Patent ID: 7552765

Claim:
A production blowout preventer, comprising: a housing forming a central bore, which extends vertically through the housing, and a first and a second horizontal ram bore extending radially outwardly in opposite directions through the housing and intersecting the central bore, with sealing surfaces being formed across the wall surfaces at the intersection of the ram and central bores; a first ram positioned in the first ram bore for sliding movement therealong; a second ram positioned in the second ram bore for sliding movement therealong; the first and second rams each including a ram body having front and rear ends, each of the ram bodies being slidable along the ram bores so as to project into the central bore where their front ends are adapted to seal against a polish rod of a rod string extending therethrough; the first ram body including an extended central bore sealing section between its front and rear ends, said central bore sealing section carrying one or more central bore seals for sealing across the central bore when the extended central bore sealing section is positioned across the central bore in a central bore closing position; the one or more central bore seals including a saddle shaped seal of a thermoplastic material formed on the upper surface of the extended central bore sealing section and being shaped to span and seal across the central bore when in the central bore closing position; the first ram carrying lifting means for upwardly lifting the extended central bore sealing section to cause the saddle shaped thermoplastic seal to seal across the central bore in the central bore closing position; the first ram bore being of sufficient length to accommodate the first ram body in its fully extended or fully retracted position; the second ram bore being of sufficient length to accommodate the second ram body in its fully extended or fully retracted position, and to also accommodate the front end of the first ram when in the central bore closing position; and means connected to the rear of each ram body for advancing and withdrawing the first and second rams between open, sealing and central bore closing positions.