humidifier

Abstract

To solve the problem in which known heating assemblies may be suitable for its intended purpose, but require complex, costly, and manually intensive manufacturing processes.SOLUTION: 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, where the dielectric laminate layer (46) is thermally conductive to transfer heat energy from the heating element (48) to the heatable element (44), and where the second surface of the heatable element is configured to heat a liquid in a container.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] Cross-reference to application This application claims the benefit of Australian Provisional Application No. 2011902350, filed June 16, 2011, and U.S. Provisional Application No. 61 / 628,622, filed November 3, 2011. Each of the above-mentioned applications is incorporated herein by reference in its entirety.

[0002] The present technology relates to electric heaters, particularly heaters used to heat fluids in containers. More particularly, the present technology relates to electric heaters used in humidification, such as humidification of breathable gases, devices including such electric heaters, and methods of using such electric heaters. The electric heaters can be used in a range of devices including all types of respiratory ventilation systems, including invasive and non-invasive ventilation, continuous positive airway pressure (CPAP), and bi-level therapy and treatment for sleep disordered breathing (SDB) conditions, such as obstructive sleep apnea (OSA), and for various other respiratory disorders and diseases. [Background technology]

[0003] Respirators generally have the ability to modify the humidity of breathable gas to reduce drying of the patient's airway and the resulting patient discomfort and associated complications. The use of a humidifier placed between the flow generator and the patient's mask produces humidified gas that minimizes drying of the nasal mucosa and improves patient airway comfort. In colder climates, warm air applied generally to the facial area in and around the mask may be more comfortable than applying cool air.

[0004] Many humidifier types are available, including those that are integrated with or configured to be coupled to an associated respirator. Passive, unheated humidifiers can be somewhat comfortable, but heated humidifiers generally provide more moisture and temperature to the air, increasing patient comfort. Heated humidifiers typically include a water tub with a capacity to hold several hundred milliliters of water, a heating assembly for heating the water in the tub, a control system that allows the level of humidification to be varied, a gas inlet port that accepts gas from a flow generator, and a gas outlet port that is adapted to be connected to a patient conduit that delivers humidified pressurized gas to a patient mask.

[0005] While known heating assemblies may be adequate for their intended purposes, they require complex, costly and manually intensive manufacturing processes.

[0004] U.S. Patent No. 5,393,636 describes an exemplary electric heating plate structure. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 6,660,977 Summary of the Invention [Problem to be solved by the invention]

[0007] One aspect of the present technology relates to a heated humidifier for use in a respiratory therapy device.

[0008] Another aspect of the present technology relates to a heating apparatus or heating assembly for a respiratory therapy device, which includes a heating element and a hot plate. The heating element and the hot plate are separated by a separation element, which has high thermal conductivity and high electrical insulation, e.g., low electrical conductivity. In an example, the separation element has a predetermined format, e.g., a suitable substrate, suitable for printing onto the heating element. The hot plate is capable of heating water in a container contained within the respiratory therapy device.

[0009] Another aspect of the present technology relates to a heating apparatus for a respiratory therapy device, the heating apparatus including a heating element and a hot plate, the heating element and the hot plate being spaced apart by a layer that electrically insulates the heating element and the hot plate, and the heating apparatus enabling heat transfer between the heating element and the hot plate.

[0010] In an example, the heating device includes a stack of (i) a thermally conductive material, e.g., a hot plate, a metal plate, a thermally conductive substrate layer, (ii) a thermally conductive dielectric laminate layer, (iii) a heating element, and (iv) a protective layer. The dielectric laminate layer provides electrical insulation between the heating element and the hot plate, e.g., to avoid electrical shorts between the currents flowing through the heating element and the hot plate. The heating element can be printed on or otherwise applied to the laminate layer by conventional printing techniques used in printed circuit board (PCB) manufacturing and assembly. Alternatively, the heating element can be applied to the laminate layer as a sheet, with a portion of the sheet being etched to form the tracks of the heating element. The heating element can be a narrow strip of conductive material (e.g., copper foil) arranged in a serpentine pattern. The thickness of the heating element and the arrangement of the serpentine pattern can be selected based on various design considerations, such as the shape of the bottom of the humidifier tab and the amount of heat energy to be transferred to the humidifier tab.

[0011] Another aspect of the present technology relates to a heating apparatus including a heating element that converts electrical power into thermal 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, the dielectric laminate layer being thermally conductive to transfer thermal energy from the heating element to the heatable element, and the second surface of the heatable element configured to heat a liquid in a container.

[0012] In an example, the protective layer can cover an outer surface of the heating element and an outer surface of the dielectric laminate layer. The protective layer can extend over a peripheral edge of the heating element and the dielectric laminate layer, and can extend over a peripheral portion of the first surface of the heatable element that extends beyond the heating element and the dielectric laminate layer.

[0013] In an example, the dielectric laminate layer can be a thin layer including at least one of polytetrafluoroethylene, such as Teflon®, polyimide, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composites, and fiberglass reinforcement. The thickness of the dielectric laminate layer can range from about 20 μm to 160 μm, such as 60-120 μm. The dielectric substrate can be suitable to withstand a voltage of greater than about 2 kV. The heatable element can include a conductive metallic plate, the first and second surfaces being opposing surfaces of the plate. The heatable element can be a metallic printed circuit board (PCB), and the heating element can include a conductive metallic foil track disposed on the PCB.

[0014] In an example, the heating element can include a conductive metal foil, e.g., copper foil, disposed in a serpentine pattern on the dielectric laminate layer. The heating element can have a direct current (DC) resistance at room temperature in the range of about 5 ohms to 25 ohms, e.g., 5-15 ohms. The thickness of each track of the heating element can be in the range of about 0.4 mm to 1 mm, for example.

[0015] Another aspect of the present technology relates to a printed circuit board heater including a heating element track layer, a thermally conductive dielectric layer, and a substrate board having a first surface adapted to transfer heat into the vessel and a second surface, the second surface being opposite the first surface, on which the thermally conductive dielectric layer is sandwiched between the board and the track layer, electrical current terminals are provided on the track layer to allow application of electrical energy to the heating element track layer causing resistive heating of the track layer, thermal energy from the track layer is transferred through the thermally conductive dielectric layer to the substrate board, which transfers the thermal energy to the vessel. The substrate board can include a metal board or other printed circuit type board, for example forming a thermally conductive board.

[0016] Another aspect of the present technology relates to a method of forming a heating device, the method including the steps of providing a metal plate having a first surface adapted to heat a liquid in a container, applying a thermally conductive dielectric layer to a second surface of the metal plate, the second surface being opposite 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 metal plate and the heating element layer.

[0017] Another aspect of the present technology relates to a humidifier including a tub adapted to hold a volume of liquid and a heating device including a PCB type substrate. In an example, the substrate may include a metal layer, a copper layer, and a dielectric laminate layer between the metal layer and the copper layer. The metal layer may be comprised of aluminum, stainless steel, other thermally conductive metals, or other types of PCB substrates. The dielectric laminate layer may be comprised of a ceramic or polymeric material. Heating tracks may be etched into the copper or heating alloy layer. A protective layer may be printed on at least the copper layer.

[0018] In an example, the heating device is provided in a humidifier chamber adapted to receive the tub, hi another example, the heating device is integral with the tub.

[0019] Another aspect of the present technology relates to a humidifier including a tub adapted to hold a liquid and a heating device, the heating device including a metallic hot plate, a heating element comprising a copper, heating alloy, or positive temperature coefficient (PTC) heating track (e.g., the heating track can be etched or otherwise provided in a layer of copper, heating alloy, or PTC material, e.g., forming a PTC layer), or a combination thereof, for providing heat to heat the liquid, a thermally conductive laminate layer, e.g., composed of a ceramic material, a polymer material, or a composite material of ceramic and polymer, between the hot plate and the heating element, and a printed protective layer for covering at least the heating track.

[0020] Another aspect of the present technology relates to a humidifier, the humidifier including a tub adapted to hold a liquid, and a heating device including a thermally conductive hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer for covering at least the heating element. The heating element can include a copper or alloy or PTC heating track, or a combination thereof, and can provide heat to heat the liquid.

[0021] Another aspect of the present technology relates to a humidifier including a tub adapted to hold a liquid and a heating device including a thermally conductive hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer for covering at least the heating element, the laminate layer being a dielectric laminate layer comprised of a ceramic material, or a polymer material, or a polymer blend material.

[0022] Another aspect of the present technology relates to a humidifier including a tub adapted to hold a liquid and a heating device including a thermally conductive hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer for covering at least the heating element, the protective layer being printed, spread or molded onto at least the heating element.

