Heater assembly

Abstract

A heater assembly (300) is provided for use in an aerosol generating system (100). The heater assembly (300) comprises a liquid aerosol-forming substrate including at least two compounds, a first compound having a first boiling point and a second compound having a second boiling point. The heater assembly (300) includes a retaining material (302) containing the aerosol-forming substrate. The heater assembly also includes a heating element (304) configured to heat the retaining material by passing an electric current along a length of the heating element, the heating element (304) being formed from a strip of material, the cross-sectional area of ​​which decreases progressively along the length of the strip of material to provide a temperature gradient along a surface of the retaining material (302).

Description

Technical Field

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[0003]

[0001] The present disclosure relates to a heater assembly. Specifically, the present disclosure relates to a heater assembly for use in an aerosol generation system. The present disclosure also relates to a cartridge comprising the heater assembly, an aerosol generation system comprising the heater assembly, and a method for heating a liquid aerosol forming substrate within the heater assembly.

Background Art

[0002] In many well-known aerosol generation systems, a liquid aerosol forming substrate is heated and vaporized to form a vapor. The vapor cools and condenses to form an aerosol. In some aerosol generation systems, such as electric heating smoking systems, this aerosol is then inhaled by a user.

[0003] Typically, a liquid aerosol forming substrate contains several compounds that vaporize when heated. These compounds may have different boiling points. For example, the liquid aerosol forming substrate may contain nicotine (which has a boiling point of approximately 247 degrees Celsius at atmospheric pressure) and glycerol (which has a boiling point of approximately 290 degrees Celsius at atmospheric pressure). [[ID=IS]]

[0004] When a liquid aerosol forming substrate containing compounds with different boiling points is being heated, the compounds with lower boiling points may vaporize before the compounds with higher boiling points. Alternatively or additionally, the compounds with lower boiling points may vaporize at a higher rate than the compounds with higher boiling points.

[0005] This may be undesirable because it may limit the interactions and combinations between different compounds. For example, a liquid aerosol-forming substrate may contain nicotine compounds and organic acid compounds, and these compounds have different boiling points. Both of these compounds may vaporize. Nicotine in a liquid aerosol-forming substrate may form free base nicotine when vaporized. However, it may be desirable to generate an aerosol containing a nicotine salt rather than free base nicotine. To form this nicotine salt, the free base nicotine may be protonated by the vaporized organic acid. However, this protonation may be limited if the organic acid does not vaporize until after the nicotine has vaporized, or if the organic acid vaporizes more slowly than necessary to protonate a suitable ratio of free base nicotine.

[0006] Furthermore, the vaporization of some compounds in the aerosol-forming substrate at a higher rate than others can unnecessarily alter the properties of the generated aerosol over time (for example, during fume extraction in an aerosol-generating system). This is because, as the heating element is activated and its temperature rises towards the start of fume extraction, the liquid aerosol-forming substrate near the heating element may reach a first temperature, at which point the first compound with a lower boiling point vaporizes, while the second compound with a higher boiling point does not. Subsequently, later in the fume extraction, the liquid aerosol-forming substrate near the heating element may reach a second temperature, at which point the second compound with a higher boiling point vaporizes. However, by this point, most of the first compound in the liquid aerosol-forming substrate near the heating element may have already vaporized. Therefore, towards the start of fume extraction, the generated aerosol may contain a larger proportion of the first compound, and later in the fume extraction, the generated aerosol may contain a larger proportion of the second compound.

[0007] Alternatively, or additionally, the properties of the generated aerosol may change over several vapor extractions. This may occur if the compounds of the liquid aerosol-forming substrate do not vaporize at an appropriate rate. For example, the liquid aerosol-forming substrate may contain X mass percent of a first compound and Y mass percent of a second compound. If the liquid aerosol-forming substrate does not vaporize to produce a vapor containing the first compound to the second compound in a mass ratio of X to Y, the composition of the liquid aerosol-forming substrate may change as the vapor is generated. This, in turn, may lead to a change in the properties of the aerosol generated by the liquid aerosol-forming substrate. [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to control the vaporization of various compounds of a liquid aerosol-forming substrate, which have different boiling points. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, a heater assembly for use in an aerosol generating system is provided, the heater assembly may comprise a liquid aerosol-forming substrate. The liquid aerosol-forming substrate may comprise at least two compounds, the first having a first boiling point and the second having a second boiling point. The heater assembly may comprise a holding material containing the liquid aerosol-forming substrate. The heater assembly may comprise a heating element configured to heat the holding material by passing an electric current along the length of the heating element. The heating element may be formed from a strip of material, the cross-sectional area of ​​the strip of material progressively decreasing along the length of the strip of material, and providing a temperature gradient along the surface of the holding material.

[0010] The cross-sectional area of ​​the material strip may gradually decrease along the length of the material strip, from the maximum cross-sectional area of ​​the material strip at the first end of the material strip to the minimum cross-sectional area of ​​the material strip at the second end of the material strip.

[0011] The heater assembly may provide an area along the surface of the retaining material where the temperature rises at a faster rate, and an area where the temperature rises at a slower rate.

[0012] Advantageously, heater assemblies may improve control over the vaporization of different compounds of the liquid aerosol-forming substrate. Heater assemblies may result in the simultaneous vaporization of liquid aerosol-forming substrate compounds with higher and lower boiling points at a desired rate. Heater assemblies may result in the vaporization of liquid aerosol-forming substrate compounds with higher and lower boiling points in a more favorable ratio. Heater assemblies may provide the generation of aerosols with a more desirable composition. Heater assemblies may provide more consistent generation of aerosols with desirable properties.

[0013] The material strip may have a cross-sectional area that gradually decreases along the length of the material strip. The width of the material strip may gradually decrease along the length of the material strip. Alternatively, or additionally, the thickness of the material strip may gradually decrease along the length of the material strip.

