Gear and Lobe Pumps

The efficiency of a centrifugal pump falls sharply as viscosity rises; in gear and lobe pumps the fluid is trapped in the cavities between teeth or lobes and carried to the discharge side. This is why they are chosen for oils, resins, molasses, adhesives, paints and polymers. Flow is proportional to speed, so precise adjustment is possible through speed control.

Models in our catalog offer connections from ½" to 6", maximum flow from 0.54 m³/h to 20 m³/h and a pressure range of 1–14 bar. The temperature range is 20–200 °C and viscosity capacity is 100–25,000 cP; displacement per revolution varies between 0.006 L/rev and 0.667 L/rev.

Casing and gear materials are available in GG25 cast iron, AISI 316 stainless steel and bronze. Bearings are bronze, carbon-filled PTFE or rolling element; sealing is configured as soft packing, mechanical seal or lip seal. A heating jacket can be added for hot or freeze-prone fluids, and a strainer and by-pass for line protection.

The lobe design suits products carrying solid particles and sensitive to shear (food, cosmetics); the internal gear design runs quietly and without vibration at high viscosity. For why the three constructions diverge with different fluids see our viscous fluid transfer guide, and for material compatibility our chemical compatibility chart.