Heater module for an aerosol-generating device with dielectric heater for preheating a formulation

Abstract

The invention provides a heater module (1) for an aerosol-generating device (100) comprising a liquid channel (6), a dielectric heater (2), and an atomizer (3). The liquid channel (6) comprises a first segment (61) and a second segment (62) arranged downstream from the first segment (61). The dielectric heater (2) is arranged at the first segment (61) and configured to dielectrically heat a formulation (7), such as liquid or liquefiable aerosol-generating formulation, when received in the first segment (61) by dipole rotation. The atomizer (3) is arranged at the second segment (62) and configured to aerosolize and / or vaporize the formulation (7) after entering the second segment (62).

Description

[0001] Heater module for an aerosol-generating device with dielectric heater for preheating a formulation

[0002] The present invention relates to a heater module for an aerosol-generating device or an aerosol-generating system, particularly for an electronic cigarette, atomizer or a medical device such as a nebulizer, inhaler or spray to heat a liquid, semi-liquid, or solid aerosol-generating formulation that is thermally liquefiable to adjust its viscosity prior to aerosolization or vaporization.

[0003] Known electronic cigarettes comprise a liquid or oil storage reservoir or replaceable cartridge for storing a liquid formulation (also called e-liquid, vape juice or e-juice), an atomizer for atomizing the liquid formulation, and a battery to power the atomizer. Generally, these devices are handheld, portable, battery-powered, and configured for personal inhalation to be held in a hand of a user. The atomizer can include a vaporizer equipped with a heating element and a liquid transfer element (also called wicking element), which transports the liquid formulation to the heating element via capillary action, gravity, or both. As the liquid formulation reaches the heating element, it is vaporized and subsequently mixed with incoming cool air. This process leads to condensation into tiny liquid droplets, forming an inhalable mist commonly known as aerosol. For medical inhalers and atomizers, aerosol can be formed from a liquid or semi-liquid that is stored in a liquid reservoir and is atomized by mechanical means, e.g. by pressure via a nozzle of a spray, or by a vibrating mesh, or other atomizing means.

[0004] However, for electronic cigarettes, because the liquid transfer element often connects to an air tube of a mouthpiece used for inhalation, liquid from the liquid storage reservoir may leak into the air tube or aerosolization chamber. It has been proposed to increase the viscosity of the liquid formulation to reduce liquid migration through the liquid transfer element to thereby al The aerosol-generating device and / or the aerosol-generating system may be a portable device and / or system. It may be battery powered. Particularly, the aerosol-generating device and / or the aerosolgenerating system may be pocket-size, hand-held, suitable for one-hand use and / or may weigh less than 300 grams, preferably less than 200 grams. It may be shaped and / or sized to fit snugly into a user’s hand. It may be carried in jacket and / or trouser pockets. Particularly, the aerosolgenerating device and / or the aerosol-generating system may be configured to provide aerosol for human inhalation and / or human consumption, particularly inhalation and / or consumption through the mouth. so reduce a flow rate through the liquid transfer element. Liquids that are nearly solid or at least highly viscous at room temperature are known, for example, from EP 3 902 565 B1, EP 3 902 416 B1, EP 3 902 415 B1, EP 4 076 024 A1 , and EP 4 076 025 A1 . However, as a consequence, either user experience is reduced by slow liquid delivery that can lead to dry burn effects, limited aerosol delivery, or both.

[0005] It would be preferable to provide a heater module for an aerosol-generating device, which is capable of delivering a considerable amount of liquid with a desired flow rate to a heater in ashort time, while maintaining sufficient viscosity when stored at room temperature to reduce leakage.

[0006] According to a first aspect of the invention, there is provided a heater module for an aerosolgenerating device comprising a liquid channel, a dielectric heater, and an atomizer. The liquid channel comprises a first segment and a second segment arranged downstream from the first segment. The dielectric heater is arranged at the first segment and configured to dielectrically heat a formulation, such as a liquid or liquefiable aerosol-generating formulation, when received in the first segment by dipole rotation. The atomizer is arranged at the second segment and configured to aerosolize and / or vaporize the formulation after entering the second segment.

[0007] Generally, the atomizer may either heat up the formulation to vaporize it, and the vapor later is mixed with incoming cold air to create an aerosol or directly aerosolize the preheated formulation without heating by means of a mechanical atomizer, for example but not limited to a vibrating mesh or membrane as used in medical nebulizers. So, the mechanical atomizer “aerosolizes”, while a vaporizer “vaporizes”.

[0008] The use of a dielectric heater as a preheater to change viscosity of the aerosol-generating formulation may facilitate liquid transfer and improve subsequent aerosol generation, while preventing leakage when the heater module or the device is off. Vaporization elements for electronic cigarettes have been proposed where for example by two different heating coils or mesh, or two different liquid transfer elements acting as resistive heaters are used for preheating and vaporization respectively. However, a drawback of using resistive heaters is the surface heating of the liquid or semi-liquid formulation, leading to slow and non-uniform heating of the liquid or semi-liquid. Also, this may necessitate the use of complex porous structures with narrow liquid pathways to achieve effective preheating. In addition, the heating efficiency and power delivery to the formulation are limited by the convective heating approach with the resistive heater, and lead to strong temperature decrease of the heated volume when moving away from the resistive heating structures. In contrast, the use of a dielectric heater enabling volumetric heating through dipole rotation may allow for simpler device designs without any obstructions along the liquid flow path, a more efficient and rapid heating, and better heat uniformity. The dielectric heater may, during operation, heat the formulation in the first segment such that a dynamic viscosity of the formulation entering the second segment is lowered to be in an exemplary range of 45 to 1 mPa / s (centipoise cP), preferably 30 to 2 mPa / s (cP), and more specifically 15 to 4 mPa / s (cP).

[0009] The dielectric heater at the first segment may comprise at least two electrodes fed by an alternating high-frequency voltage configured to heat the formulation by an alternating electric field formed by the at least two electrodes in the first segment.

