| The optical fiber measurement of light has been investigated for sensor applications in the milk processing industry. Specifically, for sensors capable of predicting the appropriate time to cut cottage cheese curd and for determining the milkfat level in milks and creams with fat levels ranging from 0.05 to 40 weight percent (wt%). This work is a necessary step toward the development of practical sensors for use in the milk processing industry, or any other process involving particulate solutions.; An empirical cutting time prediction algorithm based on the measurement of light backscatter was developed and tested in a commercial cottage cheese processing plant. Empirical models were developed for light transmission in skim milk (0.05 to 0.21 wt%) and for light backscattering in cream (10 to 40 wt% milkfat). In each case, three modeling schemes were tested to determine the best scheme for sensor design. In order to test the prediction algorithms for determining milkfat level the amount of light either transmitted or backscattered was measured using a fiber optic system. An optical fiber directed light into the sample of interest and a second fiber received the fiber receives the transmitted or backscattered light, depending on the orientation of the two fibers.; For the empirical models, three modeling schemes were tested to determine the best scheme for sensor design. There were no significant differences in the predictive power of the three models considered in each study. Hence, the modeling scheme that is simplest for sensor design and fabrication was the scheme of choice. The light transmission at a single distance and the ratio of light backscattering at two distances were chosen as the best scheme for sensor design.; The theoretical model appears to work well with the lower fat milks (0.05, 0.5, and 1 wt% milkfat). Results suggested that, with proper use of a radiative transfer model, it should be possible to determine physical properties of particulate fluids from the measured light scattering profile. |
