Analysis and assessment on performance of beam pumping units with guide bar mechanism

For analysis and assessment on performance of a state-of-art pumping units with guide bar mechanism, analytic methods were provided in this paper for analyzing their movements and kinetic features. Depending on the dimension of the prototype, movements and kinetic features of suspension points in the pumping units, together with stresses on major components and torques of the gear box were determined. The results show that the pumping units have relatively high crank angles between extreme positions. Velocities of suspension point during upward stroke can be seen as constant approximately. These movements may contribute to energy conservation in certain indicator diagrams. However, movements in upward and downward strokes displayed poor smoothness. Consequently, beams may be deployed to balance the system. Crank may produce significant stresses with alternating directions on the beam. The pumping units with this structure can effectively satisfy demands of miniature pumping units with low strokes in oilfields.