Heating chamber assembly for aerosol generator

Abstract

A heating chamber assembly for an aerosol generator, comprising a heating chamber configured to receive an aerosol generating substrate, and a tape-cast resistance heating layer on the outer surface of the heating chamber, configured to deliver heat to the heating chamber.

Description

Technical Field

[0001] The present invention relates to a heating assembly for an aerosol generating device. The present disclosure is particularly applicable to a portable aerosol generating device that can be self - contained and operate at low temperatures. Such a device can heat a tobacco or other suitable aerosol substrate material by conduction, convection, and / or radiation to generate an aerosol for inhalation, rather than burning it.

Background Art

[0002] (Also known as vaporizers) The popularity and use of risk - reduction devices or risk - modification devices have grown rapidly in recent years as an aid to assist habitual smokers who wish to quit using conventional tobacco products such as cigarettes, cigars, cigarillos, and roll - your - own tobacco. In contrast to burning tobacco in conventional tobacco products, various devices and systems are available for heating or warming aerosolizable substances.

[0003] Generally available risk - reduction devices or risk - modification devices are substrate - heated aerosol generating devices or heat - not - burn (HNB) devices. This type of device generates an aerosol or vapor by heating an aerosol substrate (i.e., a consumable), which typically contains moist leaf tobacco or other suitable aerosolizable material, to a temperature in the range of usually 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 does not contain undesirable combustion by - products. In addition, the aerosol produced by heating tobacco or other aerosolizable materials usually does not contain the burnt or bitter taste that can be unpleasant to the user and can be caused by combustion.

[0004] Thin-film heaters have been used in aerosol generators, typically wrapped around a metal heating chamber. In this configuration, the thin-film heater's function is to heat the heating chamber and the aerosol-generating substrate inside. While these thin-film heaters have enabled more efficient heating of the aerosol-generating substrate, there remains a need for improved heater chamber assemblies for use in aerosol generators, allowing for the use of different materials when forming the heating chamber. [Overview of the project] [Means for solving the problem]

[0005] According to a first aspect of the present invention, a heating chamber assembly for an aerosol generator is provided, the heating chamber assembly comprising a heating chamber configured to receive an aerosol generating substrate, and a tape-cast resistance heating layer on the outer surface of the heating chamber, configured to deliver heat to the heating chamber.

[0006] When describing the configuration of layers and elements constituting a heating chamber assembly, the term "on top" should not be interpreted as being limited to direct contact between two elements. For example, one or more intermediate layers may be provided between the tape-cast resistance heating layer and the outer surface of the heating chamber.

[0007] The present invention also allows for the use of a wider range of materials for other elements of the heating chamber assembly. This increases the flexibility of the method for manufacturing the heating chamber assembly and also enables further advantages discussed below. Specifically, tape casting allows for the formation of the resistance heating layer in a separate step when manufacturing the heating chamber assembly. This layer can then be wrapped around the outer surface of the heating chamber in a conventional manner, improving the throughput when manufacturing the heating chamber assembly.

[0008] In an advantageous embodiment of the present invention, the tape-cast resistance heating layer comprises one or more semiconductors, which preferably comprise one or more ceramic semiconductors such as sintered silicon carbide, liquid-phase sintered silicon carbide, and silicon-impregnated silicon carbide.

[0009] Compared to conventional heaters, ceramic semiconductors can heat to higher temperatures, and are typically suitable for heating up to 900°C. In contrast, conventional heaters are made from materials with a melting point of approximately 280°C. In most embodiments, the aerosol-generating substrate should not be heated above 320°C, which is above the melting point of most conventional heaters; therefore, ceramic semiconductors enable heating of the aerosol-generating substrate to higher temperatures. In addition to enabling heating of the aerosol-generating substrate to higher temperatures, the use of ceramic semiconductors allows for the formation of heating chambers from materials with lower thermal conductivity. For example, heating chambers can be formed using materials such as glass.

