Heater assembly with curved surface

Abstract

A heater assembly (300) for an aerosol generating system, the heater assembly (300) comprises a heating element (110) for vaporizing a liquid aerosol forming substrate and a porous body (320) for transporting the liquid aerosol forming substrate to the heating element (110), the porous body (320) having a liquid absorption surface (321), a heating surface (122), and at least one side extending from the liquid absorption surface (321) to the heating surface (122), The heating element (110) is located on the heating surface (122) of the porous body (320), the heating surface (122) of the porous body (120) is convex in one or both of the first transverse direction and the second transverse direction, the heating surface (122) of the porous body (120) has a different width (123) in the same transverse direction than the width (323) of the liquid absorption surface (321), and the porous body (320) includes a porous ceramic body or a porous glass body.

Description

Technical Field

[0001] The present invention relates to a heater assembly for an aerosol generation system. The present invention also relates to an aerosol generation system comprising the heater assembly.

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 a negative pressure is applied to 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, cooled to form an aerosol. The aerosol is then inhaled into the user's mouth through the mouthpiece.

[0003] In some other known aerosol generation systems, the aerosol generation system comprises a heater assembly having a resistive heating element located on a porous heating surface. The liquid aerosol-forming substrate is supplied from a liquid storage portion to the heating element through pores of the porous body by capillary action.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such aerosol generation systems, the vaporization of the liquid aerosol-forming substrate may be limited by the size of the porous body and the heated surface. However, the size of the porous body and the heated surface may be constrained by the shape, size, and configuration of the aerosol generation system and other components of the aerosol generation system. If the porous body is relatively small, it may be difficult to generate an acceptable aerosol.

[0005] Typically, the porous body of a heater assembly has a flat heating surface. In aerosol generating systems with such heater assemblies, the airflow adjacent to the heater assembly may become turbulent due to recirculation. This is especially true for airflow adjacent to the central region of the heater assembly. Turbulence adjacent to the heater assembly can lead to a reduction in the amount of aerosol-forming substrate vapor entrained in the air drawn through the aerosol generating system. This can adversely affect the quality of the generated aerosol.

[0006] Vapors not entrained in the air drawn through the aerosol generating system can condense and form large droplets of liquid aerosol-forming substrate. Inhalation of these large droplets of liquid aerosol-forming substrate can result in an unpleasant and undesirable user experience.

[0007] Vapors not entrained by the air drawn through the aerosol generating system may condense on the internal surfaces of the aerosol generating system. Condensation within the aerosol generating system can damage it, for example, by corroding the surface or damaging the circuitry.

[0008] It is desirable to provide heater assemblies that improve the quality of aerosols delivered to users. It is also desirable to provide heater assemblies that avoid or minimize damage to the aerosol generation system. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 shows a schematic perspective view of a heater assembly according to a first embodiment of the present invention. [Figure 2A] Figure 2A shows a schematic side view of another heater assembly according to a first embodiment of the present invention. [Figure 2B] Figure 2B shows a schematic side view of the porous body of the heater assembly shown in Figure 2A. [Figure 3] Figure 3 shows a schematic perspective view of another heater assembly according to a first embodiment of the present invention. [Figure 4] Figure 4 shows a schematic perspective view of another heater assembly according to a first embodiment of the present invention. [Figure 5] Figure 5 shows a schematic perspective view of another heater assembly according to a first embodiment of the present invention. [Figure 6A] Figure 6A shows a schematic example of a heating element track for a heating element in a heater assembly according to a first aspect of the present invention. [Figure 6B] Figure 6B shows a schematic example of a heating element track for a heating element in a heater assembly according to a first aspect of the present invention. [Figure 6C] Figure 6C shows a schematic example of a heating element track for a heating element in a heater assembly according to a first aspect of the present invention. [Figure 7A] Figure 7A shows a schematic example of current flow around the corner of the heating element track of the heating element of a heater assembly according to a first aspect of the present invention. [Figure 7B] Figure 7B shows a schematic example of current flow around the corner of the heating element track of the heating element of a heater assembly according to a first aspect of the present invention. [Figure 8A] Figure 8A shows a schematic plan view of a heater assembly according to a first embodiment of the present invention. [Figure 8B] Figure 8B shows a schematic cross-sectional view of the heater assembly shown in Figure 8A. [Figure 9] Figure 9 shows a schematic diagram of an aerosol generation system according to a second aspect of the present invention. [Figure 10] Figure 10 shows a schematic cross-sectional view of a part of an aerosol generating system according to a second embodiment of the present invention, illustrating the arrangement of the heater assembly in the airflow path within the aerosol generating system. [Figure 11] Figure 11 shows a schematic cross-sectional view of a part of another aerosol generating system according to a second embodiment of the present invention, illustrating the arrangement of a heater assembly in the airflow path within the aerosol generating system. [Modes for carrying out the invention]

