Patent ID: 7828155

Claim:
A method for the manufacture of a filter cartridge, said filter cartridge consisting of a tubular filter element capped at first and second ends with a thermoplastic end cap fixed to the first and second ends at first and second interlock zones respectively, the method comprising the steps of: (a) providing a die mold having an inner mold cavity with an inner mold surface, a supply duct connected to said inner mold cavity, the inner mold cavity having a region thereof shaped to substantially conform to the outer contours of a thermoplastic end cap; (b) providing a tubular filter element comprising a porous or fibrous material and having a first end having a first outer peripheral leading edge, and a second end having a second leading outer edge; (c) inserting said tubular filter element into the inner mold cavity, prior to injecting a molten thermoplastic material, such that said first end having a first leading edge does not contact the inner mold surface but is within said region of the mold conforming to the outer contours of said thermoplastic end cap; (d) injecting a sufficient quantity of molten thermoplastic material through said supply duct into said inner mold cavity to fill said region of the mold conforming to the outer contours of said thermoplastic end cap, said molten thermoplastic material coming into direct contact with the first outer peripheral leading edge of the first end of said tubular filter element, infiltrating and flowing into and around the first end of the tubular filter element; (e) forming the thermoplastic end cap and a first interlock zone in the first end of the tubular filter element to mechanically secure together the thermoplastic end cap to the first end of the tubular filter element; and (f) removing the end capped tubular filter element from said die mold after said molten thermoplastic material has sufficiently cured; wherein said thermoplastic material has a thermal melt temperature substantially below the thermal melt temperature of the tubular filter element.