[0010] In addition to the tape-cast resistance heating layer, the heating chamber assembly may also include a thermal spray resistance heating layer on the outer surface of the heating chamber, configured to deliver heat to the heating chamber. The tape-cast resistance heating layer can be provided on the thermal spray resistance heating layer or between the thermal spray resistance heating layer and the outer surface of the heating chamber.

[0011] A thermal spray resistance heating layer can be constructed in the same way as a tape-cast resistance heating layer. Therefore, all the features, configurations, and options described for a tape-cast resistance heating layer can be implemented in a thermal spray resistance heating layer, and vice versa.

[0012] The thermal spray resistance heating layer is advantageous in that it exhibits a high degree of compatibility with the outer surface of the heating chamber (or the intermediate layer on which the thermal spray resistance layer is provided), thereby improving the efficiency of heat transfer from the resistance heating layer to the heating chamber and, consequently, to the aerosol-generating substrate accepted into the heating chamber. This allows for the use of a wider range of materials for the heating chamber, whereas conventional methods required the heating chamber to be formed from materials with high thermal conductivity, such as metals.

[0013] Since some materials are particularly suitable for tape casting and others for thermal spraying, this arrangement is especially advantageous when different materials are to be used to create a resistance heating layer. For example, silicon-impregnated silicon carbide is well suited for tape casting.

[0014] Other configurations of the resistance heating layer are also possible, in which the thermal spray resistance heating layer and / or tape-cast resistance heating layer includes one or more electrical insulators. For example, the resistance heating layer may include two or more different materials formed in a pattern, separated by an insulating material.

[0015] As described above, an advantage of the present invention is that it is not necessary to use a thermally conductive material to form the heating chamber; however, it is still desirable to use a thermally conductive material. Such materials, such as metals, are often conductive, and therefore the heating chamber assembly may further include an electrical insulating layer between the tape-cast resistance heating layer and the heating chamber. For example, the electrical insulating layer may include a functionalized silica coating, also known as Dursan®, SiO₂ x :CH y Organic silica coatings such as those mentioned above are particularly advantageous.

[0016] According to a second aspect of the present invention, a method for manufacturing a heating chamber assembly for an aerosol generator, the method comprising providing a heating chamber configured to receive an aerosol generating substrate, tape casting a resistance heating layer configured to deliver heat to the heating chamber, and wrapping the tape-shaped cast resistance heating layer around the outer surface of the heating chamber.

[0017] The expression "wrapped around" should be interpreted in the same sense as the word "on top" as defined above, meaning that one or more intermediate layers may be located between the tape-cast resistance heating layer and the outer surface of the heating chamber. For example, one or more thermal spray resistance heating layers and / or one or more electrical insulating layers may be provided between the tape-cast resistance heating layer and the outer surface of the heating chamber.

[0018] As discussed above in relation to a first aspect of the present invention, the use of tape casting is advantageous because it allows for the production of a resistance heating layer in a step separate from the other steps of the method, and then wrapping it around the outer surface of the heating chamber.

[0019] Some materials are particularly suitable for tape casting, while others are particularly suitable for thermal spraying. Silicon-impregnated silicon carbide is especially well-suited for tape casting, and tape casting is particularly advantageous when different materials are to be used to create the resistance heating layer.

[0020] In addition, the method may include thermal spraying a resistance heating layer onto the outer surface of the heating chamber. As discussed above in relation to a first aspect of the present invention, thermal spraying a resistance heating layer provides a high degree of compatibility between the thermal sprayed resistance heating layer and the outer surface of the heating chamber (or the intermediate layer on which the thermal sprayed resistance layer is provided), thereby improving the efficiency of heat transfer from the resistance heating layer to the heating chamber and, therefore, to the aerosol generating substrate accepted into the heating chamber.

[0021] Among the available methods for thermally spraying a resistive heating layer, atmospheric plasma spraying and high velocity oxygen fuel spraying have been found to provide particularly high levels of conformity between the thermally sprayed resistive heating layer and the outer surface of the heating chamber (or any intermediate layer).

