Induction heating assembly for aerosol generation device

Abstract

The induction heating assembly (11) for the aerosol generating device (10) includes an induction coil (48) for generating an electromagnetic field and an inductively heatable susceptor (42) having a first portion (54) and a second portion (56) comprising the same susceptor material. The first portion (54) is positioned relative to the induction coil (48) such that it is inductively heated by the electromagnetic field, and the second portion (56) is positioned relative to the induction coil (48) such that it is not inductively heated by the electromagnetic field. The induction heating assembly (11) further includes a temperature sensor (60) in contact with the second portion (56) of the inductively heatable susceptor (42).

Description

Technical Field

[0001] The present disclosure generally relates to an induction heating assembly for an aerosol-generating device, and more particularly to an induction heating assembly for heating an aerosol-generating substrate to generate an aerosol for a user of the aerosol-generating device to inhale. Embodiments of the present disclosure also relate to an aerosol-generating device including the induction heating assembly. 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, not by combustion, but by conduction, convection and / or radiation to generate an aerosol for a user to inhale.

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) have grown rapidly as an alternative to the use of conventional tobacco products. A variety of devices and systems are available for heating or warming an aerosol-forming substance to generate an aerosol for a user to inhale.

[0003] Commercially available risk reduction devices or risk modification devices are generally substrate-heated aerosol-generating devices or so-called heat-not-burn devices. This type of device generates an aerosol or vapor by heating an aerosol-generating substrate typically to a temperature in the range of 150°C to 300°C. When the aerosol-generating substrate is heated to a temperature within this range without burning or combusting it, vapor is generated which typically cools and condenses to form an aerosol for a user of the device to inhale.

[0004] Aerosol generating devices currently available can supply heat to an aerosol generating substrate using one of several different methods. One such method is to provide an aerosol generating device that employs an induction heating system. In such a device, an induction coil is provided within 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, which then generates an alternating electromagnetic field. The susceptor couples with this electromagnetic field to generate heat, which is transferred to the aerosol generating substrate, for example, by conduction, and as the aerosol generating substrate heats up, an aerosol is generated. [Overview of the project] [Problems that the invention aims to solve]

[0005] Generally, it is desirable to rapidly heat the aerosol-generating substrate to a temperature high enough to generate vapor and to maintain that temperature. To generate an aerosol with appropriate properties, the temperature of the aerosol-generating substrate must be carefully controlled, and therefore, the ability to precisely control the heating temperature is desirable. This disclosure aims to address this need. [Means for solving the problem]

[0006] According to a first aspect of this disclosure, an induction heating assembly for an aerosol generating device is provided, which induction heating assembly is An induction coil for generating an electromagnetic field, An inductively heatable susceptor comprising a first part, which is positioned relative to an induction coil so as to be inductively heated by an electromagnetic field, and a second part, which is positioned relative to the induction coil so as not to be inductively heated by an electromagnetic field, wherein the first part and the second part comprise the same susceptor material, A temperature sensor in contact with the second part of the induction heating susceptor Includes.

[0007] According to a second aspect of this disclosure, an aerosol generating device is provided, which aerosol generating device is An induction heating assembly according to a first embodiment, A power supply arranged to provide power to the induction coil and Includes.

[0008] The induction heating assembly is configured to heat the aerosol-generating substrate without burning it, thereby evaporating at least one component of the aerosol-generating substrate, and thereby generating heated vapor, which is cooled and condensed to form an aerosol for inhalation by the user of the aerosol-generating device. The aerosol-generating device is typically a handheld, portable device.

[0009] Generally speaking, vapor is a substance that is in the gaseous phase at temperatures below its critical temperature, meaning that vapor can be condensed into a liquid by increasing the pressure without lowering the temperature, while aerosol is a mixture of fine solid particles or droplets suspended in air or another gas. However, it should be noted that in this specification, the terms “aerosol” and “vapor” may be used interchangeably, particularly in reference to the form of inhalable media produced for inhalation by the user.

