees.
  • FIG. 6 is a graph showing an example of experimental results in which the thermal conductivity of the carbon fiber reinforced plastic in the third embodiment was measured for each temperature of the carbon fiber reinforced plastic in each of the first direction and the second direction. ..
  • the angles formed by the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B with respect to the extending directions are formed when viewed from the orthogonal direction.
  • the thermal conductivity in the first direction which is the direction of 45 degrees, was defined as the first thermal conductivity and is shown at plot point A. Also.
  • the angle formed by each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B with respect to the extending direction is 0 degree or 90 degrees.
  • the thermal conductivity in the two directions was defined as the second thermal conductivity and is shown at plot point B.
  • the second thermal conductivity is 80 times higher when the temperature of the carbon fiber reinforced plastic is room temperature as compared with the case where the temperature of the carbon fiber reinforced plastic is 20 K, whereas the first thermal conductivity is 80 times higher.
  • the thermal conductivity is 130 times.
  • the carbon fiber reinforced plastic 361 in the present embodiment has the extension of each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B in the temperature region near room temperature.
  • Embodiment 4 the superconducting magnet according to the fourth embodiment will be described.
  • the superconducting magnet according to the fourth embodiment is different from the superconducting magnet 100 according to the first embodiment mainly in the configuration of the thermal switch portion. Therefore, the description of the configuration similar to that of the superconducting magnet 100 according to the first embodiment will not be repeated.
  • FIG. 7 is a perspective view showing a cooling tube and a heat switch portion in the superconducting magnet according to the fourth embodiment.
  • the heat switch unit 460 is in direct contact with the cooling pipe 150 on the side opposite to the superconducting coil 110 side.
  • the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be improved as compared with the case where the cooling pipe 150 is connected to the superconducting coil 110 via the radiation shield 130.
  • the heat switch unit 460 is one or more carbon fibers.
  • the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be further improved by directly connecting the carbon fibers having high thermal conductivity and functioning as a heat switch to the cooling pipe 150.
  • the heat switch unit 460 can be provided with a simple configuration.
  • the thermal conductivity of the carbon fiber in the temperature range of about 50 K or more and room temperature or less is significantly higher than that in the temperature range of less than about 50 K. Therefore, also in the present embodiment, the superconducting coil 110 is cooled by the refrigerator 140 and the cooling pipe 150 in the temperature range from room temperature to 50 K where the specific heat of copper contained in the superconducting coil 110 as a main material is relatively large. Cooling efficiency can be improved. As a result, the cooling time of the superconducting coil 110 in the above temperature range can be further shortened.
  • the heat switch unit 460 is in contact with the cooling pipe 150 in a state of being wound around the cooling pipe 150.
  • the contact area between the heat switch portion 460 and the cooling pipe 150 becomes large, and the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be significantly improved.
  • the number of times each of the plurality of carbon fibers wound around the cooling pipe 150 as the heat switch unit 460 may be one or a plurality of times. At least one end of the carbon fiber is attached to the superconducting coil 110 via, for example, a heat conductive member (not shown) provided so as to surround the superconducting wire or another heat conductive member (not shown) provided on the heat conductive member. Be connected.
  • Embodiment 5 the superconducting magnet according to the fifth embodiment will be described.
  • the superconducting magnet according to the fifth embodiment is different from the superconducting magnet according to the fourth embodiment mainly in the configuration of the thermal switch portion. Therefore, the description of the configuration similar to that of the superconducting magnet according to the fourth embodiment will not be repeated.
  • FIG. 8 is a perspective view showing a cooling tube and a heat switch portion in the superconducting magnet according to the fifth embodiment.
  • the heat switch unit 560 is one or a plurality of sheet-shaped carbon fiber reinforced plastics. As a result, the heat switch unit 560 can be wound around the cooling pipe 150.
  • each of the heat switch portions 560 which are a plurality of sheet-shaped carbon fiber reinforced plastics, is wound around the cooling pipe 150.
  • the contact area between the heat switch portion 560 and the cooling pipe 150 can be increased, and the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be further improved.
  • Each of the plurality of sheet-shaped carbon fiber reinforced plastics may be fixed to the cooling pipe 150 via an adhesive, or may be fixed by bolting.

Abstract

A cooling pipe (150) allows a cooling medium to flow therethrough. The cooling pipe (150) extends from the outside of a vacuum container (120) towards a superconducting coil (110). Part of the cooling pipe (150) is positioned inside the vacuum container (120). A heat switch unit (160) is positioned at least in a region between the superconducting coil (110) and a radiation shield (130). The heat switch unit (160) is connected to the superconducting coil (110). The heat switch unit (160) is configured so as to be changeable such that the thermal conductance between the superconducting coil (110) and the cooling pipe (150) is lower in a second state, compared to a first state.

Description

超電導マグネットSuperconducting magnet
　本開示は、超電導マグネットに関する。 This disclosure relates to superconducting magnets.
　超電導マグネットの構成を開示した先行文献として、特許第２６０５９３７号(特許文献１)がある。特許文献１に記載の超電導マグネットは、超電導コイルと、熱伝導体と、熱シールドと、真空容器と、冷凍機とを備えている。超電導コイルは、極低温下で超電導状態になる。熱伝導体は、熱の良導体からなり超電導コイルを包囲する。熱シールドは、熱伝導体を包囲して外部からの輻射熱を遮蔽する。真空容器は、超電導コイルを包囲した熱伝導体および熱シールドを収容している。真空容器の内部は真空に保持されている。冷凍機は、真空容器内に突出して取り付けられている。冷凍機は、中間冷却部および極低温冷却部を有している。熱シールドは、冷凍機の中間冷却部と熱接続されている。熱伝導体は冷凍機の極低温冷却部と熱接続されている。熱伝導体には、冷却媒体を適宜流通可能とした冷却管が取付けられている。注液口から注入された液体冷媒は冷却管を流れてサービスポートに流入し、排出口から排出される。 Patent No. 2605937 (Patent Document 1) is a prior document that discloses the configuration of a superconducting magnet. The superconducting magnet described in Patent Document 1 includes a superconducting coil, a heat conductor, a heat shield, a vacuum container, and a refrigerator. The superconducting coil is in a superconducting state at extremely low temperatures. The thermal conductor consists of a good conductor of heat and surrounds the superconducting coil. The heat shield surrounds the heat conductor to shield the radiant heat from the outside. The vacuum vessel contains a heat conductor and a heat shield that surrounds the superconducting coil. The inside of the vacuum vessel is kept in a vacuum. The refrigerator is mounted so as to project into the vacuum vessel. The refrigerator has an intermediate cooling unit and a cryogenic cooling unit. The heat shield is thermally connected to the intermediate cooling part of the refrigerator. The heat conductor is thermally connected to the cryogenic cooling part of the refrigerator. A cooling tube is attached to the heat conductor so that the cooling medium can be appropriately distributed. The liquid refrigerant injected from the injection port flows through the cooling pipe, flows into the service port, and is discharged from the discharge port.
　超伝導装置の冷却は定常状態であれば、１台の冷凍機で十分な冷却能力があるが、超電導コイルの運転開始するとき、初期冷却、初期励磁のときは１台の冷却系統では能力が不足する。このため、熱伝導体に取り付けられた冷却管に冷却媒体を流通させて早く冷却することができる。 If the superconducting device is cooled in a steady state, one refrigerator has sufficient cooling capacity, but when the superconducting coil starts operation, the initial cooling and initial excitation can be achieved by one cooling system. Run short. Therefore, the cooling medium can be circulated through the cooling pipe attached to the heat conductor to quickly cool the heat.
特許第２６０５９３７号Patent No. 2605937
　特許文献１に記載の超電導マグネットが定常運転状態のとき、真空容器の外部から冷却管を介して超電導コイルに熱が侵入する。定常運転状態のときに超電導コイルに熱が侵入すると、冷凍機による冷却効率が低下したり、超電導コイルの温度が上昇する場合がある。 When the superconducting magnet described in Patent Document 1 is in a steady operation state, heat enters the superconducting coil from the outside of the vacuum vessel via a cooling pipe. If heat enters the superconducting coil during steady operation, the cooling efficiency of the refrigerator may decrease or the temperature of the superconducting coil may rise.
　本開示は上記の目的に鑑みてなされたものであり、定常状態において冷却管を介して超電導コイルに侵入する熱の熱量を低減する超電導マグネットを提供することを目的とする。 The present disclosure has been made in view of the above object, and an object of the present disclosure is to provide a superconducting magnet that reduces the amount of heat that enters the superconducting coil via a cooling pipe in a steady state.
