Aerosol-generating device

Abstract

Aerosol-generating device (10) comprising a cavity (14) configured to receive aerosol-forming substrate (22). The cavity comprises protruding elements (18) extending in a radial direction. Airflow channels (40) are formed in between the protruding elements. The protruding elements comprise at least part of heating elements. Aerosol-generating system comprising the aerosol-generating device and an aerosol-generating article (12) comprising aerosol-forming substrate. Method for manufacturing the protruding elements.

Description

[0001] AEROSOL-GENERATING DEVICE

[0002] The present invention relates to an aerosol-generating device.

[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 volatilised without burning the aerosolforming substrate. 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 aerosolgenerating 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 for heating the aerosolforming substrate once the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device.

[0004] It would be desirable to have an aerosol-generating device with improved airflow. It would be desirable to have an aerosol-generating device with improved preheating of ambient air. It would be desirable to have an aerosol-generating device with improved heating of ambient air. It would be desirable to have an aerosol-generating device with improved resistance to draw.

[0005] According to an embodiment of the invention there is provided an aerosol-generating device that may comprise a cavity configured to receive aerosol-forming substrate. The cavity may comprise protruding elements extending in a radial direction. Airflow channels may be formed in between the protruding elements. The protruding elements may comprise heating elements.

[0006] According to an embodiment of the invention there is provided an aerosol-generating device comprising a cavity configured to receive aerosol-forming substrate. The cavity comprises protruding elements extending in a radial direction. Airflow channels are formed in between the protruding elements. The protruding elements comprise heating elements.

[0007] Providing the protruding elements with heating elements may facilitate the protruding elements having a double functionality. The first functionality of the protruding elements may be to create the airflow channels in between the protruding elements. The second functionality of the protruding elements may be one or both of preheating air drawn into the aerosolgenerating device and heating the aerosol-forming substrate.

[0008] Providing the protruding elements with the heating elements may be particularly beneficial due to the spatial arrangement of the protruding elements. As will be described in more detail below, the protruding elements may face the inner of the cavity and may directly contact an aerosol-generating article received in the cavity. Providing the protruding elements with the heating elements may thus mean that the heating elements may come into proximity or direct contact with the aerosol-generating article. This may beneficial for heating the aerosolforming substrate of the aerosol-generating article. Additionally or alternatively, the heating elements are adjacent the airflow channels to enable preheating of the air being drawn through the airflow channel.

[0009] 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, a heating chamber and a heating element.

[0010] The cavity of the aerosol-generating device may have an open end into which the aerosol-generating article is inserted. The open end may be a proximal end. The cavity may have a closed end opposite the open end. The closed end may be the base of the cavity. The base of the cavity may be circular. The base of the cavity may be arranged upstream of the cavity. The open end may be arranged downstream of the cavity. The cavity may have an elongate extension. The cavity may have a longitudinal central axis. A longitudinal direction may be the direction extending between the open and closed ends along the longitudinal central axis. The longitudinal central axis of the cavity may be parallel to or identical to the longitudinal axis of the aerosol-generating device.

[0011] The cavity may be configured as a heating chamber. The cavity may have a cylindrical shape. The cavity may have a hollow cylindrical shape. 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 a circular cross-section. The cavity may have an elliptical or rectangular crosssection. The cavity may have an inner diameter corresponding to the outer diameter of the aerosol-generating article.

[0012] The protruding elements protruding in a lateral direction may also be referred to as the protruding elements protruding in a radial direction. This direction may be perpendicular to the longitudinal axis of one or both of the cavity and the aerosol-generating device. The protruding elements may have an elongate extension. The protruding elements may have an elongate extension parallel to the longitudinal axis of the cavity.

[0013] The airflow channels may be formed between individual protruding elements. One airflow channel may be formed between two protruding elements. The number of airflow channels may be identical to the number of protruding elements.

[0014] The protruding elements may be uniformly arranged surrounding the cavity. The protruding elements may have a central longitudinal axis around which the individual protruding elements are arranged. The protruding elements may each have the same distance towards the central longitudinal axis. The central longitudinal axis of the protruding elements may be identical to the longitudinal axis of the cavity.

[0015] The protruding elements together may have a tubular arrangement around the central longitudinal axis of the protruding elements.

[0016] The inner diameter of the inner of the cavity may be defined by the distance between opposite protruding elements. In other words, the protruding elements may be arranged around the outer periphery of the inner of the cavity.

[0017] The protruding elements may be configured as ribs. The ribs may have a length considerably longer than the width of the ribs. The length of the ribs may be measured parallel to the longitudinal axis of the cavity. The width of the ribs may be measured perpendicular to the longitudinal axis of the cavity. The width of the ribs may be measured in a lateral direction. The length of the ribs may be at least two times, preferably at least three times, preferably at least four times, most preferably at least five times longer than the width of the ribs.

[0018] The ribs may have a thickness considerably smaller than either the length of the ribs and the width of the ribs. The thickness of the ribs may be measured in a tangential direction with respect to the longitudinal axis of the cavity and with respect to the tubular arrangement of the protruding elements around the longitudinal axis of the cavity. The thickness of the ribs may be smaller by a factor of at least two, preferably by a factor of at least three, preferably by a factor of at least four, most preferably by a factor of at least five, with respect to one or both of the length of the ribs and the width of the ribs.

[0019] The protruding elements may be arranged on an inner sidewall of the cavity. The protruding elements may be mounted or attached to the inner sidewall of the cavity. Alternatively, the protruding elements may be integrally formed with the cavity. The rest of the cavity, i.e. the non-protruding elements part of the cavity, may be tubular. The cavity may form a structural support for the protruding elements. The protruding elements may extend radially inwards. In other words, the protruding elements may extend from the cavity wall radially towards the longitudinal axis of the cavity.

[0020] The protruding elements may each comprise a radially inwards facing contacting surface configured for contacting an aerosol generating article received in the cavity.

[0021] The contacting surface may be smooth. Alternatively, the contacting surface may have a friction increasing surface structure increasing friction between the contacting surface and the received aerosol-generating article to assist a holding action of the aerosol-generating article within the cavity.

[0022] The protruding elements may comprise at least part of a sensing arrangement.

[0023] The contacting surface may be curved, for instance, in order to match the shape of the outer periphery of the aerosol-generating article. The contacting surface may be curved so as to form a concave or convex surface for contacting the aerosol generating article. This may improve contact between the contacting surface and the aerosol-generating article. Improved contact between the contacting surface and the aerosol-generating article may be beneficial for one or both of a sensing operation of the sensing arrangement and heating of the heating elements. As will be described in more detail below, the contacting surface may comprise or may be part of or may form the sensing arrangement. A matching shape between the contacting surface and the outer periphery of the aerosol-generating article may further prevent damage to the aerosol-generating article within the cavity.

