Aerosol-generating device with vacuum insulation

Abstract

An aerosol-generating device (100) is disclosed, comprising: a heat insulator (103) comprising an inner wall (104) and an outer wall (106) separated from each other; a cavity (110) defined within the inner wall, the aerosol-forming substance (10) being receivable in the cavity; and a heater (112) positioned to heat an aerosol-forming substance when the aerosol-forming substance is received in the cavity wherein a reflective coating (124) is disposed on an outer surface (104b) of the inner wall; wherein the reflective coating comprises a first layer and a second layer, the first layer and the second layer comprising different materials configured to reflect radiation of different wavelengths.

Description

Technical Field

[0001] The present invention relates to an aerosol generating device. In particular, the present invention relates to an aerosol generating device having a vacuum insulator. Background Art

[0002] An aerosol generating device can generate an aerosol by heating an aerosol-forming material using one or more heaters. Operating the heaters can be energy-intensive, especially in aerosol generating devices configured to heat tobacco in a heating oven. Such aerosol generating devices may also take several seconds to reach the aerosol generating temperature, which can be inconvenient for the user. Therefore, there is a need for more efficient aerosol generating devices that can generate an aerosol more quickly. Additionally, there is a need to keep the outer surface of the aerosol generating device at a safe and comfortable temperature.

[0003] It is an object of the present invention to address these needs. Summary of the Invention

[0004] According to a first aspect of the present invention, there is provided an aerosol generating device comprising: an insulator comprising an inner wall and an outer wall separated from each other; a cavity defined within the inner wall, in which an aerosol-forming material can be received; and a heater positioned to heat the aerosol-forming material when the aerosol-forming material is received in the cavity, wherein a reflective coating is provided on an outer surface of the inner wall.

[0005] In this way, the reflective coating can inhibit radiative heat transfer from the inner wall to the outer wall, thereby providing a more thermally efficient aerosol generating device. The reduced escape of heat from the cavity enables the cavity to reach the aerosol generating temperature more quickly. The insulator also more effectively insulates the outer surface of the aerosol generating device, thereby reducing the temperature of the outer surface during use. This provides a safer device that is more comfortable to hold.

[0006] Those skilled in the art will understand that the terms "inner" and "outer" as used herein refer to the wall (or wall surface) closest to or farthest from the cavity, respectively.

[0007] Preferably, the inner wall and the outer wall are separated from each other by a vacuum. In this way, the insulator is a vacuum insulator and more effectively isolates the cavity. The use of the reflective coating in conjunction with the vacuum insulator is particularly advantageous because the vacuum insulator is very effective in reducing heat transfer by conduction but less effective in reducing heat transfer by radiation. It is believed that the reflective coating can reduce the amount of heat radiated from the outer surface of the inner wall.

[0008] In other exemplary embodiments, the insulator can comprise any suitable insulating medium, such as air.

[0009] Preferably, a reflective coating is also provided on the inner surface of the outer wall. In this way, the heat radiated from the inner wall can be reflected back towards the inner wall to inhibit the escape of heat from the insulator. This further improves the efficiency of the aerosol generating device and reduces the temperature of the outer surface of the aerosol generating device. Additionally, the reduced escape of heat from the cavity enables the cavity to reach the aerosol generating temperature more quickly.

[0010] Preferably, the heater is provided on the outer surface of the inner wall. In this way, the heater can effectively deliver heat to the cavity through the conduction of the inner wall.

[0011] The heater can be provided between the reflective coating and the inner wall. In this way, the heat radiated from the surface of the heater towards the outer wall in the form of infrared radiation is reflected back towards the inner wall. This further improves the thermal efficiency of the aerosol generating device.

[0012] In some embodiments, the heater is provided on the inner surface of the inner wall. The reflective coating can additionally be provided on the inner surface of the inner wall, and the heater can be provided on the reflective coating of the inner surface of the inner wall.

[0013] In other embodiments, the heater can be any form of heater known in the art that is arranged to heat the aerosol generating material received in the cavity. For example, the heater can include inductively or resistively heated blades or rods positioned in the cavity to heat the aerosol generating material. The blades or rods can be configured to pierce a consumable containing the aerosol generating material. Alternatively, the heater can include an inductive arrangement configured to inductively heat one or more inductive elements or sensors. The inductive elements can be provided around the outer periphery of the cavity. Alternatively, one or more inductive elements can be provided inside a consumable that can be received in the cavity.

