High-performance coating prolongs pumps’ service life
The NoriResist high-performance coating by the KSB Group is a world novelty in carbon-based surface technology for pumps and valves.
It markedly increases the durability and efficiency as well as the sustainability of modern pump systems. Close cooperation between research, application technology and industry partners formed the basis of this development. The new coating primarily aims at applications in waste water and process engineering.
NoriResist is a diamond-like carbon coating applied to hydraulic components, such as impellers, wear plates, discharge covers, casing wear rings and impeller wear rings. It can also be used for coating the casings of close-coupled pumps. Suitable base materials are grey cast iron, nodular cast iron and steel materials. The coating can also be applied to other parts – even to selected plastic components.
With a hardness of 4000 to 8000 HV (40–80 GPa) NoriResist is highly resistant to abrasive wear, especially from fluids containing sand. With layers in the micrometre range, the component weight, dimensional accuracy and hydraulic contours remain practically unchanged. This means the impellers do not need to be re-balanced after they have been coated. The low coating temperature prevents any warping of components or microstructural changes.
In numerous field tests with severely contaminated waste water applications the newly developed coating proved to be as high-performing as expected. While conventional coatings showed clear signs of wear and efficiency reduction after a short operating time, the surface quality of components with the new coating remained almost unchanged also after thousands of operating hours. The pumps’ hydraulic efficiency remained constant over a long period of time.
A decisive advantage is that coated components remain true to their original contour. The sharpness of the vane edges is also maintained for longer, which clearly helps reduce flow separation losses and efficiency losses. In practice, the service life can be up to three times as long as that of uncoated or conventionally coated components.
The coated surface is further characterised by a very low friction coefficient and can reduce adhesion and deposits. This enhances the operating reliability, especially in applications where abrasive and/or corrosive fluids are handled. The chemically inert coating is also resistant to a large number of aggressive substances contained in the fluid and thermally stable up to about 500 °C.
The carbon-based coating is environmentally sustainable and recyclable. Apart from the technical benefits, this also results in a measurable contribution to environmental protection. Unlike with conventional coating solutions, no plastic and heavy metal particles are released. Prolonged maintenance intervals and a reduced spare parts demand also lower the resource consumption and life cycle costs of the pumps.