Aerosol generating device for use with an aerosol generating article

Abstract

The present invention relates to an aerosol generating device for use with an aerosol generating article. The device includes a receiving chamber for removably receiving at least a portion of the aerosol generating article. The receiving chamber has an inner surface and a central axis. Along the central axis, the inner surface includes a first axial portion, a second axial portion, and an intermediate axial portion. The intermediate axial portion is positioned between the first axial portion and the second axial portion. The first axial portion includes a plurality of first protrusions. The second axial portion includes a plurality of second protrusions. The plurality of first protrusions and the plurality of second protrusions are configured to contact at least a portion of the aerosol generating article for retaining the aerosol generating article in the receiving chamber. The plurality of first protrusions and the plurality of second protrusions extend beyond the intermediate axial portion of the inner surface in a direction toward the central axis.

Description

Technical Field

[0001] The present invention relates to an aerosol generating device configured for use with an aerosol-generating article to generate an aerosol by heating an aerosol-forming substrate contained in the article. The present invention also relates to an aerosol generating system comprising such a device and such an article. Background Art

[0002] Aerosol generating devices that generate an inhalable aerosol by heating an aerosol-forming substrate are generally known from the prior art. Such devices may include a heater, in particular a resistive heater or an induction heater, for heating the aerosol-forming substrate within the device. The substrate itself may be an integral part of an aerosol-generating article, which may be at least partially received in a receiving chamber of the device. The receiving chamber, in particular the chamber wall, may provide a tight fit for the aerosol-generating article to keep the article in the receiving chamber during use of the device. However, a tight fit may cause undesirable heat losses due to direct heat conduction from the aerosol-generating article to the inner surface of the receiving chamber. In addition, when the article is tightly fitted in the receiving chamber, condensate formation in the receiving chamber may cause undesirable wetting of the article, in particular the substrate contained therein. Such condensate formation may occur when the vaporized compounds of the aerosol-forming substrate are cooled by contact with those parts of the chamber wall that are below the dew point temperature. In addition, a tight fit may restrict the airflow through the receiving chamber, which in turn may cause a high resistance to draw (RID). However, a tight fit is necessary to some extent, as otherwise the article may shift or fall out of the device.This is particularly true when the aerosol-forming substrate tends to shrink during use, which may result in reduced retention of the article by the surrounding chamber.

[0003] It would therefore be desirable to have an aerosol generating device and an aerosol generating system having the advantages of prior art solutions without their limitations. In particular, it would be desirable to have an aerosol generating device and a corresponding system providing improved retention of an aerosol-generating article in a receiving chamber of the device.

[0004] In general, the first axial portion and the second axial portion can be considered as a surface including peaks and valleys, wherein the peaks correspond to the areas of the first protrusions and the second protrusions having the shortest distance to the central axis or being closest to the central axis, and wherein the valleys correspond to the areas between adjacent protrusions having the largest distance to the central axis or being farthest from the central axis. The first protrusion and the second protrusion are part of the first axial portion and the second axial portion, and therefore are part of the inner surface of the receiving chamber. Summary of the invention

[0005] According to the present invention, an aerosol generating device for use with an aerosol generating article is provided. The device comprises a receiving chamber for removably receiving at least a portion of the aerosol generating article. The receiving chamber has an inner surface and a central axis. Along the central axis, the inner surface comprises a first axial portion, a second axial portion and an intermediate axial portion. The intermediate axial portion is positioned between the first axial portion and the second axial portion. The first axial portion comprises a plurality of first protrusions. The second axial portion comprises a plurality of second protrusions. The plurality of first protrusions and the plurality of second protrusions are configured to contact at least a portion of the aerosol generating article, preferably a first support element and a second support element of the aerosol generating article, respectively, for holding the article in the receiving chamber. That is, the plurality of first protrusions are preferably configured to contact the first support element of the aerosol generating article, and the plurality of second protrusions are preferably configured to contact the second support element of the aerosol generating article. The plurality of first protrusions and the plurality of second protrusions extend beyond the intermediate axial portion of the inner surface in a direction toward the central axis. Preferably, the intermediate axial portion is configured to surround a substrate element of the aerosol-generating article when the article is received in the receiving chamber.Preferably, the substrate element of the aerosol-generating article is positioned between the first support element and the second support element of the aerosol-generating article.

[0006] As used herein, the term "extending in a direction toward the central axis" means that the plurality of first protrusions and the plurality of second protrusions extend into the interior of the receiving chamber. Depending on the general shape of the receiving chamber, the direction toward the central axis may be particularly perpendicular to the central axis. In addition, "extending beyond the middle axial portion of the inner surface in the direction toward the central axis" specifically means that in the direction toward the central axis, each of the plurality of first protrusions and the plurality of second protrusions extends beyond a corresponding area of ​​the middle portion having the same azimuthal position relative to the central axis of the receiving chamber. That is, at a given azimuthal position of the corresponding first protrusion or the second protrusion, the middle portion is outwardly recessed relative to the corresponding first protrusion or the second protrusion as seen in an outward direction extending away from the central axis.

[0007] As used herein, the term "configured to contact at least a portion of the aerosol-generating article" should be understood such that each of the plurality of first protrusions and the plurality of second protrusions contacts the aerosol-generating article when the aerosol-generating article is received in the chamber.

[0008] Since the plurality of first protrusions and the plurality of second protrusions extend beyond the intermediate axial portion in a direction towards the central axis, the aerosol-generating article is not in physical contact with the intermediate axial portion when it is received in the chamber. Thus, any direct heat conduction from the aerosol-generating article to the intermediate portion is suppressed. Advantageously, this results in reduced undesired heat losses and thus improved heating efficiency. Furthermore, since there is no direct physical contact between the intermediate axial portion and those portions of the article that directly face the intermediate axial portion when the article is received in the receiving chamber, wetting of the article due to condensation is avoided at least in these portions.

[0009] Furthermore, it will be appreciated that the aerosol generating article is in contact only with the respective first and second protrusions of the first and second axial portions. Thus, the contact surface between the article and the receiving chamber is reduced compared to a receiving chamber without protrusions. Thus, conductive heat exchange between the aerosol generating article and the surrounding receiving chamber as well as wetting of the article are further reduced. Preferably, the plurality of first protrusions and the plurality of second protrusions comprise contact surfaces for contacting the aerosol generating article. The shape of the contact surface is adapted to the shape of the respective portion of the aerosol generating article, with which the respective contact surface contacts the respective portion of the aerosol generating article when the article is inserted into the receiving chamber. In particular, the contact surface may be curved.

[0010] Despite not being in physical contact with the intermediate axial portion, the aerosol-generating article is securely held in the receiving chamber by the first and second protrusions of the first and second axial portions, respectively. In particular, due to the localized nature of the contact between the aerosol-generating article and the first and second protrusions, the holding pressure between the article and the protrusions is locally enhanced, so that the protrusions may form enlarged local depressions in the aerosol-generating article. Advantageously, the local depressions allow compensating for possible shrinkage of the article during use. Thus, the risk of the article shifting or falling out of the aerosol-generating device is advantageously reduced.

