In process measurement of particle size distribution

A new principle of particle size distribution measurement is described. We analyze the acoustic emission signal generated by a flow of particles impacting on a fixed obstacle. Changes of the power spectral density of the signal are well correlated with the particle size distribution. Our method was successfully used for measurement of particle size distribution in the range from 1 mm to 10 mm of ferrous sulphate monohydrate in a real chemistry process. Particles were measured at the output of the dry kiln (temperature 150-200/spl deg/C, mass flow 4 tons/hour), where it is not possible to use any other known principles such as particle vision, laser diffraction analyzers, ultrasonic analyzers, focused-beam reflectance measurement etc.