CRYOGENIC PUMP FOR LIQUEFIED NATURAL GAS

摘要

A cryogenic pump (110) for pumping liquefied natural gas (lng) from a cryogenic tank (104) storing lng includes a drive assembly (114) and a pump assembly (112) disposed along a pump axis (118). The drive assembly (114) includes a spool housing (150) having a plurality of spool valves (180) arranged around the pump axis (118), a tappet housing (152) having a plurality of tappet bores (200) with slidable tappets (156) around the pump axis (118), and spring housing (154) including a plurality of movably disposed pushrod (158) urged upward by a plurality of associated pushrod springs (230). Hydraulic fluid received by a hydraulic fluid inlet (170) in the drive assembly (114) is directed by the spool valves (180) to the tappet bores (200) to move the tappets (156) downward against the pushrods (158). To collect the hydraulic fluid, the lowermost spring housing (154) also includes a collection cavity (220) formed therein that can return the hydraulic fluid to a hydraulic fluid outlet (172).