JP7477960B2 - Superconducting coil device - Google Patents

Description

The present invention relates to a superconducting coil device.

When in use, superconducting coils are cooled to an extremely low temperature at which they become superconducting, and there are two main cooling methods for this. One is to cool the superconducting coil by immersing it in an extremely low temperature refrigerant such as liquid helium, and is also called immersion cooling. In the other method, no liquid refrigerant is used. The superconducting coil is cooled directly by a cryogenic refrigerator, such as a Gifford-McMahon (GM) refrigerator. This is also called conduction cooling.

JP 2009-243820 A

A superconducting coil is formed by winding superconducting wire. Therefore, in the case of conduction cooling, the radial heat conduction inside the superconducting coil can depend on the contact thermal resistance between the wound superconducting wire. This is particularly noticeable when the superconducting coil is not impregnated with a resin material during its manufacture. However, in terms of manufacturing, it is not easy to control the contact thermal resistance between the superconducting wire so that it is uniform throughout the entire superconducting coil. If there is local non-uniformity in the heat conduction inside the superconducting coil, this can lead to thermal instability of the superconducting coil. Thermal instability is undesirable because it can further lead to thermal runaway that causes the loss of superconductivity.

One exemplary objective of one embodiment of the present invention is to improve the thermal stability of a superconducting coil.

According to one aspect of the present invention, a superconducting coil device includes a superconducting coil and a coil reinforcement case that is arranged to surround the superconducting coil so as to reinforce the superconducting coil and that hermetically contains a cooling gas together with the superconducting coil.

According to one aspect of the present invention, a superconducting coil device includes a superconducting coil, a coil case that hermetically contains a cooling gas together with the superconducting coil, a superconducting current lead connected to the superconducting coil and contained in the coil case, and a metal current lead connected to the superconducting current lead and attached to the coil case so as to seal the cooling gas.

In addition, any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid aspects of the present invention.

The present invention can improve the thermal stability of superconducting coils.

1 is a diagram illustrating a schematic diagram of a superconducting coil device according to an embodiment. FIG. 2 is a schematic diagram showing cryogenic cooling of the superconducting coil arrangement shown in FIG. 1; 2 is a schematic diagram of an exemplary configuration of the superconducting coil shown in FIG. 1; FIG. FIG. 2 is a schematic diagram illustrating an exemplary configuration of the coil reinforcement case shown in FIG. 1 together with a superconducting coil. 13A and 13B are diagrams illustrating schematic diagrams of modified examples of the coil reinforcement case. 2 is a diagram illustrating a current lead portion according to an embodiment of the present invention that can be applied to the superconducting coil device illustrated in FIG. 1. FIG. 7(a) and 7(b) are schematic diagrams illustrating a modification of the embodiment of FIG.

Below, the embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The scale and shape of each part shown in the drawings are set for convenience in order to facilitate explanation, and should not be interpreted as being limiting unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. All features and combinations thereof described in the embodiments are not necessarily essential to the invention.

Figure 1 is a schematic diagram of a superconducting coil device 10 according to an embodiment. The superconducting coil device 10 includes a superconducting coil 12, and is configured to generate a strong magnetic field by passing electricity through the superconducting coil 12 while the superconducting coil 12 is cooled to an extremely low temperature below the superconducting transition temperature. The superconducting coil device 10 is mounted in high magnetic field equipment as a magnetic field source for, for example, an NMR system, an MRI system, an accelerator such as a cyclotron, a high energy physics system such as a nuclear fusion system, or other high magnetic field equipment (not shown), and can generate the high magnetic field required for the equipment.

The superconducting coil 12 is, for example, a high-temperature superconducting coil.

The superconducting coil device 10 includes a coil reinforcing case 14 that is disposed around the superconducting coil 12 to reinforce the superconducting coil 12. The coil reinforcing case 14 hermetically contains the cooling gas 16 together with the superconducting coil 12. During excitation, a strong electromagnetic force acts on the superconducting coil 12, which expands the superconducting coil 12 in the radial direction, due to the interaction between the large current flowing through the superconducting coil 12 and the strong magnetic field generated thereby. The coil reinforcing case 14 provides the mechanical strength required to reinforce the superconducting coil 12 against this electromagnetic force, and is formed of a metal material such as stainless steel or other suitable high-strength material to withstand the pressure of the contained cooling gas 16.

