Accumulator

A component in a hydraulic system that allows a noncompressible fluid, such as oil, to be stored under pressure. An accumulator has two compartments separated by a flexible or movable partition such as a diaphragm, bladder, or piston. One compartment contains compressed air or nitrogen, and the other is connected into the source of hydraulic pressure. When oil is pumped into the accumulator, the partition moves over and increases the pressure of the air. This air pushing against the partition holds pressure on the oil. An accumulator in an aircraft hydraulic system acts as a shock absorber and provides a source of additional hydraulic power when heavy demands are placed on the system.