Electronic enclosures are often sealed against water and contaminants, but this can lead to pressure differentials between the interior and exterior that cause problems. For example, lower pressure inside the enclosure can pull water and air in, damage the seals, and wreak havoc on the electronics. To prevent this problem, engineers at W.L. Gore & Associates Inc., Elton, Md., developed a protective vent, the PolyVent D3, that lets air pass in and out, but keeps water, dust, insects, and debris from getting in.
The vent has a press-fit width of 2.5 mm and gas-flow capacity of 7 ml/min. The housing is polypropylene and contains an ePTFE membrane. This membrane lets gases pass through while keeping out contaminants. The vent works in temperatures from –4 to 212°F. The vent takes up no space inside enclosures and its low-profile exterior portion reduces the risk of damage from technicians who service the enclosure.