[0011] The plurality of first protrusions and the plurality of second protrusions are spaced apart from each other such that air flow channels are formed between adjacent first protrusions and adjacent second protrusions, respectively.

[0012] Advantageously, the number, shape and distance of the plurality of first protrusions and the plurality of second protrusions, respectively, may be selected such that when the aerosol-generating article is inserted into the receiving chamber of the device, the resistance to draw (RTD) is within a desired range. The resistance to draw may be in the range of 70 mmWG to 120 mmWG. Preferably, the resistance to draw (RTD) may be between 40 mmWG and 70 mmWG, in particular between 45 mmWG and 65 mmWG, for example 55 mmWG.

[0013] The plurality of first protrusions and the plurality of second protrusions may include at least two first protrusions and the second protrusions, respectively. In particular, the plurality of first protrusions and the plurality of second protrusions may include two, three, four or more first protrusions and the second protrusions, respectively. Preferably, the plurality of first protrusions include twelve first protrusions. Similarly, the plurality of second protrusions include twelve second protrusions. Such numbers provide a reasonable balance between sufficiently large retention of the article and sufficient reduction of the above-mentioned adverse effects.

[0014] The plurality of first protrusions or the plurality of second protrusions or both the plurality of first protrusions and the plurality of second protrusions may be arranged in a regular pattern along the inner circumference of the receiving chamber. The plurality of first protrusions and the plurality of second protrusions may be evenly distributed along the inner circumference of the receiving chamber, respectively. In particular, the plurality of first protrusions and the plurality of second protrusions may be evenly spaced from each other by respective valleys (gaps) arranged between two adjacent protrusions, respectively. Advantageously, this enables uniform and therefore particularly safe retention of the aerosol-generating article.

[0015] The receiving chamber may have a generally cylindrical shape. As used herein, the term "generally cylindrical shape" refers to the shape of the receiving chamber when the protrusions are masked or any protrusions are not taken into account, that is, to the shape of the envelope of the radially outermost portion of the inner surface of the receiving chamber. In the case of a generally cylindrical receiving chamber, a plurality of first protrusions and a plurality of second protrusions extend beyond the intermediate axial portion in a radially inward direction toward the central axis. In particular, any distance between the inner surface and the central axis is measured in a radial direction relative to the central axis, that is, in a direction perpendicular to the central axis. Preferably, the envelope surface that intersects the peak of each of the plurality of first protrusions preferably also has a generally cylindrical shape. Similarly, the envelope surface that intersects the peak of each of the plurality of second protrusions preferably also has a generally cylindrical shape.

[0016] Alternatively, the receiving chamber may have a generally conical, in particular generally conical or generally frustoconical shape. As used herein, the term "generally conical, in particular generally conical or generally frustoconical shape" refers to the shape of the receiving chamber when the protrusions are masked or when any protrusions are not taken into account, that is, to the shape of the envelope of the radially outermost part of the inner surface of the receiving chamber. For any of these shapes, any distance between the inner surface and the central axis is preferably measured perpendicular to the generally conical surface, in particular generally conical or generally frustoconical shape. Preferably, the envelope surface that intersects the peak of each of the plurality of first protrusions also has a generally conical, in particular generally conical or generally frustoconical shape. Similarly, the envelope surface that intersects the peak of each of the plurality of second protrusions may also have a generally conical, in particular generally conical or generally frustoconical shape.

[0017] Preferably, the middle portion does not contain any protrusions or does not have any protrusions. That is, the middle portion preferably does not include any protrusions. In particular, the plurality of first protrusions and the plurality of second protrusions may be the only protrusions of any axial portion of the inner surface. Likewise, the middle portion preferably does not contain any indentations or does not have any indentations. That is, the middle portion preferably does not include any indentations. In particular, the middle portion of the inner surface may be uniform. As used herein, the term "uniform" refers to a smooth surface that may be flat or planar as well as curved. Therefore, the middle axial portion may be smooth, and in particular may not have protrusions and indentations.

[0018] Alternatively, the middle portion may include one or more third protrusions. For example, the middle portion may be corrugated. However, each of the one or more third protrusions of the middle portion is outwardly recessed relative to the envelope surface that intersects the peaks of each of the plurality of first protrusions and the plurality of second protrusions. That is, each of the one or more third protrusions preferably does not extend inwardly toward the central axis beyond the envelope surface that intersects the peaks of each of the plurality of first protrusions and the plurality of second protrusions.

[0019] The receiving chamber may comprise an insertion opening through which the aerosol generating article may be inserted into the receiving chamber. As used herein, the direction in which the aerosol generating article is inserted is denoted as the insertion direction. Preferably, the insertion direction corresponds to an extension of the central axis of the receiving chamber. When inserted into the receiving chamber, at least a portion of the aerosol generating article may still extend outwards through the insertion opening. The outwardly extending portion is preferably provided for interaction with a user, in particular for being placed in the user's mouth. Thus, during use of the device, the insertion opening may be close to the user's mouth. As used herein, when the device is in use, a section close to the insertion opening or close to the user's mouth, respectively, is denoted with the prefix "proximal". A section arranged further away is denoted with the prefix "distal".

[0020] Hence, the receiving chamber may be arranged or positioned in a proximal portion of the aerosol generating device. Likewise, the insertion opening may be arranged or positioned at a proximal end of the aerosol generating device.

[0021] Preferably, the first axial portion is at least partially positioned in the distal end portion of the receiving chamber. Likewise, the second axial portion is preferably at least partially positioned in the proximal end portion of the receiving chamber.

[0022] The aerosol generating device may include a cover for covering the insertion opening of the receiving chamber. The cover may be releasably attached to the body of the aerosol generating device. In particular, the cover may be hinged, that is, the cover may be attached to the body of the aerosol generating device by a hinge. Similarly, the receiving chamber of the aerosol generating device may be hinged, which may be opened by a hinge. For example, the aerosol generating device may include two housing parts, each of which forms at least a part of the receiving chamber, which is connected to each other by a hinge. In any of these configurations, the receiving chamber can be laterally approached relative to the central axis. That is, the aerosol generating article can be inserted into the receiving chamber laterally relative to the central axis. In addition to the lateral accessibility, the receiving chamber may also include an opening, through which at least a part of the aerosol generating article can extend outward when inserted into the receiving chamber, particularly in a direction corresponding to the direction of the central axis of the receiving chamber.

[0023] In general, the lengths of the first axial portion, the second axial portion and the intermediate axial portion may depend on the design of the aerosol-forming article to be received and held in the receiving chamber. As will be described in more detail below, the article may comprise different elements. In particular, in case the aerosol-generating article has a substantially rod-shape, the article may comprise different elements arranged sequentially along the length axis of the article. Preferably, each portion of the inner surface of the receiving chamber, that is to say the first axial portion, the second axial portion and the intermediate axial portion, is assigned to a specific element of the aerosol-forming article.