[0010] The dielectric heater arrangement may comprise an oscillation circuit. The oscillation circuit may comprise a switching unit with a feedback loop connected between the input and the output of the switching unit. The feedback loop may comprise one or more inductors and a load capacitorformed by the at least two electrodes. The oscillation circuit may be configured to operate the at least two electrodes at a radio frequency in an ultra-high frequency range (UHF), or in a range from 100 MHz and 5 GHz, preferably between 200 MHz to 2 GHz, and even more preferably from 300 MHz to 1 GHz.

[0011] The oscillation circuit described herein is exemplary only, and other types of oscillation circuits can be used, for example other types of resonant oscillator circuits where the load capacitor for causing the dielectric heating is part of the resonant feedback loop, or signal oscillators that are connected to an amplifier and an impedance matching circuit to apply an RF voltage to the electrodes for causing the alternating electric field for dielectric heating. Forced oscillators or forced oscillation circuits may also be used.

[0012] The at least two electrodes may be plate shaped. The electrode plates may be arranged in parallel with the first segment of the liquid channel arranged therebetween.

[0013] Alternatively, or additionally, the at least two electrodes may comprise one or more pairs of electrodes arranged and / or extending, for example but not limited to in parallel, preferably as parallel strips, bars, or pins, along a longitudinal direction of the first segment.

[0014] The one or more pairs of electrodes, preferably in the form as parallel strips extending along the longitudinal direction, may be arranged to form a cylindrical, oval, or other tubular arrangement, for example to form a flow path inside or outside of the tubular arrangement, or to form a flow path between the individual electrodes.

[0015] The first segment may comprise two channels that are separated from each other. Each channel may have a respective dielectric heater configured to heat the formulation independently. The second segment may be, at least partially, arranged between the two channels. This arrangement may allow for a compact design of the heater module.

[0016] The first segment may define or comprise a sleeve portion extending in a longitudinal direction of the heater module. The second segment may be at least partially formed within the sleeve portion, preferably in a concentric configuration relative to the sleeve portion.

[0017] The second segment may be contiguous to the first segment.

[0018] The one or more of the first segment and the second segment may have a tubular form, such as a cylindrical or oval form.

[0019] A smallest diameter of the second segment may be smaller than a smallest diameter of the first segment.

[0020] The atomizer may include a vaporizer configured to heat the formulation to vaporize the formulation. Particularly, the vaporizer may include a heating element preferably at least one of a resistive heater, an infrared heater, or an inductive heater.

[0021] Alternatively, or additionally, the vaporizer may include a dielectric heater configured to dielectrically heat the formulation in the second segment by dipole rotation.The dielectric heater at the second segment may comprise at least two electrodes configured to heat the formulation by an alternating electric field formed by an alternating voltage applied to the at least two electrodes in the second segment.

[0022] The at least two electrodes at the first segment and the at least two electrodes at the second segment may be electrically insulated from each other.

[0023] In other embodiments, the at least two electrodes at the first segment and the at least two electrodes at the second segment may be mechanically and electrically connected, to form a single capacitor.

[0024] The at least two electrodes at the first segment may define a first electrode arrangement, and the at least two electrodes at the second segment may define a second electrode arrangement that differs from the first electrode arrangement, preferably by one or more of: a shape and a distance between the respective two electrodes of the first and second segments.

[0025] The vaporizer, for example the at least two electrodes at the second segment, may be controlled and / or shaped to provide more heating power than the dielectric heater for preheating. That is because for vaporization at the second segment, more heating power per volume may be usually needed than for the preheating.

[0026] The atomizer may comprise a mechanical atomizer configured to convert the formulation into droplets.

[0027] The mechanical atomizer may comprise a mesh or membrane with a plurality of apertures, and a vibrator, such as a piezoelectric element, configured to vibrate the mesh or the membrane.

[0028] A first channel may form a canister for storing a liquid formulation. The canister may be fluidly connected to a spraying nozzle. The liquid formulation in the interior of the canister may be dielectrically heated up by the dielectric heater before being atomized by the spraying nozzle. A liquid transfer element, such as wicking element, may be at least partially arranged in the second segment. The liquid transfer element may comprise a capillary flow structure to guide movement of the formulation from the first segment to the second segment.

[0029] The liquid transfer element may comprise a porous structure and / or microchannels adapted for capillary transport of the formulation.

[0030] The liquid transfer element may extend into a part of the first segment

[0031] In other variants, the liquid transfer element may not be arranged in the first segment. The heater module may further comprise a temperature sensor configured to measure a temperature of the formulation at the first segment and / or at the second segment, and a controller connected to the dielectric heater and the temperature sensor. The controller may be configured to calculate a value for the viscosity of the formulation based on the measured temperature and to control the dielectric heater based on the calculated viscosity to achieve a pre-defined dynamic viscosity of the formulation in the second segment.The atomizer may be connected to the controller. In the embodiments, the controller may form part of the heater module, or may be an external component such as a component of the aerosol-generating device next to the battery.

[0032] The pre-defined dynamic viscosity may be in a range of 45 to 1 mPa / s (cP), preferably 30 to 2 mPa / s (cP), and more specifically 15 to 4 mPa / s (cP). In the embodiments, the pre-defined dynamic viscosity is in a range of 30 to 1 mPa / s (cP), preferably 20 to 2 mPa / s (cP), and more specifically 10 to 4 mPa / s (cP).

[0033] The temperature sensor may be a thermocouple.

[0034] The controller may be configured to operate the dielectric heater and the atomizer at the same time, to (pre-)heat and aerosolize the formulation simultaneously.

[0035] The controller may be configured to operate the dielectric heater before the atomizer and / or alternately, to heat the formation at a first time instance and to aerosolize the formulation at a second time instance after the first time instance.

[0036] In some embodiments, temperature sensing may be carried out by using a dielectric temperature marker that is in thermal communication with the formulation, to thereby measure one or more temperatures by dielectric response with the heater. The pre-heating to a given temperature of a liquid formation can be especially useful for medical applications.

