WO2018003420A1 - Dispositif magnétique supraconducteur et dispositif d'imagerie tomographique par résonance magnétique - Google Patents

Dispositif magnétique supraconducteur et dispositif d'imagerie tomographique par résonance magnétique Download PDF

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Publication number
WO2018003420A1
WO2018003420A1 PCT/JP2017/020897 JP2017020897W WO2018003420A1 WO 2018003420 A1 WO2018003420 A1 WO 2018003420A1 JP 2017020897 W JP2017020897 W JP 2017020897W WO 2018003420 A1 WO2018003420 A1 WO 2018003420A1
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refrigerant
superconducting magnet
circulation
magnet device
superconducting
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PCT/JP2017/020897
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English (en)
Japanese (ja)
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学 青木
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株式会社日立製作所
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00Superconducting magnets; Superconducting coils
    • H01F6/04Cooling
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00Superconducting devices
    • H10N60/30Devices switchable between superconducting and normal states
    • H10N60/35Cryotrons
    • H10N60/355Power cryotrons
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00Superconducting devices
    • H10N60/80Constructional details
    • H10N60/81Containers; Mountings

Definitions

  • the present invention relates to a superconducting magnet apparatus and a magnetic resonance tomography apparatus.
  • the superconducting magnet device is composed of a superconducting coil and a permanent current switch installed in parallel thereto, and the above-described permanent current switch is heated to a normal conduction state by generating a resistance (hereinafter referred to as an open state). ), The current is supplied from the exciting power source to the superconducting coil, and then the permanent current switch is cooled to be in the superconducting state (hereinafter referred to as the closed state).
  • This is a permanent current operation in which a current continues to flow in a superconducting closed circuit composed of a permanent current switch with almost no attenuation. As a result, the superconducting magnet device can maintain the magnetic field for a long time.
  • a conventional superconducting magnet device is a submerged cooling system that is used by immersing it in a refrigerant typified by liquid helium or liquid nitrogen in order to keep the constituent elements typified by the superconducting coil and the permanent current switch in a superconducting state, and Many conductive cooling systems are employed in which a refrigerator and a component are thermally connected with a metal having good thermal conductivity to cool.
  • a refrigerant typified by liquid helium or liquid nitrogen
  • Many conductive cooling systems are employed in which a refrigerator and a component are thermally connected with a metal having good thermal conductivity to cool.
  • a refrigerant circulation type cooling system has been studied, and a large apparatus represented by a fusion apparatus employs a forced cooling system in which a refrigerant flow path is provided inside the apparatus and forcedly circulated by a pump (for example, a patent).
  • a pump for example, a patent.
  • Reference 1 In a medium-sized apparatus typified by a magnetic resonance tomography apparatus (MRI), the refrigerant is flown in the flow path by using buoyancy due to the density difference between the refrigerant vaporized by a heat source such as a superconducting coil and the refrigerant liquefied by a refrigerator.
  • MRI magnetic resonance tomography apparatus
  • a loop-type thermosiphon system for natural circulation has been proposed (for example, Patent Documents 2 and 3).
  • the refrigerant circulation type cooling method is expected to shorten the time required to open and close the permanent current switch compared to the conduction cooling method.
  • the permanent current switch is heated from the closed state to the open state, it is difficult to actively control the circulation of the refrigerant and immediately stop the cooling. It is necessary to continue heater heating with an output exceeding the cooling capacity.
  • an object of the present invention is to provide a superconducting magnet apparatus and a magnetic resonance tomography apparatus capable of reducing the amount of refrigerant vaporized by heater heating in a superconducting magnet apparatus adopting a refrigerant circulation type cooling system.
  • a superconducting coil, a permanent current switch connected to the superconducting coil, the superconducting coil, and the permanent current switch are cooled.
  • a superconducting magnet device having at least a refrigerant circulation type cooling means for circulating the refrigerant in the flow path, wherein the cooling means stores at least a refrigerant container for storing the liquefied refrigerant, and a refrigerant circulation for circulating the refrigerant.
  • Examples include a superconducting magnet device having stop means for stopping circulation of the refrigerant flowing through the refrigerant circulation passage in the section to the arrangement location.
  • a superconducting magnet apparatus and a magnetic resonance tomography apparatus capable of reducing the amount of refrigerant vaporized by heating a heater in a superconducting magnet apparatus adopting a refrigerant circulation type cooling system.
