Abstract
A new approach is proposed for direct measurement of the aerodynamic diameter of particles entrained in a gas. A probe, which can be a pitot static tube, is inserted into the flow. The velocity of each particle approaching the stagnation point is measured, for example by laser Doppler anemometry using a single optical fibre within the probe. The particle size distribution and concentration can be built up from a succession of single particle measurements. The instrument could be used to measure the efficiency of gas cleaning equipment, or to detect surges in particle size or concentration.