Heater assembly with serpentine conductive track

Abstract

The invention relates to a heater assembly for an aerosol-generating device. The heater assembly comprises a cavity extending along a longitudinal axis between a first end and a second end, the first end being arranged for insertion of an aerosol-forming substrate into the cavity and a heating element at least partially circumscribing the cavity. The heating element comprises a single electrically conductive track comprising a plurality of parallelly extending elongate portions. Each elongate portion extends along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity. The single electrically conductive track further comprises a plurality of turns arranged to alternately interconnect neighboring ends of adjacent elongate portions.

Description

[0001] HEATER ASSEMBLY WITH SERPENTINE CONDUCTIVE TRACK

[0002] The present disclosure relates to a heater assembly for an aerosol-generating device. The present disclosure further relates to an aerosol-generating device. The present disclosure further relates to an aerosol-generating system comprising an aerosol-generating device and an aerosol-forming substrate.

[0003] It is known to provide an aerosol-generating device for generating an inhalable vapor. Such devices may heat aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate are volatilized without burning the aerosolforming substrate. The aerosol-forming substrate may be provided as part of a substrate plug. The substrate plug may have a rod shape for insertion of the substrate plug 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 for heating the aerosol-forming substrate once the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device.

[0004] It would be desirable to provide an aerosol-generating device that is adaptable to different types of aerosol-forming substrates. It would be desirable to provide an aerosolgenerating device that is adaptable to different user preferences. It would be desirable to provide an aerosol-generating device that allows to tune cooling of an airflow to a desired temperature before being inhaled by a user. It would be desirable to provide an aerosolgenerating device that allows to tune condensation after evaporation of an aerosol-forming substrate. It would be desirable to provide an aerosol-generating device which allows to improve heating efficiency. It would be desirable to provide an aerosol-generating device that allows to improve the user experience.

[0005] According to an embodiment of the invention there is provided a heater assembly for an aerosol-generating device. The heater assembly may comprise a cavity. The cavity may extend along a longitudinal axis between a first end and a second end. The first end may be arranged for insertion of an aerosol-forming substrate into the cavity. The heater assembly may comprise a heating element at least partially circumscribing the cavity. The heating element may comprise a single electrically conductive track comprising a plurality of parallelly extending elongate portions. Each elongate portion may extend along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity. The single electrically conductive track further may comprise a plurality of turns arranged to alternately interconnect neighboring ends of adjacent elongate portions.

[0006] According to an embodiment of the invention there is provided a heater assembly for an aerosol-generating device. The heater assembly comprises a cavity extending along a longitudinal axis between a first end and a second end. The first end is arranged for insertion of an aerosol-forming substrate into the cavity. The heater assembly comprises a heating element at least partially circumscribing the cavity. The heating element comprises a single electrically conductive track. The track comprises a plurality of parallelly extending elongate portions. Each elongate portion extends along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity. The single electrically conductive track further comprises a plurality of turns arranged to alternately interconnect neighboring ends of adjacent elongate portions.

[0007] The heater assembly may be adaptable to different types of aerosol-forming substrates. The heater assembly may be adaptable to different user preferences. The aerosol-generating device may allow to tune cooling of an airflow to a desired temperature before being inhaled by a user. The aerosol-generating device may allow to tune condensation after evaporation of an aerosol-forming substrate. The heater assembly may allow to improve heating efficiency. The heater assembly may allow to improve the user experience.

[0008] The heater assembly may allow usage of more compact aerosol-generating articles and aerosol-forming substrates. The heater assembly may allow usage of more compact aerosol-generating articles having no filter element. The heater assembly may improve sustainability of the aerosol-generating system. The heater assembly may allow usage of aerosol-generating articles and aerosol-forming substrates of lower production cost. The aerosol-generating system may provide reduced leakage of liquid aerosol-forming substrate. By providing the heater assembly of the invention, temperature gradients within the aerosolforming substrate may be reduced. The heater assembly of the invention may provide continuous heating to an inserted aerosol-forming substrate. The heater assembly of the invention may improve aerosol delivery from a filter-free aerosol-forming substrate and aerosol-generating article.

[0009] Each elongate portion may extend along at least 50 percent of a circumference of the cavity within a plane perpendicular to the longitudinal axis of the cavity.

[0010] The cavity may have a circular cross-section. The cavity may have a rectangular cross-section. The cavity may have an oval cross-section. The cavity may have an elliptical cross-section. The cavity may be cylindrical. The cavity may be cuboid-shaped. The cavity may be flat. The cavity may be configured to receive an aerosol-generating article. The aerosol-generating article may comprise the aerosol-forming substrate. The cavity may be configured to conform to the shape of one or both of the aerosol-generating article and the aerosol-forming substrate. The shape of the heating element may be configured to conform to the shape of the cavity. The cavity may comprise a sidewall. The sidewall of the cavity may be tubular-shaped. The sidewall of the cavity may be arranged at a periphery of the cavity. The sidewall may at least partially circumscribe the cavity.

[0011] The first end of the cavity may be a proximal end of the cavity. The first end of the cavity may be a downstream end of the cavity. The second end of the cavity may be a distal end of the cavity. The second end of the cavity may be an upstream end of the cavity. The first end of the cavity may comprise an opening. The opening of the first end of the cavity may be configured for receiving the aerosol-forming substrate. The aerosol-forming substrate may be inserted into the cavity through the opening of the first end of the cavity. The second end of the cavity may comprise a base. The base may be configured to be integral with the sidewall of the cavity. The second end of the cavity may be a closed end.

[0012] The opening of the first end of the cavity may be arranged substantially perpendicular to the longitudinal axis of the cavity. The opening of the first end of the cavity may be arranged parallel to the elongate portions.

[0013] The heating element may at least partially surround the cavity. The heating element may fully circumscribe the cavity. The heating element may fully surround the cavity. The sidewall of the cavity may comprise the heating element.

[0014] The heating element may have a circular cross-section. The heating element may have a rectangular cross-section. The heating element may have an oval cross-section. The heating element may have an elliptical cross-section. The heating element may be cylindrical. The heating element may be tubular-shaped. The heating element may be a hollow cylinder. The heating element may be cuboid-shaped.

[0015] The heating element may have a first end. The first end of the heating element may be configured for insertion of the aerosol-forming substrate. The first end of the heating element may be configured for insertion of the aerosol-generating article. The first end of the heating element may have an opening. The opening of the first end of the heating element may be configured for receiving the aerosol-forming substrate. The aerosol-forming substrate may be inserted into the cavity via the opening of the first end of the heating element. The heating element may have a second end. The second end of the heating element may be arranged on an opposite side to the first end. The first end of the heating element may be arranged at the first end of the cavity. The second end of the heating element may be arranged at the second end of the cavity.

[0016] The first end of the heating element may be a proximal end of the heating element. The first end of the heating element may be a downstream end of the heating element. The second end of the heating element may be a distal end of the heating element. The second end of the heating element may be an upstream end of the heating element.

[0017] The track may be a printed track. The track may be formed from a wire. The track may be formed from a metal wire. One or more of the elongate portions may be configured to be substantially circular. One or more of the elongate portions may be configured to be circular. One or more of the elongate portions may be configured to be rectangular. One or more of the elongate portions may be configured to be oval. One or more of the elongate portions may be configured to be elliptical. One or more of the elongate portions may be linear. One or more of the elongate portions may be made from an electrically conductive material. One or more of the elongate portions may be made from an electrically resistive material.

[0018] Each elongate portion may consist of electrically resistive material. Each elongate portion may be made from electrically resistive material.

[0019] Each elongate portion may be C-shaped. Each elongate portion may be configured as a single arc. Each elongate portion may linearly extend along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity.

