Material level-interface control system
 An optical temperature compensated material level-interface sensing and control system which comprises an insertion probe (10), control circuitry and a housing enclosure (72). The probe (10) makes use of a pair of emitters and detectors, in which one pair is positioned across a channel (26) through which material passes and the other pair are mounted in a sealed tubular bracket. The first emitter and detector pair are optically active with respect to sensed material, and the other pair is optically isolated, but thermally active. The resulting signal is a function of the material's linear coefficient of absorption with the thermal influence being effectively canceled out. The outputs of the control circuit are user selectable and changeable. The device is able to detect material presence and identity for use in interface-level control applications through a wide range of pressures and temperatures in industrial applications. 
G Y
G01F Y10S
inventional additional
Kevin Steven
Lyons Lyons