FB doubles the service life of Swiss biomass CHP plant’s chain conveyor
Biomass combined heat and power (CHP) plant IWB Basel in Switzerland was unhappy with the service life of the drop forged link chains and sprockets on its infeed scraper conveyor. Our sister company FB Ketten Austria solved the problem – and reduced operating costs during the process.
Before FB engineers stepped in to help, the service life of the drop forged link chains and sprockets installed on the infeed scraper conveyor at the IWB Basel CHP plant in Switzerland was a maximum of three years. Corrosion is one of the most common problems at biomass plants, due to the high moisture content of the material conveyed, but IWB Basel’s chains were already designed with corrosion-resistant stainless steel pins. Instead, the main issues were heavy wear on the sprockets and significant chain elongation.
Our sister company FB Ketten knew IWB Basel well, having re-equipped the hopper discharge with drop forged link chains twice since 2012, so together with plant manager Ernst Kundert began to look for a practicable solution. The first step was to tackle the wear on the sprockets.
FB Ketten improved the material quality and swapped the standard design for a reversible alternative with symmetrical teeth that can be rotated 180° to double their working life. The material change immediately increased the sprockets’ resistance to wear, while the new design distributed the load more evenly. This lengthened the service life of the sprockets and reduced operating costs – but FB Ketten’s optimisation didn’t stop there.
Since FB Ketten had already introduced higher quality drop forged link chains in 2012, simply improving the quality of the material was not a quick fix that could also be applied to the chain. FB engineers investigated the cause of the wear and tested numerous chain options. The final choice, installed in June 2019, was FB rEVOLUTION scraper chain.
No conversion costs
FB rEVOLUTION scraper chain combines the benefits of wear-resistant drop forged link chains with the fatigue strength, wear resistance, stability and operational safety of modern conveyor chain with welded pins and bushes. The chain is also 7% lighter, helping to reduce material and energy consumption for the sake of the environment, but because it has the same functional dimensions as drop forged link chains, only minor adjustments were required to IWB Basel’s conveyor, eliminating any conversion costs.
Almost 50% less wear
In the time between two planned maintenance stops, the FB rEVOLUTION chain showed a 47% decrease in wear compared to the original drop forged link chains.
The design allows more space for welding, meaning the flights could also be reinforced, eliminating the potential for bent scraper flights. The FB1000TH link plates are much better for welding than case hardened drop forged links.
FB Ketten was very pleased with the outcome of the project and will continue to measure the chain and check it for wear once a year. Based on the measurements, the team gives IWB Basel an estimate of the maximum service life of the chains and sprockets, helping to plan maintenance work and spare parts procurement. So far the service life of the FB rEVOLUTION scraper chain is expected to be double that of the old drop forged link chain, saving IWB Basel both time and money.