[0020] Each elongate portion may consist of a C-shaped line of electrically resistive material. Each elongate portion may consist of electrically resistive material being configured as a single arc. Each elongate portion may consist of electrically resistive material being linearly arranged along at least 50 percent of a circumference of the cavity. Each elongate portion may consist of electrically resistive material linearly extending along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity.

[0021] Each elongate portion may be configured as a geodesic. Each elongate portion may be configured as a geodesic extending between the ends of the elongate portion. Each elongate portion may be configured as a geodesic extending within a plane substantially perpendicular to the longitudinal axis of the cavity. Each elongate portion may be configured as a geodesic extending along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity.

[0022] Each elongate portion may consist of electrically resistive material being configured as a geodesic. Each elongate portion may consist of electrically resistive material being configured as a geodesic extending between the ends of the elongate portion. Each elongate portion may consist of electrically resistive material being configured as a geodesic extending within a plane substantially perpendicular to the longitudinal axis of the cavity. Each elongate portion may consist of electrically resistive material being configured as a geodesic extending along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity. Each elongate portion may consist of electrically conductive material being configured as a geodesic extending along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity. When the heating element is unfolded into a plane, each elongate portion may be configured as a straight line. When the heating element is unfolded into a plane, each elongate portion may consist of a straight line of electrically resistive material. When the heating element is unfolded into a plane, each elongate portion may consist of a straight line of electrically conductive material. When the heating element is unrolled into a plane, each elongate portion may be configured as a straight line. When the heating element is unrolled into a plane, each elongate portion may consist of a straight line of electrically resistive material. When the heating element is unrolled into a plane, each elongate portion may consist of a straight line of electrically conductive material.

[0023] A width of each elongate portion may be constant along the extent of the elongate portion. The width of the elongate portion may be the spatial extent of the elongate portion in the direction of the longitudinal axis of the cavity. The width of the elongate portion may be the spatial extent of the electrically resistive material in the direction of the longitudinal axis of the cavity. The width of the elongate portion may be the spatial extent of the electrically conductive material in the direction of the longitudinal axis of the cavity. The width of the elongate portion may be the spatial extent of the elongate portion parallel to the longitudinal axis of the cavity. The width of the elongate portion may be the spatial extent of the electrically resistive material parallel to the longitudinal axis of the cavity.

[0024] Adjacent elongate portions may be arranged next to each other. A first elongate portion being arranged adjacent to a second elongate portion may be the elongate portion that is arranged closest to the second portion along the direction of the longitudinal axis of the cavity.

[0025] Neighboring ends of a first elongate portion and a second elongate portion which are arranged adjacent to each other may be the ends of the first elongate portion and the second elongate portion which are arranged closest to each other in the direction of the longitudinal axis of the cavity.

[0026] Elongate portions may be distributed between the first end of the heating element and the second end of the heating element. Turns may be distributed between the first end of the heating element and the second end of the heating element.

[0027] The circumference of the cavity may be a closed loop around of the cavity within a plane perpendicular to the longitudinal axis of the cavity.

[0028] The longitudinal axis of the cavity may extend between a distal end of the cavity and a proximal end of the cavity. The longitudinal axis of the cavity may extend between an upstream end of the cavity and a downstream end of the cavity. The longitudinal axis of the cavity may extend from the first end of the cavity to the second end of the cavity. The longitudinal axis of the cavity may extend from the second end of the cavity to the first end of the cavity. The longitudinal axis of the cylindrical cavity with a circular cross-section may be the axis through the centre of each circular cross-section of the cylinder.

[0029] One or more of the turns may be substantially linear. One or more of the turns may extend substantially parallel to the longitudinal axis of the cavity. One or more of the turns may be arranged substantially perpendicular to the elongate portions. One or more of the turns may be arc -shaped. One or more of the turns may be curved. One or more of the turns may be arranged substantially parallel to each other. One or more of the turns may be semicircular.

[0030] One or more of the turns may be made from the same material as the elongate portions. One or more of the turns may be configured to be continuous with the elongated portions interconnected by the turn. One or more of the turns may be made from an electrically conductive material. One or more of the turns may be made from an electrically resistive material.

[0031] The track may comprise n first portions, wherein n is an integral number equal or greater than 2, preferably equal or greater than 3, more preferably equal or greater than 5, more preferably equal or greater than 9. n may an odd integral number equal or greater than 3. The track may comprise n-1 turns. Each turn may interconnect two adjacent elongate portions. The length of the turn may substantially correspond to the distance along the direction of the longitudinal axis of the cavity between the adjacent first portions interconnected by the turn.

[0032] The heating element may comprise two electrical contacts arranged at an end of the heating element adjacent the second end of the cavity. The electrical contacts may be provided at opposing ends of the track.

[0033] The track may comprise one or more connecting portions. The connecting portion may be arranged between an end of one of the elongate portions which is not in contact with one of the turns and one of the electrical contacts. The connecting portion may be configured to connect a free end of one of the elongate portions and one of the electrical contacts. The connecting portion may be arranged substantially parallel to the longitudinal axis of the cavity. The connecting portion may extend across substantially the entire heating element in the direction of longitudinal axis of the cavity. The connecting portion may be linear. The connecting portion may be made from the same material as one or both of the elongate portions and the turns. The connecting portion may be made from an electrically conductive material. The connecting portion may be made from an electrically resistive material. The connecting portion may be arranged to be in contact with one of the electrical contacts. The connecting portion may be continuous with the elongate portion to which it is connected. The connecting portion may be configured to connect an end of a portion of the track comprising the elongate portions and the turns with one of the electrical contacts. The connecting portion may bridge gaps between a portion of the track comprising the elongate portions and the turns and the electrical contacts to provide a continuous track which may be supplied with power from a power supply connected to the electrical contacts.

[0034] The electrical contacts may be configured to be connected to a power source. The power source may be part of an aerosol-generating device. The electrical contacts may be configured such that power may be supplied to the track of the heating element via the electrical contacts.

[0035] The electrical contacts may be arranged at the second end of the heating element. The electrical contacts may be arranged a distal end of the heating element. The electrical contacts may be arranged at an upstream end of the heating element. The electrical contacts may be arranged at a circumference of the second end of the heating element. The electrical contacts may be arranged abutting each other. The electrical contacts may be arranged next to each other. The electrical contacts may be configured to abut to the second end of the heating element. The electrical contacts may be attached to the second end of the heating element.

[0036] The track may comprise a first end and a second end. The first end of the track may be in contact with one electrical contact. The second end of the track may be in contact with the other electrical contact.

[0037] In use, the electrically conductive track may be supplied with power from an electrical power supply. The power supply may heat the electrically conductive track. The electrically conductive track may heat at least a portion of an aerosol-forming substrate adjacent to the heating element to volatize at least a portion of the aerosol-forming substrate.

[0038] The arrangement and configuration of the elongate portions and turns may be varied to improve the user experience. The arrangement and configuration of the elongate portions and turns may be varied to tune the user experience. By varying one or more the spacing between the elongate portions and the spatial configuration of the elongate portions, the heating profile delivered by the heating element may be adjusted in dependence of the characteristics of the aerosol-forming substrate. To provide a more intense heating profile, the spacing between one or more pairs of adjacent elongate portions may be decreased and, additionally or alternatively, the spatial dimensions of the elongate portions may be varied. To provide a less intense heating profile, the spacing between one or more pairs of elongate portions may be increased and, additionally or alternatively, the spatial dimensions of the elongate portions may be varied. The local heating profile delivered by the heating element to a portion of the aerosol-forming substrate may be tuned by varying the spacing between elongate portions and the spatial configuration of the elongate portions in regions of the heating element arranged adjacent to the specific portion of the aerosol-forming substrate. By providing the heater assembly of the present invention, different heating profiles may be delivered to different portions of the aerosol-forming substrate. By adjusting one or more of the spacing between elongate portions and the spatial configuration of the elongate portions, the electrical resistance of the track may be adjusted. The heater assembly may deliver a uniform heat flux or a non-uniform heat flux.

