Apparatus for measuring particle size distribution by making use of laser beam diffraction and scattering

摘要

Laser beam L is scattered by particles in the sample cell 1. Photosensor assembly 33 detects forward scattered light and assembly 5 detects sideward and backward scattered light for the purpose of increasing the precision of measurement. Both the photosensor assemblies are temperature-monitored by sensors 6 and 7 to prevent erroneous measurement due to small temperature-dependent zero-level shifts of photosensors used in the photosensor assemblies. If temperature variations of or a temperature difference between the assemblies exceeds a predetermined value, an alarm signal is generated with the measurement interrupted automatically.