Sustainability and a second life

It is very common these days for power stations to operate vertical centrifugal pumps for transporting turbine condensate that have long exceeded their service life. EAM Natur Energie GmbH has been using such a centrifugal pump – made in 1967 – in the HKW Göttingen (combined heat and power station). Even just by looking at this pump set it was apparent that it had long exceeded its useful life when it finally stopped working. After more than 50 years, it was hardly surprising that procuring spare parts was unsuccessful. The reliable service partner KSB SupremeServ took on the task of repairing this third-party product.

Close-by, natural, sustainable: EAM is the regional energy partner for about 1.4 million people in a region spanning large parts of Hessen, southern Lower Saxony and parts of North-Rhine Westphalia, Thuringia and Rhineland Palatinate. 100 percent a municipal company, EAM ensures reliable energy supply, develops future solutions for its customers and is one of the partners contributing to the region's energy transition. Its subsidiary EAM Natur Energie offers solutions for wind power, PV, electro mobility and CO₂-free heat, for example. As a generating expert EAM Natur Energie also operates the combined heat and power station in Göttingen. 

Oxidised iron had been depositing on the pump for decades. This resulted in magnetite swelling up the surface of the entire pump to such an extent that efficient operation was no longer possible.

The original manufacturer Halberg no longer had any spare parts for this pump in its programme; reproducing the impeller the classic way would have costed nearly as much as buying a new pump.

If the pump had to be replaced by a new model, costly changes to the entire system, such as piping, valves and condensate tanks would have been unavoidable.

In conformity with DIN ISO 9001 KSB SupremeServ created a detailed damage report and developed an action plan for an economically viable pump repair. Apart from freeing the casing from magnetite using a special mechanical procedure, repairing the centrifugal pump mainly meant replacing its highly complex impellers.

For more than 10 years, KSB has been consistently involved in the field of additive manufacturing, also commonly known as 3D printing. The largest benefits of additive manufacturing are the high speed in which components can be manufactured, and its cost efficiency. Another advantage is the ability to process an immense diversity of materials and shapes, including complex components. Without wanting to outcompete series production by casting, 3D printing is especially suitable for producing single individual components, such as spare parts. It was therefore an ideal option for reproducing the two impellers that were no longer available.

At the Pegnitz site, KSB has installed the largest 3D printer worldwide for creating workpieces from metal powder using a laser beam. KSB was the first ever manufacturer to receive a TÜV certification for using this method to manufacture components subject to the European Pressure Equipment Directive.

As soon as the CAD data are available, 3D printing is unbeatable in price and enables a procurement time of only a few days. This means KSB can 3D print components that are no longer produced by other pump manufacturers – or that would be very expensive and take months to produce. In this particular case, 3D printing saved three quarters of the costs.

One of the new impellers reproduced by 3D printing

Using fragments of the old Halberg impellers, a new 3D model was created on the computer. In CAD the engineers precisely redesigned the impeller geometry, such as the vane curvature, number of vanes, and outlet width. Based on the operating data on the name plate the original hydraulic performance data was also reproduced exactly.

Continuing to use the aged pump has got some other positive side effects: By commissioning KSB, EAM managed to keep using all existing piping and plant components at the site. This avoided expensive and time-consuming re-planning of the system, piping, condensate collector and corresponding valves.

The new impellers have also enhanced the hydraulic efficiency of all pumps, resulting in a higher energy efficiency, an increased system availability and therefore clear savings regarding the life cycle costs.
More importantly: Reproducing the new parts has given the pump a second life. With sustainability in mind the experts from KSB SupremeServ have long focussed on repairing old pumps – no matter what their type and make – instead of replacing them by new pumps, which is cost- and labour-intensive.

KSB SupremeServ maintains an extensive service network in Europe and in central locations on other continents. 3500 specialists in more than 190 service centres worldwide provide a regional presence for our customers, with short distances, fast availability and expert services.

Our motto is: ONE SERVICE – EVERYTHING YOU NEED

Customer: EAM Natur Energie GmbH

Application: Condensate pumps for power stations

Project data: KSB SupremeServ, 3D printing

Project year: 2020