Infrared thermography for detecting the deposit nature in steel water pipes

The formation of calcareous and rust layers in water pipe networks poses a significant technical problem. In this work, we studied by infrared thermography, the possibility of evaluating the deposits nature frequently found in steel water pipes such as rust and limestone. In the one-dimensional case, we calculated by simulating the thermal effusivity of deposits in steel water pipes from their surface temperatures. We have considered the case of a semi-infinite solid composed by a finite thickness layer over the top of a semi-infinite deposit. The results can be applied in the nondestructive inspection for determining the deposits nature in the water distribution pipe networks steel. . 1. Introduction Deposition of calcium Carbonate scale and rust in the water pipes becomes a serious problem for several industrial installations, it can lead to important technical and economic consequences: clogging and diameter reduction the water pipes, increase energy consumption [2,4]. Knowledge of the nature of these deposits allows with a non-destructive method to eliminate them or intervene by industrial processes upstream to prevent their deposit. Therefore, it is necessary to develop methods of prevention to identify the layers nature formed in the inner surface of steel water pipes. The active technique using an infrared camera can be used for several applications such as diagnosis of fouling and clogging in pipes, detection of cavitation erosion, inspection of inner surface of side walls and cracks developed in the films which protect structures etc. ... Based on the analysis of the one-dimensional theoretical solution of the heat conduction equation in the case of a solid compound of a finite layer associated with a semi-infinite substrate layer and subjected to a constant heat flux. We will propose a method for estimating the thermal effusivity of rust and calcium carbonate layers formed in the inner walls of steel water pipes.