Lobe Pumps
What is a lobe pump?
A type of positive displacement pump that moves liquid by passing it across two rotors containing lobes. Each rotor is located on its own shaft, with the lobes meshing as they rotate inside the pump casing. The pump very gently moves liquids containing fragile solids, and is available in sanitary (hygienic) designs, so this pump type is particularly popular in the food, beverage, and biotech industries.
How do they work?
As the two rotors, each of which has two or three lobes, turn in the casing, a vacuum is created at the inlet, which draws the liquid into the pump. As the rotors turn, the liquid is carried between the spaces created between the lobes and the casing.
A lobe pump is similar in concept to an external gear pump. However, unlike the gears used in a gear pump, the lobes in a lobe pump do not come in contact with each other as they rotate. That is, one lobe cannot drive the other one. Instead, external timing gears that are outside of the pump casing and in an oil bath, but mounted on the same two shafts, assure that the lobes keep a very precise and close clearance as they rotate, without ever making contact.
The main advantage is that the rounded edges of the lobes and the large spaces between the lobes and the casing means that fluid containing fragile solids can be pumped gently, with minimal damage to any solids that are in the fluid.
Where are they used?
Because lobe pumps are very gentle and are available in sanitary (hygienic) designs, they're commonly used for moving and processing food-based liquids, especially those that have some solid content. For example, they are used to pump soups and ice cream containing nuts or fruit. They’re also used to handle fermentation products in bio-processing, and in industrial applications for the processing of materials such as polymers, soaps, paints, and adhesives. Non-sanitary versions are used to handle wastewater sludge.
Other related pump types include: rotary pump, chemical pump, industrial pump, reciprocating pumps, process pump.
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