GB544989A - Improvements in gas blast electric circuit breakers - Google Patents

Abstract

544,989. Gas-blast switches. BRITISH THOMSON-HOUSTON CO., Ltd. Dec. 23, 1940, No. 18045. Convention date, Dec. 22, 1939. [Class 38 (v)] In a switch of the general character disclosed in Specification 544,017, wherein a movable contact blade 11 is withdrawn from fixed contact fingers 10 in a close-fitting arc chute 20 across which air or gas from a conduit 21 is blown and forces the arc against the edges of fanwisearranged insulating barriers 22 of a material such hard fibre which evolves a gas under the archeat, the are chute opens into an insulating structure 24, which may be integral with the chute (or the whole may be fabricated of sheet insulation), having a horizontal barrier 29 to which one of the barriers 22 is secured so as to form spaces 26, 27. The space 26 communicates at its left-hand end and through the space below the barrier 29, with a space 30 with which the space 27 communicates directly. The passages 26, 27 have stacks of parallel metal cooling plates 31, 32, 33 spaced apart in the stacks by projections on the plates themselves. If the arc is quenched by the time the movable contact tip reaches the longer barrier, the blast issuing from the stack 32 consists mainly of fresh air which assists final combustion of any gases which are not completely burned when they leave the stack 33. Cooling plates 23 are also provided between the barriers 22 and a tube 25 for the exhaust gases.