Mud saver kelly valve
AssigneeSmith International, Inc.
InventorDavor Majkovic
Life of this patent
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Abstract
A mud saver valve is described that features an outer housing that retains upper and lower valve pistons therewithin. The pistons coordinate to provide a check valve so that fluid, such as drilling mud, is permitted to flow in one direction while under pump pressure and works as a relief valve in the event of excessive wellbore pressure when the pump is turned off. Both pistons are provided with apertured plates that selectively define fluid passages through the valve. In the described embodiment, the valve also includes a frangible vent cap that is self-securing and easily replaceable. The cap permits venting of excessive downhole pressures.
Claims16
A frangible vent cap for a kelly valve comprising:
- a) a frangible central body;
- and
- b) at least one perpendicularly-extending collet finger having a radially-outwardly protruding lip to facilitate insertion of the vent cap into a surrounding opening and to prevent withdrawal of the vent cap from the surrounding opening.
A vent cap comprising:
- a frangible central body;
- means to facilitate insertion of the vent cap into a surrounding opening;
- means to prevent removal of the vent cap from the surrounding opening;
- and
- means for venting a fluid under pressure through the vent cap;
- wherein the frangible central body is not removeable from the means to facilitate insertion or from the means to prevent removal.
Dependencies are inferred from the claim text.