Aerosol-generating article with a main reservoir and a capillary buffer reservoir

Abstract

The present invention relates to an aerosol-generating article for use with an aerosol-generating device. The article comprises a main reservoir for storing an aerosol-forming liquid and a capillary buffer reservoir in fluid communication with the main reservoir for storing the aerosol-forming liquid due to capillary action. The article further comprises a liquid conduit in fluid communication with at least the capillary buffer reservoir for providing aerosol-forming liquid at an interface between the capillary buffer reservoir and the main reservoir to the exterior. The present invention also relates to an aerosol-generating system comprising such an article and an aerosol-generating device for use with the article.

Description

[Technical Field]

[0001] The present disclosure relates to an aerosol-generating article for use with an aerosol-generating device, the article comprising at least one liquid reservoir for storing an aerosol-forming liquid. The present disclosure also relates to an aerosol-generating system comprising such an article and an aerosol-generating device for use with the article. [Background technology]

[0002] It is generally known in the art to generate inhalable aerosols by heating an aerosol-forming liquid. To this end, the liquid aerosol-forming substrate may be transported from a liquid reservoir to an area external to the reservoir by a liquid conduit, e.g., a wick element. There, the liquid may be vaporized by a heater and then exposed to an air path to form the inhalable aerosol. Both the liquid reservoir and the liquid conduit may be part of an aerosol-generating article configured to be inserted into an aerosol-generating device to vaporize the aerosol-forming liquid stored in the article.

[0003] Practice has shown that aerosol generation using such systems sometimes does not work reliably. In particular, aerosol generation can depend on the position in which the aerosol generation system is held by the user during operation.

[0004] It would therefore be desirable to have an aerosol-generating article and an aerosol-generating system for generating aerosols from aerosol-forming liquids that have the advantages of the prior art solutions while mitigating the limitations of the prior art. In particular, it would be desirable to have an aerosol-generating article and an aerosol-generating system that reliably generates aerosols from aerosol-forming liquids. Summary of the Invention

[0005] According to the present invention, there is provided an aerosol-generating article for use with an aerosol-generating device, the article comprising a main reservoir for storing an aerosol-forming liquid, and a capillary buffer reservoir in fluid communication with the main reservoir for storing the aerosol-forming liquid due to capillary action, the article further comprising a liquid conduit in fluid communication with at least the capillary buffer reservoir for providing the aerosol-forming liquid at an interface between the capillary buffer reservoir and the main reservoir to the exterior.

[0006] According to the present invention, it has been found that aerosol generation is insufficient in many systems due to the fact that the liquid conduit is only properly submerged in the aerosol-forming liquid at certain positions. However, at certain positions, for example, when the aerosol generation system is turned upside down, the aerosol-forming liquid may shift position within the reservoir, so that the liquid conduit is no longer in contact with the liquid. As a result, delivery of the aerosol-forming liquid to the vaporization zone outside the reservoir is interrupted, causing a rapid decline in aerosol formation or even failure. In addition, due to the lack of aerosol-forming liquid, the liquid conduit may overheat in the vaporization zone, which may then cause the generation of harmful components from either the aerosol-forming liquid or the article material.

[0007] To remedy this, the present invention proposes the use of a small-volume capillary buffer reservoir in fluid communication with the main reservoir and the liquid conduit. The buffer reservoir is configured to store aerosol-forming liquid due to capillary action, ensuring a sufficient amount of aerosol-forming liquid is provided to the liquid conduit in fluid communication with the buffer reservoir, independent of the article position. To this extent, it has been found that if the volume of the capillary buffer reservoir is chosen small enough, the capillary effect dominates over gravity. As a result, after the aerosol-forming liquid has filled the buffer reservoir, it is prevented from flowing back into the main reservoir, particularly if the orientation of the article is changed, for example, from a substantially upright position to a substantially horizontal position, or even an upside-down position. Essentially, the capillary buffer reservoir of the aerosol-generating article according to the present invention acts like the buffer reservoir of a fountain pen.

[0008] In theory, capillary lengths would be expected to vary significantly for liquids with different surface tensions and densities. However, in practice, capillary lengths are typically only a few millimeters for most liquids. The reasons for this narrow range of capillary lengths for different liquids are, among other factors, surface imperfections, contact angle hysteresis, and surface cleanliness. Therefore, the dimensions of the capillary buffer reservoir can be selected so that the maximum dimension between two opposing walls defining at least a portion of the capillary buffer reservoir is within the range of 0.2 to 5 millimeters, particularly 0.5 to 3 millimeters, and preferably 1 to 2.5 millimeters. These values ​​ensure sufficient capillary action while still providing a sufficiently large buffer volume for storing a sufficient amount of aerosol-forming liquid. In particular, it has been found that it is sufficient for only one dimension of the buffer reservoir to be smaller than the effective capillary length. In particular, the capillary action of the buffer reservoir may be due to the maximum dimension between two opposing walls that define at least a portion of the capillary buffer reservoir being in the range of 0.2 mm to 5 mm, in particular 0.5 mm to 3 mm, preferably 1 mm to 2.5 mm.

[0009] The capillary buffer reservoir may have a total volume of up to 60 cubic millimeters, in particular up to 50 cubic millimeters, preferably up to 40 cubic millimeters, more preferably up to 30 cubic millimeters, and most preferably up to 20 cubic millimeters, which still ensure adequate capillary action.

[0010] Conversely, the total volume of the capillary buffer reservoir may be at least 5 cubic millimeters, in particular at least 10 cubic millimeters, and preferably at least 15 cubic millimeters, which volumes are large enough to still provide a sufficient amount of aerosol-forming liquid trapped within the capillary buffer reservoir to last for at least several puffs.

[0011] The capillary buffer reservoir comprises a lamellar structure, the use of which advantageously increases the inner surface of the buffer reservoir and thus increases capillary action, essentially acting like the lamellae of a fountain pen.

[0012] In particular, the lamellar structure may comprise a plurality of lamellae, which may be arranged adjacent to one another, in particular in a side-by-side configuration, with gaps between them. As generally discussed above with respect to the maximum dimension between opposing walls of the buffer reservoir, the maximum dimension between adjacent lamellae may advantageously be in the range of 0.2 to 5 mm, in particular 0.5 to 2.5 mm, preferably 1 to 2 mm.

[0013] In particular, the buffer reservoir may be free of any capillary material and liquid-retaining material. More specifically, the buffer reservoir may be a hollow or empty space unless it is filled with an aerosol-forming liquid.

[0014] In general, the main reservoir and the capillary buffer reservoir may be in fluid communication with each other in different ways.

[0015] As an example, the main reservoir may open directly into the capillary buffer reservoir. That is, the main reservoir and the capillary buffer reservoir may together form a common reservoir, with each one of the main reservoir and the capillary buffer forming part of the common reservoir. Advantageously, such an arrangement is easy and cheap to manufacture.

[0016] As another example, the main reservoir and the capillary buffer reservoir can be in fluid communication with each other via at least the first liquid channel. In this configuration, the main reservoir and the capillary buffer reservoir are isolated from each other and fluidly connected only by at least the first liquid channel. Advantageously, this configuration can slow the reflux of aerosol-forming liquid from the capillary buffer reservoir to the main reservoir, particularly if capillary action is temporarily insufficient to adequately confine the aerosol-forming liquid within the capillary buffer reservoir.

[0017] The first liquid channel may be configured to redirect the flow of liquid through the article by at least 90 degrees, particularly 180 degrees, allowing for a compact design of the aerosol-generating article with the main reservoir and capillary buffer reservoir disposed adjacent to one another.

