Some embodiments of the invention provide an improved spectrometer that measures light emissions and/or reflection from a non-solid material that flows through a system of pipes. This spectrometer is designed to fit into a standard pipe system. The material flows past a distal end of the spectrometer...http://www.google.fr/patents/US7099012?utm_source=gb-gplus-shareBrevet US7099012 - In-line spectrometer