[0037] In some embodiments, the dielectric heater may be arranged at a distance from the formulation. Heating the formulation without direct contact may prevent potential metal contamination. For example, a protective cover layer of low-dielectric material may be positioned between the dielectric heater and the formulation. This protective cover layer may be made of materials such as Parylene D, Parylene N, polyether ether ketone (PEEK), polyetherimide (PEI), or other low-dielectric, high-temperature-resistant, and low- or non-toxic materials. In some examples, at least a first segment of the liquid channel may be formed from the protective cover layer, for example in the form of a conduit. In particular, this first segment may constitute a housing or canister of a pod or cartridge holder for storing and conveying the formulation, wherein the pod or cartridge is removably received in the aerosol-generating device. Known removable cartridges are described, for example, in WO 2026 / 017916 A1, whose disclosure is herewith incorporated by reference in its entirety. In other examples, the electrodes of the dielectric heater may be at least partially covered or coated with the protective cover layer. According to a second aspect, there may be provided an aerosol-generating device comprising a battery and a heater module according to the first aspect connected to the battery for powering the heater module, in particular the dielectric heater and / or the atomizer thereof.

[0038] According to a third aspect, there may be provided an aerosol-generating system comprising a cartridge holding a formulation, and an aerosol-generating device according to the second aspect configured to aerosolize the formulation.

[0039] The formulation may comprise one or more of liquids, semi-liquids, and solids.The formulation may comprise polypropylene glycol (PPG), vegetable glycerol (VG), Terpenes, Triacetin, PDO (1 ,3-Propanediol), Medium-Chain Triglycerides (MCT) oil or a combination thereof. In embodiments, the formulation may comprise liquids that are nearly solid or at least highly viscous at room temperature, for example but not limited to liquids known from EP 3902565 B1 , EP 3902416 B1, EP 3902415 B1, EP 4076024 A1, and EP 4076025 A1 .

[0040] In an example, the formulation may comprise a nicotine formulation comprising: one or more water-miscible polyhydric alcohols, wherein the nicotine formulation has a water-miscible polyhydric alcohol content of greater than or equal to about 5 percent by weight; and one or more low molar mass metal salts, wherein the one or more low molar mass metal salts are selected from the group consisting of metal cinnamates, metal cycloheptanecarboxylates, metal levulinates, metal propanoates, metal stearates and metal undecanoates.

[0041] In an example, the formulation may comprise a nicotine formulation comprising: one or more water-miscible polyhydric alcohols; and one or more metal salts, and one or more organic acids, wherein the nicotine formulation has a metal salt content of greater than or equal to about 0.5 percent by weight, wherein the one or more metal salts are selected from the group consisting of metal benzoates, metal cinnamates, metal cycloheptanecarboxylates, metal levulinates, metal propanoates, metal stearates and metal undecanoates, and wherein the nicotine formulation has an organic acid content of between about 0.5 percent and about 4 percent by weight.

[0042] In an example, the formulation may comprise a nicotine formulation comprising: one or more water-miscible polyhydric alcohols, wherein the nicotine formulation has a water-miscible polyhydric alcohol content of greater than or equal to about 40 percent by weight, wherein the nicotine formulation is solid at 25°C or has a viscosity at 25°C of greater than or equal to about 100 Pa-s, wherein the one or more water-miscible polyhydric alcohols comprise glycerine and propylene glycol, and wherein the ratio of the weight percent glycerine content to the weight percent propylene glycol content of the nicotine formulation is greater than or equal to about 1 .5.

[0043] In an example, the formulation may comprise: one or more aerosol formers; and one or more polymers selected from the group consisting of: polyvinyl acetate, polyvinyl alcohol, polyethylene glycol, polyglycolic acid, polylactic acid, polydioxanone, polycaprolactone, polyethylene, polypropylene glycol and starch; wherein the formulation has a melting point of between 100 degrees Celsius and 300 degrees Celsius.

[0044] In an example, the formulation may comprise: one or more aerosol formers; one or more metal salts; and one or more polymeric thickening agents, wherein the formulation has a polymeric thickening agent content of greater than or equal to about 0.5 percent by weight, wherein the one or more metal salts include one or more metal stearates.

[0045] The aerosol-generating device and / or the aerosol-generating system may be a portable device and / or system. It may be battery powered. Particularly, the aerosol-generating device and / or the aerosol-generating system may be pocket-size, hand-held, suitable for one-hand useand / or may weigh less than 300 grams, preferably less than 200 grams. It may be shaped and / or sized to fit snugly into a user’s hand. It may be carried in jacket and / or trouser pockets. Particularly, the aerosol-generating device and / or the aerosol-generating system may be configured to provide aerosol for human inhalation and / or human consumption, particularly inhalation and / or consumption through the mouth.

[0046] During operation of the aerosol-generating system, the dielectric heater may heat the formulation in the first segment such that a dynamic viscosity of the formulation entering the second segment is in a range of 45 to 1 mPa / s (centipoise cP), preferably 30 to 2 mPa / s, and more specifically 15 to 4 mPa / s.

[0047] According to a fourth aspect, there may be provided a method for aerosol-generation, comprising: preheating a formulation comprising one or more of liquids, semi-liquids, and solids by dipole rotation to decrease viscosity of the formulation, and aerosolizing and / or vaporizing the preheated formulation.The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0048] Example Ex1 . A heater module for an aerosol-generating device comprising:

[0049] a liquid channel comprising a first segment and a second segment, wherein the second segment is arranged downstream from the first segment,

[0050] a dielectric heater arranged at the first segment, wherein the dielectric heater is configured to dielectrically heat a formulation when received in the first segment by dipole rotation,

[0051] an atomizer arranged at the second segment and configured to aerosolize and / or vaporize the formulation after entering the second segment.

[0052] Example Ex2. The heater module according to the preceding example, wherein, during operation, the dielectric heater heats the formulation in the first segment such that a dynamic viscosity of the formulation entering the second segment is lowered to be in a range of 45 to 1 mPa / s (centipoise cP), preferably 30 to 2 mPa / s (centipoise), and more specifically 15 to 4 mPa / s (centipoise).

