Features
In applications demanding extreme corrosion resistance or sanitary purity, medium-opening pumps are manufactured with specialized features. The axially split casing allows complete access to all wetted surfaces, essential for thorough cleaning in food or pharmaceutical settings. The double-suction design inherently provides low fluid velocity and gentle handling, making it ideal for shear-sensitive products. Modern designs feature back pull-out capability combined with split casing, reducing downtime. Other features include flush-mounted connections to eliminate crevices where bacteria could grow, polished surface finishes (Ra < 0.8 μm), and oversized seal chambers to accommodate high-performance mechanical seals. These pumps also excel at handling fluids containing soft solids or crystals because the open passages of the double-suction impeller reduce clogging risk.
Material Selection
Sanitary and corrosive duties require high-grade alloys and non-metallic coatings. The most common material is 316L stainless steel (low carbon for weldability and corrosion resistance), often with electropolished surfaces. For severe corrosive media like concentrated acids or chlorides, Hastelloy C-276 or Titanium Grade 2 is specified. In desalination plants, Super Duplex (UNS S32750) provides outstanding resistance to chloride stress corrosion cracking. Non-metallic options include polypropylene or PVDF casings for low-pressure acid handling. Elastomers must be FDA-compliant, using FKM (Viton) or EPDM, while silicone or PTFE is used for high-purity water.
Applicable Industries
The pharmaceutical industry uses these pumps for WFI (Water for Injection) circulation and buffer solution transfer. Food and beverage applications include syrup, juice, and dairy product pumping where clean-in-place (CIP) is routine. Desalination plants rely on corrosion-resistant medium-opening pumps for reverse osmosis feed and brine transfer. The chemical processing industry uses them for handling aggressive acids, bases, and solvents. Microelectronics manufacturing also depends on them for ultrapure water systems. Wherever product purity, corrosion resistance, and easy inspection are mandatory, this pump type is preferred.