[0024] The first axial portion and the second axial portion may have equal lengths in the direction of the central axis. Advantageously, the equal lengths of the first axial portion and the second axial portion provide uniform retention of the product in the receiving chamber. Alternatively, the first axial portion and the second axial portion may have different lengths in the direction of the central axis.

[0025] The intermediate axial portion may have a length in the direction of the central axis of at least 20% of the length of the inner surface or the receiving chamber. Preferably, the intermediate portion has a length in the range of 20% to 40%, in particular 25% to 40%, in particular 30% to 35% of the length of the inner surface or the receiving chamber. Advantageously, such a length provides a sufficient reduction of the above-mentioned adverse effects.

[0026] The first axial portion, the second axial portion and the intermediate axial portion together may have a length of at least 50%, in particular 75%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, most preferably continuously 100% of the total length of the receiving chamber or the inner surface in the direction of the central axis. That is, the first axial portion, the second axial portion and the intermediate axial portion together may cover at least 50%, in particular 75%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, most preferably continuously 100% of the total length of the receiving chamber or the inner surface in the direction of the central axis.

[0027] One or more, in particular all of the plurality of first protrusions may extend in a direction substantially along the central axis of the receiving chamber. Likewise, one or more, in particular all of the plurality of second protrusions may extend in a direction substantially along the central axis of the receiving chamber. The extension direction substantially along the central axis may be parallel to the central axis, in particular in the case of a substantially cylindrical receiving chamber. Thus, one or more, in particular all of the plurality of first protrusions may extend parallel to the central axis. Likewise, one or more, in particular all of the plurality of second protrusions may extend parallel to the central axis. Likewise, the extension direction of the corresponding protrusion substantially along the central axis may be inclined relative to the central axis (e.g., inclined by 2 to 5 degrees), but still located in a common plane corresponding to the central axis. The latter case is particularly applicable to substantially conical, such as conical or frustoconical receiving chambers. Thus, in general, one or more, in particular all of the plurality of first protrusions may extend along a corresponding plane containing the central axis. Likewise, one or more, in particular all of the plurality of second protrusions may extend along a corresponding plane containing the central axis.

[0028] Advantageously, the extension direction of the respective protrusion substantially along the central axis facilitates the insertion and removal of the aerosol-generating article into and from the receiving chamber. This applies in particular when the insertion direction corresponds to the direction of the central axis.

[0029] As seen in the direction of the central axis, the plurality of first protrusions and the plurality of second protrusions may be arranged so that the position of each first protrusion coincides with the position of the corresponding second protrusion. In particular, the plurality of first protrusions and the plurality of second protrusions may be arranged so that each first protrusion superimposes the corresponding second protrusion as seen in the direction of the central axis.

[0030] The aerosol generating device may comprise one or more end stops arranged in the receiving chamber, in particular at the distal end of the receiving chamber. The one or more end stops are preferably configured to limit the insertion depth of the aerosol generating article into the receiving chamber. In particular, the one or more end stops may be configured to prevent the aerosol generating article from abutting the inner surface of the receiving chamber at the distal end of the receiving chamber, the distal end of the receiving chamber being opposite to the insertion opening of the receiving chamber at the proximal end of the receiving chamber. Therefore, the one or more end stops advantageously provide a free space in the distal part of the receiving chamber, allowing a free airflow between the distal end of the receiving chamber and the distal end of the aerosol generating article when the article is received in the receiving chamber. The one or more end stops may comprise a contact surface, against which the aerosol generating article, in particular the distal end of the aerosol generating article, may abut when the article is received in the receiving chamber.

[0031] Preferably, the aerosol generating device may comprise a plurality of separate end stops, for example three end stops, which are arranged within the receiving chamber, in particular at a distal end of the receiving chamber.

[0032] A plurality of end stops may be symmetrically arranged around the central axis. In particular, a plurality of end stops may be equally spaced around the central axis. As described above, this allows free airflow around the end stops and the products received in the receiving chamber.

[0033] The end stop or stops preferably have a dimension in the direction of the centre axis in the range of 0.5 to 5 mm, in particular in the range of 1 to 4 mm, preferably in the range of 1 to 2 mm, for example 1.4 mm.

[0034] The one or more end stops preferably have a shape and size such as extending beyond the plurality of first protrusions and the plurality of second protrusions in a direction towards the central axis. The one or more end stops preferably have a radial extension perpendicular to the central axis in the range of 0.7 mm to 6 mm, in particular in the range of 1 mm to 5 mm, preferably in the range of 2 mm to 4 mm.

[0035] Preferably, one or more end stops may have the shape of an annular segment, in particular in the case where the receiving chamber has a substantially cylindrical shape. The annular segment may have a height dimension in the direction of the central axis and a radial dimension perpendicular to the central axis. As mentioned above, the height dimension of the annular segment may be in the range of 0.5 mm to 5 mm, in particular in the range of 1 mm to 4 mm, preferably in the range of 1 mm to 2 mm. The radial dimension of the annular segment may be in the range of 0.7 mm to 6 mm, in particular in the range of 1 mm to 5 mm, preferably in the range of 1 mm to 3 mm, for example 1.3 mm.

[0036] For example, the receiving chamber may be formed as an elongated cavity including a bottom at the distal end of the receiving chamber. In this configuration, one or more end stops may be arranged in the receiving chamber so as to protrude from the bottom at the distal end in a direction toward the proximal end of the receiving chamber, in particular in a direction opposite to the insertion direction of the article.

[0037] The aerosol generating device may provide a specific resistance to draw when the aerosol generating article is inserted into the receiving chamber. In general, the resistance to draw is determined by, among other things, the specific shape and size of the receiving chamber, the number, shape and size of the first and second protrusions, and, if present, the number, shape and size of the one or more end stops. Thus, the resistance to draw may be specifically adjusted by a proper selection of the number, shape and size of the first protrusions or the number, shape and size of the second protrusions, or, if present, the number, shape and size of the one or more end stops.

[0038] Preferably, the airflow channel defined between the plurality of first protrusions, the plurality of second protrusions and (if present) one or more end stops has a size such that when the device is in use, the resistance to draw (RTD) is between 70 mmWG and 120 mmWG. Preferably, the resistance to draw (RTD) may be between 40 mmWG and 70 mmWG, in particular between 45 mmWG and 65 mmWG, for example 55 mmWG. As used herein, the resistance to draw relates to an aerosol generating device in use, that is to say to a system comprising an aerosol generating device and an aerosol generating article received in a receiving chamber of the device.

