Patent ID: 8105408

Claim:
An air operated brake control valve comprising an enclosure and a pressure equalization device mounted to a bore in a wall of the enclosure, the pressure equalization device comprising: a carrier with seals to being sealingly inserted in the bore; a first air passage in the carrier which provides a fluid communication between an interior of the enclosure and atmosphere; a barrier wall including an air permeable membrane that provides filtration of particulates for air entering the enclosure from the atmosphere, the barrier wall being sealably mounted to the carrier at a first face of the barrier wall that is most proximate to the atmosphere and extending across the entire cross section of the first passage the first passage is orthogonal to the entering air flow from the atmosphere, the barrier wall having a second, opposite face being most proximate to the interior of the enclosure and extending from the walls of the first air passage across a portion of the first air passage so as to have an area subject to the air flow in the first passage which is greater than the cross-sectional area of the first air passage at the first face; a second air passage in the carrier in parallel with a portion of the first air passage in the carrier for venting the enclosure; and the second air passage including a one-way vent valve adapted to permit air flow out of the enclosure through the second air passage but to prevent air flowing into the enclosure through the second air passage.