Subsea pressure accumulator systems

An accumulator system, the accumulator system for subwater use, the accumulator system comprising

• a body,
• a fluid chamber within the body for selectively containing power fluid,
• a piston assembly movably disposed within the body,
• a gas chamber within the body for containing gas under pressure to move the piston assembly to move the power fluid out of the fluid chamber of the body,
• the piston assembly including a cavity therein for containing gas under pressure for assisting in movement of the piston assembly,
• the cavity in fluid communication with the gas chamber, and
• at least one insert removably located within the cavity for reducing the gas-containing capacity of the cavity.

An accumulator system, the accumulator system for subwater use, the accumulator system comprising

• a body,
• a fluid chamber within the body for selectively containing power fluid,
• a piston assembly movably disposed within the body,
• a gas chamber within the body for containing gas under pressure to move the piston assembly to move the power fluid out of the fluid chamber of the body,
• the piston assembly including a cavity therein for containing gas under pressure for assisting in movement of the piston assembly,
• the cavity in fluid communication with the gas chamber,
• the body having a third chamber,
• the body having a first body end with a first opening in the body, and a second body end with a second opening in the body,
• an amount of operational power fluid in the fluid chamber,
• an amount of pressurized gas in the gas chamber,
• a lower pressure in the third chamber,
• the piston assembly movably and sealingly mounted within the body, in the piston assembly a first piston end closing off the first opening and preventing hydraulic fluid from exiting through the first opening from the first chamber, the first piston end having an outer surface and an inner surface, the operational power fluid applying a first pressure against the first piston end's inner surface, water exterior to the accumulator system to contact and to apply pressure to the outer surface of the first piston end to move the piston assembly in a direction toward the second body end,
• a piston rod with a first rod end and a second rod end, the first rod end connected to the first piston end, the second rod end connected to the second piston end,
• the piston assembly having a second piston end movably located in the second chamber, the second rod end connected to the second piston end, gas in the second chamber able to act on the second piston end to move the piston assembly in a direction away from the first opening, and
• a channel through the piston rod and in fluid communication with the cavity and with the second chamber so that the gas within the cavity is flowable into the second chamber.