Next Generation of Thermal Imaging Technology Solves Aluminium Temperature Control Challenges for Operators

LAND^® highlights the increasing numbers of furnace operators who are achieving a competitive advantage by switching to the latest thermal imaging systems to overcome the difficulties of remote measurement of liquid aluminium.

Representing an advance from traditional single-spot temperature measurement methods used for many years, the new generation of borescope furnace technology enables an unparalleled view inside melt furnaces to accurately and continuously profile the temperatures within the furnace without disturbing the process.

Operators in the aluminium sector can benefit from optimised processes, enhanced efficiency and quality, and improved safety after implementing thermal imagers into automated process control systems. This generates extensive amounts of crucial thermal behavioural data that was not previously available to them.

Aluminium is a challenging material for measurement instruments to achieve accurate readings due to several characteristics, including a low emissivity which varies in value depending on oxide layers and type of alloy, preventing direct correlation of the Infrared radiation intensity emitted by the metal with its temperature.

LAND’s advanced radiometric infrared borescope MWIR-b-640 thermal imager with spectral filtering uses a mid-range wavelength of 3.9 μm to achieve a clear, continuous view through heavy smoke and hot furnace atmospheres, overcoming the difficulties caused by reflections from the hotter walls, fumes and particulates, dross build-up and surface materials which impact the measured signal.

With a wide-angle field of view, the LAND camera allows multiple areas to be imaged and measured simultaneously, enabling high-resolution furnace measurement image data to be taken, stored and trended over the lifetime of the furnace to facilitate the early detection of leaks and temperature variations helping to optimise processes.

Additionally, accurate temperature measurement of liquid aluminium is essential for process efficiency to ensure the integrity of the finished product. If the temperature is too hot, this will alter the chemical and physical properties and the casting will not meet the required specifications. If the temperature is too low, the molten metal will not flow into all the cavities and apertures of the casting due to solidification. 

Continuous temperature allows aluminium operators to closely control the process to better plan tapping and pouring operations and to ensure the metal is heated using a minimal amount of energy. Changes over the melt objects can be analysed to predict melt rates and process transitions, while dross formation can also be monitored. 

James Cross, Head of Industry Management at LAND, said “The traditionally difficult process of continuous non-contact measurement of liquid aluminium in pouring processes can now be solved with LAND’s technology. The benefits for aluminium operators are significant, ranging from high-quality casting, reduced product variation, improved process control and quicker development of new recipes and products, to enhanced capabilities to answer demand for high-quality aluminium products while limiting emissions and reducing energy use.

“With increasing quality requirements, we are seeing more companies switch to process thermal imaging systems to provide accurate temperature measurements of the entire metal stock and the furnace interior. As we look to the future, the implementation of thermal imagers into process control systems will be a key factor in enabling a more efficient, optimised and automated operation.”

The MWIR-b-640 is supported by the advanced ImagePro thermal imaging and data processing software. Operators have a clear view of the critical areas within the furnace with more than 300,000 image pixels measuring in the range of 300–1200 °C or 500–1800 °C. Through ImagePro, the performance of the furnace can be monitored to easily identify hot and cold areas, and any uneven heating can be viewed in real time from the safety of the control room. 

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