Categorisation of Powders According to Behaviour in Handling

The following is a short account of powder classification in these three handling applications. 

The classification of powders according to their handling characteristics must, therefore, be done on the basis of direct test results. 

A precise definition of the flowability of a powder is only possible with several numbers and curves, derived from a family of yield loci of the powder (measured with a shear cell) - see section 4 for further detail. Jenike23 proposed a simpler classification, according to the position of one point of the failure function (at a fixed value of the unconfined yield strength, say 5 lbf (22.3 N) with the Jenike shear cell, i.e. 3112 Pa or 65 lbf/ft2) with respect to the flow factor line (straight line through the origin, at a slope l///where//is the flow factor) - see Fig. 8 for a schematic representation of this. 

If the point on the failure function at 5 lbf (22.3 N) lies on flow factor line of  

4 // 10 then the powder is easy-flowing and 10 ff then the powder is free-flowing. 

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