A Mixer Viscometry Approach for Blending Devices

The Matching Stress Method is a mixer viscometry technique used to estimate mixer constants and viscosity using systems of complex geometry. Three Newtonian standards and three hydroxy‐propyl‐methyl‐cellulose (HPMC) solutions were used as model systems. to determine the mixer constants, a counter‐rotating, twin‐rotor blender was modified with a torque transducer and speed sensor installed between a drive shaft and a 0.75 hp (559.3 W) electrical motor. Mixer constants were determined using a concentric cylinder approximation of shear stress in an effort to match this approximation with shear stress measurements determined from a bench top rheometer. Mixer constants for the model systems ranged between 2.01 and 2.87 rad−1 with an average value of 2.57 rad−1 for all fluids. the results demonstrate a successful technique for providing accurate viscometric data during mixing processes. Such efforts could be followed to implement real time, quality control strategies and power estimation in scale‐up procedures.