JPH08181014A - Superconductive magnet device and its manufacture - Google Patents

Abstract

PURPOSE: To provide a superconductive magnet device which stably maintains a high performance and can be easily manufactured by forming a magnet coil and a PCS coil using a compound superconductive wire and to provide its manufacturing method. CONSTITUTION: A superconductive magnet device is constituted by forming a magnet coil housing part 14 at the same coil frame 10, a PCS coil housing part 16, and a lead wire joint part housing part 15 and by housing a magnet coil 2 consisting of each compound superconductive wire at the housing parts, a PCS coil consisting of the compound superconductive wire and a heater wire, and a lead wire joint part 19 of both coils.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnet device used in a permanent current mode, and more particularly to Nb ₃ Sn.
The present invention relates to a superconducting magnet device including a magnet coil made of a compound superconducting wire such as V ₃ Ga and V ₃ Ga and a PCS coil, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A superconducting magnet device using a metallic superconducting wire such as NbTi or Nb ₃ Sn shows stable superconducting characteristics under a high current density of several hundreds to several thousand amperes / mm ² . It has been widely put to practical use as a medical device such as MRI (magnetic resonance imaging device) and a magnet device for generating a static magnetic field, and is expected to be applied to various applied devices such as a magnetic levitation train. When the superconducting magnet device is operated in a so-called permanent current mode in which a constant magnetic field is maintained for a long time even after the current supply from the external power supply is cut off, a persistent current switch (Persistent Cur
rent Switch. In this specification, it is abbreviated as PCS. ) Is used together.

FIG. 2 exemplifies a circuit configuration of a superconducting magnet device operated in a persistent current mode. PCS1
Is composed of a PCS coil 1a and a heater wire 1b wound between layers of the coil 1a. The PCS coil 1a is connected in parallel with a magnet coil 2 and is connected to an excitation power supply circuit 4 via a switch 3. The PCS 1 and the magnet coil 2 are housed in a cryostat 5 and used by being immersed in liquid helium. The PCS coil 1a
Has a non-inductive winding in order to avoid generation of its own magnetic field due to energization. Further, the PCS 1 is manufactured by being wound around a winding frame different from the magnet coil 2, and is used by being arranged in a place where the magnetic field generated by the magnet coil 2 is weak.

When the superconducting magnet device having such a structure is used in the permanent current mode, a current is supplied from the heater power source (not shown) to the heater wire 1b to generate heat, and the PCS coil 1a is in the normal conduction state ( After the switch is turned off), the magnet coil 2 is energized from the exciting power supply circuit 4, and when the current flowing through the magnet coil 2 and the magnetic field formed thereby stabilizes at a predetermined level, the heating of the heater wire 1b is stopped. . PCS coil 1a
Is cooled and reaches a superconducting state (switch ON state), the current from the excitation power supply circuit 4 is gradually reduced, and then the switch 3 is opened. As a result, a stable permanent current flows through the closed circuit of the magnet coil 2 and the PCS coil 1a for a long time even after being disconnected from the excitation power supply circuit 4.

In the above superconducting magnet device, the magnet coil 2 and the PCS coil 1a are made of NbTi.
A large number of alloy superconducting materials such as the above are embedded in a stabilizing matrix to make a fine wire, and a wire having a structure in which an outer surface is covered with an insulating layer is wound on a winding frame.
Here, the stabilization matrix, the temperature of the superconducting element wire is raised by some cause, to become a so-called quench state,
In order to quickly absorb the heat from the superconducting element wire and maintain the superconducting state, the stabilizing matrix of the magnet coil 2 and the PCS coil 1a,
It is made of a material with good thermal conductivity. However, the stabilizing matrix of the magnet coil 2 has a function of shunting a large amount of current flowing through the superconducting element wire into the stabilizing matrix when the coil 2 is quenched, so that the stabilizing matrix of copper, etc. Although it is composed of a material having good electrical conductivity, the wire of the PCS coil 1a is expected to act as a superconducting wire in the superconducting state and as a resistance wire in the normal conducting state, so that the PCS coil wire is stable. The chemical matrix is made of a material having a large specific resistance value such as a copper-nickel alloy. Therefore, the magnet coil 2 and the PCS coil 1a are connected in parallel by winding the superconducting wire rods designed and manufactured as separate bodies around separate winding frames in a coil shape and joining the lead-out ends of both coils to each other. . The winding and joining operations of these coils can be easily performed when the superconducting element wire is made of NbTi material.

