Aerosol generating device and aerosol generating system

Abstract

The aerosol-generating device comprises a heating chamber (18) for receiving an aerosol-generating substrate (102), the heating chamber comprising a chamber wall (30). A susceptor structure (40) comprises a plurality of inductively heatable susceptors (42) spaced circumferentially about the chamber wall (30) and exposed to an interior volume (20) of the heating chamber (18). A portion (42a) of the susceptor structure may extend from the chamber wall into the interior volume to support the aerosol-generating substrate. A mounting portion (45) of the susceptor structure is embedded in the chamber wall, for example, by molding the chamber wall around the mounting portion.

Description

Technical Field

[0001] The present disclosure generally relates to aerosol generating devices, and more particularly to aerosol generating devices for heating an aerosol generating substrate to generate an aerosol for inhalation by a user. Embodiments of the present disclosure also relate to an aerosol generating system comprising an aerosol generating device and an aerosol generating substrate. The present disclosure is particularly applicable to portable (handheld) aerosol generating devices. Such devices heat an aerosol generating substrate, such as tobacco or other suitable material, by conduction, convection, and / or radiation to generate an aerosol for inhalation by a user, rather than burning it.

Background Art

[0002] In recent years, the popularity and use of risk reduction devices or risk modification devices (also known as aerosol generating devices or vapor generating devices) has grown rapidly as an alternative to the use of conventional tobacco products. A variety of devices and systems are available that heat or warm an aerosol generating substance to generate an aerosol for inhalation by a user.

[0003] Commonly available risk reduction or risk modification devices are substrate-heated aerosol generators or so-called non-combustible heated devices. These devices generate aerosols or vapors by heating an aerosol-generating substrate to a temperature typically in the range of 150°C to 300°C. Heating the aerosol-generating substrate to this temperature range without combustion typically generates vapors that cool and condense to form an aerosol for inhalation by the device's user. Generally speaking, vapors are substances that are in the gaseous phase at temperatures below their critical temperature, meaning that vapors can be condensed into a liquid by increasing pressure without decreasing temperature, while aerosols are fine solid particles or droplets suspended in the air or another gas. However, it should be noted that the terms “aerosol” and “vapor” may be used interchangeably herein, particularly in reference to the form of the inhalable medium generated for user inhalation.

[0004] Currently available aerosol generating devices can heat an aerosol generating substrate using several different methods. One such method involves providing an aerosol generating device that employs an induction heating system. In such a device, an induction coil is provided in the device, and an induction-heatable susceptor is provided to heat the aerosol generating substrate. When the user operates the device, electrical energy is supplied to the induction coil, generating an alternating electromagnetic field. The susceptor couples with the electromagnetic field to induce local eddy currents and / or larger circulating currents flowing within the susceptor. The current flow within the susceptor causes resistive heating. Depending on the material of the susceptor, heating may also occur due to magnetic hysteresis. Heat is transferred from the susceptor to the aerosol generating substrate, for example, by thermal conduction, and as the aerosol generating substrate heats up, aerosols are generated.

[0005] In general, it is desirable to rapidly heat the aerosol generating substrate in order to achieve and maintain a sufficiently high temperature in order to generate vapor. This disclosure aims to provide an aerosol generating device that rapidly heats the aerosol generating substrate to a desired temperature while simultaneously maximizing the energy efficiency of the device. [Overview of the Initiative] [Means for solving the problem]

[0006] According to a first aspect of this disclosure, an aerosol generating device, A heating chamber for receiving at least a portion of an aerosol generating substrate, comprising a heating chamber having chamber walls that define the internal volume of the heating chamber, A susceptor structure comprising a plurality of inductively heatable susceptors spaced apart around the chamber wall and exposed to the internal volume of the heating chamber, The susceptor structure further provides an aerosol generating device that includes a mounting portion embedded in the chamber wall.

[0007] The aerosol generating device / system is configured to heat an aerosol generating substrate without burning it, thereby evaporating at least one component of the aerosol generating substrate, which in turn generates vapor, which is then cooled and condensed to form an aerosol for the user of the aerosol generating device / system to inhale. The aerosol generating device is typically a handheld, portable device. The aerosol generating device / system provides rapid and controlled heating of the aerosol generating substrate while simultaneously maximizing energy efficiency.

[0008] By embedding a portion of the susceptor structure into the chamber wall, it is ensured that the susceptor structure is securely attached to the heating chamber. The embedded portion is surrounded (not necessarily completely surrounded) by the chamber wall material so as to prevent the susceptor structure from being removed from the wall, at least in a direction substantially perpendicular to the wall surface, by friction between the embedded portion and the wall material, or preferably by mechanical interference.

[0009] The susceptors are positioned around the perimeter of the chamber, for example, by thermal conduction, to transfer heat to the aerosol-generating substrate received within the chamber. The susceptors may also be in contact with the aerosol-generating substrate at their positions around the perimeter of the chamber, thereby supporting the aerosol-generating substrate within the chamber. The space between the susceptors around the perimeter of the chamber may provide an air channel between the aerosol-generating substrate and the chamber wall. It is preferable that multiple susceptors are arranged regularly spaced around the chamber wall.

