STRAIN TEST AND STRENGTH ANALYSIS FOR FRAMEWORK OF PUMPING UNIT IN FIELD

The stresses of different type framework of optimized pumping unit were tested and analyzed by using strain-bridge test method in model area. The result showed that the stress of framework of variable-diameter wheel pumping unit was largest, stress difference between front leg and back leg of framework was also largest; that of double donkey heads pumping unit was larger, the stress difference of that was smaller; that of swing-rod pumping unit was smaller and the stress difference of that is small; that of normal beam pumping unit is smallest and the stress difference of that is also smallest.The strength safety coefficient of other framework of pumping unit except that of variable-diameter wheel pumping unit was bigger. Crank groove wear of swing-rod pumping unit was very seriously.