Design and application of a novel power-free tubular dynamic mixer

To address poor hydraulic shock load resistance, excessive energy consumption, and low mixing efficiency in existing mixers, a novel power-free tubular dynamic mixer was designed. In this design, orifice size adjusts dynamically based on water flow rate by spring expansion and contraction. Springs connect to the orifice plate and maintain a nearly constant flow velocity. A one-year comparative experiment was conducted at two water treatment plants to compare the novel dynamic mixer with mechanical agitation and tubular static mixers. The results showed that the dynamic mixer achieved an annual average sedimentation outlet turbidity of 0.70 NTU, a coagulant dosage of 68.94 mg/L, a chemical oxygen demand (COD Mn ) of 2.18 mg/L, and a residual aluminum content of 0.078 mg/L; these values were lower than those of the static (1.71 NTU, 85.16 mg/L, 2.73 mg/L, and 0.133 mg/L, respectively) and mechanical agitation (1.32 NTU, 80.03 mg/L, 2.39 mg/L, and 0.091 mg/L, respectively) mixers. This power-free mixer combines the effective mixing of mechanical agitation mixers with the energy efficiency of tubular static mixers, thereby yielding the lowest operating cost. Overall, this novel mixer exhibits strong potential for widespread application in water treatment, seawater desalination, and advanced pretreatment. • Designed a novel power-free tubular dynamic mixer. • Adjust the size of orifices according to changes in water inflow rate, Strong shock load resistance. • Stable output water quality, lower effluent turbidity and residual aluminum content. • It can save coagulant dosage by 10-30%. • Solved the back-mixing problem present in other types of mixers.