[0010] Preferably, the susceptor structure further comprises an internally extending portion that extends from the chamber wall into the internal volume. The internally extending portion of the susceptor structure can contact the aerosol generating substrate to conduct heat to it and / or support it within the heating chamber, while the other parts of the susceptor structure are not in contact with the substrate.

[0011] The inner portion of the susceptor may be detached from the chamber wall, thereby leaving a radial gap between each susceptor and the chamber wall, which provides an additional air channel through which air can be drawn into the aerosol-generating substrate.

[0012] The susceptor structure may consist of multiple distinct components, each comprising one or more susceptors. Alternatively, the susceptor structure may be a single component. For example, the susceptor structure may be conveniently formed from a single sheet of material, for instance, by punching out a precursor structure from the material and then folding the precursor structure to form the susceptor structure.

[0013] The susceptor structure may include a connecting portion that connects two or more of a plurality of susceptors. Preferably, the connecting portion of the susceptor structure connects all of the plurality of susceptors. The connecting portion may perform a purely mechanical function to join the susceptors to a common physical structure. In some embodiments of the aerosol generating device according to this disclosure, the connecting portion may function as a conductor that allows induced current to flow between the susceptors. In certain embodiments, the connecting portion may connect all of the plurality of susceptors of the susceptor structure in a continuous circuit around a heating chamber.

[0014] The connection portion of the susceptor structure may be at least partially embedded in the chamber wall. This is a convenient way to position the susceptor structure so that a portion of it is embedded in the chamber wall, even though the susceptor itself is not embedded and remains exposed to the internal volume of the heating chamber.

[0015] Additionally or alternatively, each susceptor may be provided with a mounting portion that is embedded in the chamber wall.

[0016] According to another aspect of the present disclosure, an aerosol generating system is provided which comprises the aerosol generating device described above in combination with an aerosol generating substrate, wherein at least a portion of the aerosol generating substrate is received in a heating chamber of the aerosol generating device.

[0017] According to further aspects of this disclosure, a method for manufacturing an aerosol generating device is: To form a susceptor structure equipped with multiple inductively heated susceptors, This involves forming a chamber wall around the susceptor structure. The chamber walls define the internal volume of the heating chamber for receiving at least a portion of the aerosol-generating substrate. An inductively heated susceptor is spaced apart around the chamber wall and exposed to the internal volume of the heating chamber. The susceptor structure is molded to include a mounting portion that is embedded in the chamber wall.

[0018] Preferably, the susceptor structure further comprises an internally extending portion that extends from the chamber wall into the internal volume.

[0019] Forming the chamber wall around an existing susceptor structure is a simple way to securely mount the susceptor structure to the heating chamber. It avoids the need to form a special structure on the chamber wall to fix the susceptor structure to the wall, thus avoiding the need for a separate manufacturing operation to fix the susceptor structure to the wall. The step of forming the chamber wall may include injection molding or any other molding technique suitable for the chamber wall material and the desired structure.

[0020] It is preferable that the chamber walls be made of a material that is substantially neither conductive nor magnetic, so that the chamber walls themselves are not subjected to induction heating.

[0021] The chamber walls may be made of a heat-resistant plastic material. The chamber walls should not degrade when repeatedly exposed to the operating temperature and other physical conditions of the aerosol generating device. A preferred plastic material is polyether ether ketone (PEEK), which is resistant to thermal degradation and has low thermal conductivity, thereby reducing heat conduction from the inside of the heating chamber to the outside of the chamber walls. PEEK is substantially neither conductive nor magnetic.

[0022] The chamber walls may, as an alternative, be made of ceramic material such as alumina or zirconia. Ceramics are generally extremely resistant to thermal degradation, and many of them also have low thermal conductivity while being substantially neither conductive nor magnetic.

[0023] The susceptor structure preferably comprises a conductive and magnetic material, preferably a metallic material. When at least the susceptor of the susceptor structure is formed of such a material, they can be subjected to induction heating. The metallic material is usually selected from the group consisting of stainless steel and carbon steel. The induction-heatable susceptor can, however, comprise any suitable material including, but not limited to, one or more of aluminum, iron, nickel, stainless steel, carbon steel, and their alloys such as nickel-chromium or nickel-copper.

[0024] The aerosol generating device may include, for example, a power supply and a circuit including a control circuit configured to operate at a high frequency. The power supply and the circuit may be configured to operate at a frequency between about 80 kHz and 1 MHz, optionally between about 150 kHz and 250 kHz, and optionally about 200 kHz. The power supply and the circuit can be configured to operate at a higher frequency, such as in the MHz range, depending on the type of induction-heatable susceptor used.

[0025] The aerosol generating substrate may comprise any type of solid or semi-solid material. Exemplary types of aerosol generating solids include powders, granules, pellets, fragments, strands, particles, gels, strips, loose leaf, cut filler, porous materials, foamed materials, or sheets. The aerosol generating substrate may comprise a plant-derived material, particularly tobacco. The aerosol generating material may advantageously comprise, for example, a reconstituted tobacco comprising any one or more of tobacco, cellulose fibers, tobacco stem fibers, and an inorganic filler such as CaCO3.

