JPH0512874B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention is applicable to poles that require high strength and high cooling performance, such as the current leads of the rotor of a superconducting rotating electric machine, and which supply current from a normal temperature part to a low temperature part. Regarding current leads for low temperature equipment.

[Technical background of the invention and its problems] Conventionally, when a large current is supplied from a normal temperature part to a low temperature part, especially in the liquid helium temperature range, it is necessary to prevent conductive heat from the normal temperature part and Joule heat due to the current from entering the low temperature part. To achieve this, current leads are cooled with helium vapor or the like. In this early version, the outer circumference of the cylindrical current lead was simply cooled with helium vapor, but the cooling performance was not very good, so a type that installed a heat exchanger inside the current lead was used. However, various proposals have been made. The heat exchanger in this current lead is often constructed by arranging a large number of cooling fins or using a mesh-like electrical conductor. Therefore, such current leads can provide good performance when used in stationary cryogenic equipment, but when a strong centrifugal force is applied, such as the current lead for the rotor of a superconducting rotating electric machine, mechanical The drawback was that it was not strong enough.

[Object of the Invention] An object of the present invention is to provide a current lead for a cryogenic device that is mechanically strong and has good cooling performance.

[Summary of the Invention] The current lead for cryogenic equipment of the present invention is made by twisting a large number of pipes made of conductive metal and inserting them into an outer cylinder made of conductive metal, so that the current lead is formed by the pipes and the outer cylinder. The void inside the outer cylinder is densely filled with a filling member made of conductive metal, the pipe, the outer cylinder, and the filling member are integrated, and the inside of the pipe is used as a refrigerant passage.
It is characterized by connecting a normal temperature side terminal and a low temperature side terminal to both ends of the outer cylinder, and providing an insulating coating around the outer periphery of the outer cylinder.The inside of the outer cylinder is densely packed with pipes and filling materials, which makes it easier for the machine to operate. By increasing the mechanical strength and using the interior of the many twisted pipes as a refrigerant flow path, the flow of the refrigerant becomes a swirling flow, improving cooling performance.

[Embodiments of the Invention] Examples of the present invention will be described below with reference to FIGS. 1 and 2.

A large number of pipes 1 (47 in Fig. 2) made of conductive metal and having a circular cross-section are plated with solder (silver solder may also be used) and tightly twisted together to form a cylindrical outer shape made of conductive metal. It is inserted into the cylinder 2, and the conductive metal dissolved in the gap inside the outer cylinder 2 is poured into the gap inside the outer cylinder 2. At this time, the inner periphery of the outer cylinder 2 is plated with solder (silver solder may also be used). By doing this, the solder-plated parts on the inner periphery of the pipe 1 and the outer cylinder 2 are melted, and then by cooling, the pipe 1, the outer cylinder 2, and the filling member 3 are integrated, resulting in good electrical and thermal conduction and mechanical stability. becomes stronger. The inside of the pipe is a refrigerant passage 4, and a normal temperature side terminal 5 and a low temperature side terminal 6 are connected to both ends of the outer cylinder 2. An insulating coating 7 is provided on the outer periphery of the outer cylinder 2.

Next, the effect will be explained.

Current flows through the pipe 1, the outer cylinder 2, and the filling part 3.
Therefore, Joule heat is generated in this part, and the heat conducted from the normal temperature side terminal 5, which is the normal temperature part, to the low temperature side terminal 6, which is the low temperature part, is also conducted through the pipe 1, the outer cylinder 2, and the filling member 3. In order to prevent this heat from entering the low-temperature part, a refrigerant such as helium gas is passed through the refrigerant passage 4 of the pipe 1 to remove heat from the inner surface of the pipe 1. This heat exchange effect is due to the fact that the flow of refrigerant in the current lead is a swirling flow, so it is possible to obtain performance equivalent to or better than the conventional example that uses many fins. Even if twisting occurs, since the pipes 1 are twisted together, there is no deviation in the temperature distribution of the current leads, which has the advantage of keeping heat intrusion low. Also,
Since the pipe 1 is closely integrated with the outer cylinder 2 and the filling member 3, heat from the outer cylinder 2 and the filling member 3 is also efficiently removed. Note that the shape of the cooling passage 4 of the pipe 1 does not have to be the same as the circular outer shape of the pipe 1; it may be square, for example, or may have an uneven inner surface to further enhance the cooling effect.

In addition to the cooling effect as described above, the current lead of this embodiment is mechanically very strong because a large number of pipes 1 and the filling member 3 are densely packed and integrated into the outer cylinder 2. Therefore, it is suitable for current leads placed in a high centrifugal force field, such as current leads for the rotor of a superconducting rotating electrical machine, or for current leads that are subject to large mechanical forces.

In addition to the embodiments described above and shown in FIGS. 1 and 2, the pipe 1 may have a square cross-sectional shape as shown in FIG. 3, or a hexagonal shape as shown in FIG. You can also do it. This improves the space factor of the pipe.

Note that the shapes of the pipe 1, outer cylinder 2, etc. may be other shapes than those in the above embodiments.

[Effects of the Invention] As explained above, according to the present invention, a large number of pipes made of conductive metal are twisted together,
These are inserted into an outer cylinder made of conductive metal, and the gaps within the outer cylinder are densely filled with a conductive filling member, making it extremely strong mechanically. Furthermore, the inside of the pipe is used as a refrigerant passage, and by twisting the pipe, the refrigerant forms a swirling flow, making it possible to provide a current lead for a cryogenic device with good cooling performance.

[Brief explanation of the drawing]

FIG. 1 is a cutaway elevational view of essential parts showing the first embodiment of the current lead for cryogenic equipment of the present invention, and FIG.
FIGS. 3 and 4 are enlarged cross-sectional views taken along the - line in the figure, and are cross-sectional views showing second and third embodiments. 1...Pipe, 2...Outer cylinder, 3...Filling member,
4... Refrigerant passage, 5... Normal temperature side terminal, 6... Low temperature side terminal.

Claims (1)

[Claims] 1. In a current lead for a cryogenic device that supplies current from a room-temperature part to a low-temperature part, a number of pipes made of conductive metal are twisted together, and these are placed inside an outer cylinder made of conductive metal. The pipe, the outer cylinder, and the filling member are integrated by inserting the pipe into the outer cylinder, and the gap in the outer cylinder formed by the pipe and the outer cylinder is densely filled with a filling member made of conductive metal. Connect the normal temperature side terminal and the low temperature side terminal to both ends of the
A current lead for cryogenic equipment characterized by an insulating coating provided on the outer periphery of the outer cylinder. 2. Claim 1, wherein the pipe has a regular hexagonal or quadrangular cross-sectional outer shape.
Current leads for cryogenic equipment as described in section. 3. A current lead for a cryogenic device according to claim 1 or 2, wherein the current lead is disposed within a rotor of a rotating electric machine.