Rechargeable system for subsea force generating device and method

A recharging mechanism for use with a subsea pressure control device, comprising:

• a vessel for controlling subsea equipment, the vessel having a charged state in which the vessel is substantially filled with gas, and a discharged state, in which the vessel is substantially filled with fluid;
• a pump that includes a pump primary enclosure having a pump primary piston that divides the pump primary enclosure into first and second primary chambers;
• an auxiliary pump enclosure having an auxiliary piston rigidly connected to the primary piston, the auxiliary piston dividing the auxiliary pump enclosure into first and second auxiliary chambers, the first auxiliary chamber having a volume that increases as the primary piston moves the auxiliary piston in an intake direction, the first auxiliary chamber being hydraulically connected to the vessel via an intake line;
• at least one hydraulic line connected to the pump primary enclosure to drive the pump primary piston across the pump primary enclosure in the intake direction, thereby increasing the volume of the first auxiliary chamber as the auxiliary piston moves in the intake direction and drawing fluid out the vessel through the intake line into the first auxiliary chamber;
• a discharge line extending from the first auxiliary chamber for discharging fluid from the first auxiliary chamber when the primary piston moves the auxiliary piston in the discharge direction;
• and
• an intake line valve that prevents flow from the first auxiliary chamber into the vessel when the auxiliary piston moves in the discharge direction.

A subsea well drilling blowout assembly (BOP), comprising:

• A BOP piston located in a BOP chamber and movable between an open and a closed position:
• A vessel in fluid communication with the BOP chamber for receiving fluid from the BOP chamber as the BOP piston is moved toward the closed position;
• A pump having a primary piston and first and second primary pump chambers, the primary piston being movable in the second pump chamber and having a rod portion of smaller diameter than the primary piston and extending into the first pump chamber to increase a volume of the first pump chamber when the primary piston and the rod portion are moved in a fluid intake direction;
• A hydraulic line connected to the first and second pump chambers that delivers hydraulic fluid to drive the primary piston in the fluid intake direction and in a fluid discharge direction;
• An intake line leading from the vessel to the first pump chamber for drawing fluid from the vessel while the primary piston moves in the fluid intake direction:
• A discharge line leading from the first pump chamber to discharge fluid from the first pump chamber while the primary piston moves in the fluid discharge direction;
• and
• An intake line valve that prevents fluid from flowing from the first pump chamber back into the vessel while the primary piston is moving in the fluid discharge direction.