Heater assembly having heater mount
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- PHILIP MORRIS PRODUCTS SA
- Filing Date
- 2023-05-15
- Publication Date
- 2026-05-22
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a heater assembly for an aerosol generating device.The present invention further relates to an aerosol generating device.The present invention further relates to an aerosol generating system comprising an aerosol generating device and an aerosol forming article. [Background technology]
[0002] It is known to provide an aerosol-generating device for generating an inhalable vapour. Such a device may heat an aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate volatilise without burning the aerosol-forming substrate. The aerosol-forming substrate may be provided as part of an aerosol-generating article. The aerosol-generating article may have a rod shape for insertion of the aerosol-generating article into a cavity (such as a heating chamber) of the aerosol-generating device. A heating element may be arranged in or around the heating chamber to heat the aerosol-forming substrate when the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device.
[0003] The heating chamber may be disposed within the housing of the aerosol generating device to form part of the airflow path through the aerosol generating device. To attempt to prevent the aerosol from escaping the airflow path into other parts of the aerosol generating device, which may damage the electronics of the device, it is known to provide a seal around the airflow path and between the heating chamber and the housing. The seal may be placed in direct contact with the heating chamber, and as a result is typically formed from a heat-resistant polymer such as silicone or polysiloxane. However, exposing such a polymer seal to the heating temperature of the heating chamber may generate undesirable by-products that may contaminate the aerosol. Furthermore, such heating temperatures may degrade the seal over time.
[0004] An additional problem encountered in sealing the airflow path within the aerosol generating device is manufacturing tolerances. Variations in component dimensions due to manufacturing tolerances can result in poor engagement between components and potential gaps through which the aerosol may leak. Achieving a good sealing engagement between components typically requires tight manufacturing tolerances that may be difficult to achieve with rapid manufacturing processes such as injection molding. Additionally, the device may be accidentally dropped. This may change the position of the heating chamber relative to the housing. The change in position of the heating chamber may lead to the heating chamber no longer being sealingly connected to the housing. Impact loading of the heating chamber due to the aerosol generating device being dropped may further structurally damage the mounting connection of the heating chamber within the housing of the aerosol generating device.
[0005] It would be desirable to provide a heater assembly for an aerosol generating device that has improved sealing of its airflow path. It would be desirable to provide a heater assembly for an aerosol generating device that tolerates manufacturing tolerances. It would be desirable to provide a heater assembly for an aerosol generating device that tolerates manufacturing tolerances while providing improved sealing of its airflow path. It would be desirable to provide a heater assembly for an aerosol generating device that is resistant to impacts, such as those caused by an accidental drop. It would be desirable to provide a heater assembly for an aerosol generating device that has minimal to no direct contact with the seal of the heating chamber. Summary of the Invention
[0006] According to one embodiment of the present invention, there is provided a heater assembly for an aerosol generating device. The heater assembly may comprise a tubular heating chamber for heating an aerosol-forming substrate. The tubular heating chamber may comprise a proximal flared end. The heater assembly may further comprise a heater casing disposed around the heating chamber. The heater casing may comprise a proximal wall. The proximal wall may comprise a circular groove extending proximally from an inner surface of the proximal wall. The circular groove may comprise a chamfered inner wall. The chamfered inner wall and the proximal flared end of the tubular heating chamber may have matching shapes. The proximal flared end of the tubular heating chamber may be mounted within the circular groove of the proximal wall.
[0007] According to one embodiment of the present invention, there is provided a heater assembly for an aerosol generating device. The heater assembly comprises a tubular heating chamber for heating an aerosol-forming substrate. The tubular heating chamber comprises a proximal flared end. The heater assembly further comprises a heater casing disposed around the heating chamber. The heater casing comprises a proximal wall. The proximal wall comprises a circular groove extending proximally from an inner surface of the proximal wall. The circular groove comprises a chamfered inner wall. The chamfered inner wall and the proximal flared end of the tubular heating chamber have matching shapes. The proximal flared end of the tubular heating chamber is mounted within the circular groove of the proximal wall.
[0008] By mounting the proximal flared end of the tubular heating chamber in a circular groove in a heater casing with a chamfered inner wall having a matching shape, improved sealing may be provided. By mounting the proximal flared end of the tubular heating chamber in a circular groove in a heater casing with a chamfered inner wall having a matching shape, a heater assembly may be provided that tolerates manufacturing tolerances. By mounting the proximal flared end of the tubular heating chamber in a circular groove in a heater casing with a chamfered inner wall having a matching shape, a heater assembly may be provided that tolerates manufacturing tolerances while providing improved sealing. By mounting the proximal flared end of the tubular heating chamber in a circular groove in a heater casing with a chamfered inner wall having a matching shape, an impact resistant heater assembly may be provided. By mounting the proximal flared end of the tubular heating chamber in a circular groove in a heater casing with a chamfered inner wall having a matching shape, minimal to zero contact of the heating chamber to the seal may be required. This may reduce or prevent the generation of harmful or potentially harmful components (HPHCs) during heating.
[0009] The proximal wall may be perpendicular to the longitudinal axis of the heater assembly. The proximal flared end may have an inner diameter that increases in a proximal direction. The thickness of the material forming the proximal flared end may be constant. The proximal flared end may be funnel shaped with an increasing diameter in a proximal direction. Both the inner and outer surfaces of the proximal flared end may be inclined at the same angle relative to the longitudinal axis of the heater assembly.
[0010] The proximal flared end of the tubular heating chamber may be press fit into the circular groove of the heater casing. The proximal flared end of the tubular heating chamber may be fixed in the circular groove of the heater casing. The proximal flared end of the tubular heating chamber may be attached to the circular groove of the heater casing.
[0011] The tubular heating chamber may be a hollow cylinder having at least one flared end, preferably a proximal flared end. The tubular heating chamber may be a hollow tube having at least one flared end, preferably a proximal flared end. The tubular heating chamber may have at least one expanding cone end, preferably a proximal expanding cone end. The proximal flared end may have an inner diameter measured in a direction perpendicular to the longitudinal axis of the heater assembly. The tubular heating chamber may have a median inner diameter measured at the center of the tubular heating chamber in a direction perpendicular to the longitudinal axis of the heater assembly. The inner diameter of the proximal flared end may be greater than the median inner diameter of the tubular heating chamber.
