JPS646524B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a superconducting device,
More specifically, the present invention relates to a superconducting device with a removable current supply lead for a superconducting magnet.

Conventionally, there have been devices of this type as shown in FIGS. 1 and 2. In the figure, current supply lead 1
consists of a pair of positive and negative hollow tubular conductors 2, and a terminal 3 for connecting a cable etc. from an external power supply is connected to the upper end of the conductor 2, and the cryostat 1
It is fixed to an insulating flange 4 that is removably attached to the upper lid body 5 of 1. A cooling gas inlet 6a is provided at the lower part of the conductor 2, and this cooling gas flows out from an outlet 6b at the upper end of the conductor 2. A contact 7 for transmitting current is formed at the lower end of the conductor 2, and the contact 7 fits into a contact socket 8 fixed to an insulating plate 9 to establish an electrical connection. A connecting wire 10 is coupled to the contact socket 8 . A neck tube 12 is formed in the cryostat 11, and a superconducting magnet 14 is immersed in liquid helium 13 stored at the bottom.

With the above configuration, the superconducting magnet 14 housed in the cryostat 11 is cooled to an extremely low temperature by the liquid helium 13 and becomes a superconducting state, and is connected to an external power supply ( (not shown).

Generally, superconducting magnet 14 is operated with a large current of several hundred amperes or more to generate a strong magnetic field. Therefore, in the current supply lead 1, the conductor 2 is made of a material with low electrical resistance, such as copper or aluminum, so as to withstand this large current. In response to the heat generated by the conductor 2 when energized, the evaporated gas of liquid helium 13 is introduced from the inlet 6a to cool the conductor 2.

Furthermore, once the rated current is applied to the superconducting magnet 14, by closing a short circuit switch (not shown) disposed inside the superconducting magnet 14, a circulating current flows inside and the rated current of the superconducting magnet 14 is maintained. , then it becomes possible to disconnect the external power supply. At this time, by disconnecting the external power supply and separating the current supply lead 1 from the cryostat 11, the heat conducted through the conductor 2 is eliminated and the amount of evaporation of the liquid helium 13 is suppressed. That is, by loosening the mounting bolts of the insulating flange 4 so that the insulating flange 4 can be removed from the upper lid 5, and removing the current supply lead 1 upward, the contact 7 and the contact socket 8 are separated. The current supply lead 1 can be removed from the cryostat 11.

Next, when changing the current value of the superconducting magnet 14 or extinguishing it, the current supply lead 1 is inserted again from the top of the cryostat 11, and the contact 7 is completely fitted into the contact socket 8. Must be connected to an external power source afterward.

Here, since the same current flows through the pair of left and right conductors 2, their lengths and diameters are the same, so the contact 7 and the contact socket 8 are spatially on the same level. It is located in

Since the conventional superconducting device is constructed as described above, when the current supply lead 1 that has been detached from the cryostat 11 is reinserted into the cryostat 11, the contact 7 at the tip of the conductor 2 is connected to the lower part of the neck tube 12. It was difficult to fit the contact into the contact receptacle 8 located at. In addition, since it is necessary to maintain electrical insulation between the left and right contact sockets 8, the distance between the contact sockets 8 must be increased, and the distance between the pair of conductors 2 must also be increased. becomes. For this reason, the diameter of the neck tube 12 becomes large, resulting in a drawback that the amount of heat entering the cryostat 11 increases.

This invention was made to eliminate the drawbacks of the conventional devices described above, and provides a superconducting device in which the current supply lead can be easily inserted into the cryostat, and the amount of heat entering the cryostat is reduced. The main purpose is to

Another object of the present invention is to make the cross-sectional areas and lengths of a pair of conductors that constitute the current supply lead different from each other, to facilitate insertion of the current supply lead into the cryostat, and to prevent heat from entering the cryostat. The object of the present invention is to obtain a superconducting device with a reduced amount of intrusion.

The present invention will be described below with reference to an embodiment shown in FIG. In the figure, the current supply lead 1A
The pair of positive and negative conductors 2a and 2b have different lengths, and in order to compensate for the difference in electrical resistance between them, their effective cross-sectional areas are made to be different from each other. The upper ends of the conductors 2a and 2b provided with terminals 3a and 3b, respectively, are fixed to an insulating flange 4 while maintaining the same spatial level, and the insulating flange 4 is removably connected to the upper lid 5 of the cryostat. . As a result, the positions of the contacts 7a and 7b at the lower ends of the conductors 2a and 2b are shifted from each other in the vertical direction. For this reason, the contact socket 8
a, 8b are insulating plates 9a, which are provided as a pair of upper and lower
9b, respectively. The upper insulating plate 9a is provided with a through hole 15 through which the contact 7b of the longer conductor 2b passes.

With the above configuration, when reattaching the detached current supply lead 1A to the cryostat, first insert the contact 7b of the longer conductor 2b into the through hole 15, so that the through hole 15 becomes a guide. Connect the contacts 7a and 7b to the contact socket 8a,
8b, each can be easily fitted and connected. In addition, since the contact sockets 8a and 8b are vertically shifted from each other, electrical insulation between the contact sockets 8a and 8b is facilitated, and the left and right conductors 2a and 2
It is possible to reduce the distance between b and to reduce heat intrusion into the cryostat by making the neck pipe of the cryostat thinner. Furthermore, conductor 2
Since the effective cross-sectional areas of the conductors 2a and 2b are made different so that the electrical resistance values between both ends of the conductors a and 2b are substantially the same, the electrical function is compensated.

As described above, according to the present invention, by providing the current supply lead made of a pair of conductors having different lengths and effective cross-sectional areas, the current supply lead can be reliably and easily inserted into the cryostat.
This has the effect of reducing the amount of heat entering the cryostat.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional current supply lead, FIG. 2 is a longitudinal sectional view of a superconducting device, and FIG. 3 is a longitudinal sectional view of a current supply lead according to an embodiment of the present invention. 1A...Current supply lead, 2a, 2b...Conductor, 3a, 3b...Terminal, 4...Insulating flange,
5... Upper lid, 7a, 7b... Contact, 8a,
8b...Contact socket, 9a, 9b...Insulating plate, 1
1... Cryostat, 12... Neck pipe, 13...
...Liquid helium, 14...Superconducting magnet, 1
5...Through hole of contactor 7b. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A current supply lead that is composed of a pair of positive and negative conductors that are electrically insulated and mechanically coupled to each other and have different lengths and effective cross-sectional areas, and that is detachable from the cryostat. A superconducting device characterized by: 2 The contact formed at the lower end of the conductor is fitted 1
A patent comprising: a pair of insulating plates disposed above and below to which a pair of contact sockets are respectively fixed; and a through hole bored in the upper insulating plate through which the contact of the longer conductor passes. A superconducting device according to claim 1. 3. The superconducting device according to claim 1, wherein the electrical resistance values between both ends of the pair of conductors are substantially the same. 4. Claim 1, wherein the current supply lead is connected to a superconducting magnet immersed in liquid helium housed in a cryostat.
Superconducting device described in Section 1.