Progressive cavity pumps are another type of positive displacement pump. They are most popular in heavy-duty industries because of their excellent handling of highly viscous fluids like grease, crude, heavy fuel, lubricating oils, and bunker fuel. In addition, this pump type comes in many models to suit different applications such as dosing, drum emptying, metering, and hygienic applications.
Progressive cavity pumps utilize the power of a rotor and stator assembly to create temporary chambers where fluid is drawn into. The rotor is a helical-shaped worm component that rotates within the stator. The stator is made from a flexible material and has one more ‘worm thread’ than the rotor. This design allows for both the rotation of the stator and the provision of a shifting space which forms the progressing cavity necessary for the fluid.
Helical Rotor and Stator Assembly
Pumping performance is achieved through positive displacement. A screw-shaped rotor is placed within a stationary stator, to form a number of cavities containing fluid. These cavities are progressed forward through the pump by the rotating action of the rotor, creating a continuous flow.
As such, the pumps are constructed from a large number of consumable parts-a rotor, a stator, a coupling, a drive shaft, a mechanical seal.
Limitations are the large footprint of the design and the significant downtime required for maintenance due to a large number of moving parts over other pump types.