[0039] If present, the one or more end stops may reduce the airflow channel defined between the plurality of first protrusions and the plurality of second protrusions, in particular in the case where the end stop partially or even completely covers or blocks the airflow channel defined between adjacent protrusions. Thus, the one or more end stops may increase the resistance to suction compared to a device without any end stop. Preferably, the resistance to suction is increased by at most 50%, in particular by at most 25%, in particular by at most 15%, compared to a device without any end stop.

[0040] Preferably, at least one of the number, shape and size of one or more end stops is selected so that when the device is in use, the suction resistance is at most 150%, in particular at most 140%, preferably at most 130%, even more preferably at most 120% of the suction resistance in the absence of one or more end stops or without considering one or more end stops.

[0041] Therefore, at least one of the number, shape and size of one or more end stops can be selected so that in use of the device, the air flow passing between the multiple first protrusions, the multiple second protrusions and the one or more end stops is at least 50%, in particular at least 60%, preferably at least 70%, and even more preferably at least 80% of the air flow passing between the multiple first protrusions and the multiple second protrusions in the absence of one or more end stops.

[0042] Likewise, the one or more end stops may cover at most 50%, in particular at most 40%, preferably at most 30%, even more preferably at most 20% of the total cross-sectional area of ​​all gaps (free spaces) defined between adjacent first protrusions or between adjacent second protrusions as seen in a plane perpendicular to the central axis. To this end, at least one of the number, shape and size of the one or more end stops may be selected so as to cover at most 50%, in particular at most 40%, preferably at most 30%, even more preferably at most 20% of the total cross-sectional area of ​​all gaps (free spaces) defined between adjacent first protrusions or between adjacent second protrusions as seen in a plane perpendicular to the central axis.

[0043] In the absence of any end stop or without taking into account the possible reduction in cross-sectional area due to the presence of one or more end stops, the total cross-sectional area of ​​all gaps (free spaces) defined between adjacent first protrusions or adjacent second protrusions as seen in a plane perpendicular to the central axis can be in the range of 2 square millimeters to 9 square millimeters, in particular in the range of 3 square millimeters to 8 square millimeters, preferably in the range of 3 square millimeters to 6 square millimeters.

[0044] In contrast, when taking into account the reduction in the free total cross-sectional area of ​​all voids, the (reduced free) total cross-sectional area of ​​all voids defined between adjacent first protrusions or between adjacent second protrusions as seen in a plane perpendicular to the central axis may be in the range of 2 mm2 to 7 mm2, in particular in the range of 3 mm2 to 7 mm2, preferably in the range of 4 mm2 to 6 mm2. The minimum free cross-sectional area as described above ensures minimum airflow and therefore minimum suction resistance during use of the device.

[0045] Preferably, the receiving chamber has a substantially circular cross-section as seen in a plane perpendicular to the central axis. In particular, the intermediate axial portion may have a circular cross-section as seen in a plane perpendicular to the central axis. Likewise, at least one of the first axial portion and the second axial portion may have a substantially circular cross-section as seen in a plane perpendicular to the central axis, without taking into account the first protrusion or the second protrusion, respectively.

[0046] Alternatively, the receiving chamber may also have a substantially elliptical cross section, or a substantially oval cross section, or a substantially square cross section, or a substantially rectangular cross section, or a substantially triangular cross section, or a substantially polygonal cross section. As used herein, the above cross-sectional shape preferably refers to the cross-sectional shape of the receiving chamber without considering any protrusions.

[0047] Similarly, the envelope curve around the central axis that intersects the peak of each of the plurality of first protrusions or the plurality of second protrusions, respectively, may have one of a generally circular or generally elliptical shape, or a generally oval shape, or a generally rectangular shape, or a generally triangular shape, or a generally polygonal shape. Preferably, the shape of the envelope curve around the central axis that intersects the peak of each of the plurality of first protrusions or the plurality of second protrusions, respectively, corresponds to the cross-sectional shape of the aerosol-generating article to be received in the receiving chamber.

[0048] The area of ​​the first axial portion, in particular the area between adjacent first protrusions and the area of ​​the middle portion can be arranged on a common shell surface, in particular on a common cylindrical shell surface. Similarly, the area of ​​the second axial portion, in particular the area between adjacent second protrusions and the area of ​​the middle portion can be arranged on a common shell surface, in particular on a common cylindrical shell surface. Similarly, the area of ​​the first axial portion, in particular the area between adjacent first protrusions and the area of ​​the second axial portion, in particular the area between adjacent second protrusions can be arranged on a common shell surface, in particular on a common cylindrical shell surface. Preferably, the area of ​​the first axial portion, in particular the area between adjacent first protrusions and the area of ​​the second axial portion, in particular the area between adjacent second protrusions, and the area of ​​the middle portion can be arranged on a common shell surface, in particular on a common cylindrical shell surface.

[0049] Alternatively, the region of the middle portion may be arranged to be recessed outwardly relative to the region between the adjacent first protrusions or the region between the adjacent second protrusions, or relative to both the region between the adjacent first protrusions and the region between the adjacent second protrusions.

[0050] At least one of the plurality of first protrusions, preferably all of the protrusions, may have a constant height extension along the extension of the corresponding protrusion perpendicular to the central axis. Similarly, at least one of the plurality of second protrusions, preferably all of the protrusions, may have a constant height extension along the extension of the corresponding protrusion perpendicular to the central axis. The height extension is defined as the distance between the area of ​​the corresponding protrusion having the shortest distance to the central axis and the area of ​​the corresponding protrusion having the largest distance to the central axis. In particular, the height extension may be defined as the distance between the peak of the corresponding protrusion and the adjacent valley as seen in a direction toward the central axis, preferably perpendicular to the central axis. Advantageously, this provides uniform retention of the article in the device.

[0051] The height of at least one of the plurality of first protrusions and the plurality of second protrusions may be in the range of 0.2 mm to 1.5 mm, in particular 0.3 mm to 1 mm, preferably 0.4 mm to 0.8 mm, more preferably 0.4 mm to 0.6 mm, for example 0.5 mm.

[0052] In particular, with respect to the cylindrically shaped receiving chamber, at least one of the plurality of first protrusions, preferably all protrusions, may have a constant radial distance from the central axis along the extension of the respective protrusion perpendicular to the central axis. Likewise, at least one of the plurality of second protrusions, preferably all protrusions, may have a constant radial distance from the central axis along the extension of the respective protrusion perpendicular to the central axis. The radial distance extension is defined as the distance between the central axis and the area of ​​the respective protrusion having the shortest distance to the central axis.

[0053] The receiving chamber may be a multi-part component. In particular, the receiving chamber may comprise a first part and a second part, wherein the second part is preferably inserted into the first part. The second part may be formed as a sleeve. The second part may be attached to the first part in a form fit or a positive fit. Alternatively or in addition, the second part may be attached to the first part via a friction fit or via a snap fit. Preferably, the second part comprises a first axial portion, and the first part comprises an intermediate axial portion and a second axial portion. Such a configuration facilitates manufacturing, in particular by injection molding.

