DE7602013U1 - Superconductor - Google Patents

Description

166/75 We.

BBC Aktiengesellschaft Brown, Boveri & Cie., Baden (Switzerland)

Superconductors and processes for their manufacture

The invention relates to a superconductor with a plurality of superconductor wires forming a cable, in which a large number of filaments made of superconducting material are embedded in a matrix made of electrically normal conductive material and a method for manufacturing this superconductor.

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For example, to generate the magnetic fields required for nuclear fusion with field strengths of up to 12 Tesla, superconductors are required for electrical currents of up to 50 * 000 A and more. The superconducting materials suitable for such high electrical currents and consisting of an intermetallic A15 compound, such as Nb ₃ Sn, V ₃ Ga or V ₃ Si, however, have the disadvantages that they are very brittle and only slightly after the reaction annealing has been carried out may be bent and stretched if their superconducting properties are not to be impaired.

In addition, with such high currents, the Forces acting on superconductors are significantly higher than previously usual, so that high demands are placed on the mechanical strength of the superconductor.

The object of the invention is to create a superconductor, in its manufacture, further processing and Use the risk of damaging the filaments made of superconducting material Minimum is reduced.

The inventive superconductor of those mentioned at the beginning Type is characterized in that the cable

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with one that runs in its longitudinal direction and consists of at least two functionally different parts Support structure is connected by the wires forming the cable with each other and with the adjacent parts of the supporting structure are plastically connected, and that the strength of the in use of the superconductor, connections between the various parts of the supporting structure that are relevant in terms of strength at least approximately corresponds to that of the supporting structure at the operating temperature of the superconductor or higher. The support structure can, for example, act on the cable Forces-absorbing support part and a stabilizing part or a support part and a cooling part or a Have support part, a stabilizing part and a cooling part.

If such a superconductor is bent during the manufacture of a coil, for example, then they can Cable-forming wires give way to each other and to the adjacent parts of the support structure, although the superconductor as a whole has an extraordinary resistance to external influences acting on it Has forces, so that a loading

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Damage to the filaments made of superconducting material when winding the coil to a minimum is reduced. This is very important, since damage to the superconductor is only just beginning the fully assembled magnet when it is first put into operation a considerable economically Represents loss

It is useful if the wires forming the cable with each other and with the adjacent parts the supporting structure is soft-soldered and at least the strength when using the superconductor relevant connections of the support structure are formed by brazing or welding.

In order to avoid the risk of damage to the filaments made of superconducting material in the event of a To keep the bending of the superconductor as small as possible, it is advantageous if the superconductor wires containing cables is concentrated around the neutral layer when the superconductor is bent.

To cool the superconductor to its operating temperature to be able to, it is useful if the carrying

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structure is provided with at least one cooling channel or cooling tube running along the cable.

For the electrical stabilization of the superconductor, it is also advantageous if the support structure with at least one of electrically normal conductive material running along the cable, for example Copper or aluminum, existing stabilization part is provided.

To increase the mechanical strength of the superconductor, it is useful if the support structure with at least one that runs along the cable and has a higher strength than the stabilizing material Reinforcement part is provided.

To further protect the filaments made of superconducting material against damage during the Production and further processing of the superconductor, it is advantageous if the one containing the superconductor wires Cable at least one stabilization and / or one running parallel to the superconductor long axis Includes reinforcement wire.

In order to minimize eddy current when the superconductor is used in rapidly changing magnetic fields.

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To preserve losses, it is useful if the stabilizing material is divided into several wires and this from a CuNi alloy, for example existing high-resistance layer are separated.

In order to pass through very high electrical currents, it is advantageous if the superconducting material consists of an A15 intermetallic compound, for example Nb ₃ Sn ₁ V ₃ Ga or V ₃ Si.

The invention also relates to a method for producing the superconductor according to the invention, which is characterized in that the cable is arranged inside the support structure, the individual Connects parts of the supporting structure to one another and then soft-soldering the cable.