[0018] In addition to the first liquid channel, the main reservoir and the capillary buffer reservoir may also be in fluid communication with one another via at least a second liquid channel, which can particularly facilitate refilling of the capillary buffer reservoir from the main reservoir during or after depletion of the aerosol-forming liquid in the capillary buffer reservoir via a liquid conduit, which is a use of the aerosol-generating system.

[0019] Advantageously, at least one of the first and second fluid channels can also serve as a capillary buffer for the aerosol-forming liquid. Thus, the maximum dimension between two opposing walls defining at least a portion of at least one of the first or second fluid channels, respectively, can be in the range of 0.2 to 5 mm, particularly 0.5 to 4 mm, preferably 1 to 3 mm, and most preferably 2 to 3 mm. In particular, the diameter of at least one of the first and second fluid channels can be in the range of 0.2 to 5 mm, particularly 0.5 to 4 mm, preferably 1 to 3 mm, and most preferably 2 to 3 mm.

[0020] The capillary buffer reservoir is preferably downstream of the main reservoir with respect to the flow of liquid through the article. Similarly, the liquid conduit is preferably downstream of the capillary buffer reservoir with respect to the flow of liquid through the article.

[0021] Furthermore, with respect to the flow of liquid through the article, at least a portion of the fluid conduit is disposed at or within a downstream portion of the capillary buffer reservoir. Advantageously, this arrangement ensures that the liquid conduit is adequately submerged in the aerosol-forming liquid confined within the capillary buffer reservoir. This in turn ensures adequate delivery of the aerosol-forming liquid from the buffer reservoir to the main reservoir and to regions external to the buffer reservoir where the aerosol-forming liquid can be vaporized.

[0022] In particular, the main reservoir, the buffer reservoir, and the heating zone may be fluidly connected in series.

[0023] As already further mentioned above, the capillary buffer reservoir may be arranged adjacent to the main reservoir. This arrangement has proven advantageous with regard to the compact design of the aerosol-generating article, especially with regard to the short length dimensions of the aerosol-generating article. A compact design is particularly preferred with regard to the fact that the aerosol-generating article according to the invention is preferably used with a handheld aerosol generating device.

[0024] The aerosol-generating article may have a simple design. The article may have an article housing comprising a main reservoir and a capillary buffer reservoir. The housing is preferably a rigid housing comprising a material impermeable to liquids. As used herein, "rigid housing" means a free-standing housing. The housing may comprise or be made from one of PEEK (polyetheretherketone), PP (polypropylene), PE (polyethylene), or PET (polyethylene terephthalate). PP, PE, and PET are particularly cost-effective and easy to mold, especially extrusion. The housing may also include a flexible or collapsible section. The housing may further include at least one breathing hole for volume compensation.

[0025] In particular, the aerosol-generating article may include a partition wall that defines both at least a portion of the main reservoir and at least a portion of the capillary buffer reservoir. This configuration further enhances the compact article design. The partition wall may be part of the article housing.

[0026] Furthermore, at least a portion of the main reservoir and at least a portion of the capillary buffer reservoir can be formed integrally with one another, making the aerosol-generating article particularly easy and inexpensive to manufacture. For example, at least a portion of the main reservoir and the capillary buffer reservoir, the reservoir body, can be integrally formed as an extruded reservoir body, particularly a one-piece extruded reservoir body.

[0027] To further enhance delivery of vaporized aerosol-forming liquid to regions external to the main reservoir and capillary buffer reservoir, the liquid conduit may also be in direct fluid communication with the main reservoir, i.e., the liquid to be counted may be in fluid communication with both the capillary buffer reservoir and the main reservoir.

[0028] To fluidly connect the liquid conduit with the main reservoir, the aerosol-generating article may include a bypass channel that bypasses the main reservoir and provides direct fluid communication between the main reservoir and the fluid conduit.

[0029] Alternatively or additionally, the aerosol-generating article may comprise three intersecting fluid channels, each of which is connected to one of the main reservoir, the capillary buffer reservoir, and the fluid conduit to provide nodal fluid communication between each two of the main reservoirs, the capillary buffer reservoirs, and the fluid conduits.

[0030] As mentioned above, at least a portion of the fluid conduit may be disposed downstream of or within the capillary buffer reservoir. To that end, the liquid conduit may pass through a wall defining at least a portion of the capillary buffer reservoir. The wall may be, for example, a separation wall or a bushing separating the capillary buffer reservoir from a vaporization zone. The vaporization zone may be a zone through which the aerosol-forming liquid is conveyed by the liquid conduit and into which the conveyed aerosol-forming liquid is vaporized upon use of the article in an aerosol-generating device. Thus, the aerosol-generating article may comprise a vaporization zone, in particular a vaporization cavity for vaporizing the aerosol-forming liquid.

[0031] To provide the aerosol-forming liquid within the vaporization zone, the liquid conduit may pass through or face the vaporization zone. As used herein, the term "facing the vaporization cavity" refers to a configuration in which the liquid conduit is in fluid communication with, but does not pass through, the vaporization zone.

[0032] Generally, the liquid conduit may have any shape and configuration suitable for transporting liquid from the capillary buffer reservoir to the vaporization zone. In particular, the liquid conduit may include a wicking element. The wicking element may be configured as stranded wire with sufficient porosity, a rope of stranded material, a mesh, a mesh tube, several concentric mesh tubes, a fabric, a sheet of material, or foam (or other porous solid), a roll of fine metal mesh, or some other arrangement of metal foil, fiber, or mesh, or any other shape appropriately sized and configured to perform the wicking action described herein.

[0033] The liquid conduit, particularly the core element, may include a filament bundle containing a plurality of filaments. The filament bundle is preferably a non-stranded filament bundle. In a non-stranded filament bundle, the filaments of the filament bundle extend adjacent to each other without crossing each other, preferably along the entire length of the filament bundle. Similarly, the filament bundle may include a stranded portion in which the filaments of the filament bundle are stranded. The stranded portion may enhance the mechanical stability of the filament bundle.

[0034] As an example, a bundle of filaments may include a parallel-bundle portion along at least a portion of its length extension, where multiple filaments may be arranged parallel to one another. The parallel-bundle portion may be disposed at one end portion of the bundle of filaments or between both end portions of the bundle of filaments. Alternatively, the parallel-bundle portion may extend along the entire length dimension of the bundle of filaments.

[0035] As another example, the bundle of filaments may include a first immersed section, a second immersed section, and an intermediate section between the first and second immersed sections. Along at least the intermediate section, the filaments may be arranged parallel to one another. For a particular configuration of the article having a buffer reservoir and a vaporization zone, each of the first immersed section and the second immersed section may be at least partially disposed within the capillary buffer reservoir, and the intermediate section may be disposed within a region outside the capillary buffer reservoir, particularly within the vaporization zone.

[0036] The use of filaments to transport liquids is particularly advantageous because filaments inherently provide capillary action. Furthermore, in bundles of filaments, capillary action is further enhanced due to the narrow spaces formed between the filaments when bundled. This is particularly true for parallel arrangements of filaments, along which capillary action is constant because the narrow spaces between the filaments do not change along the parallel arrangement.

