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WO2024200748A1 - Ensemble dispositif de chauffage à corps poreux - Google Patents

Ensemble dispositif de chauffage à corps poreux Download PDF

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Publication number
WO2024200748A1
WO2024200748A1 PCT/EP2024/058648 EP2024058648W WO2024200748A1 WO 2024200748 A1 WO2024200748 A1 WO 2024200748A1 EP 2024058648 W EP2024058648 W EP 2024058648W WO 2024200748 A1 WO2024200748 A1 WO 2024200748A1
Authority
WO
WIPO (PCT)
Prior art keywords
porous body
aerosol
heating element
heating
heater assembly
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/058648
Other languages
English (en)
Inventor
Jérôme Christian COURBAT
Leander Dittmann
Ross Peter Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Philip Morris Products SA
Original Assignee
Philip Morris Products SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Philip Morris Products SA filed Critical Philip Morris Products SA
Priority to CN202480018574.3A priority Critical patent/CN120936260A/zh
Publication of WO2024200748A1 publication Critical patent/WO2024200748A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
    • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
    • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
    • A24F40/44—Wicks
    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
    • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
    • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
    • A24F40/46—Shape or structure of electric heating means
    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
    • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
    • A24F40/10—Devices using liquid inhalable precursors

Definitions

  • the present invention relates to a heater assembly for use in an aerosol-generating system.
  • the present invention relates to a heater assembly for use in an aerosolgenerating system, the heater assembly comprising a heating element and a porous body.
  • Aerosol-generating systems that heat a liquid aerosol-forming substrate in order to generate an aerosol for delivery to a user are generally known in the prior art. These systems typically comprise an aerosol-generating device and a replaceable cartridge.
  • the cartridge includes a liquid aerosol-forming substrate that is capable of releasing volatile compounds when heated.
  • the cartridge typically also includes a heater for heating the liquid aerosolforming substrate.
  • the heater comprises a resistive heating element wound around a wick that supplies liquid aerosol-forming substrate to the heating element.
  • the aerosol-generating device or cartridge also comprises a mouthpiece.
  • Such known aerosol-generating systems have a number of drawbacks. There is a need to prevent “dry heating” or a “dry puffing”, which arises when the heating element is heated with insufficient liquid aerosol-forming substrate being supplied to the heating element. During operation, it is preferable to maintain a supply of liquid aerosol-forming substrate to the heating element such that the heating element is maintained in a wet state because this helps to ensure that a satisfactory aerosol is produced when a user takes a puff. Dry heating can result in overheating of the heating element and, potentially, thermal decomposition of the liquid aerosol-forming substrate, which can produce undesirable by-products and an unsatisfactory aerosol. Allowing the aerosol-generating system to continue to operate when liquid aerosol-forming substrate is not being supplied to the heating element can result in a poor user experience.
  • aerosol-generating systems of the prior art may leak liquid aerosol-forming substrate.
  • liquid aerosol-forming substrate may leak out of one end of the wick and out of the system. This is both a waste of aerosol-forming substrate and can contaminate other components of the aerosol-generating system. Leakage of liquid aerosol-forming substrate is therefore undesirable. It would be desirable to provide a heater assembly in which efficient and consistent supply of liquid aerosol-forming substrate to the heating element is provided.
  • a heater assembly for an aerosol-generating system.
  • the heater assembly may comprise a heating element for vaporising a liquid aerosol-forming substrate.
  • the heater assembly may comprise a porous body for conveying the liquid aerosol-forming substrate to the heating element.
  • the porous body may have a liquid absorption surface.
  • the porous body may have a heating surface.
  • the heating element may be located on the heating surface of the porous body.
  • the heating element and the porous body may be integrally formed.
  • the heating element and the porous body may be formed as a single monolithic piece. The average pore size of the porous body may vary between the liquid absorption surface and the heating surface.
  • a heater assembly for an aerosol-generating system.
  • the heater assembly comprises a heating element for vaporising a liquid aerosol-forming substrate.
  • the heater assembly comprises a porous body for conveying the liquid aerosol-forming substrate to the heating element.
  • the porous body has a liquid absorption surface.
  • the porous body has a heating surface.
  • the heating element is located on the heating surface of the porous body.
  • the heating element and the porous body is integrally formed. The average pore size of the porous body varies between the liquid absorption surface and the heating surface.
  • a porous body which includes a variation of pore size between the liquid absorption surface and the heating surface may advantageously help to control the transport of liquid aerosol-forming substrate from a reservoir of liquid aerosol-forming substrate to the heating element.
  • the variation of pore size between the liquid absorption surface and the heating surface may allow the porous body to provide a consistent supply of aerosol-forming substrate to the heating surface. This may advantageously avoid undesirable “dry heating”.
  • the porous body of the present invention may also advantageously prevent leakage of liquid aerosol-forming substrate from the heating surface of the porous body.
  • the provision of the heating element being integrally formed with the porous body may advantageously provide a more robust and reliable connection between the heating element and the porous body. This may advantageously help to improve the transfer of heat between the heating element and the porous body.
  • Forming the heating element integrally with the porous body may also advantageously provide a heating element which is easier to reliably manufacture, thus resulting in a more energy efficient heating element capable of generating a more consistent aerosol. This, in turn, may provide a user of the aerosol-generating system with an improved and more enjoyable experience. Such an arrangement may also help to reduce the likelihood of a user experiencing dry heating or a dry puff.
  • An advantage of forming the heating element integrally with the porous body is that it helps to alleviate the problems of manufacturing tolerances encountered with wick and coil heaters and other arrangements in which a heating element is detached from a liquid transport element.
  • the dimensions and arrangement of the heating element relative to the porous body are also fixed, which helps to produce a more consistent aerosol. This is because the heating element is fixed to the porous body, which helps to supply liquid aerosol-forming substrate to the heating element. This also helps to prevent unwanted loss of heat, which helps to improve energy efficiency.
  • the resulting aerosolgenerating system may benefit from reduced material requirements. This is because the need for intermediate components which fix the heating element relative to the porous body can be reduced or eliminated entirely. The material savings can result in cost savings of the overall aerosol-generating system.
  • An additional advantage of the reduced material requirements in the overall aerosol-generating system is the provision of a more sustainable and environmentally friendly solution.
  • the heating surface of the porous body may not be a clearly defined surface.
  • the porous body and the heating element may be made from a single monolithic portion of porous material. Where this is the case, the heating element may be a portion of the porous material which has been configured to generate heat. As described in more detail below, this may be achieved by, for example, doping a portion of the porous material or diffusing electrically conductive material into the porous material. Accordingly, the heating surface of the porous body may represent the interface between the portion of the porous material which is configured to transport liquid aerosol-forming substrate, and a portion of the porous material which is configured to generate heat. Depending on how the heating element is formed, the heating surface of the porous body may be a gradual interface between the portion of the porous material which is configured to transport liquid aerosol-forming substrate, and a portion of the porous material which is configured to generate heat.
  • the porous body may have any porosity.
  • the porosity of the porous body may be substantially constant between the liquid absorption surface and the heating surface.
  • the porosity of the porous body may vary between the liquid absorption surface and the heating surface.
  • the porosity of the porous body may be greater at the liquid absorption surface compared to the heating surface.
  • the porosity of the porous body at the liquid absorption surface may be at least 20 percent.
  • the porosity of the porous body at the liquid absorption surface may be at least 30 percent, at least 40 percent.
  • the porosity of the porous body at the liquid absorption surface may be no more than 100 percent.
  • the porosity of the porous body at the liquid absorption surface may be no more than 90 percent, no more than 80 percent, no more than 70 percent, no more than 60 percent.
  • the porosity of the porous body at the liquid absorption surface may be between 20 percent and 90 percent.
  • the porosity of the porous body at the liquid absorption surface may be between 30 percent and 80 percent, between 40 percent and 70 percent, or between 40 precent and 60 percent.
  • the porosity of the porous body at the liquid absorption surface may be about 50 percent.
  • the porosity of the porous body at the heating surface may be at least 20 percent.
  • the porosity of the porous body at the heating surface may be at least 30 percent, at least 40 percent.
  • the porosity of the porous body at the heating surface may be no more than 100 percent.
  • the porosity of the porous body at heating surface may be no more than 90 percent, no more than 80 percent, no more than 70 percent, no more than 60 percent.
  • the porosity of the porous body at the heating surface may be between 20 percent and 90 percent.
  • the porosity of the porous body at the heating surface may be between 30 percent and 80 percent, between 40 percent and 70 percent, or between 40 precent and 60 percent.
  • the porosity of the porous body at the heating surface may be about 50 percent.
  • the porous body may have any length.
  • the porous body may have a length of at least 0.5 millimetres.
  • the porous body may have a length of at least 1 millimetre, at least 2 millimetres, at least 3 millimetres, at least 4 millimetres, or at least 5 millimetres.
  • the porous body may have a length of no more than 20 millimetres.
  • the porous body may have a length of no more than 10 millimetres, no more than 9 millimetres, no more than 8 millimetres, no more than 7 millimetres, or no more than 6 millimetres.
  • the porous body may have a length of between 0.5 millimetres and 20 millimetres.
  • the porous body may have a length of between 1 millimetre and 10 millimetres, between 2 millimetres and 9 millimetres, between 3 millimetres and 8 millimetres, between 4 millimetres and 7 millimetres, or between 5 millimetres and 6 millimetres.
  • the porous body may have a length of about 5 millimetres.
  • liquid aerosolgenerating substrate relates to a liquid substrate capable of releasing volatile compounds that can form an aerosol. Such volatile compounds can be released by heating the aerosol-forming substrate.
  • heating element refers to a component which transfers heat energy to the liquid aerosol-generating substrate. It will be appreciated that the electrical heating element may be deposited directly on the porous body. It will be appreciated that the heating element may be a portion of the same porous material from which the porous body is formed.
  • porous body refers to a component which has a plurality of pores, at least some of which are interconnected.
  • the porous body is configured to contain liquid within the plurality of pores.
  • the porous body may comprise a porous material.
  • heating surface refers to the surface of the porous body nearest to the heating element, or on which the heating element is provided.
