| 摘要 |
<p>PCT/US90/01687 A subsea barrier valve (20) with a valve clapper (60) adapted for free swinging movement on a clapper shaft (62) between a position which closes the flow passage through the valve and a position proximate the fully open position such that the clapper is held open by a pressurized flow of gas through the-valve. In the event of an upstream pipeline failure, the clapper close in a "fail-safe" manner. The clapper can be pivoted and locked in the full open position by axial rotation of a locking shaft (105) which extends through a cover member (30) for an access opening in the valve body (21). The locking shaft (105) extends perpendicular to the clapper shaft (62) and is interconnected therewith by a gear drive (106) including a clutch gear (126) which allows a limited range of free pivotal movement of the clapper (60).</p> |
