Control valve system for blowout preventers
AssigneeNL Industries, Inc.
InventorH. John Bates
Life of this patent
Estimating the term…
Abstract
A control valve system and method are disclosed for blowout preventers having an actuating piston for actuating the closing of the blowout preventer whereby the piston has an opening side and a closing side. The control valve system and method include a means for selectively directing fluid from the opening side of the actuating piston to the closing side of the actuating piston in order to reduce the fluid requirements for closing the blowout preventer and reduce in stalled horsepower requirements thereby.
Claims7
In a method of reducing fluid capacity requirements and installed horsepower requirements of blowout preventers having an actuating piston for actuating the closing of the blowout preventer, the piston having a closing side and an opening side of smaller effective area than the closing side, the steps of:
- (a) injecting fluid on the opening side of the actuating piston in order to move the actuating piston to an open position;
- (b) selectively injecting fluid under pressure on the closing side of the actuating piston in order to initiate the movement of the actuating piston to close the blowout preventer;
- (c) selectively directing the fluid forced from the opening side of the actuating piston by the movement of the actuating piston in step (b) to the closing side of actuating piston until a predetermined pressure is obtained in the system;
- and
- (d) after a predetermined pressure is developed in the system, redirecting the fluid forced from the opening side of the actuating piston to discharge to a reservoir.
For use with blowout preventers having an actuating cylinder and piston for actuating the closing of the blowout preventer, the piston having a closing side and an opening side of smaller effective area than the closing side, a differential pressure control valve system comprising:
- a directional flow control system for selectively directing flow from the opening side of the actuating piston alternatively to the closing side of the actuating piston and to a discharge point upon the closing of such a blow out preventer, including
- a control cylinder having a bore with inner diameter, a return end, and a retracting end, the retracting end being in communication with the closing side of the actuating piston,
- a control cylinder piston slidably mounted in the control cylinder for longitudinal movement, the piston having a longitudinal width of less than one-half the length of the control cylinder and a configuration which snugly fits the inner diameter of the control cylinder, wherein the control cylinder further communicates with the opening side of the actuating piston at a point along the length of the control cylinder which accommodates the communication of fluid from the opening side of the actuating piston into the control cylinder when the control cylinder piston is at either end of the control cylinder, and
- a switching mechanism for selectively moving the control cyliner piston from one end to the other;
- and
- a pressure sensitive switching system operatively associated with the directional flow control system for selectively varying the alternative flow paths of the directional flow control system at a predetermined pressure level.
Dependencies are inferred from the claim text.