  • liquid absorption surface refers to the surface of the porous body opposing the heating surface.
  • the liquid absorption surface may be arranged to receive liquid aerosol-forming substrate from a liquid storage portion of reservoir of liquid aerosol-forming substrate.
  • the average pore size of the porous body may vary in any way between the liquid absorption surface and the heating surface.
  • the average pore size may vary from relatively larger pores at the liquid absorption surface to relatively smaller pores at the heating surface.
  • the porous body may include an average pore size gradient between the liquid absorption surface and the heating surface.
  • the average pore size gradient may be a constant average pore size gradient.
  • the average pore size gradient may be a varying average pore size gradient.
  • the average pore size may vary in a step-wise way between the liquid absorption surface and the heating surface.
  • a portion of the porous body including the liquid absorption surface may have a first average pore size
  • the portion of the porous body including the heating surface may include a second average pore size.
  • the first average pore size may be larger than the second average pore size.
  • the porous body may have a heating end and a liquid absorption end, the heating surface being disposed at the heating end, and the liquid absorption surface being disposed at the liquid absorption end.
  • the porous body may have a first average pore size at the liquid absorption end, and a second average pore size at the heating end, first average pore size being greater than the second average pore size.
  • a porous body having a larger average pore size at the liquid absorption end, and a smaller average pore size at a heating end may particularly facilitate efficient transfer of liquid aerosol-forming substrate from the liquid absorption end of the porous body to the heating end of the porous body without allowing leakage.
  • the inventors of the present invention have identified that liquid aerosol-forming substrate is transferred from the liquid absorption end of the porous body to the heating end of the porous body by capillary action.
  • How rapidly the liquid aerosol-forming substrate moves through the porous body depends on a number of factors including, but not limited to, the geometry of the pores, the surface tension between the liquid aerosol-forming substrate and the porous body, the viscosity of the liquid aerosol-forming substrate, the surface tension of the liquid aerosolforming substrate, and the overall geometry of the porous body.
  • the inventors of the present invention have identified the need to balance these factors to provide efficient transfer of liquid aerosol-forming substrate to the heating surface of the porous body while preventing leakage of the liquid aerosol-forming substrate.
  • the capillary pressure in order to provide an efficient capillary flow of liquid through the porous body, the capillary pressure must overcome the viscous drag pressure. Secondly, to prevent leakage, inertial forces must not overcome the capillary pressure.
  • the inventors of the present invention have realised that the viscosity of the liquid aerosol-forming substrate varies with temperature.
  • the viscosity of the liquid aerosol-forming substrate decreases as its temperature increases.
  • the viscosity of the liquid aerosol-forming substrate decreases. Since the liquid aerosol-forming substrate is transported through the porous body by capillary forces, the capillary force needs to overcome the viscous drag of the liquid. The viscous drag decreases as viscosity decreases.
  • the capillary force needed to move the liquid aerosol-forming substrate can decrease towards the heating surface of the porous body while still maintaining the same flow rate. Consequently, the average pore size of the porous body can decrease towards the heating surface without reducing the flow of liquid aerosol-forming substrate through the porous body.
  • the porous body may include pores having any pore size.
  • the first average pore size may be at least 1 micrometre.
  • the first average pore size may be at least 2 micrometres, at least 5 micrometres, at least 10 micrometres, at least 25 micrometres, or at least 50 micrometres.
  • the first average pore size may be no greater than 250 micrometres.
  • the first average pore size may be no greater than 200 micrometres, no greater than 150 micrometres, no greater than 100 micrometres, or no greater than 50 micrometres.
  • the first average pore size may be between 1 micrometre and 250 micrometres.
  • the first average pore size may be between 2 micrometres and 200 micrometres, between 5 micrometres and 150 micrometres, between 10 micrometres and 100 micrometres, or between 25 micrometres and 50 micrometre.
  • the first average pore size may be between 5 micrometres and 200 micrometres.
  • the first average pore size may be between 10 micrometres and 90 micrometres.
  • the second average pore size may be at least 1 micrometre.
  • the second average pore size may be at least 2 micrometres, at least 5 micrometres, at least 10 micrometres, at least 25 micrometres, or at least 50 micrometres.
  • the second average pore size may be no greater than 250 micrometres.
  • the second average pore size may be no greater than 200 micrometres, no greater than 150 micrometres, no greater than 100 micrometres, or no greater than 50 micrometres.
  • the second average pore size may be between 1 micrometre and 250 micrometres.
  • the second average pore size may be between 2 micrometres and 200 micrometres, between 5 micrometres and 150 micrometres, between 10 micrometres and 100 micrometres, or between 25 micrometres and 50 micrometre.
  • the second average pore size may be between 5 micrometres and 200 micrometres.
  • the second average pore size may be between 10 micrometres and 90 micrometres.
  • the first average pore size, at the liquid absorption end of the porous body may be greater than the second average pore size, at the heating end of the porous body.
  • the porous body may comprise a first porous material at the liquid absorption end, and a second porous material at the heating end, the first porous material having the first average pore size, and the second porous material having the second average pore size.
  • the porous body may comprise two adjacent porous materials, the two adjacent porous materials having different pore sizes.
  • the average pore size of the second porous material may be smaller than the average pore size of the first porous material.
  • the first porous material may comprise the same material as the second porous material other than that the first and second porous materials have different porosities.
  • the first and second porous materials may comprise silicon nitride.
  • the first porous material may have any length.
  • the second porous material may have any length.
  • the length of the first porous material may be substantially the same as the length of the second porous material.
  • the length of the second porous material may be greater than the length of the first porous material.
  • the length of the first porous material may be greater than the length of the second porous material.
  • the term “length” refers to the dimension of a component of the heater assembly measured along the longitudinal axis of the heater assembly.
  • the term “longitudinal axis” refers to the axis extending between the liquid absorption surface and the heating surface of the porous body of the heater assembly.
  • liquid aerosolforming substrate is drawn from the liquid absorptions surface of the porous body to the heating surface of the porous body substantially along the longitudinal direction.
  • width denotes the maximum dimension of the heater assembly, a component of the heater assembly, or a part of the heater assembly in a transverse direction.
  • the ratio of the length of the first porous material to the length of the second porous material may be at least 1 .
  • the ratio of the length of the first porous material to the length of the second porous material may be at least 1.5, at least 2, at least 2.5, at least 3, at least 4, or at least 5.
  • the area of the heating surface of the porous body may be substantially the same as the area of the heating element.
  • the heating element may advantageously heat the entire heating surface of the porous body. This may advantageously maximise the aerosolization of the liquid aerosol-forming substrate and may prevent or reduce leakage of the liquid aerosol-forming substrate out of the heating surface of the porous body.
  • the heating element may be any heating element.
  • the heating element may be fluid permeable.
  • the term “fluid permeable” in the context of the heating element means that liquid aerosol-forming substrate is able to pass from one side of the heating element to the other side of the heating element without needing to go around the heating element.
  • the material from which the heating element is made may be fluid permeable.
  • the material from which the heating element is made may be fluid impermeable, but the structure or arrangement of the heating element may nevertheless allow liquid aerosol-forming substrate to pass from one side of the heating element to the other side of the heating element.
  • the heating element may be an electrical heating element.
  • the heating element may be a resistive heating element.
  • the heating element may have any suitable shape or form. Examples of suitable shapes and forms include but are not limited to a band, a strip, a filament, a wire, a mesh, a flat spiral coil, fibres or a fabric.
  • the heating element is planar.
  • the planar heating element may extend substantially in a plane.
  • the heating element comprises a mesh.
  • the heating element may comprise an array of filaments forming a mesh.
  • the term "mesh” encompasses grids and arrays of filaments having spaces therebetween.
  • the term mesh also includes woven and non-woven fabrics.
  • the filaments may be formed by etching a sheet material, such as a foil. This may be particularly advantageous when the heater assembly comprises an array of parallel filaments.
  • the heating element comprises a mesh or fabric of filaments
  • the filaments may be individually formed and knitted together.
  • the heating element may comprise an electrically resistive heating element.
  • the heating element may be made from any suitable electrically conductive material. Suitable materials include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group.
  • suitable metal alloys include stainless steel, constantan, nickel-, cobalt-, chromium-, aluminum-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai®, iron-aluminum based alloys and iron-manganese-aluminum based alloys. Timetai® is a registered trade mark of Titanium Metals Corporation.
  • the heating element may be made from stainless steel, for example, a 300 series stainless steel such as AISI 304, 316, 304L, 316L.
  • the electrical heating element may comprise one of more of NiCr and TiZr.
  • the heating element may comprise combinations of the above materials.
  • a combination of materials may be used to improve the control of the resistance of the heating element.
  • materials with a high intrinsic resistance may be combined with materials with a low intrinsic resistance. This may be advantageous if one of the materials is more beneficial from other perspectives, for example price, machinability or other physical and chemical parameters.
  • high resistivity heating allow more efficient use of battery energy.
  • the electrical heating element may be formed from an electrically conductive material deposited on to the porous body.
  • electrically conductive material denotes a material having a resistivity of 1x10-2 Qm, or less.
  • deposited means applied as a layer or coating by a physical or chemical process, for example in the form of a liquid, plasma or vapour which subsequently condenses or aggregates to form the electrical heating element, rather than simply being laid on or fixed to the porous body as a solid, pre-formed component. In this way, the heating element is integrally formed with the porous body.
  • the electrical heating element may be deposited directly on to the porous outer surface.
  • the electrically conductive material that forms the electrical heating element is deposited onto the porous body such that the electrical heating element is in direct contact with the porous body.
  • the electrically conductive material of the electrical heating element may be at least partially diffused into the porous body.
  • the term “diffused into the porous body” means that the electrically conductive material is interspersed with the material of the porous body at the interface between the electrically conductive material and the porous body, for example, by extending into the pores of the porous body. This arrangement may help to secure the electrical heating element to the porous body and increase contact between the electrical heating element and the porous body to improve heating of the liquid aerosol-forming substrate and aerosol delivery. In this way, the heating element is integrally formed with the porous body.
