Patent ID: 7487839
Filing Date: 2009-02-10
Classification: E21B

Abstract:
1. A system for controlling vertical movement of a pipe through a stripping ram, said ram having an open position wherein an enlarged collar on said pipe may pass through said ram and a closed position wherein passage of said collar through said ram is blocked, said system comprising: a throttle for controlling an actuator, said actuator configured for initiating said vertical movement of said pipe; a selector valve in pneumatic communication with said throttle via a first pneumatic line, said selector valve responsive to said open and closed positions of said ram; a ram controller in pneumatic communication with said ram for switching between said open and closed position of said ram, said ram controller controlling said selector valve; a switch having first and second positions, first and second pneumatic inlets and first, second, and third pneumatic outlets, said switch connected: from said first inlet to said selector valve via a second pneumatic line; from said second inlet to said selector valve via a third pneumatic line; from said first outlet to said actuator via a fourth pneumatic line; from said second outlet to an exterior of said system; and from said third outlet to said actuator via a fifth pneumatic line; wherein when said ram is open and said switch is in said first position, air flows from said throttle via said first and second pneumatic lines into said first inlet of said switch and thereafter from said first outlet to said actuator, thereby enabling said vertical movement of said pipe; wherein when said ram is closed and said switch is in said first position, air flows from said throttle via said first and third pneumatic lines into said second inlet of said switch and thereafter from said second outlet to said exterior, thereby preventing actuation of said actuator and preventing vertical movement of said pipe; and wherein when said ram is closed and said switch is in said second position, air flows from said throttle via said first and third pneumatic lines into said second inlet of said switch and thereafter from said second outlet to said actuator, thereby enabling said vertical movement of said pipe.