[0012] The tubular heating chamber may include a distal flared end. The distal flared end may have a diameter that increases in a distal direction. The distal flared end may be funnel-shaped with a diameter that increases in a distal direction. Both the inner and outer surfaces of the distal flared end may be inclined at the same angle.
[0013] The tubular heating chamber may include a proximal flared end and a distal flared end. The tubular heating chamber may be flared at both ends. The distal flared end and the proximal flared end of the tubular heating chamber may have the same inner diameter. The distal flared end may be equivalent to the proximal flared end. The distal flared end may have the same shape as the proximal flared end. The tubular heating chamber bay may be a hollow cylinder with a flared end. The tubular heating chamber may be a hollow cylinder with an expanding conical end.
[0014] The heater assembly may further comprise a heater mount. The heater casing may comprise a heater mount. The heater mount may be attached to the heater casing. The heater casing may coaxially surround the heater mount. The heater mount may be configured to receive one end of the tubular heating chamber. A flared end of the tubular heating chamber may be mounted within the heater mount. A distal flared end of the tubular heating chamber may be mounted within the heater mount. A distal flared end of the tubular heating chamber may be secured to the heater mount. A distal flared end of the tubular heating chamber may be attached to the heater mount. The heater mount may be disposed upstream of the tubular heating chamber. The heater mount may be tubular.
[0015] The heater casing, the tubular heating chamber, and the heater mount may define an airflow path through the heater assembly. The heater casing, the tubular heating chamber, and the heater mount may enclose an airflow path through the heater assembly. The airflow path may be defined by an airflow channel. The airflow channel may be formed by an inner wall of the heater casing, the tubular heating chamber, and the heater mount. The airflow channel may extend along a longitudinal axis of the heater assembly. The airflow channel may be a straight airflow channel.
[0016] The heater mount may include an additional circular groove at the proximal end extending distally from an inner proximal surface of the heater mount. The inner proximal surface of the heater mount may be perpendicular to the longitudinal axis of the heater assembly. The circular groove of the heater mount may include a chamfered inner wall. The chamfered inner wall of the heater mount may be flared distally. The chamfered inner wall of the heater mount and the distal flared end of the tubular heating chamber may have matching shapes. The distal flared end of the tubular heating chamber may be mounted within the circular groove of the heater mount.
[0017] The circular grooves in both the heater casing and the heater mount may include chamfered inner walls. The tubular heating chamber may include proximal and distal flared ends, both of which may have a shape that matches the chamfered inner walls of the heater casing and the heater mount.
[0018] According to one embodiment of the present invention, there is provided a heater assembly for an aerosol generating device. The heater assembly comprises a tubular heating chamber for heating an aerosol-forming substrate. The tubular heating chamber comprises a proximal flared end and a distal flared end. The heater assembly further comprises a heater casing disposed around the heating chamber. The heater casing comprises a proximal wall. The proximal wall comprises a circular groove extending proximally from an inner surface of the proximal wall. The circular groove comprises a chamfered inner wall. The chamfered inner wall and the proximal flared end of the tubular heating chamber have matching shapes. The proximal flared end of the tubular heating chamber is mounted within the circular groove of the proximal wall. The heater assembly further comprises a heater mount. The heater mount comprises an additional circular groove at a proximal end extending distally from an inner proximal surface of the heater mount. The circular groove of the heater mount comprises a chamfered inner wall. The chamfered inner wall of the heater mount and the distal flared end of the tubular heating chamber have matching shapes. The distal flared end of the tubular heating chamber is mounted within a circular groove in the heater mount.
[0019] The chamfered inner wall may include at least one rib, preferably three ribs. The chamfered inner wall may include two, three, four, five, or six ribs. The chamfered inner wall of the circular groove of the heater casing may include a plurality of ribs, preferably two, three, four, five, or six ribs. The chamfered inner wall of the circular groove of the heater mount may include a plurality of ribs, preferably two, three, four, five, or six ribs, more preferably three ribs. The chamfered inner walls of both the heater casing and the heater mount may each include a plurality of ribs, preferably three ribs.
[0020] At least one chamfered inner wall may include at least one protrusion, preferably three protrusions.
[0021] The chamfered inner wall of the heater casing may be flared in a proximal direction. The chamfered inner wall of the heater mount may be flared in a distal direction. The at least one chamfered inner wall may be flared toward a bottom of the circular groove. A cross section of the at least one circular groove may be a right angle trapezoid.
[0022] The chamfered inner wall of the heater casing and the proximal flared end of the tubular heating chamber may be parallel. The chamfered inner wall and the distal flared end of the heater mount may be parallel. The chamfered inner wall and the flared ends may all be parallel.
[0023] The chamfered inner walls of the heater casing and heater mount, and the proximal and distal flared ends of the tubular heating chamber may have a chamfer angle. The chamfer angle may be measured between the longitudinal axis of the heater assembly and the chamfer of the at least one chamfered inner wall or the at least one flared end. The chamfered inner wall of the heater casing may have approximately the same chamfer angle as the proximal flared end of the tubular heating chamber. The chamfered inner wall of the heater mount may have approximately the same chamfer angle as the distal flared end of the tubular heating chamber. The chamfer angles of the at least one chamfered inner wall and the at least one flared end may all be approximately the same. The chamfer angles of the chamfered inner wall and the flared end may have approximately the same absolute value.
[0024] The proximal flared end of the tubular heating chamber and the chamfered inner wall of the heater casing may have a chamfer angle of 20° to 45°, preferably 25° to 40°, more preferably about 30°. The distal flared end of the tubular heating chamber and the chamfered inner wall of the heater mount may have a chamfer angle of 20° to 45°, preferably 25° to 40°, more preferably about 30°. The flared end of the tubular heating chamber and the chamfered inner wall of the heater casing and heater mount may have a chamfer angle of 20° to 45°, preferably 25° to 40°, more preferably about 30°.
[0025] The proximal flared end, the distal flared end, and the chamfered inner wall of the heater casing and the heater mount may have a length measured along the chamfer. The length of the proximal flared end of the tubular heating chamber and the chamfered inner wall of the heater casing may be 0.5 to 5 millimeters, preferably 0.5 to 3 millimeters, more preferably 0.5 to 2 millimeters, and most preferably about 1 millimeter. The length of the distal flared end of the tubular heating chamber and the chamfered inner wall of the heater mount may be 0.5 to 5 millimeters, preferably 0.5 to 3 millimeters, more preferably 0.5 to 2 millimeters, and most preferably about 1 millimeter. Thereby, a contact area between the tubular heating chamber and the heater casing, and between the tubular heating chamber and the heater mount may be provided, which may be small enough to prevent potential generation of HPHC during heating of the heater assembly.
