Design of a Flow-Through Refractometer for Monitoring the State of Transparent Media with a Cylindrical Insert in the Form of a Vertical Section of a Pipeline.

The problems of monitoring the state of flowing media with a simultaneous change in temperature and flow rate of the medium by more than two orders of magnitude are considered. A design of a flow-through refractometer is proposed for monitoring the state of transparent media in laminar and turbulent flow regimes, as well as at high flow rates and changes in the temperature of the medium by more than 200°C. The developed flow-through refractometer implements a method for measuring the refractive index, based on the principle of parallelism of two beams: the incident and transmitted through a pipeline with refraction at the boundaries of several media. The piping in the form of a cylindrical Plexiglas insert is part of the refractometer design. The design of the optical part of the refractometer with a vertical section of the pipeline eliminates the influence on the measurement of the refractive index of errors caused by multiple reflections of laser radiation from optical elements, the formation of voids or vortex flows in the pipeline. For the proposed refractometer there are no restrictions on the value of the measured refractive index of the flowing liquid, in contrast to the previously used industrial flow-through refractometers, the principle of operation of which is based on the phenomenon of total internal reflection of laser radiation at the interface of two media. The results of experimental studies of various media with the proposed refractometer are presented. [ABSTRACT FROM AUTHOR]