RU2839411C2 - Aerosol-generating device for generating inhaled aerosol from aerosol-forming liquid - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: present invention relates to an aerosol-generating device for generating an aerosol from an aerosol-forming liquid. Aerosol-generating device comprises a liquid reservoir for storing an aerosol-forming liquid, and means for capillary transfer of liquid for transfer of liquid forming aerosol, from reservoir for liquid through opening of reservoir into section of evaporation of means for transfer of liquid from outside of reservoir. Aerosol generating device additionally contains an air branch pipe for passing the air flow through the evaporation section. Liquid reservoir is a volume compensating reservoir which is configured to counteract the capillary absorption of the liquid capillary transfer agent. Air branch pipe contains a part in the form of a pusher containing an element generating an air jet, and an expansion zone located further downstream of the element generating an air jet. Air jet generating element is configured and adapted to generate an air jet in the air flow passing through the air nozzle, which leads to a drop in the static air pressure near the evaporation section.

EFFECT: improved control of liquid flow from reservoir through means for capillary transfer of liquid into evaporation section.

15 cl, 16 dwg

Description

The present invention relates to an aerosol generating device for generating an inhalable aerosol from an aerosol forming liquid which is capable of releasing volatile compounds when heated. The present invention also relates to an aerosol generating article, an aerosol generating device and an aerosol generating system comprising such an aerosol generating device.

Devices for generating inhalable aerosols from aerosol-forming liquids are generally known from the prior art. For example, such devices may comprise a reservoir for storing an aerosol-forming liquid and a means for capillary liquid transfer for transferring the liquid from the reservoir to an evaporation section of the liquid transfer means outside the reservoir. There, the liquid can be evaporated by heating the evaporation section. The evaporated liquid is exposed to air passing through the evaporation section in such a way that an aerosol is formed, which can then be drawn out, for example, through a mouthpiece. Typically, the air flow is caused by the user's puff.

The use of a liquid capillary transport means to draw a liquid that forms an aerosol from a reservoir into an evaporation section of a liquid capillary transport means outside the reservoir is associated with problems inherent in the processes that govern the physics of capillary action. In particular, this concerns the uncontrolled absorption of the liquid capillary transport means, which can cause undesirable leakage problems and changes in the amount of liquid available in the evaporation section. The latter, in turn, can lead to undesirable changes in the amount of aerosol generated by heating the liquid in the evaporation section.

Therefore, it would be desirable to have an aerosol generating device comprising a liquid reservoir and a means for capillary liquid transfer with the advantages of the solutions of the prior art while eliminating their disadvantages. In particular, it would be desirable to have an aerosol generating device comprising a liquid reservoir and a means for capillary liquid transfer that provide improved control of the liquid flow from the reservoir through the means for capillary liquid transfer into the evaporation section.

According to the present invention, an aerosol generating device is provided for generating an aerosol from an aerosol-forming liquid. The aerosol generating device comprises a liquid reservoir for storing an aerosol-forming liquid, and a means for capillary liquid transfer for transferring the aerosol-forming liquid from the liquid reservoir through the reservoir opening into the evaporation section of the liquid transfer means outside the reservoir. The aerosol generating device further comprises an air pipe for passing an air flow through the evaporation section. The liquid reservoir is a volume-compensating liquid reservoir that is designed to counteract capillary absorption of the liquid capillary transfer means. The air pipe comprises a part in the form of a pusher containing an element generating an air jet, and an expansion zone located further along the flow from the element generating the air jet. The air jet generating element is configured and adapted to generate an air jet in an air flow passing through the air pipe, which results in a drop in static air pressure near the evaporation section.

According to the present invention, it has been found that uncontrolled absorption of the means for capillary liquid transfer can be prevented by using a volume-compensating liquid reservoir that counteracts the absorption of the means for capillary liquid transfer. For this purpose, the volume-compensating liquid reservoir is designed to provide a restoring force that inhibits capillary absorption, i.e. counteracts the capillary suction and static pressure of the liquid that would otherwise cause leakage. Details and specific examples of the volume-compensating liquid reservoir will be further described below. In order to provide an alternative mechanism for transporting liquid other than uncontrolled absorption, the present invention proposes to cause an appropriate drop in static pressure near the evaporation section, which counteracts the restoring force of the volume-compensating liquid reservoir and which thus leads to the liquid being drawn from the reservoir through the means for capillary liquid transfer into the evaporation section. According to the present invention, the pressure drop is caused by an air jet generated by a part in the form of an ejector of an air pipe, including an air jet generating element, in which the Bernoulli principle is applied. Details and specific examples of the air jet generating element will be further described below. The physical mechanism behind the static pressure drop, as seen under a microscope, is as follows. Fast-moving air particles in an air jet expelled into the open atmosphere located downstream of the air jet generating element collide with air particles that are randomly and slowly moving around. The collision pushes the "stationary" air particles even further, which leads to a local pressure drop, which in turn leads to more air particles from the surrounding environment being drawn into the air jet. The air jet thus leaves behind a partial vacuum, which is felt as a pressure drop within the liquid transport means, causing a pressure gradient along the liquid capillary transport means, which draws the liquid from the reservoir through the liquid capillary transport means into the evaporation section. The air jet further causes the aerosol-forming liquid evaporated in the evaporation section to be drawn into the air stream and subsequently mixed with air in the expansion zone located downstream of the air jet generating element, to thereby form an aerosol.

Together, the volume compensating liquid reservoir and the air jet generating element form a well-balanced system which, on the one hand, suppresses uncontrolled absorption and thus provides protection against leaks, in particular when the system is not in use. On the other hand, this system allows better control of the liquid flow rate through the liquid capillary transfer means by using the Bernoulli principle in the air flow passing through the air nozzle during use. Control of the liquid flow rate through the liquid capillary transfer means, preferably in combination with control of the temperature of the heating process, in turn allows better control of the aerosol generation rate.

Preferably, the pressure drop caused by the air flow and thus the liquid flow through the means for capillary liquid transfer are/can be initiated by the user's inhalation. For this purpose, the aerosol generating device is designed in such a way that the air flow passing through the air pipe is initiated by the user's inhalation, i.e. by the user taking a puff at the outlet of the air pipe, such as a mouthpiece, located downstream of the ejector portion. The user's puff initiates a low pressure in the outlet, which in turn causes air to enter the air pipe at the inlet of the air pipe located upstream of the ejector portion. In particular, by changing the intensity of the user's inhalation, the flow rate of the liquid from the reservoir through the means for capillary liquid transfer into the evaporation section can be controlled by the user, in particular. Conversely, when the user is not puffing, and therefore when no air is flowing through the air inlet, there is no pressure drop near the evaporation section. In this situation, the restoring force provided by the volume-compensating liquid reservoir overcomes the capillary action and thus prevents capillary absorption.

In general, the restoring force used to counteract capillary absorption can be implemented in different ways. For example, the volume-compensating liquid reservoir can comprise a flexible bag for storing an aerosol-forming liquid and a low-pressure chamber hermetically sealing the flexible bag, wherein the interior of the flexible bag is in fluid communication with the means for capillary liquid transfer. That is, like the pleura of the pleural cavity that surrounds each lung in the human body, the flexible bag is sealed in the surrounding chamber, wherein the internal pressure in the sealed space between the flexible bag and the surrounding chamber is lower than the ambient pressure, in particular, atmospheric pressure. Thus, the low pressure counteracts the capillary suction of the liquid transfer means that is in fluid communication with the interior of the flexible bag. Accordingly, in the context of the present document, the term "low pressure" refers to a pressure that is lower than the ambient pressure, in particular, atmospheric pressure.

In particular, the pressure inside the low-pressure chamber acting on the outside of the flexible bag is preferably lower than the ambient pressure, in particular the atmospheric pressure, minus the sum of the static pressure of the liquid and the capillary pressure at the upstream end of the reservoir opening (or at the upstream end of the liquid capillary transfer means, where the liquid capillary transfer means has a changing capillary cross-section in the direction of the fluid flow through the liquid transfer means, see below). This advantageously prevents liquid from leaking out of the reservoir when the aerosol generating device is not in use. When a pressure drop exceeding the sum of the static pressure of the liquid and the capillary pressure is generated outside near the evaporation section, as described above, the pressure inside the low-pressure chamber exceeds the downstream pressure. As a consequence, a pressure gradient is generated in the downstream direction along the liquid capillary transfer means, which draws liquid from the flexible bag through the liquid capillary transfer means into the evaporation section. After the external pressure drop has disappeared, the liquid remaining inside the liquid capillary transfer means is forced back into the flexible bag by the ambient pressure, in particular atmospheric pressure, until the system finally reaches a state of equilibrium. Due to the extraction of liquid, the flexible bag is compressed by a volume equal to the volume of liquid extracted from the reservoir and is eventually evaporated in the evaporation section.

Preferably, the flexible bag is made of plastic, such as polyvinyl chloride, polypropylene, polyethylene, ethylene vinyl acetate. In the context of this document, the term "flexible bag" refers to a bag whose walls cannot resist deformation. That is, the walls of the flexible bag are not rigid. Since the flexible bag is designed to store an aerosol-forming liquid, the flexible bag is impermeable to the fluid, that is, the walls of the flexible bag are impermeable to the fluid.

In contrast, the low-pressure chamber preferably has rigid walls. That is, the low-pressure chamber is preferably a chamber with rigid walls. As a result, the low-pressure chamber can maintain a low pressure inside and resist deformation both from the inside and from the outside. Like the flexible bag, the walls of the low-pressure chamber are impermeable to the fluid. For example, the walls of the low-pressure chamber can be made of plastic, in particular silicone, PP (polypropylene), PE (polyethylene) or PET (polyethylene terephthalate).

According to another example, the volume compensating liquid reservoir may comprise a rigid-walled chamber comprising at least one vent. The vent may have a size that allows the aerosol-forming liquid in the liquid reservoir to form a meniscus facing the interior of the liquid reservoir. That is, the vent is preferably sized within the capillary range. As a result, the meniscus formed at the air-liquid interface can resist the surface tension that moves the liquid through the means for capillary liquid transport. This concept is based on the consideration that a completely closed rigid reservoir provides the greatest resistance to volume change and can resist capillary absorption to the greatest extent. In contrast, a reservoir communicating with the atmosphere has the least resistance to volume change and, therefore, can hardly prevent capillary absorption. Meanwhile, when the reservoir comprises an opening whose size is limited by the capillary range, the resistance to volume change is inversely proportional to the size of the opening. Thus, the liquid tension on the vent wall creates a meniscus that deforms much like a convex membrane until the liquid tension in the tank opening is balanced. This mechanism depends solely on the geometric parameters. Therefore, proper selection of the tank opening and vent geometry can ensure that the liquid is contained within the tank opening and vent, thereby preventing leaks.