[0014] The strip of material may be folded itself to provide at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of material.

[0015] At least one overlapping portion may provide a portion of the heating element at a lower temperature than adjacent non-overlapping portions of the material strip. The material strip itself may be folded any number of times along the length of the material strip. For example, the material strip itself may be folded along the length of the material strip to provide one, two, three, four, five, six, seven, eight, nine, or ten overlapping portions.

[0016] Advantageously, the folding of the material strip itself and the resulting overlap of at least one portion may create a larger area of ​​higher temperature and a larger area of ​​lower temperature along the surface of the retaining material. Alternatively, or additionally, this may provide a larger area of ​​faster temperature rise and a larger area of ​​slower temperature rise along the surface of the retaining material. This may lead to the simultaneous vaporization at a favorable rate of liquid aerosol-forming substrate compounds having higher and lower boiling points. Advantageously, the manufacture of a heating element formed from a folded material strip may require only a simple manufacturing process.

[0017] The heating element may contain two or more materials. The heating element may contain a first heating element material and a second heating element material. The second heating element material may be different from the first heating element material. The first heating element material may be located at a first position along the length of the material strip. The second heating element material may be located at a second position along the length of the material strip. The first heating element material may have a first electrical resistivity, and the second heating element material may have a second electrical resistivity different from the first electrical resistivity.

[0018] Advantageously, a heating element comprising two or more materials may provide an increased temperature gradient along the surface of the retaining material. This increased temperature gradient may provide a larger area along the surface of the retaining material where the temperature rises more rapidly, and a larger area where the temperature rises more slowly. The increased temperature gradient may further influence the vaporization rate of different compounds within the liquid aerosol-forming substrate. As described above, this may lead to the generation of aerosols with a more desirable composition. Alternatively, or additionally, a heating element comprising two or more materials provides more consistent generation of aerosols with desirable properties.

[0019] The heating element, or a portion thereof, may include or be formed from any material having suitable electrical and mechanical properties, such as a suitable electrical-resistant material. Suitable materials include, but are not limited to, semiconductors such as doped ceramics, conductive ceramics (e.g., molybdenum disilide), carbon, graphite, metals, alloys, and composite materials made of ceramic and metallic materials. Such composite materials may include doped or undoped ceramics. An example of a suitable doped ceramic is doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Suitable alloys include stainless steel, constantan, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, iron-aluminum alloys, and iron-manganese-aluminum alloys. Timetal® is a registered trademark of Titanium Metals Corporation (1999 Broadway Suite 4300, Denver Colorado). In composite materials, the electrical resistive material may be embedded in, sealed in, or coated with an insulating material, depending on the required energy transfer dynamics and external physicochemical properties. The heating element, or portion thereof, may include etched metal foil insulated between two layers of inert material. In that case, the inert material may include Kapton®, full-layer polyimide, or mica foil. Kapton® is a registered trademark of EIdu Pont de Nemours and Company (1007 Market Street, Wilmington, Delaware 19898, United States of America).

[0020] The heater assembly may comprise multiple heating elements. Preferably, at least one heating element provides a temperature gradient along the surface of the retaining material. Preferably, a section of the retaining material is enclosed, or partially enclosed, within a volume defined between the two heating elements. The features described with respect to the first heating element may apply to any of the multiple heating elements.

[0021] A defined, enclosed, or partially enclosed volume between two heating elements may provide a temperature gradient along the surface of the retaining material.

[0022] The positioning of multiple heating elements may be used to increase the temperature gradient along the surface of the retaining material. Advantageously, the same material strip may be manufactured for various heater assemblies comprising multiple heating elements, and different temperatures or temperature gradients may be achieved by rearranging the heating elements. For example, a first heater assembly comprising two identical material strips may have a larger temperature gradient than a second heater assembly comprising two other identical material strips. The first heater assembly may have material strips positioned such that the portion of the material strip with substantially the smallest cross-sectional area is positioned closer together than the portion of the material strip with substantially the largest cross-sectional area. This may create a larger temperature gradient along the surface of the retaining material than in the second heater assembly, if the second heater assembly comprises identical material strips spaced at uniform distances. Thus, the first heater assembly may simultaneously vaporize liquid aerosol-forming substrate compounds with higher boiling points and liquid aerosol-forming substrate compounds with lower boiling points in different ratios.

[0023] The heating element may be in contact with the retaining material. The heating element may be on the surface of the retaining material. The heating element may be embedded within the retaining material, or partially embedded within it.

[0024] As described above, the positioning of a single heating element or a plurality of heating elements may be used to increase the temperature gradient along the surface of the holding material. This may lead to the simultaneous vaporization of liquid aerosol-forming matrix compounds having higher and lower boiling points at a desirable rate.

[0025] The heating element may be configured to be resistively heated. The strip of material may be perforated or may be a mesh.

[0026] Advantageously, a heating element comprising a mesh or a perforated strip of material may provide a large surface area. This large surface area may provide for efficient vaporization of the liquid aerosol-forming matrix.

[0027] The heater assembly may comprise a storage portion for storing the aerosol-forming matrix. The heater assembly may comprise a storage portion for the liquid aerosol-forming matrix. The term "storage portion" may be used to refer to a storage portion for storing the liquid aerosol-forming matrix or a storage portion for the liquid aerosol-forming matrix, unless otherwise explicitly stated. The storage portion may be configured to store or may store at least 0.2, 0.5, or 1 ml of the liquid aerosol-forming matrix. The storage portion may be configured to store or may store less than 2, 1.8, or 1.5 ml of the liquid aerosol-forming matrix.

[0028] The holding material may be a porous material. The holding material may be a ceramic material. The holding material is preferably a capillary holding material. The liquid aerosol-forming matrix storage component may store or may be configured to store the liquid aerosol-forming matrix.

