Compact hemispherical refractometer for measuring substance concn in solutions - using infra red rays totally reflected around hemispherical optical glass immersed in solution for measurement

摘要

A hemispherical body of optical glass (1) is immersed in a solution whose concn is to be continuously monitored. A light emitting diode (6) with lens (7) projects infra red rays (4) on to the flat surface (3) of the semi-sphere. The glass of the semi-sphere is chosen such that at the threshold concn of the solution there is total reflection which is measured by a phototransistor (8) sensitive to infra red rays. If the concn increases the reflection around the hemisphere is diminished and the reduction is sensed by the phototransistor (8). USE/ADVANTAGE - In chemical and food industries. The refractometer is compact, reliable and very sensitive.