[0023] Another aspect of the present technology relates to a process for making a heating device for a humidifier that includes a tub for holding a liquid, the process including the steps of providing a substrate having a first side adapted for thermal contact with the liquid and a second side, etching a heating track on the second side of the substrate, and applying a protective layer to the second side of the substrate to at least cover the heating track.

[0024] Another aspect of the present technology relates to a humidifier including a tub adapted to hold a liquid and a heating device, the heating device including a heating element having a first side and a second side, the heating element including a heating track, a first thermally conductive laminate layer disposed on the first side of the heating element, and a second thermally conductive laminate layer disposed on the second side of the heating element.

[0025] Another aspect of the present technology relates to a humidifier that includes a tub having an inner portion adapted to hold a liquid, a heating device including a thermally conductive hot plate and a heating element disposed on a first side of the hot plate, and an overmold formed on the inner portion of the tub, the overmold completely surrounding the heating device such that the heating device is embedded within the overmold. The thermally conductive hot plate can be formed from a metallic material such as aluminum, stainless steel, or other thermally conductive metal, or a thermally conductive plastic.

[0026] Another aspect of the present technology relates to a humidifier including a tub having an inner portion adapted to hold a liquid and a heating device, the heating device including a support substrate and a heating element disposed on a first side of the support substrate, the support substrate distal to the inner portion of the tub and the heating element proximal to the inner portion of the tub, and a first thermally conductive protective layer disposed on the heating element.

[0027] Other aspects, features, and advantages of the present technology will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which are a part of this disclosure and illustrate, by way of example, the principles of the present technology.

[0028] The accompanying drawings facilitate an understanding of various examples of the present technology. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view of a respiratory ventilator including a flow generator and a humidifier in accordance with an example of the present technology. [Figure 2A] 2 is an upright perspective view of a humidifier tub of the humidifier shown in FIG. 1 in accordance with an example of the present technology. [Figure 2B] FIG. 2 is an inverted perspective view of a humidifier tab of the humidifier shown in FIG. 1 in accordance with an example of the present technology. [Diagram 3] FIG. 2 is an exploded view of a humidifier chamber of the humidifier shown in FIG. 1 in accordance with an example of the present technology. [Figure 4-1] FIG. 4 is a schematic cross-sectional view of a heating device for the humidifier chamber shown in FIG. 3 in accordance with an example of the present technology. [Figure 4-2] FIG. 4 is a schematic cross-sectional view of a heating device for the humidifier chamber shown in FIG. 3 in accordance with an example of the present technology. [Diagram 5] FIG. 4-1 is a schematic diagram of a circuit layout of the heating device shown in FIGS. 3 and 4-1 in accordance with an example of the present technology. [Figure 6] 1 is a schematic cross-sectional view of a humidifier tub including a heating device in accordance with an example of the present technology; [Figure 7]2 is a schematic diagram of a circuit layout of a heating device according to an example of the present technology; [Figure 8-1] 1 is a schematic diagram of a heating device and electrical contact structure in accordance with an example of the present technology; [Figure 8-1A] FIG. 8-2 is an enlarged view of a portion of the heating device and electrical contact structure shown in FIG. 8-1. [Figure 9-1] 1 is a schematic diagram of a heating device and electrical contact structure in accordance with an example of the present technology; [Figure 9-2] 1 is a schematic diagram of a heating device and electrical contact structure in accordance with an example of the present technology; [Figure 10] FIG. 8-2 is a schematic plan view of the heating device and electrical contact structure shown in FIG. 8-1. [Figure 11] 1 is a schematic cross-sectional view of a humidifier tab in accordance with an example of the present technology; [Figure 12-1] 1 is a schematic cross-sectional view of a humidifier tab in accordance with an example of the present technology; [Figure 12-2] 1 is a schematic cross-sectional view of a humidifier tab in accordance with an example of the present technology; [Figure 13] 1 is a schematic cross-sectional view of a humidifier tub including a heating device in accordance with an example of the present technology; [Figure 14A] 1 is a schematic diagram of a heating device and electrical contact structure in accordance with an example of the present technology; [Figure 14B] 1 is a schematic diagram of a heating device and electrical contact structure in accordance with an example of the present technology; [Figure 15-1] 1 is a schematic cross-sectional view of a humidifier tab in accordance with an example of the present technology; [Figure 15-2] 1 is a schematic cross-sectional view of a humidifier tab in accordance with an example of the present technology; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The following description is provided in the context of several examples (most of which are illustrated and some of which may not be illustrated) that may have common characteristics and features. It should be understood that one or more features of any one example may be combinable with one or more features of the other examples. In addition, any single feature or combination of features in any one or more examples may constitute patentable subject matter.

[0031] As used herein, the word "comprising" is to be understood in its "open" sense, i.e., the meaning of "including," and therefore not limited to its "closed" sense, i.e., the meaning of "consisting only of." Corresponding meanings are to be attributed to the corresponding words "comprise," "comprised," and "comprises" where they occur.

[0032] The term "air" is meant to be considered to include breathable gases, for example air with supplemental oxygen.

[0033] respiratory system FIG. 1 shows a respirator 10 including a flow generator 12 and a humidifier 14. The humidifier 14 includes a humidifier chamber 16 and a lid 18 for the chamber. The lid is movable, e.g., pivotable between an open position and a closed position. A water chamber, or humidifier tub 20, is seated or otherwise disposed within the humidifier chamber 16 and is covered by the lid 18 when the lid is in the closed position. In another example, the humidifier chamber can have a fixed lid rather than a movable / pivotable lid. In another example, the humidifier chamber can have no lid.

[0034] The tub 20 is constructed and arranged to hold a liquid, such as water, used to add moisture to the breathable gas. The tub 20 includes a tub lid 22 configured to direct the flow of breathable gas (air stream) generated by the flow generator 12 along a channel 24 and through an outlet 26 of the channel 24 that directs the gas into the tub 20. The tub 20 includes a gas outlet 28 for the flow of humidified breathable gas. The gas outlet 28 is connectable to a tube (not shown) that is configured to deliver the humidified gas flow to a patient interface, e.g., a mask. The tub can have different configurations, e.g., have inlets and / or outlets at different locations.

[0035] 2A and 2B show an exemplary humidifier tub 20 that is separate from the humidifier chamber 16. The tub is removable from the humidifier chamber 16 to allow the tub to be filled with water or to be washed. The tub lid 22 connects to a tub bottom or bottom container 30, and the lid 22 and the tub bottom 30 combine to form the tub 20. When the tub 20 is installed in the humidifier chamber 16, the tub bottom 30 is in thermal contact with a heating device or heating assembly 36 of the humidifier chamber 16, shown in FIG. 3. The tub bottom 30 comprises a thermally conductive material, such as, for example, a metallic material such as aluminum, copper, brass, or stainless steel, or any other alloy or suitable material with thermal conductivity for conducting heat received from the heating device 36 to the liquid contained inside the tub 20. In an example, the tub bottom is formed entirely from metal. Alternatively, the tub bottom can have a bottom plate 32 formed from a thermally conductive material while the remainder of the tub is formed from another material, e.g., a plastic material. Alternatively, the tub bottom and the heating device can be integral, e.g., the bottom plate and the heating device can be integral. That is, the heating device can form the tub bottom and directly heat the liquid contained inside the tub. Although in FIG. 3 the heating device is shown as being planar and at the bottom of the chamber 16, the heating device can have other forms and be at other locations relative to the chamber and the tub. In another example, the heating device can be located in other areas, such as on the sidewalls of the tub, and directly contact the liquid to be heated. In another example, the heating device can be shaped to fit the sidewalls 34 of the humidifier chamber 16 such that the heating device abuts against a metal portion of the sidewalls of the tub. In another example, a heating device can be mounted within the tub and elevated from the tub bottom 30 such that water is provided over the top and bottom surfaces of the heating device. The tub designs, shapes, and configurations described herein are exemplary and other tubs and liquid containers may be suitable for the present technology.

[0036] As shown in FIG. 3, a cradle bottom 40 is provided below the heating device 36, and an insulating layer 38 is provided between the heating device 36 and the cradle bottom 40. The cradle bottom 40 can be a bottom plate that is releasable to the humidifier chamber 16. The cradle bottom 40 can include a flat surface 41 structured to form a seat for the insulating layer 38 and the heating device 36. The insulating layer 38 can be separable from the cradle bottom and the heating device, or can be bonded to the cradle bottom and / or the heating device. The insulating layer is structured to prevent excessive heat transfer to the cradle bottom 40 and avoid scalding anyone touching the bottom cradle or damaging furniture on which the humidifier chamber is seated. In an alternative example, the insulating layer 38 can not be provided, since heat transfer from the heating device 36 to the tub bottom 30 can be substantially effective and heat dissipation towards the cradle bottom 40 can be insignificant.