　本開示に基づく超電導マグネットは、超電導コイルと、真空容器と、輻射シールドと、冷凍機と、冷却管と、熱スイッチ部とを備えている。真空容器は、超電導コイルを収容している。輻射シールドは、超電導コイルと真空容器との間に配置されている。輻射シールドは、超電導コイルの周りを囲んでいる。冷凍機は、真空容器の外側から超電導コイルに接続されている。冷凍機は、第１ステージおよび第２ステージを含んでいる。第１ステージは、輻射シールドと接続されている。第２ステージは、超電導コイルと接続されている。冷却管は、冷却媒体が通流可能である。冷却管は、真空容器の外側から超電導コイルに向かって延びている。冷却管は、真空容器の内部に一部が位置している。熱スイッチ部は、少なくとも超電導コイルと輻射シールドとの間の領域に位置している。熱スイッチ部は、超電導コイルに接続されている。熱スイッチ部は、第１の状態と第２の状態とをとり得る。熱スイッチ部は、第２の状態においては、第１の状態と比較して、超電導コイルと冷却管との間の熱伝導率が低くなるように変更可能に構成されている。 The superconducting magnet based on the present disclosure includes a superconducting coil, a vacuum container, a radiation shield, a refrigerator, a cooling tube, and a heat switch section. The vacuum vessel houses the superconducting coil. The radiation shield is arranged between the superconducting coil and the vacuum vessel. The radiation shield surrounds the superconducting coil. The refrigerator is connected to the superconducting coil from the outside of the vacuum vessel. The refrigerator includes a first stage and a second stage. The first stage is connected to the radiation shield. The second stage is connected to the superconducting coil. A cooling medium can pass through the cooling pipe. The cooling tube extends from the outside of the vacuum vessel toward the superconducting coil. A part of the cooling pipe is located inside the vacuum vessel. The thermal switch section is located at least in the region between the superconducting coil and the radiation shield. The thermal switch section is connected to the superconducting coil. The thermal switch unit may take a first state and a second state. In the second state, the heat switch unit is configured to be changeable so that the thermal conductivity between the superconducting coil and the cooling tube is lower than that in the first state.
　本開示によれば、超電導コイルを常温から冷却するときには、熱スイッチ部を第１の状態とすることで、冷凍機と冷却管とによって超電導コイルを冷却して冷却効率を向上させて、冷却時間を短縮することができるとともに、超電導マグネットが定常運転状態のときは、熱スイッチ部を第２の状態とすることで、冷却管を介して超電導コイルに侵入する熱の熱量を低減できる。 According to the present disclosure, when the superconducting coil is cooled from room temperature, the heat switch portion is set to the first state, so that the superconducting coil is cooled by the refrigerator and the cooling pipe to improve the cooling efficiency, and the cooling time is improved. When the superconducting magnet is in the steady operation state, the amount of heat that enters the superconducting coil via the cooling pipe can be reduced by setting the heat switch portion to the second state.
実施の形態１に係る超電導マグネットの構成を示す断面図である。It is sectional drawing which shows the structure of the superconducting magnet which concerns on Embodiment 1. FIG. 実施の形態１に係る超電導マグネットにおける冷却管を示す斜視図である。It is a perspective view which shows the cooling tube in the superconducting magnet which concerns on Embodiment 1. FIG. 実施の形態２に係る超電導マグネットの構成を示す断面図である。It is sectional drawing which shows the structure of the superconducting magnet which concerns on Embodiment 2. FIG. 実施の形態２に係る超電導マグネットにおける熱スイッチ部を示す断面図である。It is sectional drawing which shows the thermal switch part in the superconducting magnet which concerns on Embodiment 2. FIG. 実施の形態３に係る超電導マグネットにおける熱スイッチ部を示す断面図である。It is sectional drawing which shows the thermal switch part in the superconducting magnet which concerns on Embodiment 3. FIG. 実施の形態３における炭素繊維強化プラスチックの、第１方向および第２方向の各々の熱伝導率を、炭素繊維強化プラスチックの各温度毎に測定した実験結果の一例を示すグラフである。It is a graph which shows an example of the experimental result which measured the thermal conductivity of each of the 1st direction and the 2nd direction of the carbon fiber reinforced plastic in Embodiment 3 for each temperature of the carbon fiber reinforced plastic. 実施の形態４に係る超電導マグネットにおける冷却管および熱スイッチ部を示す斜視図である。It is a perspective view which shows the cooling tube and the heat switch part in the superconducting magnet which concerns on Embodiment 4. FIG. 実施の形態５に係る超電導マグネットにおける冷却管および熱スイッチ部を示す斜視図である。It is a perspective view which shows the cooling tube and the heat switch part in the superconducting magnet which concerns on embodiment 5.
　以下、各実施の形態に係る超電導マグネットについて図面を参照して説明する。以下の実施の形態においては、図中の同一または相当部分には同一符号を付し、その説明は繰り返さない。 Hereinafter, the superconducting magnets according to each embodiment will be described with reference to the drawings. In the following embodiments, the same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.
　実施の形態１．
　図１は、実施の形態１に係る超電導マグネットの構成を示す断面図である。図１に示すように、実施の形態１に係る超電導マグネット１００は、超電導コイル１１０と、真空容器１２０と、輻射シールド１３０と、冷凍機１４０と、冷却管１５０と、熱スイッチ部１６０とを備えている。 Embodiment 1.
FIG. 1 is a cross-sectional view showing the configuration of a superconducting magnet according to the first embodiment. As shown in FIG. 1, the superconducting magnet 100 according to the first embodiment includes a superconducting coil 110, a vacuum container 120, a radiation shield 130, a refrigerator 140, a cooling pipe 150, and a heat switch unit 160. ing.
　超電導コイル１１０は、超電導線が巻き回されて形成されている。超電導マグネットの定常運転状態において、超電導コイル１１０は、超電導状態である。超電導線は、主材料として、銅を含んでいる。なお、銅は、温度が低くなるに従って比熱が小さくなる。たとえば、温度が５０Ｋの銅は、室温の銅と比較して比熱が約４分の１となる。温度が２０Ｋの銅は、室温の銅と比較して比熱が約５０分の１となる。 The superconducting coil 110 is formed by winding a superconducting wire. In the steady operation state of the superconducting magnet, the superconducting coil 110 is in the superconducting state. Superconducting wires contain copper as the main material. The specific heat of copper decreases as the temperature decreases. For example, copper having a temperature of 50 K has a specific heat about one-fourth that of copper at room temperature. Copper having a temperature of 20 K has a specific heat of about 1/50 of that of copper at room temperature.
　本実施の形態において、超電導コイル１１０は、超電導線を包囲するように設けられた図示しない熱伝導部材を有している。すなわち、超電導コイル１１０の外側から超電導コイル１１０に接続される部材は、具体的には、超電導コイル１１０が有する熱伝導部材に接続される。熱伝導部材の熱伝導率は比較的大きいことが好ましい。熱伝導部材は、たとえば銅またはアルミニウムで構成されている。 In the present embodiment, the superconducting coil 110 has a heat conductive member (not shown) provided so as to surround the superconducting wire. That is, the member connected to the superconducting coil 110 from the outside of the superconducting coil 110 is specifically connected to the heat conductive member of the superconducting coil 110. The thermal conductivity of the heat conductive member is preferably relatively high. The heat conductive member is made of, for example, copper or aluminum.
　真空容器１２０は、超電導コイル１１０を収容している。真空容器１２０の内部は真空状態に維持されている。 The vacuum container 120 houses the superconducting coil 110. The inside of the vacuum vessel 120 is maintained in a vacuum state.
　輻射シールド１３０は、超電導コイル１１０と真空容器１２０との間に配置されている。輻射シールド１３０は、超電導コイル１１０の周りを囲んでいる。輻射シールド１３０は、図示しない支持部材を介して真空容器１２０に支持されている。当該支持部材は、熱伝導率が比較的小さい部材で構成されていることが好ましく、たとえば、ガラスファイバ強化プラスチック(ＧＦＲＰ：Grass Fiber Reinforced Plastics)またはセラミックスなどで構成されていることが好ましい。 The radiation shield 130 is arranged between the superconducting coil 110 and the vacuum vessel 120. The radiation shield 130 surrounds the superconducting coil 110. The radiation shield 130 is supported by the vacuum vessel 120 via a support member (not shown). The support member is preferably made of a member having a relatively low thermal conductivity, and is preferably made of, for example, glass fiber reinforced plastic (GFRP: Grass Fiber Reinforced Plastics) or ceramics.
