JPS5873104A - Superconductive magnet - Google Patents

Abstract

PURPOSE:To obtain a compact and stable superconductive magnet by a method wherein insulating materials are fixed to the circumference of compound superconductive conductors and lubricating materials are applied to the outsides of the insulating materials or low friction spacers are positioned for winding. CONSTITUTION:In layers composed by winding compound superconductors, interlayer insulating materials 3, such as glass fiber inserted epoxy resin, cloth inserted phenol resin, are buried in and fixed to the suitable places at the layer sides of stabilizing materials 2 and spacers 4 are inserted and positioned between the spaces facing these interlayer insulating materials 3. Electromagnetic force acting on the layers is transferred to the conductors through the interlayer insulating materials 3 and the spacers 4. Meanwhile, in the spaces between conductor turns, interturn insulating materials 5 are fixed to the insides of the turns of the stabilizing materials 2 and spacers 6 such as ethylene tetrafluoride having low friction coefficient are inserted and positioned at the middle of the interturn insulating materials 5. This does not generate friction heat involved in conductor transition on the surfaces of the conductors and a compact and stable magnet can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a nine-superconducting magnet using a superconductor.

Conventionally, there were four points in the practical application of superconducting magnets.
One of the issues is the stability of the conductor. In other words, the current value that can be passed when a superconducting conductor is wound and used as a magnet does not necessarily match the characteristics of the superconducting conductor itself, and the superconductor often breaks down at low current values. One possibility is that the electromagnetic force exerted on the conductor itself causes the conductor to displace itself, and the energy released heats the conductor above the critical temperature needed to maintain it as a superconductor. Therefore, even if the superconductor were to break, a large amount of copper or aluminum was placed around the superconductor in order to keep the Joule loss low enough to justify cooling.
A composite superconducting conductor with a stabilizing material made of Ni is used.

Such a conductor generally has the disadvantage that the cross-sectional area of the stabilizing material becomes large, which reduces the current density of the magnet as a whole and increases the cost.

The present invention was made to improve the above drawbacks, and
To provide a compact and stable superconducting magnet, an electrical insulating material is fixed around a composite superconducting conductor, and a lubricant is applied to the outside of the insulating material or a low-friction spacer is placed. It is characterized in that it is wound so that no frictional heat is generated on the surface of the conductor due to the displacement of the conductor.

An embodiment of the superconducting magnet of the present invention is shown in FIG. 1 below. The superconducting conductor 1 mainly consists of a large number of thin superconducting wires, and a copper or aluminum alloy superconducting conductor is formed around the superconducting conductor 1. In the glabella formed by winding such a composite superconducting conductor, an interlayer insulating material 3 is embedded and fixed at an appropriate location on the interlayer side of the stabilizing material 2, and a spacer 4 is placed between the interlayer insulating materials 3.3 facing each other. Insert is placed. The electromagnetic force acting between the layers is transmitted to the conductor via the interlayer insulating material 3 and the spacer 4. The interlayer portions where there is no insulating material are filled with liquid helium as a coolant. on the other hand,
Between the conductor turns, an inter-turn insulating material 5 is fixed to the inside of the turn of the stable conductor material 2, and a spacer 6 is inserted between the turn-related insulating materials 5,5. As the interlayer insulation material 3 and the interturn insulation material 5, electrical insulation materials such as glass fiber-containing epoxy resin, cloth-containing diphenol resin, and polyelectrode resin are suitable. These are fixed to the stabilizing material by means such as adhesion or embedding. In addition, as the spacer 6, tetrafluoroethylene, etc., which has a low coefficient of friction, is suitable.
The surface of the above-mentioned epoxy resin or the like may be coated with lubricating ethylene tetrafluoride or molybdenum disulfide.

In such a configuration, even if the composite superconducting conductor is displaced due to external force such as electromagnetic force, the interface between the stabilizing material 2 and the insulating materials 3 and 5 will also be affected by the insulating materials 3 and 5 and the spacer 4. Slippage occurs at the interfaces of 6 and 6. The heat generated as a result is transferred to the stabilizing material 2 through the insulating materials 3 and 5, but the thermal conductivity of the insulating materials 3 and 5 is less than 1/1000 compared to copper etc., so the heat propagation rate is is extremely slow.

If heat is generated on the surface of the stabilizing material 2, the heat will spread throughout the stabilizing material 2 almost instantaneously, and the temperature will also rise within a short period of time. On the other hand, when heat is transmitted to the stabilizing material 2 via the insulating materials 3 and 5, the speed of heat propagation is slow as described above, so it is not necessary to heat the stabilizing material 2. Since the coolant in contact with the stabilizing material 2 removes heat, the temperature rise of the stabilizing material 2 is suppressed sufficiently low and does not exceed the critical temperature. Since the coefficient of friction between and 6 is low, the amount of heat generated is also small.

FIG. 2 shows another embodiment of the invention. This is an example of forced cooling in which a cooling channel 7 is provided inside the stabilizing material 2, and supercritical pressure helium or two-phase helium flows therein. Therefore, the insulating material 8 is completely wrapped around the composite superconducting conductor. And spacer 4 between the layers. Inter-turn spacers 6 are arranged. In this case as well, the same effect as described in FIG. 1 is obtained.

Furthermore, the spacer described in the above embodiment may be omitted and ethylene tetrafluoride or molybdenum disulfide may be applied to the outside of the insulating material.

As described above, according to the present invention, heat propagation is slow and the temperature rise of the conductor can be suppressed to a very low level, so there is no need to apply a large amount of stabilizing material in case the conductor exceeds the critical temperature. , a small and compact superconducting magnet can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a main part showing one embodiment of a superconducting magnet of the present invention, and FIG. 2 is a sectional view of a main part showing another embodiment of a superconducting magnet of the present invention. DESCRIPTION OF SYMBOLS 1... Superconducting conductor, 2... Stabilizing material, 3... Interlayer insulation material, 4.6... Spacer, 5... Inter-tank insulation material, 7... Cooling channel.

Claims (1)

[Claims] An electrical insulating material is fixed around a composite superconducting conductor mainly composed of a superconducting conductor and a stabilizing material, and a lubricant is coated on the outside of the electrical insulating material or a low-friction spacer is arranged to wind the wire. A superconducting magnet that is characterized by: