Peristaltic pumps are self-priming, positive displacement pumps that are able to deliver relatively high pressure, pass solids and transport corrosive and abrasive media. It is of high importance to select the right pump for the application to achieve the best performance.
Peristaltic pumps can be seperated into two types: low pressure, low flow pumps intended for use in laboratories or for low flow dosing or metering applications; and industrial class pumps. The industrial units are bigger, handling higher flows and able to generate higher pressures.
The peristaltic pump is quite easy to install and is inexpensive to maintain if selected correctly.
While selecting a peristaltic pump it is important to consider parameters such as duty cycle; flow; pressure; suction conditions; the correct hose (tube) for the pumped media; temperature limitations; cleaning requirements (CIP or SIP); the effect of possible contamination; and maintenance aspects.
Duty cycle
If the pump is expected to operate on a continuous basis, the speed needs to be reduced in order to prevent a shortened hose life. Manufacturers have performance curves that detail what part of the pump curve can be treated as continuous duty and what part should only be used as intermittent.
Flow
Performance curves are based mostly based on water-like substances and flooded suction. When dealing with more viscous fluids or high suction lifts, this will need to be factored into sizing the pump for the correct flow inclusive of de-rating speeds for these aspects. Good manufacturers will have de-rating charts for increased viscosity.
Pressure
Peristaltic pumps can be applied on applications with pressures to 15 bar. Manufacturers can provide details on what models are rated to certain pressures and what the flow and speed limitations are.
Suction conditions
Peristaltic pumps are capable of high suction lifts, but any peristaltic pump selected for a duty requiring a suction lift should have a pulsation dampener fitted. If the viscosity exceeds 2000cPs, the suction line diameter should be increased. It is always recommended to keep the suction line as short as possible.
Correct hose
For an extended hose life it is crucial to select the hose material meeting the application requirements. If to be used in food or pharmaceutical products hygiene is also a requirement.
Natural isoprene for abrasive fluids or moderately aggressive fluids: this is the most common hose material and is often available with various pressure ratings.
Natural isoprene with substrate for food products: these hoses have FDA approval numbers and are suitable for the transportation of food grade products. Should be able to sterilise with hot water and a diluted cleaning agent and also steam cleaning.
EPDM: suitable for a wide range of chemicals.
NBR: suitable for oils, greases, hydrocarbons and various solvents.
NBR for food products: these hoses will also have FDA approval numbers and are suitable for oils and fats. Should be able to sterilise with hot water and a diluted cleaning agent and also steam cleaning.
Hypalon: suitable for a range of concentrated acids and alkaline liquids.
Temperature limitations
Manufacturers provide temperature limitations in their hose selection guides. In this way it is ensured that operating temperatures do not exceed the temperature rating of the hose.
Cleaning requirements
In hygienic application hoses need to be cleaned in place (CIP) or sterilised in place (SIP).
Contamination
Selecting a peristaltic pump with rollers instead of shoes is best. The pumps with shoes will need their casings to be full of lubricating fluid. When the hose starts to fail, the lubricating fluid may contaminate the product being pumped.
Maintenance
A peristaltic pump does not need a lot of Maintenance. The hose is the only part that needs to be maintained.
Early leak detection is an important feature that reduces maintenance costs and is only possible and only possible for pumps with the roller on bearing design. Because casings are not filled with fluid, a simple “designed leak detector can pick up hose failures early, minimising product loss and mess.
A remotely operated retractable roller will also reduce maintenance costs by extending hose life.
Metrans Makina is the authorized distributor of Bredel peristaltic pumps in Turkey. Pleas contact for further information and requests.