Experimental Determination of the Optimum Ball Impacts for Solution of Silo Obstruction (RESEARCH NOTE)

A number of considerations should be taken into account in design stage to avoid the foregoing malfunctions of vertical silos containing ore concentrate. One of the silo problems is obstruction at the outlet which blocks the material flow. There are procedures, depending on the material properties and silo dimensions, to solve this problem. A common way is impacting the silo wall by manual hammering or pneumatic impacting. In the present work, the hopper of a laboratory silo containing the magnetite concentrate, for obstruction solution is impacted by single ball. Impacts lead to the bulk fracture and material discharge. Capturing the new arc profile after discharge and registering the required number of impacts which provide the continuous material flow helps us to determine the optimum impacts. Results show that the wall displacement due to the impact is a governing factor in obstruction solution and the best impact position is near the outlet. It is also concluded that at a constant kinetic energy the impacts by higher mass balls are more effective than the impacts by higher velocity balls.