Heater assembly with porous body

Abstract

An aerosol generating system (200) comprises a heater assembly (100) which includes a heating element for vaporizing a liquid aerosol-forming substrate and a porous body for transporting the liquid aerosol-forming substrate to the heating element. The porous body has a liquid-absorbing surface (111) and a heating surface (112). The heating element is located on the heating surface (112) of the porous body. The heating element and the porous body are integrally formed. The average pore size of the porous body varies between the liquid-absorbing surface (111) and the heating surface (112). The aerosol generating system (200) further comprises an air intake (302) and an aerosol outlet (305), the air intake (302) being in fluid communication with the aerosol outlet (305) defining an airflow path through the aerosol generating system (200). The heater assembly (100) is arranged in fluid communication with the airflow path so that air flows through the heater assembly (100) in the mean airflow direction, and the heater assembly (100) and the airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

Description

Technical Field

[0001] The present invention relates to a heater assembly for use in an aerosol generation system. In particular, the present invention relates to a heater assembly for use in an aerosol generation system, the heater assembly comprising a heating element and a porous body.

Background Art

[0002] Aerosol generation systems that heat a liquid aerosol-forming substrate to generate an aerosol to be delivered to a user are generally known in the prior art. These systems typically comprise an aerosol generator and a replaceable cartridge. The cartridge contains a liquid aerosol-forming substrate that can release a volatile compound when heated. The cartridge typically also includes a heater for heating the liquid aerosol-forming substrate. In known aerosol generation systems, the heater comprises a resistive heating element wound around a wick that supplies the liquid aerosol-forming substrate to the heating element. The aerosol generator or cartridge also comprises a mouthpiece. When the user inhales through the mouthpiece, an electric current flows through the heating element, heating the heating element by resistive heating or Joule heating, and as a result, heating the liquid aerosol-forming substrate supplied by the wick. Thereby, a volatile compound is released from the liquid aerosol-forming substrate and cooled to form an aerosol. The aerosol is then inhaled into the user's mouth through the mouthpiece.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Such known aerosol generation systems have many drawbacks. It is necessary to prevent "dry heating" or "dry puffing," which occurs when the heating element is heated while an insufficient liquid aerosol-forming substrate is supplied to it. During operation, it is preferable to maintain a supply of liquid aerosol-forming substrate to the heating element so that it remains moist, in order to ensure that a satisfactory aerosol is generated when the user inhales. Dry heating can lead to overheating of the heating element and potentially to thermal decomposition of the liquid aerosol-forming substrate, which may result in undesirable byproducts and, furthermore, unsatisfactory aerosol generation. Allowing the aerosol generation system to continue operating when the liquid aerosol-forming substrate is not supplied to the heating element can degrade the quality of the user experience.

[0004] Conversely, prior art aerosol generating systems have been found to be susceptible to leakage of the liquid aerosol-forming substrate. For example, if the liquid aerosol-forming substrate is supplied to the heating element at a rate faster than the rate at which it is vaporized by the heating element, the liquid aerosol-forming substrate may leak from one end of the core and from the system. This is waste of the aerosol-forming substrate and can contaminate other components of the aerosol generating system. Therefore, leakage of the liquid aerosol-forming substrate is undesirable.

[0005] It is desirable to provide a heater assembly that efficiently and consistently supplies a liquid aerosol-forming substrate to a heating element.

[0006] It is desirable to provide a heater assembly that reduces and prevents leakage of the liquid aerosol forming substrate. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows a perspective view of the first heater assembly according to the present invention. [Figure 2] Figure 2 shows a perspective view of a second heater assembly according to the present invention. [Figure 3] Figure 3 shows a perspective view of a third heater assembly according to the present invention. [Figure 4] Figure 4 shows a plan view of the third heater assembly according to the present invention, along the longitudinal axis. [Figure 5] Figure 5 shows a plan view of the third heater assembly according to the present invention, along its transverse axis. [Figure 6] Figure 6 shows a plan view of the fourth heater assembly according to the present invention, along the longitudinal axis. [Figure 7] Figure 7 shows a plan view of the fourth heater assembly according to the present invention, along its transverse axis. [Figure 8] Figure 8 shows a portion of the heating surface of the heater assembly. [Figure 9] Figure 9 shows a portion of the heating surface of the heater assembly according to the present invention. [Figure 10] Figure 10 shows a schematic cross-sectional view of the aerosol generation system according to the present invention. [Modes for carrying out the invention]

[0008] This disclosure provides a heater assembly for an aerosol generation system. The heater assembly may include a heating element for vaporizing a liquid aerosol-forming substrate. The heater assembly may include a porous body for transporting the liquid aerosol-forming substrate to the heating element. The porous body may have a liquid-absorbing 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 formed integrally. 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-absorbing surface and the heating surface.

[0009] According to a first aspect of the present invention, a heater assembly for an aerosol generating system is provided. The heater assembly comprises a heating element for vaporizing a liquid aerosol-forming substrate. The heater assembly comprises a porous body for transporting the liquid aerosol-forming substrate to the heating element. The porous body has a liquid-absorbing 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 are integrally formed. The average pore size of the porous body varies between the liquid-absorbing surface and the heating surface.

[0010] Providing a porous body that includes variations in pore size between the liquid-absorbing surface and the heating surface can, advantageously, help control the transport of the liquid aerosol-forming substrate from the storage portion to the heating element. Specifically, variations in pore size between the liquid-absorbing surface and the heating surface can enable the porous body to provide a consistent supply of the aerosol-forming substrate to the heating surface. This can, advantageously, avoid undesirable "dry heating." Furthermore, the porous body of the present invention can also, advantageously, prevent leakage of the liquid aerosol-forming substrate from the heating surface of the porous body.

[0011] Providing a heating element integrally formed with a porous body can, advantageously, provide a more robust and reliable connection between the heating element and the porous body. This can, advantageously, help improve heat transfer between the heating element and the porous body.

[0012] Integrating the heating element with the porous body also has the advantage of providing a heating element that is easier to manufacture and therefore can result in a more energy-efficient heating element that can generate a more consistent aerosol. This can provide users of the aerosol generating system with an improved and more enjoyable experience. Such arrangements can also help reduce the likelihood of users experiencing dry heating or dry puffing.

[0013] The advantage of integrally forming the heating element with the porous body is that it helps mitigate manufacturing tolerance issues that arise in core and coil heaters, as well as in other arrangements where the heating element is removed from the liquid transport element. The dimensions and arrangement of the heating element relative to the porous body are also fixed, which helps in more consistent aerosol production. This is because the heating element is fixed to the porous body, which helps to supply the heating element with the liquid aerosol-forming substrate. This also helps to prevent undesirable heat loss, which contributes to improved energy efficiency.

[0014] By integrally forming the heating element with the porous body, the resulting aerosol generation system can benefit from reduced material requirements. This is because the need for intermediate components to fix the heating element to the porous body can be reduced or completely eliminated. Material savings can lead to cost reductions for the entire aerosol generation system. A further benefit of reducing the materials required for the entire aerosol generation system is the provision of a more sustainable and environmentally friendly solution.

[0015] Since the heating element is formed integrally with the porous body, the heating surface of the porous body may not be a clearly defined surface. The porous body and the heating element may be fabricated from a single monolithic portion of the porous material. In this case, the heating element may be a portion of the porous material configured to generate heat. As will be described in more detail below, this can be achieved, for example, by doping a portion of the porous material or by diffusing a conductive material into the porous material. Thus, the heating surface of the porous body may represent an interface between a portion of the porous material configured to transport a liquid aerosol-forming substrate and a portion of the porous material configured to generate heat. Depending on how the heating element is formed, the heating surface of the porous body may be a stepped interface between a portion of the porous material configured to transport a liquid aerosol-forming substrate and a portion of the porous material configured to generate heat.

[0016] 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 larger at the liquid absorption surface than at the heating surface.

[0017] The porosity of the porous body at the liquid absorption surface may be at least 20 percent. For example, the porosity of the porous body at the liquid absorption surface may be at least 30 percent, at least 40 percent.

[0018] The porosity of the porous body at the liquid absorption surface may be 100 percent or less. For example, the porosity of the porous body at the liquid absorption surface may be 90 percent or less, 80 percent or less, 70 percent or less, 60 percent or less.

[0019] The porosity of the porous body at the liquid absorption surface may be from 20 percent to 90 percent. For example, the porosity of the porous body at the liquid absorption surface may be from 30 percent to 80 percent, from 40 percent to 70 percent, or from 40 percent to 60 percent. The porosity of the porous body at the liquid absorption surface may be about 50 percent.

[0020] The porosity of the porous body at the heating surface may be at least 20 percent. For example, the porosity of the porous body at the heating surface may be at least 30 percent, at least 40 percent.

[0021] The porosity of the porous body at the heating surface may be 100 percent or less. For example, the porosity of the porous body at the heating surface may be 90 percent or less, 80 percent or less, 70 percent or less, 60 percent or less.

[0022] The porosity of the porous material on the heated surface may be 20 percent to 90 percent. For example, the porosity of the porous material on the heated surface may be 30 percent to 80 percent, 40 percent to 70 percent, or 40 percent to 60 percent. The porosity of the porous material on the heated surface may be approximately 50 percent.

[0023] The porous body may have any length. The porous body may have a length of at least 0.5 millimeters. For example, the porous body may have a length of at least 1 millimeter, at least 2 millimeters, at least 3 millimeters, at least 4 millimeters, or at least 5 millimeters.

[0024] The porous body may have a length of 20 millimeters or less. For example, the porous body may have a length of 10 millimeters or less, 9 millimeters or less, 8 millimeters or less, 7 millimeters or less, or 6 millimeters or less.

[0025] The porous body may have a length of 0.5 mm to 20 mm. For example, the porous body may have a length of 1 mm to 10 mm, 2 mm to 9 mm, 3 mm to 8 mm, 4 mm to 7 mm, or 5 mm to 6 mm. The porous body may have a length of approximately 5 mm.

