| 摘要 |
<p>A dual drill string valve includes an actuator (100) including a piston (114) disposed in a housing (110), which is configured to couple at its ends to an end of a nested dual drill string segment. An upper inner conduit (112) and a lower inner conduit (115) are mounted in the housing, proximate to the longitudinal ends thereof. The piston is slidably, sealingly engaged between the upper and lower inner conduits and defines a fluid flow passage therethrough. The upper inner conduit, the piston and the lower inner conduit define another flow passage between respective exterior surfaces thereof and an interior of the housing such that application of fluid pressure to the external flow passage causes movement of the piston away from the upper inner conduit. A rotary valve is coupled to the actuator whereby longitudinal movement thereof rotates the rotary valve.</p> |
