Positive Displacement Pumps

Positive displacement (PD) pumps move fluid by trapping a fixed volume and forcing it into a discharge pipe. Unlike centrifugal pumps, they deliver nearly constant flow regardless of discharge pressure.

Types of Positive Displacement Pumps

Gear Pumps

External Gear Pumps

• Two meshing gears rotate in opposite directions
• Fluid trapped between gear teeth and casing
• Simple, reliable, good for clean, viscous fluids
• Flow proportional to speed
• Typical efficiency: 80-95%