On-line Nonintrusive Measurement of Particle Size Distribution Through Digital Imaging

This paper presents the further development in the design and implementation of an innovative optical instrumentation system that can measure the size distribution of particles in a pneumatic suspension. A low-cost charge-coupled device (CCD) camera is used to capture the images of the particulate flow field, which is illuminated by a low-cost laser sheet generator. The particle size distribution is then determined by processing the particle images through the use of novel processing algorithms. Experimental results obtained on a small scale particle flow test rig have demonstrated that the system is capable of measuring the size distribution of pneumatically conveyed particles with repeatability better than 1% for a volumetric concentration up to 2%. A relative comparison is made between the on-line imaging technique and the widely accepted laser diffraction based particle sizing method. In addition to laboratory scale testing, results obtained in an industrial setting are presented and compared favorably with off-line reference values