Filter elements for liquid filters

Claim 2

A filter element comprising a strip of sheet filter paper material folded on itself about a center longitudinal line to bring the two halves of the inner face of the strip together, the strip further being folded in a series of regularly spaced lines extending transversely of the strip to form the strip into a series of accordion pleats, the outside face of said strip having applied thereto adjacent each longitudinal edge thereof an adhesive by which on each half of the strip, the free edge of one-half of each pleat is sealed to the free edge of an apposed half of an adjacent pleat, one-half of each end portion of the folded strip being sealed to the apposed other half thereof adjacent the end edges of the strip thereby forming a zigzag pocket.

Claim 3

A filter unit, comprising a strip of sheet filter paper material folded on itself about a centerline to bring the inner faces of the strip together, the strip also being folded about a series of regularly spaced lines extending transversely of the centerline of the strip to form the strip into a series of accordion pleats, the edges of the outside faces of said strip on opposite sides of the centerline having an adhesive applied thereto, by which the free edge of each accordion pleat is sealed to the free outside edge of an apposed half of an adjacent pleat, with one-half of each end portion of the folded strip being sealed to an apposed other half thereof adjacent the outside end edges of the strip to form a zigzag pocket, said folded strip having its opposite ends sealed to each other to form the assembly into a hollow tubular element, the inner periphery of said tubular element being sealed to a tubular spigot and the outer periphery of said tubular element being sealed to The wall of a casing which surrounds said element, so that a liquid admitted to the element at the end thereof opposite that which includes the central fold of the strip can pass from the inner to the outer sides of the zigzag pocket.

Claim 4

A filter unit, comprising a strip of sheet filter paper material folded on itself about a centerline to bring the inner faces of the strip together, the strip also being folded about a series of regularly spaced lines extending transversely of the centerline of the strip to form the strip into a series of accordion pleats, the edges of the outside faces of said strip on opposite sides of the centerline having an adhesive applied thereto, by which the free edge of each accordion pleat is sealed to the free outside edge of an apposed half of an adjacent pleat, with one-half of each end portion of the folded strip being sealed to an apposed other half thereof adjacent the outside end edges of the strip to form a zigzag pocket, said folded strip having its opposite ends sealed to each other to form the assembly into a hollow tubular element, the inner periphery of said tubular element being sealed to a tubular spigot and the outer periphery of said tubular element being sealed to The wall of a casing which surrounds said element, so that a liquid admitted to the element at the end thereof opposite that which includes the central fold of the strip can pass from the inner to the outer sides of the zigzag pocket.

Claim 5

A filter unit according to claim 2, in which said casing is a hollow member having an annular base with a double passageway formed therein on which the end of the filter element is seated, said double passageway creating a tortuous path to the filtered liquid to obtain more complete filtration.

Claim 6

A filter unit according to claim 3 having a spigot at the end opposite said annular base, said spigot having a radial flange which is spaced inwardly from said annular base in the path of fluid flow so as to form therewith a flow passage by which filtered liquid is directed radially outwardly from the base of said casing toward said spigot.

Claim 7

A filter unit according to claim 2, in which said spigot has extending from the end thereof adjacent the sealed ends of the pleats a radial flange which overlies and is sealed to the inner and outer periphery of the element and is sealed at its outer periphery to said casing, said flange having openings intermediate its inner and outer peripheries to allow the entry of liquid to the ends of the pleats.