What principle does a roller pump operate on?

A roller pump operates on the principle of positive displacement. This means that the pump moves a fixed volume of fluid with each cycle of its mechanism, regardless of the resistance in the system downstream. The design of the roller pump facilitates this through rollers that compress a flexible tube containing the blood or fluid being pumped. As the rollers move, they create a vacuum that pulls fluid into the tube, and then the compression of the tube pushes the fluid forward.

Positive displacement is key in ensuring a consistent flow rate, which is crucial in perfusion applications where maintaining blood flow and pressure during procedures like open-heart surgery is necessary. The ability to provide a predictable and controllable flow is one of the primary reasons roller pumps are favored in cardiovascular perfusion settings.