The invention is explained below with reference to the drawing, for example. Show it;

Fig.l shows a section through a first exemplary embodiment of an inventive

Superconductor;
2 shows a section through a second exemplary embodiment of a superconductor according to the invention;

Pig. 3 shows a section through a third exemplary embodiment of one according to the invention

Superconductor;
4 shows a section through a fourth exemplary embodiment of one according to the invention

Superconductor;
5 shows a section through a fifth exemplary embodiment of one according to the invention

Superconductor; and
6 shows a section through a further exemplary embodiment of a superconductor according to the invention.

In the embodiment shown in Figure 1, the superconductor is provided with a plurality of superconductor wires 2 forming a cable 1, with the latter having a large number of filaments consisting of an intermetallic A15 compound in a matrix consisting of material that is normally electrically conductive at the operating temperature of the superconductor made of an alloy such as Cu-Sn for Nb ₃ Sn filaments or Cu-Ga for V ₃ Ga filaments, etc. are embedded. This matrix can also have highly conductive material such as copper or aluminum for stabilization.

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In addition to the superconductor wires 2 contains the Cable 1 still made of stabilizing material Wires 3 and reinforcing wires 4 made of steel, with the aim of achieving the lowest possible extensibility of the cable 1, the reinforcement wires 4 run parallel to the longitudinal axis of the cable.

For electrical stabilization of the superconductor, cables 1 running along the cable are electrically good conductive material such as copper or aluminum, existing stabilizing and supporting parts 5 and 6, the one stabilizing and supporting part 6 additionally having a cooling channel 7 is provided for the passage of a cooling medium.

The superconductor is also for additional increase its mechanical strength completely encased on its outside by a steel jacket 8, wherein the latter is welded along the seam 9.

The stabilizing and supporting parts 5 and 6 and the steel jacket 8 are mutually via hard solder, for Example of a Cu-Ag hard solder, firmly connected to one another and thus form a high-strength component which, in terms of strength, is used for the production of the Implementation of the nuclear fusion required magnetic coils is quite suitable.

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In the production of the superconductor shown in Figure 1 there is? the lots transposed one below the other Flexible cables 1 containing wires 2, 3 and 4 inside the supporting structure consisting of parts 5,6 and β arranged, the individual parts 5,6 and 8 of the latter firmly connected to one another by hard soldering, the steel jacket 8 between the openings in part 5 10 welded along the seam 9 and then the wires 2, 3 and 4 forming the cable 1 with one another and with the adjacent parts 5 and 6 of the support structure by introducing soft solder through provided along the superconductor Openings 10 soft-soldered

The support structure parts 5, 6 and 8, which are brazed or welded to one another, form a mechanically high-strength superconductor, which has the advantage that when it is bent, for example when winding a magnet coil, the flexible arrangement and design of the cable 1 means that the soft-soldered superconductor wires are slightly displaced 2 among each other and with respect to the stabilizing and supporting parts 5 and 6, so that the risk of damage to the filaments made of superconducting material is very much reduced. The soldering time and the melting point of the brazing solder used, which is around 700 ° C., are in such a range that the superconducting properties of the filaments made, _{for example, of Nb 3 Sn}

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- 10 - is not affected "

In order to reduce the tensile stresses acting on the superconductor wires 2 when the superconductor bends To keep it as small as possible, the cable 1 is arranged in such a way that it is concentrated around the layer that is neutral when the superconductor is attached.

In the embodiment shown in FIG. 2, in contrast to the embodiment shown in FIG. 1, two cooling pipes 13 and 14 running symmetrically to the cable 1 are inserted into the correspondingly shaped support and stabilizing parts 5 and 6 inserted.

In this embodiment, the superconducting wires 2 forming the cable 1 are with each other and with the adjacent parts 5 and 6 of the support structure and the two parts 5 and 6 soft-soldered to one another. To achieve the mechanically high-strength support structure is the steel jacket 8 completely enveloping the outside of the superconductor with the outside of the support and stabilization parts 5 and 6 brazed or welded.

The embodiment shown in FIG. 3 differs from the embodiment shown in FIG

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all in that the cooling ducts intended for the cooling medium run through two seamlessly drawn steel tubes 13 and 14 existing reinforcement parts are formed.

