JPH05259516A - Normal temperature terminal of current lead for superconducting device - Google Patents

Abstract

PURPOSE:To improve heat exchange rate with a lead wire without lowering flow rate of helium gas by compressing an end of a lead wire bundle held between the halves of a split ring and by inserting it in a lead wire connection hole. CONSTITUTION:A lead wire bundle 12A is compressed and made integral by holding an entire of its end between the halves of a split ring 61, inserted to a lead wire connection hole 16A provided to a connection terminal 17A and is connected to a connection terminal 61 electromechanically. Thereby, clearance between element wires constituting the lead wire bundle 12A can be almost eliminated and each element wire of the lead wire bundle 12A cuts into the split ring 61 and can not be detached, thereby making the lead wire bundle 12A and the split ring 61 integral. Furthermore, it is enough to make a diameter of the lead wire connection hole 16A slightly larger than a diameter of the split ring 61 after compressed, and accordingly, an inner diameter of a tubular body 14A can be reduced. Therefore, it is possible to reduce lowering of flow rate of helium gas 110 and to improve heat exchange effect to cool the lead wire bundle 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature terminal portion which is a room temperature side terminal of a current lead for a superconducting device which supplies electric power to a superconducting coil housed inside a cryogenic container.

[0002]

2. Description of the Related Art Since a superconducting coil uses expensive liquid helium as a refrigerant to hold it in a superconducting state, it is desirable to keep the evaporation amount of this liquid helium small. For this reason, heat intrusion from the current lead to the superconducting coil is required. Needs to be small. FIG. 3 is a cross-sectional view of a conventional cryogenic device using a current lead for a cryogenic device.
The superconducting coil 2 is accommodated in the inside of the container, and the opening is closed by an insulating and heat insulating mounting lid 3.
To keep the superconducting coil 2 at a cryogenic temperature. The actual cryogenic container 1 is housed in a vacuum container having a vacuum space around it to prevent heat from entering from the outside at room temperature by the principle of a thermos bottle. Illustration is omitted.

The lead body 5 of the current lead 4 is provided so as to penetrate the mounting lid 3 in an airtight manner, and a room temperature terminal portion 6 is mounted on the mounting lid 3 at the upper position of the through hole 8 at the upper end outside the cryogenic container 1. The superconducting coil 2 immersed in the liquid helium 100 inside the cryogenic container 1 is connected to the cryogenic terminal portion 7 at the lower end of the lead body 5 via the lead wire 9. FIG. 4 is a cross-sectional view taken along the line AA of the lead body 5 in FIG. 3, in which the wire bundle 12 made of a plurality of strands is closely inserted into the hollow tube 11, and both ends of the wire bundle 12 are at room temperature. It is connected to the terminal portion 6 and the low temperature terminal portion 7. In the lead body 5, the helium gas 110 is circulated between the hollow tube 11 and the conductor wire bundle 12 and in the gap 13 between the wires forming the conductor wire bundle 12 to improve the cooling effect. That is, in FIG. 3, the evaporated helium gas 110 enters the inside of the lead body 5 from the low temperature terminal portion 7 of the current lead 4 through a through hole (not shown), flows through the gap 13 in the lead body 5, and the conductor wire bundle 12
As shown in FIG.
Is discharged into the atmosphere from the outlet pipe 15 at or is guided to the compressor. The cooling with the helium gas 110 has a function of removing Joule heat generation in the wire bundle 12 and conduction heat from the room temperature portion. With this function, the wire bundle 1
The amount of heat penetrating from 2 to the superconducting coil 2 which is maintained at an extremely low temperature is reduced.

FIG. 5 is a sectional view of a conventional room temperature terminal portion 6, FIG.
FIG. 6 is a view on arrow P of FIG. The room temperature terminal portion 6 comprises a helium gas container 20 and a conductor wire bundle 12 passing through the container.
The helium gas container 20 has a cylindrical body 14 having an outlet pipe 15 on a side wall surface thereof, a connecting terminal 17 having a connecting plate 171 for connecting two conducting wire connecting holes 16 and external leads, and a mounting flange 19 having a conducting wire through hole 18. And the lead wire bundle 12 introduced from the lead body 5 through the lead wire through hole 18 into the connection terminal 1 through the lead wire connection hole 16.
7 is electrically connected. The mounting flange 19 is mounted on the upper end of the hollow tube 11 of the lead body 5 and is hermetically mounted on the mounting lid 3 via the O-ring 21 at a position where the conductor through hole 18 and the hollow tube 11 are concentric. ..

