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Peristaltic pumps - an overview
Peristaltic pumps are the simplest possible pump, with no valves, seals or glands to clog or corrode. The fluid
contacts only the bore of a tube, eliminating the risk of the pump contaminating the fluid, or the fluid
contaminating the pump. Peristaltic pumps can operate dry without risk.
How they work
A compressible tube is squeezed between a roller and a track on an arc of a circle, creating a seal at the point
of contact. As the roller advances along the tube, the seal also advances. After the roller has passed, the
tube returns to its original shape, creating a partial vacuum which is filled by fluid drawn from the inlet port.
Before the roller reaches the end of the track, a second roller compresses the tube at the start of the track,
isolating a packet of fluid between the compression points. As the first roller leaves the track, the second
continues to advance, expelling the packet of fluid through the pump’s discharge port. At the same time, a
new partial vacuum is created behind the second roller into which more fluid is drawn from the inlet port.
Backflow and siphoning do not occur, and the pump effectively seals the tube when it is inactive. No valves
are needed.
The principle may be demonstrated by squeezing a soft tube between thumb and finger and sliding it along:
fluid is expelled from one end of the tube while more is drawn in at the other.
Animal digestive tracts function in a similar way.
Suitable applications
Peristaltic pumping is ideal for most fluids, including viscous, shear-sensitive, corrosive and abrasive fluids,
and those containing suspended solids. They are especially useful for pumping operations where hygiene is
important.
Peristaltic pumps operate on the positive displacement principle. They are particularly suitable for metering,
dosing and dispensing applications. Pumps are easy to install, simple to operate and inexpensive to maintain.
