Feedthrough capacitor filter assemblies with leak detection vents

• US 6,566,978 B2
• Filed: 12/07/2000
• Issued: 05/20/2003
• Est. Priority Date: 09/07/2000
• Status: Expired due to Term

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch-Sierra, Inc.
• Inventors: Dobbs, Matthew A., Stevenson, Robert A.
• Primary Examiner(s): Bettendorf, Justin P.
• Application Number:
  US09/733,342
• Publication Number:
  US 20020027484A1
• Time in Patent Office: 894 Days
• Field of Search: 333/182, 333/183, 361/302, 607/36, 607/37
• US Class Current: 333/182
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 2/103 Sealings, e.g. for lead-in wires; Covers
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors

Abstract

A feedthrough capacitor filter assembly includes a capacitor having first and second sets of conductive electrode plates embedded within an insulative or dielectric body, and a leak detection vent for facilitated hermetic seal testing prior to use. At least one feedthrough terminal pin extends through the capacitor in conductive relative with the first set of electrode plates, and an outer ferrule is mounted about the capacitor in conductive relation with the second set of electrode plates. A hermetic seal is seated within the ferrule at one side of the capacitor to prevent leakage of fluid through the filter assembly. The hermetic seal is spaced from a face of the capacitor to form a gap therebetween.

Claims

1. A feedthrough capacitor filter assembly, comprising:

a capacitor body having first and second electrode plates encased therein in spaced relation, at least one terminal pin bore formed axially therethrough, and at least one leak detection passage extending axially therethrough;

at least one conductive terminal pin extending through said at least one terminal pin bore in conductive relation with said first electrode plate;

a conductive ferrule having at least one aperture formed axially therethrough, said capacitor body being mounted to said ferrule to extend across and close said at least one ferrule aperture with said second electrode plate in conductive relation with said ferrule; and

at least one hermetic seal formed from a dielectric material and extending across and sealing said at least one ferrule aperture at one axial side of said capacitor body, said at least one hermetic seal defining an inboard face presented toward said capacitor body and an outboard face presented away from said capacitor body, said at least one terminal pin extending through said at least one hermetic seal;

wherein said at least one leak detection passage vents said inboard face of said at least one hermetic seal.

2. The feedthrough capacitor filter assembly of claim 1, wherein said at least one hermetic seal and said capacitor body cooperatively define an axial gap formed therebetween.

3. The feedthrough capacitor filter assembly of claim 1, wherein said first and second electrode plates respectively comprise first and second sets of electrode plates encased in interleaved spaced relation within said capacitor body.

4. The feedthrough capacitor filter assembly of claim 1, wherein said capacitor body is formed from a substantially monolithic dielectric material.

5. The feedthrough capacitor filter assembly of claim 1, wherein said at least one terminal pin bore comprises a plurality of axially extending terminal pin bores formed in said capacitor body, and further wherein said at least one conductive terminal pin comprises a corresponding plurality of terminal pins extending respectively through said terminal pin bores and said at least one hermetic seal.

6. The feedthrough capacitor filter assembly of claim 5, wherein said at least one hermetic seal comprises a plurality of hermetic seals corresponding to a plurality of ferrule apertures.

7. The feedthrough capacitor filter assembly of claim 1, wherein one of said first and second electrode plates has an edge exposed within and lining said at least one leak detection passage.

8. The feedthrough capacitor filter assembly of claim 7, further including a conductive lining formed within said at least one leak detection passage.

9. The feedthrough capacitor filter assembly of claim 1, wherein said at least one leak detection passage is formed in said capacitor body in an axially centered position.

10. The feedthrough capacitor filter assembly of claim 1, wherein said at least one leak detection passage is formed in said capacitor body in an axially offset position.

11. The feedthrough capacitor filter assembly of claim 1, wherein said at least one leak detection passage is formed in said capacitor body as an offset enlargement of said at least one terminal pin bore.

12. The feedthrough capacitor filter assembly of claim 11, further including an insert member fitted within said at least one leak detection passage.

13. The feedthrough capacitor filter assembly of claim 12, wherein said insert member is removable.

14. The feedthrough capacitor filter assembly of claim 1, wherein said capacitor body has a generally discoidal shape.

15. The feedthrough capacitor filter assembly of claim 1, wherein said capacitor body has a generally rectangular shape.

16. The feedthrough capacitor filter assembly of claim 1, wherein said ferrule defines an internal shoulder for substantially nested reception of said capacitor body.

