How Does a Peristaltic Pump Work? The Working Principle
To understand how a peristaltic pump works, it is best to think of the human digestive tract, specifically the throat. Peristalsis is a series of muscle contractions and relaxations that moves food along. A peristaltic pump mimics this natural process using a rotor with rollers or shoes to compress a flexible hose or tube.
The Three Phases of the Pumping Cycle
The operation of a peristaltic pump can be broken down into three distinct phases that repeat continuously:
1. Suction (Induction)
As the rotor turns, the rollers or shoes pass over the hose, pressing it completely flat. Once the roller passes, the hose’s elasticity causes it to "spring back" to its original shape. This expansion creates a powerful vacuum that draws the liquid into the hose.
2. Transport
The liquid is trapped in a "pocket" between the rollers. Because the hose is pinched shut at both the front and back of this pocket, the fluid cannot escape. The rotor pushes this pocket of liquid forward through the pump head.
3. Discharge (Expulsion)
When the roller reaches the end of the pump housing, the occlusion ends. The final roller pushes the liquid out of the discharge side of the pump and into the piping system.
Technical Features: Occlusion & Precision
The term occlusion refers to how much the roller compresses the hose.
● Complete Occlusion: The hose is pressed 100% flat, preventing any backflow or "slip". This makes the pump a true positive displacement pump, ideal for precise dosing.
● Seal-less Design: Because the hose itself acts as the seal, there are no mechanical seals or valves that can leak or clog.
Why the Peristaltic Principle is Unique
The mechanical design offers several technical advantages over other pump types:
● No Cross-Contamination: The liquid only ever touches the inside of the hose or tube. It never comes into contact with the rotor, rollers, or the external environment.
● Dry Running & Priming: Because the pump is capable of creating a strong vacuum through hose restitution, it is naturally self-priming and can run dry without any damage to the internal components.
● Gentle Action: The compression is a "low-shear" process, meaning it does not damage fragile particles or sensitive fluids.
● Solid Handling: The pump can easily move fluids containing large solids or abrasive slurries because there are no internal valves to get stuck.
Important Components: The Hose and Tube
The performance of the pump is largely determined by the hose or tube. Since this is the only part in contact with the fluid, it must be carefully selected based on:
● Material Compatibility: Different materials (like NBR, EPDM, or Silicone) are used depending on whether the fluid is acidic, oily, or food-grade.
● Reinforcement: Industrial hose pumps (like the Verderflex Dura) use reinforced hoses to handle higher pressures, while tube pumps use softer tubes for precision at lower pressures.
Ready to see this in action?
Watch our detailed animation to see how the rollers and hose work together to provide a seamless flow.
Find the Right Pump for Your System
Now that you understand the mechanical principle, you can explore which of our pump series best fits your flow and pressure requirements.