Mechanical oil recovery is the basic means to extract crude oil from underground in China and many countries in the world. At present, the beam pumping unit is widely used, as shown in Figure 3-80, and it is also used in some areas, as shown in Figure 3-8 1. The working principle of beam pumping unit is that the motor drives the crank 8 to rotate through the deceleration of pulley and reducer, and a counterweight is installed on the crank to balance the load borne by the motor in the up-and-down stroke of pumping unit. The crank drives the connecting rod to do plane motion, drives the walking beam to swing around the bracket, and the rope hanger on the donkey head pulls the sucker rod to move up and down, driving the piston in the underground oil pump to suck crude oil and discharge it to the ground.
Fig. 3-80 Conventional beam pumping unit 1- braking device; 2- motor; 3- reducer pulley; 4- gearbox; 5— Input shaft; 6— Intermediate shaft; 7— output shaft; 8— Crank; 9— Connecting rod shaft; 10- brackets; 1 1- balance weight; 12- connecting rod; 13-beam axis; 14 beam; 15- balance plate; 16-walking beam; 17- brackets; 18- donkey head; 19- rope hanger; 20— Wellhead sealing box; 2 1- oil outlet tee; 22— Chassis
Fig. 3-8 1 schematic diagram of beam-less pumping unit mechanism 1 crank; 2- steel cable; 3 pulleys; 4- Balance weight