JPH0817620A - Current lead of superconducting equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] High cooling efficiency in the device that cools the current lead by guiding the cooling gas to the current lead of the superconducting equipment.
To provide a thermally stable current lead for a superconducting device. [Constitution] Particles (1
4) is filled and, for example, the particles (14) are fluidized to form a fluidized bed to cool the current leads.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to current leads for superconducting equipment.

[0002]

2. Description of the Related Art Currently, alloy superconducting materials are generally used as superconducting materials. In order to maintain the superconducting state of the superconducting material, it is necessary to put the superconducting device made of the superconducting material in the cryostat and maintain the helium temperature. For this reason,
A current lead connecting the terminal on the room temperature side and the superconducting device at the helium temperature is required. In addition to heat input from the outside, the current lead also generates heat from the current lead itself, and a heat exchange type is usually used to remove this heat. The heat exchange type current lead is composed of normal conducting metal or superconducting metal, takes the surface area as large as possible, and exchanges heat with the helium gas evaporated from the helium reservoir placed under the current lead to cool it. I do. FIG. 4 shows a configuration example of a superconducting magnet and a current lead as an example of a superconducting device. The current that excites the superconducting magnet 1 is
It flows from a room temperature power source 2 to a cryogenic superconducting magnet 1 in a cryostat 4 via a room temperature conductor 3. The current terminal 6 at the room temperature above the cryostat 4 to the cryogenic current terminal 7 on the side of the superconducting magnet 1 is called a current lead 5. FIG. 5 shows a configuration example of the current lead 5. Current lead 5
Is a cooling gas 10 consisting of helium gas from the helium reservoir 9
Is taken in and heat is exchanged between the cooling gas 10 and the current lead energization section 8. When designing the current leads, consider the energizing current, the outer dimensions of the current leads, the heat loss of the cryostat, etc. For example, in the design of a current lead made of a normal-conducting metal, if the cross-sectional area of the current lead is reduced in order to reduce heat intrusion from the room temperature portion, the electric resistance of the current lead itself increases and Joule heat generation increases. On the contrary, if the cross-sectional area of the current lead is increased, heat input from the outside due to heat conduction increases. Therefore, it is necessary to design the heat considering the balance of the heat input from the outside, the heat generation of the current leads, the cooling effect of the cooling gas, etc. Has been done.

[0003]

By the way, in recent years, the size of superconducting devices has been increasing, and the current lead required has a tendency to increase in current. Along with this, heat intrusion from the outside and Joule heat generation of the current leads also increase. Also,
In the current lead used in the superconducting device for alternating current, if the current lead is made of a superconducting metal, heat generation due to AC loss becomes large and it becomes thermally unstable. Therefore, an object of the present invention is to provide a thermally stable current lead of a superconducting device with high cooling efficiency.

[0004]

In order to achieve the above object, the current lead of the superconducting device according to the present invention is characterized in that the cooling gas passage of the current lead is filled with particles.

[0005]

According to the present invention, the flow of the cooling gas is disturbed by filling the cooling gas flow path of the current lead with particles, and the contact heat conduction between the particles and the current lead is added, whereby The heat exchange between the cooling gases is promoted and the current leads can be made thermally stable.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the current lead of a superconducting device of the present invention will be described below with reference to FIGS. 1, 2 and 3. 1, 2, and 3, the same parts as those in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted. 1 and 2 is different from FIG. 5 in that the cooling gas passage 12 has a dispersion plate 13
And the particles 14 are filled in the cooling gas channel 12. FIG. 1 shows a cooling gas flow path on the outer periphery of the current lead conducting portion 8.
FIG. 2 shows a configuration example in which 12 is provided, and FIG.
This is an example of a configuration in which a cooling gas channel 12 is provided inside. FIG. 3 shows the current lead conducting part 8 and the cooling gas 10 when the particles are filled,
3 is a diagram showing a heat transfer mechanism between particles 14. FIG. If the particles 14 are not filled as in the conventional case, the cooling of the current lead is
There is only heat transfer between the cooling gas 10 and the current lead energization portion 8. However, by filling the particles 14 with the cooling gas 10
The flow of electricity is disturbed, and the current lead conducting part 8 and particles
The cooling effect of the current leads is promoted by the addition of contact heat conduction between them.

For example, minute particles having a small specific gravity such as plastic or alumina particles are used as the packing particles, and the packing is performed by considering the flow path cross-sectional area, the pressure loss of the dispersion plate, the packing amount of the particles, and the cooling gas flow rate. A fluidized bed is formed by the particles and the cooling gas. At this time, the fluidized particles disturb the temperature boundary layer in the vicinity of the current leads, which can be expected to dramatically improve the cooling effect of the current leads.

Further, as shown in FIG. 2, it is expected that the cooling gas flow paths will be duplicated and the pressure loss of each flow path will be investigated by the dispersion plate 13 to distribute the cooling gas flow rate to an appropriate ratio.

[0009]

According to the present invention, the cooling gas flow path of the current lead is filled with particles to disturb the flow of the cooling gas, and the heat transfer effect is promoted by the contact heat conduction between the particles and the current lead. , The current leads are thermally stable.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a current lead of a superconducting device of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a current lead of a superconducting device of the present invention.

FIG. 3 is a diagram showing a heat transfer mechanism of a current lead of the superconducting device of the present invention.

FIG. 4 is a configuration diagram showing an example of a conventional superconducting device.

FIG. 5 is a configuration diagram showing an example of a current lead of a conventional superconducting device.

[Explanation of symbols]

1 ... Superconducting coil, 2 ... Power supply, 3 ... Room temperature conductor, 4 ... Cryostat, 5 ... Current lead, 6 ... Room temperature current terminal, 7
... cryogenic current terminal, 8 ... current lead conducting part, 9 ... helium reservoir, 10 ... cooling gas, 11 ... liquid helium, 12 ... cooling gas passage, 13 ... dispersion plate, 14 ... particles, 15 ... contact heat conduction.

Claims (5)

[Claims] 1. A current lead for a superconducting device in which a cooling gas is introduced into a current lead for the superconducting device to cool the current lead, wherein the cooling gas passage is filled with particles. 2. An apparatus for inserting one end of a current lead into an upper space in a cryostat to guide cooling gas in the cryostat to the current lead and cooling the current lead, and providing a dispersion plate at an end of the cooling gas flow path. A current lead for a superconducting device, characterized in that the cooling gas channel is filled with particles. 3. A cooling gas passage is provided on the outer periphery of the current lead,
The current lead of the superconducting device according to claim 1 or 2, wherein the cooling gas channel is filled with particles. 4. A cooling gas passage is provided inside the current lead,
The current lead of the superconducting device according to claim 1 or 2, wherein the cooling gas channel is filled with particles. 5. The current lead of a superconducting device according to claim 3, wherein the particles are fluidized by a cooling gas to cool the current lead as a fluidized bed.