초록 ▼

A liquid cryogen pump in which liquid is maintained on both sides of the pump piston during operation. In the preferred embodiment, vapor, when present in the pump chamber, is passed from in front to behind the piston by providing a predetermined clearance between the piston and the cylinder in whic

A liquid cryogen pump in which liquid is maintained on both sides of the pump piston during operation. In the preferred embodiment, vapor, when present in the pump chamber, is passed from in front to behind the piston by providing a predetermined clearance between the piston and the cylinder in which it is reciprocated. The clearance is preferably large enough to pass enough liquid cryogen to maintain the desired head of liquid behind the piston. In the embodiment set forth, the pump is arranged so that it can be immersed in the liquid cryogen to be pumped with its pumping chamber and valves at or close to the bottom of the liquid cryogen supply. Heat transfer between the warm, upper end of the pump and its cold end is effectively restricted, and, preferably, the warm end is connected to the cold end of the pump by thin-walled tubular members formed of low thermal conductive materials to minimize heat transfer by conduction.

대표청구항 ▼

A pump for compressing and transferring a cryogenic liquid which is in a container, the pump when mounted vertically comprising a closed tubular member mounted vertically inside said container, a piston mounted for vertical reciprocal movement in said tubular member, motive means for reciprocating s

A pump for compressing and transferring a cryogenic liquid which is in a container, the pump when mounted vertically comprising a closed tubular member mounted vertically inside said container, a piston mounted for vertical reciprocal movement in said tubular member, motive means for reciprocating said piston, inlet means for the passage of liquid from said container to a variable volume pumping chamber in said tubular member below said piston during the upward stroke of the piston, outlet means for the passage of liquid from said pumping chamber during the downward stroke of said piston, means spacing said piston from the inside wall of the tubular member by a predetermined clearance, said clearance being large enough for vapor in said pumping chamber to be forced through the clearance into the space above the piston enclosed by the tubular member during the downward stroke of the piston, liquid supply and control means for maintaining a supply of said liquid in the space above the piston large enough to prevent vapor from flowing through said clearance into said pumping chamber from above the piston, and pressure control means for maintaining said liquid supply in the space above said piston at a pressure substantially less than the pressure of the liquid in said pumping chamber during the downward stroke of said piston.