Heating assembly for an aerosol generating device

Abstract

A heating assembly (200) for an aerosol generating device (100) is disclosed. The heating assembly (200) comprises a metallic tubular heating chamber (202) with an opening (204) for receiving an aerosol substrate. A coating of electrically insulating material (206) at least partially surrounds an outer surface (203) of the heating chamber (202), the coating of electrically insulating material (206) comprising one or more of ceramic, glass, silicone, and carbon. A heating element (208) at least partially surrounds the heating chamber and is disposed against the coating of electrically insulating material (206), the coating of electrically insulating material (206) preventing any contact between the heating element (208) and the heating chamber (202).

Description

[Technical Field]

[0001] The present disclosure relates to a heating assembly for an aerosol generating device and a method for manufacturing a heating assembly for an aerosol generating device. The disclosure is particularly applicable to portable aerosol generating devices that may be self-contained and low-temperature. Such devices may heat tobacco or other suitable aerosol substrate materials by conduction, convection, and / or radiation, rather than by combustion, to generate an aerosol for inhalation. [Background technology]

[0002] The popularity and use of risk-reducing or risk-modifying devices (also known as vaporizers) has grown rapidly in recent years as an aid to assisting regular smokers who wish to quit using traditional tobacco products, such as cigarettes, cigars, cigarillos, and roll-up cigarettes. A variety of devices and systems are available that heat or warm an aerosolizable substrate, as opposed to burning tobacco in traditional tobacco products.

[0003] Commonly available risk reduction or risk modification devices are substrate-heated aerosol generating devices or heat-and-burn devices. These types of devices generate an aerosol or vapor by heating an aerosol substrate, i.e., a consumable, typically containing moist tobacco or other suitable aerosolizable material, to temperatures typically ranging from 150°C to 300°C. By heating rather than burning or combusting the aerosol substrate, an aerosol is released that contains the components desired by the user but is free of the undesirable by-products of combustion and burning. Furthermore, aerosols generated by heating tobacco or other aerosolizable material typically do not contain the burnt or bitter taste that can result from combustion, which can be unpleasant to users.

[0004] In known heat-non-combustion devices, it is desirable to improve the efficiency of the heating process while maintaining a compact device with reliable operation. Summary of the Invention [Means for solving the problem]

[0005] According to a first aspect of the present invention, there is provided a heating assembly for an aerosol generating device comprising: a metallic tubular heating chamber having an opening for receiving an aerosol substrate; a coating of electrically insulating material at least partially surrounding an outer surface of the heating chamber, the coating comprising one or more of ceramic, glass, silicone, and carbon; and a heating element at least partially surrounding the heating chamber and disposed opposite the coating of electrically insulating material, the coating of electrically insulating material preventing any contact between the heating element and the heating chamber.

[0006] In this way, a more efficient heating assembly is provided compared to known aerosol generating devices. The arrangement and properties of the electrically insulating material coating prevent short circuits from occurring between the metallic heating chamber and the heating element while enabling improved heat transfer from the heating element to the aerosol substrate received within the heating chamber. In particular, the use of ceramic, glass, silicone, and / or carbon as the coating material provides a high breakdown voltage, e.g., 1000 V / mm, so that short circuits can be prevented using only a thin coating layer, e.g., 10 μm, while also providing high thermal conductivity to ensure efficient transfer of heat to the heating chamber through the electrically insulating material coating. In contrast, in known devices, a separate (i.e., different) electrically insulating film, such as PEEK or polyimide, is generally provided between the heating element and the heating chamber. This increases the bulk of the device and provides lower thermal conductivity, thereby increasing the time required to heat the heating chamber and reducing heating efficiency. The present invention eliminates the need for such a film while also improving heat transfer characteristics, thereby improving the effectiveness of the heating assembly. Additionally, using a coating rather than a separate electrically insulating film greatly simplifies the manufacturing process.

[0007] The term "coating" refers to a layer formed during application of an electrically insulating material to the exterior surface of a heat chamber. A coating does not exist as a separate layer prior to its application. In particular, a coating may be defined as a layer formed by applying a liquid, vapor, or gaseous material to the exterior surface of a heat chamber. This is in contrast to films, such as PEEK or polyimide films, which are preformed and exist as a separate layer prior to their application.

