JPS6074605A - Superconducting magnet - Google Patents

Abstract

PURPOSE:To eliminate generation of bending stress or sheering stress of a superconductor due to stress of a spacer between turns by making the length of conductor winding direction of the spacer between turns longer than the interval between the spacers and providing a notch on the part of the spacer to reduce the rate of the spacers. CONSTITUTION:A superconductor 3 is wound concentrically a required number of times and plural number of spacers 21 between turns inserted between the conductors are made the length l of conductor winding directon longer than the interval p of the spacer and a part of the spacer is removed to make a U-shape. The spacer is inserted at the interval p while the conductor is wound and the spacer 21 between turns inserted between the inner conductors 3 and the spacer 21 inserted between the outer conductors 3 overlap at both the ends of conductor winding direction in their relative positions. This eliminates generation bending stress or sheering stress of the inner superconductor 3 when the spacers 21 are inserted between the outer turns of the conductor while the superconductor 3 is wound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting magnet used in a nuclear fusion device or the like, and particularly relates to an improvement in a spacer forming a flow path for cooling a superconducting magnet body.

[Technical background of the invention]

In recent years, devices that utilize superconductivity have been widely adopted, including magnetic levitation trains, energy storage, rotating electric machines, and nuclear fusion devices. In particular, nuclear fusion devices are becoming significantly larger as they move toward practical use, making it essential to develop large superconducting magnets for use in these devices.

Generally, in order to create a superconducting state, it is necessary to cool a magnet body made of superconducting wire to an extremely low temperature using a coolant such as liquid helium or superconducting helium. For this reason, the superconducting magnet body is usually housed in a vacuum-insulated container.

By the way, conventional superconducting magnets are made by winding a superconducting conductor a predetermined number of times and inserting a plurality of inter-turn spacers at appropriate intervals between each conductor to form a unit coil. A superconducting magnet body is constructed by laminating the individual layers in the axial direction and inserting a plurality of interlayer spacers at appropriate intervals between the laminated layers, and the superconducting magnet body is placed in a vacuum-insulated cryogenic container. Some are designed to be stored together with a refrigerant such as liquid sutosuumu.

FIGS. 1 to 3 each show the state of the forming process of a unit coil, which is a basic component of such a superconducting magnet. That is, as shown in FIGS. 1 to 3, a plurality of inter-turn spacers 2 are arranged at appropriate intervals on the outer peripheral surface of a winding frame 1, and a strip-shaped superconducting conductor 3 is placed on the outer peripheral surface of the winding frame 1. 1 is wound in the direction of the arrow shown in the figure, and then, with the superconducting conductor 3 in tension, inter-turn spacers 2 similar to those described above are sequentially inserted, and the winding frame 1 is rotated to create a space between turns between each conductor. A unit coil 4 with a spacer inserted therein is molded.

The inter-turn spacer 2 interposed between each conductor of the unit coil 4 serves to provide electrical insulation between each conductor, support against electromagnetic force, and form a coolant flow path for liquid helium or the like to cool the superconducting conductor 3.

Therefore, in order to improve the supporting characteristics against electromagnetic force, it is sufficient to increase the spacer ratio (the ratio of the surface area in the turn direction of the inter-turn spacer 2 to the surface area in the turn direction of the superconducting conductor 3), but in order to operate the superconducting magnet stably, It is necessary to reduce the spacer ratio and provide sufficient cooling channels. Therefore, the spacer ratio is usually set to 50 inches or less.

[Problems with background technology]

However, in this way, spacers 2 between turns are placed between each superconducting conductor 3 of a unit coil 4 so that the spacer ratio is 50 inches or less.
As is clear from Fig. 2, the spacer spacing is large relative to the length of the inter-turn spacer 2 in the conductor winding direction, and the spacer placement position between each turn may be on the same line in the radial direction. Because the superconducting conductor 3 is not aligned, the winding of the superconducting conductor 3 sometimes results in applying bending stress and shearing stress to the superconducting conductor 3 inside when the inter-turn spacer 2 inserted between the turns is strongly pressed. For this reason,
Not only does the insulation property of the superconducting conductor 3 deteriorate, but in extreme cases, the inner superconducting conductor 3 falls between the spacers as shown by the dotted line in FIG. 3, resulting in defects such as poor insulation between turns. Ta.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks, and its purpose is to reduce the bending stress and shear of the superconducting conductor due to the pressing force of the inter-turn spacer inserted between the superconducting conductors even if the spacer ratio of the unit coil is reduced. It is an object of the present invention to provide a superconducting magnet that is robust and has excellent characteristics and can eliminate the generation of stress.

