Study on design and simulation analysis of the double horse-head pumping unit based on the compound balance structure

Abstract

Double horse-head pumping unit, being one of the most classical mechanical equipment, has high efficiency and good balance ability during the oil extraction owing to its horse-head structure connecting with the rod by the steel wire rope. But its characteristic of energy consumption reduction is limited because of the motor torque fluctuation and negative torque appearing while the pumping unit is working in the upstroke and downstroke. The compound balance design is applied to the double horse-head pumping unit by the crank balance and walking beam balance, which is completed by the equal energy principle during the up and down circulation of the oil suction unit. The finite element model of the whole equipment is built, and the simulation analysis is completed by the software ADAMS, under the conditions of the compound balance and that of the crank balance. The output torque of the crank, the forces from the back horse-head rope, and the connection pin are calculated. From the viewpoint of system design to compare with the traditional crank balance pumping unit, the compound balance design can reduce the torque fluctuation greatly, decrease the forces of steel wire rope connecting with the back horse-head, and get rid of the structure problems from the traditional pumping unit. The stress test of the double horse-head pumping unit designed by the compound balance method is completed in the oilfields. It has proved the correctness and reasonability of the compound balance design. The methodology of the compound balance design is helpful in improving the work efficiency and reliability and bringing about better abilities of energy consumption reduction for the pumping unit during its work circulation.