Measurement by diffraction of the size of substantially spherical particles, particularly opaque drops in which an optical arrangement is used to determine particle sizes and concentrations

摘要

Device comprises optical dividing and separating apparatus (46, 49, 50, 51) for receiving light diffracted by the particles illuminated with a light beam, separating it into concentric annular zones, and concentrating the diffracted light corresponding to each zone into separate points (24, 26, 28). The levels of luminous intensity of the points are then used to determine particle size. The initial angular pattern of the concentric zones is selected in accordance with a distribution optimizing discrimination between drop dimensions.