PRESSURE-FLUCTUATIONS IN PNEUMATIC CONVEYING SYSTEMS

The pressure fluctuations generated in pneumatic conveying of solids in a horizontal piping arrangement have been studied in order to provide a technique for flow pattern identification and control of the pneumatic conveying operation. Practitioners of pneumatic conveying have used flow noise production in pneumatic conveying as a technique to diagnose the operation of such systems. The pressure fluctuations measured were placed in power spectral density function (PSDF) format and related to the flow patterns visually observed. Distinguishing PSDFs were observed for the various flow pattern regimes. The effect of particle size, system configuration, pressure transducer type and acquisition parameters were explored. The analysis was carried out on-line so that control strategies can be employed. The pressure tap spacing did not influence the spectra generated at the various flow regimes. Static pressure transducers proved more reliable for homogeneous and stratified flows detection while differential pressure transducers were preferred for the dune/slug flow condition.