In-line ultrasound Doppler based rheometry for processing applications
Special Symposium - Innovations in Food Technology (LMC Congress)
Modern Analysis: Chemical & Multivariate Analysis (Food-6a)
Keywords: In-line rheology, process applications, suspensions, liquid displacement
The competitiveness within industry is increasing and has driven a conscious move from traditional quality assurance laboratories within the factory towards real-time control of quality parameters and process control. The control of temperature and mass flow is well developed whereas there is insignificant control of rheological properties, especially within the process line. A new rheological method that involves simultaneous measurement of radial velocity profiles (UVP) in combination with a pressure difference (PD) technique has been used to determine rheological properties directly in the process line. Instantaneous velocity profiles were determined using a pulse Doppler ultrasound velocity profiling technique. Rheological parameters were then derived from non-linear regression analysis using rheological models. Complex non-Newtonian model- and industrial suspensions were investigated over a wide range of volumetric flow rates and concentrations. It was shown that it is !
possible to determine the rheological behaviour of a variety of complex non-Newtonian and highly concentrated systems such as aqueous cellulose fibre suspensions, vegetable sauce and drilling mud. These would not have been possible to study using conventional viscometers due to the suspended large particles which were much larger than the available measuring geometries. The UVP-PD method also has significant advantages over conventional techniques in being non-invasive and applicable to highly concentrated opaque fluids. Results from in-line rheological characterization of various suspensions will be presented as well as results from liquid displacement experiments mimicking industrial product changes and washing cycles.
Presented Thursday 20, 11:45 to 12:00, in session Modern Analysis: Chemical & Multivariate Analysis (Food-6a) Continued.