[0024] The radially inwards facing contacting surfaces may be configured to retain the aerosolgenerating article comprising the aerosol-forming substrate in the cavity.

[0025] The radially inwards facing contacting surfaces may comprise a coating, preferably a gold coating. The coating may be electrically conductive. The coating may improve electrical contact between the outer periphery of the aerosol-generating article and the sensing arrangement.

[0026] The protruding elements comprising the radially inwards facing contacting surfaces may be configured as electrodes. The electrodes may be part of the sensing arrangement. The electrodes may be electrically connected with the sensing arrangement. The coating may be configured as the electrodes. As will be described in more detail below, the electrodes may enable measurement of an electrical property (e.g. resistance) of one or more corresponding identification elements arranged on the outer periphery of the aerosol-generating article and may thus enable e.g. an identification of the aerosol-generating article or of the type of received aerosol-generating article. Additionally or alternatively, the electrodes may be configured to measure a temperature of the outer periphery of the aerosol-generating article, preferably by a measurement of the electrical resistance of the electrodes. The electrical resistance of the electrodes may change as a function of the temperature of the respective electrode so that the measurement of the electrical resistance of an electrode may enable a determination of the temperature of the electrode. Due to the contact of the electrode with the outer periphery of the aerosol-generating article. The temperature of the electrode may be indicative of the temperature of the outer periphery of the aerosol-generating article.

[0027] The protruding elements comprising the radially inwards facing contacting surfaces may be configured as capacitive sensing elements, preferably having a dielectric constant different from ambient air. The contacting surfaces may be configured as the capacitive sensing elements. The capacitive sensing elements may facilitate a capacitive coupling between the sensing arrangement and the outer periphery of the aerosol-generating article. As will be described in more detail below, the outer periphery of the aerosol-generating article may comprise one or more corresponding identification elements enabling e.g. an identification of the aerosol-generating article or of the type of received aerosol-generating article.

[0028] Only one of the protruding elements may comprise a part of the sensing arrangement. Alternatively, more than one but not all the protruding elements may comprise a part of the sensing arrangement. As a further alternative, each of the protruding elements may comprise a part of the sensing arrangement.

[0029] A distance between radially inwards facing contacting surfaces of the protruding elements may decrease in a distal direction.

[0030] This may facilitate a secure holding of the aerosol-generating article when the aerosolgenerating article is received in the cavity. Particularly, the holding action acted upon the aerosol-generating article may increase the further the aerosol-generating article is pushed into the cavity due to the decreasing distance between the protruding elements. In other words, the aerosol-generating article may be sandwiched between the protruding elements and thereby securely held by the protruding elements. The decreasing distance between the protruding elements may mean that the aerosol-generating article can be easily inserted into the cavity while, during the further insertion of the aerosol-generating article, the aerosolgenerating article can be securely held between the protruding elements and thus within the cavity.

[0031] The distance between radially inwards facing contacting surfaces of opposite protruding elements may decrease from a distance larger than an outer diameter of the aerosol-generating article to a distance corresponding to or smaller than the outer diameter of the aerosol-generating article to assist holding of the aerosol-generating article in the cavity.

[0032] In addition, or alternatively, at least a part of one or more of the protrusions (e.g., one or more the electrodes) may be biased inwardly in the radial direction. This may assist in gripping the aerosol-generating article.

[0033] The distance between opposite radially inwards facing contacting surfaces of the protruding elements may be between 5mm and 9mm, preferably between 6mm and 8mm, more preferably between 6.5mm and 7.2mm.

[0034] A distance between opposite protruding elements may be between 0.5mm and 2.0mm, preferably between 0.7mm and 1.6mm, more preferably between 0.9mm and 1.3mm.

[0035] A width of one or more or all protruding elements may be between 0.2mm and 1.6mm, preferably between 0.4mm and 1.3mm, more preferably between 0.6mm and 1.0mm. Proximal portions of the radially inwards facing contacting surfaces may be chamfered or curved to assist insertion of the aerosol-generating article.

[0036] The proximal portions of the radially inwards facing contacting surfaces may form an entrance to the cavity. This entrance may thus be configured such that an aerosol-generating article can easily be inserted into the cavity. In other words, the holding action of the aerosolgenerating article within the cavity may be exerted by the contacting surfaces of the protruding elements distal from the entrance of the cavity. The proximal portions of the radial inwards facing contacting surfaces may not exert a holding action upon the aerosol-generating article. The proximal portions of the radial inwards facing contacting surfaces may form a guiding entrance for insertion of the aerosol-generating article into the cavity.

[0037] Longitudinal side surfaces of the protruding elements may have a positive draft angle.

[0038] The longitudinal side surfaces of the protruding elements may be abutting the contacting surfaces of the protruding elements. The longitudinal side surfaces of the protruding elements may connect the contacting surfaces of the protruding elements with the cavity wall. The longitudinal side surfaces of the protruding elements may connect the contacting surfaces of the protruding elements with the base of the protruding elements.

[0039] The positive draft angle may assist in manufacturing of the protruding elements by injection moulding.

[0040] The positive draft angle may be between 0.5° and 10°, preferably between 1° and 5°, more preferably between 1.5° and 2.5°. The aerosol-generating device may further comprise an air inlet arranged adjacent a proximal end of the cavity.

[0041] The air inlet may be arranged at the proximal end of the cavity. The air inlet may be ring-shaped. The air inlet may be arranged adjacent and inside a proximal end of the cavity. The air inlet may enable drawing of ambient air into the aerosol-generating device, particularly into the cavity of the aerosol-generating device, via the proximal end of the device.

[0042] The aerosol-generating device may be free of further air inlets. Particularly, no apertures or other air inlets may be provided at the base of the cavity, at sidewalls of a housing of the aerosol-generating device or at a distal end of the aerosol-generating device.

[0043] The airflow channels may be fluidly connected with the air inlet. The airflow channels may be arranged downstream of the air inlet. The airflow channels may be arranged distal of the air inlet.

[0044] The airflow channels may be arranged between the inner sidewall of the cavity and the outer periphery of the aerosol-generating article, when the aerosol-generating article is received in the cavity. Further, opposite sidewalls of the sidewall channels may be provided by the protruding elements.

[0045] The airflow channels may comprise a U-turn adjacent the base of the cavity such that ambient air is drawn into the cavity through the air inlet and further the airflow channels and subsequently enters the inner of the aerosol-generating article through a distal end face of the aerosol-generating article. To facilitate this, the outer periphery of the aerosol-generating article may be fluid impermeable or may at least reduce airflow through the outer periphery. The only relevant airflow into the aerosol-generating article apart from the airflow through the distal end face may be through perforations provided at a ventilation zone of the aerosolgenerating article.