[0054] The receiving chamber may be formed as a receiving chamber module, in particular as a tubular sleeve, which may be inserted into the body of the aerosol generating device. Advantageously, this allows for a modular assembly of the aerosol generating device.

[0055] Alternatively, at least part of the receiving chamber may be formed integrally with the main body.By providing at least part of the receiving chamber as part of the main body, the number of usable parts for the aerosol generating device may be reduced.

[0056] At least one of the plurality of first protrusions, in particular each of them may include a rib, or may form a rib, or may be a rib. Similarly, at least one of the plurality of second protrusions, in particular each of them may include a rib, or may form a rib, or may be a rib. Preferably, one or more ribs extend in the direction of the central axis. One or more ribs extend in the direction of the central axis. In particular, the ribs may be arranged around the central axis at equal intervals. Any of these configurations is advantageous for improved airflow management of the device. As described above, the term "extending in the direction of the central axis" includes both an extension parallel to the central axis and an extension in the general direction of the central axis, which may be tilted relative to the central axis (e.g., tilted 2 to 5 degrees), but still located in a common plane corresponding to the central axis. The latter is particularly suitable for a generally conical shape of the receiving chamber, such as a conical or frustoconical shape.

[0057] One or more ribs may have a substantially triangular cross-sectional shape. Alternatively, one or more ribs may have a substantially rectangular or substantially trapezoidal or substantially semi-oval or substantially semi-circular cross-sectional shape.

[0058] The one or more ribs may comprise a contact surface, preferably adapted to the shape of a corresponding portion of the aerosol-generating article, which contact surface comes into contact with the corresponding portion of the aerosol-generating article when the article is inserted into the receiving chamber.

[0059] At least one of the plurality of first protrusions, in particular each one and / or at least one of the plurality of second protrusions, in particular each one, may be chamfered or may include at least one chamfer. Preferably, the respective protrusion may be chamfered at the side facing the insertion opening of the receiving chamber, or may include at least one chamfer facing the insertion opening of the receiving chamber. Advantageously, this facilitates the insertion of the product into the receiving chamber. Similarly, the respective protrusion may be chamfered at the side facing away from the insertion opening of the receiving chamber, or may include at least one chamfer facing away from the insertion opening of the receiving chamber. Advantageously, this facilitates the removal of the product from the receiving chamber.

[0060] The aerosol generating device may further comprise a heater for heating the aerosol-forming substrate in an aerosol-generating article received in a receiving chamber of the device. The heater may be an induction heater. The induction heater may comprise an induction source comprising an inductor configured to generate an alternating, particularly high-frequency electromagnetic field in the receiving chamber. The alternating, particularly high-frequency electromagnetic field may be in the range of 500 kHz to 30 MHz, in particular between 5 MHz to 15 MHz, preferably between 5 MHz to 10 MHz. When the article is inserted into the receiving chamber, the alternating electromagnetic field is used to inductively heat a susceptor in thermal contact or thermal proximity with the aerosol-forming substrate to be heated. The inductor may be arranged to surround at least a portion of the receiving chamber or at least a portion of the inner surface of the receiving chamber, respectively. The inductor may be an inductor coil, such as a spiral coil, arranged in a side wall of the receiving chamber. Preferably, the inductor may be arranged to surround at least the middle axial portion of the inner surface. More preferably, the inductor may be arranged to surround only the distal portion of the inner surface. Alternatively, the inductor may be arranged to additionally at least partially surround the first axial portion or the second axial portion, or both the first axial portion and the second axial portion.

[0061] Alternatively, the heater may be a resistive heater comprising a resistive heating element. The heating resistive element is configured to heat when an electric current passes through it due to the inherent ohmic resistance or resistive load of the resistive heating element. For example, the resistive heating element may comprise at least one of a resistive heating wire, a resistive heating rail, a resistive heating grid or a resistive heating mesh. When the device is in use, the resistive heating element is in thermal contact or thermal proximity with the aerosol-forming substrate to be heated.

[0062] The device may also include a power supply and a controller for powering and controlling the heating process.

[0063] The present invention also relates to an aerosol generating system comprising an aerosol generating device according to the present invention and as described herein. The system also comprises an aerosol generating article comprising at least one aerosol-forming substrate to be heated by the device, wherein at least a portion of the article is removably receivable or removably receivable in a receiving chamber of the device.

[0064] The device and article are configured such that when the article is inserted into the receiving chamber, the plurality of first protrusions and the plurality of second protrusions contact at least a portion of the aerosol-generating article for retaining the aerosol-generating article in the receiving chamber. In contrast, a middle portion of the inner surface of the receiving chamber does not contact the aerosol-generating article.

[0065] Preferably, the shape of the envelope curve around the central axis intersecting the peak of each of the plurality of first protrusions or the plurality of second protrusions, respectively, corresponds to the cross-sectional shape of the aerosol-generating article to be received in the receiving chamber.

[0066] As described above with respect to the aerosol generating device, the plurality of first protrusions and the plurality of second protrusions are spaced apart from each other so that airflow channels are formed between adjacent first protrusions and second protrusions, respectively. Advantageously, the shapes and distances of the plurality of first protrusions and the plurality of second protrusions, respectively, may be selected so that when the aerosol generating article is inserted into the receiving chamber of the device, the resistance to draw (RTD) is within a desired range. The resistance to draw (RTD) may be in the range of 70 mmWG to 120 mmWG. Preferably, the resistance to draw (RTD) may be between 40 mmWG and 70 mmWG, in particular between 45 mmWG and 65 mmWG, for example 55 mmWG.

[0067] As used herein, the term "aerosol-forming substrate" relates to a substrate that can release volatile compounds that can form an aerosol when heated. Aerosol-forming substrate can be a solid or liquid aerosol-forming substrate. Aerosol-forming substrate can include tobacco-containing material, which contains volatile tobacco flavor compounds released from substrate after heating. Alternatively or additionally, aerosol-forming substrate can include non-tobacco material. Aerosol-forming substrate can also include aerosol-forming agent. The example of suitable aerosol-forming agent is glycerine and propylene glycol. Aerosol-forming substrate can also include other additives and ingredients, such as nicotine or flavoring substances. In particular, liquid aerosol-forming substrate can include water, solvent, ethanol, plant extract and natural or artificial flavors. Aerosol-forming substrate can also be a pasty material, a porous material pouch comprising aerosol-forming substrate, or for example, loose tobacco mixed with a gelling agent or a tackifier, which can include common aerosol-forming agents such as glycerine, and then compressed or molded into a plug.

[0068] The aerosol-generating article may be a consumable, in particular a consumable intended for single use. The aerosol-generating article may be a tobacco product. In particular, the article may be a rod-shaped article, preferably a cylindrical rod-shaped article, which may be similar to a conventional cigarette.

