Steel rod coils are transported along a series of hook carriers that run along a monorail system from the wire rod mill to the warehouse. After quality and temperature checks, lift tables on conveyors route the 2.2t, 1.3m diameter coils to the rackstackers. At peak times, the system can handle up to 106 coils per hour. Each coil is positioned by the rackstacker into one of the 4,700 coil slots within bays that are stacked seven high. A number of the bays have heat-shielded racking to accommodate very hot coils.
The twin-mast-designed rackstacker runs freely along rails, guided by top and bottom carriages, enabling the mast’s coil lifting mechanism and telescopic fork attachment to handle the coils. A variable-frequency-drive-operated motor, winches the carriages by the twin wire ropes connected to each side of them. A facility also exists for independent operation allowing hand control and inspection.
A laser is used to measure the rackstacker’s position along each rack. To locate individual bays, a linear position encoder is used, which is attached to the bottom of each carriage for easy maintenance. Prior to pick or deposit, sensors then check whether an individual bay is occupied or empty.
At the highest level, a custom-designed warehouse coil management system coordinates the entire flow of material. Five rackstackers operate in 3 aisles with PLC and anti-collision systems controlling each unit of machinery, including over 100 conveyors, the shuttles and other equipment.
Luxembourg-based CTI Systems, acted as general contractor for the entire automated warehouse project, employing more than 170 people on engineering and production, according to project manager Claude Dunkel. It engineered and assembled all of the machinery itself, except the racking which CTI Systems designed together with a subcontractor. The racking was erected with local contractors under the supervision of CTI erectors.
The warehouse became fully operational in June.
CTI Systems has not yet been awarded the maintenance contract. But “considering the complexity of the installation, CTI Systems may maintain the system on behalf of Corus,” Dunkel said.
Corus Group plc is one of the world’s largest metal producers with an annual turnover of Euro 12bn and major operating facilities in the UK, the Netherlands, Germany, France, Norway and Belgium.
