How to Adjust the Occlusion of a Peristaltic Pump

Designed for the pumping of fluids, the peristaltic pump utilizes positive displacement to move liquids through narrow tubing. There are several features of a peristaltic pump critical to its function. First, fluid is moved through a flexible tube that has been placed inside a circular frame. A rotor with several attached rollers is located in the center of the structure; when this device rotates, the rollers compress the flexible tubing against the circular frame. Any fluid contained within the tubing is consequently driven in the direction of the spinning rotor, thus generating the pumping force required to move the fluid. The amount of pressure applied to the tubing determines the "occlusion," or the squeeze placed on the fluid. The higher the occlusion, the more efficiently the pump moves fluid. The occlusion can be adjusted by changing one of two values: the thickness of the tubing wall or the gap between the roller and the circular frame.

Instructions

• 1

  Adjust the gap between the roller and the circular frame. The smaller the gap, the more squeezing pressure that will be applied to the fluid within the tubing as the roller rotates inside the pump. This can be accomplished by manually shifting the rollers farther away from the axis of the rotor, thus decreasing their distance from the circular housing frame.

• 2

  Use tubing with different wall thickness. The thicker the wall of your tube, the more occluded the fluid will become as the roller rotates. Tubing with a thin wall will apply less squeezing pressure on the fluid, thus decreasing the occlusion of the pump. Changing tube thickness has a greater impact on occlusion than adjusting the gap. This is because occlusion is proportional to two times the wall thickness multiplied by the gap.

• 3

  Prepare replacement tubing as needed. Adjusting the occlusion not only alters the efficiency of the pump but also the lifespan of the tubing. By increasing the occlusion, you are squeezing the tubing with greater force, which will wear out the tubing material faster.