Powder rheology can be used to comprehensively analyse powders and bulk solids. This ensures efficient quality control and smooth processing. But the versatility of powder rheology is also becoming increasingly important in research and development and can help, for example, with scale-up.
The rheometers of the MCR Evolution series from Anton Paar are characterised by their precision and, due to their modular design, by their extremely flexible application possibilities. The shear cell and fluidisation cell open up versatile and unique possibilities for analysing powder behaviour.
The flow behaviour of powder is measurable
The production, processing and storage, but also the incoming and outgoing control of granular media pose challenges. These are mainly due to the complex flow behaviour of powders, which is influenced by a variety of factors: Particle size and shape, chemical structure, moisture, temperature, packing behaviour, static charge or surface morphology.
Various templates in the "RheoCompass™" rheometer software allow easy test execution with automatic subsequent analysis.
The powder fluidisation cell
This measuring cell can be used to characterise the behaviour of powder in a fluidised or de-aerated state. For example, pneumatic transport is simulated or segregation/desegregation is analysed qualitatively.
The unique, patented dust protection system allows clean and easy handling of samples and protects the user and the instrument from fine and potentially hazardous dust.
A typical measurement method is to determine the "pressure drop" to detect the volume flow for incipient and complete fluidisation. This is relevant for powders that are pneumatically conveyed or filled.
The determination of the air holding capacity, the cohesive strength, the compacting behaviour or the flow curve for the measurement of the shear rate- and volume flow-dependent apparent viscosity in the non-fluidised, subfluidised and fully fluidised state can also be easily realised.
The powder shear cell
This cell is used to characterise powders that are in a consolidated/compacted state - as in a silo or during mechanical conveying. For this purpose, the powders are consolidated and sheared. In this way, a variety of properties such as flowability, internal friction angle or compressive strength can be determined.
In addition, the powder shear cell is compatible with temperature and humidity options and allows precise control of the environmental conditions during measurements. In this way, it is easy to investigate the influence of temperature and humidity, for example in the case of hygroscopic powders, on the manufacturing process or during storage.
A typical measurement method is the shear test to understand how the powder behaves under different stress conditions. This can be used to determine the emptying behaviour of both a full and an almost empty silo.
The MCR rheometers
Take advantage of Anton Paar rheometers which are used for routine quality measurements, but also for high-end R&D applications, in rotation as well as oscillation for applications of any kind. Dynamic mechanical analyses in torsion, bending, compression and tension are also possible.
The MCR rheometers are based on cutting-edge technology: The built-in motor is based on technological highlights such as the air-bearing EC synchronous motor, the normal force sensor integrated in the air bearing, the TruRate™ sample-adaptive motor control for rotation tests and the TruStrain™ real-time position control for oscillation tests.