A filter element for filtering a fluid is provided with a filter bellows made of a filter medium folded along fold edges in a zigzag shape to form folds, wherein the folds extend between oppositely positioned end face edges of the filter bellows. The filter bellows defines a raw side and a clean side of the filter element, wherein a fluid to be filtered flows from the raw side to the clean side. The filter medium has faces that are flowed through by the fluid to be filtered. The filter medium is provided at least on one of the faces that are flowed through with beads extending transversely to the fold edges. In a proper operating state of the filter bellows, the beads effect a flow of at least a portion of the fluid to be filtered in a direction perpendicular to the fold edges.

The invention relates to a filter manufacturing apparatus including a feed path adapted to continuously feed a filter material along a longitudinal transport direction, and a forming device connected to a terminating end of the feed path and adapted to form the filter material into a rod-shaped continuous filter body and deliver the formed continuous filter body. The forming device includes: a tubular element adapted to allow the filter material to pass therethrough to form the filter material into the continuous filter body; a heat source adapted to heat the filter material passing in the tubular element. A diameter measuring device is positioned at the outlet of the forming device and adapted to measure a diameter of the continuous filter body.

A pleated filter preparation system is provided for accurately counting pleats along a continuous sheet of pleated filter material and cutting the sheet into filter strips to be formed into filters. The pleated filter preparation system includes a pleat driver having multiple drive gears that engage with the pleats of the pleated filter material to move the pleated filter material through the system. A pleat counter counts peaks and valleys of each pleat comprising the pleated filter material so as to identify a target pleat to be cut. The pleat counter clamps and stretches the target pleat to distinguish the target pleat among the other pleats. A punch cut station cuts the target pleat to form a filter strip having a desired number of pleats. A pleat compressor compresses the filter strips to a predetermined size and then ejects the filter strips into a suitable container or bin.

A planar first medium in web form is produced or provided, having a first carrier layer including a first nonwoven fabric at least partially coated with an electrically conductive material. A planar second medium in web form is produced or provided, including a second carrier layer that comprises a second nonwoven fabric at least partially coated with an electrically conductive material. The first medium comprises a first filter layer arrangement connected to the first carrier layer, and/or the second medium comprises a second filter layer arrangement connected to the second carrier layer. The first medium and the second medium are amalgamated to obtain a layer composite in web form, such that the first filter layer arrangement and/or the second filter layer arrangement are at least partially arranged between the first carrier layer and the second carrier layer. A portion of the layer composite is separated thereby obtaining a filter element.

A pleated filter preparation system is provided for accurately counting pleats along a continuous sheet of pleated filter material and cutting the sheet into filter strips to be formed into filters. The pleated filter preparation system includes a pleat driver having multiple drive gears that engage with the pleats of the pleated filter material to move the pleated filter material through the system. A pleat counter counts peaks and valleys of each pleat comprising the pleated filter material so as to identify a target pleat to be cut. The pleat counter clamps and stretches the target pleat to distinguish the target pleat among the other pleats. A punch cut station cuts the target pleat to form a filter strip having a desired number of pleats. A pleat compressor compresses the filter strips to a predetermined size and then ejects the filter strips into a suitable container or bin.