CN1084313A

CN1084313A - Superconductive current lead

Info

Publication number: CN1084313A
Application number: CN93103129A
Authority: CN
Inventors: 笹冈高明
Original assignee: Hitachi Cable Ltd
Current assignee: Hitachi Cable Ltd
Priority date: 1992-09-14
Filing date: 1993-03-15
Publication date: 1994-03-23
Anticipated expiration: 2013-03-15
Also published as: KR100275091B1; CA2091595A1; EP0588461B1; DE69310649D1; CN1044941C; DE69310649T2; EP0588461A1; KR940007902A

Abstract

The material that thermal conductivity is low when being lower than room temperature is as the basic building block that constitutes superconductive current lead.Basic building block and oxide system superconduction member combine.Basic building block makes the heat minimizing of passing to special low temperature side from superconductive current lead.

Description

Superconductive current lead

The present invention relates to a kind of superconductive current lead, more particularly, relate to the improvement that a kind of superconductive current lead is done, the superconducting apparatus that this superconductive current lead system will be placed in special low-temperature environment is connected to the superconductive current lead of the power supply that is placed in room temperature environment etc.

Its cross section system of current feed that uses for superconducting apparatus designs to such an extent that make the heat that electric current produced of the current feed of flowing through and its summation of heat that passes to current feed from high-temperature part reach minimum degree, and the evaporation capacity that resembles the cooling agent of helium and so on also reaches minimum degree.

In the ordinary course of things, current feed is made of copper cash.In this case, the someone studied and adopts each oxide system superconducting metal line with silver coating to achieve the above object.

But the current feed that is made of silver layer oxide system superconducting metal line has the big shortcoming of heat output, this is because the thermal conductivity of silver cause higher than other metal under the special low-temperature space of superconducting apparatus operation temperature area, although this has such benefit, promptly the stability of superconducting metal wire has improved.

This current feed also has such shortcoming and since alternating current or transient current when flowing through current feed the resistance of silver layer under special low temperature, become very low, thereby the Joule heat that silver layer eddy current and couple current are produced can not be ignored.

Therefore, the purpose of this invention is to provide a kind of superconductive current lead, the heat that passes to this superconductive current lead from outside high-temperature part reduces to some extent.

The superconductive current lead that the Joule heat that another object of the present invention provides a kind of electric current to produce reduces to some extent.

The present invention also has another purpose, and a kind of like this superconductive current lead promptly is provided, and adopts this lead-in wire can reduce the evaporation capacity of cooling agent.

Superconductive current lead of the present invention comprises:

The superconducting metal line of predetermined quantity, each superconducting metal line comprises:

First member that the oxide system superconductor constitutes; With

Second member that representative constitutes at the predetermined thermal conductivity material that is lower than under the room temperature, this predetermined thermal conductivity is less than the thermal conductivity under the room temperature.

The thermal conductivity that reduces a kind of material must reduce the resistance of this material, thereby eddy current loss or couple current loss reduce when making alternating current or transient current flow through superconductive current lead.

Oxide system superconductor among the present invention can be from for example Y-Ba-Cu-O, Bi-Sr-Cu-O, Bi-Pb-Sr-Ca-Cu-O, Tl-Ba-Cu-O, Tl-Ba-Ca-Cu-O, Tl-Sr-Cs-Cu-O, La-Sr-Cu-O, the material that La-Ba-Cu-O chooses, and can be to be selected from for example to contain main component Au or Ag and at least a element Pd being lower than the material that thermal conductivity is little under the temperature of room temperature (being equivalent to high-resistance material), Pt, Mn, Mg, the alloy of Ar or Au, contain filtering metal system alloy as the material (this main component becomes oxide in the superconductor heat treatment process) of main component with such as aluminium oxide, MgO, the oxide system material of LaAlO and so on.

The a little materials of those of rank rear can be as the enhancing ingredients of superconductive current lead, simultaneously can oxide system lead material with than low thermal conductivity material between insert the noble metal composition the barrier layer.

When enhancing ingredients adopted the Ag-Au alloy, the content of Au should be preferably 1 to 10% less than 15% with atomic ratio measuring.

The superconducting metal wire of predetermined quantity can be one or more superconducting metal wire.

Illustrate in greater detail content of the present invention now in conjunction with the accompanying drawings.In the accompanying drawing:

Fig. 1 is the schematic diagram that superconducting apparatus is connected to the superconductive current lead of power supply;

Fig. 2 is the perspective view of the superconductive current lead of the present invention's first most preferred embodiment;

Fig. 3 is the perspective view of the superconductive current lead of the present invention's second most preferred embodiment;

As seen from Figure 1, superconductive current lead 4 is connected on superconducting coil (equipment) 3 and the current feed 5 by connector 41 and 42, power supply 6 is added to superconducting coil 3 two ends with predetermined voltage through current feed 5 and superconductive current lead 4, and wherein superconducting coil 3 and superconductive current lead 4 are immersed in the liquid helium 2 that is contained in container 1.

Fig. 2 shows the superconductive current lead 4 that most preferred embodiment of the present invention is used for equipment shown in Figure 1.Superconductive current lead 4 is made up of a plurality of strip metal lines 7, and each strip metal line 7 all is made of heart yearn 8 and the alloy cladding layer 9 that an oxide system superconductor is made.