　冷凍機１４０は、真空容器１２０の外側から超電導コイル１１０に接続されている。冷凍機１４０は、第１ステージ１４１および第２ステージ１４２を含んでいる。冷凍機１４０の定常運転状態において、第２ステージ１４２の温度は、第１ステージ１４１の温度より低くなるように構成されている。冷凍機１４０の定常運転状態において、第１ステージ１４１の温度は、たとえば約５０Ｋであり、第２ステージ１４２の温度は、たとえば約１０Ｋ以下である。 The refrigerator 140 is connected to the superconducting coil 110 from the outside of the vacuum container 120. The refrigerator 140 includes a first stage 141 and a second stage 142. In the steady operation state of the refrigerator 140, the temperature of the second stage 142 is configured to be lower than the temperature of the first stage 141. In the steady operation state of the refrigerator 140, the temperature of the first stage 141 is, for example, about 50 K, and the temperature of the second stage 142 is, for example, about 10 K or less.
　第１ステージ１４１は、輻射シールド１３０と接続されている。これにより、本実施の形態において、第１ステージ１４１は、輻射シールド１３０の温度が約５０Ｋとなるように輻射シールド１３０を冷却することができる。第２ステージ１４２は、超電導コイル１１０と接続されている。これにより、本実施の形態において、第２ステージ１４２は、超電導コイル１１０の温度が約２０Ｋ以下となるように、超電導コイル１１０を冷却することができる。 The first stage 141 is connected to the radiation shield 130. Thereby, in the present embodiment, the first stage 141 can cool the radiant shield 130 so that the temperature of the radiant shield 130 becomes about 50 K. The second stage 142 is connected to the superconducting coil 110. Thereby, in the present embodiment, the second stage 142 can cool the superconducting coil 110 so that the temperature of the superconducting coil 110 is about 20 K or less.
　冷凍機１４０は、具体的には、たとえばギフォード・マクマホン式冷凍機、または、パルスチューブ冷凍機である。 Specifically, the refrigerator 140 is, for example, a Gifford-McMahon type refrigerator or a pulse tube refrigerator.
　図２は、実施の形態１に係る超電導マグネットにおける冷却管を示す斜視図である。図１および図２に示すように、冷却管１５０は、真空容器１２０の外側から超電導コイル１１０に向かって延びている。冷却管１５０は、真空容器１２０の内部に一部が位置している。冷却管１５０の内部に位置する部分は、蛇行した形状である。冷却管１５０の一方端および他方端の各々は、真空容器１２０の外側に位置している。 FIG. 2 is a perspective view showing a cooling tube in the superconducting magnet according to the first embodiment. As shown in FIGS. 1 and 2, the cooling pipe 150 extends from the outside of the vacuum vessel 120 toward the superconducting coil 110. A part of the cooling pipe 150 is located inside the vacuum container 120. The portion located inside the cooling pipe 150 has a meandering shape. Each of one end and the other end of the cooling tube 150 is located outside the vacuum vessel 120.
　冷却管１５０は、冷却媒体が通流可能である。冷却媒体としては、液体窒素、液体ヘリウム、または、液体水素などが挙げられる。冷却管１５０のうち冷却媒体が流通する部分は、継ぎ目のない一体の管状壁で構成されていることが好ましい。 The cooling medium can pass through the cooling pipe 150. Examples of the cooling medium include liquid nitrogen, liquid helium, and liquid hydrogen. The portion of the cooling pipe 150 through which the cooling medium flows is preferably composed of a seamless tubular wall.
　本実施の形態において、冷却管１５０は、第１バルブ１５１と、第２バルブ１５２と、逆止弁１５３とを有している。 In the present embodiment, the cooling pipe 150 has a first valve 151, a second valve 152, and a check valve 153.
　第１バルブ１５１は、真空容器１２０の外側において、冷却管１５０の一方端側に設けられている。第２バルブ１５２は、真空容器１２０の外側において、冷却管１５０の他方端側に設けられている。冷却管１５０は、第１バルブ１５１および第２バルブ１５２の両方を閉状態とすることで、冷却管１５０内に冷却媒体を閉じ込めることができるように構成されている。 The first valve 151 is provided on one end side of the cooling pipe 150 on the outside of the vacuum vessel 120. The second valve 152 is provided on the other end side of the cooling pipe 150 on the outside of the vacuum vessel 120. The cooling pipe 150 is configured so that the cooling medium can be confined in the cooling pipe 150 by closing both the first valve 151 and the second valve 152.
　逆止弁１５３は、冷却管１５０の一方端側または他方端側に設けられている。本実施の形態においては、逆止弁１５３は冷却管１５０の一方端側に設けられている。逆止弁１５３は、外部から冷却管１５０の内部側に気体を流入させず、かつ、冷却管１５０内部の圧力が高くなりすぎたときには冷却管１５０の内部から外部に気体を流出させることができるように構成されている。なお、本実施の形態において、逆止弁１５３は、冷却管１５０に必ずしも設けられていなくてもよい。 The check valve 153 is provided on one end side or the other end side of the cooling pipe 150. In the present embodiment, the check valve 153 is provided on one end side of the cooling pipe 150. The check valve 153 does not allow gas to flow into the inside of the cooling pipe 150 from the outside, and when the pressure inside the cooling pipe 150 becomes too high, the gas can flow out from the inside of the cooling pipe 150 to the outside. It is configured as follows. In the present embodiment, the check valve 153 does not necessarily have to be provided in the cooling pipe 150.
　第１バルブ１５１および第２バルブ１５２の各々には、コントローラ１５４が接続されている。コントローラ１５４は、冷却管１５０に直接接触する輻射シールド１３０または熱スイッチ部１６０の温度の値が閾値より低くなったときに、第１バルブ１５１および第２バルブ１５２の各々を閉状態にすることができるように構成されている。本実施の形態において、上記閾値は、具体的には、冷却管１５０に通流する冷却媒体の沸点とすればよい。 A controller 154 is connected to each of the first valve 151 and the second valve 152. The controller 154 may close each of the first valve 151 and the second valve 152 when the temperature value of the radiation shield 130 or the heat switch unit 160 that directly contacts the cooling pipe 150 becomes lower than the threshold value. It is configured so that it can be done. In the present embodiment, the threshold value may be specifically the boiling point of the cooling medium flowing through the cooling pipe 150.
　実施の形態１に係る超電導マグネット１００は、定常運転状態において、冷却管１５０の内部の圧力が１気圧以上に維持可能に構成されている。具体的には、冷却管１５０の圧力は、第１バルブ１５１および第２バルブ１５２の開閉操作により、または逆止弁１５３を設けることにより、定常運転状態において、冷却管１５０の内部の圧力が１気圧以上に維持される。 The superconducting magnet 100 according to the first embodiment is configured so that the pressure inside the cooling pipe 150 can be maintained at 1 atm or more in a steady operation state. Specifically, the pressure of the cooling pipe 150 is set to 1 by opening and closing the first valve 151 and the second valve 152, or by providing the check valve 153 in a steady operation state. Maintained above atmospheric pressure.
　図１に示すように、熱スイッチ部１６０は、少なくとも超電導コイル１１０と輻射シールド１３０との間の領域に位置している。熱スイッチ部１６０は、超電導コイル１１０に接続されている。 As shown in FIG. 1, the thermal switch unit 160 is located at least in the region between the superconducting coil 110 and the radiation shield 130. The heat switch unit 160 is connected to the superconducting coil 110.
　実施の形態１において、熱スイッチ部１６０は、超電導コイル１１０側とは反対側において、輻射シールド１３０を介して冷却管１５０と接している。なお、熱スイッチ部１６０は、超電導コイル１１０側とは反対側において、直接、冷却管１５０と接していてもよい。すなわち、熱スイッチ部１６０は、冷却管１５０と超電導コイル１１０との間において熱が伝搬可能に配置されている。 In the first embodiment, the heat switch unit 160 is in contact with the cooling pipe 150 via the radiation shield 130 on the side opposite to the superconducting coil 110 side. The heat switch unit 160 may be in direct contact with the cooling pipe 150 on the side opposite to the superconducting coil 110 side. That is, the heat switch unit 160 is arranged so that heat can be propagated between the cooling pipe 150 and the superconducting coil 110.
　熱スイッチ部１６０は、第１の状態と第２の状態とをとり得る。熱スイッチ部１６０は、第２の状態においては、第１の状態と比較して、超電導コイル１１０と冷却管１５０との間の熱伝導率が低くなるように変更可能に構成されている。 The heat switch unit 160 can take a first state and a second state. In the second state, the heat switch unit 160 is configured to be changeable so that the thermal conductivity between the superconducting coil 110 and the cooling pipe 150 is lower than that in the first state.
