JPH02232903A - Superconducting coil device - Google Patents

Abstract

PURPOSE:To facilitate the manufacture of the title superconducting coil device by a method wherein a spiral electromagnetic supporting member, having an aperture part on the outer circumferential side of a coil, is formed by chipping it out from a cylinder-shaped structural material, and after the outside surface of the conduit of a conductive type superconducting material has been insulation-treated, a superconducting coil is wound in such a manner that it is buried in the aperture part. CONSTITUTION:Spiral electromagnetic force supporting members 17 and 17 are chipped out from cylindrical high strength steel, a conduit type superconducting conductor 7 is fitted to an aperture part 18 and wound thereon. A turn-to-turn insulation-treated part 19 is provided on the conductor 7, and the increase of an eddy current loss generated by the contact between supporting members 17 and 17 is prevented by interposing an insulating sheet 20 between them. Also, a multilayer structure is formed by providing an interlayer insulating material 21, parts 22a and 22b that connect conductors between layers, a connection part between conduit type superconducting material for high magnetic field and one for low magnetic field, a spacer 23, a spool 24, an electromagnetic force supporting member and a ground insulation 26. According to this constitution, electromagnetic force is supported by the spiral supporting member the grading of coil is facilitated, and a reliable current transformer can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a superconducting coil device that employs a forced cooling method. [Prior Art] Figs. 4 to 6 show a conventional superconducting coil device of this type, which is disclosed in Japanese Patent Publication No. 59-12003, and in Figs. 4 and 5, (1) is a superconductor, (2
) is the electromagnetic force supporting structural member, (3) is the slot for storing the conductor, (4) is the insulating material, and (5) is the winding frame. Figure 6 schematically shows the electrical connection between conductors, (6a)
is the feeder wire, (6b) is the coil outer diameter side crossover wire, (6C
) is the crossover wire on the inner diameter side of the coil. Figure 7 shows, for example, the proceedings of the 35th Society of Cryogenics Research Conference (1986),
This is a so-called conduit type superconductor (F) that is cooled by forced circulation of supercritical pressure helium shown on page 120, (8) is a superconducting strand, (9)
) is a stranded conductor made by twisting a large number of superconducting wires into a bundle, (1
0) is a conduit made of high-strength stainless steel, for example, and keeps the inside of the conduit airtight from the outside. The gap <<11>> between the superconducting wires (8) is a cooling channel through which a coolant such as supercritical helium is pumped. In the above configuration, the superconducting coil winding method shown in FIG. Insert it into the slot and roll it in, and connect the crossover wire (6b), (
6c) Connect the wires so that the necessary current flows as a superconducting coil. This method consists of a superconductor (1) and an electromagnetic support structure member (
2) is wound at the same time, so it can be applied to methods that require large electromagnetic force, such as superconducting coil manufacturing methods for nuclear fusion reactors. The winding method shown in Figures 4 and 6 is a so-called pancake winding method. In the coil shown in Figure 4, one unit of coil is made up of four windings, but double pancake winding is usually used where one unit is made up of two windings. In the case of a superconducting coil that requires length in the axial direction, the required coil length is obtained by stacking many pancake coils in the axial direction. The conduit-type superconductor structure shown in Fig. 7 has a stranded conductor (9) made of a bundle of multiple superconducting wires (8) enclosed inside a conduit (10) made of high-strength steel such as stainless steel. The superconducting strands (8) are cooled by forced circulation of a coolant such as supercritical helium through the cooling channels (11) in the gaps between them. The characteristics of this method are that the conduit material acts as a strong member against electromagnetic force, so the strength of the conductor itself can be high, and since no refrigerant is required outside the conduit, reliable insulation can be achieved without compromising cooling properties. It has good voltage resistance, and the cooling area of the superconducting wire (8) is large, resulting in good superconducting stability.

