Peristaltic pumps - how do they work?

Learn more about the benefits of switching to a Watson-Marlow peristaltic pump

Peristaltic pumps, or tube pumps are a type of positive displacement pump. The pumps use the principle of peristalsis as the basis for their design. Peristalsis, in a biological sense, is a series of muscle contractions that moves food to different parts along the digestive system.

How do peristaltic pumps work?

Rollers or shoes in a peristaltic pump compress the tube or hose as they rotate, creating a vacuum which draws fluid through the tube.

Nothing but the pump tube or hose touches the fluid, eliminating the risk of the pump contaminating the fluid, or the fluid contaminating the pump. The animation shows fluid being drawn into a pump tube, trapped by the pumphead roller, and expelled when the next roller passes over the tube. As the rollers rotate, a vacuum is formed in the tube, pulling in more fluid, for the next roller pass.

The complete closure of the tube when is it occluded (squeezed) between the roller and the track, gives the pump its positive displacement action, preventing backflow and eliminating the need for check-valves when the pump is not running.

What are the advantages of using peristaltic?

The main advantage of peristaltic pumps is that nothing but the tube touches the fluid.  Because only the inner bore of the tube touches the fluid, they eliminate the risk of the pump contaminating the fluid, or the fluid contaminating the pump.

How does a peristaltic pump work?

 

The animation shows fluid being drawn into a pump tube, trapped by the pumphead roller, and expelled when the next roller passes over the tube. As the rollers rotate, a vacuum is formed in the tube, pulling in more fluid, for the next roller pass.

The complete closure of the tube when is it occluded (squeezed) between the roller and the track, gives the pump its positive displacement action, preventing backflow and eliminating the need for check-valves when the pump is not running.

Key Products

  2. 530 process pumps

    530 process pumps

    Flow rates to 3.5 L/min (55 USGPH) and pressures up to 7 bar (100 psi). Precise 2,200:1 speed control range.

    Pumps - cased pumps

  3. APEX hose pumps

    APEX hose pumps

    Flow rates to 6,200 L/h (27.3 USGPM) and pressures up to 8 bar (116 psi). Optimised for process uptime.

    Pumps - hose pumps

  4. Bredel hose pumps (10-50)

    Bredel hose pumps (10-50)

    Flow rates to 17,520 L/h (4,623 USGPH) and pressures up to 16 bar (232 psi). Eliminate ancillary equipment.

    Pumps - hose pumps

Why choose a Watson-Marlow peristaltic pump?

  • Easy to install, simple to operate and inexpensive to maintain
  • Scalable technology to meet a variety of processing needs
  • Low shear, gentle handling without impellors, vanes, lobes or valves in the fluid path
  • Delivers flow stability and metering accuracy
  • The only replacement part is the low cost tube, which can quickly be replaced in-situ

 

Easy-to-use

Ease of operation comes from simple tube loading.

In applications where a disposable tube set is required, the tube must be replaced once per procedure, which could occur several times each day depending upon your specific process or application. It is critical that tube changeover is done correctly to avoid compromising pump performance. 

For example, Watson-Marlow LoadSure technology offers snap-fit one minute maintenance.

No valves or seals

A peristaltic pump requires no valves in its operation because at least one roller is always compressing the tube against the track, preventing backflow or siphoning when the pump stops.

Accurate repeatable flow rates

Because peristaltic pumps are positive displacement pumps moving a fixed volume for each revolution, flow rates are linearly proportional to speed over the pumps recommended speed range.

When calibrated to account for system losses, a peristaltic pump can achieve metering and dosing accuracy of ±0.5%.

For example, delivering flow rates that remain constant right up to 7 bar Qdos peristaltic chemical metering pumps give users a unique advantage over diaphragm metering pumps.

Self-priming and dry-running

Peristaltic pumps need no priming and can run dry without damage. 

For example, our Bredel peristaltic hose pumps are dry running and self-priming with no ancillary equipment, check valves, sealing water flush systems or run-dry protection required.

Pulsation control

With most positive displacement pumps that deliver a fixed volume per pump stroke or revolution, pulsation or pressure drop can be observed.

For example, our Quantum single-use pumps deliver flow linearity throughout the 3 bar single-use processing pressure range up to 20 L/min, leading the market with virtually no pulsation.

No pump or fluid contamination

With a peristaltic pump, the only wetted part is the tubing. In sanitary medical applications, the pump will not contaminate a sterile fluid in the tube, and the pump will not require cleaning. In most medical applications, the tube is the part of a disposable tube-set that is connected to other components such as a catheter.

As a total solution provider, did you know we also supply solutions to help complete your fluid path including our BioPure fluid path components and Aflex PTFE hoses.

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