Pilot close vent valve
AssigneeNational Oilwell Varco, L.P.
InventorsTravis James Miller, Frank Benjamin Springett, James William Weir, James Landrith
Life of this patent
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Abstract
A valve for use in a hydraulic circuit to drive a piston is fluidly connected to a first actuating chamber of the hydraulic piston. The valve is piloted to close when the first chamber is pressurized. The valve vents the fluid in the first actuating chamber when the first chamber is not pressurized. The valve permits several fluid supplies connected to the chamber via check valves to be used to drive the piston. The hydraulic piston and hydraulic circuit may be implemented in a blowout preventer operating in a subsea environment to ensure safe drilling of deepwater wells.
Claims20
A valve, comprising:
- a body having a cavity therein;
- a first seal plate positioned in the cavity, the first seal plate comprising a first opening fluidly connected to a first source port;
- a shuttle positioned in the cavity, the shuttle including:
- a piston head for sealing a first chamber in the cavity from a second chamber in the cavity, and
- a first stem extended from a first face of the piston head into the first chamber, the shuttle being reciprocable in the cavity between a first end of stroke position wherein the first stem abuts the first seal plate and closes the first opening in the first seal plate, and a second end of stroke position wherein the first stem is separated from the first seal plate by a gap and a flowpath is established from the first source port through a first portion of the first chamber and into a first vent port;
- wherein the first vent port is fluidly connected to the first portion of the first chamber;
- a first pilot port;
- and
- a pressure communication between the first pilot port and a first portion of the second chamber configured such that the first pilot port remains continuously in pressure communication with the first portion of the second chamber at any position of the shuttle intermediate between the first and second end of stroke positions.
A method of controlling a movable component, comprising:
- providing a valve, the valve including a body having a cavity therein, a first seal plate positioned in the cavity, the first seal plate comprising a first opening fluidly connected to a first source port, a shuttle positioned in the cavity, the shuttle including a piston head sealing a first chamber in the cavity from a second chamber in the cavity, a first stem extending from a first face of the piston head into the first chamber;
- a first vent port fluidly connected to a portion of the first chamber, and a first pilot port in pressure communication with a portion of the second chamber;
- connecting a first function port of the movable component, a plurality of fluid supplies, and the first source port with a first flowline;
- coupling the first pilot port to the plurality of fluid supplies;
- displacing the shuttle in the cavity to a first end of stroke position wherein the first stem abuts the first seal plate and closes the first opening in the first seal plate by applying pressure from at least one of the plurality of fluid supplies to the first pilot port;
- displacing the shuttle in the cavity to a second position wherein the first stem is separated from the first seal plate by a gap and a flowpath is established from the first source port through the portion of the first chamber and into the first vent port;
- and
- discharging backflow from the first function port through the first vent port.
Dependencies are inferred from the claim text.