[0037] Electrical leads 42 connect to the heating device 36 and provide power to the electrical components of the heating device 36. The electrical leads 42 may extend to electrical connections within or outside the humidifier chamber 16. The electrical leads may connect the heating device to a controller 43, which may be connectable to a power source such as an electrical wall outlet. The controller may regulate the voltage or current applied to the heating device. In examples, the controller may provide one or more of the following: a power switch, temperature detection, fault detection (e.g., open circuit to PCB, CPU, power device, power switch, short circuit, overheating, poor connection, sensor, water ingress), fault protection, and / or an electrical interface to the heater.

[0038] heating device 4 and 5 show a heating device or heating assembly 36 according to an example of the present technology. As shown, the heating device 36 includes a hot plate 44 (also referred to as a heatable element, metal board, or substrate), a thermally conductive laminate layer 46, a heating element 48, a protective layer 50, at least one electrical component 52 (temperature sensing and / or protection), and electrical leads 42 that supply electricity to the heating element 48 and the at least one electrical component 52.

[0039] As described below, heating devices according to examples of the present technology provide assemblies that are easier to process, more efficient, more reliable, and less costly.

[0040] Hot plate The hot plate 44 comprises a thermally conductive material such as aluminum (e.g., anodized aluminum), stainless steel, copper, or any other suitable metal or metal alloy, forming, for example, a metal alloy plate, such as an aluminum plate, a stainless steel plate, or a copper plate. A metallic hot plate can have a surface treatment, such as anodized to form a protective oxide layer that is corrosion resistant. The hot plate can be thin, such as having a thickness ranging from about 0.6 mm to 1.6 mm, e.g., 1.0 mm to 1.5 mm. In an example, the hot plate can constitute a significant percentage of the overall thickness of the heating device. For example, the heating device can include a hot plate, a thermally conductive laminate layer, a heating element, and a protective layer, and the heating device can be similarly thin, having a thickness ranging from about 0.5 mm to 1.7 mm, e.g., 1.1 mm to 1.6 mm, with all but about 0.1 mm to 0.2 mm of the heating device thickness being attributable to the hot plate. In alternative examples, the hotplate can be formed from other suitable materials, such as thermally conductive non-metallic materials, such as ceramic materials and thermally conductive plastics.

[0041] Thermally conductive laminate layer The thermally conductive laminate layer 46 can be a coating, layer, or board that is bonded to the hot plate. The thermally conductive laminate layer 46 can include a material that has good thermal conductivity properties but low electrical conductance (e.g., relatively high electrical resistance), and thus can be referred to as a dielectric laminate layer. The thermally conductive laminate layer can be a composite layer of dielectric particles embedded in a filler material, such as a resin. For example, the laminate layer 46 can include electrically insulating dielectric materials, such as ceramics, polymers, polymers and ceramics, polymers mixed with inorganic particles, polytetrafluoroethylene, such as Teflon®, polyimides, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composites, and ceramics coated with reinforced glass fibers, arranged to form an electrically insulating layer. In an example, the dielectric breakdown voltage of the laminate layer can be greater than 2 kV. Additionally, the laminate layer 46 can be rigid or flexible and can be planar or have some other shape that can conform to the bottom and / or sides of the tab.

[0042] The thermally conductive laminate layer 46 provides electrical insulation between the heating element 48 and the hot plate 44. The thermally conductive laminate layer is also an efficient conductor of heat generated by the heating element 48, transferring the heat to the hot plate 44. The heat generated by the heating element 48 flows efficiently through the thermally conductive laminate layer and through the hot plate 44 to the tub and to the water contained therein. Thus, the heat generated by the heating element 48 is drawn away, or dissipated, from the heating element 48 and transferred towards the hot plate 44. That is, the high thermal conductivity of the laminate layer 46 and the hot plate 44 provides an effective thermal conductivity gradient that allows heat to flow efficiently from the heating element 48, through the laminate layer 46, the hot plate 44, and to the tub 20. Hot plate 44 acts as a heat sink, drawing off thermal energy generated in heating element 48 and distributing the energy to heat the water in the tub. Heat is collected and stored in hot plate 44 for use in heating tub bottom 30. Thermally conductive tub bottom 30 is in thermal contact with hot plate 44 and receives the heat and uses it to heat the liquid contained inside tub 20, thereby adding humidity to the pressurized gas (e.g., 4-20 cmH2O) passing through the tub.

[0043] In an example, the laminate layer 46 has a dielectric thermal conductivity in the range of 0.5 to 4 watts per meter Kelvin (W / mk), e.g., in the range of about 0.5 to 1.00 or more. The laminate layer can be a thin layer, e.g., 20 micrometers (μm) to 160 μm, e.g., 60-120 μm. The thinness of the laminate layer contributes to minimal resistance to heat transfer through the laminate layer.

[0044] In an example, the heating device may not include a separate hot plate 44. Rather, the thermally conductive laminate layer 46 itself may form the heating surface. This configuration may provide a flexible circuit arrangement. In an example, the heating element 48 may be disposed between two layers 57, 58 of thermally conductive laminate material (e.g., flexible polyimide film such as Kapton®) as shown in FIG. 4-2. One or more thermally conductive substrates, pads, pins, or contacts 61, such as metal substrates, pads, contacts, or pins (e.g., made from aluminum, stainless steel, copper, etc.), may be bonded to a portion (e.g., edge portion) of the heating element 48 to form a connection 59. An exposed portion of the heating element 48 adjacent to the substrate 61 may form an electrical contact 63 and accept electrical power. The connection 59 may be formed prior to forming a protective layer (as described below) that is additionally overmolded on top of the heating element 48. The arrangement of connections 59 provides a matrix connector that allows direct electrical and / or thermal contact to heating elements 48 so that additional functions can be performed (e.g., temperature sensing of the heating elements).

[0045] Heating elements The heating elements 48 can be formed from electrical resistance heating materials such as copper, electrical heating alloys such as iron-nickel alloys, copper-nickel alloys, iron-chromium-aluminum alloys, nickel-chromium alloys, and the like, as well as other materials such as PTC ink materials, carbon ink materials, copper foils, and other materials having relatively low electrical resistance, or combinations thereof. The heating elements 48 can include metallic foils, tracks, or strips arranged in a serpentine pattern, such as rows (see, for example, FIG. 5). It is noted that each line of the heating elements 48 in FIG. 5 represents a "track." The heating elements 48 can be printed or applied to the thermally conductive laminate layer 46, as shown in FIG. 5. The layout of the heating elements and the shape of the serpentine pattern can depend on the shape of the bottom plate 32 of the tub. In use, the heating elements convert electrical power into thermal energy.

[0046] In an example, the tracks of the heating elements 48 can be uniformly distributed across the laminate layer to provide a uniform heating profile to the hot plate 44. For a target heating performance, the track design of the heating elements depends on a number of factors. For example, the resistivity of the heating element material affects the track layout design and the track coverage of the laminate layer 46 and the hot plate 44. In another example, the heating alloy is a better electrical resistance heater material compared to copper. Therefore, to achieve a similar heating profile, the copper heating track can be smaller in width (e.g., in the range of about 0.3 mm to 2 mm, e.g., 0.4 mm to 1 mm) and longer in length compared to the heating alloy or aluminum heating track. In such a configuration, a larger range of the heating device can be covered to achieve a similar desired heating profile. Those skilled in the art will understand that other track configurations can be provided to generate different heating profiles.

[0047] 7 shows a heating element 248 including an alternative example of a track layout or pattern. As shown, the tracks or strips are arranged in a concentric ring-like fashion. Advantages of this layout include improved thermal distribution and improved tolerance for thermal expansion / contraction of the tracks as they are heated / cooled. This layout also improves resistance accuracy during the heating process.

[0048] protective layer The protective layer 50 may include a material commonly used as a "solder mask," such as, for example, a polymer or acrylic. Solder masks are conventionally printed or otherwise applied to coat printed circuit boards (PCBs), thermally conductive laminate layers, and conductive traces of heating elements during the PCB and metal-core printed circuit board (MCPCB) manufacturing process. In the context of a heating device, the protective layer may be printed or otherwise applied to coat the heating element 48 and the thermally conductive laminate layer 46. The heating element is sandwiched between the protective layer 50 and the thermally conductive laminate layer 46. The protective layer 50 may extend beyond the peripheral edge of the heating element 48 and directly coat portions of the thermally conductive laminate layer 46 (see, for example, the right edge of the device shown in FIG. 4-1).