For example, the ventilation opening may have a size in the range of 0.05 millimeters to 3 millimeters, in particular from 0.05 millimeters to 1.5 millimeters, preferably from 0.05 millimeters to 1 millimeter, or from 0.1 millimeters to 0.7 millimeters, or from 0.2 millimeters to 0.6 millimeters, or from 0.3 millimeters to 0.6 millimeters, such as 0.5 millimeters.

Preferably, the cross-sectional area of the vent opening is smaller than the maximum cross-sectional area of the reservoir opening. This advantageously ensures a smooth flow of liquid.

Instead of simply relying on the elastic properties of the meniscus formed by the liquid in the vent hole, the hole can be closed by an elastic partition, which can be deformed under a pressure load. This makes it possible to make the meniscus more rigid by imparting elasticity, which is a source of restoring force restraining capillary absorption. The use of an elastic partition can also make it possible to increase the size of the vent hole beyond the capillary ranges. That is, the elastic partition can form an element in the form of a wall of the liquid reservoir. Therefore, according to another example, the volume-compensating liquid reservoir can comprise at least one elastic partition forming an element in the form of a wall of the liquid reservoir. Preferably, the element in the form of a wall of the liquid reservoir formed by the elastic partition is an external element in the form of a wall of the liquid reservoir, which is exposed to the interior of the liquid reservoir on its inner side and to the pressure of the environment, in particular the atmospheric pressure, on its outer side. Preferably, any other wall element of the liquid reservoir, in addition to the elastic partition, is a rigid wall element.

The elastic partition may have a Young's modulus (modulus of elasticity under tension) in the range of 1 MPa (megapascals) to 100 MPa (megapascals), in particular 2 MPa (megapascals) to 50 MPa (megapascals), preferably 2 MPa (megapascals) to 20 MPa (megapascals).

For example, the elastic forming partition can be made of rubber, latex, silicone, chloroprene, polyisoprene, nitrile or ethylene propylene.

As mentioned above, the volume compensating liquid reservoir comprises a reservoir opening with which the means for capillary transfer of liquid is in fluid communication. In the context of the present document, the term "reservoir opening" essentially denotes an outlet opening of the liquid reservoir. The reservoir opening, in particular the size of the reservoir opening, can be designed in such a way that the liquid forming the aerosol can form a meniscus inside the reservoir opening. In particular, the reservoir opening, in particular the size of the reservoir opening, can be designed in such a way that the location of the meniscus can move freely coaxially inside the reservoir opening. In this document, the term "coaxially" refers to the direction of the fluid flow through the reservoir opening. The reservoir opening can have a changing cross-section along the direction of the fluid flow through the reservoir opening in order to counteract the surface tension in the vent opening. In particular, the changing cross-section between the interior of the liquid tank and the evaporation section allows the meniscus to freely choose a new location inside the tank opening when the static balance is disturbed from the equilibrium position. At the same time, the changing cross-section between the interior of the liquid tank and the evaporation section allows minimizing the risk of liquid flooding the heated zone or air bubbles entering the liquid tank by providing a large continuous range of sizes to which the meniscus can be adapted before it reaches either end of the tank opening. Most notably, the changing cross-section between the interior of the liquid tank and the evaporation section allows the device to be stored and used in different orientations. This occurs because changes in the static pressure of the liquid due to a change in the orientation of the device are counteracted by the liquid meniscus changing its location inside the tank opening of the changing cross-section. In particular, the cross-sectional area of the vent opening is preferably smaller than the largest cross-sectional area of the tank opening. Preferably, the cross-section of the reservoir opening tapers in the upstream direction, i.e. toward the interior of the liquid reservoir. Accordingly, the smallest cross-sectional area of the reservoir opening is located on the side located upstream of the reservoir opening, while the largest cross-sectional area of the reservoir opening is located on the side located downstream of the reservoir opening. In addition to or instead of having a reservoir opening with a changing cross-section, the means for capillary liquid transfer may have a changing cross-section of the capillary along the direction of the fluid flow through the means for liquid transfer. In particular, the cross-section of the capillary of the means for capillary liquid transfer may increase along the downstream direction from the fluid flow through the means for liquid transfer to the heating section.

The liquid reservoir or at least parts of the liquid reservoir, such as the walls (wall elements) of the rigid-wall chamber or the low-pressure chamber, may comprise or be made of silicone or PP (polypropylene), PE (polyethylene) or PET (polyethylene terephthalate). It is also possible that the liquid reservoir or at least parts of the liquid reservoir comprise or are made of heat-resistant material(s), such as PEEK (polyetheretherketone), in order to ensure good thermal stability. Where induction heating is used to heat the evaporation section of the means for capillary liquid transport (see below), in particular where at least the evaporation section is inductively heated, any parts of the liquid reservoir are preferably made of material(s) that are not inductively heated, i.e. of electrically non-conductive and non-magnetic (non-ferromagnetic or non-ferromagnetic) material(s).

The aerosol generating device may be designed for single use or multiple uses. In the latter case, the liquid reservoir may be a refillable liquid reservoir that can be refilled with an aerosol-forming liquid. In another configuration, the liquid transfer means and the air pipe may be designed for multiple uses, for example, as a permanent part of the aerosol generating device, and the liquid reservoir may be designed for single use, for example, as a cartridge that is designed for use with the aerosol generating device, of which the liquid transfer means and the air pipe are a part. In any configuration, the aerosol generating device may further comprise an aerosol-forming liquid contained in the liquid reservoir.

The main function of the means for capillary liquid transfer is to transfer the aerosol-forming liquid from the liquid reservoir to the area outside the liquid reservoir. In addition, the means for capillary liquid transfer can be used as a heat source for directly heating the aerosol-forming liquid. For this purpose, the means for capillary liquid transfer can be designed with the possibility of induction heating at least in the evaporation section. Preferably, the means for capillary liquid transfer is designed with the possibility of induction heating only in the evaporation section. In this way, boiling of the aerosol-forming liquid inside the chamber-reservoir can be prevented. Advantageously, this dual function ensures material savings and a compact design of the means for capillary liquid transfer without separate means for transfer and heating. In addition, there is direct thermal contact between the heat source, i.e. the means for liquid transfer, and the aerosol-forming liquid attracted to it. Unlike the case where a separate heater is in contact with the liquid transfer means, direct contact between the liquid transfer means and a small amount of liquid predominantly provides rapid heating, i.e., rapid onset of evaporation. In this sense, the liquid transfer means can be considered as a current-collecting device for transferring liquid.

In order to ensure the possibility of induction heating, the means for capillary liquid transfer may comprise or be made of a current-collecting material at least in the evaporation section or only in the evaporation section. It is also possible that the entire means for capillary liquid transfer comprises or is made of a current-collecting material. That is, the entire means for capillary liquid transfer may be designed with the possibility of induction heating.

In the context of this document, the term "inductively heated" refers to a means for transporting a liquid, comprising a current-receiving material, which is capable of converting electromagnetic energy into heat when exposed to an alternating magnetic field. Similarly, the term "current-receiving material" refers to a material, which is capable of converting electromagnetic energy into heat when exposed to an alternating magnetic field. This may be a result of at least one of hysteresis losses or eddy currents initiated in the current-receiving material, depending on the electrical and magnetic properties of the current-receiving material. Hysteresis losses occur in ferromagnetic or ferrimagnetic current-receiving materials due to switching of magnetic domains within the material under the influence of an alternating electromagnetic field. Eddy currents are initiated in electrically conductive current-receiving materials. In the case of a conductive ferromagnetic or ferrimagnetic current collector material, heat is generated by both eddy currents and hysteresis losses.

In the case where the means for capillary liquid transfer is designed with the possibility of induction heating, the aerosol generating device may further comprise an induction source designed and arranged in such a way as to generate an alternating magnetic field at least at the location of the evaporation section. Preferably, the induction source was designed and arranged in such a way as to generate an alternating magnetic field essentially only at the location of the evaporation section, but practically or not at the location of other sections of the means for capillary liquid transfer. For example, the induction source may comprise an induction coil, which is located essentially only around the evaporation section. Accordingly, when the induction coil is driven by an alternating current, the induction coil generates an alternating magnetic field penetrating mainly into the evaporation section, thus the means for capillary liquid transfer is heated locally only in the evaporation section. In contrast, due to local heating, other sections of the means for capillary liquid transfer are not heated (if they contain current collector material at all), but remain at temperatures below the evaporation temperature. In this way, boiling of the aerosol-forming liquid in the liquid reservoir can be prevented.

As mentioned above, the induction source may comprise at least one induction coil. The at least one induction coil may be a helical coil or a flat planar coil, in particular a disk coil or a curved planar coil. The induction source may further comprise an alternating current (AC) generator. The alternating current (AC) generator may be supplied with power by a power supply unit, such as a battery. The alternating current (AC) generator is operatively connected to at least one induction coil. In particular, the at least one induction coil may be an integral part of the alternating current generator. The alternating current generator is configured to generate a high-frequency oscillating current for passing through at least one induction coil for generating an alternating magnetic field. The alternating current may be supplied to at least one induction coil continuously after activation of the system or may be supplied intermittently, for example from puff to puff. Preferably, the induction source comprises a DC to AC converter comprising an inductive-capacitive network, wherein the inductive-capacitive network comprises a series connection of a capacitor and an inductor. The DC to AC converter can be connected to a DC power supply unit. The induction source is preferably designed to generate a high-frequency magnetic field. In the context of the present document, the high-frequency magnetic field can be in the range from 500 kHz (kilohertz) to 30 MHz (megahertz), in particular from 5 MHz (megahertz) to 15 MHz (megahertz), preferably from 5 MHz (megahertz) to 10 MHz (megahertz).

