Self-discharging flat-bottom centrifugal basket design

Abstract

Abstract

The final stage of sugar production is the separation and drying of grown sugar crystals from the viscous slurry called massecuite. Massecuite is poured into a spinning basket and washed. The centrifugal force purges the wash from the meshed basket wall. Sugar crystals left behind in the basket are spin dried. Dried sugar crystals are either scraped or self discharged from the basket. A basket with an external scraper, a flat-bottom basket, has a typical process cycle of 180 s inclusive of 40 s scraping time. A self-discharging (taper-end) basket has a typical process cycle of 150s inclusive of 8 s discharge time. However, the material-handling capacity of the self-discharging basket is poorer, and the processed sugar quality is inferior as it has traces of molasses and therefore has a yellow tinge. Acceleration of the centrifugal basket requires a very large amount of energy because of its innately high moment of inertia. A ‘self-discharging flat-bottom centrifugal basket’ design is proposed. This basket would have material-handling capacity similar to that of a flat-bottom basket and it would deliver sugar of similar quality. It has no external scraper and sugar discharge time would be 8–10 s. It has a lower moment of inertia and would save more than 15 per cent energy on the inertial basket load.