[0010] Heat is conducted from the first part of the inductively heatable susceptor to the second part of the inductively heatable susceptor, and therefore the temperature of the first part of the inductively heatable susceptor can be measured by a temperature sensor in contact with the second part of the inductively heatable susceptor. Since the second part of the inductively heatable susceptor is located outside the electromagnetic field, the temperature sensor is also located outside the electromagnetic field. Thus, induction heating of the temperature sensor is substantially or completely avoided, thereby ensuring that accurate measurements of the temperature of the inductively heatable susceptor are obtained.

[0011] A first portion of the inductively heatable susceptor may be surrounded by an induction coil, and a second portion of the inductively heatable susceptor may be located outside the induction coil. The first portion of the inductively heatable susceptor may be located within the electromagnetic field generated by the induction coil, and the second portion of the inductively heatable susceptor and the temperature sensor may be located substantially outside the electromagnetic field. This configuration ensures that induction heating of the temperature sensor is substantially or completely avoided, thereby ensuring accurate temperature measurements of the inductively heatable susceptor.

[0012] An induction heating assembly may include a heating chamber for receiving at least a portion of an aerosol-generating substrate, and an induction coil may extend around the heating chamber. A first portion of the induction-heatable susceptor may be located inside the heating chamber, and a second portion of the induction-heatable susceptor may be located outside the heating chamber. By locating the second portion of the induction-heatable susceptor outside the heating chamber, a temperature sensor can be easily positioned in contact with the second portion, thus improving the manufacturability and / or assembly of the induction heating assembly.

[0013] The heating chamber may include chamber walls that define the internal volume of the heating chamber.

[0014] The heating chamber may have a longitudinal axis defining its length. The induction-heatable susceptor may be elongated in the longitudinal direction of the heating chamber. The induction-heatable susceptor may be mounted on the inner surface of the chamber wall. The elongated induction-heatable susceptor is efficiently heated in the presence of an electromagnetic field, and its elongated shape ensures that the aerosol-generating substrate is heated rapidly and uniformly along its length. This maximizes the energy efficiency of the aerosol-generating device. A second portion of the induction-heatable susceptor may protrude from the end of the heating chamber and through the chamber wall. A temperature sensor can be easily positioned in contact with the second portion of the induction-heatable susceptor.

[0015] Multiple induction-heatable susceptors may be spaced apart around the inner surface of the chamber wall. By providing multiple induction-heatable susceptors, more rapid and uniform heating of the aerosol-generating substrate can be achieved. The induction heating assembly may include multiple temperature sensors, which may be arranged such that a second portion of each induction-heatable susceptor is in contact with the corresponding temperature sensor. Using multiple temperature sensors, one of which is in contact with the second portion of the corresponding induction-heatable susceptor, allows for a more accurate and reliable determination of the temperature inside the heating chamber, for example, based on the average of multiple temperature measurements.

[0016] The chamber wall may include multiple susceptor mounts formed within or on its inner surface for mounting multiple inductively heated susceptors. The susceptor mounts facilitate the mounting of the inductively heated susceptors and thus simplify the manufacturing and assembly of the induction heating assembly.

[0017] The chamber wall may include a coil support structure that can be formed within or on the outer surface to support the induction heating coil of the electromagnetic field generator. The coil support structure facilitates the installation of the induction heating coil and allows for optimal positioning of the induction heating coil relative to the induction-heatable susceptor. Thus, the induction-heatable susceptor is heated efficiently, thereby improving the energy efficiency of the induction heating assembly and the aerosol generating device. Providing a coil support structure also facilitates the manufacturing and assembly of the induction heating assembly.

[0018] The coil support structure may include a coil support groove. The coil support groove may extend helically around the outer surface of the chamber wall. The coil support groove is particularly suitable for receiving a helical induction heating coil. Thus, a helical induction heating coil may extend around the heating chamber. The induction heating coil may include Litz wire or Litz cable. However, it will be understood that other materials may also be used. The circular cross-section of the helical induction heating coil facilitates the insertion of the aerosol-generating substrate into the heating chamber, ensuring uniform heating of the induction-heatable susceptor and thus the aerosol-generating substrate.

