Evaluation of an indirect slag level measurement for liquid steel

This paper describes an indirect level measurement for slag in the refinement process of liquid steel. Slag and slag foam can pollute plants and therefore lead to high costs due to cleaning and maintenance work. Knowledge of the slag level during production could help to prevent this by taking counter-measures at an early stage. We present a measurement strategy which is based on the radiated heat of the hot material. Sensors are placed in the cooling tube of a plant and measure the slag and steel level based on the increase of the cooling water temperature. To reduce the cabling effort an extensible sensor chain was used. Addressable sensors allow a location based temperature evaluation over a ladle filled with liquid steel. We investigated different electrical isolations and carried out simulations on the housing to achieve a low thermal resistance that allows the detection of temperature changes in the cooling pipes despite the massive amount of cooling water.