Membrane Accumulators are used as partition between the fluid side and the gas side of the accumulator. Membrane accumulators are produced in large quantities and are well-suited for relatively simple/cheap hydraulic systems. A membrane accumulator is made of 2 strong steel halves that are welded together. The U-formed membrane separates the gas from the hydraulic fluid. Membranes are available in nitrile rubber NBR, epichlorhydrin ECO and nitrile rubber suitable for low temperatures (-40° C). When pre-filled a robust steel knob seals off the hole at the fluid side and this prevents the membrane from being pushed out of the accumulator.