In this pump, fluid is contained within a flexible tube fitted inside a circular pump casing. This pump is a positive displacement pump and is very useful for a wide range of fluids.
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Working
In a peristalsis pump, a rotor with a number of “rollers”, “shoes”, “wipers”, or “lobes” attached to the external circumference of the rotor compresses the flexible tube. As the rotor turns, the fluid moves through the tube due to the compression force that acts due to the rotor. As the tube regains its original shape due to flexibility fluid flow is induced to the pump. This process is called peristalsis and is used in many biological systems such as the gastrointestinal tract.
Typically, there will be two or more rollers, or wipers, occluding the tube, trapping between them a body of fluid. The body of fluid is then transported, at ambient pressure, toward the pump outlet. Peristaltic pumps may run continuously, or they may be indexed through partial revolutions to deliver smaller amounts of fluid.
Limitations
- The flexible tubing will tend to degrade with time and require periodic replacement.
- The flow is pulsed, particularly at low rotational speeds. Therefore, these pumps are less suitable where a smooth consistent flow is required. An alternative type of positive displacement pump should then be considered.
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Applications
- Dialysis machines
- Open-heart bypass pump machines
- Medical infusion pumps
- Carbon monoxide monitors
- ‘Sapsucker’ pumps to extract maple tree sap
- Liquid food fountains
- Beverage dispensing
- Food-service Washing Machine fluid pump
- Printing, paint, and pigments
- Pharmaceutical production
- Dosing systems for dishwasher and laundry chemicals
- Concrete pump
- Pulp and paper plants
- Minimum quantity lubrication
- Chemical treatment in water purification plant
- Sewage sludge
- Aquariums, particularly calcium reactors