CCUSE "Laboratory of biosafety, quality of food products and food safety"

Center for collective use of scientific equipment

Spare parts and additional modules for the rheometer Kinexus Pro+

req.m68cst

received

39.02 thousands of euros

Equipping the Kinexus Pro+ rotary rheometer with additional parallel plates-geometries will allow to expand the measurement range of a wide range of materials, for Newtonian and non-Newtonian fluids with low viscosity to more viscous dispersed systems: gel-like materials, soft and hard substances, polymers and others systems The wide range of plate sizes is due to the measurement of materials with different rheological parameters.

Smaller diameter geometries are used for samples with high viscosity, and larger ones (Ø50 mm) for materials with low viscosity (0.1 Pa*s). In addition, geometries with a toothed surface are used to study emulsions and suspensions, which are prone to slipping. This manifests as an early drop in viscosity during shear rate measurement, resulting in a sudden drop in viscosity and suspected slippage. This surface interface provides additional adhesion of the material to the geometry, and stimulates the smooth flow of the material. Using geometries of different diameters will allow for a more smooth variation of the gaps between the geometries in the measurement and follow general rules of thumb, and will provide sufficient interaction to eliminate wall effects that cause artifacts in the results. The possibility of combining the geometries of the cone and the plate will allow to measure the geometries at the set gap (automatically controlled by the software). This allows absolute viscosity to be measured when the entire sample is subjected to the same shear rate, a significant advantage over parallel plate geometries that have a range of shear rates along their radii and only the average value is reported. For the study of materials and systems sensitive to temperature effects, or in which phase changes/transitions occur under the influence of temperature, elimination of temperature gradients, and when measuring temperatures significantly higher or lower than the ambient temperature, a cartridge is needed for setting temperatures when measuring from -5C up to 180°C, or from -40°C with an active heat exchanger. The cartridge is a combination of a Peltier element with additional heaters for active control of radial and vertical heat losses from the local environment of the sample with a resolution of 0.01°C, with measurement stability of +/- 0.1°C.