The cooling gas 16 becomes part of the heat transfer path from the coil reinforcement case 14 to the superconducting coil 12. The cooling gas 16 is sealed in the coil reinforcement case 14 at high pressure. The sealing pressure of the cooling gas 16 may be, for example, about 7.5 MPa to about 30 MPa (or, for example, about 10 MPa to about 20 MPa) at room temperature (e.g., 300 K). That is, the sealing pressure of the cooling gas 16 may be, for example, about 0.5 MPa to about 2 MPa (or, for example, about 0.67 MPa to about 1.33 MPa) at an extremely low temperature (e.g., 20 K). The cooling gas 16 is a substance that is in a gaseous state in such a usage environment, such as helium gas.

The coil reinforcement case 14 may be provided with a gas supply port 18 for supplying the cooling gas 16 into the case. However, the gas supply port 18 is opened when the cooling gas 16 is supplied to the coil reinforcement case 14, but is closed when the gas supply is completed, and is sealed so that the cooling gas 16 does not leak out of the case.

The superconducting coil device 10 further includes a current lead section 20 for connecting a power source (not shown) to the superconducting coil 12. The current lead section 20 may have a metal current lead formed of a metal material with excellent conductivity, such as pure copper, such as oxygen-free copper, or may have a superconducting current lead formed of a superconducting wire (e.g., a high-temperature superconducting wire). The current lead section 20 is introduced from outside the case into the case through an airtight feedthrough provided in the coil reinforcement case 14, and is connected to the superconducting coil 12.

The superconducting coil device 10 may further include a soft material layer 22 interposed between the superconducting coil 12 and the coil reinforcement case 14. The soft material layer 22 is sandwiched between the superconducting coil 12 and the coil reinforcement case 14 to fill any gap that may exist between them, thereby improving the thermal contact between the superconducting coil 12 and the coil reinforcement case 14. The soft material layer 22 may be formed of, for example, a resin material such as a fluororesin (e.g., PTFE) sheet or other soft material suitable for use at extremely low temperatures. As an example, in FIG. 1, the soft material layer 22 is provided between the lower surface of the superconducting coil 12 and the bottom surface of the coil reinforcement case 14, but it may also be provided on the side and/or upper surface of the superconducting coil 12 in addition to or instead of this.

Figure 2 is a schematic diagram showing cryogenic cooling of the superconducting coil device 10 shown in Figure 1. When in use, the superconducting coil device 10 is placed in a vacuum vessel 30 such as a cryostat. A vacuum is created around the coil reinforcement case 14.

The cryogenic refrigerator 32 is installed in the vacuum vessel 30. The cryogenic refrigerator 32 includes a first-stage cooling stage 32a and a second-stage cooling stage 32b arranged in the vacuum vessel 30. The cryogenic refrigerator 32 includes a compressor (not shown) for a working gas (e.g., helium gas) and an expander also called a cold head. The compressor and the expander form a refrigeration cycle of the cryogenic refrigerator 32, whereby the first-stage cooling stage 32a and the second-stage cooling stage 32b are each cooled to a desired cryogenic temperature. The first-stage cooling stage 32a is cooled to, for example, 50K to 80K, and the second-stage cooling stage 32b is cooled to, for example, 10K to 20K. The first-stage cooling stage 32a and the second-stage cooling stage 32b are formed of, for example, a metal material such as copper or other material with high thermal conductivity.

Cryogenic refrigerator 32 is, by way of example, a two-stage Gifford-McMahon (GM) refrigerator, but may also be a pulse tube refrigerator, a Stirling refrigerator, or other type of cryogenic refrigerator. Cryogenic refrigerator 32 may also be a single-stage GM refrigerator or other type of cryogenic refrigerator.

The vacuum vessel 30 may also be provided with a heat shield 34 that is thermally coupled to the first cooling stage 32a and cooled to the cooling temperature of the first cooling stage 32a. The heat shield 34 is arranged to surround the superconducting coil device 10, the second cooling stage 32b of the cryogenic refrigerator 32, or other low-temperature parts that are cooled to a lower temperature, and can thermally protect these low-temperature parts from external radiant heat. The heat shield 34 is formed of a metal material such as copper or other material with high thermal conductivity.

