摘要 |
Air filter elements with primary filter medias have foam pre-cleaners with an increased surface area provided by an upstream face which has peaks and valleys. In one embodiment, the peaks and valleys are defined by parallel ribs. If the filter element is a panel-type filter element having a pleated primary filter media, then, in accordance with one embodiment, the pre-cleaner is secured to the primary filter media by adhesive deposits on the peaks of the primary filter media. If the filter element is annular, the pre-cleaner is also annular and is slid axially over a perforated sleeve or screen on the primary filter media and held thereon by friction. By having the upstream surface of the foam pre-cleaner configured in peaks and valleys, the surface area of the upstream surface is increased substantially, which improves the capacity, efficiency and life of the filter element.
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