Filter elements for liquid filters

Claim 1

A filter unit comprising a filter element formed from a strip of sheet filter material having two lines of adhesive respectively applied to opposite faces of the strip adjacent opposite longitudinal edges thereof, the strip being folded about a series of regularly spaced fold lines extending transversely of the strip to form an assembly of accordion pleats, the two halves of each pleat being sealed to each other, at one end of the pleat, and, at the other end thereof, being sealed respectively to the adjacent halves of adjacent pleats to each side thereof, and the ends of said strip being secured and sealed to each other to form the assembly into a hollow tubular filter element; a combined center tube and end plate assembly having an annular end plate with a central flanged opening adapted to be fitted over a spigot in a filter head, and a center tube which extends coaxially from one face of said end plate; and a tubular casing having at one end thereof a centrally apertured base with an annular internal shoulder thereon adjacent the wall of the casing, said filter element being fitted over said center tube and sealed at its inner periphery at one end thereof to the angle between the end plate and center tube, the free ends of the pleats adjacent said one end being at the outer periphery of the element, and the assembled filter element, end plate and center tube being fitted within said casing with the other end of said element seated on said internal shoulder, the outer periphery of the element at said other end being sealed to the annular shoulder, and the outer periphery of said end plate being sealed to the casing at the other end thereof.