[0039] The heating element may comprise at least 5 elongate portions, preferably at least 6 elongate portions, more preferably at least 7 elongate portions, more preferably at least 8 elongate portions, and more preferably at least 9 elongate portions.

[0040] By providing a plurality of elongate portions, the heating profile delivered by the heating may be tuned.

[0041] Each elongate portion may extend along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

[0042] Each elongate portion may linearly extend along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

[0043] Each elongate portion may consist of electrically resistive material linearly extending along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

[0044] Each elongate portion may be configured as a geodesic extending along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

[0045] Each elongate portion may consist of electrically resistive material being configured as a geodesic extending along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

[0046] Each elongate portion may consist of electrically conductive material being configured as a geodesic extending along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity. Each elongate portion may partially circumscribe the cavity. Each elongate portion may partially surround the cavity. Each elongate portion may substantially fully circumscribe the cavity. Each elongate portion may substantially fully surround the cavity.

[0047] The elongate portions may be unevenly spaced.

[0048] The distance between adjacent elongate portions may be varied. Each distance between adjacent elongate portions may be varied.

[0049] A distance between adjacent elongate portions may change along a direction of the longitudinal axis of the cavity.

[0050] The distance between adjacent elongate portions may be the distance between such adjacent portions in the direction of the longitudinal axis of the cavity. The distance between adjacent elongate portions may the average distance between such adjacent elongate portions in the direction of the longitudinal axis of the cavity.

[0051] The distance between adjacent elongate portions may successively increase along the direction of the longitudinal axis of the cavity.

[0052] The distance between the adjacent portions may successively decrease along the direction of the longitudinal axis. The distance between the adjacent portions may successively increase from the first end of the cavity to the second end of the cavity. The distance between the adjacent portions may successively decrease from the first end of the cavity to the second end of the cavity.

[0053] The distance between adjacent elongate portions may successively increase by 2.5 percent, preferably 5 percent, more preferably 7.5 percent, and more preferably 10 percent along the direction of the longitudinal axis of the cavity.

[0054] The distance between adjacent elongate portions may successively decrease by 2.5 percent, preferably 5 percent, more preferably 7.5 percent, and more preferably 10 percent along the direction of the longitudinal axis of the cavity.

[0055] At least some of the elongate portions may be evenly spaced. All of the elongate portions may be evenly spaced.

[0056] The distance between adjacent portions may be the same.

[0057] The distance between adjacent elongate portions may be between 0.6 millimeter and 2.7 millimeters.

[0058] Each elongate portion may have a width extending in the direction of the longitudinal axis of the cavity. Two or more, preferably all elongate portions may have different widths. Two or more, preferably all elongate portions may have different widths differing by at least 5 percent, preferably at least 7.5 percent, more preferably at least 10 percent.

[0059] The width of the elongate portion may be the spatial extent of the elongate portion in the direction of the longitudinal axis of the cavity. The width of a linear elongate portion may be a line width. The width of the elongate portion may be constant along the extent of the elongate portion. The width of the elongate portion may vary along the extent of the elongate portion.

[0060] The width of adjacent elongate portions may successively increase along the direction of the longitudinal axis of the cavity.

[0061] The width of adjacent elongate portions may successively decrease along the direction of the longitudinal axis of the cavity. The width of adjacent elongate portions may successively increase from the first end of the cavity to the second end of the cavity. The width of adjacent elongate portions may successively decrease from the first end of the cavity to the second end of the cavity.

[0062] The width of adjacent elongate portions may successively increase by one of between 1 percent and 10 percent, between 2.5 percent and 7.5 percent, and between 4 percent and 6 percent along the direction of the longitudinal axis of the cavity.

[0063] The width of adjacent elongate portions may successively decrease by one of between 1 percent and 10 percent, between 2.5 percent and 7.5 percent, and between 4 percent and 6 percent along the direction of the longitudinal axis of the cavity.

[0064] Each elongate portion may have a width extending in the direction of the longitudinal axis of the cavity. The width of each elongate portion may be the same.

[0065] Each of the elongate portions may have a thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity. Two or more, preferably all elongate portions may have different thicknesses. Two or more, preferably all elongate portions may have different thicknesses differing by at least 5 percent, preferably at least 7.5 percent, more preferably at least 10 percent.

[0066] The thickness of adjacent elongate portions may successively increase along the direction of the longitudinal axis of the cavity.

[0067] The thickness of adjacent elongate portions may successively decrease along the direction of the longitudinal axis of the cavity. The thickness of adjacent elongate portions may successively increase from the first end of the cavity to the second end of the cavity. The thickness of adjacent elongate portions may successively decrease from the first end of the cavity to the second end of the cavity.

[0068] The thickness of adjacent elongate portions may successively increase by one of between 1 percent and 10 percent, between 2.5 percent and 7.5 percent, and between 4 percent and 6 percent along the direction of the longitudinal axis of the cavity.

[0069] The thickness of adjacent elongate portions may successively decrease by one of between 1 percent and 10 percent, between 2.5 percent and 7.5 percent, and between 4 percent and 6 percent along the direction of the longitudinal axis of the cavity. The thickness of the elongate portion may be constant along the extent of the elongate portion. The thickness of the elongate portion may vary along the extent of the elongate portion.

[0070] Each of the elongate portions may have a thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity. The thickness of each elongate portion may be the same.

[0071] The thickness of each elongate portion may be constant.

[0072] The cross-sectional area of the track may be varied. The cross-sectional area of one or more of the elongate portions may be varied. The electric resistance of the track may be varied. The electric resistance of one or more the elongate portions may be varied. The electric resistance of the track may be varied by varying the cross-sectional area of the track. The electric resistance of the one or more elongate portions may be varied by varying the cross-sectional area of the one or more elongate portions. The cross-sectional area of the track may be varied by varying one or both of the width of the track and the thickness of the track. The cross-sectional area of the one or more elongate portions may be varied by varying one or both of the width of the track and the thickness of the one or more elongate portions.

[0073] The heating element may comprise a first region and a second region. Adjacent elongate portions in the first region may be spaced apart by a first distance. Adjacent elongate portions in the second region may be spaced apart by a second distance.

[0074] The first region of the heating element may be configured to abut a first region of the cavity. The second region of the heating element may be configured to abut a second region of the cavity. The first region of the heating element may be configured to abut a first region of one or both of the aerosol-generating article and aerosol-forming substrate inserted into the cavity. The second region of the heating element may be configured to abut a second region of one or both of the aerosol-generating article and aerosol-forming substrate inserted into the cavity. The first region of the heating element may be configured to heat the first region of one or both of the aerosol-generating article and aerosol-forming substrate. The second region of the heating element may be configured to heat the second region of one or both of the aerosol-generating article and aerosol-forming substrate. The heating profile delivered by the first region of the heating element may be different to the heating profile delivered by the second region of the heating element. By providing the first and second regions of the heating element, the heating profile delivered by the heating element may be varied along the aerosol-forming substrate. By providing the first and second regions of the heating element, the user experience may be improved. By providing the first and second region of the heating element, the user experience may be tuned.

[0075] The first distance may be the same as the second distance. The first distance may be different from the second distance.

[0076] The elongate portions of the first region may have a first width extending in the direction of the longitudinal axis of the cavity. The elongate portions of the second region may have a second width extending in the direction of the longitudinal axis of the cavity.

[0077] The first width may be the same as the second width.

[0078] The first width may be different from the second width.

[0079] The elongate portions of the first region may have a first thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity. The elongate portions of the second region may have a second thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity.

[0080] The first thickness may be the same as the second thickness.

[0081] The first thickness may be different from the second thickness.

