Aerosol-generating device with vacuum insulation

Abstract

An aerosol-generating device (100) is disclosed, and the aerosol-generating device comprises: a vacuum insulation (110) comprising an inner wall (112) and an outer wall (114), a vacuum (116) being enclosed between the inner wall and the outer wall; a cavity (106) in which an aerosol-forming 5 substance (12) may be received, the cavity being positioned adjacent to an inner wall of the vacuum insulation and having an opening (104) to enable a user to insert the aerosol-forming substance into the cavity; a heater (108) disposed in thermal contact with the inner wall, configured to heat an aerosol-forming substance received in the cavity by thermal conduction to generate an aerosol; and a thermal bridge (118) 10 disposed between the inner wall and the outer wall to allow a path for heat conduction, where the thermal bridge is positioned in a vacuum between a first end (120) of the vacuum insulation closest to the opening and the heater to enable heat to be transferred from the inner wall to the outer wall by conduction.

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 may include a heater and a vacuum insulator for thermally insulating the heater from the external environment. Heat may be lost from an opening in the vacuum insulator, thereby reducing the thermal efficiency of the device and posing a potential safety risk to the user if the opening reaches a sufficiently high temperature. Therefore, there is a need for a safer and more efficient aerosol generating device. There is also a need for a solution that is compatible with existing designs of aerosol generating devices, and a more convenient and compact aerosol generating device.

[0003] The present invention aims to address these needs. Summary of the invention

[0004] According to one aspect of the present invention, an aerosol generating device is provided, which is configured to generate an aerosol for inhalation by a user, and the aerosol generating device includes: a vacuum insulator, which includes an inner wall and an outer wall, and a vacuum is enclosed between the inner wall and the outer wall; a cavity, in which an aerosol-forming substance can be received, the cavity is positioned adjacent to the inner wall of the vacuum insulator and has an opening so that a user can insert the aerosol-forming substance into the cavity; a heater, which is arranged to be in thermal contact with the inner wall and is configured to heat the aerosol-forming substance received in the cavity by heat conduction to generate an aerosol; and a heat bridge, which is arranged between the inner wall and the outer wall to allow a path for heat conduction, wherein the heat bridge is positioned in the vacuum between the first end of the vacuum insulator closest to the opening and the heater, so that heat can be transferred from the inner wall to the outer wall by conduction.

[0005] In an aerosol generating device with a vacuum insulator, a relatively large amount of heat from the heater can flow along the inner wall towards the opening into which the consumable can be inserted. This may cause the end of the vacuum insulator closest to the opening to reach a high temperature. It has been found that this enables heat to leak from the aerosol generating device. The present invention employs a thermal bridge between the inner wall and the outer wall of the vacuum insulator disposed in a vacuum between the heater and the first end. In this way, heat can flow along the inner wall to the outer wall using the thermal bridge, thereby allowing some of the heat to flow away from the first end. This can reduce the maximum operating temperature of the first end in use, thereby improving the efficiency of the device. This can also improve the safety of the device by reducing the temperature of components that the user may accidentally touch. Providing a thermal bridge inside the vacuum insulator also beneficially avoids changing the external shape or size of the vacuum insulator, making the solution of the present invention compatible with existing designs of aerosol generating devices.

[0006] The thermal bridge is arranged "in the vacuum", ie inside the vacuum insulation between the inner and outer walls enclosing the vacuum. The thermal bridge may be completely or substantially surrounded by the vacuum.

[0007] The thermal bridge may include any suitable connection structure that enables heat to flow from the inner wall to the outer wall. In one example, the thermal bridge may include one or more rigid columns or ribs. In another example, the thermal bridge may include one or more heat conducting wires.

[0008] Preferably, the thermal bridge is positioned longitudinally on the inner wall between the heater and the first end of the vacuum insulator. In other words, the thermal bridge is disposed at a circumferential position on the inner wall that is approximately "above" the heater, or in line with the heater, toward the first end. In this way, the thermal bridge can be positioned close to the most direct path along the inner wall from the heater to the first end, or along the most direct path along the inner wall from the heater to the first end, thereby achieving a more effective redirection of heat toward the outer wall. In other embodiments, the thermal bridge can be disposed at other circumferential positions on the inner wall.

