SELF-ALIGNING, FLUID-DRIVEN PUMPING UNIT

摘要

A reciprocating well pumping unit includes a fluid-driven cylinder to drive a reciprocating rod assembly. A valve controls fluid delivery to the cylinder, the valve having a valve spool capable of being positioned in a first position or a second position, the valve in the first position causing fluid flow that allows the lifting rod to extend, the valve in the second position causing fluid flow that allows the lifting rod to retract. A detent assembly provides resistance to movement of the valve spool between the second and first positions. A control rod is coupled to and moves with the lifting rod. A spring is capable of storing energy as the control rod is moved in the first direction and a rod stop engages the spring, the spring engaging the valve spool as energy is stored in the spring to urge the valve spool toward the first position.

主权项

1. A reciprocating well pumping unit comprising:
a fluid-driven cylinder adapted to be coupled to a reciprocating rod assembly, the cylinder having a lifting rod capable of traveling between an extended position and a retracted position; a valve capable of controlling fluid delivery to the cylinder, the valve having a valve spool capable of being positioned in a first position or a second position, the valve in the first position causing fluid flow that allows the lifting rod to extend, the valve in the second position causing fluid flow that allows the lifting rod to retract; a detent assembly providing resistance to movement of the valve spool between the second position and the first position; a control rod coupled to the lifting rod such that movement of the lifting rod in a first direction results in movement of the control rod in the first direction; a rod stop coupled to the control rod; and a spring carried on the control rod and capable of engagement with the rod stop, the spring capable of storing energy as the control rod is moved in the first direction and the rod stop engages the spring, the spring engaging the valve spool as energy is stored in the spring to urge the valve spool toward the first position.