[0008] Preferably, the electrically insulating coating is formed as a rigid layer on the outer surface of the heat chamber, in contrast to conventional electrically insulating films such as PEEK or polyimide, which are applied as a flexible layer on the outer surface of the heat chamber.

[0009] Preferably, the coating of electrically insulating material is formed using one of vapor deposition, painting, dipping, or spraying. In this manner, the coating of electrically insulating material exhibits advantageous mechanical and electrical properties compared to a film of electrically insulating material that is pre-formed (e.g., a polyimide film) and then attached to the exterior surface of the heating chamber. For example, the coating of electrically insulating material conforms to the specific shape of the exterior surface of the heating chamber, in contrast to a pre-formed film that is not formed close to the surface, resulting in suboptimal heat transfer.

[0010] Preferably, the coating of electrically insulating material comprises ceramic and glass, ceramic and silicone, or glass and silicone. More preferably, the coating of electrically insulating material comprises ceramic, glass, and silicone. In this manner, the coating of electrically insulating material provides significantly improved thermal conductivity compared to using typical electrically insulating films comprising polyetheretherketone (PEEK) or polyimide. In particular, the inclusion of glass and ceramic within silicone provides high temperature resistance (e.g., a temperature rating of 482°C) and high thermal conductivity, while allowing for the formation of a thin coating.

[0011] Preferably, the coating of electrically insulating material consists of diamond-like carbon (DLC).

[0012] Preferably, the heating assembly further comprises a flexible electrically insulating film wrapped around the heating chamber on the opposite side of the coating of electrically insulating material from the heating element. In this way, the heating element is electrically insulated from other components inside the aerosol generating device. In one embodiment, the heating element may be supported on a flexible electrically insulating film, and the heating element is attached to the coating of electrically insulating material by wrapping the flexible electrically insulating film around the heating chamber containing the heating element against the coating of electrically insulating material. In another embodiment, the heating element may be supported on a carrier film, and the heating element may be wrapped around the coating of electrically insulating material using the carrier film. Once the heating element is positioned, the carrier film may be removed, and the flexible electrically insulating film may then be wrapped around the heating chamber.

[0013] Preferably, the flexible electrically insulating film is configured to secure the heating element against the coating of electrically insulating material.

[0014] Preferably, the flexible electrically insulating film comprises a heat shrink film, which in this way ensures that the heating element remains in contact with the coating of electrically insulating material while also maintaining a compact arrangement of the heating assembly.

[0015] In some embodiments, the heating element is attached to the coating of electrically insulating material using an adhesive.

[0016] In some embodiments, the heating assembly further comprises a thin film heater comprising a heating element and a flexible backing film on which the heating element is supported, the thin film heater being wrapped around the heating chamber with the heating element facing the coating of electrically insulating material.

[0017] Preferably, the coating of electrically insulating material surrounds the outer surface of the heat chamber and the heating element surrounds the heat chamber, particularly the coating of electrically insulating material surrounds the outer periphery of the heat chamber.

[0018] Preferably, the heating element comprises a resistive metal track.

[0019] Preferably, the coating of electrically insulating material has a thickness of between 0.8 and 20 microns, preferably between 3 and 18 microns, For example, the coating of electrically insulating material may have a thickness of 3 microns, 5 microns, 10 microns, 12.5 microns, 15 microns, or 20 microns.

[0020] Preferably, the coating of electrically insulating material has a dielectric breakdown strength of at least 500 V / mm, more preferably at least 1000 V / mm.

[0021] According to a second aspect of the present invention, there is provided a method of manufacturing a heating assembly according to any one of the preceding claims, the method comprising applying a coating of electrically insulating material to an outer surface of a heating chamber by one of vapor deposition, painting, dip coating or spraying.

[0022] Preferably, the method further includes curing the coating of electrically insulating material at a temperature of at least 80° C. In particular, coatings of electrically insulating material comprising ceramic, glass, and silicone may be thermally cured after being applied to the exterior surface of the heating chamber. For example, the coating of electrically insulating material may be cured at 95° C. for 15 minutes, then at 250° C. for 15 minutes, then at 540° C. for 10 minutes.

[0023] In one embodiment, the method further includes supporting the heating element on a carrier film; wrapping the heating element with the carrier film around the heat chamber such that the heating element is disposed against the coating of electrically insulating material; removing the carrier film; and wrapping a flexible electrically insulating film around the heat chamber such that the heating element is disposed between the flexible electrically insulating film and the coating of electrically insulating material.

