Patent ID: 8020587

Claim:
A hydraulic pressure accumulator, comprising: a vessel body, comprising a cylindrical vessel wall; a closeable fluid port positioned within one end of the vessel body, for communication with fluid sources external to the hydraulic pressure accumulator; a cylindrical nonpermeable sleeve, disposed within the vessel body and substantially concentric with the cylindrical vessel wall; a piston slidably disposed within the cylindrical nonpermeable sleeve, separating the interior of said sleeve into a first chamber, containing a gas adapted to be compressed under pressure, and a second chamber, containing pressurized fluid in fluid communication with the closeable fluid port and with an intervening volume containing fluid between the cylindrical nonpermeable sleeve and the cylindrical vessel wall; and a seal on one end of the piston positioned to engage an opposing surface in the event of a leak of pressurized fluid from the accumulator through the closeable fluid port, thereby preventing complete drainage of the pressurized fluid from the intervening volume through the closeable fluid port.