[0006]

[Problems to be Solved by the Invention] Recently, demands for improving the performance of superconducting magnet devices have been increasing,
There has been a strong demand for the use of compound superconducting wires such as Nb ₃ Sn and V ₃ Ga, which have a very high critical current density in a high magnetic field as compared with NbTi superconducting wires. In particular, P
As described above, the superconducting wire for CS cannot use pure copper having a small specific resistance value as a stabilizing matrix because of its required function, and the superconducting state is easily destroyed even by a slight disturbance. In comparison, the use of compound superconducting wires such as Nb ₃ Sn and V ₃ Ga, which have a higher critical temperature and a large temperature margin, is expected. However, these compound-based superconducting wires are complicated to manufacture and
The superconducting characteristics deteriorate even with a slight strain, so careful handling is required. Also, joining of the lead-out portions of the magnet coil and the PCS coil is not easy after the compound superconductor is formed in the wire.

The present invention provides a superconducting magnet device which can stably maintain high performance by forming a magnet coil and a PCS coil using a compound type superconducting wire and is easy to manufacture, and a manufacturing method thereof. It is intended.

[0008]

A superconducting magnet device of the present invention comprises a winding frame having a magnet coil housing portion, a PCS coil housing portion and a lead wire joint portion housing portion, and a compound housed in the magnet coil housing portion. -Based superconducting wire magnet coil, compound-based superconducting wire PCS coil and heater wire housed in the PCS coil housing, and lead wire junction housing housing magnet coil and PCS coil housing A main feature of the present invention is to provide a wire joining portion, and a method for manufacturing a superconducting magnet device according to the present invention comprises winding a compound-based superconducting wire forming material for a magnet coil in a magnet coil housing portion of the winding frame, A compound-based superconducting wire forming material for a PCS coil and a heater wire are wound around the PCS coil housing part to After connecting the out line with each other, and heat-treating the whole, it is characterized in that to produce the compound superconductor in the two materials and the connecting portion.

[0009]

In the present invention, the magnet coil and the PCS are used.
Since the coils are both composed of compound-based superconducting wires, a superconducting magnet device having a high critical temperature and a very high critical current density in a high magnetic field can be obtained.
Further, the magnet coil, the PCS coil, and the lead wire joint are housed and fixed in the respective housings provided on the same winding frame, so that unreasonable force is applied during manufacturing or use to deteriorate the characteristics. There is nothing to do. Moreover, the production of the compound superconductor, which makes it difficult to handle and process the wire, is performed after the coil winding and the connection of the lead wire, so that the superconducting magnet device can be easily manufactured.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In these figures, the same parts as those in FIG. 2 are designated by the same reference numerals. FIG. 1 shows an embodiment of a superconducting magnet device of the present invention, in which a winding frame 10 is provided with flange portions 12 and 13 on the upper and lower sides of a cylindrical body 11, and two flange portions 12 and 13 are provided on the outer periphery of a lower thick flange portion 13. , The winding drum portion between the flange portions 12 and 13 forms a magnet coil housing portion 14, and the two annular grooves on the outer circumference of the lower flange portion 13 are lead wires. The joining portion storage portion 15 and the PCS coil storage portion 16 are formed. This reel is made of stainless steel, etc.
The inner walls of 4, 15 and 16 are insulation-treated by alumina spraying. Further, on the lower flange portion 13 of the reel,
Magnet coil housing 14 and lead wire joint housing 1
5 and between the lead wire joining portion housing portion 15 and the PCS coil housing portion 16 so as to guide the lead wire by gently curving, respectively, so that the spiral slit grooves 17, 1 are provided.
8 are formed.

Pure copper is used as a stabilizing matrix in the magnet coil housing 14 of the bobbin 10, and Nb ₃ Sn is used.
A superconducting wire having a superconductor is wound many times to form the magnet coil 2. Further, the PCS coil housing portion 16 contains a copper alloy such as C as a stabilizing matrix.
with u-10% Ni alloy, superconducting wire of the Nb ₃ Sn superconductor is while interposing the PCS heater wire 1b (not shown) to form a wound PCS coil 1a in a non-inductive winding . The superconducting wire for the magnet coil 2 and the superconducting wire for the PCS coil 1a, which are housed in the magnet coil housing portion 14 and the PCS coil housing portion 16, respectively, have extra length portions at the winding start end and the winding end end and a lead-out portion (not shown). And the extra length portion is wound up in the lead wire joint portion storage portion 15 as necessary, and then the tip ends of the lead portions are joined to each other by the joint portion 1.
They are joined together by 9. A lead wire 21 connects these joints and the terminal board 20. Although not shown, the winding frame 10, each coil 2,
1a, extra length portion, lead portion, joint portion 19 and lead wire 2
1 is integrated by impregnation with an epoxy resin.

