Filter Bed Design

The foam filtration unit will be 12 inches tall, with a foam depth of 10 inches. The foam will be resting on a screen, which will be a set height above the bottom of the 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.