The lead wire bundle 12 that protrudes from the upper end surface of the hollow tube 11 of the lead body 5 and penetrates the lead wire through hole 18 and is introduced into the helium gas container 20 is divided into two inside the cylindrical body 14. It The two wire bundles 12 are inserted into the two wire connection holes 16 one by one, and the upper surface portion thereof is TIG-welded to be electrically and mechanically connected to the connection terminals 17. TIG welding is a method of generating an arc between a non-consumable electrode and an object to be welded under an inert gas atmosphere and locally melting the non-welding object by the heat to perform welding, which is often used for copper welding. This is the welding method used.

The conductor bundle 12 is divided into a plurality of pieces in order to increase the surface area of the conductor bundle 12 in the helium gas container 20 and improve the cooling effect of the helium gas 110. Although these figures show an example of dividing into two, it is also possible to divide into three. In such a case, the arrangement of the plurality of conductor connection holes 16 and the connection plate 171 is different from that in FIG. 6, but the connection plate 171 does not have to be provided in the center of the connection terminal 17 as shown in FIG. Alternatively, the configuration is not limited to the configuration of standing vertically upward as shown in FIG. 5, and the configuration of horizontally projecting the connection plate 171 to the left or right of FIG. 5 can be adopted as will be described later. The position of the connecting plate 171 is not restricted when the plurality of conductor connecting holes 16 are arranged in the connecting terminal 17.

The conductor wire bundle 12 is connected to the connection terminal 17 by TIG welding as described above. Generally, the conductor wire bundle 1 made of copper is used.
It is also possible to braze silver brazing or the like to attach 2 to the connection terminal 17 also made of copper. However, in consideration of the temperature rise of the wire bundle 12 in consideration of the case where the supply of helium gas for cooling is interrupted for some reason, the use of silver braze having a relatively low melting point is avoided and the respective materials are directly welded to each other. TIG welding is used.

[0008]

If the room temperature terminal portion 6 is constructed as described above, the rated current is as large as several tens of KA, and the number of wires of the conductor wire bundle 12 is increased accordingly, for example, several hundreds. When it becomes a certain degree, the work of dividing the conductor wire bundle 12 into a plurality of conductor wire bundles 12 while expanding in the helium gas container 20 in the radial direction and inserting each conductor wire bundle 12 into the conductor wire connection hole 16 is performed. The working method in which the tip of the wire bundle 12 is fixed in advance with silver brazing and then inserted into the wire connecting hole 16 cannot be adopted for the above-mentioned reason. Therefore, insert the wire into the wire connecting hole 16 in a separated state. Inevitably, therefore, it is necessary to manufacture the conductor connecting hole 16 with a large diameter in order to insert all the wires. In addition, in such wire insertion work, the wire that has not been inserted is the cylindrical body 1.
Since it is held in a curved state in 4, the inner diameter of the cylindrical body 14 must be increased so as to have a space available for it.

As described above, since the inner diameter of the cylindrical body 14 is increased for two reasons, the helium gas 11 in the cylindrical body 14 is increased.
There is a problem that the cross-sectional area in which 0 flows increases, the flow velocity decreases, and the cooling effect decreases. Therefore, there is a problem that increasing the number of divided wires of the conductor wire bundle 12 in order to improve the cooling effect has the opposite effect and the desired cooling effect cannot be obtained.

An object of the present invention is to solve such a problem and to provide a room temperature terminal portion of a current lead for a superconducting device in which the flow rate of helium gas does not decrease so much and the efficiency of heat exchange with a conductive wire is high.

[0011]

In order to solve the above-mentioned problems, according to the present invention, a cylindrical body, a mounting flange to be mounted on a mounting lid of the cylindrical cryogenic container, and an external lead mounted on the upper portion of the cylindrical body are provided. Inside the helium gas container consisting of connection terminals to be connected, at room temperature terminal portion of the current lead for superconducting device, which is connected to the connection terminal by introducing a conductor wire bundle from the lead body through the through hole of the mounting flange. The tip of the bundle of conductors to be connected to the connection terminal is sandwiched by two split rings and crimped, and this is inserted and fixed in a conductor connection hole provided in the connection terminal. Is covered with a connection hole lid, and the bundle of conductors introduced from the lead body into the helium gas container is collected into one and sandwiched by two split rings to be crimped to form one conductor connection hole. Insert the lead wire into the helium gas container from the lead body and divide it into a plurality of bundles. According to the number, the plurality of conductor wire connection holes provided in the connection terminals are respectively inserted and fixed.