[0010] This disclosure relates to a heater assembly for an aerosol generating 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 be porous. 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 surface of the porous body may be convex in one or both of a first transverse direction and a second transverse direction, the first transverse direction being perpendicular to the second transverse direction. The porous body may include a porous ceramic body or a porous glass body.

[0011] According to a first aspect of the present invention, a heater assembly for an aerosol generating system is provided, 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 surface of the porous body is convex in one or both of a first transverse direction and a second transverse direction, the first transverse direction is perpendicular to the second transverse direction, and the porous body includes a porous ceramic body or a porous glass body.

[0012] The present disclosure also relates to an aerosol generation system. The aerosol generation system may comprise a heater assembly as described above. The aerosol generation system may comprise a cartridge. The cartridge may include a liquid storage portion for storing a liquid aerosol forming substrate. The aerosol generation system may comprise an aerosol generator. The aerosol generator may comprise a power source for supplying power to the heater assembly. The aerosol generator may comprise a control circuit for controlling the supply of power from the power source to the heater assembly. The heater assembly may be a component of either the cartridge or the aerosol generator.

[0013] According to a second aspect of the present invention, there is provided an aerosol generation system comprising a heater assembly according to a first aspect of the present invention, a cartridge including a liquid storage portion for storing a liquid aerosol forming substrate, an aerosol generator including a power source for supplying power to the heater assembly and a control circuit for controlling the supply of power from the power source to the heater assembly, wherein the heater assembly is a component of either the cartridge or the aerosol generator.

[0014] As used herein, the term "liquid aerosol forming substrate" is used to denote a liquid substrate having the ability to release a volatile compound capable of forming an aerosol. Such a volatile compound may be released by heating the liquid aerosol forming substrate.

[0015] As used herein, the term "aerosol" is used to denote a dispersion of solid particles, droplets, or a combination of solid particles and droplets in a gas. An aerosol may be visible or invisible. An aerosol may include vapors of substances that are normally liquid or solid at room temperature, as well as solid particles, droplets, or a combination of solid particles and droplets.

[0016] As used herein, the terms "cartridge" and "aerosol generating cartridge" are used to denote a component that contains or is configured to contain a liquid aerosol-forming substrate. The cartridge interacts with an aerosol generating device to generate an aerosol.

[0017] As used herein, the term "aerosol generating device" is used to denote a device that interacts with a liquid aerosol-forming substrate to generate an aerosol.

[0018] As used herein, the term "heating element" is used to denote a component that transfers thermal energy to a liquid aerosol-forming substrate. Of course, the heating element may be located directly or indirectly on the porous body. Of course, the heating element may be integrally formed with the porous body.

[0019] As used herein, the term "porous body" denotes a component having a plurality of pores, at least some of which are interconnected. The porous body is configured to contain liquid within the plurality of pores. The porous body of the heater assembly according to the first aspect of the present invention includes a porous ceramic body or a porous glass body. The porous body may be a porous ceramic body or a porous glass body.

[0020] As used herein, the term "porous ceramic body" is used to denote a body or plug that includes porous ceramic, and the porous ceramic has a plurality of pores. The body or plug may be formed of a porous ceramic material.

[0021] As used herein, the term "heating surface" refers to the surface of the porous body closest to the heating element. The heating surface of the porous body may be in contact with the heating element.

