JPH10275945A - Superconductive coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive coil device where a coil winding can be constituted by an oxide superconductive wire with a large anisotropic property of magnetic field characteristics and the device can be miniaturized. SOLUTION: A device has a superconductive coil body 10 that is formed by an oxide superconductive wire and a superconductive magnetic shield body 13 that is arranged concentrically to the superconductive coil body 10 and shields a magnetic field constituent in the radius direction of a coil being applied to the superconductive coil body 10. The superconductive magnetic shield body 13 is constituted of a first magnetic shield body with a cutting being extended toward the axial direction, at least, at one portion of a circumferential direction and a second magnetic shield body being arranged so that the cutting of the first magnetic shield body can be covered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting coil device in which a superconducting coil body is formed by an oxide superconducting wire.

[0002]

2. Description of the Related Art As is well known, a metal-based superconducting wire represented by Nb-Ti has no anisotropy in magnetic field characteristics. For this reason,
When designing a coil using a metal-based superconducting wire, it is sufficient to consider only the scalar of the magnetic field applied to the wire.

[0003] However, high-temperature superconducting wires, which have recently attracted attention, ie, oxide superconducting wires represented by yttrium-based, bismuth-based, and thallium-based materials, have large anisotropy in magnetic field characteristics. For example, taking a bismuth-based tape-shaped oxide superconducting wire covered with a silver sheath as an example, FIG.
As shown in the above, there is a large difference in the critical current value of the wire between the case where the magnetic field is applied perpendicular to the tape surface and the case where the magnetic field is applied parallel to the tape surface, as shown in the above.
As shown in this figure, when a magnetic field is applied perpendicular to the tape surface, even a very weak magnetic field of 0.2 to 0.3 Tesla has a large effect on the critical current value. For this reason, as shown in FIG. 8, when it is attempted to obtain a superconducting coil device 2 capable of generating a Tesla-class large magnetic field by forming a winding with a tape-shaped oxide superconducting wire 1, In order to increase the current value, a large amount of the oxide superconducting wire 1 is required, and there is a problem that it is difficult to realize compactness, which is one of the important features of the superconducting coil device.

[0004]

As described above, in the conventional superconducting coil device in which the winding is formed by the oxide superconducting wire, a problem inherent to the oxide superconducting wire, that is, a difference in magnetic field characteristics, is encountered. It was difficult to achieve compactness due to the large anisotropy. Therefore, the present invention, the winding is constituted by an oxide superconducting wire having a large anisotropy of magnetic field characteristics,
Moreover, it is an object of the present invention to provide a superconducting coil device that can be made compact.

[0005]

In order to achieve the above object, a superconducting coil device according to the present invention comprises a superconducting coil body formed of an oxide superconducting wire and a concentrically arranged superconducting coil body. And a superconducting magnetic shield that shields a coil radial magnetic field component applied to the superconducting coil main body.

The superconducting coil main body may include a plurality of winding layers arranged concentrically, and the superconducting magnetic shield may be provided between the winding layers. The superconducting magnetic shield includes a first magnetic shield having at least one circumferentially extending notch extending in the axial direction or a non-shielding effect region including a portion having a superconducting characteristic weaker than the periphery. And a second magnetic shield provided to cover the non-shield effect region of the first magnetic shield.

Further, the superconducting magnetic shield may be formed in a cylindrical shape by arranging a plurality of superconducting thin plates in such a manner that adjacent ones in the circumferential direction overlap each other. Furthermore, the superconducting magnetic shield may be formed in a cylindrical shape by superposing one superconducting thin plate at the circumferential end.

[0008] In the superconducting coil device configured as described above, the superconducting magnetic shield body shields and reduces the coil radial magnetic field component (magnetic field component applied perpendicular to the wire tape surface) applied to the superconducting coil body. It becomes possible. At this time, the coil axial direction magnetic field component is not shielded by providing a notch in the superconducting magnetic shield body in the axial direction, or by providing a portion of the superconducting magnetic shield body with a weaker superconducting characteristic than the surroundings in the axial direction. can do.

As described above, since the radial magnetic field component applied to the superconducting coil main body can be reduced, the critical current value of the oxide superconducting wire can be improved, and as a result, the oxide superconducting wire can be improved. Can be effectively brought out, and the entire device can be made compact.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of a main part of a superconducting coil device according to one embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes a superconducting coil main body. The superconducting coil main body 10 includes an inner layer coil 11 and an outer layer coil 12 which are arranged concentrically and connected so that the directions of generation of magnetic fields are the same. These inner layer coil 11 and outer layer coil 12
Is composed of, for example, a bismuth-based tape-shaped wire covered with a silver sheath, that is, a tape-shaped oxide superconducting wire having a critical temperature of 100 K or more, wound so that the tape surface is parallel to the coil axis. Have been.

In this example, the inner layer coil 1
Superconducting magnetic shield 13 between coil 1 and outer coil 12
Is installed. The superconducting magnetic shield 13 is formed of a bismuth-based oxide superconductor plate and formed in a cylindrical shape having an axial length that can completely cover the inner peripheral surface of the outer coil 12 having a long axial length. Specifically, as shown in FIG. 2A, a first magnetic shield body 15 having a notch (slit) 14 extending in the axial direction at at least one position in the circumferential direction, and FIG. And a second magnetic shield 16 disposed so as to cover the cutout 14 of the first magnetic shield 15 from outside (or inside).

