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The Poly-Boss Polymer Control System
| Thickeners are often difficult to control manually because the settling rate of any material changes with particle size distribution, concentration of suspended solids, specific gravity, and polymer dosage. Most thickener operations experience changes in all of these variables, and in addition, the feed rate to the thickener is seldom constant. Consequently, it is very difficult to achieve desired performance of the thickener using manual adjustments. Overflow clarities, thickener bed levels, and underflow densities are constantly varying outside of desired ranges. And since most operators use an overdose of polymer to insure that the dosage is high enough to handle variations that the operators cannot anticipate or observe between manual adjustments, polymer is often wasted. If the polymer dosage is constantly monitored and adjusted to achieve uniform settling characteristics, steady-state operation of the thickener becomes much easier. Cost savings are also achieved due to reduced polymer costs, a lower frequency of thickener upsets, and consistent achievement of desired overflow and underflow characteristics. |
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The WesTech Poly-Boss uses state-of-the-art technology to monitor and control the polymer dosage to actual requirements. Savings of 30% to 70% in polymer consumption are achievable, and because the overflow and underflow characteristics consistently meet design requirements, additional cost savings are achieved in improved productivity and increased profits. Thickener upsets due to high thickener torque, variable underflow densities, and dirty overflows are minimized.
The WesTech Poly-Boss solves thickener operating problems efficiently and economically. Samples of flocculated slurry are automatically taken and measured for settling characteristics. Concentration of solids and settling rates are measured and correlated. Polymer dosage is automatically adjusted to provide desired underflow concentration and overflow clarity. |
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The WesTech Poly-Boss is installed on the bridge of the thickener. A settling column sampling hose is immersed in the feedwell or flocculation tank. Samples of slurry are drawn into the column under vacuum so that the flocculation is undisturbed. The density and settling characteristics are measured without having to bring the sample in contact with measurement devices that can scale over or become plugged. The sample is then purged, the settling column is flushed, and a new sample is taken. In the meantime, the settling characteristics of the slurry are analyzed, and the polymer dosage is adjusted to provide either constant settling velocity or uniform thickener unit area, depending on an operator controlled selection. Other parameters such as recent data history, settling rate, sample density, and others are available to provide the operator with valuable performance information.
To find out more about the WesTech Poly-Boss and other sedimentation and dewatering products and services, contact WesTech Engineering, Inc. We specialize in solving thickening, clarification, filtration, and other dewatering problems. |
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