Superconducting electromagnet device

Abstract

The bobbin (4) extends in an axial direction intersecting the vertical direction and has a cylindrical outer shape. On the outer peripheral surface, a plurality of annular groove portions (4a) extending in the circumferential direction are formed at intervals in the axial direction. Inside each of the plurality of annular groove portions (4a), a superconducting coil (1) is wound and accommodated. The cover portion (7) is attached to the bobbin (4) so as to cover each of the plurality of annular groove portions (4a), and together with the plurality of annular groove portions (4a), a plurality of annular flow paths (8) for a refrigerant (3) that cools the superconducting coil (1) are formed. The communication path (17) extends parallel to the axial direction and communicates adjacent annular flow paths (8) among the plurality of annular flow paths (8) with each other.

Description

Technical Field

[0001] The present disclosure relates to a superconducting electromagnet device. Background Art

[0002] As a prior art document disclosing the structure of a superconducting electromagnet device, there is Japanese Patent Application Laid-Open No. 2013-118228 (Patent Document 1). The superconducting electromagnet device described in Patent Document 1 includes a refrigerant circulation flow path, a refrigerator, a superconducting coil, and a protection resistor.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-118228 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the superconducting electromagnet device described in Patent Document 1, in order to suppress the occurrence of quenching caused by the temperature rise of the superconducting coil during excitation and demagnetization of the superconducting coil, a large amount of refrigerant is required.

[0008] The present disclosure has been completed to solve the above problems, and an object thereof is to provide a superconducting electromagnet device capable of reducing the amount of refrigerant used while suppressing the occurrence of quenching of the superconducting coil during excitation and demagnetization of the superconducting coil.

[0009] Means for Solving the Problems

[0010] The superconducting electromagnet device according to the present disclosure includes a superconducting coil, a bobbin, a lid portion, a refrigerant circulation flow path, a refrigerator, and a communication path. The bobbin extends in an axial direction intersecting the vertical direction and has a cylindrical outer shape. A plurality of annular groove portions extending in the circumferential direction are formed on the outer peripheral surface of the bobbin at intervals in the axial direction. The superconducting coil is wound and housed inside each of the plurality of annular groove portions. The lid portion is attached to the bobbin so as to cover each of the plurality of annular groove portions. The lid portion and the plurality of annular groove portions together form a plurality of annular flow paths for the refrigerant that cools the superconducting coil. The refrigerant circulation flow path is provided to circulate the refrigerant. The refrigerant circulation flow path is connected to the plurality of annular flow paths. The refrigerator cools the refrigerant in the refrigerant circulation flow path. The communication path extends parallel to the axial direction and communicates adjacent annular flow paths among the plurality of annular flow paths with each other.

[0011] Effects of the Invention

[0012] According to the present disclosure, a plurality of annular grooves formed in a bobbin and a lid portion mounted on the bobbin constitute a plurality of annular flow paths for a refrigerant that cools a superconducting coil. Adjacent annular flow paths communicate with each other through communication paths, so that while reducing the amount of refrigerant used, the occurrence of quenching of the superconducting coil during excitation and demagnetization of the superconducting coil can be suppressed. Description of the Drawings

[0013] Figure 1 is a front view showing the structure of the superconducting electromagnet device of Embodiment 1.

[0014] Figure 2 is viewed from the direction of the arrow of line II-II Figure 1 partial cross-sectional view of the superconducting electromagnet device.

[0015] Figure 3 is viewed from the direction of the arrow of line III-III Figure 2 cross-sectional view of the superconducting electromagnet device.

[0016] Figure 4 is a cross-sectional view showing the arrangement of the communication paths in the superconducting electromagnet device of the first modification of Embodiment 1.

[0017] Figure 5 is a cross-sectional view showing the arrangement of the communication paths in the superconducting electromagnet device of the second modification of Embodiment 1.

[0018] Figure 6 is a cross-sectional view showing the superconducting electromagnet device of Embodiment 2. Detailed Embodiments

[0019] Hereinafter, the superconducting electromagnet device of each embodiment will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

[0020] Embodiment 1

[0021] Figure 1 is a front view showing the structure of the superconducting electromagnet device of Embodiment 1. Figure 2 is viewed from the direction of the arrow of line II-II Figure 1 of the superconducting electromagnet device. In Figure 1 the heat shield 5 and the vacuum vessel 6 described later are not shown.

[0022] As Figure 1 and Figure 2 shown, the superconducting electromagnet device 100 includes a superconducting coil 1, a bobbin 4, a lid portion 7, a refrigerant circulation flow path 11, a refrigerator 16, and a communication path 17.