[0026] As used herein in relation to the present invention, the term "liquid aerosol-generating substrate" refers to a liquid substrate having the ability to release volatile compounds that can form aerosols. Such volatile compounds can be released by heating the aerosol-generating substrate.

[0027] As used herein in relation to the present invention, the term “heating element” refers to a component that transfers thermal energy to a liquid aerosol generating substrate. It is understood that an electric heating element may be placed directly on a porous body. Naturally, the heating element may also be part of the same porous material on which the porous body is formed.

[0028] As used herein in relation to the present invention, the term "porous body" refers to a component having a plurality of pores, at least a portion of which are interconnected. The porous body is configured to contain a liquid within the plurality of pores. The porous body may comprise a porous material.

[0029] As used herein in relation to the present invention, the term "heated surface" refers to the surface of a porous body that is closest to the heating element or to which the heating element is provided.

[0030] As used herein in relation to the present invention, the term "liquid-absorbing surface" refers to the surface of a porous material facing the heating surface. When in use, the liquid-absorbing surface may be arranged to receive the liquid aerosol-forming substrate from the liquid storage portion of the liquid aerosol-forming substrate storage section.

[0031] The average pore size of a porous material can vary in any way between the liquid-absorbing surface and the heated surface. The average pore size can range from relatively large pores at the liquid-absorbing surface to relatively small pores at the heated surface.

[0032] The porous material may include an average pore size gradient between the liquid-absorbing surface and the heating surface. The average pore size gradient may be constant, or it may be a variable average pore size gradient.

[0033] The average pore size can vary stepwise between the liquid-absorbing surface and the heated surface. For example, a portion of the porous material including the liquid-absorbing surface may have a first average pore size, while a portion of the porous material including the heated surface may have a second average pore size. The first average pore size may be larger than the second average pore size.

[0034] The porous body may have a heating end and a liquid absorption end, with the heating surface located at the heating end and the liquid absorption surface located at the liquid absorption end. The porous body may have a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end, with the first average pore diameter being larger than the second average pore diameter.

[0035] Providing a porous body having a large average pore diameter at the liquid absorption end and a smaller average pore diameter at the heating end can particularly facilitate the efficient movement of a liquid aerosol-forming substrate from the liquid absorption end to the heating end of the porous body without causing leakage. In particular, the inventors of the present invention have identified that the liquid aerosol-forming substrate moves from the liquid absorption end to the heating end of the porous body by capillary action. How quickly the liquid aerosol-forming substrate moves through the porous body depends on many factors, including but not limited to the pore shape, 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 aerosol-forming substrate, and the overall shape of the porous body. The inventors of the present invention have identified the need to balance these factors while preventing leakage of the liquid aerosol-forming substrate and providing efficient movement of the liquid aerosol-forming substrate to the heating surface of the porous body.

[0036] Firstly, to provide efficient capillary flow of liquid through a porous material, the capillary pressure must exceed the viscous drag pressure. Secondly, to prevent leakage, the inertial force must not exceed the capillary pressure. These two requirements are met by providing a porous material having larger pores at the liquid absorption end and smaller pores at the heating end.

[0037] In particular, the inventors of the present invention recognized that the viscosity of the liquid aerosol-forming substrate changes with temperature. Specifically, the viscosity of the liquid aerosol-forming substrate decreases as its temperature increases. As a result, the viscosity of the liquid aerosol-forming substrate decreases as it moves from the liquid absorption surface to the heated surface through the porous material. Since the liquid aerosol-forming substrate is transported through the porous material by capillary force, the capillary force must overcome the viscous drag of the liquid. Viscous drag decreases as viscosity decreases. As a result, the capillary force required to move the liquid aerosol-forming substrate decreases toward the heated surface of the porous material, while still maintaining the same flow rate. Consequently, the average pore size of the porous material can be reduced toward the heated surface without reducing the flow of the liquid aerosol-forming substrate through the porous material.

[0038] The porous material may contain pores having any pore size. The first average pore size may be at least 1 micrometer. For example, the first average pore size may be at least 2 micrometers, at least 5 micrometers, at least 10 micrometers, at least 25 micrometers, or at least 50 micrometers.

[0039] The first average pore diameter may be 250 micrometers or less. For example, the first average pore diameter may be 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, or 50 micrometers or less.

[0040] The first average pore diameter may be 1 micrometer to 250 micrometers. For example, the first average pore diameter may be 2 micrometers to 200 micrometers, 5 micrometers to 150 micrometers, 10 micrometers to 100 micrometers, or 25 micrometers to 50 micrometers.

[0041] The first average pore diameter may be 5 micrometers to 200 micrometers. The first average pore diameter may be 10 micrometers to 90 micrometers.

[0042] The second average pore diameter may be at least 1 micrometer. For example, the second average pore diameter may be at least 2 micrometers, at least 5 micrometers, at least 10 micrometers, at least 25 micrometers, or at least 50 micrometers.

[0043] The second average pore diameter may be 250 micrometers or less. For example, the second average pore diameter may be 200 micrometers or less, 150 micrometers or less, 100 micrometers or less, or 50 micrometers or less.

[0044] The second average pore size may be 1 micrometer to 250 micrometers. For example, the second average pore size may be 2 micrometers to 200 micrometers, 5 micrometers to 150 micrometers, 10 micrometers to 100 micrometers, or 25 micrometers to 50 micrometers.

[0045] The second average pore size may be 5 micrometers to 200 micrometers. The second average pore size may be 10 micrometers to 90 micrometers.

[0046] The first average pore diameter at the liquid absorption end of the porous material may be larger than the second average pore diameter at the heating end of the porous material.

[0047] The porous body may include a first porous material at the liquid absorption end and a second porous material at the heating end, wherein the first porous material has a first average pore diameter and the second porous material has a second average pore diameter.

[0048] In this way, the porous body may contain two adjacent porous materials, the two adjacent porous materials having different pore sizes.

[0049] The average pore size of the second porous material may be smaller than the average pore size of the first porous material.

[0050] The first porous material may contain the same material as the second porous material, except that the first porous material and the second porous material have different porosities. For example, the first and second porous materials may contain silicon nitride.

[0051] 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.

[0052] The length of the first porous material may be greater than the length of the second porous material.

[0053] As used herein in relation to the present invention, the term "length" refers to the dimensions of a component of a heater assembly measured along the longitudinal axis of the heater assembly.

[0054] As used herein in relation to the present invention, the term “longitudinal axis” refers to an axis extending between the liquid-absorbing surface and the heating surface of the porous body of the heater assembly. During use of the heater assembly, the liquid aerosol-forming substrate is drawn substantially along the long axis from the liquid-absorbing surface of the porous body to the heating surface of the porous body.

[0055] As used herein in relation to the present invention, the term "transverse direction" is used to describe a direction perpendicular to the longitudinal axis.

[0056] As used herein in relation to the present invention, the term "width" means the maximum dimension of a heater assembly, a component of a heater assembly, or a part of a heater assembly in the transverse direction.

[0057] The ratio of the length of the first porous material to the length of the second porous material may be at least 1. For example, 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.

[0058] The heating surface area of ​​the porous material may be substantially the same as the area of ​​the heating element.

[0059] In this way, the heating element can advantageously heat the entire heating surface of the porous body. This is advantageous because it can maximize the aerosolization of the liquid aerosol-forming substrate and prevent or reduce leakage of the liquid aerosol-forming substrate from the heating surface of the porous body.

[0060] The heating element may be any type of heating element. The heating element may be fluid permeable.

[0061] As used herein in relation to the present invention, the term "fluid permeability" in the context of a heating element means that a liquid aerosol-forming substrate can pass from one side of the heating element to the other side without wrapping around the heating element.

[0062] Naturally, if the heating element is fluid-permeable, the material from which the heating element is made may also be fluid-permeable. Alternatively, the material from which the heating element is made may be fluid-impermeable, but the structure or arrangement of the heating element may allow the liquid aerosol-forming substrate to pass from one side of the heating element to the other side.

[0063] The heating element may be an electrically heated element. For example, the heating element may be a resistance heating element. The heating element may have any preferred shape or form. Examples of preferred shapes and forms, but are not limited to, include strips, flakes, filaments, wires, meshes, flat spiral coils, fibers, or cloths.

[0064] In some preferred examples, the heating element is planar. A planar heating element may extend substantially within a plane.

[0065] In some preferred examples, the heating element comprises a mesh. The heating element may comprise an array of filaments forming a mesh. As used herein, the term “mesh” encompasses grids and arrays of filaments with spaces between them. The term mesh also includes woven and nonwoven fabrics.

[0066] The filaments may be formed by etching a sheet material such as foil. This can be particularly advantageous when the heater assembly comprises an array of parallel filaments.

[0067] If the heating element comprises a mesh or fabric of filaments, the filaments may be formed individually or knitted together.

[0068] The heating element may include an electrically resistant heating element. The heating element may be made from any suitable conductive material. Suitable materials include, but are not limited to, semiconductors such as doped ceramics, conductive ceramics (e.g., molybdenum disilide), carbon, graphite, metals, alloys, and composite materials made of ceramic and metallic materials. Such composite materials may include doped or undoped ceramics. A suitable example of a doped ceramic is doped silicon carbide. Suitable examples of metals include titanium, zirconium, tantalum, and platinum group metals. Suitable alloys include stainless steel, constantan, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, iron-aluminum alloys, and iron-manganese-aluminum alloys. Timetal® is a registered trademark of Titanium Metals Corporation. The heating element may be made from stainless steel, such as 300 series stainless steels, including AISI 304, 316, 304L, and 316L. In a preferred example, the electric heating element may comprise one or more of NiCr and TiZr.

[0069] Additionally, the heating element may comprise the above-mentioned combination of materials. Combinations of materials may be used to improve the control of the heating element's resistance. For example, a material with high resistivity may be combined with a material with low resistivity. This may be advantageous if one of the materials is more beneficial in terms of other respects, such as price, machinability, or other physical and chemical parameters. Advantageously, heating at high resistance allows for more efficient use of battery energy.

