EP4694710A1

EP4694710A1 - Heater assembly with separating element

Info

Publication number: EP4694710A1
Application number: EP23723111.3A
Authority: EP
Inventors: Ruilong HU; Baofeng Xie
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-04-14
Filing date: 2023-04-14
Publication date: 2026-02-18
Also published as: KR20250174066A; CN121001594A; WO2024212221A1; JP2026512446A

Abstract

A heater assembly (120) for an aerosol-generating system (100), the heater assembly comprising a heating element (134) for vaporising a liquid aerosol-forming substrate, a porous body (132) configured to convey liquid aerosol-forming substrate to the heating element, the porous body comprising a heating surface and a back surface opposing the heating surface, wherein the heating element is positioned on the heating surface and a heater holder (130) comprising a first cavity for supporting the porous body, a second cavity in fluid communication with an air outlet, and an integral separating element (126) for separating the first cavity from the second cavity, wherein the separating element covers the back surface of the porous body to prevent fluid communication between the back surface of the porous body and the air outlet.

Description

HEATER ASSEMBLY WITH SEPARATING ELEMENT

The present disclosure relates to a heater assembly for an aerosol-generating system; a cartridge for an aerosol-generating system; and an aerosol-generating system.
Aerosol-generating systems that vaporise a liquid aerosol-forming substrate to generate an aerosol for user inhalation are known in the art. The aerosol-generating systems typically comprise a heater assembly for heating the liquid aerosol-forming substrate. The liquid aerosol-forming substrate is heated and vaporised by the heater assembly to form a vapour. The vapour cools and condenses to form an aerosol, and this aerosol is then inhaled by a user. Such aerosol-generating systems are typically handheld and comprise a power supply for supplying power to the heater assembly and a reservoir for holding a supply of the liquid aerosol-forming substrate. Some aerosol-generating systems comprise an aerosol-generating power supply unit and a cartridge that is configured to be used with the power supply unit. When the aerosol-generating system comprises an aerosol-generating power supply unit and a cartridge, the heater assembly and liquid reservoir form part of the cartridge.
The heater assembly can comprise a heating element and wicking element, such as a porous body, that conveys liquid aerosol-forming substrate to the heating element. The aerosol-generating systems comprise an air inlet that allows air to be drawn into the system by a user applying a negative pressure at an air outlet. An airflow path is defined between the air inlet and the air outlet. The vapour produced at the heating element is entrained by the airflow and is condensed by the air to form an aerosol. The entrained aerosol is carried to the air outlet by the negative pressure applied at the air outlet.
Aerosol-forming substrate that is entrained without first being vapourised can lead to droplets of aerosol-forming substrate that have not been aerosolised, which undesirably become entrained in the air being drawn to the air outlet. These droplets are then delivered to the user at the air outlet.
It would be desirable to provide a heater assembly for a aerosol-generating system in which non-aerosolised liquid is not drawn through the air outlet.
According to an aspect of the present disclosure, there 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 configured to convey liquid aerosol-forming substrate to the heating element. The porous body may comprise a heating surface and a back surface opposing the heating surface. The heating element may be positioned on the heating surface. The heater assembly may further comprise a heater holder comprising a first cavity for supporting the porous body and a second cavity in fluid communication with an air outlet. The heater holder may comprise an integral separating element for separating the first cavity from the second cavity. The separating element may cover the back surface of the porous body to prevent fluid communication between the back surface of the porous body and the air outlet.
In use, the aerosol-forming substrate is vapourised by the heating element at the heating surface. The vapour is entrained in a flow of air such that the vapour condenses to form an aerosol, which is drawn out of the air outlet when a negative pressure is applied to the air outlet. The separating element may prevent fluid communication between the back surface of the porous body and the air outlet. In this way, the liquid aerosol-forming substrate present in the porous body is prevented from exiting the back surface of the porous body and entering the airflow and subsequently being drawn out of the air outlet. As such, the separating element may prevent droplets of liquid aerosol-forming substrate that have not been aerosolised from exiting the back surface of the porous body and being drawn through the air outlet.
Advantageously, the integral separating element may maintain the porous body within the heater holder. The mechanical stability of the porous body within the heater holder is improved by the separating element.
The heater holder may comprise one or more sealing element on an outer surface of the heater holder. The sealing element may be configured to form a seal with a portion of the aerosol-generating system with which the heater holder is engaged. The sealing element may be configured to reduce or prevent flow of liquid aerosol-forming substrate past the sealing element.
The separating element may be in contact with the back surface of the porous body. Advantageously, the separating element may provide structural support for the porous body.
The separating element may be non-planar. As used herein “planar” means substantially in the form of a plane, whereas “non-planar” means deviating from a plane.
The separating element may comprise a first surface facing the back surface of the porous body and an opposing second surface facing the air outlet.
The first surface of the separating element may be planar. The back surface of the porous body may be planar. The back surface of the porous body may be parallel to the first surface of the separating element.
The second surface of the separating element may be non-parallel to the first surface. The second surface of the separating element may be non-planar.
The shortest distance between the second surface of the separating element and the air outlet may be greater at a central portion of the separating element than it is at a periphery of the separating element. Advantageously, the greater shortest distance at the central portion may allow a sufficient amount of air and aerosol to flow through the second cavity and through the air outlet. The lesser shortest distance at the periphery of the central portion may provide the separating element with structural integrity.
