Patent ID: 7223080

Claim:
A double-acting, reciprocating piston, high-pressure, cryogenic pump comprising: a cylinder; a piston rod; a pair of spaced apart piston heads on said piston rod defining left side and right side pump chambers each having a suction valve communicating with a source of cryogenic suction liquid; each of said piston heads having a set of high-pressure seals; venting passageways for venting blow-by vapors or fluids between said piston seals; said venting passageways including a first generally radial venting passageway between said piston heads connected to a second axial venting passageway in said piston rod; said second axial passageway being in communication with said source of cryogenic suction liquid; said blow-by vapors or fluids mix and condense in said suction liquid; whereby said blow-by vapors or fluids are condensed in said suction liquid and do not interfere with normal operation of said cryogenic pump.