  • FIG. 2 is a bird's eye view of the superconducting magnet device 1 shown in FIG. 1 in which only the refrigerant circulation channel 6 and the refrigerant container 8 are extracted and illustrated. Sectional drawing of the superconducting magnet apparatus 1 which concerns on 2nd Embodiment is shown.
  • FIG. 5 is a bird's-eye view showing only the refrigerant circulation flow path 6 and the refrigerant container 8 with respect to the superconducting magnet device 1 shown in FIG. 4.
  • FIG. 7 is a cross-sectional view of the superconducting magnet device 1 shown in FIG. 6 taken along the line AA.
  • FIG. 7 is a BB sectional view of the superconducting magnet device 1 shown in FIG.
  • FIG. 7 is a bird's-eye view showing only the refrigerant circulation flow path 6, the refrigerant container 8, and the permanent current switch 9 of the superconducting magnet device 1 shown in FIG. 6.
  • Sectional drawing of the superconducting magnet apparatus which concerns on 5th Embodiment is shown.
  • 1 is a schematic diagram of a magnetic resonance imaging apparatus.
  • FIG. 1 schematically shows a cross section of a superconducting magnet device 1 according to the first embodiment.
  • the superconducting magnet device 1 includes a vacuum vessel 2, a radiation shield 3 contained in the vacuum vessel 2, a plurality of superconducting coils 4 contained in the radiation shield 3, a coil bobbin 5 to which the superconducting coil 4 is fixed, a refrigerant circulation channel 6,
  • the basic configuration includes a refrigerant 7 contained in the refrigerant circulation channel 6, a refrigerant container 8 storing the refrigerant 7, a permanent current switch 9, and a refrigerator 12 attached to the refrigerant container 8.
  • the refrigerant 7 for example, liquid helium or liquid nitrogen can be used.
  • the shape of the vacuum vessel 2 and the radiation shield 3 shown in FIG. 1 can take any shape as long as the support structure and the constituent members constituting the superconducting magnet device 1 are allowed.
  • the central axis 21 of the superconducting coil 4 of the present embodiment is oriented in the vertical direction.
  • the central axis 21 is the winding central axis of the superconducting coil 4 and coincides with the direction of the magnetic field generated when the superconducting coil 4 is energized.
  • the refrigerant circulation channel 6 has a structure in which the superconducting coil 4 and the coil bobbin 5 are thermally contacted and cooled via a heat conduction path 11 which is a heat transfer member. Therefore, the heat conduction path 11 is composed of a good conductor having high heat conductivity, and specifically, a copper mesh wire or the like is used. Further, the permanent current switch 9 is also cooled by the refrigerant circulation passage 6 in the same manner as the superconducting coil 4.
  • the refrigerant circulation channel 6 and the heat conduction path 11 mainly constitute the cooling means of this embodiment.
  • FIG. 2 schematically shows the superconducting magnet device 1 as a circuit.
  • the protective resistors 10 are provided in the same number as the number of superconducting coils 4 installed, and each protective resistor 10 is installed in parallel to each superconducting coil 4.
  • a DC power source 13 and a current breaker 14 that are current sources for exciting the superconducting coil 4 are installed outside the vacuum vessel 2.
  • a superconducting coil 4 and a permanent current switch 9 are installed inside the vacuum vessel 2 and are kept below the critical temperature and are in a superconducting state.
  • the procedure for generating a permanent current is as follows. First, current is supplied from the DC power supply 13 to the superconducting coil 4 with the permanent current switch 9 opened. Thereafter, with the permanent current switch 9 closed, the supply current from the DC power supply 13 is made zero and the current breaker 14 is opened. As a result, the operation is a permanent current operation in which the current continues to flow in the superconducting closed circuit composed of the superconducting coil 4 and the permanent current switch 9 with almost no attenuation. Thereby, the superconducting magnet apparatus 1 can hold a magnetic field for a long time. When the permanent current switch 9 is opened, it means that the permanent current switch 9 is changed to a normal conduction state and an electric resistance is generated. Moreover, the permanent current switch 9 is closed by shifting the permanent current switch 9 to the superconducting state and setting the electrical resistance to a very low state.
  • FIG. 3 shows a bird's-eye view of the refrigerant flow path in the superconducting magnet device 1 with respect to the superconducting magnet device 1 shown in FIG.
  • the refrigerant circulation path and the mechanism by which the refrigerant 7 circulates along the path will be described as follows.