[0082] The first region and the second region may be spaced apart by a third distance. The third distance may be different to one or both of the first distance and the second distance. The third distance may be at least twice the first distance. The third distance may be at least twice the second distance. The third distance may be at least four times the first distance. The third distance may be at least four times the second distance.

[0083] The third distance may be larger than one or both of the first distance and the second distance. The first region and the second region may be interconnected by one turn.

[0084] The ratio between the third distance and the first distance may be of between 1.5 and 8. The ratio between the third distance and the second distance may be of between 1.5 and 8. The ratio between the third distance and the first distance may be of between 3 and 7. The ratio between the third distance and the second distance may be of between 3 and 7.

[0085] The first region and the second region may be arranged at opposite ends of the heating element. The first region may be arranged at the first end of the heating element. The second region may be arranged at the second end of the heating element.

[0086] The heating element may comprise three or more regions of elongate portions. Adjacent elongate portions in each region may be spaced by a region-specific distance. The region-specific distances may vary from region to region. The region-specific distances may be the same for all regions. The regions of elongate portions may be separated by regions void of elongate portions. Two neighboring regions of elongate portions may be interconnected by one turn. The distance between the regions may vary. The distance between the regions may be the same.

[0087] Elongate portions of each region may have a region-specific width extending in the direction of the longitudinal axis of the cavity. The width may vary from region to region. The width may be the same for each region. Elongate portions of each region may have a regionspecific thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity. The thickness may vary from region to region. The thickness may be the same for each region.

[0088] The heating element may comprise a first base layer. The track may be arranged on the first base layer. The first base layer may have an inner surface. The inner surface may be arranged facing towards the cavity. The first base layer may have an outer surface. The outer surface may be arranged facing away from the cavity. The track may be arranged on the outer surface of the first base layer. The track may be arranged on the inner surface of the first base layer.

[0089] The first base layer may be flexible. The first base layer may be made from an insulating material. The track maybe printed onto the first base layer. The first base layer may be a dielectric material. The first base layer may be made from a polymeric material, such as polyimide.

[0090] The first base layer may have a circular cross-section. The first base layer may have a rectangular cross-section. The first base layer may have an oval cross-section. The first base layer may have an elliptical cross-section. The first base layer may be cylindrical. The first base layer may be tubular-shaped. The first base layer may be a hollow cylinder. The first base layer may be cuboid-shaped.

[0091] The heating element may comprise a second base layer. The track may be configured to abut the first base layer and the second base layer. The track may be arranged between the first base layer and the second base layer.

[0092] The second base layer may be flexible. The second base layer may be made from an insulating material. The second base layer may be a dielectric material. The second base layer may be made from a polymeric material, such as polyimide.

[0093] The second base layer may have a circular cross-section. The second base layer may have a rectangular cross-section. The second base layer may have an oval crosssection. The second base layer may have an elliptical cross-section. The second base layer may be cylindrical. The second base layer may be tubular-shaped. The second base layer may be a hollow cylinder. The second base layer may be cuboid-shaped.

[0094] By providing one or both of a first and second base layer, the risk of damaging the conductive track may be reduced.

[0095] The track may be a serpentine track. The track may follow a back and forth pattern. The track may be configured as a continuous track.

[0096] The heating element may be configured to be cylindrical. The heating element may be configured to be tubular.

[0097] The heater assembly may comprise a sleeve. The sleeve may be configured to at least partially circumscribe the cavity. The sleeve may be configured to be tubular. The sleeve may have a circular cross-section. The sleeve may have a rectangular cross-section. The sleeve may have an oval cross-section. The sleeve may have an elliptical cross-section. The sleeve may be cylindrical. The sleeve may be cuboid-shaped. The sleeve may be flat. The sleeve may be configured to receive an aerosol-generating article. The sleeve may be configured as a metal tube.

[0098] The sleeve may be configured to at least partially surround the cavity. The sleeve may be configured to fully circumscribe the cavity. The sleeve may be configured to fully surround the cavity.

[0099] The sleeve may comprise a first end. The first end of the sleeve may be a proximal end of the sleeve. The first end of the sleeve may be downstream end of the sleeve. The first end of the sleeve may be arranged at the first end of the cavity. The first end of the sleeve may be arranged at the first end of the heating element. The first end of the sleeve may comprise an opening. The opening of the first end of the sleeve may be configured for insertion of the aerosol-forming substrate. The opening of the first end of the sleeve may be configured for insertion of the aerosol-generating article.

[0100] The sleeve may comprise a second end. The second end of the sleeve may be a distal end of the sleeve. The second end of the sleeve may be an upstream end of the sleeve. The second end of the sleeve may be arranged at the second end of the cavity. The second end of the sleeve may be arranged at the second end of the heating element. The second end of the sleeve may comprise a base. The second end of the sleeve may be a closed end.

[0101] The heating element may be attached to the sleeve. The heating element may be attached to an outer wall of the sleeve. The first base layer may be configured to be in contact with the sleeve.

[0102] The heating element may be configured to at least partially circumscribe the sleeve.

[0103] The heating element may be configured to at least partially surround the sleeve. The heating element may be configured to fully surround the sleeve. The heating element may be configured to fully circumscribe the sleeve. The sleeve may be the sidewall of the cavity. The heating element may be configured to heat the sleeve. The sleeve may be configured to heat one or both of the aerosol-forming substrate and aerosol-generating article inserted into the sleeve. The heating element may be configured to be in contact with the sleeve.

[0104] The sleeve may be made from a thermally conductive material.

[0105] The sleeve may be made from one of stainless steel and aluminium. The sleeve may be made from a metallic material.

[0106] A sidewall of the sleeve may have a thickness of between 25 micrometers and 600 micrometers, preferably of between 50 micrometers and 400 micrometers, and more preferably of between 80 micrometers and 300 micrometers. The cavity may have a diameter of between 2 millimeters and 12 millimeters, preferably of between 4 millimeters and 10 millimeters, and more preferably of between 5 millimeters and 8 millimeters.

[0107] The heater assembly may comprise two or more heating elements as described herein.

[0108] A first heating element as described herein may be arranged proximal to a second heating element as described herein. The first heating element may at least partially circumscribe a first region of the cavity. The second heating element may at least partially circumscribe a second region of the cavity. The first heating element may be configured to heat a first region of one or both of the aerosol-forming substrate and aerosol-generating article. The first heating element may be configured to deliver a first heating profile to the first region of one or both the aerosol-forming substrate and the aerosol-generating article. The second heating element may be configured to deliver a second heating profile to the second region of one or both of the aerosol-forming substrate and the aerosol-generating article. The first heating profile may be different to the second heating profile. By providing two or more heating elements as described herein, the user experience may be tailored to the individual needs of the user. By providing two or more heating elements as described herein, the user experience may be improved.

[0109] The heating element may be configured as an electrically resistive heating element. The track may be configured to be a resistively heated track. Electrical power may be supplied to the resistively heated track. An electrical current may flow through the track. The resistively heated track may be heated by the supply of electrical power.

[0110] The heating element may be configured as an induction heating element. The track may be configured to be a susceptor track. The heater assembly may comprise an inductor configured to heat the induction heating element. The inductor may be configured for heating the susceptor track. The inductor may generate an alternating magnetic field. The inductor may at least partially circumscribe the induction heating element. The inductor may at least partially circumscribe the susceptor track.

[0111] The heater assembly may comprise an additional heating element. The additional heating element may comprise a susceptor element.

[0112] The susceptor element may comprise a heating blade. The susceptor element may comprise a heating needle. The susceptor element may comprise a heating rod. The susceptor element may be configured to penetrate the aerosol-forming substrate when the substrate is inserted into the cavity. The second end of the cavity may be configured for insertion of the susceptor element. The second end of the heating element may be configured for insertion of the susceptor element. The susceptor element may be arranged at least partially within the cavity of the heater assembly. The susceptor element may be arranged at least partially within the heating element of the heater assembly.