　熱スイッチ部１６０としては、具体的には、機械式の熱スイッチ、または、固体式の熱スイッチが挙げられる。熱スイッチ部１６０が機械式の熱スイッチの場合、熱スイッチ部１６０は、少なくとも２つの伝熱部材を有している。熱スイッチ部１６０は、第１の状態においては熱スイッチ部１６０の内部に位置する２つの伝熱部材が互いに接触しているが、第２の状態においては、上記２つの伝熱部材が互いに離間する。このようにして熱スイッチ部１６０は熱伝導率が変更可能となっている。熱スイッチ部１６０が機械式の熱スイッチである場合は、熱スイッチ部１６０は、たとえば外部からの入力信号によって第１の状態と第２の状態とが切り替え可能に構成される。 Specific examples of the heat switch unit 160 include a mechanical heat switch and a solid-state heat switch. When the heat switch unit 160 is a mechanical heat switch, the heat switch unit 160 has at least two heat transfer members. In the heat switch unit 160, the two heat transfer members located inside the heat switch unit 160 are in contact with each other in the first state, but in the second state, the two heat transfer members are separated from each other. do. In this way, the thermal conductivity of the heat switch unit 160 can be changed. When the thermal switch unit 160 is a mechanical thermal switch, the thermal switch unit 160 is configured so that the first state and the second state can be switched by, for example, an external input signal.
　熱スイッチ部１６０が固体式の熱スイッチである場合、熱スイッチ部１６０は、少なくとも、温度によって熱伝導率が変化する伝熱部材を有している。当該伝熱部材は、たとえば炭素繊維強化プラスチックである。本実施の形態においては、熱スイッチ部１６０における当該伝熱部材が第１の範囲内の温度のとき、熱スイッチ部１６０が第１の状態となる。第１の範囲内の温度には、室温が含まれる。熱スイッチ部１６０における当該伝熱部材が第１の範囲より低い温度域で構成される第２の範囲内の温度のとき、熱スイッチ部１６０が第２の状態となる。 When the heat switch unit 160 is a solid-state heat switch, the heat switch unit 160 has at least a heat transfer member whose thermal conductivity changes depending on the temperature. The heat transfer member is, for example, carbon fiber reinforced plastic. In the present embodiment, when the heat transfer member in the heat switch unit 160 has a temperature within the first range, the heat switch unit 160 is in the first state. Temperatures within the first range include room temperature. When the heat transfer member in the heat switch unit 160 has a temperature within the second range composed of a temperature range lower than the first range, the heat switch unit 160 is in the second state.
　このように、熱スイッチ部１６０は、第１の状態と比較して、第２の状態の熱伝導率が低くなるように変更可能に構成されているため、超電導コイル１１０と冷却管１５０との間の熱伝導率が変更可能となっている。 As described above, since the heat switch unit 160 is configured to be changeable so that the thermal conductivity in the second state is lower than that in the first state, the superconducting coil 110 and the cooling tube 150 are combined. The thermal conductivity between them can be changed.
　以下、本実施の形態において、室温と同一の温度を有する超電導コイル１１０を冷却して超電導状態にすることで、超電導マグネット１００を定常運転状態にする方法の一例について説明する。 Hereinafter, in the present embodiment, an example of a method of bringing the superconducting magnet 100 into a steady operation state by cooling the superconducting coil 110 having the same temperature as room temperature to bring it into a superconducting state will be described.
　まず、熱スイッチ部１６０が機械式の熱スイッチである場合には、超電導マグネット１００が室温と同一の温度を有する状態において、熱スイッチ部１６０を第１の状態とする。あるいは、熱スイッチ部１６０が固体式の熱スイッチである場合には、超電導マグネット１００が室温と同一の温度を有する状態において熱スイッチ部１６０が第１の状態となるように、熱スイッチ部１６０に上記伝熱部材が含まれるように予め熱スイッチ部１６０を構成しておく。 First, when the heat switch unit 160 is a mechanical heat switch, the heat switch unit 160 is set to the first state in a state where the superconducting magnet 100 has the same temperature as room temperature. Alternatively, when the heat switch unit 160 is a solid-type heat switch, the heat switch unit 160 is set so that the heat switch unit 160 is in the first state when the superconducting magnet 100 has the same temperature as room temperature. The heat switch unit 160 is configured in advance so that the heat transfer member is included.
　次に、冷却管１５０の第１バルブ１５１および第２バルブ１５２を開状態にして、冷却管１５０内に冷却媒体を通流させる。そして、冷却管１５０に冷却媒体を注入して通流させるとともに、冷凍機１４０を運転させる。このようにして、冷凍機１４０と、熱スイッチ部１６０を介した冷却管１５０とによって、超電導コイル１１０の熱を吸熱する。 Next, the first valve 151 and the second valve 152 of the cooling pipe 150 are opened, and the cooling medium is allowed to flow through the cooling pipe 150. Then, the cooling medium is injected into the cooling pipe 150 to allow it to flow, and the refrigerator 140 is operated. In this way, the heat of the superconducting coil 110 is endothermic by the refrigerator 140 and the cooling pipe 150 via the heat switch unit 160.
　そして、冷却管１５０に直接接触する輻射シールド１３０または熱スイッチ部１６０の温度の値が、上記冷却媒体の沸点より低くなった時点で、冷却管１５０への冷却媒体の投入を停止するとともに、第１バルブ１５１および第２バルブ１５２を手動またはコントローラ１５４により閉状態にする。また、熱スイッチ部１６０が機械式の熱スイッチである場合には、上記時点または上記時点よりも前に、熱スイッチ部１６０を第２の状態にする、あるいは、熱スイッチ部１６０が固体式の熱スイッチである場合には、上記時点または上記時点よりも前に、熱スイッチ部１６０が第２の状態となるように、熱スイッチ部１６０に上記伝熱部材が含まれるように予め熱スイッチ部１６０を構成しておく。さらに、冷凍機１４０については、超電導コイル１１０が超電導状態となるまで、運転を継続させる。このようにして、上記時点以後においては、冷却管１５０を介して超電導コイル１１０に熱が侵入することを抑制しつつ、超電導コイル１１０の熱を冷凍機１４０により吸熱する。上記の方法により、超電導マグネット１００を定常運転状態にすることができる。 Then, when the temperature value of the radiation shield 130 or the heat switch unit 160 that directly contacts the cooling pipe 150 becomes lower than the boiling point of the cooling medium, the charging of the cooling medium to the cooling pipe 150 is stopped and the cooling medium is stopped. The 1st valve 151 and the 2nd valve 152 are closed manually or by the controller 154. When the heat switch unit 160 is a mechanical heat switch, the heat switch unit 160 is brought into the second state at the above time point or before the above time point, or the heat switch unit 160 is a solid type. In the case of a heat switch, the heat switch unit is prepared in advance so that the heat switch unit 160 includes the heat transfer member so that the heat switch unit 160 is in the second state at the above time point or before the above time point. 160 is configured. Further, the refrigerator 140 is continuously operated until the superconducting coil 110 is in the superconducting state. In this way, after the above time point, the heat of the superconducting coil 110 is absorbed by the refrigerator 140 while suppressing heat from entering the superconducting coil 110 through the cooling pipe 150. By the above method, the superconducting magnet 100 can be put into a steady operation state.
　なお、上記時点以後および超電導マグネット１００が定常運転状態である場合においては、冷却管１５０の内部の圧力は１気圧以上に維持する。冷却管１５０の内部の圧力は、逆止弁１５３によって制御してもよいし、第１バルブ１５１および第２バルブ１５２の少なくとも一方の開度を手動またはコントローラ１５４により制御してもよい。 After the above time point and when the superconducting magnet 100 is in a steady operation state, the pressure inside the cooling pipe 150 is maintained at 1 atm or more. The pressure inside the cooling pipe 150 may be controlled by the check valve 153, or the opening degree of at least one of the first valve 151 and the second valve 152 may be controlled manually or by the controller 154.
