Cooper Industries, Inc.

Cameron Iron Works Usa, Inc.

Timothy C Davies

William M Taylor

Jerry D Smith

Thomas G Cassity

Larry M Hoes

Peer H Tiemer

Edward J Szymozak

The present invention relates to an improved metal-to-metal seal for a moving stem of a valve and includes a U-shaped ring having a base, an inner leg extending from the inner portion of the base and an outer leg extending from the outer portion of the base. The sealing surface of each leg is flattened and in its free position has a slight angle with respect to the axis of the seal. Each of the legs includes a support enlargement on its sealing side at a point toward the base from the sealing surface and preferably at the position of maximum deflection of the leg. The diameter of such supports is preselected so that in its free state they each are spaced a short distance from the walls against which their leg seals. The end of the outer leg is turned inwardly at an angle.

Valve stem seal

The improved wellhead structure of the present invention includes a casing or tubing string which is sealed to the housing without the aid of elastomeric seals and an internal bushing to assist in providing the tight gripping and sealing engagement between the string and the housing. The structure provides a substantial inner diameter which is unrestricted unless landing shoulder is included in the structure. Also, the internal bushing used with the cold forging of the string into the housing recess improves the gripping and sealing engagement therebetween. In one form the bushing includes a series of external projections which alternate with the gripping and sealing projections within the housing recess and in another form includes a resilient annulus between the interior of the bushing and the string to ensure the uniform application of pressure against the interior of the string. In still another form an internal landing shoulder is cold forged into tight engagement with the interior of the housing which allows full bore operations to be carried through the housing until the landing shoulder is to be installed. Also provided is a wellhead structure with a tieback structure in which the upper end of the casing is cold forged into the interior of a hanger while the casing is supported on slips.

Wellhead structure

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Leeds, United Kingdom

Timothy C Davies