Non-contacting Rotary Lobes
Rotary lobe pumps are positive-displacement type pumps that use two or more lobes rotating around parallel shafts in the pump’s body to move liquids. They are widely used in the hygienic processing industries, including food & beverage processing and biopharmaceutical manufacturing.
Unlike gear pumps, the lobes used in these pumps do not make physical contact with each other, a feature that provides some distinct advantages in pumping certain types of materials. The shafts to which the lobes are attached rotate in opposite directions when in operation. This process repeatedly creates collapsing cavities inside the pump, and moves out products through the discharge.
Positive Displacement Pump
Inside a lobe pump, fluid flows around the interior of the casing. Unlike external gear pumps, however, the lobes do not make contact. Lobe contact is prevented by external timing gears located in the gearbox. Pump shaft support bearings are located in the gearbox, and since the bearings are out of the pumped liquid, pressure is limited by bearing location and shaft deflection.
As the lobes come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the lobes as they rotate. Liquid then travels around the interior of the casing in the pockets between the lobes and the casing. Basically, fluid does not pass between the lobes. Finally, the meshing of the lobes is what forces the liquid through the outlet port under pressure.
