Lobe pump

A lobe pump is a type of rotary positive displacement pump. It utilizes two or more rotors, called lobes, which rotate within a casing to create a vacuum at the inlet and force fluid out of the outlet. Unlike gear pumps, the lobes do not make contact. Instead, timing gears positioned external to the pump chamber ensure that the lobes rotate without touching. This design allows lobe pumps to handle solids without damage.

Principle of Operation

As the lobes rotate, they create expanding volume on the inlet side of the pump. This expanding volume draws fluid into the pump. The fluid is then trapped between the lobes and the pump casing. As the lobes continue to rotate, they force the trapped fluid around the casing and out through the discharge port. The close tolerances between the lobes and the casing, though without actual contact, minimize backflow, thus maintaining consistent flow rates.

Applications

Lobe pumps are commonly used for a wide range of applications due to their ability to handle a variety of fluids, including viscous liquids, shear-sensitive fluids, and fluids containing solids. Some common applications include:

• Food processing (e.g., pumping sauces, pastes, and whole fruits)
• Chemical processing (e.g., pumping polymers, resins, and acids)
• Pharmaceuticals (e.g., pumping creams, lotions, and suspensions)
• Wastewater treatment (e.g., pumping sludge and slurries)
• Pulp and paper industry (e.g., pumping coatings and adhesives)

Advantages

• Handles solids and slurries without damage
• Self-priming capabilities
• Reversible flow
• Gentle pumping action, suitable for shear-sensitive fluids
• Good for high-viscosity fluids
• Relatively easy to clean and maintain

Disadvantages

• Generally more expensive than some other pump types
• Requires external timing gears
• Can be noisy in operation, especially at high speeds
• Pulsation can be present, requiring pulsation dampeners in some applications