Filling of a grain silo. Part 2: A new filling method for uniform distribution of fines in a small scale silo

During top filling of a storage silo, granular material containing a range of particle sizes, the smaller particles (fine material) accumulate under the filling point. This interferes with air distribution preventing effective aeration of regions with higher percentages of fine material. In the first part of the study, the distribution of broken corn and foreign material (BCFM) was investigated in a small scale silo filled from a central filling point (CFP). In this second part, a new variable filling point (VFP) method was developed and tested as a means of reducing the non-uniform distribution of fine material during filling. The VFP mechanism produces rotational and diametric motion of the fill pipe using a rotating rim placed at the top of the experimental silo. Factors that were varied included initial BCFM (BCI), volume flow rate of material (Q), fill pipe diameter (DF) and ratio of rotational velocity of the rim to the linear velocity of the fill pipe (VR/VL). The findings of the VFP experiments demonstrated that the distribution of fine material became more uniform with increasing VR/VL, BCI, Q, and with decreasing DF. The comparison between CFP and VFP experiments showed that the proposed VFP filling method gave a more uniform distribution of fine material, eliminating zones with high concentrations of fines.