Conveyor device for cryogenic liquids

The aggregate has a liquid-conveying piston pump provided for liquid gases, and a connector (11) provided in proximity of a lower dead center (12) of movement of a piston (3). The connector is releasable by movement of the piston and impinged with low pressure. A return line (8) with an overflow valve (10) is arranged between a supply line (4) that is guided from a supply tank into a suction chamber (1) of the pump, and a line (5) guided from the chamber to a pressure reservoir. A combination of pneumatic piston drives is provided with two pump heads to convey both hydrogen and oxygen.