Ten years later, this system is still tough and exciting, while also ideal for long-term use. At Tušimice the coal is stored in a long heaps on the periphery of the power plant site, which theoretically could be used to fuel the power station for a full week. To pile the coal automatically on the heap, a 'stacker' is used. To supply the stacker with energy, data and media, the ČEZ Group opted for an energy chain system from igus. Result: 615m travel – a world record.
At Tušimice the coal is stored in a long heaps on the periphery of the power plant site, which theoretically could be used to fuel the power station for a full week. To pile the coal automatically on the heap, a 'stacker' is used, which must be reliably supplied with energy, data and media. Since the stacker is only used in the event of a stop in regular coal production in the lignite power plant, the energy supply system must also always work reliably, sometimes in 24/7 continuous operation, sometimes during a one-month shutdown. The extreme weather conditions in the cold Czech winter were also a special challenge. For example, the cables of the previously used cable drum froze time and again, which could result in repeated failures and unplanned downtimes on the long travel when the system starts up. Accordingly, the customer was looking for an energy supply system that was as resilient as it was fail-safe.
Trouble-free operation in the lignite power plant in Tušimice has therefore been ensured for more than 10 years by an energy chain of type 5050RHD. The 'R' in the name stands for 'rollers'. By using a roller, the coefficient of friction on long travels drops dramatically, when the upper run of the chain runs on the lower run. Thereby, the coefficients of friction is reduced and up to 57 percent of the required drive energy can be saved while moving the energy chain system.
Along with the 615-metre record travel, two more systems are being moved with roller energy chains from igus - one is a 400-metre travel, the other is 150 metres. The two systems supply the 'reclaimer', which removes the coal from the pile and transfers it to the conveyor belt that runs to the power plant.
Inside the energy chains are various chainflex cables from igus, which have been developed specifically for use in energy chains. In addition to the chainflex motor and control cables, an optical fibre cable for data transmission is also used on the 615 m travel. "Bus cables are out of the question for these long travels, as the signal strength would be insufficient," says Frank Schlögel. In addition to the various cables, a water hose is also routed in the chain, which can optionally be heated.
Since commissioning, an electronic monitoring has been carried out on the energy chain systems in Tušimice. This measures the push/pull forces of the chains and can switch off the system if the forces become too high. This can happen when debris enters the system, for example. In recent years, igus has further developed this form of 'condition monitoring' and today offers machine builders modules for monitoring and predictive maintenance as an additional safeguard.