"We have extreme conditions on site"

igus® in conversation with the head of maintenance/electrical engineering at AVA Abfallverwertung Augsburg GmbH Dipl.-Ing. Werner Kretzinger

At the beginning of the 1990s, a facility was built on a 23.5-hectare site in Augsburg, which consisted of a modern composting plant. In the composting plant, quality compost is produced from organic and garden waste and other biodegradable waste. The composting process takes place in the composting hall. With the help of the turning machine, the Wendelin, as the name suggests, the compost is turned so that the "biology "gets to work". Depending on the decomposition phase and degree of rotting, individual conditions are created in the individual windrow sections in terms of biopopulation, metabolism, temperature and moisture. The composting process is completed after around ten weeks, although the conditions on site in the composting plant are extreme. The organic waste rots in a closed hall. Vapour and heat are generated. Temperatures of up to 40 °C and a humidity of almost 100 % are the norm. During operation, the hall should only be entered with a face mask. In addition, there are all kinds of substances in the air that affect the technology. For example, significant concentrations of ammonia and organic acids were found in the air of the rotting hall. Slimy biofilms have formed on all surfaces, including the energy supply lines. The pH values on these surfaces are around pH5. "We can't use steel in the composting hall. Only 316 stainless steel can withstand the conditions on site," says the maintenance manager. The plant runs day and night, so the demands on the durability of the components are extremely high.

Since the composting plant was commissioned, energy supply systems from igus® in various lengths and designs have been in use in the shifting system, the so-called Wendelin.
The Wendelin has a longitudinal chain and a cross chain in the plant. In addition, there are two further chains in the entry for transporting and distributing the organic waste in the first windrow, which means that a total of eight energy supply systems are in use. Apart from the longitudinal travel, only 'Rol-E Chain' roller energy supply systems from the modular and robust 'E4/4' system are used.
Roller energy chains really come into their own when it comes to long travel distances, high speeds and high cable loads.
In contrast to sliding e-chain®, the necessary drive force can be reduced by 75 %. The coarse and coarsest dirt particles, especially on this system, generally lead to increased abrasion. The even rolling operating mode minimises the rolling resistance and thus the wear of the chain. Their service life increases considerably.
In addition to the roller energy supply systems, chainflex® cables, guide troughs for the long travel distances, separators and strain reliefs from igus® are also used. The unshielded control cable 'chainflex® CF 5' is located in the energy supply system. Thanks to its structure, with a gusset-filling extruded inner jacket and the PVC-outer jacket, the series is suitable for the highest loads.