  • the electrically conductive material from which the electrical heating element is formed may be deposited onto the porous body in any suitable manner.
  • the electrically conductive material may be deposited onto the porous body as a liquid using a dispensing pipette or syringe, or using a fine-tipped transferring device such as a needle.
  • the at least one heating element comprises a printable electrically conductive material printed on the porous body.
  • any suitable known printing technique may be used. For example, one or more of screen-printing, gravure printing, flex-printing, inkjet printing. Such printing processes may be particularly applicable for high speed production processes.
  • the electrically conductive material, from which the electrical heating element is formed may be deposited onto the porous body by one or more vacuum deposition processes, such as evaporation deposition and sputtering.
  • the at least one heating element may be formed from any suitable electrically conductive material.
  • the electrically conductive material comprises one or more of a metal, an electrically conductive polymer and an electrically conductive ceramic.
  • Suitable electrically conductive metals include, but are not limited to, aluminium, silver, nickel, gold, platinum, copper, tungsten, and alloys thereof.
  • the electrically conductive material comprises a metal powder suspended in a glue, such as an epoxy resin.
  • the electrically conductive material comprises silver-loaded epoxy.
  • Suitable electrically conductive polymers include PEDOT (poly(3,4- ethylenedioxythiophene)), PSS (poly(p-phenylene sulfide)), PEDOT:PSS (mixture of both PEDOT and PSS), PANI (polyanilines), PPY (poly(pyrrole)s), PPV (Poly(p-phenylene vinylene)), or any combination thereof.
  • Suitable electrically conductive ceramics include ITO (Indium Tin Oxide), SLT (lanthanum-doped strontium titanate), SYT (yttrium-doped strontium titanate), or any combination thereof.
  • the electrically conductive material may further comprise one or more additives selected from a group consisting of: solvents; curing agents; adhesion promoters; surfactants; viscosity reduction agents; and aggregation inhibitors.
  • additives may be used, for example, to aid deposition of the electrically conductive material on the porous outer surface of the porous body, to increase the amount by which the electrically conductive material diffuses into the porous outer surface of the porous body, to reduce the time required for the electrically conductive material to set, to increase the level of adhesion between the electrically conductive material and the porous body, or to reduce the amount of aggregation of suspended particles, such as metal particles or powder, in the electrically conductive material prior to application onto the porous outer surface of the porous body.
  • the heating element may have any length.
  • the “length” of the heating element may refer to the extension of the heating element measured along the longitudinal axis, between the liquid absorption surface and the heating surface of the porous body of the heater assembly. Since the length of the heating element may be considerably smaller than the “width” of the heater assembly, the “length” of the heating element, and similar components, may also be referred to as the “thickness” of the heating element.
  • the heating element may have a thickness of at least 1 micrometre.
  • the heating element may have a thickness of at least 2 micrometres.
  • the heating element may have a thickness of at least 5 micrometres.
  • the heating element may have a thickness of at least 200 micrometres.
  • the heating element may have a thickness of at least 220 micrometres.
  • the heating element may have a thickness of less than 300 micrometres.
  • the heating element may have a thickness of less than 250 micrometres.
  • the heating element may have a thickness of less than 50 micrometres.
  • the heating element may have a thickness of less than 20 micrometres.
  • the heating element may have a thickness of between 1 millimetre and 10 millimetres.
  • the heating element may have a thickness of between 1 millimetre and 5 millimetres.
  • the heating element may have a thickness of between 2 millimetres and 5 millimetres.
  • the heating element may have a thickness of between 200 micrometres and 300 micrometres.
  • the heating element may have a thickness of between 200 micrometres and 250 micrometres.
  • the heating element may have a thickness of between 220 micrometres and 300 micrometres.
  • the heater assembly may further comprise first and second electrical contacts connected to the heating element. Each electrical contact may be disposed at opposite sides of the heating surface of the porous body. The heating element may extend between the electrical contacts. The electrical heating element may form an electrical connection therebetween.
  • the electrical contacts may be formed from any suitable material. Examples of suitable materials for the electrical contacts include but are not limited to copper, zinc, silver, and gold.
  • the first and second electrical contacts may be formed from an electrically conductive material deposited directly onto the heating surface of the porous body.
  • the electrical heating element may extend between the electrical contacts in a wavelike or serpentine manner. This helps to increase the length of the heating element between the electrical contacts that is in contact with the porous outer surface, which helps to improve heating of the liquid aerosol-forming substrate.
  • the porous body may comprise any material.
  • the porous body may comprise any porous material.
  • the porous body may comprise a heat resistant material.
  • the porous body may comprise at least one of an oxide ceramic material, a non-oxide ceramic material, a glass-ceramic material, a semiconductor material, a glass material, and a polymeric material.
  • the porous body may comprise at least one of alumina, aluminosilicate, zirconia, silicon carbide, silicon nitride, a lithium-aluminosilicate glass-ceramic, a silicide material, and a boride material.
  • the porous body may comprise an inert ceramic or bio-compatible ceramic.
  • suitable ceramics are ceramics comprising aluminium oxides, zirconium oxides, silicon oxides, calcium silicates and calcium phosphate including hydroxyapatite.
  • the porous body may comprise a ceramic comprising one or more of AI2O3, ZrC>2, SiC>2 and Ca 2 SiC>3.
  • the porous body comprises a ceramic comprising one or both of SiC>2 and Ca2SiC>3.
  • the porous body may comprise a capillary material that conveys a liquid aerosolforming substrate through the material by capillary action.
  • the porous body may have a fibrous or porous structure.
  • the porous body may comprise a bundle of capillaries.
  • the porous body may comprise a plurality of fibres or threads or other fine bore tubes.
  • the porous body may comprise fibres or threads of cotton or treated cotton, for example, acetylated cotton.
  • Other suitable materials could also be used, for example, ceramic- or graphite based fibrous materials or materials made from spun, drawn or extruded fibres, such as fiberglass, cellulose acetate or any suitable heat resistant polymer.
  • the porous body may comprise a plurality of interconnected open cell pores.
  • the porous body may comprise a capillary material that conveys a liquid through the material by capillary action.
  • the porous body may have a fibrous or porous structure.
  • the porous body may comprise a bundle of capillaries.
  • the porous body may comprise a plurality of fibres or threads or other fine bore tubes.
  • the porous body may comprise fibres or threads of cotton or treated cotton, for example, acetylated cotton.
  • Other suitable materials could also be used, for example, ceramic- or graphite based fibrous materials or materials made from spun, drawn or extruded fibres, such as fiberglass, cellulose acetate or any suitable heat resistant polymer.
  • the specific pore sizes in the porous body of the present invention may be made using any suitable method.
  • the pores in the porous body may be manufactured using etching techniques into a monolithic portion of material.
  • the pore sizes may be manufactured using a controlled sintering process, a sol-gel process, or a phase separation process. These processes enable that the porous body is provided with pores, which in turn enables the liquid aerosol-forming substrate to be conveyed from the liquid absorption surface to the heating surface.
  • the porous body may be substantially incompressible.
  • the porous body may be incompressible.
  • the pores of the porous body may have any shape.
  • the pores of the porous body may be interconnected pores.
  • the porous body may comprise a plurality of longitudinal pores extending from the liquid absorption surface of the porous body to the heating surface of the porous body.
  • the pore size may be the width of the longitudinal pores when measured in the transverse direction.
  • transverse refers to a direction which is orthogonal to the longitudinal axis.
  • the provision of longitudinally extending pores may advantageously facilitate efficient transfer of liquid aerosol-forming substrate from the liquid absorption surface of the porous body to the heating surface of the porous body.
  • the porous body may comprise a longitudinal surface extending between the liquid absorption surface and the heating surface.
  • the longitudinal surface may be liquid impermeable.
  • the provision of a liquid impermeable longitudinal surface may advantageously prevent the liquid aerosol-forming substrate from leaking out of the longitudinal surface of the porous body.
  • the porous body may comprise a liquid impermeable coating provided on the longitudinal surface of the porous body.
  • the porous body may comprise longitudinally extending pores preventing liquid aerosol-forming substrate from reaching the longitudinal surface of the porous body.
  • the pore size of the porous body at the longitudinal surface may be sufficiently small so as to prevent liquid aerosol-forming substrate from reaching the longitudinal surface of the porous body.
  • the porous body may be inserted into a liquid impermeable housing, such as a glass tube, to prevent liquid aerosolforming substrate from leaking.
  • the porous body may comprise a longitudinal groove extending along the longitudinal surface of the porous body between the liquid absorption surface and the heating surface.
  • the longitudinal groove may extend all the way from the liquid absorption surface of the porous body to the heating surface of the porous body.
  • the provision of a longitudinal groove may allow air to pass from the liquid absorption surface of the porous body to the heating surface of the porous body.
  • the longitudinal grooves may advantageously direct and channel air towards the heating surface of the porous body when a user draws on the aerosol-generating system. When the air passes the heating surface, it may become entrained with aerosol generated by the heating element before being delivered to a user.
  • the porous body may comprise more than one longitudinal groove.
  • the porous body may comprise at least 2, at least 3, at least 4, or at least 5 longitudinal grooves.
  • the longitudinal grooves may be evenly distributed around the periphery of the porous body.
  • the porous body may have a substantially constant cross section.
  • the cross sectional area of the liquid absorption surface of the porous body may be substantially the same as the cross sectional area of the heating surface.
  • the porous body may have any shape.
  • the porous body may be generally cylindrical. Where this is the case, both the liquid absorption surface and the heating surface may be circular.
  • the porous body may have the shape of a regular cuboid. Where this is the case, both the liquid absorption surface and the heating surface may be square.
  • the liquid absorption surface of the porous body may have an area that is different to an area of the heating surface of the porous body.
  • the area of the heating surface of the porous body may be less than the area of the liquid absorption surface of the porous body.
  • a ratio of the area of the heating surface of the porous body to the area of the liquid absorption surface of the porous body may be less than or equal to 0.9.
  • a ratio of the area of the heating surface of the porous body to the area of the liquid absorption surface of the porous body may be at least 0.1.
