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Experiments run in fall 2007 indicated that the float valve can hold back head of at least 8m with less than 0.5cm 5 cm of change occurring in the flow controller water level in the first 2m of pressure. In field tests in Honduras the flow controllers did as expected from theoretical modals, which current lab work is aiming to correct2 m of pressure. Data gathered in the laboratory on outflow rate has followed a linear model in the laminar flow range, but attempts to model the turbulent transition range have produced varying results. It is considered a high priority to develop a reliable model for dosing at higher flow rates, which will be used in the near future at the larger plant in Marcala, currently under constructionplants.

Keywords: Flow Controller, laminar flow, height of outflow, influent pressure, float valve

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Plastic bottle flow controllers have been used in Honduras for alum and chlorine dosing for several months now, and a few problems have arisen. They have been clogging and the head loss to alum dosing relationship does not appear linear. Further testing this during the fall of 2007 has been done with more precise equipment and an extra connector was removed from the flow controller to make it resemble the set up used in Honduras. The outflow to head loss relationship once again appears relatively linear in the laminar range, and it is possible that a different type of experiment should be designed to address the non-linear data from Honduras.

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