[0053] Example Ex3. The heater module according to example Ex1 or example Ex2, wherein the dielectric heater at the first segment comprises at least two electrodes configured to heat the formulation by an alternating electric field formed by the at least two electrodes in the first segment.

[0054] Example Ex3.1. The heater module according to the preceding example, wherein the dielectric heater comprises an oscillation circuit, wherein the oscillation circuit comprises a switching unit with a feedback loop connected between the input and the output of the switching unit, wherein the feedback loop comprises one or more inductors and a load capacitor formed by the at least two electrodes.Example Ex4. The heater module according to any one of the preceding examples, wherein the at least two electrodes comprise one or more pairs of electrodes arranged, for example but not limited to in parallel, along a longitudinal direction of the first segment.

[0055] Example Ex4.1. The heater module according to the preceding example, wherein the one or more pairs of electrodes are arranged to form a cylindrical, oval, or other tubular arrangement, for example to form a flow path inside or outside of the tubular arrangement, or to form a flow path between the individual electrodes.

[0056] Example Ex4.2. The heater module according to example Ex4 or example Ex4.1 , wherein the at least two electrodes may comprise one or more pairs of electrodes arranged, for example but not limited to in parallel, preferably as parallel strips, bars, or pins, along a longitudinal direction of the first segment.

[0057] Example Ex4.3. The heater module according to example Ex4 or example E4.1, wherein the at least two electrodes are plate shaped.

[0058] Example Ex5. The heater module according to any one of the preceding examples, wherein the first segment comprises two channels that are separated from each other, each channel having a respective dielectric heater configured to heat the formulation independently, and wherein the second segment is arranged between the two channels.

[0059] Example Ex6. The heater module according to any one of the preceding examples, wherein the first segment defines or comprises a sleeve portion extending in a longitudinal direction, and the second segment is at least partially formed within the sleeve portion, preferably in a concentric configuration relative to the sleeve portion.

[0060] Example Ex6.1. The heater module according to the preceding example, wherein the second segment is contiguous to the first segment.

[0061] Example Ex6.2. The heater module according to example Ex6 or example Ex6.1 , wherein one or more of the first segment and the second segment have a tubular form, such as a cylindrical or oval form.

[0062] Example Ex6.3. The heater module according to any one of examples Ex6 to Ex6.2, wherein a smallest diameter of the second segment is smaller than a smallest diameter of the first segment.

[0063] Example Ex7. The heater module according to any one of the preceding examples, wherein the atomizer includes a vaporizer configured to heat the formulation to vaporize the formulation.

[0064] Example Ex8. The heater module according to any one of the preceding examples, wherein the vaporizer includes at least one of a resistive heater, an infrared heater, or an inductive heater.Example Ex9. The heater module according to any one of examples Ex1 to Ex8, wherein the vaporizer includes a dielectric heater configured to dielectrically heat the formulation in the second segment by dipole rotation.

[0065] Example Ex10. The heater module according to the preceding example, wherein the dielectric heater at the second segment comprises at least two electrodes configured to heat the formulation by an alternating electric field formed by an alternating voltage applied to the at least two electrodes in the second segment.

[0066] Example Ex10.1. The heater module according to the preceding example, wherein the at least two electrodes at the first segment and the at least two electrodes at the second segment are electrically insulated from each other.

[0067] Example Ex11 . The heater module according to the preceding example, wherein the at least two electrodes at the first segment and the at least two electrodes at the second segment are mechanically and electrically connected, to form a single capacitor.

[0068] Example Ex12. The heater module according to any one of examples Ex10 to Ex11 , wherein the at least two electrodes at the first segment define a first electrode arrangement, and the at least two electrodes at the second segment define a second electrode arrangement that differs from the first electrode arrangement, preferably by one or more of: a shape and a distance between the respective two electrodes of the first and second segments.

[0069] Example Ex13. The heater module according to any one of the preceding examples, wherein the atomizer comprises a mechanical atomizer configured to convert the formulation into droplets.

[0070] Example Ex13.1. The heater module according to the preceding example, wherein the mechanical atomizer comprises a mesh or membrane with a plurality of apertures, and a vibrator, such as a piezoelectric element, configured to vibrate the mesh or the membrane.

[0071] Example Ex13.2. The heater module according to example Ex13 or example Ex13.1 , wherein the first channel forms a canister for storing a liquid formulation, the canister is fluidly connected to a spraying nozzle, wherein the liquid formulation in the interior of the canister is dielectrically heated up by the dielectric heater before being atomized by the spraying nozzle.

[0072] Example Ex14. The heater module according to any one of the preceding examples, comprising a liquid transfer element at least partially arranged in the second segment, wherein the liquid transfer element comprises a capillary flow structure to guide movement of the formulation from the first segment to the second segment.

[0073] Example Ex14.1. The heater module according to the preceding example, wherein the liquid transfer element comprises a porous structure or microchannels adapted for capillary transport of the formulation.

[0074] Example Ex14.2. The heater module according to example Ex14 or example Ex14.1 , wherein the liquid transfer element extends into a part of the first segment.Example Ex14.3. The heater module according to example Ex14 or example Ex14.1 , wherein the liquid transfer element is not arranged in the first segment.

[0075] Example Ex15. The heater module according to any one of the preceding examples, comprising a temperature sensor configured to measure a temperature of the formulation at the first segment and / or at the second segment, and

[0076] a controller connected to the dielectric heater and the temperature sensor,

[0077] wherein the controller is configured to calculate a value for the viscosity based on the measured temperature and to control the dielectric heater based on the calculated viscosity to achieve a pre-defined dynamic viscosity of the formulation in the second segment.

[0078] Example Ex15.1. The heater module according to the preceding example, wherein the pre-defined dynamic viscosity is in a range of 30 to 1 mPa / s (centipoise), preferably 20 to 2 mPa / s (centipoise), and more specifically 10 to 4 mPa / s (centipoise).