  • the refrigerant circulation channel 6 is connected to the refrigerant circulation part 6d that is in thermal contact with the permanent current switch 9, the refrigerant circulation part 6e that is in thermal contact with the superconducting coil 4, the refrigerant circulation part 6d, and the refrigerant container 8. It is comprised from the part 6c (6a and 6b).
  • the refrigerant 7 flowing through the refrigerant circulation parts 6d and 6e has a lower density per unit volume than the refrigerant 7 in the refrigerant container 8 and the refrigerant circulation part 6c. Buoyancy is generated by this density difference, and the refrigerant 7 moves along the refrigerant circulation passage 6 with a force from the bottom to the top in the vertical direction.
  • the reason why the density of the refrigerant 7 flowing through the refrigerant circulation parts 6d and 6e is reduced is that the refrigerant 7 thermally absorbs heat from these heat sources because it is thermally connected to the permanent current switch 9 and the superconducting coil 4. This is because the volume per unit mass increases.
  • Reference numeral 20 in the figure indicates the circulation direction of the refrigerant 7 described above.
  • the loop thermosyphon is a refrigerant circulation system that utilizes the density difference of the refrigerant 7 generated in the refrigerant circulation section, there is an advantage that a pump or the like for circulating the refrigerant 7 is unnecessary. Further, since the amount of the refrigerant 7 used is sufficient to create a flow that circulates through the refrigerant container 8 and the refrigerant circulation passage 6, the cooling state is maintained even if the amount of the refrigerant 7 used is small compared to the immersion cooling method. Can be maintained.
  • the cooling means is not a loop thermosyphon type but a forced circulation type, a time lag occurs until the refrigerant circulation stops even if the pump used for circulation stops. Therefore, similarly to the loop thermosiphon type cooling, it is necessary to continue heating the heater for a certain period of time so that the permanent current switch 9 maintains a critical temperature or higher.
  • the superconducting magnet device 1 of the present embodiment discharges or shields the refrigerant 7 flowing through the refrigerant circulation channel 6 in the section from the refrigerant container 8 to the arrangement position of the heat conduction path 11 in contact with the permanent current switch 9. Stop means for stopping the circulation of the refrigerant 7 is provided. A specific concept of this stopping means will be described below. In the following description, the case of adopting the loop thermosiphon type is taken as an example, but the same applies to the forced circulation type.
  • the superconducting magnet device 1 of the present embodiment has a structure shown in FIGS. 1 and 3 as a stopping means for stopping the circulation of the refrigerant 7.
  • These structures are mainly composed of the refrigerant circulation section 6c, the heater 52 as circulation suppression means, the branch pipe 6f, and the opening / closing means of the branch pipe 6f.
  • the refrigerant circulation portion 6 c is a meandering portion that is provided in a part of the refrigerant circulation passage 6 and that is vertically related to the vertical direction. As shown in FIG. 3, it is comprised from the refrigerant
  • the refrigerant circulation unit 6 a is a pipe that is connected to the vicinity of the bottom of the refrigerant container 8 and that extends upward from the vicinity of the bottom of the refrigerant container 8.
  • coolant circulation part 6b is piping which goes below from the upper end part of the refrigerant
  • the refrigerant storage unit 15 is provided at each end, and the upper end of the refrigerant circulation unit 6a and the upper end of the refrigerant circulation unit 6b are connected to the refrigerant storage unit 15. Structure. Specifically, as illustrated in FIG. 1, the refrigerant storage unit 15 is provided at the upper and lower folding position of the refrigerant circulation unit 6 c.
  • coolant storage part 15 may use a container different from piping as the refrigerant
  • the refrigerant storage unit 15 When the refrigerant storage unit 15 is made of a material different from that of the refrigerant circulation unit, it is desirable that the refrigerant storage unit 15 be made of a material having higher thermal conductivity than the refrigerant circulation unit.
  • the refrigerant reservoir 15 is heated by the heater 51 when the permanent current switch 9 is opened, and the internal refrigerant 7 needs to be quickly evaporated. Therefore, it is desirable to be made of copper or aluminum.
  • coolant storage part 15 are comprised with a material with low heat conductivity, for example, stainless steel.
  • the refrigerant reservoir 15 is installed in a vertical direction so as to be lower than the liquid level of the refrigerant 7 accommodated in the refrigerant container 8. This is because the refrigerant 7 filled in the refrigerant reservoir 15 rises and flows in the refrigerant circulation unit 6 a against gravity due to the dead weight of the refrigerant 7 accommodated in the refrigerant container 8.
