Borehole Pumps With Optimised Efficiency

They are characterised by a notably lower electricity consumption compared to the previous series and can be applied both in water supply and water drainage.

The “Wilo EMU NK 86” and “Wilo EMU NK 87” borehole pumps cover a wide range of applications, ranging from pumping potable or industrial water from wells, sumps, waters or tanks through providing process water and pumping chemically aggressive fluids in industry installations up to applications in the offshore sector.

The development of the new borehole pump generation focused on improvement of the efficiency in the maximum output area and the energy saving resulting from it. Optimised hydraulics, for example, allowed for an increase of the “Wilo EMU NK 87” pumps’ efficiency by approx. 4% to up to 80% compared to the previous models of the “Wilo EMU K 87” series.

Thanks to this improvement, life cycle costs are considerably reduced as the model calculation proves. With the same volume flow and delivery head, power consumption of the new “Wilo EMU NK 87” is reduced by 1.5 kW. For an assumed annual operating time of 7,300 hours and an electricity price of 0.15 Euros/kWh, energy costs are reduced by approx. 1,640 Euros per year. Thus replacing an old pump, which is still in working order, with a new “Wilo EMU NK 87” pump pays off within a few years already.

Efficiency can be further increased by means of the innovative “Ceram CT” coating. This is a coating with KTW approval (German water regulations advisory scheme) which was particularly designed for borehole technology. It is applied on the impeller blades and the inner contour as well as on the inside of the stage housing. The “Ceram” coating is characterised by a low surface roughness. This also contributes to an increase of the overall efficiency.

Both series comprehend different pump types with nominal motor powers of 10 to 110 kW. The motors are optionally available in rewindable version either filled at the factory or filled with potable water. Alternatively, the pumps can be equipped with all commercially available 6ʺ and 8ʺ submersible motors in accordance with the NEMA standard. The powerful models are dimensioned for a maximum volume flow of 200 m³/h or a zero delivery head of up to 320 m.

Due to different material versions the pumps can be exactly adapted to the respective field of application and the fluid to be pumped. The standard version for normal waters has a cast iron housing with a high-value two-component coating. The impeller and the shaft are manufactured in corrosion-resistant materials like bronze or top-quality stainless steels. Units are also available in zinc-free bronze for use with chemically aggressive fluids. The offshore version consists of NiAl-bronze in conjunction with top-class duplex steels. The pumps can be installed with up to six stages horizontally or with up to twelve stages vertically. In both installation positions they can be equipped with a cooling shroud.