Cases07 October 2020
Locked stop drilling and tamping machine Blast furnace B
John Kennedylaan 51
Steel production usually starts with the smelting of iron ore in a blast furnace. A blast furnace is an installation in which iron ore and carbon are smelted and mixed. They are heated until they melt so much that chemical reactions create pig iron melts, in which a certain percentage of carbon is dissolved. It is then tapped. When enough pig iron melt has accumulated at the bottom, the blast furnace is opened at the bottom and the pig iron flows out through the tapping hole. There, it is collected in mixers, which are transported to the steelworks for further processing. When all the hot metal has been tapped from the blast furnace, the tapping hole is closed again.
When tapping hot metal, the drill and tamping machine is indispensable. These robust machines do no more than their name suggests, but given the challenging environment and high temperatures, the right know-how is needed to control the machines correctly.
During the renovation of HOB in 2020, ArcelorMittal decided to entrust the new safety concept for the 2 robust machines to CPA. What was previously mandatory with LOTO locks has been replaced by the much more user-friendly ‘Locked Stop’ principle, where the installation can be easily secured by means of a bistable push button.
The safety of these machines can be viewed in two ways. Firstly, it must be ensured that all power sources (electricity, pneumatics, hydraulics) are switched off when working on the machines or performing any operator action. But equally important is the proper operation of the machinery to ensure that the operation of the blast furnace is not disrupted. Indeed, opening and closing the blast furnace is at least as important to avoid other dangerous situations at all times.
For this reason, in addition to the 2 standard situations (in use or secured), several emergency procedures have also been worked out that can be triggered quickly if the correct actions are taken. This is to override the safety equipment, after it has first been checked by human control. This may seem contradictory to a safety concept, but it is designed to cope with the challenging situation at all times without compromising staff safety.
Due to the circumstances, it is not possible to integrate a full-fledged screening fence. Therefore, an optimal indication of the current situation was chosen. Large lights above the facilities indicate whether the plant is safe or in operation, while the necessary sound signals are used to quickly alert the personnel present in case of any anomalies. A useful additional feature is the use of LED projection to delineate the safe zone, so the operator always knows where it is safe to move and where it is not.
Indicating safety by means of large lights at top.
Thorough safety concept to achieve the desired Performance Level (PLr).
LED projection to indicate desired zone.
10 February 2021Safety concept for an overhead crane with wireless ProfiSafe