[0079] Example Ex15.2. The heater module according to example Ex15 or example Ex15.1 , wherein the temperature sensor is a thermocouple.

[0080] Example Ex15.3. The heater module according to any one of examples Ex15 to Ex15.2, wherein the controller configured to operate the dielectric heater and the atomizer at the same time, to heat and aerosolize the formulation simultaneously.

[0081] Example Ex15.4. The heater module according to any one of examples Ex15 to Ex15.3, wherein the controller is configured to operate the dielectric heater before the atomizer and / or alternately, to heat the formation at a first time instance and aerosolize the formulation at a second time instance after the first time instance.

[0082] Example Ex16. An aerosol-generating device comprising

[0083] a battery and

[0084] a heater module according to any one of the preceding examples connected to the battery for powering the heater module, in particular the dielectric heater and / or the atomizer thereof.

[0085] Example Ex17. An aerosol-generating system comprising

[0086] a cartridge holding a formulation, and

[0087] an aerosol-generating device according to any one of the preceding examples configured to aerosolize the formulation.

[0088] Example Ex17.1 . The aerosol-generating system according to the preceding example, wherein the formulation comprises one or more of liquids, semi-liquids, and solids.

[0089] Example Ex17.2. The aerosol-generating system according to example Ex17 or example Ex17.1 , wherein the formulation comprises polypropylene glycol (PPG), vegetable glycerol (VG), Terpenes, Triacetin, PDO (1 ,3-Propanediol), MCT Oil (Medium-Chain Triglycerides) or a combination thereof.

[0090] Example Ex18. A method for aerosol-generation, preferably performed by any one of the heater module according to any one of examples Ex1 to Ex15.4, the aerosol-generatingdevice according to example Ex16 or by the aerosol-generating system according to any one of examples E17 to E17.2, comprising:

[0091] Preheating a formulation comprising one or more of liquids, semi-liquids, and solids by dipole rotation to decrease viscosity of the formulation, and

[0092] Aerosolizing and / or vaporizing the preheated formulation.

[0093] As used herein, the term “formulation” may relate to an aerosol-generating formulation. The aerosol-generating formulation may have a liquid, semi-liquid, and / or solid form at room temperature (20°C) and is capable of becoming liquid and / or less viscous when heated, for example through melting. The formulation may comprise aerosol formers, for example, polypropylene glycol (PPG), glycerol such as vegetable glycerol (VG), or other known aerosol formers.

[0094] As used herein, the term “aerosol” may relate to a suspension of particulates including fine liquid droplets in a gas, typically air.

[0095] As used herein, the term “vapor” may relate to a gaseous phase of a formulation that has transitioned from a liquid or solid state due to heating. Vapor may exist independently as a gas. The gas may condense into fine liquid droplets when mixed with cooler air, thereby forming aerosol.

[0096] The term "liquid channel" may relate to a pathway designed for the transfer of liquid and semi-liquid formulations capable of being vaporized, and ultimately aerosolized, or aerosolized by mechanical means. The liquid channel may be designed to optimize flow dynamics and reduce the risk of blockages, with flow caused by mechanisms such as capillary action, gravity, pumps, vacuum suction, or peristaltic motion. In some embodiments, the first segment of the liquid channel may serve as or is part of a reservoir designed to store the formulation. The reservoir may take the form of a cartridge that stores the formulation that may be removably attached to (e.g., inserted in) and detached from the heater module or aerosol-generating device. The dielectric heater for preheating the formulation may be attached to any of the cartridge and / or the device. In other embodiments, the first segment, or at least a part thereof, defines a compartment for accommodating the solid formulation or a substrate capable of becoming liquid when heated. An opening may be formed in the heater module or device to receive the (solid) formulation or at least a part thereof.

[0097] As used herein, the term “aerosol-generating device” may relate to an electronic cigarette for heating an e-liquid, such as tobacco-flavored e-liquids, or a nebulizer or similar medical product configured to generate aerosol by atomizing a liquid, semi-liquid or even solid formulation, such as a medicated liquid solution, through mechanical, specifically ultrasonic, or jet-based means. The generated aerosol may facilitate inhalation therapy by delivering active pharmaceutical ingredients (APIs) directly to the respiratory system of a user. The aerosolgenerating device may be a handheld device with a battery and a heater module connected tothe battery for powering the heater module, in particular the dielectric heater and / or the atomizer thereof. The aerosol-generating device may comprise a formulation storage cavity for receiving a formulation or a replaceable cartridge storing the formulation.

[0098] As used herein, the term “aerosol-generating system” may relate to a combination of an aerosol-generating device and an aerosol-generating formulation.

[0099] As used herein, the term “puff” may mean the action of a user drawing an aerosol into their body through their mouth or nose.

[0100] The invention will be further described, by way of example only, with reference to accompanying drawings in which:

[0101] Figure 1A is a schematic block diagram of a heater module according to embodiments of the disclosure;

[0102] Figure 1 B is a schematic illustration of an aerosol-generating device with a heater module according to an embodiment of the disclosure, where a dielectric heater for preheating in form of a load capacitor with a pair of electrodes is used;

[0103] Figure 2 is a diagram illustrating the temperature-dependent viscosity of an aerosol former added in an aerosol-generating formulation;

[0104] Figures 3-5 are schematic illustrations of heater modules according to embodiments of the disclosure, in which a thermal atomizer (vaporizer) is used to generate vapor; and

[0105] Figures 6A and 6B are schematic illustrations of heater modules according to embodiments of the disclosure, in which a non-thermal atomizer (mechanical atomizer, for example vibrator) is used to generate aerosol.

[0106] In the drawings presented herein, the formulation is depicted using the symbol “+” when in a liquid, semi-liquid, or solid state, while arrows indicate its vaporized and / or aerosolized state, pointing in the direction of the flow of aerosol and / or vapor.

