Zwick Roell is introducing an enhanced backward extrusion apparatus with optimised testing software for measuring the dynamic viscosity of substances
This test apparatus is an economical alternative to using rotation viscosimeters.
The process does especially well in tests directly in the container.
Being able to test chunky fruit preparations or yogurt with fruit pieces is also a significant advantage.
A multitude of measurement, evaluation and display possibilities are available thanks to the testXpert testing software.
The principle of the backward extrusion fixture apparatus is based on the displacement of the test material through an annular gap between piston and test cell.
The cell is filled with the test substance and the piston is lowered into the container, pressing the material up through the annular gap.
When the piston is raised, the material flows back through the annular gap into the cell.
The Zwick Roell system can repeat this cycle as often as desired with freely adjustable shear rates.
The test can be optimally adapted to the test material, and the viscosity can be measured across the entire shear range with a single test.
The dimensions of the piston are selected depending on the test substance.
The method allows testing directly in the container during production, for example, in a bucket or cup.
The material is not pre-stressed by decanting prior to the test.
If continuous pre-stressing of the material is desired, the software can be programmed to automatically apply pre-stress under continually constant conditions.
In addition, the flow effects which take place in production systems can be reproduced by varying the annular gap and piston speed.
The integration of the intelligent and reliable software testXpert II allows convenient data acquisition and evaluation and provides professional graphical displays and documentation.
It should be mentioned in particular that each cycle can be run with a different shear rate; it is very easy to modify the testing parameters, and the test equipment settings can be stored for each type of test configuration.
This allows a simple exchange of the test setup in the texture testing machine without having to re-measure the test cell.
The training and operating costs are reduced because the user can quickly and intuitively understand the testing software on account of the meaningful symbols and concise structure.
The software remains clear despite the versatile functions and possibilities.
