The Basics of a Peristaltic Pump

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Peristaltic Pump DiagramVeloDyne Systems uses various brands of pumps on our chemical feed systems, liquid polymer systems, lime slurry systems, and liquid chemical feed skids. With more than 25 years of experience we have used our fair share of manufactures and pump types, since we are not tied to a certain manufacture it gives us the ability to provide the pump on our systems that the customer is looking for. We often use peristaltic pumps on our systems some being hose pumps and others being tube pumps.

A peristaltic pump is a type of positive displacement pump used for pumping a variety of fluids. The fluid is contained within a flexible tube or hose fitted inside a circular casing and now linear designs have been brought to market within the last few years. A rotor with a number of rollers, shoes or lobes attached compresses the flexible hose or tube. As the rotor turns, the part of the tube under compression is pinched closed or "occludes" thus forcing the fluid to move through the tube. Additionally, as the tube opens to after the passing of the cam "restitution” fluid flow is induced to the pump. This process is called peristalsis (to get the name Peristaltic”) and is used in many biological systems. Typically, there will be two or more rollers, or shoes, occluding the tube, trapping between them a body of fluid. Peristaltic pumps may run continuously, or they may be calibrated for  partial revolutions to deliver lower flow rates.

Hose Pumps:

Are much larger in size and can handle higher pressures which can typically operate against up to 16 bar in continuous service, use shoes and have casings filled with lubricant to prevent abrasion of the exterior of the pump hose and aids in dissipation of heat. This class of pump is often called a "hose pump".

Tube pumps:

Are designed for lower flow and lower pressure applications typically have dry casings and use rollers along with non-reinforced, tubing. This class of pump is referred to as a "tube pump" or "tubing pump".

Peristaltic Pump Advantages:

  • The only point of contact the pump has with the fluid or chemical is the interior of the tube.
  • No valves or major seals to replace on a tube pump making them low maintenance.
  • They are able to handle slurries, viscous chemicals, shear sensitive polymers and other abrasive fluids.

Peristaltic Pump Disadvantages:

  • The flexible hose or tube will tend to degrade with time and require periodic replacement.
  • Replacing the hose can get expensive and timely do to the lubricant inside the casing (tube pumps are require less maintenance).
  • With a hose pump at low flows the flow is pulsed. A hose pump is less suitable where a smooth consistent flow is required. An alternative type of positive displacement pump should be considered such as a Progressive Cavity Pump.

Typical applications for peristaltic pumps include medicine, agriculture, food processing, chemical handling, pulp and paper plants, water and wastewater treatment plants and more.