US Patent 7520129 Subsea pressure accumulator systems

An accumulator system which, in certain aspects, has a body with three (or more) interior chambers, e.g. in one aspect first, second, and third chambers, the body having a first body end with a first opening, and a second body end with a second opening, an amount of operational power fluid in the first chamber, an amount of pressurized gas in the second chamber for moving a piston assembly for moving power fluid from the body to operate an apparatus, the piston assembly having a cavity within a piston end for containing additional pressurized gas for moving the piston assembly.