Aerosol generating device and aerosol generating system

Abstract

The aerosol generating device (10) includes a controller (24) and an induction heating device (46) configured to heat an aerosol-generating substrate (102) to generate an aerosol to be inhaled. The induction heating device (46) includes an induction coil (48) including at least a plurality of first coil strands (62) and a plurality of second coil strands (64), and the controller (24) is configured to control the induction heating device (46) to supply alternating current to the plurality of first coil strands (62) to generate a first electromagnetic field having a first frequency, and to supply alternating current to the plurality of second coil strands (64) to generate a second electromagnetic field having a second frequency different from the first frequency. An aerosol generating system 1 including the aerosol generating device (10) and the aerosol-generating substrate (102) is also described.

Description

[Technical field]

[0001] The present disclosure generally relates to an aerosol generating device, and more particularly to an aerosol generating device 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 including an aerosol generating device and an aerosol-generating substrate, and a method of using the aerosol generating system to generate an aerosol to be inhaled. 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, rather than combustion, to generate an aerosol for inhalation by a user. The present disclosure particularly relates to an inductively heated aerosol generating device and / or system. [Background technology]

[0002] In recent years, the popularity and use of risk-reducing or risk-modifying devices (also known as aerosol-generating devices, or vapor-generating devices, or personal vaporizers) has grown rapidly as an alternative to the use of traditional tobacco products. A variety of devices and systems are available that heat or warm an aerosol-generating material to generate an aerosol for inhalation by the user.

[0003] A commonly available risk reduction or risk modification device is the substrate heated aerosol generating device, i.e. the so-called non-combustion heated device. This type of device generates an aerosol or vapour by heating an aerosol-generating substrate, typically to a temperature in the range of 150° C. to 300° C. Heating the aerosol-generating substrate to a temperature within this range, without burning or combusting the aerosol-generating substrate, generates a vapour which typically cools and condenses to form an aerosol which is inhaled by a user of the device.

[0004] Currently available aerosol-generating devices can provide heat to the aerosol-generating substrate using one of several different techniques. One such technique is to provide an aerosol-generating device that employs an induction heating system. In such devices, an induction coil is provided within the device and an inductively heatable susceptor is provided to heat the aerosol-generating substrate. When a user activates the device, electrical energy is provided to the induction coil, which in turn generates an alternating electromagnetic field. The susceptor couples with the electromagnetic field to generate heat, which is transferred to the aerosol-generating substrate, for example, by one or more of conduction, radiation, and convection, and aerosol is generated as the aerosol-generating substrate heats up. Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, it is desirable to control the heat distribution within the aerosol-generating substrate to ensure that an aerosol is generated with acceptable characteristics for inhalation by a user throughout a period of use (also known as a smoking session). It is an aim of embodiments of the present disclosure to provide an improved user experience in which the characteristics of the generated aerosol are optimized by more precise control of the heat distribution within the aerosol-generating substrate. [Means for solving the problem]

[0006] According to a first aspect of the present disclosure, there is provided an aerosol generating device comprising: A controller; an induction heating device configured to heat the aerosol-generating substrate to generate an aerosol to be inhaled, the induction heating device including an induction coil including at least a plurality of first coil strands and a plurality of second coil strands; An aerosol generating device is provided, in which a controller is configured to control the induction heating apparatus to supply alternating current to a plurality of first coil strands to generate a first electromagnetic field having a first frequency, and to supply alternating current to a plurality of second coil strands to generate a second electromagnetic field having a second frequency different from the first frequency.

[0007] The aerosol-generating device is configured to heat the aerosol-generating substrate without burning the aerosol-generating substrate to volatilize at least one component of the aerosol-generating substrate, thereby generating a heated vapor that cools and condenses to form an aerosol for inhalation by a user of the aerosol-generating device. The aerosol-generating device is typically a handheld, portable device.

[0008] Generally speaking, a vapor is a substance that is in the gas phase below its critical temperature, meaning that it can be condensed into a liquid by increasing the pressure without decreasing the temperature, while an aerosol is fine solid particles or liquid 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 with respect to the form of inhalable medium that is generated for a user to inhale.

[0009] By generating first and second electromagnetic fields having different first and second frequencies, the present disclosure allows for careful control of the heat distribution within the aerosol-generating substrate, for example because the first electromagnetic field can cause preferential heating of a first inductively heatable susceptor and the second electromagnetic field can cause preferential heating of a second inductively heatable susceptor. Thus, selective (or "zonal") heating of the aerosol-generating substrate can be achieved. The use of a single induction coil including multiple first coil strands for generating the first electromagnetic field and multiple second coil strands for generating the second electromagnetic field provides an effective solution for generating the first and second electromagnetic fields and ensures that the aerosol-generating device has a compact design.