[0019] The induction heating coil may be configured to operate with a fluctuating electromagnetic field having a magnetic flux density of approximately 20 mT to approximately 2.0 T at the point of maximum density during use.

[0020] The heating chamber may be substantially tubular, and the inductively heatable susceptors may be spaced apart around the periphery of the substantially tubular heating chamber. The heating chamber may be substantially cylindrical, and the inductively heatable susceptors may be spaced circumferentially around the substantially cylindrical heating chamber. Thus, the heating chamber may be configured to accept a substantially cylindrical aerosol-generating substrate, and since aerosol-generating substrates in the form of aerosol products are often packaged and sold in a cylindrical shape, this cylindrical aerosol-generating substrate may be advantageous.

[0021] The heating chamber may have a longitudinal axis defining its length. Each induction-heatable susceptor may be elongated in the longitudinal direction of the heating chamber. Each induction-heatable susceptor may have a length and a width, and in one embodiment, the length may be at least five times the width. The elongated induction-heatable susceptor is efficiently heated in the presence of an electromagnetic field, and its elongated shape ensures that the aerosol-generating substrate is heated rapidly and uniformly along its length. This maximizes the energy efficiency of the induction heating assembly and the aerosol-generating device.

[0022] At least one of the plurality of inductively heatable susceptors may have at least one inwardly extending portion that extends into the heating chamber from the inner surface of the chamber wall, for example, to compress the aerosol-forming substrate. The inwardly extending portion may form a frictional engagement with the aerosol-forming substrate. In some embodiments, each of the plurality of inductively heatable susceptors may have one of the inwardly extending portions, and the plurality of inwardly extending portions may compress the aerosol-forming substrate and in particular form a frictional engagement with the aerosol-forming substrate. One or more inwardly extending portions reduce the cross-sectional area of the heating chamber and thereby compress the aerosol-forming substrate disposed in the heating chamber during use. By compressing the aerosol-forming substrate, heat can be efficiently transferred by the aerosol-forming substrate, achieving more rapid heating and at the same time maximizing energy efficiency.

[0023] The heating chamber may comprise a substantially non-conductive and non-magnetic material. For example, the heating chamber may comprise a heat-resistant plastic material such as polyetheretherketone (PEEK). The heating chamber itself is not heated by the electromagnetic field generated by the induction coil during operation of the aerosol-generating device, thereby ensuring that the energy input to the first part of the inductively heatable susceptor is maximized. This then helps to ensure that the energy efficiency of the inductive heating assembly and the aerosol-generating device is maximized. The aerosol-generating device also remains cool to the touch, ensuring maximum user comfort.

[0024] The temperature sensor may be selected from the group consisting of thermocouples, thermistors and resistance temperature detectors (RTDs). However, other types of temperature sensors may be utilized.

[0025] An induction-heatable susceptor may contain metal. The metal is typically selected from the group consisting of stainless steel and carbon steel. However, an induction-heatable susceptor can contain 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. When an electromagnetic field is applied near the susceptor, each induction-heatable susceptor generates heat due to the energy conversion from electromagnetic to heat caused by eddy currents and magnetic hysteresis losses.

[0026] The aerosol generating device may include a power supply and a controller (e.g., 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 of about 80 kHz to 1 MHz, optionally about 150 kHz to 250 kHz, and optionally about 200 kHz. The power supply and the circuit may be configured to operate at a higher frequency, such as in the MHz range, depending on the type of induction-heatable susceptor used.

[0027] The aerosol generating substrate may contain any type of solid or semi-solid substance. Exemplary types of aerosol generating solids include powders, granules, pellets, shreds, strands, particles, gels, strips, loose leaf, cut filler, porous materials, foamed materials, or sheets. The aerosol generating substrate may contain plant-derived materials, particularly tobacco. The aerosol generating substrate may advantageously contain, for example, a reconstructed tobacco containing tobacco and any one or more of inorganic fillers such as cellulose fibers, tobacco stem fibers, and CaCO3.

