U Rod linear refractometer for on-line compositional sensing

Abstract

A novel refractometer has been developed for use in on-line compositional sensing in the food and drink industry. The device is designed to measure total amounts of soluble solids in liquid foods such as jams, syrups and pulps. A system is required that is simple and cheap, yet optimised for accuracy of refractive index measurement and linearity. A U Rod is presented as the principal component, the multiple reflections within the U Rod provide a key design feature to reduce the influence of non-total internal reflection and significantly improve the measurement linearity.