[0010] We now describe optional features, which may be applied alone or in any combination with any aspect of the present disclosure.

[0011] The induction coil may include a first coil portion in which the plurality of first coil strands may be disposed, and a second coil portion in which the plurality of second coil strands may be disposed. The induction coil may include a periphery defining a cross-sectional coil envelope, and the first and second coil portions may be disposed within the cross-sectional coil envelope. Providing the first and second coil portions ensures that the plurality of first coil strands and the plurality of second coil strands are separated from one another within the cross-sectional coil envelope.

[0012] The induction coil can include an outer insulator that can surround both the first and second coil portions and define a coil periphery.

[0013] The induction coil has a first end and a second end, and both the first coil strand and the second coil strand can extend from the first end to the second end.

[0014] The first and second coil portions may be electrically insulated from one another to ensure that there is no electrical contact between the plurality of first coil strands of the first coil portion and the plurality of second coil strands of the second coil portion.

[0015] The plurality of first coil strands can have a first cross-section and the plurality of second coil strands can have a second cross-section that can differ from the first cross-section. The different first and second cross-sections facilitate generation of first and second electromagnetic fields having different first and second frequencies. For example, the plurality of first coil strands and the plurality of second coil strands can differ from one another in one or more of a cross-sectional shape and a cross-sectional area.

[0016] The alternating current supplied to the first coil strand may include a first alternating current, and the alternating current supplied to the second coil strand may include a second alternating current. The first alternating current may be different from the second alternating current. The first coil strand may be the same as the second coil strand (e.g., in cross-section, diameter, and material). Alternatively, the first coil strand may be different from the second coil strand (e.g., in cross-section, diameter, and / or material, as discussed above).

[0017] The controller may be configured to sequentially supply alternating current to the plurality of first coil strands and the plurality of second coil strands to sequentially generate the first and second electromagnetic fields. Thus, the first and second electromagnetic fields are not generated simultaneously, but at different times. This allows different regions or parts of the aerosol-generating substrate to be heated sequentially, advantageously allowing for control of the heat distribution within the aerosol-generating substrate, in particular selective (or "zonal") heating.

[0018] The controller may be configured to supply a (first) alternating current to a plurality of first coil strands for a first time period to generate a first electromagnetic field for the first time period, and thereafter supply a (second) alternating current to a plurality of second coil strands for a second time period following the first time period to generate a second electromagnetic field for the second time period. The first electromagnetic field may cause preferential heating of the first inductively heatable susceptor during the first time period, and the second electromagnetic field may cause preferential heating of the second inductively heatable susceptor during the second time period. Thus, the first inductively heatable susceptor may be heated to a higher temperature than the second inductively heatable susceptor during the first time period, while the second inductively heatable susceptor may be heated to a higher temperature than the first inductively heatable susceptor during the second time period. This also provides for controlled heat distribution within the aerosol-generating substrate, and in particular provides for selective (or "zonal") heating.

[0019] The aerosol-generating device may include a heating chamber that may define a heating zone for receiving at least a portion of the aerosol-generating substrate. An induction coil may be disposed adjacent to the heating chamber for generating first and second electromagnetic fields within the heating zone. Thus, the aerosol-generating substrate may be efficiently heated when disposed in the heating zone defined by the heating chamber.

[0020] The first electromagnetic field may be adapted to heat a first inductively heatable susceptor having a first resonant frequency, and the second electromagnetic field may be adapted to heat a second inductively heatable susceptor having a second resonant frequency different from the first resonant frequency. Thus, the first electromagnetic field causes preferential heating of the first inductively heatable susceptor, and the second electromagnetic field causes preferential heating of the second inductively heatable susceptor. By using different resonant frequencies, selective (or "zonal") heating of the aerosol-generating substrate can be achieved.

[0021] The use of different resonant frequencies allows selective (or "zonal") heating of the aerosol-generating substrate to be performed by controlling the induction heating device such that the first coil strands generate a first electromagnetic field having a first frequency substantially equal to the first resonant frequency of the first inductively heatable susceptor, and the second coil strands generate a second electromagnetic field having a second frequency substantially equal to the second resonant frequency of the second inductively heatable susceptor. Generating an electromagnetic field (first or second electromagnetic field) having a frequency (first or second frequency) substantially equal to the resonant frequency (first or second resonant frequency) of a particular susceptor (first or second susceptor) generates an amount of heat in that susceptor. This may also cause one or more of the other susceptors (i.e., susceptors having a resonant frequency that is not substantially equal to the frequency of the generated electromagnetic field) to generate an amount of heat that is typically less than the amount of heat generated by the particular susceptor, and may be zero or substantially zero. Thus, any selective heating of a particular susceptor should not be construed to mean that other susceptors are not heated at all, and selective heating of a particular susceptor usually only means that it is primarily responsible for the emission of aerosol from the aerosol-generating substrate adjacent to the particular susceptor. The term "preferential heating" is used throughout this specification to define this type of heating.

