In the hall aisle of an integrated smelting plant of the customer a crane with lifting capacity of 50 t is available which is working as individual crane. It performs 95 percent of all incurring cargo-handling services and of the maintenance jobs in the cold rolling mill. Furthermore the crane is used for transport and interim storage of the incoming coils and it is operated with a bundle grab. The coil and the bundle grab are weighing 30 t altogether. The transport of the coils is estimated to be performed in 24.000 loading cycles per year and it will be carried out in three-shift operation. The requirement is: The crane, equipped with a radio remote control system, will continue being used by the maintenance staff for transport of motors and for small repairs. Ambient temperatures of up to 50°C and in an oily atmosphere due to emulsion mist from the mill stands cause harsh environmental conditions. The objective of this project was to equip the existing crane with new end carriages and to increase the speed of the main hoist in order to adapt it in an optimal way to its area of application.
The end carriages comply with state-of-the-art technology and they have been adapted to the existing bridge girders. Their span was adapted to 34 m. The running wheels are without flanges. The bridge girders could be re-used with all the components mounted on them and they could be adapted to the new end carriages. Furthermore the crane was equipped with a new cable drag installation with flat cables. The old crane driver’s cabin was equipped with a new air conditioning unit.
In the course of modernisation of the electrical system the lifting speed was increased and the access detection system mounted at the access ladders of the crane was renewed. The trolley is now equipped with a main hoist and an auxiliary hoist and with a motorized cable reel for the coil grab’s control and energy supply. In the course of the reconstruction measures the electrical equipment of the trolley was modernized and adapted. After its modernization the crane is perfectly suited for assuring continuing safe productive operations in the hall.