[0014] Preferably, the reflective coating includes a reflective paint layer. In one example, a white paint with a high reflectivity can be used. It has been found that by using white paint, the outer surface of the inner wall can be reduced to 151 °C during use. In another example, silver paint can be used.

[0015] Preferably, the reflective coating includes a metal foil layer, such as an aluminum foil layer. Alternatively, silver foil can be used. It has been found that by using silver foil, the outer surface of the inner wall can be reduced to 135 °C during use.

[0016] The reflective coating can also include a vapor-deposited metal layer, such as vapor-deposited silver, gold, or aluminum.

[0017] Preferably, the reflective coating includes a first layer and a second layer. The first layer and the second layer may include different materials. This can provide a more effective way to insulate the outer wall from radiant heat. For example, the first layer and the second layer may include different materials and thus may have reflectivity curves that peak at different wavelengths, such that radiation can be effectively reflected over a wider range of wavelengths.

[0018] Preferably, the first layer includes a reflective paint and the second layer includes a metal foil. This can provide a more effective way to insulate the outer wall from radiant heat. In one example, the paint may be a reflective white paint and the metal foil may be aluminum. It has been found that this particular combination reduces the outer surface of the inner wall to 107 °C during use.

[0019] Preferably, the aerosol generating device is configured to heat an aerosol-forming material comprising tobacco. The heater may be configured to heat the cavity to a temperature below the combustion temperature of the tobacco, and the cavity may be configured to receive a rod-shaped or elongated consumable comprising tobacco. This allows the aerosol generating device to function as a heat-not-burn device.

[0020] In some embodiments, a reflective coating may also be provided on the outer wall. In this way, the efficiency of the heat insulator can be further improved. The reflective coating may be provided on the inner surface or the outer surface of the outer wall. Alternatively, the coating may be provided on both the inner surface and the outer surface of the outer wall.

[0021] According to a second aspect of the present invention, there is provided an aerosol generating device comprising: a heat insulator including an inner wall and an outer wall separated from each other; a cavity defined within the inner wall, in which an aerosol-forming material can be received; and a heater positioned to heat the aerosol-forming material when the aerosol-forming material is received in the cavity, wherein a reflective coating is provided on the outer wall.

[0022] In this way, the heat radiated from the inner wall can be reflected back towards the inner wall to inhibit the escape of heat from the heat insulator. This further improves the efficiency of the aerosol generating device and reduces the temperature of the outer surface of the aerosol generating device. Additionally, the reduced escape of heat from the cavity allows the cavity to reach the aerosol generating temperature more quickly.

[0023] The second aspect of the present invention may include any of the features discussed above with respect to the first aspect of the present invention, such as the heat insulator being a vacuum heat insulator and / or a specific reflective coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0025] Figure 1Shows a cross-sectional schematic view of an aerosol generating device according to an embodiment of the present invention;

[0026] Figure 2 Shows a control schematic view of an aerosol generating device according to an embodiment of the present invention;

[0027] Figure 3 Shows a cross-sectional schematic view of a heating device in use according to an embodiment of the present invention;

[0028] Figure 4 Shows a schematic view of a part of a heating device according to an embodiment of the present invention;

[0029] Figure 5 Shows a plan schematic view of a heating device according to an embodiment of the present invention; and

[0030] Figure 6 Shows a schematic view of a part of a heating device according to an embodiment of the present invention. Detailed Description

[0031] Figure 1 Shows a schematic view of an aerosol generating device 100 according to an embodiment of the present invention.

[0032] The aerosol generating device 100 includes a tubular housing 102 for accommodating and protecting the internal components of the aerosol generating device 100. A vacuum insulator 103 is provided, which includes an inner wall 104, an outer wall 106, and an annular vacuum 108 that separates the inner wall 104 and the outer wall 106 and is enclosed by the inner and outer walls. As further discussed below with reference to Figure 4 and 6 The vacuum insulator 103 includes a reflective coating to improve the heat insulation performance of the vacuum insulator 103. A cavity 110 is defined within the inner wall 104 for receiving the aerosol-forming material. An opening 111 is provided in the housing 102 and is aligned with the cavity 110 to enable a user to insert the aerosol-forming material into the cavity 110. A heater 112 is provided on the inner wall 104 and within the vacuum 108 for heating the aerosol-forming material received in the cavity 110 by conduction through the inner wall 104.

[0033] A controller 114 is provided, which is configured to control the operation of the heater 112. A button 116 is provided on the housing 102 and is electrically connected to the controller 114 to enable a user to initiate aerosol generation. A battery 118 is provided for powering the heater 112, the controller 114, and any other electronic components of the aerosol generating device 100.