[0012]

In the structure of the present invention, the leading end of the bundle of conductors introduced from the lead body into the helium gas container is sandwiched by the two-divided rings and crimped, so that the leading end is integrated so that it is provided at the connection terminal. The work of inserting it into the conductor connection hole and fixing it by TIG welding etc. becomes easy, and the diameter of the tip part becomes smaller due to crimping, and the outer diameter of the split ring after crimping is accurately determined by the size of the crimping fitting of the crimping device Since it is easy to insert into the conductor wire connection hole, it is not necessary to increase the diameter with a margin and it may be small.Therefore, the area of the connection terminal where the conductor wire connection hole is provided becomes smaller and the same number of conductor bundles can be obtained. On the other hand, as a result, the diameter of the cylindrical body can be reduced as compared with the conventional one. Also, in the case of a configuration in which the helium gas container is guided from the outlet pipe 15 to the compressor and is again made into liquid helium and recovered, a connection hole lid is airtightly attached to the upper part of the conductor connection hole and the tip end of the conductor bundle is externally connected. By preventing the helium gas from leaking, it is not necessary to take a gas leak preventing measure in the work of fixing the tip of the conductor bundle.

Further, in the structure in which all the conductor wire bundles are connected to the connection terminals, the surface area of the conductor wire bundles is reduced, but the diameter of the cylindrical body can be minimized, so that the cooling effect due to the increase in the flow velocity of the helium gas is improved. Improvement can be expected.
In the case of a structure in which a plurality of conductor bundles are divided and crimped by two-divided rings and inserted and fixed in the same number of conductor connecting holes, the diameter of the cylindrical body is larger than that in the case of one conductor bundle. Since the surface area of the is increased, the improvement of the cooling effect can be expected.

[0014]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a plan view of a room temperature terminal portion 6A showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line BB of FIG. 1, and the same members as those in FIGS. For members having functions, a subscript A is attached and detailed description is omitted. In these drawings, the conductor wire bundle 12A is collectively bundled at its tip end with a split ring 61 and crimped by a predetermined crimping device to integrate the tip end face into a conductor wire connection hole 16A provided in a connection terminal 17A. After insertion, the upper end surface of FIG. 2 is fixed by TIG welding to electrically and mechanically connect to the connection terminal 61.

Since the conductor bundle 12A is sandwiched between the two-divided rings 61 and compressed with a strong force to be crimped, there is almost no gap between the wires forming the conductor bundle 12A, and the two-divided ring 61 has the conductor bundle 12A The individual wires bite into each other and do not separate, so that the conductor bundle 12A and the double ring 61 are integrated. Since this is inserted into the conductor wire connecting hole 16A, the diameter of the conductor wire connecting hole 16A can be made slightly larger than the diameter of the double ring 61 after crimping, and can be made smaller than in the conventional case. The inner diameter can also be reduced,
The decrease in the flow velocity of the helium gas 110 is reduced, and as a result, the heat exchange effect of cooling the conductor bundle 12A by the helium gas 110 is improved.

Since the conductor bundle 12A is one, the surface area is smaller than that in FIG. 5, which is a factor that deteriorates the cooling effect in this respect, but the cooling effect is improved by increasing the flow velocity of the helium gas 110. If the value is large, the number of conductor bundles 12A may be one as shown in FIG. If cooling is improved by dividing the conductor bundle 12A to increase the surface area, the conductor bundle 12A is divided into a plurality of conductor bundles, and the tip portions of the conductor bundles 12A are individually sandwiched by two-divided rings and crimped to form a plurality of conductor wire connection holes. 16A
It adopts the configuration of inserting and fixing in each. In this case, in order to provide a plurality of conductor connection holes 16A, connection terminals 17A are provided.
Becomes larger, the inner diameter of the cylindrical body 14A also increases accordingly, and the flow velocity of the helium gas 110 decreases.
It suffices if the overall cooling effect is improved. As described above, since the tip end portion of the conductor bundle 12A is compressed and integrated by the two-divided ring 61, the diameter of the conductor wire connection hole 16A is smaller than that of the conventional structure even if the number of conductor wire bundles 12A is the same. Since the inner diameter of can be made smaller, the cooling effect is still improved. As described above, the cooling effect of the wire bundle 12A is related to the two contradictory matters of the flow rate of helium gas and the number of divisions. Therefore, the current rated value of the current lead (4) and the wire bundle 12A determined by the current rating value The optimum number of divisions of the wire bundle 12A and the like are determined by comprehensively considering factors such as the number of strands and the generation amount of the helium gas 110 related to the size of the superconducting device.