[0026] The proximal flared end, the distal flared end, and the chamfered inner wall of the heater casing and heater mount may have an axial length measured in a direction along the longitudinal axis of the heater assembly. The axial length may be at least 0.8 millimeters. The axial length may be 4 millimeters or less.
[0027] The proximal flared end, the distal flared end, and the chamfered inner walls of the heater casing and heater mount may have a transverse length measured in a direction perpendicular to the longitudinal axis of the heater assembly. The transverse length may be at least 0.5 millimeters. The transverse length may be 2.5 millimeters or less.
[0028] The flared end and chamfered inner wall dimensions may provide improved impact resistance. The heater assembly may be part of an aerosol generating device. Such a device may be accidentally dropped. Such a drop may expose the device to forces that run along the longitudinal axis of the device and therefore along the heater assembly. The chamfer angle of the flared end of the tubular heating chamber may split the initial impact force running along the longitudinal axis of the heater assembly into two perpendicular smaller forces. The stresses created on the heater assembly by these two smaller forces can be withstood by the heater assembly when the magnitude of the initial force is similar to the stresses created when the device is dropped on a hard surface. To ensure this resistance, the chamfer angle may be between 20° and 45°, preferably between 25° and 40°, more preferably about 30°.
[0029] The heater casing may be radially spaced from the heating chamber and the heater mount to define a hollow air space around the tubular heating chamber and the heater mount, thereby providing thermal insulation for the tubular heating chamber. The heater casing may have an outer diameter measured in a direction perpendicular to a longitudinal axis of the heater assembly. The diameter of the heater casing may be greater than the outer diameter of the tubular heating chamber measured in the same direction. A ratio of the outer diameter of the heater casing to the outer diameter of the tubular heating chamber may be between 2 and 3.5. The heater casing may be a tubular heater casing. The tubular heater casing may be coaxially disposed around the tubular heating chamber.
[0030] The inner diameter of the tubular heating chamber may substantially correspond to or be substantially equal to the outer diameter of the aerosol-generating article. In some embodiments, the inner diameter of the tubular heating chamber may be slightly smaller than the outer diameter of the aerosol-generating article, such that the aerosol-generating article is compressed within the tubular heating chamber. For example, the outer diameter of the aerosol-generating article may be about 7.4 millimeters, and the inner diameter of the tubular heating chamber may be about 7.3 millimeters. The length of the tubular heating chamber may substantially correspond to or be substantially equal to the length of the aerosol-forming substrate provided within the aerosol-generating article.
[0031] The heater casing may comprise a proximal heater casing and a distal heater casing. The proximal heater casing may comprise a proximal wall having a circular groove. The heater casing may be a two-part heater casing. The proximal heater casing may comprise an air outlet. The air outlet may be an opening for receiving an aerosol-generating article. The aerosol may exit the opening through an aerosol-generating article received within the tubular heating chamber. The distal heater casing may comprise an air inlet. The tubular heating chamber may be in fluid communication with the air inlet. The tubular heating chamber may be in fluid communication with the air outlet. The tubular heating chamber may be in fluid communication with both the air inlet and the air outlet to define an airflow path through the heater assembly.
[0032] The proximal heater casing may have an airflow channel. The airflow channel of the proximal heater casing may be in fluid communication with the air inlet. The distal heater casing may have an airflow channel. The airflow channel of the distal heater casing may be in fluid communication with the aerosol outlet. The tubular heating chamber may have an airflow channel. The airflow channel of the tubular heating chamber may pass through a length of the tubular heating chamber. The heater mount may have an airflow channel. The airflow channel of the heater mount may pass through a thickness or length of the heater mount. The airflow channels of each of the proximal heating casing, the distal heater casing, the tubular heating chamber and the heater mount may be in fluid communication with each other to define an airflow path through the heater assembly.
[0033] The proximal heater casing and the distal heater casing may be attached to one another. The proximal and distal heater casings may be attached to one another by a fastener. The proximal and distal heater casings may be attached to one another by a plurality of fasteners. The plurality of fasteners may be symmetrically spaced around the proximal and distal heater casings. The fastener or fasteners may include threaded fasteners, such as screws. The fastener or fasteners may include snap-fit fasteners.
[0034] The proximal heater casing and the distal heater casing may have lengths measured in a direction along a longitudinal axis of the heater assembly. The length of the proximal heater casing may be less than the length of the distal heater casing.
[0035] The proximal heater casing may comprise a proximal portion and a distal portion. The proximal portion and the distal portion may have outer diameters measured in a direction perpendicular to the longitudinal axis of the heater assembly. The outer diameter of the proximal portion may be smaller than the outer diameter of the distal portion. The distal portion may comprise a proximal wall comprising a circular groove. The circular groove may have an outer diameter measured in a direction perpendicular to the longitudinal axis of the heater assembly. The outer diameter of the circular groove may be approximately the same as the outer diameter of the proximal portion of the proximal heater casing.
[0036] The distal heater casing may comprise a proximal portion and a distal portion. The proximal portion and the distal portion may have outer diameters measured perpendicular to the longitudinal axis of the heater assembly. The outer diameter of the proximal portion may be greater than the outer diameter of the distal portion.
[0037] The airflow channel may be defined by the proximal portion of the proximal heater casing, the tubular heater tube, the heater mount, and the distal portion of the distal heater casing.
[0038] The heater mount may comprise a proximal portion and a distal portion. The proximal portion may have a larger diameter than the distal portion measured in a direction perpendicular to the longitudinal axis of the heater assembly. The proximal portion may comprise a circular groove. The distal heater casing may comprise a heater mount. The distal heater casing may be a portion of the distal heater casing. Alternatively, the heater mount may be mounted within the distal heater casing. The heater mount may be connected to the distal heater casing via a snap-fit or threaded engagement. The heater mount may be mounted within a distal opening of the distal heater casing. The proximal portion of the distal heater casing may comprise a distal wall. The distal wall may comprise a distal opening. The distal portion of the heater mount may be at least partially inserted within the distal opening of the distal heater casing.