[0026] Therefore, the aerosol generating device may be equally referred to as a "heated tobacco device", a "heat-not-burn tobacco device", a "device for vaporizing tobacco products", etc., and is construed as a device suitable for achieving these effects. The features disclosed herein are equally applicable to devices designed to vaporize any aerosol generating substrate.

[0027] The aerosol generating substrate may form part of the aerosol generating article and may be surrounded by a paper wrapper. When the aerosol generating substrate is received within the heating chamber of the aerosol generating device, other portions of the aerosol generating article may remain outside the heating chamber, for example, to provide a mouthpiece for the user.

[0028] The aerosol generating article may be substantially formed in the shape of a stick and may generally resemble a cigarette having a tubular region with an aerosol generating substrate disposed therein in a suitable configuration. The aerosol generating article may include a filter segment, for example, comprising cellulose acetate fibers, at the proximal end of the aerosol generating article. The filter segment may constitute a mouthpiece filter and may be coaxially aligned with the aerosol generating substrate. One or more vapor collection regions, cooling regions, and other structures may also be included in some designs. For example, the aerosol generating article may include at least one tubular segment upstream of the filter segment. The tubular segment may function as a vapor cooling region. The vapor cooling region may advantageously enable the heated vapor generated by heating the aerosol generating substrate to be cooled and condensed to form an aerosol having properties suitable for inhalation by the user, for example, through the filter segment.

[0029] The aerosol generating substrate may comprise an aerosol forming agent. Examples of aerosol forming agents include polyhydric alcohols such as glycerin or propylene glycol and mixtures thereof. Typically, the aerosol generating substrate may comprise an aerosol forming agent content between about 5% and about 50% on a dry weight basis. In some embodiments, the aerosol generating substrate may comprise an aerosol forming agent content between about 10% and about 20%, optionally about 15% on a dry weight basis.

[0030] Upon heating, the aerosol generating substrate may release volatile compounds. The volatile compounds may include flavor compounds such as nicotine or tobacco flavorants. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] [Figure 1] This is a schematic cross-sectional view of an aerosol generation system comprising an aerosol generation device and an aerosol generation article that can be positioned within the heating chamber of the aerosol generation device. [Figure 2] Figure 1 is a schematic cross-sectional view of the aerosol generation system, showing the aerosol-generating article positioned within the heating chamber of the aerosol generation device. [Figure 3] Figures 1 and 2 show detailed perspective views of the heating chamber of the aerosol generating device, illustrating one of several induction heating susceptors mounted on the inner surface of the heating chamber and the coil support structure. [Figure 4] Figure 3 is a schematic cross-sectional view from the end of the heating chamber, showing a susceptor structure comprising multiple separate induction-heatable susceptors arranged at intervals around the heating chamber. [Figure 5] Figures 3 and 4 are diagrams showing the details of the susceptor structure. [Figure 6] This diagram, similar to Figure 5, shows a susceptor structure with alternative shapes and dimensions. [Figure 7] This is a schematic cross-sectional view similar to Figure 4, showing the susceptor structure of Figure 6, which is installed inside the heating chamber. [Figure 8] This diagram, similar to Figure 5, shows a susceptor structure with different alternative shapes and dimensions. [Figure 9] This is a schematic cross-sectional view similar to Figure 4, showing the susceptor structure installed inside the heating chamber (Figure 8). [Figure 10] This is a partial perspective view of a heating chamber, showing another method of securing the susceptor to the chamber wall. [Figure 11] This is a partial perspective view of a heating chamber, showing yet another method of securing the susceptor to the chamber wall. [Modes for carrying out the invention]

[0032] Herein, embodiments of the present disclosure will be described with reference to the attached drawings, merely as examples.

[0033] Referring first to Figures 1 and 2, a schematic diagram shows one embodiment of the aerosol generating system 1. The aerosol generating system 1 comprises an aerosol generating device 10 and an aerosol generating article 100 for use with the device 10. The aerosol generating device 10 comprises a body 12 that houses various components of the aerosol generating device 10. The body 12 can have any shape that is adapted to the components described in the various embodiments described herein and is made to be a size that can be comfortably held by a user with one hand without assistance.

[0034] The first end 14 of the aerosol generating device 10, shown on the bottom side of Figures 1 and 2, will be described for convenience as the distal, bottom, base, or lower end of the aerosol generating device 10. The second end 16 of the aerosol generating device 10, shown on the top side of Figures 1 and 2, will be described as the proximal, top, or upper end of the aerosol generating device 10. During use, the user typically orients the aerosol generating device 10 with the first end 14 facing downward and / or distal to the user's mouth, and the second end 16 facing upward and / or close to the user's mouth.

[0035] The aerosol generating device 10 includes a heating chamber 18 positioned within the main body 12. The heating chamber 18 defines an internal volume in the form of a cavity 20 having a substantially circular cross-section for receiving at least a portion of a substantially cylindrical aerosol generating article 100. The heating chamber 18 has a longitudinal axis defining its longitudinal direction. The proximal end 26 of the heating chamber 18 opens toward the second end 16 of the aerosol generating device 10. The heating chamber 18 is typically held at a distance from the inner surface of the main body 12 to minimize heat transfer to the main body 12.

[0036] The aerosol generating device 10 further comprises a power supply 22, which may be one or more batteries, such as rechargeable batteries, and a controller 24.

