JPS62229905A - Superconducting magnet - Google Patents

Abstract

PURPOSE:To transmit the heat created in the center part of a winding quickly to cool the winding and improve the characteristics of superconducting coil by a method wherein a coil cooling layer is provided on the internal surface of the winding and internal coil cooling layers made of maferial with a high heat conductivity are provided so as to be contacted with the coil cooling layer and inserted into the winding of the superconducting coil. CONSTITUTION:A coil cooling layer 9 is provided on the internal surface of the winding of a superconducting coil 3 and internal coil cooling layers 10 and 10' made of material with a high heat conductivity such as copper are provided so as to be contacted with the coil cooling layer 9 and inserted into the winding vertically. The loss heat created inside the coil by friction, magnetization and demagnetization is transmitted from the internal cooling layers 10 and 10' wrapped and inserted into the coil to liguid helium in a cooling chamber 8 fhrough the coil cooling layer 9 formed on the internal surface of the coil winding 14 and an internal chamber partition plate 1B and the winding can be cooled faster than wifh the constitution in which the cooling layer is not provided inside the coil.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) This invention relates to a superconducting magnet used in a superconducting magnetic levitation railway or the like.

(Prior Art) Currently, superconducting magnetic levitation railways are being developed as a future means of transportation.

The superconducting magnets used in this superconducting magnetic levitation railway are
The structure is such that an inner tank housing a superconducting coil is held within an outer tank, which is a vacuum container.

An important issue in the development of superconducting magnetic levitation railways is making superconducting magnets lighter and more compact. Conventionally, a method for making superconducting magnets lighter and more compact has been to improve the current density in the windings. On the other hand, by shortening the distance between the vehicle-side superconducting coil and the ground-side coil, the magnetomotive force of the superconducting coil can be lowered, thereby making it possible to make the superconducting coil lighter and more compact. This will be explained using the cross-sectional view of the vehicle in FIG.

When a vehicle 13 equipped with a superconducting coil 11 runs on a levitation coil 12 installed on a track, an electromagnetic induction repulsive force is generated between the two coils 11 and 12, and the vehicle 13 levitates. The magnetomotive force of the superconducting coil 11 necessary to obtain this levitation blade is related to the distance Y between the center of the superconducting coil 11 and the center of the levitation coil 12 on the ground, and the smaller this distance Y is, the smaller the magnetomotive force is. good. In order to make the distance Y as small as possible, conventionally a coil with a flat cross section was used.
Inner tanks have been adopted. A specific example of this is the structure shown in FIGS. 6 and 7.

This superconducting magnet has an annular (racetrack-shaped) inner tank 1, a plurality of reinforcing members 2 are integrally attached to the inside of the inner tank 1, and a superconducting coil 3 is installed in the center of the inner tank 1.
is installed. This superconducting coil 3 is made by winding a superconducting wire multiple times together with an interlayer insulating layer, and then providing an insulating layer 4 on the outside and integrally impregnating and insulating it to strengthen the rigidity.
Spacer pieces 5 having a plurality of holes 6 and notches 7 are arranged at appropriate intervals inside the superconducting coil 3 to hold the superconducting coil 3 therein. As a cooling method for the coil 3, the spacing piece 5
A so-called ambient immersion cooling method is used, which utilizes the holes 6 and cutouts 7.

However, in the above structure, since the spacing piece 5 is interposed between the inner tank 1 and the superconducting coil 3, there is a limit to making the superconducting magnet compact and shortening the distance between the coil centers (distance Y shown in Fig. 9). There is.

Therefore, an inner tank structure was devised that eliminates the spacer piece 5 that fixes the coil and makes the superconducting magnet more compact.

An example of this is shown in FIG.

This FIG. 8 is a partial sectional view similar to FIG. 7 taken along the line ■-■ in FIG. and partition plates IB and IC, which are mounted between the two side plates and displaced toward the inner circumferential side of the track.
A cooling chamber 8 filled with liquid helium is formed, and an annular groove-shaped winding portion 14 surrounded by side plates IA, IA' and partition plates IB is formed on the outer periphery of the chamber 8. Then, after winding a superconducting wire in this groove-shaped winding part 14 to form a superconducting coil 3, a winding part cover I is attached to an outer peripheral opening of the winding part 14.
D is covered and fixed by welding, and after assembly, the winding portion 14 is integrally impregnated and insulated.