The inductive source may be part of the aerosol generating device, in particular in the case where the entire aerosol generating device is part of an (independent) aerosol generating device, as will be further described below. Alternatively, the aerosol generating device (or at least most of the components of the aerosol generating device) may be part of an aerosol generating article that is adapted to be used with the aerosol generating device. Together, the aerosol generating device and the aerosol generating article form an aerosol generating system. In this configuration, the inductive source is preferably part of the aerosol generating device, but not part of the aerosol generating article. Despite this, it is possible to consider the inductive source as part of the aerosol generating device, although it is separated from other components of the aerosol generating device. That is, one part of the aerosol generating device, in particular the air nozzle, the liquid reservoir and the means for capillary transfer of liquid, is part of the aerosol generating article, while another part of the aerosol generating device, in particular the induction source, is part of the aerosol generating device. Alternatively, the induction source may not be considered part of the aerosol generating device.

In the case where the liquid transfer means is designed with the possibility of induction heating, it can comprise a first current-receiving material and a second current-receiving material (at least in the evaporation section, only in the evaporation section or in the entire liquid transfer means). While the first current-receiving material can be optimized with respect to heat loss and thus the heating efficiency, the second current-receiving material can be used as a temperature marker. For this purpose, the second current-receiving material preferably comprises one of a ferrimagnetic material or a ferromagnetic material. In particular, the second current-receiving material can be selected in such a way as to have a Curie temperature corresponding to a given heating temperature. The magnetic properties of the second current-receiving material at its Curie temperature change from ferromagnetic or ferrimagnetic to paramagnetic, which is accompanied by a temporary change in its electrical resistance. In this way, by monitoring the corresponding change in the electric current absorbed by the induction source, it is possible to detect when the second current-receiving material has reached its Curie temperature, and thus when the predetermined heating temperature has been reached. The second current-receiving material preferably has a Curie temperature that is below 500 degrees Celsius. In particular, the second current-receiving material may have a Curie temperature below 350 degrees Celsius, preferably below 300 degrees Celsius, more preferably below 250 degrees Celsius, even more preferably below 200 degrees Celsius. For example, the second current-receiving material may have a Curie temperature of approximately 220 degrees Celsius. Preferably, the Curie temperature is selected so that it is below the boiling point of the liquid forming the aerosol, which is to be evaporated, in order to prevent the generation of hazardous components in the aerosol.

Instead of heating the evaporation section itself by means of induction heating, it is also possible that the aerosol generating device comprises a heating element which is in thermal contact with the evaporation section or in thermal proximity thereto. The heating element may be a resistive heating element or an induction heating element. For example, the resistive heating element may be a wire heater, such as a heating coil, arranged around the evaporation section. The induction heating element may be a current collector element, such as a current collector plate near the evaporation section or a current collector coil arranged around the evaporation section, which is designed to be inductively heated in an alternating magnetic field generated by an induction source. As further described above with respect to the liquid transfer means configured for induction heating, the heating element, which is in thermal contact with the evaporation section or in thermal proximity to it, can be part of the (independent) aerosol generating device, together with other components of the aerosol generating device. Similarly, the heating element can be part of the aerosol generating device for use with an aerosol generating article, wherein at least some of the other components or even all of the other components of the aerosol generating device, in particular the air pipe, the liquid reservoir and the means for capillary liquid transfer, are part of the aerosol generating article.

In general, the means for capillary liquid transfer may have any shape and configuration suitable for transferring the liquid forming the aerosol from the liquid reservoir to the evaporation section. Preferably, the evaporation section is located or is located at a downstream end of the means for capillary liquid transfer. In particular, the means for capillary liquid transfer may comprise a wick element. The configuration of the wick element may be a multi-wire wire, a multi-wire rope of material, a mesh, a mesh tube, several concentric mesh tubes, a fabric, sheets of material or foam (or other porous solid) with sufficient porosity, a roll of metal mesh with fine holes or any other arrangement of metal foil, fibers or mesh or any other geometry that has an appropriate size and configuration to implement the capillary action as described herein.

As an example, the means for capillary transport of a liquid may comprise a bundle of threads comprising a plurality of threads. Preferably, the bundle of threads is a bundle of untwisted threads. In a bundle of untwisted threads, the threads of the bundle of threads pass next to each other without crossing each other, preferably along the entire length of the bundle of threads. Likewise, the bundle of threads may comprise a twisted portion in which the threads of the bundle of threads are twisted. The twisted portion can increase the mechanical stability of the bundle of threads. The use of threads for transporting liquids is particularly advantageous since the threads by their nature provide a capillary action. Moreover, in a bundle of threads, the capillary action is enhanced by the narrow gaps formed between the plurality of threads when they are bundled. This applies in particular to a parallel arrangement of threads, along which the capillary action is constant, since the narrow gaps between the threads do not change along the parallel arrangement. For example, the bundle of threads may comprise a bundle portion with a parallel arrangement of threads along at least a portion of its lengthwise extension, in which a plurality of threads may be arranged parallel to each other. The bundle portion with a parallel arrangement of threads may be located at one end portion of the bundle of threads or between both end portions of the bundle of threads. Alternatively, the bundle portion with a parallel arrangement of threads may extend along the entire dimension along the length of the bundle of threads. The bundle of threads may further comprise a branched portion at least at a downstream end portion of the bundle of threads, which preferably corresponds to or is a portion of the evaporation section. In the branched portion, the threads diverge from each other. Such a branched portion may be useful for facilitating the action of the evaporated liquid forming the aerosol on the air path and, thus, for facilitating the formation of the aerosol. It is assumed that the bundle of threads may comprise two branched portions, one at each end portion of the bundle of threads.

As another example, the means for capillary liquid transport may comprise at least one capillary channel. A mesh may be arranged across the downstream end of the capillary channel, in particular across the inner cross-section of the capillary channel at the downstream end of the capillary channel. The mesh may form at least part of the evaporation section. Preferably, the size of the mesh gaps is selected such that the liquid forming the aerosol can form a meniscus in the mesh gaps. The width of the gaps is preferably from 75 micrometers to 250 micrometers. The mesh may comprise a plurality of threads, each thread having a diameter of from 8 micrometers to 100 micrometers, preferably from 8 micrometers to 50 micrometers, and more preferably from 8 micrometers to 39 micrometers.

The mesh, in particular the threads forming the mesh, may comprise or be made of at least one current-collecting material. This advantageously allows the mesh to be used as a current collector for inductively heating the aerosol-forming liquid at the end of the capillary channel located further downstream.

Alternatively, the downstream end of the capillary channel may be an open end (without any arrangement of the internal cross-section of the capillary channel at its downstream end). In this situation, the capillary channel is preferably designed to be inductively heated at least in the downstream end portion. That is, the capillary channel may comprise or be made of a current-collecting material at least in the downstream end portion.

The capillary channel may be formed within a wall element of the aerosol generating device or by means of a capillary gap between several wall elements of the aerosol generating device. For example, the capillary channel may be formed by a capillary gap between an inner wall element forming part of the air pipe and an outer wall element forming the outer body of the aerosol generating device.

It is also possible that the means for capillary transport of liquid comprises at least one capillary tube. As for the capillary channel, the mesh can be arranged at the downstream end of the capillary tube, in particular across the inner cross-section of the capillary tube at the downstream end of the capillary tube. Alternatively, the downstream end of the capillary tube can be an open end (without any arrangement across the inner cross-section of the capillary tube at its downstream end). In this situation, the capillary tube is preferably designed to be inductively heated at least in the downstream end portion. That is to say, the capillary tube can comprise or be made of a current-collecting material at least in the downstream end portion.

The internal cross-section of the capillary channel or capillary tube may be constant in the direction of the fluid flow through the capillary channel or capillary tube, respectively. For example, the internal cross-section of the capillary channel or capillary tube may be circular, oval, elliptical, rectangular or square. The equivalent diameter of the internal cross-section of the capillary channel or capillary tube may be in the range from 0.1 millimeters to 3 millimeters, in particular from 0.1 millimeters to 1.5 millimeters, preferably from 0.1 millimeters to 1 millimeter. In the context of the present document, the term "equivalent diameter" refers to the diameter of a circular region that has the same area as the cross-sectional area of the capillary channel or capillary tube.

As another example, the means for capillary transfer of liquid may comprise two opposing plates forming a capillary gap between them. The width of the capillary gap between the two opposing plates in the direction normal to the two opposing plates may be in the range of 100 micrometers to 500 micrometers. Preferably, the width of the capillary gap is constant in the direction of flow of the fluid through the capillary gap. That is, the two opposing plates are preferably parallel to each other.

A gap retainer may be located at the downstream end of the liquid capillary transfer means, closing the gap between two opposing plates. Advantageously, the gap retainer serves the purpose of separating two plates from each other and closing the gap at the downstream end of the two plates.

At least one of the two, preferably each of the two, plates may comprise one or more perforations (through holes) on the downstream end portion of the means for capillary transfer of liquid, wherein the downstream end portion forms an evaporation section.

At least one of the two, preferably each of the two, plates may comprise a current-collecting material at least at the downstream end portion of the means for capillary liquid transfer or may be made of it. As a result, the means for capillary liquid transfer is capable of performing two functions: transferring and heating the liquid forming the aerosol.

At least one of the two, preferably each of the two, plates may be made of a first material on the end portion of the means for capillary liquid transfer located further downstream and a second material on the end portion of the means for capillary liquid transfer located earlier downstream, or may comprise them, wherein the first and second materials differ from each other. Advantageously, this may allow the end portion of the means for capillary liquid transfer located later downstream to be inductively heated, and the end portion of the means for capillary liquid transfer located earlier downstream to be inductively non-heated.

Similarly, at least one of the two, preferably each of the two, plates may be a two-part plate. In particular, the two-part plate may comprise a first plate element at the downstream end portion of the liquid capillary transfer means comprising one or more perforations, and a second plate element at the upstream end portion of the liquid capillary transfer means having no perforations. For example, the first plate element may be a mesh plate, whereas the second plate element may be a plate with a closed surface. Preferably, the material of the first plate element differs from the material of the second plate element. The material of the first plate element may be designed with the possibility of induction heating, i.e. be a current-collecting material, and the material of the second plate element may not be inductively heated, i.e. electrically non-conductive and non-magnetic.

