JPS61265880A - Superconductive switch - Google Patents

Abstract

PURPOSE:To suppress the heater power to be necessiated for turning a superconductive switch into an OFF state to the minimum by a method wherein the upper part of the heat insulating container housing the superconductive gate conductors and the heater conductors is provided with a coolant path leading to the liquid helium container. CONSTITUTION:The upper part of a heat-insulating container 8 is provided with a coolant path 9 leading to a liquid helium container 2. When a superconductive switch 3 is turned to ON, a valve 10 is turned to OFF. Liquid helium 13 intrudes into between the winding parts of superconductive gate conductor 4 and the heat-insulating container 8, into cooling holes 6 and into the gaps between the windings of the superconductive gate conductors 4 and the superconductive gate conductors 4 are stably cooled and are held into a superconductive state. When the switch 3 is turned to OFF, the valve 10 is turned to ON and heater conductors 5 are conducted. When the heater conductors 5 are heated, the liquid helium 13 evaporate, and turned into an atmosphere of helium gas in the circumferences of the winding parts of the superconductive gate conductors 4. The superconductive gate conductors are easily heated and the superconductive switch 3 is turned to an OFF state.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to superconducting switches for use in superconducting magnet gold persistent current conditions.

[Technical background of the invention and its problems]

Conventionally, superconducting switches have thermal insulation R1 as shown in Figure 2.
The entire switch is immersed in a container of liquid helium.

Here, in the figure, 1 is the superconducting magnet body, 2 is the liquid helium container, 3 is the superconducting switch body, 4 is the superconducting wire that constitutes the superconducting switch, 5 is the heater wire for breaking the superconducting state, and 7 is the superconducting switch body. This is a winding frame for winding superconducting S. Reference numeral 12 denotes a thermal insulating layer for reducing the heater power required to break down the superconducting state, and is usually composed of a container such as FRP and an epoxy resin injected for impregnation.

Further, 13 is liquid helium.

However, this type of superconducting switch has the following problems. That is, since the superconducting wire 4 is insulated from the liquid helium, it is thermally extremely unstable, and the superconducting switch may quench.

[Purpose of the invention]

An object of the present invention is to provide a superconducting gate wire that can be stably cooled with 4-gold liquid helium when the switch is turned on, while minimizing the heater power required to completely destroy the superconducting state of the superconducting gate wire when the switch is turned off. The purpose is to provide a switch.

[Summary of the invention]

The gist of the present invention lies in the structure of a container that allows the superconducting gate wire to be immersed in liquid helium to cool it when the switch is turned on, and to place the superconducting gate wire in a helium gas atmosphere when the switch is turned off.

That is, in the superconducting switch according to the present invention, the container for insulating the superconducting gate wire and its winding portion from liquid helium is
The lower part is open to liquid helium, and the upper part is equipped with a refrigerant passage leading to the liquid helium container and a valve for opening and closing the passage.

When the switch is turned on, the valve is opened. The superconducting gate gland is immersed in liquid helium and is stably cooled. On the other hand, when the switch is turned off, the valve is closed and a superelectric current is applied to the heater wire wound together with the superconducting gate wire. When the heater wire is heated, the liquid helium in the tank evaporates and becomes helium gas, but since the valve at the top of the insulated container is closed, the helium gas begins to accumulate at the top of the insulated container, and finally In this case, the superconducting gate wire winding section is in a helium gas atmosphere, the superconducting state of the superconducting gate wire is broken, and the superconducting switch is turned off.

〔Effect of the invention〕

According to the present invention, the superconducting gate line can be cooled by immersion in liquid helium when the switch is turned on, and an extremely stable cooling state can be maintained. On the other hand, since a helium gas atmosphere exists around the superconducting date line when the switch is off, the heater power required to maintain the switch off state can be reduced.

[Implementation sequence of the invention]

Hereinafter, 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, 1 is a superconducting magnet, and the superconducting magnet 1 includes a liquid 1 a non-helium container 2
The superconducting switch 3 and the superconducting switch 3 are immersed in the Cc. Superconducting gate, l! 14 and the heater wire 5 are tightly wound around a winding frame 7 having cooling holes 6. The superconducting gate wire 4 winding portion is placed in a heat insulating container 8 whose lower part is open to liquid helium 13.
It is stored in. A refrigerant passage 9 communicating with the liquid helium container 2I and a valve 10 for opening and closing the passage 9 are provided at the upper part of the heat insulating container 8. A connecting wire 11 connecting the superconducting magnet 1 and the superconducting switch 3 is firmly fixed using the outer wall of the heat insulating container 8, the winding frame, etc.

When the switch 3 is turned on, the valve 10f is opened.

Liquid helium 13 enters between the 4 windings of the superconducting gate wire and the heat insulating container 8, the cooling hole 6, and the gap between the 4 windings of the superconducting date wire, so that the superconducting gate wire 4 is stably cooled and maintained in a superconducting state.

On the other hand, when the switch 3 is turned off, the valve 10 is closed and the heater wire 5 is energized. When the heater wire 5 is heated, the surrounding liquid helium 13 evaporates and becomes helium gas. However, since the valve 10 at the top of the heat insulating container 8 is closed, the helium gas accumulates in the top of the heat insulating container 8. Eventually, a helium gas atmosphere is created around the 4th winding of the superconducting gate wire, the superconducting gate wire is easily heated, the superconducting state is broken, and the superconducting switch 3 is turned off.

Note that the present invention is not limited to the first embodiment described above. For example, the material of the superconducting date wire and the material and shape of the heat insulating container may be determined as appropriate according to specifications. Further, as long as the heater power is large, the insulation properties of the insulation container do not matter. In addition, various modifications can be made within the scope of the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of a superconducting switch according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a schematic structure of a conventional superconducting switch. 19. . Superconducting magnet, 2...liquid helium container. 3... Superconducting switch body, 4... Superconducting wire, 5...
... Heater wire %8 ... Insulated container, 10 ... Valve,
12... Heat insulation layer. Representative Patent Attorney Noriyuki Chika (and 1 other person) Figure 1

Claims (3)

[Claims] (1) A winding section around which a superconducting gate wire and a heater wire for heating the gate wire are wound, a refrigerant passage that cools this winding section with liquid helium, and an insulating container that houses the winding section. A superconducting switch characterized by comprising: (2) The superconducting switch according to claim 1, wherein the heat insulating container has a heat insulating wall whose side and top sides are insulated from the liquid helium container, and whose lower side is open to the liquid helium. (3) The heat insulating container is equipped with a refrigerant passage leading to the liquid helium container in the upper part and a valve for opening and closing the passage, and the valve is opened when the switch is turned on and closed when the switch is turned off. A superconducting switch according to claim 1 or 2.