[0113] The susceptor element may at least partially circumscribe the cavity of the heater assembly.

[0114] The heater assembly may comprise an inductor configured for heating a susceptor element. The inductor may at least partially surround the cavity. The inductor may inductively interact with the susceptor element to heat the susceptor element. The inductor may provide an alternating magnetic field in the cavity of the heater assembly. The inductor may be an induction coil.

[0115] The heater assembly may be used in pharmaceutical applications. The heater assembly may be used in a medical inhaler. The heater assembly may be used in an aerosol-generating device.

[0116] The invention further relates to an aerosol-generating device comprising the heater assembly as described herein.

[0117] The aerosol-generating device may comprise an extractor configured to remove one or more of the aerosol-generating article and aerosol-forming substrate from the device. The aerosol-generating device may comprise an insertor configured to insert one or more of the aerosol-generating article and aerosol-forming substrate into the device.

[0118] The cavity may comprise an air inlet. The cavity may comprise an air outlet.

[0119] The invention further relates to an aerosol-generating system comprising the aerosolgenerating device as described herein and an aerosol-forming substrate.

[0120] The system may comprise an aerosol-generating article. The aerosol-generating article may comprise the aerosol-forming substrate.

[0121] One or both of the aerosol-generating article and the aerosol-forming substrate may have a length of between 6 millimeters and 24 millimeters, preferably of between 8 millimeters and 20 millimeters, and more preferably of between 10 millimeters and 18 millimeters.

[0122] One or both of the aerosol-generating article and the aerosol-forming substrate may not comprise a filter element.

[0123] By providing an aerosol-generating article or aerosol-forming substrate which does not comprise a filter element, the efficiency of the aerosol delivery may be improved. By providing an aerosol-generating article or aerosol-forming substrate which does not comprise a filter element, the sustainability of the system may be improved.

[0124] The aerosol-generating article may comprise a susceptor element. The heater assembly may be configured to heat the susceptor element.

[0125] The aerosol-forming substrate may comprise a susceptor element. The heater assembly may comprise an inductor. The inductor may be configured to heat the susceptor element of the aerosol-generating article or aerosol-forming substrate when the article or substrate, respectively is inserted into the cavity of the heater assembly. The inductor may at least partially circumscribe the cavity. The inductor may be cylindrical, The inductor may be tubular. The inductor may be cuboid-shaped. The inductor may be an induction coil.

[0126] The aerosol-forming substrate may be a liquid aerosol-forming substrate.

[0127] The length of the aerosol-generating article may be of between 6 millimeters and 24 millimeters, preferably 8 millimeters and 20 millimeters and more preferably 10 millimeters and 18 millimeters.

[0128] As used herein, the terms ‘proximal’, ‘distal’, ‘downstream’ and ‘upstream’ are used to describe the relative positions of components, or portions of components, of the aerosolgenerating device and aerosol-generating system in relation to the direction in which a user draws on the aerosol-generating device during use thereof.

[0129] The aerosol-generating device may comprise a mouth end through which in use an aerosol exits the aerosol-generating device and is delivered to a user. The mouth end may also be referred to as the proximal end. In use, a user draws on the proximal or mouth end of the aerosol-generating device in order to inhale an aerosol generated by the aerosolgenerating device. Alternatively, a user may directly draw on an aerosol-generating article inserted into an opening at the proximal end of the aerosol-generating device. The opening at the proximal end may be the opening of the cavity. The cavity may be configured to receive the aerosol-generating article. The aerosol-generating device may comprise a distal end opposed to the proximal or mouth end. The proximal or mouth end of the aerosolgenerating device may also be referred to as the downstream end and the distal end of the aerosol-generating device may also be referred to as the upstream end. Components, or portions of components, of the aerosol-generating device and aerosol-generating system may be described as being upstream or downstream of one another based on their relative positions between the proximal, downstream or mouth end and the distal or upstream end of the aerosol-generating device.

[0130] As used herein, an ‘aerosol-generating device’ relates to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, for example part of a smoking article. An aerosolgenerating device may be a smoking device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is directly inhalable into a user’s lungs thorough the user's mouth. An aerosol-generating device may be a holder. The device may be an electrically heated smoking device. The aerosol-generating device may comprise a housing, electric circuitry, a power supply, and the heater assembly. As used herein with reference to the present invention, the term ‘smoking’ with reference to a device, article, system, substrate, or otherwise does not refer to conventional smoking in which an aerosol-forming substrate is fully or at least partially combusted. The aerosol-generating device of the present invention is arranged to heat the aerosol-forming substrate to a temperature below a combustion temperature of the aerosol-forming substrate, but at or above a temperature at which one or more volatile compounds of the aerosolforming substrate are released to form an inhalable aerosol.

[0131] The aerosol-generating device may comprise electric circuitry. The electric circuitry may comprise a microprocessor, which may be a programmable microprocessor. The microprocessor may be part of a controller. The electric circuitry may comprise further electronic components. The electric circuitry may be configured to regulate a supply of power to the heating element. Power may be supplied to the heating element continuously following activation of the aerosol-generating device or may be supplied intermittently, such as on a puff-by-puff basis. The power may be supplied to the heating element in the form of pulses of electrical current. The electric circuitry may be configured to monitor the electrical resistance of the heating element, and preferably to control the supply of power to the heating element dependent on the electrical resistance of the track of the heating element.

[0132] The aerosol-generating device may comprise a power supply, typically a battery, within a main body of the aerosol-generating device. The power supply may be connected to the electrical contacts. In one embodiment, the power supply is a Lithium-ion battery. Alternatively, the power supply may be a Nickel-metal hydride battery, a Nickel cadmium battery, or a Lithium based battery, for example a Lithium-Cobalt, a Lithium-lron-Phosphate, Lithium Titanate or a Lithium-Polymer battery. As an alternative, the power supply may be another form of charge storage device such as a capacitor. The power supply may require recharging and may have a capacity that enables to store enough energy for one or more usage experiences; for example, the power supply may have sufficient capacity to continuously generate aerosol for a period of around six minutes or for a period of a multiple of six minutes. In another example, the power supply may have sufficient capacity to provide a predetermined number of puffs or discrete activations of the heating element.

[0133] The cavity may be configured as a heating chamber. The cavity may have a shape corresponding to the shape of the aerosol-generating article to be received in the cavity. The cavity may have an inner diameter corresponding to the outer diameter of the aerosolgenerating article.

[0134] An airflow channel may run through the cavity. Ambient air may be drawn into the aerosol-generating device, into the cavity and towards the user through the airflow channel. Downstream of the cavity, a mouthpiece may be arranged or a user may directly draw on the aerosol-generating article. The airflow channel may extend through the mouthpiece. In any of the aspects of the disclosure, the electrically conductive track may comprise, preferably consist of an electrically resistive material. The resistively heated track may comprise, preferably consist of an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum platinum, gold and silver. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium- titaniumzirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, gold- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required.

[0135] The susceptor element may comprise a material that is capable of generating heat, when penetrated by an alternating magnetic field. If the susceptor element is conductive, then typically eddy currents are induced by the alternating magnetic field. If the susceptor element is magnetic, then typically another effect that contributes to the heating is commonly referred to hysteresis losses. Hysteresis losses occur mainly due to the movement of the magnetic domain blocks within the susceptor element, because the magnetic orientation of these will align with the magnetic induction field, which alternates. Another effect contributing to the hysteresis loss is when the magnetic domains will grow or shrink within the susceptor element. Commonly all these changes in the susceptor element that happen on a nano-scale or below are referred to as “hysteresis losses”, because they produce heat in the susceptor element. Hence, if the susceptor element is both magnetic and electrically conductive, both hysteresis losses and the generation of eddy currents will contribute to the heating of the susceptor element. If the susceptor element is magnetic, but not conductive, then hysteresis losses will be the only means by which the susceptor element will heat, when penetrated by an alternating magnetic field. According to the invention, the susceptor element may be electrically conductive or magnetic or both electrically conductive and magnetic. An alternating magnetic field generated by one or several inductors heat the susceptor element, which then transfers the heat to the aerosol-forming substrate, such that an aerosol is formed. The heat transfer may be mainly by conduction of heat.