Note that 4 in the figure is an insulating layer that covers the outside of the superconducting coil 3.

In the case of this inner tank structure, the liquid helium filling cooling chamber 8
However, unlike the conventional cooling method (immersion method that covers the entire circumference of the superconducting coil 3) shown in FIG. 6 and FIG. It will be placed in That is, since the cooling chamber 8 is provided on the inner circumferential side of the track of the racetrack-shaped inner tank 1, the distance between the coil centers and the levitation coil on the ground side (Y shown in FIG.
distance) can be significantly reduced.

However, the partition plates IB and IC are usually made of stainless steel, and the superconducting coil 3 is cooled by the partition plates IB and IC.
Since the cooling chamber 8 is filled with liquid helium,
In the coil portion 3A farthest from the coil 3, the cooling capacity was insufficient for frictional heat and loss heat generated in the superconducting wire during coil excitation and demagnetization, which caused the coil 3 to quench.

As a method to solve this problem, a coil cooling layer 9 formed by depositing a film of a material with high thermal conductivity, such as copper, on the inner surface of the coil winding portion 14 as shown in FIG. There is a method in which the entire circumference of the coil is uniformly cooled by heat conduction through the coil cooling layer 9 (see FIG. 5).

The thermal conductivity of copper is about 60 compared to that of stainless steel.
00 times, the thickness of the partition plate IB is 5M.

Even if the copper layer thickness is 0.05 m, heat conduction is 60 times greater. Therefore, the inner surface of the coil winding portion 14 has a thickness of 0.
By forming the coil cooling layer 9 coated with copper with a thickness of about 0.5 m, it is possible to quickly cool the superconducting coil 3 from all around it.

However, as shown in FIG. 5, even if a copper coil cooling layer 9 is formed on the inner surface of the winding section to cool the entire circumference of the coil, the central part 3B of the winding of the superconducting coil 3 is
It is insufficient for cooling when heat is generated. This is because frictional heat generated in the center of the superconducting coil 3,
The heat loss due to excitation and demagnetization is caused by the Nb constituting the superconducting wire.
T1.

The heat is transferred to the liquid helium in the cooling chamber 8 through the Cu, the epoxy resin impregnated between the superconducting wires, the inner tank 1 and the stainless steel partition plate IB, so that the superconducting coil 3
It will take some time for the central part 3B of the cylinder to cool down. That is, if heat is generated in the central portion 3B of the coil in a short period of time, cooling will not be done in time, and the coil will be quenched due to the heat generation.

(Problems to be Solved by the Invention) The conventional technology is as described above, in which the heat generated at the center of the winding of a superconducting coil is quickly transferred and cooled, and the coil quenching due to heat generation at the center of the coil is prevented. Couldn't solve the problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a superconducting magnet in which the heat generated at the center of the winding of a superconducting coil is quickly transferred and cooled, thereby improving the characteristics of the superconducting coil.

[Structure of the invention]

(Means and effects for solving the problem) This invention inserts a coil internal cooling layer made of a material with high thermal conductivity inside the winding of a superconducting coil, and this coil internal cooling layer is formed on the inner surface of the winding part. By connecting to the coil cooling layer, the frictional heat generated inside the coil and the heat lost during excitation/demagnetization are quickly transferred to the liquid helium in the cooling chamber, improving the characteristics of the superconducting coil. shall be.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. In the figure, reference numeral 1 denotes a racetrack-shaped inner tank held in an outer tank (not shown), which is a vacuum container, and the structure of this inner tank is similar to the conventional example shown in FIG. That is, the inner tank 1 has annular side plates IA, IA' spaced apart from each other in the front and back.
and partition plates IB and IC made of stainless steel, which are mounted between the two side plates and displaced toward the inner circumferential side of the track, and a cooling chamber 8 filled with liquid helium is formed by the partition plates IB and IC. and both side plates IA are attached to its outer periphery.
, IA' and partition plate IB.
4 is formed on the inner surface of the winding portion 14, a coil cooling layer 9 of a material with high thermal conductivity 1, for example, copper is formed as a coating on the inner surface of the winding portion 14, and a superconducting wire is formed in the internal space of the winding portion 14. A superconducting coil 3 is disposed in which the superconducting coil 3 is wound and impregnated with epoxy resin, an insulating layer 4 is provided covering the outside of the superconducting coil 3, and a winding is fixed by welding after the superconducting coil 3 is wound. Equipped with line part cover ID,
The above configuration is the same as the inner tank structure shown in FIG.