[0024] In another embodiment, the method further includes supporting the heating element on a flexible electrically insulating film and wrapping the flexible electrically insulating film around the heating chamber such that the heating element is disposed against the coating of electrically insulating material.

[0025] Preferably, the method further comprises heating the flexible electrically insulating film, which is a heat shrink film, such that the heating element is secured to the coating of electrically insulating material.

[0026] According to a third aspect of the present invention, there is provided an aerosol generating device comprising a heating assembly according to the first aspect.

[0027] A number of embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0028] [Figure 1] 1 is an exemplary aerosol generating device according to one embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a heating assembly according to one embodiment of the present invention. [Figure 3] 3 is a cross-sectional schematic view of the heating assembly of FIG. 2 further comprising a flexible electrically insulating film. [Figure 4] FIG. 2 is a flow diagram illustrating method steps for manufacturing a heating assembly according to one embodiment of the present invention. [Figure 5] FIG. 3 is a perspective view of the heating assembly of FIG. 2, showing application of the heating element with a carrier film. DETAILED DESCRIPTION OF THE INVENTION

[0029] FIG. 1 illustrates an aerosol generating device 100 according to an embodiment of the present invention. The aerosol generating device 100 is shown in an assembled configuration so that the internal components are visible. The aerosol generating device 100 is a heat-non-combustion device, sometimes referred to as a tobacco vapor device, and includes a heating assembly 200 configured to receive an aerosol-generating material, e.g., an aerosol substrate such as a tobacco rod. The heating assembly 200 is operable to heat, rather than burn, the rod of aerosol-generating material to generate a vapor or aerosol for inhalation by a user. Of course, those skilled in the art will appreciate that the aerosol generating device 100 illustrated in FIG. 1 is merely an exemplary aerosol generating device according to the present invention. Other types and configurations of tobacco vapor products, vaporizers, or electronic cigarettes may also be used as aerosol generating devices according to the present invention.

[0030] FIG. 2 shows a perspective view of a heating assembly 200 according to one embodiment of the present invention. Similarly, FIG. 3 shows a cross-sectional schematic view of the heating assembly 200, except that the heating assembly 200 further includes a flexible, electrically insulating film 210 wrapped around the heating assembly 200. The heating assembly 200 includes a heating chamber 202, also referred to as a thermally conductive shell, configured to hold an aerosol substrate, also referred to as a consumable, therein. In particular, the heating chamber 202 defines a cylindrical cavity in which a rod of aerosol substrate may be positioned. The heating chamber 202 is tubular, e.g., cylindrical, and has an opening 204 positioned at a longitudinal end of the heating chamber 202. During use, a user may insert the aerosol substrate through the opening 204 of the heating chamber 202 such that the aerosol substrate is positioned within the heating chamber 202 and interfaces with the inner surface 201 of the heating chamber 202. The length of the heating chamber 202 may be configured so that a portion of the aerosol substrate can protrude through the opening 204 of the heating chamber 202, i.e., outside the heating assembly 200, and be received by the mouth of a user.

[0031] Heat chamber 202 comprises, and preferably consists of, metal to provide efficient transfer of heat to the aerosol substrate through the sidewalls of heat chamber 202 while also ensuring that heat chamber 202 has sufficient structural stability and durability. Examples of suitable metals include steel or stainless steel.

[0032] The thickness of the tubular sidewall of the heating chamber is preferably 0.1 mm or less, or more preferably between 0.07 and 0.09 mm. This allows for efficient heat conduction through the sidewall of the heating chamber 202 to the consumable while maintaining sufficient structural stability. The tubular member has a closed end opposite the opening 204, and preferably the thickness of the closed end is 0.2 to 0.6 mm, which adds further structural rigidity to the heating chamber. A method of manufacturing the heating chamber 202 is described in co-pending PCT application PCT / EP2020 / 074147.

[0033] The heating chamber 202 may include a plurality of inwardly protruding elongated ridges as shown in Figure 5. The elongated ridges may be created by injecting a fluid under pressure into the tubular member, forcing it into the outer surface of the tubular member to provide a plurality of corresponding elongated protrusions running lengthwise on the inner surface of the tubular member.

[0034] Those skilled in the art will appreciate that heating chamber 202 is not limited to being tubular. For example, heating chamber 202 may be formed as a cubic, conical, hemispherical, or other shaped cavity and configured to receive an aerosol substrate of a complementary shape. Moreover, in some embodiments, heating chamber 202 may not completely surround the aerosol substrate, but instead may contact only a limited area of ​​the aerosol substrate.

