The FT4 Powder Rheometer was developed to measure the flowability and processability aspects of powders. Its approach differs from all existing techniques as it sets out to establish a reproducible dynamic flow condition that more closely resembles the way that powders move during handling and processing.
These reproducible flow conditions are used to evaluate how different powder samples compare in relation to factors such as moisture content, level of aeration, particle size range, or merely different batches of the same material on volumes down to 10ml
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.
Physical characteristics of the particles, like size, shape, angularity, size variability and hardness will all affect flow properties. External factors such as humidity, conveying environment, vibration and perhaps most importantly, aeration, will compound the problem.
The rheometer is a fully automated, small volume shear cell module that enables users to extend the range of shear testing applications. Materials such as early stage formulations, which is often in limited supplies, is a typical example.
The FT4 is used to conduct an array of powder flowability tests. These provide a means to characterise the flow properties of powder materials and relate them to performance in process.
Where shear testing is required to complement flowability data, both the new small volume shear cell and the existing standard shear cell accessory offer significant advantages over conventional methods.
Shear testing using the FT4 minimises operator involvement for greater repeatability and reproducibility of results. And it is fast, with tests completed in around 40 minutes.
Measurements can be made at low levels of material compaction, thanks to the system's high sensitivity, over a wide range of stresses up to 23 kPa, allowing simulation of many different packing conditions.
Conditioning of material before testing ensures homogeneity and a high degree of repeatability.
Additional benefits include a powder-conditioning feature that allows tests to be repeated and compared, an ability to measure the shear strength or cohesion of powders and the capability to measure the rheology of powders and complex semi-solids.
Freeman Technology will introduce its new small volume shear cell for FT4 at Powtech 2005, which is taking place Nürnberg, Germany between the 11th. - 13th October.