The thickness of the separating element may be greater at a periphery of the separating element that it is at a central portion. The thickness of the separating element may be the distance between the first surface of the separating element and the second surface of the separating element in a direction normal to the back surface of the porous body. Advantageously, this may provide mechanical strength to the separating element. The heater holder, including the separating element, may be obtained by injection moulding. Advantageously, the above mentioned thickness of the separating element may facilitate the manufacturing of the heater holder by injection moulding.
The separating element may have a “V” -shaped cross-section. The second surface of the separating element may have a “V” -shaped cross-section. That is, the second surface of the separating element may comprise a turn or a fold. The turn or fold may have an angle of less than 180 degrees. The turn or fold may have an angle of 45 degrees or greater.
The separating element may be “U” -shaped. Preferably, the second surface of the separating element is “U” -shaped. The second surface of the separating element may comprise a gradual change of direction or turn. The second surface may comprise an arc shape. The second surface may comprise a turn to provide two sides facing each other with a third side therebetween to form a substantially “U” shape cross-section. The third side may be planar. The third side may be non-planar. The non-planar third side may have an arcuate cross-section.
The second surface of the separating element may be concave.
The distance between the separating element and the air outlet may affect the resistance to draw (RTD) of the heater assembly. The distance between the separating element and the air outlet may be arranged to provide sufficient RTD. In particular, the distance between the second surface of the separating element and the air outlet may be arranged to provide sufficient RTD. Preferably, the RTD of an aerosol-generating system comprising the heater assembly is from 400 to 600 Pascals..
Preferably, the maximum distance between separating element and the air outlet may be between 2.5 and 3.5 millimetres. More preferably the maximum distance between separating element and the air outlet may be between 2.85 and 3.05 millimetres. Preferably, the maximum distance between the second surface of the separating element and the air outlet may be between 2.5 and 3.5 millimetres. More preferably the maximum distance the second surface of the separating element and the air outlet may be between 2.85 and 3.05 millimetres.
The heater assembly may comprise an air inlet in fluid communication with the air outlet. An airflow path may be defined between the air inlet and the air outlet.
The separating element may separate the back surface of the porous body from a portion of the airflow path that extends between separating element and the air outlet.
The heating element and the heating surface of the porous body may be at least partly positioned in and in fluid communication with the airflow path.
The porous body may comprise third and fourth surfaces. The third and fourth surfaces may be adjacent to and extend between the heating surface and the back surface. The third and fourth surfaces may be at least partly positioned in and in fluid communication with the airflow path. In use, when air is drawn through the heater holder, the air may flow across the heating element and the heater holder, and across both the third and fourth surfaces of the porous body. The air may then enter the second cavity of the heater holder, and then be drawn out of the heater holder through the air outlet. The air may be prevented from contacting the back surface of the heater holder by the separating element.
The heater holder may comprise apertures aligned with the third surface and the fourth surface of the porous body. The heater holder may comprise a first aperture aligned with the third surface and a second aperture aligned with the fourth surface of the porous body. When present in an aerosol-generating system, the portion of the air flow in contact with the third and fourth surfaces of the porous body may also be in contact with other elements of the aerosol-generating system, outside of the heater holder, by way of the first aperture aligned with the third surface and the second aperture aligned with the fourth surface of the porous body. For example, if the heater holder is received in a housing, a portion of the airflow path may be defined between the third surface of the porous body and an inner surface of the housing, and a portion of the airflow path may be defined between the fourth surface of the porous body and an inner surface of the housing.
The heater holder may comprise holes defined through a surface of the heater holder and aligned with the second cavity. The holes may allow air that is outside of the heater holder to enter the second cavity. The heater holder may comprise a first hole aligned with a first side of the second cavity and a second holder aligned with a second side of the second cavity.
The first aperture may be adjacent to the first hole. The second aperture may be adjacent to the second hole. The first aperture may be the first hole. The second aperture may be the second hole.
The heater holder may comprise one or more liquid passages extending from the reservoir to the porous body. The one or more liquid passages may allow liquid from the reservoir to enter the porous body. The heater holder may comprise two liquid passages, positioned on either side of the air outlet.
The heater holder may be made of a material with sufficient stiffness to prevent deformation of the heater holder during use. Preferably, the material of the heater holder has a Shore A hardness from 60 to 80. More preferably, the material of the heater holder has a Shore A hardness from 65 to 75. In particularly preferred embodiments, the material of the heater holder has a Shore A hardness of 70.
As used herein, the term “Shore A hardness” is used to describe the durometer hardness of a rubber-like material, and is assessed in accordance with ASTM D2240 (2015) . The test effectively measures the penetration of a specified indentor into a specimen of the material under specified conditions of force and time. To this purpose, the specimen is placed on a hard flat surface. The indentor for the instrument is then pressed into the specimen making sure that it is parallel to the surface. The hardness is read within one second of firm contact with the specimen. The test specimens are generally 6.4 millimetres thick. It is possible to pile several specimens to achieve a thickness of 6.4 millimetres, but use of one specimen is preferred.
The heater holder may comprise an elastomeric material. The heater holder may be formed from an elastomeric material. The heater holder may be formed entirely from an elastomeric material. The heater holder may be formed from a thermoplastic elastomer. Preferably, the heater holder is formed from a thermoplastic elastomer having a Shore A hardness of between 60 and 80. Advantageously, a the heater holder is sufficiently robust to protect the porous body and is resistant to deformation. Advantageously, the heater holder is flexible enough to be inserted into part of an aerosol-generating system.
The heater holder may be formed from two or more materials. The two or more materials may be co-moulded to form the heater holder. For example, the one or more sealing element can be formed from a softer material than a main body of the heater holder.
