SonFlow / DanPumps S-WN Wastewater Pumps
The S-WN series comprises dry-installed centrifugal wastewater pumps, suitable for horizontal or vertical mounting in pumping stations, industrial effluent networks, and wastewater treatment facilities. Both suction and discharge connections are flanged. Drive is provided by an air-cooled IEC electric motor.
Operating Range
Flow rates from 68 to 4000 m³/h are covered, with connection diameters from DN80 to DN600. Models S-WN1 to S-WN5 address different duty points. Maximum ambient and liquid temperature is 75 °C.
Compatible media include:
- municipal sewage and untreated wastewater
- industrial effluents
- contaminated water with suspended solids
- sludge, septic waste, and fibrous media
- stormwater and drainage water
Impeller Selection
Impeller type is selected based on solids content, clogging risk, and required hydraulic efficiency.
- Single- or double-channel impeller: higher efficiency, moderate clogging risk
- B-tween impeller: intermediate solution for wastewater with elevated solids or fibers
- Vortex impeller: increased free passage, reduced clogging probability
- Cutter impeller: for shredding solids such as rags, plastics, sanitary waste, and organic debris
Materials and Sealing
Pump casing: GJL-250; impeller: GJS-400-15 (optional AISI 316); shaft: AISI 431; O-rings: NBR. Shaft sealing is via double mechanical cartridge seal: SIC/SIC on the media side, SIC/Carbon on the cooling side. Cartridge design reduces seal replacement time and assembly errors during maintenance.
Motors and Control
Supplied with IP55, IE3 motors, 2/4/6 poles, insulation class F (optional H). Inverter operation supported. ATEX versions available for hazardous areas.
Installation
Horizontal version is base-mounted for easier access to hydraulic components. Vertical version has a smaller footprint, adjustable feet, and top pull-out design.
FAQ
When is a vortex impeller selected?
When priority is free solids passage rather than maximum hydraulic efficiency.
Can the pump be serviced without disconnecting pipework?
Yes, the pull-out design allows motor and hydraulic section removal without detaching the pump from the network.


















