A hydro-pneumatic accumulator is a device used specifically for storage of liquid under pressure. As liquids, for all practical purposes, are incompressible, this objective is achieved by utilizing the compressibility of gases. A flexible rubber separator i.e., diaphragm is fitted into the accumulator shell. An inert gas - nitrogen - is filled into the diaphragm through a pressure valve to a pressure. The diaphragm expands, filling the entire volume of the accumulator shell. When the system (circuit) pressure is higher than the gas precharge pressure, the liquid enters the shell and the diaphragm is compressed reducing the gas volume. Should the liquid pressure rise, the volume of gas reduces with an attendant rise in pressure, thus balancing the Liquid pressure. A potential energy is now stored in the accumulator to be utilized whenever needed.