Gerotor Pump

A gerotor pump is a specific type of internal gear pump in which the pump action is created by two gears — an inner driving rotor and a slightly larger outer driven rotor — but without a crescent-shaped partition. The gears rotate with an offset between their centers so that the space between their teeth expands at the inlet (drawing fluid in) and contracts at the outlet (pushing fluid out), creating a continuous, smooth flow.

1. What is a gerotor pump?
It’s a rotary positive displacement pump that uses a gear-within-a-gear arrangement (a smaller inner rotor and a larger outer rotor), with the outer rotor having one more tooth, and no crescent, to move liquid through expanding and contracting cavities.

2. How does a gerotor pump work?
Liquid enters the spaces between the inner and outer gears as the cavities expand on the suction side. As the gears continue to rotate, these cavities travel around the pump and then contract on the discharge side, forcing the liquid out. The tight gear clearances prevent fluid from returning to the suction side.

3. What are gerotor pumps used for?
Gerotor pumps are efficient, compact, and operate quietly with few moving parts, making them suitable for a wide range of applications including hot oil filtration and automotive fluids such as fuels, lubricating oils, and transmission fluids.