Method and apparatus for attenuating compressor noise

• US 20050166921A1
• Filed: 03/23/2005
• Published: 08/04/2005
• Est. Priority Date: 08/04/2003
• Status: Active Grant

• Current Assignee: Vyaire Medical 203 Incorporated (Cardinal Health, Inc.)
• Original Assignee: Pulmonetic Systems Incorporated (Cardinal Health, Inc.)
• Inventors: DeVries, Douglas F., Williams, Malcolm R.
• Granted Patent: US 7,527,053 B2
• Time in Patent Office: Days
• US Class Current: 128/204.210
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/0063 Compressors
• CPC Class Codes: A61M 16/0066 Blowers or centrifugal pumps
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 2205/42 Reducing noise
• CPC Class Codes: F04C 18/126 with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type
• CPC Class Codes: F04C 29/061 Silencers using overlapping frequencies, e.g. Helmholtz resonators
• CPC Class Codes: F04C 29/065 Noise dampening volumes, e.g. muffler chambers

Abstract

The invention comprises a method and apparatus for reducing the noise generated by compressors, including Roots-type blowers. The invention has particular use for reducing noise generated by compressors used in mechanical ventilators, though the advantages thereof may be realized in many different applications. One embodiment of the invention comprises a noise-attenuating gas flow path for a compressor contained in a portable ventilator housing. In one embodiment, the gas flow path comprises a plurality of chambers interconnected by flow tubes. The flow path is folded so as to fit into the limited space of a portable ventilator housing. The dimensions of the chambers and the flow tubes are selected so that an impedance mismatch is created between the chambers and the flow tubes. In one embodiment of the invention, the flow path comprises one or more perforated tubes located in one or more of the chambers. The perforated tube has a port through which gas is accepted and at least one exterior tube through which gas exits. Impedance mismatches are created between the inlet chamber and the exterior tubes and between the exterior tubes and the chamber in which the perforated tube is located, which are useful in attenuating noise. One embodiment of the invention comprises a noise attenuating mounting system for a compressor. The mounting system comprises flexible mounts that cooperate to dampen vibrations generated by the compressor.

Claims

1. A noise attenuating gas flow path for a compressor disposed in an enclosure comprising:

a plurality of interconnected chambers disposed in said enclosure, said chambers interconnected by at least one flow tube, said chambers configured so as to create a plurality of impedance mismatches between said plurality of chambers and said at least one flow tube;

said gas flow path encompassing a majority of an unoccupied volume of said enclosure.

2. The noise attenuating gas flow path of claim 1 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

3. The noise attenuating gas flow path of claim 1 wherein at least one of said chambers is disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

4. The noise attenuating gas flow path of claim 3 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

5. The noise attenuating gas flow path of claim 1 wherein a plurality of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

6. The noise attenuating gas flow path of claim 1 wherein a plurality of said chambers are disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

7. The noise attenuating gas flow path of claim 6 wherein a pluarility of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

8. The noise attenuating gas flow path of claim 1 wherein at least of one said chambers comprises at least one wall integrally formed with a portion of said enclosure.

9. The noise attenuating gas flow path of claim 1 wherein said gas flow path comprises at least one perforated tube disposed in one of said chambers.

10. A noise attenuating gas flow path for a compressor disposed in an enclosure comprising:

a plurality of interconnected chambers integrally formed with said enclosure, said chambers configured so as to create a plurality of impedance mismatches along said flow path;

said gas flow path comprising a noise attenuating inlet gas flow path from an inlet to said enclosure to an inlet of said compressor and a noise attenuating outlet gas flow path from an outlet of said compressor to an outlet of said enclosure.

11. The noise attenuating gas flow path of claim 10 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

12. The noise attenuating gas flow path of claim 10 wherein at least one of said chambers is disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

13. The noise attenuating gas flow path of claim 12 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

14. The noise attenuating gas flow path of claim 10 wherein a plurality of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

15. The noise attenuating gas flow path of claim 10 wherein a plurality of said chambers are disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

16. The noise attenuating gas flow path of claim 15 wherein a pluarility of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

17. The noise attenuating gas flow path of claim 10 wherein at least of one said chambers comprises at least one wall integrally formed with a portion of said enclosure.