[0023] The superconducting coil 1 is insulated by covering its surface with an insulating member 2. The superconducting coil 1 is cooled below the critical temperature by contacting a refrigerant 3 via the insulating member 2. In the present embodiment, the refrigerant 3 is helium.

[0024] The bobbin 4 extends in an axial direction intersecting the vertical direction and has a cylindrical outer shape, and has flanges at both ends in the above-mentioned axial direction. In the bobbin 4, on the outer peripheral surface between the flanges, a plurality of annular groove portions 4a extending in the circumferential direction are formed at intervals in the above-mentioned axial direction. The superconducting coil 1 covered with the insulating member 2 is wound and accommodated inside each of the plurality of annular groove portions 4a.

[0025] As Figure 2 shown, the superconducting electromagnet device 100 of the present embodiment further includes a thermal shield 5 and a vacuum vessel 6. The thermal shield 5 covers the outside of the bobbin 4 with a gap therebetween. The vacuum vessel 6 is provided outside the thermal shield 5. The inside of the vacuum vessel 6 is maintained in a vacuum state. The superconducting electromagnet device 100 has a vacuum heat insulation structure inside the vacuum vessel 6.

[0026] The cover portion 7 is attached to the bobbin 4 so as to cover each of the plurality of annular groove portions 4a. The cover portion 7 is attached to the bobbin 4 by welding, for example. The cover portion 7 also covers the region between the annular groove portions 4a adjacent to each other in the above-mentioned axial direction on the outer peripheral surface of the bobbin 4. The cover portion 7 is formed of a substantially cylindrical plate material that covers the entire plurality of annular groove portions 4a from the outside.

[0027] The cover portion 7 and the plurality of annular groove portions 4a together constitute a plurality of annular flow paths 8 for the refrigerant 3 that cools the superconducting coil 1. The liquid-phase refrigerant 3 flows inside each of the plurality of annular flow paths 8. That is, the internal space sandwiched between the plurality of annular flow paths 8 and the cover portion 7 becomes the plurality of annular flow paths 8 through which the refrigerant 3 circulates in the circumferential direction of the bobbin 4.

[0028] The cross-sectional area of each of the plurality of annular flow paths 8 observed from the circumferential direction of the bobbin 4 is set to be able to circulate an amount of the refrigerant 3 that satisfies the cooling performance during operation and the initial cooling performance at the start of operation. In addition, in order to reduce the amount of the refrigerant 3, as Figure 2 shown, the distance between the cover portion 7 and the superconducting coil 1 provided in the annular groove portion 4a can be smaller than the depth of the annular groove portion 4a.

[0029] As Figure 1 shown, the refrigerant circulation flow path 11 includes a refrigerant pipe 12, an upper tank 13, an upper header 14, and a lower header 15. As Figure 1As shown, the refrigerant pipe 12 extends along the outer peripheral surface of the coil frame 4 at a distance from the outer peripheral surface of the coil frame 4. The interior of the refrigerant pipe 12 is filled with the liquid refrigerant 3. The upper end of the refrigerant pipe 12 is connected to the upper tank 13. The lower end of the refrigerant pipe 12 is connected to the lower header 15.

[0030] The upper header 14 is connected to the upper tank 13 and branches to be connected to the upper part of each of the plurality of annular flow paths 8. The lower header 15 is connected to the refrigerant pipe 12 and branches to be connected to the lower part of each of the plurality of annular flow paths 8. In this way, in the refrigerant circulation flow path 11, the refrigerant 3 is formed to circulate through the upper tank 13, the refrigerant pipe 12, the lower header 15, the plurality of annular flow paths 8, and the upper header 14.

[0031] The refrigerator 16 cools the refrigerant 3 in the refrigerant circulation flow path 11. Specifically, a refrigeration stage at the front end of the refrigerator 16 is connected to the upper part of the upper tank 13.

[0032] like Figure 2 As shown, the communication passage 17 extends in parallel with the axial direction of the coil bobbin 4 , and allows mutually adjacent annular flow passages 8 among the plurality of annular flow passages 8 to communicate with each other.

[0033] Figure 3 Observe from the direction of the arrow on line III-III Figure 2 A cross-sectional view of a superconducting electromagnet device. Figure 2 and Figure 3 As shown, in this embodiment, the communication path 17 is formed by the gap between the coil frame 4 and the cover 7. Specifically, a part of the inner surface of the cover 7 that faces the outer peripheral surface of the coil frame 4 located between the annular flow paths 8 is separated from the outer peripheral surface of the coil frame 4, and a gap is formed between the outer peripheral surface of the coil frame 4 located between the annular flow paths 8 and the inner surface of the cover 7. This gap becomes the communication path 17.