  • a ratio of the area of the heating surface of the porous body to the area of the liquid absorption surface of the porous body may be between 0.1 and 0.9.
  • the area of the liquid absorption surface of the porous body may be less than the area of the heating surface of the porous body.
  • a ratio of the area of the liquid absorption surface of the porous body to the area of the heating surface of the porous body may be less than or equal to 0.9.
  • a ratio of the area of the liquid absorption surface of the porous body to the area of the heating surface of the porous body may be at least 0.1.
  • a ratio of the area of the liquid absorption surface of the porous body to the area of the heating surface of the porous body may be between 0.1 and 0.9.
  • a heater assembly having a heating surface with the same area as the liquid absorption surface may be inefficient due to heat generated by the heater not being used to vaporise an aerosol-forming substrate.
  • An inefficient heater assembly provides a reduced throughput of aerosol.
  • providing a porous body in which the heating surface and the liquid absorption surface have different areas may improve the throughput of aerosol that can be generated by the heater assembly compared to a heater assembly in which the heating surface has the same area as the liquid absorption surface.
  • heat flow from the heating element towards the liquid absorption surface and then to the liquid storage portion by conduction may be reduced.
  • the relatively smaller heating surface provides a small heat transfer area through which the transfer heat, by conduction, from the heating element to the porous body, and towards the liquid absorption surface.
  • the smaller area of the liquid absorption surface may cause a reduction in heat flow through the aerosol- forming substrate from the heating element to the liquid absorption surface via heat conduction.
  • Reducing heat flow from the heating surface to the liquid absorption surface may consequently increase heating efficiency because more of the heat energy provided by the heating element may be used to vaporise the liquid aerosol-forming substrate. Consequently, the porous body having a shape such that the liquid absorption surface has a smaller area than the heating surface may provide for increased heating efficiency, which may increase the throughput of aerosol generated by the heater assembly.
  • Increasing heating efficiency may reduce power consumption during use of the heater assembly.
  • the area of the heating surface of the porous body may be less than the area of the liquid absorption surface of the porous body.
  • the area of the liquid absorption surface of the porous body may be greater than the area of the heating surface of the porous body.
  • the porous body has a shape such that the heating surface has a smaller area than the liquid absorption surface
  • heat flow from the heating element towards the liquid absorption surface and then to the liquid storage portion by conduction may be reduced.
  • the relatively smaller heating surface provides a small heat transfer area through which the transfer heat, by conduction, from the heating element to the porous body, and towards the liquid absorption surface.
  • the porous body having a shape such that the heating surface has a smaller area than the liquid absorption surface may reduce the area of the heating surface that is not close enough to the heating element to allow aerosol-forming substrate being conveyed to the heating surface to be vaporised.
  • the size and shape of the heating surface may more closely match with the size and shape of the heating element. Consequently, more of the liquid aerosol-forming substrate may be conveyed from the liquid absorption surface to an area of the heating surface that is near to the heating element, which may result in more of the liquid aerosol-forming substrate at the heating surface being vaporised. More liquid aerosol-forming substrate being vaporised may increase the throughput of aerosol generated by the heater assembly.
  • this arrangement may allow for the power density at the heating surface to be maximised, which also improves heating efficiency.
  • the liquid absorption surface having a larger area than the heating surface may allow the liquid absorption surface to receive a larger volume of liquid aerosolsubstrate from a liquid storage portion.
  • the flow rate of the liquid aerosol-forming substrate to the heating element may be higher than with a typical heater assembly.
  • a higher flow rate of liquid aerosol-forming substrate at the heating element may increase the throughput of aerosol generated by the heater assembly.
  • the area of the heating surface of the porous body may be greater than the area of the liquid absorption surface of the porous body.
  • the area of the liquid absorption surface of the porous body may be less than the area of the heating surface of the porous body.
  • the porous body when the porous body has a shape such that the liquid absorption surface has a smaller area than the heating surface, the smaller area of the liquid absorption surface may cause a reduction in heat flow through the aerosol-forming substrate from the heating element to the liquid absorption surface via heat conduction. Reducing heat flow from the heating surface to the liquid absorption surface may consequently increase thermal efficiency because more of the heat energy provided by the heating element may be used to vaporise the liquid aerosol-forming substrate. Consequently, the porous body having a shape such that the liquid absorption surface has a smaller area than the heating surface may provide for increased heating efficiency, which may increase the throughput of aerosol generated by the heater assembly.
  • the porous body having a shape such that the liquid absorption surface has a smaller area than the heating surface may reduce the area of the heating surface that is not close enough to the heating element to allow aerosol-forming substrate being conveyed to the heating surface to be vaporised.
  • the size and shape of the heating surface may more closely match with the size and shape of the heating element. Consequently, more of the liquid aerosol-forming substrate being may be conveyed from the liquid absorption surface and to an area of the heating surface that is near to the heating element, which may result in more of the liquid aerosol-forming substrate at the heating surface being vaporised. More liquid aerosol-forming substrate being vaporised may increase the throughput of aerosol generated by the heater assembly.
  • the porous body may have any cross sectional shape.
  • the porous body may have a rectangular or a circular cross sectional shape.
  • the heating surface of the porous body may have any shape.
  • the heating surface of the porous body may be curved along one or both of a first transverse direction and a second transverse direction, the first transverse direction being orthogonal to the second transverse direction.
  • the heating surface of the porous ceramic body may be convex in one or both of a first transverse direction and a second transverse direction, the first transverse direction being orthogonal to the second transverse direction.
  • porous ceramic body may enable the surface area of the heating surface to be increased without increasing a width of the heating surface. This may increase the efficiency of the aerosol-generating system at vaporising liquid aerosol-forming substrate, whilst helping to avoid the need to redesign other components of the aerosol-generating system to accommodate the porous ceramic body.
  • a heating surface that is convex along one or both of a first transverse direction and a second transverse direction may help to avoid or minimise recirculation of airflow adjacent the heater assembly.
  • a heating surface that is convex may help to avoid or minimise recirculation of airflow adjacent to a central region of the heater assembly. This may reduce a level of turbulence in the airflow adjacent to the heater assembly. Reducing a level of turbulence in the airflow adjacent to the heater assembly may improve the entrainment of vapour of aerosol-forming substrate in the airflow. This may improve the quality of the aerosol generated by the aerosol-generating system.
  • Improving the entrainment of vapour in the airflow through the aerosol-generating system may avoid or reduce vapour condensing to form large droplets of liquid aerosol-forming substrate. This may help to avoid an unpleasant and undesirable user experience.
  • Improving the entrainment of vapour in the airflow through the aerosol-generating system may avoid or reduce vapour condensing on internal surfaces of the aerosol-generating system. This may help to avoid or minimise damage to the aerosol-generating system and may allow optimal function of the aerosol-generating system.
  • the heating surface of the porous body may be convex in a single transverse direction.
  • the heating surface of the porous body may be convex in both the first transverse direction and the second transverse direction.
  • the heating surface of the porous body may be convex in one or both of the first transverse direction and the second transverse direction based on the configuration of the heater assembly relative to one or more airflow pathways of the aerosol-generating system.
  • the heater assembly may be configured to minimise a level of turbulence in the airflow adjacent to the heater assembly.
  • the heating element may be convex in one or both of the first transverse direction and the second transverse direction.
  • the curvature of the heating element in the first transverse direction may be substantially the same as the curvature of the heating surface of the porous body in the first transverse direction.
  • the curvature of the heating element in the second transverse direction may be substantially the same as the curvature of the heating surface of the porous body in the second transverse direction.
  • the curvature of the heating element in both the first transverse direction and the second transverse direction may be substantially the same as the curvature of the heating surface of the porous body in both the first transverse direction and the second transverse direction, respectively.
  • the heater assembly may further comprise a thermally insulating layer having a lower thermal conductivity than the porous body, wherein the thermally insulating layer is disposed between and is in contact with each of the porous body and the heating element, and the thermally insulating layer is configured to reduce heat transfer from the heating element to the porous body.
  • the heat losses from the heating element to the porous ceramic body, and to liquid within the porous ceramic body are reduced.
  • This provides a more efficient heater assembly in which the amount of use and number of uses of the device by a user can be increased, before the device power supply, such as a battery, is depleted.
  • the inventors have estimated that in a known device, approximately one third of energy from the heating element is lost through conduction in the porous body and liquid in the porous body. The remaining two thirds are used to generate an aerosol by heating a liquid aerosol-forming substrate. In the arrangement described herein, these energy losses are reduced.
  • the thermally insulting layer reduces heat propagation or conduction from the heating element towards or through the porous ceramic body.
  • the thermally insulating layer may comprise a thermally insulating material.
  • the thermally insulating material may have a lower thermal conductivity than the porous ceramic body.
  • the thermally insulating material may have a higher porosity than the porous ceramic body. This has the advantage of providing a thermally insulating layer which is particularly effective at reducing energy losses, while being easy to manufacture.
  • the thermally insulating layer may comprise a material having a thermal conductivity of less than 40 Watts per metre-Kelvin. This has the advantage of providing a thermally insulating layer which is effective at reducing energy losses through the porous ceramic body.
  • the thermally insulating layer may comprise a material having a thermal conductivity of less than 10 Watts per metre-Kelvin. This has the advantage of providing a thermally insulating layer which is particularly effective at reducing energy losses through the porous ceramic body.
  • the thermally insulating layer may extend entirely between the porous ceramic body and the heating element. This has the advantage of more effectively providing a barrier between the heating element and the porous ceramic body, and as such is particularly effective at reducing energy losses through the porous ceramic body.
  • the thermally insulating layer may comprise one or more of: alumina, zirconia, zirconia with magnesium oxide, glass ceramic, quartz, a porous polymer.
  • the porous polymer may be polyimide.
  • the thermally insulating layer may comprise alumina having a thermal conductivity of 20 - 40 Watts per metre-Kelvin.
  • the thermally insulating layer may comprise a material having a thermal conductivity of less than 10 Watts per metre-Kelvin, such as zirconia with or without magnesium oxide, glass ceramics, quartz.
