Puffer-type gas-blast circuit breaker

Abstract

A puffer type gas-blast circuit breaker includes at least one interrupting unit mounted in a vessel filled with an arc-extinguishing gas of a unitary pressure. The interrupting unit comprises: a fixed contact; a movable contact movable toward and away from the fixed contact to be engaged with and to be disengaged from the fixed contact respectively, the movable contact having therein an axial hollow portion, wherein an arc is established between the contacts upon disengagement of the movable contact from the fixed contact; a compression chamber filled with an arc extinguishing gas; a suction chamber, wherein an arc extinguishing gas within the compression chamber is compressed and the volume of the suction chamber is enlarged upon movement of the movable contact away from the fixed contact, and wherein a pressure difference between the compression chamber and the suction chamber causes the arc extinguishing gas to be directed from the compression chamber through the axial hollow portion into the suction chamber thereby to be blown against an arc produced between the fixed contact and the movable contact; and means provided in the suction chamber for cooling an arc extinguishing gas introduced into the suction chamber to suppress a pressure rise within the suction chamber for maintaining a sufficiently large pressure difference between the compression chamber and the suction chamber, thereby shortening an arcing time and improving a breaking performance.