Method and apparatus for the determination of particles in screenings

摘要

The method involves mapping a linear region (25) with optical photocells (30.1-30.102) i.e. photodiodes, where the region is irradiated with light and a measuring cell (4) is arranged in the region. A digital brightness signal is produced from signals of the photocells. A brightness gradient of the photocells over a photocell line (30) is determined from a position of the photocell line and size of the photocell. A value of diameter of a particle is determined based on increase in the brightness gradient and/or alteration of increase in the brightness gradient during a selection cycle. An independent claim is also included for a device for determining size of particles in a particle stream.