Low Shear Mixing with a Novel Impeller Design

Hydrofoil impellers are considered to be low shear devices. Recent research indicates that hydrofoils may produce very high local energy dissipation that may lead to cell, cell damage, or product degradation. This paper presents a novel approach to low shear mixing for shear sensitive mixing applications. Lab studies were performed on shear sensitive solids with the hydrofoil impeller and with the new low shear impeller at uniform solids suspension in both cases. The long term mixing indicated no particle attrition while using the Low Shear Impeller and significant damage to solids mixed with the hydrofoil impeller. Particle Image Velocimeter was used to measure local energy dissipation for different standard types of impellers and the results were compared with Low Shear Impeller.