Peristaltic Pumps : How do they work?

 

 

Peristaltic pump in motion

 

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 fitted inside a circular pump casing (though linear peristaltic pumps have been made). 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 part of the tube under compression is pinched closed (or "occludes") thus forcing the fluid to be pumped to move through the tube. Additionally, as the tube opens to its natural state after the passing of the cam ("restitution" or "resilience") 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.

Applications

Peristaltic pumps are typically used to pump clean/sterile or aggressive fluids because cross contamination with exposed pump components cannot occur. Some common applications include pumping IV fluids through an infusion device, aggressive chemicals, high solids slurries and other materials where isolation of the product from the environment, and the environment from the product, are critical. It is also used in heart-lung machines to circulate blood during a bypass surgery as the pump does not cause significant hemolysis.

Peristaltic pumps are also used in a wide variety of industrial applications. Their unique design makes them especially suited to pumping abrasives and viscous fluids.

source  : Wikipedia