The Study Of Transforming The Beam-pumping Unit Into The Compound-balanced Pumping Unit With An Auxiliary Crank On Connecting Rod

The conventional beam pumping unit has a significant role in oil field with simple structure,high reliability,convenient maintenance,and adapting to working conditions on site.However,the structure characteristic of the conventional beam pumping unit determines that its balance effect is poor,crank torque is ripple,there is negative torque,large energy consumption,low working efficiency and so on.Such as in Daqing oil field,there was more than 48000 well by the year 2008,the beam pumping unit accounted for 80%,but the average efficiency of beam pumping unit is only 25%,most of the electrical energy was wasted.Thus improving the efficiency of conventional beam pumping unit has great practical significance.Set up the pumping unit motion analytical basic model.Analysis the kinematics of suspension point,the torque of reducer output shaft and the power saving rate.Set up transforming beam-pumping unit's virtual prototype.Kinematics and dynamics simulation analysis is carried out on the virtual prototype.After the balance,the torque amplitude of reducer output shaft is reduced and eliminated the negative torque.According root-mean-square torque,when the large crank phase angle is 8 degree,the power saving rate is 2.83%;when the large crank phase angle is 16 degree,the power saving rate is 9.17%;when the large crank phase angle is 24 degree,the power saving rate is 9.93%.The key parts' intensity of the unit is checked.Because of the connecting rod intensity can't meet the requirements in the early days,design new connecting rod in truss structure.Due to the big crank shaft rotating,design double crank structure.Key parts such as connecting rod,crank shaft and bracket can meet the intensity requirements after transforming.Transform a beam pumping unit in the oil-field and carry on comparison test before and after the transforming.The test indicates that the motor eliminates the negative torque,the torque amplitude,the active power and the power consumption per ton liquid per hundred meters drops markedly.The transforming machine has run 8 months safely,and there are no questions on intensity.