[0009] Preferably, the thermal bridge is disposed on the inner wall at a position spaced 1 mm or more from the heater towards the first end. In this way, the thermal bridge can avoid allowing excessive heat to flow to the outer wall, which can reduce the thermal efficiency of the device. The thermal bridge can be spaced 1 mm, 1.5 mm, 2 mm, 5 mm or any other suitable distance from the heater.

[0010] Preferably, the position of the thermal bridge on the inner wall is selected to maintain the outer surface of the first end of the aerosol generating device adjacent to the vacuum insulator at 48°C or below when the heater is in use. In this way, the outer surface of the aerosol generating device adjacent to the first end can be maintained at a safe and thermally effective temperature. The outer surface can be a shell or housing configured to accommodate and protect the components of the aerosol generating device. The thermal bridge can be positioned based on testing of different spacings from the heater when the heater is turned on and in use. The specific positioning on the inner wall can depend on the specific design and operating parameters of the aerosol generating device. Those skilled in the art will understand that the positioning, length, thickness, material and / or structure of the thermal bridge can be adjusted in various ways to maintain a temperature of 48°C when the heater is in use.

[0011] Preferably, the heater is arranged in the vacuum, on the inner wall. In this way, the heater can be more effectively insulated from the external environment. Alternatively, the heater can be arranged outside the vacuum on the inner wall (e.g., on the inner surface of the inner wall).

[0012] Preferably, the thermal bridge comprises a metal such as stainless steel. In other embodiments, the thermal bridge may comprise any other suitable thermally conductive material, such as copper or ceramic.

[0013] Preferably, the thermal bridge provides structural support for the inner and outer walls. Thus, the thermal bridge may comprise a rigid structure. In this way, the vacuum insulator may be made more robust. This additional robustness may allow the inner and outer walls to be made thinner, which has been shown to improve heating efficiency and the speed at which the aerosol generating material reaches an optimum temperature. Thinner inner and outer walls also make the vacuum insulator more compact, which improves the convenience of the device for the user.

[0014] In some embodiments, the thermal bridge comprises one or more ribs disposed at circumferentially spaced locations on the inner wall. For example, the thermal bridge may comprise two, three, four or more ribs or posts evenly or irregularly spaced around the inner wall.

[0015] In some embodiments, the thermal bridge is configured to separate the first portion of the vacuum from the second portion of the vacuum. For example, the thermal bridge may include a surface with vacuum positioned near two faces of the surface such that the surface completely isolates the two portions of the vacuum from each other. In this way, thermal isolation of the first end may be improved. In one example, the thermal bridge may include an annular connection surface.

[0016] Preferably, the aerosol generating device further comprises a plurality of heaters and a plurality of heat bridges, wherein each heat bridge is longitudinally positioned between a corresponding heater and the first end of the vacuum insulator. In this way, a more uniform heating of the aerosol forming substance may be achieved when the maximum temperature of the first end is reduced using a plurality of heat bridges in use.

[0017] Preferably, the vacuum insulator comprises a closed second end opposite the first end. The closed second end may be more effective in isolating the remaining components of the aerosol generating device from the heater than the open first end. Providing a thermal bridge between the first end and the heater in this case may most effectively locate the thermal bridge. In one example, the inner wall and the outer wall may each have a substantially U-shaped cross-section joined together only at the first end.

[0018] In other embodiments, the first end and the second end may both be open such that the vacuum insulator is substantially tubular. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0020] Figure 1 is a schematic cross-sectional view of an aerosol generating device in an embodiment of the present invention;

[0021] Figure 2 is a plan view of a vacuum insulator in an embodiment of the present invention;

[0022] Figure 3 is a schematic cross-sectional view of a portion of a vacuum insulator in an embodiment of the present invention; and

[0023] Figure 4 is a schematic diagram of a portion of a vacuum insulator in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] Figure 1 1 is a schematic cross-sectional view of an aerosol generating device in an embodiment of the present invention. An aerosol generating device 100 is provided, and the aerosol generating device includes a housing 102 for accommodating the internal components of the aerosol generating device 100. The housing 102 includes an opening 104 leading to a cavity 106, which is configured to receive a consumable 10. The consumable 10 includes tobacco 12 and a filter 14, both of which can be held together by a tipping wrapper 16. A vacuum insulator 110 is provided, and the vacuum insulator has an annular cylindrical shape with an inner wall 112 and an outer wall 114, and a vacuum 116 is enclosed between the inner wall and the outer wall. A heater 108 is disposed in the vacuum 116, on the outer surface of the inner wall 114, and is configured to provide heating to the consumable when the consumable 10 is received in the cavity 106 to generate an aerosol. A thermal bridge 118 is provided in the vacuum 116 between the heater 108 and a first end 120 of the vacuum insulator 110 closest to the opening 104. The thermal bridge 118 provides a path for heat to flow from the inner wall 112 to the outer wall 114 to reduce the temperature of the first end 120 of the vacuum insulator 110 in use.

