Fluids are practically incompressible and cannot therefore
store pressure energy.
compressibility of a gas (nitrogen) is utilized in hydro-pneumatic
accumulators for storing fluids. HYDAC bladder
accumulators are designed on this principle, using nitrogen
as the compressible medium.
bladder accumulator consists of a fluid section and a
gas section, with the bladder acting as a gas-proof screen.
The fluid around the bladder is connected with the hydraulic
circuit, so that the bladder accumulator draws in fluid
when the pressure increases thus compressing the gas.
When the pressure drops, the compressed gas expands and
forces the stored fluid into the circuit.