Filter bag assembly

1. A filter bag assembly comprising an outer bag including an open end and a closed end opposite said open end and having a longitudinal axis, said open end being sized and shaped for receiving liquid to be filtered; and a filter member mounted in said outer bag and having a pair of opposed open ends and a plurality of longitudinally extending pleats, each of said pleats projecting generally outwardly in a radial direction; an inner sleeve disposed inside said filter member, said inner sleeve including a cover portion for covering one of the open ends of said filter member proximate the open end of said outer bag, wherein said inner sleeve and cover portion are constructed as a filtering layer; and a ring including a skirt attached to said open end of said outer bag and to a radially outer periphery of the cover portion of said inner sleeve, for supporting said filter bag assembly from an internal shoulder of a filter housing.

2. The filter bag assembly of claim 1 , wherein said filter member is substantially coaxial with respect to said outer bag.

3. The filter bag assembly of claim 2 , wherein each of said pleats extends between said open ends of said filter member.

4. The filter bag assembly of claim 3 , wherein said filter member has a generally cylindrical shape.

5. The filter bag assembly of claim 4 , wherein said filter member is self-supporting.

6. The filter bag assembly of claim 5 , wherein said filter member includes maintaining means for maintaining the pleated construction of said filter member.

7. The filter bag assembly of claim 6 , wherein said maintaining means includes a plurality of tags, each of which is connected to an adjacent pair of said pleats.

8. The filter bag assembly of claim 1 , wherein one of said open ends of said filter member is positioned adjacent to said ring, and the other of said open ends of said filter member is positioned adjacent to said closed end of said outer bag.

9. The filter bag assembly of claim 8 , further comprising an intermediate layer wrapped around said filter member and having a first end, which is attached to said ring, and a second end, which is positioned adjacent to said other one said open ends of said filter member.

10. The filter bag assembly of claim 9 , further comprising a cap mounted in said outer bag, said cap having an open end for receiving said other one of said open ends of said filter member proximate the closed end of said outer bag.

11. The filter bag assembly of claim 1 , wherein said filter member has a generally cylindrical shape.

12. The filter bag assembly of claim 1 , wherein said filter member is self-supporting.

13. The filter bag assembly of claim 1 , wherein said filter member includes maintaining means for maintaining the pleated construction of said filter member.

14. The filter bag assembly of claim 13 , wherein said maintaining means includes a plurality of tags, each of which is connected to an adjacent pair of said pleats.

15. The fitter bag assembly of claim 1 , wherein said filter member includes a filter sheet folded in a predetermined manner so as to form said pleats.

16. The filter bag assembly of claim 15 , wherein said filter sheet has a pair of longitudinal edges attached to one another such that the filter member is provided with a generally cylindrical shape, said filter member including a plurality of tags for loosely attaching said longitudinal edges of said filter sheet to one another.

17. The filter bag assembly of claim 16 , wherein said filter member includes an inner sheet and an outer sheet, said filter sheet being interposed between said inner and outer sheets, said inner and outer sheets being folded together with said filter sheet so as to form said pleats.

18. The filter bag assembly of claim 17 , wherein said pleats are kept separated by said inner and outer sheets.

19. The filter bag assembly of claim 18 , wherein said filter sheet is made from a flexible woven material.

20. The filter bag assembly of claim 19 , wherein said inner and outer sheets are made from a flexible non-woven material.

21. The filter bag assembly of claim 19 , wherein at least one of said inner and outer sheets is made from a flexible mesh material.

22. The filter bag assembly of claim 1 , wherein each of said pleats is slanted relative to a corresponding radial axis of said filter member such that it has at least one portion which overlaps with an adjacent one of said pleats.

23. The filter bag assembly of claim 22 , wherein each of said pleats includes first and second sides, each of said first sides having a size greater than that of a corresponding one of said second sides.

24. A filter bag assembly comprising an outer bag including an open end and a closed end opposite said open end and having a longitudinal axis, said open end being sized and shaped for receiving liquid to be filtered; and a self-supporting filter member having a generally cylindrical shape, said filter member mounted loosely in, and substantially coaxial with respect to, said outer bag and having a pair of opposed open ends and a plurality of longitudinally extending pleats, each of said pleats projecting generally outwardly in a radial direction and extending between said open ends of said filter member, said filter member including a plurality of tags for maintaining its pleated construction, each of said tags extending from an outer side of one of an adjacent pair of said pleats, penetrating through said one of said adjacent pair of said pleats and terminating at an inner side of the other one of said adjacent pair of said pleats.

25. A filter bag assembly comprising an outer bag including an open end and a closed end opposite said open end and having a longitudinal axis, said open end being sized and shaped for receiving liquid to be filtered; and a filter member mounted loosely in said outer bag and having a pair of opposed open ends and a plurality of longitudinally extending pleats, each of said pleats projecting generally outwardly in a radial direction, said filter member including a plurality of tags for maintaining its pleated construction, each of said tags extending from an outer side of one of an adjacent pair of said pleats, penetrating through said one of said adjacent pair of said pleats and terminating at an inner side of the other one of said adjacent pair of said pleats.

26. The filter bag assembly of claim 25 , wherein said filter member includes a filter sheet folded in a predetermined manner so as to form said pleats, said filter sheet having a pair of longitudinal edges, which are attached to one another.

27. The filter bag assembly of claim 26 , wherein said filter member includes a plurality of tags for loosely attaching said longitudinal edges of said filter sheet to one another.

28. The filter bag assembly of claim 27 , wherein said filter member includes an inner sheet and an outer sheet, said filter sheet being interposed between said inner and outer sheets, said inner and outer sheets being folded together with said filter sheet so as to form said pleats.

29. The filter bag assembly of claim 28 , wherein said pleats are kept separated by said inner and outer sheets.

30. The filter bag assembly of claim 29 , wherein said filter sheet is made from a flexible woven material.

31. The filter bag assembly of claim 30 , wherein said inner and outer sheets are made from a flexible non-woven material.

32. The filter bag assembly of claim 30 , wherein at least one of said inner and outer sheets is made from a flexible mesh material.

33. The filter bag assembly of claim 30 , wherein each of said pleats is slanted relative to a corresponding radial axis of said filter member.

34. The filter bag assembly of claim 33 , wherein each of said pleats includes first and second sides, each of said first sides a size greater than that of a corresponding one of said second sides.

35. The filter bag assembly of claim 25 , further comprising a sealing ring, said open end of said outer bag being attached to said sealing ring.