| 摘要 |
1537349 Cables INDUSTRIE PIRELLI SpA 24 Nov 1976 [5 Dec 1975] 49050/76 Heading H1A A cable having a plurality of insulated hollow conductors 1 is made by a process which avoids the absorption of ambient moisture in the course of production, which process comprises individually insulating each conductor 1 with lapped tapes 3 of insulating material to form a plurality of cores, each conductor having a central duct 2 extending longitudinally thereof, evacuating and drying each core and impregnating each core with an electrically insulating fluid, applying a tubular metal sheath 4 to each impregnated core, laying-up together the plurality of sheathed cores, and applying a protective layer 7 around the laid-up plurality of cores. In the described embodiment the insulating material is paper, which is impregnated with a fluid such as an alkylbenzene or a mineral oil. Reinforcing 5 such as metal tape covered with a sheath of plastics material such as polyethylene or PVC is provided over the insulating material. Screens of conductive material may be provided over each uninsulated conductor and over the unreinforced insulating material. The spaces between the cable cores can be filled with any suitable filler 6. The protective layer 7 can comprise metal armouring covered with bituminous material. |
