JPS6245105A - Superconducting coil - Google Patents

Abstract

PURPOSE:To inhibit the quantity of heat intruding into a vessel to a low value by bonding a first pipe, which has a notch and is fitted to a current lead through an insulating film, and a second pipe, which is fitted to the first pipe and to which force in the radial internal direction works, in a shielding manner. CONSTITUTION:Previously divided stainless pipes 21a, 21b are welded, and the inner diameters of the stainless pipes are reduced, thus working force in the radical internal direction to aluminum pipes 20a, 20b. In this case, the inner surfaces of the aluminum pipes 20a, 20b are brought into contact with an insulating tube 12 by pressure, and the outer surfaces of the aluminum pipes 20a, 20b are brought into contact with the inner surfaces of the stainless pipes 21a, 21b by pressure. Accordingly, the efficiency of thermal conduction can be improved largely, thus remarkably lowering the quantity of heat intruding into a coil housing vessel.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to superconducting coils.

[Technical front of the invention and its problems]

In general, superconducting coils are capable of generating a strong magnetic field with a small amount of electric power, and are used, for example, in nuclear fusion devices, diagnostic imaging devices, single-unit lifting and mounting, and the like.

FIG. 3 is a 1g7i plane view showing the configuration of the main parts of this type of conventional superconducting coil. In FIG. 3, the coil 1 is immersed in liquid helium 2 stored in a helium container 3 serving as a coil storage container.

The helium container 3 is also covered with a heat shield 4, and the entire helium container 3 is held within a vacuum container 5.

A current lead 6 for passing current through the coil 1 passes through the upper wall of the helium container 3, the shield 4, and the upper wall of the vacuum container 5 and is led out.

Here, the temperature of the shield 4 is maintained at approximately 4.2 to 100K, which prevents heat from the chaste container at atmospheric temperature from directly entering the liquid helium 2, and also prevents the shield 4 from directly entering the liquid helium 2.
The configuration is such that the heat transmitted through the current leads 6 and penetrating into the liquid helium 2 is removed on the way through a thermal anchor 7 that connects the current leads 6 and - in a thermally conductive manner.

FIG. 4 is an enlarged sectional view of the superconducting coil taken along the line A-A, and the outer periphery of the copper vibe 11 is connected to the insulating tube 12.
These are the current leads 6 referred to herein.
It consists of This current lead 6 has an aluminum pipe 13a divided into two.

A stainless steel pipe 14 is fitted through the stainless steel pipe 13b, and the stainless steel vibrator 14 is held by a pair of linear anchors 7a and 7b connected by bolts 15.

Thus, while the copper vibrator 11 is kept insulated from others by the insulating duplex 12, the aluminum vibrator 13a, 13b,
Stainless steel vibe 14 and thermal anchors 7a, 7
It is thermally conductively coupled to the shield 4 via b.

Here, the aluminum vibes 13a and 13b are provided only in a part of the thermal anchor, and the copper vibe 13 can be considered as a path for the heat from the popular side to the liquid helium, and the heat is transferred to the thermal anchor 78. The structure is such that it is absorbed by the shield 4 via 7b.

By the way, in order to efficiently absorb this heat, the copper vibrator 11, the insulating tube 12, and the aluminum vibrator 13a, 1
3b, it is necessary to bring the stainless steel vibrators 14 into pressure contact with each other. Of these, the insulating wire L-112 is brought into close contact with the copper pipe 11 by heat shrinkage, so the contact between the two is considered to be good. However, between the insulating tube 12 and the aluminum vibes 13a, 13b, between the aluminum vibes 13a, 13b and the stainless steel pipe 14,
Since a small gap is required during assembly, a pressure contact state cannot be obtained, and the heat conduction efficiency is correspondingly low, and heat cannot be removed sufficiently.

Thus, in conventional superconducting coils, the amount of evaporation of liquid helium increases due to heat intrusion, which not only increases the number of times the shortage must be replenished, but also increases the consumption of expensive liquid helium, which increases operating costs. It had the disadvantage of rising prices.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks, and it is possible to significantly suppress the amount of heat intrusion into the coil storage container, thereby reducing the number of refills of liquid refrigerant such as liquid helium, and reducing operating costs. ffl that can significantly reduce
? The purpose is to provide a U-conductor coil.

[Summary of the invention]

To achieve this objective, the present invention provides a
A tubular current lead is held in a coil storage container covered with a shield, and a tubular current lead having an insulating film on the outer periphery is led out through the shield and the wall of the vacuum container, and is coupled to the shield in a thermally conductive manner. In the superconducting coil, the first superconducting coil has a notch in at least one location in the circumferential direction and fits into the current lead through the insulating film.
and a second pipe that fits into the first pipe and is welded at at least one point in the circumferential direction so that a radially inward force acts on the first pipe during cooling. The present invention is characterized in that this second pipe is coupled to the shield.

[Embodiments of the invention]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention, showing the portion gripped by a thermal anchor.

In the figure, the same reference numerals as in FIG. 3 indicate the same elements. Although the aluminum vibrators 20a and 20b provided on the outside of the insulating duplex 12 are divided into two on a plane including the axis, when pressed against the insulating tube 12, a gap δ is created between the divided surfaces. In addition, a notch 20c is formed at the radial end of the dividing surface, and the pre-divided stainless steel vibrator 218
．． The difference from FIG. 3 is that 21b is welded at a position corresponding to the notch 20C.

