Introduction
The handling of materials in bulk form is a major activity of a vast number and variety of industries throughout the world. In particular, the various mining and associated process industries rely heavily on bulk handling operations So too do the agricultural, food processing, pharmaceutical and manufacturing industries. The costs of handling operations are very substantial indeed and for this reason it is of the utmost importance that all bulk handling and storage facilities be designed and operated with a view to obtaining both maximum reliability and efficiency coupled with maximum economy. In view of the magnitude of the costs involved in handling bulk materials, even small incremental gains in efficiency can lead to substantial cost savings.
In the past the design and operation of handling systems for bulk solids has, all too often, been treated very empirically. This applies particularly to storage bins, silos and surface storage facilities such as stockpiles and gravity fed reclaim systems. There have been many instances of costly flow interruptions such as those caused by the bulk solid forming stable cohesive arches over the openings in the bottoms of storage bins or holding-up against the bin walls without discharge taking place. In most cases such flow interruptions are directly attributable to incorrect design with little or no regard to the flow properties of the material being handled. On other occasions catastrophic structure failures of bins and silos have occurred due to a lack of appreciation, at the design stage, of the magnitudes of the dynamic wall pressures that occur during discharge...
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