Cryogenic pump

Abstract

A method for pumping a cryogenic liquid with a pump having a piston, an intermediate fluid seal, and a pumped fluid seal, wherein the piston is slidably positioned within a cylinder so that the piston defines, at least in part, an intermediate fluid chamber and a fluid pumping chamber, and a differential pressure space is defined between the intermediate fluid seal and the pumped fluid seal. The method comprises actuating the piston by cyclically directing an intermediate fluid to the intermediate fluid chamber of the pump so that the cryogenic liquid is received and pumped by the fluid pumping chamber of the pump. Additionally, the method detects a pressure in the differential pressure space and vents the differential pressure space when the detected pressure of the differential pressure space reaches a first predetermined pressure level that is below a pressure of the intermediate fluid in the intermediate fluid chamber.

Dependencies are inferred from the claim text.