Sucker Rod Pump - PumpJack

The Rod Pump is a traditional form of artificial lift. It is the most familiar  as a symbol of oil production, having been in use throughout the world since the pioneer oil industry days.
Rod Pumps / Pump Jacks still capture a significant percentage of the artifical lift technology utilized by oil producers.

How a Rod Pump works:

1. A motor supplies power to a gear box. The gearbox reduces the angular velocity and increases the torque relative to this input.
2. As shown above left, the crank turns counterclockwise and lifts the counterweight. Since the crank is connected to the walking beam via the pitman arm, the beam pivots and submerges the plunger. The illustration shows the horsehead at its lowest position. This marks the end of the down stroke. Note that the crank and the pitman arm are in-line at this position.
3. The upstroke raises the horsehead and the plunger, along with the fluid being pumped. The upstroke begins at the point shown. At the end of the upstroke, all joints are in-line. This geometric constraint determines the length of the pitman arn.
4. The embodiments (top right) show the plunger and ball valves in more detail. These valves are opened by fluid flow alone. On the upstroke, the riding valve is closed and the standing valve is open. Fluid above and within the plunger is lifted out of the casing while more fluid is pumped into the well. On the down stroke, the riding valve is opened and the standing valve is closed. Fluid flows into the plunger and no fluid is allowed to leave the well.