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Based on the calculations associated with the critical velocity theory, the best way to avoid floc roll up is to maximize the plate settler spacing. Figure 1 shows the minimum plate settler spacing that will produce acceptable results. From the graph, it can be estimated that this diameter is approximately 5 mm.
Figure 1: Minimum Plate Settler Spacing vs. Capture Velocity
Figure 2 shows the minimum particle size that will roll up the plate settler plotted against plate settler spacing. The line at the order of magnitue of colloidal particle size shows that at a plate settler spacing of approximately 17 mm and a tube diameter of 23 mm there should theoretically be no floc roll up
Figure 2: Plate Settler Spacing vs. Floc Diameter
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