If a pressure tank is used, the air-water contact in the pressure tank can lead to bacterial growth in the tank, clogging the emitter. The use of an air bladder or diaphragm to separate the air from the water should minimize this problem. Filters For Prevention of Plugging Many adequately performing types of microirrigation filter systems are available commercially. Important factors to consider in selecting a filtering method are emitter design and quality of the water source. Consider the emitter's minimum passageway diameter when selecting the filter mesh size.
Screen filters come in a variety of shapes and sizes.
A typical design is shown in Figure 1. Screen material may be slotted PVC, perforated stainless steel, or synthetic or stainless steel wire. To avoid floating debris, the pump inlet should be located two feet below the water surface but suspended above the bottom. Screen filters remove relatively small amounts of sands and organic material before clogging and causing a flow rate reduction. Two or more fitters installed in parallel will increase the time between screen cleanings.