[0029] The holding material may be in fluid communication with the reservoir. In this case, during use, the section of the heating element that is further away from the reservoir of the liquid aerosol-forming substrate, or the area within the holding material around these sections of the heating element, may reach a higher temperature than the section or area closer to the reservoir of the liquid aerosol-forming substrate. This is because, for the section of the heating element closer to the reservoir of the liquid aerosol-forming substrate, more heat may be transferred from the heating element to the reservoir of the liquid aerosol-forming substrate, or the heat may be transferred at a faster rate.

[0030] The holding material may include a material immersed in the liquid aerosol-forming substrate, or a material configured to be immersed in the liquid aerosol-forming substrate, or may be such a material. The holding material may have a fibrous or spongy structure. The holding material may include a capillary material. The holding material may comprise a bundle of capillaries. For example, the holding material may include one or more of fibers, threads, and microtubes.

[0031] The holding material may include a sponge-like or foam-like material. The structure of the holding material may form a plurality of small holes or tubes through which liquid can be moved by capillary action.

[0032] The holding material may include any suitable material or combination of materials. Suitable materials include sponge or foam materials, ceramic or graphite-based materials in the form of fibers or sintered powders, foamed metal materials or plastic materials, fibrous materials, such as fibrous materials made of spun fibers or extruded fibers (cellulose acetate, polyester, or combined polyolefins, polyethylene, terylene or polypropylene fibers, nylon fibers or ceramics, etc.), but are not limited thereto. The holding material may have any suitable capillary phenomenon and porosity for use with liquid aerosol-forming substrates having different physical properties.

[0033] It is preferable that the aerosol-forming substrate is absorbed into the holding material. The holding material may be configured to store, or may store, at least 0.02, 0.05, 0.1, 0.2, or 0.5 ml of liquid aerosol-forming substrate.

[0034] The heating element(s) may be configured to be heated, and may be heated to at least 50, 100, 150, 200, 250, 300, 350, or 400 degrees Celsius when in use. When in use, the fifth portion of the heating element may be heated to at least 50, 100, 150, 200, 250, 300, 350, or 400 degrees Celsius.

[0035] The minimum cross-sectional area of ​​the heating element along the length of the material strip may be at least 50 percent of the maximum cross-sectional area of ​​the heating element along the length of the material strip.

[0036] Advantageously, this can provide a predictable temperature difference along the length of the material strip. Therefore, it can provide a predictable temperature gradient along the surface of the retaining material.

[0037] The boiling point of the first compound may be 240°C to 250°C. The boiling point of the first compound may be 247°C. The boiling point of the second compound may be 285°C to 295°C. The boiling point of the second compound may be 290°C. The first compound may be nicotine, and the second compound may be glycerol. The temperature gradient along the surface of the holding material may be 247°C to 290°C. This may produce vaporized compounds of nicotine and glycerol in a preferred ratio.

[0038] According to another aspect of the present disclosure, a cartridge for use in an aerosol generating system is provided, which may comprise a heater assembly of the present disclosure.

[0039] The cartridge preferably includes an air intake and an air outlet, and the airflow path may be defined between the air intake and the air outlet. The heating element may be located downstream of the air intake. The heating element may be located upstream of the air outlet. The air drawn from the air intake to the air outlet may flow across, past, or through the heating element.

[0040] Advantageously, providing airflow across, past, or through a heater assembly or heating element may allow for the entrainment of steam formed by the heater assembly.

[0041] The air intake may be located closest to the portion of the heating element having substantially the lowest electrical resistance. The air outlet may be located closest to the portion of the heating element having substantially the highest electrical resistance.

[0042] During use, the air entering the air intake may be at ambient temperature. Advantageously, positioning the air intake closest to the portion of the heating element with substantially the lowest electrical resistance and the air outlet closest to the portion of the heating element with substantially the highest electrical resistance may increase the temperature gradient along the surface of the retaining material. Advantageously, as mentioned above, this may produce a consistent aerosol with a desired composition. Alternatively, or additionally, this location of the air intake and air outlet may provide predictable fluctuations in the temperature of the air within the aerosol generating system, and thus the heater assembly may be maintained at a desired non-uniform temperature.

[0043] The air in the airflow path preferably passes across the surface of the retaining material. The heater assembly preferably provides a temperature gradient along the surface of the retaining material.

[0044] When in use, this may increase the temperature of the airflow at the air outlet. Some users may prefer this. This may more accurately mimic the experience of smoking a traditional cigarette or cigar.

[0045] The cartridge may be configured to engage with and disengage from the aerosol generator. The aerosol generator may include a power supply. The power supply may be configured to supply power to the heating element. The power supply may be configured to supply power to the heating element only when the cartridge is engaged with the aerosol generator.

[0046] The cartridge may be equipped with a mouthpiece. The mouthpiece may be equipped with an air outlet. When the cartridge is engaged with the aerosol generator during use, the user may inhale through the mouthpiece of the cartridge. This may cause air to flow through the air intake, then across the heater assembly or heating element, over it, past it, or through it, and then through the air outlet.

[0047] The cartridge may have a first electrical contact and a second electrical contact electrically connected to the heating element. The electrical contact may contain one or more of the following: tin, silver, gold, copper, aluminum, steel such as stainless steel, phosphor bronze, tin alloyed with antimony, tin alloyed with zirconium, tin alloyed with bismuth, or tin alloyed with other components that improve resistance to organic acids.

[0048] The electrical contacts may be configured to form an electrical connection with the corresponding electrical contacts on the aerosol generator when the cartridge is engaged with the aerosol generator.

[0049] The heating element may be located within the airflow path between the air intake and air outlet of the cartridge.

[0050] According to another aspect of this disclosure, an aerosol generating system is provided. The aerosol generating system may include the heater assembly of this disclosure.