The porous body may be a porous ceramic body. The porous body may comprise porous ceramic body or a porous glass body. In other words, the porous body may be a body comprising a porous ceramic, the porous ceramic having a plurality of pores, wherein at least some of the plurality of pores are interconnected. The porous body may be a body comprising a porous glass, the porous glass having a plurality of pores, wherein at least some of the plurality of pores are interconnected.
The heating element may be an electrical heating element. For example, the heating element may be 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. Examples of suitable metal alloys include stainless steel, constantan, nickel-, cobalt-, chromium-, aluminium-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, iron-aluminium based alloys and iron-manganese-aluminium based alloys. 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. In a preferred example, the electrical heating element may comprise one of more of NiCr and TiZr.
The heating element may have any suitable shape or form. Examples of suitable shapes and forms of the heating element include but are not limited to a band, a strip, a filament, a wire, a mesh, a spiral coil, fibres or a fabric.
The heating element may be located on and bonded to the heating surface of the porous body.
The heating element may be a metallic heating element, such as a metallic heating track.
The metallic track may comprise Ag-Pd alloy or Fe-Si alloy.
The heating element may comprise electrical contacts at opposite ends of the heater element. Advantageously, the heater holder is configured to expose the electrical contacts. This allows connection of the electrical contacts to a power supply.
According to another aspect of the present disclosure, there is provided a cartridge for an aerosol-generating system. The cartridge may comprise a heater assembly, in accordance with the present disclosure, and a housing. The housing may define a reservoir containing a liquid aerosol-forming substrate. The heater holder may comprise one or more sealing element on outer surface of the heater holder that engage the housing to seal the reservoir.
As described above, the one or more sealing element may be configured to form a seal with the housing to reduce or prevent flow of liquid aerosol-forming substrate past the sealing element. The one or more sealing element may extend around an outer circumference of the heater holder. The one or more sealing element may engage the inner surface of the housing around an inner circumference of the housing.
Advantageously, the housing is formed from a housing material. The cartridge housing may be formed from a durable material. The housing may be formed from a liquid impermeable material. Preferably, the housing material has a Shore A hardness greater that the Shore A hardness of the heater holder. More preferably, the housing material has a Shore A hardness greater than 80. In particularly preferred embodiments, the material of the housing has a Shore A hardness of 85. The housing may be formed from a mouldable plastics material, such as polypropylene (PP) or polyethylene terephthalate (PET) . The housing material may be polyether ether ketone (PEEK) or Tritan.
The cartridge may have a mouthpiece arranged at a mouth end of the cartridge. The mouthpiece may have a cartridge air outlet through which generated aerosol may be drawn by a user. The cartridge air outlet may be in fluid communication with the air outlet of the heater assembly. The cartridge may have a connection end configured to couple the cartridge to an aerosol-generating power supply unit.
The heater holder may comprise one or more liquid passages extending from the reservoir to the porous body. This allows liquid from the reservoir to enter the porous body from where it can be vaporised by the heating element.
According to a further aspect of the present disclosure, there is provided a aerosol-generating system. The aerosol-generating system may comprise a heater assembly in accordance with the present disclosure, and a housing. The housing may define a reservoir containing a liquid aerosol-forming substrate. The heater holder may comprise one or more sealing elements on an outer surface of the heater holder that engage the housing to the seal the reservoir. The aerosol-generating system may comprise a power supply configured to provide power to the heating element.
The aerosol-generating system may comprise an air inlet in fluid communication with the air outlet, and an air flow path defined between the air inlet and the air outlet. The airflow path may extend across a surface of the heating element and the heating surface of the porous body.
The porous body may comprise third and fourth surfaces. The third and fourth surfaces may be adjacent to and extend between the heating surface and the back surface. The third and fourth surfaces may be at least partly positioned in and in fluid communication with the airflow path. A portion of the airflow path may extend across the third surface and the fourth surface. In use, when air is drawn through the heater holder, the air may flow across the heating element and the heater holder, and across both the third and fourth surfaces of the porous body.
The heater holder may comprise apertures aligned with the third surface and the fourth surface of the porous body. The heater holder may comprise a first aperture aligned with the third surface and a second aperture aligned with the fourth surface of the porous body. The portion of the air flow in contact with the third and fourth surfaces of the porous body may also be in contact with an inner surface of the housing. A portion of the airflow path may be defined between the third surface of the porous body and an inner surface of the housing, and a portion of the airflow path may be defined between the fourth surface of the porous body and an inner surface of the housing.
The heater holder may comprise holes defined through a surface of the heater holder and aligned with the second cavity. The holes may allow the airflow path to extend into the second cavity. The holes may allow air that is outside of the heater holder to enter the second cavity. The heater holder may comprise a first hole aligned with a first side of the second cavity and a second holder aligned with a second side of the second cavity.
The first aperture may be adjacent to the first hole. The second aperture may be adjacent to the second hole. The first aperture may be the first hole. The second aperture may be the second hole.
As described above, the one or more sealing element may be configured to form a seal with the housing to reduce or prevent flow of liquid aerosol-forming substrate past the sealing element. The one or more sealing element may extend around an outer circumference of the heater holder. The one or more sealing element may engage the inner surface of the housing around an inner circumference of the housing.
