Pumping unit with dynamic fluid ballast

摘要

A pumping unit apparatus is provided for operating a well pump having sucker rod drive which is reciprocated from an uppermost position to a lowermost position, the apparatus having a base, a support structure mounted on the base, a member mounted on the support structure for pivotal movement about an axis and means connected to the member for pivoting said member between the two positions. Belting and pulley combinations mounted on the member and connected to the sucker rod provides rod string positioning to the rod string uppermost position when the member is on one position and a lower position when the member is in another position; a counterweight mounted on the member for movement with said member is provided wherein the counterweight is positioned relative to the axis so that the force of gravity acting on the counterweight applies a greater torque to the member when the rod string is in its uppermost position than is applied when the rod string is in its lowermost position. The counterweight being so positioned that a vertical line through the center of gravity of the shifting ballast counterweight moves toward and away from said axis as said member is pivoted.