[0028] Therefore, the aerosol generating device may be referred to as a "heated tobacco device", a "heat-not-burn tobacco device", a "device for vaporizing tobacco products", etc., and is interpreted as a device suitable for realizing these effects. The features disclosed herein are equally applicable to devices designed to vaporize any aerosol generating substrate.

[0029] The aerosol-generating substrate may form part of the aerosol product and may be wrapped in packaging paper.

[0030] The aerosol product may be formed substantially in the shape of a stick, generally similar to a cigarette, and has a tubular region having an aerosol-generating substrate arranged in a preferred configuration. The aerosol product may include a filter segment at its proximal end, for example, containing cellulose acetate fibers. The filter segment may constitute a mouthpiece filter and may be aligned coaxially with the aerosol-generating substrate. Some designs may also include one or more vapor collection regions, cooling regions, and other structures. For example, the aerosol product 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 allow heated vapor generated by heating the aerosol-generating substrate to cool and condense to form an aerosol with properties suitable for inhalation by the user, for example, through the filter segment.

[0031] The aerosol-generating substrate may contain 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 contain an aerosol-forming agent content of about 5% to about 50% on a dry weight basis. In some embodiments, the aerosol-generating substrate may contain an aerosol-forming agent content of about 10% to about 20%, and optionally about 15%, on a dry weight basis.

[0032] Aerosol-generating substrates may release volatile compounds when heated. These volatile compounds may include nicotine or flavoring compounds such as tobacco flavorings. [Brief explanation of the drawing]

[0033] [Figure 1] This is a schematic cross-sectional view of an aerosol generation system, which includes an aerosol generation device and an aerosol product ready to be placed in 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 product placed in the heating chamber of the aerosol generation device. [Figure 3] Figures 1 and 2 are detailed perspective views of the induction heating assembly of the aerosol generation device, showing multiple induction-heatable susceptors mounted on the inner surface of the heating chamber and a coil support structure. [Figure 4] Figure 3 is a schematic cross-sectional view of the induction heating assembly, showing multiple induction-heatable susceptors spaced apart around the periphery of the heating chamber. [Figure 5] Figure 3 is a magnified view of the upper end of the induction heating assembly shown. [Figure 6] Figures 3 and 5 show the external view of the upper end of the induction heating assembly. [Modes for carrying out the invention]

[0034] Herein, embodiments of the present disclosure will be described with reference to the accompanying drawings, merely as examples.

[0035] First, referring to Figures 1 and 2, an example of an aerosol generation system 1 is schematically shown. The aerosol generation system 1 includes an aerosol generation device 10 and an aerosol product 100 for use with the device 10. The aerosol generation device 10 includes a body 12 that houses various components of the aerosol generation device 10. The body 12 can have any shape, which is sized to accommodate the components described in the various embodiments described herein and which is sized so that a user can comfortably hold it with one hand.

[0036] The first end 14 of the aerosol generating device 10, shown on the bottom side in Figures 1 and 2, will be described for convenience as the distal side, 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 in Figures 1 and 2, will be described as the proximal side, top, or upper end of the aerosol generating device 10. During use, the user typically orients the aerosol generating device 10 so that the first end 14 is facing downward and / or distal to the user's mouth, and the second end 16 is facing upward and / or proximal to the user's mouth.

[0037] The aerosol generating device 10 includes an induction heating assembly 11 located within a main body 12. The induction heating assembly 11 includes a heating chamber 18. The heating chamber 18 defines an internal volume in the form of a cavity 20 having a substantially cylindrical cross-section for receiving the aerosol product 100. The heating chamber 18 has a longitudinal axis defining its longitudinal direction and is formed from a heat-resistant plastic material such as polyetheretherketone (PEEK). The aerosol generating device 10 further includes a power source 22, one or more batteries which may be rechargeable, and a controller 24.

[0038] The heating chamber 18 is open toward the second end 16 of the aerosol generating device 10. In other words, the heating chamber 18 has a first end 26 that is open toward the second end 16 of the aerosol generating device 10. The heating chamber 18 is usually held spaced apart from the inner surface of the body 12 in order to minimize heat transfer to the body 12.

