JPS60937B2 - superconducting coil - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a superconducting coil, and in particular, it is made by winding a group of superconducting strands, each consisting of a large number of superconducting strands with a small cross-sectional size, in a groove provided in a coil holding member. This relates to a superconducting disk type superconducting coil.

Generally, superconducting coils are often used as devices that generate high magnetic fields, but unlike ordinary electromagnets, superconducting coils need to be cooled to extremely low temperatures, mainly liquid helium temperatures, and furthermore, superconducting coils have to be cooled to extremely low temperatures, mainly to the temperature of liquid helium. In particular, for large superconducting coils with magnetic field energies of gigajoules or more that are expected to be used in nuclear fusion devices, it is important to construct a support structure that can withstand the enormous electromagnetic force generated by the coils. It's becoming a problem.

Therefore, a superconducting coil having a structure as shown in FIG. 1 was considered as a prior art.

In this superconducting coil, a plate-shaped coil holding member 1 made of metal or an insulator is provided with a large number of coil grooves 2, and superconducting wires 3 are housed in the coil grooves 2. Incidentally, between the coil grooves 2 of the coil holding member 1, there are provided diagonally continuous rising grooves (not shown) for winding the superconducting wire 3 into the next turn. A predetermined number of superconducting wires 3 are assembled into the coil grooves 2 provided in the coil holding member 1 to form one superconducting disk 4. and,
A plurality of these superconducting disks 4 are attached to bolts 5 and nuts 6.
The superconducting coil 7 is assembled as a whole.
In the coil structure described above, the superconducting wire 3 is arranged as shown in FIG.

That is, FIG. 2 is a partially enlarged perspective view of the superconducting disk 4, in which the superconducting wire 3 is fixed in the coil groove 2 provided in the coil holding member 1 via the spacing member 3, and can be cooled all around. It looks like this. When the coil holding member 1 is made of metal, the spacing member 3 may be an insulating material or a metal whose surface has been subjected to insulation treatment, and when the coil holding member 1 is made of an insulating material, it may be an insulating material or a metal. By making the superconducting coil have the disk structure described above, it has become possible to sufficiently withstand the huge electromagnetic force generated by the superconducting coil. However, as superconducting coils become larger, the cross-sectional size of the wound superconducting wire 3 becomes larger. This is not possible. In large superconducting coils, a setting policy is usually adopted in which the coil operating current 1 is set to be equal to or less than the stabilizing current lr.

Therefore, the coil current 1 can be increased as lr is increased, and when the coil current 1 is increased, the coil current density also increases, making it possible to make the superconducting coil more compact, making the cryostat more compact, and further making the cooling system more compact. will also be connected. This stabilizing current lr■ is the cooling beam meter S (cm
), and there is a relationship between them as follows.

In view of the above points, this invention can withstand huge electromagnetic force.
Moreover, by increasing the number of cooling verimeters, the stabilizing current lr is increased, and the purpose is to provide a more compact superconducting coil.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, 9a, 9b, 9c, 9d'9e,...
is a superconducting wire, 9 is a superconducting strand group made up of a large number of these superconducting strands, and 4 is a superconducting wire group formed by winding these superconducting strands 9 into the coil groove 2 of the coil holding member 1. It is also a holding member that closes the entrance of the coil groove 2, and this serves to hold the superconducting wire group 9 in the coil groove 2, and at the same time Since the space between the superconducting wires 9a, 9b, . . . also serves as a cooling medium flow path through which the cooling medium flows, airtightness must be maintained between the coil holding material 1 and the holding member 10. By structuring the wire as described above, the cooling area that the superconducting wire receives can be significantly increased, and the stabilizing current lr can be increased by the relationship of the mth equation.

Therefore, the operating current can also be increased, and the size of the superconducting coil device that generates the same magnetic field in the same space should be smaller than the superconducting coil device shown in Figure 2, which is wound with the conventional type of superconducting wire 3. Note that the superconducting strands 9a, 9b, 9c, . . . may be either so-called bare wires without insulation treatment, or insulated wires.

Further, the superconducting wire group 9 may be of a twisted wire type as shown in FIG. 3, or may be of a braided wire type.
Further, since it is necessary to maintain airtightness between the presser material 1 and the coil holding member 1, metal is used and fixed to the coil holding member 1 by welding or the like.

At this time, the superconducting wires ga, gb...
・In the case of bare wires without insulation treatment, coil holding member 1
Also, it is necessary to insert an insulating layer between the holding material 10 and the superconducting wire group 9 to provide electrical insulation. Here, the cooling medium used may be a one-phase flow of liquid helium or a two-phase flow of liquid helium and helium gas.

As detailed above, ``In this invention, as the superconducting wire wound around the coil holding member, a group of superconducting strands made up of a large number of stranded or braided superconducting strands is used, so that each superconducting Cooling medium can now flow between the wires, improving the cooling verimer and making it possible to make superconducting coil devices more compact, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a superconducting coil having a prior art superconducting disk structure, FIG. 2 is a partially enlarged perspective view of FIG. 1, and FIG. 3 is a partially enlarged perspective view of an embodiment of the present invention. FIG. In the figure, 1 is a coil holding member, 2 is a coil groove, 3 is a conventional superconducting wire, 4 is a superconducting disk, 5 is a bolt, and 6
is a nut, 7 is the entire superconducting coil, 8 is a spacing member, ga
, 9b, gc... are superconducting wires, 9 is a group of superconducting wires, and 1 is a holding member. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A coil holding member in which a coil groove is formed, a group of superconducting strands inserted into the coil groove and formed into a bundle of multiple superconducting strands, and an opening of the coil groove airtightly closed to hold the superconducting element. A superconducting coil comprising a holding member that forms a cooling medium passage for circulating a cooling medium between the wires.