The heat shield 34 may be thermally coupled to the first-stage cooling stage 32a via the first-stage heat transfer member 36a. The first-stage heat transfer member 36a may be formed, for example, as a bundle of thin wires or a laminate of foils so as to be flexible, and may be formed of a highly thermally conductive material similar to the heat shield 34. Alternatively, the heat shield 34 may be attached directly to the first-stage cooling stage 32a or attached via a rigid heat transfer member.

The coil reinforcement case 14 is thermally coupled to a cryogenic refrigerator 32 outside the coil reinforcement case 14, and the superconducting coil 12 is cooled by the cryogenic refrigerator 32 via the coil reinforcement case 14 and the cooling gas 16. The superconducting coil device 10 is configured as a conduction cooling type.

The coil reinforcement case 14 is thermally coupled to the second-stage cooling stage 32b and cooled to the cooling temperature of the second-stage cooling stage 32b. The coil reinforcement case 14 may be thermally coupled to the second-stage cooling stage 32b via a second-stage heat transfer member 36b. The second-stage heat transfer member 36b may be formed, for example, as a bundle of fine wires or a laminate of foils to be flexible, similar to the first-stage heat transfer member 36a, and may be formed of a highly thermally conductive material such as copper. Alternatively, the coil reinforcement case 14 may be attached directly to the second-stage cooling stage 32b or attached via a rigid heat transfer member.

A heat transfer plate 38 may be attached to the outer surface of the coil reinforcement case 14. One end of the two-stage heat transfer member 36b is attached to the two-stage cooling stage 32b, and the other end of the two-stage heat transfer member 36b is attached to the heat transfer plate 38, so that the coil reinforcement case 14 may be thermally coupled to the two-stage cooling stage 32b via the two-stage heat transfer member 36b and the heat transfer plate 38. Since the heat transfer plate 38 is in surface contact with the coil reinforcement case 14, the heat transfer between the two-stage cooling stage 32b and the coil reinforcement case 14 can be improved compared to when the two-stage heat transfer member 36b is connected at one point on the coil reinforcement case 14. The heat transfer plate 38 is formed of a metal material such as copper or other highly heat conductive material.

As an example, the heat transfer plate 38 is provided on the upper outer surface of the coil reinforcement case 14, but may also be provided on the side and/or underside of the coil reinforcement case 14, or alternatively.

The current lead portion 20 is taken out from inside the vacuum vessel 30 through a vacuum feedthrough provided in the vacuum vessel 30, and connects the superconducting coil 12 to a power source (not shown) outside the vacuum vessel 30.

In this way, the superconducting coil 12 is cooled to the cooling temperature of the two-stage cooling stage 32b by the two-stage cooling stage 32b of the cryogenic refrigerator 32 via the two-stage heat transfer member 36b, the heat transfer plate 38, the coil reinforcement case 14, and the cooling gas 16. By passing electricity through the superconducting coil 12 via the current lead portion 20, the superconducting coil device 10 can generate a strong magnetic field.

Figure 3 is a schematic diagram showing an exemplary configuration of the superconducting coil 12 shown in Figure 1. The superconducting coil 12 is a single pancake coil formed by winding tape-shaped high-temperature superconducting wire 40, also known as REBCO wire, in a layered manner in the coil radial direction 42.

The high-temperature superconducting wire 40 is constructed by forming a superconducting layer 40c on a substrate 40a via an intermediate layer 40b, forming a first stabilization layer 40d on the superconducting layer 40c, and coating the outer periphery of these with a second stabilization layer 40e.

The substrate 40a is made of a metal such as nickel alloy (Hastelloy), silver, or a silver alloy, and has a thickness of, for example, 100 μm and a width of 10 mm. Hastelloy is an alloy whose main component is nickel and which also contains chromium and molybdenum, and has good heat resistance and mechanical strength. The intermediate layer 40b is made of a compound such as gadolinium zirconium oxide (Gd.Zr oxide), magnesium oxide (MgO), yttrium stabilized zirconium (YSZ), barium zirconium oxide (Ba.Zr oxide), or cerium oxide (CeO2), and has a thickness of, for example, 500 nm and a width of 10 mm.