[0051] The aerosol generating system preferably includes an air intake and an air outlet, and the airflow path may be defined between the air intake and the air outlet. The air drawn from the air intake to the air outlet preferably flows across, past, or through the heating element. The air intake may be located closest to the portion of the heating element having substantially the lowest electrical resistance. The air outlet may be located closest to the portion of the heating element having substantially the highest electrical resistance. The air in the airflow path preferably passes across the surface of the retaining material, and the airflow path is in fluid contact with the aerosol forming substrate. The heater assembly preferably provides a temperature gradient across the surface of the retaining material.

[0052] Advantageously, aerosol generating systems may improve control over the vaporization of different compounds of the liquid aerosol-forming substrate. Aerosol generating systems may result in the simultaneous vaporization of liquid aerosol-forming substrate compounds with higher and lower boiling points at a desired rate. Aerosol generating systems may result in the vaporization of liquid aerosol-forming substrate compounds with higher and lower boiling points in a more favorable ratio. Aerosol generating systems may provide the generation of aerosols with a more desirable composition. Aerosol generating systems may provide more consistent generation of aerosols with desirable properties.

[0053] The aerosol generating system may be equipped with a mouthpiece at the air outlet. The aerosol generating system may also be an e-cigarette system.

[0054] The aerosol generating system may include the cartridge according to this disclosure.

[0055] The system may include an aerosol generator. The system may also include a cartridge with a heater assembly.

[0056] The cartridge may be configured to engage with the aerosol generator. The cartridge may also be configured to engage with and disengage from the aerosol generator.

[0057] An aerosol generating system, such as an aerosol generator in an aerosol generating system, may be equipped with a power source such as a battery. The power source may be configured to supply power to a heating element, which may be for heating the heating element. The power source may be configured to supply power to the heating element only when the cartridge is engaged with the aerosol generator.

[0058] The aerosol generator may include a controller. The controller may be configured to control the supply of power from the power source. Therefore, the controller may control the heating of the heating element.

[0059] The power supply may be configured to supply power to the heating element in order to resistively heat it. The power supply may be configured to supply power to the heating element in order to inductively heat it.

[0060] The aerosol generator may be configured to engage with and disengage from a cartridge via a snap-fit ​​connection, corresponding threads, or any other suitable means. The aerosol generator may be configured to receive at least a portion of the cartridge. For example, the aerosol generator may include a chamber configured to receive at least a portion of the cartridge.

[0061] The aerosol generator may be equipped with an air intake. The aerosol generator may be equipped with an air outlet. When the aerosol generator is engaged with the cartridge, the air outlet of the aerosol generator may be in fluid communication with the air intake of the cartridge.

[0062] A power supply may be electrically connected to the first and second electrical contacts of the device. These first and second electrical contacts may be configured to form an electrical connection with the corresponding first and second electrical contacts on the cartridge when the cartridge is engaged with the device. These corresponding first and second electrical contacts on the cartridge may be electrically connected to a heating element. Therefore, the power supply may be configured to supply power to the heating element by passing an electric current through it.

[0063] Another aspect of the present disclosure provides a method for heating a liquid aerosol-forming substrate in a heater assembly used in an aerosol-generating system. The heater assembly may comprise a liquid aerosol-forming substrate comprising at least two compounds, the first compound having a first boiling point, and the second compound having a second boiling point. The heater assembly may have a holding material containing the aerosol-forming substrate. A heating element may be configured to heat the holding material. The heating element may be formed from a strip of material, the cross-sectional area of ​​the strip of material may decrease progressively along the length of the strip of material. The method may include passing an electric current along the length of the strip of material, thereby providing a temperature gradient along the surface of the holding material.

[0064] Advantageously, this method may improve the control of vaporization of different compounds in the liquid aerosol-forming substrate. A method for heating the liquid aerosol-forming substrate may result in the simultaneous vaporization of liquid aerosol-forming substrate compounds having higher and lower boiling points at a desired rate. A method for heating the liquid aerosol-forming substrate may result in the vaporization of liquid aerosol-forming substrate compounds having higher and lower boiling points in a more favorable ratio. A heater assembly may provide the generation of aerosols with a more desirable composition. A heater assembly may provide more consistent generation of aerosols with desirable properties.

[0065] The strip of material itself may be folded to provide at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of material. The strip of material may have a cross-sectional area that decreases progressively along the length of the strip of material. The width of the strip of material may decrease progressively. Alternatively, or additionally, the thickness of the strip of material may decrease progressively.

[0066] As explained above, at least one overlapping portion may provide a portion of the material strip at a lower temperature than adjacent non-overlapping portions of the material strip. Advantageously, the folding of the material strip itself and the resulting at least one overlapping portion may create a larger area of ​​higher temperature and a larger area of ​​lower temperature along the surface of the retaining material. Alternatively, or additionally, this may provide a larger area of ​​faster temperature rise and a larger area of ​​slower temperature rise along the surface of the retaining material. This may lead to the simultaneous vaporization at a favorable rate of liquid aerosol-forming substrate compounds having higher and lower boiling points. Advantageously, the production of a heating element formed from a folded material strip may enable a simple manufacturing process.

[0067] According to another aspect of the present disclosure, a heater assembly for use in an aerosol generating system is provided. The heater assembly comprises a liquid aerosol-forming substrate comprising at least two compounds, wherein the first compound has a first boiling point and the second compound has a second boiling point; a holding material containing the aerosol-forming substrate; and a heating element configured to heat the holding material, the heating element being formed from a strip of material, wherein the strip of material itself is folded to provide at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of material, thereby providing a temperature gradient along the surface of the holding material.

[0068] As used herein, the term “aerosol” refers to the dispersion of solid particles, or droplets, or combinations of solid particles and droplets, in a gas. Aerosols may be visible or invisible. Aerosols may include vapors of substances that are normally liquid or solid at room temperature, as well as solid particulate matter, or droplets, or combinations of solid particulate matter and droplets.