18. The noise attenuating gas flow path of claim 10 wherein said gas flow path comprises at least one perforated tube disposed in at least one of said chambers.

19. The noise attenuating gas flow path of claim 10 wherein said gas flow path comprises a plurality of perforated tubes disposed in at least one of said chambers.

29. The noise attenuating gas flow path of claim 10 wherein said gas flow path comprises a plurality of perforated tubes disposed in at least one of said chambers.

20. A noise attenuating gas flow path for a compressor disposed in an enclosure comprising:

a plurality of interconnected chambers disposed in said enclosure, said chambers configured so as to create a plurality of impedance mismatches along said flow path;

said gas flow path encompassing a majority of an unoccupied volume of said enclosure.

21. The noise attenuating gas flow path of claim 20 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

22. The noise attenuating gas flow path of claim 20 wherein at least one of said chambers is disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

23. The noise attenuating gas flow path of claim 22 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

24. The noise attenuating gas flow path of claim 20 wherein a plurality of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

25. The noise attenuating gas flow path of claim 20 wherein a plurality of said chambers are disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

26. The noise attenuating gas flow path of claim 25 wherein a pluarility of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

27. The noise attenuating gas flow path of claim 20 wherein at least of one said chambers comprises at least one wall integrally formed with a portion of said enclosure.

28. The noise attenuating gas flow path of claim 20 wherein said gas flow path comprises at least one perforated tube disposed in at least one of said chambers.

30. A noise attenuating perforated tube for use with a compressor comprising:

an inner chamber comprising a wall;

a plurality of passages traversing said wall, wherein a length of a flow path along a passage is greater than a thickness of said wall.

31. The perforated tube of claim 30 wherein said passages are formed in exterior tubes that project form an exterior surface of said perforated tube.

32. The perforated tube of claim 30 wherein said inner chamber has a circular cross-section.

33. The perforated tube of claim 30 wherein said inner chamber has a rectangular cross-section.

34. The perforated tube of claim 31 wherein said exterior tubes have a circular cross-section.

35. The perforated tube of claim 31 wherein said exterior tubes have a rectangular cross-section.

36. The perforated tube of claim 31 wherein a sum of cross-sectional areas of said passages is greater than a cross-sectional area of said chamber.

37. The perforated tube of claim 31 wherein said exterior tubes are integrally formed with said wall.

38. The perforated tube of claim 37 wherein said wall has an original thickness and wherein said exterior tubes are formed by reducing said wall thickness at locations other than the locations at which siad exterior tubes are located.

39. The perforated tube of claim 31 wherein a first plurality of said exterior tubes have a first length and a second plurality of said exterior tubes have a second length.

40. A mounting system for a compressor in a portable ventilator enclosure comprising:

a plurality of resilient mounts, each of said resilient mounts comprising;

a support member for supporting said resilient mount relative to said compressor;

a resilient damping member connected to said support member;

an opening for receiving a mounting point of a supporting structure;

said mounting system reducing a natural frequency of said compressor when mounted to said resilient mounts from a natural frequency of said compressor when unmounted.

41. The mounting system of claim 40 wherein said support member comprises a threaded fastener.

42. The mounting system of claim 40 wherein said opening comprises a tapered opening formed in said resilient damping member.

43. The mounting system of claim 40 wherein a first plurality of said resilient mounts are disposed between a first side of said compressor and a first supporting structure and a second plurality of said resilient mounts are disposed between a second side of said compressor and a second supporting structure.

44. The mounting system of claim 43 wherein said first and second supporting structures comprise portions of said ventilator enclosure.

45. The mounting system of claim 40 wherein said resilient damping member comprising a foldable wall portion.

46. A mounting system for a compressor in a portable ventilator enclosure comprising:

a plurality of resilient mounts, each of said resilient mounts comprising;

a support member for supporting said resilient mount relative to said compressor;

a resilient damping member connected to said support member, said resilient damping member comprising a foldable wall portion.

