Gear Pump Analysis

A gear pump is a type of pump that displaces a volume of fluid by physical or mechanical action, or positive displacement pump. Power is applied to one of the gears and transmitted to a second driven gear via meshing teeth.

Fluid Flow

Contrary to popular opinion, fluid flow through a gear pump does not occur through the center of the meshed gears. In fact, fluid is carried from the inlet to the outlet side of the pump in the outside of each gear, in the gaps between the gear teeth.

Design

Gear pumps are simpler in design than other types of positive displacement pumps and have fewer moving parts. This means that they are typically more reliable, particularly in applications where operating pressures are low and overall operating efficiency is unimportant.

Noise

Simple, reliable and inexpensive though they are, gear pumps often create higher noise levels than other types of positive displacement pumps. The pumping mechanism creates pulsating flow, or flow ripple, that propagates through a hydraulic circuit, causing oscillation and audible noise.

References

• University of Missouri: The Theoretical Flow Ripple of an External Gear Pump
• "Root Cause Failure Analysis"; R. Keith Mobley; 1999