Opacity measurement in non-uniform dispersions - using light source and receiver with null point drift suppression circuit

摘要

The opacity measurement device is for non-uniform dispersions detects sold opaque objects in transparent media with a light source and photosensitive receiver on opposite boundaries of the medium, e.g. the walls of a boiler flue, and with an indication or print unit. It is designed for simple economical construction and reliable operation with a considerable reduction in null point drift w.r.t. known devices. Only the alternating component of the signal received by the photoresistor receiver is processed. The receiver is supplied from a stabilised source via a resistance. The receiver signal is amplified and rectified before being displayed.