[0070] The electric heating element may be formed from a conductive material deposited on a porous body. As used herein, the term "conductive material" refers to a material having a resistivity of 1 x 10⁻² Ωm or less. As used herein, the term "deposited" means applied as a layer or coating by a physical or chemical process, for example, in the form of a liquid, plasma, or vapor, in which case the layer or coating does not simply lay on or fix to the porous body as a pre-formed solid component, but subsequently condenses or aggregates to form the electric heating element. In this way, the heating element is formed integrally with the porous body.

[0071] The electric heating element may be deposited directly onto the porous outer surface. In other words, the conductive material forming the electric heating element is deposited on the porous material such that the electric heating element is in direct contact with the porous material.

[0072] In some examples, the conductive material of the electric heating element may be diffused at least partially into the porous body. As used herein, the term “diffused into the porous body” means that the conductive material is incorporated into the porous material by extending, for example, into the pores of the porous body at the interface between the conductive material and the porous body. This arrangement may further improve the heating of the liquid aerosol-forming substrate and aerosol delivery by fixing the electric heating element to the porous body and increasing contact between the electric heating element and the porous body. In this way, the heating element is formed integrally with the porous body.

[0073] The conductive material forming the electric heating element may be deposited onto the porous body in any suitable manner. For example, the conductive material may be deposited onto the porous body using a dispensing pipette or syringe, or using a micro-tip transfer device such as a needle.

[0074] In some examples, at least one heating element comprises a printable conductive material printed on a porous body. In such embodiments, any suitable and well-known printing technique may be used, for example, one or more of screen printing, gravure printing, flexographic printing, and inkjet printing. Such printing processes may be particularly applicable to high-speed manufacturing processes.

[0075] Alternatively, the conductive material forming the electric heating element may be deposited onto the porous body by one or more vacuum deposition processes, such as vapor deposition and sputtering.

[0076] At least one heating element may be formed from any suitable conductive material. In certain preferred embodiments, the conductive material comprises one or more metals, conductive polymers, and conductive ceramics.

[0077] Suitable conductive metals include, but are not limited to, aluminum, silver, nickel, gold, platinum, copper, tungsten, and alloys thereof. In some embodiments, the conductive material comprises metal powder suspended in an adhesive such as epoxy resin. In one embodiment, the conductive material comprises silver-adhered epoxy.

[0078] Suitable conductive polymers include PEDOT (poly(3,4-ethylenedioxythiophene)), PSS (poly(p-phenylene sulfide)), PEDOT:PSS (a mixture of PEDOT and PSS), PANI (polyaniline), PPY (poly(pyrrole)), PPV (poly(p-phenylene vinylene)), or combinations thereof.

[0079] Suitable conductive ceramics include ITO (indium tin oxide), SLT (lanthanum-doped strontium titanate), SYT (yttrium-doped strontium titanate), or combinations thereof.

[0080] The conductive material may further comprise one or more additives selected from the group consisting of solvents, curing agents, adhesion promoters, surfactants, viscosity reducers, and aggregation inhibitors. Such additives may be used, for example, to assist in the deposition of the conductive material onto the porous outer surface of a porous body, to increase the amount of the conductive material that diffuses into the porous outer surface of a porous body, to shorten the time until the conductive material hardens, to increase the degree of adhesion between the conductive material and the porous body, or to reduce the amount of agglomeration of suspended particles, such as metal particles or powders, within the conductive material before the conductive material is applied to the porous outer surface of a porous body.

[0081] The heating element can have any length. As mentioned above, the “length” of the heating element may refer to the extension of the heating element measured along the long axis between the liquid-absorbing 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 called the “thickness” of the heating element.

[0082] The heating element may have a thickness of at least 1 micrometer. The heating element may have a thickness of at least 2 micrometers. The heating element may have a thickness of at least 5 micrometers. The heating element may have a thickness of at least 200 micrometers. The heating element may have a thickness of at least 220 micrometers.

[0083] The heating element may have a thickness of at least 300 micrometers. The heating element may have a thickness of at least 250 micrometers. The heating element may have a thickness of at least 50 micrometers. The heating element may have a thickness of at least 20 micrometers.

[0084] The heating element may have a thickness of 1 mm to 10 mm. The heating element may have a thickness of 1 mm to 5 mm. The heating element may have a thickness of 2 mm to 5 mm.

[0085] The heating element may have a thickness of 200 to 300 micrometers. The heating element may have a thickness of 200 to 250 micrometers. The heating element may have a thickness of 220 to 300 micrometers.

[0086] The heater assembly may further include first and second electrical contacts connected to a heating element. Each electrical contact may be located on the opposite side 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 between the electrical contacts.

[0087] Electrical contacts may be formed from any suitable material. Examples of suitable materials for electrical contacts include, but are not limited to, copper, zinc, silver, and gold.

[0088] In one example, the first and second electrical contacts may be formed from a conductive material deposited directly onto the heated surface of a porous body.

[0089] The electric heating element may extend in a wavy or meandering manner between electrical contacts. This helps to increase the length of the heating element between electrical contacts in contact with the porous outer surface, thereby helping to improve the heating of the liquid aerosol-forming substrate.

[0090] The porous body may contain any material. The porous body may comprise any porous material. The porous body may comprise a heat-resistant material.

[0091] The porous material may include at least one of oxide ceramic materials, non-oxide ceramic materials, glass ceramic materials, semiconductor materials, glass materials, and polymer materials.

[0092] The porous material may contain at least one of the following: alumina, aluminosilicate, zirconia, silicon carbide, silicon nitride, lithium aluminosilicate glass ceramic, silicide material, and boride material.

[0093] The porous body may include inert ceramics or biocompatible ceramics. Examples of suitable ceramics include those comprising aluminum oxide, zirconium oxide, silicon oxide, calcium silicate, and calcium phosphate containing hydroxyapatite. The porous body may also comprise ceramics containing one or more of Al2O3, ZrO2, SiO2, and Ca2SiO3. In a preferred example, the porous body comprises a ceramic containing either or both of SiO2 and Ca2SiO3. The advantage of using ceramic materials is that the heater assembly is thermally stable at the typical operating temperature, generally having a significantly higher thermal decomposition temperature than conventional wicks. This may help reduce the risk of unwanted byproducts being generated during dry heating.

[0094] The porous body may comprise a capillary material that transports a liquid aerosol-forming substrate through the material by capillary action. The porous body may have a fibrous structure or a porous structure. The porous body may comprise a bundle of capillaries. For example, the porous body may comprise a plurality of fibers or threads or other microtubules. The porous body may comprise fibers or threads made of cotton or treated cotton, such as acetylated cotton. Other suitable materials can also be used, for example, ceramic or graphite-based fibrous materials, or materials made from spun, drawn, or extruded fibers such as fiberglass, cellulose acetate, or any suitable heat-resistant polymer.

[0095] The porous body may comprise a plurality of interconnected open cellular pores. The porous body may comprise a capillary material that transports liquid through the material by capillary action. The porous body may have a fibrous structure or a porous structure. The porous body may comprise a bundle of capillaries. For example, the porous body may comprise a plurality of fibers or threads or other microtubules. The porous body may comprise fibers or threads made of cotton or treated cotton, such as acetylated cotton. Other suitable materials can also be used, for example, ceramic or graphite-based fibrous materials, or materials made from spun, drawn, or extruded fibers such as fiberglass, cellulose acetate, or any suitable heat-resistant polymer.

[0096] The specific pore size in the porous body of the present invention can be fabricated using any suitable method. For example, the pores in the porous body can be fabricated using etching techniques on the monolithic portion of the material. Alternatively, the pore size can be fabricated using a controlled sintering process, a sol-gel process, or a phase separation process. These processes enable the provision of pores in the porous body, which in turn enables the transfer of the liquid aerosol-forming substrate from the liquid-absorbing surface to the heated surface.

[0097] The porous material may be substantially incompressible.

[0098] The pores of a porous material may have any shape. The pores of a porous material may be interconnected. A porous material may contain a plurality of axially oriented pores extending from the liquid-absorbing surface of the porous material to the heating surface of the porous material.

[0099] When a porous material contains multiple pores in the longitudinal direction, the pore diameter can be defined as the width of the pore in the longitudinal direction when measured in the transverse direction.

[0100] As used herein in relation to the present invention, the term "transverse direction" refers to a direction perpendicular to the longitudinal axis.

[0101] Providing pores that extend along the long axis is advantageous in that it can facilitate the efficient movement of the liquid aerosol-forming substrate from the liquid-absorbing surface of the porous material to the heated surface of the porous material.

[0102] The porous material may have a surface extending along its long axis between the liquid-absorbing surface and the heating surface. The surface extending along its long axis may be impermeable to liquid.

[0103] Providing a liquid-impermeable surface along the long axis is advantageous in that it can prevent the liquid aerosol-forming substrate from leaking out from the surface along the long axis of the porous material.

[0104] The porous body may have a liquid-impermeable coating provided on the surface of the porous body in the longitudinal direction. Alternatively, the porous body may have pores extending in the longitudinal direction that prevent the liquid aerosol-forming substrate from reaching the surface of the porous body in the longitudinal direction. Alternatively, the pore diameter of the porous body on the surface in the longitudinal direction may be small enough to prevent the liquid aerosol-forming substrate from reaching the surface of the porous body in the longitudinal direction. Alternatively, the porous body may be enclosed in a liquid-impermeable housing, such as a glass tube, to prevent leakage of the liquid aerosol-forming substrate.

[0105] The porous body may have longitudinal grooves extending along the longitudinal surface of the porous body between the liquid-absorbing surface and the heating surface.

[0106] The longitudinal grooves may extend all the way from the liquid-absorbing surface of the porous material to the heating surface of the porous material. Providing longitudinal grooves can allow air to pass from the liquid-absorbing surface of the porous material to the heating surface of the porous material. During use, the longitudinal grooves are advantageous in that they can direct and guide air toward the heating surface of the porous material when the user inhales the aerosol generating system. As the air passes through the heating surface, it may mix with the aerosol generated by the heating element before being delivered to the user.

