# Investigation of Inner Lining Loss and Correlation with Steel Structure Quality in Rotary Kilns
## 5 Conclusions  
The purpose of the research was to establish a relation to the ovality of the steel structure and the amount of material that was lost from the inside lining of the rotary kiln. It was determined how much of the inner lining had been lost by making a comparison between the ideal condition (one in which there was no damage) and the real condition (one that was measured using a laser scanner). According to the results of the research, the prediction that the perpendicular part of the furnace would experience consistent wear was erroneous. The investigation indicated that there were considerable variances in the amount of loss detected between sections. The joint noticed the greatest loss, which measured up to 52 mm, while the face of the bricks experienced a loss of 35 mm and 12 mm elsewhere. The ovality of the rotating kiln ranged from minus two centimetres to plus two centimetres and was measured outside the rotary rings. The location of the centre of the cylinder was derived from the observed cylinders of each steel strip, and the axis of the rotary kiln was located using a method that minimised the sum of the squared deviations. The eccentricity reached a peak value of 18 mm at its highest point. The ovality of the steel structure was measured using a 2 cm grid containing 2.1 million points. Each point was given a value from this grid so that the correlation between the loss of internal lining and the ovality of the steel structure could be determined. Filtering out null data and points with maximum ovality values and the loss of internal lining led to a reduction in the total number of points, which was reduced to 270,000. According to the study findings, there is a significant link between ovality and lining loss, with Pearson's correlation coefficients ranging anywhere from 0.38 to 0.57 depending on the portion of the furnace analysed. The preciseness of the scanner as well as the reflectivity of the smooth shining surface of the slider ring both have a significant impact on the final output. In summary, the research reveals important information on the internal lining loss of the rotary kiln and the correlation between this loss and the ovality of the steel structure. This study demonstrates both the importance of properly cleaning the brick lining from \begin{table}
\begin{tabular}{c c} \hline
**Length of Rotary Kiln** & **Pearson Correlation Coefficient** \\ \hline
6–26 m & 0.38 \\
26–42 m & 0.47 \\
42–56 m & 0.57 \\
56–74 m & 0.36 \\
74–90 m & 0.44 \\ \hline \end{tabular}
\end{table} 
Table 2: Pearson correlation coefficient estimated on parts of rotary kiln. time to produce accurate measurements and the limits of the laser scanner in identifying wear on the shining surface of the travelling ring. Both of these issues are highlighted in the study. The results of the study have the potential to be used as a foundation for developing maintenance and repair techniques for rotary kilns, which can ultimately result in greater productivity and longevity. Future work will focus on the evaluation method of period measurement. Each year, the rotary kiln will be measured and the actual results will be compared with previous results. Changes in ovality and lining loss will be monitored and examined with current results. Thermometers also monitor the rotary kiln of this paper, providing real-time insights into the distribution of heat and potential hotspots. Thermal measurement will be added to analyses of the correlation of ovality and lining loss. Conceptualisation, D.Z. ; methodology, D.Z. ; validation, D.Z. and J.V. ; formal analysis, D.Z. ; investigation, J.V. ; resources, D.Z. ; data curation, D.Z. ; writing--original draft preparation, D.Z. ; writing--review and editing, D.Z. ; visualisation, K.P. ; supervision, K.P. ; project administration, K.P. ; funding acquisition, K.P. All authors have read and agreed to the published version of the manuscript. This work was supported by the grants SGS23/052/OHK1/1T/11 and SGS23/050/OHK1/1T/11 funded by CTU Prague, Czech Republic. Not applicable.