GB605217A - Improvements in or relating to gas-blast electric circuit-breakers - Google Patents

Abstract

605,217. Gas-blast switches. REYROLLE & CO., Ltd., A., and AMER, D. F. Dec. 18, 1945, No. 34216. [Class 38 (v)] In a gas-blast circuit breaker having a gas delivery-chamber or reservoir on the highpressure side of a nozzle, and a blast-valve at the outlet side of an exhaust-chamber on the low-pressure side of the nozzle, an exhaust-valve is arranged in tandem with the blast-valve, the valves being sequentially-controlled by a single control-device, so that during opening of the breaker the blast-valve is opened before the exhaust-valve is closed, and during closure of the breaker the exhaust-valve is opened before the blast-valve is closed. In Fig. 1 a rotary control shaft F in the base of a post insulator A, is connected through a crank F<1> and an insulating rod F<2> to the exhaust-valve C<4>, and through toggle-linkages C<5>, E' to the blast-valve E and a pair of series-connected movable-contacts G. The breaker is opened by rotation of the shaft F, the valve E opening before the valve C' closes, arid before the contacts G, D<2> separate, so that gas flows through the exhaust-chamber D, an expansion-chamber C, and a non-return valve C<1> to atmosphere. When the valve C<4> closes the contacts G, D<2> separate, and a stream of arc-extinguishing gas flows from the reservoir B through the nozzles D<1>, and expands into the chamber C, the build-up of back-pressure in the chamber D being delayed until the arc is extinguished. The exhaust-gases are, for the most part, held and cooled in the chamber C until the breaker is reclosed, the valve C<4> then opening before the valve E closes, so as to discharge the exhaust-gases and at the same time scavenge the chambers D, C. As the togglelinkage E<4> re-closes the contacts G, the valve E closes and restores the pressure in the chamber D. In metal-clad withdrawable switch-gear, Fig. 4, the expansion-chamber H and exhaust-chamber J are arranged wholly within the reservoir L, and the chamber J has an extension J<2> with nozzles J<3>, J<4>, in alignment with contacts K, K<1>, the extension J<2> being connected to the contact K<1> through a resistance M<2>. In an open-type circuit-breaker, Fig. 5 (not shown), the movable-contact co-operates with nozzles arranged in opposite walls of a plurality of conduits which communicate with the exhaust-chamber. In Fig. 6 (not shown) the contacts are arranged outside the reservoir, which has a cam-operated inletvalve, automatically-operable under fault-conditions.