In the above-described superconducting magnet device of the present invention, since the magnet coil and the PCS coil are both composed of a compound superconducting wire, the critical temperature is high and the critical current density in a high magnetic field is very high. Show the characteristics. Incidentally, when an excitation experiment was conducted using the above superconducting magnet device, it was possible to stably operate in the permanent current mode up to 10 Tesla. In addition, the magnet coil, PCS coil, and lead wire joint are housed and fixed in their respective housings provided on the same winding frame, so they are compact, and they do not require excessive force during manufacture or use. Does not deteriorate the characteristics.

Next, the manufacturing method of the present invention will be described. FIG.
In the case where the magnet coil 2 is provided on the winding frame 10, pure copper is used as the stabilizing matrix in the magnet coil housing portion 14, and the superconducting wire forming material for the magnet coil having Nb ₃ Sn as the superconductor is wound many times. To be turned. In addition, the PCS coil receiving portion 16, a copper alloy as a stabilizing matrix, for example using a Cu-10% Ni alloy, superconducting wire forming material for PCS coil 1a to the Nb ₃ Sn superconductor is, PCS heater wire 1b (Not shown)
It is wound by non-inductive winding while inserting. Here, the superconducting wire forming material means a wire material that has not been subjected to a heat treatment for producing Nb ₃ Sn. These superconducting wire forming materials can be manufactured by various methods such as a tube method, a bronze method, an internal diffusion method, an external diffusion method and an in situ method.

For example, when manufacturing a superconducting wire forming material for the PCS coil 1a using the tube method, as shown in FIG. 3, an Sn rod is incorporated into a Cu pipe (step S1) and cold drawing is performed. Wire drawing (step S
Perform 2) to make a copper clad tin rod. This copper clad tin rod is sequentially incorporated into an Nb pipe and a CuNi pipe (step S3), and drawn by cold drawing (step S4) to make a single wire having a hexagonal cross section. A large number of these single wires are incorporated into a CuNi pipe (step S5), hydrostatic extrusion (step 6) and wire drawing by cold drawing (step S7).
Is performed to obtain a wire having a circular or rectangular cross section. This strand is twisted (step S8), drawn again (step S9), and insulated (step S10) to obtain a PCS coil superconducting wire forming material. When manufacturing the superconducting wire forming material for the magnet coil by the tube method, a Cu pipe may be used instead of the CuNi pipe in the method of FIG.

The magnet coil superconducting wire forming material and the PCS coil superconducting wire forming material housed in the magnet coil housing portion 14 and the PCS coil housing portion 16, respectively, have extra lengths at the winding start end and the winding end end and a lead-out portion, respectively. To
It is drawn out through the slit grooves 17 and 18, is wound up in the lead wire joining portion housing portion 15, and the tips of the lead wire portions are connected to each other. For this connection, as shown in FIG. 4, the copper or copper alloy matrix layer at the tip of the protruding portion of the superconducting wire forming material 22 for the magnet coil 2 and the superconducting wire forming material 23 for the PCS coil 1a is melted and peeled off to be exposed. This is performed by making the tips of the single wires 22a and 23a intricately interpose each other, interposing Sn powder 24 between them, and caulking a Cu tube 25 covering the outside.

In this way, when the connection between the ends of the lead wires is completed, these connecting portions are put in the lead wire joining portion housing portion 15 as shown in FIG. Superconducting wire forming material for 2, PCS coil 1
Nb ₃ S for superconducting wire forming material for a and lead wire joints
Heat treatment is performed to generate n. In this heat treatment,
The superconducting wire forming material wound on the bobbin 10 and connected to the lead wire is put into a heating furnace and first heated to 300 to 400 ° C. to form a Cu—Sn layer, which is further 550 to 7
Heat to 80 ° C. to form a Nb ₃ Sn layer. At the time of this heat treatment, melting of the Sn powder 24 and reaction with the Cu tube 25 also perform solid-phase bonding between the tips of the lead-out portions. After that, the current lead wire 21 and the lead-out portion are connected by soldering or the like, and the entire reel is impregnated with epoxy resin and cured.