Advantageously, the housing is formed from a housing material. The cartridge housing may be formed from a durable material. The housing may be formed from a liquid impermeable material. Preferably, the housing material has a Shore A hardness greater that the Shore A hardness of the heater holder. More preferably, the housing material has a Shore A hardness greater than 80. In particularly preferred embodiments, the material of the housing has a Shore A hardness of 85. The housing may be formed from a mouldable plastics material, such as polypropylene (PP) or polyethylene terephthalate (PET) . The housing material may be polyether ether ketone (PEEK) or Tritan.
The power supply may be 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-Iron-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 aerosol-generating system may comprise control circuitry. The control circuitry may regulate the supply of electrical energy to the heating from the power supply.
The aerosol-generating system may be a handheld aerosol-generating system. The aerosol-generating system may be a handheld aerosol-generating system configured to allow a user to suck on a mouthpiece to draw an aerosol through a first air outlet. The aerosol-generating system may have a size comparable to a conventional cigar or cigarette. The aerosol-generating system may have a total length between about 25 mm and about 150 mm. The aerosol-generating system may have an external diameter between about 5 mm and about 30mm.
The aerosol-generating system may be a one-piece system that is disposed of once the liquid aerosol-forming substrate is exhausted. Alternatively, the aerosol-generating system may comprise a cartridge removably coupleable to a power supply unit. The cartridge may comprise the heater assembly and the housing. The power supply unit may comprise the power supply and the control circuitry. The cartridge may be configured to engage with the power supply unit in a longitudinal direction. The cartridge may have a connection end, for connecting with the power supply unit and a mouthpiece end opposite to the connection end.
As used herein, the term “aerosol” is used to describe a dispersion of solid particles, liquid droplets, or a combination of solid particles and liquid droplets, in a gas. The aerosol may be visible or invisible. The aerosol may include vapours of substances that are ordinarily liquid or solid at room temperature as well as solid particles, liquid droplets, or a combination of solid particles and liquid droplets.
As used herein, the term “liquid aerosol-forming substrate” is used to describe to a liquid substrate capable of releasing volatile compounds that may form an aerosol. Such volatile compounds may be released by heating the liquid aerosol-forming substrate. 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. Examples of 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 aerosol former. 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%.
As used herein, an “aerosol-generating system” means a system that generates an aerosol from one or more liquid aerosol-forming substrates.
As used herein, the term “heating element” is used to describe a component that generates heat and transfers heat energy to the liquid aerosol-forming substrate. It will be appreciated that the heating element may be located directly on the porous body or indirectly on the porous body. It will be appreciated that the heating element may be integrally formed with the porous body.
As used herein, the term “porous body” is used to describe a component that 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 of the heater assembly in accordance with the first aspect of the invention comprises a porous ceramic body or a porous glass body. The porous body may be a porous ceramic body or a porous glass body.
As used herein, the term “heating surface” refers to the surface of the porous body nearest to the heating element. The heating surface of the porous body may be in contact with the heating element.
The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.
Ex1. A heater assembly for an aerosol-generating system, the heater assembly comprising:
a heating element for vaporising a liquid aerosol-forming substrate;
a porous body configured to convey liquid aerosol-forming substrate to the heating element, the porous body comprising a heating surface and a back surface opposing the heating surface, wherein the heating element is positioned on the heating surface; and
a heater holder comprising a first cavity for supporting the porous body_, a second cavity in fluid communication with an air outlet, and an integral separating element for separating the first cavity from the second cavity,
wherein the separating element covers the back surface of the porous body to prevent fluid communication between the back surface of the porous body and the air outlet.
Ex2. The heater assembly according to Ex1, wherein the heater holder comprises one or more sealing element on an outer surface of the heater holder.
Ex3. The heater assembly according to Ex1 or Ex2, wherein the separating element is in contact with the back surface of the porous body.
Ex4. The heater assembly according to any one of examples Ex1 to Ex3, wherein the separating element is non-planar.
Ex5. The heater assembly according to any one of examples Ex1 to Ex4, wherein the separating element comprises a first surface facing the back surface of the porous body and an opposing second surface facing the air outlet.
Ex6. The heater assembly according to Ex5, wherein the second surface is non-parallel to the first surface.
Ex7. The heater assembly according to Ex5 or Ex6, wherein the first surface of the separating element is planar.
Ex8. The heater assembly according to Ex5, Ex6 or Ex7, wherein the second surface of the separating element is non-planar.
Ex9. The heater assembly according to any one of examples Ex5 to Ex8, wherein the shortest distance between the second surface of the separating element and the air outlet is greater at a central portion of the separating element than it is at a periphery of the separating element.
Ex10. The heater assembly according to Ex9, wherein the separating element is “V” -shaped.
Ex11. The heater assembly according to any one of examples Ex1 to Ex10, wherein the thickness of the separating element is greater at a periphery of the separating element that it is at a central portion of the separating element.
Ex12. The heater assembly according to anyone of examples Ex1 to Ex11, wherein the distance between the separating element and the air outlet is arranged to provide sufficient RTD.
Ex13. The heater assembly according to any one of examples Ex1 to Ex12, wherein the maximum distance between separating element and the air outlet is between 2.5 millimetres and 3.5 millimetres.
Ex14. The heater assembly according to Ex13, wherein the maximum distance between separating element and the air outlet is between 2.95 millimetres and 3.05 millimetres.
Ex15. The heater assembly according to any one of examples Ex1 to Ex14, comprising an air inlet in fluid communication with the air outlet, and an airflow path defined between the air inlet and the air outlet.
Ex16. The heater assembly according to Ex15, wherein the separating element separates the back surface of the porous body from a portion of the airflow path that extends between separating element and the air outlet.
