Single-pole breaking unit comprising a rotary contact bridge, and a switchgear device, and circuit breaker comprising such a unit

Abstract

A single-pole breaking unit which includes a rotary contact bridge, a stationary contact operating with the contact bridge and connected to a current input, a rotary bar having radially extending axial end surfaces, and radial side surfaces with a transverse hole for the contact bridge which is salient through opposite radial side surfaces of the bar, an arc extinguishing chamber opening onto an opening volume for the contact bridge, two parallel side panels parallel to the axial end surfaces of the bar, with the rotary bar located between two sealing flanges between the axial end surfaces of the rotary bar and the side panels and movable axially toward the side panels to ensure tightness between the inside and the outside of the breaking unit, the sealing flanges each comprising a radially extending portion, and a cylindrical portion, both co-axial with the rotary bar, which cylindrical portion has an inside radius slightly less than the radial extent of the rotary bar, providing a space between the inside surface of the cylindrical portion and the rotary bar, the space permitting quenching gases to flow directly to push a sealing flange axially against a side panel to achieve tightness.