The two-plate liquid transfer means is particularly advantageous with respect to induction heating. This is due to the fact that the thickness of the plates, which best suits the induction source, can be selected independently of the dimensions of the liquid transfer means in the direction of the fluid flow. This independent choice makes it possible to find an optimal balance between the heat transfer rate and the liquid flow rate in the evaporation section. In addition, due to the possibility of making the capillary gap small, it is possible to increase the efficiency of liquid heating (depending on the plate thickness), since a small gap ensures rapid evaporation of the liquid substrate (instantaneous heating) located between the current-collecting plates. The flat geometry of the plates also contributes to the fact that the air flow passing through the evaporation section is tangential. This advantageously improves the effect of the static pressure drop in the evaporation section and thus the pressure gradient along the capillary liquid transfer means, which draws the liquid from the liquid reservoir into the evaporation section.

As another example, the means for capillary transfer of liquid may comprise a capillary tube having an open end located downstream of the flow, which expands and forms an evaporation section. The internal cross-section of the capillary tube may vary, in particular increase, in the direction of flow of the fluid through the capillary tube. This advantageously makes a separate changing cross-section of the reservoir opening unnecessary. For example, the internal cross-section of the capillary tube may vary in the range from 0.1 millimeters to 5 millimeters, in particular from 0.1 millimeters to 3 millimeters, preferably from 0.1 millimeters to 1.5 millimeters.

The downstream divergent end may be positioned at an angle relative to the rest of the capillary tube. For example, the downstream divergent end may be positioned at an angle of at least 45 degrees, in particular at least 60 degrees, preferably 90 degrees relative to the rest of the capillary tube. This may advantageously allow the outlet opening of the downstream divergent end (where the liquid forming the aerosol evaporates during use) to be aligned relative to the air passing through the evaporation section at the downstream divergent end during use. In particular, the air jet generating element may be designed with the possibility and adapted to generate an air jet which passes tangentially through the outlet opening of the downstream divergent end. Preferably, the capillary tube with the downstream divergent end has the shape of an alpine horn.

Preferably, the capillary tube is designed to be inductively heated at least at the diverging end located downstream. That is, at least at the diverging end located downstream, the capillary tube may comprise or be made of a current-collecting material. By having a bell-shaped evaporation section designed to be inductively heated, the heating efficiency of the evaporation section can advantageously be increased. The remaining sections of the capillary tube may also be designed to be inductively heated. Alternatively, the remaining sections of the capillary tube may not be inductively heated. Thus, the heat capacity of the means for capillary liquid transport is independent of its liquid transport capacity.

In general, the air pipe can be formed by any structural means and can have any shape suitable for passing air through the evaporation section of the means for capillary liquid transfer and preferably further into the user's mouth. In this way, the evaporation section of the means for capillary liquid transfer is exposed to the air flow of the air pipe. In particular, the evaporation section of the means for capillary liquid transfer can be located inside the air pipe. This allows the aerosol-forming liquid evaporated in the evaporation section to be drawn into the air flow and subsequently mixed with air in the expansion zone located downstream of the air jet generating element to thus form an aerosol.

The air pipe may comprise an inlet located upstream of the ejector portion. The air pipe may further comprise an outlet located further downstream of the ejector portion. Preferably, the outlet of the air pipe is part of a mouthpiece that can be placed in the user's mouth to take a puff. In this case, the user's puff initiates low pressure in the outlet, which in turn causes air to enter the air pipe at the inlet of the air pipe located upstream of the ejector portion.

The air jet generating element is preferably designed with the possibility and adapted to generate an air jet which (in use) passes tangentially through the outlet opening or outlet part of the means for capillary liquid transfer. Advantageously, this improves the effect of the static pressure drop in the evaporation section and, therefore, the pressure gradient along the means for capillary liquid transfer, which draws liquid from the liquid reservoir into the evaporation section.

The air jet generating element may comprise at least one jet nozzle. The jet nozzle may be located inside the main air flow path through the air pipe. Similarly, the jet nozzle may provide an additional air flow path entering the main air flow path approximately at the location of the evaporation section or earlier along the flow path from it. The nozzle may be a pipe or tube having a changing cross-sectional area along the direction of the fluid flow through the nozzle. In the nozzle, the fluid velocity increases due to its pressure energy and, thus, may be used to control the flow rate, speed, direction, mass, shape and/or pressure of the fluid flow flowing out of it.

The air jet generating element may comprise at least one air path narrowing in the air pipe. In the context of this document, the term "air path narrowing" refers to a narrowing of the cross-section of the air path through the air pipe. In this sense, a jet nozzle located inside the air flow path through the air pipe (as mentioned above) can also be considered as an air path narrowing.

As an example, the air jet generating element may comprise a slotted plate forming a narrowing of the air duct. The slotted plate may be placed inside the air flow duct of the air pipe. The slotted plate may be a plate having at least one slot, wherein the cross-section of the slot is smaller than the cross-section of the air duct through the air pipe located further along the flow path and earlier along the flow path from the slot, in particular further along the flow path and earlier along the flow path near the slot.

As another example, the air pipe may comprise a guide wall, the distance of which to the axis of the length of the means for capillary transfer of liquid is smaller at the location of the evaporation section than at other locations in the air pipe upstream and downstream of the evaporation section, in particular downstream and upstream near the evaporation section, so that at the location of the evaporation section a narrowing of the air path is formed in the air pipe.

Similarly, the air duct may comprise a guide wall, wherein the narrowing of the air path in the air duct is formed by a minimum distance between the guide wall and the means for capillary transfer of liquid at the location of the evaporation section.

The minimum distance between the guide wall and the means for capillary liquid transfer at the location of the evaporation section can be formed by a lateral expansion, in particular, a venting of the means for capillary liquid transfer in the evaporation section. For example, the lateral expansion or venting of the means for capillary liquid transfer can be formed by an expanding end portion of a capillary tube, the details of which were mentioned in more detail above. Similarly, the lateral expansion or venting of the means for capillary liquid transfer can be formed by a branched portion of the means for liquid transfer, similar to a bundle of threads, the details of which were also mentioned in more detail below.

The minimum distance between the guide wall and the means for capillary transfer of liquid at the location of the evaporation section may also be formed by a lateral recess of the guide wall at the location of the evaporation section, wherein the lateral recess of the guide wall points towards the means for capillary transfer of liquid.

As another example, the air pipe may comprise a guide bushing having a variable cross-section along the axis of the length of the bushing, wherein the evaporation section is located inside the guide bushing within the minimum value of the cross-section so as to form an element generating an air stream. In particular, the guide bushing may comprise a funnel-shaped portion located upstream of the minimum value. In the funnel-shaped portion, the cross-section of the guide bushing is tapered, in particular convexly tapered, toward the minimum value, as seen in the direction further downstream of the air flow through the air pipe. The guide bushing may further comprise a convex portion located downstream of the minimum value. In the convex part, the cross-section of the guide sleeve can first expand, in particular expand concavely, to a maximum value and subsequently narrow, in particular narrow concavely, as seen in the direction further downstream of the air flow through the air duct. Preferably, the convex part forms an expansion zone.

In addition, the aerosol generating device may comprise a mouthpiece. In the context of this document, the term "mouthpiece" refers to an element that is placed in the user's mouth for directly inhaling the aerosol from the article. The mouthpiece may be part of the air tube. Preferably, the mouthpiece comprises a filter. The filter may be used to filter unwanted components of the aerosol. The filter may also comprise additional material, such as a flavoring material, to be added to the aerosol.

According to the present invention, there is also provided an aerosol generating article for use with an aerosol generating device, wherein the aerosol generating article comprises an aerosol generating device according to the present invention and as described herein.

The aerosol-generating article may be a disposable aerosol-generating article or a reusable aerosol-generating article. In the first case, the aerosol-generating article may be a consumable element, in particular a consumable element to be discarded after a single use. In the second case, the aerosol-generating article may be refillable. That is, the liquid reservoir may be refillable with a liquid that forms the aerosol. In any configuration, the aerosol-generating article may further comprise a liquid that forms the aerosol, contained in the liquid reservoir.

In the context of this document, the term "aerosol-forming liquid" refers to a liquid capable of releasing volatile compounds that can form an aerosol when the aerosol-forming liquid is heated. The aerosol-forming liquid is designed to be heated. The aerosol-forming liquid may contain both solid and liquid aerosol-forming material or components. The aerosol-forming liquid may contain a tobacco-containing material containing volatile tobacco flavor compounds that are released from the liquid when heated. Alternatively or additionally, the aerosol-forming liquid may contain a non-tobacco material. The aerosol-forming liquid may further contain an aerosol-forming agent. Examples of suitable aerosol-forming agents include glycerin and propylene glycol. The aerosol-forming liquid may also contain other additives and ingredients, such as nicotine or flavoring agents. In particular, the aerosol-forming liquid may contain water, solvents, ethanol, plant extracts, and natural or artificial flavors. The aerosol-forming liquid may be a water-based aerosol-forming liquid or an oil-based aerosol-forming liquid.

In addition, the aerosol-generating article may comprise a mouthpiece. In the context of this document, the term "mouthpiece" refers to the part of the article that is placed in the user's mouth for directly inhaling the aerosol from the article. Preferably, the mouthpiece comprises a filter. The filter may be used to filter unwanted components of the aerosol. The filter may also comprise additional material, such as a flavoring material, to be added to the aerosol.

The article may have a simple structure. The article may have a housing, which is preferably a rigid housing containing a material that is impermeable to liquid. In the context of this document, "rigid housing" means a housing that is self-supporting. The housing may contain PEEK (polyetheretherketone), PP (polypropylene), PE (polyethylene) or PET (polyethylene terephthalate) or may be made of one of them. PP, PE and PET are particularly economical and easy to mold.

Additional features and advantages of the aerosol generating article according to the present invention have already been described in relation to the aerosol generating device according to the present invention and are thus equally applicable.

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

The aerosol generating device may be designed to accommodate an aerosol generating article. In particular, the aerosol generating device may comprise a receiving cavity for accommodation, intended for accommodation of the aerosol generating article. Similarly, the aerosol generating device may be designed to be connected to the aerosol generating article, for example, by means of a screw connection, a snap connection, and a bayonet connection.