17. The feedthrough capacitor filter assembly of claim 1, including a dissolvable washer disposed between said at least one hermetic seal and said capacitor body to form an axial gap therebetween.

18. The feedthrough capacitor filter assembly of claim 1, further including conductive means for mounting said at least one terminal pin within said at least one terminal pin bore in conductive relation with said first electrode plate.

19. The feedthrough capacitor filter assembly of claim 1, including a plurality of axially extending terminal pin bores formed in said capacitor body, and at least one conductive ground pin extending into at least one of the plurality of axially extending terminal pin bores in conductive relation with said second electrode plate.

20. A feedthrough capacitor filter assembly, comprising:

a capacitor body formed from a dielectric material encasing first and second sets of electrode plates in an interleaved spaced array, at least one terminal pin bore formed axially therethrough, and at least one leak detection passage extending axially therethrough;

at least one conductive terminal pin extending through said at least one terminal pin bore in conductive relation with said first set of electrode plates;

a conductive ferrule having at least one aperture formed axially therethrough, said capacitor body being mounted to said ferrule to extend across and close said at least one ferrule aperture with said second set of electrode plates in conductive relation with said ferrule; and

at least one hermetic seal formed from a dielectric material and extending across and sealing said at least one ferrule aperture at one axial side of said capacitor body, said at least one hermetic seal defining an inboard face presented toward said capacitor body and an outboard face presented away from said capacitor body, said at least one terminal pin extending through said at least one hermetic seal;

said at least one hermetic seal and said capacitor body cooperatively defining an axial gap formed therebetween;

said at least one leak detection passage venting said gap.

21. The feedthrough capacitor filter assembly of claim 20, wherein said at least one terminal pin bore comprises a plurality of axially extending terminal pin bores formed in said capacitor body, and further wherein said at least one conductive terminal pin comprises a corresponding plurality of terminal pins extending respectively through said terminal pin bores and said at least one hermetic seal.

22. The feedthrough capacitor filter assembly of claim 21, wherein said at least one hermetic seal comprises a plurality of hermetic seals corresponding to a plurality of ferrule apertures.

23. The feedthrough capacitor filter assembly of claim 20, wherein one of said first and second electrode plates has an edge exposed within and lining said at least one leak detection passage.

24. The feedthrough capacitor filter assembly of claim 23, further including a conductive lining formed within said at least one leak detection passage.

25. The feedthrough capacitor filter assembly of claim 20, wherein said at least one leak detection passage is formed in said capacitor body as an offset enlargement of said at least one terminal pin bore.

26. The feedthrough capacitor filter assembly of claim 20, including a plurality of axially extending terminal pin bores formed in said capacitor body, and at least one conductive ground pin extending into at least one of the plurality of axially extending terminal pin bores in conductive relation with said second electrode plate.

27. The feedthrough capacitor filter assembly of claim 20, further including conductive means for mounting said capacitor body within said at least one ferrule aperture with said second set of electrode plates in conductive relation with said ferrule.

28. The feedthrough capacitor filter assembly of claim 20, further including conductive means for mounting said at least one terminal pin within said at least one terminal pin bore in conductive relation with said first set of electrode plates.

29. In a feedthrough capacitor filter assembly having a capacitor body with first and second electrode plates encased therein in spaced relation and at least one terminal pin bore formed axially therethrough, at least one conductive terminal pin extending through said at least one terminal pin bore in conductive relation with said first electrode plate, a conductive ferrule having at least one aperture formed axially therethrough, said capacitor body being mounted to said ferrule to extend across and close said at least one ferrule aperture with said second electrode plate in conductive relation with said ferrule, and at least one hermetic seal formed from a dielectric material and extending across and sealing said at least one ferrule aperture at one axial side of said capacitor body, said at least one hermetic seal defining an inboard face presented toward said capacitor body and an outboard face presented away from said capacitor body, said at least one terminal pin extending through said at least one hermetic seal, the improvement comprising:

means for venting said inboard face of said at least one hermetic seal, wherein said capacitor body has at least one leak detection passage extending axially therethrough, said leak detection passage forming at least a portion of said venting means.

30. The improvement of claim 29, wherein said hermetic seal and said capacitor body cooperatively define an axial gap formed therebetween, said axial gap forming at least a portion of said venting means.