[0039] The tubular heating chamber may be disposed between the proximal heater casing and the heater mount. The tubular heating chamber may be sandwiched between the proximal heater casing and the heater mount. The tubular heating chamber may be press-fit into the proximal heater casing and the heater mount. The proximal flared end of the tubular heating chamber may be attached to a proximal wall of the proximal heater casing and the distal flared end of the tubular heating chamber may be attached to a proximal portion of the heater mount. The matching shapes of the chamfered inner wall and the flared end may provide a sealed connection when the tubular heating chamber is sandwiched or press-fit between the proximal heater casing and the heater mount.
[0040] When the heater mount is mounted in the distal opening of the distal heater casing, a seal can be disposed between the heater mount and an inner surface of the distal heater casing. When the heater mount is mounted in the distal opening of the distal heater casing, a seal can be disposed between the heater mount and an inner surface of the distal heater casing. The seal can be disposed between a distal end of the proximal portion of the heater mount and a distal wall of the proximal portion of the distal heater casing.
[0041] The seal may be elastic. The seal may be formed from any suitable material. The seal may include an elastic material. The seal may include a polymer. The seal may include an elastic polymer. The seal may include or be formed from any suitable polymer, including but not limited to ethylene propylene diene monomer (EPDM) rubber or silicone. The seal may be an O-ring. The O-ring may have a diameter measured in a direction perpendicular to the longitudinal axis of the heater assembly. The diameter of the O-ring may be about the same as or smaller than the outer diameter of the proximal portion of the heater mount measured in the same direction.
[0042] The seal may be compressed when the heater assembly is assembled.The seal may be compressed between the heater mount and the distal heater casing when the heater assembly is assembled.
[0043] The seal may have a Shore hardness of 30A to 90A, preferably a Shore hardness of 50A to 80A, and more preferably a Shore hardness of about 70A. These values of Shore hardness have been found to be soft enough to accommodate manufacturing tolerances, yet hard enough to provide sufficient force to the heater assembly for sealing of the airflow path and integrity of the heater assembly. Shore hardness may be determined by technical standard ISO 868 Type A.
[0044] The seal may include any suitable shape. The seal may include a shape that matches the shape of the heater mount. The seal may include a shape that matches the shape of one of the proximal or distal heater casings. The seal may include an O-ring. The seal may have any suitable cross-sectional shape in the longitudinal plane of the heater assembly, including, but not limited to, a circular cross-sectional shape, or a cross-sectional shape having two opposing flat surfaces, such as a square or rectangular cross-sectional shape.
[0045] The seal may have an uncompressed thickness or diameter of 0.5 millimeters to 2 millimeters. The seal may have an uncompressed thickness or diameter of about 1 millimeter. These uncompressed thicknesses have been found to be particularly effective in accommodating manufacturing tolerances and providing sealing of the airflow path and integrity of the heater assembly.
[0046] An advantage of mounting the seal between the heater casing and the heater mount, rather than between the heater casing and the tubular heating chamber, is that contact between the seal and the tubular heating chamber is avoided. Furthermore, the seal is advantageously disposed at a gap or distance from the tubular heating chamber. The distance between the tubular heating chamber and the seal means that the seal remains cooler than the tubular heating chamber and does not overheat. Because the seal is not subjected to high thermal stresses, improved sealing of the airflow path through the heater assembly may be achieved.
[0047] The heater assembly of the present disclosure is also less susceptible to manufacturing tolerances because the seals can absorb at least a portion of the manufacturing tolerances to achieve an improved seal. Additionally, the matching shapes of the chamfered inner walls and flared ends can provide proper alignment and retention of the heater casing, tubular heating chamber, and heater mount.
[0048] The proximal heater casing, the distal heater casing, the tubular heating chamber, the heater mount, and the seal may enclose an air space. The proximal heater casing, the distal heater casing, the tubular heating chamber, the heater mount, and the seal may enclose an airtight space. The airtight space may be hollow. Alternatively, or additionally, the airtight space may include an insulating material.
[0049] When the chamfered inner wall includes at least one rib, preferably three ribs, the proximal heater casing, the distal heater casing, the tubular heating chamber, the heater mount, and the seal may surround an air space. When the chamfered inner wall of at least one of the heater casing and the heater mount each includes at least one rib, preferably three ribs, the proximal heater casing, the distal heater casing, the tubular heating chamber, the heater mount, and the seal may surround an air space. The air space may improve the overall heating efficiency of the heater assembly.
[0050] The ribs may be combined with an O-ring to provide an airtight seal. The ribs may be combined with an O-ring to limit the possibility of air leakage from the air space. Alternatively, or additionally, the ribs may be combined with an O-ring to limit the possibility of leakage from the airflow path to the heater casing. The ribs and O-ring may absorb manufacturing tolerances, such that the seal may be less or not at all affected by manufacturing tolerances.
[0051] A heater assembly including a two-piece heater casing, a tubular heating chamber with a flared end mounted within the proximal heater casing, and a heater mount disposed on the seal provides a less complex assembly while tolerating manufacturing tolerances and providing a good seal.
[0052] The tubular heating chamber may comprise a metal. The tubular heating chamber may be made of a metal. The tubular heating chamber may be made of stainless steel.
[0053] One or more of the walls of the heater casing and the heater mount may include a plastic material. One or more of the walls of the heater casing and the heater mount may be made of a plastic material. The plastic material may be polyaryletherketone (PAEK), polyetheretherketone (PEEK), or polyphenylenesulfone (PPSU), and more preferably polyphenylenesulfone (PPSU).
[0054] In one embodiment of the present invention, a heater assembly includes a tubular heating chamber made of metal, a heater casing and heater mount made of a plastic material, and a seal between the heater mount and the heater casing. In addition, the tubular heating chamber includes proximal and distal flared ends that are mounted within the chamfered inner walls of the heater casing and heater mount. Such a heater assembly may reduce contact between the metal tubular heating chamber and the plastic heater casing and the plastic heater mount while providing a sealed connection. Direct contact of the seal with the metal tubular heating chamber is prevented. Thereby, a heater assembly is provided that may reduce or prevent the generation of HPHCs.
[0055] The tubular heating chamber may have an elongated shape. A length measured in a direction along the longitudinal axis of the heater assembly may be greater than a diameter of the tubular heating chamber measured in the same direction. The heating chamber may be an elongated hollow tube.
[0056] The heater assembly may further comprise a heating element. The heating element may be disposed at least partially around the tubular heating chamber. The heating element may comprise one or more conductive tracks on an electrically insulating substrate. The heating element may be flexible. The heating element may be wrapped at least partially around the tubular heating chamber. The heating element may be disposed between the heater casing and the tubular heating chamber.
