| 摘要 |
1502714 Cooling cables INDUSTRIE PIRELLI SpA 5 March 1976 [14 April 1975] 08985/76 Heading F4U [Also in Division H2] A method of displacing electrically insulating oil to and fro along at least three separate oilfilled ducts 10-12 joined togeIher at one end by a common pipe 35, said ducts being formed in one oil-filled electric cable or distributed over a plurality of oil-filled electric cables, comprise the step of operating pumping apparatus so that, in a continuous cycle of operation, oil is displaced along each duct in turn towards the said one end, with the oil which issues from each duct in turn passing back along the other two or more ducts. In the embodiment shown, each duct is in communication with a tank 13-15 subdivided into first and second variable volume chambers by a bellows 23-25. The cables are fitted with electrically insulating oil and the pumping apparatus with lubricating oil. The pumping apparatus includes a pump 16, a reservoir 42, and electrically operable valves 36-41 for controlling the continuous cycle of operation. In another embodiment (Fig. 4, not shown), further centrifugal pumps (46-48) are associated with each tank 13-15. |