[0037] The filaments are preferably solid material filaments. Solid material filaments are inexpensive and easy to manufacture. In addition, solid material filaments provide good mechanical stability, thus making the filament bundles sturdy. Generally, they may have any cross-sectional shape suitable for transporting the aerosol-forming liquid, especially when bundled. Thus, the filaments may have a circular, elliptical, oval, triangular, rectangular, square, hexagonal, or polygonal cross-section. Preferably, the filaments have a substantially circular, oval, or elliptical cross-section. With such a cross-section, the filaments are in line contact with each other rather than area contact, forming capillary spaces between them.

[0038] Capillary action generally depends on the reduction in surface energy between two distinct surfaces, the liquid surface and the solid surface of the filament, to form a drop. Capillary action includes effects that depend on the radii of curvature of both the liquid surface and the filament. Thus, there may be a need for a large surface area and a small radius of curvature, both of which are achieved by a small diameter of the filament. Thus, the plurality of first filaments may have a diameter of at most 0.025 mm, at most 0.05 mm, at most 0.1 mm, at most 0.15 mm, at most 0.2 mm, at most 0.25 mm, at most 0.3 mm, at most 0.35 mm, at most 0.4 mm, at most 0.45 mm, or at most 0.5 mm.

[0039] Generally, the filament bundle may be a linear filament bundle, i.e., a substantially straight, non-curved or non-bending filament bundle. This configuration does not exclude slight bending of the filament bundle, i.e., a large radius of curvature along the length extension of the filament bundle. As used herein, a large radius of curvature may include a radius of curvature that is 10 times, particularly 20 times, or 50 times, or particularly 100 times greater than the total length of the filament bundle. Alternatively, the filament bundle may be curved. In particular, the filament bundle may be substantially U-shaped, C-shaped, or V-shaped.

[0040] The filaments may be surface-treated. In particular, the filaments may at least partially include a surface coating, such as an aerosolization-enhancing surface coating, a liquid-adhesive surface coating, a liquid-repellent surface coating, or an antibacterial surface coating. The aerosolization-enhancing surface coating may advantageously enhance various user experiences, among other things. A liquid-adhesive surface coating may be beneficial in terms of enhancing capillary action in the filament bundle. An antibacterial surface coating may function to reduce bacterial contamination. A liquid-repellent surface coating, especially at the tips of the filaments, may prevent liquid dripping.

[0041] Depending on the available space, the dimensions of the filaments, and the amount of aerosol-forming liquid to be conveyed and heated, the bundle of filaments may contain 3 to 100 filaments, in particular 10 to 80 filaments, preferably 20 to 60 filaments, more preferably 30 to 50 filaments, for example 40 filaments.

[0042] As yet another example, the liquid conduit may include two filament arrays that partially intersect each other. In particular, the liquid conduit may include an array of longitudinal filaments arranged side by side and an array of transverse filaments arranged side by side and intersecting the array of longitudinal filaments transversely to the longitudinal filament length extension. The array of transverse filaments may extend only along a portion of the length of the longitudinal filaments, such that the liquid conduit includes at least one grid portion and at least one non-grid portion. As an example, the array of longitudinal filaments may have a substantially cylindrical shape, particularly a hollow cylindrical shape. As another example, the array of longitudinal filaments may have a substantially conical or substantially frustoconical shape, particularly a substantially hollow conical or substantially hollow frustoconical shape. In any of these configurations, the longitudinal filaments form a cylindrical, conical, frustoconical, hollow cylindrical, hollow conical, or hollow frustoconical shell surface, respectively. The length axis of each shape extends substantially along the longitudinal filament length extension. Advantageously, any of the aforementioned shapes provide inherent mechanical dimensional stability. The array of transverse filaments preferably has a substantially ring shape in any of these configurations. That is, the transverse filaments extend along the periphery of a cylindrical, conical, frustoconical, hollow cylindrical, hollow conical, or hollow frustoconical shaped array of longitudinal filaments in the grid portion of the susceptor assembly. Overall, the susceptor assembly has a substantially crown shape in any of the aforementioned configurations. Furthermore, in the case of a conical, frustoconical, hollow conical, or hollow frustoconical shape, the longitudinal filaments diverge from each other toward the base of the respective shape. Thus, a conical, frustoconical, hollow conical, or hollow conical shaped array of longitudinal filaments facilitates the provision of a fan-out section.

[0043] Preferably, the liquid conduit may be inductively heatable. For example, the liquid conduit may include or be one of a bundle of inductively heatable filaments. In this manner, the liquid conduit advantageously has the ability to perform both the functions of transporting and heating the aerosol-forming liquid. Advantageously, this dual function allows for a highly material-saving and compact design of the liquid conduit without separate means for transport and heating. Additionally, there is direct thermal contact between the heat source, i.e., the liquid conduit and the aerosol-forming liquid attached thereto. Unlike when a heater contacts a saturated wick, direct contact between the liquid conduit and a small amount of liquid advantageously allows for flash heating, i.e., rapid onset of evaporation. In this regard, the liquid conduit may be considered to be or include a liquid-transport susceptor assembly. As used herein, the term "inductively heatable" refers to a liquid conduit that includes a susceptor material capable of converting electromagnetic energy into heat when subjected to an alternating magnetic field. This can be the result of at least one of hysteresis loss and eddy currents induced in the susceptor material depending on its electrical and magnetic properties. Hysteresis loss occurs in ferromagnetic or ferrimagnetic susceptor materials due to magnetic domains in the material being switched under the influence of an alternating electromagnetic field. Eddy currents are induced in conductive susceptor materials. In the case of conductive ferromagnetic or ferrimagnetic susceptor materials, both eddy currents and hysteresis loss generate heat.

[0044] Thus, the inductively heatable liquid conduit may include at least a first susceptor material, which may include or be made of a material that is at least one of electrically conductive and ferromagnetic or ferrimagnetic, respectively, i.e., the first susceptor material may include or be made of a ferrimagnetic material, a ferromagnetic material, or an electrically conductive material, or one of an electrically conductive ferrimagnetic material or an electrically conductive ferromagnetic material.

[0045] Additionally, the liquid conduit may include a second susceptor material. The first susceptor material can be optimized for heat loss and therefore heating efficiency, and the second susceptor material can be used as a temperature marker. For this purpose, the second susceptor material preferably includes one of a ferrimagnetic material and a ferromagnetic material. In particular, the second susceptor material can be selected to have a Curie temperature corresponding to a predetermined heating temperature. At that Curie temperature, the magnetic properties of the second susceptor material change from ferromagnetic or ferrimagnetic to paramagnetic, accompanied by a temporary change in its electrical resistance. Therefore, by monitoring the corresponding change in the current absorbed by the induction source, it is possible to detect when the second susceptor material reaches its Curie temperature, and therefore the predetermined heating temperature. The first susceptor material is preferably different from the second susceptor material. The second susceptor material preferably has a Curie temperature lower than 500 degrees Celsius. In particular, the second susceptor material may have a Curie temperature below 350° C., preferably below 300° C., more preferably below 250° C., even more preferably below 200° C., and most preferably below 150° C. The Curie temperature is preferably selected to be below the boiling point of the aerosol-forming liquid to be vaporized, to prevent the generation of harmful components in the aerosol.

[0046] In particular, the liquid conduit may be an inductively heatable liquid conduit made solely of one or more susceptor materials.