The superconducting layer 40c is formed, for example, to a thickness of about 1 μm and a width of 10 mm by CVD (chemical vapor deposition) of a rare earth oxide superconductor. Examples of rare earth elements include lanthanum (La), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), dysprosium (Dy), holmium (Ho), erbium (Er), yttrium (Y), and ytterbium (Yb). Examples of rare earth oxides include RE Ba Cu O, where RE represents a rare earth element. Specific examples of the superconducting layer 40c include yttrium barium copper oxide (Y Ba Cu oxide), lanthanum barium copper oxide (La Ba Cu oxide), and the like.

The first stabilization layer 40d is formed by sputtering a metal such as silver, for example, to a thickness of about 15 μm and a width of 10 mm. The second stabilization layer 40e is formed by plating a metal such as copper, for example, to a thickness of about 50 μm.

Conventionally, in low-temperature superconducting coils made of low-temperature superconducting wire such as NbTi, impregnation with a resin material such as epoxy resin is often used when manufacturing the coil. The resin material impregnated between the wire wound in a coil shape hardens and strongly fixes the wire together, increasing the mechanical strength of the coil. The impregnating resin helps to suppress deformation of the coil that can occur due to the strong electromagnetic force generated inside the coil during coil excitation. The impregnating resin also helps to uniformly form a heat transfer path inside the coil that thermally bonds the wire together, improving the thermal stability of the coil.

However, such impregnation treatment is not suitable for the superconducting coil 12 formed from the high-temperature superconducting wire 40. The resin material tends to bond the wires together too strongly compared to the peel strength between the layers of the high-temperature superconducting wire 40. This is because internal stress that may occur during use of the superconducting coil 12 is concentrated inside the low-strength high-temperature superconducting wire 40, which may cause peeling between the layers of the high-temperature superconducting wire 40, which is weaker than the impregnated resin portion, and may destroy the high-temperature superconducting wire 40.

Therefore, the superconducting coil 12 is not impregnated during the manufacturing process. Therefore, the superconducting coil 12 does not have an impregnating material between the stacked high-temperature superconducting wires 40. A superconducting coil formed from superconducting wires that have not been insulated, such as the superconducting coil 12, may also be called a no-insulation (NI) superconducting coil. Even if a normal conductive portion occurs locally for some reason during excitation, the current can be diverted to the adjacent wire, which has the advantage of enabling stable excitation. It is also possible to achieve a high current density.

On the other hand, in the superconducting coil 12, which is an uninsulated coil, the thermal conduction in the coil radial direction 42 strongly depends on the contact thermal resistance between the wound high-temperature superconducting wires 40. In terms of manufacturing, it is not necessarily easy to control the contact thermal resistance between the high-temperature superconducting wires 40 so that it is uniform throughout the coil. If there is local non-uniformity in the thermal conduction within the coil, this can lead to thermal instability in the coil, which is undesirable.

In contrast, according to the superconducting coil device 10 of the embodiment, as shown in FIG. 1, the coil reinforcement case 14 is filled with cooling gas 16, and the superconducting coil 12 is housed in the coil reinforcement case 14 together with the cooling gas 16. The cooling gas 16 penetrates the small gaps 44 (see FIG. 3) between the high-temperature superconducting wires 40 that form the superconducting coil 12, filling the gaps 44. In this way, the cooling gas 16 forms a heat transfer path between the high-temperature superconducting wires 40. This promotes heat conduction inside the superconducting coil 12, improving the thermal stability of the superconducting coil 12.

Figure 4 is a diagram showing an example configuration of the coil reinforcing case 14 shown in Figure 1 together with the superconducting coil 12. Figure 4 shows a schematic cross section of the superconducting coil device 10 along a plane including the central axis of the superconducting coil 12. The superconducting coil 12 is formed into a circular ring shape by winding high-temperature superconducting wire 40 as shown in Figure 3.