[0022] The method may further include providing an electrical insulation layer between the resistive heating layer and the heating chamber. For example, the electrical insulation layer may include a functionalized silica coating, and organosilica coatings such as SiO x :CH y are particularly advantageous. As discussed above in connection with the first aspect of the present invention, providing an electrical insulation layer allows the use of conductive materials in the heating chamber, which may be advantageous in some cases.

[0023] Providing an electrical insulation layer between the resistive heating layer and the heating chamber preferably includes applying the electrical insulation layer by chemical vapor deposition. Chemical vapor deposition of the electrical insulation layer results in a high level of conformity between the electrical insulation layer and the outer surface of the heating chamber (or the intermediate layer on which the electrical insulation layer is provided). This improves the efficiency of heat transfer across the electrical insulation layer, and thus the efficiency of heat transfer to the aerosol-generating substrate received in the heating chamber.

[0024] Here, embodiments of the present invention will be described by way of example with reference to the drawings.

Brief Description of the Drawings

[0025] [Figure 1] An exemplary aerosol-generating device according to an embodiment of the present invention is shown. [Figure 2] A schematic cross-sectional view of a heating chamber assembly including a resistive heating layer. [Figure 3] A schematic cross-sectional view of a heating chamber assembly including a resistive heating layer and an electrical insulation layer. [Figure 4] A schematic cross-sectional view of another heating chamber assembly including a resistive heating layer and an electrical insulation layer. [Figure 5]This is a flowchart showing the steps for manufacturing a heating chamber assembly according to one embodiment of the present invention. [Modes for carrying out the invention]

[0026] Figure 1 illustrates an aerosol generator 100 according to one embodiment of the present invention. The aerosol generator 100 is illustrated in an assembled configuration with its internal components visible. The aerosol generator 100 is a heated non-combustion device, sometimes also called a tobacco vaporizer, and comprises a heating chamber assembly 200 configured to receive an aerosol generating material, such as a tobacco rod. The heating chamber assembly 200 is operable to heat the aerosol generating material rod rather than burn it, thereby generating vapor or aerosol for the user to inhale. Naturally, those skilled in the art will understand that the aerosol generator 100 depicted in Figure 1 is merely an exemplary aerosol generator according to the present invention. Other types and configurations of tobacco vaporizers, vaporizers, or e-cigarettes may also be provided according to the present invention.

[0027] Figure 2 shows a schematic cross-sectional view of a heating chamber assembly 200 according to one embodiment of the present invention. The heating chamber assembly 200 comprises a heating chamber 202, sometimes called a thermally conductive shell, configured to receive an aerosol generating substrate, sometimes called a consumable. Specifically, the heating chamber 202 is configured to receive an aerosol generating substrate having the shape of a rod. For this purpose, the heating chamber 202 is preferably tubular, i.e., elongated and substantially cylindrical (having a substantially circular or substantially elliptical cross-section), with an opening 204 located at the longitudinal end of the heating chamber 202. The user can insert the aerosol generating substrate through the opening 204 of the heating chamber 202 such that the aerosol generating substrate is located inside the heating chamber 202 and forms an interface with the inner surface 201 of the heating chamber 202. The length of the heating chamber 202 may be configured such that a portion of the aerosol generating substrate protrudes through the opening 204 of the heating chamber 202. Returning to Figure 1, the portion of the aerosol generating substrate then protrudes from the heating chamber assembly 200, allowing it to be received into the user's mouth.

[0028] Those skilled in the art will understand that the heating chamber 202 is not limited to being cylindrical. For example, the heating chamber 202 may be formed as a cubic, conical, hemispherical, or other shaped cavity and configured to accept an aerosol substrate of a complementary shape. Furthermore, in some embodiments, the heating chamber 202 may not completely enclose the aerosol substrate, but instead contact only a limited area of ​​the aerosol substrate.

[0029] For example, the heating chamber 202 may be substantially cylindrical, but may have one or more elongated recessed regions projecting inward to form elongated projections on the inner surface 201 of the heating chamber 202. In another example, the heating chamber 202 may be substantially cylindrical, but may have one or more flat regions extending axially along the heating chamber 202.