[0025] The aerosol generating device 100 also includes a controller (not shown) for controlling the operation of the aerosol generating device 100, a button (not shown) for receiving instructions from a user, an air inlet (not shown) in fluid communication with the cavity 106, and a battery (not shown) for powering the aerosol generating device 100. The controller and the battery are in electronic communication with the button and the heater 108 via wires (not shown).

[0026] The housing 102 may include any suitable material known in the art, such as metal or plastic. Figure 1 As shown, the aerosol generating device 100, the vacuum insulator 110 and the cavity 106 may be elongated in the longitudinal direction.

[0027] exist Figure 1In an embodiment, the heater 108 is disposed inside the vacuum 116 at two separated positions on circumferentially opposite portions of the inner wall 112. The heater 108 includes two resistive film heaters configured to generate heat when provided with an electric current. The film heater is curved to match the curvature of the inner wall 112, thereby achieving good thermal contact with the inner wall 112. In alternative embodiments, the heater 108 may be provided as any suitable heater capable of heating the consumables 10 within the cavity 106 to produce an aerosol. In other examples, the heater 108 may be provided outside the vacuum 116, such as at the periphery of the cavity 106. The heater 108 may be provided as one or more curved heating films or tracks extending around the circumference of the inner wall 112. Alternatively, the heater 108 may be provided as one or more heating films or tracks provided at spaced positions around the inner wall.

[0028] The heater 108 is configured to heat the inner wall 112 by conduction to raise the temperature of the air in the cavity 106 to an aerosol generation temperature. The consumable 10 may have a circumference that substantially matches the circumference of the cavity 106, so that the consumable 10 is in contact with the inner wall 112 when it is placed into the cavity 106 by a user. The heater 108 heats the contents of the cavity 106 to a temperature sufficient to generate an aerosol using the tobacco 12 inside the consumable 10. The heater 108 may be configured to heat the contents of the cavity 106 to a temperature below the combustion temperature of the tobacco 12, thereby enabling the aerosol-generating device 100 to function as a so-called "heat-not-burn" aerosol-generating device.

[0029] In other embodiments, the cavity 106 and the heater 108 may be configured to receive and heat other forms of consumables known in the art, respectively. For example, the cavity 106 may be configured to receive a consumable cartridge comprising a reservoir containing an aerosol-generating fluid, and the heater 108 may be configured to provide heating to the consumable when the consumable is received in the cavity 106. In this case, the vacuum insulator 110 and the cavity 106 may be appropriately shaped so that the cartridge can be received in the cavity 106 so as to be heated by the heater 108 and insulated by the vacuum insulator 110.

[0030] Figure 1 The vacuum insulator 110 has a circular cylindrical shape with a circular cross section. The vacuum insulator 110 is hollow and encloses a vacuum 116 between a curved inner wall 112, a curved outer wall 114, and two flat surfaces 115 connecting the inner wall 112 and the inner wall 114. In other embodiments, the vacuum insulator 110 may have other shapes. For example, the vacuum insulator 110 may have a square or polygonal cross section, or any other suitable cross-sectional shape. Figure 1The vacuum insulator 110 has a tubular shape with two open ends; however, the vacuum insulator 110 may also have a cup-shaped cross-section with only one open end. In another example, the outer wall 114 may be directly joined to the inner wall 112 without a connecting flat surface 115 at the first end 120 of the vacuum insulator 110, such as Figure 3 The vacuum insulator 110 may be mechanically attached to the housing 102 via one or more mechanical couplings (not shown). The vacuum insulator 110 may include stainless steel, a heat-resistant plastic such as PEEK, or any other suitable material.

[0031] The controller may be housed within the housing 102 and include a memory and a processor for storing and executing instructions to control various operations of the aerosol generating device 100. An air inlet may be provided as an opening in the housing 102 towards the second end 122 of the aerosol generating device 100 to enable a user to draw air through the cavity 106 via the filter 14. A button may also be provided on an outer surface of the housing 102 for receiving input from a user. Alternatively, any other input mechanism such as a fingerprint or airflow sensor may be provided for receiving input from a user.

