Application

In the 1960's, when shear testers for powders and bulk solids, especially the Jenike Shear Tester, were introduced, they were intended to be used first of all for silo design.

For silo design mechanical properties of the bulk solid have to be known which characterize the flow behavior sufficiently accurate. Only on the basis of safe and reliable data it one can predicted, for example, the minimum size of a hopper outlet required to avoid arching.

Due to easier operation, automatic test procedures and good reproducibility, our Ring Shear Testers have broadened the range of application of shear testers. Thus, many of our Ring Shear Testers are used in the context of flowability measurements and product optimization.

Example: Product optimization with flow agent

An important quantity, which is measured with the Ring Shear Tester, is the flowability, ff_c. 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 shear tester.

Flowability vs. flow agent concentration

Flowability vs. flow agent concentration

In the diagram the flowability, ff_c, 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 time.
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 Testers

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:

List of publications (pdf)

Areas of application, Distribution partners

Examples of industries in which our ring shear testers are used, for bulk materials that are tested with our ring shear testers, and countries in which our ring shear testers are used, and our distribution partners can be found here:

Areas of application, distribution

International Round Robin test on Ring Shear Testers

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 participated.

Round Robin