[0022] The aerosol-generating device includes a first inductively heatable susceptor and a second inductively heatable susceptor. The first and second inductively heatable susceptors provide rapid and controlled heating of the aerosol-generating substrate while simultaneously maximizing energy efficiency. By providing the first and second inductively heatable susceptors as part of the aerosol-generating device, rather than providing the aerosol-generating substrate as part of the aerosol-generating article, construction and manufacture of the aerosol-generating article can be simplified.

[0023] The first and second inductively heatable susceptors may be disposed around the heating chamber within the heating zone to define a first region within the heating zone and a second region within the heating zone, respectively. The induction coil may extend helically around the heating chamber. Thus, selective (or "zonal") heating of the aerosol-generating substrate may be achieved in the first and second regions. For example, a first portion of the aerosol-generating substrate may be disposed in the first region and heated in the first region by the first inductively heatable susceptor, and a second portion of the aerosol-generating substrate may be disposed in the second region and heated in the second region by the second inductively heatable susceptor. By providing an induction coil that extends helically around the heating chamber, reliable heating of the first and second inductively heatable susceptors by the corresponding first and second electromagnetic fields may be ensured.

[0024] The induction coil may comprise Litz wire or Litz cable, however, it should be understood that other materials may also be used.

[0025] The induction coil may be arranged, in use, to operate with a varying electromagnetic field having a magnetic flux density of about 20 mT to about 2.0 T (at the point of highest density).

[0026] The heating chamber may be substantially tubular, and the first and second inductively heatable susceptors may be spaced apart about a periphery of the substantially tubular heating chamber. The heating chamber may be substantially cylindrical, and the first and second inductively heatable susceptors may be spaced apart circumferentially about the substantially cylindrical heating chamber. Thus, the heating chamber may be configured to receive a substantially cylindrical aerosol-generating substrate, which may be advantageous because aerosol-generating substrates in the form of aerosol-generating articles are often packaged and sold in a cylindrical shape.

[0027] The heating chamber may have a longitudinal axis defining a longitudinal direction. Each of the first and second inductively heatable susceptors may be elongated in the longitudinal direction of the heating chamber. Each of the first and second inductively heatable susceptors may have a length and a width, and in one embodiment, the length may be at least five times the width. The elongated first and second inductively heatable susceptors heat efficiently in the presence of the first and second electromagnetic fields, and their elongated shape ensures that the aerosol-generating substrate is heated quickly and uniformly along its length, thereby maximizing the energy efficiency of the aerosol-generating device.

[0028] The heating chamber may comprise a substantially electrically non-conductive and non-magnetically permeable material. For example, the heating chamber may comprise a heat-resistant plastic material such as polyetheretherketone (PEEK). During operation of the aerosol generating device, the heating chamber itself is not heated by the induction heating apparatus, allowing the energy input to the first and second inductively heatable susceptors to be maximized. This therefore ensures maximum energy efficiency of the device. The device also remains cool to the touch, ensuring maximum user comfort.

[0029] The first and second inductively heatable susceptors may comprise a metal. The metal is typically selected from the group consisting of stainless steel and carbon steel. However, the first and second inductively heatable susceptors may comprise any suitable material, including, but not limited to, one or more of aluminum, iron, nickel, stainless steel, carbon steel, and alloys thereof, such as nickel-chromium or nickel-copper. Application of a first or second electromagnetic field in the vicinity of the susceptor causes the corresponding first or second inductively heatable susceptor to generate heat due to eddy currents and magnetic hysteresis losses resulting in energy conversion from electromagnetic to heat.

[0030] The aerosol generating device may include a power source and the controller may include a control circuit. The power source and control circuit may be configured to operate at a high frequency. The power source and control circuit may be configured to operate at a frequency of about 80 kHz to 1 MHz, optionally about 150 kHz to 250 kHz, optionally about 200 kHz. The power source and control circuit may be configured to operate at a higher frequency, such as in the MHz range, depending on the type of inductively heatable susceptor used. The power source and control circuit may be configured to operate at multiple frequencies (e.g., at least two frequencies).

