Impellers are essential tools in meeting the mixing process requirement. Zucchetti's impellers have been developed and studied to ensure the efficiency. These impellers include screws, bar turbines, counter-flow impellers, curved blade turbines, single and double helical ribbons, and the like. Other impellers which were also subjected to research are hydrofoil high efficiency impellers, pitched blade turbines, propeller marine types, and radial blade turbines.