HUMIFIER AND LAYERED HEATING ELEMENT

• US 20140131904A1
• Filed: 06/15/2012
• Published: 05/15/2014
• Est. Priority Date: 06/16/2011
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Tang, Zhuo Ran, Huby, Ronald James, Verma, Hargopal, Bath, Andrew Roderick, Foote, Roger Mervyn Lloyd
• Granted Patent: US 9,821,135 B2
• Time in Patent Office: Days
• US Class Current: 261/142
• CPC Class Codes: A61M 16/022 Control means therefor
• CPC Class Codes: A61M 16/1075 by influencing the temperature A61M16/1045 takes precedence
• CPC Class Codes: A61M 16/109 the humidifying liquid or the beneficial agent
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 2205/0211 Ceramics
• CPC Class Codes: A61M 2205/0238 the material being a coating or protective layer
• CPC Class Codes: A61M 2205/025 Materials providing resistance against corrosion
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: B01F 23/20 Mixing gases with liquids
• CPC Class Codes: B01F 23/23 by introducing gases into liquid media, e.g. for producing aerated liquids
• CPC Class Codes: H05B 2203/002 Heaters using a particular layout for the resistive material or resistive elements
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 3/28 heating conductor embedded in insulating material

Abstract

A heating apparatus includes a heating element (48) which converts electrical power to heat energy, a heatable element (44) having a first surface and a second surface, and a dielectric laminate layer (46) between the heating element and the first surface of the heatable element, wherein the dielectric laminate layer (46) is thermally conductive to transfer heat energy from the heating element (48) to the heatable element (44), and wherein the second surface of the heatable element is configured heat a liquid in a container.

Claims

1. A humidifier, comprising:

a tub adapted to hold a liquid; and

a heating apparatus comprising a substrate having a heating track etched thereon.

2. A humidifier according to claim 1, wherein said substrate includes a thermally conductive substrate layer, a copper or alloy or Positive Temperature Coefficient (PTC) layer, and a dielectric laminate layer between the thermally conductive substrate layer and the copper or alloy or PTC layer.

3. A humidifier according to claim 2, wherein the thermally conductive substrate layer is constructed of a metal.

4. A humidifier according to any one of claims 2-3, wherein the dielectric laminate layer is constructed of a ceramic material, a polymeric material, or a ceramic and polymeric mixture material.

5. A humidifier according to any one of claims 2-4, wherein said heating track is etched in the copper or alloy or PTC layer.

6. A humidifier according to claim 5, wherein the heating track is associated with contact pads for electrical leads and at least one electrical component.

7. A humidifier according to any one of claims 5-6, wherein the heating track includes a width in a range of about 0.4 mm to 2 mm.

8. A humidifier according to any one of claims 5-7, wherein a temperature of the heating apparatus is determined by determining a resistance of the heating tracks.

9. A humidifier according to any one of claims 2-8, further comprising a protective layer printed onto at least the copper or alloy or PTC layer.

10. A humidifier according to any one of claims 1-9, wherein the heating apparatus provides a heating surface temperature that can only reach a maximum temperature for a chosen input power.

11. A humidifier according to any one of claims 1-10, wherein the heating apparatus is provided to a humidifier chamber adapted to receive the tub.

12. A humidifier according to any one of claims 1-10, wherein the heating apparatus is integral with the tub.

13. A humidifier, comprising:

a tub adapted to hold a liquid; and

a heating apparatus including a metallic hot plate, a heating element with copper or alloy or PTC heating tracks to provide heat to heat the liquid, a thermally conductive laminate layer constructed of a ceramic or polymeric material between the hot plate and the heating element, and a printed protective layer to cover at least the heating tracks.

14. A humidifier, comprising:

a tub adapted to hold a liquid; and

a heating apparatus including a hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer to cover at least the heating element,

wherein the heating element includes a copper or alloy or PTC layer with heating tracks to provide heat to heat the liquid.

15. A humidifier according to claim 14, wherein the heating tracks are etched in the copper or alloy or PTC layer of the heating apparatus.

16. A humidifier according to any one of claims 14-15, wherein the heating tracks are associated with contact pads for electrical leads or spring contacts and at least one electrical component.

17. A humidifier according to any one of claims 14-16, wherein the heating tracks include a width in a range of about 0.3 mm to 2 mm.

18. A humidifier according to any one of claims 14-17, wherein a temperature of the heating apparatus is determined by determining a resistance of the heating tracks.

19. A humidifier according to any one of claims 14-18, wherein the hot plate is formed of a metal or metal alloy including at least one of aluminium, stainless steel and copper.

20. A humidifier, comprising:

a tub adapted to hold a liquid; and

a heating apparatus including a hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer to cover at least the heating element,

wherein the protective layer is printed onto at least the heating element.

