Security lock for pressure vessel etc. cover assembly

摘要

The Al cover assembly (18) presents a circular overpressure seal which either opens or yields under excessive pressure, notably by deforming due to the design stiffness of the assembly (18) which is carried so as to yield or open under this excessive pressure load, specifically using a stop unit (20) fitted to the annular shoulder part where this faces the fixer coupling (15). The seal (18) can be designed as a rupture or burst disc (30) whose section has radial lines of weakness (32). In another variant, the cover seal (18) is formed by a plate spring. The radial length (L) of the unit (18) bearing surface on shoulder (20) is such that any shortening of the sealing cover due to overpressure in turn frees the cover from the shoulder thus equalising the pressure, using a protective top (40) to shield the cover (18) as preferably bonded to the shoulder (20).