[0047] As an example, the liquid conduit may include a first susceptor material or multiple first filaments made of the first susceptor material. Additionally, the liquid conduit may include a second susceptor material or multiple second filaments made of the second susceptor material. Only a few second filaments are required to fully function as temperature markers. Therefore, the number of first filaments may be greater than the number of second filaments, particularly two, three, four, five, six, seven, eight, nine, or ten times greater. Preferably, the diameters of the first and second filaments are greater than twice the skin depth to induce a sufficient amount of eddy currents and thus generate a sufficient amount of thermal energy when exposed to an alternating magnetic field. Skin depth is a measure of how far electrical conduction occurs within a conductive susceptor material when inductively heated. Thus, depending on the material and frequency of the alternating magnetic field used, the first and second filaments may have a diameter of at least 0.015 millimeters, at least 0.02 millimeters, at least 0.025 millimeters, at least 0.05 millimeters, at least 0.075 millimeters, at least 0.1 millimeters, at least 0.125 millimeters, at least 0.15 millimeters, at least 0.2 millimeters, at least 0.3 millimeters, or at least 0.4 millimeters. The second filaments may be randomly distributed throughout the liquid conduit. Advantageously, the random distribution requires only minor effort during the manufacture of the liquid conduit.

[0048] The plurality of first filaments and optional plurality of second filaments may be used in any of the liquid conduit configurations described above, such as a bundle of filaments including at least one parallel bundle portion, a bundle of filaments including two immersed sections and an intermediate portion, or a liquid conduit including two filament arrays that partially cross each other to form at least one grid portion and at least one non-grid portion.

[0049] If the liquid conduit is inductively heatable, the filament may be disposed off-center with respect to the geometric central axis of the aerosol-generating article. Thus, the liquid conduit may be disposed off-center with respect to the axis of symmetry of the alternating magnetic field generated by the inductively heated aerosol generating device, into which the aerosol-generating article may be inserted to heat the liquid conduit. Advantageously, the off-center, i.e., asymmetric, arrangement places the liquid conduit in a region of the alternating magnetic field having a higher magnetic field density than a symmetric arrangement. As a result, heating efficiency is enhanced.

[0050] The aerosol-generating article may be a single-use aerosol-generating article or a multi-use aerosol-generating article. In the latter case, the aerosol-generating article may be refillable, i.e., the main reservoir may be refillable with the aerosol-forming liquid. In any configuration, the aerosol-generating article may further comprise an aerosol-forming liquid contained in at least one of the main reservoir and the capillary buffer reservoir.

[0051] The term "aerosol-forming liquid" as used herein refers to a liquid capable of releasing volatile compounds capable of forming an aerosol upon heating the aerosol-forming liquid. The aerosol-forming liquid is intended to be heated. The aerosol-forming liquid may include both solid and liquid aerosol-forming materials or components. The aerosol-forming liquid may include a tobacco-containing material containing volatile tobacco flavor compounds that are released from the liquid upon heating. Alternatively, or in addition, the aerosol-forming liquid may include a non-tobacco material. The aerosol-forming liquid may further include an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol. The aerosol-forming liquid may also include other additives and ingredients (such as nicotine or flavoring agents). In particular, the aerosol-forming liquid may include water, solvents, ethanol, plant extracts, and natural or artificial flavors. The aerosol-forming liquid may be an aqueous aerosol-forming liquid or an oil-based aerosol-forming liquid.

[0052] Additionally, the article may include a mouthpiece. As used herein, the term "mouthpiece" refers to the portion of the article that is placed in the user's mouth to directly inhale the aerosol from the article. The mouthpiece preferably includes a filter. The filter may be used to filter out undesirable components of the aerosol. The filter may also include additional materials, such as flavoring materials, that are added to the aerosol.

[0053] According to the present invention there is also provided an aerosol generating system comprising an aerosol generating device according to the present invention and as described herein and an aerosol generating article, the article being configured for use with the aerosol generating device.

[0054] As used herein, the term "aerosol-generating device" is used to describe an electrically operated device capable of interacting with at least one aerosol-generating article containing at least one aerosol-forming liquid to generate an aerosol by heating the aerosol-forming liquid within the article. The aerosol-generating device is preferably a smoking device for generating an aerosol that can be directly inhaled by a user through the user's mouth. In particular, the aerosol-generating device is a handheld aerosol-generating device.

[0055] The device may comprise a receiving cavity for removably receiving at least a portion of the aerosol-generating article.

[0056] In addition, the aerosol generating device may comprise an electric heating arrangement configured to heat the aerosol-forming liquid conveyed by the liquid conduits from the buffer reservoir (and, if applicable, from the main reservoir) to regions external to the buffer reservoir and the main reservoir, in particular the above-mentioned vaporization zone.

[0057] The heating arrangement may be a resistive heating arrangement including a resistive heating element for heating the aerosol-forming liquid. The resistive heating element may be, for example, a heating wire or a heating coil. In use, the resistive heating element is disposed in thermal contact with or in thermal proximity to the liquid conduit, particularly a portion of the liquid conduit disposed within the vaporization zone of the aerosol-generating article, when the aerosol-generating article is received within the aerosol-generating device.

[0058] Alternatively, the heating arrangement may be an induction heating arrangement. That is, the aerosol-generating device may be an induction-heated aerosol-generating device. This configuration is particularly preferred when the liquid conduit of the article is induction-heatable. Induction heating may also function when the aerosol-generating article includes a (separate) susceptor element arranged in thermal contact with or in thermal proximity to a liquid conduit, particularly a portion of the liquid conduit, arranged in the vaporization zone of the aerosol-generating article. It is also possible for the aerosol-generating device itself to include a susceptor element arranged in thermal contact with or in thermal proximity to a liquid conduit, particularly a portion of the liquid conduit arranged in the vaporization zone of the aerosol-generating article, when the aerosol-generating article is received within the aerosol-generating device. In the latter configuration, i.e., when the liquid conduit itself is not induction-heatable, the susceptor element may be, for example, a susceptor sleeve or susceptor coil surrounding the liquid conduit, particularly a portion of the liquid conduit arranged in the vaporization zone of the aerosol-generating article.

[0059] An induction heating aerosol generating device, and in particular an induction heating arrangement, may include at least one induction source configured and arranged to generate an alternating magnetic field within a receiving cavity to inductively heat an aerosol-forming liquid within an aerosol-generating article when the article is received within the aerosol generating device.

[0060] To generate the alternating magnetic field, the induction source may include at least one inductor, preferably at least one induction coil disposed around the receiving cavity. If the liquid conduit is inductively heatable, the induction coil is disposed around the liquid conduit when the article is received within the receiving cavity, particularly around a portion of the liquid conduit disposed within the vaporization zone of the aerosol-generating article.

[0061] The at least one induction coil may be a helical coil or a flat, planar coil, particularly a pancake coil or a curved, planar coil. The use of a flat spiral coil allows for a compact design that is robust and inexpensive to manufacture. The use of a helical induction coil advantageously allows for the generation of a homogeneous alternating magnetic field. As used herein, "flat spiral coil" refers to a generally planar coil, with the axis of the coil's windings perpendicular to the surface on which the coil is placed. A flat spiral induction coil can have any desired shape within the plane of the coil. For example, a flat spiral coil may have a circular shape or a generally elliptical or rectangular shape. However, the term "flat spiral coil" as used herein encompasses both planar coils and flat spiral coils shaped to conform to curved surfaces. For example, the induction coil may be a "curved" planar coil disposed around a preferably cylindrical coil support (e.g., a ferrite core). Furthermore, the flat spiral coil may comprise, for example, two layers of a four-turn flat spiral coil or a single layer of a four-turn flat spiral coil. At least one induction coil may be carried within at least one of the main body or housing of the aerosol generating device.