　上記のように、実施の形態１に係る超電導マグネット１００は、超電導コイル１１０と、真空容器１２０と、輻射シールド１３０と、冷凍機１４０と、冷却管１５０と、熱スイッチ部１６０とを備えている。真空容器１２０は、超電導コイル１１０を収容している。輻射シールド１３０は、超電導コイル１１０と真空容器１２０との間に配置されている。輻射シールド１３０は、超電導コイル１１０の周りを囲んでいる。冷凍機１４０は、真空容器１２０の外側から超電導コイル１１０に接続されている。冷凍機１４０は、第１ステージ１４１および第２ステージ１４２を含んでいる。第１ステージ１４１は、輻射シールド１３０と接続されている。第２ステージ１４２は、超電導コイル１１０と接続されている。冷却管１５０は、冷却媒体が通流可能である。冷却管１５０は、真空容器１２０の外側から超電導コイル１１０に向かって延びている。冷却管１５０は、真空容器１２０の内部に一部が位置している。熱スイッチ部１６０は、少なくとも超電導コイル１１０と輻射シールド１３０との間の領域に位置している。熱スイッチ部１６０は、超電導コイル１１０に接続されている。熱スイッチ部１６０は、第１の状態と第２の状態とをとり得る。熱スイッチ部１６０は、第２の状態においては、第１の状態と比較して、超電導コイル１１０と冷却管１５０との間の熱伝導率が低くなるように変更可能に構成されている。 As described above, the superconducting magnet 100 according to the first embodiment includes a superconducting coil 110, a vacuum container 120, a radiation shield 130, a refrigerator 140, a cooling tube 150, and a heat switch unit 160. .. The vacuum container 120 houses the superconducting coil 110. The radiation shield 130 is arranged between the superconducting coil 110 and the vacuum vessel 120. The radiation shield 130 surrounds the superconducting coil 110. The refrigerator 140 is connected to the superconducting coil 110 from the outside of the vacuum container 120. The refrigerator 140 includes a first stage 141 and a second stage 142. The first stage 141 is connected to the radiation shield 130. The second stage 142 is connected to the superconducting coil 110. The cooling medium can pass through the cooling pipe 150. The cooling pipe 150 extends from the outside of the vacuum vessel 120 toward the superconducting coil 110. A part of the cooling pipe 150 is located inside the vacuum container 120. The thermal switch unit 160 is located at least in the region between the superconducting coil 110 and the radiation shield 130. The heat switch unit 160 is connected to the superconducting coil 110. The heat switch unit 160 may take a first state and a second state. In the second state, the heat switch unit 160 is configured to be changeable so that the thermal conductivity between the superconducting coil 110 and the cooling pipe 150 is lower than that in the first state.
　これにより、超電導コイル１１０を常温から冷却するときには、熱スイッチ部１６０を第１の状態とすることで、冷凍機１４０と冷却管１５０とによって超電導コイル１１０を冷却して冷却効率を向上させて、冷却時間を短縮することができるとともに、超電導コイル１１０が定常運転状態であるときには、熱スイッチ部１６０を第２の状態とすることで、冷却管１５０を介して超電導コイル１１０に侵入する熱の熱量を低減できる。 As a result, when the superconducting coil 110 is cooled from room temperature, the heat switch unit 160 is set to the first state, so that the superconducting coil 110 is cooled by the refrigerator 140 and the cooling pipe 150 to improve the cooling efficiency. The cooling time can be shortened, and when the superconducting coil 110 is in a steady operation state, the heat switch unit 160 is set to the second state, so that the amount of heat that enters the superconducting coil 110 via the cooling pipe 150 is the amount of heat. Can be reduced.
　なお、実施の形態１に係る超電導マグネット１００は、定常状態から室温と同一の温度を有する状態にまで昇温するときにおいては、熱スイッチ部１６０を第１の状態とすることで昇温時間を短縮することもできる。 When the temperature of the superconducting magnet 100 according to the first embodiment is raised from a steady state to a state having the same temperature as room temperature, the heat switch unit 160 is set to the first state to increase the temperature rise time. It can also be shortened.
　実施の形態１において、熱スイッチ部１６０は、超電導コイル１１０側とは反対側において、輻射シールド１３０を介して冷却管１５０と接している。 In the first embodiment, the heat switch unit 160 is in contact with the cooling pipe 150 via the radiation shield 130 on the side opposite to the superconducting coil 110 side.
　これにより、冷却管１５０が超電導コイル１１０に直接接続されている場合、すなわち、輻射シールド１３０を貫通している場合と比較して、輻射シールド１３０の外側から内側へ侵入する熱の熱量を低減できる。 As a result, the amount of heat that penetrates from the outside to the inside of the radiant shield 130 can be reduced as compared with the case where the cooling pipe 150 is directly connected to the superconducting coil 110, that is, it penetrates the radiant shield 130. ..
　実施の形態１に係る超電導マグネット１００は、定常運転状態において、冷却管１５０の内部の圧力が１気圧以上に維持可能に構成されている。 The superconducting magnet 100 according to the first embodiment is configured so that the pressure inside the cooling pipe 150 can be maintained at 1 atm or more in a steady operation state.
　これにより、空気が冷却管１５０の内部に吸い込まれて空気中の水分が冷却管１５０の内部で氷結することを抑制できる。ひいては、超電導コイル１１０の昇温時において、氷結した水分によって冷却管１５０の内部に位置する冷媒が急激に蒸発することを抑制できる。 As a result, it is possible to prevent air from being sucked into the cooling pipe 150 and freezing of moisture in the air inside the cooling pipe 150. As a result, when the temperature of the superconducting coil 110 is raised, it is possible to prevent the refrigerant located inside the cooling pipe 150 from rapidly evaporating due to the frozen moisture.
　実施の形態１において、冷却管１５０は、第１バルブ１５１と、第２バルブ１５２と、逆止弁１５３とを有している。第１バルブ１５１は、真空容器１２０の外側において、冷却管１５０の一方端側に設けられている。第２バルブ１５２は、真空容器１２０の外側において、冷却管１５０の他方端側に設けられている。逆止弁１５３は、冷却管１５０の一方端側または他方端側に設けられている。 In the first embodiment, the cooling pipe 150 has a first valve 151, a second valve 152, and a check valve 153. The first valve 151 is provided on one end side of the cooling pipe 150 on the outside of the vacuum vessel 120. The second valve 152 is provided on the other end side of the cooling pipe 150 on the outside of the vacuum vessel 120. The check valve 153 is provided on one end side or the other end side of the cooling pipe 150.
　これにより、第１バルブ１５１および第２バルブ１５２を閉状態にすることで、定常状態において、冷却管１５０内に冷媒が位置する状態を維持できる。結果として、定常状態において冷却管１５０を介して超電導コイル１１０に侵入する熱の熱量をより低減できる。 As a result, by closing the first valve 151 and the second valve 152, the state in which the refrigerant is located in the cooling pipe 150 can be maintained in the steady state. As a result, the amount of heat that enters the superconducting coil 110 via the cooling pipe 150 in the steady state can be further reduced.
　実施の形態１において、第１バルブ１５１および第２バルブ１５２の各々には、コントローラ１５４が接続されている。コントローラ１５４は、冷却管１５０に直接接触する輻射シールド１３０または熱スイッチ部１６０の温度の値が閾値より低くなったときに、第１バルブ１５１および第２バルブ１５２の各々を閉状態にすることができるように構成されている。 In the first embodiment, the controller 154 is connected to each of the first valve 151 and the second valve 152. The controller 154 may close each of the first valve 151 and the second valve 152 when the temperature value of the radiation shield 130 or the heat switch unit 160 that directly contacts the cooling pipe 150 becomes lower than the threshold value. It is configured so that it can be done.
　これにより、超電導コイル１１０を室温から冷却する過程において、ある程度超電導コイル１１０が冷却された際には、自動的に第１バルブ１５１および第２バルブ１５２の各々を閉状態にすることで、冷却管１５０を介して超電導コイル１１０に侵入する熱の熱量をより低減できる。 As a result, in the process of cooling the superconducting coil 110 from room temperature, when the superconducting coil 110 is cooled to some extent, each of the first valve 151 and the second valve 152 is automatically closed to form a cooling pipe. The amount of heat that enters the superconducting coil 110 via the 150 can be further reduced.
　実施の形態２．
　以下、実施の形態２に係る超電導マグネットについて説明する。実施の形態２に係る超電導マグネットは、熱スイッチ部の構成のみが、実施の形態１に係る超電導マグネット１００とは異なる。よって、実施の形態１に係る超電導マグネット１００と同様である構成については説明を繰り返さない。 Embodiment 2.
Hereinafter, the superconducting magnet according to the second embodiment will be described. The superconducting magnet according to the second embodiment differs from the superconducting magnet 100 according to the first embodiment only in the configuration of the thermal switch portion. Therefore, the description of the configuration similar to that of the superconducting magnet 100 according to the first embodiment will not be repeated.
　図３は、実施の形態２に係る超電導マグネットの構成を示す断面図である。図４は、実施の形態２に係る超電導マグネットにおける熱スイッチ部を示す断面図である。実施の形態２に係る超電導マグネット２００おいて、熱スイッチ部２６０は、固体式の熱スイッチである。具体的には、本実施の形態において、熱スイッチ部２６０は、炭素繊維強化プラスチック２６１を含んでいる。これにより、温度が低くなるほど熱伝導率が低くなる炭素繊維強化プラスチック２６１によって、熱スイッチ部２６０の第１の状態と第２の状態とを自動的に切り替えることができる。 FIG. 3 is a cross-sectional view showing the configuration of the superconducting magnet according to the second embodiment. FIG. 4 is a cross-sectional view showing a thermal switch portion in the superconducting magnet according to the second embodiment. In the superconducting magnet 200 according to the second embodiment, the heat switch unit 260 is a solid-state heat switch. Specifically, in the present embodiment, the heat switch unit 260 contains carbon fiber reinforced plastic 261. As a result, the carbon fiber reinforced plastic 261 whose thermal conductivity decreases as the temperature decreases can automatically switch between the first state and the second state of the heat switch unit 260.
