PROCESS CRANES | TECHNOLOGY REPORT
R Transport by road...
order – the largest in fact, in its 87-year history. It is also for a steel company, in this case for Thyssenkrupp Steel Europe. The order, worth EUR 14 million, is for a double-girder ladle transport crane with a 40m span and 390t capacity. This is the largest double-beam crane that the company has ever built and is currently in the final stages of installation. The crane is to replace a 360t crane built in 1974, which over the years had been upgraded to carry 380t with a lifting speed of 3.5m/min, but which is no longer adequate. The new crane will have a higher capacity and, at 10m/min, over twice the lifting speed. It will operate as the central crane in the casting hall in Oxygen Steel plant 2 at Thyssenkrupp’s Duisburg Beeckerwerth foundry, where almost 70 ladles of molten metal are lifted every day; it therefore had to be designed for an ambient temperature of 60 degrees and for the transport of flammable masses according to DIN EN 13135 and DIN EN 14492/2. The specification documents run to 180 pages. The ladle crane has a main hoist with 40:4 sheaving and a sliding mechanism on the trolley for auxiliary lifting hooks. The hoist is rotatable and equipped with very precise weighing sensors. A special feature is the sensing system in the hooks: which has two sensors, set at an angle to each other, to check the positioning to ensure that the casting ladle lies safely in the hook
40 | June 2021 |
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mouth before the start of the lifting process. Only then is the lifting movement released and free to move. The crane is the central one of three
cranes located on the same runway, which gives it an essential strategic importance. It is the only one of the three that feeds ladles from the continuous casting system to the rotary towers; in other words, if the crane fails, the entire steelworks stands still. Failure is therefore not an option. Hence redundancy has been built in to all the drives. In the event of any motor failure the crane can still be driven at half speed. Nor does a rope failure cause a load crash, as a transfer shock is generated which is hydraulically cushioned by a rope lock device. A large number of redundancy mechanisms are also provided in the switchgear to ensure high availability of the crane.
SPECIAL OBSTACLES AND STICKING POINTS The pandemic presented a particular challenge to completing the order. Appointments with the customer, such as talks over the drawings, were only possible virtually. Purchasing faced supply-chain issues, for example with acquisition of the custom-made special transmissions. Nevertheless, Kranbau Köthen was able to keep the agreed delivery date and delivered the crane to Duisberg on time at the end of April 2021.
Transport of such a large crane of course
was not easy. From Köthen it went by truck, to the river-port of Aken. Route tests and permits – including for crossing rail lines – were needed; road signs, streetlights and traffic lights were dismantled and overhead lines had to be lifted. Steel plates were laid to protect pavements. Eight conveys set out, over several days, at 10pm to reduce
R ...and by water
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