[0062] The aerosol-generating article may be configured such that the inductively heatable liquid conduit, if present, is disposed off-center with respect to the axis of symmetry of the alternating magnetic field generated by the induction source when the article is received in the receiving cavity of the aerosol-generating device. As described above, the off-center, i.e., asymmetric, arrangement places the liquid conduit in a region of the alternating magnetic field having a higher magnetic field density compared to a symmetric arrangement. As a result, heating efficiency is enhanced.

[0063] The induction source may comprise an alternating current (AC) generator. The AC generator may be powered by a power supply of the aerosol generating device. The AC generator is operably coupled to at least one induction coil. In particular, the at least one induction coil may be an integral part of the AC generator. The AC generator is configured to generate a high frequency oscillating current that passes through the at least one induction coil to generate an alternating magnetic field. The AC current may be supplied to the at least one induction coil continuously after activation of the system, or may be supplied intermittently, for example, for each puff.

[0064] Preferably, the inductive source comprises a DC / AC converter connected to a DC power supply including an LC network, the LC network comprising a series connection of a capacitor and an inductor.

[0065] The induction source is preferably configured to generate a radio frequency magnetic field, which as referred to herein may be in the range of 500 kHz (kilohertz) to 30 MHz (megahertz), particularly 5 MHz (megahertz) to 15 MHz (megahertz), preferably 5 MHz (megahertz) to 10 MHz (megahertz).

[0066] The aerosol-generating device may further comprise a controller configured to control the operation of the heating process, preferably in a closed-loop configuration, in particular to control the heating of the aerosol-forming liquid to a predetermined operating temperature. The operating temperature used to heat the aerosol-forming liquid may be in the range of 100°C to 300°C, in particular 150°C to 250°C, for example 230°C. These temperatures are typical operating temperatures for heating but not burning the aerosol-forming substrate.

[0067] The controller may be the overall controller of the aerosol generating device or may be part of the overall controller of the aerosol generating device. The controller may comprise a microprocessor, such as a programmable microprocessor, a microcontroller, or an application specific integrated circuit chip (ASIC) or other electronic circuit capable of providing control. The controller may include further electronic components, such as at least one DC / AC inverter and / or a power amplifier, such as a class C power amplifier, a class D power amplifier, or a class E power amplifier. In particular, the inductive source may be part of the controller.

[0068] The aerosol generating device may include a power source, particularly a DC power source configured to provide a DC supply voltage and a DC supply current to the induction source. The power source is preferably a battery, such as a lithium iron phosphate battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging, i.e., the power source may be rechargeable. The power source may have a capacity that allows for storage of energy sufficient for one or more user experiences. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for approximately six minutes, or a multiple of six minutes. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of puffs, or for discontinuous activation of the induction source.

[0069] In the case of an induction heating aerosol generating device, the aerosol generating device may further comprise a magnetic flux concentrator disposed around at least a portion of the induction coil and configured to distort the alternating magnetic field of the at least one induction source toward the receiving cavity. Thus, when an item is received in the receiving cavity, the alternating magnetic field, if present, is distorted toward the inductively heatable liquid conduit. Preferably, the magnetic flux concentrator comprises a magnetic flux concentrator foil, in particular a multilayer magnetic flux concentrator foil.

[0070] Further features and advantages of the aerosol-generating system according to the invention have already been described above in relation to the aerosol-generating article according to the invention and apply equally.

[0071] The present invention is defined in the claims. However, the following provides a non-exhaustive list of non-limiting examples. Any one or more features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein. Example Ex1: An aerosol-generating article for use with an aerosol-generating device, the article comprising: a main reservoir for storing an aerosol-forming liquid; a capillary buffer reservoir in fluid communication with the main reservoir for storing an aerosol-forming liquid due to capillary action; a liquid conduit in fluid communication with at least the capillary buffer reservoir for providing aerosol-forming liquid at an interface to the exterior of the capillary buffer reservoir and the main reservoir. Example Ex2: An aerosol-generating article according to example Ex1, wherein the maximum dimension between two opposing walls defining at least a portion of the capillary buffer reservoir is in the range of 0.2 millimeters to 5 millimeters, in particular 0.5 millimeters to 3 millimeters, preferably 1 millimeter to 2.5 millimeters. Example Ex3: An aerosol-generating article according to any one of the preceding examples, wherein the capillary buffer reservoir has a total volume of at most 60 cubic millimeters, in particular at most 50 cubic millimeters, preferably at most 40 cubic millimeters, more preferably at most 30 cubic millimeters, and most preferably at most 20 cubic millimeters. Example Ex4: An aerosol-generating article according to any one of the preceding examples, wherein the capillary buffer reservoir has a total volume of at least 5 cubic millimeters, in particular at least 10 cubic millimeters, preferably at least 15 cubic millimeters. Example Ex5: An aerosol-generating article according to any one of the preceding examples, wherein the capillary buffer reservoir comprises a lamellar structure. Example Ex6: An aerosol-generating article according to example Ex5, wherein the lamellar structure comprises a plurality of lamellae, the maximum dimension between adjacent lamellae being in the range of 0.2 millimeters to 5 millimeters, in particular 0.5 millimeters to 2.5 millimeters, preferably 1 millimeter to 2 millimeters. Example Ex7: An aerosol-generating article according to any one of the preceding examples, wherein the main reservoir opens directly into the capillary buffer reservoir. Example Ex8: The aerosol-generating article of any one of the preceding examples Ex1-Ex6, wherein the main reservoir and the capillary buffer reservoir are in fluid communication with each other via at least the first liquid channel. Example Ex9: An aerosol-generating article according to example Ex8, wherein the first liquid channel is configured to redirect the flow of liquid through the article by at least 90 degrees, in particular 180 degrees. Example Ex10: An aerosol-generating article according to any one of the preceding examples, wherein the main reservoir and the capillary buffer reservoir are in fluid communication with each other via the second liquid channel. Example Ex11: An aerosol-generating article according to example Ex9 or Ex10, wherein the maximum dimension between two opposing walls defining at least a portion of at least one of the first and second fluid channels, in particular the diameter of at least one of the first and second fluid channels, is in the range of 0.2 millimeters to 5 millimeters, in particular 0.5 millimeters to 4 millimeters, preferably 1 millimeter to 3 millimeters, and most preferably 2 millimeters to 3 millimeters. Example Ex12: An aerosol-generating article according to any one of the preceding examples, wherein the capillary buffer reservoir is downstream of the main reservoir with respect to the flow of liquid through the article. Example Ex13: An aerosol-generating article according to any one of the preceding examples, wherein, with respect to the flow of liquid through the article, the liquid conduit is downstream of the capillary buffer reservoir. Example Ex14: An aerosol-generating article according to any one of the preceding examples, wherein at least a portion of the fluid conduit is disposed at or within a downstream portion of the capillary buffer reservoir, with respect to the flow of liquid through the article. Example Ex15: An aerosol-generating article according to any one of the preceding examples, wherein the capillary buffer reservoir is disposed adjacent to the main reservoir. Example Ex16: The aerosol-generating article of any one of the preceding examples, further comprising a partition wall defining both at least a portion of the main reservoir and at least a portion of the capillary buffer reservoir. Example Ex17: An aerosol-generating article according to any one of the preceding examples, wherein at least a portion of the main reservoir and at least a portion of the capillary buffer reservoir are integrally formed with one another. Example Ex18: An aerosol-generating article according to any one of the preceding examples, wherein the liquid conduit is in direct fluid communication with the main reservoir. Example Ex19: An aerosol-generating article according to any one of the preceding examples, further comprising a bypass channel that bypasses the main reservoir and provides direct fluid communication between the main reservoir and the fluid conduit. Example Ex20: An aerosol-generating article described in any one of the preceding examples, further comprising three intersecting fluid channels, each of the three intersecting fluid channels connected to one of the main reservoir, the capillary buffer reservoir, and the fluid conduit, to provide nodal fluid communication between each two of the main reservoir, the capillary buffer reservoir, and the fluid conduit. Example Ex21: The aerosol-generating article of any one of the preceding examples, wherein the liquid conduit passes through a wall that defines at least a portion of the capillary buffer reservoir. Example Ex22: An aerosol-generating article according to any one of the preceding examples, wherein the article comprises a vaporization zone. Example Ex23: An aerosol-generating article according to example Ex22, wherein the liquid conduit passes through or faces the vaporization zone. Example Ex24: An aerosol-generating article according to any one of the preceding examples, wherein the liquid conduit comprises a core element, in particular a bundle of filaments, preferably a bundle of non-stranded filaments, or a mesh. Example Ex25: An aerosol-generating article according to any one of the preceding examples, wherein the liquid conduit is inductively heatable. Example Ex26: The aerosol-generating article of any one of the preceding examples, wherein the liquid conduit comprises a liquid-transporting susceptor assembly. Example Ex27: An aerosol-generating article according to any one of the preceding examples, further comprising an aerosol-forming liquid contained within at least one of the main reservoir and the capillary buffer reservoir. Example Ex28: An aerosol-generating system comprising an aerosol-generating device and an aerosol-generating article according to any one of the preceding examples for use with the device.

