The influence of the granulometric condition on the flow characteristics of shredded grain products in their dependence on the duration of storage
2013
Fürll, C. | Hoffmann, T.
Often shredded grain is stored up to feeding as bulk material in tower silos over a longer period. Due to time-dependent consolidation the material becomes more or less incapable of flow out. In this research, the flow characteristic of pig-feed is determined in dependence on the granulometric conditions and the storage period. For the investigations three samples of mixed pig-feed were produced with a transformed median x₅₀;₃ ⁎ of 0.335mm, 1.0mm and 5.2mm and a constant standard deviation of 0.9. The percentage of cohesive fine material with particle size x<0.2mm was 100%, 30% and 8.9% in order to represent the flow properties “very cohesive”, “cohesive” and “free flowing”. The material samples were pre-sheared by use of a translation-shear-device and afterwards stored for 20, 40 ore 90h under the consolidation stress. After that followed the shearing of under reduced normal-stress. The flow function values ffc were calculated based on the measurements. Results show that the flow characteristic is mainly influenced by the fine material portion H₃(0.2mm). Extremely cohesive behavior is present at H₃(0.2mm)=100%. At H₃(0.2mm)=30% or 8.9%, the bulk material behaves cohesively or cohesionless. Shredded grain for animal feed should have a small standard deviation and a portion of cohesive material H₃(0.2mm)<5%.
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