[0046] The protruding elements may be arranged on an outer periphery of the cavity.

[0047] This is an alternative configuration to providing the protruding elements on an inner sidewall of the cavity. In this alternative configuration, the inner sidewall of the cavity is preferably smooth so that the aerosol-generating article sits flush against the inner sidewall of the cavity.

[0048] The protruding elements may extend radially outwards. The protruding elements may be mounted or attached to the outer periphery of the cavity. The protruding elements may alternatively be integrally formed with the outer periphery of the cavity.

[0049] An inner sidewall of the cavity may be smooth to enable a tight fit between the cavity and a received aerosol-generating article.

[0050] The air inlet may be formed between an outer periphery of the cavity and an outer periphery of a housing of the aerosol-generating device. In other words, in this configuration, the air inlet may match the different arrangement of the airflow channels by being arranged outside of the cavity.

[0051] The protruding elements may be elongate. The shape of the protruding elements may be similar or identical to the ones described above with respect to the first concert configuration which the protruding elements are arranged protruding radially inwards from the cavity. Exemplarily, the protruding elements may have positive draft angles to assist manufacturing of the protruding elements via injection moulding.

[0052] The protruding elements may be made from an electrically conductive material.

[0053] The protruding elements may be made from stainless steel, preferably from stainless steel 316L.

[0054] At least 6, preferably at least 8, preferably at least 10, most preferably at least 12, protruding elements may be provided.

[0055] The number of protruding elements may be between 6 and 18, preferably between 8 and 16, more preferably between 10 and 14, most preferably 12.

[0056] This number of protruding elements may facilitate a secure holding of the aerosolgenerating article within the cavity.

[0057] The airflow channels may extend to a base of the cavity.

[0058] The airflow channels may comprise a U-shaped turn at the base of the cavity.

[0059] The protruding elements may be arranged at a proximal portion of the cavity. Arranging the protruding elements at a proximal portion of the cavity may assist in holding the aerosolgenerating article at the proximal portion of the cavity. This may prevent wobbling of the aerosol-generating article at the proximal portion of the cavity which may be unwanted.

[0060] The cavity may comprise retaining elements. The retaining elements may be configured to hold the aerosol-generating article within the cavity. This functionality of the retaining elements may be similar to the herein described functionality of the protruding elements of holding the aerosol-generating article. The retaining elements may complement the protruding elements to, together, securely hold the aerosol-generating article within the cavity. Alternatively, the retaining elements may solely hold the aerosol-generating article within the cavity.

[0061] The retaining elements may comprise retaining protrusions configured to retain the aerosol-generating article when the aerosol-generating article is received in the cavity. The retaining protrusions may contact the aerosol-generating article, when the aerosol-generating article is received in the cavity. The reaching protrusions may comprise contact surfaces configured to contact the aerosol-generating article. The contact surfaces may have a shape matching the shape of the outer periphery of the aerosol-generating article. Opposite contact surfaces may be distanced such that the distance between opposite contact surfaces is similar or slightly smaller than the outer diameter of the aerosol-generating article.

[0062] The retaining protrusions may extend radially inwards from an inner sidewall of the cavity.

[0063] The retaining protrusions may be arranged at a distal portion of the cavity. As described herein, the protruding elements may be arranged at a proximal portion of the cavity. Hence, the aerosol-generating article may be securely held within the cavity by contacting the protruding elements at the proximal portion of the cavity and by contacting the retaining protrusions at the distal portion of the cavity.

[0064] The aerosol-generating device may further comprise a heating element configured to heat aerosol-forming substrate received in the cavity. The heating element may also be denoted as main heating element of the aerosol-generating device. The main heating element of the aerosol-generating device may be different from the heating elements of the protruding elements. The main heating element of the aerosol-generating device may be configured to heat the aerosol-forming substrate of the aerosol-generating article while the heating elements of the protruding elements may be configured to preheat ambient air being drawn into the aerosol-generating device via the air inlet.

[0065] The heating element may be configured as an inductive heating element. The inductive heating element may comprise an induction coil. The induction coil may be a helical induction coil. The induction coil may be arranged around the cavity.

[0066] The heating element may be arranged distal of the protruding elements. The heating element may be arranged at least partly, preferably fully, surrounding the cavity.

[0067] The heating element may be arranged between the protruding elements and the retaining protrusions.

[0068] The heating element may comprise a susceptor. The susceptor may be tubular. The tubular susceptor may be arranged between the proximal protruding elements and the distal retaining protrusions. Alternatively, and preferred, the susceptor may be arranged within the aerosol-generating article. Exemplarily, the susceptor may be provided as a strip within the aerosol-generating article. In this case, the heating element of the aerosol-generating device preferably comprises an induction coil arranged surrounding the portion of the cavity the aerosol-generating article having the susceptor is arranged in when the aerosol-generating article is received in the cavity.

[0069] As described herein, the protruding elements preferably comprise heating elements.

[0070] The heating elements of the protruding elements may be provided in addition or alternatively to the (main) heating element of the aerosol-generating device. The heating elements of the protruding elements may optimally transmit heat into the aerosol-generating device due to the abutting contact between the protruding elements and the outer periphery of the aerosol-generating article when the aerosol-generating article is received in the cavity. Alternatively, the heating elements of the protruding elements may be configured to preheat the ambient air being drawn through the airflow channels adjacent the protruding elements. This preheating of the air flowing through the airflow channels may improve aerosol generation when this pre-warmed air enters the aerosol-generating article and is subsequently heated by the main heating element of the aerosol-generating device.

[0071] The heating elements of the protruding elements may be electrically resistive heating elements.

[0072] The heating elements of the protruding elements may be formed at the contacting surfaces of the protruding elements. The contacting surfaces of the protruding elements may be configured as heating elements. Exemplarily, the contacting surfaces of the protruding elements may be resistive heaters. To this end, the contacting surfaces of the protruding elements may be made from an electrically conductive material such as metal.

[0073] Alternatively, the contacting surfaces of the protruding elements may be configured as susceptors to enable induction heating. An induction coil may be arranged surrounding the cavity and the protruding elements to create eddy currents within the susceptor so as to facilitate heating of the susceptors.

[0074] The heating elements may be configured to preheat ambient air being drawn through the air inlet and into the airflow channels adjacent the protruding elements.

[0075] If preheating of ambient air is the main goal or sole purpose of the heating elements of the protruding elements, the heating elements of the protruding elements may be arranged at the sidewalls of the protruding elements directly abutting the airflow channel instead of arranging the heating elements of the protruding elements at the contacting surfaces of the protruding elements.

[0076] As a further alternative, heating elements may be provided at the contacting surfaces of the protruding elements in order to heat the aerosol-generating article and heating elements may be arranged at the sidewalls of the protruding elements in order to preheat ambient air being drawn through the airflow channels.

