| 摘要 |
<p>A barrier valve has an equalizing feature for the ball or plug when in the closed position before it is opened. A hydraulic open and a close line are connected to a housing so that they can move a piston in opposed directions. The piston ends are sealed and the exterior of the piston is tapered to push one or more bypass valves open to connect tubing pressure across the ball when ramped off its seat. Pressure on the main hydraulic line to close the ball reverses the piston movement and allows a spring bias to close the bypass valve or valves. The equalizing system can be integrated into the barrier valve housing or can be separate as a retrofit.</p> |
