Determination of the Strength of Consolidated Powder Materials with a Pull-Based Tester

In recent years, there has been increasing interest in the agglomeration of bulk materials. New methods are being sought to improve the measurement of bulkiness in food powders. This study aimed to design a new measuring device to assess the phenomenon of caking as well as the degree of strength of free-flowing powders. Wheat flour and potato starch have been used in the experiment and loaded into a perforated container. A steel or polypropylene measuring rod has been placed in the middle, and 5 kPa and 10 kPa were loaded, respectively. The new method is based on measuring the force through a sensor when pulling out measuring rods from the powder sample. It was shown that higher strength values have been obtained for powders loaded with 10 kPa and that groove depth has not been significant for wheat flour. Additionally, a significant difference in the evolution of the pulling force with time has been observed for wheat flour and starch, revealing a slip-stick phenomenon in the latter one. The pull-based tester is characterized by fast measurement and easy analysis of the results. The tests performed for potato starch and wheat flour have provided significantly different temporal evolutions of the pulling force.