As the composition of wastewater moves towards higher and higher levels of solids, water utilities are experiencing increasing numbers of clogging episodes and difficulty handling wastewater.
After two and a half years on the market, the Open S-tube impeller from Grundfos has proven to be a remarkable solution to that challenge. The impeller is the standard impeller in the SE/SL Range 56.
The Open S-tube from Grundfos was launched in 2021 in pumps under 30 kW, and most recently it was launched in pumps up to 63 kW when Grundfos extended the SE/SL pumps family with the Range 56 in early 2023.
“Without a single reported clogging incident to date, the Open S-tube pump ranges are as close to truly non-clogging as we can possibly get” explains Leo Andersen, Lead Product Manager, Grundfos.
“Essentially, what we offer water utilities with Open S-tube pumps in general and the new SE/SL Range 56 specifically is the confidence that the wastewater pumps they install today are prepared to handle the evolving challenges of the future.”
According to Andersen, the SE/SL range’s ability to adapt to future challenges hinges on three key factors:
- Non-clogging abilities thanks to the self-cleaning impeller design
- High efficiency across a wide range of operating conditions, which allows the pump to perform efficiently at various duty points
- Unique design that makes it the ideal replacement for virtually any wastewater pump
Self-cleaning impeller eliminates clogging episodes
Over the past 10-15 years, the composition of wastewater has changed dramatically due to increased use of wet wipes as well as separation of rain/surface water and wastewater. As a result, clogging and sedimentation has increased requiring pumps to be lifted and cleaned more often.
The Open S-tube impeller from Grundfos is engineered to combat this trend. With a semi-open design, the impeller blades work towards the adjustable suction cover that is equipped with a spin-out groove that ensures that all fibres are transported away with the sewage water.
“The hydraulic design has been adjusted to perfection through meticulous computer simulations where we ensured that all solids are constantly moved towards the pump discharge and that it is done as energy efficiently as possible,” Andersen explains and continues:
“Following the computer simulations, we carried out a series of laboratory tests using stroboscopic high-speed cameras through installed ‘windows’ in the pump housing. But we didn’t stop there. After making some hydraulic adjustments to the impellers in this new range, we initiated six field tests across Europe to make sure the impellers live up to our expectations. And we are proud to say that in the two and a half years this impeller has been on the market, not a single clogging incident has been reported.”
Impressive hydraulic and energy efficiencies can ensure significant savings
To accommodate the need to operate at changing duty points due to varying water levels in the pit, the SE/SL pumps are engineered to be able to operate efficiently across the entire curve.
“The hydraulic efficiency reaches as high as 87% which is almost unheard of for single-stage wastewater pumps,” Andersen explains.
The impeller can be trimmed to a specific duty point to ensure the pump meets the duty requirements in the installation if the pump is not operated with variable frequency drive. This ensures minimal energy consumption.
In addition to the high hydraulic efficiency, the SE/SL pumps are fitted with motors made from IE4 super efficiency components. IE4 is the highest achievable energy efficiency class for asynchronous motors according to the IEC/EN 60034-30-1:2014 standard.
The impressive hydraulic and energy efficiencies ensure a combined system efficiency of up to 80% which can help utilities achieve significant energy savings.
Seamless replacement of virtually any submersible pump on the market
The Grundfos SE/SL Range 56 pumps are carefully designed to have the most compact design with the smallest dimensions on the market. This allows for seamless integration into virtually any pump installation.
With an extensive selection of adaptors, conversion flanges, and adaptable sensor configurations, an appropriate model can typically be found to align with existing setups. Moreover, the high efficiency and lower energy consumption will often make it possible to use the existing pumping station controller and protection unit.
With sizes ranging from 25-63 kW, the range can accommodate a wide range of installations.
Duncan Leathley Area Sales Director Water Utility Grundfos UK&I says:
“Major pumping challenges Water Companies face is ensuring their assets have the highest percentage of up time when they are needed the most, the asset has solid resilient performance in challenging sewage environments, and they deliver all of this with the lowest power demand addressing net zero goals.
The Grundfos SE/SL Frame 56 Wastewater pump has been designed to achieve all of this. We are confident Frame 56 will become our customers go to pump for their most challenging pump solution demands”.
