A peristaltic pump works through the alternating compression and relaxation of a hose or tube. A rotating shoe or roller passes along the length of the hose, compressing it to create a tight seal. As the roller rotates, the pinched seal advances to create a vacuum behind it that pulls in a fluid. A trailing roller reseals the hose behind the fluid to force it out through the discharge end of the pump while creating a vacuum behind the roller to repeat the process.
Because the fluid never leaves the hose while flowing through the pump, the peristaltic pump avoids contamination of the fluid or causing a reaction in the rollers or other pump parts. Peristaltic pumps are used to pump clean or sterile liquids, aggressive chemicals, high solids slurries and other material required to be isolated from the surrounding environment to prevent cross contamination.