  • the heater 51 is provided at least in the vicinity of the meandering portion, and prevents the refrigerant 7 from circulating by evaporating the refrigerant 7 flowing through the refrigerant circulation portion 6c.
  • the attachment position of the heater 51 is set to the refrigerant
  • the heater 51 operates at the same timing as the heater 52 that heats the permanent current switch 9. Therefore, by sharing the power source and the conductive wire with the heater 52, the heating timing can be easily synchronized, and the structure can be simplified.
  • the heater 51 is a general electric heater, and for example, a nichrome wire heater can be used.
  • the branch pipe 6 f is a pipe that reaches the outside of the vacuum vessel 2 and that discharges the refrigerant 7 evaporated by the operation of the heater 51.
  • a pressure sensor or a temperature sensor may be attached to the branch pipe 6f as means for detecting the liquid level of the refrigerant 7.
  • the liquid level position (the liquid level position in the rated state) of the refrigerant 7 is approximately the same between the refrigerant container 8 and the branch pipe 6f. Detecting the liquid level of the refrigerant 7 in the branch pipe 6f has the following advantages.
  • the superconducting magnet device 1 of this embodiment employs a loop thermosyphon cooling system. For this reason, when bubbles accumulate in the refrigerant circulation channel 6 and the refrigerant reservoir 15, the buoyancy derived from the density difference that is the source of the conveying force of the refrigerant 7 is not efficiently transmitted, and the circulation of the refrigerant 7 stops or the efficiency decreases. There is a possibility that.
  • the meandering part constituted by the refrigerant circulation part 6c and the refrigerant storage part 15 of the present embodiment has no heat source under a permanent current operation.
  • the refrigerant 7 is conveyed by the pressure generated from the difference between the density of the refrigerant 7 in the refrigerant container 8 and the density of the refrigerant 7 in the refrigerant circulation unit 6d. Therefore, in order to efficiently circulate the refrigerant 7, it is desirable to suppress a decrease in the circulation efficiency of the refrigerant 7 in the meandering portion, and to detect it immediately when a decrease in efficiency occurs. Therefore, a means for detecting the liquid level position of the refrigerant 7 and a means for estimating the storage state of the refrigerant 7 may be provided in the branch pipe 6f.
  • the means for controlling the opening and closing of the branch pipe 6f is, for example, a valve 61 as shown in FIG.
  • the valve 61 is provided outside the vacuum vessel 2 and may be operated either manually or automatically.
  • the heater 51 is operated to evaporate the refrigerant 7.
  • the valve 61 is opened, the vaporized refrigerant 7 is discharged to the outside. This discharge can prevent an excessive pressure from being applied to the meandering portion and stop the circulation of the refrigerant 7. Further, as shown in FIG.
  • a configuration may be employed in which a flow path returning from the branch pipe 6f to the refrigerant container 8 is provided and the refrigerant gas generated in the branch pipe 6f is liquefied again and used.
  • the flow path returning to the refrigerant container 8 the consumption amount of the refrigerant 7 can be further reduced.
  • the permanent current switch 9 is opened and closed as follows.
  • the heater 51 When switching the permanent current switch 9 from the closed state to the open state, the heater 51 is energized with the valves 61 and 62 closed.
  • the refrigerant 7 circulating through the meandering portion is vaporized by the heater 51.
  • the vaporized refrigerant 7 or the refrigerant 7 whose density has decreased due to the temperature rise obtains buoyancy and stays in the refrigerant reservoir 15.
  • the accumulated refrigerant 7 hinders the circulation of the refrigerant 7 in the meandering portion, and the circulation of the refrigerant 7 toward the permanent current switch 9 is stopped.
  • the heater 52 is energized in conjunction with the energization of the heater 51, the refrigerant 7 in the refrigerant circulation section 6d that is in thermal contact with the permanent current switch 9 vaporizes or rises in temperature, and the resulting buoyancy causes the refrigerant 7 Returns to the refrigerant container 8.
  • the permanent current switch 9 and the refrigerant 7 existing in the refrigerant circulation part 6d evaporate, and the liquid level rapidly decreases.
  • the liquid level is lower than the permanent current switch 9, in other words, the position where the liquid level of the refrigerant 7 liquefied at the liquid level is in direct or indirect thermal contact with the permanent current switch 9.
  • the energization to the heater 51 and the heater 52 may be stopped.