[0039] The aerosol generating device 10 may optionally include a slide cover 28 that is movable in the short direction between a closed position (see Figure 1) in which the slide cover 28 covers the open first end 26 of the heating chamber 18 and prevents 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 and provides access to the heating chamber 18. In some embodiments, the slide cover 28 can be biased to the closed position.

[0040] The heating chamber 18, specifically the cavity 20, is arranged to receive a substantially cylindrical or rod-shaped aerosol product 100 of the corresponding shape. Typically, the aerosol product 100 includes a pre-packaged aerosol-generating substrate 102. The aerosol product 100 is a disposable, replaceable article (also known as a “consumable”) which may include, for example, a cigarette as the aerosol-generating substrate 102. The aerosol product 100 has a proximal end 104 (or mouth end) and a distal end 106. The aerosol product 100 further includes 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 within a wrapper 110 (e.g., a paper wrapper) to hold the components in place and form a rod-shaped aerosol product 100.

[0041] The mouthpiece segment 108 may include one or more of the following components (not shown in detail), namely a cooling segment, a central hole segment, and a filter segment, 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 product 100. The cooling segment typically includes a hollow paper tube having a thickness greater than the thickness of the wrapper 110. The central hole segment may include a cured mixture containing cellulose acetate fibers and a plasticizer, which functions to increase the strength of the mouthpiece segment 108. The filter segment typically includes 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 product 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.

[0042] The heating chamber 18 has a base 32 (located at the second end 34 of the heating chamber 18) and a side wall (or chamber wall) 30 extending between the base 32 and the open first end 26. The side wall 30 and the base 32 can be connected to each other and formed integrally as a single component. In the illustrated embodiment, the side wall 30 is tubular, and more specifically cylindrical. In other embodiments, the side wall 30 may have other preferred shapes, such as a tube with an elliptical or polygonal cross-section. In yet another embodiment, the side wall 30 may be tapered.

[0043] In the illustrated 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 first 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 product 100 into the heating chamber 18 to a desired distance and not to insert it further.

[0044] The side wall 30 of the heating chamber 18 has an inner surface 36 and an outer surface 38. Multiple susceptor mounts 40 are formed on the inner surface 36 and spaced circumferentially around the inner surface 36. The induction heating assembly 11 includes multiple induction-heatable susceptors 42 attached to the susceptor mounts 40, and so the induction-heatable susceptors 42 are spaced circumferentially around the periphery 44 of the heating chamber 18.

[0045] The induction-heatable susceptor 42 is elongated in the longitudinal direction of 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 inwardly extending portion 42a that extends radially into the heating chamber 18 from the side wall 30. The inwardly extending portion 42a may include an elongated ridge as shown in Figures 3 to 5, which can be easily formed during the manufacture of the induction-heatable susceptor 42. The inwardly extending portion 42a is not limited to the geometry shown in Figures 3 to 5, and it will be understood by those skilled in the art that other geometry is also entirely within the scope of this disclosure.

[0046] The inwardly extending portion 42a extends toward and into contact with the aerosol-generating substrate 102, as shown in Figure 4. The inwardly 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. Thus, the inwardly extending portion 42a forms a frictional engagement with the aerosol-generating substrate 102, more specifically the wrapper 110 of the aerosol product 100, which can cause compression of the aerosol-generating substrate 102, as best seen in Figure 2. Compression of the aerosol-generating substrate 102 improves heat conduction through the aerosol-generating substrate 102, for example by removing voids, and each inwardly extending portion 42a may extend inward across the heating chamber 18 by a distance of 3% to 7%, for example, about 5%, of the span distance of the heating chamber 18.

[0047] The induction heating assembly 11 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 helically 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 a DC current from the power supply 22 into an AC high-frequency current for the induction coil 48.

