Claims for Patent: 6,846,412

Summary for Patent: 6,846,412

Title:	Combination filter assembly
Abstract:	A combination filter assembly having a plurality of filter sieves positioned in parallel one after the other in the direction of flow. The filter sieves are stretched and mounted in housing elements to form filter elements. The housing elements are in contact with each other by means of top and bottom bearing faces, and are maintained in a stack. The filter elements have a cylindrical shape with annular bearing faces, wherein one bearing face includes a centering male coupling and sealing formation, and the other bearing face includes a corresponding centering female coupling and sealing formation.
Inventor(s):	Hogan; Brendan (Limerick, IE), Myers; Jan Willem Marinus (Venlo, NL)
Assignee:	BTG International Limited (London, GB)
Application Number:	10/166,162
Patent Claims:	1. A combination filter assembly having a number of filter sieves, said filter sieves being positioned in parallel one after the other in the direction of flow, wherein the filter sieves are stretched and mounted in housing elements to form filter elements, wherein the housing elements, by means of top and bottom bearing faces, are in contact with each other and are maintained in a stacked arrangement, wherein the filter elements each comprise a cylindrical shape with annular bearing faces, wherein each filter element on either its top or bottom bearing face comprises a centering male coupling and sealing formation, and on the other of its top or bottom bearing face comprises a corresponding centering female coupling and sealing formation, wherein the male coupling and sealing formation comprises an annular protrusion and the female coupling and sealing formation comprises a corresponding annular groove, and wherein the filter elements are positioned as a coaxial stack and are substantially enclosed within a housing. 2. The combination filter assembly according to claim 1, wherein the annular protrusion and the annular groove each have a V-shaped cross-section. 3. The combination filter assembly according to claim 1, wherein one of either the top or bottom bearing face further comprises an annular lowered step, and the other of the top or bottom bearing face further comprises an annular boss configured to fit into said step, wherein the fit between an exterior diameter of the boss and an interior diameter of the step is a slight press fit, that the male coupling and sealing formation is positioned on the top of the step, that the female coupling and sealing formation is positioned on the corresponding top of the boss, and that a height of the boss is larger than a depth of the step. 4. The combination filter assembly according to claim 1, wherein the filter sieve is positioned over the annular protrusion in the corresponding housing element and partly covers the cylindrical wall surrounding the step. 5. The combination filter assembly according to claim 1, wherein the combination filter assembly comprises two to five filter elements. 6. The combination filter assembly according to claim 1, wherein the filter elements are mounted in the housing with an axial load and, that the housing comprises an entry section and an exit section, said entry section and said exit section being mountable to each other in an axial relationship, wherein the entry section includes a female coupling and sealing formation and the exit section includes a male coupling and sealing formation. 7. The combination filter assembly according to claim 6, wherein the entry section is connected with the exit section while maintaining the axial load of the coaxial stack of filter elements by ultrasonic welding or adhesion. 8. The combination filter assembly according to claim 6, wherein the entry section is connected with the exit section while maintaining the axial load in the coaxial stack of filter elements by a cylinder section produced by overmoulding the entry and exit sections. 9. The combination filter assembly according to claim 8, wherein the cylinder section comprises an artificial resin that shrinks after overmoulding to produce said axial load in the coaxial stack of filter elements. 10. The combination filter assembly according to claim 8, wherein the housing elements have a wall thickness such that the material thereof is melted together with the material of the cylinder section during overmoulding. 11. The combination filter assembly according to claim 6, wherein the entry section comprises a female Luer-Lock connector. 12. The combination filter assembly according to claim 6, wherein the exit section comprises a male Luer-Lock connector. 13. The combination filter assembly according to claim 1, wherein the filter sieves of the plurality of filter elements each have the same pore size. 14. The combination filter assembly according to claim 1, wherein the filter sieves of the plurality of filter elements have different pore sizes so as to form a depth filter. 15. The combination filter assembly according to claim 1, wherein the filter sieves each comprise a filtering portion and an annularly disposed mounting portion, the mounting portion being substantially supported by the housing element, and the filtering portion being substantially unsupported by the housing element. 16. The combination filter assembly according to claim 15, wherein the filtering portion of the filter sieve is disposed within a single plane. 17. The combination filter assembly according to claim 15, wherein the filtering portion of the filter sieve comprises an area that is larger than that of the mounting portion. 18. A combination filter assembly having a number of filter sieves, said filter sieves being positioned in parallel one after the other in the direction of flow, wherein the filter sieves are stretched and mounted in housing elements to form filter elements, wherein the housing elements, by means of top and bottom bearing faces, are in contact with each other and are maintained in a stacked arrangement, wherein the filter elements each comprise a cylindrical shape with annular bearing faces, wherein each filter element on either its top or bottom bearing face comprises a centering male coupling and sealing formation, and on the other of its top or bottom bearing face comprises a corresponding centering female coupling and sealing formation, wherein the male coupling and sealing formation comprises an annular protrusion and the female coupling and searing formation comprises a corresponding annular groove, wherein the filter elements are positioned as a coaxial stack within a housing, that the filter elements are mounted in the housing with an axial load and, that the housing comprises an entry section and an exit section, said entry section and said exit section being mountable to each other in an axial relationship, and wherein the entry section includes a female coupling and sealing formation and the exit section is includes a male coupling and sealing formation. 19. The combination filter assembly according to claim 18, wherein the annular protrusion and the annular groove each have a V-shaped cross-section. 