| 摘要 |
Disclosed is a safety valve with redundant operators or systems. One safety valve includes a piston bore in fluid communication with a first control line via first control line port and a second control line via a second control line port, the first and second control lines conveying hydraulic fluid pressure to the piston bore. First and second piston assemblies are movably arranged within the piston bore and the second piston assembly includes a transition member coupled thereto. A flow tube is arranged adjacent the transition member and moves axially within a flow passage defined in the safety valve in response to the movement of the transition member. A valve closure device moves between an open position and a closed position restricts fluid flow through the flow passage when in the closed position, the flow tube being adapted to shift the valve closure device between open and closed positions. |