  • the cooling rate of the permanent current switch 9 via the refrigerant circulation portion 6d is lower than the rated state, and the cooling of the permanent current switch 9 by the liquefied refrigerant 7 is suppressed, so the heater This is because the permanent current switch 9 can be kept open without continuing heating by energization.
  • energization of the heater 52 may be continued even after the liquid level of the refrigerant 7 has sufficiently decreased. By continuing the energization, the temperature of the permanent current switch 9 can also rise quickly and shift to the open state.
  • the part of the permanent current switch 9 and the heated refrigerant circulation portion 6 d are arranged so as to be substantially in the same position in the vertical direction. With such an arrangement relationship, both structures can be heated together by one heater 52, and the configuration is simplified.
  • a heater is provided at each attachment position. Also good.
  • the thermal connection position of the permanent current switch 9 to the refrigerant circulation part 6d and the installation position of the refrigerant storage part 15 are lower than the liquid level height of the refrigerant container 8 and the liquid level height. It is desirable to be in the vicinity.
  • the liquid level of the refrigerant container 8, the branch pipe 6f, and the refrigerant circulation part 6d is substantially equal, and exists in the branch pipe 6f and the refrigerant circulation part 6d when the circulation of the refrigerant 7 is stopped. It is necessary to evaporate and remove the refrigerant 7.
  • connection position and the installation position described above at a position close to the liquid level of the refrigerant container 8, the amount of the refrigerant 7 to be evaporated can be reduced, and the liquid level of the refrigerant 7 can be quickly reduced to circulate the refrigerant 7. Can be stopped.
  • the connecting portion between the branch pipe 6f and the refrigerant container 8 is set to a position higher than the liquid level of the refrigerant 7 in the refrigerant container 8. At this position, it is possible to prevent the refrigerant 7 from flowing back into the branch pipe 6f due to gravity.
  • the branch pipe 6f employs a material having a low thermal conductivity such as stainless steel, thereby suppressing the heat conduction through the branch pipe 6f other than the heating portion, thereby the permanent current switch 9 is cooled and closed. Can be avoided.
  • the refrigerant circulation part 6d may be made of two materials.
  • the part where the heater 52 is installed is made of a high heat conductive member such as aluminum, and the other part is made of stainless steel so that they are joined by a dissimilar material joint.
  • the case where a loop-type thermosiphon-type cooling method is employed has been described.
  • the permanent current switch 9 is shifted from the closed state to the open state according to the same procedure as described above after stopping the pump or the like.
  • the circulation of the refrigerant 7 with respect to the superconducting coil 4 is stopped. Therefore, the cooling of the superconducting coil 4 may be continued using cooling or conduction cooling using heat storage of the solid refrigerant together.
  • a plurality of independent refrigerant containers 8 may be provided, and the circulation of the refrigerant 7 for cooling the superconducting coil 4 and the circulation of the refrigerant 7 for cooling the permanent current switch 9 may be separated.
  • the permanent current switch 9 is shifted from the closed state to the open state.
  • the following procedure is executed. First, the valve 61 shown in FIG. 1 is opened, and the low-density refrigerant 7 staying in the refrigerant reservoir 15 is discharged out of the superconducting magnet device 1.
  • a check valve 71 is provided between the discharge side end of the branch pipe 6f and the valve 61 so that the atmosphere does not flow through the branch pipe 6f.
  • the refrigerant 7 passes from the refrigerant container 8 through the refrigerant circulation unit 6a. It flows into the refrigerant reservoir 15.
  • the refrigerant circulation unit 6c basically has no heat source, so that the refrigerant 7 maintains the same density as the state stored in the refrigerant container 8. The refrigerant flows into the refrigerant circulation section 6d as it is.
  • the permanent current switch 9 serves as a heat source for the refrigerant circulation section 6d, the density difference of the refrigerant 7 is caused thereby, and the circulation of the refrigerant 7 is resumed.
  • the permanent liquid switch 9 starts to be cooled when the liquid level inside the refrigerant circulation section 6d rises and is held above the position where it is in thermal contact with the permanent current switch 9. Note that when the permanent current switch 9 is kept closed, it is difficult to completely eliminate the influence of radiant heat or the like, although the refrigerant circulation portion 6c basically has no heat source.
  • the refrigerant 7 vaporized by the heat entering the refrigerant circulation parts 6 a and 6 b without being shielded stays in the refrigerant storage part 15, thereby preventing refrigerant circulation.
