Optical particle sizers for on-line applications in industrial plants

Abstract We present three optical particle sizers properly conceived for different on-line applications in industrial plants. The first one is a diffraction-based particle sizer utilising an innovative optical scheme that allows the instrument to operate at very low particle concentration regimes (i.e. at extinction values as small as 10 −5 ) in the size range 0.9–90 μm. The second one is based on the same principle of operation, but has been designed with a different optical configuration that makes it suitable for the characterisation of high concentration particle laden flows (like for e.g. pulverised coal downstream of the grinding mills) in the size range 3–300 μm. The third instrument is based on a multi-wavelength extinction technique and provides measurements over long optical paths (up to 10 m) in the 0.1–3 μm size range.