Peristaltic pump working principle
Peristaltic pumps are a type of rotary positive displacement pump that are made up of two integral components; a rotor that has rollers or a “shoe” attached and a hose/tube. For this reason, this pump technology is also referred to as a peristaltic hose pump.
Roller operated peristaltic pumps
As the rotor turns, the attached rollers compress the tube where the fluid is contained, and it is that action that moves the liquid from the pump's inlet to its outlet. As less friction is generated by the rollers in comparison to shoe designs, such peristaltic pump models have:
- Lower power consumption, with up to 30% energy savings compared to shoe peristaltics
- Low starting torque - smoother operation and easier to adjust speed
- Easier hose maintenance as it doesn't require lubrication
Shoe operated peristaltic pumps
As the rotor turns, the attached shoe compresses the tube where the fluid contained, and it is this action that moves the liquid from the pump's inlet to its outlet. This version is ideal for more heavy duty, higher pressure requirements, where roller models can't efficiently handle the application.
Variety of fluids – As the only part of the peristaltic tube pump that comes into contact with the pumped liquid is the flexible inner tube, only the material of the tube/hose needs to be compatible with the fluid rather than also having to consider the o rings, seals and valves. This makes it a versatile solution for many fluids by changing the material of the inner hose:
- Natural Rubber (NR) - For water based fluids
- Neoprene (CR) - Good balance between chemical and mechanical resistance.
- Nitrile (NBR) – For fats, fuels and oils.
- EPDM – Ideal for hot fluids and clean in place applications, acids and alkaline.
- Silicon (VMQ) - Best for very high temperatures
Safe and clean operation – As the pumped liquid is kept contained within the inner hose, peristaltic pumps require no seal. The absence of a seal ensures that this pump type is less prone to leaking, making it an ideal solution for when handling corrosive liquids and dangerous chemicals.
Ideal for harsh and abrasive applications – As well as the above, peristaltic tube pumps are suited to heavy duty applications such as those involving viscous slurries and solids, as the fluid is only confined by the diameter of the inner tube. In addition, as there is no shearing motion applied by the pump, the design is also ideal for shear sensitive fluids.
Low maintenance – As the only wetted component of the peristaltic hose pump designed is the inner tube, wearing parts are limited to just this and it is consequently the only part of the pump that needs to be maintained. The absence of valves, seals and glands that come into contact with the pumped medium keep maintenance costs down.
Peristaltic pumps are a versatile design suitable for high and low flow performance, for both high and low viscosity fluids. This type of pumping technology is a popular choice for applications where other pump types fail to meet the requirements i.e. highly viscous or solid laden mediums. In addition, the wide variety of materials that the inner tube is available in, along with the peristaltic hose pump’s seal-less design, means that even aggressive chemicals can be handled.
Given the above design benefits, peristaltic tube pumps are ideal for the following (and many more!) applications:
- Food and drink manufacturing
- Sewage and sludge pumping
- Waste water and dewatering of excavations
- Oil sludge and waste oils
- Chemical dosing
- Paint, ink, pigment and dye
- Pulp and paper slurries