[0022] As used herein, 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 configured to receive the liquid aerosol-forming substrate from the liquid storage portion or storage portion of the liquid aerosol-forming substrate.

[0023] As used herein, the term “longitudinal axis” is used to refer to the axis extending between the liquid-absorbing surface of the porous material and the heating surface of the porous material.

[0024] As used herein, the term “long axis direction” is used to indicate the direction between the liquid-absorbing surface of the porous material and the heating surface of the porous material. During use of the heater assembly, the liquid aerosol-forming substrate is drawn substantially along the long axis direction from the liquid-absorbing surface of the porous material to the heating surface of the porous material.

[0025] As used herein, the term “length” is used to indicate the maximum dimension in the longitudinal direction of a heater assembly, a component of a heater assembly, or a part of a heater assembly. The length of a heater assembly, a component of a heater assembly, or a part of a heater assembly may also be referred to as the height of the heater assembly, a component of a heater assembly, or a part of a heater assembly, respectively. The length of a heater assembly, a component of a heater assembly, or a part of a heater assembly may also be referred to as the thickness of the heater assembly, a component of a heater assembly, or a part of a heater assembly, respectively.

[0026] As used herein, the term “transverse direction” is used to indicate a direction perpendicular to the longitudinal axis. Unless otherwise stated, references to “sections” of heater assemblies, components of heater assemblies, or parts of heater assemblies refer to transverse sections.

[0027] As used herein, the term “width” means the maximum transverse dimension of a heater assembly, a component of a heater assembly, or a part of a heater assembly.

[0028] A heating assembly according to a first aspect of the present invention comprises a porous body having a heating surface that is convex in one or both of a first transverse direction and a second transverse direction, wherein the first transverse direction is perpendicular to the second transverse direction, and the porous body includes a porous ceramic body or a porous glass body. By including such a porous body, it may be possible to increase the surface area of ​​the heating surface without increasing the volume of the porous body. This may increase the efficiency of the heater assembly when vaporizing a liquid aerosol-forming substrate, as it may be possible to increase the surface area of ​​the heating assembly available for vaporizing a liquid aerosol-forming substrate without increasing the volume of the porous body through which heat loss can occur via conduction.

[0029] Providing a heating surface that is convex in one or both of the first and second transverse directions may allow for an increase in the surface area of ​​the heating surface without increasing its width. This may help increase the efficiency of the heater assembly in vaporizing the liquid aerosol-forming substrate while avoiding the need to redesign other components of the aerosol generation system to accommodate the porous material.

[0030] 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.

[0031] 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.

[0032] Improving the entrainment of vapor in the airflow through the aerosol generating system can 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.

[0033] The heated surface of the porous material may be convex in a single transverse direction.

[0034] The heated surface of the porous body may be convex in both the first transverse direction and the second transverse direction.

[0035] 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 to position the heater assembly 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.

[0036] If the heated surface is convex in a single transverse direction, the porous body may have a prismatic shape. The cross-sectional shape in the longitudinal direction of the porous body may be constant along the entire width of the porous body.

[0037] The porous body may contain one or more symmetrical planes along its long axis. This can simplify the assembly of the heater assembly within the cartridge or aerosol generator, as the orientation in which the heater assembly is inserted into the cartridge or aerosol generator may not be critical.

[0038] The porous body may contain at least two symmetrical planes along its major axis.

[0039] The porous material may include a plane in the direction of a first symmetrical major axis, and the first transverse direction is parallel to or included in the plane in the direction of the first symmetrical major axis. The porous material may include a plane in the direction of a second symmetrical major axis, and the second transverse direction is parallel to or included in the plane in the direction of the second symmetrical major axis. The porous material may include the plane in the direction of the first symmetrical major axis and the plane in the direction of the second symmetrical major axis.

[0040] The porous body may be symmetrical in the radial direction.

[0041] The heater assembly may have one or more symmetrical planes along its long axis. The heater assembly may have one or more symmetrical planes along its long axis that correspond to one or more symmetrical planes along its long axis in the porous body.

[0042] The heated surface of the porous body may have a radius of curvature of at least about 1.5 mm, at least about 2 mm, or at least about 2.5 mm in one or both of the first transverse direction and the second transverse direction.

