Abstract
It usually takes time to measure the particle size and/or size distribution. Using a novel laser particle sizer based on Fraunhofer diffraction theory, the measurements are done in situ and rapidly.
The purpose of this report is to investigate the effects of measurement conditions on the representative particle size XR and index W in the Rosin-Rammler equation, that is, spatial number density, sampling position from a Fourier transform lens and so on.
By the use of glass beads of a known size, the results of measured values, XR and W, were compared with the value from microphotograph method. These experimental results indicated that the upper limits of spatial number densities in this experiment were, for example, 8×104 particles/cm3 for beads below 44μm sieve and 103/cm3 for 177μm-250μm respectively, and the most suitable sampling position for satisfactory accuracy was within a distance from the lens equal to the focal length of the Fourier transform lens. Setting three different focal lengths of the lens for the same sample, the results of the measured values XR and W agree fairly well with each other.