[0107] A porous body may have two or more grooves in the longitudinal direction. For example, a porous body may have at least two, at least three, at least four, or at least five grooves in the longitudinal direction. If a porous body has multiple grooves in the longitudinal direction, the grooves in the longitudinal direction may be evenly distributed around the periphery of the porous body.

[0108] The porous material may have a substantially constant cross-section. For example, the cross-sectional area of ​​the liquid-absorbing surface of the porous material may be substantially the same as the cross-sectional area of ​​the heating surface.

[0109] Porous materials can have any shape. For example, a porous material may generally be cylindrical. In this case, both the liquid absorption surface and the heating surface may be circular. A porous material may have a regular cubic shape. In this case, both the liquid absorption surface and the heating surface may be square.

[0110] The liquid-absorbing surface of the porous material may have a different area than the heating surface of the porous material. The heating surface area of ​​the porous material may be smaller than the liquid-absorbing surface area of ​​the porous material.

[0111] The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.9 or less.

[0112] The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.1.

[0113] The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be between 0.1 and 0.9.

[0114] The area of ​​the liquid-absorbing surface of the porous material may be smaller than the area of ​​the heating surface of the porous material.

[0115] The ratio of the liquid-absorbing surface area of ​​the porous material to the heating surface area of ​​the porous material may be 0.9 or less.

[0116] The ratio of the liquid-absorbing surface area of ​​the porous material to the heating surface area of ​​the porous material may be at least 0.1.

[0117] The ratio of the liquid-absorbing surface area of ​​the porous material to the heating surface area of ​​the porous material may be between 0.1 and 0.9.

[0118] A heater assembly having a heating surface with the same area as the liquid absorption surface may be inefficient because the heat generated by the heater is not used to vaporize the aerosol-forming substrate. Inefficient heater assemblies reduce aerosol throughput.

[0119] Advantageously, providing a porous material with different areas for the heating surface and the liquid absorption surface can improve the throughput of aerosols that may be generated by the heater assembly compared to a heater assembly where the heating surface has the same area as the liquid absorption surface.

[0120] For example, in a heater assembly where the area of ​​the heating surface of the porous material is smaller than the area of ​​the liquid-absorbing surface of the porous material, the heat flow conducted from the heating element to the liquid-absorbing surface and then to the liquid storage area can be reduced. The relatively small heating surface provides a small heat transfer region through conduction, which transfers heat from the heating element to the porous material and then to the liquid-absorbing surface.

[0121] Since much of the thermal energy provided by the heating element can be used to vaporize the aerosol-forming substrate, reducing heat loss from the heating element to the porous bulk can consequently increase heating efficiency. As a result, porous materials with a shape in which the heating surface has a smaller area than the liquid-absorbing surface can increase the aerosol throughput generated by the heater assembly.

[0122] For example, in a heater assembly where the area of ​​the porous liquid-absorbing surface is smaller than the area of ​​the porous heating surface, the smaller the area of ​​the liquid-absorbing surface, the less heat can flow from the heating element to the liquid-absorbing surface through the aerosol-forming substrate via heat conduction.

[0123] Since much of the thermal energy provided by the heating element can be used to vaporize the liquid aerosol-forming substrate, reducing the heat flow from the heated surface to the liquid-absorbing surface can consequently increase heating efficiency. As a result, porous bodies having a shape in which the liquid-absorbing surface has a smaller area than the heated surface may offer improved heating efficiency, which can increase the throughput of aerosols generated by the heater assembly.

[0124] Increased heating efficiency may reduce power consumption during use of the heater assembly.

[0125] The area of ​​the heated surface of the porous material may be smaller than the area of ​​the liquid-absorbing surface of the porous material. The area of ​​the liquid-absorbing surface of the porous material may be larger than the area of ​​the heated surface of the porous material.

[0126] Advantageously, if the porous material has a shape such that the heated surface has a smaller area than the liquid-absorbing surface, the heat flow conducted from the heating element to the liquid-absorbing surface and then to the liquid storage portion can be reduced. The relatively small heated surface provides a small heat transfer region through conduction, transferring heat from the heating element to the porous material and then to the liquid-absorbing surface.

[0127] Since much of the thermal energy provided by the heating element can be used to vaporize the aerosol-forming substrate, reducing heat loss from the heating element to the porous bulk can consequently increase heating efficiency. As a result, porous materials with a shape in which the heating surface has a smaller area than the liquid-absorbing surface can increase the aerosol throughput generated by the heater assembly.

[0128] Advantageously, a porous body having a shape such that the heating surface has a smaller area than the liquid absorption surface can reduce the area of ​​the heating surface that is not sufficiently close to the heating element, thereby allowing the aerosol-forming substrate to be transported to the heating surface. In other words, the size and shape of the heating surface may more closely match the size and shape of the heating element. As a result, more liquid aerosol-forming substrate may be transported from the liquid absorption surface to the region of the heating surface closer to the heating element, thereby allowing more liquid aerosol-forming substrate to be vaporized at the heating surface. An increase in the vaporized liquid aerosol-forming substrate can increase the aerosol throughput generated by the heater assembly. Furthermore, this arrangement may allow for maximization of the power density at the heating surface, which also improves heating efficiency.

[0129] Advantageously, a liquid absorption surface having a larger surface area than the heating surface may allow the liquid absorption surface to receive a larger volume of liquid aerosol substrate from the liquid storage portion. Because the heating surface has a relatively small surface area, the flow rate of liquid aerosol-forming substrate to the heating element may be higher than that in a typical heater assembly as the liquid aerosol-forming substrate is transported through the porous material toward the heating surface. A higher flow rate of liquid aerosol-forming substrate in the heating element may increase the throughput of aerosols generated by the heater assembly.

[0130] The area of ​​the heated surface of the porous material may be larger than the area of ​​the liquid-absorbing surface of the porous material. The area of ​​the liquid-absorbing surface of the porous material may be smaller than the area of ​​the heated surface of the porous material.

[0131] Advantageously, if the porous material has a shape such that the liquid absorption surface has a smaller area than the heating surface, the smaller the area of ​​the liquid absorption surface, the less heat can flow from the heating element to the liquid absorption surface through the aerosol-forming substrate via heat conduction. Since much of the thermal energy provided by the heating element can be used to vaporize the liquid aerosol-forming substrate, reducing the heat flow from the heating surface to the liquid absorption surface can consequently increase thermal efficiency. As a result, porous materials with a shape such that the liquid absorption surface has a smaller area than the heating surface can have improved heating efficiency, which can increase the throughput of aerosols generated by the heater assembly.

[0132] Advantageously, a porous body having a shape such that the liquid absorption surface has a smaller area than the heating surface can reduce the area of ​​the heating surface that is not sufficiently close to the heating element, thereby allowing the aerosol-forming substrate to be transported to the heating surface. In other words, the size and shape of the heating surface may more closely match the size and shape of the heating element. As a result, more liquid aerosol-forming substrate may be transported from the liquid absorption surface to the region of the heating surface closer to the heating element, thereby allowing more liquid aerosol-forming substrate to be vaporized at the heating surface. An increase in the vaporized liquid aerosol-forming substrate can increase the throughput of aerosols generated by the heater assembly.

[0133] The porous body may have any cross-sectional shape. The porous body may have a rectangular or circular cross-sectional shape.

[0134] The heated surface of the porous material may have any shape. The heated surface of the porous material may be curved along one or both of the first and second transverse directions, the first transverse direction being perpendicular to the second transverse direction.

[0135] The heated surface of the porous ceramic body may be convex in one or both of the first and second transverse directions, the first transverse direction being perpendicular to the second transverse direction.

[0136] The inclusion of such porous ceramic materials can increase the surface area of ​​the heated surface without increasing the width of the heated surface. This can help improve the efficiency of the aerosol generation system in the vaporization of the liquid aerosol-forming substrate, while avoiding the need to redesign other components of the aerosol generation system to accommodate the porous ceramic material.

[0137] Providing a heating surface that is convex along one or both of the first and second transverse directions may help avoid or minimize recirculation of the airflow adjacent to the heater assembly. In particular, a convex heating surface may help avoid or minimize recirculation of the airflow adjacent to the central region of the heater assembly. This may reduce the level of turbulence in the airflow adjacent to the heater assembly. Reducing the level of turbulence in the airflow adjacent to the heater assembly may improve the entrainment of vapors of aerosol-forming substrates in the airflow. This may improve the quality of aerosols generated by the aerosol-generating system.

[0138] Improving the entrainment of vapor in the airflow through an aerosol generation system can prevent or reduce the condensation of vapor into large droplets of liquid aerosol-forming substrates. This can help avoid an unpleasant and undesirable user experience.

[0139] Improving the entrainment of vapor in the airflow passing through an aerosol generating system can help avoid or reduce condensation of vapor on the internal surfaces of the aerosol generating system. This can help avoid or minimize damage to the aerosol generating system and enable its optimal functioning.

[0140] The heated surface of the porous material may be convex in a single transverse direction.

[0141] The heated surface of the porous body may be convex in both the first transverse direction and the second transverse direction.

[0142] The heating surface of the porous material may be convex in one or both of the first and second transverse directions, based on the configuration of the heater assembly relative to one or more airflow paths in the aerosol generating system. The heater assembly may be configured to minimize the level of turbulence in the airflow adjacent to the heater assembly. For example, it may be advantageous for the heater assembly to be positioned within the aerosol generating system such that the air drawn into the aerosol generating system follows a curved path along at least a portion of the curved surface of the heater assembly.

[0143] The heating element may be convex in one or both of the first and second transverse directions.

[0144] The curvature of the heating element in the first transverse direction may be substantially the same as the curvature of the heated surface of the porous material 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 heated surface of the porous material in the second transverse direction. The curvature of the heating element in both the first and second transverse directions may be substantially the same as the curvature of the heated surface of the porous material in both the first and second transverse directions, respectively.

[0145] The heater assembly may further include an insulating layer having a lower thermal conductivity than the porous body, the insulating layer being positioned between and in contact with the porous body and the heating element, and configured to reduce heat transfer from the heating element to the porous body.

