JPH0517853Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to the structure of a low-temperature terminal portion of a lead that supplies power from the outside of a low-temperature vessel housing a superconducting coil to the superconducting coil located inside.

[Conventional technology]

Generally, superconducting coils are housed inside a low-temperature container and are cooled and maintained at a cryogenic temperature by a cryogenic refrigerant such as liquid helium, so it is required to reduce the amount of liquid helium consumed. Therefore, it is necessary to reduce heat intrusion from the normal temperature part of the current lead to the superconducting coil part kept at an extremely low temperature.

Fig. 4 is a vertical cross-sectional view of a superconducting device using a conventional current lead for superconducting devices, and Fig. 5 is A--A in Fig. 4.
The structure will be explained based on a cross-sectional view taken in the direction of arrow A, FIG. 6 a longitudinal cross-sectional view of the low-temperature terminal portion in FIG. 4, and FIG. 7 a bottom view taken in the direction of arrow P in FIG. 6. A superconducting coil 2 is housed inside a low-temperature vessel 1, the opening is closed with a mounting lid 3, and liquid helium H is put inside to maintain the superconducting coil 2 at an extremely low temperature. The lead body 5 of the current lead 4 is provided by penetrating the mounting lid 3 with a shaft seal, and a room-temperature terminal portion 6 is attached to the mounting lid 3 at the upper position of the through hole 8 at one end of the outside of the container. A low temperature terminal section 7 is attached to the other end. The superconducting coil 2 inside the container has a lead wire 9
It is connected to the bus bar 10 of the low temperature terminal section 7 via. As is clear from the cross-sectional view shown in FIG. 5, the lead body 5 has a structure in which a plurality of conductive wires 12 are inserted into a hollow tube 11, and both ends of the conductive wire 12 are connected to a normal temperature terminal portion 6 and a low temperature terminal portion, respectively. Connected to 7 . In this lead body 5, helium gas h is passed through gaps 13 formed between the hollow tube 11 and the conducting wires 12 and between each conducting wire 12 to improve heat exchange. That is, in Fig. 4, the evaporated helium gas h
The gas flows inside the low-temperature terminal section 7 → inside the lead body 5 → inside the room-temperature terminal section 6, cooling the surface of the plurality of conductive wires 12 in the hollow tube 11, and then passing from the gas outlet pipe 14 of the room-temperature terminal section 6 to the outside. is released. This helium gas h has a function of removing Joule heat generated in the conductive wire 12 and conduction heat from the room temperature section. This function reduces the amount of heat that enters from the conducting wire 12 into the superconducting coil 2 and liquid helium H kept at an extremely low temperature.

The structure of the low-temperature terminal portion 7 of the current lead 4 is shown in FIG. 6, which is a vertical cross-sectional view, and in FIG.
Illustrated in the figure. This low-temperature terminal part 7 is formed by forming a conductor plate 18 on both open end surfaces of a cylindrical body 15 having a plurality of helium gas inflow holes 16 and a plurality of conductor connection holes 17.
and a ring plate 20 having a lead body through hole 19.
and are respectively closed to form a container for accommodating helium gas h. Further, the conductor plate 18 is provided with a bus bar 10, and the conductor 12 of the lead body 5 is provided with a bus bar 10.
are divided into a plurality of bundles from the end of the hollow tube 11, expanded radially, and inserted into the conductor connection holes 17 to be electrically connected to the conductor plate 18.

[The problem that the idea attempts to solve]

In addition to a plurality of conductor connection holes, a large number of helium gas holes are provided on the same plane in the conductor plate of the low-temperature terminal portion, so that the area of the conductor plate becomes large and the outer diameter of the cylindrical body also becomes large. For this reason, it is necessary to increase the inner diameter of the through hole in the mounting lid through which the current lead passes through when attaching and removing the current lead to the low temperature container. As a result, the area of the flange portion of the room-temperature terminal becomes large, radiant heat from the room-temperature section increases, and the consumption of liquid helium in the low-temperature container increases.

In view of the above-mentioned problems, this idea was developed by downsizing the low-temperature terminal part of the current lead, and in particular, by minimizing the outer diameter of the low-temperature terminal part and making the through-hole of the mounting lid and the normal-temperature terminal part smaller, it is possible to reduce the temperature of the current lead from the normal-temperature part. The purpose is to improve the structure of low-temperature terminals so as to reduce radiant heat.

[Means to solve the problem]

In this invention, in order to solve the above-mentioned problems, the structure of the low-temperature terminal part is reduced in outer diameter as follows. That is, a plurality of helium gas inflow holes are bored in the outer peripheral side wall surface of the cylindrical body constituting the low temperature terminal portion at the tip of the lead body in the low temperature container.

[Effect]

Multiple helium gas inflow holes are provided in the cylindrical body,
Since only the conductor connection holes are bored in the conductor plate, the outer diameter of the conductor plate and, therefore, the outer diameter of the cylindrical body can be reduced.

[Example] Fig. 1 is a vertical cross-sectional view of a low-temperature terminal portion of a current lead for a superconducting device that is an embodiment of this invention, Fig. 2 is a partial side view taken in the direction of the Q arrow in Fig. R in Figure 1
In the bottom view as viewed from the arrows, parts having the same functions as those of the prior art are designated by the same reference numerals and explanations thereof will be omitted.

In the embodiment of this invention, the helium gas inflow hole 16
A plurality of these are provided on the outer peripheral wall surface of the cylindrical body 15 that connects the conductor plate 18 and the ring plate 20 to form a helium gas container. As a result, the conductor plate 18
Only the conductor connection hole 17 needs to be drilled in the hole, and even if the bus bar 10 is provided, the area of the conductor plate 18 can be smaller than before, and the outer diameter of the cylindrical body 15 can be reduced. Therefore, the through hole 8 (see FIG. 4) of the mounting lid 3 can be made smaller, the flange portion of the room temperature terminal section 6 can be made smaller, and the radiant heat from the room temperature section can be reduced.

[Effect of idea]

According to this invention, the helium gas inflow hole is provided on the outer wall surface of the cylindrical body of the low-temperature terminal part, the area of the conductor plate is reduced, and the outer diameter of the cylindrical body is reduced, thereby making it possible to downsize the low-temperature terminal part and the room-temperature terminal part. . Along with this, radiant heat from the room temperature section can be reduced, and the amount of expensive liquid helium consumed can be reduced.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a low-temperature terminal portion of a current lead for a superconducting device that is an embodiment of this invention, Fig. 2 is a partial side view taken in the direction of the Q arrow in Fig. 1, and Fig. 3 is a partial side view of Fig. 1. R
4 is a vertical cross-sectional view of a superconducting device using a conventional current lead for a superconducting device, FIG. 5 is a cross-sectional view taken along the line A-A in FIG. 4, and FIG. 7 is a vertical cross-sectional view of the low-temperature terminal part in FIG.
FIG. 1... Low temperature container, 2... Superconducting coil, 4...
Current lead, 5... Lead body, 6... Room temperature terminal part, 7 ... Low temperature terminal part, 15... Cylindrical body, 16...
...Helium gas inflow hole.

Claims (1)

[Scope of utility model registration request] In the low-temperature terminal portion of the lead body that supplies power to the superconducting coil from the outside of the low-temperature container housing the superconducting coil, the low-temperature terminal portion is made of a cylindrical body installed inside the low-temperature container, and a plurality of the cylindrical bodies are arranged on the outer peripheral side wall surface of the lead body. A low-temperature terminal portion of a current lead for a superconducting device, characterized by having a helium gas inflow hole.