JPS624382A - Superconductive switch - Google Patents

Abstract

PURPOSE:To obtain the superconductive switch of indirect cooling system which can be arranged in a vacuum without immersion in liquid helium by cooling a winding part of the superconductive wire by a cooling medium flowing pipe through a heat resistance body. CONSTITUTION:A superconductive winding part 11 wound cylindrically is surrounded by a winding peripheral part consisting of a good heat conductor. In the center axis of said winding part 11, a cooling medium flowing pipe 13 for passing a cooling medium such as liquid helium is arranged. Also, a heat resistance body 14 is arranged between the flowing pipe 13 and the peripheral part 12 and it connects them thermally. The whole of them is arranged in a vacuum. By this constitution, the winding part 11 can be cooled by liquid helium flowed in the flowing pipe 13 through a heat resistance body 14, thereby switching the superconductive switch on.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a superconducting switch used in a superconducting magnet, and more particularly to an indirect cooling type superconducting switch.

[Technical background of the invention and its problems]

Conventionally, a superconducting switch is cooled by being entirely immersed in liquid helium as shown in FIG. That is, a superconducting switch is constituted by a conductive wire winding section 31 and a heat insulating wall 32 surrounding it made of a heat insulating material such as epoxy resin, and the entire switch is cooled by being immersed in liquid helium. It was a cooling system. In the figure, 33 indicates a superconducting wire lead, and 34 indicates a heater wire lead.

However, small types of switches have the following problems. That is, when connecting this switch to an indirectly cooled superconducting magnet, the leads of the switch must be led into a vacuum through an insulated airtight terminal. For this reason, it was necessary to use special parts for connection to the superconducting magnet, and the connection was extremely troublesome.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to provide an indirect cooling type superconducting switch that can be placed in a vacuum without being immersed in liquid helium. It is in.

[Summary of the invention]

The gist of the present invention is to cool the winding portion of a superconducting wire through a thermal resistor using a coolant flow tube such as liquid helium.

That is, the present invention provides an indirect cooling type superconducting switch that includes a winding section formed by winding a superconducting wire, and a winding section made of a good heat conductor that surrounds this winding section and uniformizes the temperature of the winding section. a wire outer peripheral portion; a heater portion for heating the winding portion;
It comprises a refrigerant flow pipe disposed close to the 11th section and through which a refrigerant flows, and a thermal resistor section provided between the passage tube and the outer peripheral part to thermally connect them. It is what it is.

In addition to the above configuration, the present invention further provides a heat diffusing body made of a good thermal conductor in the winding portion.

〔Effect of the invention〕

According to the present invention, it is possible to realize an indirect cooling type superconducting switch, so if the superconducting magnets to be connected are of the indirect cooling type, it is only necessary to connect the mutual leads in a vacuum, making the connection extremely easy. Furthermore, by arranging the heat diffuser within the winding section, even if there is local heat generation within the winding section, this heat can be diffused throughout. Therefore, it is possible to prevent inconveniences such as the superconducting switch not returning to the superconducting state due to power supply ripples or the like.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a sectional view showing a schematic structure of a superconducting switch according to an embodiment of the present invention. In the figure, reference numeral 11 denotes a winding section of a superconducting wire wound into a cylindrical shape. It is surrounded by a winding outer peripheral part 12 consisting of a body. Note that a heater wire (not shown) is also wound around the winding portion 11.

A refrigerant flow pipe 13 for passing a refrigerant such as liquid helium is arranged on the central axis of the winding a1111.

A thermal resistor 14 made of a material with poor thermal conductivity, such as phosphorus-deoxidized copper, is located between the flow pipe 13 and the winding outer peripheral portion 12.
The winding outer peripheral portion 12 and the flow pipe 13 are thermally connected by this thermal resistor 14 .

The entire structure is placed in a vacuum. In the figure, 15 indicates a lead of the superconducting wire wound around the winding portion 11, and 16 indicates a lead of the heater wire.

With the above configuration, the winding portion 11 can be cooled to an extremely low temperature via the thermal resistor 14 by liquid helium flowing into the coolant flow pipe 13, and thereby the superconducting switch can be turned off.
Can be N. Furthermore, when current is applied to the heater wire in this state, the winding portion 11 of the superconducting wire is heated, and the winding portion 1
1 undergoes a normal conduction transition, which allows the switch to be turned off. Here, the thermal resistor 14 has the role of reducing the escape of heat from the winding part 11 to the refrigerant flow pipe 13 when the heater wire is energized, and the role of reducing the escape of heat from the winding part 11 to the refrigerant flow pipe 13 when the heater wire is not energized. It plays the role of dissipating the heat of the winding part 11 to the refrigerant flow pipe 13 so that it is cooled to an extremely low temperature.