[0049] Exemplary materials for the protective layer 50 include, for example, a screen printable epoxy mask, a liquid photosensitive solder mask (IPSM), and a dry film photosensitive solder mask (DFSM). The protective layer 50 seals the heating device 36, prevents leakage currents, and protects the laminate layer 46 and the heating element 48 against environmental factors such as corrosion and physical scratching. The protective layer 50 can be printed or otherwise applied as a direct coating to the surfaces of the hot plate 44 that are not covered by the laminate layer. The protective layer 50 can also provide electrical insulation and some thermal insulation between the heating element 48 and the insulating layer 38 of the cradle bottom 40 of the humidifier chamber 16.

[0050] A protective layer 50, such as a solder mask, can be applied over the laminate layer 46 and the heating elements 48 by screen printing, by well-known mask printing techniques, or as a sheet that is adhesively bonded to the heating elements and laminate layer. Additionally, a stencil can be positioned over specific locations on the heating elements and laminate layer such that the contact pads, and possibly other locations, are not coated with the protective layer. After the protective layer is printed, applied, or otherwise bonded to the heating elements and laminate layer, the stencil can be removed to expose the contact pads and other locations that will be exposed.

[0051] The contact pads and / or other conductive portions of the heating element can be exposed through the protective layer 50 to allow connection of electrical leads to the heating element, for example by surface mount technology. These openings in the protective layer for the contact pads can be applied automatically during an automated printing or coating process.

[0052] Electrical Leads The electrical leads 42 provide a conductive path for electrical power from a power source to be applied to the heating element 48. The electrical leads can be connected to wires that are compatible with a power source, such as a transformer or inverter, or, via appropriate insulation, to wires that are compatible with a power wall outlet. When electrical power is applied through the electrical leads 42, heat is generated by electrical resistance heating of the heating element 48. The heat generated by the heating element 48 is transferred through the thermally conductive laminate layer 46, the hot plate 44, and to the bottom plate 32 of the humidifier tub 20, heating the water in the humidifier tub 20.

[0053] Contact Pad The heating element can include conductive or contact pads 53, 54 that are printed or placed on the laminate layer 46. The conductive pads provide electrical connection points for the electrical leads 42, such as conductive pad 53 providing a positive power terminal and conductive pad 54 providing a negative power terminal. Power flows from a power source through the leads, the power terminals, and the heating element 48. Additional contact pads can be used to provide electrical connection to other electrical device(s) or contacts (e.g., one or more spring contacts) on the laminate layer 46. For example, as shown in FIG. 5, the electrical component 52 described with respect to FIG. 4-1 can include a thermosensor 52A and a thermofuse 52B, which are connected to tracks of the heating element 48. The electrical connection provided by the contact pads 56 (e.g., thermosensor positive terminal) can be between the thermosensor 52A and a separate power source provided by a different set of leads to separately provide power to the thermosensor 52A. A separate power source can be provided if the power requirements of the other electrical device(s) (e.g., thermosensor 52A) are different from the power requirements for the heating element. The thermofuse 52B can be mounted on top of the solder mask and connected to the contact pads in electrical contact with the heating element. In the event of excessive heat, the thermofuse stops the current flow through the heating element. The electrical connection between the contact pads and the electrical leads or sensor wires can be made by soldering or by any other known electrical connection process, such as automated surface mount techniques.

[0054] In an example, a source of nominal voltage between 12 volts (V) and 36 V (such as between 8 V and 40 V) provides power to the heating element 48. Other voltages can be used, subject to appropriate operating parameters of the heating element 48. The heating element 48 can cover substantially the entire area of ​​the laminate layer, while allowing margins for clamping during the coating process to apply the print protection layer 50 (e.g., apply a solder mask).

[0055] Assembly The heating device 36 can be formed using known printed circuit board (PCB) manufacturing techniques for making metal PCBs, such as metal core printed circuit board (MCPCB) techniques. These techniques are highly automated and are adapted to apply conductive tracks onto metal PCBs. In MCPCBs, a metal plate serves both as a printed circuit board base and as a heat sink for electronic components mounted on the plate. Heat from the electronic components is dissipated by the metal plate to avoid overheating of the electronic components. The metal plate can be formed from any suitable thermally conductive metal (e.g., aluminum, stainless steel, or other thermally conductive metals, or thermally conductive polymers or plastics).

[0056] For example, the heating elements 48 can be applied to the thermally conductive laminate layer 46 using MCPCB manufacturing techniques for making metal PCBs. The heating elements can be applied by printing conductive tracks onto the laminate layer 46. The heating elements can also be formed by applying a conductive sheet to the laminate layer, applying a mask to the sheet that is shaped as a mirror image of the desired pattern of the heating elements, and etching the portions of the conductive sheet that are not covered by the mask. The heating elements 48 can also be formed on the laminate layer 46 by vacuum deposition techniques. Furthermore, the serpentine pattern of the heating elements can be selected based on the shape of the bottom of the water tub and the amount of heat energy that is to be delivered to the tub.

[0057] In another example, a PCB including metal layers, dielectric layers, and copper layers can be selected based on size / performance characteristic requirements. Copper heating tracks are created in the copper layers according to track specifications, for example by etching. A print protection layer (e.g., solder mask) is applied to cover the heating tracks. The track / print protection layer can accommodate electrical connection points for surface mounting (or soldering) electrical components (e.g., thermo fuses, thermo sensors).

[0058] The assembly process disclosed herein for the heating devices is fully or nearly fully automated, which allows for the production of heating devices with high quality and uniform consistency. Also, the assembly process disclosed herein can result in reduced assembly costs and reduced repair or replacement costs for the heating elements due to automation. In addition, such PCB technology uses advanced heat transfer structures, materials, and techniques, provides very simple construction, provides excellent thermal performance, involves very few safety concerns, provides easy quality control and high yields, and / or provides easy mass production capacity expansion and large supply.

[0059] Figure 5 shows an example of a heating device 36 formed by a metal printed circuit board printing and manufacturing process. Figure 5 shows heating elements 48 arranged in rows on a thermally conductive laminate layer 46. The laminate layer 46 can be coincident or coextensive with the hot plate 44 (e.g., as shown in Figure 5, which shows the hot plate 44 below the laminate layer 46), or the perimeter of the hot plate 44 can extend slightly beyond the perimeter of the laminate layer 46 (e.g., as shown in Figure 4-1).

[0060] In Figures 3 to 5 described above, the heating device is provided as a separate structure distinct from the humidifier tub, which is adapted to contact the tub and heat the liquid contained inside the tub. Alternatively, the heating device can be integral with the tub, forming the tub bottom, and adapted to directly heat the liquid contained inside the tub. Examples of such direct heating devices are described below.

[0061] FIG. 6 shows a humidifier tub or water tub 60 for heating water 62 in accordance with an example of the present technology. The tub can be adapted to seat in a humidifier chamber or can be provided as a stand-alone device. The tub 60 includes a sidewall 64, or sidewall portion, or tub sidewall, that extends around the entire perimeter of the tub, and a bottom wall 66 that joins the sidewall. A heating device or heating assembly 68 is embedded within the bottom wall 66. In an example, the sidewall 64 and bottom wall 66 (formed, for example, from plastic) are overmolded onto the heating device 68. In the illustrated example, the bottom wall 66 is molded over the peripheral edges of the dielectric layer 72, the heating element 74, and the protective layer 76. In an alternative example, the protective layer can cover one or more layers of the heating device, as described above.

[0062] The heating device 68 is formed as a laminate of a hot plate 70, a thermally conductive dielectric layer 72, a heating element 74, and a protective layer 76. The hot plate can be a metal plate having a first side with an anodized coating, which is adapted to form the bottom interior surface of the tub that is exposed to the water 62. The opposite side of the hot plate receives the thermally conductive dielectric layer 72, which can be a resin with dielectric particles, as described above.

[0063] The heating element 74 can be a serpentine track of metallic foil, for example forming a serpentine track of conductive foil, printed or otherwise applied to the side of the dielectric layer 72 opposite the hot plate 70. Contact pads 78 can be located at each end of the heating element track or near the edge of the hot plate to allow for spring-loaded electrical contact. The contact pads 78 can be exposed through the protective layer 76. Additionally, the contact pads can be formed by raised terminals that protrude slightly from the bottom wall 66 of the tub. Such an arrangement allows the contact pads 78 to engage with power terminals, for example at the bottom of the humidifier chamber that provide power to the heating element. For example, FIG. 13 illustrates a directly heated humidifier tub that includes a heating device 668 that forms the bottom wall of the tub (e.g., the heating device is overmolded or clip-in to the bottom of the tub). 13 shows a heating device hot plate 670, heating element 674, and protective layer 676 with contact pads 678 exposed through protective layer 676. In use, when the tabs are engaged with the humidifier chamber (e.g., a push-down electrical contact connection configuration), the exposed contact pads 678 can engage power terminals or spring-loaded electrical contacts 682 at the bottom of the humidifier chamber.