The superconducting coil device configured as described above is used in a state where the entire element shown in FIG. 1 is immersed in liquid nitrogen or in a state where the entire element is directly cooled to a liquid nitrogen temperature level by a refrigerator. .

As described above, the superconducting magnetic shield 1 is concentric with the superconducting coil device 10 formed of an oxide superconducting wire, specifically, between the inner coil 11 and the outer coil 12.
3 are provided. Therefore, the shielding effect of the superconducting magnetic shield 13 can reduce the coil radial magnetic field component applied to the superconducting coil main body 10 by shielding. For this reason, the critical current value of the oxide superconducting wire can be improved, and as a result, the characteristics of the oxide superconducting wire can be effectively extracted, and the overall device can be made compact.

The notch 14 provided in the first magnetic shield 15 is necessary in order not to shield the axial magnetic field. Although only the first magnetic shield 15 can reduce the coil radial magnetic field component applied to the superconducting coil main body 10, the cut 14
Is a non-shield effect area, and there is a possibility that a magnetic field component in the coil radial direction may enter from this area. Therefore, it is desirable to provide the second magnetic shield 16 so as to cover the cut 14 as in this example. Further, instead of the cut 14, a portion having superconductivity lower than that of the periphery may be provided in the axial direction. It is desirable that the non-shielding effect region formed by such a cut or a portion having a weak superconducting property penetrates the superconducting magnetic shield body in the axial direction, but does not necessarily have to penetrate.

FIG. 3 is a schematic longitudinal sectional view of a main part of a superconducting coil device according to another embodiment of the present invention. In this figure, the same functional parts as those in FIG. 1 are indicated by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.

The superconducting coil device according to this embodiment differs from that shown in FIG. 1 in the configuration of the superconducting shield 13a. That is, the superconducting shield 13 according to this example
As shown in FIG. 4, a is formed in a tubular shape by arranging a plurality of bismuth-based oxide superconductor thin plates 17 in such a manner that adjacent thin plates 17 in the circumferential direction overlap each other. .

Even if such a superconducting shield 13a is incorporated, the same effect as in the above example can be exerted. Particularly, in this example, not only can the magnetic field in the coil radial direction be efficiently shielded without reducing the magnetic field component in the axial direction of the superconducting coil body 10 as much as possible, but also when an AC magnetic field is applied to the superconducting magnetic shield 13a, for example, For example, when the coil body 10 is an AC coil, it is possible to reduce the AC loss in the superconducting magnetic shield 13a.

It should be noted that the present invention is not limited to the above examples, but can be implemented with various modifications. For example, as shown in FIG. 5, if the superconducting magnetic shield 13b having a radial thickness corresponding to the scalar amount of the coil radial magnetic field component applied to each part of the superconducting coil main body 10 is incorporated, the object can be achieved more efficiently. can do. Also, as shown in FIG. 6, a superconducting shield 1 formed in a cylindrical shape by superposing one superconducting thin plate at the circumferential end.
3c may be used.

[0020]

As described above, according to the present invention,
It is possible to effectively suppress the anisotropy of the magnetic characteristics inherent to the oxide superconducting wire, thereby effectively extracting the features of the oxide superconducting wire and contributing to the realization of a compact device as a whole.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a main part of a superconducting coil device according to an embodiment of the present invention.

FIG. 2A is a perspective view of a first shield constituting a superconducting magnetic shield incorporated in the apparatus.
(B) End view of the superconducting magnetic shield

FIG. 3 is a schematic longitudinal sectional view of a main part of a superconducting coil device according to another embodiment of the present invention.

FIG. 4 is an end view of a superconducting magnetic shield incorporated in the apparatus.

FIG. 5 is a schematic longitudinal sectional view of a main part of a superconducting coil device according to still another embodiment of the present invention.

FIG. 6 is an end view of a modification of the superconducting magnetic shield.

FIG. 7 is a diagram for explaining a problem when a superconducting coil is formed by an oxide superconducting wire;

FIG. 8 is a diagram for explaining a problem when a superconducting coil is formed by an oxide superconducting wire;

DESCRIPTION OF SYMBOLS 10 ... Superconducting coil device 11 ... Inner layer coil 12 ... Outer layer coil 13, 13a, 13b, 13c ... Superconducting magnetic shield 14 ... Cut 15 ... First magnetic shield 16 ... Second magnetic shield 17 ... Oxide superconducting thin plate

Claims (5)

[Claims] 1. A superconducting coil main body formed of an oxide superconducting wire, and a superconducting magnetic shield disposed concentrically with respect to the superconducting coil main body to shield a coil radial magnetic field component applied to the superconducting coil main body. A superconducting coil device comprising a body. 2. The superconducting coil body according to claim 1, wherein said superconducting coil body has a plurality of winding layers arranged concentrically, and said superconducting magnetic shield is provided between said winding layers. The superconducting coil device as described in the above. 3. A superconducting magnetic shield, comprising: a first magnetic shield having at least one circumferentially extending notch extending in the axial direction or a non-shielding effect region comprising a portion having a superconducting characteristic weaker than the surroundings; 3. The superconducting coil device according to claim 1, further comprising a second magnetic shield provided so as to cover the non-shield effect region of the first magnetic shield. 4. 4. The superconducting magnetic shield body is formed in a cylindrical shape by arranging a plurality of superconducting thin plates so that adjacent ones in a circumferential direction overlap each other. Or the superconducting coil device according to 2. 5. The superconducting coil according to claim 1, wherein the superconducting magnetic shield is formed in a cylindrical shape by superimposing one superconducting thin plate at circumferential ends. apparatus.