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Why Measure Powder Flow?


The classic problem when working with powders is their failure to discharge reliably from bins, hoppers, silos, feeders, dosing machines, packing machines, etc. Their unpredictable nature causes interruptions in the production process and at times requires complete plant shutdown in order to correct flow restrictions and stoppages. Failure to flow reliably also leads to variations in pack weight, mixture, performance and sensory properties of powder products.

Quality Control Departments handle raw materials from multiple suppliers in powder form. The variability in particle size and distribution, moisture content, and basic ingredients requires a battery of incoming inspection tests, none of which assure that proper flow will take place when the powder is loaded into the plant equipment.

R&D Departments adjust formulations of powder products to satisfy customer demand for improved properties, such as better coating action for paints, enhanced taste for spices, rapid dissolving of chemicals, etc. The unpredictable flow of new formulations causes production problems when the process is scaled up to high volume.


The PFT Powder Flow Tester eliminates flow problems with a Flow Function test; a proven scientific method used to analyze powder flow behavior. ASTM D6128 describes the Flow Function test procedure, which consists of compressing and shearing powder samples in a defined annular shear cell, using an established well-defined methodology. The Flow Function test enables you to:

  • Calculate the critical outlet dimensions for feeders, hoppers, etc., through which powders flow.
  • Compare powders against one another for flowability, ranking, and benchmarking purposes.
  • Determine whether a powder will flow successfully through an existing plant or process.
  • Determine the required geometry for potential new solids handling equipment before purchasing.

In addition to measuring the flow function, the PFT Powder Flow Tester also measures the angle of internal friction, angle of wall friction, cohesive strength, and bulk density all of which help to eliminate potential flow problems.

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