[0037] The aerosol generating device 10 may optionally include a slide cover 28 that is laterally movable between a closed position (see Figure 1) in which the slide cover 28 covers the open end 26 of the heating chamber 18 to prevent access to the heating chamber 18, and an open position (see Figure 2) in which the slide cover 28 exposes the open first end 26 of the heating chamber 18 to provide access to the heating chamber 18. In some embodiments, the slide cover 28 can be biased to the closed position.

[0038] The heating chamber 18, specifically the cavity 20, is arranged to receive a substantially cylindrical or rod-shaped aerosol generating article 100 of the corresponding shape. The aerosol generating article 100 typically comprises a pre-packaged aerosol generating substrate 102. The aerosol generating article 100 is a disposable and replaceable article (also known as a “consumable”) which may contain, for example, a cigarette as the aerosol generating substrate 102. The aerosol generating article 100 has a proximal end 104 (or mouth end) and a distal end 106. The aerosol generating article 100 further comprises a mouthpiece segment 108 positioned downstream of the aerosol generating substrate 102. The aerosol generating substrate 102 and the mouthpiece segment 108 are arranged coaxially inside a wrapper 110 (e.g., a paper wrapper) to hold the components in place and form a rod-shaped aerosol generating article 100.

[0039] The mouthpiece segment 108 may comprise one or more of the following components (not shown in detail), arranged sequentially and coaxially in the downstream direction, in other words, from the distal end 106 to the proximal (mouth) end 104 of the aerosol generating article 100: a cooling segment, a central hole segment, and a filter segment. The cooling segment typically comprises a hollow paper tube having a thickness greater than the thickness of the wrapper 110. The central hole segment may comprise a cured mixture containing cellulose acetate fibers and a plasticizer, which serves to increase the strength of the mouthpiece segment 108. The filter segment typically comprises cellulose acetate fibers and functions as a mouthpiece filter. As heated vapor flows from the aerosol generating substrate 102 toward the proximal (mouth) end 104 of the aerosol generating article 100, the vapor cools and condenses as it passes through the cooling segment and the central hole segment, forming an aerosol with properties suitable for inhalation by the user through the filter segment.

[0040] The heating chamber 18 has a base portion 32 located at the distal end 34 of the heating chamber 18 and a side wall (or chamber wall) 30 extending between the base portion 32 and the open end 26. The chamber wall 30 and the base portion 32 can be connected to each other and formed integrally as a single component. In the illustrated embodiment, the chamber wall 30 is tubular, and more specifically cylindrical. In other embodiments, the chamber wall 30 may have other suitable shapes, such as a tube with an elliptical or polygonal cross-section. In further embodiments, the chamber wall 30 may be tapered. The chamber wall 30 and the base portion 32 are formed from a heat-resistant plastic material such as polyetheretherketone (PEEK).

[0041] In the exemplary embodiment, the base 32 of the heating chamber 18 is closed, for example, sealed or airtight. That is, the heating chamber 18 is cup-shaped. This ensures that the base 32 prevents air drawn in from the open end 26 from flowing out from the second end 34, and instead guides it through the aerosol generating substrate 102. This also allows the user to insert the aerosol generating article 100 into the heating chamber 18 to a desired distance and not to insert it any further.

[0042] The aerosol generating device 10 further comprises a susceptor structure 40 having a plurality of inductively heatable susceptors 42 spaced apart in the circumferential direction around the peripheral portion 44 of the heating chamber 18.

[0043] The induction-heatable susceptor 42 extends longitudinally into the heating chamber 18. Each induction-heatable susceptor 42 has a length and a width, typically the length being at least five times the width. Each induction-heatable susceptor 42 has an inward-extending portion 42a that extends radially into the heating chamber 18 from the side wall 30. The inward-extending portion 42a may have elongated ribs or, as shown in the drawings, an inwardly deflected portion. The inward-extending portion 42a extends toward and into contact with the aerosol-generating substrate 102, as shown in Figure 4. The inward-extending portion 42a extends radially inward into the heating chamber 18 to a degree sufficient to reduce the effective cross-sectional area of ​​the heating chamber 18. The inward-extending portion 42a thus forms a friction fit with the aerosol-generating substrate 102 and, in particular, with the wrapper 110 of the aerosol-generating article 100, which may cause compression of the aerosol-generating substrate 102, as best seen in Figure 2. Compression of the aerosol generating substrate 102 improves heat conduction between the susceptor 42 and the aerosol generating substrate 102. Those skilled in the art will understand that the inwardly extending portion 42a is not limited to the dimensions and shapes shown in the drawings, and that other dimensions and shapes are also fully within the scope of this disclosure. The inwardly extending portion 42a does not even need to be convex, as long as it extends inward to a distance from the axis of the heating chamber 18 that is less than the distance of the chamber wall 30, so that the aerosol generating substrate 102 contacts the inwardly extending portion 42a rather than the chamber wall 30.

[0044] Figures 3-5 show a susceptor structure 40 consisting of multiple separate susceptors 42 arranged circumferentially around the perimeter 44 of the heating chamber 18 and not mechanically or electrically connected to one another. Each susceptor 42 is mounted inside the heating chamber 18 by a mounting portion 45 that takes the form of a wing-shaped extension of the susceptor 42. The mounting portion 45 is embedded in the chamber wall 30 so that the susceptor 42 is mechanically fixed and cannot be pulled out of the heating chamber 18.

