US Patent 7442221 Filter element

A filter element, particularly a secondary element for a filter system in the intake tract of an internal combustion engine, which filter element includes a zig-zag pleated filter medium surrounded by a circumferential frame of polyurethane foam. The frame has a substantially oval contour and is insertable into an oval opening. To reproduce the oval contour, the plate-like medium has beveled lateral regions, such that a maximum effective filter surface is obtained with a minimum amount of waste. A circumferential groove or a circumferential web is provided in the frame to seal the polyurethane foam frame to the opening.