[0057] Alternatively, the distal heater casing may include a circular groove with a chamfered inner wall, the distal flared end of the tubular heating chamber may be mounted in the circular groove, and the proximal flared end may be mounted in a heater mount that is mounted in the proximal heater casing.
[0058] The present invention further relates to an aerosol generating device comprising a heater assembly as described herein. The aerosol generating device preferably comprises a power supply configured to provide power to the heating element. The power supply preferably comprises a power source. The power source is preferably a battery, such as a lithium ion battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for about six minutes, or a multiple of six minutes. In another example, the power source may have a capacity sufficient to allow a predetermined number of puffs, or discontinuous activation of the heater assembly.
[0059] The power supply may comprise control electronics. The control electronics may comprise a microcontroller. The microcontroller is preferably a programmable microcontroller. The electrical circuit may include further electronic components. The electrical circuit may be configured to regulate the supply of power to the heater assembly. Power may be supplied to the heater assembly continuously after activation of the system or may be supplied intermittently (e.g., between puffs). Power may be supplied to the heater assembly in the form of current pulses.
[0060] The present invention further relates to an aerosol generating system comprising an aerosol generating device and an aerosol generating article. The aerosol generating article may include a substrate portion comprising an aerosol-forming substrate. The aerosol generating article may be configured to be at least partially inserted into a tubular heating chamber.
[0061] The aerosol-generating article may comprise a substrate portion comprising an aerosol-forming substrate. The length of the substrate portion may be equal to or less than the length of the heating element. The length of the substrate portion may be greater than the length of the heating element. The length of the substrate portion may be greater than the length of the heating element but less than the length of the heating chamber. The length of the substrate portion may be equal to or greater than the length of the heating chamber. The aerosol-generating article may comprise a substrate portion and a further mouthpiece portion. The mouthpiece portion may be located at a proximal end of the aerosol-generating article. The mouthpiece portion may comprise a filter.
[0062] As used herein, the terms "upstream" and "downstream" are used to describe the relative location of components or parts of components of an aerosol generating device with respect to the direction in which air flows through the aerosol generating device during use. An aerosol generating device according to the invention comprises a proximal end through which aerosol exits the device during use. The proximal end of an aerosol generating device may also be referred to as the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of an aerosol-generating article may also be referred to as the upstream end. Components or parts of components of an aerosol generating device may be described as being upstream or downstream of each other based on their relative location with respect to the airflow path of the aerosol generating device.
[0063] The proximal end of a heater assembly according to the invention is configured to be disposed within an aerosol generating device in a direction towards the mouth or downstream end of the device. The distal end of a heater assembly according to the invention is configured to be disposed within an aerosol generating device in a direction towards the distal or upstream end of the device. The longitudinal axis of the tubular heating chamber may extend between the proximal end of the heating chamber and the distal end of the heating chamber. The longitudinal axis of the tubular heating chamber may extend between the proximal end of the heater assembly and the distal end of the heater assembly.
[0064] In all aspects of the present disclosure, the heating element may include an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics.
[0065] As described, in any of the aspects of the present disclosure, the heating element may be part of the heating chamber of the heater assembly for the aerosol generating device. The heater assembly may comprise an internal heating element, or an external heating element, or both an internal heating element and an external heating element, where "internal" and "external" refer to the aerosol-forming substrate. The internal heating element may take any suitable form. For example, the internal heating element may take the form of a heating blade. Alternatively, the internal heater may take the form of a casing or substrate having different conductive portions or electrically resistive metal tubes. Alternatively, the internal heating element may be one or more heating needles or rods that pass through the center of the aerosol-forming substrate. Other alternatives include heating wires or filaments, such as Ni-Cr (nickel chromium), platinum, tungsten, or alloy wires or heating plates. Optionally, the internal heating element may be disposed in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal that has a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track on a suitable insulating material, such as a ceramic material, and then sandwiched in another insulating material, such as glass. The heater thus formed may be used to both heat the heating element and monitor its temperature during operation.
[0066] The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils on a dielectric substrate such as polyimide. The flexible heating foils may be shaped to fit the periphery of the substrate receiving cavity. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a molded integrated circuit device (MID), a ceramic heater, a flexible carbon fiber heater, or may be formed using a coating technique such as plasma deposition on a substrate of suitable shape. The external heating element may also be formed using a metal that has a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating material. An external heating element formed in this manner may be used both to heat the external heating element and to monitor the temperature of the external heating element during operation.
[0067] The heating element advantageously heats the aerosol-forming substrate by thermal conduction. The heating element may be in at least partial contact with the substrate or at least partial contact with the carrier on which the substrate is deposited. Alternatively, heat from either an internal or external heating element may be conducted to the substrate by a thermally conductive element.
[0068] In operation, the aerosol-forming substrate may be completely contained within the aerosol-generating device, in which case a user may puff on the mouthpiece of the aerosol-generating device. Alternatively, in operation, a smoking article containing the aerosol-forming substrate may be partially contained within the aerosol-generating device, in which case a user may puff on the smoking article directly.
[0069] The heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. Generally, the susceptor is a material capable of generating heat when penetrated by an alternating magnetic field. According to the present invention, the susceptor may be conductive, or magnetic, or both conductive and magnetic. The alternating magnetic field generated by one or several induction coils heats the susceptor, which then transfers heat to the aerosol-forming substrate, thereby forming the aerosol. The heat transfer may be primarily by thermal conduction. Such heat transfer is best when the susceptor is in intimate thermal contact with the aerosol-forming substrate. When an induction heating element is employed, it may be configured as an internal heating element as described herein, or as an external heater as described herein. When the induction heating element is configured as an internal heating element, the susceptor element is preferably configured as a pin or blade for penetrating the aerosol-generating article. When the induction heating element is configured as an external heating element, the susceptor element is preferably configured as a cylindrical susceptor that at least partially surrounds or forms a sidewall of the cavity.
[0070] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing a volatile compound capable of forming an aerosol. The volatile compound may be released by heating or burning the aerosol-forming substrate. As an alternative to heating or burning, in some cases the volatile compound may be released by a chemical reaction or by mechanical stimulation such as ultrasound. The aerosol-forming substrate may be solid or liquid, or may include both solid and liquid components. The aerosol-forming substrate may be part of an aerosol-generating article.
[0071] The aerosol-forming substrate may comprise nicotine. The nicotine-containing aerosol-forming substrate may be a nicotine salt matrix.
