Annular sealing element with self-pivoting inserts for blowout preventers

摘要

An improved annular sealing element for oil well blowout preventers includes a plurality of curved metal segments spaced apart at regular circumferential angles and imbedded in a resilient matrix forming a generally lenticular-shaped body with a hollow central bore. Each segment has a tooth-like upper plate section having a downwardly depending web which is pivotably joined to the upper surface of a wedge-shaped base plate. Pivotability in a vertical plane of the upper plate section relative to the base plate limits the force exertable by the sealing element on a drill string component within the bore of the element. A cylindrical pivot bar formed in the lower surface of the base plate of each segment is adapted to roll or self-pivot on the annular head of a driver piston, thus allowing the sealing element to be installed in existing blowout preventers without modification of the driver piston.