[0146] In this configuration, heat loss from the heating element to the porous ceramic body and the liquid within the porous ceramic body is reduced. This provides a more efficient heater assembly that allows the user to increase the usage and frequency of the device before the device power source, such as a battery, is depleted. The inventors estimated that in known devices, approximately one-third of the energy from the heating element is lost through conduction through the porous body and the liquid within the porous body. The remaining two-thirds are used to generate an aerosol by heating a liquid aerosol-forming substrate. In the configuration described herein, these energy losses are reduced. Specifically, the insulating layer reduces heat propagation or conduction from the heating element to or through the porous ceramic body. This reduction in conduction can concentrate heat on the heated surface of the porous ceramic body, minimizing heat dissipation and increasing the heating efficiency of the heater assembly. The insulating layer may include an insulating material. The insulating material may have a lower thermal conductivity than the porous ceramic body. The insulating material may have a higher porosity than the porous ceramic body. This has the advantage of being easy to manufacture while providing an insulating layer that is particularly effective in reducing energy loss.

[0147] The insulation layer may include a material having a thermal conductivity of less than 40 watts / meter Kelvin. This has the advantage of providing an insulation layer that is effective in reducing energy loss through the porous ceramic body. The insulation layer may also include a material having a thermal conductivity of less than 10 watts / meter Kelvin. This has the advantage of providing an insulation layer that is particularly effective in reducing energy loss through the porous ceramic body.

[0148] The insulating layer may extend throughout the space 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 is therefore particularly effective in reducing energy loss through the porous ceramic body.

[0149] The insulating layer may contain one or more of the following: alumina, zirconia, zirconia containing magnesium oxide, glass ceramic, quartz, and porous polymer. The porous polymer may be polyimide.

[0150] The insulation layer may contain alumina having a thermal conductivity of 20-40 watts / meter Kelvin. The insulation layer may also contain materials having a thermal conductivity of less than 10 watts / meter Kelvin, such as zirconia, glass ceramics, or quartz, with or without magnesium oxide. The use of alumina, zirconia, glass ceramics, or quartz, with or without magnesium oxide, is advantageous because these materials are compatible with manufacturing processes involving sintering, and therefore heater assemblies having an insulation layer made of one of these materials are easier to manufacture.

[0151] The insulation layer may have a thickness of 0.1 mm to 2 mm. An insulation layer having such a thickness is particularly suitable for reducing energy loss from the heating element to the porous ceramic body. Preferably, the insulation layer has a thickness of 0.5 mm to 1.5 mm. An insulation layer having such a thickness is even more suitable for reducing energy loss from the heating element to the porous ceramic body.

[0152] As used herein in relation to the present invention, the term “thermal insulation” refers to a property in which heat transfer is reduced or limited. A more thermally insulating component transfers less heat through conduction, convection, or radiation than a less thermally insulating component.

[0153] The heating element may comprise multiple tracks or track sections electrically arranged in parallel. The resistance of the heating element at room temperature may be 0.5 ohms to 1.5 ohms, preferably 0.7 ohms to 1.3 ohms, and more preferably 1 ohm. The resistance of the heating element can be tailored to the requirements of the control electronic equipment.

[0154] At least two of the electrically parallel heating tracks may have similar resistances or identical resistances. Preferably, all electrically parallel heating tracks have similar or identical resistances. Electrically arranged heating tracks in parallel may have different resistances, which is particularly beneficial in heater assemblies where zones of the heating element are advantageous for generating different power levels. This may be, for example, to compensate for higher heat loss in the outer portion of the heating element. Thus, heating tracks on the outside or on the outer portion of the heating element may be designed to have lower resistances (and thus generate more heat) than the heating track in the center of the heating element.

[0155] The heating element may have multiple tracks or track sections. The multiple tracks or track sections may be electrically arranged in parallel. By being electrically arranged in parallel, the current flow is divided into separate parallel channels, which are then recombined.

[0156] The heating element may include a first connection pad and a second connection pad. The first or second connection pad (or the first and second connection pads) may be configured to allow connection to an external circuit. Openings or multiple openings within the heating element may isolate each track or track portion. The heating element may include at least one branching portion where the current is divided from the first connection pad to the track portions. The track portions define electrically parallel paths. The heating element may also include a convergence portion. In the convergence portion, the current is coupled from the track portions defining electrically parallel paths to the second connection pad.

[0157] Various different arrangements of electrically arranged tracks or track sections are possible. The heating element may have two, three, four or more track sections that define electrically parallel paths.

[0158] By electrically arranging tracks or track sections in parallel, if one track section is faulty, the current can be redistributed and can still flow through the heating element, meaning the electrical connection between the first and second connecting pads is not broken. In contrast, in a simple meandering heater that defines a single electrical path between the first and second connecting pads, if a portion of the meandering heating element is damaged or faulty, this can cause an increase in local resistance, leading to increased power consumption and potentially increasing resistance until further damage occurs.

[0159] The inventors also identified that electrically parallel tracks or track sections have a surprising additional advantage. In such arrangements, if one track section fails, the heating element continues to operate and can operate in a favorable manner for an initial transient period, as the failure of one track or track section results in a higher energy density for the remaining tracks or track sections. In such cases, the same power is still provided, but over a smaller area, thus increasing the throughput of the aerosol generating substrate. Such failures, which cause an increase in current on the undamaged tracks or track sections, can ultimately affect the user experience. This can be mitigated by a mechanism to warn the user about the possibility that the performance of the heater assembly may fall below optimal levels in the future. Electrically parallel tracks have the advantage of increasing the number of fume extractions before the heater completely fails, potentially increasing the heater's lifespan to the end of the device's life.

[0160] The heating element may comprise multiple tracks or track sections defining a path having at least one bend, the inner end of the bend being curved.

[0161] The curved inner end of a bend has the advantage of guiding the current to flow more evenly around at least one bend. This reduces current concentration and limits the generation of hot spots.

[0162] The heating element may include multiple tracks or track sections having an electrical resistivity gradient perpendicular to the current flow at the corner, resulting in higher electrical resistivity on the inside of the corner and lower resistivity on the outside. Such gradients are beneficial for offsetting localized high current densities and reducing hotspot formation.

[0163] The heating element may comprise multiple tracks or track sections arranged at a distance between at least two of multiple tracks or track sections within a range of 150 to 300 micrometers.

[0164] All tracks or track sections may be spaced 200-300 micrometers apart from at least one other track section. This has the advantage of providing a particularly efficient heater assembly in which the aerosol-forming substrate is efficiently vaporized.

[0165] The heating element and the porous body may be molded as a single monolithic piece.

[0166] This can also help simplify the manufacturing of heater assemblies by reducing manufacturing time and providing a more cost-effective solution. This can, advantageously, create a tight mechanical connection between the heating element and the porous body.

[0167] The heating element may be a doped portion of a porous material.

[0168] Porous materials may be doped such that the portion of the porous material acting as a heat-generating element is conductive. Doping a porous material can be advantageous in that it avoids changes in the porosity of the porous material. This may be preferable to other known techniques for forming heat-generating elements, including depositing the heat-generating element by thin-film or thick-film techniques that can reduce the properties of the porous material, particularly its porosity. The doped portion may be 5 to 100 micrometers thick. The thickness of the doped portion may be increased if the cross-sectional area of ​​the heat-generating element is small or if the required heating resistance is high. The dopant used to dope the porous material may be an n-type dopant or a p-type dopant. The dopant may be, but is not limited to, nitrogen, phosphorus, aluminum, or boron. The interface between the heat-generating element and the porous material may include a portion of the partially doped porous material.

[0169] Porous materials may be doped by ion transplantation. Ion transplantation involves the transplantation or exchange of ions into a layer of bulk material, removing one species and replacing it with another. Ion transplantation can be carried out chemically or physically.

[0170] Porous materials may be doped by nuclear transmutation. Nuclear transmutation involves the irradiation of particles such as neutrons or alpha particles to convert one atomic species already present in a material into another, resulting in a short-lived decay process that leads to a stable isotope not present in the original material. Nuclear transmutation has the advantage that doping occurs directly within the ceramic material and does not require the bonding or attachment of additional conductive materials. Thus, nuclear transmutation offers a more monolithic approach.

[0171] Another embodiment of the present disclosure provides a cartridge for an aerosol generating system. The cartridge comprises a heater assembly according to the present invention. The cartridge further comprises a liquid storage portion configured to hold a liquid aerosol forming substrate. The liquid storage portion is disposed on a porous liquid-absorbing surface.

[0172] The liquid storage portion may also be known as the storage section. The liquid storage portion may contain a liquid aerosol-forming substrate.

[0173] The liquid aerosol-forming substrate may contain both liquid and solid components. The liquid aerosol-forming substrate may contain nicotine. A nicotine-containing liquid aerosol-forming substrate may be a nicotine salt matrix. The liquid aerosol-forming substrate may contain plant-derived materials. The liquid aerosol-forming substrate may contain tobacco. The liquid aerosol-forming substrate may contain tobacco-containing materials containing volatile tobacco-flavored compounds released from the aerosol-forming substrate upon heating. The liquid aerosol-forming substrate may contain homogenized tobacco materials. The liquid aerosol-forming substrate may contain non-tobacco-containing materials. The liquid aerosol-forming substrate may contain homogenized plant-derived materials.

[0174] A liquid aerosol-forming substrate may comprise one or more aerosol-forming elements. An aerosol-forming element is any suitable known compound, or mixture of compounds, that facilitates the formation of a high-density, stable aerosol during use and is substantially resistant to thermal decomposition at the system's operating temperature. Examples of suitable aerosol-forming elements include glycerin and propylene glycol. Suitable aerosol-forming elements are well known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (such as dimethyl dodecanediol and dimethyl tetradecanediol). A liquid aerosol-forming substrate may also contain water, solvents, ethanol, plant extracts, and natural or artificial flavors.

[0175] The liquid aerosol-forming substrate may contain nicotine and at least one aerosol-forming agent. The aerosol-forming agent may be glycerin or propylene glycol. The aerosol-forming agent may contain both glycerin and propylene glycol. The liquid aerosol-forming substrate may have a nicotine concentration of about 0.5% to about 10%, for example, about 2%.

