Lobe pumps belong to the positive displacement pump category, using lobes to move fluid. An expanding volume at the inlet side of the pump is created as the lobes come out of mesh. The fluid then flows into the cavity at the inlet and is trapped by the lobes as they rotate. Next, fluid travels around the interior of the casing in the pockets between the lobes and the casing. Finally, the meshing of the lobes forces liquid through the outlet port under pressure.
Lobe pumps are frequently used in food applications because they handle solids without damaging the product. Particle size pumped can be much larger in lobe pumps than in other PD types.