Design and development of fiber optic sensor for measurement of purity of ethanol

Abstract

Pure alcohol (ethanol) has number of applications in automobile, chemical and pharmaceutical industries. Fiber optic sensor has widespread use due to its non contact type measurement in retro reflective configuration. This paper proposes non contact type refractometric fiber optic sensor for measurement of purity of alcohol manufactured in distilleries. This refractometric based sensor shows variation in the received light intensity with variation in water content of ethanol i.e. purity of alcohol. The sensor is studied and analyzed by performing simulation based on mathematical model developed using ray tracing technique. The sensor is fabricated and tested by preparing samples in the laboratory. The refractive indices are later measured using Abbe’s refractometer having the resolution of 0.001 in white light. Field tests are also carried out at the local distilleries. Experimental results show good agreement with the simulated results as well as with the conventional methods used in industry for measurement of the purity of alcohol. The sensor shows linear variation in the output voltage with the variation in alcohol purity of alcohol from 90% to 99%. The repeatability of the sensor is checked by repeating the experiment 60 times for each value of purity.