JPH02166705A - Manufacture of superconducting coil - Google Patents

Abstract

PURPOSE:To improve voltage resistance capacity, cooling capacity, and mechanical stability by passing a line material through a mixed resin bath of light and heat setting combination type which contains inorganic power as a filler, in the process to wind a superconducting coil, and whittling away resin which adhered excessively for adjustment of thickness, and then passing it through an ultraviolet ray irradiation bath so as to apply half setting treatment to the adhering mixed resin. CONSTITUTION:A superconductive line material 11A is soaked in a mixed resin bath 4, wherein quartz powder as an inorganic filler is mixed to light and heat-setting combination resin, through a guide roller 3. Since the mixed resin liquid 4A increases the viscosity by being mixed with quartz powder, a large amount of mixed resin liquid 4A adheres to the surface of the stabilizing material 10B of a superconductive line material 11B, though ununiform thickness, without unevenness. A thickness adjusting part 5 squeezes the mixed resin liquid 4A which adheres excessively by the surface pressure that is applied to the line material through a wiping-off pad, and continuously sends out a superconductive line material 11c which has a mixed resin liquid film 4B of uniform thickness and without unevenness. The mixed resin liquid layer 4B is gelatinized to the degree that the stickiness at the surface is lost by the ultraviolet irradiation of an ultraviolet irradiation device 5, and superconductive line material 11D, whereon a half set film 14 is formed, is wound round a coil winding drum 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a superconducting coil using a compound-based superconducting wire used in superconducting magnets, superconducting machines, etc.

[Conventional technology]

Niobium tritin (Nb38n), vanadium trigallium (
For compound superconducting wires made by covering thin wires such as V'3 Ga) with a stabilizing material such as copper or aluminum, the unreacted superconducting wires must be heat-treated at a high temperature of 500 to 1000°C. A superconducting compound is generated and functions as a superconducting wire, but in this way, K
The superconducting compound produced by this process is mechanically brittle, and when bending stress is applied to the wire during winding, it can cause problems such as breakage of thinner wires or a decrease in conductivity. A generally known method is to form a coil using a superconducting wire and then heat-treat it to impart superconductivity.

On the other hand, in recent years, a reacted compound-based superconducting wire that has been heat-treated while being wound around a wire drum with a minimum diameter d is wound in the direction of the winding pattern onto a coil frame with a diameter larger than the minimum diameter d to form a cylindrical or It has become known that an annular superconducting coil can be manufactured without damaging the superconducting compound, and its practical application is being considered.

By the way, a compound-based superconducting wire has a base material layer made by horizontally wrapping or braiding a tape made of an inorganic fiber 1 made of an expensive heat-resistant fiber such as quartz glass fiber or ceramic fiber, which can withstand heat treatment exceeding 500°C. The required voltage resistance and heat transfer performance can be obtained by impregnating and curing with heat, but since it is currently not possible to obtain an impregnated resin that can withstand the heat treatment, heat-treated superconducting resin with a base layer is used. After winding the wire and forming it into a coil,
Impregnation of the base material layer with resin and heat curing treatment of the impregnated resin are performed.

[Problem to be solved by the invention]

The conventional method of impregnating heat-treated superconducting wire with resin after winding requires a base material layer that can withstand heat treatment, and impregnation between the inorganic fibers through the gaps between the superconducting wires wound in alignment on the winding frame. It is extremely difficult to completely impregnate the resin, and unimpregnated areas and voids remain in the impregnated and heat-cured insulation coating layer, and thermal conductivity in these areas is inhibited, causing liquid helium to impregnate the resin. Cooling performance deteriorates, increasing the risk of quenching occurring where the superconductor is locally broken, and the insulation coating layer containing defects such as voids being unable to withstand the abnormal voltage that occurs due to quenching, leading to coil short-circuit accidents. Furthermore, since the mechanical strength of the insulation coating is low, improvements are required.

The purpose of this invention method is to form a resin insulating layer directly on the conductor surface without using a base material layer made of expensive heat-resistant fibers, thereby improving voltage resistance and cooling performance without defects such as voids.
and to obtain coil insulation with good mechanical stability.