21. A humidifier according to claim 20, wherein the laminate layer is a dielectric laminate layer constructed of a ceramic, polymeric or polymeric mixture material.

22. A humidifier according to any one of claims 20-21, wherein the protective layer is printed onto the laminate layer.

23. A humidifier according to claim 22, wherein the protective layer extends over peripheral edges of the heating element and onto portions of the laminate layer.

24. A humidifier according to any one of claims 20-23, wherein the protective layer includes a solder mask.

25. A humidifier according to any one of claims 20-24, wherein the thermally conductive laminate layer includes a thickness in a range of about 20-160 μ

m.

26. A humidifier according to any one of claims 20-25, wherein the hot plate is formed of a metal or metal alloy including aluminium, stainless steel or copper.

27. A humidifier according to any one of claims 20-26, wherein contact pads and/or other conductive portions of the heating element are exposed through the protective layer.

28. A process of making a heating apparatus for a humidifier including a tub to hold a liquid, comprising:

providing a substrate having a first side adapted to be in thermal contact with the liquid and a second side;

etching heating tracks in the second side of the substrate; and

applying a protective layer to the second side of the substrate to at least cover the heating tracks.

29. A process according to claim 28, wherein providing a substrate includes providing a substrate including a metallic layer providing the first side, a copper, alloy or PTC layer providing the second side, and a dielectric layer between the metallic layer and the copper, alloy or PTC layer.

30. A process according to any one of claims 28-29, wherein applying a protective layer includes printing the protective layer to the second side of the substrate.

31. A process according to any one of claims 28-30, wherein applying a protective layer includes exposing contact pads and/or other conductive portions associated with the heating tracks through the protective layer.

32. A heating apparatus including:

a heating element which converts electrical power to heat energy;

a heatable element having a first surface and a second surface; and

a dielectric laminate layer between the heating element and the first surface of the heatable element, wherein the dielectric laminate layer is thermally conductive to transfer heat energy from the heating element to the heatable element, and wherein the second surface of the heatable element is configured to heat a liquid in a container.

33. The heating apparatus of claim 32, further comprising a protective layer covering an outer surface of the heating element and an outer surface of the dielectric laminate layer.

34. The heating apparatus of claim 33, wherein the protective layer extends over peripheral edges of the heating element and dielectric laminate layer, and onto a peripheral portion of the first surface of the heatable element extending beyond the heating element and dielectric laminate layer.

35. The heating apparatus of any of claims 32 to 34, wherein the dielectric laminate layer is a thin layer comprising at least one of polytetrafluoroethylene, e.g., Teflon®

, polyimides, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composite, and reinforced fiberglass.

36. The heating apparatus of any of claims 32 to 35, wherein a thickness of the dielectric laminate layer is in a range of 20 um to 160 um.

37. The heating apparatus of any of claims 32 to 36, wherein a dielectric breakdown voltage of the dielectric laminate layer is above 2 kV.

38. The heating apparatus of any of claims 32 to 37, wherein the heatable element includes a conductive metallic plate, and the first and second surfaces are opposing surfaces of the plate.

39. The heating apparatus of any of claims 32 to 38, wherein the heating element includes conductive metallic foils arranged in a serpentine pattern on the dielectric laminate layer.

40. The heating apparatus of any of claims 32 to 39, wherein the heating element is a metallic printed circuit board (PCB) and the heating element includes tracks of conductive metallic foils arranged on the PCB.

41. The heating apparatus of any of claims 32 to 40, wherein a thickness of the apparatus is no greater than 1.5 mm.

42. The heating apparatus of any of claims 32 to 41, wherein the second surface is flat.

53. A humidifier including a container for retaining a volume of liquid and a heating apparatus as claimed in any of claims 32 to 52, wherein the heating apparatus is in thermal contact with the liquid to deliver a heat to the liquid and effect a vaporization of the liquid into an airstream.

43. A printed circuit board heater including:

a heating element track;

a thermally conductive dielectric layer; and

a thermally conductive board having a first surface adapted to transfer heat into a container and a second surface, opposite to the first surface, on which the thermally conductive dielectric layer is sandwiched between said board and said heating element track;

wherein an electrical current terminal to the heating track provides for the application of electrical energy to the heating element track which causes resistance heating of the heating track, and wherein heat energy from the heating element track transfers through the thermally conductive dielectric layer to the board which transfers the heat energy to the container.

44. The printed circuit board heater of claim 43, wherein the printed circuit board heater is integral with a surface of the container.

45. The printed circuit board heater of claim 44, wherein the first surface is shaped to receive a bottom surface of the container.

46. The printed circuit board heater of any of claims 43 to 45, further comprising a protective layer covering the heating element track layer and the dielectric layer.

