JPH0464165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 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 that forms 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, such as magnetic levitation trains, energy storage, rotating electric machines, and nuclear fusion devices. In particular, nuclear fusion devices are significantly increasing in size 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 cryogenic container with vacuum insulation. Some are designed to be stored together with a refrigerant such as helium.

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 the winding frame 1, and a strip-shaped superconducting conductor 3 is placed on the outer peripheral surface of the winding frame 1.
Rotate in the direction of the arrow shown and wrap it around for one turn.
Next, with the superconducting conductor 3 in tension, the winding frame 1 is inserted while sequentially inserting the inter-turn spacers 2 similar to those described above.
By rotating the unit coil 4, a unit coil 4 with an inter-turn spacer inserted between each conductor is formed.

The inter-turn spacer 2 interposed between each conductor of the unit coil 4 is used 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, To achieve this, it is necessary to reduce the spacer ratio and provide sufficient cooling channels. Therefore, this spacer ratio is usually set to 50% or less.

[Problems with background technology]

However, when the inter-turn spacer 2 is interposed between each superconducting conductor 3 of the unit coil 4 so that the spacer ratio is 50% or less, as is clear from Fig. 2, the conductor winding of the inter-turn spacer 2 is Since the spacer interval is large relative to the length in the direction, and the spacer positions between each turn are not aligned in the same line in the radial direction, the inter-turn spacer 2 inserted between the turns when winding the superconducting conductor 3 is If it is strongly pressed, bending stress and shearing stress will be applied to the superconducting conductor 3 inside it.
For this reason, not only will the insulation properties of the superconducting conductor 3 deteriorate, but in extreme cases, the inner superconducting conductor 3 will fall between the spacers as shown by the dotted line in Figure 3, resulting in poor inter-turn insulation. There were flaws.

[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 in which a superconducting magnet main body is housed together with a coolant such as liquid helium in a vacuum-insulated container, the length in the conductor winding direction of the inter-turn spacer inserted between each superconducting conductor constituting the unit coil is defined as the spacer. It is characterized by being longer than the spacer and having a notch 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 embodiment, as shown in FIGS. 4a and 4b, a superconducting conductor 3 is wound concentrically a predetermined number of times, and a plurality of inter-turn spacers 21 are inserted between each of the conductors in the direction of conductor winding. The spacer length l is larger than the spacer interval p (l>p)
A part of the spacer is cut out to form a U-shaped spacer.

Therefore, by inserting the U-shaped inter-turn spacer 21 having such a spacer length while winding the superconducting conductor 3 with the spacer interval p as shown in the figure, the inner superconducting conductor The inter-turn spacer 21 inserted between the outer superconducting conductors 3 and the inter-turn spacer 21 inserted between the outer superconducting conductors 3 have a positional relationship such that both ends in the winding direction of the conductor overlap. Therefore, even if the outer inter-turn spacer 21 is pressed when the superconducting conductor 3 is wound, bending stress or shearing stress will not be generated in the inner superconducting conductor 3, and this superconducting conductor 3 will be able to move around the lower spacer. I don't get depressed in between,
The insulation properties between turns are not impaired. Furthermore, if the spacer length l is simply made larger than the spacer interval p (l>p), the spacer ratio will be more than 50%, resulting in poor cooling efficiency, but in this example, rectangular spacers are used. Since a portion 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 U-shaped spacer 21 is used as the inter-turn spacer 21, but as shown in FIG. Of course, this is a good thing. 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% 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 drawings]

FIGS. 1 to 3 are explanatory diagrams of the structure and forming process of a unit coil, which is a basic component of a conventional superconducting magnet, and FIGS. 4a and 4b show a part of a unit coil in an embodiment of the present invention. Configuration explanatory diagram shown, No. 5
Figures a to h 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.

Claims (1)

[Claims] 1. A superconducting magnet body is constructed with 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. In a superconducting magnet whose magnet body is housed in a vacuum-insulated container together with a coolant such as liquid helium, 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. A superconducting magnet characterized in that a notch is provided in a part of the spacer to reduce the spacer ratio.