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Equipped with 4 trolleys, the crane is now fully operational in Frederiksværk, DK

The Final Acceptance Certificate for the 80-t Automatic Gantry Crane was issued by NLMK Dansteel plant to Danieli Centro Cranes.

The crane is custom-designed and fitted with 4 trolleys, each one equipped with a 40-t magnet lifting beam. Thanks to this configuration the crane can handle a wide range of plate dimensions (3700x1500x20 mm to 31800x4200x260 mm), with temperatures up to 550°C.

The crane works in automatic mode in a restricted area ensuring that all automatic movements are safely performed, including:

• picking up plates arriving from cooling bed;
• temporarily storing them in a slow cooling area (yard); and,
• feeding the roller table that moves the plates to the heat treatment furnace.

In case that one of the safety preconditions is not met for some reason (e.g. the safety gate is open) or maintenance operations are needed inside the area, or, even if it is necessary to store the plates in two storage areas in the adjacent bay, it is always possible to operate the crane manually using radio remote control.

A laser scanner is installed on each leg of the crane to detect the presence of an obstacle on the crane rails. To further increase the safety level, the crane legs are equipped with mechanical bumpers that prevent damage to people and things in case of laser scanner failure. When one of these is activated, a signal is sent to the PLC to interlock the machine movement.

The crane also is equipped with an anti-collision device in order to interact with the other cranes in the same bay.

A remote pulpit for mission management and crane condition diagnostics is located on the ground and communication is done using a wi-fi system. The crane receives assignments inserted by the operator and is then able to work without any additional commands.

Once the mission is defined, the crane scans the area with five 2D laser scanners installed under the crane girder and, by reading the exact dimension and position of the plates on the cooling bed it adjusts its X, Y, Z position and the optimized configuration of trolleys and hoists to be used for the mission is defined automatically.

In addition to the PLC installed in the crane's electrical room, a second safety PLC is installed on the ground to manage the communication with the rest of the plant (the cooling bed and the roller table). The two PLCs communicate through a dedicated wi-fi system.

The interface between the crane, the cooling bed and the roller table is managed by two levels of automation.

• L1 manages the interlocks between the crane and the cooling bed and the roller table, respectively.
• L2 provides the data to allow the crane to execute the missions in a fully automatic mode and, as a result, the plates are tracked along the whole path.