Angle of Repose, Fall & Spatula Testing with the Micron Powder Characteristics Tester PT-X


The Micron Powder Characteristics Tester PT-X employs the methods developed by Ralph L. Carr (Carr Indices) to determine the “Flowability and Floodability” of dry powders.  The Model PT-X is the latest design which utilizes state-of-the-art features to identify the specific characteristics of powdered samples for a wide range of application fields.

The Model PT-X determines a range of dry powder characteristics including angle of repose, cohesion, aerated density, uniformity, dispersibility, and compressibility. Other characteristics include angle of fall, packed density, angle of spatula, angle of difference, and particle size

Among the Model PT-X’s key features are an automated vibration with electronically controlled vib-sensor for repeatable results, optional integrated HEPA filter dust protection, and test sieve identification (measure by recording test sieve serial number). The unit also offers complete powder characterization in one instrument, reduced operator intervention insuring analysis accuracy and repeatability, and user friendly software which reduces analysis time.

The unit complies with FDA Tapped Bulk Density (USP) ASTM, Kawakita’s equation for compressibility, and has a specially designed feeder for reliable sample feeding. Since 1968, when the original Powder Tester was developed, more than 3,500 units have been delivered to companies worldwide. 

This video offers a quick tutorial on how to perform the angle of repose, fall, and spatula tests using the Micron Powder Characteristics Tester PT-X. For the angle of repose, the technician follows the software and sets up the machine and componentry and then loads about three-quarters of the powder material. Vibration of between 0.5-3 mm is set up along with vibration time of 170 sec. and 10 sec. slow down. The vibration begins and the heap builds and fills the platform. A photo is taken to determine the angle of repose which in this instance is 35.4 deg. (20 Carr index)

The angle of fall is determined when G forces tap the heap and changes its shape. An angle measurement of 19.8 deg. (22.5 Carr index) is taken along with an angle of difference of 15.6 deg. (16 Carr index).

Finally, the angle of spatula is a measure of the angle of internal friction. Again, componentry and spatula are set up, material is added, and vibration is set. The spatula lifts and carries the material and a camera takes a first measurement of 40.9 deg. angle. A second measurement is 23.9 deg. The angle of spatula is an average of 32 Carr index.

Click here to learn more about the PT-X