Ex17. The heater assembly according to Ex15 or Ex16, wherein the heating element and the heating surface of the porous body are at least partly positioned in and in fluid communication with the airflow path.
Ex18. The heater assembly according to any one of examples Ex15 to Ex17, wherein the porous body comprises third and fourth surfaces which are at least partly positioned in and in fluid communication with the airflow path.
Ex19. The heater assembly according to Ex18, wherein the heater holder comprises apertures aligned with the third surface and the fourth surface.
Ex20. The heater assembly according to any one of examples Ex1 to Ex19, wherein the heater holder is made of a material having a Shore A hardness of 70.
Ex21. The heater assembly according to any one of examples Ex1 to Ex20, wherein the heater holder material is a thermoplastic elastomer
Ex22. The heater assembly according to any one of examples Ex1 to Ex21, wherein the porous body is a porous ceramic body.
Ex23. The heater assembly according to any one of examples Ex1 to Ex22, wherein the heating element is bonded to the heating surface of the porous body.
Ex24. The heater assembly according to any one of examples Ex1 to Ex23, wherein the heating element is a metallic heating element, such as a metallic heating track.
Ex25. The heater assembly according to any one of examples Ex1 to Ex24, wherein the metallic track comprise Ag-Pd alloy or Fe-Si alloy.
Ex26. A cartridge for an aerosol-generating system, the cartridge comprising:
a heater assembly in accordance with any one of examples Ex1 to Ex25; and
a housing, the housing defining a reservoir containing a liquid aerosol-forming substrate,
wherein the heater holder comprises one or more sealing element on outer surface of the heater holder that engage the housing to seal the reservoir.
Ex27. An aerosol-generating system, comprising:
a heater assembly in accordance with any one of examples Ex1 to Ex25;
a housing, the housing defining a reservoir containing a liquid aerosol-forming substrate, wherein the heater holder comprises one or more sealing elements on an outer surface of the heater holder that engage the housing to the seal the reservoir; and
a power supply configured to provide power to the heating element.
Ex28. The aerosol-generating system according to Ex27, comprising an air inlet in fluid communication with the air outlet, and an air flow path defined between the air inlet and the air outlet, wherein a portion of the airflow path extends across a surface of the heating element and the heating surface of the porous body.
Ex29. The aerosol-generating system according to Ex28, wherein the porous body comprises third and fourth surfaces, wherein the airflow path extends across the third and fourth surfaces. Ex30. The aerosol-generating system according to Ex29, wherein the heater holder comprises apertures aligned with the third surface and the fourth surface, such that the airflow path is in contact with an inner surface of the housing.
Ex31. The aerosol-generating system according to Ex30, wherein the heater holder comprises holes aligned with the second cavity such that the airflow path extends into the second cavity.
Examples will now be further described with reference to the accompanying Figures, wherein:
Figure 1A shows a schematic cross-sectional view of an aerosol-generating system according to the present disclosure;
Figure 1B shows a schematic cross-sectional view of the aerosol-generating system of Figure 1A in a use configuration;
Figure 2 shows a cross-sectional view of a heater assembly according to the present disclosure;
Figure 3 shows a perspective view of a heater holder according to the present disclosure;
Figure 4 shows a perspective view of a heater assembly according to the present disclosure;
Figure 5A shows a perspective view of the porous body and heating element; and
Figure 5B shows an alternative perspective view of the porous body of Figure 5A.
Figure 1A shows a schematic cross-sectional view of an aerosol-generating system 100 according to the present disclosure. The aerosol-generating system 100 comprises a housing 110, a heater assembly 120, and a power supply unit 150. Figure 1A shows the cartridge 140 uncoupled from the power supply unit 150.
The housing 110 and heater assembly 120 assembled together form the cartridge 140. The cartridge 140 is reversibly couplable to the power supply unit 150 to form the aerosol-generating system 100. The cartridge 140 coupled to the power supply unit 150 provides the use configuration of the aerosol-generating system 100, which is shown in Figure 1B. Alternatively, the system 100 may be provided as a singular aerosol-generating device comprising the housing 110, heater assembly 120, and power supply unit 150 assembled together rather than as a separable cartridge and power supply unit.
The housing 110 comprises an outer wall formed from a polymer. An example polymer may be Tritan or polyether ether ketone (PEEK) . The outer wall of the housing 110 defines a liquid reservoir 116 for containing liquid aerosol-forming substrate.
The housing 110 further comprises an airflow passage 112 located that passes within the reservoir 116. The airflow passage 112 extends from a proximal end of the housing 110 towards a distal end of the housing 110. The wall defining the airflow passage 112 is also formed from a polymer or a copolymer, for example Tritan. The airflow passage 112 comprises a housing airflow outlet 114. The housing airflow outlet 114 is defined at a proximal end of the airflow passage 112 and the proximal end of the housing 100. The airflow passage 112 is positioned substantially centrally within the housing 110.
The cartridge 140 comprises the heater assembly 120, which comprises a heater holder 130, a porous body 132, and a heating element 134. The porous body 132 and the heating element 134 may together be referred to as a heater. The porous body 132 is a ceramic porous body configured to convey the liquid aerosol-forming substrate to the heating element 134. The porous body 132 comprises a heating surface on which the heating element 134 is positioned, and a back surface opposing the heating surface. The heating element 134 is an electrically resistive heating element. The heater assembly 120 is more clearly illustrated in and described with reference to Figure 2, and the porous body is more clearly illustrated in and described with reference to Figures 5A and 5B.
As shown in Figure 1A, the heater holder 130 comprises two liquid passages 123, arranged on either side of an air outlet 122. The liquid passages extend between the liquid reservoir 116 and the porous body 132 to deliver liquid aerosol-forming substrate from the reservoir 116 to the porous body 132.
The heater holder 130 is positioned within and has an interference fit with the housing 110. The heater holder 130 has a sealing element 118, also known as a sealing rib, provided on its outer surface for forming a seal with an inner surface of the housing 110 to seal the reservoir 116. The sealing element 118 is provided to prevent liquid aerosol-forming substrate from leaking out of the liquid reservoir and into a gap between the heater holder 130 and the housing 110.