  • zirconia with or without magnesium oxide, glass ceramics, quartz is advantageous, as these materials are compatible with a manufacturing process involving sintering, and as such a heater assembly having a thermally insulating layer of one of these materials is more easily manufactured.
  • the thermally insulating layer may have a thickness of between 0.1 millimetres and 2 millimetres.
  • a thermally insulating layer with such a thickness is particularly suited to reducing energy losses from the heating element to the porous ceramic body.
  • the thermally insulating layer has a thickness of between 0.5 millimetres and 1.5 millimetres.
  • a thermally insulating layer with such a thickness is further suited to reducing energy losses from the heating element to the porous ceramic body.
  • thermally insulating refers to a property in which heat transfer is reduced or restricted. A more thermally insulating component will transfer less heat, via conduction, convection or radiation, than a more thermally insulating component.
  • the heating element may comprise a plurality of tracks or track portions arranged electrically in parallel.
  • the heating element resistance at room temperature may be between 0.5 Ohms and 1.5 Ohms, preferably between 0.7 Ohms and 1.3 Ohms, and more preferably 1 Ohm.
  • the resistance of the heating element may be matched to requirements of control electronics.
  • At least two of the electrically parallel heating tracks may have similar resistances to each other, or have the same resistance as each other.
  • all of the electrically parallel heating tracks are of similar or of the same resistance as each other.
  • the heating tracks arranged electrically in parallel may have different resistances, which is particularly beneficial in a heater assembly where it is advantageous for zones of the heating element to generate different power levels. This could be the case, for example, to compensate for higher thermal losses in an outer part of the heating element.
  • heating tracks on an exterior or outer part of the heating element may be designed to have a lower resistance (which can generate more heat) than heating tracks in the centre of the heating element.
  • the heating element may comprise a plurality of tracks or track portions.
  • the plurality of tracks or track portions may be arranged electrically in parallel. By being arranged electrically in parallel, current flow is split into separate parallel flow paths, the separate parallel flow paths being subsequently re-combined.
  • the heating element may comprise a first connecting pad and a second connecting pad.
  • the first or second connecting pads (or first and second connecting pads) may be configured to allow connection to an external circuit.
  • An aperture or plurality of apertures in the heating element may separate each track or track portion.
  • the heating element may comprise at least one diverging portion, in which current is split from the first connecting pad into track portions.
  • the track portions define electrically parallel paths.
  • the heating element may comprise a converging portion. In the converging portion, current is combined from track portions which define electrically parallel paths, into the second connecting pad.
  • the heating element may comprise two, three, four or more track portions which define electrically parallel paths.
  • the inventors have also identified that the electrically parallel tracks or track portions have a surprising additional advantage.
  • the heating element in case of breakage of one track portion, the heating element will still operate and can, for an initial transitory period, operate in an advantageous way because the breakage of one track or track portion would result in a higher energy density on the remaining tracks or track portions.
  • the same power would still be provided but over a smaller area, so throughput of the aerosolgenerating substrate is increased.
  • Such a breakage causing an increase in current on unbroken tracks or track portions can eventually affect the user’s experience. This can be mitigated for by a mechanism to alert the user about possible future below optimal performance of the heater assembly.
  • the heating element may comprise a plurality of tracks or track portions defining a path having at least one bend, the inner edge of the bend being curved.
  • the inner edge of the bend being curved has the advantage of guiding current to flow in a more evenly distributed way around the at least one bend. This reduces a current concentration which in turn limits hot spot creation.
  • the heating element may comprise a plurality of tracks or track portions having a gradient of electrical resistivity perpendicular to current flow in a corner or corners, such that the electrical resistivity is higher at an inner part of the corner and lower at an outer part of the corner.
  • a gradient is beneficial to counterbalance localized high current density and reduce hot spot creation.
  • the heating element may comprise a plurality of tracks or track portions arranged with a distance between at least two of the plurality of tracks or track portions in the range 150 to 300 micrometres.
  • All of the tracks or track portions may be spaced apart from at least one other track portion by 200 to 300 micrometres. This has the advantage of providing a particularly efficient heater assembly, in which an aerosol-forming substrate is efficiently vaporised.
  • the heating element and the porous body may be moulded as a single monolithic piece.
  • This may also help to simplify the manufacturing of the heater assembly by reducing manufacturing times and providing a more cost effective solution. This may advantageously create a tight mechanical connection between the heating element and the porous body.
  • the heating element may be a doped portion of the porous body.
  • the porous body may be doped such that the portion of the porous body which acts as the heating element is electrically conductive. Doping the porous body may be advantageous in that it avoids altering the porosity of the porous body. This may be preferable to other known techniques of forming a heating element, which involve depositing the heating element by thin film or thick film techniques, which can reduce the properties of the porous body, in particular the porosity.
  • the doped portion may be between 5 micrometres and 100 micrometres in thickness. The thickness of the doped portion may be increased where the cross sectional area of the heating element is smaller or where the heating resistance required is higher.
  • the dopant used to dope the porous body may be an n-type dopant or a p-type dopant. The dopant may be any one of, but not limited to, nitrogen, phosphorous, aluminium or boron.
  • the interface between the heating element and the porous body may comprise a portion of partially doped porous material.
  • the porous body may be doped by ion implantation.
  • Ion implantation involves the implantation of ions into a layer of bulk material or the exchange of ions, taking one species out and replacing it by another. Ion implantation can be carried out chemically or physically.
  • the porous body may be doped by transmutation. Transmutation changes one species of atom already present in the material into another by irradiation with particles, such as neutrons or alpha particles, which leads to a short lived decay process leading to a stable isotope which was not present in the original material. Transmutation is advantageous in that the doping occurs directly in the ceramic material and does not require the bonding or attachment of an additional electrically conductive material. Transmutation therefore provides a more monolithic approach
  • a cartridge for an aerosol-generating system comprising a heater assembly according to the present invention.
  • the cartridge further comprises a liquid storage portion configured to hold a liquid aerosol-forming substrate. Liquid storage portion is arranged at the liquid absorption surface of the porous body.
  • the liquid storage portion may also be known as a reservoir.
  • the liquid storage portion may contain a liquid aerosol-forming substrate.
  • the liquid aerosol-forming substrate he aerosol- forming substrate may comprise both liquid and solid components.
  • the liquid aerosol-forming substrate may comprise nicotine.
  • the nicotine containing liquid aerosol-forming substrate may be a nicotine salt matrix.
  • the liquid aerosol-forming substrate may comprise plant-based material.
  • the liquid aerosolforming substrate may comprise tobacco.
  • the liquid aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds, which are released from the aerosol-forming substrate upon heating.
  • the liquid aerosol-forming substrate may comprise homogenised tobacco material.
  • the liquid aerosol-forming substrate may comprise a non-tobacco-containing material.
  • the liquid aerosol-forming substrate may comprise homogenised plant-based material.
  • the liquid aerosol-forming substrate may comprise one or more aerosol-formers.
  • An aerosol-former is any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol and that is substantially resistant to thermal degradation at the temperature of operation of the system.
  • suitable aerosol formers include glycerine and propylene glycol.
  • Suitable aerosol-formers are well known in the art and include, but are not limited to: polyhydric alcohols, such as triethylene glycol, 1 ,3- butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.
  • the liquid aerosol-forming substrate may comprise water, solvents, ethanol, plant extracts and natural or artificial flavours.
  • the liquid aerosol-forming substrate may comprise nicotine and at least one aerosolformer.
  • the aerosol-former may be glycerine or propylene glycol.
  • the aerosol former may comprise both glycerine and propylene glycol.
  • the liquid aerosol-forming substrate may have a nicotine concentration of between about 0.5% and about 10%, for example about 2%.
  • the liquid storage portion may be disposed at the liquid absorption surface of the porous body.
  • An airflow channel may be disposed at the heating surface of the porous body.
  • the airflow channel may be adjacent to the heating element.
  • An airflow path may extend past the heating element.
  • the airflow path may be configured to convey the aerosol.
  • the cartridge body may be configured such that air flow past the heater assembly entrains vapourised aerosol-forming substrate.
  • the cartridge may have a mouthpiece arranged at a mouth end of the cartridge.
  • the mouth piece may have an aerosol outlet through which generated aerosol may be drawn by a user.
  • the cartridge may have a connection end configured to couple the cartridge to an aerosol-generating device.
  • the cartridge may comprise an air inlet.
  • the cartridge may comprise an enclosed airflow passage from the air inlet to the aerosol outlet.
  • the enclosed airflow passage may extend from the air inlet, past the heater assembly, to the aerosol outlet.
  • the enclosed airflow passage may pass around an external surface of the liquid storage portion.
  • the enclosed airflow passage may pass through the liquid storage portion.
  • the liquid storage portion may have an annular cross-section defining an internal passage, and the airflow passage may extend through the internal passage of the liquid storage portion.
  • the cartridge may comprise a first airflow pathway that extends from the air inlet towards the heater assembly in a first direction.
  • the cartridge may comprise a second airflow pathway that extends past the heating element and is configured to entrain the aerosol.
  • the cartridge may comprise a third airflow pathway that extends from the heater assembly to an aerosol outlet in a second direction.
  • the second direction may be opposite to the first direction.
  • the second airflow pathway may provide a fluid connection between the first airflow pathway and the third airflow pathway.
  • the cartridge may comprise a cartridge housing.
  • the cartridge housing may be formed from a durable material.
  • the cartridge housing may be formed from a liquid impermeable material.
  • the cartridge housing may be formed form a mouldable plastics material, such as polypropylene (PP) or polyethylene terephthalate (PET) or a copolymer such as TritanTM, which is made from three monomers: dimethyl terephthalate (DMT), cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1 ,3-cyclobutanediol (CBDO).
  • the cartridge housing of the cartridge may define a portion of the liquid storage portion or reservoir.
  • the cartridge housing may define the liquid storage portion.
  • the cartridge housing and the liquid storage portion may be integrally formed. Alternatively, the liquid storage portion may be formed separately from the outer housing and arranged in the outer housing.
  • an aerosolgenerating system comprising a cartridge according to the present invention.