[0176] The liquid storage portion may be located on the liquid-absorbing surface of the porous material. The airflow channel may be located on the heating surface of the porous material. The airflow channel may be adjacent to the heating element. The airflow path may extend through the heating element. The airflow path may be configured to transport aerosols. The cartridge body may be configured such that the airflow that has passed through the heater assembly entrains the vaporized aerosol-forming substrate.

[0177] The cartridge may have a mouthpiece located at the oral end of the cartridge. The mouthpiece may have an aerosol outlet through which the generated aerosol may be inhaled by the user. The cartridge may have a connection terminal configured to connect the cartridge to an aerosol generator.

[0178] The cartridge may have an air intake. The cartridge may have an enclosed airflow passage from the air intake to the aerosol outlet. The enclosed airflow passage may extend from the air intake through the heater assembly to the aerosol outlet. The enclosed airflow passage may pass around the outer surface of the liquid storage portion. Alternatively, the enclosed airflow passage may pass through the liquid storage portion. For example, 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.

[0179] The cartridge may include a first airflow path extending in a first direction from the air intake toward the heater assembly. The cartridge may include a second airflow path extending through the heating element and configured to entrain aerosols. The cartridge may include a third airflow path extending in a second direction from the heater assembly toward the aerosol outlet. The second direction may be opposite to the first direction. The second airflow path may provide a fluid connection between the first and third airflow paths.

[0180] The cartridge may include 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 from a moldable plastic material such as polypropylene (PP) or polyethylene terephthalate (PET), or from a copolymer such as Tritan® made from three monomers, namely 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 section. The cartridge housing and the liquid storage section may be formed integrally. Alternatively, the liquid storage section may be formed separately from the cartridge housing or disposed within the cartridge housing.

[0181] According to another embodiment of the present disclosure, an aerosol generating system comprising a cartridge according to the present invention is provided.

[0182] The system may further include an aerosol generator comprising a power supply for supplying power to a heater assembly and a control circuit for controlling the supply of power from the power supply to the heater assembly. The cartridge is detachably coupled to the aerosol generator.

[0183] The aerosol generating system may further include an air intake and an aerosol outlet, the air intake being in fluid communication with the aerosol outlet to define an airflow path through the aerosol generating system.

[0184] The heater assembly may be arranged in fluid communication with an airflow path such that air flows through the heater assembly in the mean airflow direction, and the heater assembly and airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0185] According to embodiments of the present disclosure, an aerosol generating system is provided comprising a heater assembly, an air intake, and an aerosol outlet, wherein the air intake is in fluid communication with the aerosol outlet to define an airflow path through the aerosol generating system, the heater assembly is arranged in fluid communication with the airflow path such that air flows through the heater assembly in the mean airflow direction, and the heater assembly and the airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees. The features described herein with respect to a heater assembly according to a first aspect of the present invention are equally applicable to a heater assembly of an aerosol generating system.

[0186] The aerosol generating system may also include a heater assembly comprising a heating element for vaporizing a liquid aerosol forming substrate and a porous body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous body has a liquid absorption surface and a heating surface, the heating element is located on the heating surface of the porous body, the heating element and the porous body are integrally formed, and the average pore diameter of the porous body changes between the liquid absorption surface and the heating surface. The aerosol generating system further comprises an air intake and an aerosol outlet, the air intake being in fluid communication with the aerosol outlet to define an airflow path through the aerosol generating system, the heater assembly being arranged in fluid communication with the airflow path so that air flows through the heater assembly in the mean airflow direction, and the heater assembly and the airflow path being arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0187] As used herein in relation to the present invention, the term “angle between mean vapor discharge direction and mean airflow direction” refers to the angle between the direction of movement of vapor discharged from the heater assembly and the airflow within the airflow path. For example, an angle of zero degrees means that the airflow and vapor discharge are moving in the same direction, while an angle of 180 degrees means that the directions of movement of the airflow and vapor discharge are directly opposite each other.

[0188] Advantageously, by arranging the heater assembly and airflow path so that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees, the mean airflow direction does not directly oppose the mean vapor discharge direction. Therefore, the momentum of the vapor and airflow is not reduced as much as when the mean airflow direction directly opposes the mean vapor discharge direction. This reduces the tendency for recirculation and turbulence to occur within the airflow path and makes it less likely for vapor to collide with the internal surfaces of the aerosol generation system. Consequently, the likelihood of aerosol condensation occurring within the aerosol generation system is reduced.

[0189] The average vapor emission direction may be substantially perpendicular to the heated surface. As used herein, the term “substantially perpendicular” means 90 degrees plus or minus 10 degrees, preferably plus or minus 5 degrees.

[0190] The advantage of the mean vapor release direction being substantially perpendicular to the heated surface is that, since the vapor is released substantially perpendicular to the heated surface of the porous material, it becomes easier to orient the mean vapor release direction relative to the mean airflow direction. Therefore, by appropriately angling the heater assembly with respect to the airflow in the airflow path, or vice versa, the desired angle between the mean vapor release direction and the mean airflow direction can be achieved.

[0191] The heater assembly and airflow path may be arranged such that the angle between the average vapor discharge direction and the average airflow direction is less than 110 degrees, preferably less than 100 degrees.

[0192] The heater assembly and airflow path may be arranged such that the angle between the mean vapor release direction and the mean airflow direction is approximately 90 degrees. This arrangement causes the vapor to be released at an angle substantially perpendicular to the mean airflow direction. The mean vapor release direction has no velocity or directional component opposite to the airflow direction, and therefore the loss of momentum in the airflow is reduced. This reduces the tendency for recirculation and turbulence to occur within the airflow path and makes it less likely for vapor to collide with the internal surfaces of the aerosol generating system. Furthermore, the entrainment of vapor into the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is reduced.

[0193] The heater assembly and airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 90 degrees. In this arrangement, the mean vapor discharge direction does not have a velocity or directional component opposite to the airflow direction, and in fact has a velocity and directional component in the same direction as the mean airflow direction. Thus, momentum loss of the airflow is further reduced. This reduces the tendency for recirculation and turbulence to occur within the airflow path and makes it less likely for vapor to collide with the internal surfaces of the aerosol generation system. Furthermore, vapor entrainment into the airflow is improved. Thus, the likelihood of aerosol condensation occurring within the aerosol generation system is reduced.

[0194] The heater assembly and airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is approximately 45 degrees. The heater assembly and airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 45 degrees.

[0195] The heater assemblies and airflow paths may be arranged such that the mean vapor discharge direction and the mean airflow direction are substantially the same. In this arrangement, since the mean vapor discharge direction and the mean airflow direction are the same, there is virtually no loss of momentum in the airflow. This reduces the tendency for recirculation and turbulence to occur within the airflow path and reduces the likelihood of vapor colliding with the internal surfaces of the aerosol generating system. Furthermore, vapor entrainment into the airflow is improved. Consequently, the likelihood of aerosol condensation occurring within the aerosol generating system is reduced.

[0196] The cross-sectional area of ​​the airflow path in the heater assembly region may be configured such that the airflow velocity during use is 0.1 to 2 meters / second, preferably 0.5 to 1.5 meters / second, and more preferably about 1 meter / second. It has been found that airflow velocities in this range effectively entrain steam released from different designs of the heating element without excessively cooling the heating element.

[0197] The aerosol generator may include a housing. The housing may be elongated. The housing may contain any suitable material or a combination of such materials. Examples of suitable materials include metals, alloys, plastics, or composite materials containing one or more of these materials, or thermoplastic resins suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. The material is preferably lightweight and non-brittle.

[0198] The housing of the aerosol generator may define a recess or indentation for receiving a portion of the cartridge. The aerosol generator may have a connecting end configured to detachably connect the aerosol generator to the cartridge. The connecting end may have a recess or indentation for receiving the cartridge.

[0199] The aerosol generator may have a distal end opposite to the connection end. The distal end may include an electrical connector configured to connect the aerosol generator to an electrical connector of an external power supply in order to charge the power supply of the aerosol generator.

[0200] The aerosol generating system may include an air intake. The air intake may be located at the boundary between the cartridge and the aerosol generator. The aerosol generating system may include an enclosed airflow passage from the air intake to the aerosol outlet. The enclosed airflow passage may extend from the air intake, through the heater assembly, to the aerosol outlet.

[0201] The aerosol generating system may include a first airflow path extending in a first direction from an air intake towards a heater assembly. The aerosol generating system may also include a second airflow path extending through an electric heating element and configured to entrain aerosols. The aerosol generating system may also include a third airflow path extending in a second direction from the heater assembly towards an aerosol outlet. The second direction may be opposite to the first direction. The second airflow path may provide a fluid connection between the first and third airflow paths.

[0202] The power source may be any suitable power source. Preferably, the power source is a DC power source. The power source may be a battery. The battery may be a lithium-based battery, for example, a lithium cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a lithium polymer battery. The battery may be a nickel-metal hydride battery or a nickel-cadmium battery. The power source may be another form of charge storage device, such as a capacitor. The power source may be rechargeable and may be configured to undergo multiple charge-discharge cycles. The power source may have a capacity that allows for the storage of sufficient energy for one or more user experiences of the aerosol generating system. For example, the power source may have a capacity that allows for continuous aerosol generation for about six minutes, or a multiple of six minutes, corresponding to the typical time it takes to smoke one conventional cigarette. In another embodiment, the power source may have a capacity that allows for a predetermined number of smoking sessions or for intermittent startup of the aerosol generating system.

[0203] The control circuit may include any suitable controller or electrical component. The controller may include memory. Information for carrying out the above-described method may be stored in memory. The control circuit may include a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, an application-specific integrated circuit (ASIC), or other electronic circuit capable of providing control. The control circuit may be configured to supply power to the heating element continuously after the device is started up, or to supply power intermittently, such as with each smoke extraction. Power may be supplied to the heating element in the form of current pulses, for example by pulse-width modulation (PWM).

[0204] The control circuit may include further electronic components. For example, in some embodiments, the control circuit may include a sensor, a switch, or a display element.