[Means to solve the problem]

In order to solve the above problems, according to the method of the present invention, an unreacted compound-based super 1! A method of producing a cylindrical or annular superconducting coil having a diameter larger than the winding diameter on the wire drum by reacting a conductive wire material at a temperature of 500° C. or higher and then winding it around a coil winding frame in the same direction as the winding pattern. In the process of winding the reacted compound-based superconducting wire into a coil winding frame, it is immersed in a mixed resin liquid that is both light and heat-curable and contains inorganic filler powder, and the mixed resin liquid is layered on the conductor surface to remove any excess. After adjusting the thickness by removing the mixed resin liquid adhering to the coil, the mixed resin liquid is semi-cured by irradiating ultraviolet rays and wound onto the coil winding frame, and the semi-cured resin film is then heated. will be subjected to heat curing treatment.

[Effect]

In the above means, inorganic powder as a filler is added in the process of winding a superconducting coil by winding a reacted superconducting wire without a base material I wound around a wire drum onto a coil winding frame in the winding direction. After passing through a mixed resin bath containing original and heat-curing types, scraping off excess resin and adjusting the thickness, the mixed resin was semi-cured through an ultraviolet irradiation tank, so that the filler The mixed resin, whose viscosity has been increased by blending, forms a thin, uniformly thick semi-cured film directly on the conductor surface without dripping after adjusting the adhesion amount, so that the semi-cured film maintains the insulation gap during the process of being wound onto the coil frame. A uniformly maintained superconducting coil can be formed.

In addition, when the wound coil is heated and hardened, the semi-cured films are compressed together to fill the gaps between the superconducting wires, and the inorganic filler powder functions as a spacing material to maintain the spacing between the conductors. Upon curing, a superconducting coil is obtained which is integrated with a thin resin layer of uniform composition.

In addition, the thermal conductivity of the insulating layer in the obtained superconducting coil is improved by adding an inorganic filler, resulting in good cooling performance.On the other hand, the coefficient of thermal expansion is reduced, which reduces the thermal stress generated in the insulating layer due to temperature changes. is reduced, so it is mechanical.

It is possible to obtain a superconducting coil that has excellent stability in thermal characteristics and is therefore less likely to be quenched.

[Implementation f series]

The present invention will be explained below based on an example method.

FIG. 1 is a principle explanatory diagram showing an embodiment method of this invention.
FIGS. 2, 3, and 4 are cross-sectional views showing the state of the superconducting wire at each manufacturing step of the manufacturing method of the embodiment. In Fig. 1, 1 is a wire drum made of 4 made of gold with a winding core diameter d, and the unreacted compound superconducting wire is wound in an aligned manner and heat-treated at over 500°C, as shown in Fig. 2. Rather than showing the cross-sectional view, a bare superconducting m material 11A in which a superconducting compound is generated is formed in advance in the thin wire portion 10A in which the stabilizing material 10BK is embedded. Reference numeral 2 denotes a winding frame of a superconducting coil which is rotated by a winding machine in the direction of the arrow in the figure, and its diameter is formed to be larger than the diameter d of the winding core of the i-line drum 1. The direction of rotation with respect to the wire drum 1 is determined so that the superconducting wire 11A is wound in the winding direction.

3 is a guide roller for immersing the superconducting wire 11A in the mixed resin bath 4, and the mixed resin liquid 4A consists of 100 parts by weight of a light and heat curing resin as a base resin and average particles as an inorganic filler. For example, 100 parts by weight of quartz powder 'f with a diameter of 30 μm is used, and the base resin is Asahi Denka's Riva Taigu ES870 (epoxy type),
Type ES520 (acrylic and epoxy mixed system) manufactured by Toyobo Co., Ltd. is used. Mixed resin liquid 4A increases in viscosity by blending quartz powder, so mixed resin liquid 4
As shown in FIG. 6, a large amount of the mixed resin liquid 4A evenly adheres to the surface of the stabilizing material 10B of the superconducting wire 11B that has passed through the superconducting wire 11B with an uneven thickness.

The thickness adjustment section 5 is made of, for example, a felt wiping bat, and squeezes out the excess mixed resin liquid 4A by applying surface pressure to the wire rod through the bat, so that the adhesion thickness is, for example, 5.
Mixed resin liquid film 4B with uniform thickness of about 0 μm
The superconducting wire 11C having a superconducting wire 11C is continuously sent toward the ultraviolet irradiation device 5, and the mixed resin liquid layer 4B is gelled by the ultraviolet irradiation in a normal flow to such an extent that the surface adhesiveness is lost, and a semi-cured film 14 is formed. The superconducting wire 11D is wound around the coil frame 2.