[0017]

As described above, according to the present invention, since the tip portion of the conductor wire bundle is sandwiched by the split ring and crimped, the tip portion is integrated with the split ring. The effect of facilitating the work of inserting it into the cable and fixing it by TIG welding etc. is obtained, and the diameter of the tip part is reduced by crimping, and the outer diameter of the split ring after crimping is accurate depending on the size of the crimping fitting of the crimping device. Since the diameter of the conductor wire connection hole can also be made smaller, the area for providing the conductor wire connection hole can be made smaller, and the diameter of the cylindrical body can be consequently made smaller than the conventional case for the same conductor bundle. The effect of increasing the flow rate of helium gas in the cylindrical body and improving the cooling efficiency can be obtained.

Further, in the case of an apparatus in which the helium gas discharged from the outlet pipe 15 of the helium gas container is guided to a compressor to be liquefied and returned to the cryogenic container to reduce the helium consumption, a lead wire connection hole is provided. If the connection hole lid is airtight at the top of the to prevent helium gas from leaking from the tip of the conductor bundle to the outside, it is not necessary to secure airtightness when fixing the tip of the conductor bundle by TIG welding or the like. The effect that the work becomes easy is obtained.

Further, in the structure in which the conductor wire bundles are all integrated into one and are integrated by the two-divided ring and connected to the connection terminal, the surface area of the conductor wire bundle is small, but the diameter of the cylindrical body can be minimized, so that the flow velocity of helium gas is large. It can be expected to improve the cooling effect. Further, in the case of a structure in which the conductor bundle is divided and inserted and fixed in the same number of conductor connection holes, the diameter of the cylindrical body is larger than that of a single conductor bundle, but the surface area of the conductor bundle is larger and the cooling effect is improved. Can be expected to improve. In this case, by adopting a configuration of crimping using a two-divided ring, the diameter of the lead wire connection hole is reduced, and as a result, the flow rate of helium gas in the helium gas container is increased,
There is no doubt that the cooling effect will be improved compared to the past.

[Brief description of drawings]

FIG. 1 is a sectional view of a room temperature terminal portion showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a sectional view of a superconducting device using current leads.

4 is a sectional view taken along line AA of FIG.

FIG. 5 is a sectional view showing a room temperature terminal portion of a conventional current lead.

FIG. 6 is a view on arrow P of FIG.

[Explanation of symbols]

 1 Low Temperature Container 2 Superconducting Coil 3 Mounting Lid 4 Current Lead 5 Lead Body 6 Room Temperature Terminal 6A Room Temperature Terminal 7 Low Temperature Terminal 12 Conductor Bundle 12A Conductor Bundle 14 Cylindrical Body 14A Cylindrical Body 15 Outlet Tube 15A Outlet Tube 16 Conductor Connection Hole 16A Conductor connection hole 17 Connection terminal 17A Connection terminal 61 Divided ring 64 Connection hole lid 20 Helium gas container 20A Helium gas container

Claims (4)

[Claims] 1. A cylindrical body (14A), the cylindrical body (14A)
A helium gas container (20) comprising a mounting flange (19A) for mounting the battery on the mounting lid (3) of the cryogenic container (1) and a connection terminal (17A) mounted on the upper part of the cylindrical body (14A) and connected to an external lead. A lead wire bundle (12A) is introduced from the lead body (5) through the through hole of the mounting flange (19A) into the inside of the connection terminal (17).
In the room temperature terminal part of the current lead (4) for the superconducting device connected to A), the tip of the wire bundle (12A) connected to the connection terminal (17A) is divided into two split rings (6).
A room temperature terminal portion of a current lead for a superconducting device, characterized in that it is sandwiched by 1) and crimped, and this is inserted and fixed in a conductor connection hole (16A) provided in the connection terminal (17A). 2. The conductor connecting hole (16A) is provided with a connecting hole lid (64).
The room temperature terminal part of the current lead for a superconducting device according to claim 1, wherein the room temperature terminal part is airtightly covered with. 3. A conductive wire bundle (12A) introduced from a lead body (5) into a helium gas container (20) is put together into one and sandwiched by two split rings (61) and crimped to form one conductive wire connecting hole. The room temperature terminal portion of the current lead for a superconducting device according to claim 1 or 2, wherein the room temperature terminal portion is inserted in (16A) and fixed. 4. A conductor wire bundle (12A) introduced from a lead body (5) into a helium gas container (20) is divided into a plurality of bundles, and each tip portion thereof is divided into two separate rings (61).
2. A plurality of conductor wire connection holes (16A) provided in the connection terminals (17A) according to the number of conductor wire bundles (12A) are inserted and fixed by sandwiching each of them and crimping. The room temperature terminal portion of the current lead for a superconducting device according to 2.