[0034] In addition, the communication path 17 is not limited to the case where it is formed by the gap between the coil frame 4 and the cover 7, and can also be formed by a through hole formed in the coil frame 4, and can also be formed by a gap between the annular cover and the outer peripheral surface of the coil frame 4, which is ensured by a resin or metal spacer arranged on the outer peripheral surface of the coil frame 4 at intervals from each other in the circumferential direction of the coil frame 4. In addition, a groove extending in the axial direction can be provided on the outer peripheral surface of the coil frame 4 instead of the through hole extending in the axial direction as the communication path 17.

[0035] In this embodiment, if Figure 3As shown, there is one communication path 17 at the lower side position of the bobbin 4, and one each at the left side position and the right side position of the bobbin 4. The cross-sectional area of the communication path 17 as observed from the axial direction of the bobbin 4 is as described later. As long as the liquid-phase refrigerant 3 can be replenished through the communication path 17, it can be smaller than the cross-sectional area of each of the plurality of annular flow paths 8. For example, the cross-sectional area of the communication path 17 is one-twentieth or more and one-tenth or less of the cross-sectional area of each of the plurality of annular flow paths 8 as observed from the circumferential direction of the bobbin 4. By providing the communication path 17 with such a small cross-sectional area, not only can the liquid-phase refrigerant 3 be replenished to each annular flow path 8, but also the amount of the refrigerant 3 can be reduced.

[0036] The superconducting electromagnet device 100 of the present embodiment further includes Figure 1 the protection resistor 10 and the current lead 9 as shown. The protection resistor 10 is disposed inside the refrigerant pipe 12. The protection resistor 10 has the function of preventing the performance degradation or burnout of the superconducting coil 1 when a quench occurs. The protection resistor 10 is electrically connected in parallel with the superconducting coil 1. When the superconducting coil 1 is excited and demagnetized, the protection resistor 10 is energized and transiently heated. The cross-sectional shape of the protection resistor 10 in the present embodiment is rectangular, but the cross-sectional shape of the protection resistor 10 is not limited to rectangular, and may also be annular or circular.

[0037] The current lead 9 is connected to the superconducting coil 1 through the upper tank 13 and the refrigerant pipe 12. In the superconducting coil 1, the portion located inside one annular flow path 8 and the portion located inside another annular flow path 8 adjacent to the one annular flow path 8 are connected to each other inside the upper tank 13 or inside the annular flow path 8.

[0038] Here, the flow of the refrigerant 3 in the superconducting electromagnet device 100 during normal operation will be described. The liquid level of the refrigerant 3 is located inside the upper tank 13. That is, the lower part inside the upper tank 13 is filled with the refrigerant 3. The main heat generation cause of the superconducting coil 1 in the superconducting electromagnet device 100 during normal operation is the heat input from the outside through the vacuum vessel 6 and the thermal shield 5.

[0039] The refrigerant 3 located inside each of the plurality of annular flow paths 8 has a decreased density due to the heat input from the outside. Therefore, inside each of the plurality of annular flow paths 8, an upward flow of the refrigerant 3 is generated. As Figure 1 indicated by the arrows in, the refrigerant 3 flows separately in opposite directions in the circumferential direction of the bobbin 4 in each of the plurality of annular flow paths 8.

[0040] The refrigerant 3 that flows in such a way as to rise inside each of the plurality of annular flow paths 8 merges through the upper header 14 and flows into the upper tank 13. The refrigerant in the upper tank 13 is cooled by the refrigerator 16 and its density becomes higher. As a result, the refrigerant 3 flows from the upper tank 13 into the lower header 15. The refrigerant 3 after branching in the lower header 15 flows into each of the plurality of annular flow paths 8. Thus, due to the density difference of the refrigerant 3, the refrigerant 3 circulates in the refrigerant circulation flow path 11.

[0041] Next, the transient heat generation phenomenon of the superconducting coil 1 in the superconducting electromagnet device 100 during excitation and demagnetization of the superconducting coil 1 will be described. In the superconducting electromagnet device 100 during excitation and demagnetization of the superconducting coil 1, the protective resistor 10 is energized and transiently generates heat, and due to the influence of this heat factor and strain, etc., a part of the superconducting coil 1 sometimes generates heat. In this case, the refrigerant 3 inside the annular flow path 8 that houses the heat generating part of the superconducting coil 1 vaporizes, so that the liquid-phase refrigerant 3 decreases. The liquid-phase refrigerant 3 corresponding to the reduced amount is replenished through the lower header 15, but when the time required to replenish the liquid-phase refrigerant 3 is long, the temperature of the heat generating part of the superconducting coil 1 further rises and a quench may occur.