[0069] As used herein, the term “aerosol-forming substrate” refers to a substrate having the ability to release volatile compounds that can form aerosols. The volatile compounds may be released by heating or burning the aerosol-forming substrate.

[0070] The aerosol-forming substrate may contain multiple compounds. The compounds may have different boiling points. For example, the aerosol-forming substrate may contain a first compound having a first boiling point at atmospheric pressure and a second compound having a second boiling point at atmospheric pressure, where the first boiling point is higher than the second boiling point.

[0071] The aerosol-forming substrate may include an aerosol-forming compound. As used herein, the term “aerosol-forming compound” refers to any suitable compound or mixture of compounds that facilitates the formation of an aerosol, for example, a stable aerosol that is substantially resistant to thermal decomposition at the operating temperature of the system, when used. Suitable aerosol-forming compounds are well known in the art and include, but are not limited to, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (e.g., glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (e.g., dimethyl dodecanediol, dimethyl tetradecanediol).

[0072] The aerosol-forming substrate may contain nicotine. The aerosol-forming substrate may contain water. The aerosol-forming substrate may contain glycerol (also called glycerin), which has a higher boiling point than nicotine. The aerosol-forming substrate may contain plant-derived materials. The aerosol-forming substrate may contain homogenized plant-derived materials. The aerosol-forming substrate may contain tobacco. The aerosol-forming substrate may contain tobacco-containing materials. The tobacco-containing materials may contain volatile tobacco-flavoring compounds. These compounds may be released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may contain homogenized tobacco materials. The aerosol-forming substrate may contain other additives and components such as flavoring agents.

[0073] As used herein, the term “liquid aerosol-forming substrate” refers to an aerosol-forming substrate in a condensed form. Therefore, the “liquid aerosol-forming substrate” may be one or more of a liquid, gel, or paste, or may contain one or more of these. If the liquid aerosol-forming substrate is a gel or paste, or contains a gel or paste, the gel or paste may liquefy upon heating. For example, the gel or paste may liquefy upon heating to temperatures below 50, 75, 100, 150, or 200 degrees Celsius.

[0074] As used herein, the term “heating element” refers to an element of a heater, which is configured to be heated. For example, the term “heating element” may refer to an element configured to be heated to at least 50, 100, 150, 200, 250, or 300 degrees Celsius. The heating element, or a part thereof, may be configured to be resistively heated.

[0075] As used herein, the term “embedded” may be used to mean being surrounded, wrapped, enclosed, enclosed, or enclosed.

[0076] As used herein, the term “length” refers to the primary dimension in the longitudinal direction of an aerosol generating system or a component of an aerosol generating system (such as a strip of material used to form a heating element).

[0077] The boiling point of a liquid is the temperature at which its vapor pressure is equal to the external pressure surrounding it. As used herein, the term “boiling point” refers to the ordinary boiling point or atmospheric pressure boiling point, which is the temperature at which the vapor pressure of a liquid is equal to the pressure at sea level (1 atmosphere).

[0078] As used herein, the term “transverse direction” refers to a direction perpendicular to the longitudinal axis at a specific location along its length. Any reference to “cross section” of an aerosol generating system or its components (such as a heater assembly), or of a heating element component, refers to a cross section unless otherwise specified.

[0079] The present invention is defined in the claims. However, a non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of other embodiments, forms, or aspects described herein.

