Closure seal for high pressure vessel

摘要

Sealing between an access opening in a pressure vessel and a closure member fitted in the opening is provided by an O-ring of perfluoroelastomer in an annular groove formed in a surface of the closure member. The sidewall of the groove on the low pressure side of the seal has a concave curvature in cross section so as to form a "hook" or lip which retains the O-ring in the groove and prevents creeping extrusion of the O-ring under prolonged exposure to high temperature and pressure fluid on the high pressure side of the seal, even with a clearance between the closure member and the access opening of up to approximately 1 percent of the diameter of the O-ring cross section.