New Grundfos impeller design delivers reliable pumps in high solids applications

15th October 2021

New Grundfos impeller design delivers reliable pumps in high solids applications

Increased levels of rags and fibrous solids in South Africa’s wastewater systems call for the innovative design and reliability of the new Grundfos SE/SL wastewater pumps.

With their semi-open hydraulic design, these Grundfos submersible pumps can deal with today’s demands – even rags and organic solid objects – without blocking up and causing pump stoppages. Any blockages at wastewater pump stations and treatment plants can cause tanks to overflow, causing environmental damage by discharging into river systems, wetlands and even groundwater aquifers.

The specially designed Open S-tube® impeller optimises durability by allowing solid objects to quickly pass through the pump without affecting performance, ensuring high wire-to-water efficiency. 

In addition to using virtual simulation tools in designing this solution, Grundfos conducted extensive field testing on these pumps for the past two years. Hydraulic performance tests follow the ISO 9906 standards, while clogging tests are conducted according to the well-regarded methodology of the Technische Universität Berlin.

This reliable product can be combined with a Grundfos monitoring and control system, which allows the system to be monitored for unforeseen events and minimalize risks. An early warning signal can be generated if there is a need for an operator to mobilise a maintenance team to action. Prompt attention can then prevent any serious impact on operations or the local environment. 

The southern African market is already familiar with the quality of the first-generation Grundfos SE/SL pumps, which have established a strong installed base over the past two decades. Building on the proven design with original cast iron volutes and stainless steel housing, the new impeller design also offers energy savings. A guide vane option to 
the design improves performance for conditions of particularly high solids; this option guides material into the leading edge of the impeller, for quick expulsion from the pump. 

This is an important feature of the new generation of Grundfos SE/SL pumps, as it avoids high torque demand caused when water and rags are prevented from moving freely through the pump. These conditions can trip the motor as a safety measure and stop the pump, leading to wastewater build-up and inevitably a sewage spill into the environment.