Patent ID: 9175538
Filing Date: 2015-11-03
Classification: E21B,F04B,Y10T

Abstract:
1. A recharging mechanism for use with a subsea pressure control device comprising: A vessel having a first vessel chamber and a second vessel chamber that is sealed and contains a gas; A vessel piston in the vessel that defines a barrier between the first and second vessel chambers, and that is selectively moveable between a low pressure position with a volume of the second vessel chamber greater than a volume of the first vessel chamber to a high pressure position with the volume of the first vessel chamber greater than the second vessel chamber; A selector valve for selectively communicating the first vessel chamber with a ram actuator of a blowout preventer (BOP), so that when the ram actuator actuates a ram in the BOP, a fluid is discharged from the ram actuator to fill the first vessel chamber and urge the vessel piston to the high pressure position and compress the gas in the second vessel chamber; A pumping device having a pump primary piston, a first pump chamber and a second pump chamber, the primary piston being movable within the second pump chamber of the pumping device and having a rod portion extending into the first pump chamber to change the volume of the first pump chamber when the primary piston and the rod portion move, the first pump chamber being in fluid communication with the first vessel chamber via an intake fluid line, so that as the piston moves in an intake direction and increases the volume of the first pump chamber, a pressure imbalance is created between the first pump chamber and the first vessel chamber so that fluid passes from the first vessel chamber to the first pump chamber via the fluid intake line, thereby decreasing the volume of the first vessel chamber; A hydraulic line connected to the first and second pump chambers that delivers hydraulic fluid to drive the pump primary piston; A discharge fluid line leading from the first pump chamber that discharges fluid from the first pump chamber when the primary piston and rod portion are moving in a discharge direction; and Valve means in the intake fluid line and in the discharge fluid line for preventing fluid in the discharge fluid line from flowing into the first pump chamber while the primary piston moves in the intake direction, and for preventing fluid in the first pump chamber from flowing through the intake fluid line into the first vessel chamber while the primary piston is moving in the discharge direction.