Effect of Build-ups on Ladle Wall on Acoustic Signals in Gas-Stirred Ladles

Acoustic signals generated during industrial processes have potential to monitor and provide information about the process parameters. The effect of build-up on the ladle wall on the sound signal was studied on a cold model gas-stirred ladle using an array of four microphones. Power spectrum analysis of the recorded sound showed 2200 to 3200 Hz to be an effective frequency range to detect the presence of build-up on the ladle wall. The amplitude difference in the signals of microphones 2 and 4 (located near and far from the build-up, respectively) was observed to be greater at thin oil levels. Thick oil levels were observed to limit the detection of the build-ups in the ladle. A peak shift in the frequency range 800 to 900 Hz were observed to provide the information about the variations in the oil layer heights in the ladle. The experiments demonstrated that multiple microphones can detect the presence of build-up on the ladle wall more effectively than a single microphone. This technique can potentially help operators to detect amount of stirring as well as the build-ups on ladle wall.