[0077] The heating elements may comprise susceptor material.

[0078] The aerosol-generating device further comprises an induction coil arranged surrounding the heating elements.

[0079] The heating elements may be configured as resistive heating elements.

[0080] The sensing arrangement may be configured as an article sensor.

[0081] The article sensor may be configured to detect the presence of an aerosol-generating article. As described herein, a particularly preferred embodiment is that the contacting surfaces of the protruding elements are configured as electrodes or capacitive sensing elements directly contacting the outer periphery of the aerosol-generating article when the aerosol-generating article is received in the cavity. The outer periphery of the aerosol-generating article may comprise one or more identification elements that are arranged to directly contact the electrodes of the protruding elements. The electrodes of the protruding elements can then measure an electrical resistance of the identification element of the aerosol-generating article which may be indicative of the presence of an aerosol-generating article and potentially the type of an inserted aerosol-generating article. If the identification element of the aerosolgenerating article is provided as a capacitive marker, this capacitive marker may be arranged in direct contact or adjacent or close to or passing the capacitive sensing elements of the sensing arrangement of the aerosol-generating device thereby enabling detection of the presence of an aerosol-generating article and potentially of the type of aerosol-generating article. The sensing arrangement may be configured to detect a type of aerosol-generating article received in the cavity.

[0082] The sensing arrangement may be configured to detect the presence of an aerosolgenerating article in the cavity.

[0083] The sensing arrangement of the protruding elements may be arranged adjacent the heating elements of the protruding elements. Both of the sensing arrangement of the protruding elements and the heating elements of the protruding elements may be arranged on the contacting surfaces of the respective protruding elements.

[0084] The protruding elements may have a varying thickness. One or more of the protruding elements may have a thickness varying from the thickness of one or more different protruding elements. Alternatively or additionally, one or more of the protruding elements have a varying thickness along the longitudinal length of the air respective protruding element.

[0085] The airflow channels may have a total cross-sectional area of between 0,8 mm2and 4,0 mm2.

[0086] The protruding elements may have a trapezoidal shape. The protruding elements may have a trapezoidal cross-section. The wider ends of the protruding elements may form bases of the protruding elements. The narrower ends of the protruding elements may form the contacting surfaces of the protruding elements.

[0087] The protruding elements may be made by metal stamping, metal bending or metal plating.

[0088] Metal stamping is a manufacturing process where a metal foil is pressed in one shot to obtain the proper shape, for example the shape of the protruding elements. Similar to metal stamping, metal bending is a process by which metal can be deformed when applying force to the subject, which causes it to bend at an angle and form the anticipated shape, for example the shape of the protruding elements. Metal stamping and metal bending are the preferred manufacturing processes for manufacturing the protruding elements. Metal plating is a chemical manufacturing process where a plastic component is immerged in a chemical bath, forming a metal thin layer of coating.

[0089] The manufacturing may comprise the following process steps: metal stamping the protruding elements with a frame having two ribbons on the side, each of them comprising holes; during the assembly step, the whole frame is moving linearly on equipment dedicated to the assembly; thanks to the presence of the holes, the positions of the parts (mainly of the protruding elements) is better controlled; furthermore, the holes are configured such to be synchronized with the speed of the equipment, once the protruding elements are in position, a vertical cutter is operating to detach the protruding elements from the frame; finally, a highspeed mechanical “finger” pushes the protruding elements within a cavity of a tubular component that can subsequently act as the cavity of the aerosol-generating device.

[0090] The invention further relates to an aerosol-generating system comprising the aerosolgenerating device according to any of the preceding claims and an aerosol-generating article comprising aerosol-forming substrate.

[0091] The aerosol-generating article may comprise an identification element.

[0092] The identification element may be arranged on or adjacent an outer periphery of the aerosol-generating article.

[0093] The identification element may be a metal strip.

[0094] The identification element may be arranged adjacent or directly contacting the protruding elements when the aerosol-generating article is received in the cavity of the aerosolgenerating device.

[0095] The identification element may be an electrically conductive identification element. The electrical resistance of the identification element may be indicative of a type of aerosolgenerating article.

[0096] The identification element may be a capacitive identification element. The capacitive identification element may be configured to capacitively couple to the capacitive sensing elements of the sensing arrangement when the capacitive identification element is arranged in direct contact or close to or passing by the capacitive sensing elements of the sensing arrangement. This capacitive coupling may be utilized to identify one or more of the presence of the aerosol-generating device or the type of the aerosol-generating device.

[0097] The invention further relates to a method for manufacturing protruding elements of a cavity of the aerosol-generating device, comprising: providing a cavity in an aerosol-generating device configured for receiving an aerosolgenerating article comprising aerosol-forming substrate, providing the cavity with protruding elements that may extend in a radial direction, wherein airflow channels may be formed in between the protruding elements. The protruding elements may comprise at least part of a sensing arrangement. The invention further relates to a method for manufacturing protruding elements of a cavity of the aerosol-generating device, comprising: providing a cavity in an aerosol-generating device configured for receiving an aerosolgenerating article comprising aerosol-forming substrate, providing the cavity with protruding elements extending in a radial direction, wherein airflow channels are formed in between the protruding elements. The protruding elements comprise heating elements.

[0098] The protruding elements may be made by metal stamping, metal bending or metal plating.

[0099] 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 in relation to the direction in which a user draws on the aerosol-generating device during use thereof.

[0100] 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 an opening of the cavity. The cavity may be configured to receive the aerosol-generating article. The aerosol-generating device comprises a distal end opposed to the proximal or mouth end. The proximal or mouth end of the aerosol-generating 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 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.

[0101] 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 aerosol-forming substrate are released to form an inhalable aerosol.

[0102] 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 heating element.

[0103] The electric circuitry may further be electrically connected with the sensing arrangement. The electric circuitry may be configured to detect an aerosol-generating article based on the output of the sensing arrangement. The electric circuitry may be configured to prevent aerosol generation if an aerosol-generating article is not detected. The electric circuitry may be configured to detect a type of inserted aerosol-generating article based on the output of the sensing arrangement. The electric circuitry may be configured to prevent aerosol generation if a certain type, or one of a plurality of certain types, of aerosol-generating article is not detected. The electric circuitry may be configured to apply one of a plurality of heating profiles depending on the type of aerosol-generating article detected. For instance, the electric circuitry may be configured to apply a first heating profile for a first type of aerosol-generating article detect and may be configured to apply a second heating profile for a second type of aerosol-generating article detected.

[0104] If the protruding elements comprise heating elements, the electric circuitry may be configured to control supply of electrical energy from the power supply to the heating elements.

[0105] The aerosol-generating device may comprise a power supply, typically a battery, within a main body of the aerosol-generating device. 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- Iron-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.