  • the system may further comprise an aerosol-generating device comprising a power supply for supplying power to the heater assembly and control circuitry for controlling the supply of power from the power supply to the heater assembly.
  • the cartridge is removably couplable to the aerosol-generating device.
  • the aerosol-generating system may further comprise an air inlet and an aerosol outlet, the air inlet being in fluid communication with the aerosol outlet to define an airflow pathway through the aerosol-generating system.
  • the heater assembly may be arranged in fluid communication with the airflow pathway such that airflows past the heater assembly in an average airflow direction, wherein the heater assembly and airflow pathway are arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 135 degrees.
  • an aerosolgenerating system comprising: a heater assembly according to the present invention, an air inlet and an aerosol outlet, the air inlet being in fluid communication with the aerosol outlet to define an airflow pathway through the aerosol-generating system; wherein the heater assembly is arranged in fluid communication with the airflow pathway such that air flows past the heater assembly in an average airflow direction, wherein the heater assembly and airflow pathway are arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 135 degrees.
  • the aerosol-generating system may comprise: a heater assembly comprising: a heating element for vaporising a liquid aerosol-forming substrate, and a porous body for conveying the liquid aerosol-forming substrate to the heating element, the porous body having a liquid absorption surface and a heating surface, the heating element being located on the heating surface of the porous body, the heating element and the porous body being integrally formed, wherein the average pore size of the porous body varies between the liquid absorption surface and the heating surface; wherein the aerosol-generating system further comprises an air inlet and an aerosol outlet, the air inlet being in fluid communication with the aerosol outlet to define an airflow pathway through the aerosol-generating system; wherein the heater assembly is arranged in fluid communication with the airflow pathway such that air flows past the heater assembly in an average airflow direction, wherein the heater assembly and airflow pathway are arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 135 degrees.
  • an angle between the average vapour emission direction and the average airflow direction refers to an angle between the directions of travel of the vapour being emitted from the heater assembly and the airflow within the airflow pathway. For example, an angle of zero degrees would mean that the airflow and vapour emissions are travelling in the same direction, whereas an angle of 180 degrees would mean that the directions of travel of the airflow and vapour emission directly oppose one another.
  • the average airflow direction does not directly oppose the average vapour emission direction. Therefore, the momentum of the vapour and the airflow is not reduced to the same extent as when the average airflow direction does directly oppose the average vapour emission direction. This reduces the tendency for recirculation and turbulence to occur in the airflow path and the vapour is less likely to impinge on the internal surfaces of the aerosol-generating system. Accordingly, condensation of aerosol within the aerosolgenerating system is less likely to occur.
  • the average vapour emission direction may be substantially perpendicular to the heating surface.
  • substantially perpendicular means 90 degrees plus or minus 10 degrees, preferably plus or minus 5 degrees.
  • An advantage of the average vapour emission direction being substantially perpendicular to the heating surface is that it makes orientating the average vapour emission direction relative to the average airflow direction straightforward because the vapour will be emitted substantially perpendicular to the heating surface of the porous body. Therefore, by angling the heater assembly appropriately relative to the airflow in the airflow pathway or vice versa, a desired angle between the average vapour emission direction and average airflow direction can be achieved.
  • the heater assembly and airflow pathway may be arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 110 degrees, preferably less than 100 degrees.
  • the heater assembly and airflow pathway may be arranged such that an angle between the average vapour emission direction and the average airflow direction is approximately 90 degrees. This arrangement results in the vapour being emitted at an angle substantially perpendicular to the average airflow direction.
  • the average vapour emission direction has no speed or direction component that opposes the airflow direction and therefore any loss of momentum of the airflow is reduced. This reduces the tendency for recirculation and turbulence to occur in the airflow path and the vapour is less likely to impinge on the internal surfaces of the aerosol-generating system. Furthermore, entrainment of the vapour in the airflow is improved. Accordingly, condensation of aerosol within the aerosol-generating system is less likely to occur.
  • the heater assembly and airflow pathway may be arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 90 degrees.
  • the average vapour emission direction has no speed or direction component that opposes the airflow direction and actually has a speed and direction component in the same direction as the average airflow direction. Therefore, any loss of momentum of the airflow is further reduced. This reduces the tendency for recirculation and turbulence to occur in the airflow path and the vapour is less likely to impinge on the internal surfaces of the aerosol-generating system. Furthermore, entrainment of the vapour in the airflow is improved. Accordingly, condensation of aerosol within the aerosol-generating system is less likely to occur.
  • the heater assembly and airflow pathway may be arranged such that an angle between the average vapour emission direction and the average airflow direction is approximately 45 degrees.
  • the heater assembly and airflow pathway may be arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 45 degrees.
  • the heater assembly and airflow pathway may be arranged such that the average vapour emission direction and the average airflow direction are substantially the same.
  • a cross-sectional area of the airflow pathway in the region of the heater assembly may be configured such that, in use, the airflow speed is between 0.1 and 2 metres per second, preferably between 0.5 and 1.5 metres per second and more preferably approximately 1 metre per second. This range of airflow speeds has been found to effectively entrain the vapour emitted from different designs of heating element without excessively cooling the heating element.
  • the aerosol-generating device may comprise a housing.
  • the housing may be elongate.
  • the housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK) and polyethylene.
  • PEEK polyetheretherketone
  • the material is preferably light and non-brittle.
  • the aerosol-generating device housing may define a cavity or recess for receiving a portion of a cartridge.
  • the aerosol-generating device may have a connection end configured to removeably connect the aerosol-generating device to a cartridge.
  • the connection end may comprise the cavity or recess for receiving the cartridge.
  • the aerosol-generating device may have a distal end, opposite the connection end.
  • the distal end may comprise an electrical connector configured to connect the aerosolgenerating device to an electrical connector of an external power supply, for charging the power supply of the aerosol-generating device.
  • the aerosol-generating system may comprise an air inlet.
  • the air inlet may be arranged at an interface between the cartridge and the aerosol-generating device.
  • the aerosol-generating system may comprise an enclosed airflow passage from the air inlet to an aerosol outlet in a mouthpiece.
  • the enclosed airflow passage may extend from the air inlet, past the heater assembly, to the aerosol outlet.
  • the aerosol-generating system may comprise a first airflow pathway that extends from the air inlet towards the heater assembly in a first direction.
  • the aerosol-generating system may comprise a second airflow pathway that extends past the electrical heating element and is configured to entrain the aerosol.
  • the aerosol-generating system may comprise a third airflow pathway that extends from the heater assembly to an aerosol outlet in a second direction. The second direction may be opposite to the first direction.
  • the second airflow pathway may provide a fluid connection between the first airflow pathway and the third airflow pathway.
  • the power supply may be any suitable power supply.
  • the power supply is a DC power supply.
  • the power supply may be a battery.
  • the battery may be a Lithium based battery, for example a Lithium-Cobalt, a Lithium-lron-Phosphate, a Lithium Titanate or a Lithium-Polymer battery.
  • the battery may be a Nickel-metal hydride battery or a Nickel cadmium battery.
  • the power supply may be another form of charge storage device such as a capacitor.
  • the power supply may be rechargeable and be configured for many cycles of charge and discharge.
  • the power supply may have a capacity that allows for the storage of enough energy for one or more user experiences of the aerosol-generating system; for example, the power supply may have sufficient capacity to allow for the continuous generation of aerosol for a period of around six minutes, corresponding to the typical time taken to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to allow for a predetermined number of puffs or discrete activations of the aerosol-generating system.
  • the control circuitry may comprise any suitable controller or electrical components.
  • the controller may comprise a memory. Information for performing the above-described method may be stored in the memory.
  • the control circuitry may comprise a microprocessor.
  • the microprocessor may be a programmable microprocessor, a microcontroller, or an application specific integrated chip (ASIC) or other electronic circuitry capable of providing control.
  • the control circuitry may be configured to supply power to the heating element continuously following activation of the device, or may be configured to supply power intermittently, such as on a puff-by-puff basis.
  • the power may be supplied to the heating element in the form of pulses of electrical current, for example, by means of pulse width modulation (PWM).
  • PWM pulse width modulation
  • control circuitry may comprise further electronic components.
  • control circuitry may comprise any of: sensors, switches, display elements.
  • the aerosol-generating system may comprise a puff detector.
  • the puff detector may be configured to detect when a user draws on the aerosol-generating system.
  • the puff detector may be any suitable sensor that is capable of detecting when a user draws on the aerosol-generating device.
  • the puff detector may be an airflow sensor.
  • the control circuitry may be configured to supply power to the heating element when the puff detector detects a user drawing on the aerosol-generating system.
  • Example Ex1 A heater assembly for an aerosol-generating system, the heater assembly comprising a heating element for vaporising a liquid aerosol-forming substrate, and a porous body for conveying the liquid aerosol-forming substrate to the heating element, the porous body having a liquid absorption surface and a heating surface, the heating element being located on the heating surface of the porous body, the heating element and the porous body being integrally formed, wherein the average pore size of the porous body varies between the liquid absorption surface and the heating surface.
  • Example Ex 2 A heater assembly according to Ex1 , wherein the porous body has a heating end and a liquid absorption end, the heating surface being disposed at the heating end, and the liquid absorption surface being disposed at the liquid absorption end, wherein the porous body has a first average pore size at the liquid absorption end, and a second average pore size at the heating end, first average pore size being greater than the second average pore size.
  • Example Ex 3 A heater assembly according to Ex2, wherein the first average pore size is between 5 micrometres and 200 micrometres.
  • Example Ex 4. A heater assembly according to Ex2 or Ex3, wherein the porous body comprises a first porous material at the liquid absorption end, and a second porous material at the heating end, the first porous material having the first average pore size, and the second porous material having the second average pore size.
  • Example Ex 5 A heater assembly according to Ex4, wherein the length of the first porous material is greater than the length of the second porous material.
  • Example Ex 6 A heater assembly according to Ex5, wherein the ratio of the length of the first porous material to the length of the second porous material is at least 2.
  • Example Ex 7 A heater assembly according to any preceding Example, wherein the area of the heating surface of the porous body is substantially the same as the area of the heating element.
