These are the most common type of pump used in the gas and oil field. They are used to move large volumes of fluids at relatively low pressures. Centrifugal pumps work by using the centrifugal force created by a rotating impeller to move the fluid.
These pumps move fluids by trapping a specific volume of fluid and then forcing it out of the pump. Positive displacement pumps are typically used to move fluids that are abrasive or viscous.