　本実施の形態において、炭素繊維強化プラスチック２６１は、たとえば、炭素繊維強化プラスチック２６１の温度が５０Ｋ以下である場合は、炭素繊維強化プラスチック２６１の温度が５０Ｋより高く室温以下である場合と比較して、熱伝導率が顕著に低くなる。５０Ｋの炭素繊維強化プラスチック２６１の熱伝導率は、室温の炭素繊維強化プラスチック２６１の熱伝導率のおよそ１０分の１である。すなわち、本実施の形態において、熱スイッチ部２６０の温度の第１の範囲は、たとえば５０Ｋより高く室温以下であり、第２の範囲は５０Ｋ未満と見ることができる。 In the present embodiment, the carbon fiber reinforced plastic 261 is, for example, when the temperature of the carbon fiber reinforced plastic 261 is 50 K or less, as compared with the case where the temperature of the carbon fiber reinforced plastic 261 is higher than 50 K and lower than room temperature. , The thermal conductivity is significantly reduced. The thermal conductivity of 50K carbon fiber reinforced plastic 261 is about 1/10 of the thermal conductivity of carbon fiber reinforced plastic 261 at room temperature. That is, in the present embodiment, the first range of the temperature of the heat switch unit 260 can be seen as, for example, higher than 50K and below room temperature, and the second range is less than 50K.
　本実施の形態においては、熱スイッチ部２６０が上述のような特性を有する炭素繊維強化プラスチック２６１を含んでいるため、特に、超電導コイル１１０に主材料として含まれる銅の比熱が比較的大きくなる室温から５０Ｋまでの温度領域において、冷凍機１４０と冷却管１５０とによる超電導コイル１１０の冷却の冷却効率を向上させることができる。ひいては、上記温度域における超電導コイル１１０の冷却時間をより短縮できる。 In the present embodiment, since the thermal switch unit 260 contains the carbon fiber reinforced plastic 261 having the above-mentioned characteristics, in particular, the room temperature at which the specific heat of copper contained in the superconducting coil 110 as the main material becomes relatively large. In the temperature range from 1 to 50 K, the cooling efficiency of cooling the superconducting coil 110 by the refrigerator 140 and the cooling pipe 150 can be improved. As a result, the cooling time of the superconducting coil 110 in the above temperature range can be further shortened.
　実施の形態２において、熱スイッチ部２６０は、第１伝熱部２６２と、第２伝熱部２６３とをさらに含んでいる。第１伝熱部２６２は、炭素繊維強化プラスチック２６１の超電導コイル１１０側に位置している。第２伝熱部２６３は、炭素繊維強化プラスチック２６１の超電導コイル１１０側とは反対側に位置している。これにより、超電導コイル１１０の昇温時においては、冷却管１５０から熱スイッチ部２６０を通って超電導コイル１１０に達する熱経路において、熱伝導率を向上させて、冷却管１５０による冷却効率を向上させることができる。 In the second embodiment, the heat switch unit 260 further includes a first heat transfer unit 262 and a second heat transfer unit 263. The first heat transfer section 262 is located on the superconducting coil 110 side of the carbon fiber reinforced plastic 261. The second heat transfer section 263 is located on the side opposite to the superconducting coil 110 side of the carbon fiber reinforced plastic 261. As a result, when the temperature of the superconducting coil 110 is raised, the thermal conductivity is improved in the heat path from the cooling tube 150 to the superconducting coil 110 through the heat switch unit 260, and the cooling efficiency by the cooling tube 150 is improved. be able to.
　第１伝熱部２６２および第２伝熱部２６３の各々は、熱伝導率が比較的大きい材料で構成されており、たとえば、銅またはアルミニウムなどで構成されている。また、第１伝熱部２６２および第２伝熱部２６３は加工性の良い材料で構成されていることが好ましい。 Each of the first heat transfer section 262 and the second heat transfer section 263 is made of a material having a relatively large thermal conductivity, for example, copper or aluminum. Further, it is preferable that the first heat transfer section 262 and the second heat transfer section 263 are made of a material having good workability.
　なお、本実施の形態において、炭素繊維強化プラスチック２６１は、複数の炭素繊維２６５を有している。複数の炭素繊維２６５のうちの少なくとも一部は、互いに平行に延在しているが、当該延在方向は特に限定されない。 In the present embodiment, the carbon fiber reinforced plastic 261 has a plurality of carbon fibers 265. At least a part of the plurality of carbon fibers 265 extends in parallel with each other, but the extending direction is not particularly limited.
　実施の形態３．
　以下、実施の形態３に係る超電導マグネットについて説明する。実施の形態３に係る超電導マグネットは、炭素繊維強化プラスチックにおける複数の炭素繊維の構成が、実施の形態２に係る超電導マグネット２００と異なる。よって、実施の形態２に係る超電導マグネット２００と同様である構成については説明を繰り返さない。 Embodiment 3.
Hereinafter, the superconducting magnet according to the third embodiment will be described. The superconducting magnet according to the third embodiment is different from the superconducting magnet 200 according to the second embodiment in the composition of the plurality of carbon fibers in the carbon fiber reinforced plastic. Therefore, the description of the configuration similar to that of the superconducting magnet 200 according to the second embodiment will not be repeated.
　図５は、実施の形態３に係る超電導マグネットにおける熱スイッチ部を示す断面図である。図５に示すように、実施の形態３において、炭素繊維強化プラスチック３６１は、複数の第１炭素繊維３６５Ａと、複数の第２炭素繊維３６５Ｂとを有している。複数の第１炭素繊維３６５Ａは、互いに平行に延在している。複数の第２炭素繊維３６５Ｂの各々は、複数の第１炭素繊維３６５Ａの延在方向に対して直交方向から見て、複数の第１炭素繊維３６５Ａの延在方向に対して直交方向に延在している。複数の第１炭素繊維３６５Ａおよび複数の第２炭素繊維３６５Ｂの各々の延在方向は、熱スイッチ部３６０における超電導コイル１１０側から反対側に向かう方向と交差している。これにより、超電導コイル１１０の昇温時においては、冷却管１５０から熱スイッチ部３６０を通って超電導コイル１１０に達する熱経路において、熱伝導率をさらに向上させて、冷却管１５０による冷却効率を向上させることができる。 FIG. 5 is a cross-sectional view showing a thermal switch portion in the superconducting magnet according to the third embodiment. As shown in FIG. 5, in the third embodiment, the carbon fiber reinforced plastic 361 has a plurality of first carbon fibers 365A and a plurality of second carbon fibers 365B. The plurality of first carbon fibers 365A extend parallel to each other. Each of the plurality of second carbon fibers 365B extends in a direction orthogonal to the extending direction of the plurality of first carbon fibers 365A when viewed from a direction orthogonal to the extending direction of the plurality of first carbon fibers 365A. doing. The extending direction of each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B intersects the direction from the superconducting coil 110 side to the opposite side in the thermal switch portion 360. As a result, when the temperature of the superconducting coil 110 is raised, the thermal conductivity is further improved in the heat path from the cooling tube 150 to the superconducting coil 110 through the heat switch unit 360, and the cooling efficiency by the cooling tube 150 is improved. Can be made to.
　また、より具体的には、上記直交方向から見て、複数の第１炭素繊維３６５Ａおよび複数の第２炭素繊維３６５Ｂの各々の延在方向と、熱スイッチ部３６０における超電導コイル１１０側から反対側に向かう方向とのなす角が、およそ４５度となっている。 More specifically, when viewed from the orthogonal direction, the extending directions of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B and the opposite side from the superconducting coil 110 side in the thermal switch portion 360. The angle between the direction and the direction is about 45 degrees.
　図６は、実施の形態３における炭素繊維強化プラスチックの、第１方向および第２方向の各々の熱伝導率を、炭素繊維強化プラスチックの各温度毎に測定した実験結果の一例を示すグラフである。図６においては、本実施の形態における炭素繊維強化プラスチックについて、上記直交方向から見て、複数の第１炭素繊維３６５Ａおよび複数の第２炭素繊維３６５Ｂの各々の延在方向に対してなす角が４５度となる方向である第１方向における熱伝導率を第１熱伝導率とし、プロット点Ａで示した。また。図６においては、上記直交方向から見て、複数の第１炭素繊維３６５Ａおよび複数の第２炭素繊維３６５Ｂの各々の延在方向に対してなす角が０度または９０度となる方向である第２方向における熱伝導率を第２熱伝導率とし、プロット点Ｂで示した。 FIG. 6 is a graph showing an example of experimental results in which the thermal conductivity of the carbon fiber reinforced plastic in the third embodiment was measured for each temperature of the carbon fiber reinforced plastic in each of the first direction and the second direction. .. In FIG. 6, with respect to the carbon fiber reinforced plastic according to the present embodiment, the angles formed by the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B with respect to the extending directions are formed when viewed from the orthogonal direction. The thermal conductivity in the first direction, which is the direction of 45 degrees, was defined as the first thermal conductivity and is shown at plot point A. Also. In FIG. 6, when viewed from the orthogonal direction, the angle formed by each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B with respect to the extending direction is 0 degree or 90 degrees. The thermal conductivity in the two directions was defined as the second thermal conductivity and is shown at plot point B.
