JPS6026242B2 - superconducting cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting cable that is flexible, lightweight, and has excellent mechanical strength, having a corrugated core material provided in a hollow portion of a rectangular cross section.

Superconducting cable magnets used in superconducting synchrotrons, MHD generators, energy storage devices, nuclear fusion reactors, etc. use superconducting coils made of multiple layers of superconducting cables.

As a related matter, the following structures of superconducting cables are known. Figure 1 shows a flat composite superconducting material 1
This is a superconducting cable 4 in which a composite superconducting material 1 made of a stabilizing material and flat plates 2 having substantially the same shape are alternately stacked and joined together with solder 3 to be integrated.

This superconducting cable 4 uses a flat plate 2 made of copper as a stabilizing material to prevent burnout that occurs when transitioning from a superconducting state to a normal conducting state, so it has a heavy structure and creates a large superconducting coil with a large current capacity. I can't.

Further, since the structure is made by laminating the flat composite superconducting material 1 and the stabilizing material in the longitudinal direction, the compressive strength is highly variable and the flexibility is poor.

Furthermore, since the contact surface with the cryogenic refrigerant is limited to the outer peripheral surface of the superconducting cable 4, there is a drawback that the cooling efficiency by the cold butterfly is low. As an improved version of the superconducting cable 4, as shown in FIG. There is a superconducting cable 4 in which a plurality of twisted composite superconducting materials 1 are attached and cooling grooves 6 are formed between the flat plate 2 and the composite superconducting materials 1.

Since this superconducting cable 4 is provided with cooling holes 5 and cooling grooves 6, the contact area with the cryogenic cooling chamber is large, and the cooling efficiency is better than that of the above-mentioned flat superconducting cable 4.
Since the cooling holes 5 are formed in the stabilizing material 2, the strength is reduced, and if the current capacity is increased, the burnout prevention function by the stabilizing material 2 will not be sufficiently achieved.

Further, since the composite superconducting material 11 is not twisted, the shapes of both ends of the superconducting cable 4 along the longitudinal direction are disordered, which causes stress concentration and significantly deteriorates the superconducting properties. In addition to the above-mentioned superconducting cable 4, as shown in FIG. 3, there is a superconducting cable 4 called a forced cooling cable in which a plurality of composite superconducting materials 1 are concentrated and inserted into a tube 7 made of stainless steel. be.

This superconducting cable 4 has drawbacks such as poor maneuverability of the tube 7 and the need to increase the wall thickness of the tube 7 in order to increase its strength against compression in the vertical direction. In view of the above, as a result of various studies, the present invention forms a wave-shaped cross-sectional structure in the hollow part of a superconducting cable having a hollow part and a rectangular cross-section, thereby making it flexible, lightweight, and mechanically strong. He saw an excellent superconducting cable and put it out there.

That is, the present invention provides a superconducting cable having a rectangular cross section and having a hollow portion made of constituent members of a stabilizing material, a reinforcing material, and a composite superconducting material. This is a superconducting cable made by inserting flat plate-shaped composite superconducting materials in the form of corrugated bodies.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

FIG. 4 shows an embodiment of the present invention, and this superconducting cable 9 has a flat plate shape as shown in FIG.
A flat composite superconducting material 12 in which a plurality of superconducting materials 14 are embedded in a mesh or spiral shape along the longitudinal direction of the stabilizing material is used, and the composite superconducting material 12 is compressed in the longitudinal direction. A plurality of cooling holes 16
The composite superconducting material 12 may also be used as a corrugated body 13 for reinforcement by being inserted into the hollow part 10 of a frame 11 made of a reinforcing material having a rectangular cross section and having a hollow part bored therein.

Here, a frame 11 having a rectangular cross section and having the hollow portion 10 is used.
In addition to increasing the mechanical strength of the superconducting cable 9, the corrugated body 13 is housed in the frame 11, and the gap therebetween is used as a coolant passage 15.

The frame 11 may be made of any material that increases the mechanical strength of the superconducting cable 9, such as stainless steel or copper. Further, the wavy body 13 forms continuous undulations along the width direction inside the frame 11 having the hollow portion 10 to form a wavy shape, and the peaks and valleys are formed on the inner wall surface of the frame 11. It is attached by soldering to the.

The shape of this wave may be such that the amplitude A is greater than or equal to the pitch L, and the stabilizing material forming the wavy body 13 may be of any material having excellent electrical conductivity and thermal conductivity. , copper, steel-aluminum composite, etc. may be used. In addition, in the figure, a superconducting cable 9 is provided with a corrugated body 13 that is continuous along the longitudinal direction in the hollow part 10.
Although this has been described, a waveform 13 may be provided along the width direction separately from this. Further, the diameter of the superconducting material 14 may be selected from a diameter of about 5 to 50 cm depending on its use.

Here, the superconducting material 14 has a superconducting state at extremely low temperatures, and may be any material such as an alloy or compound of nioboo tin, nioboo zirconium, nioboo titanium, vanadium-gallium, or the like. The superconducting cable 9 having the above structure is used in a superconducting state by being immersed in cryogenic cold soot.
. . . Therefore, the cooling surface becomes the wall surface of the composite superconducting material 9 and the cooling butterfly channel 15, and cooling can be achieved with extremely high cooling efficiency.

