Hydraulic accumulator with a free-moving piston as a separator between gas and hydraulic fluid (Figure K 19). Since there is no separating wall made of rubber, the fatigue resistance is greater than for diaphragm accumulators. In addition, the entire cylinder volume can be used for oil, with any number of gas bottles being connected downstream. Weak points are the seal inside the piston and the weight of the piston in terms of fast removals.
Figure K 19: Piston type accumulator