[0034] Figure 2Shows a control schematic diagram of the aerosol generating device 100. The controller 114 includes at least one processor 114a and a memory 114b for respectively executing and storing executable instructions 114c for operating components of the aerosol generating device 100. The controller 114 is electrically connected to Figure 2 the components shown therein to receive or send operation signals.

[0035] The housing 102 can include any suitable material known in the art, such as plastic or metal. In other embodiments, the button 116 can be replaced by or used in combination with any other suitable input mechanism, such as a fingerprint sensor or a gesture sensor. The battery 118 can be permanently fixed within the housing 102 and be rechargeable. Alternatively, the battery 118 can be removable. In other embodiments, the aerosol generating device may not be provided with the battery 118, and the user can provide a separate battery pack or a disposable power source.

[0036] As Figure 3 shown, the vacuum insulator 103, the heater 112, and the cavity 110 form a heating device 120. The rod-shaped consumable 10 including the tobacco 12 and the filter 14 is shown inserted into the cavity 110, as would be performed by the user before using the aerosol generating device 100.

[0037] The heater 112 is disposed inside the vacuum 108 at two separate positions on diametrically opposite portions of the inner wall 104. The heater 112 includes resistive traces configured to generate heat when supplied with current, and the traces are disposed on a film substrate serving as an electrical insulating substrate. The film heater is curved to match the curvature of the inner wall 104, thereby achieving good thermal contact with the inner wall 104. In an alternative embodiment, the heater 112 can be any suitable heater configured to heat the consumable 10 within the cavity 110 to generate an aerosol. The heater 112 can be provided as one or more curved heating films or traces extending around the circumference of the inner wall 104. Alternatively, the heater 112 can be provided as one or more heating films or traces spaced around the inner wall.

[0038] The heater 112 is configured to heat the inner wall 104 by conduction to raise the air temperature in the cavity 110 to the aerosol generation temperature. The consumable 10 may have a circumference that substantially matches the circumference of the cavity 110 such that the consumable 10 contacts the inner wall 104 when it is placed by a user into the cavity 110. The heater 112 heats the contents of the cavity 110 to a temperature sufficient to generate an aerosol from the tobacco 12 within the consumable 10. The heater 112 may be configured to heat the contents of the cavity 110 to a temperature below the combustion temperature of the tobacco 12, such that the aerosol generating device 100 can function as a so-called "heat-not-burn" device.

[0039] In other embodiments, the cavity 110 and the heater 112 may be configured to receive and heat other forms of consumables known in the art, respectively. For example, the heater 112 may include an inductively heatable susceptor material configured to generate heat under the influence of an electromagnetic field. Such an electromagnetic field may be generated by an inductor unit disposed at a suitable location within the aerosol generating device 100. Alternatively, the susceptor material may be permanently located within the cavity 110, or may be disposed within the consumable 10. The heater 112 may also take the form of a resistively or inductively heatable rod or blade positioned within the cavity 110 to pierce the consumable 10.

[0040] Figure 1 The vacuum insulator 103 has an annular cylindrical shape with a circular cross-section. The vacuum insulator 103 is hollow and encloses a vacuum 108 between a curved inner wall 104, a curved outer wall 106, and a generally flat surface 122a - 122c that seals the vacuum 108 within the inner wall 104 and the outer wall 106. The flat surface 122a connects the inner wall 104 to the outer wall 106, while the flat surfaces 122b, 122c seal the inner wall 104 and the outer wall 106, respectively.

[0041] In other embodiments, the vacuum insulator 103 may have other shapes. For example, the vacuum insulator 103 may have a square or polygonal cross-section, or any other suitable cross-sectional shape. Figure 1 and Figure 3 The vacuum insulator 103 shown in has a cup shape with an open end and a closed end; however, the vacuum insulator 103 may also have a tubular shape with two open ends. In another example, the outer wall 106 may be directly connected to the inner wall 104 without a connecting flat surface 122a (as shown in Figure 3 ). The vacuum insulator 103 may be mechanically attached to the housing 102 by one or more mechanical connectors (not shown). The vacuum insulator 103 may include stainless steel, a heat-resistant plastic such as PEEK, or any other suitable material.