In the first real side of first most preferred embodiment, heart yearn 8 is 1223 mutually the oxide system superconductors (Tl-Pb-Sr-Ba-Ca-Cu-O) that contain as the T1 of main component and Pb single-layer system, alloy cladding layer 9 is Au-5 atom %Pb alloys, wherein each superconduction bandwidth is 2.4 millimeters, thick 1.4 millimeters, 3.3 square millimeters of sectional areas.The superconductive current lead of so making 4 is immersed in the liquid helium that temperature is 77K, about 100 peaces of its superconduction critical electric current.The electric current lead-in wire 4 and 5 o'clock of flowing through estimates that according to the evaporation capacity of liquid helium 2 the heat side definite value that passes to liquid helium 2 when whenever having 1 peace electric current to flow through is about 0.05 milliwatt.From this result, can affirm that this superconductive current lead 4 has the very little characteristic of heat transfer.This is because due to alloy cladding layer 9 structures that thermal conductivity is low under employing low temperature.Thereby reduced and passed through the heat that alloy cladding layer 9 is transmitted.

When the alternating current of 60 He Zhi passed through superconductive current lead 4, after measured, when whenever having 1 peace electric current to flow through, the heat of nearly 1 milliwatt passed in the liquid helium 2.This result superconduct lead-in wire 4 certainly is very little conductors of thermal losses.This be since the resistance of alloy cladding layer 9 big due to, thereby the eddy current that has reduced conductor decreases the loss of not sum couple current.

In second example of first most preferred embodiment, the size of superconductive current lead 4 is identical with first example, but the alloy cladding layer 9 that heart yearn of being made by the oxide system superconductor (Bi-Sr-Ca-Cu-O) of Bi12212 system 8 and Ag-3 atom %Au alloy are made constitutes.

These superconductive current lead 4 its critical currents that are immersed in temperature and are in the liquid helium 2 of 4.2K are 10 peace/square centimeters, and this value that obtains when adopting fine silver with clad material is identical.The resistivity that draws simultaneously is up to 0.7 to 1.2 micro-ohm centimetre, shows and adopts fine silver to compare as the situation of clad material under very low temperature region to alter a great deal.

Relevant with the resistivity of alloy cladding layer 9, the thermal conductivity of the superconductive current lead 4 common current lead-in wire of making than phosphorus one deoxidized cooper that becomes is little.Therefore, adopt the situation of pure Ag with coating layer and compare, this superconductive current lead 4 is available, and its eddy current loss is 1%

As for the resistance of connector 42 and 41, its resistance not only descends, but also As time goes on settles out.

Listed the thermal conductivity (watt/meter K) of alloy cladding layer under different temperatures in first and second examples of most preferred embodiment in the following table.

Temperature (K) the first example second example fine silver

260 500 160 590

77 170 51 530

20 75 10 25,000

Fig. 3 shows the superconductive current lead of the present invention's second most preferred embodiment.This superconductive current lead comprises the basic building block 10 that aluminium oxide makes, thin layer 11 and the oxide system superconducting layer 12 that silver is made.The basic member 10 of aluminium oxide can replace with Ag-Au alloy basic building block.

That as above spoke face to face is such, basic building block of the present invention adopts and is being lower than the material that thermal conductivity descends under the temperature of room temperature, thereby the heat minimizing of not only passing to cooling agent by basic building block, and lead-in wire also reduces because of electric current flows through the heat that produces, thereby reduced the consumption and the load of refrigerator cooling agent.

Though for knowing that intactly disclosing content of the present invention only describes with regard to some specific embodiments, but therefore this specification appending claims is not restricted, embodied all modifications scheme and other structures that those skilled in the art that can propose and should look it, and all these should belong in the nature of things in the scope of the basic instruction that this specification proposes.

Claims

1, a kind of superconductive current lead comprises:

The superconducting metal line of predetermined quantity, each superconducting metal line comprises;

First member that the oxide system superconductor constitutes; With

At second member that is lower than the material of predetermined thermal conductivity under the room temperature, this predetermined thermal conductivity is less than the thermal conductivity under the room temperature.

2, superconductive current lead according to claim 1 is characterized in that:

Described second member is a kind of alloy, and this alloy is a main component with Au or Ag, and contains at least one element among Pd, Pt, Mn, Zt and the Au.

3, superconductive current lead according to claim 1 is characterized in that:

Described first member is coated with described second member, forms described superconducting metal wire thus; And

The described superconducting metal wire of described predetermined quantity is piled up configuration.

4, superconductive current lead according to claim 1 is characterized in that:

Described first components layer is stacked on the surface of described second member, forms described superconducting metal wire;

Lead wire and pile up configuration for described of described predetermined quantity.

5, according to claim 3 or 4 described electrical conduction current lead-in wires, it is characterized in that:

Described superconducting metal wire is a strip metal silk.

6, superconductive current lead according to claim 1 is characterized in that:

Described second member is the Ag-Au alloy of a gold content less than 15 atom %.

7, superconductive current lead according to claim 1 is characterized in that, described second member is an Ag-Au alloy that contains 1 to 10 atom %Au.

8, superconductive current lead according to claim 1 is characterized in that:

Each described superconducting metal wire is a strip metal silk, and wherein said first member coats described second member, and described second member is an Ag-Au alloy that contains 1 to 10 atom %.