In order to minimize eddy current losses when using the superconductor in rapidly changing magnetic fields to be obtained are those which are normally electrically conductive at the operating temperature of the superconductor Stabilization material such as copper or aluminum, existing support and stabilization parts 5 and 6 into several parallel wires 5a, 5b, 5c and 5d as well as 6a, 6b, 6c and 6d divided, and these wires 5a to 5d and 6a to 6d individually by one, for example made of a CuNi alloy existing high-resistance layer separated.

In addition, the individual superconductor wires 2 can each be surrounded by a high-resistance layer.

To achieve a certain flexibility of the cable 1 when bending the superconductor, i.e. to reduce the risk of damage to the _{filaments made of brittle superconducting materials such as Nb 3} Sn, V Ga or V ₃ Si, the superconductor wires 2 are here as well with the adjacent parts 5,6,13 and 14 soft-soldered. To achieve a

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The supporting and stabilizing parts 5 and 6, the steel pipes 13 and 14 and the steel jacket 8 are brazed or fused together with one another, as strong as possible.

In the illustrated embodiment in Figure 4 which is

' consisting of a large number of superconductor wires 2

'■ Cable 1 in a recess of a copper made

with two cooling channels 11 and 12 provided support, stabilization and cooling part 6 is arranged. For reinforcement the supporting structure is a strong steel profile 15 by means of brazing on the outside of the Supporting, stabilizing and cooling part 6 attached, so that a component that is very strong in terms of strength is formed.

To avoid damage to the superconductor filaments in the To avoid production and further processing, the superconductor wires 2 are among themselves and with the adjacent ones Parts 6 and 15 of the mechanically stable support structure to achieve a low flexibility of the superconductor wires soldered with a soft solder, and the cable 1 is as viewed over the cross section of the superconductor arranged so that it is concentrated around the layer which is neutral when the superconductor is bent.

It is of course also possible to use the geometric arrangement and to choose the materials so that the cable 1 on the finished bent superconductor is in its on pressure claimed area.

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In the embodiment shown in Figure 5, the support structure is through a for the passage of a Coolant formed seamlessly drawn cooling tube 16, which is made of electrically good conductive stabilization material such as copper or aluminum. The cooling pipe 16 is to increase its mechanical Strength reinforced on its inside with a reinforcing tube 17 made of steel. The two Pipes 16 and 17 are to achieve the highest possible mechanical strength of the support structure with each other soldered.

The cable 1 consisting of the superconductor wires 2 is on the outside of the stabilizing material existing tube 16 arranged, the superconductor wires 2 under and with the adjacent Tube 16 to achieve a low flexibility of the superconductor wires 2 plastic, for example are connected by means of a soft solder.

In the embodiment of a superconductor shown in Figure 6, the cable 1 of two identical, for electrical stabilization and to support the latter, made of copper or aluminum existing molded parts 19 enclosed. To increase

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The mechanical strength of the two molded parts 19, for example, reinforcing wires 18 consisting of a CuAl bronze are embedded in these molded parts 19 and metallurgically connected to them. the Superconductor wires 2 of the cable 1 are plastic with one another and with the adjoining molded parts 19 e.g. connected via soft solder. The soft solder can after the hard soldering of the two molded parts 19 through several openings 20 provided in the latter are introduced into the interior of the superconductor. The reinforcement wires can be embedded, for example, by inserting bronze rods in grooves and then Rolling or drawing or by extruding together with the molded parts 19 take place, with diffusion annealing for the metallurgical connection of the reinforcement material with the stabilization material can be carried out.

Claims (20)