[0072] The embodiments will now be further described with reference to the following figures: [Brief explanation of the drawings]

[0073] [Figure 1] 1 illustrates schematically a first embodiment of an aerosol-generating article according to the present invention; [Figure 2] 2 shows a cross section through the aerosol-generating article according to FIG. 1 along line AA. [Figure 3] 2 shows a cross section through the aerosol-generating article according to FIG. 1 along line BB. [Figure 4] 2 illustrates schematically an exemplary embodiment of an aerosol generation system according to the invention, comprising an article according to FIG. 1 and an aerosol generation device for use with said article; [Figure 5] 1 shows an aerosol-generating article similar to that shown in FIG. 1, but without a partition wall. [Figure 6] 2 shows the aerosol-generating article according to FIG. 1 in a substantially horizontal position. [Figure 7] 2 shows the aerosol-generating article according to FIG. 1 in an upside-down position. [Figure 8] 1 illustrates schematically a second embodiment of an aerosol-generating article according to the present invention. [Figure 9] 1 illustrates schematically a third embodiment of an aerosol-generating article according to the present invention. [Figure 10] 10 shows the aerosol-generating article according to FIG. 9 in an upside-down position. [Figure 11] 1 illustrates schematically a fourth embodiment of an aerosol-generating article according to the present invention. [Figure 12] 12 shows a cross section through the aerosol-generating article according to FIG. 11 along line CC. DETAILED DESCRIPTION OF THE INVENTION

[0074] FIG. 1 schematically illustrates an aerosol-generating article 40 according to a first embodiment of the present invention. As will be described in more detail below with respect to FIG. 4, the aerosol-generating article 40 is configured to be used with an induction heating aerosol generator to vaporize an aerosol-forming liquid 50 provided by the aerosol-generating article 40. The article 40 comprises a substantially cylindrical article housing made of a liquid-impermeable rigid material, such as PP (polypropylene). The article housing comprises a cylindrical reservoir body 42, a bottom end cap 43 at one end of the reservoir body 42, and a top end cap 44 at the opposite end of the reservoir body 42. The article further comprises a partition wall 41 that divides the interior cavity of the reservoir body 42 into a first compartment and a second compartment. The first compartment and the second compartment are disposed adjacent to each other laterally along the longitudinal axis of the reservoir body 42. The first compartment serves as a main reservoir 51 for storing the aerosol-forming liquid 50. Within the second compartment, article 40 includes a substantially disk-shaped bushing 45 approximately halfway along the length of reservoir body 42. Bushing 45 separates the interior cavity of the second compartment into two portions: a vaporization cavity 53 and a capillary buffer reservoir 52 for storing aerosol-forming liquid due to capillary action, as will be described in greater detail below. Through a recess in bottom end cap 43, capillary buffer reservoir 52 is in fluid communication with main reservoir 51. The recess in bottom end cap 43 is shaped so that main reservoir 51 opens directly into capillary buffer reservoir 52, allowing aerosol-forming liquid 50 to flow freely from main reservoir 51 into capillary buffer reservoir 52. To facilitate liquid flow around the free end of partition wall 41 facing bottom end cap 43, the free end of partition wall 41 includes a rounded edge. In particular, rounded edges facilitate air seeping into the reservoir as it flows around the edge of the divider. In contrast, sharp edges can trap air bubbles due to pinning of the contact line.

[0075] Generally, the aerosol-generating article 40 may be a single-use aerosol-generating article or a multi-use aerosol-generating article. In the latter case, the aerosol-generating article 40 may be refillable, i.e., the main reservoir 51 may be refillable with aerosol-forming liquid 50 after it has been depleted.

[0076] The article 40 further comprises a liquid conduit 70 in fluid communication with the capillary buffer reservoir 52 for transporting the aerosol-forming liquid 50 from the capillary buffer reservoir 52 into the vaporization cavity 53. Further details of the liquid conduit 70 are illustrated in FIGS. 2 and 3, which show cross sections through the aerosol-generating article according to FIG. 1 along lines AA and BB, respectively. In this embodiment, the liquid conduit 70 is realized as a non-stranded filament bundle comprising multiple filaments 71, 72 arranged parallel to one another. Due to the arrangement of the filaments 71, 72 in the filament bundle and due to the small diameters of the filaments 71, 72, the liquid conduit 70 comprises narrow channels formed between the filaments 71 and 72. These channels provide capillary action along the extended length of the liquid conduit 70, thus enabling the transport of the aerosol-forming liquid 50 from the capillary buffer reservoir 52 to the vaporization cavity 53.

[0077] In addition to its liquid transport properties, the liquid conduit 70 is also configured for induction heating. To that end, the liquid conduit 70 includes at least a plurality of first filaments 71 comprising a first susceptor material optimized for heat generation. The liquid conduit 70 may also include a plurality of second filaments 72 comprising a second susceptor material that functions as a temperature marker, as described above. Due to the sensitive nature of the filament material, the liquid conduit 70 has the ability to be inductively heated in an alternating magnetic field and, therefore, vaporize an aerosol-forming liquid in thermal contact with the filaments 71, 72. Thus, the liquid conduit 70 is capable of performing the dual functions of transporting and heating the aerosol-forming liquid. For this reason, the liquid conduit is also referred to as a liquid transport-susceptor assembly.

[0078] As can be seen in FIG. 1 , liquid conduit 70 passes through an opening in bushing 45 such that a first portion of liquid conduit 70 is disposed within buffer reservoir 52 and a second portion is disposed within vaporization cavity 53. The opening through bushing 45 serves not only as a feedthrough for the liquid conduit but also to bundle filaments 71, 72, i.e., to keep filaments 71, 72 together. Additionally, the opening serves to fix the position of liquid conduit 70 relative to the article housing. As can be further seen in FIGS. 2 and 3 , the filament bundle of liquid conduit 70 has a substantially circular cross-section, which is particularly simple to manufacture.

