New aeration control unit for FT4

Ideal for pharmaceutical manufacturing as well as toner production and powder coatings, the unit, when coupled with the FT4, can be used to determine the flow properties needed to optimise production and achieve the required quality.

The elimination of user variability through automation allows discrimination of even small differences between powders, with data reproducibility typically better than 1 per cent.

In addition to its use in the laboratory, the FT4/unit set-up can be set up close to a production line for routine QC measurements.

The FT4 Powder Rheometer's approach differs from all existing techniques as it sets out to establish a reproducible dynamic flow condition that closely resembles the way that powders move during handling and processing.

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 system takes this into account having been designed for use on a day-to-day basis to verify that powder flow properties meet the specifications, for predictable and consistent processing.

Powders are probably the least predictable of all materials in relation to flowability because of the large number of factors that can change their rheological properties.

The main problem is 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 FT4 with aeration control unit allows the rate of release of entrained air to be measured from a powder bulk allowing 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 processing implications in the pharmaceutical industry.

Inclusion of the aeration control unit is another addition to the company's series of new 'plug and play' accessories designed to bring automation to FT4 powder testing processes.

The move has been made possible by the recent development at Freeman​ of a universal control card for the system that provides an interface between the instrument, the accessory and the user.