The mixing of powders flowing down an inclined plane

Abstract

Abstract An apparatus has been constructed in which a pair of hoppers feed powders at controlled rates to the top end of a chute in two moving layers, one on top of the other. The layers move down the chute and at the lower end are separated again by an adjustable knife edge. Subsequent analysis of the fractions obtained enables the amount of mixing which has occurred to be determined. Since the mixing takes place under controlled conditions through a known area of contact between the powders, the apparatus measures “powder miscibility”. Two photoelectric cells enabled the powder velocity to be measured. Powder velocities and bed structure are reported for the flow of single layers of sand of various thicknesses. Mixing results are presented, in terms of an effective diffusion coefficient, for the flow of 30/36 mesh sand.