Cut-off chamber for high-voltage electric circuit breaker

The chamber comprises, with a view to increasing the quenching power, a Coanda-effect nozzle (3), of the internal type, which has the effect of directing the flow of the quenching fluid over the wall of the nozzle from the instant of separation of the contacts (1, 2) and of cooling the zone of formation of the electric arc better. The nozzle is fixed in the extension of the moving contact (2). It can also be located in the extension of the two contacts in the case where these contacts are tubular. The nozzles can also be of the external type and be accommodated in the contacts themselves in the case where at least one of these contacts is tubular.