[0072] The aerosol-forming substrate may comprise a plant-derived material. The aerosol-forming substrate may comprise tobacco. The aerosol-forming substrate may comprise a tobacco-containing material comprising volatile tobacco flavour compounds which are released from the aerosol-forming substrate upon heating. Alternatively, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may comprise a homogenised plant-derived material. The aerosol-forming substrate may comprise a homogenised tobacco material. The homogenised tobacco material may be formed by agglomerating particulate tobacco.
[0073] The aerosol-forming substrate may include at least one aerosol former. The aerosol former is any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol during use and is substantially resistant to thermal decomposition at the operating temperature of the device. Suitable aerosol formers are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate, etc.), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.). A preferred aerosol former is a polyhydric alcohol or mixtures thereof (such as triethylene glycol, 1,3-butanediol, etc.). Preferably, the aerosol former is glycerin. When present, the homogenized tobacco material may have an aerosol former content of 5 weight percent or more on a dry weight basis, and preferably has an aerosol former content of 5 weight percent to 30 weight percent on a dry weight basis. The aerosol-forming substrate may contain other additives and ingredients, such as flavourants.
[0074] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate capable of emitting a volatile compound capable of forming an aerosol. The aerosol-generating article may be disposable.
[0075] The term "aerosol-generating device" as used herein refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-generating device may interact with one or both of an aerosol-generating article that includes an aerosol-forming substrate and a cartridge that includes an aerosol-forming substrate. In some examples, the aerosol-generating device may heat the aerosol-forming substrate to facilitate the release of volatile compounds from the substrate. An electrically operated aerosol-generating device may include an atomizer, such as an electric heater, for heating the aerosol-forming substrate to form an aerosol.
[0076] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device with an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol-generating system refers to the combination of an aerosol-generating device with an aerosol-generating article. In an aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device work together to generate an aerosol.
[0077] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of another example, embodiment, or aspect described herein.
[0078] Example 1. A heater assembly for an aerosol generating device, comprising: a tubular heating chamber for heating the aerosol-forming substrate, the tubular heating chamber having a proximal flared end; a heater casing disposed about the heating chamber, the heater casing having a proximal wall, the proximal wall having a circular groove extending proximally from an inner surface of the proximal wall, the circular groove having a chamfered inner wall, the chamfered inner wall and the proximal flared end of the tubular heating chamber having matching shapes, the proximal flared end of the tubular heating chamber being mounted in the circular groove of the proximal wall.
[0079] Example 2. The heater assembly of example 1, wherein the chamfered inner wall of the heater casing flares in the proximal direction.
[0080] Example 3. The heater assembly of any of Examples 1-2, wherein the tubular heating chamber comprises a distal flared end.
[0081] Example 4. The heater assembly of example 3, further comprising a heater mount, wherein the distal flared end of the tubular heating chamber is mounted within the heater mount.
[0082] Example 5. The heater assembly of Example 4, wherein the heater casing, the tubular heating chamber, and the heater mount define an airflow path through the heater assembly.
[0083] Example 6. A heater assembly as described in either Example 4 or Example 5, wherein the heater mount comprises an additional circular groove at a proximal end extending distally from an inner proximal surface of the heater mount, the circular groove comprising a chamfered inner wall, the chamfered inner wall flaring distally, the chamfered inner wall and the distal flared end of the tubular heating chamber having matching shapes, and the distal flared end of the tubular heating chamber is mounted within the circular groove of the heater mount.
[0084] Example 7. A heater assembly as described in any of Examples 1-6, wherein one or both of the chamfered inner wall of the proximal wall and the chamfered inner wall of the heater mount include at least one rib, preferably three ribs.
[0085] Example 8. The heater assembly of any of Examples 1-7, wherein the chamfered inner wall of the heater casing has the same chamfer angle as the proximal flared end of the tubular heating chamber.
[0086] Example 9. The heater assembly of Example 8, wherein the proximal flared end of the tubular heating chamber and the chamfered inner wall of the heater casing have a chamfer angle of 20° to 45°, preferably 25° to 40°, and more preferably about 30°.
[0087] Example 10. A heater assembly as described in any of Examples 1-9, wherein the length of the proximal flared end of the tubular heating chamber and the length of the chamfered inner wall of the heater casing are 0.5 to 5 millimeters, preferably 0.5 to 3 millimeters, more preferably 0.5 to 2 millimeters, and most preferably about 1 millimeter.
[0088] Example 11. The heater assembly of any of Examples 1-10, wherein the heater casing is a tubular heater casing, preferably the tubular heater casing is coaxially disposed around the tubular heating chamber.
[0089] Example 12. A heater assembly as described in any of Examples 1-11, wherein the heater casing comprises a proximal heater casing and a distal heater casing, the proximal heater casing comprising a proximal wall having a circular groove.
[0090] Example 13. The heater assembly of example 12, wherein the proximal heater casing comprises an air outlet and the distal heater casing comprises an air inlet.
[0091] Example 14. The heater assembly of either Example 12 or 13, further comprising a heater mount as described in Example 4, wherein the distal heater casing comprises the heater mount or the heater mount is mounted within the distal opening of the distal heater casing.
[0092] Example 15. The heater assembly of example 14, wherein the tubular heating chamber is sandwiched between or press-fitted into the proximal heater casing and the heater mount.
[0093] Example 16. A heater assembly as described in either Example 14 or Example 15, wherein a heater mount is mounted within a distal opening of the distal heater casing and a seal is disposed between the heater mount and an inner surface of the distal heater casing.
[0094] Example 17. A heater assembly as described in Example 16, wherein one or both of the chamfered inner wall of the proximal wall and the chamfered inner wall of the heater mount have at least one rib, preferably three ribs, and wherein the proximal heater casing, the distal heater casing, the tubular heating chamber, the heater mount, and the seal surround an air space, preferably the air space is an airtight space, more preferably the airtight space is hollow.
[0095] Example 18. The heater assembly of any of Examples 1-17, wherein the tubular heating chamber is made of metal, preferably stainless steel.
[0096] Example 19. The heater assembly of any of Examples 4-18, wherein one or more of the walls of the heater casing and the heater mount are made of a plastic material, preferably polyaryletherketone (PAEK), polyetheretherketone (PEEK), or polyphenylenesulfone (PPSU), more preferably polyphenylenesulfone (PPSU).
[0097] Example 20. The heater assembly of any of Examples 1-19, wherein the tubular heating chamber has an elongated shape, preferably the tubular heating chamber is an elongated hollow tube.
