Progressive Cavity Pumps

Stator elastomer must be chemically compatible with the pumped fluid — NBR (nitrile) is the general-purpose choice for oils and water-based fluids, EPDM works well with many alkaline and chemical fluids but degrades rapidly in contact with petroleum products, and fluoroelastomer (Viton) handles a wider range of aggressive chemicals at a higher cost. Using an elastomer incompatible with the fluid causes swelling, softening or premature stator failure regardless of how well the pump is otherwise sized.

The rotor's eccentric motion forms a fixed number of sealed cavities per revolution that move a consistent volume of fluid from suction to discharge, so total flow scales directly and nearly linearly with rotor RPM, largely independent of discharge pressure within the pump's rated range. This predictable relationship is why PC pumps are widely used for metering and dosing duty.

Abrasive and high-solids fluids accelerate stator wear at the rotor-stator interface, so pumps for these services typically use a harder stator compound and increased rotor/stator clearance to reduce direct wear contact, at some cost to volumetric efficiency. Matching stator hardness and clearance to actual solids content and particle size is key to acceptable wear life.

Maximum differential pressure is a function of the number of pumping stages — each rotor/stator lobe pair contributes a fixed pressure increment — so a multi-stage pump can be specified for higher discharge pressure applications by adding stages, rather than needing a fundamentally different pump technology.

Yes, when built with sanitary-polished stainless steel wetted parts, crevice-free design and FDA-compliant elastomers meeting 3-A or EHEDG standards. These sanitary PC pumps are specifically valued in food processing for their low-shear handling of viscous, particulate-containing products like sauces and purees that would be damaged by higher-shear pump types.