What is peristaltic pumping

 

 

Ole Dich manufactured their first peristaltic pump in 1952, and we have specialised in peristaltic pumping ever since. We have a wide range of peristaltic pumps, fixed or variable speed, from 1 to 96 channels, flow rates from 2 yl/hour to 160 l/hour, controllable by hand, footswitch, timer or RS232 signal.

 

 

 

 

 

  

 

The drawing shows our 3 rollers pumphead loaded with tubing. The advancing roller occludes the tube which, as it recovers to its normal size, draws in fluid which is trapped by the next roller, (in the second part of the cycle) and expelled from the pump (in the third part of the cycle). This is the peristaltic pump system.

 

The rollers, rollertrack and tube together make the pump, and each part are equally important. The Ole Dich pumps provide flow rates from 2 yl/hour to 135l/hour, pressures up to 15 m water column, and a max. height of suction up to 6 m water column.

 

The flow rate depends mainly on the internal diameter of the tube and the speed at which the rollers advance. Suction lift capability depends on the restitutional power of the tube. If the tube does not restitute fully before the advance of the next roller, then the flow rate will be reduced.

 

For any particular flow rate, accuracy is maximised by using smaller bore tubing and a higher pump speed. For maximum tube life, however, it is best to use larger bore tubing and a slower pump speed.

 

For maximum flow rate, keep tube size and pump speed up, but keep suction lift to a minimum. For maximum suction lift or pressure performance use tubing with the greatest wall thickness available for the internal diameter chosen.

 

 

 

1 The pump does not contaminate the fluid.

2 The fluid does not contaminate the pump.

3 Peristaltic pumps are self-priming and can run dry.

4 The peristaltic pumping action is gentle.

 

There are infinity of laboratory processes where the ability to confine the fluid to a tube, and nothing else, is valuable. Instead of stripping and cleaning the pump, it is only necessary to fit a new pump tube which takes only minutes, or even seconds. A sterile tube creates a sterile pump.

 

Think of peristaltic pumps especially for fermentation, food processing, pharmaceuticals, beverage dispensing, inks and photographic solutions, as well as abrasive and aggressive fluids. If a fluid will pass through a tube, then a peristaltic pump can speed its flow, control its flow rate, or dispense it in precise volumes.

 

 

 

In practice, tube life depends not only on the tubing material, but on pump speed, fluid temperature, suction and pressure, as well as the chemical compatibility between the tube and fluid. For that reason, no guarantee of performance can ever be given, but the rules of thumb below will give guidance for most applications.

 

For long tube life, keep suction lift, pressure and temperature moderate, keep the pumphead speed low by using as large as possible bore, and as few rollers on the pumphead as possible.

 

Tube life will increase or decrease in proportion to pump speed. Halving pump speed or number of pressure rollers, will approxemately double the tube life. Also tube life is reduced by pumping into pressure. As a rule thumb, tube life is at least halved when pumping against 1 bar.