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" or "wipers" attached to the external circumference compresses the flexible tube. As the rotor turns, the part of tube under compression closes (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") fluid flow is induced to the pump. This process is called peristalsis and used in many biological systems such as the gastrointestinal tract.
Many older hose pumps use shoes to compress the hose. When the shoe slides over the outside of the hose, it creates friction and heat, and heat is an enemy of long hose life. A single roller pump uses a large diameter lubricated roller on an eccentric shaft that rolls over the hose. This means that it produces less friction, and therefore less heat, than a pump with shoes.
In addition to less heat, an eccentric shaft hose pump functions with only a single compression of the hose per revolution. For every one rotation, the pump has one compression of the hose, while pumps with multiple shoes or rollers have at least two compressions per revolution, and in some cases three or four. Since the hose is the heart of a peristaltic hose pump, and hose life is inversely proportional to the number of squeezes, this design will outperform a pump with shoes at the same speed.
The hose in this type of pump takes up the full 360 degrees of the pump housing. This is important, because at an equal size, this design will produce 55% more flow at the same speed. This means that one can get more flow at the same pump speed, or run the pump more slowly to generate the same flow.
Wipo Publishes Patent of Fresenius Vial, Sebastien Labarthe and Jean-Baptiste Berthier for "Peristaltic Pump for Pumping a Liquid and Method for Operating a Peristaltic Pump" (French Inventors)
Apr 28, 2013; GENEVA, April 28 -- Publication No. WO/2013/057109 was published on April 25.Title of the invention: "PERISTALTIC PUMP FOR...