The Placement of Inserts to Break Arching in Hoppers

Abstract

A conical insert to avoid stable arch formation is placed in a conical hopper for storing a cohesive powder. The insert in the hopper forms an annular ring-shaped converging channel, in which stresses exerted by powders are analysed. Methods are given for determination of the annular ring-shaped opening and the hopper outlet, and an equation of estimating the vertical force on inserts is also described, comparing favourably with observations. The placement of inserts leads to a decrease of the minimum outlet diameter of hoppers through which powders flow under gravity.