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The new Aeration Control Unit for Freeman Technology’s FT4 Powder Rheometer allows fine control of air flow through a powder under test and enables the automated measurement of the powder’s flow properties as a function of increasing levels of aeration. At maximum aeration - or for some powders, fluidisation - the energy required to make a powder flow is reduced by a measurable factor, known as the Aeration Ratio (AR). This varies from around 5 for cohesive powders to in excess of 1000 for fluidisable powders. It is therefore an important flow performance indicator.

The bulk properties of powders can be greatly affected by even small amounts of entrained air. The aeration control unit allows evaluation at very low air velocities down to 2mm/min. Aeration at higher velocities up to 2000 mm/min can examine the fluidisation behaviour that has important practical processing implications in many industries. These include toner production, powder coatings and pharmaceutical manufacturing.

The FT4 with the new aeration control unit can be used to determine the flow properties specification needed to optimise production and achieve the required product quality. In addition, the system can be used on a day-to-day basis to verify that powder flow properties meet the necessary specifications, for predictable and consistent processing performance.

Powders always contain air and the amount significantly alters the flowability of the powder bulk. Consolidation removes air and increases the friction between powder particles causing high resistance to flow. Aeration reduces flow resistance and can result in fluid-like behaviour. The rate of release of entrained air from a powder bulk is another important characteristic that can be determined using the FT4 with aeration control unit.

Full automation of the AR measurement on the FT4 Powder Rheometer enables its accurate and reproducible determination. The elimination of user variability allows confident discrimination of even small differences between powders, with data reproducibility typically better than 1%. Furthermore, unattended operation frees analyst time for other tasks.

In addition to its use in the laboratory, the FT4 Powder Rheometer with Aeration Control Unit can easily be set up close to a production line for routine QC measurements.

The Aeration Control Unit is one of a series of automated accessories for the FT4 Powder Rheometer, designed to fully automate powder testing procedures.