VORRICHTUNG UND VERFAHREN ZUR BESTIMMUNG VON PARTIKELGROESSENVERTEILUNGEN MITTELS STREULICHTMESSUNGEN

摘要

In order to determine fine particle size distributions by scattered light measurement, a collection of suspended particles is exposed to coherent light, the scattered light pattern reproduced on the photosensitive multi-element detector of a recording device is converted into electric signals and the particle size distribution is calculated by a computer from the digitalized luminosity signals. In order to simplify the design of the device and to improve the precision of the calculable particle size distributions, the recording device is a video camera and the computer calculates the particle size distribution from the luminosity signals of the pixels of the video image by solving a Fredholm integral equation. The video camera is preferably a CCD camera. In order to modify the light exposure intensity, a rotating disk with grey filters that reduce the light intensity in various degrees is arranged in the path of the measurement rays, or the video camera is provided with an electronic shutter having a variable exposure time. Various particle size fractions may also be detected by modifying the angle between the angle of exposure to light and the optical observation angle.