... SY/T5044 beam pumping unit, and the American Petroleum Institute API 11E standard ,the tecnology is mature .1).The overall struture ... as to reduce the stroke frequency for exploitation ,pumping unitType API spec 11ERated suspension center loadReducer TorqueStroke Stroke FrequencyMotor Power Machine ... -192140734.8,4.2,3.65,7,95531.7 oil api pumping unit