system is subject to the person-to-person variations and similar problems associated with any observer-based judgment, e.g.: concentration and awareness level, reaction time, etc.

The theory behind the detection system of Infra Red Camera Based Slag Monitoring & Detection System is shown in the graph where there is a significant difference in emissivity of the slag and steel at higher wavelength. The long wave IR camera used for slag detection system detects this difference to calculate the slag percentge in the molten steel.

1. Background of the Invention

This is the invention in the field of automatic detection of slag percentage for basic oxygen furnace to maintain minimum slag in the ladle. This improves the quality of steel by controlling the slag percentage utilizing machine vision control system.

Minimizing the outflow of converter slag into ladle is one of the fundamental preconditions for improved efficiency of the converter slag in ladle could raise these problems:

• Slag layer hinders alloy and conditioner additions.

• High levels of FeO and MnO results in high Oxygen content of steel leading to increase processing time and treatment costs.

• Phosphorus and silicon reversion occurs.

• Poor ladle desulpherization.

• Poor yield.

• High inclusion formation.

• Increased risk of caster nozzle clogging.

• Ladle refractory layer wear.

• Increased consumption of Aluminum.

• Due to presence of slag, steel quality suffers.

2. System Overview

We are going to use the Non contact type-INFRARED Thermal Imaging technique to stop the flow of slag into the transfer ladle.

The difference in emissivity between the steel and slag results in slag displaying significantly higher apparent temperature than steel when seen by the thermal imager.

This technique has its various advantages over other methods:

• Its a non-contact type method and independent of operator involvement, thus safer compared to other techniques.

• Low maintenance Solid-state camera.

• Adjustable threshold is available which the operator can set.

• Automatic Control of vessel tilting.

• Accurate detection independent of charge weight.

• Improved Yield.

• Steel purity increases.

• Provide tap termination consistency.

• Images can be stored and analyzed at a later date.

• Reduce the number of slag related non-conformance heats.

• Increase operator response time and consistency.

This system will reduce Aluminium consumption, downgrading, recharge and Fe-Alloy consumption.

The overall system has been shown in Fig. 1.

When the molten steel is poured from LD Vessel to Collecting Ladle, Slag pours along with the Steel into the ladle. To improve the quality of the steel, slag percentage should be controlled out during pour into the collecting ladle. To avoid slag carrying into the ladle, flow of molten steel is required to be monitored to detect the slag percentage into the molten pouring metal.

Thermography principles are applied to see the object through IR camera. By using the infrared imaging techniques, the slag can be monitored and detected out separately from metal.

Therefore, a reliable Slag Monitoring and Detection System (SMS) is developed. This system is based on thermal theories to identify the different metal based on the temperature radiation of each metal. This system works with Infrared (IR) camera that deals with the thermal image of the object. SMS is capable to identify the steel-slag transition under varying operating conditions. Influencing factors for the measurement principle include:

• Steel tap temperature differences.

• Tap hole changes that affect mass/energy and emissivity levels.

• Changes in air humidity that affects the transmission of infrared radiation.

• Radiation from other sources.

SMS System recognizes and suppresses these influences.

SMS achieves this by directing the infrared camera signal to an industrial PC, where the image processing is done. This system solution allows the automatic identification and tracking of the tap stream.

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