[0045] The mounting portion 45 is embedded in the chamber wall 30 when forming the heating chamber 18. In one manufacturing method, the susceptor structure 40 is placed in a mold (not shown). If the susceptor structure 40 consists of a plurality of separate susceptors 42, as shown in Figures 3-5, the susceptors 42 may need to be temporarily supported in the mold in the desired configuration. The chamber material is then introduced into the mold in liquid form, for example by injection molding, to fill the space around the mounting portion 45. The material is then cooled, cured, or otherwise processed by conventional methods to form a solid chamber wall 30 into which the mounting portion is embedded.

[0046] Those skilled in the art will understand that the mounting portion 45 is not limited to the dimensions and shapes shown in the drawings, and that other dimensions and shapes are also fully within the scope of this disclosure. For example, the wing-shaped mounting portion 45 shown in Figure 5 does not need to extend along the entire length of the susceptor 42. Alternatively, the mounting portion 45 may be formed at one or both ends of each susceptor 42, as shown in Figure 6. The mounting portion 45 does not need to be around the susceptor 42; they can be formed at the rear of the central portion of each susceptor 42, for example, by molding, or by cutting and bending.

[0047] The aerosol generating device 10 includes an electromagnetic field generator 46 for generating an electromagnetic field. The electromagnetic field generator 46 includes a substantially helical induction coil 48. The induction coil 48 has a circular cross-section and extends spirally around a substantially cylindrical heating chamber 18. The induction coil 48 can be excited by a power supply 22 and a controller 24. The controller 24 includes, among other electronic components, an inverter arranged to convert the DC current from the power supply 22 into an AC high-frequency current for the induction coil 48.

[0048] The chamber wall 30 of the heating chamber 18 includes a coil support structure 50 formed on its outer surface 38. In the illustrated embodiment, the coil support structure 50 comprises a coil support groove 52 that extends spirally around the outer surface 38. The induction coil 48 is positioned within the coil support groove 52 and is therefore securely and optimally positioned relative to the induction-heatable susceptor 42.

[0049] To use the aerosol generating device 10, the user displaces the slide cover 28 (if present) from the closed position shown in Figure 1 to the open position shown in Figure 2. The user then inserts the aerosol generating article 100 through the open end 26 of the heating chamber 18 such that the aerosol generating substrate 102 is received within the cavity 20 and at least a portion of the mouthpiece segment 108 protrudes from the open end 26, allowing engagement by the user's lips.

[0050] When the user operates the aerosol generating device 10, the induction coil 48 is energized by the power supply 22 and controller 24, which supply alternating current to the induction coil 48, thereby generating a time-varying alternating electromagnetic field in the induction coil 48. This electromagnetic field couples with the inductively heatable susceptor 42, generating eddy currents and / or magnetic hysteresis losses within the susceptor 42, causing the susceptor 42 to heat up. The heat is then transferred from the inductively heatable susceptor 42 to the aerosol generating substrate 102, for example, by conduction, radiation, and convection. This heats the aerosol generating substrate 102 without combustion or burning, thereby generating vapor. The generated vapor cools and condenses, forming an aerosol for the user of the aerosol generating device 10 to inhale through the mouthpiece segment 108, and more specifically through the filter segment.

[0051] The vaporization of the aerosol-generating substrate 102 is facilitated by the addition of air from the surrounding environment, for example, through the open end 26 of the heating chamber 18, which is heated as it flows between the wrapper 110 of the aerosol-generating article 100 and the inner surface 36 of the chamber wall 30. More specifically, when the user inhales the filter segment, air is drawn into the heating chamber 18 through the open end 26, as indicated by arrow A in Figure 2. The air entering the heating chamber 18 flows between the wrapper 110 and the inner surface 36 of the chamber wall 30, from the open end 26 towards the closed end 34. As described above, the susceptor 42 is in contact with at least the outer surface of the aerosol-generating article 100 and extends within the heating chamber 18 for a distance sufficient to cause at least some degree of compression of the aerosol-generating article 100. As a result, there are no voids around the entire circumferential circumference of the heating chamber 18. Instead, there is an airflow channel in the circumferential region (four equally spaced gap regions) between the susceptors 42, along which air flows from the open end 26 to the closed end 34 of the heating chamber 18. When the air reaches the closed end 34 of the heating chamber 18, it changes direction by approximately 180° and enters the distal end 106 of the aerosol generating article 100. The air is then drawn through the aerosol generating article 100 from the distal end 106 to the proximal (mouth) end 104, along with the generated vapor, as shown by arrow B in Figure 2.

[0052] In some embodiments of the aerosol generating device, there may be more or fewer than four susceptors 42, and therefore a corresponding number of airflow channels formed by the spaces between them. The susceptors 42 are preferably arranged at equal intervals around the chamber wall 30. As shown in Figures 4, 7, and 9, at least the inwardly extending portion 42a of the susceptor 42 may be formed to be away from the chamber wall 30, thereby leaving a radial gap for airflow between the susceptor 42 and the chamber wall 30. The air may be advantageously preheated before entering the aerosol generating substrate 102 by allowing the incoming air to flow over one or both surfaces of the susceptor 42.