[0032] exist Figures 1 to 3 In the embodiment of FIG. 1 , the thermal bridge 118 includes two straight rigid ribs or posts connecting the inner wall 112 and the outer wall 114 , each rib or post being positioned directly between a corresponding heating plate of the heater 108 and the first end 120 of the vacuum insulator 110 . Figure 2 , a plan view of the vacuum insulator 110 viewed from above the first end 120 is shown, showing two ribs with relative circumferential positions on the inner wall 112. In other embodiments, the ribs may be positioned at other circumferential positions on the inner wall 112. The rigidity of the ribs may provide structural support to the inner wall 112 and the outer wall 114.

[0033] The thermal bridge 118 may include any suitable material for enabling heat to flow from the inner wall 112 to the outer wall 114, such as stainless steel, copper, other metal or non-metal materials. In other embodiments of the present invention, additional ribs or fewer ribs may be provided. The ribs or posts may be placed at equally spaced locations or at irregular locations on the inner wall 112. The thermal bridge 118 may also include other types of structures suitable for achieving heat flow by conduction from the inner wall 112 to the outer wall 114.

[0034] Now refer to Figure 1An example use of the aerosol generating device 100 is described. In use, a user can insert the consumable 10 into the cavity 106 through the opening 104. The inner wall 112 holds the consumable 10 in place within the cavity 106 by friction. This contact between the inner wall 112 and the consumable 10 also increases the efficiency of heat being delivered to the tobacco 12 within the consumable 10. When the user is ready to start vaporization, the user can press a button, which in turn triggers the controller to turn on the heater 108. The heater 108 provides heating to the contents of the cavity 106 (including the consumable 10), while the vacuum 116 within the vacuum insulator 110 inhibits heat from escaping from the cavity 106 by conduction and convection. Therefore, the cavity 106, the heater 108 and the vacuum insulator 110 form an oven in which the tobacco 12 within the consumable 10 can be heated to a desired temperature. The controller can be configured to instruct the heater 108 to heat the tobacco 12 to a temperature below the combustion temperature of the tobacco. As the tobacco 12 is heated, an aerosol is generated inside the cavity 106. The user can inhale the aerosol by drawing air through the air inlet via the filter 14 to generate an air flow through the cavity 106, which carries the aerosol to the user.

[0035] It has been found that in similar known aerosol generating devices, the end of the vacuum insulator closest to the opening to the cavity may undesirably reach a high temperature during use of the aerosol generating device. This end is in contact with the air in the cavity, which is heated by the hot walls of the vacuum insulator. The heated air may be carried out of the cavity by airflow caused by the user or by air passing through the opening. This may carry heat out of the cavity, thereby reducing the efficiency of the aerosol generating device. The high temperature of the exposed end of the vacuum insulator may also heat the outer surface of the housing 102 to a high temperature, which may present a safety risk.

[0036] The aerosol-generating device 100 of the present invention utilizes a thermal bridge 118 to alleviate these problems. Figure 3 A schematic diagram of a portion of a cross section of the vacuum insulator 110 is shown when the heater 108 is in operation. Figure 3 Schematic arrows 1-5 are shown, which indicate the flow of heat caused by conduction in the vacuum insulator 110. When the heater 108 is turned on, a first portion 1 of the heat flows from the heater 108 along the inner wall 112 to the first end 120. The second portion 2 of the heat (which is a portion of the first portion 1) flows along the thermal bridge 118 to the outer wall 114. The remaining portion 3 of the first portion 1 flows to the first end 120. The second portion 2 reaches the outer wall 114 and diffuses across the surface of the outer wall 114, thereby spreading out in different directions as at least a fourth portion 4 and a fifth portion 5 of the heat. As shown, at least the fourth portion 4 is diverted away from the first end 120, thereby reducing the operating temperature of the first end 120 of the vacuum insulator 110 during use.

[0037] For the fifth portion 5 of heat, the conduction path length from the heater 108 to the first end 120 of the vacuum insulator 110 is increased through the thermal bridge 118. Increasing the conduction path length provides more time for heat to be carried away from the first end 120 by radiation or other processes. Thus, increasing the path length of the heat to the first end 120 reduces the amount of heat that reaches the first end 120 by conduction.

