摘要 |
A pollution monitoring device including a fluid sampling chamber (21), a collimated light source (14, 15) directing a light beam (10, 11) into the chamber, a port (23) for introducing sample fluid into the chamber exposed to the light beam, a light detector cell (16) separated or shaded from the light beam and focussing apparatus (17) for directing scattered light produced by the presence of suspended particles and molecules in the chamber towards the detector. The source may be two lasers with co-linear beams or an LED. There is also disclosed a sample area of small diameter in which a light beam traverses the area across the flow path of a sample fluid and a projector projecting scattered light from particles into a light receiving zone of notional conical shape having an included angle of at least 60 DEG , to enable discrimination of particle size discrimination. <IMAGE> |