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Non-uniform flow distribution in a typical feedwell Large feedwell with no uniform flow Typical problems with bustle pipes


The function of the clarifier is to settle out particles. This can be done by properly recognizing that small turbulence levels can bring particles together to help them settle more easily and that the effect of shear and strong turbulence levels will break particles leading to an increase in turbidity. Modeling of the shear velocities in feedwells show that too much swirl is imparted to the flow. The swirl will draw flow into the feedwell. The results is to create too much radial and axial momentum which increases turbidity. The problem is compounded by the fact that most bustle pipes do not pull flow equally in all holes, as shown in the above figures. PSL models the feedwell and bustle pipes. A complete retrofit design which is manufactured at low cost is then provided to bring clients a simple and cost effective way to reduce turbidity without increasing tank size. The solution addresses the fundamental problem with clarifier designs while keeping retrofit costs low.