[0064] A peripheral edge 80 of the hotplate 70 may fit (e.g., snap-fit) into a groove at the lower edge of the sidewall 64. The edge 80 may extend beyond the edges of the protective layer 76, the heating element 74, and the dielectric layer 72. The joint between the edge 80 of the hotplate 70 and the sidewall 64 may be sealed to secure the heating assembly to the sidewall and prevent water leakage from the tub. In an example, the sidewall 64 may be overmolded onto the edge 80 of the hotplate 70, as described above.

[0065] As shown in Figures 11 and 12, the heating assembly can include a protective coating 469, 569 disposed over the hot plate. The protective coating can be overmolded over the hot plate to provide a water and / or steam sealed protective layer over the entire heating surface. The protective coating is thermally conductive to effectively transfer heat from the hot plate to the water in the tub. Moreover, the protective coating is preferably formed from a biocompatible material and can be formed from silicone, Teflon, UV curable polymers, or other thermally conductive plastic materials such as CoolPoly™ products. The protective coating can also provide an easily cleanable surface.

[0066] Moreover, the protective coating can allow the heater assembly to be inserted into or positioned directly within the water tub body, which can provide improved thermal performance. The use of overmolded protective coatings is further described in U.S. Application No. 61 / 611,137, filed March 15, 2012, which is incorporated by reference herein in its entirety.

[0067] FIG. 11 shows an example of a humidifier tub with an open base or bottom. As shown, the tub 460 includes a plastic molded sidewall 464 and a heating device 468 that cooperate to define a water chamber or compartment for water 462. The heating device includes an overmolded protective coating 469, a thermally conductive hot plate 470 (e.g., a metal hot plate), and a heating element 474 having a heating track that abuts the hot plate 470. As shown, the heating device is spaced upward from the lower end of the sidewall 464. The sidewall can be overmolded onto the heating device without a bottom wall or bottom protective layer. Other materials with high thermal insulation can be used for the overmolding. Also, an insulator or bottom wall (not shown) can be provided on the tub below the heating element 474.

[0068] FIG. 12-1 shows an example of a humidifier tub with a closed base or bottom. As shown, the tub 560 includes a plastic molded side wall 564, a plastic molded bottom wall 566, and a heating device 568, which cooperate to define a water chamber or compartment for water 562. The heating device includes an overmolded protective coating 569, a thermally conductive hot plate 570 (e.g., a metal hot plate), and a heating element 574 that provides a heating track. The side and bottom walls can be overmolded onto the heating device.

[0069] 12-2, an inner portion of the tub 560 can be overmolded with a thermally conductive plastic, and a hot plate 570 and heating element 574 are embedded in the overmolding to form a heating device 868. The overmolding 861 includes a bottom wall 867 overmolded over the bottom wall 566 of the tub, and a middle wall 872 that covers the hot plate 570. The overmolding 861 can also include a side wall 863 overmolded over the tub side wall 564. This arrangement can form a biocompatible, washable, water / steam sealed protective layer.

[0070] In an alternative arrangement of the heater assembly, the entire assembly can be formed in a different configuration such that a thermally conductive hot plate is no longer necessary, as shown in Figures 15-1 and 15-2. Referring to Figure 15-1, a support substrate 990 is provided on the lower surface of the tub, onto which a heating element 974 is bonded or applied in the same manner as described above with respect to applying the heating element 48 to the hot plate 44. In another example, the heater assembly can be assembled directly into a surface of the water tub, such as the bottom surface.

[0071] A thermally conductive protective coating 969 is overmolded over the heating element 974 to provide electrical insulation, corrosion resistance, and / or damage protection, as described above. In this arrangement, the heating element 974 is positioned toward the water to be heated, and the support substrate 990 is positioned relatively away from the water. The support substrate 990 serves primarily as a base for receiving printed circuitry and does not function as a heat sink or conductive means for heating the water. In this arrangement, the heater assembly is flipped upside down, as compared to the embodiment described above using a metal hot plate, so that heat transfer occurs in the opposite direction. The heating element 974 is essentially exposed to the water, which can provide improved thermal conductivity and efficiency. Such an arrangement can also provide more accurate or direct temperature sensing of the water.

[0072] The support substrate 990 can be formed from lower cost PCB type materials, such as composite epoxy materials (CEM) of different grades (e.g., CEM3), from fiberglass reinforced epoxy laminates such as FR-4, or from other such PCB type materials. The support substrate 990 can also be configured to provide thermal insulation to the outer surface of the tab.

[0073] In such an arrangement, electrical connections are located on the inner surface of the tub. Electrical connections for temperature sensing or a safety switch can be coupled directly to the heating element 974 prior to overmolding the heating element 974 into the tub.

[0074] As shown in FIG. 15-2, the protective coating or layer 1073 can include a thin layer of stainless steel applied over the heating element 1074. The stainless steel layer can be applied in any suitable manner that provides thermal contact between the stainless steel and the heating element. The thin layer of stainless steel can have a thickness of less than 1.2 mm (e.g., 0.05 to 1 mm). A thermally conductive laminate layer 1075 (e.g., Kapton™ film) can be provided between the protective coating 1073 and the heating element 1074 to provide electrical insulation. The thermally conductive laminate layer 1075 can also include a thermal adhesive (e.g., a double-sided adhesive) to attach the protective layer 1073.

[0075] The stainless steel layer may provide one or more of the following benefits: a protective cover for the heating element, anti-corrosion protection, and high rigidity for the heater assembly (e.g., the stainless steel layer may allow the heater assembly to be formed into a high rigidity structure).

[0076] In another example, the heating element 1074 can be formed without the thick support substrate 1090, with a thin layer of stainless steel providing support for the flexible heater element while also providing a more flexible heater assembly that can be configured to conform to the shape of the water tub.

[0077] Electrical Contacts As noted above, the heating device 68 may have exposed contacts (i.e., exposed contact pads 78) that are engaged by mating contacts adapted to supply power when the tab is placed on the bottom of the humidifier chamber. In such an example, the contacts in the humidifier chamber may be spring loaded such that such contacts must be pressed to effect an electrical connection, e.g., such that the contacts in the humidifier chamber are engaged only when the humidifier lid is closed to hold the humidifier tab in the humidifier chamber.

[0078] 8 to 10 show another example of an electrical connection for a heating device. In this example, a heating device 368 integrated into the bottom of the humidifier tub 360 includes an exposed portion 371 that is adapted to engage an electrical contact structure 380 provided in the humidifier chamber when the tub is slid into an operative position in the humidifier chamber, i.e., a slide-in type electrical connection.

[0079] As shown, the electrical contact structure 380 is in the form of a socket and includes a metal spring arm 382 therein. In use, the exposed portion 371 of the heater device engages the metal spring arm 382 in the electrical contact structure 380, effecting an electrical connection. The advantage of this connection is that there is a "self-cleaning" aspect, whereby any metal oxide build-up on the connection point is removed, as every slide-in / slide-out rubs one surface against another, wiping off any oxide build-up.

[0080] 14A and 14B show another example of a slide-in type electrical connection for a heating device. In this example, a metal spring arm 782 is pivotally mounted in an electrical contact structure 780. In use, an end portion of a heating device 786 can slide into the contact structure 780 and abut against a stub 785, which pivots to lift the spring arm 782 into electrical contact with a contact pad 778 exposed at the bottom of the heating device, e.g., a pivot-type slide-in connection. Such a pivoting connection ensures that in use, only the spring arm 782 contacts the exposed contact pad, i.e., the spring arm avoids contact and potential wear of a protective surface at the bottom of the heating device.

[0081] As shown in FIG. 9-1, a protective contact edge 1183 can be formed in the connector area by overmolding an additional outer protective coating 1192 around at least a portion of the heater assembly. Referring to FIG. 9-1, the heater assembly includes a support substrate 1190, a heating element 1174 (e.g., a copper layer), an overmolded protective coating 1193 on top of the heating element 1174, and an outer protective coating 1192, which is overmolded on a bottom surface of the support substrate 1190 and around the outer edges of the heater assembly to provide a protective coating along the edges of the connector area of ​​the heater assembly. The heating element is exposed from the outer protective coating 1192 in the connector area and can provide a contact portion for the electrical contact arm 1182. The contact area may be protected by a layer of nickel (e.g., 20 μm to 80 μm) and a layer of gold (e.g., 20 μm to 50 μm) over the nickel. An outer protective coating 1192 may provide rigid or semi-rigid support for the heater assembly. The outer protective coating 1192 may also protect the electrical connections from water leakage.

