The Effect of Charging Methods of Powders on the Incipieint Bulk Density of Powder Bed in a Container

The effect of charging methods on the incipient state of packing of various kinds of powders was investigated experimentally. Glass beads, crushed glasses and limestones with various kinds of size respectively were selected as powder samples, and screening with differnt opening mesh sizes, funnel and spatula pouring, the latest as the funnel with infinite opening, were used as charging methods. The results obtained are as follows.The incipient bulk density (1-e0) of the same size particle changes remarkably with the change of the ratio of the opening size (or screen mesh size) D0 to the particle size Dp, when the ratio is small. And this tendency in appeared to be reversed according to the particle size and there can be found a kind of equilibrium size, of which the bulk density (1-e0) is constant irrespective of the ratio of D0/Dp. This specific size of particle becomes large as the irregularity of particle shape increases. Further when the size in large, the effect of D0/Dp on the bulk density becomes large as the shape of particle deviates from sphererical.