Patent ID: 7255300

Claim:
A method for forming a filter element having a coiled web of fluted filter media, wherein the web of fluted filter media is fed in a feed direction along a feed path to a mandrel, and the fluted filter media includes a plurality of flutes forming alternating peaks and valleys extending transverse to the feed direction and defining a pitch of the web, the method comprising: feeding out a length of the web in the feed direction; severing the web a first time by cutting through the web at one of the peaks of the fluted filter material to form a leading edge of the web; attaching the leading edge of the web to the mandrel; feeding the web of fluted filter media at a controlled linear speed onto the mandrel while rotating the mandrel with a winding motor providing a controlled driving torque to the mandrel, to thereby maintain a controlled tension on the web of fluted filter media as the web is wound onto the mandrel; while driving the mandrel with a controlled driving torque, feeding out a length of web equal to an integer multiple of the pitch of the web; severing the web a second time by cutting through the web at a peak of the fluted filter material to form a trailing edge of the web; severing the web the first and second time with a cutter disposed at a fixed location along the feed path, with respect to the mandrel; and applying an adhesive sealant to the web at a point located along the feed path between the cutter and the mandrel and spaced beyond an over-feed distance from the cutter in the feed direction, with the over-feed distance being equal to an integer multiple of the pitch of the web.