Example: Product optimization with flow agent
An important quantity, which is measured with the Ring Shear Tester,
is the flowability ffc. The flowability is a measure for
the effort required to initiate flow. The larger the flowability,
the better a powder flows. To find out the effect of a flow aid
additive on the flowability, mixtures of the powder with different
flow aid concentrations have been prepared and then tested with a
diagram the flowability ffc of the product is plotted vs. the
concentration of the flow agent (nano-powder). The red graph
represents the instantaneous properties, while the blue graph shows
the properties after 22 hours storage at rest (e.g., storage of the
product in a silo or a container).
It is clearly visible that the flowability is smaller after 22 hours
storage. This indicates that the product exhibits a pronounced time
consolidation effect. Time consolidation is also known as "caking".
The flowability shows a maximum at a flow aid concentration of
0.55%, i.e., this flow aid concentration results in the best
flowability. An increase of the flow aid concentration beyond 0.55%
has a negative effect on the flowability.
Further application examples
- Quality control: Ensuring a product with good dosing behavior
by limitation of the range of flowability.
- Quality control: Ensuring a product which has a sufficient
flowability even after storage at rest over a long period of
- Investigation of the influence of the particle size
distribution on the flow behavior.
- Investigation of the influence of the storage temperature on
the time consolidation effect (caking).
- Optimization of production processes regarding good
flowability of the products..
- Optimization of the powder composition for homogeneous filling
of the dies of a tablet press.
Publications on the application of Ring Shear
The use of Ring Shear Tester measurements for various
applications is described in a number of publications. Some of
these publications can be found in this list:
International Round Robin test on Ring Shear
Some years ago, an international Round Robin test took place on
our ring shear testers (small tester RST-XS; large tester
RST-01.pc), in which many of our customers in Europe and the USA