[0030] The resistance heating layer 205 surrounds the outer surface 203 of the heating chamber 202. Specifically, the resistance heating layer 205 is adjacent to (i.e., in contact with) the circumferential outer surface 203 of the heating chamber 202. The resistance heating layer 205 is directly bonded to the outer surface 203 of the heating chamber 202; that is, a chemical bond is formed between the resistance heating layer 205 and the heating chamber 202. In Figure 2, the resistance heating layer 205 is depicted as extending along only a portion of the length of the outer surface 203 of the heating chamber 202. However, those skilled in the art will understand that in other embodiments, the resistance heating layer 205 may extend along the entire length of the heating chamber 202. Furthermore, those skilled in the art will understand that the resistance heating layer 205 may only partially surround the outer surface of the heating chamber 202; that is, there may be gaps in the resistance heating layer 205 in the circumferential direction around the heating chamber 202.

[0031] The resistive heating layer 205 is configured to operate as a Joule heater. In other words, the resistive heating layer 205 is configured to release heat in response to the flow of electric current. This physical effect is primarily referred to herein as resistive heating, but may also be called Joule heating or Ohm heating. During use, power may be supplied to the resistive heating layer 205 from a power source such as a battery (not shown) so that the temperature of the resistive heating layer 205 rises and thermal energy is transferred to the heating chamber 202. The aerosol substrate received in the heating chamber 202 is conductively heated by the heating chamber 202 to generate an aerosol for the user to inhale.

[0032] The resistance heating layer 205 is advantageously formed from one or more ceramic semiconductor materials, as these materials are suitable for heating to high temperatures (considered to be 800-1000°C). These ceramic semiconductor materials are typically in single layers and can be applied directly to the cup to form part of the heater assembly in the form of a coating by thermal spraying techniques such as atmospheric plasma spraying and high-speed oxygen fuel spraying, although multiple layers may be used to form the resistance heating layer 205.

[0033] In some embodiments, the resistance heating layer 205 further includes one or more ceramic semiconductor materials that are tape-cast and wrapped around the outer surface 203 of the heating chamber 202.

[0034] The resistive heating layer 205 may also include a nonconductive material provided in one or more coatings. These insulating layers may be provided between the resistive heating layer 205 and the outer surface 203 of the heating chamber 202, or between two or more layers of the ceramic semiconductor material, as will be described in more detail below with reference to Figures 3 and 4. They may also be provided in the same layer as one or more ceramic semiconductor materials.

[0035] For example, one or more ceramic semiconductor materials can be thermally sprayed together with one or more nonconductive materials to create different heater shapes or different heating patterns, or to provide an insulating layer.

[0036] Suitable ceramic semiconductor materials include S-SiC (sintered silicon carbide), LPS-SiC (liquid-phase sintered silicon carbide), and Si-SiC (silicon-impregnated silicon carbide). Si-SiC is particularly suitable for tape casting.

[0037] The outer surface 203 of the heating chamber 202 and the resistance heating layer 205 form a direct bond with each other (i.e., they are chemically bonded at their interface), so there are no gaps or other insulating parts between these components. Advantageously, this limits heat loss during operation and significantly improves the energy efficiency of the heating chamber assembly 200.

[0038] Those skilled in the art will understand that the heating chamber 202 is not intended to function as a resistance heater and therefore should not be subjected to current. For this purpose, the heating chamber 202 is preferably formed from a non-conductive material such as glass, eliminating the need for an additional insulating layer.

[0039] Nevertheless, in some cases, it may be advantageous to form the heating chamber 202 from a conductive material such as metal (for example, steel, stainless steel, or aluminum) in order to improve heat conduction to the aerosol generating substrate. In such cases, since these materials are often conductive, it is advantageous to provide an electrical insulating layer 206.