[0031] According to a second aspect of the present disclosure, there is provided an aerosol generation system comprising: an aerosol-generating substrate; an aerosol generating device as defined above for heating an aerosol-generating substrate to generate an aerosol to be inhaled; An aerosol generating system is provided that includes:

[0032] The aerosol-generating substrate may comprise any type of solid or semi-solid material. Exemplary types of aerosol-generating solids include, for example, powders, granules, pellets, shreds, strands, particles, gels, strips, loose-leaf, cut filler, porous materials, foamed materials or sheets. The aerosol-generating substrate may comprise a plant-derived material, in particular tobacco. The aerosol-generating substrate may advantageously comprise reconstituted tobacco, for example tobacco with cellulose fibres, tobacco stem fibres and inorganic fillers (CaCO 3 and any one or more of the following:

[0033] Thus, aerosol-generating devices may be referred to as "heated tobacco devices," "heated non-combustion tobacco devices," "devices for vaporizing tobacco products," etc., and are to be construed as devices suitable for achieving these effects. The features disclosed herein are equally applicable to devices designed to vaporize any aerosol-generating substrate.

[0034] The aerosol-generating substrate may form part of the aerosol-generating article and may be surrounded by a paper wrapper.

[0035] The aerosol-generating article may be substantially formed in the shape of a stick and may generally resemble a cigarette with a tubular region having the aerosol-generating substrate arranged 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. Some designs may also include one or more vapor collection regions, cooling regions, and other structures. 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 allow the heated vapor generated by heating the aerosol-generating substrate to cool and condense to form an aerosol having suitable properties for inhalation by a user, for example through the filter segment.

[0036] The aerosol-generating substrate may include 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 include an aerosol-forming agent content of about 5% to about 50% on a dry weight basis. In some embodiments, the aerosol-generating substrate may include an aerosol-forming agent content of about 10% to about 20% on a dry weight basis, and in some cases about 15% on a dry weight basis.

[0037] When heated by the first or second inductively heatable susceptors, the aerosol-generating substrate may emit volatile compounds, which may include flavor compounds such as nicotine or tobacco flavorings.

[0038] According to a third aspect of the present disclosure, there is provided a method of using an aerosol generating system as defined above, comprising the steps of: placing at least a portion of an aerosol-generating substrate within a heating chamber of an aerosol-generating device; operating the induction heating device by the controller to supply alternating current to the first plurality of coil strands for a first time period to generate a first electromagnetic field for a first time period to heat a first portion of the aerosol-generating substrate; operating, by the controller, the induction heating device to supply alternating current to the second plurality of coil strands for a second time period subsequent to the first time period to generate a second electromagnetic field for the second time period to heat a second portion of the aerosol-generating substrate; A method is provided that includes:

[0039] The first electromagnetic field can cause preferential heating of the first inductively heatable susceptor during a first time period, and the second electromagnetic field can cause preferential heating of the second inductively heatable susceptor during a second time period. Thus, the first inductively heatable susceptor can be heated to a higher temperature than the second inductively heatable susceptor during a first time period, while the second inductively heatable susceptor can be heated to a higher temperature than the first inductively heatable susceptor during a second time period. As noted above, this provides for controlled heat distribution within the aerosol-generating substrate, and in particular for selective (or "zonal") heating.

[0040] In one embodiment of the method, the heating chamber may define a heating zone.

[0041] Operating the induction heating device by the controller to supply alternating current to the first plurality of coiled strands can cause the generated first electromagnetic field to heat a first inductively heatable susceptor defining a first region of the heating zone in which a first portion of the aerosol-generating substrate is disposed, and operating the induction heating device by the controller to supply alternating current to the second plurality of coiled strands can cause the generated second electromagnetic field to heat a second inductively heatable susceptor defining a second region of the heating zone in which a second portion of the aerosol-generating substrate is disposed.

[0042] The method thus provides selective (or "zonal") heating of the aerosol-generating substrate in first and second regions. In particular, a first portion of the aerosol-generating substrate located in the first region is heated by a first inductively heatable susceptor, and a second portion of the aerosol-generating substrate located in the second region is heated by a second inductively heatable susceptor. As noted above, the heating of the first and second portions of the aerosol-generating substrate is typically sequential. [Brief description of the drawings]

