Pirelli Cable Corporation

Bryan Gaines

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.

Automatic by-pass valving systems and methods

A method of controlling insulating fluid flow between fluid channels in sections of an electrical power cable at different elevations, the channel of one section being isolated from the channel of a next adjacent section by a hydraulic stop, to limit the loss of insulating fluid when a seciton is ruptured and yet permit a limited flow from the point of rupture to protect the cable from contamination. Fluid at a high rate from a lower section to adjacent higher sections around the stop is permitted by a check valve which substantially prevents fluid flow in the opposite direction and a flow-limiting valve permits fluid flow at a low rate from the higher section to the lower section. The fluid pressure difference between the sections may be relieved by a relief valve if the difference exceeds a predetermined amount.

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Lexington, SC, United States of America

Bryan Gaines