Case
New Open S-tube® hydraulics resolve ongoing clogging issues at a wastewater pumping station in Budapest, Hungary
When the representatives of Budapest Sewage Works asked Grundfos to resolve ongoing clogging issues at a combined wastewater and stormwater pumping station in Budapest, Hungary, Grundfos supplied an Open S-tube® impeller. The installation has now run for two years without any clogging incidents.
Since the installation of the three mid-sized wastewater pumps, the water utility has experienced constant clogging issues. Following lifting and cleaning, the pump has on occasion only operated for 10 minutes before clogging again. This pattern of clogging issues after a short period of operation has been reported with all three pumps, due to the extreme level of contamination with huge amount of fibrous material. The requirement was to ensure a non-clogging solution for the three mid-sized pumps. This would avoid the three large and oversized pumps cutting in when not otherwise required.
Open S-tube® semi-open impellers with two or more channels provide high efficiency and are ideal for frequency drive operation and a wide operating area. They are available on Grundfos SE/SL pumps, together with a range of hydraulic designs, including Closed S-tube® impellers and SuperVortex free-flow impellers, for reliable and efficient operation with the highest level of performance in all wastewater applications.
The solution
There have been many failed attempts to resolve these issues over the years, including changing the pump impeller from 2-channel to 1-channel type, replacing the suction elbow, setting up the controller logic to decrease the possibility of clogging, and building in a special flow deflector device, called a shark fin, to change the turbulence in the suction pipe. Finally, an Open S-tube® impeller was installed in one of the three mid-sized pumps, and the remaining pump 22kW has been replaced entirely which is also equipped with an Open S-tube® impeller.