Two way valves in pressure balancing pipes - suppress contaminated gas flow in gas insulated switchgear by reacting to pressure rise

摘要

To prevent undesirable flow of contaminated gas into clean parts of the system following a fault the bridging pipes are provided with two way pressure sensitive valves. These valves close due to sudden flow caused by a pressure rise consequent upon the heat generated by a fault. The defective portion is thus transiently isolated. A valve may comprise a local pipe section of larger diameter (14) with flanged ends (3), containing a disc (5) held by springs (6) on each side. A sudden increase in pressure and flow will push the disc in the flow direction until it seals onto the flange face (7) and prevents further gas transfer. With subsequent pressure reduction the disc returns to its normal position under spring action.