  • valve 61 is closed and the valve 62 is opened so that the vaporized refrigerant 7 returns to the refrigerant container 8 through the refrigerant circulation portion 6g.
  • the refrigerant circulation unit 6g can be used as a flow path for supplying the refrigerant 7 to the refrigerant container 8 in a preparation stage in which the superconducting magnet device 1 is operated.
  • a check valve 72 is provided in order to prevent atmospheric inflow, similarly to the atmospheric end of the branch pipe 6f.
  • the pump or the like may be restarted after discharging the gaseous refrigerant 7 retained in the refrigerant reservoir 15 as described above.
  • the superconducting magnet device 1 of the present embodiment can quickly open and close the permanent current switch 9 by partially stopping the circulation of the refrigerant in the refrigerant circulation type superconducting magnet device.
  • coolant circulation part 6c provided with the meandering part are included and partial circulation stop can be performed by the selective heating of this part, the quantity of the refrigerant
  • the heater heating time of the permanent current switch 9 can be reduced as compared with the prior art, and the waiting time for excitation and demagnetization of the superconducting magnet device can be shortened.
  • in the loop thermosyphon since it is possible to actively control the refrigerant circulation, it is possible to achieve a remarkable effect that the time required for opening and closing the permanent current switch 9 is equivalent to that of immersion cooling.
  • FIG. 4 shows a cross-sectional view of the superconducting magnet device 1 according to the second embodiment.
  • FIG. 5 is a bird's-eye view showing only the refrigerant circulation channel 6 and the refrigerant container 8 taken out.
  • the second embodiment further includes a branch pipe 6 f that leads the refrigerant 7 to the outside of the superconducting magnet device 1, and a gas cylinder 81 that is a gas refrigerant introduction unit is provided.
  • the vaporized refrigerant 7 can be supplied from the gas cylinder 81 to the refrigerant reservoir 15.
  • the stop means for stopping the circulation of the refrigerant 7 in this embodiment is mainly composed of the refrigerant circulation portion 6c, a gas cylinder 81 which is a circulation suppression means, and a branch pipe 6f. Moreover, you may add the refrigerant
  • the operation of moving the permanent current switch 9 from the closed state to the open state is performed as follows. First, the valve 61 and the valve 62 are closed, and then the valve 63 is opened. After the valve 63 is opened, the gaseous refrigerant 7 is introduced from the gas cylinder 81 into the branch pipe 6f. The introduced gaseous refrigerant 7 generates a pressure that pushes down the liquid level of the refrigerant 7 below the branch pipe 6f because the valve 61 and the valve 62 are closed.
  • the valve 63 is closed, and then the valve 61 is opened.
  • the gaseous refrigerant 7 accommodated in the branch pipe 6 f and the refrigerant reservoir 15 is discharged through the valve 61.
  • the discharge of the refrigerant 7 continues until the liquid level in the branch pipe 6f and the liquid level of the refrigerant container 8 become approximately the same.
  • the valve 61 is retightened when the discharge pressure of the refrigerant 7 decreases and the refrigerant 7 is filled with the liquefied refrigerant 7.
  • valve 62 may be open or closed. While the gaseous refrigerant 7 is discharged through the valve 61, it is possible to collect a part of the refrigerant 7 released into the atmosphere and return it to the refrigerant container 8 by maintaining the open state. on the other hand. If the valve 62 is closed, the gaseous refrigerant 7 does not flow into the refrigerant container 8. As a result, since the output of the refrigerator 12 over the period during which the circulation is maintained is not required, the superconducting magnet device 1 can be stably moved even with a small refrigerator.
  • the superconducting magnet device 1 With the superconducting magnet device 1 according to the second embodiment described above, not only can the same effect as in the first embodiment be obtained, but the time required to stop the circulation of the refrigerant 7 can be reduced by the heating of the refrigerant 7. Since this phase change time is not required, the time is further shortened compared with the first embodiment. Further, since it is not necessary to use heat in order to stop the circulation of the refrigerant 7, the refrigerant circulation part 6c and the refrigerant storage part 15 are all constituted by members having low thermal conductivity, and the amount of heat input from the outside of the vacuum vessel 2 It is possible to design with a focus only on reducing the size, and to ease the design constraints.
  • FIG. 5 shows a cross-sectional view of the superconducting magnet device 1 according to the third embodiment.