The coil reinforcement case 14 comprises a case outer frame 14a arranged adjacent to the outer peripheral surface of the superconducting coil 12, a case upper plate 14b arranged adjacent to the upper end surface of the superconducting coil 12, and a case lower plate 14c arranged adjacent to the lower end surface of the superconducting coil 12. The case outer frame 14a supports the outer peripheral surface of the superconducting coil 12, the case upper plate 14b supports the upper end surface of the superconducting coil 12, and the case lower plate 14c supports the lower end surface of the superconducting coil 12.

When the superconducting coil 12 has an annular shape, the coil reinforcing case 14 may be a cylindrical box that fits the superconducting coil 12 exactly. Therefore, the case outer frame 14a may be an annular frame that extends in the circumferential direction of the coil along the outer circumferential surface of the superconducting coil 12. The case upper plate 14b and the case lower plate 14c may be circular disk-shaped plates that extend along the upper and lower end surfaces of the superconducting coil 12, respectively.

The upper case plate 14b is airtightly joined to the outer peripheral frame 14a, and the lower case plate 14c is airtightly joined to the outer peripheral frame 14a. The outer periphery of the upper case plate 14b is joined to the upper end of the outer peripheral frame 14a, and the outer periphery of the lower case plate 14c is joined to the lower end of the outer peripheral frame 14a. There are various joining methods, but for example, they may be joined by welding, or they may be mechanically joined with joining parts such as bolts by sandwiching a metal sealing member such as a metal O-ring between the two members to be joined.

In addition, in Figure 4, thick arrows indicate the electromagnetic force 50 acting radially on the coil during excitation of the superconducting coil 12, and thin arrows indicate the mechanical internal stress 52 acting on the upper case plate 14b and the lower case plate 14c of the coil reinforcement case 14 against this electromagnetic force 50. In this way, the coil reinforcement case 14 reinforces the superconducting coil 12, and the entire structure including the superconducting coil 12 and the coil reinforcement case 14 can provide mechanical support against the strong electromagnetic force 50.

The coil reinforcement case 14 must be designed to withstand not only the electromagnetic force 50 but also the pressure of the cooling gas 16 sealed inside. Since the superconducting coil 12 is cooled to an extremely low temperature during excitation, the pressure of the cooling gas 16 at this time is relatively low (for example, about 1 MPa) as described above. On the other hand, when performing maintenance on the superconducting coil device 10, the superconducting coil device 10 is heated to room temperature. Since the pressure of the cooling gas 16 also increases in proportion to the temperature, the pressure of the cooling gas 16 in the coil reinforcement case 14 at room temperature is much higher than at extremely low temperatures. For example, if the temperature is raised from 20K to 300K, the temperature increases 15 times, and the pressure also increases 15 times (for example, to about 15 MPa). However, since the superconducting coil 12 does not operate at room temperature, the electromagnetic force 50 does not act on the coil reinforcement case 14.

After all, according to the inventor's calculations, when the coil reinforcement case 14 is designed to withstand the electromagnetic force 50 and the pressure of the cooling gas 16 at extremely low temperatures, in most cases it can also withstand the pressure of the cooling gas 16 that is elevated at room temperature. There is no need to make the thickness of the coil reinforcement case 14 excessively large in consideration of the fairly high pressure of the cooling gas 16 at room temperature. Therefore, it is realistically possible to design the coil reinforcement case 14 to have the two roles of providing a reinforcing structure for the superconducting coil 12 and ensuring the airtightness of the cooling gas 16.

As described above, the superconducting coil device 10 according to the embodiment includes a coil reinforcing case 14 that hermetically contains the cooling gas 16 together with the superconducting coil 12 and surrounds the superconducting coil 12 to reinforce the superconducting coil 12. In this way, the cooling gas 16 filled in the superconducting coil device 10 can promote uniform heat conduction inside the superconducting coil 12. This improves the thermal stability of the superconducting coil 12 and the superconducting coil device 10. In addition, since reinforcement and airtightness can be achieved with a single coil reinforcing case 14, the number of parts is reduced and manufacturing costs are reduced. There is no need for a dual structure, such as a frame structure that reinforces the superconducting coil 12 and a pressure vessel that surrounds it.