[0106] In any of the aspects of the disclosure, the heating element may comprise 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- titanium- zirconium-, 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.

[0107] As described, in any of the aspects of the disclosure, the heating element may be part of the aerosol-generating device. The aerosol-generating device may comprise an internal heating element or an external heating element, or both internal and external heating elements, where "internal" and "external" refer to the aerosol-forming substrate. An internal heating element may take any suitable form. For example, an 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 electro-conductive portions, or an electrically resistive metallic tube. Alternatively, the internal heating element may be one or more heating needles or rods that run through the center of the aerosol-forming substrate. Other alternatives include a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire or a heating plate. Optionally, the internal heating element may be deposited in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal having a 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 ceramic material, and then sandwiched in another insulating material, such as a glass. Heaters formed in this manner may be used to both heat and monitor the temperature of the heating elements during operation. An external heating element may take any suitable form. For example, an 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 can be shaped to conform to the perimeter of the substrate receiving cavity. Alternatively, an external heating element may take the form of a metallic grid or grids, a flexible printed circuit board, a molded interconnect device (MID), ceramic heater, flexible carbon fibre heater or may be formed using a coating technique, such as plasma vapour deposition, on a suitable shaped substrate. An external heating element may also be formed using a metal having a 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 materials. An external heating element formed in this manner may be used to both heat and monitor the temperature of the external heating element during operation.

[0108] As an alternative to an electrically resistive heating element, the heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. In general, a susceptor is a material that is capable of generating heat, when penetrated by an alternating magnetic field. When located in an alternating magnetic field. If the susceptor is conductive, then typically eddy currents are induced by the alternating magnetic field. If the susceptor 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, 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. Commonly all these changes in the susceptor that happen on a nano-scale or below are referred to as “hysteresis losses”, because they produce heat in the susceptor. Hence, if the susceptor is both magnetic and electrically conductive, both hysteresis losses and the generation of eddy currents will contribute to the heating of the susceptor. If the susceptor is magnetic, but not conductive, then hysteresis losses will be the only means by which the susceptor will heat, when penetrated by an alternating magnetic field. According to the invention, the susceptor may be electrically conductive or magnetic or both electrically conductive and magnetic. An alternating magnetic field generated by one or several induction coils heat the susceptor, 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. Such a transfer of heat is best, if the susceptor is in close thermal contact with the aerosol-forming substrate. As described herein, the susceptor may be arranged between the protruding elements and the retaining protrusions. 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.

[0109] 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.

[0110] 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.

[0111] The aerosol-generating substrate preferably comprises homogenised tobacco material, an aerosol-former and water. Providing homogenised tobacco material may improve aerosol generation, the nicotine content and the flavour profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenised tobacco involves grinding tobacco leaf, which more effectively enables the release of nicotine and flavours upon heating.

[0112] 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.

[0113] Example 1 . An aerosol-generating device comprising: a cavity configured to receive aerosol-forming substrate; wherein the cavity comprises protruding elements extending in a radial direction, wherein airflow channels are formed in between the protruding elements, wherein the protruding elements comprise heating elements.

[0114] Example 2. The aerosol-generating device according to example 1 , wherein the aerosol-generating device further comprises an air inlet arranged adjacent a proximal end of the cavity. Example 3. The aerosol-generating device according to example 2, wherein the airflow channels are fluidly connected with the air inlet.

[0115] Example 4. The aerosol-generating device according to example 2 or 3, wherein the heating elements are configured to preheat ambient air being drawn through the air inlet and into the airflow channels adjacent the protruding elements.

[0116] Example 5. The aerosol-generating device according to any of the preceding examples, wherein the heating elements comprise susceptor material.

[0117] Example 6. The aerosol-generating device according to any of the preceding examples, wherein the aerosol-generating device further comprises an induction coil arranged surrounding the heating elements.

[0118] Example 7. The aerosol-generating device according to any of examples 1 to 4, wherein the heating elements are configured as resistive heating elements.

[0119] Example 8. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are configured as ribs.

[0120] Example 9. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are arranged on an inner sidewall of the cavity.

[0121] Example 10. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements extend radially inwards.

[0122] Example 11. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements each comprise a radially inwards facing contacting surface configured for contacting an aerosol generating article received in the cavity.

[0123] Example 12. The aerosol-generating device according to example 11 , wherein the radially inwards facing contacting surfaces are configured to retain the aerosol-generating article in the cavity.

[0124] Example 13. The aerosol-generating device according to example 11 or 12, wherein the radially inwards facing contacting surfaces comprise a coating, preferably a gold coating.

[0125] Example 14. The aerosol-generating device according to any of examples 11 to 13, wherein the protruding elements comprising the radially inwards facing contacting surfaces are configured as electrodes.

[0126] Example 15. The aerosol-generating device according to any of examples 11 to 13, wherein the protruding elements comprising the radially inwards facing contacting surfaces are configured as capacitive sensing elements, preferably having a dielectric constant different from ambient air.

[0127] Example 16. The aerosol-generating device according to any of examples 11 to 15, wherein a distance between radially inwards facing contacting surfaces of the protruding elements decreases in a distal direction. Example 17. The aerosol-generating device according to example 16, wherein the distance decreases from a distance larger than an outer diameter of the aerosol-generating article to a distance corresponding to or smaller than the outer diameter of the aerosolgenerating article to assist holding of the aerosol-generating article in the cavity.

[0128] Example 18. The aerosol-generating device according to example 16 or 17, wherein the distance between opposite radially inwards facing contacting surfaces of the protruding elements is between 5mm and 9mm, preferably between 6mm and 8mm, more preferably between 6.5mm and 7.2mm.

[0129] Example 19. The aerosol-generating device according to any of the preceding examples, wherein a distance between opposite protruding elements is between 0.5mm and 2.0mm, preferably between 0.7mm and 1.6mm, more preferably between 0.9mm and 1.3mm.

[0130] Example 20. The aerosol-generating device according to any of examples 11 to 16, wherein proximal portions of the radially inwards facing contacting surfaces are chamfered or curved to assist insertion of the aerosol-generating article.

[0131] Example 21. The aerosol-generating device according to any of examples 11 to 20, wherein longitudinal side surfaces of the protruding elements have a positive draft angle.

[0132] Example 22. The aerosol-generating device according to example 21 , wherein the positive draft angle is between 0.5° and 10°, preferably between 1° and 5°, more preferably between 1.5° and 2.5°.

[0133] Example 23. The aerosol-generating device according to example 2 or 3, wherein the air inlet is formed between an inner sidewall of the cavity and an aerosol-generating article received in the cavity.

[0134] Example 24. The aerosol-generating device according to example 1 or 4, wherein the protruding elements are arranged on an outer periphery of the cavity.

[0135] Example 25. The aerosol-generating device according to example 24, wherein the protruding elements extend radially outwards.