[0042] Therefore, in the superconducting electromagnet device 100 of the present embodiment, the adjacent annular flow paths 8 are connected to each other through the communication path 17, so that the liquid-phase refrigerant 3 can be replenished through the lower header 15 to the annular flow path 8 that houses the heat generating part of the superconducting coil 1, and the liquid-phase refrigerant 3 can be replenished from the annular flow path 8 adjacent to the annular flow path 8 that houses the heat generating part of the superconducting coil 1 to the annular flow path 8 that houses the heat generating part of the superconducting coil 1 through the communication path 17. Therefore, compared with the case where only the liquid-phase refrigerant 3 is replenished through the lower header 15, the time required for replenishment can be shortened. Furthermore, the heat generating part of the superconducting coil 1 can be cooled earlier and the occurrence of a quench in the superconducting coil 1 can be suppressed.

[0043] In addition, the arrangement of the communication path 17 is not limited to Figure 3 the position shown. Here, the arrangement of the communication path 17 in the superconducting electromagnet device of the modification example of the present embodiment will be described.

[0044] Figure 4 is a cross-sectional view showing the arrangement of the communication path in the superconducting electromagnet device of the first modification example of Embodiment 1. In Figure 4 it, it is shown by a cross-section taken from the same direction as Figure 3 . As Figure 4 shown, in the superconducting electromagnet device of the first modification example, the communication paths 17 are provided at equal intervals in the circumferential direction of the bobbin 4. In the first modification example, there are 4 communication paths 17 arranged at equal intervals, but the installation positions of the communication paths 17 are not limited to 4, as long as there are a plurality of them.

[0045] Figure 5 It is a cross-sectional view showing the configuration of the communication paths in the superconducting electromagnet device according to the second modified example of Embodiment 1. In Figure 5 it, a cross-section is shown when viewed from the same direction as Figure 3 . As shown in Figure 5 , in the superconducting electromagnet device according to the second modified example, more communication paths 17 are arranged in the lower half of the bobbin than in the upper half. In the second modified example, six communication paths 17 are arranged, but the arrangement positions of the communication paths 17 are not limited to six, and may be one or more.

[0046] In the superconducting electromagnet device 100 of Embodiment 1, a plurality of annular flow paths 8 for the refrigerant 3 for cooling the superconducting coil 1 are formed by a plurality of annular groove portions 4a formed in the bobbin 4 and a lid portion 7 attached to the bobbin 4. Adjacent annular flow paths 8 communicate with each other through the communication paths 17, so that the heat generating portion of the superconducting coil 1 can be cooled as early as possible by the refrigerant 3 inside the plurality of annular flow paths 8. Therefore, it is possible to reduce the amount of refrigerant 3 used while suppressing the occurrence of quenching of the superconducting coil 1 during excitation and demagnetization of the superconducting coil 1. In addition, inside the annular flow path 8, the superconducting coil 1 is in contact with the refrigerant 3 via the insulating member 2, so that the thermal resistance between the superconducting coil 1 and the refrigerant 3 can be reduced and the superconducting coil 1 can be effectively cooled.

[0047] In the superconducting electromagnet device 100 of Embodiment 1, the communication path 17 is formed by the gap between the bobbin 4 and the lid portion 7, so that the size of the gap can be adjusted by the shape of the lid portion 7. Therefore, the amount of refrigerant flowing through the communication path 17 can be arbitrarily set without changing the shape of the bobbin 4.

[0048] In the superconducting electromagnet device according to the first modified example of Embodiment 1, by arranging the communication paths 17 at equal intervals in the circumferential direction of the bobbin 4, the liquid-phase refrigerant 3 can be supplied to the annular flow path 8 accommodating the heat generating portion of the superconducting coil 1 through the communication paths 17 located near the heat generating portion of the superconducting coil 1. As a result, the heat generating portion of the superconducting coil 1 can be cooled as early as possible and the occurrence of quenching of the superconducting coil 1 can be suppressed.

[0049] In the superconducting electromagnet device according to the second modified example of Embodiment 1, by arranging more communication paths 17 in the lower half of the bobbin 4 than in the upper half, the liquid-phase refrigerant 3 can be supplied to the annular flow path 8 accommodating the heat generating portion of the superconducting coil 1 through the communication paths 17 in the lower half of the bobbin 4 where the hydraulic pressure of the refrigerant 3 is relatively high. As a result, the heat generating portion of the superconducting coil 1 can be cooled as early as possible and the occurrence of quenching of the superconducting coil 1 can be suppressed.

