KSB develops new wastewater impeller

The KSB Group has developed a new radial multi-vane impeller in open design that is suitable for handling untreated wastewater.

The new D-max impeller from the KSB Group
The new D-max impeller from the KSB Group - Image © KSB SE & Co KGaA.

The D-max impeller can handle fluids containing solid substances and long fibres, coarse solids as well as entrapped gas or air. It is suitable for untreated wastewater, combined sewage, recirculated and heating sludge as well as activated, raw and digested sludge with a solids content of up to 8%. The impeller is also suitable for transporting fluids with a high viscosity.

At approximately 84%, the new impeller's best efficiency can be compared with the performance of closed multi-channel impellers. The free passage is at least 76 mm.

KSB's hydraulic experts employed computational fluid dynamics (CFD) to obtain detailed knowledge about the complex flow processes inside the pumps via computer-aided simulations. In addition to the computer-aided development of impellers, KSB also conducted wastewater tests in the laboratory as well as intensive field tests around the world. The results of these tests were then incorporated into the development work.

Each customer receives an impeller trimmed to match the specified operating point. This is also common practice for multi-channel impellers.

The D-max impellers are used in KSB’s Sewatec and Amarex KRT pump type series. They are suitable for both 50 Hz and 60 Hz electric motors. The maximum head is approximately 90 metres and the maximum flow rate is approximately 2,800 cubic metres per hour. Depending on the composition of the wastewater, an operator can choose between the materials EN-GJS-400-15 and 1.4517 as well as EN-GJN-HB555.