What is a peristaltic pump?

A peristaltic pump is a type of positive displacement pump used for pumping a variety of fluids. It is also commonly known as a roller pump.

• Working Principle: The pump works by compressing a flexible tube or hose containing the fluid. A rotor with a number of "rollers," "shoes," or "wipers" attached to it compresses the tube, creating a seal and forcing the fluid through the tube. As the rotor turns, the compression moves along the tube, continuously pushing the fluid forward. After the roller passes, the tube recovers its shape, drawing more fluid into the pump. This process is known as peristalsis, the same mechanism used by the digestive system to move food.

• Key Components:

  • Tube/Hose: Made of flexible material compatible with the fluid being pumped. Common materials include silicone, elastomers, and PTFE.
  • Rotor: Holds the rollers/shoes/wipers.
  • Rollers/Shoes/Wipers: Compress the tube.
  • Housing: Encloses the mechanism.

• Advantages:

  • Self-priming: Can draw fluid from a source without needing to be pre-filled.
  • Dry-running capability: Can operate without fluid without damage for short periods.
  • Low shear: Gentle pumping action, minimizing damage to shear-sensitive fluids (e.g., cell cultures, polymers).
  • Sterile Fluid Transfer: The fluid only contacts the inside of the tube, making it ideal for applications requiring high purity or sterility.
  • Reversible: Flow direction can be easily reversed.

• Disadvantages:

  • Pulsating flow: Flow is not continuous but rather consists of pulses, although multi-roller designs minimize this.
  • Tube wear: The tube is subject to wear and tear due to repeated compression and needs periodic replacement.
  • Limited pressure capability: Generally not suitable for high-pressure applications.
  • Efficiency: Lower efficiency compared to some other pump types.

• Applications:

  • Medical: Dialysis machines, blood pumps, drug delivery systems.
  • Pharmaceutical: Dispensing, filling, and transferring sterile fluids.
  • Chemical Processing: Metering and dispensing chemicals.
  • Food and Beverage: Dispensing sauces, fillings, and other fluids.
  • Wastewater Treatment: Dosing chemicals, sludge transfer.
  • Laboratory: Handling corrosive or sensitive fluids.

• Types:

  • Hose Pumps: Use larger diameter, reinforced hoses.
  • Tube Pumps: Use smaller diameter tubing.

• Selection Criteria: Considerations for selecting a peristaltic pump include flow rate, pressure requirements, fluid compatibility with the tube material, viscosity of the fluid, and the required level of accuracy.