[0079] A first portion of the liquid conduit 70 is disposed within the buffer reservoir 52 and is thus submerged in the aerosol-forming liquid 50, thereby acting as an immersion section 75 for transporting the aerosol-forming liquid 50 from the buffer reservoir 52 to the second portion of the liquid conduit 70. In the vaporization cavity 53, the second portion acts at least in part as a heating section 76 for vaporizing the aerosol-forming liquid 50 when exposed to an alternating magnetic field to inductively heat the filaments 71, 72. This is described in more detail below with respect to FIG.

[0080] As can be further seen in FIG. 1 , the article 40 includes at least one air inlet 46 through the reservoir body 42 and into the vaporization cavity 53, thereby allowing air to enter the vaporization cavity 53. The air inlet 46 can be configured to provide airflow to or around the heated section 76 of the liquid conduit 70. The air inlet 46 may be a hole through the reservoir body 42. Similarly, the air inlet 46 may be a nozzle configured to direct the airflow to a specific target location in the liquid conduit 70. Additionally, the article 40 includes a tapered mouthpiece 47 attached to the top end cap 44 and configured to be taken into a user's mouth for puffing. The mouthpiece 47 further includes a filter (not shown) and an air outlet 48. The mouthpiece 47 is in fluid communication with the vaporization cavity 45 through an outlet 49 in the top end cap 44. As such, when a user puffs on the mouthpiece 47, air is drawn through the air inlet 46 and into the vaporization cavity 53. From there, air passes through opening 49 into mouthpiece 47, and further through filter 55 and air outlet 48 into the user's mouth. In vaporization cavity 53, vaporized aerosol-forming liquid from heated section 76 of liquid conduit 70 is exposed to air passing through article 40 to form an aerosol, which can then be drawn through mouthpiece 47.

[0081] FIG. 4 schematically illustrates an aerosol generation system 80 according to an exemplary embodiment of the present invention. The system 80 includes the aerosol-generating article 40 shown in FIGS. 1-3 and an electrically operated aerosol generation device 60 capable of interacting with the article 40 to generate an aerosol. To this end, the aerosol generation device 60 includes a receiving cavity 62 formed within a device housing 61 at a proximal end of the device 60. The receiving cavity 62 is configured to removably receive at least a portion of the aerosol-generating article 40. In particular, the aerosol generation device is configured to inductively heat the heating section 76 of the liquid conduit 70 to vaporize the aerosol-forming liquid 50 transported from the capillary buffer reservoir 52 to the heating section 76 within the vaporization cavity 53 via the immersion section 75. To this end, the aerosol generation device 60 includes an induction source including an induction coil 32. In this embodiment, the induction coil 32 is a single helical coil arranged and configured to generate a substantially homogeneous alternating magnetic field within the receiving cavity 62. As can be seen in FIG. 4 , the induction coil 32 is disposed around the proximal end portion of the receiving cavity 62 so as to only surround the heated section 76 of the liquid conduit 70 when the aerosol-generating article 40 is received within the receiving cavity 62. Thus, during use of the device 60, the induction coil 32 generates an alternating magnetic field that only penetrates the heated section 76 of the liquid conduit 70 within the vaporization cavity 53 of the article 40. In contrast, due to localized heating, the immersion section 75 of the liquid conduit 70 remains below the vaporization temperature. Thus, boiling of the aerosol-forming liquid 50 within the capillary buffer reservoir 52 and the main reservoir 51 is prevented. Thus, during use, the liquid conduit 70 includes a temperature profile along its length having hot and cold sections. More specifically, the temperature profile shows a temperature increase from below the vaporization temperature T_vap of the aerosol-forming liquid 50 in the submerged section 75 to above the respective vaporization temperature in the heated section 76 .

[0082] The actual temperature profile formed during use of the susceptor assembly 10 depends on the thermal conductivity and the length of the liquid conduit 70. Therefore, to have a sufficient temperature gradient between the submerged section 75 and the heated section 76, the liquid conduit 70 requires a certain overall length. For this embodiment, the overall length of the liquid conduit 70 may be in the range of 5 to 50 millimeters, particularly 10 to 40 millimeters, preferably 10 to 30 millimeters, and more preferably 10 to 20 millimeters.

[0083] The liquid conduit 70 is disposed off-center relative to the geometric central axis of the aerosol-generating article 40. Thus, the liquid conduit 70 is disposed off-center with respect to the axis of symmetry of the alternating magnetic field generated by the induction coil 32 when the article 40 is received within the cavity 62 of the apparatus 60. Advantageously, the off-center positioning places the liquid conduit 70 in a region of the alternating magnetic field having a higher magnetic field density compared to a symmetrical central positioning. As a result, heating efficiency is enhanced.

[0084] The aerosol generating device 60 further includes a controller 64 for controlling the operation of the aerosol generating system 80, specifically for controlling the heating operation. Furthermore, the aerosol generating device 60 includes a power supply 63 for providing power for generating the alternating magnetic field. The power supply 63 is preferably a battery, such as a lithium iron phosphate battery. The power supply 63 may have a capacity that allows for sufficient energy storage for one or more user experiences. Both the controller 64 and the power supply 63 are disposed in a distal portion of the aerosol generating device 60.

[0085] The function of the capillary buffer reservoir 52 will now be explained in more detail with respect to Figures 5-7.

[0086] Figure 5 shows the aerosol-generating article 40 according to Figure 1, but without the capillary buffer reservoir. Furthermore, in contrast to Figure 1, Figure 5 shows the article 40 in a substantially horizontal orientation. The different orientation causes the aerosol-forming liquid 50 within the article 40 to be redistributed in such a way that (depending on the fluid level) the liquid conduit 70 is no longer in contact with the aerosol-forming liquid 50. As a result, if the article is used in this orientation for a certain period of time, the delivery of aerosol-forming liquid to the evaporation zone 53 will be interrupted, which will cause a rapid decline in aerosol formation or even failure.

[0087] The purpose of the buffer reservoir 52 is to remedy this. Essentially, the buffer reservoir 52 provides a small-volume reservoir in fluid communication with the main reservoir 51 and the liquid conduit 70, configured to confine a specific amount of aerosol-forming liquid due to capillary action, regardless of the article's orientation. To this end, at least one dimension of the capillary buffer reservoir 52 is selected to be on the order of an effective capillary length, which is typically in the range of a few millimeters for most liquids. In this embodiment, the capillary action of the buffer reservoir 52 is caused by the fact that the maximum distance D between opposing portions of the partition wall 41 and the inner surface of the reservoir body 42, as shown in FIGS. 3 and 6, is in the range of only a few millimeters. For example, the maximum distance D may be in the range of 1 millimeter to 5 millimeters. This allows the capillary effect to dominate over gravity within the capillary buffer reservoir 52. As a result, after the aerosol-forming liquid 50 has filled into the buffer reservoir 52, the aerosol-forming liquid 50 is prevented from flowing back into the main reservoir 51 when the article orientation is changed, for example, when the article 40 is rotated from a substantially upright position as shown in FIG. 1 to a substantially horizontal position as shown in FIG. 6, or even to an upside-down position as shown in FIG. 7. Thus, regardless of the article orientation, similar to the buffer reservoir of a fountain pen, the buffer reservoir 40 reliably confines the liquid aerosol formation due to capillary action in its small volume. Furthermore, capillary action along the liquid conduit is still sufficient to transport the trapped liquid from the capillary buffer reservoir 52 to the vaporization zone.