Also, a reinforcing frame 1 that constitutes this superconducting cable 9
1, it is strong against stress from the main direction and the width direction.Furthermore, since the corrugated body 13 is provided inside it, it has excellent compression resistance in the thickness direction, and can resist differences in compressive strength. Since the orientation is 4.0 and the superconducting cable 9 has flexibility, buckling can be reduced. Next, specific examples according to the present invention will be described. As shown in Figure 5, a niobium core is twisted with a diameter of 30 feet and a pitch of 71 fences in a copper-tin alloy with a cross section of 2.5 sides x 35 lengths of 150 inches coated with copper of 0.5 thickness. A superconducting cable 9 as shown in FIG. 4 was obtained in the following manner using the flat composite superconducting material 12 in which 220,000 cables were buried. First, the composite superconducting material 12 is moved up and down 5 times along the longitudinal direction at intervals of 4 willows.
A wavy body 13 with a length of 50 skins formed by alternating superstructures of 3 ribs.
And so. As shown in FIG. 6, this wavy body 13 is held in a thickness of 0.2 cm from above and below.
A pair of reinforcing members (thickness: 0.5 mm) with 3-diameter cooling holes 16 made of reinforcing material made of oxygen-free copper bonded to stainless steel tape on the ribs, with 8 ribs spaced apart from each other. After attaching the kite, which has a width of 4 broadsides and a length of 50 kites, cooling holes 16 with a diameter of 3 ribs are placed at a distance of 8 ribs from the left and right sides in the reinforcing material made of oxygen-free steel bonded to stainless steel tape. After attaching a pair of reinforcing members (thickness: 2.5 ribs, width: 10.6 sides, length: 50 mm) to form the frame 11, slight compression molding is performed to form the cross-section 12 side. It was made into a rectangular shape with ×4 enemies. Next, add this to 10
-Heat to 690 oo in a high vacuum with Hg or more on the 5 side to 24
The composite superconducting material 12 was phosphorized for a period of time to form a nioboostin compound superconducting cable 9 which also served as a corrugated body 13 for reinforcement. On the other hand, as a comparison sample, as shown in FIG. 7, the outer circumferential surface of the composite copper/copper-tin-niobium composite superconducting material 12 (2.5 ribs x 35 ribs x 50 ribs) according to the present invention was plated with copper. stainless steel tape 20 (copper plate thickness 0.05
The ribs were coated with stainless steel ribs (2 ribs thick).

On the other hand, in the center along the longitudinal direction of one side of an oxygen-free copper plate with a thickness of 6 arms, a width of 4 arms, and a length of 5 legs, a depth of 1.45mm and a width of 37mm is placed.
．． A groove 22 with a length of 9 sides and a length of 50 mm is formed, and on the other side, grooves 21 (width: 4 mm, length in the longitudinal direction: 1 mm, A pair of grooved steel plates 21, 21 having a depth of 3) is prepared, and grooves 22, 2 formed in the longitudinal direction of the grooved steel plates 21, 21 are prepared.
After the organic copper plates 21 and 21 are assembled from above and below so that the composite superconducting material 12 is incorporated into the composite superconducting material 12, compression molding is performed to obtain a rectangular cross-sectional shape of 12 ribs x 4 broadsides as shown in FIG. did. Next, this is heated to 690°C in a high vacuum of 10-5 Hg or more.
qo and allowed to stand for 24 hours to form a niobium tin compound superconducting cable 4 through a solid state diffusion reaction. Through this treatment, the adjoining copper parts 24 were diffusion bonded.
As a result of a comparative test of the superconducting cable 9 according to the present invention and the superconducting cable 4 prepared as a comparison sample in terms of yield strength, compressive strength, energization state, and critical current value,
, we obtained the results shown in the table.

As shown in the table, the superconducting wire 9 according to the present invention and the superconducting wire 4 prepared as a comparative sample were found to have the same tensile strength from the mechanical tests '1} and '2} in the table, but the cable thickness It can be seen that the cable according to the present invention has better compressive strength. In addition, the maximum current capacity of both cables is almost equal according to the current carrying test shown in Table 2 (3), but when comparing the bending diameters at which the critical current deteriorates in the bending test shown in Table 2 (4),
It can be seen that the cable according to the present invention has improved flexibility compared to the comparison cable. As explained above, in the superconducting wire according to the present invention, the strength in the thickness direction of the cable is increased by having a corrugated structure inside. By using aluminum, it is possible to reduce the weight and manufacture large superconducting magnets with large current capacity, and since the flexibility is improved, it is possible to easily manufacture magnets of various shapes. can.

Furthermore, since the voids formed in the corrugated structure provide a large cooling area and reach a superconducting state with high cooling efficiency, it has remarkable effects such as being able to obtain a large current capacity without causing a training phenomenon.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a secondary superconducting cable made by alternately overlapping flat composite superconducting cables and stable beams, and Figure 2 is a conventional superconducting cable with cooling holes and cooling grooves. FIG. 3 is a perspective view showing a conventional superconducting cable in which a composite superconducting material concentrated in a tube is housed, and FIG. 4 is a partially cutaway perspective view of a superconducting cable according to the present invention. FIG. 5 is a perspective view showing the flat composite superconducting material used in the superconducting cable according to the present invention, and FIG.
FIG. 7 is a sectional view showing a superconducting cable according to the present invention in Example 2. FIG. 1... Composite superconducting material, 2... Flat plate, 3
...Solder, 4...Superconducting cable,
9... Superconducting cable, 10... Hollow part, 11... Frame, 12... Composite superconducting material 13... Wavy body, 14... ...Superconducting material. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. In a superconducting cable having a rectangular cross section and having a hollow portion made of constituent members of a stabilizing material, a reinforcing material, and a composite superconducting material, along the longitudinal direction or the width direction of the superconducting cable,
A superconducting cable characterized in that a flat plate-shaped composite superconducting material is inserted in the hollow portion as a corrugated body.