* 4 - 15 - 166/75 ■ i -.- claims 1. Superconductor, with a multiplicity of superconductor wires forming a cable, in which a large number of filaments of superconducting material are embedded in a matrix consisting of electrically normal conducting material, characterized in that the cable (1) has a longitudinal direction, support structure consisting of at least two functionally different parts (5, 6, 8, 13, V \, 15, 16, 17, 18, 19) is connected by the wires (2, 3, Ό forming the cable (1) with each other and are plastically connected to the adjoining parts (5, 6, 13, 14, 15, 16) of the support structure, and that the strength of the connections between the various parts of the support structure that is relevant in terms of strength when the superconductor is used is at least approximately that of the support structure at the operating temperature of the superconductor equals or is higher. 166/75 - 16 - 2. Superconductor according to claim 1, characterized in that the wires (2,3,4) forming the cable (1) are soft-soldered to one another and to the adjacent parts (5,6,13-16,19) of the supporting structure . 3. Superconductor according to one of Claims 1 and 2, characterized in that at least the connections of the supporting structure that are relevant in terms of strength when the superconductor is used are formed by hard soldering or welding. 4 «superconductors according to one or more of the preceding Claims, characterized in that the cable containing the superconductor wires (2) (1) is completely enclosed by the supporting structure (5,6,8,13,14,15,19). 5 »Superconductors according to one or more of the preceding Claims, characterized in that the cable containing the superconductor wires (2) (1) around which the neutral layer is concentrated when the superconductor is bent. 166/75 6. Superconductor according to one or more of the preceding claims, characterized in that the support structure with at least one along the cable (1) running cooling channel (11,12) or cooling pipe (6; 13,14; 16) is provided. 7. Superconductor according to one or more of the preceding claims, characterized in that the support structure with at least one of electrically normal conductive material, for example copper or, which runs along the cable (1) Aluminum, existing stabilizing part (5,6; 16,19) is provided. 8. Superconductor according to one or more of the preceding claims, characterized in that the support structure with at least one running along the cable (1), preferably one around at least 50% higher strength than the reinforcement part having the stabilizing material (8; 13,14; 15; 17) is provided. 9. Superconductor according to one or more of the preceding claims, characterized in that the matrix of the superconductor wires (2) consists of reinforcement and / or stabilization material. 7602013 09/15/77 166/75 - 18 - 10. Superconductor according to one or more of the preceding claims, characterized in that. » Reinforcement material embedded in the stabilization matrix and preferably metallurgically with it connected is. 11. Superconductor according to one or more of the preceding claims, characterized in that the cable (1) containing the superconductor wires (2) has at least one stabilization and / or contains a reinforcing wire (3 or 4) running parallel to the longitudinal axis of the superconductor. 12. Superconductor according to one or more of the preceding claims, characterized in that the wires (2, 3, 4) forming the cable (1) are wired, stranded, interwoven or are transposed. 13. Superconductor according to one or more of the preceding claims, characterized in that the cable (1), viewed over the cross-section of the superconductor, is arranged in such a way that that it is located on the fully bent superconductor in the area under pressure 7602013 08/15/77 166/75 A / 14. Superconductor according to one or more of the preceding claims, characterized in that the support structure is formed by a cooling tube (16) intended for the passage of a coolant is made of electrically good conductive stabilization material, such as copper or aluminum, and that the cable (1) is wound onto the outside of the cooling tube (16) is. 15. Superconductor according to claim 14, characterized in that the cooling tube (16) to increase its mechanical strength on its inside or outside with one preferably made of steel existing reinforcement tube (17) is reinforced 16. Superconductor according to one or more of the preceding claims, characterized in that the superconductor wires (2) from a high-resistance one consisting, for example, of a CuNi alloy Layer are surrounded and / or have high-resistance intermediate layers between the filaments. 17. Superconductor according to claim 7, characterized in that the stabilizing material in several 7602013 09/15/77 166/75 - 20 - Wires (5a, 60, 5c, 5d; 6a, 6b, 6c, 6d) split and this separated from a high-resistance layer consisting, for example, of a CuNi alloy are. 18. Superconductor according to one or more of the preceding claims, characterized in that the superconducting material consists of an intermetallic A15 compound, for example of Nb ₃ Sn, V ₃ Ga or V ₃ Si. 19. Superconductor according to one of claims θ to 11, characterized in that the reinforcing material made of alloy steel, a high-strength Alloy, a Cu-Al, Cu-Ga, Cu-Sn or Cu-Ni or one based on such metals based on another alloy » 20. Superconductor according to claim 8, characterized in that the cross section and type of reinforcement material is selected so that the superconducting filaments are used in the production, further processing and the operation of the superconductor, the stresses to be expected in its longitudinal direction are not affected stretched more than about 0.2%. BBC Aklionti ^ rüs · hoff Brown, B ην ei ft Uns. 7602013 09/15/77