Electricity: conductors and insulators – Conduits – cables or conductors – Superconductors
Reexamination Certificate
1996-12-16
2001-11-06
Paladini, Albert W. (Department: 2841)
Electricity: conductors and insulators
Conduits, cables or conductors
Superconductors
C174S015400, C505S230000, C505S231000, C505S234000, C505S431000
Reexamination Certificate
active
06313408
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an high Tc (Critical Temperature) superconducting cable conductor employing an oxide superconductor, and more particularly, it relates to an insulated superconducting cable conductor having flexibility, which is applicable to a superconducting cable.
2. Description of the Background Art
In relation to an oxide superconductor which enters a superconducting state at the liquid nitrogen temperature, expected is application to a superconducting cable with a cooling medium of liquid nitrogen. When such application is implemented, it may be possible to simultaneously attain simplification of a thermal protection system and reduction of a cooling cost, which are necessary for a metal superconducting cable requiring high-priced liquid helium.
A number of superconducting cables have been prepared from metal superconductors, followed by increasing study of insulating materials therefor. In relation to such insulating materials, the dielectric breakdown characteristic, the dielectric characteristic and the insulating life are taken into consideration on the premise that the same are not cracked under cooling temperatures. In relation to a metal superconducting cable, however, it has not been particularly necessary to consider influence exerted on the critical current by an insulating material as employed, since a metal superconductor has relatively high mechanical strength and exhibits an extremely high critical current density at the liquid helium temperature in a state with no application of a magnetic field.
In an oxide superconducting wire such as a bismuth based oxide superconducting wire which is stabilized by silver, the critical current density at the liquid nitrogen temperature is about {fraction (1/10)} that at the liquid helium temperature at present. In the oxide superconducting wire, therefore, influence exerted on the critical current by the insulating material is more significant as compared with that in the metal superconductor. Further, an oxide superconducting wire containing ceramics is inferior in resistance against mechanical strain as compared with the metal superconducting wire. When an oxide superconducting wire is subjected to remarkable bending in preparation of a cable, for example, its critical current may be extremely reduced.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an insulated oxide superconducting cable conductor which is excellent in superconductivity with a high critical current and a high critical current density, in particular.
Another object of the present invention is to provide an insulated oxide superconducting cable conductor having flexibility.
According to the present invention, provided is an insulated superconducting cable conductor having a plurality of tape-shaped multifilamentary oxide superconducting wires, which comprises an elongated former, the plurality of tape-shaped multifilamentary oxide superconducting wires spirally wound on the former at a bending strain in a prescribed range, and a tape-shaped insulating material spirally wound on the superconducting wires. In this insulated superconducting cable conductor, the tape-shaped multifilamentary oxide superconducting wires are superposed on the former in layers, so that stabilizing materials of the superposed tape-shaped multifilamentary superconducting wires are in contact with each other. The tape-shaped insulating material consists essentially of a material which is contracted at a thermal contraction rate of at least three times that of the tape-shaped multifilamentary superconducting wires by cooling from room temperature to liquid nitrogen temperature. Thus, the tape-shaped insulating material can supply a pressure from itself to the superposed tape-shaped multifilamentary superconducting wires toward the former by cooling in employment so that electrical contact between the superposed tape-shaped multifilamentary superconducting wires can be improved by cooling in employment.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4031310 (1977-06-01), Jachimowicz
patent: 4265932 (1981-05-01), Peters et al.
patent: 4883922 (1989-11-01), Yokota et al.
patent: 5017277 (1991-05-01), Yoshida et al.
patent: 5276281 (1994-01-01), Sato et al.
patent: A-0 235 522 (1987-01-01), None
patent: 0 329 179 (1989-02-01), None
patent: A-0 412 442 (1991-02-01), None
patent: 2 231 587A (1990-11-01), None
patent: 0207419 (1990-08-01), None
patent: 4-277410 (1992-10-01), None
Patent Abstracts of Japan, vol. 17, No. 525, Sep. 21, 1993 and abstract of JP-A-05 144333, Jun. 11, 1993.
Patent Abstracts of Japan, vol. 18, No. 155, Mar. 15, 1994 and abstract of JP-A-05 334921.
Sutton, “Induced circumferential currents and losses in flexible superconducting cables”, Cryogenics, pp. 541-545, Sep., 1975.
Appl. Phys. A 48, 527-542 (1989), “Laser-Induced Formation and Surface Processing of High-Temperature Superconductors”, by D. Bauerle.
Appl. Phys. Lett. 52 (25), Jun. 1988, “Plasma emission from laser ablation of the hgih-temperature superconductor YBa2Cu3O7”, by Wayne A. Weimer.
J. Appl. Phys. 67(8), Apr. 1990, “Optical emission spectroscopy during sputtering of Y-Ba-Cu-oxide targets”, by C.B. Fleddermann.
Fujikami Jun
Hara Tsukushi
Ishii Hideo
Sato Ken'ichi
Paladini Albert W.
Pennie & Edmonds LLP
Sumitomo Electric Indusstries, Inc
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