The heater holder also comprises a plurality of channels 108 formed between the outer surface of the heater holder and the inner surface of the housing on an opposite side of the sealing element 118 to the reservoir 116. The plurality of channels 108 are formed by protrusions formed on the outer surface of the heater holder 130. If any liquid does pass from the reservoir 116 past the sealing element 118 or leaks from the porous body 132 into the gap between the heater holder 130 and the housing 110, the plurality of channels 108 hold the liquid to reduce the risk of it leaking from the cartridge 140.
The heater holder 130 further comprises a first cavity for supporting the porous body 132 and a second cavity which is in fluid communication with an air outlet 122. The air outlet 122 is in fluid communication with the heater holder outlet 127, which leads to the airflow passage 112.
An integral separating element 126 separates the first cavity from the second cavity, and the separating element 126 covers the back surface of the porous body to prevent fluid communication between the back surface of the porous body 132 and the air outlet 122.
The cartridge 140 further comprises two cartridge electrical contacts 138. The cartridge electrical contacts 138 are configured to be accessible from the lower surface of the cartridge. Each cartridge electrical contact 138 is further configured to contact either end of the heating element 134, illustrated in more detail in Figure 5A. The two cartridge electrical contacts 138 comprise copper with a gold coating.
The two cartridge electrical contacts 138 are arranged on either side of a central air inlet 142, which allows air to enter the cartridge 140 and heater assembly 120.
The power supply unit 150 comprises a device cavity. The device cavity is defined by the power supply unit and 150 and is configured to receive a portion of the cartridge 140 when the cartridge is coupled to the power supply unit 150. The cartridge 140 is configured to be reversibly coupled to the power supply unit 150 by snap fitting.
The power supply unit 150 further comprises device electrical contacts 155 located on a lower surface of the device cavity. The device electrical contacts 155 are configured to contact the cartridge electrical contacts 145 when the cartridge 140 is coupled to the power supply unit 150. The two device electrical contacts 155 comprise copper with a gold coating. The power supply unit 150 further comprises control circuitry 154. The device electrical contacts 155 are connected to the control circuitry 154 via electrical wires. The power supply unit 150 further comprises a power supply 156. The power supply 156 comprises a rechargeable lithium ion battery, that is rechargeable via an electrical connector (not shown) at a distal end of the power supply unit 150. The power supply 156 is connected to the control circuitry 154 via electrical wires.
Figure 1B shows the aerosol-generating system 100 in a use configuration, wherein the cartridge 140 is coupled to the power supply unit 150. In use, the user may reversibly couple the cartridge 140 to the power supply unit 150 and decouple the cartridge 140 from the power supply unit 150, for example when the reservoir 116 is empty of liquid aerosol-forming substrate. The cartridge 140 may be coupled to the power supply unit 150 at a distal end of the cartridge by snap fitting.
When the cartridge 140 is coupled to the power supply unit 150, a small gap is present between the distal end of the cartridge 140 and the power supply unit 150. In use, air may enter the system air inlet 152. The system air inlet is in fluid communication with the air inlet 142.
When coupled to the power supply unit 150, a portion of the cartridge 140 is received within the device cavity, such that the device electrical contacts 155 are in contact with the cartridge electrical contacts 138. A complete electrical pathway is therefore formed from the device electrical contacts 155 to the cartridge electrical contacts 138, and then to the heating element 134.
In use, the user connects the cartridge 140 to the power supply unit 150 and presses a button (not shown) located on the side of the power supply unit 150 to activate the system. The button is connected to the control circuitry 154. The control circuitry 154 is configured to control the supply of power from the power supply 156 to the heating element 134 via the device electrical contacts 155 and the cartridge electrical contacts 138. When the user presses the button, power is supplied from the power supply 156 to the heating element 134, via the control circuity 154, the device electrical contact 155 and the cartridge electrical contacts 138, such that the temperature of the heating element 134 increases. The liquid aerosol-forming substrate in the reservoir 116 is drawn down the liquid passages 123 in the heater holder 130 to the porous body 132 of the heater assembly 120. The porous body 132 wicks the liquid aerosol-forming substrate to the heating surface of the ceramic body 132 where it is volatilised by the hot heating element 134.
When the user inhales upon the proximal end of the housing 110, air is drawn through the aerosol-generating system 100. In particular, air is drawn into the system through the system air inlet 152, and then through the cartridge air inlet 142. The air passes across the heating surface of the porous body 132 and the hot heating element 134, where the volatilised aerosol-forming substrate is entrained by the air. The volatilised aerosol-forming condenses within the flow of air through the cartridge 140 to form an aerosol. The airflow containing the aerosol travels past the porous body and through the air outlet 122. It is drawn into the mouth of the user via the airflow passage 112 and cartridge airflow outlet 114. This flow of air is illustrated in more detail in Figure 2.
The flow of air 172 passes through the cartridge 140 approximately perpendicular to a longitudinal direction of the system 100. The longitudinal direction of the system 100 is substantially parallel to the direction of air flow from the porous body 132, through the airflow passage 112 and to the cartridge airflow outlet 114.
Figure 2 shows a schematic cross-sectional view of the heater assembly of Figure 1. The heater assembly 120 comprises the heater holder 130, porous body 132, and the heating element 134.
As shown in Figure 2, the heater holder 130 comprises an air inlet 142 and an air outlet 122. An airflow path is defined between the air inlet 142 and the air outlet 122. The heater holder further comprises a heater holder outlet 127, which is in fluid communication with the air outlet 122 via a passage defined in the heater holder between the air outlet 122 and the heater holder outlet 127.
The heater holder comprises a first cavity 124 and a second cavity 128. The first cavity 124 is separated from the second cavity 128 by the separating element 126. The first cavity 124 supports the porous body, such that the porous body is retained within the heater holder 130. The separating element 126 covers and is in contact with a back surface of the porous body 132. The separating element 126 is non-planar. The separating element 126 comprises a first surface 121 facing the back surface of the porous body and an opposing second surface 125 facing the air outlet 122. The first surface 121 is planar and the back surface 125 is non-planar. The back surface 125 is non-parallel to the first surface 121.