For this reason, it is being researched and developed for use in large coils for nuclear fusion reactors, which have large electromagnetic forces and require insulation on the order of several +kV. [Problems to be Solved by the Invention] In the conventional superconducting coil device as described above, in the conduit-type superconductor shown in Fig. 7, the conduit material is high-strength steel, so the superconductor itself generates a considerable electromagnetic force. It is possible to support However, due to manufacturability issues, it is difficult to make the conduit sufficiently thick.
Large superconducting coils for fusion reactors with large electromagnetic forces require other structural members within the coil that can share the support of the electromagnetic force. The structure shown in Figure 4 can be considered as a candidate. A combination of these two methods has the characteristic that a coil with sufficient strength can be manufactured. Figure 8 shows only the necessary parts of the superconducting coil group of a tokamak-type fusion reactor.
13), balanced magnetic field coils (14a) to (14F>) for maintaining the plasma in the required shape, and a current transformer coil (15) that heats the plasma using the principle of a current transformer.Balanced magnetic field coil There are various ways to arrange the coils. Among these coils, the size of the current transformer coil has a great influence on the contents of the plasma experiment and the overall dimensions of the reactor, and the diameter of the magnetic field generation space (16) should be kept as small as possible. The magnetic field generated must be as high as possible, i.e. the current transformer coil (
The distance between the outer circumferential side of the coil 15) and the toroidal coil (13) must be as small as possible, and the thickness of the current transformer coil (15) must be as thin as possible. In addition, the current transformer coil (15) is a long coil in the axial direction, so when a current is passed and a magnetic field is generated, the maximum magnetic field is generated on the inner diameter side of the coil, and the radius. The magnetic field decreases as the value increases, and the magnetic field outside the coil is a fraction of the maximum magnetic field. In order to increase the magnetic field generated by the current transformer coil (15), it is necessary to use a compound-based material such as Nb Sn as the superconducting wire material. However, compound-based superconducting materials for high magnetic fields, such as NbSn, are more brittle than alloy-based superconducting materials for relatively low magnetic fields, such as NbTi.
Reliability is lower than alloy-based materials such as bTi. It is also expensive due to the technical difficulty of handling it. Therefore, in general, in a high magnetic field generating coil, Nb Sn is used only in the high magnetic field part.
A type of compound superconducting material is used, and NbT is used in the low magnetic field part.
An i-based alloy superconducting material is used to connect the two within the coil. This method is called grading. The current that can flow through a superconducting wire is a function of the magnetic field, and a larger current can flow on the low magnetic field side. In other words, if the current value is constant on the high and low magnetic field sides, grading allows the use of a smaller superconductor on the low magnetic field side, making it possible to reduce the thickness of the coil. On the other hand, when this grading method is applied to a combination of a conduit-type superconductor and the method shown in Fig. 4, it is difficult to connect the conduit-type superconductor in a narrow space within the slot of the electromagnetic force support structure member (2). This method has the disadvantage of being technically extremely difficult. Therefore,
In the pancake-wound coil method, which is a combination of the above two methods, the conduit-type superconductor uses the same technically difficult conductor for high magnetic fields from the inside to the outside, such as Nb Sn-based compound superconducting material. ．． Therefore, although the above-mentioned pancake winding can ensure coil strength, it has the fatal disadvantage of lowering technical reliability and becoming expensive. Furthermore, although the current transformer coil operates in pulses, the electromagnetic force support structure member shown in Figure 4, which supports several turns of superconductors in parallel, experiences a fluctuating magnetic field over a wide area, so AC losses due to eddy currents are generated. The increase in cooling heat load also poses a major problem. This invention was made to solve the above-mentioned problems, and even a large coil using a conduit-type superconductor can be supported against electromagnetic force. The purpose is to obtain a coil winding system that allows for [Means for Solving the Problems] A superconducting coil device according to the present invention has a spiral electromagnetic force support member having an opening on the outer circumferential side of the coil cut out of a cylindrical structural material, and a conduit of a conduit-type superconductor. After insulating the outside surface, a superconducting coil is wound in a spiral while embedded in the opening. [Function] Since the superconducting coil device of the present invention has a spiral winding having the electromagnetic force supporting member as described above, it is possible to connect conduit-type superconducting conductors in the space at the end of the coil. The electromagnetic force is supported by the electromagnetic force support member, and the grading of the coil becomes easy, making it possible to manufacture inexpensive and reliable current transformer coils. [Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. Figure 1 shows one layer of a solenoid coil, (17) is a spiral electromagnetic force support member machined from cylindrical high-strength steel, and (F) is an electromagnetic force support member. This is a conduit-type superconductor that is fitted into the opening (18) of (17) and wound. The conduit-type superconductor (7) is provided with inter-turn insulation (19). (20) is an insulating sheet to prevent electromagnetic force supporting members from coming into contact and increasing eddy current loss. Figure 2 schematically shows several layers. The inner diameter side is a conduit-type superconductor using superconducting material for high magnetic fields, and the outer diameter side is a conduit-type superconductor using superconducting material for low magnetic fields. (21) is the insulation material between the eyebrows. (22a) and (22b) are the connections between the conductors between the eyebrows, and (22c) is the connection between the conduit-type superconductor for high magnetic fields and the conduit-type superconductor for low magnetic fields. (23) is a spacer, (24) is a winding frame, (