[0043] [Figure 1] 1 is a schematic cross-sectional view of an aerosol generating system including an aerosol generating device and an aerosol-generating article about to be placed in a heating chamber of the aerosol generating device. FIG. [Diagram 2] 2 is a schematic cross-sectional view of the aerosol generating system of FIG. 1, showing an aerosol-generating article disposed within a heating chamber of the aerosol generating device. [Diagram 3] FIG. 3 is a detailed schematic perspective view of the heating chamber of the aerosol generating device of FIGS. 1 and 2, showing first and second inductively heatable susceptors attached to the inner surface of the heating chamber. [Figure 4] 4 is a schematic cross-sectional end view of the heating chamber shown in FIG. 3 showing first and second inductively heatable susceptors spaced apart about the periphery of the heating chamber; FIG. [Diagram 5]FIG. 2 is a schematic perspective view of an induction coil of an aerosol generating device, showing first and second coil portions within a cross-sectional coil housing of the induction coil. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0045] 1 and 2, an example of an aerosol generating system 1 is shown generally. The aerosol generating system 1 includes an aerosol generating device 10 and an aerosol generating article 100 for use with the device 10. The aerosol generating device 10 includes a body 12 that houses the various components of the aerosol generating device 10. The body 12 can have any shape that is sized to fit the components described in the various embodiments presented herein and to be comfortably held by a user in one hand without assistance.

[0046] A first end 14 of the aerosol generating device 10, shown at the bottom in Figures 1 and 2, is for convenience described as the distal, bottom, base or lower end of the aerosol generating device 10. A second end 16 of the aerosol generating device 10, shown at the top in Figures 1 and 2, is described as the proximal, top or upper end of the aerosol generating device 10. During use, a user typically orients the aerosol generating device 10 with the first end 14 facing downward and / or in a distal position relative to the user's mouth and the second end 16 facing upward and / or in a proximal position relative to the user's mouth.

[0047] The aerosol generating device 10 includes a heating chamber 18 disposed within the body 12. The heating chamber 18 defines a heating zone 19 within an interior volume in the form of a cavity 20 having a substantially cylindrical cross-section for receiving the aerosol generating article 100. The heating chamber 18 has a longitudinal axis defining a lengthwise 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 (e.g., one or more batteries, which may be rechargeable) and a controller 24.

[0048] The heating chamber 18 is open towards 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 towards the second end 16 of the aerosol generating device 10. The heating chamber 18 is typically spaced apart from the inner surface of the body 12 to minimize heat transfer to the body 12.

[0049] The aerosol generating device 10 may optionally include a sliding cover 28 that is laterally movable between a closed position (see FIG. 1 ) that covers the open first end 26 of the heating chamber 18 to prevent access to the heating chamber 18, and an open position (see FIG. 2 ) that exposes the open first end 26 of the heating chamber 18 to provide access to the heating chamber 18. In some embodiments, the sliding cover 28 may be biased to the closed position.

[0050] The heating chamber 18, and more specifically the cavity 20, is configured to receive a correspondingly shaped, generally cylindrical or rod-shaped aerosol-generating article 100. Typically, the aerosol-generating article 100 includes a pre-packaged aerosol-generating substrate 102. The aerosol-generating article 100 is a disposable and replaceable article (also known as a "consumable") that may include, for example, tobacco 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 includes a mouthpiece segment 108 disposed downstream of the aerosol-generating substrate 102. The aerosol-generating substrate 102 and the mouthpiece segment 108 are disposed in coaxial alignment within a wrapper 110 (e.g., a paper wrapper) to hold the components in place and form the rod-shaped aerosol-generating article 100.

[0051] The mouthpiece segment 108 may include one or more of the following components (not shown in detail) arranged sequentially and in coaxial alignment in a downstream direction, i.e., from the distal end 106 toward 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 includes a hollow paper tube having a thickness greater than that of the wrapper 110. The central hole segment may include a hardened mixture containing cellulose acetate fibers and a plasticizer, and 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-generating article 100, the vapor cools and condenses as it passes through the cooling segment and the central hole segment to form an aerosol having suitable properties for a user to inhale through the filter segment.

[0052] 3 and 4, the heating chamber 18 has a sidewall (or chamber wall) 30 that extends between a base 32 located at a second end 34 of the heating chamber 18 and the open first end 26. The sidewall 30 and the base 32 may be connected together and integrally formed as a single piece. In the illustrated embodiment, the sidewall 30 is tubular, more specifically cylindrical. In other embodiments, the sidewall 30 may be of other suitable shapes, such as tubular with an elliptical or polygonal cross section. In yet other embodiments, the sidewall 30 may be tapered.

[0053] In the illustrated embodiment, the base 32 of the heating chamber 18 is closed, e.g., sealed or airtight; i.e., the heating chamber 18 is cup-shaped. This ensures that the base 32 prevents air drawn in from the open first end 26 from exiting the second end 34, but is instead directed through the aerosol-generating substrate 102. This also ensures that a user inserts the aerosol-generating article 100 into the heating chamber 18 the intended distance and no further.

