Reciprocating Pump With Screw Actuator

Abstract

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. lJpon 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.

1 . A reciprocating pump, comprising: 
 a stationary housing;    a travelling housing telescopically received within the stationary housing, the travelling housing being telescopically movable from a retracted position to an extended position;    a screw having a first end and an second end, the screw being housed within the stationary housing with the second end of the screw extending into the travelling housing, the screw being mounted for rotation about its longitudinal axis;    a motor adapted to supply rotational force to the screw;    a nut secured to the travelling housing, the nut engaging the screw, such that upon rotation of the screw in a first direction the nut travels toward the second end of the screw moving the travelling housing to the extended position extending past the screw, and upon rotation of the screw in a second direction the nut travels toward the first end of the screw moving the travelling housing to the retracted position; and    means for coupling a polish rod to the travelling housing in axial alignment with the screw, with the polish rod being raised and lowered by telescopic extension and retraction of the travelling housing.    
   
   
       2 . The reciprocating pump as defined in  claim 1 , wherein the screw is hollow, the polish rod extending up through the screw and being secured to the travelling housing by a clamp positioned at an upper end of the travelling housing.