Cryogenic fluid delivery system

A pump for transferring cryogenic fluid from a storage tank comprising:

• a. a pumping cylinder housing defining a pumping cylinder, said pumping cylinder having an inlet adapted to communicate with said storage tank, an outlet and a pumping piston slidingly positioned therein so that cryogenic liquid from the storage tank is pumped through the pumping cylinder outlet by motion of the pumping piston;
• b. an actuating cylinder housing defining an actuating cylinder, said actuating cylinder having an inlet, an outlet and an actuating piston slidingly positioned therein, said actuating piston joined to said pumping piston by a connecting rod;
• and
• c. a heat exchanger in circuit between the pumping cylinder outlet and the actuating cylinder inlet, said heat exchanger vaporizing a portion of pumped cryogenic liquid so that said actuating piston is propelled by the resulting cryogenic vapor and said pumping piston is moved by the connecting rod.

A method for transferring a cryogenic liquid from a storage tank to a use device comprising the steps of:

• a. providing a cryogenic liquid pump that operates on cryogenic vapor;
• b. connecting the storage tank and use device to the cryogenic liquid pump;
• c. pumping cryogenic liquid from the storage tank;
• d. directing a portion of the pumped cryogenic liquid to the use device;
• e. vaporizing a remaining portion of the pumped cryogenic liquid that was not directed to the use device;
• and
• f. directing the cryogenic vapor to the pump so that the pump is powered by the cryogenic vapor.