[0080] Example 1: A heater assembly for use in an aerosol generating system, comprising: a liquid aerosol forming substrate comprising at least two compounds, wherein the first compound has a first boiling point and the second compound has a second boiling point; a holding material containing the liquid aerosol forming substrate; and a heating element configured to heat the holding material by passing an electric current along the length of the heating element, wherein the heating element is formed from a strip of material, and the cross-sectional area of ​​the strip of material gradually decreases along the length of the strip of material, thereby providing a temperature gradient along the surface of the holding material. Example 2: The heater assembly according to Example 1, wherein the strip of material is folded in itself to provide at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of material. Example 3: A heater assembly according to Example 1 or Example 2, wherein the heating element comprises a first heating element material and a second heating element material, the first heating element material being in a first position along the length of the material strip and the second heating element material being in a second position along the length of the material strip. Example 4: The heater assembly according to Example 3, wherein the first heating element material has a first electrical resistivity, and the second heating element material has a second electrical resistivity different from the first electrical resistivity. Example 5: A heater assembly according to any of Examples 1 to 4, comprising multiple heating elements. Example 6: The heater assembly according to Example 5, wherein at least one heating element provides a temperature gradient along the surface of the holding material. Example 7: A heater assembly according to either Example 5 or Example 6, wherein a section of the retaining material is enclosed or partially enclosed within a volume defined between two heating elements. Example 8: A heater assembly according to any of Examples 1 to 7, wherein the heating element is in contact with the holding material. Example 9: A heater assembly according to any of Examples 1 to 8, wherein the heating element is configured to be resistively heated. Example 10: A heater assembly according to any of Examples 1 to 9, wherein the material strip is perforated. Example 11: A heater assembly according to any of Examples 1 to 9, wherein the material strip is a mesh. Example 12: A heater assembly according to any of Examples 1 to 11, wherein the holding material is a porous material. Example 13: A heater assembly according to any of Examples 1 to 12, wherein the holding material is a ceramic material. Example 14: A heater assembly according to any of Examples 1 to 13, wherein the retaining material is a capillary retaining material. Example 15: A heater assembly according to any of Examples 1 to 14, wherein the aerosol-forming substrate is absorbed into the holding material. Example 16: A heater assembly according to any of Examples 1 to 15, wherein the minimum cross-sectional area along the length of the material strip is at least 10% less than the maximum cross-sectional area along the length of the material strip. Example 17: A heater assembly according to any of Examples 1 to 16, wherein the boiling point of the first compound is 240°C to 250°C. Example 18: A heater assembly according to any of Examples 1 to 17, wherein the boiling point of the second compound is 285 degrees Celsius to 295 degrees Celsius. Example 19: A cartridge for use in an aerosol generation system, comprising a heater assembly according to any of Examples 1 to 18. Example 20: The cartridge according to Example 19, further comprising an air intake and an air outlet, wherein the airflow path is defined between the air intake and the air outlet. Example 21: The cartridge according to Example 20, wherein the air drawn from the air intake to the air outlet flows across, past, or through the heating element. Example 22: The cartridge according to Example 21, wherein the air intake is located closest to the portion of the heating element having substantially the lowest electrical resistance. Example 23: The cartridge according to Examples 20-22, wherein the air outlet is located closest to the portion of the heating element having substantially the highest electrical resistance. Example 24: A cartridge according to any of Examples 20-23, wherein the air in the airflow path passes across the surface of the retaining material. Example 25: A cartridge according to any of Examples 20-24, wherein the heater assembly provides a temperature gradient across the surface of the retaining material. Example 26: An aerosol generating system comprising a heater assembly described in any of Examples 1 to 25. Example 27: The aerosol generating system according to Example 26, further comprising an air intake and an air outlet, wherein the airflow path is defined between the air intake and the air outlet. Example 28: The aerosol generating system according to Example 27, wherein the air drawn from the air intake to the air outlet flows across, past, or through a heating element. Example 29: The aerosol generating system according to either Example 27 or Example 28, wherein the air intake is located closest to the portion of the heating element having substantially the lowest electrical resistance. Example 30: The aerosol generating system according to either Example 27 or Example 28, wherein the airflow path outlet is located closest to the portion of the heating element having substantially the highest electrical resistance. Example 31: An aerosol generation system according to any one of Examples 26 to 30, wherein air in the airflow path passes across the surface of the holding material, and the airflow path is in fluid contact with the aerosol-forming substrate. Example 32: An aerosol generating system according to any of Examples 26-31, wherein the heater assembly provides a temperature gradient across the surface of the holding material. Example 33: An aerosol generating system according to any one of Examples 27 to 32, further comprising a mouthpiece at the air outlet. Example 34: The aerosol generating system according to any one of Examples 26 to 33, wherein the aerosol generating system is an e-cigarette system. Example 35: A method for heating an aerosol-forming substrate in a heater assembly used in an aerosol generating system, the heater assembly comprising: a liquid aerosol-forming substrate comprising at least two compounds, wherein the first compound has a first boiling point and the second compound has a second boiling point; a holding material containing the aerosol-forming substrate; and a heating element configured to heat the holding material, wherein the heating element is formed from a strip of material, the cross-sectional area of ​​the strip of material decreasing progressively along the length of the strip of material, the method comprising passing an electric current along the length of the strip of material, thereby providing the heating element with a temperature gradient along the surface of the holding material. Example 36: The method according to Example 35, wherein the strip of material is folded in itself and provides at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of material. Example 37: A heater assembly for use in an aerosol generating system, comprising: a liquid aerosol forming substrate comprising at least two compounds, wherein the first compound has a first boiling point and the second compound has a second boiling point; a holding material containing the aerosol forming substrate; and a heating element configured to heat the holding material, the heating element being formed from a strip of material, wherein the strip of material itself is folded to provide at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of material, thereby providing a temperature gradient along the surface of the holding material.

[0081] Here, we will further describe the examples with reference to the following figures. [Brief explanation of the drawing]

[0082] [Figure 1] Figure 1 shows a cross-sectional view along the long axis of the first aerosol generating system, which includes a cartridge equipped with a first heater assembly. [Figure 2] Figure 2 shows a cross-sectional view of the first heater assembly. [Figure 3] Figure 3 shows a cross-sectional view of the second heater assembly. [Figure 4] Figure 4 shows a cross-sectional view of the third heater assembly. [Modes for carrying out the invention]

[0083] Figure 1 shows a cross-sectional view of the aerosol generating system 100 along its long axis. The aerosol generating system 100 comprises an aerosol generator 150 and a cartridge 200. In this embodiment, the aerosol generating system 100 is an electrically operated smoking system, often referred to as an e-cigarette system.

[0084] The aerosol generator 150 is portable and is comparable in size to a conventional cigar or cigarette. The device 150 includes a battery 152, such as a lithium iron phosphate battery, and a controller 154 electrically connected to the battery 152. The device 150 also includes two electrical contacts 156 and 158 electrically connected to the battery 152. This electrical connection is wired and is not shown in Figure 1.

[0085] The cartridge 200 comprises a first electrical contact 214, a second electrical contact 216, an air intake 202, an air outlet 204, and a heater assembly 300. The airflow path is defined between the air intake 202 and the air outlet 204. The heater assembly 300 is located downstream of the air intake 202 and upstream of the air outlet 204. The heater assembly 300 comprises a liquid aerosol forming substrate, a retaining material 302, and a storage section 303 for the liquid aerosol forming substrate. The retaining material 302 is in fluid communication with the storage section 303 for the liquid aerosol forming substrate. The heater assembly 300 also comprises a heating element 304. The first electrical contact 214 and the second electrical contact 216 are electrically connected to the heating element 304.

[0086] In this system 100, the liquid aerosol-forming substrate contains approximately 74% by weight of glycerin, 24% by weight of propylene glycol, and 2% by weight of nicotine, but any suitable substrate can be used. At atmospheric pressure, nicotine has a boiling point of approximately 247 degrees Celsius, glycerin has a boiling point of approximately 290 degrees Celsius, and propylene glycol has a boiling point of approximately 188 degrees Celsius. Therefore, when this liquid aerosol-forming substrate is initially heated to form an aerosol, some systems may unnecessarily vaporize a disproportionately large amount of propylene glycol (which has the lowest boiling point among the compounds forming the substrate). This may lead to the delivery of less desirable aerosols to the user, such as aerosols containing a lower-than-desired proportion of nicotine. This may also unnecessarily change the relative ratios of the compounds in the substrate over a longer period of time. The present invention may eliminate or at least reduce these undesirable effects.

