GB1439016A - Blowout preventers - Google Patents

Abstract

1439016 Wells &c HYDRIL CO 17 July 1973 34086/73 Heading E1F In a blowout preventer comprising a housing 10 and rams R, the rams carry yieldable seals 30 and anti-extrusion means 31 preventing upward extrusion of the material of the seals when the seals are in sealing position. A ram includes a carrier 20, a top plate 24 connected to the carrier by cap screws 26, a yieldable member 21 between the plate and carrier, a base plate 25 having a projection 25c engaging the carrier, and replaceable means including a seal 30 and the means 31. The means 31 comprises segments 35 moulded to the seal and segments 40 each overlapping a pair of segments 35, the segments 40 being connected to be moved by the segments 35. As the rams are brought together to seal about a pipe P the top and base plates first engage and further movement of the carriers forces the seal and the inner ends of the segments into engagement with the pipe. The segments may be designed so that the ram acts as a "blind ram". A lower anti-extrusion means 32 may be fitted, the anti extrusion means being effective when a non circular member such as a kelly is engaged, or when the pipe is engaged at a joint.