As has already been additionally mentioned above, in such a system, the aerosol generating device, or at least a large part of the components of the aerosol generating device, can be part of the aerosol generating article. This is true in particular for the air nozzle, the liquid reservoir and the means for capillary liquid transfer. That is, the air nozzle, the liquid reservoir and the means for capillary liquid transfer preferably are part of the aerosol generating article. In another configuration, the liquid transfer means and the air nozzle can be part of the aerosol generating device, wherein the liquid reservoir can be part of the aerosol generating article adapted for use with the aerosol generating device, of which the liquid transfer means and the air nozzle are part. Despite this, it is possible to consider the liquid transfer means and the air nozzle as part of the aerosol generating device, although they are separated from other components of the aerosol generating device, such as the liquid reservoir. That is, one part of the aerosol generating device may be a part of the aerosol generating article, such as a liquid reservoir, while another part of the aerosol generating device, such as an air pipe, a means for capillary transfer of liquid and, if present, an induction source, may be a part of the aerosol generating device. If the evaporation section is designed with the possibility of induction heating, then the aerosol generating device preferably comprises an induction source adapted for and designed with the possibility of generating an alternating magnetic field at the location of the evaporation section, when the aerosol generating article is inserted into the aerosol generating device or is coupled with it. Despite this, it is possible to consider the induction source as a part of the aerosol generating device, although it is separated from other components of the aerosol generating device. That is, one part of the aerosol generating device is a part of the aerosol generating article, such as an air pipe, a means for capillary transfer of liquid and preferably also a liquid reservoir, while another part of the aerosol generating device, in particular the induction source, is a part of the aerosol generating device. Alternatively, the induction source may not be considered a part of the aerosol generating device. The details of the induction source have already been described in relation to the aerosol generating device according to the present invention and are thus equally applicable.

As also additionally mentioned above, a heating element, separate from the liquid transfer means, can also be used to heat the evaporation section. The heating element can have or be brought into thermal contact or thermal proximity with the evaporation section. The heating element can be a resistive heating element or an induction heating element. In particular, in the case of a resistive heating element, the heating element can be part of an aerosol generating device.

The aerosol generating device may further comprise a controller for controlling the operation of the aerosol generating system, in particular for controlling the heating operation. Furthermore, the aerosol generating device may comprise a power supply unit supplying electric power used for heating the evaporation section of the means for capillary liquid transfer. Preferably, the power supply unit is a battery, such as a lithium iron phosphate battery. The power supply unit may have a capacity that allows storing sufficient energy for one or more sessions of use by the user.

Additional features and advantages of the aerosol generating system according to the present invention have already been described in relation to the aerosol generating device and the aerosol generating article according to the present invention and are thus equally applicable.

According to the present invention, there is also provided an aerosol generating device for generating an aerosol from an aerosol-forming liquid, wherein the device comprises an aerosol generating device according to the present invention and as described herein. In particular, the aerosol generating device is a stand-alone aerosol generating device, i.e. an aerosol generating device that is not configured to be used with an aerosol-generating article (consumable element). Preferably, in this configuration, the liquid reservoir is refillable.

Further features and advantages of the (stand-alone) aerosol generating device according to the present invention have already been described in relation to the aerosol generating device according to the present invention and are thus equally applicable. Also, the features and advantages described above in relation to the aerosol generating device, the aerosol generating system according to the present invention can be applied to the (stand-alone) aerosol generating device.

The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

Example Ex1: An aerosol generating device for generating an aerosol from an aerosol-forming liquid, wherein the aerosol generating device comprises a liquid reservoir for storing an aerosol-forming liquid, liquid capillary transfer means for transferring the aerosol-forming liquid from the liquid reservoir through an opening in the reservoir into an evaporation section of the liquid transfer means outside the reservoir, and an air pipe for passing an air flow through the evaporation section, wherein the liquid reservoir is a volume compensating liquid reservoir designed to resist capillary absorption of the liquid capillary transfer means, and wherein the air pipe comprises a portion in the form of a pusher containing an air jet generating element and an expansion zone located downstream of the air jet generating element, wherein the air jet generating element is designed with the possibility and is adapted to generate an air jet in an air flow passing through the air branch pipe, which leads to a drop in static air pressure near the evaporation section.

Example Ex2: An aerosol generating device according to example Ex1, wherein the volume compensating liquid reservoir comprises a flexible bag for storing the aerosol-forming liquid and a low-pressure chamber hermetically sealing the flexible bag, wherein the interior of the flexible bag is in fluid communication with the means for capillary transfer of the liquid.

Example Ex3: An aerosol generating device according to example Ex2, wherein the flexible bag is made of plastic, such as polyvinyl chloride, polypropylene, polyethylene, ethylene vinyl acetate.

Example Ex4: An aerosol generating device according to any of example Ex2 or example Ex3, wherein the pressure inside the low pressure chamber acting on the outside of the flexible bag is lower than the ambient pressure, in particular atmospheric pressure, minus the sum of the static pressure of the liquid and the capillary pressure at the upstream end of the reservoir opening (or at the upstream end of the liquid capillary transfer means, where the liquid capillary transfer means has a changing capillary cross-section in the direction of fluid flow through the liquid transfer means).

Example Ex5: An aerosol generating device according to any of examples Ex2-Ex4, wherein the low pressure chamber comprises rigid walls.

Example Ex6: An aerosol generating device according to example Ex1, wherein the volume compensating liquid reservoir comprises a chamber with rigid walls comprising at least one vent hole of a size allowing the aerosol-forming liquid in the liquid reservoir to form a meniscus facing the interior of the liquid reservoir.

An aerosol generating device according to example Ex6, wherein the cross-sectional area of the vent opening is less than the maximum cross-sectional area of the reservoir opening.

Example Ex7: An aerosol generating device according to example Ex6 or example Ex7, wherein the cross-sectional area of the vent opening is smaller than the largest cross-sectional area of the reservoir opening.

Example Ex8: An aerosol generating device according to example Ex1, wherein the volume compensating liquid reservoir comprises at least one elastic partition forming an element in the form of an outer wall of the liquid reservoir.

Example Ex9: An aerosol generating device according to example Ex9, wherein any other wall element of the liquid reservoir, in addition to the elastic partition, is a rigid wall element.

Example Ex10: An aerosol generating device according to any of example Ex9 or example Ex10, wherein the elastic partition has a Young's modulus in the range from 1 MPa to 100 MPa, in particular from 2 MPa to 50 MPa, preferably from 2 MPa to 20 MPa.

Example Ex11: An aerosol generating device according to any of the previous examples, wherein the cross-section of the opening of the reservoir narrows towards the inside of the liquid reservoir.

Example Ex12: An aerosol generating device according to any of the previous examples, wherein the means for capillary transfer of liquid comprises at least one capillary channel.

Example Ex13: An aerosol generating device according to example Ex13, in which a mesh is arranged across the downstream end of the capillary channel, in particular across the internal cross-section of the capillary channel at the downstream end of the capillary channel, wherein the mesh forms at least part of the evaporation section.

Example Ex14: An aerosol generating device according to example Ex14, wherein the mesh comprises or is made of at least one current-collecting material.

Example Ex15: An aerosol generating device according to any of examples Ex13 to Ex15, wherein the capillary channel is formed within a wall element of the aerosol generating device or by means of a capillary gap between several wall elements of the aerosol generating device.

Example Ex16: An aerosol generating device according to any of the previous examples, wherein the means for capillary transfer of liquid comprises at least one capillary tube.

Example Ex17: An aerosol generating device according to any of examples Ex13-Ex17, wherein the internal cross-section of the capillary channel or capillary tube varies, in particular increases, or is constant in the direction of flow of the fluid through the capillary channel or capillary tube, respectively.

Example Ex18: An aerosol generating device according to any of examples Ex13-Ex18, wherein the internal cross-section of the capillary channel or capillary tube is one of circular, oval, elliptical, rectangular or square.

Example Ex19: An aerosol generating device according to any of the previous examples, wherein the means for capillary transfer of liquid comprises two opposing plates forming a capillary gap between them.

Example Ex20: An aerosol generating device according to example Ex20, in which two opposite plates are parallel to each other.

Example Ex21: An aerosol generating device according to any one of example Ex20 or example Ex21, wherein the width of the capillary gap between two opposite plates in a direction perpendicular to the two opposite plates is in the range of 100 micrometers to 500 micrometers.

Example Ex22: An aerosol generating device according to any of the examples Ex20 to Ex22, wherein at least one of the two, preferably each of the two, plates comprises one or more perforations at the downstream end portion of the means for capillary transfer of liquid forming the evaporation section.

Example Ex23: An aerosol generating device according to any of the examples Ex20 to Ex23, wherein at least one of the two, preferably each of the two, plates comprises a current-collecting material at at least a downstream end portion of the means for capillary transfer of liquid or is made of it.

Example Ex24: An aerosol generating device according to any of the examples Ex20 to Ex24, wherein at the downstream end of the means for capillary transfer of liquid a gap lock is arranged, closing the gap between two opposing plates.

Example Ex25: An aerosol generating device according to any of examples Ex20-Ex25, wherein at least one of the two, preferably each of the two, plates comprises a first material at a downstream end portion of the liquid capillary transfer means and a second material at an upstream end portion of the liquid capillary transfer means, or is made of them.

Example Ex26: An aerosol generating device according to any of the previous examples, wherein the means for capillary transfer of liquid comprises a capillary tube having a downstream flared end forming an evaporation section, wherein preferably the internal cross-section of the capillary tube may be constant or may vary, in particular may increase, in the direction of flow of the fluid through the capillary tube.

Example Ex27: An aerosol generating device according to example Ex27, wherein the downstream flared end is positioned at an angle relative to the rest of the capillary tube.

Example Ex28: An aerosol generating device according to example Ex28, wherein the downstream flared end is positioned at an angle of at least 45 degrees, in particular at least 60 degrees, preferably 90 degrees relative to the rest of the capillary tube.

Example Ex29: An aerosol generating device according to any of examples Ex27 to Ex29, wherein the capillary tube with the flared end located downstream has the shape of an alpine horn.

Example Ex30: An aerosol generating device according to any of examples Ex27-Ex30, wherein the air jet generating element is configured and adapted to generate an air jet passing tangentially during use through the outlet of the downstream diverging end.

Example Ex31: An aerosol generating device according to any of the previous examples, wherein the evaporation section is located or arranged at a downstream end portion of the liquid capillary transfer means.

Example Ex32: An aerosol generating device according to any of the previous examples, wherein the means for capillary transfer of liquid is designed with the possibility of induction heating at least in the evaporation section.

Example Ex33: An aerosol generating device according to any of the previous examples, wherein the means for capillary transfer of liquid comprises or is made of a current-collecting material at least in the evaporation section.