47. The printed circuit board heater of claim 46, wherein the protective layer extends over peripheral edges of the heating element track and dielectric layer, and onto a peripheral portion of the first surface of said board extending beyond the heating element track and the dielectric layer.

48. The printed circuit board heater of any of claims 43 to 47, wherein the thermally conductive dielectric layer is a thin layer comprising at least one of polytetrafluoroethylene, e.g., Teflon®

, polyimides, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composite, and reinforced fiberglass.

49. The printed circuit board heater of any of claims 43 to 48, wherein a thickness of the thermally conductive dielectric layer is in a range of 20 um to 160 um.

50. The printed circuit board heater of any of claims 43 to 49, wherein a dielectric breakdown voltage of the thermally conductive dielectric layer is above 2 kV.

51. The printed circuit board heater of any of claims 43 to 50, wherein the thermally conductive board is formed of a metal or metal alloy plate including an aluminum, stainless steel or copper plate.

52. The printed circuit board heater of any of claims 43 to 51, wherein the heating element track layer includes conductive metallic foils arranged in a serpentine pattern on the dielectric layer.

54. A method to form a heating apparatus comprising:

providing a substrate having a first surface adapted to heat a liquid in a container;

applying a thermally conductive dielectric layer to a second surface of the substrate, wherein the second surface is opposite to the first surface; and

applying a heating element layer to the thermally conductive dielectric layer such that the thermally conductive dielectric layer is sandwiched between the second surface of the substrate and the heating element layer.

55. The method of claim 54, further comprising applying a protective layer to the heating element layer and the thermally conductive dielectric layer.

56. The method of claim 54 or 55, wherein the substrate is a metal plate and the method is performed using metal core printed circuit board processing.

57. The method of any of claims 54 to 56, wherein the heating element layer is applied as a serpentine track of conductive foil on the thermally conductive dielectric layer.

58. The method of any of claims 54 to 57, wherein the thermally conductive dielectric layer is applied as a composite layer of dielectric particles and a resin.

59. The method of any of claims 54 to 58, further comprising integrating the formed heating plate into a bottom of a liquid container.

60. The method of any of claims 54 to 59, further comprising printing the heating element layer as a serpentine pattern on the thermally conductive dielectric layer.

61. A humidifier, comprising:

a tub adapted to hold a liquid;

a heating apparatus including a heating element having a first side and a second side, the heating element including heating tracks;

a first thermally conductive laminate layer provided on the first side of the heating element; and

a second thermally conductive laminate layer provided on the second side of the heating element.

62. The humidifier according to claim 61, wherein a substrate is provided to an end portion of the heating element to form a connector section.

63. The humidifier according to claim 62, wherein the end portion of the heating element forms an electrical contact to receive electrical power.

64. A humidifier, comprising:

a tub having an inner portion adapted to hold a liquid;

a heating apparatus including a hot plate and a heating element provided to a first side of the hot plate; and

an overmold formed on the inner portion of the tub and completely surrounding the heating apparatus such that the heating apparatus is embedded within the overmold.

65. The humidifier according to claim 64, wherein the overmold comprises thermally conductive plastic.

66. The humidifier according to any one of claims 64 and 65, wherein the tub includes sidewalls and the overmold includes sidewall portions formed on the tub sidewalls.

67. The humidifier according to any one of claims 64-66, wherein the hot plate is formed of a thermally conductive material including a metal, a metal alloy, aluminium, stainless steel, copper or a thermally conductive plastic.

68. A humidifier, comprising:

a tub having an inner portion adapted to hold a liquid;

a heating apparatus including a support substrate and a heating element provided to a first side of the support substrate, the support substrate being distal to the inner portion of the tub and the heating element being proximal to the inner portion of the tub; and

a first thermally conductive protective layer provided to the heating element.

69. The humidifier according to claim 68, wherein the first protective layer is overmolded over the heating element.

70. The humidifier according to any one of claims 68 and 69, wherein the support substrate comprises at least one of a composite epoxy material (CEM) and a fiberglass reinforced epoxy laminate.

71. The humidifier according to any one of claims 68-70, wherein the first protective layer comprises stainless steel.

72. The humidifier according to any one of claims 68-71, further comprising an electrical insulating layer between the first protective layer and the heating element.

73. The humidifier according to any one of claims 68-72, further comprising a second thermally conductive protective layer provided to a second side of the support substrate and an edge portion of the support substrate.

74. The humidifier according to any one of claims 68-73, wherein an end portion of the heating element is exposed from the first protective layer to provide an electrical contact to receive electrical power.

75. The humidifier according to any one of claims 68-74, wherein the heating element comprises polymer thick film (PTF).