[0048] The side wall 30 of the heating chamber 18 includes a coil support structure 50 formed on the outer surface 38. In the illustrated example, the coil support structure 50 includes 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] Each induction-heatable susceptor 42 has a first portion 54 surrounded by the induction coil 48 (i.e., located within the envelope of the cross-section of the induction coil 48) and a second portion 56 located outside the envelope of the cross-section of the induction coil 48. As a result, during the operation of the aerosol generating device 10, the first portion 54 of each induction-heatable susceptor 42 is located within the electromagnetic field generated by the induction coil 48 and is therefore inductively heated by the electromagnetic field, while the second portion 56 of each induction-heatable susceptor 42 is located outside the electromagnetic field generated by the induction coil 48 and is therefore not inductively heated by the electromagnetic field.

[0050] Each inductively heatable susceptor 42 is a continuous component in which the first part 54 and the second part 56 contain the same susceptor material. Therefore, when the first part of each inductively heatable susceptor 42 is inductively heated during use of the aerosol generating device 10, heat is conducted from the first part 54 to the second part 56, and the temperature of the second part 56 of each inductively heatable susceptor 42 matches the temperature of the first part 54.

[0051] The side wall 30 of the heating chamber 18 includes at least one notch 58, which corresponds to the location of a second portion 56 of at least one of the multiple inductively heated susceptors 42. The notch 58 extends completely through the side wall 30, exposing at least a portion of the second portion 56 of the inductively heated susceptor 42, thereby allowing access to that portion from the outer surface 38 of the side wall 30.

[0052] The induction heating assembly 11 further includes a temperature sensor 60, which may be, for example, a thermocouple, a thermistor, a resistance temperature detector (RTD), or any other suitable temperature sensor. The temperature sensor 60 is positioned within the notch 58 in direct contact with the second portion 56 of the induction-heatable susceptor 42. Thus, the temperature of the second portion 56 can be measured directly by the temperature sensor 60, and since the temperature of the second portion 56 of the susceptor 42 is the same as the temperature of the first portion 54, the temperature of the first portion 54 can be accurately measured. Advantageously, since the second portion 56 of the induction-heatable susceptor 42 is located outside the induction coil 48 and therefore outside the generated electromagnetic field, the temperature sensor 60 is also located outside the induction coil 48 and therefore outside the generated electromagnetic field. Thus, induction heating of the temperature sensor 60 and its components is avoided, and accurate temperature measurements can be reliably obtained. The temperature sensor 60 is operably coupled to the controller 24 by one or more connectors not shown in the drawings.

[0053] To use the aerosol generating device 10, the user moves 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 product 100 into the heating chamber 18 through the open first end 26, so that the aerosol generating substrate 102 is received into the cavity 20 and the proximal end 104 of the aerosol product 100 is positioned at the open first end 26 of the heating chamber 18, with at least a portion of the mouthpiece segment 108 protruding from the open first end 26 to allow engagement by the user's lips.

[0054] When the user activates the aerosol generating device 10, the induction coil 48 is excited by the power supply 22 and controller 24 that 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 first portion 54 of the inductively heatable susceptor 42, generating eddy currents and / or magnetic hysteresis losses in the first portion 54 of the susceptor 42, thereby heating the susceptor. As described above, the heat generated in the first portion 54 of the susceptor 42 is conducted to the second portion 56 of the susceptor 42. The heat is also transferred from the inductively heatable susceptor 42, mainly the first portion 54 of the inductively heatable susceptor 42, to the aerosol generating substrate 102, for example, by conduction, radiation, and convection. As a result, the aerosol generating substrate 102 is heated without combustion, thereby generating vapor. The generated vapor is cooled and condensed to form an aerosol that can be inhaled by the user of the aerosol generating device 10 through the mouthpiece segment 108, or more specifically, the filter segment.

