| 摘要 |
1167054 Cooling cables SIEMENS A G 6 April 1967 [6 April 1966 19 April 1966] 15838/67 Headings H1A and A4D An electrical transmission cable comprises a conductor surrounded by thermal insulation, including an evacuable cavity, in turn surrounded by electrical insulation. As shown in Fig. 1, a tubular, ultra-pure aluminium conductor 1 has a cavity 2 for the passage of a coolant, such as gaseous helium. Thermal insulation is provided by the evacuable cavity between composite plastics corrugated tubes 3, 4, which have a mirror finish on the sides adjacent the cavity and which are spaced apart by helically extending plastics strips 5. The outer surface of tube 4 has a semi-conducting coating 6, such as metallized or carbon-loaded paper, connected to conductor 1 and electrical insulation inside protective jacket 8. The outer tube 4 may be of metal, or both tubes may consist of helically wound metal strips sealed with plastics tape Figs. 4a, 4b (not shown). The low temperature conductor may be built of a large number of insulated individual cores whose radial positions vary along the length of the conductor Fig. 3 (not shown). In a super-conducting cable Fig. 2 (not shown) the conductor comprises a steel tube (9) insulated from a super-conductive coating (10) and the cable is disposed inside a pressure tube (11) with oil under pressure passing through the gap between insulation 7 and tube (11). In another embodiment, shown in Fig. 5, the cable is subdivided into tubular component elements 21, each having a large number of cores, and cooling channels 22. A helium-tight plastics tube 23 with glass fibre tape reinforcement 24 surrounds elements 21 and prevents leakage of gas into the evacuable cavity 25. The electrical insulating tube 26 has semi-conducting layers 27, 28 and a protective jacket 29 surrounds tube 26. The individual conductors of component cables 21 may be disposed around a metal tube (30), Fig. 6 (not shown), or cables 21 may be disposed around a single elliptical metal tube (31), Fig. 7 (not shown). |