[Summary of the invention]

In order to achieve this object, the present invention uses a unit coil as a basic component, which is formed by winding a superconducting conductor concentrically a predetermined number of times and inserting a plurality of inter-turn spacers at appropriate intervals between each conductor. In a superconducting magnet whose main body is housed in a vacuum-insulated container together with a refrigerant such as a liquid (MIJ), the conductor winding direction of the inter-turn spacer inserted between each superconducting conductor constituting the unit coil is It is characterized in that the length is longer than the spacer interval and a notch is provided in a part of the spacer to reduce the spacer ratio.

[Embodiments of the invention]

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

FIG. 4 shows an example of a partial configuration of a unit coil which is a basic component of the superconducting magnet according to the present invention.The forming means thereof are the same as in the case of FIG. Let's talk about. That is, in this example, FIG. 4(a).

As shown in (b), a superconducting conductor 3 is wound concentrically a predetermined number of times, and a plurality of inter-turn spacers 21 are inserted between each conductor, the spacer length l in the conductor winding direction.
is larger than the spacer interval p (l!>p), and a part thereof is cut out to form a U-shaped spacer.

Therefore, by winding the superconducting conductor 3 and inserting the U-shaped inter-turn spacer 21 having the spacer length as shown in FIG. The inter-turn spacer 21 inserted between the inner superconducting conductor 3 and the outer superconducting conductor 3
The inter-turns 21 inserted therebetween are in a positional relationship such that both ends in the conductor winding direction overlap. Therefore, when the superconducting conductor 30 is wound, even if the outer inter-turn spacer 21 is pressed, bending stress or shearing stress is not generated in the inner superconducting conductor 3, and this superconducting conductor 3 is Since it does not fall between the spacers, the insulation properties between the turns are not impaired. In addition, if the spacer length l is simply made thicker than the spacer interval p (/>p), the spacer ratio will be 50% or more, resulting in poor cooling efficiency, but in this example, the rectangular spacer Since a portion of the spacer is cut out to form a U-shape so that the spacer ratio is 50 or less, a sufficient cooling flow path can be secured and cooling efficiency can be improved.

In the above embodiment, a case was described in which a U-shaped spacer was used as the inter-turn spacer 2.
Of course, as shown in h), a part of the rectangular spacer may be cut out to form an inter-turn spacer having the shape shown in the figure. In short, any shape may be used as long as the length l of the spacer in the conductor winding direction is greater than the length of the spacer interval p, and the spacer ratio can be reduced to 50 inches or less by cutting out a part of the spacer.

〔Effect of the invention〕

As described above, according to the present invention, even if the spacer ratio of the unit coil is lowered, the bending stress and shear stress of the superconducting conductor due to the pressing force of the inter-turn spacer inserted between the superconducting conductors can be eliminated. Moreover, a superconducting magnet with excellent characteristics can be provided.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of the structure of a unit coil, which is a basic component of a conventional superconducting magnet, and its forming process, and FIGS. 4(a) and 4(b) are unit coils in an embodiment of the present invention. A configuration explanatory diagram showing a part of the
) are plan views showing examples of different shapes of inter-turn spacers used in the present invention. 1... Winding frame, 21... Spacer between turns, 3...
Superconducting conductor, 4... unit coil. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 4 (α) Figure 5 Layer 1 door/f

Claims (1)

[Claims] A superconducting magnet main body is constructed using a unit coil as a basic component, which is formed by winding a superconductor concentrically a predetermined number of times and inserting a plurality of inter-turn spacers at appropriate intervals between each conductor, and this superconducting magnet In a superconducting magnet whose main body is housed together with a coolant such as liquid helium in a vacuum-insulated container, the length of the inter-turn spacer inserted into the superconducting conductor constituting the unit coil in the conductor winding direction is longer than the spacer interval, and A superconducting magnet characterized in that a notch is provided in a part of the spacer to reduce the spacer ratio.