[0136] The susceptor track may comprise a material that is capable of generating heat, when penetrated by an alternating magnetic field. If the susceptor track is conductive, then typically eddy currents are induced by the alternating magnetic field. If the susceptor track is magnetic, then typically another effect that contributes to the heating is commonly referred to hysteresis losses. Hysteresis losses occur mainly due to the movement of the magnetic domain blocks within the susceptor track, because the magnetic orientation of these will align with the magnetic induction field, which alternates. Another effect contributing to the hysteresis loss is when the magnetic domains will grow or shrink within the susceptor track. Commonly all these changes in the susceptor track that happen on a nano-scale or below are referred to as “hysteresis losses”, because they produce heat in the susceptor track. Hence, if the susceptor track is both magnetic and electrically conductive, both hysteresis losses and the generation of eddy currents will contribute to the heating of the susceptor track. If the susceptor track is magnetic, but not conductive, then hysteresis losses will be the only means by which the susceptor track will heat, when penetrated by an alternating magnetic field. According to the invention, the susceptor track may be electrically conductive or magnetic or both electrically conductive and magnetic. An alternating magnetic field generated by one or several inductors heat the susceptor track, which then transfers the heat to the aerosol-forming substrate, such that an aerosol is formed. The heat transfer may be mainly by conduction of heat, preferably via the sleeve.

[0137] As used herein, the term ‘aerosol-generating article’ refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. For example, an aerosol-generating article may be a smoking article that generates an aerosol that is directly inhalable into a user’s lungs through the user's mouth. An aerosolgenerating article may be disposable.

[0138] As used herein, the term ‘aerosol-forming substrate’ relates to a substrate capable of releasing one or more volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article.

[0139] The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosolforming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may comprise an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerine and propylene glycol.

[0140] The aerosol-forming substrate may be liquid aerosol-forming substrate. The liquid aerosol-forming substrate may comprise nicotine. The liquid aerosol-forming substrate may comprise a flavoring compound. The liquid aerosol-forming substrate may comprise an aerosol former, such as glycerine and propylene glycol. The aerosol-generating article may comprise a liquid storage portion. The liquid storage portion may be configured to hold liquid aerosol-forming substrate.

[0141] Below, there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0142] Example E1: A heater assembly for an aerosol-generating device, the heater assembly comprising: a cavity extending along a longitudinal axis between a first end and a second end, the first end being arranged for insertion of an aerosol-forming substrate into the cavity; and a heating element at least partially circumscribing the cavity, wherein the heating element comprises a single electrically conductive track comprising a plurality of parallelly extending elongate portions, wherein each elongate portion extends along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity, the single electrically conductive track further comprising a plurality of turns arranged to alternately interconnect neighboring ends of adjacent elongate portions.

[0143] Example E2: The heater assembly according to Example E1, wherein the heating element comprises two electrical contacts arranged at an end of the heating element adjacent the second end of the cavity, and wherein the electrical contacts are provided at opposing ends of the track.

[0144] Example E3: The heater assembly according to Example E1 or Example E2, wherein the heating element comprises at least 5 elongate portions, preferably at least 6 elongate portions, more preferably at least 7 elongate portions, more preferably at least 8 elongate portions, and more preferably at least 9 elongate portions.

[0145] Example E4: The heater assembly according to any of the preceding Examples, wherein each elongate portion extends along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

[0146] Example E5: The heater assembly according to any of the preceding Examples, wherein the elongate portions are unevenly spaced.

[0147] Example E6: The heater assembly according to Example E5, wherein a distance between adjacent elongate portions changes along a direction of the longitudinal axis of the cavity.

[0148] Example E7: The heater assembly according to Example E6, wherein the distance between adjacent elongate portions successively increases along the direction of the longitudinal axis of the cavity. Example E8: The heater assembly according to Example E7, wherein the distance between adjacent elongate portions successively increases by 2.5 percent, preferably 5 percent, more preferably 7.5 percent, and more preferably 10 percent along the direction of the longitudinal axis of the cavity.

[0149] Example E9: The heater assembly according to any of Examples E1 to E4, wherein at least some of the elongate portions, preferably all of the elongate portions, are evenly spaced.

[0150] Example E10: The heater assembly according to any of the preceding Examples, wherein the distance between adjacent elongate portions is between 0.6 millimeter and 2.7 millimeters.

[0151] Example E11: The heater assembly according to any of the preceding Examples, wherein each elongate portion has a width extending in the direction of the longitudinal axis of the cavity, and wherein two or more, preferably all elongate portions have different widths.

[0152] Example E12: The heater assembly according to Example E11, wherein the width of adjacent elongate portions successively increases along the direction of the longitudinal axis of the cavity.

[0153] Example E13: The heater assembly according to any of Examples E1 to E10, wherein each elongate portion has a width extending in the direction of the longitudinal axis of the cavity, and wherein the width of each elongate portion is the same.

[0154] Example E14: The heater assembly according to any of the preceding Examples, wherein each of the elongate portions has a thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity, and wherein two or more, preferably all elongate portions have different thicknesses.

[0155] Example E15: The heater assembly according to Example E14, wherein the thickness of adjacent elongate portions successively increases along the direction of the longitudinal axis of the cavity.

[0156] Example E16: The heater assembly according to any of Examples E1 to E13, wherein each of the elongate portions has a thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity, and wherein the thickness of each elongate portion is the same.

[0157] Example E17: The heater assembly according to any of the preceding Examples, wherein the heating element comprises a first region and a second region, wherein adjacent elongate portions in the first region are spaced apart by a first distance, and wherein adjacent elongate portions in the second region are spaced apart by a second distance.

[0158] Example E18: The heater assembly according to Example E17, wherein the first distance is the same as the second distance. Example E19: The heater assembly according to Example E17, wherein the first distance is different from the second distance.

[0159] Example E20: The heater assembly according to any of Examples E17 to E19, wherein the elongate portions of the first region have a first width extending in the direction of the longitudinal axis of the cavity, and wherein the elongate portions of the second region have a second width extending in the direction of the longitudinal axis of the cavity.

[0160] Example E21 : The heater assembly according to Example E20, wherein the first width is the same as the second width.

[0161] Example E22: The heater assembly according to Example E20, wherein the first width is different from the second width.

[0162] Example E23: The heater assembly according to any of Examples E17 to E22, wherein the elongate portions of the first region have a first thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity, and wherein the elongate portions of the second region have a second thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity.

[0163] Example E24: The heater assembly according to Example E23, wherein the first thickness is the same as the second thickness.

[0164] Example E25: The heater assembly according to Example E23, wherein the first thickness is different from the second thickness.

[0165] Example E26: The heater assembly according to any of Examples E17 to E25, wherein the first region and the second region are spaced apart by a third distance, and preferably wherein the third distance is different to one or both of the first distance and the second distance.

[0166] Example E27: The heater assembly according to any of Examples E17 to E26, wherein the first region and the second region are arranged at opposite ends of the heating element.

[0167] Example E28: The heater assembly according to any of the preceding Examples, wherein the heating element comprises a first base layer, and wherein the track is arranged on the first base layer.

[0168] Example E29: The heater assembly according to Example E29, wherein the heating element comprises a second base layer, wherein the track is configured to abut the first base layer and the second base layer, and wherein the track is arranged between the first base layer and the second base layer.