[0069] The article may comprise one or more of the following elements: a first support element, a substrate element, a second support element, a cooling element and a filter element. Preferably, the aerosol-generating article comprises at least a first support element, a second support element and a substrate element positioned between the first support element and the second support element.

[0070] All aforementioned elements can be arranged in order along the length axis of goods according to the above order, wherein the first support element is preferably arranged at the distal end of goods, and the filter element is preferably arranged at the proximal end of goods.Each of the above-mentioned elements can be roughly cylindrical.Especially, all elements can have the same external cross-sectional shape.In addition, element can be surrounded by outer packaging material, so that element is kept together and maintain the desired cross-sectional shape of rod-shaped goods.Preferably, packaging material is made of paper.

[0071] The substrate element preferably comprises at least one aerosol-forming substrate to be heated. In the case where the aerosol generating system is based on induction heating, the substrate element may also comprise a susceptor in thermal contact or thermal proximity with the aerosol-forming substrate. As used herein, the term "susceptor" refers to an element comprising a material capable of being inductively heated within an alternating electromagnetic field. This may be the result of at least one of hysteresis losses or eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0072] At least one of the first support element and the second support element may include a central air channel. Preferably, at least one of the first support element and the second support element may include a hollow cellulose acetate tube. Alternatively, the first support element may be used to cover and protect the distal front end of the substrate element.

[0073] The aerosol-cooling element is an element with a large surface area and low resistance to draw (eg 15 mmWG to 20 mmWG).In use, an aerosol formed by volatile compounds released from the substrate element is drawn through the aerosol-cooling element before being delivered to the proximal end of the aerosol-generating article.

[0074] The filter element is preferably used as a mouthpiece, or as part of a mouthpiece together with an aerosol-cooling element.As used herein, the term "mouthpiece" refers to the part of the article through which the aerosol leaves the aerosol-generating article.

[0075] Preferably, when the article is received in the receiving chamber, the first support element contacts or is configured to contact the first axial portion of the inner surface of the receiving chamber. Similarly, when the article is received in the receiving chamber, the second support element contacts the second axial portion of the inner surface of the receiving chamber, or is configured to contact the second axial portion of the inner surface of the receiving chamber. In contrast, the substrate element is preferably surrounded by the middle axial portion of the inner surface when the article is received in the receiving chamber or is configured to be surrounded by the middle axial portion, however, it does not contact the middle axial portion. In addition, the substrate element may be at least partially in contact with at least one of the first axial portion and the second axial portion, or may be configured to be at least partially in contact with at least one of the first axial portion and the second axial portion. As used herein, the term "contacting with..." should be understood as causing the first support element or the second support element to contact the first axial portion or the second axial portion, respectively, regardless of whether the corresponding support element is surrounded by packaging material.

[0076] Preferably, the first support element may have a length in the direction along the length axis of the rod-shaped article, which corresponds to the length of the first axial portion along the central axis of the receiving chamber. Similarly, the second support element may have a length in the direction along the length axis of the rod-shaped article, which corresponds to the length of the second axial portion along the central axis of the receiving chamber. Therefore, the substrate element may have a length in the direction along the length axis of the rod-shaped article, which corresponds to the length of the intermediate axial portion along the central axis of the receiving chamber. Alternatively, the length of at least one of the first axial portion and the second axial portion may be greater than the length of the first support element or the second support element, respectively, so as to at least partially contact the intermediate axial portion.

[0077] Any of the above configurations is advantageous for the following reasons: Firstly, the substrate element is spaced apart from the intermediate axial portion and is therefore less susceptible to condensate formation. Furthermore, the first and second protrusions of the first and second axial portions advantageously engage those portions of the article that are most rigid and tend to contract least during use. Thereby, the article is securely retained within the receiving chamber without the risk of displacement or falling out of the device.

[0078] Further features and advantages of aerosol-generating systems and aerosol-generating articles according to the invention have been described above with respect to aerosol-generating devices, and apply equally. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0080] Figure 1 An exemplary embodiment of an aerosol generating device according to the present invention is schematically shown in cross-section;

[0081] Figure 2 The perspective view schematically shows the Figure 1 A receiving chamber module of a device and an aerosol generating article introduced therein;

[0082] Figure 3 The perspective cross-sectional view schematically shows the Figure 2 A receiving chamber module and an aerosol generating article;

[0083] Figure 4 Schematically shows the Figure 2 a receiving chamber module without an aerosol generating article;

[0084] Figure 5 Schematically shows the Figure 2 a cross-sectional view of a receiving chamber; and

[0085] Figure 6 Schematically shows the Figure 4 Front view of the receiving room. DETAILED DESCRIPTION

[0086] Figure 1 An exemplary embodiment of an aerosol generating device 200 according to the present invention is schematically shown. The aerosol generating device 200 has an elongated shape and comprises a main body 210 and a receiving chamber module 220. The chamber module 220 comprises a receiving chamber 1 for receiving at least a portion of an aerosol generating article 2. The receiving chamber module 220 is inserted into a cavity 230 formed in a proximal portion 211 of the main body 210. In the distal portion 212, the main body 210 comprises a power source 250 and a controller 260 for powering the device 200 and controlling its operation. The aerosol generating device 200 and the aerosol generating article 2 together form an aerosol generating system according to the present invention.

[0087] In a proximal portion 211 of the body 210 forming the cavity 230, the aerosol generating device 200 comprises an inductor 240. In the present embodiment, the inductor 240 is a helical coil arranged around the receiving chamber 1. The inductor 240 is part of an induction heater powered and operated by a power supply 250 and a controller 260. When the device is in use, when an article 2 is received in the receiving chamber 1, the inductor 240 generates an alternating electromagnetic field in the receiving chamber 1 to inductively heat an aerosol-forming substrate contained in the article.

[0088] Figure 2 , Figure 3 and Figure 4Different aspects of the receiving chamber module 220 are shown with and without an aerosol generating article 2. As can be seen, the receiving chamber module 220 is an elongated sleeve comprising an insertion opening 15 through which the aerosol generating article 2 can be at least partially inserted into the receiving chamber 1. The insertion direction of the aerosol generating article 2 extends substantially along the central axis 201 of the receiving chamber 1. The receiving chamber 1 is made of polyetheretherketone (PEEK). The receiving chamber 1 has a generally cylindrical shape with a generally circular cross-section of a diameter of about 15 mm.