[0054] The sidewall 30 of the heating chamber 18 has an inner surface 36 and an outer surface 38. The aerosol generating device 10 includes first and second inductively heatable susceptors 40, 42 mounted on the inner surface 36 of the sidewall 30 within the heating zone 19. In the illustrated example, each of the first and second inductively heatable susceptors 40, 42 is circumscribed at an angle of less than 180°, such that together the first and second inductively heatable susceptors 40, 42 extend circumferentially around substantially the entire circumference of the inner surface 36 of the sidewall 30. The first inductively heatable susceptor 40 defines a first region 41 for heating within the heating zone 19, and the second inductively heatable susceptor 42 defines a second region 43 for heating within the heating zone 19.

[0055] The first and second inductively heatable susceptors 40, 42 extend longitudinally through the heating chamber 18. Each of the first and second inductively heatable susceptors 40, 42 has a length and a width, and typically the length is at least five times the width. Those skilled in the art will appreciate that the first and second inductively heatable susceptors 40, 42 are not limited to the dimensions shown in Figures 3 and 4, and other dimensions are fully within the scope of the present disclosure.

[0056] The first and second inductively heatable susceptors 40, 42 have inner surfaces 40a, 42a, respectively, that are in contact with the aerosol-generating substrate 102. The first and second inductively heatable susceptors 40, 42 can form frictional engagement with the aerosol-generating substrate 102, more specifically the wrapper 110 of the aerosol-generating article 100, causing compression of the aerosol-generating substrate 102, as best shown in Figure 2. Compression of the aerosol-generating substrate 102 improves heat transfer through the aerosol-generating substrate 102, for example, by eliminating voids within the aerosol-generating substrate 102.

[0057] The aerosol generating device 10 includes an induction heating apparatus 46 for heating the aerosol-generating substrate 102. The induction heating apparatus 46 includes a substantially helical induction coil 48. The induction coil 48 extends helically around the substantially cylindrical heating chamber 18. The induction coil 48 may be energized by a power source 22 and a controller 24. The controller 24 includes, among other electronic components, an inverter arranged to convert direct current from the power source 22 to alternating high frequency current for the induction coil 48.

[0058] The sidewall 30 of the heating chamber 18 includes a coil support structure 50 formed in the outer surface 38. In the illustrated example, the coil support structure 50 includes a coil support groove 52 that extends helically around the outer surface 38. The induction coil 48 is disposed within the coil support groove 52 and is thus securely and optimally positioned relative to the first and second inductively heatable susceptors 40, 42.

[0059] 5, the induction coil 48 includes a coil periphery 54 in cross section, which defines a cross-sectional coil jacket 56. An outer insulator (not shown) may surround the coil periphery 54. Within the cross-sectional coil jacket 56 is a first coil portion 58 and a second coil portion 60 electrically insulated from the first coil portion 58. The first coil portion 58 includes a plurality of first coil strands 62, and the second coil portion 60 includes a plurality of second coil strands 64. In the illustrated example, the first coil strand 62 has a first cross-sectional area and the second coil strand 64 has a second cross-sectional area that is larger than the first cross-sectional area. However, this configuration is not required and it may be sufficient for the first coil strand 62 to have a first cross-sectional area and the second coil strand 64 to have a second cross-sectional area that is different from the first cross-sectional area. Here, the term "cross-section" may include one or more of a cross-sectional area and a cross-sectional shape. It should also be noted that the first and second coil portions 58, 60 do not have to be semi-circular as shown in Figure 5, and other configurations are possible, such as a concentric configuration of the first and second coil portions 58, 60.

[0060] To use the aerosol generating device 10, a user moves the sliding 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 into the heating chamber 18 through the open first end 26 such that the aerosol-generating substrate 102 is received within the heating zone 19 defined by the cavity 20 and the proximal end 104 of the aerosol-generating article 100 is positioned in 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.

[0061] When a user activates the aerosol generating device 10, the induction heating device 46 is energized by the power source 22 and the controller 24. More specifically, according to the present disclosure, the controller 24 is configured to control the induction heating device 46, more specifically the power source 22 and the control circuitry, to supply alternating current to the plurality of first coil strands 62 of the first coil portion 58 to generate a first electromagnetic field having a first frequency, and to supply alternating current to the plurality of second coil strands 64 of the second coil portion 60 to generate a second electromagnetic field having a second frequency.