[0082] Temperature Detection Heating device temperature sensing can be provided for fault mitigation and temperature feedback control. For example, the temperature of the heating device or water can be determined and then power to the heating element can be shut off if the temperature is too high. With temperature feedback, the temperature of the heating device or water can be determined to better control the power delivery profile and match the required level of evaporation / humidification.

[0083] The temperature of the heating device or water can be determined in alternative manners. Alternative examples of sensors for determining the temperature of the heating device are described below.

[0084] Non-contact sensors A non-contact type sensor may be provided for determining the temperature of the heating device, such non-contact type sensor being spaced apart from the heating surface or heating track of the heating device.

[0085] In an example, an infrared (IR) sensor can be positioned near the heating surface of the heating device to sense radiation (heat) emanating from the heating device and determine the temperature of the heating device. An example of such an arrangement is shown in Figure 8-1A, which shows an IR sensor 383 near the heating surface of the exposed portion 371 of the heating device.

[0086] In another example, a convection sensor can be positioned near the heating surface of the heating device (e.g., positioned similarly to the sensor shown in FIG. 8-1A) to sense the temperature of the air in the gap between the convection sensor and the heating device to determine the temperature of the heating device.

[0087] Contact Sensor A contact type sensor can be provided for determining the temperature of the heating device, such a contact type sensor being in contact with the heating surface or heating track of the heating device.

[0088] In an example, the sensor may include a thermo-resistant material, the material resistance changing as the temperature changes. By measuring the change in resistance, the temperature may be determined.

[0089] In another example, the sensor can include a thermomagnetic switch, in which the magnetic field strength changes with changes in temperature. By measuring the magnetic field strength change, the temperature can be determined.

[0090] In another example, the sensor can include a bimetallic strip material, where the shape or elasticity of the metal changes with temperature. By measuring the shape or elasticity change, the temperature can be determined. An exemplary advantage of this example is that the strip material can disconnect at a specific temperature, thus providing a thermo fuse for the system. Also, such an off heater sensor arrangement can be a combined sensor and manual resettable switch.

[0091] On-board temperature sensing and thermofuse 5 and described above, a thermosensor 52A can be provided in the heating element to measure the temperature of the heating track, and a thermofuse 52B can be provided to stop current flow through the heating element if the heat becomes excessive. It is also possible for the heating track itself to be the temperature sensor.

[0092] Temperature Sensing Capability In the present technology, the heating device can be formed using known PCB manufacturing techniques for making metal PCBs, such as MCPCB technology. Such a heating device according to the present technology provides a heating profile that is substantially uniformly distributed across the heater device. For example, the temperature difference (ΔT) across the hotplate during heating up is very small (indicating very high thermal conductivity and rapid heat transfer), low thermal stresses on the hotplate and surrounding materials during heating up and operation, low thermal / mechanical stresses on the hotplate and surrounding materials during heating up and operation, and low backside temperature that does not cause the casing bottom to heat up.

[0093] Temperature transfer from the heating track to the metal hotplate is efficient, so the temperature of the hotplate surface is likely to be similar to that of the heating track surface (low temperature gradient / heat sink). Since the track resistance changes with track temperature, current (I) and voltage (V) circuit measurements can be used to calculate the track resistance (R) (R=V / I) and know the R vs. T profile, and the hotplate temperature can be determined by simply determining R. In this way, a separate NTC (negative temperature coefficient) thermistor component may not be needed to sense temperature. Such a conversion circuit can also be used for fault detection and protection, such as heater overheating, open circuit, or loose or short connections.

[0094] Temperature Limiting / Overheat Protection In an example, the heating device according to the present technology can provide a heating surface temperature that can only reach a given maximum temperature for a given input power selected. This is due to efficient heat transfer from the heating track to the heating surface, effective heat dissipation from the heating surface, and the copper heating track reaching a limiting temperature with a given power input. Given this, a thermofuse (to combat and mitigate against overheating) can potentially be eliminated since the heating device has an overheating self-protection capability. Elimination of the thermofuse can result in savings in component and assembly costs.

[0095] In a further example shown in FIG. 9-2, the heating track can be formed from a polymer thick film (PTF) 1274 in combination with a copper conductor (e.g., heating track) 1295 printed on a hot plate (e.g., hot plate 44 described in the above example) or support substrate 1190. The copper conductor 1295 and PTF 1274 are provided in appropriate amounts to provide a heating variation across the heating element. The PTF 1274 can include a positive temperature coefficient (PTC) to provide detection and thermal protection functions. The copper conductor 1295 forms the contact area and serves as a conductor for electricity from the electrical contact arm 1182, and the PTF 1274 serves as a heater. The contact area can be provided with a layer of nickel (e.g., 20 μm to 80 μm) and a layer of gold (e.g., 20 μm to 50 μm) covering the nickel to protect the area. The heater may also be formed by a copper track 1295 in combination with the PTF 1274 to achieve the required heating and protection properties. In an example, one or more sections of the PTF 1274 may be provided with a copper track 1295 in series to form a thermal fuse.

[0096] In an exemplary manufacturing step, the heating device can be surrounded or otherwise covered with stainless steel, which provides the benefit of protecting the heating device from corrosion. This process can be used as an alternative or in conjunction with anodizing the hotplate. The result of this manufacturing step is a heating device that is surrounded or otherwise covered with stainless steel. As an alternative to stainless steel, another thermally conductive material that is scratch resistant and corrosion resistant, such as anodized stamped hard aluminum, can be used to surround or cover.

[0097] The present technology is particularly useful in lower temperature heating applications (e.g., below 100° C., below 80° C., or below 70° C.). Moreover, the power output can be less than about 5 W / cm2, or less than about 2 W / cm2, or less than about 1 W / cm2, for example, approximately 0.6 W / cm2. Higher temperature applications may require a power output of approximately 60 W / cm2. Moreover, the present technology facilitates the use of lower cost materials and lower cost processes than may be required for higher temperature applications. For example, with the present technology, an etching manufacturing process can be used instead of printing thermally conductive ink. The etching process can produce more accurate heating tracks than the printing process. Moreover, high temperature processes and applications require inorganic dielectrics and the associated higher material and process costs, whereas the present technology allows the use of less expensive dielectric materials, such as organic materials. Moreover, the present technique allows for the use of lower cost hotplates, such as hotplates made from aluminum or other lower cost materials.

[0098] Although the present technology has been described in connection with several examples, it should be understood that the present technology should not be limited to the disclosed examples, but on the contrary, is intended to cover various modifications and equivalent configurations falling within the spirit and scope of the present technology. Also, the various examples described above can be implemented in conjunction with other examples, for example, one or more aspects of one example can be combined with one or more aspects of another example to achieve yet another example. Moreover, each independent feature or component of any given assembly can constitute an additional example. In addition, while the present technology has particular application to patients suffering from OSA, it should be recognized that patients suffering from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, bariatric surgery, etc.) can benefit from the above teachings. Moreover, the above teachings have applicability to patients and non-patients in non-medical applications as well.

