Abstract: An optical probe apparatus (10) is for testing physical properties of a fluid (F) such as turbidity. The apparatus comprises a probe assembly (16) removably insertable into the fluid. A photometric light source (12) generates light and fiber optic cables (14) transmits light to and from the probe assembly. Light entering the assembly is directed into the fluid, the light being absorbed or scattered by particles in the fluid as it passes therethrough. The amount of remaining light is sensed and a light output from the probe is produced whose intensity is a function of the amount of remaining light. A light detector measures the light output of the probe assembly and produces an indication of the absorbance or turbidity of the fluid.

Abstract: This invention relates to an optical absorptiometer which is characterized by a light source unit of a broad wavelength having a source of constant energy which is collimated into two light beams, one of which is transmitted through the liquid to be measured, and another beam which is transmitted through a conductor and acts as a reference beam, and a detector unit which contains two photocells, one photocell for measuring the beam transmitted through the liquid to be measured, and another photocell which measures the reference beam, a position in the absorptiometer for optically placing the liquid to be measured between the source unit and the detector unit, and means for measuring the energy difference between the light beams of the measured liquid and the reference beams in terms of absorbance, and means for converting this result to an electrical signal.