Method of manufacturing a sealed vessel having a safety valve

Abstract

A method of sealing a pressure vessel so that pressurized gas in the vessel is released if the temperature of the gas approaches a critical temperature. An end plate having a concave upper surface and a convex lower surface, is provided with a bore perforating the plate at a low point of the concave surface. A central portion of the plate surrounding the bore bending downwardly to the bore so as to define a cavity in the plate. The plate is oriented with the concave surface facing in an upward direction. An alloy pellet, having a melting point which is lower than the critical temperature, is provided onto the concave surface so that the pellet is gravitationally drawn to rest in the cavity. The end plate is then heated at a temperature higher that the melting point of the pellet so that the pellet is melted and plugs the bore. The end plate is then cooled to solidify the melted pellet in the cavity and in the bore. An open end of the vessel is then fitted with the end plate so as to seal the end closed, and the vessel is supplied with pressurized gas.