　図６に示すように、炭素繊維強化プラスチックの温度が２０Ｋの場合と比較して、炭素繊維強化プラスチックの温度が室温の場合の第２熱伝導率は８０倍となるのに対して、第１熱伝導率は１３０倍となっている。このように、上記直交方向から見て、本実施の形態における炭素繊維強化プラスチック３６１は、室温近傍の温度領域において、複数の第１炭素繊維３６５Ａおよび複数の第２炭素繊維３６５Ｂの各々の延在方向とのなす角が０度または９０度である第２方向の熱伝導率より、複数の第１炭素繊維３６５Ａおよび複数の第２炭素繊維３６５Ｂの各々の延在方向と交差する方向の熱伝導率が高くなることがわかる。 As shown in FIG. 6, the second thermal conductivity is 80 times higher when the temperature of the carbon fiber reinforced plastic is room temperature as compared with the case where the temperature of the carbon fiber reinforced plastic is 20 K, whereas the first thermal conductivity is 80 times higher. The thermal conductivity is 130 times. As described above, when viewed from the orthogonal direction, the carbon fiber reinforced plastic 361 in the present embodiment has the extension of each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B in the temperature region near room temperature. The heat conductivity in the direction intersecting the extending direction of each of the plurality of first carbon fibers 365A and the plurality of second carbon fibers 365B from the heat conductivity in the second direction in which the angle formed by the direction is 0 degrees or 90 degrees. It can be seen that the rate is high.
　実施の形態４．
　以下、実施の形態４に係る超電導マグネットについて説明する。実施の形態４に係る超電導マグネットは、熱スイッチ部の構成が主に、実施の形態１に係る超電導マグネット１００と異なる。よって、実施の形態１に係る超電導マグネット１００と同様である構成については、説明を繰り返さない。 Embodiment 4.
Hereinafter, the superconducting magnet according to the fourth embodiment will be described. The superconducting magnet according to the fourth embodiment is different from the superconducting magnet 100 according to the first embodiment mainly in the configuration of the thermal switch portion. Therefore, the description of the configuration similar to that of the superconducting magnet 100 according to the first embodiment will not be repeated.
　図７は、実施の形態４に係る超電導マグネットにおける冷却管および熱スイッチ部を示す斜視図である。図７に示すように、実施の形態４において、熱スイッチ部４６０は、超電導コイル１１０側とは反対側において、直接、冷却管１５０と接している。これにより、冷却管１５０が輻射シールド１３０を介して超電導コイル１１０と接続されているのと比較して、冷却管１５０による超電導コイル１１０の冷却効率を向上させることができる。 FIG. 7 is a perspective view showing a cooling tube and a heat switch portion in the superconducting magnet according to the fourth embodiment. As shown in FIG. 7, in the fourth embodiment, the heat switch unit 460 is in direct contact with the cooling pipe 150 on the side opposite to the superconducting coil 110 side. As a result, the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be improved as compared with the case where the cooling pipe 150 is connected to the superconducting coil 110 via the radiation shield 130.
　実施の形態４において、熱スイッチ部４６０は、１または複数の炭素繊維である。これにより、熱伝導率が高い、かつ、熱スイッチとして機能する炭素繊維を直接、冷却管１５０に接続することで、冷却管１５０による超電導コイル１１０の冷却効率をさらに向上させることができる。また、熱スイッチ部４６０を簡易な構成で設けることとができる。 In the fourth embodiment, the heat switch unit 460 is one or more carbon fibers. As a result, the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be further improved by directly connecting the carbon fibers having high thermal conductivity and functioning as a heat switch to the cooling pipe 150. Further, the heat switch unit 460 can be provided with a simple configuration.
　なお、本実施の形態において、炭素繊維は、約５０Ｋ以上から室温以下の温度領域において、約５０Ｋ未満の温度領域と比較して熱伝導率は顕著に高くなる。このため、本実施の形態においても、超電導コイル１１０に主材料として含まれる銅の比熱が比較的大きくなる室温から５０Ｋまでの温度領域において、冷凍機１４０と冷却管１５０とによる超電導コイル１１０の冷却の冷却効率を向上させることができる。ひいては、上記温度域における超電導コイル１１０の冷却時間をより短縮できる。 In the present embodiment, the thermal conductivity of the carbon fiber in the temperature range of about 50 K or more and room temperature or less is significantly higher than that in the temperature range of less than about 50 K. Therefore, also in the present embodiment, the superconducting coil 110 is cooled by the refrigerator 140 and the cooling pipe 150 in the temperature range from room temperature to 50 K where the specific heat of copper contained in the superconducting coil 110 as a main material is relatively large. Cooling efficiency can be improved. As a result, the cooling time of the superconducting coil 110 in the above temperature range can be further shortened.
　実施の形態４において、熱スイッチ部４６０は、冷却管１５０に巻き付けられた状態で冷却管１５０と接している。これにより、熱スイッチ部４６０と冷却管１５０との接触面積が大きくなり、冷却管１５０による超電導コイル１１０の冷却効率を大幅に向上させることができる。 In the fourth embodiment, the heat switch unit 460 is in contact with the cooling pipe 150 in a state of being wound around the cooling pipe 150. As a result, the contact area between the heat switch portion 460 and the cooling pipe 150 becomes large, and the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be significantly improved.
　実施の形態４において、熱スイッチ部４６０として冷却管１５０に巻き付けられた複数の炭素繊維の各々の巻回数は、１回でもよいし、複数回でもよい。炭素繊維の少なくとも一方端は、たとえば、超電導線を包囲するように設けられた図示しない熱伝導部材または当該熱伝導部材上に設けられた図示しない他の熱伝導部材を介して、超電導コイル１１０に接続される。 In the fourth embodiment, the number of times each of the plurality of carbon fibers wound around the cooling pipe 150 as the heat switch unit 460 may be one or a plurality of times. At least one end of the carbon fiber is attached to the superconducting coil 110 via, for example, a heat conductive member (not shown) provided so as to surround the superconducting wire or another heat conductive member (not shown) provided on the heat conductive member. Be connected.
　実施の形態５．
　以下、実施の形態５に係る超電導マグネットについて説明する。実施の形態５に係る超電導マグネットは、熱スイッチ部の構成が主に、実施の形態４に係る超電導マグネットと異なる。よって、実施の形態４に係る超電導マグネットと同様である構成については、説明を繰り返さない。 Embodiment 5.
Hereinafter, the superconducting magnet according to the fifth embodiment will be described. The superconducting magnet according to the fifth embodiment is different from the superconducting magnet according to the fourth embodiment mainly in the configuration of the thermal switch portion. Therefore, the description of the configuration similar to that of the superconducting magnet according to the fourth embodiment will not be repeated.
　図８は、実施の形態５に係る超電導マグネットにおける冷却管および熱スイッチ部を示す斜視図である。図８に示すように、実施の形態５において、熱スイッチ部５６０は、１または複数のシート状の炭素繊維強化プラスチックである。これにより、熱スイッチ部５６０を冷却管１５０に巻き付けることができる。 FIG. 8 is a perspective view showing a cooling tube and a heat switch portion in the superconducting magnet according to the fifth embodiment. As shown in FIG. 8, in the fifth embodiment, the heat switch unit 560 is one or a plurality of sheet-shaped carbon fiber reinforced plastics. As a result, the heat switch unit 560 can be wound around the cooling pipe 150.
　さらに、複数のシート状の炭素繊維強化プラスチックである熱スイッチ部５６０の各々は冷却管１５０に巻き付けられている。これにより、熱スイッチ部５６０と冷却管１５０との接触面積を大きくすることができ、冷却管１５０による超電導コイル１１０の冷却効率をさらに向上させることができる。 Further, each of the heat switch portions 560, which are a plurality of sheet-shaped carbon fiber reinforced plastics, is wound around the cooling pipe 150. As a result, the contact area between the heat switch portion 560 and the cooling pipe 150 can be increased, and the cooling efficiency of the superconducting coil 110 by the cooling pipe 150 can be further improved.
　複数のシート状の炭素繊維強化プラスチックの各々は、冷却管１５０に対して、接着材を介して固定されていてもよいし、ボルト締めによる固定されていてもよい。 Each of the plurality of sheet-shaped carbon fiber reinforced plastics may be fixed to the cooling pipe 150 via an adhesive, or may be fixed by bolting.