[0040] Two such embodiments are shown in Figures 3 and 4, in which an electrical insulating layer 206 is provided between the resistance heating layer 205 and the outer surface 203 of the heating chamber 202. In this way, the electrical insulating material coating 206 advantageously prevents short circuits between the heating element 208 and the heating chamber 202 by preventing contact between the conductive material coating 208 and the heating chamber 202, while enabling efficient heat transfer from the conductive material coating 208 to the heating chamber 202. That is, the electrical insulating material coating 206 separates the conductive material coating 208 from the heating chamber 202, ensuring that no current flows from the conductive material coating 208 to the heating chamber 202.

[0041] The electrical insulating layer 206 is depicted as extending along only a portion of the length of the outer surface 203 of the heating chamber 202. However, those skilled in the art will understand that, as with the arrangement of the resistance heating layer 205, in other embodiments the electrical insulating layer 206 may extend along the entire length of the heating chamber 202, or even on the inner surface 201 of the heating chamber 202, as shown in Figure 4. This latter option is particularly advantageous because it simplifies the manufacturing of the heating chamber assembly 200. For example, when depositing the electrical insulating layer 206 on the heating chamber 202 in a chemical vapor deposition process, a masking layer is required in areas of the heating chamber 202 surface where the electrical insulating layer 206 is not present in the final heating chamber assembly 200. This masking layer is then removed, leaving the electrical insulating layer 206 in the areas where the masking layer was not present. By providing the electrical insulating layer 206 over the entire surface of the heating chamber 202, the need to provide a masking layer during the deposition of the electrical insulating layer 206 is eliminated, thereby simplifying the manufacturing of the heating chamber assembly 200. The electrical insulating layer 206 also serves to prevent oxidation of the inner surface 201 and outer surface 203 of the heating chamber 202. Nevertheless, those skilled in the art will understand that the coating 206 of the electrical insulating material may only partially surround the outer surface of the heating chamber 202, that is, there may be gaps in the electrical insulating layer 206 in the circumferential direction around the heating chamber 202. However, the resistance heating layer 205 does not typically extend beyond the electrical insulating layer in either the longitudinal or circumferential direction.

[0042] The outer surface 203 of the heating chamber 202, the electrical insulation layer 206, and the thermal spray resistance heating layer 205 form direct bonds with each other (i.e., they are chemically bonded at their interfaces), so there are no gaps or other insulating portions between these components. Advantageously, this limits heat loss during operation and significantly improves the energy efficiency of the heating assembly 200.

[0043] In the embodiments illustrated in Figures 3 and 4, the resistance heating layer 205 is formed as a continuous surface that completely surrounds the electrical insulation layer 206 in the circumferential direction of the heating chamber. That is, the resistance heating layer 205 covers the electrical insulation layer 206 so that no part of the electrical insulation layer 206 is exposed, at least in the circumferential direction. However, as described above, the resistance heating layer 205 may be patterned, in which case the resistance heating layer will only partially cover the electrical insulation layer 206.

[0044] The electrical insulating layer 206 preferably comprises a material exhibiting a high dielectric breakdown voltage (e.g., about 100 volts or more) and high thermal conductivity. For example, the electrical insulating layer 206 may include ceramic, silicone, glass, silicone oxide, carbon, or a combination thereof. In another example, the coating 206 of the electrical insulating material may include (or optionally consist of) diamond-like carbon (DLC). Other preferred materials include SiO2, also known as Dursan®. x :CH y Examples include functionalized silica such as organic silica. Preferably, the electrical insulating layer 206 has a thickness between 0.1 and 10 microns, more preferably between 0.2 and 3 microns. Such properties improve heat transfer to the aerosol-generating substrate received in the heating chamber 202 while ensuring that the heating chamber 202 remains electrically insulated. Advantageously, the heating and cooling times of the heating chamber 202 are reduced, which can improve the energy efficiency of the heating assembly 200.

[0045] Figure 5 illustrates a method for manufacturing a heating chamber assembly according to one embodiment of the present invention, such as the heating chamber assembly shown in Figures 2, 3, or 4.

