Metal-to-metal ribbed seal

Claim 1

A metal-to-metal seal for use in a high pressure environment typical of a wellhead assembly that is provided on a high pressure, high temperature gas well, comprising: a tubular part having an outside circumferential surface leading to an end; a relatively massive part having an internal chamber with an inside circumferential surface; the tubular part being coaxially at least partially received in said internal chamber so that said inside circumferential surface of the relatively massive part surrounds said outside circumferential surface of the tubular part; adjustable securement means associated with said tubular part and said relatively massive part for telescoping the tubular part into the internal chamber of the relatively massive part until a predetermined relative axial disposition of these parts is achieved; said inside circumferential surface having a taper, said outside circumferential surface being relieved so as to have a substantially complementary taper over most of the axial extent thereof, but having at least one narrow band in which a respective prominant circumferential rib is externally formed on said tubular part on and intermediate the axial extent of said outside circumferential surface, said at least one narrow band being so prominant that when said adjustable securement means is adjusted to bring said tubular part and said massive part to said predetermined relative axial disposition is achieved, said at least one rib on said tubular part is in interference fit with said tapered inside circumferential surface on said relatively massive part, with a resilient circumferential engagement essentially characterized by incomplete crushing of said at least one rib.