Patent ID: 7874431

Claim:
A filter element for cleaning a fluid, having a pleated filter medium designed for radial flow and having a reinforcing thread disposed circumferentially on the outside of the filter medium, wherein at least two axial sections are provided on the outside of the filter medium, in which the reinforcing thread is applied to the outside in a plurality of axially spaced circumferential thread windings, wherein directly adjacent thread windings in one axial section are spaced apart an axial distance which differs from the axial spacing of adjacent thread windings in the other axial section, the axial spacing in both sections being selected to prevent significantly increasing a flow resistance therethrough, wherein the axial section with the smaller spacing between adjacent thread windings extends over a shorter axial length than the other axial section with the larger spacing between adjacent thread windings, wherein the reinforcing thread follows a helically extending path around the outside of the filter medium and has a different thread pitch in the two axial sections, wherein said reinforcing thread is not a woven net or sheet, wherein a first portion of said reinforcing thread following said helically extending path does not overlap or contact another portion of said thread on an adjacent portion of said helically extending path, and wherein the axial spacing of adjacent thread windings differs in the two axial sections by a factor of 1.5 to 10.