[0053] The user can continue to inhale the aerosol as long as the aerosol generating substrate 102 can continue to generate vapor, for example, as long as vaporizable components remain in the aerosol generating substrate 102 that can be vaporized into a suitable vapor. The controller 24 can adjust the magnitude of the alternating current passing through the induction coil 48 to ensure that the temperature of the inductively heatable susceptor 42, and consequently the temperature of the aerosol generating substrate 102, does not exceed a threshold level. Specifically, at a certain temperature depending on the configuration of the aerosol generating substrate 102, the aerosol generating substrate 102 will begin to burn. This is not a desirable effect, and temperatures above this point are avoided. The materials from which the chamber wall 30 and base 32 are formed are selected to withstand repeated heating to a threshold temperature for the expected lifespan of the aerosol generating device.

[0054] To assist in temperature control, in some embodiments, the aerosol generating device 10 is provided with a temperature sensor (not shown). The controller 24 is configured to receive an index of the temperature of the aerosol generating substrate 102 from the temperature sensor and to control the magnitude of the alternating current supplied to the induction coil 48 using this temperature index. In one embodiment, the controller 24 may supply a current of a first magnitude to the induction coil 48 for a first period to heat the inductively heatable susceptor 42 to a first temperature. Thereafter, the controller 24 may supply an alternating current of a second magnitude to the induction coil 48 for a second period to heat the inductively heatable susceptor 42 to a second temperature. The second temperature may be lower than the first temperature. Thereafter, the controller 24 may supply an alternating current of a third magnitude to the induction coil 48 for a third period to reheat the inductively heatable susceptor 42 to the first temperature. This may continue until the aerosol generating substrate 102 is used up (i.e., all the vapor that can be generated by heating has already been generated) or until the user stops using the aerosol generating device 10. In another scenario, once the first temperature is reached, the controller 24 can reduce the magnitude of the alternating current supplied to the induction coil 48 to maintain the aerosol generating substrate 102 at the first temperature for the rest of the session.

[0055] A single inhalation by a user is generally referred to as a "puff." In some scenarios, it is desirable to emulate the experience of smoking a cigarette, which means that the aerosol generating device 10 is capable of holding enough aerosol generating substrate 102 to provide typically 10 to 15 puffs.

[0056] In some embodiments, the controller 24 is configured to count puffs and cut off the current supply to the induction coil 48 after the user has taken 10 to 15 puffs. Puff counting can be performed in a variety of different ways. In some embodiments, the controller 24 determines when the temperature has dropped during a puff, which is caused by cooling as fresh, cold air flows through a temperature sensor (not shown), and this is detected by the temperature sensor. In other embodiments, the airflow is detected directly using a flow detector. Other suitable methods will be obvious to those skilled in the art. In other embodiments, the controller 24 additionally or alternatively cuts off the current supply to the induction coil 48 after a predetermined time has elapsed since the first puff. This can help both reduce power consumption and provide a backup for turning off the aerosol generating device 10 if the puff counter fails to correctly register that a predetermined number of puffs have been taken.

[0057] In some embodiments, the controller 24 is configured to supply alternating current to the induction coil 48 to follow a predetermined heating cycle that takes a predetermined amount of time to complete. Once the cycle is complete, the controller 24 cuts off the supply of current to the induction coil 48. In some cases, this cycle may utilize a feedback loop between the controller 24 and a temperature sensor (not shown). For example, the heating cycle may be parameterized by a series of temperatures to which the inductively heatable susceptor 42 (or more precisely, the temperature sensor) can be heated or cooled. The temperature and duration of such a heating cycle can be experimentally determined to optimize the temperature of the aerosol generating substrate 102. This may be necessary because direct measurement of the temperature of the aerosol generating substrate 102 may be impractical or misleading, for example, if the outer layer and core of the substrate are at different temperatures.

[0058] The power supply 22 is sufficient to raise the aerosol generating substrate 102 in a single aerosol generating article 100 to a maximum first temperature, maintain it at the first temperature, and supply enough vapor for at least 10 to 15 puffs. More generally, in line with emulating the smoking experience, the power supply 22 is usually sufficient to repeat this cycle 10 or even 12 times (raising the aerosol generating substrate 102 to the first temperature and maintaining the first temperature and vapor generation for 10 to 15 puffs), thereby emulating the user experience of smoking a cigarette packet before the power supply 22 needs to be replaced or recharged.

[0059] Generally, the efficiency of the aerosol generating device 10 is improved when as much heat as possible generated by the inductively heatable susceptor 42 is directed towards heating the aerosol generating substrate 102. To this end, the aerosol generating device 10 is configured to provide heat to the aerosol generating substrate 102 in a controlled manner, while typically reducing heat loss to other parts of the aerosol generating device 10. In particular, heat flow to parts of the aerosol generating device 10 handled by the user is kept to a minimum, thereby keeping these parts cool and comfortable to handle.