Figure 5 is a diagram showing a schematic diagram of a modified coil reinforcement case 14. The coil reinforcement case 14 may include an inner case frame 14d in addition to the outer case frame 14a, the upper case plate 14b, and the lower case plate 14c. The inner case frame 14d is disposed adjacent to the inner circumferential surface of the superconducting coil 12 and is hermetically joined to the upper case plate 14b and the lower case plate 14c. Because the inner case frame 14d is provided, the coil reinforcement case 14 can more firmly reinforce the superconducting coil 12.

In this case, the coil reinforcing case 14 may be doughnut-shaped with an opening in the center, similar to the superconducting coil 12. The upper case plate 14b and the lower case plate 14c may be doughnut-shaped plates.

The case inner frame 14d may be applied to the cylindrical or box-shaped coil reinforcement case 14 shown in FIG. 4, i.e., may be installed inside the coil reinforcement case 14.

Figure 6 is a schematic diagram of a current lead section 20 according to an embodiment that can be applied to the superconducting coil device 10 shown in Figure 1. The current lead section 20 includes a superconducting current lead 60 and a metal current lead 62. The superconducting current lead 60 is connected to the superconducting coil 12, and the metal current lead 62 is connected to the superconducting current lead 60. That is, the metal current lead 62 is connected to the superconducting coil 12 via the superconducting current lead 60.

The superconducting current lead 60 may be, for example, a REBCO wire, or may be formed of a copper oxide superconductor or other high temperature superconducting material. Alternatively, the superconducting current lead 60 may be formed of a low temperature superconducting material, such as NbTi. The metal current lead 62 is formed of a metal material with excellent electrical conductivity, such as pure copper, such as oxygen-free copper.

The superconducting current lead 60 is housed in the coil reinforcement case 14, while the metal current lead 62 is attached to the coil reinforcement case 14 so as to seal the cooling gas 16. A hermetic seal 64 forming a part of the metal current lead 62 is formed at the boundary between the superconducting current lead 60 and the metal current lead 62, and this hermetic seal 64 is hermetically joined to the coil reinforcement case 14. The metal current lead 62 forms an airtight feed-through structure in the coil reinforcement case 14. The coil reinforcement case 14 may include a case body 66 arranged to surround the superconducting coil 12 so as to reinforce the superconducting coil 12, and a tube portion 68 extending from the case body 66 to the hermetic seal portion 64 so as to surround the superconducting current lead 60. The tube portion 68 is hermetically joined to the hermetic seal portion 64.

As described above, the coil reinforcement case 14 is thermally coupled to the second cooling stage of the cryogenic refrigerator and can be cooled to the cooling temperature of the second cooling stage. The hermetic sealing portion 64 is thermally coupled to the first cooling stage of the cryogenic refrigerator and can be cooled to the cooling temperature of the first cooling stage.

As in this embodiment, if the superconducting current lead 60 is housed in the coil reinforcement case 14, there is no need to provide an airtight feed-through structure for the superconducting current lead 60 in the coil reinforcement case 14. This configuration is advantageous because it makes it easier to implement the current lead portion 20 in the superconducting coil device 10.

In addition, since the metal current lead 62 is connected to the high temperature part (room temperature part), it becomes a path for heat to penetrate into the low temperature part (superconducting current lead 60, superconducting coil 12). If the metal current lead 62 is placed inside the coil reinforcement case 14, heat transfer from the metal current lead 62 to the cooling gas 16 inside the coil reinforcement case 14 may cause convection in the cooling gas 16, increasing the amount of heat that penetrates. However, as shown in FIG. 6, an airtight seal 64 is formed at the boundary between the superconducting current lead 60 and the metal current lead 62, and the metal current lead 62 is outside the coil reinforcement case 14, so that the heat input from the metal current lead 62 into the coil reinforcement case 14 can be reduced.

In addition, at least a portion of the metal current lead 62 may extend from the hermetic sealing portion 64 into the coil reinforcement case 14, and the boundary between the superconducting current lead 60 and the metal current lead 62 may be positioned within the coil reinforcement case 14.

Figures 7(a) and 7(b) are schematic diagrams illustrating a variation of the embodiment of Figure 6. As with the embodiment of Figure 6, the current lead portion 20 comprises a superconducting current lead 60 and a metal current lead 62. A hermetic seal 64, which forms part of the metal current lead 62, is formed at the interface between the superconducting current lead 60 and the metal current lead 62.