[0042] The heater 112, the inner wall 104, and the flat surface 122b jointly heat the consumable 10 by conduction, and can thus also be collectively referred to as the "heating cup". The outer wall 106 and the flat surface 122c enclose the vacuum 108 around the heating cup, and can thus also be referred to as the "outer shell" or "vacuum chamber" of the heating cup. The heating cup and the outer shell can include different materials. For example, the inner wall 104 and the flat surface 122b can include a metal, such as stainless steel, while the outer wall 106 and the flat surface 122c can include a heat insulator, such as heat-resistant glass. The inner wall 104 and the outer wall 106 can include any suitable materials known in the art. The flat surface 122a can be integral with the heating cup or the outer shell, or can be provided as a separate component connected to the inner wall 104 and the outer wall 106.

[0043] In other example embodiments, the vacuum insulator 103 can be replaced with other types of insulators. In one example, the insulator can be provided to include an inner wall and an outer wall, containing an insulating medium, such as air, aerogel, and various foam or fiber materials, instead of the vacuum 108.

[0044] Now will refer to Figure 1 An example use of the aerosol generating device 100 will be described. In use, the user can insert the consumable 10 into the cavity 110 through the opening 111. The inner wall 104 holds the consumable 10 in place within the cavity 110 by friction. When the user is ready to start vaporizing, the user can press the button 116, which in turn triggers the controller 114 to turn on the heater 112. The heater 112 heats the contents of the cavity 110 (including the consumable 10), while the vacuum 108 within the vacuum insulator 103 inhibits the escape of heat from the cavity 110. Thus, the heating device 120 forms an oven in which the tobacco 12 within the consumable 10 can be heated to a desired temperature. The controller 114 can be configured to instruct the heater 112 to heat the tobacco 12 to a temperature below the combustion temperature of the tobacco. When the tobacco 12 is heated, an aerosol is generated inside the cavity 110. The user can draw air through the filter 14 to create an air flow through the consumable 10 to inhale the aerosol, which brings the aerosol to the user.

[0045] Figure 4 A cross-sectional portion of the heating device 120 according to an embodiment of the present invention is shown. The inner wall 104 includes an inner surface 104a facing the cavity 110 and an outer surface 104b facing the vacuum 108. Similarly, the outer wall 106 includes an inner surface 106a facing the vacuum 108 and an outer surface 106b facing the housing 102. Figure 5 A plan view of the heating device 120 is shown to show the different surfaces of the inner wall 104 and the outer wall 106 from different angles.

[0046] During use, the heater 112 heats the inner wall 104 to a temperature typically above 100 °C. The consumable 10 contacts the inner surface 104a, and thus the consumable 10 is heated by conduction. The inner surface 104a also emits radiation or "radiant heat", which can be absorbed by the consumable 10 to further heat the consumable 10. However, the outer surface 104b of the inner wall 104 may also undesirably emit radiant heat towards the outer wall 106. This radiation can be absorbed by the outer wall 106 and subsequently lost from the vacuum insulator 103 through conduction or radiation processes. As Figure 4 shown, the present invention provides a first reflective coating 124 on the outer surface 104b so as to minimize the heat loss from the vacuum insulator 103 in this way.

[0047] The first reflective coating 124 can reflect the radiation received from the outer surface 104b. Additionally, the reflective coating 124 can inhibit the radiation from exiting the outer surface 104b. This provides a more efficient insulator for the aerosol generating device 100. Additionally, the consumable 10 reaches the aerosol generating temperature faster because less heat can escape from the cavity 110.

[0048] In Figures 1 to 5 an embodiment, the first reflective coating 124 is provided on all of the inner wall 104 and the flat surface 122b (i.e., on the entire "heating cup"). In other embodiments, the first reflective coating 124 can be provided only on a portion of the inner wall 104, such as only on the portions of the inner wall 104 and the flat surface 122b that are exposed to the vacuum 108. In Figure 6 a further embodiment shown, the first reflective coating 124 can be provided on the heater 112 such that the heater 112 is enclosed between the first reflective coating 124 and the inner wall 104. This can inhibit the radiation from exiting the heater 112 towards the inner surface 106a of the outer wall 106, thereby further improving the efficiency and reducing the heating time of the consumable 10.

[0049] A second reflective coating 126 is also provided on the inner surface 106a of the outer wall 106. The second reflective coating 126 reflects the radiation that reaches the outer wall 106 (despite the first reflective coating 124) back towards the cavity 110. This further improves the efficiency and reduces the heating time of the consumable 10.

[0050] The second reflective coating 126 can be similarly provided on some or all of the inner wall 106 and the flat surface 122c (i.e., the "outer shell"). The second reflective coating 126 can include the same or different materials as the first reflective coating 124. In other embodiments, only one of the first reflective coating 124 and the second reflective coating 126 is provided.