[0060] Figure 6 shows an alternative configuration of the susceptor structure 40, which is formed integrally as a single component. The susceptor structure 40 comprises four susceptors 42 arranged in a similar configuration to that in Figure 5, but in this embodiment, the susceptors 42 are connected by connecting portions 56 that extend substantially circumferentially around the structure 40 between pairs of adjacent susceptors 42. As shown, the connecting portions 56 form two complete rings around the susceptor structure 40 near its upper and lower ends. This gives the susceptor structure 40 good structural strength and therefore eliminates the need to support the susceptor structure 40 while the chamber wall 30 is formed around it. For this purpose, the connecting portions 56 do not need to be conductive. However, it is preferable that the connecting portions 56 be made of a conductive material, in which case they allow induced currents to flow between different susceptors 42. In the dimensions and shape shown, the connection portion 56 allows the induced current to flow through the complete circuit between all the susceptors 42, as can also be seen in the cross-sectional view of Figure 7. A third possibility is that the connection portion may be, for example, a conductive wire (not shown) that provides an electrical connection between the susceptors 42 but does not provide mechanical support to the susceptor structure 40.

[0061] The susceptor structure 40 shown in Figures 6 and 7 also includes a mounting portion 58. In this embodiment, the mounting portion 58 is provided at the upper end of the susceptor 42. They serve the same purpose as the mounting portion 45 in Figure 5, namely, to securely fix the susceptor structure 40 within the heating chamber 18. In this case as well, the chamber wall 30 of the heating chamber 18 may be formed by molding it around the mounting portion 58, embedding the mounting portion 58 into the completed solid wall, thereby preventing the susceptor structure 40 from detaching from the heating chamber 18. Since the susceptor structure 40 is a single component, the connecting portion 58 may be made rigid enough to hold the susceptor 42 in a defined relationship, and there is no possibility of the single susceptor 42 detaching from the chamber wall 30. Therefore, the mounting portion 58 is only required in combination to prevent the entire susceptor structure 40 from separating from the chamber 18 by sliding upward. As a result of this constraint on the degrees of freedom of movement of the susceptor structure 40, it may not be necessary in this embodiment to embed the mounting portion 58 in the chamber wall 18. For example, the chamber wall 18 may be configured to have a shoulder portion (not shown) at its upper end that engages with the mounting portion 58 to prevent upward movement of the susceptor structure 40. Readers may readily imagine an arrangement in which the susceptor structure 40 is held within the heating chamber 18 by an additional or alternative mounting portion (not shown) formed at the lower end of the susceptor 42.

[0062] The susceptor structure 40 shown in Figure 6 may be formed from a single sheet of material by punching out a precursor structure from a sheet and then folding the precursor structure to form the susceptor structure 40. The material of the sheet must be conductive and permeable, and preferably metallic, as it is for forming the susceptor 42. In the precursor structure (not shown), the four susceptors 42 are in a common plane, but their inwardly extending portions 42a may be formed during the punching process by deforming the sheet of material from the plane. The mounting portion 45 may also be bent from the plane during the punching process or in a subsequent bending process. After the precursor structure is formed, it is folded along lines parallel to the length of the susceptors 42 to form the ring-shaped structure shown in Figure 6. The ends of the precursor structure may be joined by any suitable means, such as soldering, welding, or mechanical engagement of cooperating parts, to create the desired mechanical and / or electrical connections around the susceptor structure 40.

[0063] It is not essential that the susceptor structure 40 is punched out and bent from a sheet of material. Other suitable methods for manufacturing the desired structure, including casting and molding, are also possible. The susceptor 42 and connecting portion 56 may be formed from different materials to optimize their respective functions.

[0064] Figures 8 and 9 show another modification of the susceptor structure 40, which is substantially similar to the structure 40 in Figures 6 and 7 and will not be described in detail. Figure 7 shows that when the connecting portions 56 of that embodiment extend between adjacent susceptors 42, they are located within the cavity 20 of the heating chamber 18. In the embodiments of Figures 8 and 9, the connecting portions 56 have different dimensions and shapes so that they extend to a distance from the axis of the susceptor structure 40 that is greater than the radius of the inner surface 36 of the chamber wall 30. The connecting portions 56 are thereby embedded in the chamber wall 30 when molded around the susceptor structure 40. Thus, in this embodiment, the connecting portions 56 also function as mounting portions that fix the susceptor structure 40 within the heating chamber 18. The mounting portions 58 at the ends of the susceptor 42 in Figure 6 are not necessary in the susceptor structure 40 of Figure 8 and are omitted.

[0065] Those skilled in the art will understand that the connecting portion 56 is not limited to the dimensions and shapes shown in Figures 6-9, and that other dimensions and shapes are also fully within the scope of this disclosure. For example, the connecting portion 56 may be provided on only a single ring and does not need to be axially positioned near the ends of the susceptor structure 40. In further modifications, the continuous connecting portions 56 around the ring may be axially offset from each other, for example, alternately near the upper and lower ends of the structure 40, to facilitate the flow of induced current within a circuit including the axial length of the susceptor 42.