[0205] The aerosol generating system may include a smoke extraction detector. The smoke extraction detector may be configured to detect when a user has inhaled the aerosol generating system. The smoke extraction detector may be any suitable sensor capable of detecting when a user is inhaling the aerosol generating device. For example, the smoke extraction detector may be an airflow sensor. The control circuit may be configured to supply power to the heating element when the smoke extraction detector detects a user inhaling the aerosol generating system.

[0206] Features described in relation to one of the above embodiments may be equally applicable to other embodiments of the present disclosure.

[0207] The present invention is defined in the claims. However, a non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of other embodiments, forms, or aspects described herein.

[0208] Example 1. A heater assembly for an aerosol generation system, comprising: a heating element for vaporizing a liquid aerosol forming substrate; and a porous body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous body has a liquid absorption surface and a heating surface, the heating element is located on the heating surface of the porous body, the heating element and the porous body are integrally formed, and the average pore diameter of the porous body changes between the liquid absorption surface and the heating surface. Example 2. The porous body has a heating end and a liquid absorption end, with the heating surface located at the heating end and the liquid absorption surface located at the liquid absorption end. The heater assembly according to Example 1, wherein the porous body has a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end, and the first average pore diameter is larger than the second average pore diameter. Example 3. The heater assembly described in Example 2, wherein the first average pore size is 5 micrometers to 200 micrometers. Example 4. The heater assembly according to Example 2 or 3, 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 a first average pore diameter and the second porous material having a second average pore diameter. Example 5. The heater assembly according to Example 4, wherein the length of the first porous material is greater than the length of the second porous material. Example 6. The heater assembly according to Example 5, wherein the ratio of the length of the first porous material to the length of the second porous material is at least 2. Example 7. A heater assembly according to any one of Examples 1 to 6, wherein the heating surface area of ​​the porous material is substantially the same as the area of ​​the heating element. Example 8. A heater assembly according to any of Examples 1 to 7, wherein the heating element is fluid permeable. Example 9. A heater assembly according to any one of Examples 1 to 8, wherein the porous body comprises at least one of oxide ceramic material, non-oxide ceramic material, glass ceramic material, semiconductor material, glass material, and polymer material. Example 10. A heater assembly according to any one of Examples 1 to 9, wherein the porous body comprises at least one of alumina, aluminosilicate, zirconia, silicon carbide, silicon nitride, lithium aluminosilicate glass ceramic, silicide material, and boride material. Example 11. A heater assembly according to any one of Examples 1 to 10, wherein the porous body has a plurality of axially oriented pores extending from the liquid-absorbing surface of the porous body to the heating surface of the porous body. Example 12. A heater assembly according to any one of Examples 1 to 11, wherein the porous body has a surface in the longitudinal direction that extends between the liquid absorption surface and the heating surface, and the surface in the longitudinal direction is impermeable to liquid. Example 13. The heater assembly according to Example 12, further comprising at least one longitudinal groove extending along the longitudinal surface of a porous body between the liquid absorption surface and the heating surface. Example 14. A heater assembly according to any one of Examples 1 to 13, wherein the liquid-absorbing surface of the porous material has a different area from the heating surface of the porous material. Example 15. A heater assembly according to any of Examples 1 to 14, wherein the heating surface area of ​​the porous material is smaller than the liquid-absorbing surface area of ​​the porous material. Example 16. A heater assembly according to any of Examples 1 to 15, wherein the ratio of the area of ​​the heating surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material is 0.9 or less. Example 17. A heater assembly according to any one of Examples 1 to 16, wherein the ratio of the area of ​​the heating surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material is at least 0.1. Example 18. A heater assembly according to any of Examples 1 to 17, wherein the ratio of the area of ​​the heating surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material is 0.1 to 0.9. Example 19. A heater assembly according to any of Examples 1 to 18, wherein the porous body has a rectangular or circular cross-sectional shape. Example 20. A heater assembly according to any of Examples 1 to 19, wherein the heating surface of the porous body is curved along one or both of the first transverse direction and the second transverse direction, and the first transverse direction is perpendicular to the second transverse direction. Example 21. A heater assembly according to any of Examples 1 to 20, wherein the heating surface is convex in one or both of the first transverse direction and the second transverse direction. Example 22. A heater assembly according to any one of Examples 1 to 21, further comprising an insulating layer having a lower thermal conductivity than the porous ceramic body, wherein the insulating layer is disposed between and in contact with the porous ceramic body and the heating element, and the insulating layer is configured to reduce heat transfer from the heating element to the porous ceramic body. Example 23. The heater assembly according to Example 22, wherein the insulation layer contains an insulating material, and the insulating material has lower thermal conductivity than the porous ceramic body. Example 24. The heater assembly according to Example 22 or 23, wherein the insulation layer comprises a material having a thermal conductivity of less than 40 watts / meter Kelvin. Example 25. A heater assembly according to any one of Examples 22 to 24, wherein the insulation layer comprises a material having a thermal conductivity of less than 10 watts / meter Kelvin. Example 26. A heater assembly according to any one of Examples 22 to 25, wherein the insulation layer contains an insulating material, and the insulating material has a higher porosity than a porous ceramic body. Example 27. A heater assembly according to any one of Examples 1 to 26, wherein the heating element includes a track that defines a path across the heated surface of a porous ceramic body. Example 28. A heater assembly according to any one of Examples 1 to 27, wherein the heating element comprises a plurality of tracks or track portions arranged at a distance between at least two of a plurality of tracks or track portions within a range of 200 to 300 micrometers. Example 29. A heater assembly according to any of Examples 1 to 28, wherein the heating element comprises multiple tracks or track sections electrically arranged in parallel. Example 30. A heater assembly according to any one of Examples 1 to 29, wherein the heating element comprises a plurality of tracks or track portions defining a path having at least one bend, and the inner edge of the bend is curved. Example 31. A heater assembly according to any one of Examples 1 to 30, wherein the heating element and the porous body are molded as a single monolithic piece. Example 32. A heater assembly according to any of Examples 1 to 31, wherein the heating element is the doped portion of a porous material. Example 33. A cartridge for an aerosol generating system comprising a heater assembly described in any of Examples 1 to 32, and a liquid storage portion configured to hold a liquid aerosol forming substrate, wherein the liquid storage portion is disposed on a porous liquid-absorbing surface. Example 34. An aerosol generating system comprising a cartridge as described in Example 33, an aerosol generator having a power supply for supplying power to a heater assembly, and a control circuit for controlling the power supply from the power supply to the heater assembly, wherein the cartridge is detachably coupled to the aerosol generator. Example 35. The aerosol generating system according to Example 34, further comprising an air intake and an aerosol outlet, wherein the air intake is in fluid communication with the aerosol outlet to define an airflow path through the aerosol generating system, a heater assembly is arranged in fluid communication with the airflow path such that air flows through the heater assembly in the mean airflow direction, and the heater assembly and the airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0209] Here, we will further describe the examples with reference to the figures.

[0210] The heater assembly 100 shown in Figure 1 is used in an aerosol generation system. The heater assembly 100 comprises a heating element 120 for vaporizing a liquid aerosol-forming substrate and a porous body 110 for transporting 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.

[0211] In the embodiment shown in Figure 1, the porous body 110 is cylindrical and formed from sintered ceramic. The porous body 110 is formed from silicon carbide. The porous body 110 contains open pores. The open pores are axially oriented pores that generally extend from the liquid absorption surface 111 to the heated surface 112 of the porous body. The pore diameter of the pores in the porous body 110 varies between the liquid absorption surface 111 and the heated surface 112.

[0212] The porous body 110 includes a heating end and a liquid absorption end, with the heating surface 112 located at the heating end and the liquid absorption surface 111 located at the liquid absorption end. The porous body has a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end. The first average pore diameter is larger than the second average pore diameter.

[0213] The first pore diameter at the liquid absorption end is approximately 150 micrometers. The second pore diameter at the heating end is approximately 20 micrometers. The pore diameter changes linearly between the first and second pore diameters, providing a pore diameter gradient between the liquid absorption end and the heating end of the porous body 110.

[0214] The pore structure and pore diameter gradient of the porous body 110 are achieved by etching the pores with a portion of silicon carbide.

[0215] The heating element 120 is a resistance heating element comprising tracks arranged in a meandering manner on the heating surface 112 of the porous body 110. The meandering arrangement of the resistance heating element tracks allows fluid to pass between adjacent portions of the resistance heating element. The distance between adjacent parallel portions of the resistance heating element tracks is 250 micrometers. Thus, the resistance heating element may be described as fluid-impermeable. The resistance heating element includes a conductive material deposited on the heating surface 112 of the porous body 110. The conductive material includes stainless steel.

[0216] The porous body 110 further comprises a longitudinal surface 113 extending between the liquid-absorbing surface 111 and the heating surface 112. The longitudinal surface 113 includes a liquid-impermeable coating.

[0217] The heater assembly 200 shown in Figure 2 contains most of the same features as the heater assembly 100 shown in Figure 1, and the same reference numerals are used to refer to similar features. The heater assembly 200 shown in Figure 2 differs from the heater assembly 100 shown in Figure 1 because it contains a first porous material 121 and a second porous material 122. The first porous material 121 is located at the liquid absorption end of the porous body 110. The second porous material 122 is located 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. Thus, unlike the embodiment in Figure 1, the heater assembly 150 in Figure 2 does not include a stepped pore diameter gradient between the liquid absorption surface 111 and the heating surface. Instead, the heater assembly 200 in Figure 2 includes a stepped change in average pore diameter at the interface between the first porous material 121 and the second porous material 122. The average pore diameter of the first porous material 121 is approximately 150 micrometers. The average pore diameter of the second porous material 122 is approximately 20 micrometers.

[0218] The heater assembly 300 shown in Figure 3 contains most of the same features as the heater assembly 100 shown in Figure 1, and the same reference numerals are used to refer to similar features. The heater assembly 300 shown in Figure 3 differs from the heater assembly 100 shown in Figure 1 in that the heating surface 112 of the porous body 110 is curved in a convex direction along both the first and second transverse directions, with the first transverse direction being perpendicular to the second transverse direction. The heating surface 112 is curved in a convex direction.