31. The improvement of claim 30, wherein said first and second electrode plates respectively comprise first and second sets of electrode plates encased in interleaved spaced relation within said capacitor body.

32. The improvement of claim 29, wherein one of said first and second electrode plates has an edge exposed within the lining said at least one leak detection passage.

33. The improvement of claim 32, further including a conductive lining formed within said at least one leak detection passage.

34. The improvement of claim 29, wherein said at least one leak detection passage is formed in said capacitor body as an offset enlargement of said at least one terminal pin bore.

35. The improvement of claim 34, further including an insert member fitted within said at least one leak detection passage.

36. The improvement of claim 35, wherein said insert member is removable.

37. A feedthrough filter capacitor, comprising:

a capacitor body having first and second electrode plates encased therein in spaced relation, and at least one terminal pin bore formed axially therethrough;

said capacitor body having at least one leak detection passage extending axially therethrough.

38. The feedthrough filter capacitor of claim 37, wherein said first and second electrode plates respectively comprise first and second sets of electrode plates encased in interleaved spaced relation within said capacitor body.

39. The feedthrough filter capacitor of claim 37, wherein said capacitor body is formed from a substantially monolithic dielectric material.

40. The feedthrough filter capacitor filter of claim 37, wherein said at least one terminal pin bore comprises a plurality of axially extending terminal pin bores formed in said capacitor body.

41. The feedthrough filter capacitor of claim 37, wherein one of said first and second electrode plates has an edge exposed within and lining said at least one leak detection passage.

42. The feedthrough filter capacitor of claim 41, further including a conductive lining formed within said at least one leak detection passage.

43. The feedthrough filter capacitor of claim 37, wherein said at least one leak detection passage is formed in said capacitor body in an axially centered position.

44. The feedthrough filter capacitor of claim 37, wherein said at least one leak detection passage is formed in said capacitor body in an axially offset position.

45. The feedthrough filter capacitor of claim 37, wherein said at least one leak detection passage is formed in said capacitor body as an offset enlargement of said at least one terminal pin bore.

46. The feedthrough filter capacitor of claim 45, further including an insert member fitted within said at least one leak detection passage.

47. The feedthrough filter capacitor of claim 46, wherein said insert member is removable.

48. The feedthrough filter capacitor of claim 37, wherein said capacitor body has a generally discoidal shape.

49. The feedthrough filter capacitor of claim 37, wherein said capacitor body has a generally rectangular shape.

50. A feedthrough capacitor filter assembly, comprising:

a capacitor body having first and second electrode plates encased therein in spaced relation, a plurality of terminal pin bores formed axially therethrough, and at least one leak detection passage extending axially therethrough;

at least one conductive terminal pin extending through at least one of the terminal pin bores in conductive relation with said first electrode plate;

a conductive ferrule having at least one aperture formed axially therethrough, said capacitor body being mounted to said ferrule to extend across and close said at least one ferrule aperture with said second electrode plate in conductive relation with said ferrule; and

at least one hermetic seal formed from a dielectric material and extending across and sealing said at least one ferrule aperture at one axial side of said capacitor body, said at least one hermetic seal defining an inboard face presented towards said capacitor body and an outboard face presented away from said capacitor body, said at least one terminal pin extending through said hermetic seal, wherein said at least one hermetic seal and said capacitor body cooperatively define an axial gap formed therebetween.

51. The feedthrough capacitor filter assembly of claim 50, including a washer disposed between said at least one hermetic seal and said capacitor body.

52. The feedthrough capacitor filter assembly of claim 51, wherein said washer is dissolvable.

53. The feedthrough capacitor filter assembly of claim 50, including at least one conductive ground pin extending into at least one of the plurality of terminal pin bores in conductive relation with said second electrode plate.

54. The feedthrough capacitor filter assembly of claim 50, including a ground pin abutting and in conductive relation with both the ferrule and a conductive surface of the capacitor body.

55. The feedthrough capacitor filter assembly of claim 54, wherein the capacitor body includes a notch for receiving at least a portion of the ground pin therein, the notch including surface metallization for conductively coupling the ground pin to the second electrode plate.

56. The feedthrough capacitor filter assembly of claim 50, wherein the first and second electrode plates respectively comprise first and second sets of electrode plates encased in interleaved spaced relation within said capacitor body, and wherein said capacitor body is formed from a substantially monolithic dielectric material.

57. The feedthrough capacitor filter assembly of claim 50, wherein said at least one leak detection passage vents said gap.