[0066] Figure 10 shows a further modification of a heating chamber 18 for an aerosol generating device 10, having susceptors 42 embedded in the chamber wall 30. Four separate susceptors 42 are present, extending substantially parallel to the axis of the chamber 18. Each susceptor 42 is fixed to the wall 30 by dovetail joints, thereby providing each susceptor 42 with a pair of mounting portions 60, each mounting portion 60 having an angled interface 62 with the material of the chamber wall 30, which prevents the susceptor 42 from separating from the wall substantially vertically. This arrangement may also be achieved by molding the material of the chamber wall 30 in place around the mounting portions 60, as previously described. Alternatively, the same arrangement may be achieved by first forming the chamber wall 30 with channels 64 having a suitable profile, and then sliding the susceptors 42 axially within the channels 64. By reversing this movement, the susceptor 42 can be axially removed from the heating chamber 18 for, for example, replacement or cleaning, while the mounting portion 60 prevents them from accidentally detaching from the chamber wall 30 during use of the device.

[0067] Figure 11 shows another modification similar to Figure 10, except that the susceptors 42 have a different profile. In this case as well, each susceptor 42 is fixed to the wall 30 by dovetail joints, so that a pair of angled interface surfaces 62 between the mounting portion 60 of the susceptor and the material of the chamber wall 30 prevents the susceptor 42 from moving away from the wall in a substantially vertical direction. In Figure 10, each pair of angled interface surfaces 62 converge outward, whereas in Figure 11, each pair of angled interface surfaces 62 converge inward.

[0068] While exemplary embodiments have been described in the preceding paragraphs, it goes without saying that various modifications can be made to these embodiments without departing from the scope of the attached claims. Therefore, the breadth and scope of the claims should not be limited to the exemplary embodiments described above.

[0069] Unless otherwise stated herein or unless clearly inconsistent with the context, any combination of the features described above in all possible variations is encompassed by this disclosure.

[0070] Unless the context clearly indicates otherwise, throughout this specification and the claims, words such as “includes,” “contains,” and “includes” should be interpreted comprehensively, that is, “includes but not limited,” as opposed to an exclusive or exhaustive meaning.

Claims

1. Aerosol generating device (10), A heating chamber (18) for receiving an aerosol generating substrate (102), the heating chamber (18) comprising a chamber wall (30) defining the internal volume (20) of the heating chamber (18), The susceptor structure (40) comprises a plurality of inductively heated susceptors (42) spaced apart around the chamber wall (30) and exposed to the internal volume (20) of the heating chamber (18), The susceptor structure (40) further comprises mounting portions (45, 56, 58, 60) embedded in the chamber wall (30), and inwardly extending portions (42a) that extend from the chamber wall (30) into the internal volume (20) and are separated from the chamber wall (30) so as to leave a radial gap between each susceptor (42) and the chamber wall (30). Aerosol generating device (10).

2. The aerosol generating device (10) according to claim 1, wherein the susceptor structure (40) comprises a connecting portion (56) for connecting two or more of the plurality of susceptors (42).

3. The aerosol generating device (10) according to claim 2, wherein the connection portion (56) of the susceptor structure (40) connects all of the plurality of susceptors (42).

4. The aerosol generating device (10) according to claim 3, wherein the connecting portion (56) of the susceptor structure connects the plurality of susceptors (42) in a continuous circuit around the heating chamber (18).

5. The aerosol generating device (10) according to any one of claims 2 to 4, wherein the connecting portion (56) provides the mounting portion of the susceptor structure (40) which is embedded in the chamber wall (30).

6. The aerosol generating device (10) according to any one of claims 1 to 5, wherein each susceptor (42) is provided with mounting portions (45, 58, 60) that are embedded in the chamber wall (30).

7. A method for manufacturing an aerosol generating device (10), To form a susceptor structure (40) that includes multiple inductively heated susceptors (42), This involves forming a chamber wall (30) around the susceptor structure (40), The chamber wall (30) defines the internal volume (20) of the heating chamber (18) for receiving the aerosol generating substrate (102), The induction heating susceptor (42) is spaced apart around the chamber wall (30) and exposed to the internal volume (20) of the heating chamber (18), The susceptor structure (40) is molded to include mounting portions (45, 56, 58, 60) that are embedded in the chamber wall (30). Methods that include...

8. The method according to claim 7, wherein the susceptor structure (40) further comprises an internally extending portion (42a) that extends from the chamber wall (30) into the internal volume (20).

9. The method according to claim 8, wherein the innerly extending portion (42a) of the susceptor (42) is separated from the chamber wall (30), thereby leaving a radial gap between each susceptor (42) and the chamber wall (30).

10. The method according to any one of claims 7 to 9, wherein the step of forming the chamber wall (30) includes injection molding.

11. The method according to any one of claims 7 to 10, wherein the chamber wall (30) is made of a material that is substantially neither conductive nor magnetic.

12. The method according to any one of claims 7 to 11, wherein the chamber wall (30) comprises a heat-resistant plastic material, preferably polyetheretherketone (PEEK).

13. The method according to any one of claims 7 to 11, wherein the chamber wall (30) comprises a ceramic material.

14. The method according to any one of claims 7 to 13, wherein the step of forming the susceptor structure (40) includes punching out a precursor structure and then folding the precursor structure to form the susceptor structure (40).

15. The method according to any one of claims 7 to 14, wherein the susceptor structure (40) comprises a conductive and magnetically permeable material, preferably a metallic material.

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