  • the third embodiment has a structure in which the refrigerant circulation portion 6d that is in thermal contact with the permanent current switch 9 is extended from 6e that is in thermal contact with the superconducting coil 4. Is different.
  • this embodiment has a structure having the heater 51 as in the first embodiment, it may have a system in which the gaseous refrigerant 7 is introduced as in the second embodiment.
  • the permanent current switch 9 is arranged in the vicinity of the superconducting coil 4, and the vacuum vessel 2 and the like The entire containment vessel can be made compact.
  • FIG. 6 is a cross-sectional view of the superconducting magnet device 1 according to the fourth embodiment, and particularly relates to the superconducting coil 4 and the coil bobbin 5.
  • FIG. 7 is a cross-sectional view of the superconducting magnet device 1 shown in FIG.
  • FIG. 8 is a BB cross-sectional view of the superconducting magnet device 1 shown in FIG.
  • FIG. 9 is a bird's eye view in which only the refrigerant circulation flow path 6, the refrigerant container 8, and the permanent current switch 9 of the superconducting magnet apparatus 1 shown in FIG. 6 are taken out.
  • the fourth embodiment is different from the first embodiment in that the central axis 21 of the superconducting coil 4 is oriented in the horizontal direction and the refrigerant circulation part 6e that is in thermal contact with the superconducting coil 4 is a superconducting coil. 4 and the central axis 21 are different from each other in that they are configured as a plurality of arcuate members. 7 and 8, the superconducting magnet device 1 according to the present embodiment has a circular or elliptical cross section on the inner peripheral surface when a cross section perpendicular to the central axis 21 is obtained.
  • the vacuum container 2 is configured, and an open space can be formed along the direction of the central axis 21.
  • the superconducting magnet device 1 includes a plurality of superconducting coils 4 in the direction of the central axis 21.
  • the diameter of each superconducting coil 4 may be different.
  • the shape of the refrigerant circulation portion 6e is different from those of the first to third embodiments. 8 and 9 show the refrigerant circulation section 6e in the present embodiment.
  • the refrigerant circulation section 6 e is mainly composed of an arc-shaped pipe formed along the outer peripheral curved surface of the superconducting coil 4 and a horizontal pipe for circulating the refrigerant 7 in the direction of the central axis 21.
  • positioning of arc-shaped piping is not restricted to the aspect in alignment with the outer periphery of a superconducting coil. If it is structurally acceptable, it may be configured along the inner peripheral surface.
  • the superconducting coil 4 is cooled by providing a heat conduction path 11 penetrating the coil bobbin 5.
  • Arc-shaped pipes may be provided at different positions in the direction of the superconducting coil 4 and the central axis 21.
  • an arcuate pipe or a straight pipe may be arranged at the position AA in FIG.
  • the superconducting coil 4 is cooled by providing the heat conduction path 11 so as to penetrate the coil bobbin 5.
  • the piping structure that does not follow the outer peripheral curved surface is useful for suppressing the internal structure of the vacuum vessel 2 from expanding in the radial direction with respect to the central shaft 21 and miniaturizing the superconducting magnet device 1. is there.
  • FIG. 11A is a schematic diagram of a horizontal MRI apparatus 100.
  • the MRI apparatus requires a static and strong magnetic field (static magnetic field) for imaging, and a superconducting magnet apparatus is used as a component for generating the static magnetic field.
  • the superconducting magnet device 1 of the present embodiment can be used as a device (static magnetic field generator) that generates this static magnetic field. Since the static magnetic field generator in the conventional MRI apparatus employs an immersion cooling method using liquid helium, the consumption of helium accompanying energization and demagnetization of the superconducting magnet is enormous.
  • the amount of the refrigerant 7 used is significantly smaller than that of the immersion cooling, and the consumption amount is in principle the volume of the refrigerant reservoir 15. It can also be suppressed.
  • FIG. 10 is a cross-sectional view of the superconducting magnet device 1 according to the fifth embodiment.
  • the fifth embodiment is provided with a plurality of refrigerant circulation portions 6 e that are in thermal contact with the superconducting coil 4, and is opened by the vacuum vessel 2 and the radiation shield 3 perpendicular to the central axis 21. The difference is that 22 is formed.
  • FIG. 11B is a schematic diagram of the vertical MRI apparatus 100.
  • the MRI apparatus 100 to which the superconducting magnet apparatus 1 of the present embodiment is applied requires a remarkably small amount of the refrigerant 7 to be used as compared with the immersion cooling, and the consumption amount is in principle the volume of the refrigerant reservoir 15. It can also be suppressed.