As described above, according to this embodiment, an indirect cooling type superconducting switch can be realized. In this case, when used in connection with an indirectly cooled superconducting magnet or the like, the connection can be easily made without using a special insulated hermetic terminal. Furthermore, since the leads of the superconducting wire and the heater wire from the winding section 11 can be taken out into a vacuum, the structure of the lead extraction section can be simplified compared to a conventional switch in which these leads are taken out into liquid helium. obtain.

FIG. 2 is a sectional view showing a schematic structure of another embodiment.

This embodiment differs from the previously described embodiments in that a heat spreader is disposed within the winding portion 11. That is, a plurality of heat diffusion plates 21 made of the same material as the outer peripheral part 12 are arranged within the winding part 11 . The heat diffusion plate 21 is formed into a cylindrical shape, for example, and is arranged coaxially with the winding portion 11.

Then, when heat is generated locally within the winding portion 11,
This heat is diffused throughout the winding portion 11.

With such a configuration, not only the same effects as in the previous embodiment but also the following effects can be obtained.

That is, in the structure shown in FIG. 1, the heat generated near the center of the winding portion 11 is difficult to escape.

For this reason, there is a possibility that the entire winding section may not be able to return to superconductivity from a normal conduction state even due to slight self-heating or the like. Also,
A similar situation may occur due to self-heating caused by a small amount of current, such as current ripple.

In contrast, in this embodiment, even if heat is generated locally, it can be diffused throughout the winding portion 11 by the heat diffusion plate 21. Therefore, it is possible to prevent inconveniences such as not being able to return from a normal conductive state to a superconducting state due to power supply ripples or the like. In other words, ripple regulations can be relaxed when designing a power supply. Further, in cooling, the presence of the heat diffusion plate 21 has the advantage that the central portion of the winding portion 11 can also be cooled quickly.

Note that the present invention is not limited to the embodiments described above. For example, the material of the thermal resistor may be appropriately selected depending on the temperature at which the winding portion is to be cooled and the optimum heat generation condition of the heater portion.

Further, the heater does not necessarily have to be wound around the winding section, but may be any heater that can heat the superconducting wire forming the winding section to the extent that it undergoes a normal conduction transition.

Furthermore, the refrigerant flowing through the refrigerant flow pipe is not limited to liquid helium, but may be any refrigerant as long as it has a temperature close to cryogenic temperatures. Moreover, as a diffuser in the embodiment shown in FIG.
It is possible to use copper plain braided wire. In this case, when the winding portion is impregnated with resin, the resin penetrates easily, which is advantageous. In addition, without departing from the gist of the present invention,
Various modifications can be made.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a schematic structure of an indirect cooling type superconducting switch according to one embodiment of the present invention, FIG. 2 is a sectional view showing a schematic structure of another embodiment, and FIG. 3 is a conventional superconducting switch. FIG. 11... Superconducting wire winding part, 12... Winding outer peripheral part, 1
3... Refrigerant flow pipe, 14... Heat resistor, 15...
Superconducting wire lead, 16... Heater wire lead, 21...
・Thermal resistor. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (7)

[Claims] (1) A winding part formed by winding a superconducting wire, a winding outer peripheral part made of a good heat conductor that surrounds this winding part and uniformizes the temperature of the winding part, and a winding part formed by winding a superconducting wire. A heater section for heating, a refrigerant flow tube disposed close to the winding section and through which a refrigerant flows inside, and a refrigerant flow tube provided between the flow tube and the outer peripheral section to thermally connect these. A superconducting switch characterized by comprising a thermal resistor section. (2) The superconducting switch according to claim 1, wherein the heater section is made of a heater wire that is wound together with the superconducting wire around a winding section of the superconducting wire. (3) The superconducting switch according to claim 1, wherein liquid helium is used as the refrigerant flowing through the refrigerant flow pipe. (4) A winding part formed by winding a superconducting wire, a winding outer peripheral part made of a good heat conductor that surrounds this winding part and uniformizes the temperature of the winding part, and a winding part formed by winding the winding part. A heater section for heating, a refrigerant flow pipe arranged close to the winding part and through which a refrigerant flows inside, and a refrigerant flow pipe provided between the flow pipe and the outer peripheral part to thermally connect these. A superconducting switch comprising: a thermal resistor; and a thermal diffuser made of a good thermal conductor disposed in the winding. (5) The superconducting switch according to claim 4, wherein the heater section is made of a heater wire that is wound together with the superconducting wire around the winding section of the superconducting wire. (6) The superconducting switch according to claim 4, wherein liquid helium is used as the refrigerant flowing through the refrigerant flow pipe. (7) The superconducting switch according to claim 4, wherein the heat spreader is made of a copper plain braided wire.