GB483203A - Improvements in and relating to electric liquid-blast circuit interrupters - Google Patents

Abstract

483,203. Liquid - blast switches. BRITISH THOMSON-HOUSTON CO., Ltd. July 30, 1937, No. 21203. Convention date, Aug. 1, 1936. [Class 38 (v)] An H.T. circuit-breaker comprises a pressure-confining chamber containing an are-extinguishing liquid, relatively - movable contactstructure arranged upon opening of the circuit to form an arc within the chamber, and a plurality of insulating tubes supported by and extending from the side wall of the chamber to a position adjacent the path of the arc and forming passages which exhaust exteriorly of the chamber. The breaker shown is of the type in which an initial arc set up between a fixed and an intermediate contact 1, 2 causes a blast of liquid across the path of an arc subsequently set up between contact 2 and the movable contact 3, and at the exhaust 4<1> of an insulating pot 4, which may be a laminated structure impregnated with artificial resin. For quenching the arc within the pot 4, four insulating tubes 14, for example of hard fibre, are arranged with their inner ends adjacent and along the arc-path, and, if desired, so closely to the contact 3 that they are successively uncovered by the latter in its opening movement. Their outer ends exhaust exteriorly of the pot 4, to which they are secured at 14<1>, and are preferably angularly spaced in order to prevent flash-over outside the pot due to combining of the gas-bubbles. The tubes 14 provide a large voltage-creepage surface between their inner openings by reason of the tube-surfaces which extend transversely of the arc. When, in opening circuit, 3 separates from 2, the arc therebetween will first be subjected to a blast through the upper tube, subsequent jets acting upon the arc as it is drawn past the other tubes.