Filter structure with two or more fine fiber layers with an extended period of use

摘要

The use of fine fiber of fiber having a fiber diameter of about 0.0001 to 0.5 microns has become an important design tool for filter media. Common filter media have been prepared with a layer of fine fiber on typically formed the upstream or intake side of the media structure. The fine fiber increases the efficiency of filtration by trapping small particles which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency but a substantial improvement in lifetime.