Aeration Control Module for FT4 Powder Rheometer by Freeman Technology

Freeman Technology's Aeration Control Module allows the measurement of the flowability of aerated powders. The bulk properties of all powders are affected by the presence of entrained air, as it fills the spaces between the particles, or in the case of cohesive powders, is incorporated into agglomerates of fine particles. The amount of air present determines how the solids interact with each other and this has a direct impact on the flow properties.

The addition of air occurs naturally when powder is moved freely - for example, when discharging from a hopper. In other situations, air is added as part of the process, such as when powder coatings are transported in a coating system. When aerated, the contact between particles is reduced and less energy is required to move the powder. This reduction is described by the Aeration Ratio (AR), which can be measured automatically using the Aeration Control Module on the FT4 Powder Rheometer.

The Aeration Control Module - what it can do

The Aeration Control Module is controlled directly by the FT4 Powder Rheometer control system allowing the following types of automated test programs to be run:

Aeration or fluidisation assessments to determine response to increasing levels of aeration - up to fluidisation velocities if appropriate for the powder - see Fig 3 below.

De-aeration testing to determine how readily a given powder releases entrained air following aeration

Permeability measurements derived from measurements of pressure drop across a powder bed during aeration tests - see Fig 2 above.

Advantages of automating the measurement

The Aeration Control Module is fully controlled by the FT4 control system and requires no operator involvement once the test has commenced

Provides an accurate and reproducible measurement of aeration and de-aeration characteristics – typically to an accuracy of +/- 1%

Operator errors are eliminated – a particularly important factor when dealing with small differences in powder properties

The test sequence is fully programmable, ensuring that each stage is carried out at the precise testing rates and times specified, to maximise reproducibility of results

An automated test can be set up to run as a QC measure close to the plant