Optical measurement head for determining optical density - has transmitters and receivers separated by aperture with dividing walls of different thicknesses

摘要

The suspension measurement head consists of two optical transmitters (12, 13) and two receivers (14, 15) arranged in a rectangle. All units are embedded in a translucent material. The dividing walls (21, 22) are of differing thickness. One wall (22) is a reference. Measurement is performed by alternating between pairs of transmitter-receivers. Reflected light from the suspension in which the head is placed varies in intensity according to the concentration of contaminant and light path length. USE/ADVANTAGE - Measurement of high concentrations of suspended material. Avoids problem of using narrow channels for insertion loss method using transmitted light. Cross comparison calibrates transmitters and receivers.