Calculation of the Sizes of Output Openings of Gravity Feeders for Volumetric Discrete Dosing of Powder Bulk Materials

Abstract

In the process of discrete dosing, a zone of plastic flow appears in the gravity feeder at the moment of release, and this zone extends a very small distance into the mass of the powder material forming a dynamic arch. This dynamic arch can become a static one when the size of the outlet is insufficient. After solving the equation of the energy balance with the help of the Mohr–Coulomb yield criterion the formulae were obtained to calculate the sizes of slit and round arch-forming openings.

Experiment tests have shown that the suggested calculation method is in very good agreement with the experimental results for finely dispersed cohesive bulk powder materials. Based on the analysis of experimental data, a dimensionless criterion has been suggested to evaluate the applicability of the method depending on the physical and mechanical properties of the powder material.