Texture Analysis in Action 2: Powder Vertical Shear Rig

Anyone who has handled powders has almost certainly come across a clogged hopper, and will know that this is caused by caking, arching or rat-holing. 

To measure the tendency of a powder to show these properties, the main property to consider is the powder’s bulk resistance to the initiation of flow. 

This helps to imitate the consolidation that occurs under the powder’s own weight when the outlet is shut and the feeder is switched off. It is when the outlet is opened and the feeder started again that the blockages can build up.

The likelihood of a blockage forming depends on both the properties of the powder and the conditions surrounding it (humidity, temperature, stress state, hopper geometry). A vertical shear test provides a method to test the commencement of flow of a powder from a packed state, imitating a filled hopper. This test can also help to determine the correct hopper outlet size for reliable flow.

Powder Vertical Shear Rig

The Powder Vertical Shear Rig is now available as yet another application that can be performed on powder samples using the Texture Analyser. During the test, a known mass of powder is transferred to the main body of the rig and compressed to a known force to create a uniform cake of powder. A trapdoor below the powder cake is released, exposing a circular surface of the cake. 

A probe slightly smaller than the hole then pushes a plug of the powder cake through the bottom of the rig. The powder is put into an almost perfect shear state (where the force is parallel with the powder movement). This Community Registered Design offers a unique means of consolidating the powder, removing the applied force and testing the resulting sample without disruption by user handling. 

Using a special sequence and macro created in Exponent software, which guides the user through the procedure, the important parameter of ‘vertical shear strength’ is automatically calculated once tests are complete.
 
Contact Stable Micro Systems today to discover the full range of Texture Analysis solutions.

---

We can design and manufacture probes or fixtures for the TA.XTplus texture analyser that are bespoke to your sample and its specific measurement.

Once your measurement is performed, our expertise in its graphical interpretation is unparalleled. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can also prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

No-one understands texture analysis like we do!

To discuss your specific test requirements click here...