JPH02299458A - Cold terminal section of superconductive device current lead - Google Patents

Abstract

PURPOSE:To reduce a consumption a liquid helium contained in a cryostat by forming a helium gas inflow space between the circumferential surface of a cylindrical body and the peripheral surface of a conductor disc. CONSTITUTION:A helium (h) inflow place to the inside of a cold terminal section 7 is a space 26 formed between the circumferential surface of a cylindrical body 15 and the peripheral surface of a conductor disc 28. Accordingly, it is not necessary to provide a helium gas inflow hole to the conductor disc 28, and an area of the conductor disc 28 can be reduced. That is, the outside diameter of the conductor disc 28 can be reduced, so that the outside diameter dimension of the cylindrical body 15 can also be reduced accordingly. According to the constitution, radiant heat from a normal temperature section can be reduced, and a consumption of liquid helium in a cryostat 1 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a low-temperature terminal portion of a current lead that supplies power from the outside of a low-temperature container housing a superconducting coil to the superconducting coil located inside.

[Conventional technology]

Generally, a superconducting coil is housed inside a cryogenic container, and is cooled and maintained at a cryogenic temperature by a cryogenic refrigerant such as liquid helium. In this case, since liquid helium, which is a cryogenic refrigerant, is expensive, it is required to minimize its consumption. 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. 3 is a vertical cross-sectional view of a conventional superconducting device using a flow lead, Fig. 4 is a cross-sectional view taken along the line A-A in Fig. 3, and Fig. 5 is a low-temperature terminal section in Fig. 3. Longitudinal cross-sectional view, No. 6
The figure is a cross-sectional view taken along arrow P in FIG. 5, and the structure of the superconducting device will be explained based on these drawings. Store the superconducting coil 2 inside the low temperature container l and attach the opening! 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 normal temperature terminal part 6 is attached to one end outside the container at the upper position of the through hole 8, and the other end inside the container is A low temperature terminal section 7 is attached. The superconducting coil 2 inside the container is connected to the bus bar 10 of the low temperature terminal section 7 via the outlet &119. The structure of the lead body 5 is the fourth
As is clear from the cross-sectional view shown in the figure, a plurality of conductive wires 12 are inserted into the hollow tube 11, and both ends of the conductive wires 12 are connected to room-temperature terminal portions 6. It is connected to the low temperature terminal section 7. In this lead body 5, between the hollow tube 11 and the conductive wire 12 and each conductor! 1
Helium gas h is passed through the gap 13 formed between the two to improve heat exchange. That is, in FIG. 3, the evaporated helium gas h flows through the inside of the low-temperature terminal section 7 and the inside of the lead body 5, cools the surfaces of the plurality of conducting wires 12 in the hollow tube 11, and enters the inside of the room-temperature terminal section 6. The gas is discharged to the outside from the gas outlet pipe 14. This helium gas h has a function of removing the Joule heat generated in the conductor 112 and the conductive heat from the normal temperature section. Guided by this feature!
The amount of heat that enters the superconducting coil 2 and the liquid helium H from the superconducting coil 2 held at an extremely low temperature is reduced.

The structure of the low-temperature terminal portion 7 of the current lead 4 is shown in the longitudinal cross-sectional view of FIG. 5 and in FIG. 6, which is a cross-sectional view taken along the line B--B of FIG. 5. This low-temperature terminal section 7 has a conductor disk having a plurality of helium gas inflow holes 16 and a plurality of conductor connection holes 17 at both open ends of the cylindrical body 15, and a lead body through hole 19.
and a ring plate 20 having helium gas h
It forms a container that accommodates. Furthermore, the conductor disk 1
8 is provided with a bus bar 10, which connects the conductor 1 of the lead body 5.
2 is divided into a plurality of bundles from the end of the hollow tube 11, expanded radially, and inserted into the conductor connection hole 17, and then connected to the conductor plate 1.
electrically connected to the sun.

[Problem to be solved by the invention]

In addition to multiple conductor connection holes, the conductor disc of the low-temperature terminal section has many helium gas inflow holes on the same plane, so the area of the conductor plate becomes large, and the outer diameter of the cylinder 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. Therefore, the area of the flange part of the normal temperature terminal becomes large, and the radiant heat from the normal temperature part increases.
There was a problem in that the amount of liquid helium consumed in the cryogenic container increased.

In view of the above-mentioned problems, an object of the present invention is to miniaturize the low-temperature terminal part of the current lead, and in particular to minimize the outer diameter of the low-temperature terminal part to make the through-hole of the mounting lid and the normal-temperature terminal part small. The object of the present invention is to improve the structure of the low-temperature terminal section so as to reduce the radiant heat from the terminal section.

