Convex Bladed Mixed Flow (CBMF) Impeller: A High Performance Agitator for Mixing Slurries

This study investigates the effectiveness of the convex bladed mixed flow (CBMF) impeller for mixing and aerating pig slurry. The primary objective is to assess the power consumption characteristics of the CBMF impeller in both aerated and unaerated conditions on a laboratory scale, using a tank diameter of 0.29 m and an impeller diameter of 0.098 m. These characteristics are compared against experimental data from a Rushton turbine and a pitched-bladed turbine of equal dimensions. Additionally, farm-scale experiments were conducted with tank diameters of 2.5 m and an impeller diameter of 0.83 m to analyze the power consumption and solid suspension characteristics of the CBMF impeller in unaerated pig slurry. The mixing efficiency was measured using a mixing index which indicated that the CBMF impeller maintained high homogeneity levels in the slurry. Notably, to achieve a mixing index of 2.5 × 10 -2, the CBMF impeller's power consumption was significantly lower—13% of that required by the pitched-bladed turbine and only 1.5% of that for the Rushton turbine. Comparisons were made considering the similar characteristics of the slurries tested in both current and earlier experiments.