[0087] The heating element 304 is configured to heat the holding material 302 by passing an electric current along the length of the heating element 304. The heating element 304 is formed from a strip of material. The strip of material has a cross-sectional area that gradually decreases along the length of the strip. The decreasing cross-sectional area of ​​the strip of material provides a temperature gradient along the surface of the holding material 302.

[0088] In this embodiment, the material is mesh-formed stainless steel. The strip of material may be perforated.

[0089] In this embodiment, the retaining material 302 is a porous ceramic capillary retaining material having numerous pores. In Figure 1, the aerosol-forming substrate is absorbed into the retaining material 302. The aerosol-forming substrate is stored within the pores of the porous ceramic material.

[0090] In this embodiment, the storage section 303 for the liquid aerosol-forming substrate includes a capillary material having a fibrous structure. In other embodiments, a storage section or tank for the liquid aerosol-forming substrate may be used. The capillary material is made of polyester.

[0091] The storage portion 303 of the liquid aerosol-forming substrate may be attached to the holding material 302 with adhesive, or held in place by friction, or held in place by other suitable means.

[0092] In Figure 1, the aerosol generator 150 is engaged with the cartridge 200. In this embodiment, the cartridge 200 is engaged with the aerosol generator 150 via threads 206 of the cartridge 200 that are fitted with the corresponding threads 162 of the aerosol generator 150.

[0093] During use, the user inhales smoke from the air outlet 204 of the cartridge 200. Simultaneously, the user presses a button (not shown) on the aerosol generator 150. Pressing this button sends a signal to the controller 154, which results in power being supplied from the battery 152 to the heating element 304 via the electrical contacts 156, 158 of the device and the electrical contacts 214, 216 of the cartridge. This causes current to flow through the heating element 304, thereby resistively heating it. In other embodiments, an airflow sensor or pressure sensor is located inside the cartridge 200 and electrically connected to the controller 154. The airflow sensor or pressure sensor detects that the user is inhaling smoke from the air outlet 204 of the cartridge 200 and sends a signal to the controller 154 to provide power to the heating element 304. Thus, in these embodiments, the user does not need to press a button to heat the heating element 304.

[0094] As the heating element 304 is resistively heated, areas of higher temperature and areas of lower temperature are created along the surface of the retaining material 302. Areas of lower temperature may be created in areas where the strip of material on which the heating element 304 is formed has a larger cross-sectional area. Creating areas of higher and lower temperature simultaneously vaporizes compounds of the liquid aerosol-forming substrate in the retaining material 302 that have higher and lower boiling points. In this embodiment, although not shown in Figure 1, the air intake is located near the portion of the heating element with substantially the lowest electrical resistance. The air outlet is located closest to the portion of the heating element with substantially the highest electrical resistance.

[0095] As the user draws air into the air outlet 204 of the cartridge 200, air is drawn into the air intake 202. This air then travels across the heater assembly 300 and across the surface of the retaining material 302 toward the air outlet 204. This airflow entrains vapor formed by heating the liquid aerosol-forming substrate within the retaining material 302 by the heating element 304. This entrained vapor then cools and condenses, forming an aerosol. This aerosol is then delivered to the user via the air outlet 204. As the liquid aerosol-forming substrate in the retaining material 302 is heated, vaporized, and entrained in the airflow, the liquid aerosol-forming substrate from the storage unit 303 moves into the retaining material 302. This aerosol-forming substrate from the storage unit 303 substantially replaces the vaporized aerosol-forming substrate. The liquid aerosol-forming substrate from the storage unit 303 may also be drawn into the retaining material 302 by capillary action, at least partially. This is because the retaining material 302 is a capillary material having a fibrous or spongy structure.

[0096] Figure 2 shows a cross-sectional view of the heater assembly 300. The heating element 304 is formed from a strip of material. The cross-sectional area of ​​the material strip gradually decreases along the length of the material strip to provide a temperature gradient along the surface of the material. The heating element 304 is electrically connected to electrical contacts (not shown in Figure 2) configured to supply power to resistively heat the heating element 304. In Figure 2, the width of the material strip of the heating element 304 gradually decreases. The minimum width of the heating element 304 is approximately 50 percent of the maximum width of the heating element. Therefore, the electrical resistance of the heating element increases as the width of the material strip decreases, providing a temperature gradient along the surface of the holding material 302.

[0097] Figure 3 shows a cross-sectional view of the second heater assembly 600. The heating elements 604 and 605 are formed from strips of material. The heating elements 604 and 605 are configured to heat the retaining material 602. During use, an electric current is passed along the length of the heating elements 604 and 605. Each heating element 604 and 605 is formed from a strip of material. The strip of material has a cross-sectional area that gradually decreases along the length of the strip. The decreasing cross-sectional area of ​​the strip of material provides a temperature gradient along the surface of the retaining material 602. The heating elements 604 and 605 are partially embedded within the retaining material 602. Thus, a section of the retaining material 602 is partially enclosed within a volume defined between the two heating elements 604 and 605. The heating elements 604 and 605 are electrically connected to electrical contacts not shown in Figure 3, which are configured to supply power to resistively heat the heating elements 604 and 605. As the heating elements 604 and 605 are resistively heated, areas of higher and lower temperatures are created within the retaining material 602. Areas of lower temperatures may be created in areas where the strips of material on which the heating elements 604 and 605 are formed have a larger cross-sectional area. In addition, since the section of the retaining material 602 is enclosed within a defined volume between the two heating elements 604 and 605, the heating elements are positioned to further increase the temperature gradient as needed. For example, in Figure 3, the heating elements 604 and 605 are positioned such that the area of ​​the strip of material with the smallest cross-sectional area is located closer together than the edges of the strips of material with larger cross-sectional areas. This provides an increased temperature gradient across the surface of the retaining material 602.

