Effect of cylinder heights of a deep-depth vortex chamber type sediment extractor on sediment removal efficiency: Experiments

The muddy water flows into the vortex chamber type sediment extractor through tangential inlet pipe, and moves as a vortex flow inside the chamber. The water and sediment of the muddy water will be separated due to the gravity and centrifugal force. The flow though the bottom orifice contains higher sediment concentration, corresponding to the inflow while the flow through the overflow weir contains much lower sediment concentration. The experimental study was conducted in a deep-depth vortex chamber type sediment extractor which has a total height of 130 cm and an internal diameter of 48 cm. The horizontal deflectors of 12 cm wide are installed inside the vortex chamber. The experimental arrangement contains: one kind of inlet pipe size (D_i = 3 cm), three kinds of bottom orifice size (D_u = 0.5, 0.7, 1.0 cm), and three kinds of overflow weir height (H_o = 50, 60, 70 cm) corresponding to three kinds of the bucket depth ratio (H_o/D) (i.e., 1.04, 1.25, 1.46). The inflow discharge of muddy water varied from 80 × 10^-6 to 770 × 10^-6 m³/s. The inflow sediment concentrations are between 60.0 g/L and 65.0 g/L and the sediment used in experiments is silt sand having a median diameter of 0.041mm. According to the results of experiment, the sediment removal efficiency and overflow sediment concentration (η_s = 99.2% and C_o = 0.50 g/L) for the experiment using the bottom orifice of 0.5 cm and overflow weir height of 70 cm is better. But the bottom orifice diameter is larger, the overflow weir height is not significantly associated with the sediment removal efficiency and overflow sediment concentration.