[0136] Example 26. The aerosol-generating device according to example 24 or 25, wherein an inner sidewall of the cavity is smooth to enable a tight fit between the cavity and a received aerosol-generating article.

[0137] Example 27. The aerosol-generating device according to example 2 or 3 and any of examples 24 to 26, wherein the air inlet is formed between an outer periphery of the cavity and an outer periphery of a housing of the aerosol-generating device.

[0138] Example 28. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are elongate.

[0139] Example 29. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are made from an electrically conductive material. Example 30. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are made from stainless steel, preferably from stainless steel 316L.

[0140] Example 31. The aerosol-generating device according to example 2 or 3, wherein the air inlet is ring-shaped.

[0141] Example 32. The aerosol-generating device according to any of the preceding examples, wherein at least 6, preferably at least 8, preferably at least 10, most preferably at least 12, protruding elements are provided.

[0142] Example 33. The aerosol-generating device according to any of the preceding examples, wherein the number of protruding elements is between 6 and 18, preferably between 8 and 16, more preferably between 10 and 14, most preferably 12.

[0143] Example 34. The aerosol-generating device according to any of the preceding examples, wherein the airflow channels extend to a base of the cavity.

[0144] Example 35. The aerosol-generating device according to any of the preceding examples, wherein the airflow channels comprise a U-shaped turn at the base of the cavity.

[0145] Example 36. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are arranged at a proximal portion of the cavity.

[0146] Example 37. The aerosol-generating device according to any of the preceding examples, wherein the cavity comprises retaining elements.

[0147] Example 38. The aerosol-generating device according to example 37, wherein the retaining elements comprise retaining protrusions configured to retain the aerosol-generating article when the aerosol-generating article is received in the cavity.

[0148] Example 39. The aerosol-generating device according to example 38, wherein the retaining protrusions extend radially inwards from an inner sidewall of the cavity.

[0149] Example 40. The aerosol-generating device according to example 37 or 38, wherein the retaining protrusions are arranged at a distal portion of the cavity.

[0150] Example 41. The aerosol-generating device according to any of the preceding examples, wherein the aerosol-generating device further comprises a heating element configured to heat aerosol-forming substrate received in the cavity.

[0151] Example 42. The aerosol-generating device according to example 41 , wherein the heating element is configured as an inductive heating element.

[0152] Example 43. The aerosol-generating device according to example 41 or 42, wherein the heating element is arranged distal of the protruding elements.

[0153] Example 44. The aerosol-generating device according to any of examples 41 to 43, wherein the heating element is arranged at least partly, preferably fully, surrounding the cavity. Example 45. The aerosol-generating device according to any of examples 41 to 44 and example 40, wherein the heating element is arranged between the protruding elements and the retaining protrusions.

[0154] Example 46. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements comprise at least part of a sensing arrangement.

[0155] Example 47. The aerosol-generating device according to example 46, wherein the sensing arrangement is configured as an article sensor.

[0156] Example 48. The aerosol-generating device according to example 46 or 47, wherein the sensing arrangement is configured to detect a type of aerosol-generating article received in the cavity.

[0157] Example 49. The aerosol-generating device according to any of examples 46 to 48, wherein the sensing arrangement is configured to detect the presence of an aerosolgenerating article in the cavity.

[0158] Example 50. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements have a varying thickness.

[0159] Example 51. The aerosol-generating device according to any of the preceding examples, wherein the airflow channels have a total cross-sectional area of between 0,8 mm2and 4,0 mm2.

[0160] Example 52. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements have a trapezoidal shape.

[0161] Example 53. The aerosol-generating device according to any of the preceding examples, wherein the protruding elements are made by metal stamping, metal bending or metal plating.

[0162] Example 54. An aerosol-generating system comprising the aerosol-generating device according to any of the preceding examples and an aerosol-generating article comprising aerosol-forming substrate.

[0163] Example 55. The aerosol-generating system according to example 54, wherein the aerosol-generating article comprises an identification element.

[0164] Example 56. The aerosol-generating system according to example 55, wherein the identification element is arranged on or adjacent an outer periphery of the aerosol-generating article.

[0165] Example 57. The aerosol-generating system according to example 55 or 56, wherein the identification element is a metal strip.

[0166] Example 58. The aerosol-generating system according to any of examples 55 to 57, wherein the identification element is arranged adjacent or directly contacting the protruding elements when the aerosol-generating article is received in the cavity of the aerosol-generating device.

[0167] Example 59. A method for manufacturing protruding elements of a cavity of the aerosol-generating device, comprising: providing a cavity in an aerosol-generating device configured for receiving an aerosolgenerating article comprising aerosol-forming substrate, providing the cavity with protruding elements extending in a radial direction, wherein airflow channels are formed in between the protruding elements, wherein the protruding elements comprise heating elements.

[0168] Example 60. The method according to example 59, wherein the protruding elements are made by metal stamping, metal bending or metal plating.

[0169] Features described in relation to one embodiment may equally be applied to other embodiments of the invention.

[0170] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0171] Fig. 1 shows a side sectional view of the aerosol-generating device with inserted aerosol-generating article;

[0172] Fig. 2 shows a more detailed view of the elements of a cavity of the aerosol-generating device;

[0173] Fig. 3 shows a detailed view of protruding elements of the cavity;

[0174] Fig. 4 shows a detailed view of an alternative embodiment of the protruding elements;

[0175] Fig. 5 shows an arrangement of the protruding elements in a sidewall of the cavity;

[0176] Fig. 6 shows an individual protruding element;

[0177] Fig. 7 shows a frame having two ribbons utilized during manufacturing of the protruding elements; and

[0178] Fig. 8 shows insertion of the protruding elements into the sidewall of the cavity.

[0179] Figure 1 shows an aerosol-generating device 10, more specifically a proximal part of an aerosol-generating device 10. An aerosol-generating article 12 is inserted into a cavity 14 of the aerosol-generating device 10. Figure 1 further indicates sections of the cavity 14. In a first section 16, protruding elements 18 are arranged. In a second section 20, heating of aerosol-forming substrate 22 of the aerosol-generating article 12 takes place and in a third section 24, retaining protrusions 26 are arranged. The protruding elements 18 as well as the retaining protrusions 26 will be described with respect to the further figures below.

