Closure assembly

Claim 1

A closure assembly for high pressure applications comprising: a substantially cylindrical hollow member having a first open end adapted for attachment to a pressure vehicle and an opposing externally threaded open end and having an internal surface between the ends; an annular projection extending from said open end, said projection including a thin wall portion and a sealing portion mounted to a distal end of said thin wall portion, said thin wall portion being thinner than said hollow member; said sealing portion including an annular internal surface and an external circumferential groove defined by a shoulder, an annular external surface, and a radially extending annular flange opposing said shoulder; an O-ring positioned within said groove; said thin wall portion including substantially flat, annular internal and external surfaces positioned a selected distance from the axis of said hollow member, the annular internal surface of said thin wall portion being spaced radially outwardly from the internal surface of said hollow member; said radially extending annular flange having a radially outermost surface defined within the radius of said flat annular external surface; said annular internal surface of said sealing portion being located radially inwardly with respect to said annular internal surface of said thin wall portion; and a cap having a closed end and an open internally threaded end for attachment to the threaded end of said hollow member, a substantially flat annular internal surface positioned within and adjacent to said threaded end, said substantially flat annular external surface of said thin wall portion being adjacent said substantially flat annular internal surface of said cap and said O-ring making sealing contact therewith when said threaded end of said cap is secured to said threaded end of said hollow member; said thin wall portion capable of dilating under pressure into contact with said cap.