[0099] [Additional note 1] a tab adapted to hold a liquid; A heating device comprising a substrate having etched heating tracks; A humidifier comprising: [Additional note 2] The humidifier of claim 1, wherein the substrate includes a thermally conductive substrate layer, a layer of copper or alloy or positive temperature coefficient (PTC), and a dielectric laminate layer between the thermally conductive substrate layer and the copper or alloy or PTC layer. [Additional note 3] 3. The humidifier according to claim 2, wherein the thermally conductive substrate layer is made of metal. [Additional note 4] 4. A humidifier according to any one of claims 2 to 3, wherein the dielectric laminate layer is made of a ceramic material, a polymer material, or a mixture material of ceramic and polymer. [Additional note 5] 5. The humidifier of any one of claims 2 to 4, wherein the heating tracks are etched into the copper or alloy or PTC layer. [Additional note 6] 6. The humidifier of claim 5, wherein the heating track is associated with electrical leads and contact pads for at least one electrical component. [Additional note 7] 7. The humidifier of any one of claims 5 to 6, wherein the heating track comprises a width in the range of about 0.4 mm to 2 mm. [Additional note 8] 8. The humidifier of any one of claims 5 to 7, wherein the temperature of the heating device is determined by determining the resistance of the heating track. [Additional note 9] 9. The humidifier of any one of claims 2 to 8, further comprising a protective layer printed on at least the copper or alloy or PTC layer. [Additional Note 10] 10. The humidifier of any one of claims 1 to 9, wherein the heating device provides a heating surface temperature that can only reach a maximum temperature for a selected input power. [Additional Note 11] 11. The humidifier of any one of claims 1 to 10, wherein the heating device is provided in a humidifier chamber adapted to receive the tab. [Additional Note 12] 11. The humidifier of any one of claims 1 to 10, wherein the heating device is integral with the tub. [Additional Note 13] a tab adapted to hold a liquid; a heating device including a metal hot plate, a heating element with a copper or alloy or PTC heating track for providing heat to heat the liquid, a thermally conductive laminate layer made of a ceramic or polymer material between the hot plate and the heating element, and a printed protective layer for covering at least the heating track; A humidifier comprising: [Additional Note 14] a tab adapted to hold a liquid; a heating device including a hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer for covering at least the heating element; A humidifier comprising: A humidifier, wherein the heating element comprises a layer of copper or alloy or PTC having a heating track for providing heat to heat the liquid. [Additional Note 15] 15. The humidifier of claim 14, wherein the heating track is etched into the copper or alloy or PTC layer of the heating device. [Additional Note 16] 16. The humidifier of any one of claims 14 to 15, wherein the heating track is associated with electrical leads or spring contacts and contact pads for at least one electrical component. [Additional Note 17] 17. The humidifier of any one of claims 14 to 16, wherein the heating track comprises a width in the range of approximately 0.3 mm to 2 mm. [Additional Note 18] 18. The humidifier of any one of claims 14 to 17, wherein the temperature of the heating device is determined by determining the resistance of the heating track. [Additional Note 19] 19. The humidifier of any one of claims 14 to 18, wherein the hot plate is formed from a metal or metal alloy including at least one of aluminum, stainless steel, and copper. [Additional Note 20] a tab adapted to hold a liquid; a heating device including a hot plate, a heating element, a thermally conductive laminate layer between the hot plate and the heating element, and a protective layer for covering at least the heating element; A humidifier comprising: A humidifier, wherein the protective layer is printed over at least the heating element. [Additional Note 21] 21. The humidifier of claim 20, wherein the laminate layer is a dielectric laminate layer made of a ceramic material, a polymer material, or a polymer blend material. [Additional note 22] 22. The humidifier of any one of claims 20 to 21, wherein the protective layer is printed on the laminate layer. [Additional Note 23] 23. The humidifier of claim 22, wherein the protective layer extends over a peripheral edge of the heating element and over a portion of the laminate layer. [Additional note 24] 24. The humidifier of any one of claims 20 to 23, wherein the protective layer comprises a solder mask. [Additional note 25] 25. The humidifier according to any one of claims 20 to 24, wherein the thermally conductive laminate layer has a thickness in the range of about 20 μm to 160 μm. [Additional note 26] 26. The humidifier of any one of claims 20 to 25, wherein the hot plate is formed from a metal or metal alloy including aluminum, stainless steel, or copper. [Additional note 27] 27. The humidifier of any one of claims 20 to 26, wherein contact pads and / or other conductive parts of the heating element are exposed through the protective layer. [Additional note 28] 1. A process for making a heating device for a humidifier including a tub for holding a liquid, comprising: providing a substrate having a first side adapted for thermal contact with the liquid and a second side; Etching heater tracks on the second side of the substrate; applying a protective layer to the second side of the substrate to at least cover the heating tracks; A process comprising: [Additional note 29] 29. The process of claim 28, wherein the step of providing the 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. [Additional note 30] 30. The process of any one of clauses 28 to 29, wherein applying the protective layer comprises printing the protective layer on the second side of the substrate. [Additional Note 31] 31. The process of any one of claims 28 to 30, wherein the step of applying the protective layer includes a step of exposing contact pads and / or other conductive portions associated with the heating tracks through the protective layer. [Additional note 32] a heating element that converts electrical power into thermal energy; a heatable element having a first surface and a second surface; a dielectric laminate layer between the heating element and the first surface of the heatable element; A heating device comprising: The dielectric laminate layer is thermally conductive to transfer thermal energy from the heating element to the heatable element, and the second surface of the heatable element is configured to heat a liquid in a container. [Additional note 33] 33. The heating device 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. [Additional note 34] 34. The heating device of claim 33, wherein the protective layer extends over the peripheral edges of the heating element and the dielectric laminate layer and over a peripheral portion of the first surface of the heatable element that extends beyond the heating element and the dielectric laminate layer. [Additional note 35] 35. The heating device of any one of claims 32 to 34, wherein the dielectric laminate layer is a thin layer comprising at least one of polytetrafluoroethylene, such as Teflon®, polyimide, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composites, and fiberglass reinforcement. [Additional note 36] 36. The heating device of any one of claims 32 to 35, wherein the dielectric laminate layer has a thickness in the range of 20 μm to 160 μm. [Additional note 37] 37. The heating device of any one of claims 32 to 36, wherein the dielectric laminate layer has a breakdown voltage of more than 2 kV. [Additional note 38] 38. The heating device of any one of claims 32 to 37, wherein the heatable element comprises a plate made of a conductive metal, and the first and second surfaces are opposing surfaces of the plate. [Additional note 39] 39. The heating device of any one of claims 32 to 38, wherein the heating element comprises a conductive metal foil disposed in a serpentine pattern on the dielectric laminate layer. [Additional note 40] 40. The heating device of any one of claims 32 to 39, wherein the heating element is a metal printed circuit board (PCB), the heating element comprising a conductive metal foil track disposed on the PCB. [Additional note 41] 41. The heating device of any one of claims 32 to 40, wherein the thickness of the device is no greater than 1.5 mm. [Additional note 42] 42. The heating device of any one of claims 32 to 41, wherein the second surface is flat. [Additional note 43] A heating element track; a thermally conductive dielectric layer; a thermally conductive board having a first surface adapted to transfer heat into the container and a second surface opposite the first surface, on which the thermally conductive dielectric layer is sandwiched between the board and the heating element track; A printed circuit board heater comprising: A printed circuit board heater, wherein electrical current terminals to the heating track provide for application of electrical energy to the heating element track causing resistive heating of the heating track, and thermal energy from the heating element track is transferred through the thermally conductive dielectric layer to the board, which transfers the thermal energy to the vessel. [Additional note 44] 44. The printed circuit board heater of claim 43, wherein the printed circuit board heater is integral with a surface of the container. [Additional note 45] 45. The printed circuit board heater of claim 44, wherein the first surface is configured to receive a bottom surface of the container. [Additional note 46] 46. ​​A printed circuit board heater according to any one of claims 43 to 45, further comprising a protective layer covering the heating element track layer and the dielectric layer. [Additional note 47] 47. The printed circuit board heater of claim 46, wherein the protective layer extends over a peripheral edge of the heating element track and dielectric layer and over a peripheral portion of the first surface of the board extending beyond the heating element track and the dielectric layer. [Additional note 48] 48. The printed circuit board heater of any one of claims 43 to 47, wherein the thermally conductive dielectric layer is a thin layer comprising at least one of polytetrafluoroethylene, such as Teflon®, polyimide, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composites, and fiberglass reinforcement. [Additional note 49] 49. The printed circuit board heater of any one of claims 43 to 48, wherein the thermally conductive dielectric layer has a thickness in the range of 20 μm to 160 μm. [Additional Note 50] 50. The printed circuit board heater of any one of claims 43 to 49, wherein the thermally conductive dielectric layer has a breakdown voltage of greater than 2 kV. [Additional note 51] 51. The printed circuit board heater of any one of claims 43 to 50, wherein the thermally conductive board is formed from a metal or metal alloy plate, including an aluminum, stainless steel, or copper plate. [Additional note 52] 52. The printed circuit board heater of any one of claims 43 to 51, wherein the heating element track layer comprises a conductive metal foil arranged in a serpentine pattern on the dielectric layer. [Additional note 53] 53. A humidifier comprising a container for holding a quantity of liquid and a heating device according to any one of claims 32 to 52, wherein the heating device is in thermal contact with the liquid to deliver heat to the liquid and cause an airflow from evaporation of the liquid. [Additional note 54] providing a substrate having a first surface adapted to heat a liquid in a vessel; applying a thermally conductive dielectric layer to a second surface of the substrate, the second surface being opposite the first surface; applying the 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; 16. A method of forming a heating device comprising: [Additional note 55] 55. The method of claim 54, further comprising applying a protective layer to the heating element layer and the thermally conductive dielectric layer. [Additional note 56] 56. The method of claim 54 or 55, wherein the substrate is a metal plate and the method is carried out using processing of a metal core printed circuit board. [Additional note 57] 57. The method of any one of clauses 54 to 56, wherein the heating element layer is applied as a serpentine track of conductive foil on the thermally conductive dielectric layer. [Additional note 58] 58. The method of any one of claims 54 to 57, wherein the thermally conductive dielectric layer is applied as a composite layer of dielectric particles and resin. [Additional note 59] 59. The method of any one of clauses 54 to 58, further comprising the step of integrating the formed heating plate with a bottom of the liquid container. [Additional note 60] 60. The method of any one of claims 54 to 59, further comprising printing the heating element layer as a serpentine pattern on the thermally conductive dielectric layer. [Additional note 61] a tab adapted to hold a liquid; a heating device including a heating element having a first side and a second side, the heating element including a heating track; a first thermally conductive laminate layer disposed on the first side of the heating element; a second thermally conductive laminate layer disposed on the second side of the heating element; and A humidifier comprising: [Additional note 62] 62. The humidifier of claim 61, wherein a substrate is provided at an end portion of the heating element and forms a connection portion. [Additional note 63] 63. The humidifier of claim 62, wherein the end portions of the heating element form electrical contacts for receiving electrical power. [Additional note 64] a tub having an inner portion adapted to hold a liquid; a heating device including a hot plate and a heating element disposed on a first side of the hot plate; an overmold formed on the inner portion of the tub, the overmold completely surrounding the heating device such that the heating device is embedded within the overmold; A humidifier comprising: [Additional note 65] 65. The humidifier of claim 64, wherein the overmold comprises a thermally conductive plastic. [Additional note 66] 66. A humidifier according to any one of claims 64 to 65, wherein the tub includes a side wall portion and the overmold includes a side wall portion formed over the side wall portion of the tub. [Additional note 67] 67. The humidifier of any one of claims 64 to 66, wherein the hot plate is formed from a thermally conductive material, including metal, a metal alloy, aluminum, stainless steel, copper, or a thermally conductive plastic. [Additional note 68] a tub having an inner portion adapted to hold a liquid; a heating device including a support substrate and a heating element disposed on a first side of the support substrate, the support substrate being distal to the inner portion of the tab and the heating element being proximal to the inner portion of the tab; a first thermally conductive protective layer provided on the heating element; A humidifier comprising: [Additional note 69] 69. The humidifier of claim 68, wherein the first protective layer is overmolded over the heating element. [Additional note 70] 70. The humidifier of any one of claims 68 to 69, wherein the support substrate comprises at least one of a composite epoxy material (CEM) and a fiberglass reinforced epoxy laminate. [Additional note 71] 71. The humidifier of any one of clauses 68 to 70, wherein the first protective layer comprises stainless steel. [Additional note 72] 72. The humidifier of any one of claims 68 to 71, further comprising an electrically insulating layer between the first protective layer and the heating element. [Additional note 73] 73. A humidifier as described in any one of claims 68 to 72, further comprising a second thermally conductive protective layer provided on a second side of the support substrate and on an edge portion of the support substrate. [Additional note 74] 74. The humidifier of any one of claims 68 to 73, wherein an end portion of the heating element is exposed from the first protective layer and provides electrical contacts for receiving power. [Additional note 75] 75. The humidifier of any one of clauses 68 to 74, wherein the heating element comprises a polymer thick film (PTF). [Explanation of symbols]