[0169] Example E30: The heater assembly according to any of the preceding Examples, wherein the heater assembly comprises an additional heating element, wherein the additional heating element comprises a susceptor element. Example E31: The heater assembly according to any of the preceding Examples, wherein the heater assembly comprises an inductor configured for heating a susceptor element.

[0170] Example E32: The heater assembly according to any of the preceding Examples, wherein the track is a serpentine track.

[0171] Example E33: The heater assembly according to any of the preceding Examples, wherein the track is configured as a continuous track.

[0172] Example E34: The heater assembly according to any of the preceding Examples, wherein the heating element is configured to be cylindrical, preferably tubular.

[0173] Example E35: The heater assembly according to any of the preceding Examples, wherein the heater assembly comprises a sleeve, wherein the sleeve is configured to at least partially circumscribe the cavity, and preferably wherein the sleeve is configured to be tubular.

[0174] Example E36: The heater assembly according to Example E35, wherein the heating element is configured to at least partially circumscribe the sleeve.

[0175] Example E37: The heater assembly according to Example E35 or Example E36, wherein the sleeve is made from a thermally conductive material.

[0176] Example E38: The heater assembly according to any of Examples E35 to E37, wherein the sleeve is made from one of stainless steel and aluminum.

[0177] Example E39: The heater assembly according to any of Examples E35 and E38, wherein a sidewall of the sleeve has a thickness of between 25 micrometers and 600 micrometers, preferably of between 50 micrometers and 400 micrometers, and more preferably of between 80 micrometers and 300 micrometers.

[0178] Example E40: The heater assembly according to any of the preceding Examples, wherein the cavity has a diameter of between 2 millimeters and 12 millimeters, preferably of between 4 millimeters and 10 millimeters, and more preferably of between 5 millimeters and 8 millimeters.

[0179] Example E41: The heater assembly according to any of the preceding Examples, wherein the heater assembly comprise two or more heating elements according to any of Examples E1 to 40.

[0180] Example E42: An aerosol-generating device comprising the heater assembly according to any of the preceding Examples.

[0181] Example E43: An aerosol-generating system comprising the aerosol-generating device according to Example E42 and an aerosol-forming substrate.

[0182] Example E44: The aerosol-generating system according to Example E43, wherein the system comprises an aerosol-generating article, and wherein the aerosol-generating article comprises the aerosol-forming substrate. Example E45: The aerosol-generating system according to Example E43 or Example E44, wherein one or both of the aerosol-generating article and the aerosol-forming substrate have a length of between 6 millimeters and 24 millimeters, preferably of between 8 millimeters and 20 millimeters, and more preferably of between 10 millimeters and 18 millimeters.

[0183] Example E46: The aerosol-generating system according to any of Examples E43 to E45, wherein one or both of the aerosol-generating article and the aerosol-forming substrate do not comprise a filter element.

[0184] Example E47: The aerosol-generating system according to any of Examples E43 to E46, wherein the aerosol-generating article comprises a susceptor element, and wherein the heater assembly is configured to heat the susceptor element.

[0185] Features described in relation to one embodiment may equally be applied to other embodiments of the invention.

[0186] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0187] Fig. 1 shows four heater assemblies of the present invention in Figs. 1A) to 1D);

[0188] Fig. 2 shows a schematic view of a heating element of the present invention; and

[0189] Fig. 3 shows a three-dimensional view of the heater assembly of the present invention.

[0190] Figs.1 A) to 1D) show four heater assemblies 100 of the present invention. Each of the heater assemblies 100 comprises a heating element 102. Each of the heater assemblies 100 comprises a cavity 104. Each of the four heating elements 102 fully circumscribes the cavity 104. The cavities 104 of the four heater assemblies 100 each have a longitudinal axis 106. The longitudinal axis 106 of the cavity 104 extends between a first end 108 of the cavity 104 and a second end 110 of the cavity 104. The first end 108 is a proximal end of the cavity 104. The first end 108 is configured for insertion of an aerosol-forming substrate into the cavity 104. The second end 110 is a distal end of the cavity 104.

[0191] The heating element 102 has a first end. The first end of the heating element 102 is a proximal end of the heating element 102. The first end of the heating element 102 is arranged at the first end 108 of the cavity 104. The heating element 102 has a second end. The second end of the heating element 102 is a distal end of the heating element 102. The second end of the heating element 102 is arranged at the second end 110 of the cavity 104.

[0192] Each of the four heating elements 102 comprises multiple elongate portions 112 and multiple turns (not shown). The turns interconnect adjacent elongate portions 112. Each of the four heating elements 102 is tubular with a circular cross-section. The elongate portions 112 and turns are arranged on a first base layer 114 to form at least part of an electrically conductive track. The elongate portions 112 and turns are arranged on the outer surface of the first base layer 114. In each of the four heating elements 102, each elongate portion 112 is arranged within a plane substantially perpendicular to the longitudinal axis 106 of the cavity 104. The four heater assemblies 100 of Fig. 1A) to 1D) differ from each other in the arrangement and configuration of the elongate portions 112.

[0193] The heating element 102 of Fig. 1A) comprises a plurality of elongate portions 112. The heating element 102 comprises nine elongate portions 112. The elongate portions are arranged evenly spaced. The elongate portions each have a same width extending in the direction of the longitudinal axis 106 of the cavity 104. The elongate portions each have a same thickness extending in the plane substantially perpendicular to the longitudinal axis 106 of the cavity 104.

[0194] The heating element 102 of Fig. 1B) comprises a first region 116 of the elongate portions 112 and a second region 118 of the elongate portions 112. The first region 116 is arranged at the first end 108 of the cavity 104. The second region 118 is arranged at the second end 110 of the cavity 104. The elongate portions 112 each have a same width extending in the direction of the longitudinal axis 106 of the cavity 104. The elongate portions each have a same thickness extending in the plane substantially perpendicular to the longitudinal axis 106 of the cavity 104. The elongate portions 112 in the first region 116 are spaced apart by a first distance. The elongate portions 112 in the second region 118 of are spaced apart by a second distance. In the embodiment shown, the first distance is the same as the second distance.

[0195] The first region 116 and the second region 118 are separated by a region 120 void of elongate portions. The region 120 void of elongate portions extends across a third distance. The first region 116 and the second region 118 are arranged at opposite ends of the heating element. The first region 116 and the second region 118 are connected by a turn (not shown) extending across the region 120 void of elongate portions along the direction of the longitudinal axis of the cavity.

[0196] By providing separate regions 116 and 118 of elongate portions 112, an aerosolforming substrate inserted into the cavity 104 may be heated at specific portions along the length of the aerosol-forming substrate. In the embodiment shown, the aerosol-forming substrate may be heated in the portions adjacent to the first region 116 and the second region 118. In this way, the user experience may be improved.

[0197] The heating element 102 of Fig. 1C) comprises elongate portions 112 which are unevenly spaced. The distance between adjacent elongate portions 112 decreases towards the second end 110 of the heating element 102. The elongate portions 112 each have a same width extending in the direction of the longitudinal axis 106 of the cavity 104. The elongate portions 112 each have a same thickness extending in the plane substantially perpendicular to the longitudinal axis 106 of the cavity 104.

[0198] By providing the heating element 102 with elongated portions 112 spaced at varying distances, the heating profile delivered by the heating element 102 may be adjusted along the direction of the longitudinal axis 106. The distance between adjacent elongate portions may be decreased to provide a more intense heating profile to an adjacent portion of an aerosol-forming substrate inserted into the cavity 104. The distance between adjacent elongate portions may be increased to provide a less intense heating profile to an adjacent portion of the aerosol-forming substrate inserted into the cavity 104. In the embodiment shown, the portion of the aerosol-forming substrate inserted into cavity 104 which is adjacent to the second end 110 may be heated more intensely than regions of the aerosol-forming substrate adjacent to the first end 108 as the distance between adjacent elongate portions at the second end 110 is smaller than at the first end 108. By varying the spacing between adjacent elongate portions 112, heating profiles varying along the length of the heating element may be delivered to an inserted aerosol-forming substrate. The user experience may be improved.

