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The foam filtration unit will be 12 inches tall, with a foam depth of 10 inches. The foam will rest be resting on the bottom of a pvc pipe (with a screen included). Orifices will be drilled at screen, which will be a set height above the bottom of the pipe in order to maintain constant flow through the filter. The rate of water flowing into the unit should equal the rate of the water flowing out of the unit. In addition, we are looking into attaching the foam filtration unit directly to a faucet of some sort. As the filtered water exits through the bottom orifices, it will be collected by a bucket located beneath the filter itself. This water will then be treated with chlorine and either kept in a storage tank or sent to the distribution system depending on the number of people using the filtration unit.filter bed to prevent preferential flow. The flow rate through the filter will be kept constant by a small container attached to the filter bed. A float valve will monitor the level of water in this small container, and an orifice will deliver a constant flow rate to the filter bed. Additionally, it is important that water does not flow out of the filter and make the foam dry at any point when the filter is running. Therefore, the tube removing water from the filter will come up to a set height which is equal to the height of the water in the filter (see figure 1).
Figure 1: Filter Bed Schematic
Calculations for the dimensions for the filter bed can be found in a MathCAD file.