[0055] The vaporization of the aerosol-generating substrate 102 is facilitated by adding air from the surrounding environment, for example, through the open first end 26 of the heating chamber 18, which is heated as it flows between the wrapper 110 of the aerosol product 100 and the inner surface 36 of the side wall 30. More specifically, when a user inhales over the filter segment, air is drawn into the heating chamber 18 through the open first end 26, as indicated by arrow A in Figure 2. The air that enters the heating chamber 18 flows between the wrapper 110 and the inner surface 36 of the side wall 30, from the open first end 26 to the closed second end 34. As described above, the inwardly extending portion 42a extends a sufficient distance into the heating chamber 18 to contact at least the outer surface of the aerosol product 100, typically causing at least some compression of the aerosol product 100. As a result, no voids are present around the entire circumference of the heating chamber 18. Instead, air passages exist in the circumferential regions (four equally spaced gap regions) between the inwardly extending portions 42a, along which air flows from the open first end 26 of the heating chamber 18 toward the closed second end 34. In some examples, there may be more or fewer than four inwardly extending portions 42a and a corresponding number of air passages formed by the gap regions between the inwardly extending portions 42a. When the air reaches the closed second end 34 of the heating chamber 18, it changes direction by approximately 180° and enters the distal end 106 of the aerosol product 100. The air, along with the generated vapor, is then drawn through the aerosol product 100 from the distal end 106 toward the proximal (mouth) end 104, as indicated by arrow B in Figure 2.

[0056] 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 for vaporization into suitable vapor remain in the aerosol generating substrate 102. The controller 24 can adjust the magnitude of the alternating current flowing through the induction coil 48 to ensure that the temperature of the induction-heatable susceptor 42, and therefore 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 to be avoided.

[0057] To support this, the controller 24 receives a temperature reading of the aerosol-generating substrate 102, more specifically the inductively heatable susceptor 42, from the temperature sensor 60, and is configured to use this temperature reading to control the magnitude of the alternating current supplied to the induction coil 48. In one example, 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. Subsequently, 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. Subsequently, the controller 24 may supply an alternating current of a third magnitude to the induction coil 48 for a third period to heat the inductively heatable susceptor 42 again to the first temperature. This may continue until the aerosol generating substrate 102 is exhausted (i.e., all the vapor that can be generated by heating has already been produced) or until the user stops using the aerosol generating device 10. In another scenario, once the first temperature is reached, the controller 24 may reduce the magnitude of the alternating current supplied to the induction coil 48 in order to maintain the aerosol generating substrate 102 at the first temperature throughout the session.

[0058] A single inhalation by a user is generally referred to as a "puff." In some scenarios, it is desirable to mimic the experience of smoking a cigarette. This means that the aerosol generating device 10 is capable of holding enough aerosol generating substrate 102 to provide typically 10 to 15 puffs.

[0059] In some embodiments, the controller 24 is configured to count puffs and interrupt the supply of current to the induction coil 48 after the user has performed 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. This is due to the cooling of the susceptor 42 as fresh, cold air flows through the inductively heatable susceptor 42, which is detected by the temperature sensor 60. In other embodiments, the airflow is detected directly using a flow detector. Other preferred methods will be apparent to those skilled in the art. In other embodiments, in addition or instead, the controller 24 interrupts the supply of current to the induction coil 48 after a predetermined time has elapsed since the first puff. This can serve both to reduce power consumption and to provide a backup for switching off the aerosol generating device 10 if the puff counter fails to correctly register that a predetermined number of puffs have been performed.

[0060] In some examples, 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 stops supplying current to the induction coil 48. In some cases, this cycle may utilize a feedback loop between the controller 24 and the temperature sensor 60. For example, the heating cycle may be parameterized by a series of temperatures to which the inductively heatable susceptor 42 may be heated or cooled. The temperature and duration of such a heating cycle can be empirically determined to optimize the temperature of the aerosol-generating substrate 102. This may be necessary, for example, where the outer layer of the substrate is at a different temperature from the core, as direct measurement of the temperature of the aerosol-generating substrate 102 may be impractical or misleading.

[0061] The power supply 22 is sufficient to raise the aerosol-generating substrate 102 in a single aerosol product 100 to a maximum first temperature, maintain the substrate at the first temperature, and supply enough vapor for at least 10 to 15 puffs. More generally, in line with the imitation of the smoking experience, the power supply 22 is usually sufficient to repeat this cycle (raising the aerosol-generating substrate 102 to the first temperature and maintaining the first temperature and vapor generation for 10 to 15 puffs) 10 or even 20 times, thereby imiting the user experience of smoking a cigarette package before the power supply 22 needs to be replaced or recharged.