[0199] The heating element 102 of Fig. 1 D) comprises elongate portions 112 having a variable width extending in the direction of the longitudinal axis 106 of the cavity 104. The width of the elongate portions increases towards the first end 108 of the cavity 104. The distance between adjacent portions decreases towards the first end 108 of the cavity 104. The elongate portions 112 each have a same thickness extending in the plane substantially perpendicular to the longitudinal axis 106 of the cavity 104.

[0200] By varying the width of the elongate portions, the heating profile delivered by the heating element may be adjusted. In the embodiment shown, portions of an aerosol-forming substrate inserted into the cavity, which are arranged at the first end 108 of the heating element 102 may be more intensely heated than portions arranged at the second 110 of the heating element 102 because the width of the elongate portions at the first end 108 of the heating element 102 is larger than the width of the elongate portions at the second end 110 of the heating element 102 and because the distance between adjacent portions at the first end 102 is smaller than towards the second end 110.

[0201] Fig. 2 shows a schematic view of the heating element 102 of the heater assembly 100 of the invention. The heating element 102 comprises the first base layer 114. The heating element 102 comprises multiple elongate portions 112. The elongate portions 112 are arranged on the first base layer 114. The heating element 102 comprises multiple turns 122. The turns 122 are arranged to alternately interconnect neighboring ends of adjacent elongate portions 112. The heating element 102 comprises connecting portions 124. The connecting portions are arranged parallel to the longitudinal axis 106 of the cavity (not shown) of the heater assembly 100.

[0202] The elongate portions 112, the turns 122 and the connecting portions 124 form a single electrically conductive track. The electrically conductive track is arranged in a serpentine pattern.

[0203] The heating element comprises two electrical contacts 126. The electrical contacts 126 are arranged at the second end 110 of the cavity (not shown). One end of the track is arranged to be in contact with one of the electrical contacts 126. The other end of the track is arranged to be in contact with the other electrical contact 126. The electrical contacts 126 may be connected to a power supply of an aerosol-generating device which comprises the heating element. Power may be supplied through the electrical contacts 126 to the track to heat the track.

[0204] Adjacent elongate portions 112 are spaced apart by distance 128. The distance 128 is the same for all adjacent elongate portions. The elongate portions 112 have a width 130 extending in the direction of the longitudinal axis 106 of the cavity 104. The width of all the elongate portions 112 is the same.

[0205] Fig. 3 shows the heater assembly 100 of the invention. The heater assembly 100 comprises heating element 102 and cavity 104. The heater assembly essentially corresponds to the heating element of Fig. 3 rolled up around the longitudinal axis 106 to form the tubular heating element 102 of Fig. 3. The track including the elongate portions 112, turns 122 and connecting portions 124 is arranged on an outer surface of the first base layer 114. The heating element 102 is arranged lateral of the cavity 104. The heating 102 element fully circumscribes the cavity 104.

[0206] Each of the elongate portions 112 at least partially circumscribes the cavity 104. Each elongate portion is arranged at least partially around the cavity 104. The turns 122 interconnect adjacent elongate portions 112.

[0207] The heating element 100 comprises two electrical contacts 126. The electrical contacts 126 are arranged next to each other. The electric contacts 126 are arranged at the second end 112 of the heating element 100. The electrical contacts 126 are each connected to an end of the electrically conductive track

[0208] The heater assembly 100 comprises a sleeve 128. The heating element 102 fully circumscribes the sleeve 128. The sleeve 128 fully circumscribes the cavity 104. The sleeve 128 lines the cavity 104. The sleeve 128 is made from a thermally conductive material, such as a aluminium or stainless steel. An inner surface of the first base layer 114 may be in contact with the sleeve 128. The first base layer 114 may be made from an electrically insulating material. An aerosol-forming substrate may be inserted into the cavity 104 via the first end 108 of the cavity. Power may be provided to the track via a power supply connected to the electrical contacts 126. The heated track may heat the sleeve 128. The heated sleeve may heat the inserted aerosol-forming substrate. The elongate portions 112 of the heating element 102 of Fig. 3 are evenly spaced.

[0209] The width of each elongate portion 112 is the same. The thickness of each elongate portion 112 is the same. The heating element 102 of Fig. 3 may provide a uniform heating profile to the aerosol-forming substrate.

Claims

CLAIMS1. A heater assembly for an aerosol-generating device, the heater assembly comprising: a cavity extending along a longitudinal axis between a first end and a second end, the first end being arranged for insertion of an aerosol-forming substrate into the cavity; and a heating element at least partially circumscribing the cavity, wherein the heating element comprises a single electrically conductive track comprising a plurality of parallelly extending elongate portions, wherein each elongate portion extends along at least 50 percent of a circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity, the single electrically conductive track further comprising a plurality of turns arranged to alternately interconnect neighboring ends of adjacent elongate portions.

2. The heater assembly according to claim 1, wherein the heating element comprises two electrical contacts arranged at an end of the heating element adjacent the second end of the cavity, and wherein the electrical contacts are provided at opposing ends of the track.

3. The heater assembly according to claim 1 or claim 2, wherein the heating element comprises at least 5 elongate portions, preferably at least 6 elongate portions, more preferably at least 7 elongate portions, more preferably at least 8 elongate portions, and more preferably at least 9 elongate portions.

4. The heater assembly according to any of the preceding claims, wherein each elongate portion extends along at least 60 percent of the circumference of the cavity, preferably along at least 70 percent of the circumference of the cavity, more preferably along at least 80 percent of the circumference of the cavity, and more preferably along at least 90 percent of the circumference of the cavity.

5. The heater assembly according to any of the preceding claims, wherein the elongate portions are unevenly spaced.

6. The heater assembly according to any of claims 1 to 4, wherein at least some of the elongate portions, preferably all of the elongate portions, are evenly spaced.

7. The heater assembly according to any of the preceding claims, wherein each elongate portion has a width extending in the direction of the longitudinal axis of the cavity, and wherein two or more, preferably all elongate portions have different widths.

8. The heater assembly according to any of the preceding claims, wherein each of the elongate portions has a thickness extending in the plane substantially perpendicular to the longitudinal axis of the cavity, and wherein two or more, preferably all elongate portions have different thicknesses.

9. The heater assembly according to any of of the preceding claims, wherein the heating element comprises a first region and a second region, wherein adjacent elongate portions in the first region are spaced apart by a first distance, and wherein adjacent elongate portions in the second region are spaced apart by a second distance.

10. The heater assembly according to claim 9, wherein the first region and the second region are spaced apart by a third distance, and preferably wherein the third distance is different to one or both of the first distance and the second distance.

11. The heater assembly according to claim 9 or claim 10, wherein the first region and the second region are arranged at opposite ends of the heating element.

12. The heater assembly according to any of the preceding claims, wherein the heating element comprises a first base layer, and wherein the track is arranged on the first base layer.

13. The heater assembly according to any of the preceding claims, wherein the heater assembly comprises a sleeve, wherein the sleeve is configured to at least partially circumscribe the cavity, and preferably wherein the sleeve is configured to be tubular.

14. The heater assembly according to any of the preceding claims, wherein a width of each of the elongate portions is constant along the extent of the elongate portion.

15. The heater assembly according to any of the preceding claims, wherein each elongate portion consists of electrically resistive material being configured as a geodesic extending along at least 50 percent of the circumference of the cavity within a plane substantially perpendicular to the longitudinal axis of the cavity.

16. An aerosol-generating device comprising the heater assembly according to any of the preceding claims.

17. An aerosol-generating system comprising the aerosol-generating device according to claim 16 and an aerosol-forming substrate.

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