[0035] A coating of electrically insulating material 206, also referred to as an electrically insulating layer, surrounds the exterior surface 203 of the heat chamber 202. In particular, the coating of electrically insulating material 206 is located adjacent to (i.e., abuts or contacts) the circumferential exterior surface 203 of the heat chamber 202. That is, the coating of electrically insulating material 206 is directly bonded to the exterior surface 203 of the heat chamber 202. In FIGS. 1 and 2, the coating of electrically insulating material 206 is shown as extending along only a portion of the length of the exterior surface 203 of the heat chamber 202. However, those skilled in the art will appreciate that in other embodiments, the coating of electrically insulating material 206 may extend along the entire length of the heat chamber 202. Moreover, those skilled in the art will appreciate that the coating of electrically insulating material 206 may only partially surround the exterior surface of the heat chamber 202.

[0036] The electrically insulating material coating 206 comprises at least one of ceramic, glass, silicone, and carbon, or any combination thereof. Preferably, the electrically insulating material coating 206 comprises (and optionally consists of) silicone, glass, and ceramic. This combination of components provides a high breakdown voltage, e.g., between 100 and 1000 V / mm, and exhibits high thermal conductivity compared to, e.g., polyimides used in typical electrically insulating films. Furthermore, a thin coating, e.g., 10 μm, may be used to provide improved heat transfer to the aerosol substrate received within the heating chamber 202. In comparison, polyimides have a thickness of approximately 25 microns. Such properties advantageously reduce the heating and cooling times of the heating chamber 202 and improve the energy efficiency of the heating assembly 200. Advantageously, such coating materials may also have higher thermal stability than polyimides. For example, silicone glass is stable up to approximately 482°C, DLC is stable up to 300°C, and silicone-modified alkyd is stable up to 450°C, while polyimide is stable only up to 270°C. In other embodiments, the coating 206 of electrically insulating material may comprise (and optionally consist of) diamond-like carbon (DLC) or silicone modified alkyd resin.

[0037] The coating of electrically insulating material 206 may be deposited using a variety of coating or deposition techniques, as discussed further with reference to FIG.

[0038] A heating element 208 comprising one or more heater tracks surrounds a coating of electrically insulating material 206. In particular, the heating element 208 is wrapped, e.g., circumferentially, around the heating chamber 202 such that the heating element 208 is located adjacent to (i.e., abutting, contacting) the coating of electrically insulating material 206. The coating of electrically insulating material 206 acts as a barrier separating the heating element 208 and the heating chamber 202 such that contact between the heating element 208 and the heating chamber 202 is prevented. Those skilled in the art will appreciate that the heating element 208 may only partially surround the heating chamber 202 and / or one or more heating elements 208 may be disposed about the periphery of the heating chamber 202.

[0039] The heating element 208 comprises a heating material suitable for converting electrical energy into heat (such as stainless steel, titanium, nickel, nichrome, nickel-based alloys, silver, etc.). In the illustrated embodiment, the heating element 208 comprises one or more resistive heater tracks. However, in other embodiments, the heating element 208 may be formed in alternative configurations, for example, as a heated sheet.

[0040] During use, power may be supplied to the heating element 208 from a power source, such as a battery (not shown), such that the temperature of the heating element 208 increases and thermal energy is transferred to the heating chamber 202 across the coating of electrically insulating material 206. An aerosol substrate received within the heating chamber 202 is conductively heated by the heating chamber 202 to generate an aerosol for inhalation by a user.

[0041] Those skilled in the art will appreciate that the heating chamber 202 is not a resistive heater and therefore should not receive electrical current. Therefore, the coating 206 of electrically insulating material advantageously prevents short circuits from occurring between the heating element 208 and the heating chamber 202 while allowing efficient transfer of heat from the heating element 208 to the heating chamber 202. That is, the coating 206 of electrically insulating material separates the heating element 208 from the heating chamber 202, ensuring that electrical current does not flow from the heating element 208 to the heating chamber 202. This eliminates the need for an additional layer of polyimide or PEEK that is often wound between the heating chamber 202 and the heating element 208 in conventional aerosol generating devices. Furthermore, those skilled in the art will appreciate that the coating 206 of electrically insulating material is provided with a small thickness, which may improve the efficiency of heat transfer from the heating element 208 to the heating chamber 202.