[0046] Method 400 begins with step 401, in which a heating chamber configured to receive an aerosol generator is provided. This heating chamber can be provided according to any known method, either in a separate step prior to Method 400 or in a preceding step prior to step 401 as part of Method 400.

[0047] The optional step 402 of providing an electrical insulating layer on the outer surface of the heating chamber may be performed after step 401, either directly on the outer surface of the heating chamber or on an intermediate layer, but in some embodiments this step will be omitted. For example, this step is not necessary when producing a heating chamber assembly without an electrical insulating layer, as shown in Figure 2.

[0048] Next, in step 403, a resistance heating layer is provided on the outer surface of the heating chamber, either directly on the outer surface of the heating chamber or on an intermediate layer such as an electrical insulating layer.

[0049] It will be understood that there may be further steps of method 400 that are not illustrated. For example, there may be one or more further steps of providing one or more resistance heating layers, which may be before step 402, between step 402 and step 403, or after step 403.

[0050] In a preferred embodiment, the heating chamber provided in step 401 is made of a non-conductive material such as glass, a first resistance heating layer is provided before step 402, and a second resistance heating layer is provided in step 403. An electrical insulating layer is also provided in step 402 so as to provide a heating chamber assembly in which the two resistance heating layers are separated by an electrical insulating layer.

[0051] Advantageously, in the embodiments of the present invention described above, at least one resistance heating layer is tape-cast and wrapped around the outer surface of the heating chamber. Further resistance heating layers may also be tape-cast, but alternatively, they may be thermally sprayed onto the outer surface of the heating chamber either directly or on an intermediate layer.

Claims

1. A heating chamber assembly for an aerosol generator, wherein the heating chamber assembly is A heating chamber configured to accept an aerosol generating substrate, A tape-cast resistance heating layer on the outer surface of the heating chamber, wherein the tape-cast resistance heating layer is configured to deliver heat to the heating chamber, A heating chamber assembly comprising:

2. The heating chamber assembly according to claim 1, wherein the tape-cast resistance heating layer comprises one or more semiconductors.

3. The heating chamber assembly according to claim 2, wherein the one or more semiconductors include one or more ceramic semiconductors such as sintered silicon carbide, liquid-phase sintered silicon carbide, and silicon-impregnated silicon carbide.

4. The heating chamber assembly according to any one of claims 1 to 3, further comprising a thermal spray resistance heating layer on the outer surface of the heating chamber, wherein the thermal spray resistance heating layer is configured to deliver heat to the heating chamber.

5. The heating chamber assembly according to any one of claims 1 to 4, wherein the tape-cast resistance heating layer comprises one or more electrical insulators.

6. The heating chamber assembly according to any one of claims 1 to 5, further comprising an electrical insulating layer between the tape-cast resistance heating layer and the heating chamber.

7. The heating chamber assembly according to claim 5, wherein the electrical insulating layer includes a functionalized silica coating such as an organic silica coating.

8. The heating chamber assembly according to any one of claims 1 to 7, wherein the heating chamber is formed from glass.

9. A method for manufacturing a heating chamber assembly for an aerosol generator, wherein the method is: A heating chamber configured to accept an aerosol-generating substrate is provided, The resistive heating layer is tape-cast, wherein the resistive heating layer is configured to deliver heat to the heating chamber. The tape-shaped cast resistance heating layer is wrapped around the outer surface of the heating chamber, Methods that include...

10. The method according to claim 9, further comprising thermal spraying a resistance heating layer onto the outer surface of the heating chamber.

11. The method according to claim 10, wherein the thermal spraying of the resistance heating layer includes atmospheric plasma spraying and / or high-speed oxygen fuel spraying.

12. The method according to any one of claims 9 to 11, further comprising providing an electrical insulating layer between the resistance heating layer and the heating chamber.

13. The method according to claim 12, wherein providing an electrical insulating layer between the resistance heating layer and the heating chamber includes applying the electrical insulating layer by chemical vapor deposition.

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