page_title: Peristaltic pump
section_title: Microfluidic pumps
hierarchical_section_title: Peristaltic pump / Variations / Microfluidic pumps
caption_attribution_description: English: The pumping sequence used in a pneumatically-actuated microfluidic peristaltic pump.
context_page_description: A peristaltic pump, also commonly known as a roller 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. 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 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 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.
context_section_description: In microfluidics, it is often desirable to minimize the circulating volume of fluid. Traditional pumps require a large volume of liquid external to the microfluidic circuit. This can lead to problems due to dilution of analytes and already dilute biological signalling molecules.
  For this reason, among others, it is desirable to integrate a micro-pumping structure into the microfluidic circuit. Wu et al. presented in 2008 a pneumatically actuated peristaltic micropump which eliminates the need for large external circulating fluid volumes.
caption: The pumping sequence used in a pneumatically-actuated microfluidic peristaltic pump.[11]
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