Example Ex34: An aerosol generating device according to any of example Ex30 or example Ex31, further comprising an induction source adapted for and capable of generating an alternating magnetic field at the location of the evaporation section.

Example Ex35: An aerosol generating device according to any of the previous examples, comprising a heating element in thermal contact or in thermal proximity with the evaporation section.

Example Ex36: An aerosol generating device according to example Ex36, wherein the heating element is a resistive heating element or an induction heating element.

Example Ex37: An aerosol generating device according to any of the previous examples, wherein the air jet generating element is configured and adapted to generate an air jet passing tangentially through the outlet opening or outlet portion of the liquid capillary transfer means.

Example Ex38: An aerosol generating device according to any of the previous examples, wherein the air jet generating element comprises at least one jet nozzle.

Example Ex39: An aerosol generating device according to any of the previous examples, wherein the air jet generating element comprises at least one air path constriction in the air nozzle.

Example Ex40: An aerosol generating device according to example Ex40, wherein the air jet generating element comprises a plate with a slot forming a narrowing of the air path.

Example Ex41: An aerosol generating device according to example Ex40, in which the air connection comprises a guide wall, the distance of which to the axis of the length of the means for capillary transfer of liquid is smaller at the location of the evaporation section than at other locations in the air connection upstream and downstream of the evaporation section, in particular downstream and upstream near the evaporation section, so that at the location of the evaporation section a narrowing of the air path is formed in the air connection.

Example Ex42: An aerosol generating device according to example Ex40, wherein the air connection comprises a guide wall, wherein the narrowing of the air path in the air connection is formed by a minimum distance between the guide wall and the means for capillary transfer of liquid at the location of the evaporation section.

Example Ex43: An aerosol generating device according to example Ex43, in which the minimum distance is formed by at least a lateral extension, in particular a ventilating means for capillary transfer of liquid in the evaporation section.

Example Ex44: An aerosol generating device according to any of example Ex43 or example Ex44, wherein the minimum distance is formed by a lateral recess of the guide wall at the location of the evaporation section.

Example Ex45: An aerosol generating device according to any of the previous examples, wherein the air pipe comprises a guide sleeve having a variable cross-section along the axis of the length of the sleeve, wherein the evaporation section is located inside the guide sleeve within a minimum cross-sectional value so as to form an air jet generating element.

Example Ex46: An aerosol generating device according to example Ex46, wherein the guide sleeve comprises a funnel-shaped portion upstream of the minimum value.

Example Ex47: An aerosol generating device according to example Ex47, in which, in the funnel-shaped portion, the cross-section of the guide sleeve tapers, in particular tapers convexly, towards a minimum value, as seen in a direction further downstream of the air flow through the air connection.

Example Ex48: An aerosol generating device according to any of the examples Ex46 to Ex48, wherein the guide sleeve comprises a convex portion downstream of the minimum value.

Example Ex49: An aerosol generating device according to example Ex49, in which in the convex portion the cross-section of the guide sleeve expands, in particular expands concavely, to a maximum value and subsequently narrows, in particular narrows concavely, as seen in a direction further downstream of the air flow through the air connection.

Example Ex50: An aerosol-generating article for use with an aerosol-generating device, wherein the aerosol-generating article comprises an aerosol-generating device according to any of the previous examples.

Example Ex51: An aerosol generating system comprising an aerosol generating article according to example Ex51 and an aerosol generating device adapted for use with the aerosol generating article.

Example Ex52: An aerosol generating device for generating an aerosol from an aerosol forming liquid, wherein the device comprises an aerosol generating device according to any one of examples Ex1-Ex50.

The examples will now be further described with reference to figures, where:

Fig. 1-2 shows an aerosol generating device according to a first illustrative embodiment of the present invention;

Fig. 3-4 shows details of the liquid transfer means used in the aerosol generating device of Fig. 1-2;

Fig. 5 shows another embodiment of a liquid transfer means that can be further used in the aerosol generating device according to Figs. 1-2;

Fig. 6 shows an aerosol generating device according to a second illustrative embodiment of the present invention;

Fig. 7-8 shows an aerosol generating device according to a third illustrative embodiment of the present invention; and

Fig. 9-16 shows various embodiments of an air nozzle and a means for capillary transfer of liquid, which are alternatives to the air nozzle and the means for capillary transfer of liquid shown in Fig. 1-8.

Fig. 1 and Fig. 2 schematically illustrate an aerosol generating device 1 for generating an inhalable aerosol from an aerosol-forming liquid 11 according to a first exemplary embodiment of the present invention. The aerosol generating device 1 comprises a liquid reservoir 10 for storing the aerosol-forming liquid 11 and a liquid capillary transfer means 20 for transferring the aerosol-forming liquid 11 from the liquid reservoir 10 through an opening 18 of the reservoir to an evaporation section 21 of the liquid transfer means 20 outside the reservoir 10. There, the aerosol-forming liquid 11 can be evaporated by heating the evaporation section 21. The evaporated liquid is exposed to air flowing through the evaporation section through an air pipe 40 formed by a bottle-shaped guide sleeve 47 surrounding the liquid transfer means 20. The evaporated liquid is mixed with air in such a way that an aerosol is formed, which can then be drawn out, for example, through the mouthpiece 49 of the air pipe 40. The aerosol generating device 1 is designed such that the air flow through the air pipe 40 is caused by a puff of the user, i.e. the user takes a puff at the downstream end of the air path through the air pipe 40. The air path through the air pipe is indicated by dashed and dotted lines in Fig. 2. The downstream end of the air pipe 40 is formed by an outlet opening 48 in the mouthpiece 49. Thus, when the user takes a puff, a low pressure is created at the outlet opening 48, which, in turn, forces air to enter the air pipe 40 through the inlet openings 46, which form the upstream end of the air path through the air pipe 40.

In the embodiment shown in Fig. 1 and Fig. 2, the means 20 for capillary liquid transfer comprises two opposite plates 22, which form a capillary gap 23 between them. Details regarding this two-plate means 20 for liquid transfer are shown in Fig. 3 and Fig. 4 . The width of the capillary gap 23 between the two opposite plates 22 in the direction normal to the two opposite plates 22 is within the capillary ranges, for example in the range from 100 micrometers to 500 micrometers. In particular, the width of the capillary gap 23 is constant in the direction of the flow of the fluid through the capillary gap. That is, the two opposite plates 22 are preferably parallel to each other. A gap retainer 25 is arranged at the downstream end of the liquid transfer means 20, which serves the purpose of separating the two plates 22 from each other and closing the gap 23 at the downstream end of the liquid transfer means 20. Each of the two plates 22 comprises a plurality of perforations 24 (through holes) at the downstream end portion of the liquid capillary transfer means 22, which forms the evaporation section 21. The perforations 24 have a diameter within the capillary ranges, so that the aerosol-forming liquid can form a meniscus in the opening of each of the perforations. The two plates 22 are made of a current-collecting material, for example, stainless steel, which thereby allows the plates 22 to be inductively heated. Due to this, the two-plate liquid transfer means 20 is capable of performing two functions: transferring and heating the aerosol-forming liquid. For heating the liquid transfer means, an induction source 60 comprising an induction coil 61 can be arranged around the air pipe 40, as shown in Fig. 1 and Fig. 2, to generate an alternating magnetic field. The induction coil 61 is arranged around the location of the evaporation section 21 so as to generate an alternating magnetic field which locally penetrates the liquid transfer means 20 only in the evaporation section 21. As a consequence, the liquid transfer means 20 is locally heated only in the evaporation section 21. The field strength can be selected so that the evaporation section 21 is heated to temperatures sufficient to evaporate the liquid forming the aerosol transferred through the liquid transfer means 20 to the perforations 24. There, the evaporated liquid can leave the perforations 24 to enter the air flow passing through the evaporation zone 21. Due to the local heating, the remaining sections of the liquid transfer means 20 can remain at temperatures below the evaporation temperature. Thus, during use, the liquid transfer means 20 has a temperature profile in the direction of its length, which shows an increase in temperature from temperatures below the evaporation temperature of the liquid forming the aerosol (at the upstream end of the liquid transfer means 20) to temperatures above the evaporation temperature (at the downstream end of the liquid transfer means 20). Advantageously, the presence of the remaining sections of the section with a temperature below the evaporation temperature prevents the boiling of the liquid forming the aerosol inside the liquid transfer means 20 upstream of the evaporation section 21, as well as inside the liquid reservoir 10. Due to the small dimensions of the capillary gap 23 and the perforations 24, only a small part of the liquid is present in the evaporation section 21. This advantageously ensures instantaneous heating, i.e. a rapid start of evaporation.

Fig. 5 shows an alternative embodiment of a two-plate liquid transfer means. In this case, each of the plates is a two-part plate comprising a first plate element 27 at the downstream end of the liquid transfer means 20 and a second plate element 28 at the upstream end of the liquid transfer means. In this case, the second plate element 28 is an imperforate plate with a closed surface, and the first plate element 27 is a mesh plate forming the evaporation section 21. The material of the mesh plate 27 is a current-collecting material, i.e. is designed to be inductively heated. In contrast, the material of the second plate element 28 is preferably electrically non-conductive and non-magnetic, and is thus not designed to be inductively heated. Advantageously, this two-part configuration facilitates local delimitation of the heated portion of the liquid transfer means 20 and the evaporation section 21.