[0180] Figure 1 further shows an airflow into the aerosol-generating device 10, within the cavity 14, into the aerosol-generating article 12 and through the aerosol-generating article 12. In more detail, an air inlet 38 is provided at a proximal end of the cavity 14 and between a sidewall 34 of the cavity 14 and the outer periphery of the aerosol-generating article 12 when the aerosolgenerating article 12 is inserted into the cavity 14. Subsequently, ambient air flows in a distal direction through airflow channels 40 formed between side surfaces 36 of the protruding elements 18. The airflow channels 40 are described in more detail with respect to the below described figures. Adjacent a distal end of the cavity 14, the air makes a U-turn and is drawn into the distal end face of the aerosol-generating article 12. The air then travels through the aerosol-generating article 12. When traveling through the aerosol-forming substrate 22 of the aerosol-generating article 12, vaporized aerosol-forming substrate 22 is entrained in the airflow. The aerosol-forming substrate 22 is vaporized by means of the heating element 28 of the aerosol-generating device 10 heating the aerosol-forming substrate 22 of the aerosolgenerating article 12. Further downstream, aerosol is generated by mixing of ambient air with the air traveling through the aerosol-generating article 12. The mixing of ambient air is facilitated by perforations 42 provided in the outer periphery of the aerosol-generating article 12, more specifically in a ventilation portion 44 of the aerosol-generating article 12. The ventilation portion 44 of the aerosol-generating article 12 is preferably arranged outside of the cavity 14 when the aerosol-generating article 12 is arranged in the cavity 14 such that ambient air can directly be drawn into the ventilation portion 44. Finally, the generated aerosol leaves the aerosol-generating article 12 at a proximal end face and can be inhaled by a user.

[0181] Figure 2 shows a more detailed view of the protruding elements 18 of the cavity 14 of the aerosol-generating device 10. In more detail, the protruding elements 18 are shown in the first section 16 (indicated in figure 1). The protruding elements 18 are provided as an integral part of the cavity 14, more particularly a proximal portion of the cavity 14. The protruding elements 18 are protruding inwards. In other words, the protruding elements 18 are protruding towards a longitudinal central axis of the cavity 14. As a result, the inwards facing contacting surfaces 30 (described in more detail with respect to the further figures) are the most inwards facing parts of the protruding elements 18 and will contact the outer periphery of the aerosolgenerating article 12 when the aerosol-generating article 12 is inserted into the cavity 14. The inwards facing configuration of the protruding elements 18 is shown in more detail in below described Figure 3, while an alternative configuration of the protruding elements 18 in which the protruding elements 18 protruding out what is shown in below described Figure 4.

[0182] Distal of the first section 16, a heating element 28 is shown (which is arranged in the second section 20 shown in Figure 1). The heating element 28 is configured as an induction heater, preferably as a tubular susceptor. To complete the induction heating, the aerosolgenerating device 10 comprises an induction coil surrounding the heating element. The induction coil is not shown. Alternatively, the heating element 28 is configured as a resistive heater, preferably as a heating track printed onto a polyimide substrate.

[0183] In addition, or alternatively, the heating element 28 may comprise a susceptor as part of the aerosol-generating article 12 (e.g., a susceptor strip embedded in the aerosol-forming substrate of the aerosol-generating article). In this example, the aerosol-generating device 10 comprises an induction coil surrounding the aerosol-generating article 12 (once inserted into the cavity 14) for heating the susceptor of the aerosol-generating article.

[0184] The heating element 28 may be arranged surrounding the second section 20 of the cavity 14 or may form the sidewall 34 of the cavity 14 in the area of the second section 20.

[0185] In a distal portion of the cavity 14, the retaining protrusions 26 are arranged. The retaining protrusions 26 are configured as inwards facing protrusions so as to contact the outer periphery of the aerosol-generating article 12 when the aerosol-generating article 12 is inserted into the cavity 14. The aerosol-generating article 12 is thus securely held in the cavity 14 by means of a gripping action of the protruding elements 18 in the proximal portion of the cavity 14 and by means of the retaining protrusions 26 at the distal portion of the cavity 14.

[0186] Figure 3 shows the inwards facing configuration of the protruding elements 18 in more detail. Also, in the embodiment shown in figure 3, the protruding elements 18 are integrally formed with the cavity 14, or, more precisely, a sidewall 34 of the cavity 14. However, it should be appreciated that the protruding elements 18 may alternatively be provided as separate elements and attached to the inner sidewall 34 of the cavity 14.

[0187] Figure 3 further shows a preferred embodiment of the protruding elements 18 in which the most proximal portion of each respective protruding element 18 is configured with a chamfer 32. The chamfer 32 helps insertion of the aerosol-generating article 12 by guiding the aerosol-generating article 12 into a central position within the cavity 14.

[0188] Figure 3 further shows a positive draft angle of the protruding elements 18. In more detail, side surfaces 36 of the protruding elements 18 are provided with a positive draft angle. Between individual protruding elements 18, the airflow channels 40 are formed. The airflow channels 40 are thus formed between the inner sidewall 34 of the cavity 14, side surfaces 36 of adjacent protruding elements 18 and the outer periphery of the aerosolgenerating article 12 when the aerosol-generating article 12 is received in the cavity 14.

[0189] Figure 4 shows an alternative configuration of the protruding elements 18. In more detail, the protruding elements 18 in this configuration are arranged as a radially outward facing protruding elements 18. The protruding elements 18 in this configuration are arranged on the outer periphery of the cavity 14 and the protrusion extend in a radially outwards direction. The inner sidewall 34 of the cavity 14 is smooth such as to enable a snug fit of the aerosolgenerating article 12 within the cavity 14.

[0190] As a consequence, the airflow channels 40 are arranged on the outside of the cavity 14. The airflow channels 40 are formed between the outer periphery of the cavity 14, side surfaces 36 of adjacent protruding elements 18 and an outermost part. The outermost part may be the housing of the aerosol-generating device 10 or an internal part of the aerosolgenerating device 10. The internal part may be a dedicated wall to form the airflow channels 40 or a different element such as, for example, a thermal insulation wall.

[0191] Figure 5 shows a configuration of inwards facing protruding elements 18. In contrast to Figure 3, the protruding elements 18 are not integrally formed with the cavity 14. Rather, the protruding elements 18 are separate elements which are inserted into slots 46 arranged in the sidewall 34 of the cavity 14 such that only inwards facing parts of the protruding elements 18 actually protrude into the cavity 14. The slots 46 securely hold the protruding elements 18 in place.

[0192] Figure 6 shows a more detailed view of a single protruding element 18 as employed in the Figure 5 embodiment. The part of the protruding elements 18 that actually protrudes into the cavity 14 has a triangular shape. Hence, the proximal portion of this part of the protruding element 18 has a chamfer 32 to enable insertion of the aerosol-generating article 12 into the cavity 14. Additionally, the tip of the triangular shape is configured as a contacting surface 30 in order to contact the outer periphery of the aerosol-generating article 12 when the aerosolgenerating article 12 is inserted into the cavity 14. The contacting surface 30 is preferably part of a sensing arrangement. The contacting surface 30 may alternatively be configured as a heating element.

