... Petroleum Institute API 11E standard ,the tecnology is mature .1).The overall struture is reasonable,steady work ,small noise ... tooth gear,high-precision machining ,large carrying capacity ,long lifetime .pumping unit1.Walking beam compound balaned pumping units ... 2.8HY25-64-30302.80.759,143.24.5CYJ3-1.2-2.8HY25-64-48302.81.26,9, ... 124.05.2CYJ3-1.5-4.5HY40-64-60304.51.59,144. ...