C-DRONE GUIDE · 31 JULY 2026
Industrial rotary-kiln drone thermography: shell, refractory, hot spots, price
A cement rotary kiln runs continuously at very high temperature: inside, a refractory lining protects the steel shell from the firing heat. When this refractory wears or detaches, heat abnormally reaches the shell and creates a hot spot — an early warning of a serious incident, up to shell deformation. Monitoring shell temperature is therefore a major kiln-operation concern. The drone, with a thermal camera, maps the shell from outside, while running, without scaffolding or shutdown: it complements fixed monitoring and extends the view to zones poorly seen by inline scanners. Here is what it brings, its limits, and prices observed in 2026.
Published on 31 July 2026, reviewed on 15 August 2026 — regulations in force as of August 2026.
The shell tells the state of the refractory
The principle is physical and well established: the surface temperature of the steel shell reflects the state of the refractory inside. Where the brick is sound and the protective coating present, the shell stays relatively cool; where the refractory thins, cracks or detaches, a hot spot appears. Mapping shell temperature therefore reads lining wear indirectly, without opening the kiln.
This correlation is documented. A study by Le Guen and Huchet published in 2020 in the Quantitative InfraRed Thermography Journal links the wall temperature measured by infrared to the internal thermal behaviour of a rotary kiln (see the study on Google Scholar). The inline shell-scanner principle, an industrial reference, has also been validated: a study by Yi, Xiao and Song published in 2013 in Measurement describes an infrared scanning system of an alumina kiln shell to infer the coating shape and anticipate the operating state (see the study on Google Scholar). The drone applies this same physics with a mobile camera.
What the drone adds to fixed monitoring
Many kilns have an inline shell scanner continuously sweeping one generatrix of the kiln. It is the reference tool, and the drone does not replace it. But the fixed scanner has blind spots: zones hidden by riding rings, tyres, fans; upper parts of the shell; kiln portions poorly covered by a single sensor. The thermal drone completes the coverage: it orbits the shell, films the scanner's hidden zones, and documents a hot spot from every angle.
It is also valuable for one-off diagnosis: after a hot-spot report, before a scheduled shutdown to target refractory zones to replace, or on a kiln without a fixed scanner. The radiometric camera quantifies each zone in temperature, with a supporting visible image to place the anomaly on the real kiln. It is the same approach as our electrical-panel thermography guide, transposed to the high-temperature structure.
Flying around a running kiln: framework and limits
Flying around a rotary kiln is prepared like any industrial-site job: coordination with kiln operation and maintenance, accounting for hot-air flows and thermal turbulence around the shell, safety distances from rotating parts (tyres, rollers, drive gear), and airspace checks on Géoportail — a cement plant is often in a constrained zone. The thermal camera must be radiometric and calibrated, and the shell emissivity (oxidised steel, sometimes painted) correctly entered so temperatures are usable.
The limit is clear and must be stated: the drone provides an instantaneous, complementary thermal map; it replaces neither continuous inline monitoring, nor the refractory specialist's judgement on relining, nor the mechanical diagnosis of the shell. It is one more mobile eye, valuable where fixed sensors do not see.
Prices observed in 2026
Ranges observed in 2026 (excl. VAT):
- Thermal mapping of a kiln shell (thermal + visible flight, geolocated hot-spot report): €700 to €1,500.
- Targeted diagnosis after a report (hot-spot zone from every angle): €500 to €1,000.
- Pre-shutdown campaign (full mapping to target refractory relining): €1,200 to €2,500.
- Periodic monitoring (regular passes, comparison of hot-spot evolution): quoted.
The flight is scheduled with kiln operation. Our thermal imaging drone page presents the service; request a quote stating the kiln type (cement, lime, other), whether an inline scanner is present and the goal (monitoring complement, diagnosis, shutdown preparation).
Put it into practice
- Drone aerial thermal imaging: rates and cities covered from €500
- Aerial thermal imaging in Dijon Bourgogne-Franche-Comté
- Aerial thermal imaging in Le Mans Pays de la Loire
- Aerial thermal imaging in Perpignan Occitanie