Design Parameters of Continuous Centrifugals

Abstract

Continuous sugar centrifugal is used to separate sugar and molasses from massecuite. The centrifugal basket is pierced with numerous holes to allow the molasses to escape and is lined with metal gauze, which serves to retain the sugar while allowing the molasses to pass through. The centrifugal basket is conical in shape (Fig. 1), runs at a constant speed in the range 1200 to 2200 rpm., and is fed by a continuous stream of material. The semicone angle α varies from 25 deg to 35 deg. What prompted this investigation is a fairly high level of working stress experienced in commerically available centrifugals, often close to yield stress. This technical brief presents the steady state stress distribution patterns in these centrifugals using a fairly accurate model. Since the problem under consideration is cyclic, a symmetric model using the finite element method with triangular shell elements is employed to determine the stresses and displacements. Besides, the critical speeds of the baskets have also been computed using Rayleigh’s method.