Therefore, the present invention provides a superconducting magnet of the indirect cooling type as described above, which has a high thermal conductivity that is connected to the coil cooling layer 9 on the inner surface of the winding part and inserted vertically into the inside of the winding of the superconducting coil 3. Coil internal cooling layer 10.1 made of material, e.g. copper
0' is provided.

When such a coil internal cooling layer 10.10' is provided,
Frictional heat generated inside the coil and heat loss due to excitation/demagnetization are absorbed by the internal cooling layer 10, which is wound and inserted inside the coil. t
The heat is transferred from o' through the coil cooling layer 9 formed on the inner surface of the coil winding part 14, through the inner tank partition plate IB, to the liquid helium in the cooling chamber 8, and there is no cooling layer inside the coil. Cools down faster than usual. This makes it possible to prevent quenching occurring from inside the coil due to frictional heat inside the coil and heat loss due to excitation/demagnetization, and it becomes possible to improve the characteristics of the superconducting coil.

In addition, FIG. 2 shows a cooling layer 10 vertically inside the coil.
．． Although the embodiment has been described in which the cooling layer 10 and 10' are provided, the cooling layer 10 and 10' may be inserted inside the coil laterally as shown in FIG. The rest of the structure in this embodiment is the same as that in the embodiment shown in FIG. 2, so the same parts are given the same reference numerals and a detailed explanation will be omitted.

In the case of the embodiment shown in FIG. 3 described above, the heat generated inside the coil is absorbed by the cooling layer 1 inserted laterally inside the coil.
Since heat is transferred from 0.10' through the coil cooling layer 9 formed on the inner surface of the coil winding part 14, the heat transfer distance is longer than that of the embodiment shown in FIG. 2, and the cooling performance is as shown in FIG. Although it is slightly worse than the case of 2, it has the advantage that it is easy to insert and wind the internal cooling layer 10, 10' during coil winding.

FIG. 4 shows an example in which an internal cooling layer 10 is provided as a cooling layer 10 inside the coil so as to intersect with the vertical and horizontal directions of the coil 3, and the other configuration is the same as the embodiment shown in FIGS. 2 and 3. Since they are similar, the same parts will be given the same reference numerals and detailed explanation will be omitted.

[-Effect of ease]

According to the present invention, it is possible to prevent quenching due to heat generation inside the coil, which has conventionally been one of the causes of deterioration of the characteristics of superconducting coils, and to improve the characteristics of superconducting coils.

[Brief explanation of drawings]

FIG. 1 is an overall front view showing a superconducting magnet of the present invention, FIG. 2 is an enlarged sectional view taken along the l=X line in FIG. 1, and FIGS. 3 and 4 are other embodiments of the present invention. Fig. 5 is a partial sectional view showing a conventional superconducting magnet, Fig. 6 is an overall front view showing a conventional directly cooled superconducting magnet, and Fig. 7 is an enlarged sectional view of a portion corresponding to Fig. 2. FIG. 6 is an enlarged sectional view taken along the line ■-■ in FIG. 6, FIG. 8 is a partial sectional view showing a conventional indirectly cooled superconducting magnet, and FIG. 9 is a sectional view of the track configuration including a vehicle. 1... Racetrack-shaped inner tank, IA, IA'...
・Inner tank side plates, IB, IC...Inner tank partition plate, ID...
- Winding section cover, 3... Superconducting coil, 4... Insulating layer, 8... Liquid helium filling cooling chamber, 9... Coil cooling layer, 10.10'... Coil internal cooling layer ,1
4...Coil winding section. Applicant's Representative Patent Attorney Takehiko Suzue Figure 19 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] It is a racetrack-shaped inner tank held in an outer tank that is a vacuum container, and has a cooling chamber filled with liquid helium on the inner circumference of the track, a winding section on the outer circumference of the track, and A coil cooling layer made of a material with high thermal conductivity formed as a film on the inner surface of the winding part of the tank, a superconducting coil formed by winding a superconducting wire inside the winding part, and welding after the winding of this superconducting coil. In an indirectly cooled superconducting magnet equipped with a fixed winding part cover, the inside of the coil made of a material with high thermal conductivity is connected to the coil cooling layer on the inner surface of the winding part and inserted inside the winding of the superconducting coil. A superconducting magnet characterized by having a cooling layer.