Grundfos’s S-tube impeller is a tube-shaped impeller with a simplistic design. The smooth impeller is free of any obstructions as there are no cutting or moving functions that would increase its susceptibility to wear. This allows for uncompromised free passage of effluents and suspended solids with a spherical free passage of up to 160 mm.

The S-tube impeller complements Grundfos’s SE and SL range of submersible wastewater pumps. The improved impeller design effectively boosts hydraulic efficiency. Semi-open impeller designs matched to an SE or SL pump experience limited range with only 22% of the flow curve exceeding a hydraulic efficiency of 75% and free passage of only 55 mm. With the S-tube 55% of the flow curve is above the same threshold and free passage is more than doubled.

The S-tube impeller boasts a hydraulic efficiency of up to 84%. It provides for increased reliability, and test results report lower noise, less vibration, reduced maintenance and improved non-clogging capabilities over existing designs.