What is a Pumping Unit? A pumping unit is a mechanical device used to lift liquid (usually crude oil) from underground wells when the natural pressure isn't sufficient. It converts rotary motion from a motor or engine into the reciprocating (up-and-down) motion needed to drive a sucker rod and pump assembly deep underground. The classic nodding movement is created by a counterweighted walking beam. | Chemical Engineering, Prof.Dr. Ahmed Faiq Al-Alawy