[0038] During use, the temperature of the inner wall 112 increases with closer proximity to the heater 108. Since the second portion 2 is part of the first portion 1, the thermal bridge 118 can transfer more or less heat to the outer wall 114 depending on its proximity to the heater 108. It has been found that having a spacing of 1 mm or more from the heater 108 toward the first end 120 advantageously avoids overheating the outer wall 114. The amount of heat transferred from the first end 120 will generally depend on the material and geometry of the vacuum insulator 110 and other factors, such as the operating temperature of the heater 108. For a particular embodiment, a range of spacings can be tested to determine the necessary spacing of the thermal bridge 118 from the heater 108 to maintain the temperature of the outer surface of the vacuum insulator 110 adjacent to the first end 120 equal to or less than 48°C. This is advantageous for both safety and efficiency. The cross-sectional area of ​​the thermal bridge 118 in the longitudinal direction, or the length of the thermal bridge, can also be varied in order to maintain this maximum temperature.

[0039] Figure 4 is a schematic diagram of a portion of a vacuum insulator 110 in an alternative embodiment of the present invention. The dotted lines show the location of the outer wall 114, which has been removed from view so that the inner wall 112 and the thermal bridge 218 can be seen. Figure 4 In the embodiment of the present invention, the thermal bridge 218 is configured as an annular ring, which can also provide structural support for the inner wall 112 and the outer wall 114. The thermal bridge 218 separates the vacuum 116 into the first portion 116a and the second portion 116b, which can improve the thermal isolation of the first end 120. Compared with the thermal bridge 118, due to the larger cross-sectional area of ​​the thermal bridge 218 (taken in the longitudinal direction), the thermal bridge 218 can be configured to transfer a larger amount of heat to the outer wall 114.

[0040] In other embodiments, the thermal bridge 218 may have any other suitable shape and may or may not separate the vacuum 116 into different isolated portions. For example, the thermal bridge 118 may be provided as a plurality of annular arcs at spaced locations around the circumference of the inner wall 112 .

Claims

1. An aerosol generating device, the aerosol generating device being configured to generate an aerosol for inhalation by a user, the aerosol generating device comprising: a vacuum insulator comprising an inner wall and an outer wall, a vacuum being enclosed between the inner wall and the outer wall; a cavity in which an aerosol-forming substance can be received, the cavity being positioned adjacent an inner wall of the vacuum insulator and having an opening to enable a user to insert the aerosol-forming substance into the cavity; a heater disposed in thermal contact with the inner wall and configured to heat an aerosol-forming substance received in the cavity by thermal conduction to generate an aerosol; and a thermal bridge disposed between the inner wall and the outer wall to allow a path for heat conduction, wherein the thermal bridge is positioned in the vacuum between a first end of the vacuum insulator closest to the opening and the heater to enable heat to be transferred from the inner wall to the outer wall by conduction; Wherein, the thermal bridge is longitudinally positioned on the inner wall between the heater and the first end of the vacuum insulator.

2. The aerosol generating device according to claim 1, wherein: The heat bridge is disposed on the inner wall at a position spaced 1 mm or more from the heater toward the first end.

3. The aerosol generating device according to claim 2, wherein: The location of the thermal bridge on the inner wall is selected to maintain an outer surface of the aerosol generating device adjacent the first end of the vacuum insulator at or below 48°C when the heater is in use.

4. An aerosol generating device as claimed in any preceding claim, wherein: The heater is disposed in the vacuum and on the inner wall.

5. An aerosol generating device as claimed in any preceding claim, wherein: The thermal bridge comprises metal such as stainless steel.

6. An aerosol generating device as claimed in any preceding claim, wherein: The thermal bridge provides structural support for the inner wall and the outer wall.

7. An aerosol generating device as claimed in any preceding claim, wherein: The thermal bridge comprises one or more ribs disposed at circumferentially spaced locations on the inner wall.

8. The aerosol generating device according to any one of claims 1 to 6, wherein: The thermal bridge is configured to separate the first portion of the vacuum from the second portion of the vacuum.

9. The aerosol generating device of claim 1, further comprising a plurality of heaters and a plurality of thermal bridges, wherein: Each thermal bridge is longitudinally positioned between a corresponding heater and the first end of the vacuum insulator.

10. An aerosol generating device as claimed in any preceding claim, wherein: The vacuum insulator includes a closed second end opposite the first end.

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