  • liquid helium is used as the refrigerant 7.
  • the superconducting coil 4 is composed of a high-temperature superconducting wire, liquid nitrogen or the like may be used.
  • a refrigerant circulation type cooling method and a conduction cooling method may be combined.
  • the cooling system of the superconducting magnet apparatus 1 of the present embodiment includes, for example, a superconducting magnet for an accelerator, a superconducting rotating gantry for a particle beam therapy apparatus, a superconducting flyhole, a superconducting bulk body, etc. It can be applied to all devices and members that are required to maintain the superconducting state.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Containers, Films, And Cooling For Superconductive Devices (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

L'invention concerne un dispositif magnétique supraconducteur (1) comprenant au moins une bobine supraconductrice (4), un commutateur de courant permanent (9) qui est relié à la bobine supraconductrice, et des moyens de refroidissement à circulation de réfrigérant qui refroidissent la bobine supraconductrice et le commutateur de courant permanent et qui comprennent un canal à travers lequel circule un réfrigérant. Le dispositif est caractérisé en ce que les moyens de refroidissement comprennent au moins : un récipient à réfrigérant (8) qui retient le réfrigérant liquéfié, un canal de circulation de réfrigérant (6) qui permet au réfrigérant de circuler et un élément de transfert de chaleur (11) qui amène le canal de circulation de réfrigérant en contact thermique avec la bobine supraconductrice et le commutateur de courant permanent; et un moyen d'arrêt qui arrête la circulation du réfrigérant qui s'écoule à travers le canal de circulation de réfrigérant dans le segment entre le récipient à réfrigérant et l'emplacement de l'élément de transfert de chaleur qui est en contact avec le commutateur de courant permanent.
PCT/JP2017/020897 2016-06-30 2017-06-06 Dispositif magnétique supraconducteur et dispositif d'imagerie tomographique par résonance magnétique WO2018003420A1 (fr)

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Cited By (3)

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Publication number Priority date Publication date Assignee Title
WO2019239650A1 (fr) * 2018-06-15 2019-12-19 株式会社日立製作所 Dispositif à électro-aimant supraconducteur
US11651919B2 (en) 2019-03-22 2023-05-16 Koninklijke Philips N.V. System for controlling temperature of persistent current switch
CN116564643A (zh) * 2023-07-10 2023-08-08 苏州八匹马超导科技有限公司 超导磁体装置、超低温系统及超导磁体装置的降温方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019198266A1 (fr) * 2018-04-09 2019-10-17 三菱電機株式会社 Dispositif à aimant supraconducteur
JP6556414B1 (ja) * 2018-04-09 2019-08-07 三菱電機株式会社 超電導磁石装置
JP7280571B2 (ja) * 2019-09-20 2023-05-24 住友電気工業株式会社 永久電流スイッチ及び超電導装置
CN115762953B (zh) * 2023-01-10 2023-06-02 苏州八匹马超导科技有限公司 超导磁体冷却装置及超导磁体设备

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JPS61214588A (ja) * 1985-03-20 1986-09-24 Hitachi Ltd 超電導装置
JPS63283437A (ja) * 1987-05-11 1988-11-21 Hitachi Ltd 超電導蓄電池
JP2009246231A (ja) * 2008-03-31 2009-10-22 Toshiba Corp 極低温冷却制御装置およびその制御方法

Patent Citations (3)

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JPS61214588A (ja) * 1985-03-20 1986-09-24 Hitachi Ltd 超電導装置
JPS63283437A (ja) * 1987-05-11 1988-11-21 Hitachi Ltd 超電導蓄電池
JP2009246231A (ja) * 2008-03-31 2009-10-22 Toshiba Corp 極低温冷却制御装置およびその制御方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019239650A1 (fr) * 2018-06-15 2019-12-19 株式会社日立製作所 Dispositif à électro-aimant supraconducteur
US11651919B2 (en) 2019-03-22 2023-05-16 Koninklijke Philips N.V. System for controlling temperature of persistent current switch
CN116564643A (zh) * 2023-07-10 2023-08-08 苏州八匹马超导科技有限公司 超导磁体装置、超低温系统及超导磁体装置的降温方法
CN116564643B (zh) * 2023-07-10 2023-09-26 苏州八匹马超导科技有限公司 超导磁体装置的降温方法

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