JPS6020591A - Cryogenic cooling medium transfer tube - Google Patents

Abstract

PURPOSE:To minimize the encroachment of heat from the outside by attaching electric paths and supporting members on an inside wall of an outer tube and arranging an inner tube in a manner it is located with a distance from the front end of said supporting members. CONSTITUTION:An inner tube 7 consisting of superconductive member is supported with floating apart from supporting members 10a, 10b and 10c and electric paths 11a, 11b and 11c are provided inside an outer tube 9. On this constitution, under a non-operation state at the beginning, the inner tube 7 is present on a part 10a of the supporting member and DC is flowed in the electric path 11a from a front surface of the present sheet of paper toward the back surface of it under this condition. Then, the magnetic field generated by the electric path 11a is going to be formed concentrically. However, the magnetic field formed by DC can not enter into the inner tube 7 because the tube 7 is superconductive, and the magnetic flux concentrates between the electric path 11a and the inner tube 7 to form a supporting recess generated by the magnetic field. By this recess of the magnetic field, the inner tube 7 can be supported in vacuum with floating apart from the supporting member 10a thereby enabling substantial reduction of the quantity of heat enchroachment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cryogenic refrigerant transfer pipe for conducting super-Et.

[Technical background of the invention and its problems]

In recent years, large-scale systems using many superconducting magnets such as nuclear fusion or accelerators have been realized, and the long-distance transfer of cryogenic refrigerants (liquid helium, etc.) used to cool these superconducting magnets and the transfer pipes used for this transfer are becoming more and more important. Reducing heat intrusion signals is becoming an important technical issue.

The background of the present invention and problems of the prior art will be explained with reference to FIGS. 1 and 2.

In FIG. 1, the cryogenic refrigerant 2 stored in the storage tank 1 is transferred through the transfer pipe 3 to the cryogenic container 5 which houses the superconducting magnet 4.

Generally, the system shown in FIG. 1 is used to centralize the production of cryogenic refrigerant and improve system efficiency in a system comprised of multiple superconducting magnets. 1st
In the figure, the cryogenic refrigerant manufacturing equipment is omitted in order to explain the IIFI 44, and only one set each of the storage tank and super conductive magnet is shown.

Now, the cross section of the aforementioned transfer pipe is generally constructed as shown in FIG. In FIG. 2, the cryogenic refrigerant flows through the inner tube 7 and is thermally isolated from the outside air (by the vacuum insulation layer 8), and from the outer tube 9 it flows through the support material 10 (for example, li', LP, etc.) with high thermal resistance. ) is supported.

In conventional cryogenic refrigerant transfer pipes with this structure,
There is a drawback that heat penetrates from the outer tube 9 to the inner tube 7 through the support material 10.

[Purpose of the invention]

An object of the present invention is to provide a cryogenic refrigerant transfer pipe that allows very little heat to enter from the outside.

[Summary of the invention]

In order to achieve this purpose, in the cryogenic refrigerant transfer tube of the present invention, the electric circuit 2 and the support material are attached to the inner wall surface of the outer tube, and the inner tube can be positioned with a gap between it and the tip of the support material. The inner tube is placed in such a way that a current is passed through the circuit, and the magnetic force causes the inner tube to float in the air.

[Implementation sequence of the invention]

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

The inner tube 7 is made of a superconductor, and supports 10a, 10b,
Support it in such a way that it can float from 10c. Support material 10a, 10
Make b and 10c shorter. An electric circuit is provided inside the outer tube 9. In FIG. 3, electric circuits 11a, llb, and llc are provided at the bases of the supporting members 10a, 10b, and 10c, but it is not necessarily necessary to have such a configuration.If multiple electric circuits are provided inside the outer tube 9, good. As the electric circuit, a normal bus bar or cable may be installed inside the outer tube.

Now, in such a configuration, in the initial de-energized state, the inner tube 7 rests on a part of the support member (10a in FIG. 3), and in this state, the electric circuit 11a is Direct current flows from the to the back. Then, the magnetic field created by the electric path 11a tries to form concentric circles, but because the inner tube 7 is a superconductor, the magnetic field created by the DC current cannot enter the inner tube 7 (Meissner effect). Magnetic flux is concentrated between the points 7 and 7, and a supporting concave surface is formed by the magnetic field. This magnetic field concave surface allows the inner tube 7 to be floated from the support member 10a and supported in a vacuum, making it possible to significantly reduce the amount of heat penetration.

In order to simplify the explanation, Fig. 3 shows an example in which current is passed only through the electric path 11a, but if current is passed in multiple locations as shown in Fig. 11b and IIC, and the support surface is covered by a magnetic field in multiple locations, then
It is possible to deal with bends in the transfer pipe.

Another method of floating the inner tube with almost the same structure is to use electromagnetic repulsion (Lorentz force). That is, in FIG. 3, the inner pipe 7 is made of a normal conductor (for example, a steel pipe). Then, a direct current flowing from the back to the front of the paper in Figure 3 is applied to the inner tube, and electric circuits 11a, llb, provided inside the outer tube 9,
When a direct current is applied to the llc from the front to the back of the paper in FIG. 3, the inner tube 7 is lifted away from the support member 10a+10b+10C due to electromagnetic repulsion (Lorentz force) and held in a vacuum. This 'electromagnetic repulsion force' is a phenomenon that occurs on a daily basis when current is passed through two wires facing each other, and when the current direction is the same, the wires attract each other, and when the current direction is opposite, they repel each other. This is a well-known principle.

Since the inner tube is at an extremely low temperature, its resistance value is at room temperature (300
The resistance value of K) is 171o00 or less. Therefore, the Joule heat generated by flowing one flow through the circular pipe is generated by the supporting material 10a.
This is less than the amount of heat that enters through heat conduction. Therefore, even when the inner tube is made of a normal conductor, the effect of reducing the amount of heat penetration by supporting the inner tube in a vacuum is extremely large.

Note that the support member 102 and the like may be attached to the inner wall surface of the outer tube 9 adjacent to the electric circuit 11a etc., instead of being attached on the electric circuit 118 etc. as shown in FIG. In addition, there is practically no problem with alternating current flowing through the electric circuit 11a etc. and the inner tube 7. [Effects of the Invention] As described above, in the cryogenic refrigerant transfer tube of the present invention,
Since the inner tube can be suspended in the air, the amount of heat intrusion can be extremely reduced.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view generally showing the situation in which a cryogenic refrigerant transfer pipe is used, Fig. 2 is a cross-sectional view of a conventional cryogenic refrigerant transfer pipe, and Fig. 3 is a cross-sectional view showing an embodiment of the present invention. It is a diagram. 1... Storage tank, 2... Cryogenic refrigerant, 3... Transfer pipe, 4... Superconducting magnet, 5 Cryogenic container, 7 Inner tube 8... Vacuum insulation no, 9... Outer tube, 10, 10a
, 10b, 10C-support material, 11a, llb,
llc - electrical circuit.

Claims (1)

[Scope of Claims] 1. An outer tube, an electric circuit disposed on the inner wall surface of the outer tube, and a supporting member fixed to the electric circuit or the inner wall surface of the outer tube and protruding in the central axis direction of the outer tube. A cryogenic refrigerant transfer tube comprising: an inner tube that is provided with a gap between it and the tip of the support material so as to be able to be held in the center of the outer tube. 2. The cryogenic refrigerant transfer tube according to claim 1, wherein the inner tube is made of a superconductor and a current is passed through the electric circuit. 3. The cryogenic refrigerant transfer tube according to claim 1, characterized in that the inner tube is a normal conductor, and the inner tube and the electrical circuit are used as reciprocating paths to carry current.