25) is the outermost electromagnetic force supporting member, and since it is the outermost member, it can be a band-shaped member. (26) is the ground insulation. Since the electromagnetic force is weak in the outermost layer, the outermost electromagnetic force support member (
In some cases, it is possible to provide direct earth insulation (26) without 25). Next, we will explain the operation. When a current flows through a conductor in a magnetic field, an electromagnetic force of magnetic field x current acts on the conductor in a direction perpendicular to the direction of the magnetic field and the direction of the current. In other words, for a circular coil, this is the coil expansion force. The electromagnetic force, which is this expansion force, is supported by the electromagnetic force support member of the next layer on the outer circumferential side of the conductor on which the electromagnetic force acts. In this way, the electromagnetic force generated in each superconductor is supported by the electromagnetic force support member in the next layer, and the electromagnetic force is supported by the coil as a whole without any problems. On the other hand, since the inter-conductor connection can be provided at the axial end of the coil where there is a relatively large amount of space, the space utilization efficiency does not deteriorate as in the case of pancake-shaped coils. In this example, after the inter-turn insulation (19) is applied to the conduit type superconductor (7), the wire is wound in a spiral shape while being embedded in the opening (18) of the spiral electromagnetic force support member (17). As shown in Fig. 3a, a conduit-type superconductor (F) is embedded in the opening (18) of a spiral electromagnetic force support member (17) without inter-turn insulation, and its outer periphery is Turn-to-turn insulation (
19) can also be applied. In addition, since axial electromagnetic force also acts on the current transformer coil, as shown in Figure 3b,
A high-strength stainless steel strip (27) is attached to the opening (18) of the spiral electromagnetic force support member (17) into which the conduit-type superconductor (7) is inserted, which is further outward from the conduit-type superconductor. If inserted, it is possible to further increase the strength against electromagnetic force in the axial direction.Furthermore, in this example, the advantages were mainly described from the perspective of connection between conductors in terms of space utilization of the current transformer coil. This electromagnetic force supporting member has the advantage that it can be easily manufactured from a cylinder by machining using only a lathe. [Effects of the Invention] As described above, according to the present invention, the outer diameter of the coil can be adjusted from a cylindrical structural material. After cutting out a spiral electromagnetic force support member with an opening on the side and applying insulation to the outer surface of the conduit of the conduit-type superconductor, the wire is wound in a spiral shape while being buried in the opening, and the conductor connection part is connected to the coil axis. Since it is provided at the end of the direction, the electromagnetic force is supported by the spiral electromagnetic force support member, and the grading of the coil is also facilitated, making it possible to manufacture inexpensive and reliable current transformer coils. Another advantage is that the force support member can be easily machined from a cylinder using only a lathe.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 show one embodiment of the present invention.
Figure (a) is a partially cross-sectional schematic perspective view, and figure (b) is the same figure (&
), Figure 2 is a partial cross-sectional view of several layers, and Figure 3 is a partial cross-sectional view of several layers.
Figure a and Figure 3b are partial cross-sectional views of other embodiments, respectively.
Figures 4, 5, and 6 show conventional superconducting coil devices, where Figure 4 is a partially sectional perspective view, Figure 5 is a partial perspective view of the one in Figure 4, and Figure 6 is a wiring diagram. It is. FIG. 7 is a cross-sectional view of a conventional superconducting conductor, and FIG. 8 is a schematic cross-sectional view of an example of the use of a conventional superconducting coil device. (7)... Conduit type superconductor, (17)...
Spiral electromagnetic force support member, (18)...opening, (19)...interturn insulation, (20)...insulation sheet, (2l)...interlayer insulation material, (27)... ...High strength stainless steel strip. In each figure, the same reference numerals indicate the same or equivalent parts. Island 1 diagram (Q) (b) Agent Masuo Oiwa 7: Koichi, G type 8tjI! ．． Q17: Suha 0i 51 collection, electric power 4 shuttle parts 1all'
LO Seisaku 4, Figure 5, Figure 30, Figure 3b

Claims (1)

[Claims] In a superconducting coil device in which superconducting wires are twisted into a bundle, the surroundings are covered with a conduit made of high-strength stainless steel, and a conduit-type superconductor is wound into a cylindrical shape for cooling by forced circulation of a refrigerant inside the conduit. , the continuous winding direction is the axial direction, and the conduit type superconductor is inserted into the opening of a spiral electromagnetic force support member made of high strength stainless steel and having an opening on the outer diameter side of the coil. Characteristic superconducting coil device.