[0098] Example 21. The heater assembly of any of Examples 1-20, further comprising a heating element, preferably the heating element being disposed at least partially around the tubular heating chamber.
[0099] Example 22. The heater assembly of example 21, wherein the heating element comprises one or more conductive tracks on an electrically insulating substrate.
[0100] Example 23. The heater assembly of either Example 21 or Example 22, wherein the heating element is flexible and at least partially wrapped around the tubular heating chamber.
[0101] Example 24. An aerosol generating device comprising a heater assembly according to any one of Examples 1 to 23.
[0102] Example 25. An aerosol generating system comprising the aerosol generating device of Example 24 and an aerosol generating article having a base portion including an aerosol-forming substrate, the aerosol generating article being configured to be at least partially inserted into the tubular heating chamber.
[0103] Features described in relation to one embodiment may be equally applied to other embodiments of the invention.The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief description of the drawings]
[0104] [Figure 1] FIG. 1 illustrates one embodiment of a heater assembly for an aerosol generating device. [Diagram 2] 2A, 2B, 2C, and 2D each show a flared end of a tubular heating chamber having a chamfered inner wall. [Diagram 3] FIG. 3 illustrates one embodiment of an aerosol generating device that includes a heater assembly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0105] FIG. 1 shows a cross-section of a heater assembly 10. The heater assembly 10 comprises a tubular heating chamber 12 and a heater casing 14 disposed around the tubular heating chamber 12. The heater casing 14 comprises a proximal heater casing 16 and a distal heater casing 18. The proximal heater casing 16 comprises a proximal portion 20 and a distal portion 22. The proximal portion 20 has a smaller diameter than the distal portion 22. The proximal portion 20 and the distal portion 22 are both tubular. The proximal portion 20 defines a proximal airflow channel. The proximal portion further comprises an air outlet 24. The distal heater casing 18 comprises a proximal portion 26 and a distal portion 28. The proximal portion 26 has a larger diameter than the distal portion 28. The proximal portion 26 and the distal portion 28 are both tubular. The distal portion 28 defines a distal airflow channel. The distal portion 28 includes a distal air inlet 30 .
[0106] The heater assembly 10 further includes a heater mount 32. The heater mount 32 includes a proximal portion 34 and a distal portion 36. The proximal portion 34 has a larger diameter than the distal portion 36. Both the proximal portion 34 and the distal portion 36 are tubular.
[0107] The proximal and distal heater casings 16, 18 and heater mount 32 are made of a plastic material, preferably polyetheretherketone (PEEK) due to its advantageous mechanical and thermal insulating properties.
[0108] The proximal portion 20, the tubular heating chamber 12, the heater mount 32, and the distal portion 28 define an airflow channel that includes an airflow path 38. The proximal heater casing 16, the tubular heating chamber 12, the heater mount 32, and the distal heater casing 18 are coaxially disposed about a longitudinal axis 40 of the heater assembly 10. The proximal heater casing 16, the tubular heating chamber 12, the heater mount 32, and the distal heater casing 18 surround a hollow air space. The hollow air space provides insulation for the tubular heating chamber 12, thereby reducing heat loss from the tubular heating chamber 12 and heat transfer to the exterior of the heater assembly.
[0109] The wall of the tubular heating chamber 12 is a metal tube, which is preferably made of stainless steel. A flexible heating element 42 is wrapped around the outer surface of the metal tube to heat the tubular heating chamber 12, which in turn heats an aerosol-forming substrate (not shown) received within the interior space of the tubular heating chamber 12. The heating element 42 comprises a conductive heating track 44 on an electrically insulated flexible substrate 46. The electrically insulated flexible substrate 46 typically comprises a heat-resistant flexible polyimide film with the conductive heating track 44 forming a serpentine pattern on the film. The conductive heating track 44, which is connected to a power supply (not shown), generates heat when an electric current passes through the conductive track. In the embodiment shown, the proximal and distal edge portions of the flexible substrate 46 are not covered by the heating track 44. In other embodiments, different regions of the flexible substrate 46, or even the entire surface, may be covered by the heating track 44. Alternatively, the heating element 42 may be configured as an induction heating element including a susceptor and an induction coil (not shown).
[0110] The distal portion 22 of the proximal heater casing 16 includes a proximal wall 48. The proximal wall 48 includes a circular groove 50. The circular groove 50 includes a chamfered inner side wall 52, whereby the circular groove 50 has a right-angled trapezoidal cross section. Mounted within the circular groove 50 is a proximal flared end 54 of the tubular heating chamber 12. The chamfered inner side wall 52 and the proximal flared end 54 have the same chamfer.
[0111] The proximal portion 26 of the distal heater casing 18 includes a distal wall 56 with a distal opening 58. The distal portion 36 of the heat mount 32 is mounted within the distal opening 58. A seal 60 is disposed between the proximal portion 34 of the heater mount 32 and an inner surface of the proximal portion 26 of the distal heater casing 18, whereby the proximal portion 34 of the heater mount 32 is spaced from the inner wall of the distal heater casing 18. Additionally, the seal 60 is spaced from the tubular heating chamber 12. The seal 60 is an O-ring made from ethylene propylene diene monomer (EPDM) rubber. The seal 60 has a Shore hardness of 70A as determined by technical standard ISO 868 Type A. This hardness has been found to be soft enough for manufacturing tolerances, yet hard enough to apply force to the heater assembly 10 to provide a seal for the airflow path 38 and the integrity of the heater assembly 10. The seal 60 has an uncompressed thickness or diameter of 1 millimeter. This thickness has also been found to be adequate to accommodate manufacturing tolerances and to apply force to the heater assembly 10 to provide sealing of the airflow path 38 and integrity of the heater assembly 10.
[0112] The heater mount 32 includes a circular groove 62 with a chamfered inner wall 64 such that the circular groove 62 has a right-angled trapezoidal cross section. Within the circular groove 62 is mounted a distal flared end 66 of the tubular heating chamber 12.
[0113] Flared ends 54 and 66 of tubular heating chamber 12 are press-fit into circular grooves 50 and 62, respectively. Flared ends 54 and 66 are not surrounded by heating element 42.
