Manual override for hydraulic gate valve actuators

A gate valve structure comprising:

• a valve body having inlet and outlet flow passages with a valve chamber therebetween;
• a gate mounted in the valve chamber for movement between open and closed positions relative to said flow passages;
• an externally threaded valve stem extending from the gate and axially movable in opposite directions to move the gate between its open and closed positions;
• a piston connected with said valve stem;
• a cylinder closely receiving said piston therein and presenting an enclosed pressure chamber on one side of the piston adapted to receive pressurized fluid to force the piston and valve stem in a first direction axially of the valve stem;
• a yieldable means for moving said piston and valve stem in a second direction opposite said first direction in the absence of fluid pressure in said pressure chamber above a predetermined level;
• an externally threaded nut member threadedly connected with said valve stem in a manner to effect axial movement thereof in said first direction in response to rotation of said nut member in a preselected direction;
• a sleeve received on said nut member in a sleeved relationship therewith and adapted to be rotated from the exterior of the valve body;
• a longitudinally extending spline connection between said sleeve and nut member translating rotation of said sleeve into rotation of said nut member but permitting relative movement between said sleeve and nut member axially of said valve stem, whereby said sleeve may be rotated to effect axial movement of said stem in said first direction against the force of said yieldable means;
• a watertight indicator housing mounted to said cylinder in a sealed relationship therewith and formed of transparent material so that the interior of said indicator housing is visible from the exterior of the valve body;
• and
• an indicator member coupled with said valve stem for movement therewith to provide a visual indication of the position of said gate, said indicator member being located within said indicator housing and being visible therein from the exterior of the valve body.

A gate valve structure comprising:

• a valve body having inlet and outlet folw passages with a valve chamber therebetween;
• a gate mounted in the valve chamber for movement between open and closed positions relative to said flow passages;
• an externally threaded valve stem fixed to the gate for reciprocation therewith and movable with the gate between its open and closed positions;
• a piston connected with said valve stem;
• a cylinder closely receiving said piston therein and presenting an enclosed pressure chamber on one side of the piston adapted to receive pressurized fluid to force the piston and valve stem in a first direction axially of the valve stem;
• yieldable means for moving said piston and valve stem in a second direction opposite said first direction in the absence of fluid pressure in said pressure chamber above a predetermined level;
• an internally threaded nut member threadedly connected to and moving longitudinally with said valve stem;
• a pair of spaced apart abutments so located as to be engaged by said nut member to prevent the nut member from moving axially on said valve stem beyond limiting positions, said valve stem thereby moving axially upon continued rotation of said nut member after either limiting position has been reached;
• a sleeve received on said nut member in a sleeved relationship therewith and adapted to be rotated from the exterior of the valve body;
• and
• longitudinally extending spline means connecting said sleeve and nut member in a manner translating rotation of said sleeve into rotation of said nut member but permitting relative movement between said sleeve and nut member axially of said valve stem, whereby said sleeve may be rotated in opposite directions to effect axial movement of said stem in both said first and second directions to move said gate between its open and closed positions.

A double acting manual override mechanism for a gate valve having a piston movable in opposite directions to open and close a gate valve member, a cylinder closely receiving said piston and adapted to receive pressurized fluid to move said piston in a first direction, and means for moving the piston in a second direction opposite said first direction when the pressure in said cylinder is below a predetermined level, said override mechanism comprising:

• an externally threaded shaft secured to the piston and movable axially to move the piston in opposite directions;
• an internally threaded nut member threaded onto said shaft for longitudinal movement therewith;
• means for limiting movement of said nut member axially along said shaft in both directions, said nut member being rotatable in opposite directions to effect movement of said shaft in both axial directions after limiting positions of the nut member are reached;
• a sleeve received on said nut member and adapted to be rotated manually;
• and
• a plurality of splines connecting said sleeve with said nut member in a manner translating rotation of said sleeve into rotation of said nut member but permitting relative movement between said sleeve and nut member axially of said shaft, whereby said sleeve may be rotated manually in opposite directions to move said shaft and piston in both said first and second directions to open and close the gate valve member.

In a subsea gate valve having a valve body with inlet and outlet flow passages and a valve chamber, a gate mounted in the valve chamber for movement between open and closed positions relative to the flow passages, an externally threaded valve stem extending from the gate and connected to a piston, a cylinder closely receiving said piston and adapted to receive pressurized fluid to force the piston and valve stem in a first axial direction, and resilient means urging said piston and valve stem in a second direction opposite said first direction, the improvement comprising:

• an internally threaded nut member threadedly connected with said valve stem in a manner to effect movement thereof in said first direction against the force of said resilient means upon rotation of the nut member in a preselected direction;
• a sleeve received on said nut member in a sleeved relationship thereto and adapted to be rotated from the exterior of said valve body;
• spline means connecting said sleeve with said nut member to rotate said nut member in response to rotation of said sleeve but permitting relative movement between said nut member and sleeve axially of said stem, whereby said sleeve may be rotated to rotate said nut member in said preselected direction to effect axial movement of said stem in said first direction;
• an axial extension of said stem projecting away from the gate;
• a transparent housing receiving said extension in a sealed relation and presenting a fluid tight compartment;
• and
• an indicator member carried on said extension within said compartment, said indicator member being visible through said transparent housing to provide a visual indication of the position of the gate.