Hospitals typically use them for pumping IV fluids and in heart and lung machines during bypass surgery. We’re talking about the parametric pump, which are used to move sterile or clean fluids without becoming cross contaminated. They work by squeezing a length of tube fitted inside a circular casing, which compresses the tube using rollers thereby pushing the fluid inside.

As you could imagine, these types of pumps are on the expensive side (a few hundred bucks at the very least), however they can be 3D printed on the cheap, which was detailed in a blog from by [Tim] on his website (http://tim.cexx.org). He based his parametric peristaltic pump on emmett’s planetary gear bearing design that uses gears to move fluid rather than rollers or shoes. He designed his pump using the versatile OpenSCAD 3D CAD modeler and printed it out using a Lulzbot 3D printer. What makes it interesting is that the pump is printed already assembled in one piece, only add tubing when done!