As mentioned above, the use of means for capillary liquid transport leads to problems characteristic of the processes governing the physics of capillary action. In particular, this concerns the uncontrolled absorption of the means for capillary liquid transport, which can, in turn, cause undesirable problems with leakage and changes in the amount of liquid available in the evaporation section. In order to have better control over the flow rate of liquid through the means 20 for liquid transport, the aerosol generating device 1 according to the present invention is adapted to generate an inhalation-induced pressure drop in relation to the static pressure near the evaporation section. The pressure drop causes liquid to be drawn from the reservoir 10 through the means 20 for capillary liquid transport into the evaporation section 21. The pressure drop is initiated by an air jet generated in the part 41 in the form of a pusher of the air pipe 40, which comprises an element 42 generating an air jet, and an expansion zone 43 further downstream from the element 41 generating an air jet. In the embodiment shown in Fig. 1 and Fig. 2, the element 42 generating an air jet comprises a plate 43 with a slot, located inside the air flow path of the air pipe, with a slot 44 on each side of the two-plate means 20 for transferring liquid. The cross-section of each slot 44 is smaller than the cross-section of the air path through the air pipe 40 further downstream and earlier downstream of the corresponding slot 44. Thus, each slot 44 forms a narrowing of the air path in the air pipe 40. When passing through the slots 44, the air speed increases as a result of conservation of mass, thereby creating an air jet further downstream of the slots 44 on each side of the two-plate liquid transfer means 20, which leads to a drop in static pressure near the evaporation section 21. The physical mechanism behind the drop in static pressure, as seen under the microscope, is as follows. Fast moving air particles in the air jet expelled into the open atmosphere located further downstream of the openings 44 collide with air particles that are moving randomly and slowly around. The collision pushes the "stationary" air particles further away, which leads to a local pressure drop, which in turn leads to more air particles from the surrounding environment being drawn into the air jet. The air jet thus leaves behind a partial vacuum, which is felt as a pressure drop within the liquid transport means 20, thus causing a pressure gradient along the liquid capillary transport means 20, which draws the liquid from the reservoir 10 through the capillary gap 23 into the evaporation section 21. The air jet further causes the aerosol-forming liquid 11, evaporated in the evaporation section 21, to be drawn into the air stream and subsequently mixed with the air in the expansion zone 43 located downstream of the air jet generating element, in order to thus form an aerosol. As mentioned above, the pressure drop caused by the air flow and thus the liquid flow through the means 20 for capillary liquid transfer are initiated by the user's inhalation, directing the air flow through the air pipe 40. In particular, the flow rate of the liquid from the reservoir 10 through the means 40 for capillary liquid transfer to the evaporation section 21 can be specifically controlled by the user by changing the intensity of the user's inhalation. In order to prevent uncontrolled absorption of the means 20 for capillary liquid transfer, in particular when the aerosol generating device 1 is not used, the liquid reservoir 10 is a so-called volume compensating reservoir, configured to provide a restoring force that counteracts the capillary absorption, i.e. configured to counteract the capillary drawing and static pressure of the liquid, which would otherwise lead to a leak through the means 20 for liquid transfer. Together, the volume compensating liquid reservoir 10 and the air jet generating element 42 form a well-balanced system which, on the one hand, suppresses uncontrolled absorption and thus provides protection against leaks, and on the other hand provides improved control over the flow rate of liquid through the liquid capillary transfer means 20. In the embodiment shown in Fig. 1 and Fig. 2, the volume compensating liquid reservoir 10 is realized by means of a reservoir which comprises a flexible bag 12 for storing an aerosol-forming liquid 11 and a low-pressure chamber 13 which hermetically encloses the flexible bag 12. The interior of the flexible bag is in fluid communication with the liquid capillary transfer means 20 through the opening 18 of the reservoir, whereas the exterior of the flexible bag 12 is exposed to the pressure inside the closed space between the flexible bag 12 and the surrounding chamber. As shown in Fig. 1, the pressure inside the low-pressure chamber 13 is selected to be lower than the ambient pressure, in particular the atmospheric pressure, minus the sum of the static pressure of the liquid and the capillary pressure at the upstream end of the reservoir opening 18. This advantageously helps to counteract the capillary drawing of the liquid transfer means 20 and thus prevent the liquid 11 from leaking out of the flexible bag 12 when the system is not in use and there is no pressure drop near the evaporation section. In contrast, as shown in Fig. 2, when air flows through the air jet generating element 41 during the user's inhalation, which makes the pressure drop near the evaporation section 21 greater than the sum of the static pressure of the liquid and the capillary pressure, the pressure inside the low-pressure chamber 13 exceeds the pressure further downstream. As a result, a pressure gradient is generated along the means 20 for capillary liquid transport in a direction further downstream, which draws the liquid 11 from the flexible bag 12 through the means 20 for capillary liquid transport into the evaporation section 21. After the external pressure drop disappears after the end of the user's inhalation, the liquid 11 remaining inside the means 20 for capillary liquid transport is pushed back into the flexible bag 12 by the ambient pressure, in particular the atmospheric pressure, until the system finally reaches the shown state of equilibrium. Due to the extraction of the liquid, the flexible bag 12 is compressed by a volume equal to the volume of the liquid extracted from the reservoir 10. Preferably, the flexible bag 12 is made of plastic that is impermeable to the fluid. In contrast, the low-pressure chamber preferably comprises rigid walls. That is, the low-pressure chamber is preferably a chamber with rigid walls. As a result, the low-pressure chamber can maintain a low pressure inside and resist deformation both from the inside and from the outside. For example, the walls of the low-pressure chamber can be made of plastic, in particular silicone, PP (polypropylene), PE (polyethylene) or PET (polyethylene terephthalate).

Fig. 6 schematically illustrates an aerosol generating device 101 according to a second exemplary embodiment of the present invention. The arrangement 101 shown in Fig. 6 is similar to the arrangement 1 shown in Fig. 1 and Fig. 2. Therefore, identical or similar features are designated by the same reference numerals, but with an increase of 100. Unlike the arrangement 1 shown in Fig. 1 and Fig. 2, the aerosol generating device 101 shown in Fig. 6, comprises a volume compensating liquid reservoir 110, which is a chamber 113 with rigid walls, containing a vent opening 115. The vent opening 115 has a size in the capillary range, allowing the liquid 111, forming an aerosol, in the liquid reservoir 110 to form a meniscus 116, facing the interior of the liquid reservoir 110. The meniscus 116 provides resistance to the surface tension, moving the liquid through the means 120 for capillary transfer of liquid. The meniscus 116 is deformed in many ways according to the shape of a convex membrane, until the liquid tension in the opening 118 of the reservoir is not balanced. The resistance to a change in volume is inversely proportional to the size of the opening. Preferably, the cross-sectional area of the vent opening 115 is less than the maximum cross-sectional area of the opening 118 of the reservoir. For example, the ventilation opening 115 may have a size in the range of 0.05 millimeters to 3 millimeters, in particular from 0.05 millimeters to 1.5 millimeters, preferably from 0.05 millimeters to 1 millimeter.

Instead of simply relying on the elastic properties of the meniscus formed by the liquid in the vent, the vent may be closed by an elastic baffle which can be deformed under pressure load. The use of an elastic baffle may also allow the size of the vent to be increased beyond the capillary ranges. This is shown in Fig. 7 and Fig. 8 , which schematically illustrates an aerosol generating device 201 according to a third illustrative embodiment of the present invention. Because of this similarity to the arrangement 1 shown in Fig. 1 and Fig. 2 , identical or similar features are, as before, designated by the same reference numerals, but with an increase of 200. Unlike the arrangement 1 shown in Fig. 1 and Fig. 2 , the aerosol generating device 201 shown in Fig. 7 and Fig. 8, comprises a volume compensating liquid reservoir 210 having an elastic partition 216 forming an element in the form of a wall of the liquid reservoir 210. All other elements 217 in the form of a wall of the liquid reservoir 210 are rigid elements in the form of a wall. The elastic partition 216 is made of a thin rubber membrane, which is exposed to the action of the interior of the liquid reservoir on its inner side and to the pressure of the environment, in particular, atmospheric pressure, on its outer side. Like the meniscus 116 in Fig. 6, the elastic partition 216 provides resistance to the surface tension moving the liquid through the means 220 for capillary transfer of the liquid. In particular, as shown in Fig. 7, when the system is not in use and there is no pressure drop near the evaporation section 221, the resistance provided by the elastic partition 216 prevents the liquid 211 from flowing out of the reservoir 210. When the user takes a puff and thus initiates a pressure drop near the evaporation section 221, the elastic partition 216 deforms until the pressure drop is balanced, as shown in Fig. 8. The resistance provided by the elastic partition 216 depends on its Young's modulus. For example, the elastic partition can have a Young's modulus (tensile elasticity modulus) in the range from 1 MPa (megapascals) to 100 MPa (megapascals), in particular from 2 MPa (megapascals) to 50 MPa (megapascals), preferably from 2 MPa (megapascals) to 20 MPa (megapascals).

Each of the liquid reservoirs 10, 110, 210 shown in Fig. 1, 2, 6, 7 and 8 comprises a reservoir opening 18, 118, 218 with which the corresponding means 20, 120, 220 for capillary transfer of liquid is in fluid communication. The reservoir openings 18, 118, 218 may have a changing cross-section in the direction of fluid flow through the reservoir opening. This may help, for example, to counteract changes in the static pressure of the liquid due to changes in the orientation of the device. Preferably, the cross-section of the reservoir opening narrows in the direction upstream of the flow, i.e. towards the inside of the liquid reservoir.

Fig. 9-16 show various embodiments of an air nozzle and a means for capillary transfer of liquid, which are alternatives to the air nozzles and the means for capillary transfer of liquid shown in Fig. 1-8. Features that are identical or similar are designated by the same reference numbers, but with an increase of 100.

In Fig. 9, the means 320 for capillary liquid transfer is identical to the two-plate means 20 for liquid transfer of the aerosol generating device shown in Fig. 1-2. In contrast to the arrangement 1 shown in Fig. 1-2, the air pipe 340 shown in Fig. 9 comprises a guide sleeve 347 having a changing cross-section along the axis of the length of the sleeve, in particular in the part surrounding the means 320 for liquid transfer. The evaporation section 321 is located inside the guide sleeve 347 within the minimum value 346 of the cross-section of the guide sleeve 347. Accordingly, the cross-section of the air path between the guide sleeve 347 and the evaporation section is limited, thereby forming an element 342 generating an air jet. That is, the air jet generating element 342 is realized by a minimum distance between the wall of the guide sleeve 347 and the means 320 for capillary transfer of liquid at the location of the evaporation section 321. In other words, the air jet generating element 342 is realized by a lateral recess of the guide wall of the air pipe 340 at the location of the evaporation section 321, wherein the lateral recess of the guide wall faces the means 320 for capillary transfer of liquid. In the present embodiment, the guide sleeve 347 comprises a funnel-shaped portion 348 upstream of the minimum value 346. In the funnel-shaped portion 348, the cross-section of the guide sleeve 347 convexly tapers toward the minimum value 346, as seen in a direction further downstream of the air flow through the air pipe 340. The guide sleeve 347 further comprises a convex portion 349 located further downstream of the minimum value 346. In the convex portion 349, the cross-section of the guide sleeve 347 first concavely expands and then concavely tapers, as seen in a direction further downstream of the air flow through the air pipe 340. The convex portion 349 forms an expansion zone 343 of the ejector-shaped portion. The guide sleeve 347, in particular the funnel-shaped portion 348, is formed and arranged in such a way as to generate an air jet passing tangentially through the perforations in the evaporation section 321 of the liquid transfer means 320.