As shown in FIG. 7(a), the superconducting coil device 10 may include a coil case 70 that hermetically accommodates the cooling gas 16 together with the superconducting coil 12, and a coil reinforcement structure 72 that is arranged to surround the superconducting coil 12 so as to reinforce the superconducting coil 12. The hermetic sealing portion 64 is hermetically joined to the coil case 70. The coil reinforcement structure 72 is arranged inside the coil case 70. As in the above-described embodiment, the coil reinforcement structure 72 may include an outer frame, an upper plate, and a lower plate that are configured to suppress deformation of the superconducting coil 12 due to electromagnetic forces acting radially on the coil during excitation of the superconducting coil 12. However, the coil reinforcement structure 72 does not need to be airtight. In this way, the superconducting coil device 10 may include the coil case 70 and the coil reinforcement structure 72 as separate components.

As shown in FIG. 7(b), the superconducting coil device 10 includes a coil case 70 that hermetically contains the cooling gas 16 together with the superconducting coil 12, but the superconducting coil 12 does not necessarily need to be provided with a coil reinforcement structure.

The present invention has been described above based on examples. Those skilled in the art will understand that the present invention is not limited to the above-described embodiments, and that various design changes and modifications are possible, and that such modifications are also within the scope of the present invention. Various features described in relation to one embodiment can also be applied to other embodiments. A new embodiment resulting from a combination will have the combined effects of each of the combined embodiments.

In the above embodiment, the superconducting coil 12 is a single pancake coil formed from high-temperature superconducting wire 40, but the superconducting coil 12 that can be applied to the superconducting coil device 10 according to the embodiment is not limited to those having such a specific shape and material. For example, the superconducting coil 12 may be a double pancake coil or other multi-layer pancake coil. The superconducting coil 12 may be a superconducting coil formed by winding wire in a solenoid shape. The superconducting coil 12 may be a low-temperature superconducting coil formed from low-temperature superconducting wire. The coil reinforcing case 14 may be designed to fit these various superconducting coils 12.

The present invention has been described using specific terms based on the embodiment, but the embodiment merely illustrates one aspect of the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiment without departing from the concept of the present invention as defined in the claims.

10 Superconducting coil device, 12 Superconducting coil, 14 Coil reinforcement case, 14a Case outer frame, 14b Case upper plate, 14c Case lower plate, 16 Cooling gas, 32 Cryogenic refrigerator, 60 Superconducting current lead, 62 Metal current lead.

Claims (5)

A superconducting coil;
a coil reinforcement case including a case outer frame disposed adjacent to an outer peripheral surface of the superconducting coil, an upper case plate disposed adjacent to an upper end surface of the superconducting coil and airtightly joined to the case outer frame, and a lower case plate disposed adjacent to a lower end surface of the superconducting coil and airtightly joined to the case outer frame, the coil reinforcement case being disposed surrounding the superconducting coil to reinforce the superconducting coil and airtightly accommodating a cooling gas together with the superconducting coil;
a heat transfer plate attached to an outer surface of the coil reinforcement case,
A superconducting coil device characterized in that the coil reinforcement case is thermally coupled to a cryogenic refrigerator outside the coil reinforcement case via the heat transfer plate , and the superconducting coil is cooled by the cryogenic refrigerator via the coil reinforcement case and the cooling gas. a superconducting current lead connected to the superconducting coil and housed in the coil reinforcement case; and a metal current lead connected to the superconducting current lead,
2. The superconducting coil device according to claim 1, wherein the metal current lead is attached to the coil reinforcement case so as to seal the cooling gas. The superconducting coil device according to claim 1 or 2, characterized in that the superconducting coil is formed by winding superconducting wires, and there is no impregnating material between the superconducting wires. The superconducting coil device according to any one of claims 1 to 3, characterized in that the superconducting coil is formed by winding a superconducting wire, and the cooling gas fills the gaps between the superconducting wires. 5. The superconducting coil device according to claim 1, wherein the heat transfer plate is thermally coupled to the cryogenic refrigerator via a flexible heat transfer member.

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