The shortest distance between the second surface 125 of the separating element and the air outlet 122 is greater at a central portion of the separating element 126 than it is at a periphery of the separating element 126. The thickness of the separating element 126 is greater at a periphery of the separating element 126 that it is at a central portion. The maximum distance between the second surface of the separating element 126 and the air outlet 122 is between 2.85 millimetres and 3.05 millimetres. The distance between the second surface of the separating element 126 and the air outlet 122 provides a sufficient resistance to draw (RTD) of an aerosol-generating system comprising the heater assembly, such as an RTD from 400 to 600 Pascals.
When the heater assembly is positioned within an aerosol-generating system, as described above in relation to Figures 1A and 1B, an airflow may be established through the heater assembly during use of the aerosol-generating system. In such use, the airflow enters the heater assembly via the air inlet 142. The air passes across the heating surface of the porous body 132 and the heating element 134. The porous body comprises third and fourth surfaces extending between the heating surface and the back surface of the porous body. In use, the airflow passes around the porous body, passing across the third and fourth surfaces. The airflow then enters the second cavity 128. The airflow does not come into contact with the back surface of the porous body 132 because the separating element 126 covers the back surface of the porous body 132. The airflow flows across the second surface 125 of the separating element 126 and enters the air outlet 122. The airflow exits the heater holder through the heater holder outlet 127.
Figure 3 shows a schematic cross-sectional view of the heater holder 130 of the aerosol-generating system in Figure 1. The heater holder 130 is made from a thermoplastic elastomer having a Shore A hardness of 70. The heater holder 130 comprises a first cavity 124, a second cavity 128 and a separating element 126, which separates the first cavity 124 from the second cavity 128. The separating element 126 is integral to the heater holder 130.
The heater holder 130 comprises sealing elements 118, 119. The sealing elements 118, 119 are integral with and extend around an outer circumference of the heating holder 130 and are arranged to engage with the inner surface of another component of an aerosol-generating system, such as the housing 110 shown in Figure 1, to seal a liquid reservoir. First sealing elements 118 are arranged to prevent liquid aerosol-forming substrate from leaking out of the liquid reservoir and into a gap between the heater holder 130 and the housing 110. The heater holder further comprises second sealing elements 119. The second sealing elements are provided at an opposite end of the heater holder 130 to the first sealing elements 118. The second sealing elements provide a further barrier to liquid escaping from the cartridge as well as a barrier to contaminants entering the cartridge.
A porous body (not shown in Figure 3) is supported by the heater holder 130 in the first cavity 124. The separating element 126, integral with the heater holder 130, separates the porous body from the air outlet 122 and prevents liquid escaping from a rear surface of the porous body into the air flow.
Figure 4 shows a schematic isometric view of the heater assembly according to the present disclosure. The heater assembly 120 comprises the porous body 132, supported by a heater holder 130 within the first cavity 124 of the heater holder 130. The separating element 126 is in contact with and covers a back surface of the porous body 132.
The heater holder 130 comprises a holder outlet 127, which is in fluid communication with the air outlet 122 (not shown in Figure 4) . The heater holder 130 comprises two liquid passages 123 defined on either side of the holder outlet 127.
The liquid passages 123 are defined between the porous body 132 and the liquid reservoir of the aerosol-generating system. The liquid passages convey liquid from the liquid reservoir to the porous body 132.
The heater holder comprises two apertures defined through the heater holder on opposing sides of the heater holder 130. A first aperture is aligned with a third surface of the porous body 132 and a second aperture is aligned with a fourth surface of the porous body 132. The second aperture and fourth surface of the porous body 132 are on the opposite side of the heater holder 130, not visible in Figure 4. When present in an aerosol-generating system, a portion of the airflow pathway in contact with the third and fourth surfaces of the porous body is also in contact with other elements of the aerosol-generating system 100 outside of the heater holder 130, by way of the apertures aligned with the third surface and the fourth surface of the porous body.
Electrical contacts 338 are electrically connected to a heating element (not shown) that is positioned on the heating surface of the porous body 132.
In use, when the heater assembly 120 is present in an aerosol-generating system 100, the heater holder is arranged inside a housing as shown in Figures 1A and 1B. The portions of the airflow pathway that are in contact with the third surface and fourth surface of the porous body 132 are also in contact with an inner surface of the housing.
Figure 5A shows a schematic isometric view of a heater comprising the porous body and heating element and Figure 2B shows a schematic alternative isometric view of the heater.
The heating element 134 is illustrated as arranged on the lower, heating, surface of the porous body 132. The heating element comprises two heating element electrical contacts 135 at opposite ends of the heating surface 131 of the ceramic body 132. The two heating element electrical contacts 135 are configured to contact the cartridge electrical contacts 138, as is described above.
The heating element 134 further comprises a serpentine heating element pathway 133 extending between the two heating element electrical contacts135. The serpentine heating element pathway 133 is configured to be resistively heated when a current is passed through the serpentine heating element pathway 133. The heating element 134 is a metallic heating track comprising a film of metal. The two heating element electrical contacts 135 are integrally formed with the serpentine heating element pathway 133. For example, the heating element 134 can be made of Ag-Pd alloy or Fe-Si alloy.
Two liquid feed cut-outs 136 are defined in the porous body 132. Each of the two liquid feed cut-outs 136 are defined in back surface 137 at opposite ends of the porous body 132.
When the porous body 132 is positioned in the heater holder 130, the liquid aerosol-forming substrate flows from the heater holder liquid passages 123 into the corresponding liquid feed cut-outs 136, and subsequently into the porous body 132.
For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about" . Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± {10 %of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic (s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

