Flowability Tests


Powder flowability is a very general term. It can mean many different things. In order to define it more usefully, a context is needed. For example, does powder flowability refer to powder coming from a silo? Moving through a pneumatic conveyor? Coming out of a container? All of these situations represent different behavior and have much different meanings. Therefore, different types of flowabitiy tests are suited to different situations and applications. 


Silos and large storage containers

The best flowability test to determine if powder or granular material will flow out of a silo is the unconfined yield strength test. This test measures the strength that a powder gains when it is subjected to a consolidating stress. A powder will flow from a silo or large container if the force acting on it is greater than the unconfined yield strength. The time unconfined yield strength is also very important if the powder is to be stored for any length of time.

The Multi-Flow test is also interesting to determine how evenly a powder will flow from a silo or large container once it has started moving. The multi-flow test measures a samples response as it is subjected to more and more flow energy.

The fluidization test is also important as powders and granular materials can become easily fluidized as the exit the storage container or silo. Fluidized materials are difficult to control. 


Pneumatic conveying and spraying

Pneumatic conveying and spraying are dynamic processes so dynamic tests provide the most relevant data. The tests include the Revolution flowability test, multi-flow test, and fluidization test.

High Speed Equipment

  MammmmMaMMMaterMMmmmMaterials moving through high speeding handling and packaging equipment are subjected to strong forces and air pressures. Therefore tests like the multi-flow and fluidization tests that measure materials under the influence of high flow energy are most relevant to high speed applications .

Small Containers

Low forces are used to initiate material flow in small packages and containers. Typically the material is poured from the container by the user. The flow test of the Revolution Powder Analyzer is excellent at assessing this flow behavior. 


Link to instrument-specific test pages: