Cryogenic cable and process for making the same

Claim 1

A cryogenic cable comprising an inner cylindrical metallic fluid-tight enclosure containing a plurality of electrical conductors and carrying a cryogenic fluid, a thermal screen mounted in spaced surrounding relationship to said inner enclosure, a plurality of cooling conduits mounted integrally with said thermal screen, an outer cylindrical metallic fluidtight enclosure mounted in spaced surrounding relationship to said thermal screen, support means for suspending the combination of said inner enclosure and said thermal screen within said outer enclosure, at least one perforated duct mounted adjacent said thermal screen within said outer enclosure for producing a vacuum between the inner and outer enclosures, thermal insulating means disposed in the space between said screen and said outer enclosure, a plurality of return cooling conduits disposed in the space between said screen and said outer enclosure and a plurality of additional return cooling conduits disposed in the space between said screen and said inner enclosure, said thermal screen being formed of a longitudinally curved metal band having the longitudinal edges thereof curved outwardly around said cooling conduits and in intimate contact therewith.