ACTUATOR WITH AUTOMATIC LOCK

摘要

2074832 9111624 PCTABS00006 An improved blowout preventor actuator (20) is provided for opening and closing a ram block (26) within a blowout preventor body (12) to control the flow of well fluid. The working or power piston (30) within the actuator cylinder (46) is provided with one or more axially extending cavities (68) each for receiving a locking rod (42) secured at one end to the cylinder head (32). To prevent inadvertent opening of the ram block (26), locking segments (92) carried by the power piston (30) repeatedly disengage one locking surface and re-engage an adjacent locking surface on the locking rods (42) as the power piston (30) and ram block (26) secured thereto move to the ram closed position. To unlock the power piston (30) from the locking rods (42), fluid pressure is applied to an unlocking piston (80) which radially moves the locking segments (92) out of engagement with the locking rods (42). The locking surfaces on the locking rods (42) extend axially along a length which allows different ram blocks (26) to be substituted for sealing with various diameter tubular members (16) passing through the blowout preventors (10). The simple yet highly reliable technique for preventing opening of the BOP ram block (26) increases safety and reduces manufacturing and operating costs.