| 摘要 |
A drill string safety valve operator provides a rotatable tubular body having a longitudinal through bore for conveying fluids. A valve member is movably disposed within the body for valving the fluid flow through the bore. A crank arm extends from and is coupled to the valve member at the valve stem for moving the valve member between open flow and closed flow positions responsive to rotation of the crank arm. A bearing is carried at the outboard end of the crank arm for transmitting load to the crank arm. An annular ring is supported about the tubular housing and provides a surface that can engage the bearing. Hydraulic cylinders power the annular ring so that the annular ring engages the bearing. Downward movement of the ring causes a corresponding downward movement of the bearing and a corresponding rotation of the crank arm. The apparatus thus allows quick remote closure of the valve during a blowout condition of the drill pipe bore.
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