Patent ID: 7032768

Claim:
An end closure device for a steel-body gas storage vessel, wherein said steel-body gas storage vessel has an interior surface defining a volume and at least one vessel end piece having a rim and a threaded interior surface, wherein said vessel interior surface and said vessel end piece interior surface are covered by a corrosion resistant, metal coating which is inert relative to the gas to be stored in said vessel, comprising: a. a sealing portion being formed from a first metal that is corrosion resistant and inert relative to the gas to be stored in said vessel, and having an annularly disposed sealing gland retained on the surface thereof, and b. a securing portion being formed from a second metal of greater strength than the first metal, having exterior-engaging threads for engaging the interior threads of said vessel end piece such that seating said end closure device in said vessel end piece facilitates sealing engagement of the sealing gland with said vessel end piece by radially compressing the sealing gland between the interior surface of the coated vessel end piece and the surface of the sealing portion.