A heater assembly for an aerosol-generating system, the heater assembly comprising:

a heating element for vaporising a liquid aerosol-forming substrate;

a porous body configured to convey liquid aerosol-forming substrate to the heating element, the porous body comprising a heating surface and a back surface opposing the heating surface, wherein the heating element is positioned on the heating surface; and

a heater holder comprising a first cavity for supporting the porous body_, a second cavity in fluid communication with an air outlet, and an integral separating element for separating the first cavity from the second cavity,

wherein the separating element covers the back surface of the porous body to prevent fluid communication between the back surface of the porous body and the air outlet.
The heater assembly according to claim 1, wherein the heater holder comprises one or more sealing element on an outer surface of the heater holder.
The heater assembly according to claim 1 or 2, wherein the separating element is in contact with the back surface of the porous body.
The heater assembly according to any preceding claim, wherein the separating element is non-planar.
The heater assembly according to any preceding claim, wherein the separating element comprises a first surface facing the back surface of the porous body and an opposing second surface facing the air outlet.
The heater assembly according to claim 5, wherein the first surface of the separating element is planar.
The heater assembly according to claim 6 or 7, wherein the second surface of the separating element is non-planar.
The heater assembly according to any one of claims 6, 7 or 8, wherein the perpendicular distance between the second surface of the separating element and the air outlet is greater at a central portion of the separating element than it is at a periphery of the separating element.
The heater assembly according to any preceding claim, wherein the thickness of the separating element is greater at a periphery of the separating element that it is at a central portion of the separating element.
The heater assembly according to any preceding claim, wherein the distance between the separating element and the air outlet is arranged to provide sufficient RTD.
The heater assembly according to any preceding claim, comprising an air inlet in fluid communication with the air outlet, and an airflow path defined between the air inlet and the air outlet, wherein the separating element separates the back surface of the porous body from a portion of the airflow path that extends between separating element and the air outlet.
The heater assembly according to any preceding claim, wherein the heater holder is made of a thermoplastic elastomer having a Shore A hardness of 70.
A cartridge for an aerosol-generating system, the cartridge comprising:

a heater assembly in accordance with any one of claims 1 to 12; and

a housing, the housing defining a reservoir containing a liquid aerosol-forming substrate, wherein the heater holder comprises one or more sealing element on outer surface of the heater holder that engage the housing to seal the reservoir.
An aerosol-generating system, comprising:

a heater assembly in accordance with any one of claims 1 to 12;

a housing, the housing defining a reservoir containing a liquid aerosol-forming substrate, wherein the heater holder comprises one or more sealing elements on an outer surface of the heater holder that engage the housing to the seal the reservoir; and

a power supply configured to provide power to the heating element.
The aerosol-generating system according to claim 14, comprising an air inlet in fluid communication with the air outlet, and an air flow path defined between the air inlet and the air outlet, wherein a portion of the airflow path extends across a surface of the heating element and the heating surface of the porous body.