As described above, according to the method of manufacturing the superconducting magnet device of the present invention, the superconducting wire forming material which is not yet formed with the Nb ₃ Sn layer and has good workability is wound around the winding frame, and the lead-out portion is connected. After that, since heat treatment is applied to generate the Nb ₃ Sn layer, the production of the compound superconductor which makes the handling and processing of the wire difficult is performed after the coil winding and the connection of the lead wire, and Since the compound superconductor can be produced and the lead-out portion can be solid-phase bonded by one heat treatment, the superconducting magnet device can be easily manufactured. In the above description, the superconducting magnet device using Nb ₃ Sn as a superconductor as the compound superconducting wire has been described, but the present invention is not limited to this and other compound-based such as V ₃ Ga. It can be similarly applied to a superconducting magnet device using a superconducting wire. Also, the superconducting wire forming material is not limited to the above tube method,
It can be manufactured by various methods such as a bronze method, an internal diffusion method, an external diffusion method and an in situ method.

[0018]

As described above, in the superconducting magnet device of the present invention, since the magnet coil and the PCS coil are both composed of the compound superconducting wire, the critical temperature and the critical current density in a high magnetic field are high. Also, the magnet coil, PCS coil and lead wire joint are housed and fixed in their respective housings provided on the same winding frame, so unreasonable force is applied during manufacturing and use. Does not deteriorate. Moreover, in the method for manufacturing a superconducting magnet device of the present invention, since the production of the compound superconductor which makes the handling and processing of the wire difficult is performed after the coil winding and the lead wire connection, the coil winding and the lead wire connection The work is easy and there is little risk that the characteristics will deteriorate due to handling at the manufacturing stage.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a superconducting magnet device of the present invention.

FIG. 2 is a circuit configuration diagram illustrating a method of using the superconducting magnet device of the present invention.

FIG. 3 is a process diagram illustrating a manufacturing process of a PCS coil superconducting wire forming material in the method of the present invention.

FIG. 4 is a partial vertical cross-sectional view for explaining a connecting step of a magnet coil superconducting wire forming material and a PCS coil superconducting wire forming material in the method of the present invention.

[Explanation of symbols]

 1 ... PCS 2 ... Magnet coil 4 ... Excitation power supply circuit 5 ... Cryostat 10 ... Reel 11 ... Cylinder 12,13 ... Flange 14 ... Magnet coil storage 15 ... Lead wire joint Storage part 16 ...... PCS coil storage part 17, 18 ...... Slit groove 19 ...... Joining part 21 ...... Lead wire 22 ...... Magnetic coil superconducting wire forming material 23 ...... PCS coil superconducting wire forming material 24 ...... Sn Powder 25 …… Cu tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyo-shi Miyake 2-1-1 Oda Sakae, Kawasaki-ku, Kanagawa Prefecture 2-1-1 No. 1 Showa Electric Wire & Cable Co., Ltd.

Claims (4)

[Claims] 1. A winding frame having a magnet coil housing portion, a PCS coil housing portion, and a lead wire joining portion housing portion, a magnet coil made of a compound superconducting wire housed in the magnet coil housing portion, and the PCS coil. A superconducting device comprising: a PCS coil and a heater wire made of a compound superconducting wire housed in a housing part; and a lead wire joint part of the magnet coil and PCS coil housed in the lead wire joint part housing part. Magnet device. 2. The PCS coil accommodating portion and the lead wire joint accommodating portion accommodating portion are formed as concentric annular grooves on the outer circumference of one flange portion of the winding frame having the magnet coil accommodating portion. The superconducting magnet device described in. 3. The superconducting magnet device according to claim 2, wherein the lead wire joint portion storage portion is formed between the magnet coil storage portion and the PCS coil storage portion. 4. A compound superconducting wire forming material for a magnet coil is wound around a magnet coil housing portion of a reel, and a compound superconducting wire forming material for a PCS coil and a heater wire are wound around the PCS coil housing portion of the reel. A method for manufacturing a superconducting magnet device, which comprises winding and connecting lead wires of both materials to each other, and then heat-treating the whole to generate a compound-based superconductor in the both materials and the connecting portion.