Presto ChemTech offers Combined Flow Impeller. Presto ChemTech offers a range of Super Impellers, Hydrofoils, Axial, Radial and many more. The Combined Flow Impeller is a dual action impeller that is used for mixing wide range of fluids in high viscosity ranges. The Combined Flow Impeller promotes up and down pumping with single impeller. It can handle high percentage of solids and it is quite energy efficient as compared to conventional impellers.