The importance of uniform drawdown by feeders
Whenever a bulk material is stored the contents are required to flow reliably and under control during both the filling and emptying processes. Few problems become apparent during filling, although some may be caused that show later. The regime of flow generated during the discharge process depends on the storage vessel construction and properties of the bulk material being handling, but essentially follows a mass or funnel flow form, depending whether the total stored contents move during discharge.
The two major benefits of Mass Flow are the securement of reliable flow without arching or ‘ratholing’ and the elimination of indeterminate residence time due to static regions of storage during discharge. Other benefits are secured are that the risk of ’flushing’ is reduced and that segregation that may have occurred during filling is redressed. It is essential for mass flow that extractions takes place over the entire area of the hopper outlet. However, to secure