| 摘要 |
An automatic by-pass valving system for an electrical cable system wherein insulating fluid at a pressure above atmospheric pressure is supplied to an electrical power cable, such as a pipe-type or self-contained cable, having a fluid flow channel and having at least one hydraulic stop interrupting the flow of fluid between the channels of adjacent portions of the cable which are at different elevations. The valving system comprises a check valve, which allows fluid flow only in a first direction, from the lower elevation portion to the higher elevation portion, and a flow-limiting valve, which allows fluid flow only in a second direction, from the higher elevation portion to the lower elevation portion, at a reduced rate. Preferably, a relief valve is also provided to allow fluid flow in the second direction at a higher rate if the fluid pressure difference in the second direction is exceeded by a predetermined amount. The valving system limits the loss of the insulating fluid from the cable when the lower elevation portion is ruptured, protecting the environment, while permitting a limited flow from the point of rupture to protect the cable from contamination.
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