JPH0727816B2 - Superconducting coil - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting coil, and more particularly to a superconducting coil in which a coil formed by winding a superconducting conductor is supported by an inner support and an outer support. .

[Background of the Invention]

Usually, there are various types of superconducting coils depending on the cooling method, but generally, they are roughly classified into those containing the coil in a helium container, the inside of the coil is a bobbin that also serves as a winding frame, and the outside Is divided into two, one with a support tube.

In either case, some support exists on the inner diameter side and the outer diameter side of the coil.

A device for accommodating this type of superconducting coil is disclosed in JP-A-59-191308.

However, conventionally, since the inner support material and the outer support material are completely the same, the coil cannot be supported from the inner cylinder during cooling. Further, there is a defect that a gap is formed between the outer cylinder and the coil, the coil is not sufficiently supported, and the coil moves during excitation.

[Object of the Invention]

The present invention has been made in view of the above points, and an object thereof is to reduce the stress that is mechanically generated during coil excitation, and to increase the cooling efficiency of the coil thermally. It is to provide a stable superconducting coil with excellent performance.

[Outline of Invention]

According to the present invention, a coil formed by winding a superconducting conductor is dipped in liquid helium and housed and supported in a helium container composed of an inner cylinder and an outer cylinder. By forming the cylinder with a material having a heat shrinkage ratio higher than that of the cylinder, the intended purpose is achieved.

That is, by appropriately disposing at least two kinds of materials having different mechanical strengths, heat shrinkage characteristics, etc., the stress of the coil at the time of excitation is relaxed, and the cooling efficiency is also improved thermally.

Example of Invention

 Hereinafter, the present invention will be described based on embodiments of the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a superconducting coil, 2 is a helium container that houses the superconducting coil 1, 3 is a liquid nitrogen shield that thermally shields the surroundings, 4
Is a heat insulating vacuum container for accommodating all of them, and 5 is a support 5 for supporting the helium container 2 from the heat insulating vacuum container 4.

In this embodiment, the inner cylinder 2 and the outer cylinder 7 of the helium container 2 are made of different materials. In this case, the inner cylinder 6, the superconducting coil 1,
When the heat shrinkage rates of the outer cylinder 7 are α ₁ , α ₂ , and α ₃ , respectively, α ₁ <α ₂ <α ₃ is selected. As an example, when the superconducting coil 1 is mainly composed of copper,
A method of using SUS material and aluminum for the outer cylinder 7 can be considered.

When the coil is cooled in this state, the internal pressure is applied to the coil from the inner cylinder side and the external pressure is applied to the coil from the outer cylinder side due to the difference in the thermal contraction rate. That is, the residual compressive force is applied in the radial direction. This state is a state in which the coil is mechanically well fixed, and suppresses the movement of the coil during the subsequent excitation. In other words, by suppressing the coil movement, the generation of frictional heat can be prevented, and the thermal characteristics can be made excellent.

Further, during excitation, a hoop stress is generated in the coil, which is a tensile stress with respect to the superconducting conductor and is reduced by the residual compressive force during cooling. As a result, the stress in the superconducting conductor is reduced. Go down.

In this way, it is possible to provide a superconducting coil having improved performance both mechanically and thermally.

〔The invention's effect〕

According to the superconducting coil of the present invention described above, a coil formed by winding a superconducting conductor is immersed and supported in a helium container composed of an inner cylinder and an outer cylinder by being immersed in liquid helium. Since the outer cylinder of the container is formed of a material having a heat shrinkage ratio higher than that of the inner cylinder, the residual compressive stress from the inner and outer cylinders of the helium container can be applied to the superconducting coil during cooling, and the coil during excitation It is possible to achieve a remarkable effect on the performance both mechanically and thermally, such that the stress of 1 is relaxed and the cooling efficiency is increased.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the superconducting coil of the present invention. 1 ... Superconducting coil, 2 ... Helium container, 3 ... Liquid nitrogen shield, 4 ... Adiabatic vacuum container, 5 ... Support,
6 ... Inner cylinder of helium container, 7 ... Outer cylinder of helium container.

Claims (1)

[Claims] 1. A superconducting coil, comprising: a coil formed by winding a superconducting conductor; an inner support for supporting the coil from the inside; and an outer support for supporting the coil from the outside, wherein the coil is liquid helium. Superconducting method, characterized in that the outer cylinder of the helium container is made of a material having a heat shrinkage ratio higher than that of the inner cylinder. coil.