[0051] The first reflective coating 124 and the second reflective coating 126 can include any suitable material. Some example materials that can be used include: coatings, such as white, silver coatings or other metallic coatings; metals, such as metal foils including silver, aluminum, and gold; vapor-deposited metal layers, such as vapor-deposited silver, aluminum, or gold; or glazes, such as Heraeus overglaze. The metal layer can be provided with an oxide protection layer; however, this may not be required in the vacuum insulator 103. The reflectivity properties of gold, silver, and aluminum for different wavelengths are shown in Table 1 below. When including the corresponding materials, the first reflective coating 124 and / or the second reflective coating 126 can at least have the reflectivity levels shown in Table 1.

[0052]

[0053] Table 1: Reflectivity properties of gold, silver, and aluminum at different wavelengths.

[0054] The first reflective coating 124 and / or the second reflective coating 126 can also include a first layer having a first material and a second layer having a second material. In one example, the first reflective coating 124 can include a white coating applied to the outer surface 104b and an aluminum foil wrapped around the outer surface 104b above or below the heater 112. In other examples, the first reflective coating 124 or the second reflective coating 126 can use any combination of two or more of the materials discussed above.

[0055] Table 2 shows the temperature of the outer surface 104b when the heater is turned on for different material selections of the first reflective coating 124. As shown, it was found that the combination of the white coating and the aluminum foil is particularly effective in reducing the temperature of the outer surface 104b (and thus also reducing the radiative transfer of heat to the outer wall 106).

[0056] Coating Inner wall outer surface temperature (°C) Black paint 163 White paint 151 Heraeus glaze 147 Silver 135 White paint and aluminum foil 107

[0057] Table 2: Temperatures of the outer surfaces of the inner walls obtained when the heater is turned on for different coatings.

[0058] In some embodiments, a reflective coating can also be provided on the outer surface 106b of the outer wall 106 to further insulate the cavity 110. The outer surface 106b can be coated with any one of the materials discussed above with respect to the first reflective coating 124 or the second reflective coating 126.

[0059] In a further embodiment, in addition to the outer surface 104b, a reflective coating can also be provided on the inner surface 104a. In this case, the heater 112 is positioned on the inner surface 104a, on the reflective coating of the inner surface 104a, rather than on the outer surface 104b within the vacuum 108.

Claims

1. An aerosol generating device, comprising: An insulator, the insulator including an inner wall and an outer wall separated from each other; A cavity defined within the inner wall, an aerosol-forming substance being receivable within the cavity; And A heater positioned to heat the aerosol-forming substance when the aerosol-forming substance is received within the cavity, wherein a reflective coating is provided on an outer surface of the inner wall; Wherein the reflective coating includes a first layer and a second layer, the first layer and the second layer including different materials configured to reflect radiation of different wavelengths.

2. The aerosol generating device according to claim 1, wherein, The inner wall and the outer wall are separated from each other by a vacuum.

3. The aerosol generating device according to claim 1 or claim 2, wherein, The reflective coating is provided on an inner surface of the outer wall.

4. The aerosol generating device according to any one of the preceding claims, wherein, The heater is provided on the outer surface of the inner wall.

5. The aerosol generating device according to claim 4, wherein, The heater is provided between the reflective coating and the inner wall.

6. The aerosol generating device according to any one of claims 1 to 3, wherein, The heater is provided on an inner surface of the inner wall.

7. The aerosol generating device according to claim 6, wherein, The reflective coating is also provided on an inner surface of the inner wall, and the heater is provided on the reflective coating.

8. The aerosol generating device according to any one of the preceding claims, wherein, The reflective coating includes a reflective paint layer.

9. The aerosol generating device according to any one of the preceding claims, wherein, The reflective coating includes a metal foil layer, such as an aluminum foil layer.

10. The aerosol generating device according to any one of the preceding claims, wherein, The reflective coating is provided on the outer wall.

11. The aerosol generating device according to any one of the preceding claims, the aerosol generating device being configured to heat an aerosol-forming substance, the aerosol-forming substance including tobacco.

12. An aerosol generating device, comprising: An insulator, the insulator including an inner wall and an outer wall separated from each other; A cavity defined within the inner wall, an aerosol-forming substance being receivable within the cavity; And A heater positioned to heat the aerosol-forming substance when the aerosol-forming substance is received within the cavity, wherein a reflective coating is provided on the outer wall; Wherein the reflective coating includes a first layer and a second layer, the first layer and the second layer including different materials configured to reflect radiation of different wavelengths.

Images