Use of a Neltec purge sensor to improve the efficiency of batch centrifugal operation

A purge sensor (Neltec, Denmark) was fitted to the outside of the casing of a batch centrifugal to measure the impact of the molasses/wash water on the casing. This signal correlates with the flow of molasses/wash water leaving the basket. A comprehensive series of investigations was undertaken with B massecuites to understand the response of the sensor to a wide range of settings of the centrifugal parameters. The test program demonstrated that the signal from the purge sensor is highly reproducible for the same test conditions and the response aligns very well with observations in the centrifugal, e.g. the intensity of the purge signal rises rapidly at the same time as the colour of the face of the crystal bed lightens. Analysis of the logged data has shown that the signal can be used by fugal operators to select the optimum time to commence the wash water application. The purging qualities of the massecuite can also be determined from the purge signal. A shorter series of investigations was undertaken with A massecuites on a different centrifugal and those tests confirmed the observations with B massecuites. As expected, for A massecuites the purge of molasses occurs at a lower basket speed than for B massecuites and the response of the purge signal has different characteristics.