[0107] Figure 1A is a schematic block diagram of a heater module 1 for an aerosol-generating device 100 implementing a two-stage process for generating inhalable aerosol, using a dielectric heater 2 for preheating a liquid or liquefiable aerosol-generating formulation (not shown) to make the formulation liquid or less viscous, and an atomizer 3 to aerosolize and / or vaporize the preheated formulation, either by thermal means as described with respect to Figure 3 to Figure 5 or non-thermal means as shown in Figure 6A and Figure 6B.

[0108] Figure 1 B is a schematic circuit diagram of the aerosol-generating device 100 having a battery 4 and the heater module 1 according to Figure 1 A operatively connected to each other via a controller 5, for example but not limited to a microcontroller. The heater module 1 comprises a liquid channel 6 besides the dielectric heater 2 and the atomizer 3. The liquid channel 6 comprises a first segment 61 and a second segment 62 arranged downstream from the first segment 61 . The dielectric heater 2 comprises a load capacitor based dielectric heater having a pair of electrodes 21 arranged at the first segment 61. In the shown non-limiting example, the electrodes21 are in form of two parallel arranged electrode plates with the first segment 61 of liquid channel 6 arranged therebetween. The electrodes 21 are connected to an oscillation circuit 22 configured to provide electrodes 21 with an alternating radio frequency (RF) voltage to dielectrically heat the formulation 7 by an alternating radio frequency (RF) electric field formed by the at least two electrodes 21 in the first segment 61. The atomizer 3 is arranged at the second segment 62 and is configured to vaporize or aerosolize the formulation after entering the second segment 62. Notably, while the dielectric heater 2 is shown to include the two electrodes 21 of the load capacitor connected to the oscillation circuit 22 herein, it is also possible that other types of dielectric heaters are used, for example resonant cavities fed with a microwave, loop gap resonators, transmission lines fed by a microwave, and combinations thereof. For example, the resonant cavity can have two openings as inlet and outlet for the first segment 61.

[0109] The aerosol-generating device 100 further comprises a temperature sensor 80, for example but not limited to a thermocouple or PTC / NTC temperature sensor, operatively connected to the controller 5 for example in a feedback loop configuration and is configured to measure a temperature of the formulation 7, for example but not limited to at the second segment 62. The controller 5 is configured to calculate a value for the viscosity of the formulation 7 based on the measured temperature and can control the heating power that is delivered by the oscillation circuit 22 of the dielectric heater 2 based on the calculated viscosity to achieve a pre-defined dynamic viscosity. For example, the heating power of the dielectric heater 2 can be controlled in various ways, for example by increasing or decreasing the voltage supplied to the oscillation circuit 22, power supply control to the oscillation circuit 22 by PWM or on-off control via a switch, frequency control, etc. In some examples, the controller 5 forms part of the heater module 2. In the present non-limiting example, the controller 5 is the main controller responsible for operating the entire aerosol-generating device 100.

[0110] Figure 2 is a diagram illustrating the temperature-dependent dynamic viscosity in centipoise ([cP] = 1 mPa / sec) of polypropylene glycol (PPG), a common aerosol-forming agent found in formulations 7 over temperature in °C. PPG is significantly more viscous than water but decreases exponentially with temperature. At 20°C, water has a viscosity of 1 cP, while PPG is about 90 cP. At 80°C, the viscosity of water drops to 0.35 cP, whereas the viscosity of PPG remains around 4 cP, hence still over 10 times higher. The controller 5 as illustrated in Figure 1B may regulate the dielectric heater 2 to maintain a viscosity of the formulation 7 between 1 to 45 cP, preferably 2 to 30 cP, and ideally 4 to 15 cP. PPG as an aerosol-forming agent or carrier substrate for the liquid formulation is exemplary only, and is herewith used to visualize the effects of the viscosity change that can be caused by dielectric heating. Other liquids or semi-liquids can be used, for example ones that are highly viscous at room temperature, e.g. preferably more than 1000 cP at room temperature of 20°C, more preferably more than 10000 cP at room temperature, but highlyviscous at an elevated temperature, e.g. less than 100 cP at 100°C, more preferably less than 50 cP at 100°C.

[0111] Figure 3 to Figure 5 show different variants of the heater module 1 from Figure 1A in schematic illustrations, in which the atomizer 3 includes a vaporizer 31 to heat and thus generate vapor at the second segment 62. In these variants, the heater module 3 comprises a liquid transfer element 8, for example embodied as a wicking element, arranged at the second segment 62 with a capillary flow structure and / or gravity-based flow to guide movement of the formulation 7 from the first segment 61 to the second segment 62. The liquid transfer element 8 can have a porous structure or microchannels adapted for capillary transport of the formulation 7. Other ways of feeding or transporting the liquid formulation is also possible, for example by an active means, such as pumps, injectors, valves, etc.

[0112] Figure 3A and Figure 3B show two different variants of the heater module 1 , in which the vaporizer 31 includes a load capacitor as dielectric heater 2. The load capacitor has two electrodes 21 in form of two parallel arranged electrode plates with the second segment 62 arranged therebetween. In these variants, the space spanned between the electrode plates at the second segment 62 is filled with the liquid transfer element 8. Before preheating, the formulation 7 received in the first segment 61 and / or in a formulation storage reservoir 9 (also called oil storage cavity, volume or canister) fixed or removably connected to the first segment 61 of the heater module 1 can be in a state where the capillary flow into the liquid transfer element 8 is not possible or strongly impeded due to the high viscosity of the formulation 7, whilst upon performing preheating operation, the formulation 7 is fluidized and allows to wet, soak, or otherwise ingress into the liquid transfer element 8. Once the liquid transfer element 8 is at least partially soaked, the vaporizing heating at the second segment 62 is performed.

[0113] In the shown variants, both the preheating and the vaporizing heating can be formed by the same dielectric heater fed by a single oscillation circuit 22. The electrodes 21 of the load capacitor contiguously extend over the first segment 61 and the second segment 62. Preheating of formulation 7 at the first segment 61 and the vaporizing heating of the formulation 7 at the second segment 72 can thus happen simultaneously. With the single heater set-up, the heating power of the dielectric heater in a respective segment can be adjusted by having different distances d1 and d2 between the two electrodes 21 at the first segment 61 and the second segment 62, respectively, or different electrode arrangements.

