Bladder accumulators are used for energy storage, shock and vibration absorption, and leakage oil compensation or volume compensation in hydraulic systems.
They consist of a seamless pressure vessel (high-tensile steel) the interior of which is split into a gas and a fluid side by an elastic bladder. When the operating pressure is increased, hydraulic fluid flows into the accumulator and compresses the gas in the bladder until the gas pressure is identical to the fluid pressure. When the operating pressure is reduced, the gas expands again and feeds the hydraulic system with hydraulic fluid.