Lobe contact is prevented by external timing gears. Pump shaft support bearings are located in the timing gear case. Since the bearings are out of the pumped liquid, pressure is limited by bearing location and shaft deflection. Use of multiple mechanical seals makes seal construction important. Lobe pumps are frequently used in food applications, because they handle solids without damaging the pump.
Particle size pumped can be much larger in lobe pumps than in other PD types.
Since the lobes do not make contact, and clearances are not as close as in other PD pumps, this design handles low viscosity liquids with diminished performance. Loading characteristics are not as good as other designs, and suction ability is low. High-viscosity liquids require considerably reduced speeds to achieve satisfactory performance. Lobe pumps are cleaned by circulating a fluid through them. Cleaning is important when the product cannot remain in the pumps for sanitary reasons or when products of different colors or properties are batched.