[0042] 3, a layer of electrically insulating film 210 is wrapped around the heating chamber 202 on the opposite side of the heating element 208 from the coating of electrically insulating material 206. That is, the heating element 208 is sandwiched between the coating of electrically insulating material 206 and the electrically insulating film 210. The electrically insulating film 210 comprises a flexible material that preferably has high dielectric capability and low thermal mass, such as polyimide, polyetheretherketone (PEEK), or polytetrafluoroethylene (PTFE).

[0043] In some embodiments, the electrically insulating film 210 may be a heat shrink film such that the heating element 208 is secured against the coating of electrically insulating material 206. In other words, the electrically insulating film 210 surrounding the exterior of the heating assembly 200 stiffens the heating assembly 200 and ensures that the heating element 208 maintains contact with the coating of electrically insulating material 206. Additionally or alternatively, the heating element 208 may be secured to the coating of electrically insulating material 206 using an adhesive.

[0044] 3, electrically insulating film 210 is shown as completely enveloping heating element 208 and coating of electrically insulating material 206. That is, electrically insulating film 210 extends beyond heating element 208 to the longitudinal edges of the coating of electrically insulating material. However, it will be appreciated that the size and location of electrically insulating film 210 may vary.

[0045] In the illustrated embodiment, the heating element 208 is a free-standing heating element attached to the coating 206 of electrically insulating material. However, in an alternative embodiment, the heating element 208 may be included within a thin film heater (not shown), which includes a flexible backing film on which the heating element 208 is disposed. For example, the heating element may be adhered to the flexible backing film, for example, by a silicone adhesive. In this case, the thin film heater may be wrapped circumferentially around the heating chamber 200 such that the heating element 208 is located adjacent to the coating 206 of electrically insulating material. The flexible backing film is located on the opposite side of the heating element 208 from the coating 206 of electrically insulating material, i.e., the heating element 208 is attached to the inner surface of the flexible backing film relative to the heating chamber 202.

[0046] FIG. 4 shows a flow diagram of a method 300 for manufacturing a heat chamber according to one embodiment of the present invention.

[0047] The method 300 begins in step 302, where a heating chamber 202 is provided having an opening 204 for receiving an aerosol substrate therein. The heating chamber 202 can be manufactured according to the method described in the aforementioned PCT / EP2020 / 074147. In step 304, a coating 206 of an electrically insulating material is applied to the outer surface 203 of the heating chamber 202. That is, the coating 206 of the electrically insulating material is bonded to the outer surface of the heating chamber 202 such that the coating at least partially surrounds, and preferably encircles, the heating chamber 202 circumferentially. The coating may be applied using various coating processes and techniques, such as vapor deposition, chemical and electrochemical techniques, spraying, dipping, or painting. For example, the coating 206 of the electrically insulating material may be applied using plasma spraying, wire arc spraying, cathodic arc, sputtering, or ion beam deposition. The selection of these processes and techniques may depend on the coating material.

[0048] Optionally, in step 306, the coating of electrically insulating material 206 is cured in one or more curing stages, preferably at temperatures above 80°C. In one example, the coating of electrically insulating material may be cured at 95°C for 15 minutes, then at 250°C for 15 minutes, and finally at 250°C for 10 minutes. This particular curing process is particularly applicable to the layer of electrically insulating material 206 comprising silicone, preferably silicone, glass, and ceramic. Those skilled in the art will appreciate that the term "curing," also known as thermal curing or heat curing, refers to a method of hardening or strengthening polymers, such as silicone, by promoting cross-linking of polymer chains. The curing process enhances the ability of the coating of electrically insulating material 206 to resist corrosion and degradation.

[0049] In step 308, the heating element 208 is attached to the coating of electrically insulating material 206. In particular, the heating element 208 is wrapped around the portion of the heating chamber 202 that is covered by the coating of electrically insulating material 206 such that the heating element 208 at least partially surrounds the heating chamber 202, preferably surrounding the heating chamber 202 but not contacting the heating chamber 202 due to the physical barrier provided by the coating of electrically insulating material 206.

[0050] 5, the heating element 208 may be wrapped around the heating chamber 202 using a carrier film 212. That is, the heating element 208 is supported on a surface of the carrier film 212, and the method 300 further includes wrapping the carrier film 212 circumferentially around the heating chamber 202 such that the heating element 208 is positioned opposite the coating of electrically insulating material 206. Once the heating element 208 is properly positioned, the carrier film 212 may be removed.