20. The combination filter assembly according to claim 18, wherein on of either the top or bottom bearing face further comprises an annular lowered step, and the other of the top or bottom bearing face further comprises an annular boss configured to fit into said step, wherein the fit between an exterior diameter of the boss and an interior diameter of the step is a slight press fit, that the male coupling and sealing formation is positioned on the top of the step, that the female coupling and sealing formation is positioned on the corresponding top of the boss, and that a height of the boss is larger than a depth of the step. 21. The combination filter assembly according to claim 18, wherein the filter sieve is positioned over the annular protrusion in the corresponding housing element and partly covers the cylindrical wall surrounding the step. 22. The combination filter assembly according to claim 18 wherein the combination filter assembly comprises two to five filter elements. 23. The combination filter assembly according to claim 18, wherein the entry section is connected with the exit section while maintaining the axial load of the coaxial stack of filter elements by ultrasonic welding or adhesion. 24. The combination filter assembly according to claim 18, wherein the entry section is connected with the exit section while maintaining the axial load in the coaxial stack of filter elements by a cylinder section produced by overmoulding the entry and exit sections. 25. The combination filter assembly according to claim 18, wherein the cylinder section comprises an artificial resin that shrinks after overmoulding to produce said axial load in the coaxial stack of filter elements. 26. The combination filter assembly according to claim 18, wherein the housing elements have a wall thickness such that the material thereof is melted together with the material of the cylinder section during overmoulding. 27. The combination filter assembly according to claim 18, wherein the entry section comprises a female Luer-Lock connector. 28. The combination filter assembly according to claim 18, wherein the exit section comprises a male Luer-Lock connector. 29. The combination filter assembly according to claim 18, wherein the filter sieves of the plurality of filter elements each have the same pore size. 30. The combination filter assembly according to claim 18, wherein the filter sieves of the plurality of filter elements have different pore sizes so as to form a depth filter. 31. A method for producing a combination filter assembly comprising a number of filter sieves that are stretched and mounted in housing elements to thereby form filter elements, said filter sieves being positioned in parallel one after the other in the direction of flow, said housing elements being positioned by means of top and bottom bearing faces in contact with each other so as to form a stack within a housing, wherein each filter element is provided with a centering male coupling and sealing formation on one of its bearing faces, and is provided with a centering female coupling and sealing formation on its opposite bearing face, said method comprising the steps of: a) stacking the filter elements with interengaging male and female sealing formations to form a column; b) positioning the column of filter elements between an entry section and an exit section; c) axially compressing the column of fitter elements; and d) connecting the entry section with the exit section via a housing section so as to enclose the filter elements. 32. The method according to claim 31, wherein the entry section is connected with the exit section via the housing section by means of ultrasonic welding or adhesion. 33. The method according to claim 31, wherein the entry section is connected with the exit section by overmolding. 34. The method according to claim 33, wherein the column of filter elements is positioned between the entry section and the exit section under a prehensile load, and wherein the entry section is connected with the exit section by means of a cylindrical section formed by overmoulding. 35. The method according to claim 34, wherein the wall thickness of the filter elements is chosen so that the material of the cylinder section is melted together with the material of the filter elements during overmoulding. 36. The method according to claims 34, wherein the wall thickness the housing elements is chosen so that the material of the cylinder section is melted together with the material of the housing elements during overmoulding. 37. The method according to claim 34, wherein the injection molding temperature is chosen so that the material of the cylinder section is melted together with the filter elements or the housing elements during overmoulding. 38. A method for producing a combination filter assembly comprising a number of filter sieves that are stretched and mounted in housing elements to thereby form filter elements, said filter sieves being positioned in parallel one after the other in the direction of flow, said housing elements being positioned by means of top and bottom bearing faces in contact with each other so as to form a stack within a housing, wherein each filter element is provided with a centering male coupling and sealing formation on one of its bearing faces, and is provided with a centering female coupling and sealing formation on its opposite bearing face, said method comprising the steps of: a) stacking the filter elements with interengaging male and female sealing formations to form a column; b) positioning the column of filter elements between an entry section and an exit section; c) axially compressing the column of filter elements; and d) connecting the entry section with the exit section via a housing section by means of ultrasonic welding or adhesion. 39. A method for producing a combination filter assembly comprising a number of filter sieves that are stretched and mounted in housing elements to thereby form filter elements, said filter sieves being positioned in parallel one after the other in the direction of flow, said housing elements being positioned by means of top and bottom bearing faces in contact with each other so as to form a stack within a housing, wherein each filter element is provided with a centering male coupling and sealing formation on one of its bearing faces, and is provided with a centering female coupling and sealing formation on its opposite bearing face, said method comprising the steps of: a) stacking the filter elements with interengaging male and female sealing formations to form a column; b) positioning the column of filter elements between an entry section and an exit section; c) axially compressing the column of filter elements; and d) connecting the entry section with the exit section by overmolding. 40. The method according to claim 39, wherein the column of filter elements is positioned between the entry section and the exit section under a prehensile load, and wherein the entry section is connected with the exit section by means of a cylindrical section formed by overmoulding. 41. The method according to claim 40, wherein the wall thickness of the filter elements is chosen so that the material of the cylinder section is melted together with the material of the filter elements during overmoulding. 42. The method according to claim 40, wherein the wall thickness the housing elements is chosen so that the material of the cylinder section is melted together with the material of the housing elements during overmoulding. 43. The method according to claim 40, wherein the injection molding temperature is chosen so that the material of the cylinder section is melted together with the filter elements or the housing elements during overmoulding.