[0100] 10 respirator, 12 flow generator, 14 humidifier, 16 humidifier chamber, 18 lid, 20 humidifier tub, 22 tub lid, 24 channel, 26 outlet, 28 gas outlet, 30 tub bottom, bottom container, 32 bottom plate, 36, 68, 368, 468, 568, 668, 786, 868 heating device, 38 insulation layer, 40 cradle bottom, 42 electrical leads, 43 control device, 44, 70, 470, 570, 670 hot plate, 46 laminate layer, 48, 74, 248, 474, 574, 674, 974, 1074, 1174 heating element, 50 protective layer, printed protective layer, 52 electrical components, 52A thermosensor, 52B Thermofuses, 53, 54, 56, 678, 778 Contact pads, 59 Connections, 60, 360, 560 Tabs, 61 Contacts, 62, 462, 562 Water, 63 Electrical contacts, 72 Dielectric layer, 76 Protective layer, 78 Contact pads, 80 Edges, 380 Electrical contact structure, 382, ​​782 Spring arms, 383 IR sensors, 469, 569, 969, 1073, 1193 Protective coating, 676 Protective layer, 682 Spring-loaded electrical contacts, 780 Electrical contact structure, 785 Stubs, 990 Support substrate, 1075 Laminate layer, 1090 Support substrate, 1182 Electrical contact arms, 1183 Protective contact edges, 1190 Support substrate, 1192 Outer protective coating, 1274 Polymer thick film (PTF), 1295 copper track, copper conductor

Claims

1. 1. A humidifier for humidifying a pressurized flow of breathable gas in respiratory therapy for a patient, comprising: a tub adapted to hold a liquid, the tub having a sidewall; A heating device; Equipped with The heating device comprises: a heating element configured to convert electrical power into thermal energy; a thermally conductive hotplate having a first surface and a second surface, the first surface of the hotplate adapted to receive thermal energy from the heating element and the second surface of the hotplate configured and adapted to heat a liquid in the tub and configured to act as a heat sink, the heat sink drawing thermal energy from the heating element and storing it in the heat sink for use in heating the liquid in the tub; a protective coating overmolded over the hotplate to form a sealed protective layer over the second surface of the hotplate; having the hot plate is formed of a material different from that of the side wall portion, A humidifier, wherein the hot plate is a metal plate or a ceramic plate.

2. the heating apparatus further comprising a dielectric laminate layer between the heating element and the first surface of the hotplate; 10. The humidifier of claim 1, wherein the dielectric laminate layer is thermally conductive and transfers thermal energy from the heating element to the hot plate.

3. 3. The humidifier of claim 2, wherein the dielectric laminate layer is a thin layer comprising at least one of polytetrafluoroethylene, polyimide, boron nitride, alumina, beryllium oxide, aluminum nitride, boron nitride, epoxy composite, and fiberglass reinforcement.

4. 2. The humidifier of claim 1, wherein the heating element is in direct contact with the first surface of the hot plate.

5. 5. A humidifier as claimed in any preceding claim, wherein the protective coating provides a water and / or vapour sealed protective layer over the second surface of the hotplate.

6. 6. The humidifier of claim 1, wherein the protective coating is thermally conductive and efficiently transfers heat from the hot plate to the liquid in the tub.

7. 7. A humidifier according to any preceding claim, wherein the protective coating is formed from a biocompatible material.

8. 8. The humidifier of claim 7, wherein the protective coating is formed from a silicone or a UV curable polymer.

9. the tub having a bottom with a bottom outer wall of the tub; 9. A humidifier as claimed in any preceding claim, wherein the bottom outer wall is spaced upwardly from the lower end of the side wall such that the tub has an open bottom.

10. 10. The humidifier of claim 9, wherein the heating device forms the bottom exterior wall of the tub.

11. the tub has a bottom with a bottom outer wall that is below the heating device; 9. The humidifier according to claim 1, wherein the bottom outer wall portion is connected to a lower end of the side wall portion.

12. 12. A humidifier according to any preceding claim, wherein the side wall is overmolded onto the heating device.

13. 13. A humidifier as claimed in any one of claims 1 to 12, wherein the side wall is made from plastic.

14. 14. The humidifier of any one of claims 1 to 13, wherein the hot plate is a metal plate and comprises aluminum, stainless steel or copper.

15. 14. The humidifier according to claim 1, wherein the hot plate is a ceramic plate.

16. 16. A humidifier according to any one of claims 1 to 15, wherein the heating element comprises a heating track.

17. the heating element is a metal printed circuit board (PCB); 17. The humidifier of claim 16, wherein the heating track is a conductive metal foil disposed on the printed circuit board.

18. 18. The humidifier of claim 17, wherein a substrate is provided at an end portion of the heating element forming a connector section, the end portion of the heating element making electrical contact and receiving electrical power.

19. 19. A humidifier according to any one of claims 1 to 18, characterized in that the heating device is arranged in a lower portion of the tub.

20. 20. A humidifier according to any preceding claim, wherein the protective coating comprises a polymer.

21. a gas inlet configured to receive gas from a flow generator; a gas outlet configured to deliver humidified gas to a patient interface; 21. The humidifier of claim 1, further comprising:

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