In this FIG. 1, a stainless steel vibrator 21a.

21b is an aluminum vibe 20a between the insulating tube 12
, 20b are inserted and welded with the divided portion aligned with the position of the notch 20c.

Generally, if a pipe is divided circumferentially and the divided parts are welded together, the diameter of the vibrator becomes much smaller. 21a.

By welding 21b and reducing its inner diameter, a radially inward force is applied to the aluminum vibes 21a and 21b. Since there is a gap δ between the divided portions of the aluminum vibes 21a and 21b, the inner surfaces of the aluminum vibes 20a and 20b are in pressure contact with the insulating duplex 12, and the aluminum vibes 20
The outer surfaces of the stainless steel vibrators 21a and 21b come into contact with the inner surfaces of the stainless steel vibrators 21a and 21b.

J3, notch 20 provided in the dividing part of the aluminum vibrator
C is a shield to make it difficult for heat to be transferred to other parts during welding.However, since the material used here itself has excellent thermal conductivity, the insulation tube 12μ is easily damaged by thermal shock. It is in. To prevent this, a cooling medium such as water may be passed through the copper vibe 11.

Thus, according to this embodiment, the aluminum vibes 20a and 20b are connected to the insulating tube 12.
, 20b, the stainless steel vibrators 21a and 21b can be brought into pressure contact with each other, so the heat transfer efficiency can be greatly improved compared to conventional devices, thereby significantly reducing the amount of heat intrusion into the coil storage container. can be done.

FIG. 2 is a perspective view showing the structure of another embodiment of the present invention. This is the helium container 3 and vacuum container 5 shown in FIG.
Corresponding to the fact that both are made of stainless steel plates, they firmly support the current lead 6 that passes through the walls, and also greatly increase the heat transfer efficiency.

At J3 in FIG. 2, the outer periphery of the copper vibe 11 is covered with an insulating duplex 12. On the outside of this insulating tube 12 are aluminum vibrators 20a and 20b as explained in FIG.
(not shown in FIG. 2) are provided, and furthermore, copper vibes 31a, 31 are provided on the outside of the aluminum vibes 20a, 20b.
b is placed. These copper pipes 31a and 31b are divided into two in advance, and by welding the divided portion 30c, a radially inward force is applied in the same way as described above. In this case, the outer side of the copper pipe 318.31b is gripped by the round anchors 7a, 7b (Fig. 1), but the stainless steel vibrator 21a is
, 21b are replaced by the copper vibes 31a, 31b, and the heat conduction efficiency is increased accordingly.

On the other hand, copper vibes 32a and copper vibes 33a are welded to the axial ends of the copper pipes 31a and 31b, and stainless steel vibes 32b and 33b of approximately the same size are welded to the ends of these body pipes. has been done.

Here, the copper vibe 32a and the stainless steel vibe 32b
, the copper vibe 33a and the stainless steel vibe 33b each constitute a dissimilar material joint, for example, the stainless steel vibe 32b
By welding the stainless steel vibrator 33b to the vacuum vessel 5 and the helium vessel 3 to the helium vessel 3, easy and firm joining is possible.

In the above embodiment, a two-part lζ aluminum pipe is fitted to the outside of the insulating tube 12, while a two-part stainless steel or copper vibe is placed outside the aluminum pipe and the divided parts are welded. Although we have explained the number of divisions, the number of divisions may be three or more, and
A notch may be provided at one location in the circumferential direction and this notch may be welded.

Further, in the above embodiment, an aluminum vibrator divided into two parts was provided outside the insulating tube 12, but a copper vibrator may be used in place of this, and the same effect as described above can be achieved.

〔Effect of the invention〕

As is clear from the above description, the present invention can significantly reduce the amount of heat intrusion into the coil storage container, thereby reducing the number of refills of liquid refrigerant such as liquid helium, which is difficult to handle. At the same time, the operating cost can be significantly reduced.

[Brief explanation of drawings]

Figure 1 is a sectional view showing the configuration of one embodiment of the present invention, Figure 2 is a perspective view showing the configuration of another embodiment, and Figure 3 is a sectional view of the configuration of a conventional superconducting coil. FIG. 4 is an enlarged cross-sectional view of the main parts of this superconducting coil. 1... Coil, 2... Liquid helium, 3... Helium container as a coil storage container, 4... Shield,
5... Vacuum container, 6... Current lead, 7.7a, 7
b... Thermal anchor, 11... Copper pipe, 12
...Insulating tube, 20a, 20b...Aluminum pipe as the first pipe, 21a...Stainless steel pipe as the second pipe,
31a, 31b...A torso vibe as a second pipe. Applicant's agent Sato - Yukumen? B (no change in $) Figure 1 Figure 3 Procedure 11 Official Book (Method) December 73, 1985

Claims (1)

[Claims] A coil storage container covered with a heat shield is held in a vacuum container, and a tubular current lead having an insulating film on the outer periphery passes through the shield and the wall of the vacuum container and is led out. In the superconducting coil to be coupled in a conductive manner, a first pipe having a notch in at least one location in the circumferential direction and fitting to the current lead through the insulating film; , a second pipe welded at at least one location in the circumferential direction so that a radially inward force acts on the first pipe during cooling;
A superconducting coil comprising: a second pipe, the second pipe being coupled to the shield.