Patent ID: 6159316
Filing Date: 2000-12-12
Classification: B01D,Y10S,Y10T

Abstract:
A method of making a gas filter element, the gas filter element having opposed first and second ends, and having parallel pockets extending longitudinally between the first and second ends, the method comprising:advancing two elongated webs of synthetic fibre material to a work station to lie on opposite sides of an ultrasonic welding unit;advancing parallel strips of fusible material to extend generally parallel to each other and to be positioned between the webs and substantially at right angles to the major axis of the webs;passing the strips through a former to fold up parts of said strips to define longitudinal marginal portions of said strips that lie on the inner surfaces of respective webs,passing the webs and the strip marginal portions past the ultrasonic welding unit so as to ultrasonically weld said strip marginal portions to said respective webs and to so connect each of, said strips to said webs to form bridging portions in between opposite sides of said webs, and sealing side edges of said webs;cutting across said webs and sealing the leading end portion of said webs to form a gas filter element and to separate it from said webs, said gas filter element having a first closed end and a second open end; and,forming cuts in said strips at said second open end of said gas filter for a depth sufficient to form two longitudinal side flaps of each said strip between said webs and double sealing said side flaps to said web.