Piston accumulator

A piston accumulator, comprising:

• an accumulator housing having a gas side and a liquid side in the accumulator housing;
• a separating piston being guided for longitudinal motion in the accumulator housing and separating the liquid side from the gas side;
• and
• a return device in the separating piston being capable of at least partially returning transitioned liquid transitioned from the liquid side to the gas side despite a piston seal on the separating piston back to the liquid side, the return device including a control piston movably guided in the separating piston, the control piston having an inner chamber being inside the control piston and being fillable with the transitioned liquid, the control piston being movable into an open position by the action of an energy storage device, in the open position the inner chamber is connected in fluid communication to the liquid side via a non-return valve blocking fluid flow in a direction of the gas side, the control piston being movable into a blocking position in which a closing element located on the control piston blocks fluid communication between the inner chamber and the liquid side upon the control piston contacting an end cover of the accumulator housing and being fully retracted.