JPH09152089A - Very low temperature heat insulating pipe and superconductive cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain deterioration of heat insulating performance to be small even if bending, misalignment of inner and outer pipes, and the like are generated, by making the spiral directions of waving of the inner pipe and the outer pipe opposite to each other. SOLUTION: A spiral waved inner pipe 1 forming a refrigerant flow passage 3, and a spiral waved outer pipe 2 provided outside the inner pipe, are formed so that the spiral directions of waving are opposite to each other, and the gap between the inner pipe 1 and the outer pipe 2 is made vacuous so as to form a very low temperature heat insulating pipe. A superconductive cable core 5 is stored in the inner pipe 1 of very low temperature heat insulating pipe so as to form a superconductive cable. Because the spiral directions of waving of the inner and outer pipes are opposite to each other, even when the pipe is bent or the axes of the inner and outer pipes are deviated, the spiral parts are in a crossed state, and hence the range of narrowing the gap can be restrained to be small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic heat insulating tube used for, for example, a superconducting cable and a superconducting cable using the same.

[0002]

2. Description of the Related Art FIG. 2 is a side view showing a partial cross section of an essential part of an example of a conventional cryogenic heat insulating tube. In the drawing,
Reference numeral 1 denotes an inner tube made of aluminum or the like with a spiral wave having a flow path 3 for a cryogenic refrigerant such as liquid nitrogen formed therein, and a multi-layer heat insulating material in which a metal foil having a small radiation coefficient and a plastic film are laminated on the outer circumference thereof. 4 is provided. Further, on the outside thereof, there is provided an outer tube 2 made of aluminum or the like having a spiral wave provided with a spiral in the same direction as the inner tube 1, and a vacuum is drawn between the outer tube 2 and the inner tube 1. ing.

[0003]

In the above-described conventional cryogenic heat insulating pipe, since the inner pipe and the outer pipe have the same corrugated spiral direction, the heat insulating pipe may be bent or the core of the inner and outer pipe may be straight. When the displacement occurs, a portion where the gap g of the inner and outer tubes becomes narrower occurs, and that portion is generated spirally along the corrugated pitch, so that the range becomes longer. Therefore, when the gap g becomes extremely narrow, the multilayer heat insulating material is pressed against the inner and outer tubes along the spiral pitch. As a result, there are problems that the degree of adhesion between the multilayer heat insulating material and the inner and outer pipes increases, the amount of heat penetrating from the outer pipe due to heat conduction increases, and the multilayer heat insulating material is damaged and the heat insulating performance significantly decreases.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and provides a cryogenic heat insulating tube in which the narrowing range of the gap caused by the bending of the heat insulating tube or the misalignment of the cores of the inner and outer tubes is suppressed. The present invention provides a superconducting cable using the same, the first feature of which is a cryogenic heat-insulating tube in which the spiral directions of corrugations of the inner tube and the outer tube are reversed, and the second aspect of the present invention is also provided. The feature is in the superconducting cable in which the superconducting cable core is housed in the inner tube of the cryogenic heat insulating tube.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side view showing a partial cross section of an essential part of a specific example of a superconducting cable in which a superconducting cable core is housed in a cryogenic heat insulating tube of the present invention.
In the drawing, the same reference numerals as those in FIG. 2 represent the same parts. As shown in the drawings, in the cryogenic adiabatic pipe of the present invention, the inner pipe 1 with a spiral wave forming the refrigerant flow path 3 is formed.
And the outer tube 2 with the spiral wave provided on the outside
The corrugated spiral direction is formed in the opposite direction, and a vacuum is drawn between the inner tube 1 and the outer tube 2 to form a cryogenic adiabatic tube. A superconducting cable core 5 is housed in the inner tube 1 of the cryogenic heat insulating tube to form a superconducting cable.

In the cryogenic adiabatic tube of the present invention having the above-mentioned structure, since the spiral directions with corrugations of the inner and outer tubes are in opposite directions, the spiral portions intersect even if they are bent or the cores of the inner and outer tubes are displaced. As a result, the range in which the gap becomes narrow can be suppressed to be small. In this way, the gap becomes narrow only at the intersection of spirals,
It is possible to prevent an increase in the amount of heat penetrating due to heat conduction, reduce the range in which the multilayer heat insulating material is damaged, and suppress deterioration of the heat insulating performance of the heat insulating pipe. Therefore, the superconducting cable using such a heat insulating tube can maintain good performance with less deterioration in heat insulating performance even when the cable is bent.

[0007]

As described above, according to the cryogenic adiabatic tube of the present invention, even if bending or misalignment of the inner and outer tubes occurs, it is possible to suppress the deterioration of the adiabatic performance to a small extent. A superconducting cable using a tube can maintain stable heat insulation performance.

[Brief description of the drawings]

FIG. 1 is a side view showing a partial cross section of a main part of a specific example of a superconducting cable in which a superconducting cable core is housed in a cryogenic heat insulating tube of the present invention.

FIG. 2 is a side view showing a partial cross section of a main part of an example of a conventional cryogenic heat insulating tube.

[Explanation of symbols]

 1 Inner tube 2 Outer tube 3 Refrigerant flow path 4 Multi-layer insulation 5 Superconducting cable core

Claims (2)

[Claims] 1. A vacuum wave is drawn between an inner tube having a spiral wave and an outer tube having a spiral wave inside which a flow path for a cryogenic refrigerant such as liquid nitrogen is formed. The cryogenic adiabatic tube, wherein the corrugated spiral directions of the inner tube and the outer tube are opposite to each other. 2. A superconducting cable, characterized in that a superconducting cable core is housed in the inner pipe of the cryogenic heat insulating pipe according to claim 1.