  • Example Ex 8 A heater assembly according to any preceding Example, wherein the heating element is fluid permeable.
  • Example Ex 9 A heater assembly according to any preceding Example, wherein the porous body comprises at least one of an oxide ceramic material, a non-oxide ceramic material, a glass-ceramic material, a semiconductor material, a glass material, and a polymeric material.
  • Example Ex 10 A heater assembly according to any preceding Example, wherein the porous body comprises at least one of alumina, aluminosilicate, zirconia, silicon carbide, silicon nitride, a lithium-aluminosilicate glass-ceramic, a silicide material, and a boride material.
  • the porous body comprises at least one of alumina, aluminosilicate, zirconia, silicon carbide, silicon nitride, a lithium-aluminosilicate glass-ceramic, a silicide material, and a boride material.
  • Example Ex 11 A heater assembly according to any preceding Example, wherein the porous body comprises a plurality of longitudinal pores extending from the liquid absorption surface of the porous body to the heating surface of the porous body.
  • Example Ex 12 A heater assembly according to any preceding Example, wherein the porous body comprises a longitudinal surface extending between the liquid absorption surface and the heating surface, the longitudinal surface being liquid impermeable.
  • Example Ex 13 A heater assembly according to Ex12, further comprising at least one longitudinal groove extending along the longitudinal surface of the porous body between the liquid absorption surface and the heating surface.
  • Example Ex 14 A heater assembly according to any preceding Example, wherein the liquid absorption surface of the porous body has an area that is different to an area of the heating surface of the porous body.
  • Example Ex 15 A heater assembly according to any preceding Example, wherein the area of the heating surface of the porous body is less than the area of the liquid absorption surface of the porous body.
  • Example Ex 16 A heater assembly according to any preceding Example, wherein a ratio of the area of the heating surface of the porous body to the area of the liquid absorption surface of the porous body is less than or equal to 0.9.
  • Example Ex 17 A heater assembly according to any preceding Example, wherein a ratio of the area of the heating surface of the porous body to the area of the liquid absorption surface of the porous body is at least 0.1.
  • Example Ex 18 A heater assembly according to any preceding Example, wherein a ratio of the area of the heating surface of the porous body to the area of the liquid absorption surface of the porous body is between 0.1 and 0.9.
  • Example Ex 19 A heater assembly according to any preceding Example, wherein the porous body has a rectangular or a circular cross sectional shape.
  • Example Ex 20 A heater assembly according to any preceding Example, wherein the heating surface of the porous body is curved along one or both of a first transverse direction and a second transverse direction, the first transverse direction being orthogonal to the second transverse direction.
  • Example Ex 21 A heater assembly according to any preceding Example, wherein the heating surface is convex in one or both of the first transverse direction and the second transverse direction.
  • Example Ex 22 A heater assembly according to any preceding Example, further comprising a thermally insulating layer having a lower thermal conductivity than the porous ceramic body, wherein the thermally insulating layer is disposed between and is in contact with each of the porous ceramic body and the heating element, and the thermally insulating layer is configured to reduce heat transfer from the heating element to the porous ceramic body.
  • Example Ex 23 A heater assembly according to Ex22, wherein the thermally insulating layer comprises a thermally insulating material, the thermally insulating material having a lower thermal conductivity than the porous ceramic body.
  • Example Ex 24 A heater assembly according to Ex22 or Ex23, wherein the thermally insulating layer comprises a material having a thermal conductivity of less than 40 Watt per metre-Kelvin.
  • Example Ex 25 A heater assembly according to any one of Examples 22 to 24, wherein the thermally insulating layer comprises a material having a thermal conductivity of less than 10 Watt per metre-Kelvin.
  • Example Ex 26 A heater assembly according to any one of Examples 22 to 25, wherein the thermally insulating layer comprises a thermally insulating material, the thermally insulating material having a higher porosity than the porous ceramic body.
  • Example Ex 27 A heater assembly according to any preceding Example, wherein the heating element comprises a track defining a path across the heating surface of the porous ceramic body.
  • Example Ex 28 A heater assembly according to any preceding Example, wherein the heating element comprises a plurality of tracks or track portions arranged with a distance between at least two of the plurality of tracks or track portions in the range 200 to 300 micrometres.
  • Example Ex 29 A heater assembly according to any preceding Example, wherein the heating element comprises a plurality of tracks or track portions arranged electrically in parallel.
  • Example Ex 30 A heater assembly according to any preceding Example, wherein the heating element comprises a plurality of tracks or track portions defining a path having at least one bend, the inner edge of the bend being curved.
  • Example Ex 31 A heater assembly according to any preceding Example, wherein the heating element and the porous body are moulded as a single monolithic piece.
  • Example Ex 32 A heater assembly according to any preceding Example, wherein the heating element is a doped portion of the porous body.
  • Example Ex 33 A cartridge for an aerosol-generating system, the cartridge comprising a heater assembly according to any of preceding Example; and a liquid storage portion configured to hold a liquid aerosol-forming substrate; wherein the liquid storage portion is arranged at the liquid absorption surface of the porous body.
  • Example Ex 34 An aerosol-generating system comprising: a cartridge according to Ex33; and an aerosol-generating device comprising a power supply for supplying power to the heater assembly and control circuitry for controlling the supply of power from the power supply to the heater assembly; wherein the cartridge is removably couplable to the aerosolgenerating device.
  • Example Ex 35 An aerosol-generating system according to Ex34, further comprising an air inlet and an aerosol outlet, the air inlet being in fluid communication with the aerosol outlet to define an airflow pathway through the aerosol-generating system; wherein the heater assembly is arranged in fluid communication with the airflow pathway such that air flows past the heater assembly in an average airflow direction, wherein the heater assembly and airflow pathway are arranged such that an angle between the average vapour emission direction and the average airflow direction is less than 135 degrees.
  • Figure 1 shows a perspective view of a first heater assembly according to the present invention
  • Figure 2 shows a perspective view of a second heater assembly according to the present invention
  • Figure 3 shows a perspective view of a third heater assembly according to the present invention
  • Figure 4 shows a plan view along the longitudinal axis of a third heater assembly according to the present invention
  • Figure 5 shows a plan view along a transverse axis of the third heater assembly according to the present invention
  • Figure 6 shows a plan view along the longitudinal axis of a fourth heater assembly according to the present invention
  • Figure 7 shows a plan view along a transverse axis of the fourth heater assembly according to the present invention
  • Figure 8 shows a portion of the heating surface of a heater assembly
  • Figure 9 shows a portion of the heating surface of a heater assembly according to the present invention.
  • Figure 10 shows a cross sectional schematic view of an aerosol-generating system according to the present invention.
  • the heater assembly 100 shown in Figure 1 is for use in an aerosol-generating system.
  • the heater assembly 100 comprises a heating element 120 for vaporising a liquid aerosolforming substrate, and a porous body 110 for conveying the liquid aerosol-forming substrate to the heating element 120.
  • the porous body 110 includes a liquid absorption surface 111 and a heating surface 112.
  • the heating element 120 is located on the heating surface 112.
  • the porous body 110 is cylindrical and is formed from a sintered ceramic.
  • the porous body 110 is formed from silicon carbide.
  • the porous body 110 includes open pores.
  • the open pores are longitudinal pores which generally extend from the liquid absorption surface 111 to the heating surface 112 of the porous body.
  • the pore size of the pores in the porous body 110 vary between the liquid absorption surface 111 and the heating surface 112.
  • the porous body 110 includes a heating end and a liquid absorption end, the heating surface 112 being disposed at the heating end, and the liquid absorption surface 111 being disposed at the liquid absorption end.
  • the porous body includes a first average pore size at the liquid absorption end, and a second average pore size at the heating end. The first average pore size is greater than the second average pore size.
  • the first pore size at the liquid absorption end is about 150 micrometres.
  • the second pore size at the heating end is about 20 micrometres.
  • the pore size varies linearly between the first pore size and the second pore size to provide a pore size gradient between the liquid absorption end and the heating end of the porous body 110.
  • the pore structure and pore size gradient in the porous body 110 is achieved by etching the pores into a portion of silicon carbide.
  • the heating element 120 is a resistive heating element comprising a track arranged in a serpentine manner on the heating surface 112 of the porous body 110.
  • the arrangement of the resistive heating element track in a serpentine manner allows fluid to pass between adjacent portions of the resistive heating element.
  • the distance between adjacent parallel portions of the track of the resistive heating element is 250 micrometres. In this way, the resistive heating element may be described as fluid impermeable.
  • the resistive heating element comprises an electrically conductive material deposited on to the heating surface 112 of the porous body 110.
  • the electrically conductive material includes stainless steel.
  • the porous body 110 further comprises a longitudinal surface 113 extending between the liquid absorption surface 111 and the heating surface 112.
  • the longitudinal surface 113 includes a liquid impermeable coating.
  • the heater assembly 200 shown in Figure 2 includes most of the same features as the heater assembly 100 shown in Figure 1 and like reference numerals are used to refer to the same features.
  • the heater assembly 200 shown in Figure 2 differs from the heater assembly 100 shown in Figure 1 since it comprises a first porous material 121 and a second porous material 122.
  • the first porous material 121 is disposed at the liquid absorption end of the porous body 110.
  • the second porous material 122 is disposed at the heating end of the porous body 110.
  • the average pore size of the first porous material 121 is larger than the average pore size of the second porous material 122.
  • the average pore size of the first porous material 121 is substantially constant across the first porous material 121.
  • the average pore size of the second porous material 122 is substantially constant across the second porous material 122.
  • the heater assembly 150 of Figure 2 does not include a gradual pore size gradient between the liquid absorption surface 111 and the heating surface.
  • the heater assembly 200 of Figure 2 includes a step- wise change in average pore size at the interface between the first porous material 121 and the second porous material 122.
  • the average pore size of the first porous material 121 is about 150 micrometres.
  • the average pore size of the second porous material 122 is about 20 micrometres.
  • the heater assembly 300 shown in Figure 3 includes most of the same features as the heater assembly 100 shown in Figure 1 and like reference numerals are used to refer to the same features.
