A LABORATORY EVALUATION OF OPTICAL BACKSCATTERANCE SUSPENDED-SOLIDS SENSORS EXPOSED TO SAND MUD MIXTURES

Optical suspended solids sensors were studied in the laboratory in order to obtain calibration factors and evaluate the general behavior of the instrument when exposed to suspensions of mud and sand. The sensors were found to be capable of measuring the time-averaged concentration of either suspended sand or suspended mud, but the relative sensitivity of the sensor to these two different types of sediment varied by approximately an order of magnitude. In mixtures with a constant or known mud concentration, the instrument response to the mud may be treated as an offset, and gains appropriate to sand may be used to estimate the suspended sand concentrations. Semi-quantitative observations of the effects of flow direction relative to sensor orientation indicate that significant concern is warranted. © 1990.