[0050] Embodiment 2

[0051] Hereinafter, the superconducting electromagnet device of Embodiment 2 will be described. The superconducting electromagnet device of Embodiment 2 differs from that of Embodiment 1 only in the structure of the communication path. Therefore, other structures will not be described repeatedly.

[0052] Figure 6 is a cross-sectional view showing the superconducting electromagnet device of Embodiment 2. As Figure 6 shown, the cover portion 7 is mounted on the bobbin 4 in such a manner as to contact the outer peripheral surface of the bobbin 4 between the annular groove portions 4a and cover each of the plurality of annular groove portions 4a.

[0053] The bobbin 4 is formed with a through-hole between the annular groove portions 4a. The through-hole is located on the outer peripheral side of the superconducting coil 1 and the insulating member 2 and penetrates parallel to the axial direction of the bobbin 4. That is, the outer diameter of the bobbin 4 is larger than the outer diameters of the superconducting coil 1 and the insulating member 2. In the present embodiment, the communication path 17a is constituted by the through-hole formed in the bobbin 4. The through-hole is provided before the cover portion 7 is mounted on the bobbin 4.

[0054] In the superconducting electromagnet device of Embodiment 2, a plurality of annular flow paths 8 for the refrigerant 3 for cooling the superconducting coil 1 are constituted by the plurality of annular groove portions 4a formed in the bobbin 4 and the cover portion 7 mounted on the bobbin 4. And adjacent annular flow paths 8 communicate with each other through the communication path 17a formed in the bobbin 4, so that the amount of refrigerant 3 used can be reduced while suppressing the generation of quench of the superconducting coil 1 during excitation and demagnetization of the superconducting coil 1.

[0055] In the superconducting electromagnet device of Embodiment 2, by forming the communication path 17a with the through-hole formed in the bobbin 4, the shape of the cover portion 7 can be made simple.

[0056] In addition, the above-described embodiments disclosed this time are illustrative in all aspects and do not serve as a basis for restrictive interpretation. Therefore, the technical scope of the present disclosure is not limited to the above-described embodiments. In addition, all modifications including those having the same meaning and scope as the claims are included. In the description of the above embodiments, structures that can be combined may also be combined with each other.

[0057] Description of Reference Numerals

[0058] 1 Superconducting coil, 2 Insulating member, 3 Refrigerant, 4 Bobbin, 4a Annular groove portion, 5 Thermal shield, 6 Container, 7 Cover portion, 8 Annular flow path, 9 Current lead, 10 Protection resistor, 11 Refrigerant circulation flow path, 12 Refrigerant pipe, 13 Upper tank, 14 Upper header, 15 Lower header, 16 Refrigerator, 17, 17a Communication path, 100 Superconducting electromagnet device.

Claims

1. A superconducting electromagnet device, wherein, Comprising: A superconducting coil; An insulating member covering the superconducting coil; A bobbin that extends in an axial direction intersecting the vertical direction and has a cylindrical outer shape. On the outer peripheral surface, a plurality of annular groove portions extending in the circumferential direction are formed at intervals in the axial direction, and the superconducting coil is wound and accommodated inside each of the plurality of annular groove portions; A cover portion that is mounted on the bobbin so as to cover each of the plurality of annular groove portions, and together with the plurality of annular groove portions constitutes a plurality of annular flow paths for a refrigerant that cools the superconducting coil; A refrigerant circulation flow path that is connected to the plurality of annular flow paths and is used to circulate the refrigerant; A refrigerator that cools the refrigerant in the refrigerant circulation flow path; And A communication path that extends parallel to the axial direction and communicates adjacent annular flow paths among the plurality of annular flow paths with each other, The communication path is located on the outer peripheral side of the superconducting coil and the insulating member, The distance between the cover portion and the superconducting coil is smaller than the depth of the plurality of annular groove portions.

2. The superconducting electromagnet device according to claim 1, wherein, The communication path is constituted by a gap between the bobbin and the cover portion.

3. The superconducting electromagnet device according to claim 1, wherein, The communication path is constituted by a through hole formed in the bobbin.

4. The superconducting electromagnet device according to any one of claims 1 to 3, wherein, The communication paths are arranged at equal intervals in the circumferential direction.

5. The superconducting electromagnet device according to any one of claims 1 to 3, wherein, The communication paths are arranged in a greater number in the lower half of the bobbin than in the upper half.

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