[0193] In case the contacting surface 30 is part of a sensing arrangement, the contacting surface 30 may be configured as an electrode. This may particularly be beneficial if the aerosolgenerating article 12 is provided with an identification element. The sensing arrangement may be configured to measure the electrical resistance of the identification element of the aerosolgenerating article 12 when the aerosol-generating article 12 is received in the cavity 14. In more detail, the identification element may be arranged on the outer periphery of the aerosolgenerating article 12 such that one or more electrodes of the protruding elements 18 contact this identification element. Then, electrical contact may be established between adjacent electrodes of the protruding elements 18 via the identification element of the aerosolgenerating article 12. Applying a voltage between adjacent electrodes of protruding elements 18 may thus enable measuring the electrical resistance of the identification element.

[0194] As an alternative to configuring the contacting surfaces 30 as or with electrodes, the contacting surfaces 30 could be provided with capacitive sensing elements. This is beneficial if the identification element of the aerosol-generating article 12 is a corresponding capacitive identification element. When the aerosol-generating article 12 is received in the cavity 14, the capacitive identification element may be arranged adjacent or moved past the capacitive contacting surfaces 30 of the protruding elements 18. The sensing arrangement may in this case detect a capacitive coupling between the capacitive contacting surface 30 of the protruding elements 18 and the capacitive identification element of the aerosol-generating article 12.

[0195] Independent whether the sensing arrangement and the corresponding contacting surfaces 30 of the protruding elements 18 are configured as electrodes or as capacitive sensors, the sensing arrangement may be configured to detect the presence of an aerosolgenerating article 12, the type of received aerosol-generating article 12, or both.

[0196] As described herein, the protruding elements 18 may thus have a double functionality. A first functionality of the protruding elements 18 may be to securely hold the aerosolgenerating article 12 within the cavity 14. A second functionality of the protruding elements 18 may be a sensing functionality. Alternatively or additionally, the second functionality of the protruding elements 18 may be a heating functionality.

[0197] In addition or alternatively to the herein described functions of the protruding elements 18, the contact surfaces of the protruding elements 18 may be configured as or may comprise heating elements. As a further addition or as a further alternative, the side surfaces 36 of the protruding elements 18 may be provided with heating elements. Providing heating elements at the contacting surfaces 30 or at the side surfaces 36 of the protruding elements 18 may enable preheating of the ambient air drawn through the airflow channels 40 adjacent the side surfaces 36 of the protruding elements 18. This may be a particularly beneficial effect if only the side surfaces 36 of the protruding elements 18 are provided with heating elements. Providing the contacting surfaces 30 of the protruding elements 18 with heating elements may be beneficial if a heating of the aerosol-generating article 12, more preferably of the aerosol-forming substrate 22 of the aerosol-generating article 12, is preferred. An arrangement of heating elements at the protruding elements 18 may be utilized to heat one or both of the aerosolgenerating article 12, particularly the aerosol-forming substrate 22 of the aerosol-generating article 12, and the ambient air drawn through the airflow channels 40 adjacent side surfaces 36 of the protruding elements 18.

[0198] Figure 7 shows a manufacturing of the protruding elements 18. The manufacturing may comprise metal stamping of the protruding elements 18 with a frame having two ribbons 48 on the side, each of them comprising holes 50; during the assembly step, the whole frame is moving linearly on equipment dedicated to the assembly; thanks to the presence of the holes 50, the positions of the parts (mainly of the protruding elements 18) is better controlled; furthermore, the holes 50 are configured such to be synchronized with the speed of the equipment, once the protruding elements 18 are in position, a vertical cutter (not shown) is operating to detach the protruding elements 18 from the frame; finally, a high-speed mechanical “finger” pushes the protruding elements 18 within a cavity 14 of a tubular component that can subsequently act as the cavity 14 of the aerosol-generating device 10. The individual protruding elements 18 may then be shaped as shown in Figure 6. The individual finalized protruding elements 18 arranged in the cavity 14 may be arranged as shown in Figure 5.

[0199] Figure 8 shows the introduction of the protruding elements 18 into the slots 46 of the sidewall 34 of the cavity 14. After insertion of the protruding elements 18 into the slots 46, the final arrangement of the protruding elements 18 may be as shown in Figure 5.

Claims

CLAIMS1. An aerosol-generating device comprising: a cavity configured to receive aerosol-forming substrate; wherein the cavity comprises protruding elements extending in a radial direction, wherein airflow channels are formed in between the protruding elements, wherein the protruding elements comprise heating elements.

2. The aerosol-generating device according to claim 1 , wherein the aerosolgenerating device further comprises an air inlet arranged adjacent a proximal end of the cavity.

3. The aerosol-generating device according to claim 2, wherein the airflow channels are fluidly connected with the air inlet.

4. The aerosol-generating device according to claim 2 or 3, wherein the heating elements are configured to preheat ambient air being drawn through the air inlet and into the airflow channels adjacent the protruding elements.

5. The aerosol-generating device according to any of the preceding claims, wherein the heating elements are electrically resistive heating elements.

6. The aerosol-generating device according to any of the preceding claims, wherein the protruding elements are configured as ribs.

7. The aerosol-generating device according to any of the preceding claims, wherein the protruding elements are arranged on an inner sidewall of the cavity.

8. The aerosol-generating device according to any of the preceding claims, wherein the protruding elements extend radially inwards.

9. The aerosol-generating device according to any of the preceding claims, wherein the protruding elements each comprise a radially inwards facing contacting surface configured for contacting an aerosol generating article received in the cavity.

10. The aerosol-generating device according to claim 9, wherein the radially inwards facing contacting surfaces are configured to retain the aerosol-generating article in the cavity.

11. The aerosol-generating device according to any of the preceding claims, wherein the cavity comprises retaining elements.

12. The aerosol-generating device according to claim 11 , wherein the retaining elements comprise retaining protrusions configured to retain the aerosol-generating article when the aerosol-generating article is received in the cavity.

13. The aerosol-generating device according to any of the preceding claims, wherein the aerosol-generating device further comprises a heating element configured to heat aerosol-forming substrate received in the cavity.

14. The aerosol-generating device according to claim 13 and claim 11 or 12, wherein the heating element is arranged between the protruding elements and the retaining protrusions.

15. The aerosol-generating device according to claim 13 or 14, wherein the heating element comprises an induction coil.

16. An aerosol-generating system comprising the aerosol-generating device according to any of the preceding claims and an aerosol-generating article comprising aerosolforming substrate.

17. A method for manufacturing protruding elements of a cavity of the aerosolgenerating device, comprising: providing a cavity in an aerosol-generating device configured for receiving an aerosolgenerating article comprising aerosol-forming substrate, providing the cavity with protruding elements extending in a radial direction, wherein airflow channels are formed in between the protruding elements, wherein the protruding elements comprise heating elements.

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