[0088] The volume of the buffer reservoir is selected to provide sufficient liquid available for several puffs, regardless of the orientation of the article. Thus, the total volume of the capillary buffer reservoir 52 may be at least 5 cubic millimeters, particularly at least 10 cubic millimeters, and preferably at least 15 cubic millimeters.

[0089] FIG. 8 schematically illustrates a second exemplary embodiment of an aerosol-generating article 140 according to the present invention. Generally, the aerosol-generating article 140 according to FIG. 8 is very similar to the aerosol-generating article 40 shown in FIG. 1 . Accordingly, identical or similar features are designated by the same reference numerals, but incremented by 100. In contrast to the first embodiment shown in FIG. 1 , the main reservoir 151 does not extend directly into the capillary buffer reservoir 152. Instead, the main reservoir 151 and the capillary buffer reservoir 152 are in fluid communication with each other via a liquid channel 154. The first liquid channel is formed in the bottom end cap 143 and is configured to redirect the liquid flow 180 degrees from the main reservoir 151 to the capillary buffer reservoir 152. This configuration can retard unexpected reflux of the aerosol-forming liquid from the capillary buffer reservoir 152 to the main reservoir 154. In addition to the first liquid channel 154, the main reservoir 151 and the capillary buffer reservoir 152 may also be in fluid communication with one another through the partition wall 141 via a second liquid channel 155. The second channel 155 may facilitate, and in particular facilitate, the refilling of the capillary buffer reservoir 152 from the main reservoir 151 during or after depletion of the aerosol-forming liquid in the capillary buffer reservoir via the liquid conduit 170, which is a use of the system.

[0090] 9 and 10 schematically illustrate a third exemplary embodiment of an aerosol-generating article 240 according to the present invention. Generally, the aerosol-generating article 240 according to FIGS. 9 and 10 is similar to the aerosol-generating article 40 shown in FIG. 1. Accordingly, identical or similar features are designated by the same reference numerals, but incremented by 200. In contrast to the article 40 shown in FIG. 1, the article 240 according to FIGS. 9 and 10 comprises a liquid conduit 270, a buffer reservoir 252, and a vaporization zone 253, which are arranged symmetrically with respect to the geometric central axis of the article 40. The vaporization cavity 253 is formed by a cylindrical partition wall 241 coaxially arranged within the cylindrical reservoir body 242. A substantially hollow cylindrical main reservoir 251 is formed between the cylindrical reservoir body 242 and the cylindrical partition wall 241. At its bottom, the vaporization cavity 253 is closed by a disk-shaped bushing 245. Similarly, cylindrical reservoir body 242 is closed by bottom end cap 243, which includes a recess similar to bottom end cap 43 of article 40 shown in FIG. 1 . Thus, capillary buffer reservoir 252 is formed between the inner surface of bottom end cap 243 on one side and the end face of cylindrical partition wall 241 and disk-shaped bushing 245 on the other side. Distance D between the inner surface of bottom end cap 243 and the end face of cylindrical partition wall 241 and disk-shaped bushing 245 is selected to be the effective capillary length, e.g., in the range of 1 to 5 millimeters. Therefore, after being filled with aerosol-forming liquid, buffer reservoir 252 traps a certain amount of aerosol-forming liquid due to capillary action, even when article 240 is rotated, for example, from a substantially upright position as shown in FIG. 9 to an upside-down position as shown in FIG. 10 . Thus, the submerged section 275 of the liquid conduit 270 is always in contact with the aerosol-forming liquid, regardless of the position of the article. The volume of the capillary buffer reservoir 252 is selected so that the amount of aerosol-forming liquid that can be contained is sufficient for at least several puffs.

[0091] 11 and 12 schematically illustrate a fourth exemplary embodiment of an aerosol-generating article 240 according to the present invention. Generally, the aerosol-generating article 340 according to FIGS. 11 and 12 is similar to the aerosol-generating article 40 shown in FIG. 1. Accordingly, identical or similar features are designated by the same reference numerals, but incremented by 300. In contrast to the article 40 shown in FIG. 1, the article 340 according to FIGS. 11 and 12 further comprises a plurality of lamellae 358 in the partition wall 341. The plurality of lamellae 358 advantageously increases the inner surface of the buffer reservoir 352 and, therefore, its capillary action. Essentially, the lamella structure acts like the lamella structure of a fountain pen. Currently, the distance between adjacent lamellae may be in the range of 1 to 2 millimeters.

[0092] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like should be understood in all instances to be modified by the term "about." Also, all ranges include the disclosed maximum and minimum points, and any intermediate ranges therebetween, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 5%. Within this context, the number A may be considered to include values ​​that are within the typical standard error for measurement of the property that the number A modifies. In some cases, such as when used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and any intermediate ranges therebetween, which may or may not be specifically recited herein.

Claims

1. 1. An aerosol-generating article for use with an aerosol-generating device, said article comprising: a main reservoir for storing an aerosol-forming liquid; a capillary buffer reservoir in fluid communication with the main reservoir, the capillary buffer reservoir storing aerosol-forming liquid due to capillary action; a liquid conduit in fluid communication with at least the capillary buffer reservoir for providing an aerosol-forming liquid to the capillary buffer reservoir and to an exterior of the main reservoir, the liquid conduit including a bundle of filaments, the bundle of filaments including a plurality of first filaments including or made from a first susceptor material; An aerosol-generating article, wherein the buffer reservoir does not include any capillary or liquid-retaining material.

2. 2. The aerosol-generating article of claim 1, wherein the maximum dimension between two opposing walls defining at least a portion of the capillary buffer reservoir is in the range of 0.2 millimeters to 5 millimeters.

3. 3. The aerosol-generating article of claim 1, wherein the capillary buffer reservoir has a total volume of up to 60 cubic millimeters.

4. 4. An aerosol-generating article according to any one of claims 1 to 3, wherein the capillary buffer reservoir comprises a lamellar structure.

5. 5. An aerosol-generating article according to any one of claims 1 to 4, wherein the main reservoir opens directly into the capillary buffer reservoir, or the main reservoir and the capillary buffer reservoir are in fluid communication with each other via at least a first liquid channel.

6. 6. The aerosol-generating article of claim 5, wherein the first liquid channel is configured to redirect the flow of liquid through the article by at least 90 degrees.

7. 7. An aerosol-generating article according to any one of claims 1 to 6, wherein, with respect to the flow of liquid through the article, the capillary buffer reservoir is downstream of the main reservoir and the liquid conduit is downstream of the capillary buffer reservoir.

8. 8. An aerosol-generating article according to any one of claims 1 to 7, wherein, with respect to the flow of liquid through the article, at least a portion of the liquid conduit is disposed at or within a downstream portion of the capillary buffer reservoir.

9. 9. An aerosol-generating article according to any one of claims 1 to 8, wherein the capillary buffer reservoir is disposed adjacent to the main reservoir.

10. 10. An aerosol-generating article according to any one of claims 1 to 9, further comprising a partition wall defining both at least a portion of the main reservoir and at least a portion of the capillary buffer reservoir.

11. An aerosol-generating article according to any preceding claim, wherein at least a portion of the main reservoir and at least a portion of the capillary buffer reservoir are integrally formed with one another.

12. 12. An aerosol-generating article according to any preceding claim, wherein the article comprises a vaporization zone and the liquid conduit passes through or faces the vaporization zone.

13. 13. The aerosol-generating article of claim 12, wherein the main reservoir, the buffer reservoir, and the vaporization zone are fluidly connected in series.

14. An aerosol generating system comprising an aerosol generating device and an aerosol-generating article according to any one of claims 1 to 13 for use with said device.

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