Patent ID: 7527074

Claim:
A hydraulic pressure accumulator, comprising: a rigid housing having an open interior; a first fixture mounted in said housing for fluid communication with a gas source exterior to said housing; a bladder, positioned within the interior of said housing and having an interior in communication with the first fixture and containing a mass of compressed gas; a second fixture mounted in said housing for fluid communication between a liquid source exterior to said housing and a space within the housing, said space defined between the housing and the bladder, an internal electrically conductive wire located within the bladder; and an electrically conductive contact element operably connected to the internal wire and protruding from the bladder toward the second fixture and configured to contact a second electrically conductive surface as the volume of liquid within the housing approaches a predetermined low level, thereby creating a circuit from the second electrically conductive surface to the internal wire and signaling the position of the bladder within the accumulator.