　上述した実施の形態の説明において、組み合わせ可能な構成を相互に組み合わせてもよい。 In the above description of the embodiment, the configurations that can be combined may be combined with each other.
　なお、今回開示した上記実施の形態はすべての点で例示であって、限定的な解釈の根拠となるものではない。したがって、本開示の範囲は、上記した実施の形態のみによって解釈されるものではなく、請求の範囲の記載に基づいて画定される。また、請求の範囲と均等の意味および範囲内でのすべての変更が含まれる。 It should be noted that the above-described embodiment disclosed this time is an example in all respects and does not serve as a basis for a limited interpretation. Therefore, the scope of the present disclosure is not construed solely by the embodiments described above, but is defined based on the statements of the claims. It also includes all changes within the meaning and scope of the claims.
　１００，２００　超電導マグネット、１１０　超電導コイル、１２０　真空容器、１３０　輻射シールド、１４０　冷凍機、１４１　第１ステージ、１４２　第２ステージ、１５０　冷却管、１５１　第１バルブ、１５２　第２バルブ、１５３　逆止弁、１５４　コントローラ、１６０，２６０，３６０，４６０，５６０　熱スイッチ部、２６１，３６１　炭素繊維強化プラスチック、２６２　第１伝熱部、２６３　第２伝熱部、２６５　炭素繊維、３６５Ａ　第１炭素繊維、３６５Ｂ　第２炭素繊維。 100, 200 superconducting magnet, 110 superconducting coil, 120 vacuum vessel, 130 radiation shield, 140 refrigerator, 141 first stage, 142 second stage, 150 cooling pipe, 151 first valve, 152 second valve, 153 check valve , 154 controller, 160, 260, 360, 460, 560 heat switch part, 261 and 361 carbon fiber reinforced plastic, 262 first heat transfer part, 263 second heat transfer part, 265 carbon fiber, 365A first carbon fiber, 365B Second carbon fiber.

Claims (12)

  1. 　超電導コイルと、
    　前記超電導コイルを収容する真空容器と、
    　前記超電導コイルと前記真空容器との間に配置され、前記超電導コイルの周りを囲む輻射シールドと、
    　第１ステージおよび第２ステージを含み、前記真空容器の外側から前記超電導コイルに接続された冷凍機と、
    　冷却媒体が通流可能であって、前記真空容器の外側から前記超電導コイルに向かって延び、かつ、前記真空容器の内部に一部が位置している冷却管と、
    　少なくとも前記超電導コイルと前記輻射シールドとの間の領域に位置して、前記超電導コイルに接続された熱スイッチ部とを備え、
    　前記第１ステージは、前記輻射シールドと接続されており、
    　前記第２ステージは、前記超電導コイルと接続されており、
    　前記熱スイッチ部は、第１の状態と第２の状態とをとり得り、
    　前記熱スイッチ部は、前記第２の状態においては、前記第１の状態と比較して、前記超電導コイルと前記冷却管との間の熱伝導率が低くなるように変更可能に構成されている、超電導マグネット。     Superconducting coil and
    A vacuum container accommodating the superconducting coil and
    A radiation shield arranged between the superconducting coil and the vacuum vessel and surrounding the superconducting coil,
    A refrigerator including the first stage and the second stage, which is connected to the superconducting coil from the outside of the vacuum vessel, and
    A cooling tube through which the cooling medium can flow, extending from the outside of the vacuum vessel toward the superconducting coil, and partially located inside the vacuum vessel.
    A thermal switch section located at least in the region between the superconducting coil and the radiation shield and connected to the superconducting coil is provided.
    The first stage is connected to the radiation shield and
    The second stage is connected to the superconducting coil and is connected to the superconducting coil.
    The heat switch unit can take a first state and a second state.
    The heat switch unit is configured to be changeable so that the thermal conductivity between the superconducting coil and the cooling pipe is lower in the second state than in the first state. , Superconducting magnet.
  2. 　前記熱スイッチ部は、超電導コイル側とは反対側において、直接、前記冷却管と接している、請求項１に記載の超電導マグネット。 The superconducting magnet according to claim 1, wherein the heat switch unit is in direct contact with the cooling pipe on a side opposite to the superconducting coil side.
  3. 　前記熱スイッチ部は、超電導コイル側とは反対側において、前記輻射シールドを介して前記冷却管と接している、請求項１に記載の超電導マグネット。 The superconducting magnet according to claim 1, wherein the heat switch portion is in contact with the cooling tube via the radiation shield on the side opposite to the superconducting coil side.
  4. 　前記熱スイッチ部は、炭素繊維強化プラスチックを含む、請求項１から請求項３のいずれか１項に記載の超電導マグネット。 The superconducting magnet according to any one of claims 1 to 3, wherein the heat switch unit contains carbon fiber reinforced plastic.
  5. 　前記炭素繊維強化プラスチックは、互いに平行に延在する複数の第１炭素繊維と、該複数の第１炭素繊維の延在方向に対して直交方向から見て、前記複数の第１炭素繊維の延在方向に対して直交方向に延在する複数の第２炭素繊維とを有し、
    　前記複数の第１炭素繊維および前記複数の第２炭素繊維の各々の延在方向は、前記熱スイッチ部における超電導コイル側から反対側に向かう方向と交差している、請求項４に記載の超電導マグネット。     The carbon fiber reinforced plastic includes a plurality of first carbon fibers extending in parallel with each other and a spread of the plurality of first carbon fibers when viewed from a direction orthogonal to the extending direction of the plurality of first carbon fibers. It has a plurality of secondary carbon fibers extending in a direction orthogonal to the existing direction, and has a plurality of secondary carbon fibers.
    The superconducting direction according to claim 4, wherein the extending directions of the plurality of first carbon fibers and the plurality of second carbon fibers intersect with the direction from the superconducting coil side to the opposite side in the thermal switch portion. magnet.
  6. 　前記熱スイッチ部は、前記炭素繊維強化プラスチックの超電導コイル側に位置する第１伝熱部と、前記炭素繊維強化プラスチックの超電導コイル側とは反対側に位置する第２伝熱部とをさらに含む、請求項４または請求項５に記載の超電導マグネット。 The heat switch section further includes a first heat transfer section located on the superconducting coil side of the carbon fiber reinforced plastic and a second heat transfer section located on the side opposite to the superconducting coil side of the carbon fiber reinforced plastic. , The superconducting magnet according to claim 4 or 5.
  7. 　前記熱スイッチ部は複数の炭素繊維である、請求項１または請求項２に記載の超電導マグネット。 The superconducting magnet according to claim 1 or 2, wherein the heat switch unit is a plurality of carbon fibers.
  8. 　前記熱スイッチ部は、複数のシート状の炭素繊維強化プラスチックである、請求項１または請求項２に記載の超電導マグネット。 The superconducting magnet according to claim 1 or 2, wherein the heat switch portion is a plurality of sheet-shaped carbon fiber reinforced plastics.
  9. 　前記熱スイッチ部は、前記冷却管に巻き付けられた状態で前記冷却管と接している、請求項７または請求項８に記載の超電導マグネット。 The superconducting magnet according to claim 7 or 8, wherein the heat switch unit is in contact with the cooling pipe in a state of being wound around the cooling pipe.
  10. 　定常運転状態において、前記冷却管の内部の圧力が１気圧以上に維持可能に構成されている、請求項１から請求項９のいずれか１項に記載の超電導マグネット。 The superconducting magnet according to any one of claims 1 to 9, wherein the pressure inside the cooling pipe can be maintained at 1 atm or more in a steady operation state.
  11. 　前記冷却管は、前記真空容器の外側において、一方端側に設けられた第１バルブと、他方端側に設けられた第２バルブと、前記一方端側または前記他方端側に設けられた逆止弁とを有する、請求項１０に記載の超電導マグネット。 The cooling pipe is provided on the outside of the vacuum vessel, with a first valve provided on one end side, a second valve provided on the other end side, and a reverse valve provided on the one end side or the other end side. The superconducting magnet according to claim 10, further comprising a check valve.
  12. 　前記第１バルブおよび前記第２バルブの各々には、前記冷却管に直接接触する前記輻射シールドまたは前記熱スイッチ部の温度の値が閾値より低くなったときに、前記第１バルブおよび前記第２バルブの各々を閉状態にすることができるように構成されたコントローラが接続されている、請求項１１に記載の超電導マグネット。 The first valve and the second valve are attached to the first valve and the second valve, respectively, when the temperature value of the radiation shield or the heat switch portion that directly contacts the cooling pipe becomes lower than the threshold value. The superconducting magnet according to claim 11, to which a controller configured to allow each of the valves to be closed is connected.
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