[0219] The heater assembly 400 shown in Figures 4 and 5 contains most of the same features as the heater assembly 100 shown in Figure 1, and the same reference numerals are used to refer to the same features. Figure 4 shows a plan view of the heater assembly 400 viewed along the long axis toward the heating surface 112. Figure 5 shows a plan view of the heater assembly 400 viewed along the transverse direction. The heater assembly 400 shown in Figures 4 and 5 differs from the heater assembly 100 shown in Figure 1 because the area of ​​the liquid-absorbing surface 111 of the porous body 110 is larger than the area of ​​the heating surface 112 of the porous body 110. Both the liquid-absorbing surface 111 and the heating surface 112 are circular. In this way, the porous body 110 of the heater assembly 400 has a truncated cone shape.

[0220] The heater assembly 400 shown in Figures 4 and 5 is further different from the heater assembly 100 shown in Figure 1, because the heater element 120 is provided as a mesh of conductive material integrally formed with the porous body 110.

[0221] The heater assembly 500 shown in Figures 6 and 7 has almost the same features as the heater assembly 100 shown in Figure 1, and similar reference numbers are used to refer to the same features. Figure 6 shows a plan view of the heater assembly 500 viewed along the long axis toward the heating surface 112. Figure 6 shows a plan view of the heater assembly 500 viewed along the transverse direction. The heater assembly 500 shown in Figures 6 and 7 differs from the heater assembly 100 shown in Figure 1 because the area of ​​the liquid-absorbing surface 111 of the porous body 110 is larger than the heating surface 112 of the porous body 110. Both the liquid-absorbing surface 111 and the heating surface 112 are square. In this way, the porous body 110 of the heater assembly 500 has the shape of a square-based pyramidal pyramid. The surface 113 of the porous body 110 along the long axis is divided into four equally sized surfaces.

[0222] 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 surface 113 includes a longitudinal groove 510. Each of the longitudinal grooves 510 extends from the liquid absorption surface 111 to the heating surface 112. The longitudinal grooves 510 allow air entrained with aerosols generated on 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.

[0223] Figures 8 and 9 show schematic diagrams of the current flow 800 around the corner of the track of the heating element 120.

[0224] Figure 8 is a schematic diagram of the current flow 800 around a known heating element 120, where the track portion defines a path with a bend, and the inner edge of the bend has a sharp corner. In such a track, the current flow is concentrated (i.e., there is an increase in current density) indicated by the arrow 800 following the path of least resistance. This concentration occurs at the inner edge of the corner. Current concentration can increase the local temperature, which can lead to the formation of a hot spot at the corner. Hot spots are undesirable because they can affect the efficiency and reliability of the heating element. Hot spots occur despite the possibility that the local resistivity of the heater track material may increase due to the local increase in temperature (directing the current to flow through the path of lower resistance).

[0225] Figure 9 is a schematic diagram of the current flow 800 around the heating element 120 according to the present invention, where the track portion defines a path with bends, and the inner end of the bend is curved. In such a track, the current flow 800 does not form localized hot spots.

[0226] In contrast to the track shape shown in Figure 8, the current flow 800 in the smoother, curved track section shown in Figure 9 remains more evenly distributed across the heated track, as indicated by the dashed arrow 800. The current flow 800 is induced to flow more evenly to avoid current concentration at specific points. This limits the creation of hot spots. The heater track may have a resistivity gradient perpendicular to the current flow at the corners, such that the resistivity is higher on the inside of the corners and lower on the outside of the corners. Such gradients are beneficial in offsetting localized high current densities and reducing hot spot generation.

[0227] Figure 10 is a schematic diagram of the interior of an aerosol generating system 200 according to an embodiment of the present disclosure. The aerosol generating system 200 comprises two main components: a cartridge 300 and a main body or aerosol generating device 400. The cartridge 300 is detachably connected to the aerosol generating device 400. In this embodiment, the aerosol generating device 400 comprises a power source in the form of a battery 402, which is a rechargeable lithium-ion battery, and a device housing 401 that houses a control circuit 403. The aerosol generating system 200 is portable and has a size comparable to a conventional cigar or cigarette. A mouthpiece is located at the mouth end of the cartridge 300.

[0228] The cartridge 300 comprises a cartridge housing 304 that houses a heater assembly 100 and a liquid storage section or liquid storage portion 301 for holding a liquid aerosol forming substrate. The liquid aerosol forming substrate is conveyed downward from the liquid absorption surface 111 through the porous material to the heating element, and the vaporized aerosol forming substrate is released from the heating surface 112 when power is supplied to the heating element.

[0229] The cartridge 300 includes one or more air intake ports 302 formed within the cartridge housing 304 at positions along the length of the cartridge 300. The aerosol outlet 305 is located in the mouthpiece at the mouth end of the cartridge 300. The one or more air intake ports 302 are in fluid communication with the aerosol outlet 305 to define the airflow path through the cartridge 300 of the aerosol generating system 200. The airflow path flows from the one or more air intake ports 302 to the heater assembly 100 in the airflow channel. The heater assembly 100 is arranged to be in fluid communication with the airflow path in the airflow channel. Air enters the one or more air intake ports 302, passes through the airflow channel, through the heater assembly 100, and flows in the mean airflow direction.

[0230] In the embodiment shown in Figure 4, the liquid storage section 301 is arranged around a centrally sealed aerosol channel 303, which has an annular cross-section. When the airflow path reaches the heater assembly 100, it is redirected upward around the side of the heater assembly 100 and flows through the aerosol channel to the aerosol outlet 305.

[0231] The aerosol generating system 200 is configured so that a user can inhale or smoke the mouthpiece of a cartridge, thereby drawing an aerosol into their mouth through an aerosol outlet 305. During operation, when a user smokes the mouthpiece, air is drawn out through one or more air intake ports 302, along an airflow path through an airflow channel, through and around the heater assembly 100, and then drawn out along an airflow path through an aerosol channel 303 to the aerosol outlet 305. The control circuit 403 controls the supply of power from the battery 402 to the cartridge 300 when the system is started. This then controls the amount and characteristics of the vapor produced by the heater assembly 100. The control circuit 403 includes an airflow sensor (not shown) that supplies power to the heater assembly 100 when the airflow sensor detects user inhalation. This type of control device is well established in aerosol generating systems such as inhalers and e-cigarettes. When the user inhales vapor from the mouthpiece of cartridge 300, the heater assembly 100 is activated, generating vapor, which is carried into the airflow path. The vapor is cooled within the airflow path to form an aerosol, which is then inhaled into the user's mouth through the aerosol outlet 305.

Claims

1. an aerosol generation system, A heat-generating element for vaporizing the liquid aerosol-forming substrate, A porous body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous body has a liquid absorption surface and a heating surface, The heating element is located on the heated surface of the porous body, and the heating element and the porous body are integrally formed. The heater assembly comprises a porous body in which the average pore diameter of the porous body changes between the liquid absorption surface and the heating surface, The aerosol generating system further comprises an air intake and an aerosol outlet, wherein the air intake is in fluid communication with the aerosol outlet, defining an airflow path through the aerosol generating system. An aerosol generating system in which the heater assembly is arranged in fluid communication with the airflow path such that air flows through the heater assembly in the mean airflow direction, and the heater assembly and the airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

2. The porous body of the heater assembly has a heating end and a liquid absorption end, the heating surface is located at the heating end, and the liquid absorption surface is located at the liquid absorption end. The aerosol generating system according to claim 1, wherein the porous body has a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end, and the first average pore diameter is larger than the second average pore diameter.

3. The aerosol generating system according to claim 2, wherein the first average pore diameter is 5 micrometers to 200 micrometers.

4. The aerosol generating system according to claim 2 or 3, 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 diameter and the second porous material having the second average pore diameter.

5. The aerosol generating system according to any one of claims 1 to 4, wherein the area of ​​the heated surface of the porous body is smaller than the area of ​​the liquid-absorbing surface of the porous body.

6. The aerosol generating system according to any one of claims 1 to 5, wherein the ratio of the area of ​​the heated surface of the porous body to the area of ​​the liquid-absorbing surface of the porous body is 0.9 or less.

7. The aerosol generating system according to any one of claims 1 to 6, wherein the ratio of the area of ​​the heated surface of the porous body to the area of ​​the liquid-absorbing surface of the porous body is at least 0.

1.

8. The aerosol generating system according to any one of claims 1 to 7, wherein the ratio of the area of ​​the heated surface of the porous body to the area of ​​the liquid-absorbing surface of the porous body is 0.1 to 0.

9.

9. The aerosol generating system according to any one of claims 1 to 8, wherein the heated surface of the porous body is curved along one or both of a first transverse direction and a second transverse direction, and the first transverse direction is perpendicular to the second transverse direction.

10. The aerosol generating system according to any one of claims 1 to 9, wherein the heated surface is convex in one or both of the first transverse direction and the second transverse direction.

11. The aerosol generating system according to any one of claims 1 to 10, further comprising an insulating layer having a lower thermal conductivity than the porous body, wherein the insulating layer is disposed between and in contact with each of the porous ceramic body and the heating element, and the insulating layer is configured to reduce heat transfer from the heating element to the porous ceramic body.

12. The aerosol generating system according to any one of claims 1 to 11, wherein the heating element comprises a plurality of tracks or track portions electrically arranged in parallel.

13. The aerosol generating system according to any one of claims 1 to 12, wherein the heating element and the porous body are molded as a single monolithic piece.

14. The aerosol generating system according to any one of claims 1 to 10, wherein the heating element is the doped portion of the porous body.

15. An aerosol generating system according to any one of claims 1 to 14, comprising a cartridge, wherein the heater assembly is a component of the cartridge, and the cartridge further comprises a liquid storage portion configured to hold a liquid aerosol forming substrate, wherein the liquid storage portion is disposed on the liquid-absorbing surface of the porous body of the heater assembly.

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