[0098] Creating areas of higher and lower temperatures simultaneously vaporizes the liquid aerosol-forming substrate compounds having higher and lower boiling points within the liquid aerosol-forming substrate storage component 602.

[0099] Figure 4 shows a cross-sectional view of the fourth heater assembly 900. The heating element 904 is formed from a strip of material. The strip of material itself is folded to provide at least one overlapping portion of the strip of material. This provides a portion of the heating element 915 that has a greater thickness than the adjacent portions of the heating elements 905, 925. The portion of the heating element 915 having greater thickness also has a lower electrical resistance than the adjacent non-overlapping portions 905, 925 of the strip of material. The heating element 904 is electrically connected to electrical contacts not shown in Figure 4, which are configured to supply power to resistively heat the heating element 904. In use, the portion of the heating element 915 with lower electrical resistance is at a lower temperature and therefore provides less heat to the retaining material than the adjacent non-overlapping portions 905, 925 of the retaining material. As a result, the heating element 904 provides a temperature gradient along the surface of the retaining material. The cooler portions along the retaining material correspond to the portion of the heating element 915 having greater thickness.

[0100] Additionally, the material strip in Figure 4 has a cross-sectional area that gradually decreases along the length of the material strip. The width of the material strip gradually decreases, providing a temperature gradient along the length of the material strip. In Figure 4, nine parts of the material strip overlap, but any number of overlapping parts may be selected. As a result, the heating element does not have a gradually decreasing cross-sectional area.

[0101] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., should be understood in all cases as being modified by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein. Thus, in this context, the number A is understood as A ± 10 percent. In this context, the number A may be considered to include a number that falls within the general standard error of the measurement of the characteristic that the number A modifies. In some cases as used in the appended claims, the number A may deviate by the percentage listed above, provided that the amount of deviation does not substantially affect the basic and novel characteristics(s) of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges therewith, which may or may not be specifically listed herein.

Claims

1. A heater assembly used in an aerosol generation system, A liquid aerosol-forming substrate comprising at least two compounds, wherein the first compound has a first boiling point and the second compound has a second boiling point, A holding material containing the liquid aerosol forming substrate, A heater assembly comprising: a heating element configured to heat the retaining material by passing an electric current along the length of the heating element, wherein the heating element is formed from a strip of material, and the cross-sectional area of ​​the strip of material gradually decreases along the length of the strip of material from the maximum cross-sectional area of ​​the strip of material at a first end of the strip of material to the minimum cross-sectional area of ​​the strip of material at a second end of the strip of material, thereby providing a temperature gradient along the surface of the retaining material.

2. The heater assembly according to claim 1, wherein the strip of the material is itself folded and provides at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of the material.

3. The heater assembly according to claim 1 or 2, wherein the heating element comprises a first heating element material and a second heating element material, the first heating element material is located at a first position along the length of the strip of the material, the second heating element material is located at a second position along the length of the strip of the material, the first heating element material has a first electrical resistivity, and the second heating element material has a second electrical resistivity different from the first electrical resistivity.

4. A heater assembly according to any one of claims 1 to 3, comprising a plurality of heating elements, wherein at least one heating element provides a temperature gradient along the surface of the holding material.

5. The heater assembly according to any one of claims 1 to 4, wherein the strip of the material is perforated or is a mesh.

6. The heater assembly according to any one of claims 1 to 5, wherein the retaining material is a porous ceramic capillary retaining material.

7. A cartridge for use in an aerosol generating system, comprising a heater assembly according to any one of claims 1 to 6.

8. The cartridge according to claim 7, comprising an air intake and an air outlet, wherein an airflow path is defined between the air intake and the air outlet, and the air drawn from the air intake to the air outlet flows across, past, or through the heating element.

9. The cartridge according to claim 8, wherein the air intake is located closest to the portion of the heating element having substantially the lowest electrical resistance, and the air outlet is located closest to the portion of the heating element having substantially the highest electrical resistance.

10. An aerosol generating system comprising a heater assembly according to any one of claims 1 to 6.

11. The aerosol generating system according to claim 10, comprising an air intake and an air outlet, wherein an airflow path is defined between the air intake and the air outlet, and the air drawn from the air intake to the air outlet flows across, past, or through the heating element.

12. The aerosol generating system according to claim 11, wherein the air intake is located closest to the portion of the heating element having substantially the lowest electrical resistance, and the air outlet is located closest to the portion of the heating element having substantially the highest electrical resistance.

13. The aerosol generating system according to claim 11 or claim 12, wherein the air in the airflow path passes across the surface of the holding material, and the airflow path is in fluid contact with the liquid aerosol forming substrate.

14. A method for heating an aerosol-forming substrate in a heater assembly used in an aerosol generation system, wherein the heater assembly is A liquid aerosol-forming substrate comprising at least two compounds, wherein the first compound has a first boiling point and the second compound has a second boiling point, A retaining material containing the aerosol-forming substrate, A heating element configured to heat the holding material, wherein the heating element is formed from a strip of material, and the cross-sectional area of ​​the strip of material gradually decreases along the length of the strip of material, The method comprises passing an electric current along the length of a strip of the material, thereby providing a heating element with a temperature gradient along the surface of the retaining material.

15. The method according to claim 14, wherein the strip of the material is itself folded and provides at least one overlapping portion having a greater thickness and lower electrical resistance than adjacent non-overlapping portions of the strip of the material.

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