[0114] In the variant shown in Figure 3A, a first portion of the electrodes 21 at the first segment 61 has a larger distance d1 compared to a distance d2 between a second portion of the electrodes 21 at the second segment 62. This design results in lower heating energy per volume in the first segment 61 , as vaporization is not intended in that area.

[0115] In the variant shown in Figure 3B, the distances between the electrodes 21 are same (d1=d2).While the above variations depict a single dielectric heater, other variants may incorporate two mechanically separated and / or electrically insulated dielectric heaters, for example each one having a separate oscillator, one for preheating and the other for vaporization heating. The two dielectric heaters may be used to measure presence / absence or even fill level of the formulation 7 between the respective electrodes due to the change of dielectric response.

[0116] Figure 4A and Figure 4B illustrate variants where two different heater types are used for vaporization and preheating, showing a partial view of an e-liquid capsule or cartridge that can be removably or fixedly connected with a cartridge holder of the heater module 1 or aerosolgenerating device 100. That is, in contrast to the variants in Figures 3A and 3B, the vaporizer 31 is not implemented as dielectric heater but relies on another heating principle. Thereby, at a first time instant, the dielectric heater 2 is powered for liquefying the formulation 7 and thereafter, at a second time instant, the vaporizer 31 is powered. In the time between, the liquid transfer element 8 can become fully or partially soaked, preferably soaked to a high soak percentage. Accordingly, the dielectric heater 2 together with the formulation 7 can act like a valve element or device for controlling a flow rate of the formulation 7. During vaporizing heating, the valve can be considered open and the formulation 7 is liquefied for flow towards the second segment 62. When no heating is performed, the first segment 61 acts like a closed valve or a flow restrictor, due to the increased viscosity at lower temperatures. In other words, the dielectric heater 2 with the formulation 7 can act as a dose control valve, to allow a certain volume of liquid to pass to the vaporizer 31.

[0117] In the variant of the heater module 1 shown in Figure 4A, the vaporizer 31 includes a resistive or Joule-type heater 32, in particular, a mesh or wire plate-type heater bonded to a lower surface of the liquid transfer element 8 opposite to a liquid ingress surface 81 of the liquid transfer element 8 where the preheated formulation 7 is received. The resistive heater 32 has two electric contacts 33 to receive electrical power.

[0118] In the present variant, the first segment 61 of the liquid channel 6 may comprise two channels 611, 612 that may or may not be fluidically separated from each other. Each channel may have a respective dielectric heater configured to heat the formulation 7 received in the respective channel independently. In particular, the dielectric heater 2 of Figure 1 A includes a first dielectric heater with a first pair of electrodes 211 and a second dielectric heater with a second pair of electrodes 212, either both connected to the same oscillator or each pair with a separate oscillator. Each dielectric heater covers at least a respective liquid ingress surface 81 of the liquid transfer element 8, with an aerosol channel 10 (also referred to as an air tube) positioned between them. The aerosol channel 10 extends to a vapor egress surface 82 of the liquid transfer element 8, which is located on the same side as the liquid ingress surfaces 81 and opposite to the surface where the resistive heater 32 is positioned.

[0119] Air inlets 11 are arranged upstream to the liquid transfer element 8, for example in a bottom wall of the cartridge or capsule, and the aerosol channel with respect to the air flow path of theheater module 1 to pull external air, which in operation, is subsequently mixed with the vapor at the vapor egress surface 82. This process leads to condensation into tiny liquid droplets, forming an inhalable mist commonly known as aerosol in the aerosol channel 10.

[0120] Although the two pairs of electrodes 211, 212 are shown to be arranged to cover the volume in the formulation storage reservoir 9 to subject this area and the liquid ingress surface 81 with an alternating electric field, the variant is not limited thereto. For example, the two pairs of electrodes 211 , 212 may be arranged between the formulation storage reservoir 9 and the liquid ingress surface 81.

[0121] Contrary to the variant shown in Figure 4A, in the variant shown in Figure 4B, the capsule or cartridge includes a vaporizer 31 that includes a resistive heating coil in a classis wick-and-coil configuration wound around the liquid transfer element 8. In a variant, heating coil could be an inductive heating element where, the liquid transfer element 8 holds or has one or more susceptors embedded therein that heats up upon electromagnetic interaction with the heating coil. The two pairs of electrodes 211, 212 have electrical contacts 23 to connect them to the battery 4 via the oscillation circuit 22 or another driver circuit. Liquid formulation 7 can be fed to both ends of the liquid transfer element 8 for liquid feeding. As shown in Figure 4B, two terminals pairs, electrical contacts 23, 33, are arranged at the bottom floor of cartridge, to removably interconnect with the power signals for each heater.

[0122] Figure 5 shows another variant of the heater module 1 of Figure 1A, where in contrast to the variant shown in Figure 4A, multiple pairs of electrodes 213 extending in parallel to a rotational axis, for example but not limited to a rotational axis extending along a longitudinal direction of the first segment 61, heater module 1 and / or aerosol-generating device 100, and arranged to form an annular arrangement, preferably tubular arrangement, are shown, for example interdigitated electrodes 213 arranged as parallel electrode strips. The multiple pairs of electrodes 213 can have a flat or, as shown, slightly curved shape. In this variant, the multiple pairs of electrodes 213, the first segment 61, the resistive heater 32, for example but not limited to a mesh-type heater layer positioned on the outer surface of the liquid transfer element 8, and the aerosol channel 10 are arranged concentrically in the specified order from the outside to the inside. The first segment 61 includes an annular space for receiving the formulation 7. The multiple pairs of electrodes 213, for example being part of a pod or cartridge holder, heat the formulation 7 such that the pre-heated formulation can be soaked into the liquid transfer element 8 by passing through apertures between the elements of the resistive heater 32.

