German pump manufacturer KSB has developed a new free-flow impeller for wastewater pumps, capable of delivering high efficiencies and reliable service.
The F-max impeller now incorporates different distances between its blades, which are arranged in groups with two small and two large distances.
The asymmetrical blade arrangement offers wide free passages, ensuring that even larger rigid solids pass easily and are reliably handled by the pump.
The blades are also able to create a swirling effect in the hub area, which shifts fibres away from the impeller hub and transports them to the outside.
Subsequent balancing is no longer required with the new impeller type as the radial forces and vibrations created are usually lower than those of single-channel impellers, which increases the service life of shaft seals and rolling element bearings.
Pumps with F-max impellers thus require only minimal maintenance, and replacing the impeller itself is straightforward.
When they rotate, free-flow impellers develop a strong swirl, which keeps the solids in the pump casing suspended and – in combination with the inclined suction area – generates an additional flushing action.
This operation reduces the risk of clogging in the impeller's centre caused by long fibres, in particular by wet wipes, which have become a major problem in waste water transport as their use has markedly increased in the last few years.
As a result of the trend towards conserving drinking water and separating stormwater and wastewater, the wastewater to be handled has become thicker.
This is why operators now demand non-clogging impellers which offer reliable operation without sacrificing high efficiencies, even for small waste water pumps.
KSB will exhibit the F-max impellers at this year's IFAT trade show in Munich.