In Fig. 10, the air connection 440 is identical to the air connection 340 shown in Fig. 9. In contrast to Fig. 9, the aerosol generating device shown in Fig. 10 comprises a means 420 for transporting liquid, realized by two capillary tubes 422. Each capillary tube 422 has an open end located further downstream of the flow, expanding end 427, forming an evaporation section 421. The internal cross-section of the capillary tubes 422 increases in the direction of the flow of the fluid through the capillary tube 422. Advantageously, the increase in the cross-section makes it unnecessary to have a separate changing cross-section of the reservoir opening. The downstream flared end 427 is positioned at an angle of 90 degrees relative to the rest of the corresponding capillary tube 422, so that the outlet opening of the downstream flared end 427 (where the liquid forming the aerosol evaporates during use) is oriented tangentially relative to the air jet generated by the air jet generating element 442 flowing through the evaporation section 421. Due to the angled downstream flared ends 427, the capillary tubes 422 have the shape of an alpine horn. Like the two-plate liquid transfer means, the capillary tubes 422 are preferably designed with the possibility of induction heating at least at the corresponding downstream flared end 427.

In Fig. 11 , the liquid transfer means 520 is identical to the alpine horn-shaped liquid transfer means 420 shown in Fig. 10. Unlike Fig. 10, the aerosol generating device shown in Fig. 11 comprises an air pipe 540 with a constant cross-section in the part surrounding the evaporation section 521. Instead of a lateral recess in the guide wall of the air pipe, the air jet generating element 542 of the arrangement according to Fig. 11 comprises two jet nozzles 545 adapted to generate an air jet for each of the alpine horn-shaped liquid transfer means 520. Each air jet represents an additional air flow path entering the main air flow path passing through the air pipe 540 in a preferred position around the evaporation section 521 in order to generate a pressure drop near the evaporation section 521. Two jet nozzles 545 are made and arranged so that the corresponding air jet passes substantially tangentially to the outlet of the further downstream diverging end 527 of the associated capillary tube 522 in the form of an alpine horn.

In Fig. 12, the air pipe 640 is identical to the air pipes 340, 440 shown in Fig. 9 and Fig. 10. In contrast to Fig. 9 and Fig. 10, the aerosol generating device shown in Fig. 12 comprises a liquid transport means 620, implemented by a bundle 622 of untwisted threads, comprising a plurality of threads 623 arranged parallel to each other. The threads 623 or at least a part of the threads 623 can be made of a current-collecting material, which thereby makes it possible to inductively heat the liquid transport means 620 by an induction source. Preferably, the induction source is designed and arranged in such a way as to generate an alternating magnetic field substantially only at the location of the evaporation section 621. Advantageously, this results in local heating of the bundle 622 of threads only in the evaporation section 621.

Similar to Fig. 12 , the aerosol generating device shown in Fig. 13 comprises a liquid transport means 720 implemented by a bundle of threads 722. Unlike Fig. 12, the bundle of threads 722 comprises a branched portion 725 at the downstream end portion of the bundle of threads 722, in which the threads 723 diverge from each other. Preferably, the branched portion 725 corresponds to the evaporation section 721. In the branched portion 725. The branched portion 725 may be useful for facilitating the action of the evaporated liquid forming the aerosol on the air path and, thus, for facilitating the formation of the aerosol. In addition, due to the branched portion 725, there is a minimum distance 746 between the sleeve-shaped guide wall 747 of the air pipe 740 and the downstream end portion of the filament bundle 722. The minimum distance 746 forms a narrowing of the air path with the implementation of the element 742 generating the air jet, which gives the required pressure drop at the downstream end portion of the filament bundle 722, i.e. in the evaporation section 721.

In Fig. 14 and Fig. 15 further embodiments of the aerosol generating device are shown, having a central air pipe 840, as well as a means 820 for capillary transfer of liquid outside the air pipe 840, which comprises a capillary channel 823. In both embodiments, the respective central air pipe 840 comprises a plate 843 with a slot, similar to the plate with a slot shown in Fig. 1 and Fig. 2, which forms an element 842 generating an air jet. As can also be seen in Fig. 14 and Fig. 15, the capillary channel 823 is formed by a capillary gap between an element 847 in the form of an inner wall, forming part of the central air pipe 840, and an element 822 in the form of an outer wall, forming, for example, an outer housing of the aerosol generating device. While the embodiment according to Fig. 14 comprises two capillary channels 823, one on each side of the central air pipe 840, the embodiment according to Fig. 15 comprises only one lateral capillary channel 823. A mesh 827 made of a current-collecting material is arranged across the downstream end of each capillary channel 823 so as to form an evaporation section 821 capable of induction heating. The size of the gaps of the mesh 827 is selected so that the aerosol-forming liquid can form a meniscus therein. For example, the width of the gaps is from 75 micrometers to 250 micrometers. During use, the aerosol-forming liquid evaporated by the mesh 827 is drawn into the air stream downstream of the slotted plate 843, where it mixes with the air in the expansion zone 843 so as to form an aerosol.

Fig. 16 shows another embodiment of an aerosol generating device similar to the aerosol generating device shown in Fig. 15. Accordingly, identical or similar features are designated by the same reference numerals, but increased by 100. In contrast to the arrangement shown in Fig. 15, the arrangement shown in Fig. 16, does not include a slotted plate, but a blocking element 946, which forms a narrowing of the air path in the air path along the air pipe 940. The narrowing of the air path includes an element 942 generating an air jet, which generates an air jet flowing through the evaporation section 921, which results in a drop in static air pressure near the evaporation section 921, which draws in the liquid forming the aerosol through the capillary channel 823 of the means 920 for capillary transfer of liquid to the evaporation section 921.

For the purpose of the present description and the appended claims, except where otherwise indicated, all numbers expressing quantities, amounts, percentages, etc., are to be understood as modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therebetween that may or may not be specifically recited herein. Therefore, in this context, the number A is to be understood as A ± 5 percent of A. In this context, the number A may be considered to include numerical values that are within the normal standard error for the measurement of the property that the number A modifies. The number A, in some instances, when used in the appended claims, may deviate by the percentages listed above, provided that the amount by which A deviates does not materially affect the essential and novel characteristic(s) of the claimed invention. Also, all ranges include the disclosed maximum and minimum points and include any intermediate ranges therebetween that may or may not be specifically listed herein.

Claims (15)

1. An aerosol generating device for generating an aerosol from an aerosol forming liquid, wherein the aerosol generating device comprises a liquid reservoir for storing the aerosol forming liquid, liquid capillary transfer means for transferring the aerosol forming liquid from the liquid reservoir through an opening in the reservoir into an evaporation section of the liquid transfer means outside the reservoir, and an air pipe for passing an air flow through the evaporation section, wherein the liquid reservoir is a volume compensating liquid reservoir configured to resist capillary absorption of the liquid capillary transfer means, and wherein the air pipe comprises a portion in the form of an ejector comprising an air jet generating element and an expansion zone located further downstream of the air jet generating element, wherein the air jet generating element is configured to and is located to generate an air jet in an air flow passing through the air pipe, thereby causing a drop in static air pressure near the evaporation section. 2. An aerosol generating device according to claim 1, characterized in that the volume compensating liquid reservoir comprises a flexible bag for storing the liquid that forms the aerosol, and a low pressure chamber hermetically enclosing said flexible bag, wherein the interior of said flexible bag is in fluid communication with the means for capillary transfer of the liquid. 3. An aerosol generating device according to claim 2, characterized in that the pressure inside the low-pressure chamber, acting on the outside of the flexible package, is lower than the ambient pressure, in particular atmospheric pressure, minus the sum of the static pressure of the liquid and the capillary pressure at the end of the means for capillary transfer of liquid located upstream. 4. An aerosol generating device according to claim 1, characterized in that the volume compensating liquid reservoir comprises a chamber with rigid walls containing at least one ventilation opening having a size that allows the aerosol-forming liquid in the liquid reservoir to form a meniscus facing towards the interior of the liquid reservoir. 5. An aerosol generating device according to claim 4, characterized in that the cross-sectional area of the ventilation opening is less than the largest cross-sectional area of the opening of the reservoir. 6. An aerosol generating device according to claim 1, characterized in that the volume-compensating liquid reservoir contains at least one elastic partition forming an element in the form of an outer wall of the liquid reservoir. 7. An aerosol generating device according to claim 6, characterized in that any other element in the form of a wall of said liquid reservoir, in addition to the elastic partition, is a rigid element in the form of a wall. 8. An aerosol generating device according to any one of the preceding claims, characterized in that the means for capillary transfer of liquid comprises at least one capillary channel, and wherein the mesh is arranged across the downstream end of the capillary channel, in particular across the internal cross-section of the capillary channel at the downstream end of said capillary channel, and wherein the mesh forms at least part of said evaporation section. 9. An aerosol generating device according to claim 8, characterized in that the capillary channel is formed inside an element in the form of a wall of the aerosol generating device, or by means of a capillary gap between several elements in the form of a wall of the aerosol generating device. 10. An aerosol generating device according to any of the preceding claims, characterized in that the means for capillary transfer of liquid comprises two opposite plates forming a capillary gap between them. 11. An aerosol generating device according to claim 10, characterized in that at least one of the two, preferably each of the two, plates comprises one or more perforations on the downstream end portion of the means for capillary transfer of liquid forming the evaporation section. 12. An aerosol generating device according to any one of the preceding claims, characterized in that the means for capillary transfer of liquid comprises a capillary tube having a downstream expanding end forming an evaporation section, wherein preferably the internal cross-section of the capillary tube changes, in particular may increase, in the direction of flow of the fluid through the capillary tube. 13. An aerosol generating device according to claim 12, characterized in that the expanding end located further downstream of the flow is positioned at an angle relative to the rest of the capillary tube. 14. An aerosol generating device according to any of the preceding claims, characterized in that the means for capillary transfer of liquid is designed with the possibility of induction heating at least in the evaporation section. 15. An aerosol generating device according to any of the preceding claims, characterized in that the air jet generating element is configured and arranged to generate an air jet passing tangentially through the outlet opening or outlet portion of the means for capillary transfer of liquid.