One of the main tasks of hydraulic accumulators is, for example, to absorb a certain volume of a pressurized fluid from a hydraulic system and return it to the system when required.

Because the fluid is pressurized, hydraulic accumulators are regarded as pressure vessels and must be rated for the maximum operating pressure taking account of acceptance standards valid in the country of installation.

In most of the hydraulic systems, hydropneumatic (gascharged) accumulators with separating element are used.

Depending on the design of the separating element, we distinguish between bladder-type, piston and diaphragm-type accumulators.

Hydraulic accumulators basically consist of a fluid and a gas section with a gas-tight separating element. The fluid section is connected with the hydraulic circuit. As the pressure rises, the gas is compressed and fluid gets into the hydraulic accumulator. As the pressure falls, the compressed gas expands and displaces the accumulated fluid into the circuit.