Leakage monitor for HV metal clad switchgear - has two concentric gaskets in series and elastic seal in smooth bore

摘要

Leakage of compressed gas (e.g. SF6) past a toroidal gasket seated in a groove on the face of a flange results in flow through a narrow bore connecting the space between successive gaskets with a smooth radial bore. The conventional screw and gasket fitted into this radial bore are replaced by a wedge plug comprising a screw, an underlying washer, a tubular elastic (e.g. rubber) seal and a nut. The screw is threaded at its end only, the part nearest to the head being left smooth to ensure a gastight contact within the tubular seal, which surrounds it and is gripped between the washer and nut. To check for leakage, the screw is withdrawn and a whistling noise betrays any presence of compressed gas within the bore. Machining of the device is simplified and its cost reduced.