Piston pump for liquified gases

A piston pump for liquified gases has a piston capable of performing a reciprocating movement in a cylinder, which piston forms a suction chamber and a working chamber. A suction line closable by means of a non-return valve is assigned to the suction chamber, whilst a pressure line closable by means of a pressure valve is assigned to the working chamber. The piston has a bore on which a valve seat is arranged on the suction chamber side. A disc valve, the shaft of which is passed through the bore of the piston and is connected to a drive rod for the piston, which is assigned to a drive device, acts in concert with the valve seat. On the piston a stop is formed which, when the drive rod moves in the direction of the suction chamber and after the valve disc has lifted off from the valve seat, transmits the movement of the drive rod to the piston.