[0114] 2A and 2B show a cross section of a chamfered sidewall 68 having a flared end 70. The chamfered sidewall 68 may be one or both of the chamfered inner sidewalls 52 and 64. The flared end 70 may be one or both of the flared ends 54 and 66. The chamfered sidewall 68 and the flared end 70 have a length 72 measured along the chamfer, a transverse length 74 measured in a direction perpendicular to the longitudinal axis 40, and an axial length 76 measured along the longitudinal axis 40. The axial length of the chamfered inner sidewalls 52 and 64 is between 0.8 millimeters and 4 millimeters, and the transverse length is between 0.5 millimeters and 2.5 millimeters. The axial length of the flared ends 54 and 66 is between 0.8 millimeters and 4 millimeters, and the transverse length is between 0.5 millimeters and 2.5 millimeters.
[0115] The chamfered sidewall 68 is chamfered at a chamfer angle 78. The flared end 70 is chamfered at a chamfer angle 80. The chamfer angles 78 and 80 are measured relative to the longitudinal axis 40 of the heater assembly 10. The chamfered sidewall 68 and the flared end 70 are parallel. Thereby, the chamfer angles 78 and 80 have the same absolute value. The chamfer angle 78 is between 20° and 45°, preferably between 25° and 40°, and more preferably about 30°. The chamfer angle 80 is between 20° and 45°, preferably between 25° and 40°, and more preferably about 30°. Both the chamfer angles 78 and 80 are between 20° and 45°, preferably between 25° and 40°, and more preferably about 30°. These chamfer angle ranges, particularly the 30° chamfer angle, provide improved impact resistance as the initial impact force traveling along the longitudinal axis of the heater assembly 10 is split into two smaller forces at a right angle.
[0116] FIG. 2C shows how the initial force running along the longitudinal axis F is divided into forces F1 (running along the chamfer) and F2 (running perpendicular to the chamfer). For example, at a chamfer angle of 30°, F1 is about 87% (cos 30°) of the initial force F. However, this force F1 is limited because the tubular heating chamber 12 cannot move along its flared end without expanding it. The second force F2 is about 50% (sin 30°) of the initial force F. F2 pushes the chamfered inner walls 52 and 64 towards the tubular hollow core. However, the conical structure already reduces F2 to a sustainable force that the elastic properties of the plastic part can maintain when the magnitude of F is within the range of the drop test forces.
[0117] 2D shows a cross section of a chamfered sidewall 82. The chamfered sidewall 82 may be one or both of the chamfered inner walls 52 and 64. The chamfered sidewall 82 includes three ribs 84. The ribs 84 press against the surface of the flared end.
[0118] Figure 3 shows a cross-section of an aerosol generating device 86. The aerosol generating device 86 comprises the heater assembly 10 of Figure 1. The aerosol generating device 86 further comprises a power source 88 and control electronics 90. The power source 88 may be a rechargeable battery. At the opening 92, an aerosol-forming substrate (not shown) may be at least partially inserted into the tubular heating chamber 12 of the heater assembly 10.
Claims
1. A heater assembly for an aerosol generator, A tubular heating chamber for heating an aerosol-forming substrate, wherein the tubular heating chamber has a proximal flared end, A heater assembly comprising: a heater casing disposed around the heating chamber, wherein the heater casing has a proximal wall, the proximal wall has a circular groove extending proximal from the inner surface of the proximal wall, the circular groove has a chamfered inner wall, the chamfered inner wall and the proximal flared end of the tubular heating chamber have a matching shape, and the proximal flared end of the tubular heating chamber is mounted in the circular groove of the proximal wall.
2. The heater assembly according to claim 1, wherein the chamfered inner wall of the heater casing is flared in the proximal direction.
3. The heater assembly according to claim 1, wherein the tubular heating chamber has a distal flared end, preferably the heater assembly further comprises a heater mount, and the distal flared end of the tubular heating chamber is mounted inside the heater mount.
4. The heater assembly according to claim 3, further comprising the heater mount, wherein the distal flared end of the tubular heating chamber is mounted within the heater mount, the heater mount having an additional circular groove at its proximal end extending distally from the inner proximal surface of the heater mount, the circular groove having a chamfered inner wall, the chamfered inner wall being flared distally, the chamfered inner wall and the distal flared end of the tubular heating chamber having a coincident shape, and the distal flared end of the tubular heating chamber is mounted within the circular groove of the heater mount.
5. The heater assembly according to claim 1, wherein one or both of the chamfered inner wall of the proximal wall and the chamfered inner wall of the heater mount are provided with at least one rib, preferably three ribs.
6. The heater assembly according to claim 1, wherein the chamfered inner wall of the heater casing has the same chamfer angle as the proximal flared end of the tubular heating chamber.
7. The heater assembly according to claim 6, wherein the proximal flared end of the tubular heating chamber and the chamfered inner wall of the heater casing have a chamfer angle of 20° to 45°, preferably 25° to 40°, and more preferably about 30°.
8. The heater assembly according to claim 1, wherein the length of the proximal flared end of the tubular heating chamber and the chamfered inner wall of the heater casing is 0.5 to 5 millimeters, preferably 0.5 to 3 millimeters, more preferably 0.5 to 2 millimeters, and most preferably about 1 millimeter.
9. The heater assembly according to claim 1, wherein the heater casing comprises a proximal heater casing and a distal heater casing, and the proximal heater casing comprises the proximal wall having the circular groove.
10. The heater assembly according to claim 9, wherein the tubular heating chamber has a distal flared end, the heater assembly further comprises a heater mount, the distal flared end of the tubular heating chamber is mounted inside the heater mount, the distal heater casing comprises the heater mount, or the heater mount is mounted inside the distal opening of the distal heater casing.
11. The heater assembly according to claim 10, wherein the tubular heating chamber is sandwiched between the proximal heater casing and the heater mount, or press-fitted into them.
12. The heater assembly according to claim 10, wherein the heater mount is installed inside the distal opening of the distal heater casing, and a seal is disposed between the heater mount and the inner surface of the distal heater casing.
13. The heater assembly according to claim 12, wherein one or both of the chamfered inner wall of the proximal wall and the chamfered inner wall of the heater mount have at least one rib according to claim 5, preferably three ribs, and the proximal heater casing, the distal heater casing, the tubular heating chamber, the heater mount, and the seal surround an air space, preferably the air space is airtight, more preferably the airtight space is hollow.
14. An aerosol generator comprising the heater assembly described in claim 1.
15. An aerosol generating system comprising an aerosol generating device according to claim 14 and an aerosol generating article having a base portion including an aerosol forming substrate, wherein the aerosol generating article is configured to be at least partially inserted into the tubular heating chamber.