[0123] Figure 6A and Figure 6B illustrate different variations of the heater module 1 from Figure 1A, where non-thermal aerosolization is achieved through the use of a mechanical atomizer 35. The mechanical atomizer 35 comprises a vibrating mesh or membrane 351 with a plurality of apertures 352. The membrane 351 is vibrated by a vibrator 353, for example a piezo-actuator.In the present variant, the formulation 7 is fed via both a capillary channel and non-capillary channel, in particular by gravity-driven flow, through the first segment 61 to the second segment 62 while being preheated by the dielectric heater 2 with an alternating electric field created by the electrodes 21 and the oscillation circuit 22. The second segment 62 forms a liquid chamber for storing and supplying the preheated formulation 7 to the mechanical atomizer 35, which may be arranged to cover an upper opening of the chamber.

[0124] In another non-shown variant, the dielectric heater 2 can preheat the formulation 7 closer to or in contact with the vibrating mesh 351 , such that preheating is formed just below the lower surface of the vibrating mesh 351. Also, other types of mechanical atomizers can be used, such as ultrasonic atomizers, or spray-type atomizers, like jet nebulizers. For example, at least a portion of a liquid reservoir of a spray-type atomizer can be heated by a first segment 61 , before the dielectrically heated and thereby liquified formulation reaches the spray nozzle mechanism for atomization.

[0125] A temperature sensor 80 is arranged to measure the temperature of the preheated formulation 7, in the variant shown arranged upstream before the mechanical atomizer 35. It may be thus possible to first preheat the formulation 7 until a desired temperature for the formulation 7 is reached and thereafter power the mechanical atomizer 35 for atomizing the formulation 7.

[0126] Unlike the variant shown in Figure 6A, Figure 6B presents a variant where the flow path from the formulation storage reservoir 9 to an aerosol chamber 12 is arranged from top to bottom, to take advantage of the gravity-type feeding of the formulation 7. The space between electrodes 21 can be equipped with or without a liquid transfer element 8. Also, electrodes 21 are shown to have a flanged portion with an increased distance downstream to apply for a heating power gradient to liquid formulation. In this configuration, the aerosol generated by the mechanical atomizer 35 mixes with external air drawn in through the air inlets 11 when the user takes a puff. Additionally, the temperature sensor 80 is positioned on the vibrating mesh 351 or the substrate that forms the vibrating mesh 351 to directly measure the temperature of the formulation 7 at the mesh, ensuring precise temperature control.

Claims

Claims1. A heater module for an aerosol-generating device comprising:a liquid channel comprising a first segment and a second segment, wherein the second segment is arranged downstream from the first segment,a dielectric heater arranged at the first segment, wherein the dielectric heater is configured to dielectrically heat a formulation when received in the first segment by dipole rotation,an atomizer arranged at the second segment and configured to aerosolize and / or vaporize the formulation after entering the second segment.

2. The heater module according to the preceding claim, wherein the dielectric heater at the first segment comprises at least two electrodes configured to heat the formulation by an alternating electric field formed by the at least two electrodes in the first segment.

3. The heater module according to any one of the preceding claims, wherein the at least two electrodes comprise one or more pairs of electrodes arranged along a longitudinal direction of the first segment.

4. The heater module according to any one of the preceding claims, wherein the first segment comprises two channels that are separated from each other, each channel having a respective dielectric heater configured to heat the formulation independently, and wherein the second segment is arranged between the two channels.

5. The heater module according to any one of the preceding claims, wherein the first segment defines or comprises a sleeve portion extending in a longitudinal direction, and the second segment is at least partially formed within the sleeve portion, preferably in a concentric configuration relative to the sleeve portion.

6. The heater module according to any one of the preceding claims, wherein the atomizer includes a vaporizer configured to heat the formulation to vaporize the formulation.

7. The heater module according to any one of the preceding claims, wherein the vaporizer includes at least one of a resistive heater, an infrared heater, or an inductive heater.

8. The heater module according to claim 6 or 7, wherein the vaporizer includes a dielectric heater configured to dielectrically heat the formulation in the second segment by dipole rotation.

9. The heater module according to the preceding claim, wherein the dielectric heater at the second segment comprises at least two electrodes configured to heat the formulation by an alternating electric field formed by an alternating voltage applied to the at least two electrodes in the second segment.

10. The heater module according to the preceding claim, wherein the at least two electrodes at the first segment and the at least two electrodes at the second segment are mechanically and electrically connected, to form a single capacitor.11 . The heater module according to any one of claims 9 to 10, wherein the at least two electrodes at the first segment define a first electrode arrangement, and the at least two electrodes at the second segment define a second electrode arrangement that differs from the first electrode arrangement, preferably by one or more of: a shape and a distance between the respective two electrodes of the first and second segments.

12. The heater module according to any one of the preceding claims, wherein the atomizer comprises a mechanical atomizer configured to convert the formulation into droplets.

13. The heater module according to any one of the preceding claims, comprising a liquid transfer element at least partially arranged in the second segment, wherein the liquid transfer element comprises a capillary flow structure to guide movement of the formulation from the first segment to the second segment.

14. The heater module according to any one of the preceding claims, comprising a temperature sensor configured to measure a temperature of the formulation at the first segment and / or at the second segment, anda controller connected to the dielectric heater and the temperature sensor,wherein the controller is configured to calculate a value for the viscosity based on the measured temperature and to control the dielectric heater based on the calculated viscosity to achieve a pre-defined dynamic viscosity of the formulation in the second segment.

15. An aerosol-generating system comprisinga cartridge holding a formulation, andan aerosol-generating device comprising a battery and a heater module according to any one of the preceding claims connected to the battery for powering the heater module,wherein, during operation, the dielectric heater heats the formulation in the first segment such that a dynamic viscosity of the formulation entering the second segment is in a range of 45 to 1 mPa / s (centipoise cP), preferably 30 to 2 mPa / s, and more specifically 15 to 4 mPa / s.

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