47. The mounting system of claim 46 wherein said resilient damping member has a generally circular cross section.

48. The mounting system of claim 46 wherein said foldable wall portion comprises a bellows shaped section.

49. The mounting system of claim 46 wherein said support member comprises a threaded fastener.

50. The mounting system of claim 46 wherein said resilient damping member comprises an opening for receiving a mounting point of a supporting structure.

51. The mounting system of claim 46 wherein said opening comprises a tapered opening formed in said resilient damping member.

52. The mounting system of claim 46 wherein a first plurality of said resilient mounts are disposed between a first side of said compressor and a first supporting structure and a second plurality of said resilient mounts are disposed between a second side of said compressor and a second supporting structure.

53. The mounting system of claim 52 wherein said first and second supporting structures comprise portions of said ventilator enclosure.

54. A noise attenuating system for a compressor disposed in an enclosure comprising:

a flow path comprising a plurality of interconnected chambers configured so as to create a plurality of impedance mismatches along said flow path;

a perforated tube disposed in one of said chambers, said perforated tube comprising an inner chamber comprising a wall and a plurality of passages traversing said wall, wherein a length of a flow path along a passage is greater than a thickness of said wall;

a mounting system comprising a plurality of resilient mounts, said mounting system reducing a natural frequency of said compressor when mounted to said resilient mounts from a natural frequency of said compressor when unmounted.

55. The noise attenuating system of claim 54 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

56. The noise attenuating system of claim 54 wherein at least one of said chambers is disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

57. The noise attenuating system of claim 56 wherein at least one of said chambers is disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

58. The noise attenuating system of claim 54 wherein a plurality of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

59. The noise attenuating system of claim 54 wherein a plurality of said chambers are disposed in an outlet gas flow path from an outlet of said compressor to an outlet from said housing.

60. The noise attenuating system of claim 59 wherein a pluarility of said chambers are disposed in an inlet gas flow path from an inlet to said enclosure to an inlet to said compressor.

61. The noise attenuating system of claim 54 wherein at least of one said chambers comprises at least one wall integrally formed with a portion of said enclosure.

62. The noise attenuating system of claim 54 wherein a plurality of said perforated tubes disposed in at least one of said chambers.

63. The noise attenuating system of claim 54 wherein said passages are formed in exterior tubes that project form an exterior surface of said perforated tube.

64. The noise attenuating system of claim 54 wherein said inner chamber has a circular cross-section.

65. The noise attenuating system of claim of 54 wherein said inner chamber has a rectangular cross-section.

66. The noise attenuating system of claim 63 wherein said exterior tubes have a circular cross-section.

67. The noise attenuating system of claim 63 wherein said exterior tubes have a rectangular cross-section.

68. The noise attenuating system of claim 63 wherein a sum of cross-sectional areas of said passages is greater than a cross-sectional area of said chamber.

69. The noise attenuating system of claim 63 wherein said exterior tubes are integrally formed with said wall.

70. The noise attenuating system of claim 69 wherein said wall has an original thickness and wherein said exterior tubes are formed by reducing said wall thickness at locations other than the locations at which siad exterior tubes are located.

71. The noise attenuating system of claim 63 wherein a first plurality of said exterior tubes have a first length and a second plurality of said exterior tubes have a second length.

72. The noise attenuating system of claim 54 wherein each of said resilient mounts comprises:

a support member for supporting said resilient mount relative to said compressor;

a resilient damping member connected to said support member;

an opening for receiving a mounting point of a supporting structure;

said mounting system reducing a natural frequency of said compressor when mounted to said resilient mounts from a natural frequency of said compressor when unmounted.

73. The noise attenuating system of claim 72 wherein said support member comprises a threaded fastener.

74. The noise attenuating system of claim 72 wherein said opening comprises a tapered opening formed in said resilient damping member.

75. The noise attenuating system of claim 72 wherein a first plurality of said resilient mounts are disposed between a first side of said compressor and a first supporting structure and a second plurality of said resilient mounts are disposed between a second side of said compressor and a second supporting structure.

76. The noise attenuating system of claim 75 wherein said first and second supporting structures comprise portions of said ventilator enclosure.

77. The noise attenuating system of claim 72 wherein said resilient damping member comprising a foldable wall portion.

78. The noise attenuating system of claim 77 wherein said foldable wall portion comprises a bellows shaped section.