QBY Diaphragm Pump Material Selection – PP, Aluminum, Cast Iron & Stainless Steel Options

The QBY series air-operated diaphragm pump is available in four primary body materials to suit different chemical environments. Engineering plastic (PP) is lightweight, cost-effective, and offers excellent resistance to many acids, alkalis, and solvents. Aluminum alloy provides a good balance of strength and weight reduction, making it suitable for general industrial applications. Cast iron offers durability and wear resistance for abrasive slurries and heavy-duty use. Stainless steel (typically 304 or 316) provides superior corrosion resistance for aggressive chemicals, food processing, and pharmaceutical applications.
Diaphragm material selection is equally critical for pump performance and longevity. Standard options include nitrile rubber (NBR) for oils and fuels, neoprene (CR) for general purpose use, fluororubber (FKM/Viton) for strong acids and high-temperature fluids, and polytetrafluoroethylene (PTFE) for maximum chemical resistance and high purity applications. The correct combination of body and diaphragm material ensures long service life and reliable operation under demanding conditions.
The pump’s wetted parts are designed to minimize chemical attack and mechanical wear. The ball valves and seats are available in matching materials to maintain sealing integrity. The pump can handle temperatures ranging from -15°C to +150°C depending on the material selection. For extreme environments, such as concentrated acids or high-temperature solvents, PTFE diaphragms combined with stainless steel bodies provide the highest level of protection against corrosion and degradation.