[0062] The first and second inductively heatable susceptors 40, 42 have different resonant frequencies. A first electromagnetic field having a first frequency causes preferential heating of the first inductively heatable susceptor 40 (by eddy currents and / or magnetic hysteresis losses generated in the first inductively heatable susceptor 40) and therefore causes preferential heating of a first portion of the aerosol-generating substrate 102 located in a first region 41 of the heating zone 19 by heat transferred from the first inductively heatable susceptor 40. A second electromagnetic field having a second frequency causes preferential heating of the second inductively heatable susceptor 42 (by eddy currents and / or magnetic hysteresis losses generated in the second inductively heatable susceptor 42) and therefore causes preferential heating of a second portion of the aerosol-generating substrate 102 located in a second region 43 of the heating zone 19 by heat transferred from the second inductively heatable susceptor 42. Thus, selective (or "zonal") heating of first and second portions of the aerosol-generating substrate 102 is achieved in first and second regions 41, 43 within the heating zone 19. Heating of the aerosol-generating substrate 102 by the first or second inductively heatable susceptor 40, 42 results in heating of the aerosol-generating substrate 102 without burning or combusting, thereby generating vapour. The generated vapour cools and condenses into an aerosol that can be inhaled by a user of the aerosol-generating device 10 through the mouthpiece segment 108 (more specifically the filter segment).

[0063] The controller 24 is typically configured to supply alternating current to the plurality of first coil strands 62 in the first coil portion 58 for a first time period to generate a first electromagnetic field (having a first frequency) for the first time period. Thereafter, the controller 24 is typically configured to supply alternating current to the plurality of second coil strands 64 in the second coil portion 60 for a second time period to generate a second electromagnetic field (having a second frequency) for the second time period. Thus, because the supply of alternating current to the plurality of first coil strands 62 and the plurality of second coil strands 64 is sequential rather than simultaneous, the generation of the first and second electromagnetic fields (having their corresponding first and second frequencies) is also sequential. Thus, during the first time period, the first inductively heatable susceptor 40 is preferentially heated by the first electromagnetic field, and during the second time period, the second inductively heatable susceptor 42 is preferentially heated by the second electromagnetic field. This provides sequential, and therefore selective (or “zonal”) heating of first and second portions of the aerosol-generating substrate 102 located in first and second regions 41, 43, respectively, within the heating zone 19.

[0064] Vaporization of the aerosol-generating substrate 102 is facilitated by the addition of 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 and the inner surface 36 of the sidewall 30 of the aerosol-generating article 100, which has a circumferential gap between the longitudinal edges of the first and second inductively heatable susceptors 40, 42. More specifically, when a user inhales on the filter segment, air is drawn into the heating chamber 18 through the open first end 26, as shown by arrow A in FIG. 2. The air entering the heating chamber 18 flows between the wrapper 110 and the inner surface 36 of the sidewall 30 from the open first end 26 toward the closed second end 34. As mentioned above, the inner surfaces 40a, 42a of the first and second inductively heatable susceptors 40, 42 can contact the outer surface of the aerosol-generating article 100, typically causing at least some compression of the aerosol-generating substrate 102. As a result, there is no air gap circumferentially around the heating chamber 18. Instead, there are air passages 66 in the circumferential regions (two gap regions) between the longitudinal edges of the first and second inductively heatable susceptors 40, 42 along which air flows from the open first end 26 to the closed second end 34 of the heating chamber 18. In some examples, three or more inductively heatable susceptors 40, 42 can be used, and thus a corresponding number of air passages 66 can be formed by the gap regions between the longitudinal edges of circumferentially adjacent inductively heatable susceptors. When the air reaches the closed second end 34 of the heating chamber 18, it turns approximately 180° and enters the distal end 106 of the aerosol-generating article 100. The air, along with the generated vapor, is then drawn through the aerosol-generating article 100 from the distal end 106 towards the proximal (mouth) end 104, as shown by arrow B in FIG.

[0065] Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications to those embodiments may be made without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments.

[0066] Any combination of the above-described features in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or clearly contradicted by context.

[0067] The present invention has been described with reference to examples in which the cross-sectional area of ​​the first coil strand is different from the second coil strand. However, it will be appreciated that the first coil strand may differ from the second coil strand in other respects, if desired. For example, the first coil strand may have a different cross-sectional shape (as well as or instead of a different cross-sectional area) and / or may be formed from a different material than the second coil strand, in order to generate different first and second electromagnetic fields. It will be further appreciated that the first coil strand may be the same as the second coil strand (i.e. have the same cross-section and material), or alternatively, the first coil strand may be energized by the controller with a different alternating current than the second coil strand to generate different first and second electromagnetic fields. In any of these cases, the first coil strand is electrically insulated (e.g. separated by an insulator) from the second coil strand, as described above, to ensure that the coil portions are substantially independently energizable.

[0068] Unless the context clearly dictates otherwise, throughout this specification and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense, i.e., "including but not limited to", rather than in an exclusive or exhaustive sense.