[0051] In another embodiment, the heating element 208 may be included within a thin film heater that includes the heating element 208 and a flexible backing film on which the heating element 208 is supported. In this case, the method 300 includes wrapping the thin film heater around the heating chamber 202 that has the heating element 208 against the coating 206 of electrically insulating material.

[0052] In step 310, a flexible electrically insulating film 210 is wrapped around the heating chamber 202. The flexible electrically insulating film 210 encases the heating element 208 such that the heating element 208 is sandwiched between the flexible electrically insulating film 210 and the coating 206 of electrically insulating material.

[0053] In one embodiment, the heating element 208 may be supported on a flexible electrically insulating film 210 before being attached to the coating of electrically insulating material 206. In this case, the heating element 206 is wrapped around the heating chamber 202 using the flexible electrically insulating film 210, i.e., steps 308 and 310 are performed simultaneously.

[0054] In some embodiments, flexible electrically insulating film 210 may be a heat shrink film, in which case method 300 further includes applying heat to flexible electrically insulating film 210 such that flexible electrically insulating film 210 shrinks around heating element 208 and secures heating element 208 against coating 206 of electrically insulating material.

Claims

1. 1. A heating assembly for an aerosol generating device, comprising: a metallic tubular heating chamber having an opening for receiving an aerosol substrate; a coating of electrically insulating material at least partially surrounding an exterior surface of the heating chamber, the coating comprising one or more of ceramic, glass, silicone, and carbon; a heating element at least partially surrounding the heating chamber and disposed opposite the coating of electrically insulating material, the coating of electrically insulating material preventing any contact between the heating element and the heating chamber; a flexible electrically insulating film wrapped around the heating chamber on the opposite side of the heating element from the coating of electrically insulating material; Equipped with the flexible electrically insulating film is configured to secure the heating element against the coating of electrically insulating material; The heating assembly wherein the flexible electrically insulating film comprises a heat shrink film.

2. The coating of electrically insulating material is ceramics and glass, Ceramic and silicone, or Glass and Silicone The heating assembly of claim 1 , comprising:

3. The heating assembly of claim 2 , wherein the coating of electrically insulating material comprises ceramic, glass, and silicone.

4. The heating assembly of claim 1 , wherein the coating of electrically insulating material comprises diamond-like carbon (DLC).

5. A heating assembly according to any preceding claim, wherein the heating element is attached to the coating of electrically insulating material using an adhesive.

6. 6. The heating assembly of claim 1, further comprising a thin film heater comprising the heating element and a flexible backing film on which the heating element is supported, the thin film heater being wrapped around the heating chamber with the heating element facing the coating of electrically insulating material.

7. A heating assembly according to any preceding claim, wherein the coating of electrically insulating material surrounds the outer surface of the heating chamber and the heating element surrounds the heating chamber.

8. The heating assembly of any preceding claim, wherein the heating element comprises a resistive metal track.

9. A heating assembly according to any preceding claim, wherein the coating of electrically insulating material has a thickness of between 0.8 and 20 microns.

10. A heating assembly according to any one of the preceding claims, wherein the coating of electrically insulating material has a dielectric breakdown strength of at least 100 V / mm, preferably at least 1000 V / mm.

11. A heating assembly for an aerosol generating device, comprising: a metallic tubular heating chamber having an opening for receiving an aerosol substrate; a coating of electrically insulating material at least partially surrounding an exterior surface of the heating chamber, the coating comprising one or more of ceramic, glass, silicone, and carbon; a heating element at least partially surrounding the heating chamber and disposed opposite the coating of electrically insulating material, the coating of electrically insulating material preventing any contact between the heating element and the heating chamber; a thin film heater comprising the heating element and a flexible backing film on which the heating element is supported, the thin film heater being wrapped around the heating chamber with the heating element facing the coating of electrically insulating material; A heating assembly comprising:

12. A method for manufacturing a heating assembly according to any one of claims 1 to 11, comprising the steps of: applying the coating of electrically insulating material to the exterior surface of the heating chamber by one of vapor deposition, painting, dipping, or spraying; A method comprising:

13. 13. The method of claim 12, further comprising curing the coating of electrically insulating material at a temperature of at least 80°C.

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