A gear pump is a hydraulic pump that consists of gears that mesh together in various manners to create fluid flow.Source : <a href="http://www.go2atp.com/RG_Demo/FPSRG/PPT/FPS04.ppsFire">http://www.go2atp.com/RG_Demo/FPSRG/PPT/FPS04.ppsFire</a> Pump Theory - STAMFORD FIRE DEPARTMENT PPTPresentation Summary : Fire Pump Theory Pump Types Section 180 Class #2 Background of fire pumps Positive Displacement Pumps Rotary Vane Pump Rotary Gear Pump Piston Pumps Single /