Since the semi-cured film 14 of the superconducting wire 11D wound around the coil winding frame 2 in this manner is gel-like, the binding force applied by the aligned winding brings them into close contact with each other, and the entire coil is roughly coated, for example 15f:l'c. When the semi-cured film is heated to a certain degree and cured, it fuses with each other, and by the time the mixed resin has hardened after about 2 hours of heat treatment, a superconducting coil with the turns intertwined with the cured material of the mixed resin is formed. can get. The thickness of the semi-cured film 14 is reduced by the binding force applied between the turns during the heating and curing process, and the gap between the turns is filled accordingly. The quartz powder having an average particle diameter of about 304° C. acts as a spacing material to maintain the insulation distance between the turns at a predetermined dimension. Therefore, although the obtained superconducting coil does not include a base material layer made of heat-resistant fibers, it maintains the insulation thickness necessary to withstand voltage performance, and the adjacent turns are firmly fixed by a thin and uniform hardened layer of mixed resin. In addition, by incorporating a filler whose thermal conductivity is higher than that of resin, the heat transfer characteristics between turns are improved and excellent cooling performance is achieved. Since the thermal expansion coefficient of the superconducting coil becomes small, the thermal stress caused by temperature changes in the coil becomes small, and a superconducting coil with excellent thermal and mechanical stability can be obtained.

〔Effect of the invention〕

As described above, the method of this invention involves directly applying a thermosetting resin (mixed resin liquid) containing filler powder to the conductor surface of a heat-treated compound superconducting wire to form a semi-cured film with an adjusted thickness. The structure was such that it was heated and hardened after being wound onto a coil frame. As a result, the viscosity of the mixed resin liquid increases due to the addition of filler powder, and a large amount of resin liquid adheres evenly to the conductor surface. By adjusting the thickness and semi-curing the resin liquid, it is wound around the coil frame. A thin gel-like resin layer that adheres to each other is formed between the turns of the installed coil, and during the heat curing process, the filler powder acts as a spacing material and is integrated with the cured mixed resin of a predetermined thickness. To economically advantageously provide a superconducting coil having a desired withstand voltage performance without requiring a base material layer made of expensive heat-resistant fibers that can withstand high-temperature heat treatment exceeding 500°C. Can be done. In addition, since no base material layer is used, problems with impregnation in conventional methods are eliminated, and an insulating layer with fewer defects such as voids can be formed, and the thermal conductivity of the filler powder is significantly opposite to that of the resin. Since the obtained superconducting coil has a characteristic of having a small coefficient of thermal expansion, the obtained superconducting coil has excellent cooling performance and mechanical stability when cooling to an extremely low temperature, and therefore a superconducting coil with a low probability of quenching can be provided. .

[Brief explanation of the drawing]

Fig. 1 is a principle explanatory diagram showing an embodiment method of the present invention, and Figs. 2, 3, and 4 are cross-sectional views showing the state of adhesion of the mixed resin liquid to the superconducting layer material in the embodiment method. be. DESCRIPTION OF SYMBOLS 1... Electric wire drum, 2... Coil winding frame, 3... Guide roller, 4... Mixed resin bath, 4A, 4B... Mixed resin liquid, 5... Thickness adjustment section, 6... ...Ultraviolet irradiation device, 11A...NAt conductive wire (heat treated), 11B
...Superconducting wire with resin liquid attached, 11C...Superconducting wire with thin resin liquid film, 11D...Has semi-cured film No. 1, No. 2, No. 83, No. 4

Claims (1)

[Claims] 1) After reacting the unreacted compound-based superconducting wire wound around an electric wire drum at a temperature of 500°C or higher, it is wound onto a coil winding frame in the same direction as the winding pattern, and the winding diameter on the electric wire drum is In a method for manufacturing large-diameter cylindrical or annular superconducting coils, the reacted compound-based superconducting wire is immersed in a photo-curable and heat-curable mixed resin liquid containing inorganic filler powder during the process of winding the reacted compound-based superconducting wire into a coil winding frame. The mixed resin liquid is applied to the conductor surface, the thickness is adjusted by removing the excess mixed resin liquid, and then the coil winding is completed through a process of semi-curing the mixed resin liquid by irradiating ultraviolet rays. A method for manufacturing a superconducting coil, which comprises winding it into a frame and subjecting the latter half-cured resin film to heat curing treatment.