Measurement of flow properties of powders at low consolidation loads (1–6 kPa) using the computer controlled shear cell (CCSC)

Many handling problems in industries dealing with particulate materials can be avoided by designing the handling systems and storage structures based on the flow properties of the materials stored or processed through them. Flow property data at low pressures are essential for design in several cases. The objectives of this study were: 1) to measure the flow properties of five test materials at low consolidation loads (1-6 kPa) using the computer controlled shear cell (CCSC) as a computer controlled Jenike tester (CCJT) and as a dynamic yield locus tester (DYLT), and 2) to evaluate further the DYLT which works on the constant volume concept. The five powders tested were: 1) BCR limestone, 2) glass fibers, 3) ground silica, 4) microcrystalline cellulose, and 5) wheat flour. Results showed that the flow properties, cohesion and angle of internal friction, measured using the CCJT and DYLT were statistically similar (p>0.05) for BCR limestone, ground silica and glass fibers at all consolidation stresses. The angle of internal friction at consolidation stress of 5,2 kPa was the only flow property significantly different (p<0.05) for microcrystalline cellulose. The values of cohesion and angle of internal friction were significantly different (p<0.05) for wheat flour between the CCJT and DYLT at consolidation stresses of 3.2 kPa and 5.2 kPa. The flow parameters for all five powders were statistically similar (p>0.05) when compared between the CCJT and DYLT at consolidation stress of 1.2 kPa, which shows that the CCSC is a promising tool for measurement of flow properties at low pressures.