[0089] Corresponding to the shape of the receiving chamber 1, the aerosol-generating article 2 also has a generally cylindrical rod shape. Figure 1 and Figure 3 , the article 2 includes five elements arranged in sequence along the length axis of the article 2: a first support element 25, a substrate element 24, a second support element 23 including a central air channel 26, a cooling element 22 and a filter element 21. The first support element 25 is arranged at the distal end of the article 2, and the filter element 21 is arranged at the proximal end of the article 2. Each of the aforementioned elements 21, 22, 23, 24, 25 is generally cylindrical, and all of them have the same external cross-sectional shape. In addition, the elements are surrounded by an outer packaging material so as to keep the elements together and maintain the desired circular cross-sectional shape of the rod-shaped article 2. Preferably, the packaging material is made of paper. The first support element 25 is used to cover and protect the distal front end of the substrate element 24. The substrate element 24 includes at least one aerosol-forming substrate to be heated. In addition, the substrate element 24 also includes an inductor (not shown) in thermal contact with the aerosol-forming substrate. When the inductor 240 is activated, the inductor is heated due to at least one of eddy currents or hysteresis losses caused by the electromagnetic field, depending on the electrical and magnetic properties of the inductor material. The susceptor is heated until a temperature sufficient to evaporate the material from the aerosol-forming substrate is reached. The released material may be entrained in the airflow passing through the article 2 from the first support element 25 through the substrate element 24, the second support element 23 and the cooling element 22 toward the filter element 21. Along the way, the evaporated material cools to form an aerosol and then escapes through the filter element 21 at the proximal end of the article 2.

[0090] Figure 5 More details of the receiving chamber module 220 and the receiving chamber 1 are shown, respectively. The receiving chamber 1 includes an inner surface 16, which extends over the entire axial length of the receiving chamber 1. In the present embodiment, the axial length of the receiving chamber 1 is in the range of 25 mm to 28 mm. Along the central axis 201 of the receiving chamber 1, the inner surface 16 includes a first axial portion 11, a second axial portion 13, and an intermediate axial portion 12 positioned between the first axial portion 11 and the second axial portion 13. The length of the intermediate axial portion 12 is about 33% (about one third) of the axial length of the receiving chamber 1. As shown in FIG. Figure 5 As can be further seen in the figure, the receiving chamber module 220 or the receiving chamber 1, respectively, is a multi-part component comprising a first part 221 and a second part 222. The second part 222 is formed as a sleeve and is inserted into the first part 221. The second part 222 can be attached to the first part 221 via a form fit or in a positive fit manner or a friction fit or a snap fit. The second part 221 comprises a second axial portion 13, while the first part comprises an intermediate axial portion 12 and a second axial portion 13. Such a modular construction facilitates manufacturing, in particular by injection molding.

[0091] The first axial portion 11 includes a plurality of first protrusions 10, for example, twelve first protrusions 10. Similarly, the second axial portion 13 includes a plurality of second protrusions 17, for example, twelve second protrusions 17. In contrast, the intermediate axial portion 12 does not include any protrusions, but is flat. Therefore, the plurality of first protrusions 10 and the plurality of second protrusions 17 extend beyond the intermediate axial portion 12 in a radially inward direction toward the central axis 201. Therefore, when the product 2 is inserted into the receiving cavity 1, the product 2 only contacts the plurality of first protrusions 10 and the plurality of second protrusions 17. In contrast, as Figure 1 As can be seen in particular, the article 2 is not in contact with the intermediate axial portion 12 of the inner surface 16. As a result, the total contact area between the article 2 and the inner surface 16 of the receiving chamber 1 is significantly reduced. Advantageously, this results in an overall reduction in heat losses due to direct heat conduction from the aerosol-generating article 2 to the inner surface 16. Furthermore, adverse effects on the article due to condensate formation in the chamber 1 are also reduced.

[0092] Despite the reduced contact area between the article 2 and the inner surface 16, the article 2 is still firmly held in the receiving chamber 1 by the first protrusion 10 and the second protrusion 17. This applies all the more in the present embodiment since the arrangement and dimensions of the first axial portion 11, the second axial portion 12 and the intermediate axial portion 13 on the one hand and the arrangement and dimensions of the first support element 25, the substrate element 24 and the second support element 23 on the other hand are adapted to one another. Figure 1 and Figure 31 , it can be seen that, when the article 2 is received in the chamber 1 , the first support element 25 is in contact with the first protrusions 10 of the first axial portion 11 and the second support element 23 is in contact with the second protrusions 17 of the second axial portion 13. In contrast, the substrate element 24 is substantially surrounded by the intermediate axial portion 12, however, without any contact therewith. Only at its very axial ends is the substrate element 24 partially in contact with the first protrusions 10 of the first axial portion 11 and the second protrusions 17 of the second axial portion 13. Due to this particular configuration, the first protrusions 10 and the second protrusions 17 of the first axial portion 11 and the second axial portion 13 are substantially engaged only with those parts of the article 2 which are most rigid and tend to contract the least during use, that is to say, with the first support element 23 and the second support element 25.

[0093] As mentioned above, when masking the first protrusions 10 and the second protrusions 17, the receiving chamber 1 has a substantially cylindrical shape, which refers to the shape of the receiving chamber 1. Therefore, the area of ​​the first axial portion 11, in particular the area between adjacent first protrusions 10, and the area of ​​the second axial portion 13, in particular the area between adjacent second protrusions 17 and the area of ​​the middle portion are arranged on a common cylindrical housing surface.

[0094] In the present embodiment, the first protrusion and the second protrusion are formed as ribs extending in a direction parallel to the central axis 201. The twelve ribs of each of the first axial portion 11 and the second axial portion 13 are symmetrically arranged around the central axis 201 and are equally spaced from each other. The spacing between adjacent ribs is in the range of 1.3 mm to 1.5 mm. With respect to its length extension, each rib is chamfered or includes corresponding chamfers at both ends, that is, at the side facing the insertion opening 15 and at the opposite side away from the insertion opening 15. Advantageously, the chamfers facilitate the insertion and removal of the aerosol generating article 2 into the receiving chamber 1. In addition to this, each rib has a constant height extension along its length extension. In the present embodiment, the height is in the range of 0.4 mm to 0.5 mm as measured in a radial direction towards the central axis 201.

[0095] like Figure 6 , each rib has a generally rectangular cross-sectional shape as seen in a plane perpendicular to the central axis 201. The edge 31 of each rib extending along its length is rounded to avoid cutting the packaging material of the aerosol generating article 2 during insertion and removal of the article 2.

[0096] like Figure 5It can be further seen that the first protrusions 10 of the first axial portion 11 and the second protrusions 17 of the second axial portion 13 are in line, that is, as seen in a direction parallel to the central axis 201, each of the first protrusions 10 is aligned with a corresponding one of the second protrusions 17. As a result, the gaps 32 between adjacent first protrusions 10 and between adjacent second protrusions 17 advantageously form multi-groove airflow channels (see Figure 5 ), the multi-groove airflow channel extends from the insertion opening 15 at the proximal end 4 of the receiving chamber 1 to the bottom at the distal end 5 of the receiving chamber 1.