  • the heater assembly 300 shown in Figure 3 differs from the heater assembly 100 shown in Figure 1 since the heating surface 112 of the porous body 110 is curved in a convex direction along both of a first transverse direction and a second transverse direction, the first transverse direction being orthogonal to the second transverse direction.
  • the heating surface 112 is curved in a convex manner.
  • the heater assembly 400 shown in Figures 4 and 5 include most of the same features as the heater assembly 100 shown in Figure 1 and like reference numerals are used to refer to the same features.
  • Figure 4 shows a plan view of the heater assembly 400 viewed along the longitudinal direction towards the heating surface 112.
  • Figure 5 shows a plan view of the heater assembly 400 viewed along a transverse direction.
  • the heater assembly 400 shown in Figures 4 and 5 differs from the heater assembly 100 shown in Figure 1 since the area of the liquid absorption surface 111 of the porous body 110 is greater than the area of the heating surface 112 of the porous body 110. Both the liquid absorption surface 111 and the heating surface 112 are circular. In this way, the porous body 110 of the heater assembly 400 has the shape of a truncated cone.
  • the heater assembly 400 shown in Figures 4 and 5 further differs from the heater assembly 100 shown in Figure 1 since the heater element 120 in provided as a mesh of conductive material integrally formed with the porous body 110.
  • the heater assembly 500 shown in Figures 6 and 7 include most of the same features as the heater assembly 100 shown in Figure 1 and like reference numerals are used to refer to the same features.
  • Figure 6 shows a plan view of the heater assembly 500 viewed along the longitudinal direction towards the heating surface 112.
  • Figure 6 shows a plan view of the heater assembly 500 viewed along a transverse direction.
  • the heater assembly 500 shown in Figures 6 and 7 differs from the heater assembly 100 shown in Figure 1 since the area of the liquid absorption surface 111 of the porous body 110 is greater than the heating surface 112 of the porous body 110. Both the liquid absorption surface 111 and the heating surface
  • the porous body 110 of the heater assembly 500 has the shape of a truncated square based pyramid.
  • the longitudinal surface 113 of the porous body 110 is divided into four equally sized surfaces.
  • the porous body 110 of the heater assembly 500 further comprises a plurality of longitudinal grooves 510. Each of the four equally sized portions of the longitudinal surfaces
  • Each of the longitudinal grooves 510 extends from the liquid absorption surface 111 to the heating surface 112.
  • the longitudinal grooves 510 allows air entrained with aerosol generated at the heating surface 113 to pass along the longitudinal surface 113 of the porous body 110 to the liquid absorption surface 111 of the porous body 110.
  • Figures 8 and 9 shown schematic illustrations of current flow 800 around a corner of a track of a heating element 120.
  • Figure 8 is a schematic illustration of current flow 800 around a known heating element 120 in which a track portion defines a path having a bend, the inner edge of the bend having a sharp corner.
  • current flow depicted by arrows 800 which follows a path of least resistance, is concentrated (i.e., there is an increase in current density). This concentration occurs at an inner edge of the corner.
  • Current concentration can increase the local temperature, and can lead to the presence of hot spot at the corner.
  • a hot spot is disadvantageous, as it can affect the efficiency and reliability of the heating element.
  • a hot spot occurs despite the potential for local resistivity of the heater track material to increase due to a local increase in temperature (which would direct current flow away to a path of lower resistance).
  • Figure 9 is a schematic illustration of current flow 800 around a heating element 120 according to the invention in which a track portion defines a path having a bend, the inner edge of the bend being curved. In such a track, current flow 800 does not form a local hot spot.
  • current flow 800 in the smoother curved track portion as shown in Figure 9 remains more evenly distributed across the heating track, as depicted by dashed arrows 800.
  • Current flow 800 is guided to flow more evenly, to avoid a concentration of current at any point. This in turn limits hot spot creation.
  • the heater track may have a gradient of electrical resistivity perpendicular to current flow in a corner or corners, such that the electrical resistivity is higher at an inner part of the corner and lower at an outer part of the corner. Such a gradient is beneficial to counterbalance localized high current density and reduce hot spot creation.
  • FIG 10 is a schematic illustration of the interior of an aerosol-generating system 200 according to an example of the present disclosure.
  • the aerosol-generating system 200 comprises two main components, a cartridge 300 and a main body part or aerosol-generating device 400.
  • the cartridge 300 is removably connected to the aerosol-generating device 400.
  • the aerosol-generating device 400 comprises a device housing 401 that contains a power source in the form of a battery 402, which in this example is a rechargeable lithium ion battery, and control circuitry 403.
  • the aerosol-generating system 200 is portable and has a size comparable to a conventional cigar or cigarette.
  • a mouthpiece is arranged at a mouth end of the cartridge 300.
  • the cartridge 300 comprises a cartridge housing 304 containing a heater assembly 100 and a liquid reservoir or liquid storage portion 301 for holding a liquid aerosol-forming substrate.
  • Liquid aerosol-forming substrate is conveyed downwards from the liquid absorption surface 111 through the porous body to the heating element and vaporised aerosol-forming substrate is emitted from the heating surface 112 when electrical power is supplied to the heating element.
  • the cartridge 300 comprises one or more air inlets 302 formed in the cartridge housing 304 at a location along the length of the cartridge 300.
  • An aerosol outlet 305 is located in the mouthpiece at the mouth end of the cartridge 300.
  • the one or more air inlets 302 are in fluid communication with the aerosol outlet 305 to define an airflow pathway through the cartridge 300 of the aerosol-generating system 200.
  • the airflow pathway flows from the one or more air inlets 302 to the heater assembly 100 in an airflow channel.
  • the heater assembly 100 is arranged in fluid communication with the airflow pathway in the airflow channel. Air enters the one or more air inlets 302 and flows through the airflow channel past the heater assembly 100 in an average airflow direction.
  • the liquid storage portion 301 is annular in cross-section and is arranged around a central sealed aerosol channel 303.
  • the aerosol-generating system 200 is configured so that a user can puff or draw on the mouthpiece of the cartridge to draw aerosol into their mouth through the aerosol outlet 305.
  • air is drawn in through the one or more air inlets 302, along the airflow pathway through the airflow channel, past and around the heater assembly 100 and along the airflow pathway through the aerosol channel 303 to the aerosol outlet 305.
  • the control circuitry 403 controls the supply of electrical power from the battery 402 to the cartridge 300 when the system is activated. This in turn controls the amount and properties of the vapour produced by the heater assembly 100.
  • the control circuitry 403 includes an airflow sensor (not shown) and supplies electrical power to the heater assembly 100 when user puffs are detected by the airflow sensor. This type of control arrangement is well established in aerosol-generating systems such as inhalers and e-cigarettes.

Landscapes

  • Resistance Heating (AREA)

Abstract

L'invention concerne un système de génération d'aérosol (200) comprenant : un ensemble dispositif de chauffage (100) comprenant : un élément chauffant pour vaporiser un substrat de formation d'aérosol liquide, et un corps poreux pour transporter le substrat de formation d'aérosol liquide jusqu'à l'élément chauffant. Le corps poreux a une surface d'absorption de liquide (111) et une surface chauffante (112). L'élément chauffant est situé sur la surface chauffante (112) du corps poreux. L'élément chauffant et le corps poreux sont formés d'un seul tenant. La taille moyenne des pores du corps poreux varie entre la surface d'absorption de liquide (111) et la surface chauffante (112). Le système de génération d'aérosol (200) comprend en outre une entrée d'air (302) et une sortie d'aérosol (305), l'entrée d'air (302) étant en communication fluidique avec la sortie d'aérosol (305) pour définir une voie d'écoulement d'air dans le système de génération d'aérosol (200). L'ensemble dispositif de chauffage (100) est agencé en communication fluidique avec la voie d'écoulement d'air de telle sorte que l'air s'écoule au-delà de l'ensemble dispositif de chauffage (100) dans une direction d'écoulement d'air moyenne, l'ensemble dispositif de chauffage (100) et la voie d'écoulement d'air étant agencés de telle sorte qu'un angle entre la direction d'émission de vapeur moyenne et la direction d'écoulement d'air moyenne soit inférieur à 135 degrés.
PCT/EP2024/058648 2023-03-29 2024-03-28 Ensemble dispositif de chauffage à corps poreux Pending WO2024200748A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202480018574.3A CN120936260A (zh) 2023-03-29 2024-03-28 具有多孔体的加热器组件

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP23165102.7 2023-03-29
EP23165102 2023-03-29

Publications (1)

Publication Number Publication Date
WO2024200748A1 true WO2024200748A1 (fr) 2024-10-03

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WO (1) WO2024200748A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170367411A1 (en) * 2016-06-20 2017-12-28 Fabien DUC Vaporiser assembly for an aerosol-generating system
US20210195952A1 (en) * 2017-10-13 2021-07-01 Hauni Maschinenbau Gmbh Evaporator unit for an inhaler, in particular for an electronic cigarette product
US20210204600A1 (en) * 2018-05-31 2021-07-08 Philip Morris Products S.A. Heater assembly with pierced transport material
US20220030942A1 (en) * 2019-03-21 2022-02-03 Nerudia Limited Aerosol delivery system
WO2023040836A1 (fr) * 2021-09-14 2023-03-23 深圳麦克韦尔科技有限公司 Dispositif d'atomisation électronique et atomiseur associé

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170367411A1 (en) * 2016-06-20 2017-12-28 Fabien DUC Vaporiser assembly for an aerosol-generating system
US20210195952A1 (en) * 2017-10-13 2021-07-01 Hauni Maschinenbau Gmbh Evaporator unit for an inhaler, in particular for an electronic cigarette product
US20210204600A1 (en) * 2018-05-31 2021-07-08 Philip Morris Products S.A. Heater assembly with pierced transport material
US20220030942A1 (en) * 2019-03-21 2022-02-03 Nerudia Limited Aerosol delivery system
WO2023040836A1 (fr) * 2021-09-14 2023-03-23 深圳麦克韦尔科技有限公司 Dispositif d'atomisation électronique et atomiseur associé

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