First published in Milling and Grain, April 2016
A fundamental consideration for handling and discharge arrangements for cereal products in the chain from field to end of process is that of controlling the generation of fugitive material (dust) into the atmosphere. The need to control dust levels is driven by a number of factors such as the long term health of operators, plant hygiene or plant operational safety (ATEX/DSEAR).
High dust levels can result from the stripping away of ‘piggy back’ fines (i.e. dust that has attached to the outside of larger particles and is transported with them through the process) by impact or counter directional air flows. Alternatively, dust can be generated through the breakage of larger particles (i.e. impact or shear plane damage).
Handling operations that deliver the former set of condition for removal and transportation of ‘piggy back’ fines would typically include the filling of bulk storage units by either gravity of pneumatically – where significant distances for free-fall conditions or trajectory establishment exist.
The direct generation of dust through particle damage can occur in large stores where the discharging flow channel expands and flows through static regions of product (often referred to as internal mass flow) or where constant capacity feeders such as augers, drag links or belts extract from long outlets without optimised design or interface considerations – in which case the feeder will tend to drag conveyed product beneath a nonactivated region of product.
Read the full article in Milling and Grain HERE.
A fundamental consideration for handling and discharge arrangements for cereal products in the chain from field to end of process is that of controlling the generation of fugitive material (dust) into the atmosphere. The need to control dust levels is driven by a number of factors such as the long term health of operators, plant hygiene or plant operational safety (ATEX/DSEAR).
High dust levels can result from the stripping away of ‘piggy back’ fines (i.e. dust that has attached to the outside of larger particles and is transported with them through the process) by impact or counter directional air flows. Alternatively, dust can be generated through the breakage of larger particles (i.e. impact or shear plane damage).
Handling operations that deliver the former set of condition for removal and transportation of ‘piggy back’ fines would typically include the filling of bulk storage units by either gravity of pneumatically – where significant distances for free-fall conditions or trajectory establishment exist.
The direct generation of dust through particle damage can occur in large stores where the discharging flow channel expands and flows through static regions of product (often referred to as internal mass flow) or where constant capacity feeders such as augers, drag links or belts extract from long outlets without optimised design or interface considerations – in which case the feeder will tend to drag conveyed product beneath a nonactivated region of product.
Read the full article in Milling and Grain HERE.
The Global Miller
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