Heat and dust: energy supply system for indoor crane under adverse conditions

Profile

• What was needed: Pre-assembled energy chains for use in a Heavy-Duty application
• Requirements: Tight installation space, resistance to high temperatures and heavy contamination, trouble-free operation
• Field of application: Steel industry
• Success for the customer: Quick assembly on the crane bridge by delivering the filled e-chains® on transport drums. The very compact chains also do not have to be dismantled or packed for onward transport to the place of use.

At Thyssen Krupp’s hot rolling mill in Duisburg, a double-girder gantry crane plays a key role in handling freshly produced steel slabs. These slabs are later processed into steel strips. The crane is responsible for storing, retrieving, and feeding the slabs into heat-retaining furnaces.

This crane moves along a 500-meter-long track at speeds of up to 120 meters per minute. Its trolley, which carries the operator’s cabin, can travel at 60 meters per minute and covers nearly the entire length of the bridge.

Due to limited overhead space, the entire control system is built into the bridge itself instead of a separate control room. To accommodate this the trolley moves between the two bridge girders instead of above them.

The crane is designed for heavy-duty operation in extreme conditions. It operates in an environment filled with dust and high temperatures—reaching up to 70°C near the ceiling due to the heat from the slabs and furnaces. To ensure reliable performance, all components, including the movable cables and energy chains for power and signal transmission, must be specially engineered to withstand these harsh conditions.

igus® technicians recommended the rol e-chain® 5050RHD for the energy and signal supply on the crane bridge. This e-chain system used for "heavy duty" applications is characterized by reinforced side parts, additional wear surfaces and a pin-hole system that has been reinforced by about 40 percent. As a result, cable weights — in this case 13 kg/m — can be guided and moved reliably over a distance of 15.5 m. In addition, chainflex® cables from igus® were used. A TPE jacket ensures that all cables can withstand the high temperatures in the system.

Based on the special requirements for energy chain and cables, the chains were designed and supplied as pre-assembled readychain® basic systems. The cables had been inserted but not been completely pre-assembled or fitted with connectors. This is because plug-in connectors were unnecessary because the cables are connected to terminals and the cable lengths for such a special project cannot be determined down to the centimeter.

Flexibility is more important in the assembly. Only the fiber optic cables (FOC) were harnessed with connectors in advance.