[0062] Generally, the efficiency of the aerosol generating device 10 is improved when as much heat as possible generated by the inductively heatable susceptor 42 leads to the heating of 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 flow to other parts of the aerosol generating device 10. In particular, heat flow to the parts of the aerosol generating device 10 that the user holds is kept to a minimum, thereby keeping these parts cool and comfortable to grip.

[0063] While exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications to these embodiments are possible 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.

[0064] 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.

[0065] 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. An induction heating assembly (11) for an aerosol generating device (10), A heating chamber (18) having a chamber wall (30) that defines the internal volume (20) of the heating chamber (18) and an opening (26) for receiving an aerosol generating substrate (102), An induction coil (48) for generating an electromagnetic field, An inductively heatable susceptor (42) arranged along the inner surface (36) of the chamber wall (30), comprising: a first portion (54) positioned relative to the induction coil (48) so as to be inductively heated by the electromagnetic field; and a second portion (56) positioned closer to the opening (26) than the first portion (54) so ​​as not to be inductively heated by the electromagnetic field, wherein the first portion (54) and the second portion (56) comprise the same susceptor material, A temperature sensor (60) that contacts the second portion (56) of the induction-heatable susceptor (42) and An induction heating assembly (11) including the above.

2. The induction heating assembly according to claim 1, wherein the first portion (54) of the induction-heatable susceptor (42) is surrounded by the induction coil (48), and the second portion (56) of the induction-heatable susceptor (42) is located outside the induction coil (48).

3. The induction heating assembly according to claim 1 or 2, wherein the induction coil (48) extends around the heating chamber (18).

4. The induction heating assembly according to claim 3, wherein the first portion (54) of the induction-heatable susceptor (42) is located inside the heating chamber (18), and the second portion (56) of the induction-heatable susceptor (42) is located outside the heating chamber (18).

5. The induction heating assembly according to claim 4, wherein the heating chamber (18) has a longitudinal axis defining its longitudinal direction, the induction heating susceptor (42) is elongated in the longitudinal direction of the heating chamber (18), and the second portion (56) of the induction heating susceptor (42) protrudes from the end of the heating chamber (18).

6. The induction heating assembly according to any one of claims 3 to 5, wherein the plurality of induction-heatable susceptors (42) are spaced apart around the inner surface (36) of the chamber wall (30), and the induction heating assembly (11) includes a plurality of temperature sensors (60), the plurality of temperature sensors (60) being arranged such that the second portion (56) of each induction-heatable susceptor (42) is in contact with the corresponding temperature sensor (60).

7. The induction heating assembly according to claim 6, wherein the chamber wall (30) includes a plurality of susceptor mounts (40) formed in or on the inner surface (36) for mounting the plurality of induction-heatable susceptors (42).

8. The induction heating assembly according to claim 6 or 7, wherein the chamber wall (30) includes a coil support structure (50) formed in or on the outer surface (38) for supporting the induction coil (48).

9. The induction heating assembly according to claim 8, wherein the coil support structure (50) includes a coil support groove (52) that extends spirally around the outer surface (38) of the chamber wall (30).

10. The induction heating assembly according to any one of claims 6 to 9, wherein the heating chamber (18) is substantially tubular, and the induction-heatable susceptor (42) is spaced apart around the periphery (44) of the substantially tubular heating chamber (18).

11. The induction heating assembly according to any one of claims 3 to 10, wherein the heating chamber (18) comprises a substantially non-conductive and non-magnetic material.

12. The induction heating assembly according to claim 11, wherein the heating chamber (18) comprises a heat-resistant plastic material.

13. The induction heating assembly according to any one of claims 1 to 12, wherein the temperature sensor (60) is selected from the group consisting of thermocouples and thermistors.

14. Aerosol generating device (10), An induction heating assembly (11) according to any one of claims 1 to 13, A power supply (22) is arranged to supply power to the induction coil (48) and an aerosol generating device (10) including the aerosol generating device.

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