Filter element with high temperature polymer retaining straps and method of manufacture

1. A filter element comprising:

a filtration media formed into a tubular configuration and comprising a plurality of circumferentially spaced apart pleats;

a mounting structure at a first axial end of said filter element;

an end cap at a second axial end of said filter element, said filtration media extending between said mounting structure and said end cap; and

at least one melt-extruded retention strap extending circumferentially around said filtration media to limit radial movement of said filtration media at operating temperatures up to about 500° F., said at least one melt-extruded retention strap comprising a melt extrudable amorphous thermoplastic polyimide, and said at least one melt-extruded retention strap positioned between said first axial end of said filter element and said second axial end of said filter element;

said amorphous thermoplastic polyimide comprising a copolymer of, or a blend of, an amorphous thermoplastic polyimide polymer and another polymer selected from the group consisting of polyetherimide polymers and polyetherertherketone polymers.

2. A filter element in accordance with claim 1 wherein said copolymer or blend comprises about 40 percent to less than about 100 percent, by weight, of said amorphous thermoplastic polyimide polymer.

3. A filter element in accordance with claim 1 wherein said copolymer or blend comprises about 80 percent to less than about 100 percent, by weight, of said amorphous thermoplastic polyimide polymer.

4. A filter element in accordance with claim 1 wherein at least one of said plurality of pleats comprises a pair of substantially oblique sides forming at least one tip, said retention strap coupled to at least one of said tips.

5. A filter element in accordance with claim 4 wherein said at least one retention strap is coupled to at least one of said substantially oblique sides.

6. A filter element in accordance with claim 1 wherein said at least one retention strap comprises a portion extending between adjacent pleats.

7. A filter element in accordance with claim 1 wherein said at least one retention strap further comprises a reinforcement structure.

8. A filter element in accordance with claim 1 wherein at least one said melt-extruded retention strap extends circumferentially around said filtration media to limit radial movement of said filtration media at operating temperatures from about 375° F. to about 500° F.

9. A method of fabricating a filter element, said method comprising:

providing a filtration media formed into a tubular configuration and comprising a plurality of circumferentially spaced apart pleats;

coupling a mounting structure at a first axial end of the filter element; and

coupling an end cap at a second axial end of the filter element, the filtration media extending between the mounting structure and the end cap; and

extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media to form a retention strap that extends circumferentially around said filtration media to limit radial movement of said filtration media at operating temperatures up to about 500° F.

wherein the amorphous thermoplastic polyimide comprises a copolymer of, or a blend of, an amorphous thermoplastic polyimide polymer and another polymer selected from the group consisting of polyetherimide polymers and polyetherertherketone polymers.

10. A method in accordance with claim 9 wherein the copolymer or the blend comprises about 40 percent to less than about 100 percent, by weight, of the amorphous thermoplastic polyimide polymer.

11. A method in accordance with claim 9 wherein the copolymer or the blend comprises about 80 percent to less than about 100 percent, by weight, of the amorphous thermoplastic polyimide polymer.

12. A method in accordance with claim 9 wherein at least one of the plurality of pleats comprises a pair of substantially oblique sides forming at least one tip, said extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media comprises extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media so as to couple the retention strap to at least one of the tips.

13. A method in accordance with claim 12 wherein extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media comprises extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media so as to couple the retention strap to at least one of the oblique sides of the plurality of pleats.

14. A method in accordance with claim 9 wherein extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media comprises extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media so that the retention strap comprises a portion extending between adjacent pleats.

15. A method in accordance with claim 9 further comprises applying a reinforcement structure to the extruded amorphous thermoplastic polyimide to form a reinforced retention strap.

16. A method in accordance with claim 9 wherein extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media comprises extruding an amorphous thermoplastic polyimide circumferentially around a portion of the filtration media to form a retention strap that extends circumferentially around said filtration media to limit radial movement of said filtration media at operating temperatures from about 375° F. to about 500° F.