Pressure Fluctuations – Solt was the first to my knowledge that suggested the idea that the noise generated by pneumatic conveying could be used in diagnostics of the problems which such systems experienced. Dhodapkar and Klinzing (1993) took this idea and applied signal analysis of the pressure fluctuation to such flows in order to predict the flow regimes and operations. This type of analysis could be done on-line in the plant. The results point to very distinct signals of the pressure fluctuations depending if the flow is homogenous in nature of is a moving wavy bed. Figure 5 shows one such signal for stratified flow.
Utilizing pressure measures and other noise analysis techniques has been pioneering by Davies (1987) applying many of his ideas and invention to actual industrial usage.