Tech Brief: Run Your Rotor/Stator Mixer At Maximum Speed To Optimize Particle Size Reduction

High shear mixers feature a four-blade rotor running at tip speeds in the range of 3,000-4,000 feet/min within a close tolerance fixed stator. This type of mixing device creates mechanical and hydraulic shear by continuously drawing product components into the rotor and expelling them radially through the openings in the stator.

Running the rotor at a particular tip speed yields a corresponding equilibrium, which can be represented through the size distribution of a dispersion or emulsion. Operating below this tip speed, even over a long duration, could produce a different distribution profile. The maximum speed setting of a high shear mixer therefore provides the optimal mixing results in terms of particle or droplet size reduction (with the exception of shear-sensitive applications). Many are reluctant to run their mixer at maximum speed for fear of overworking the machine. As long as the power draw is within the machine’s range, running at the maximum speed is desirable, as you benefit from the highest tip speed that the mixer can deliver. Well-designed mixers work just as well running continuously at maximum speed as at lower speeds.