Typically used for wastewater, N-pumps create big savings for a dewatering project in southern Germany.
FOR GERMAN CONSTRUCTION company Wayss & Freytag, choosing the right pump meant big savings. “The customer needed only half the number of pumps, half the amount of electricity, half the amount of pipe, and half the number of switchboards,” says Jens Hallmann, Business Unit Manager Dewatering at Xylem’s Langenhagen office.
After 80 years, part of the Isar Canal north of Munich needed repairs to shore up its concrete and prevent future cracks. Before work could begin, however, the canal had to be “dewatered” and its water levels lowered or even, in certain places, completely drained.
Initially, Wayss & Freytag planned to use 36 drainage pumps. Xylem in Langenhagen, Germany, suggested that the work could be done using only 18 Flygt N-pumps, models that are normally used for wastewater.
THE CONSTRUCTION company approached the end user, E.ON. A major energy provider in Germany, E.ON owns the hydroelectric plants that use the canal section, located between Finsing and Pfrombach, which needed repair. E.ON was pleased with Xylem ’s solution, which saved money on both materials and electricity.
During the project’s short timeframe – from May to November 2009 – the pumps removed more than 15 million cubic meters of water. The 18 Flygt N-pumps (NS 3301) were more energy-efficient than standard drainage pumps, mostly because their sixpole motors turned more slowly, and for the same amount of electricity – 55 kilowatts – they could pump twice the volume of a standard draining pump.
Twelve of the 18 Flygt pumps ran 24 hours a day. The remaining pumps got switched on by demand. All pumps were covered with fine steel mesh to protect the canal’s fish.
Once the job was done, Xylem bought back the pumps, which are now being used in the company’s rental program Once the job was done, Xylem bought back the pumps, which are now being used in the company’s rental program.