Measuring powder flowability: A comparison of test methods — Part I
Measuring your dry bulk powder's flow properties, which helps determine the powder's flowability, is the first step in designing a silo or other bulk handling equipment that won't develop arching, segregation, or other flow problems. This two-part article compares several methods for measuring flowability. Part I provides the background you need for evaluating various flowability test methods against the shear test developed by A. W. Jenike, which is the industry standard but requires equipment that is hard to manipulate. Part II, which will appear in the June 1996 issue, can help you choose a test method that is simpler to perform than the Jenike shear test but still provides the qualitative or quantitative flowability measurements you require.
You need a lot of information, including comparative measurements, to evaluate your powder's flowability. This information can help you determine, for instance, how to design handling or storage equipment for your powder or whether handling the powder will require a flow aid or flow agent. While the Jenike shear test has become the standard method for measuring powder flowability, the degree of training and experience a user must have to manipulate the equipment is causing many users to switch to other methods, which are often based on different measuring principles and physical values.