[Means to solve the problem]

In this invention, the helium gas inflow structure in the low-temperature terminal portion is as follows. In other words, a ring plate at the tip of the lead body that supplies power from the outside to the superconducting coil inside the low-temperature container that houses the superconducting coil, through which the lead body passes, and a conductor that supports a bus bar that connects the lead wire of the superconducting coil. In a low-temperature terminal section composed of a disk and a cylindrical body into which the conductor disk and the ring plate are respectively fitted into both opening ends, the inner circumferential surface of the cylindrical body and the outer circumferential surface of the conductor disk are A helium gas inflow space was formed between them.

[Effect]

By providing a helium gas inflow space between the inner circumferential surface of the cylindrical body and the outer circumferential surface of the conductor disk, there is no need to provide a helium gas inflow hole in the conductor disk, and only a conductor connection hole is required. The outer diameter of the conductor disk can be made smaller than before, and the outer diameter of the cylindrical body can be made smaller accordingly.

〔Example〕

FIG. 1 is a vertical cross-sectional view of a low-temperature terminal portion of a current lead for a superconducting device according to an embodiment of the present invention, and FIG.
In the cross-sectional view taken in the direction of arrows, parts having the same functions as those of the conventional low-temperature terminal shown in FIGS. 5 and 6 are designated by the same reference numerals, and their explanations will be omitted.

This embodiment differs from the conventional example in the mounting structure between the cylindrical body 15 and the conductor disk 28. That is, the outer diameter of the conductor disk 2B having the bus bar 10 and the conductor connection hole 17 is smaller than the inner diameter of the cylindrical body 15, and the conductor disk 28 is connected to the cylindrical body 15.
If it is fitted into the open end of the cylindrical body 15 and attached from the outer periphery of the cylindrical body 15 with the mounting screws 21, a space 26 is formed between the inner circumferential surface of the cylindrical body 15 and the outer circumferential surface of the conductor disc 28.

From this space 26, helium gas h can flow into the cylindrical body 15 in the direction of the arrow. Therefore, it is not necessary to provide a helium gas inflow hole in the conductor inner plate 28, and only the conductor connection hole 17 is provided, and even if the bus bar 10 is provided, the area of the conductor disk 28 can be smaller than before, and the outer diameter dimension can be reduced. Can be made smaller. Therefore, it is possible to reduce the outer diameter of the cylindrical body 15. When the outer diameter of the low-temperature terminal section 7 is reduced, the through hole 8 (FIG. 3) of the mounting section 13 can also be made smaller, and the flange portion of the normal-temperature terminal section 6 can also be made smaller, thereby reducing radiant heat from the normal-temperature section.

〔Effect of the invention〕

In this invention, since the helium gas inflow point into the low-temperature terminal part is the space formed between the inner circumferential surface of the cylindrical body and the outer circumferential surface of the conductor disk, it is not necessary to provide a helium gas inflow hole in the conductor disk. Therefore, the area of the conductor disk can be reduced. That is, since the outer diameter of the conductor disk can be made smaller, the outer diameter of the cylindrical body can also be made smaller accordingly. When the outer diameter of the low-temperature terminal is reduced in this way, the inner diameter of the through-hole in the mounting lid through which the low-temperature terminal enters and exits can be reduced, and the area of the flange of the normal-temperature terminal that closes this through-hole is also reduced. Therefore, radiant heat from the room temperature section is reduced, and the amount of liquefied helium consumed in the low temperature container is 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 according to an embodiment of the present invention, and FIG.
3 is a longitudinal sectional view of a superconducting device using the low-temperature terminal portion of a conventional current lead for a superconducting device, FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3, and FIG. is a vertical cross-sectional view of the low-temperature terminal portion in FIG. 3, and FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5. 1-Low temperature container, 2: Superconducting coil, 4: Current lead, 5
: lead body, 7: low temperature terminal part, 9: lead wire, 10 nib spar, 15: cylindrical body, 2o: ring plate, 26: helium gas inflow space, 28: R internal plate. Episode 1, Episode 2, Figure 3, Figure 4

Claims (1)

[Claims] 1) A ring plate installed inside the cryogenic container at the tip of the lead body that supplies power from the outside of the cryogenic container housing the superconducting coil to the superconducting coil inside the cryogenic container, through which the lead body passes, and the mouth of the superconducting coil. In a low-temperature terminal section that is composed of a conductor disk that supports a bus bar that connects outgoing wires, and a cylindrical body into which the conductor disk and the ring plate are respectively fitted into both opening ends, the inner circumferential surface of the cylindrical body A low-temperature terminal portion of a current lead for a superconducting device, characterized in that a helium gas inflow space is formed between the outer peripheral surface of the conductor disk and the outer peripheral surface of the conductor disk.