[0097] Thus, when negative pressure is applied at the filter element 21 of the aerosol-generating article 2 received in the receiving chamber 1, for example when the user draws a puff, air is sucked into the receiving chamber 1 at the edge of the insertion opening 15 and further along the multi-grooved airflow channel into the bottom portion at the distal end 4 of the receiving chamber 1. There, the airflow enters the aerosol-generating article 2 through the first support element 25 and further passes through the substrate element 24, the second support element 23, the aerosol-cooling element 22 and the filter element 21, where it finally leaves the article 2. In the substrate element 24A, the vaporized material from the aerosol-forming substrate is entrained in the airflow and subsequently cooled as it further passes through the second support element 23, the aerosol-cooling element 22 and the filter element 21, so as to form an aerosol.

[0098] In order to be able to properly redirect the airflow into the aerosol-generating article 2 at the bottom portion of the receiving chamber 1, the aerosol-generating device 200 according to the present embodiment comprises three end stops 14 arranged at the distal end 5 of the receiving chamber 1. The end stops 14 are configured to limit the insertion depth of the article 2 into the receiving chamber 1 and thus prevent the article 2 from abutting against the bottom surface of the receiving chamber 1. This is shown in Figure 1 middle.

[0099] like Figure 5 As can be seen in FIG. 1 , the three end stops 14 are formed as annular segments which are symmetrically and equally spaced around the central axis 201 at the inner circumference of the receiving chamber 1. Each annular segment 14 has a height dimension in the direction of the central axis 201 in the range of 1 mm to 3 mm (e.g. 1.4 mm), and has a radial dimension as measured in the radial direction toward the central axis 201 in the range of 1 mm to 2 mm (e.g. 1.3 mm).

[0100] like Figure 5It can be further seen that the end stop 14 covers or blocks some grooves of the airflow channel defined by the gap 32 between adjacent first protrusions 10 and adjacent second protrusions 17. Therefore, the airflow passing between the product 2, the plurality of first protrusions 10 and the plurality of second protrusions 17 is reduced compared to the airflow passing between the product 2, the plurality of first protrusions 10 and the plurality of second protrusions 17 in the absence of the end stop 14. Therefore, the suction resistance of the system is also increased compared to the system without the end stop. When the device is used, the suction resistance can be in the range of 70 mmWG to 120 mmWG. Preferably, the suction resistance (RTD) can be between 40 mmWG and 70 mmWG, in particular between 45 mmWG and 65 mmWG, for example between 55 mmWG. In order to ensure a reasonable minimum airflow and a reasonable resistance to suction, the number, shape and size of the end stops are preferably selected so that the (reduced) airflow is at least 50%, in particular at least 60%, preferably at least 70%, even more preferably at least 80% of the airflow in the absence of the end stops. This can be achieved by selecting the number, shape and size of the end stops so that the end stops cover at most 50%, in particular at most 40%, preferably at most 30%, even more preferably at most 20% of the total cross-sectional area of ​​all gaps 32 defined between adjacent first protrusions 10 or between adjacent second protrusions 17 as seen in a plane perpendicular to the central axis. In the present embodiment, when considering the coverage of the end stops 14, the total cross-sectional area of ​​all gaps 32 defined between adjacent first protrusions 10 or between adjacent second protrusions 17 is about 4.5 square millimeters, while in the absence of the end stops 14 it is about 7.2 square millimeters.

Claims

1. An aerosol generating device for use with an aerosol generating article, the aerosol generating device comprising a receiving chamber for removably receiving at least a portion of the aerosol generating article, the receiving chamber having an inner surface and a central axis, wherein along the central axis, the inner surface comprises a first axial portion, a second axial portion, and an intermediate axial portion positioned between the first axial portion and the second axial portion, wherein the first axial portion comprises a plurality of first protrusions, and the second axial portion comprises a plurality of second protrusions, wherein the plurality of first protrusions and the plurality of second protrusions are configured to contact a first supporting element and a second supporting element of the aerosol generating article, respectively, for retaining the aerosol generating article in the receiving chamber, wherein the plurality of first protrusions and the plurality of second protrusions extend beyond the intermediate axial portion in a direction toward the central axis, wherein the intermediate axial portion has a length of at least 20% of the total length of the inner surface or the receiving chamber in the direction of the central axis and is configured to surround a substrate element of the aerosol generating article when the aerosol generating article is received in the receiving chamber.

2. An aerosol generating device according to claim 1, wherein the intermediate axial portion is free of any protrusions.

3. An aerosol generating device according to claim 1 or 2, wherein at least one first protrusion of the plurality of first protrusions or at least one second protrusion of the plurality of second protrusions extends in a direction substantially along the central axis of the receiving chamber.

4. An aerosol generating device according to claim 1 or 2, further comprising one or more end stops arranged at the distal end of the receiving chamber.

5. An aerosol generating device according to claim 4, wherein at least one of the number, shape and size of the one or more end stops is selected so that the one or more end stops increase the suction resistance by up to 50% compared to the aerosol generating device without any end stops.

6. An aerosol generating device according to claim 4, wherein the one or more end stops cover at most 50% of the total cross-sectional area of ​​all gaps defined between adjacent first protrusions or between adjacent second protrusions as seen in a plane perpendicular to the central axis.

7. An aerosol generating device according to claim 4, wherein the one or more end stops are formed as ring segments.

8. An aerosol generating device according to claim 1 or 2, wherein at least one first protrusion of the plurality of first protrusions or at least one second protrusion of the plurality of second protrusions has a constant radial distance from the central axis over the corresponding length of the corresponding protrusion.

9. An aerosol generating device according to claim 1 or 2, wherein the receiving chamber comprises a first part and a second part, wherein the second part is inserted into the first part, and wherein the second part is formed as a sleeve including the second axial part, and the first part includes the first axial part.

10. An aerosol generating device according to claim 1 or 2, wherein the receiving chamber is formed as a sleeve and is inserted into a body of the aerosol generating device.

11. An aerosol generating device according to claim 1 or 2, wherein at least one of the plurality of first protrusions and the plurality of second protrusions is formed as a rib extending in an axial direction relative to the central axis.

12. An aerosol generating device according to claim 1 or 2, wherein at least one of the plurality of first protrusions and the plurality of second protrusions is chamfered at at least one of a side facing the insertion opening of the receiving chamber and an opposite side facing away from the insertion opening of the receiving chamber.

13. An aerosol generating system, comprising an aerosol generating device according to any one of claims 1 to 12 and an aerosol generating article having an aerosol-forming substrate, wherein at least a portion of the aerosol generating article is removably received or capable of being removably received in the receiving chamber of the aerosol generating device.

14. An aerosol generating system according to claim 13, wherein the aerosol generating product includes at least a first support element, a second support element and a substrate element, the substrate element includes the aerosol-forming substrate and is positioned between the first support element and the second support element, and wherein when the aerosol generating product is received in the receiving chamber, the first support element is in contact with the first axial portion, and the second support element is in contact with the second axial portion, and the substrate element is surrounded by the intermediate axial portion without contacting the intermediate axial portion.

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