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Positive Displacement Pumps

Consistent Flow, High-Pressure Handling & Industrial Applications

What Are Positive Displacement Pumps?

Positive displacement (PD) pumps move fluid by trapping a fixed volume and forcing it through the pump system. Unlike centrifugal pumps that rely on velocity, PD pumps deliver a steady, controlled flow regardless of system pressure—making them ideal for viscous, shear-sensitive, or high-pressure applications.

How Positive Displacement Pumps Work

PD pumps work by mechanically displacing fluid using a cavity (such as a chamber or rotor) and then pushing it through the discharge outlet. With each cycle or rotation, a consistent volume of fluid is moved.

There are two main categories:

Rotary Positive Displacement Pumps

These pumps use rotating components to move fluid.

  • Types:
  • Applications:
    • Viscous liquids (oils, syrups, resins)
    • Dosing and metering
    • Industrial processes requiring low pulsation

Reciprocating Positive Displacement Pumps

These pumps move fluid with a back-and-forth (reciprocating) motion.

  • Types:
  • Applications:
    • High-pressure spray systems
    • Chemical injection
    • Water jetting and cleaning

Key Features of Positive Displacement Pumps

  • Constant flow – Flow remains stable even with pressure fluctuations
  • Self-priming – Able to draw fluid into the pump without external priming
  • Handles viscous fluids – Ideal for thick, sticky, or semi-solid materials
  • Can run at low speeds – Reduces shear and wear, great for sensitive fluids
  • High-pressure capabilities – Reciprocating pumps are excellent for demanding pressure applications

Limitations of Positive Displacement Pumps

  • Requires pressure relief – Must have a bypass or relief valve to avoid over pressurising
  • Flow can be pulsed – Reciprocating types may require pulsation dampeners
  • More complex mechanically – Often requires more maintenance than centrifugal pumps
  • Sensitive to system blockages – Full system blockage can damage the pump

Applications of Positive Displacement Pumps

  • Mining & Slurry Transfer – Peristaltic and hose pumps for abrasive fluids
  • Chemical Dosing – Diaphragm and plunger pumps for precise injection
  • Food & Beverage – Lobe and peristaltic pumps for hygienic, shear-sensitive ingredients
  • Oil & Gas – Screw and gear pumps for hydrocarbons and viscous fluids
  • Water Treatment – Metering pumps for chemical dosing and flocculant injection
  • Pharmaceutical & Cosmetics – Sanitary PD pumps for controlled, repeatable flow

Summary: Is a Positive Displacement Pump Right for You?

Choose a positive displacement pump if your application requires:

  • Consistent flow, even under varying pressure
  • Handling of viscous, abrasive, or shear-sensitive fluids
  • Precise dosing or high-pressure performance

Choose the right type (rotary vs. reciprocating) based on:

  • Fluid viscosity and abrasiveness
  • Required flow rate and pressure
  • Clean-in-place or sanitary needs

Not sure which positive displacement pump suits your process?
Speak to our pump experts to discuss flow rates, fluid characteristics, and maintenance needs—we’ll help you select the ideal solution.