RECIPROCATING PUMP WITH SCREW ACTUATOR

摘要

A reciprocating pump includes a stationary housing and a travelling housing. The travelling housing is telescopically received within the stationary housing and is movable from a retracted position to an extended position. A screw is provided having a lower end and an upper end. The screw is housed within the stationary housing, with the upper end of the screw extending into the travelling housing. A nut is secured to a lower end of the travelling housing. The nut engages the screw. Upon rotation of the screw in a first direction, the nut travels toward the upper end of the screw lifting the travelling housing to the extended position. Upon rotation of the screw in a second direction, the nut travels toward the lower end of the screw lowering the travelling housing to the retracted position. The polish rod is coupled to the travelling housing.