Claims

1. An aerosol generating device (10), comprising: a controller (24); and an induction heating device (46) configured to heat an aerosol generating substrate (102) to generate an inhaled aerosol, the induction heating device (46) including an induction coil (48) including at least a plurality of first coil strands (62) and a plurality of second coil strands (64). The controller (24) is configured to control the induction heating device (46) to supply an alternating current to the plurality of first coil strands (62) to generate a first electromagnetic field having a first frequency, and to supply an alternating current to the plurality of second coil strands (64) to generate a second electromagnetic field having a second frequency different from the first frequency. An aerosol generating device (10).

2. The induction coil (48) includes a first coil portion (58) in which the plurality of first coil strands (62) are arranged, and a second coil portion (60) in which the plurality of second coil strands (64) are arranged. The aerosol generating device according to claim 1.

3. The induction coil (48) includes a peripheral portion (54) defining a cross-sectional coil jacket (56), and the first coil portion (58) and the second coil portion (60) are disposed within the cross-sectional coil jacket (56). The aerosol generating device according to claim 2.

4. The first coil portion (58) and the second coil portion (60) are electrically insulated from each other. The aerosol generating device according to claim 2.

5. The plurality of first coil strands (62) have a first cross-section, and the plurality of second coil strands (64) have a second cross-section different from the first cross-section. The aerosol generating device according to claim 1.

6. The plurality of first coil strands (62) and the plurality of second coil strands (64) are different from each other in one or more of cross-sectional shape and cross-sectional area. The aerosol generating device according to claim 5.

7. The controller (24) is configured to sequentially supply the alternating current to the plurality of first coil strands (62) and the plurality of second coil strands (64) to sequentially generate the first electromagnetic field and the second electromagnetic field. The aerosol generating device according to claim 1.

8. The controller (24) is configured to supply the alternating current to the plurality of first coil strands (62) over a first period to generate the first electromagnetic field over the first period and then supply the alternating current to the plurality of second coil strands (64) over a second period following the first period to generate the second electromagnetic field over the second period, the aerosol generation device according to claim 1.

9. Including a heating chamber (18) defining a heating zone (19) for receiving at least a portion of the aerosol generation substrate (102), and the induction coil (48) is disposed adjacent to the heating chamber (18) to generate the first electromagnetic field and the second electromagnetic field within the heating zone (19), the aerosol generation device according to claim 1.

10. The first electromagnetic field is adapted to heat a first inductively heatable susceptor (40) having a first resonance frequency, and the second electromagnetic field is adapted to heat a second inductively heatable susceptor (42) having a second resonance frequency different from the first resonance frequency, the aerosol generation device according to claim 9.

11. Including the first inductively heatable susceptor (40) and the second inductively heatable susceptor (42), the aerosol generation device according to claim 10.

12. The first inductively heatable susceptor (40) and the second inductively heatable susceptor (42) are disposed around the heating chamber (18) within the heating zone (19) to respectively define a first region (41) within the heating zone (19) and a second region (43) within the heating zone (19), and the induction coil (48) extends spirally around the heating chamber (18), the aerosol generation device according to claim 11.

13. An aerosol generation system (1), An aerosol generation substrate (102), The aerosol generation device (10) according to any one of claims 1 to 12 for heating the aerosol generation substrate (102) to generate an inhaled aerosol, An aerosol generation system (1) comprising.

14. A method of using the aerosol generation system (1) according to claim 13, Placing at least a part of the aerosol generating substrate (102) within the heating chamber (18) of the aerosol generating device (10); Actuating the induction heating device (46) by the controller (24) to supply an alternating current to the plurality of first coil strands (62) over a first period to generate the first electromagnetic field over the first period and heating a first portion of the aerosol generating substrate (102); Actuating the induction heating device (46) by the controller (24) to supply an alternating current to the plurality of second coil strands (64) over a second period following the first period to generate the second electromagnetic field over the second period and heating a second portion of the aerosol generating substrate (102); A method comprising the steps of. [

15. ] The heating chamber (18) defines a heating zone (19), Actuating the induction heating device (46) by the controller (24) to supply the alternating current to the plurality of first coil strands (62) heats a first inductively heatable susceptor (40) defining a first region (41) of the heating zone (19) in which the first portion of the aerosol generating substrate (102) is disposed in the generated first electromagnetic field, and Actuating the induction heating device (46) by the controller (24) to supply the alternating current to the plurality of second coil strands (64) heats a second inductively heatable susceptor (42) defining a second region (43) of the heating zone (19) in which the second portion of the aerosol generating substrate (102) is disposed in the generated second electromagnetic field, the method according to claim 14.

Images