[0043] The heated surface of the porous body may have a radius of curvature of about 10 mm or less, about 8 mm or less, or about 6 mm or less in one or both of the first transverse direction and the second transverse direction.

[0044] The heated surface of the porous body may have a radius of curvature of about 1.5 mm to about 10 mm, about 1.5 mm to about 8 mm, or about 1.5 mm to about 6 mm in one or both of the first transverse direction and the second transverse direction.

[0045] The heated surface of the porous material may have a radius of curvature of about 2 mm to about 10 mm, about 2 mm to about 8 mm, or about 2 mm to about 6 mm in one or both of the first transverse direction and the second transverse direction.

[0046] The heated surface of the porous body may have a radius of curvature of about 2.5 mm to about 10 mm, about 2.5 mm to about 8 mm, or about 2.5 mm to about 6 mm in one or both of the first transverse direction and the second transverse direction.

[0047] The smaller the radius of curvature of the heated surface, the larger the curvature of the heated surface.

[0048] The larger the radius of curvature of the heated surface, the smaller the curvature of the heated surface becomes.

[0049] The radius of curvature of the heating surface may be selected based on a balance between the desired surface area of ​​the heating surface and the length and width of the heater assembly. The radius of curvature of the heating surface may be selected to achieve the desired surface area of ​​the heating surface while minimizing the amount of material required to form the porous body of the heater assembly. The radius of curvature of the heating surface may also be selected to achieve an acceptable level of turbulence in the airflow adjacent to the heater assembly.

[0050] The radius of curvature of the heated surface in the first transverse direction may be different from the radius of curvature of the heated surface in the second transverse direction.

[0051] The radius of curvature of the heated surface of the porous material in the first transverse direction may be the same as the radius of curvature of the heated surface in the second transverse direction.

[0052] The curvature of the heated surface may vary at different locations on the heated surface. The curvature of the heated surface may vary at different locations on the heated surface along one or both of the first and second transverse directions.

[0053] The heated surface may be parabolic in one or both of the first and second transverse directions. The cross-sectional shape of the heated surface in the longitudinal direction may also be parabolic.

[0054] The radius of curvature of the heated surface as described herein may refer to the radius of curvature of the heated surface at the apex of the heated surface.

[0055] The heated surface may have a radius of curvature in the first transverse direction that is greater than about half the width of the heated surface in the first transverse direction. The heated surface may have a radius of curvature in the first transverse direction that is substantially equal to about half the width of the heated surface in the first transverse direction. The heated surface may have a radius of curvature in the first transverse direction that is at least about half the width of the heated surface in the first transverse direction.

[0056] The heated surface may have a radius of curvature in the second transverse direction that is greater than about half the width of the heated surface in the second transverse direction. The heated surface may have a radius of curvature in the second transverse direction that is substantially equal to about half the width of the heated surface in the second transverse direction. The heated surface may have a radius of curvature in the second transverse direction that is at least about half the width of the heated surface in the second transverse direction.

[0057] The ratio of the radius of curvature of a heated surface to the width of the heated surface in the same transverse direction may be at least about 0.5. For example, the ratio of the radius of curvature of a heated surface in a first transverse direction to the width of the heated surface in a first transverse direction may be at least about 0.5. As another example, the ratio of the radius of curvature of a heated surface in a second transverse direction to the width of the heated surface in a second transverse direction may be at least about 0.5. The ratio of the radius of curvature of a heated surface in a first transverse direction to the width of the heated surface in a first transverse direction may be at least about 0.5, and the ratio of the radius of curvature of a heated surface in a second transverse direction to the width of the heated surface in a second transverse direction may be at least about 0.5.

[0058] The ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction may be at least about 0.5, at least about 0.55, or at least about 0.6.

[0059] The ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction may be about 1.2 or less, about 1 or less, or about 0.8 or less. In some examples, the ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction may be about 5 or less, or about 2 or less.

[0060] The ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction may be approximately 0.5 to 5, 0.5 to 2, approximately 0.5 to 1.2, approximately 0.5 to 1, or approximately 0.5 to 0.8.

[0061] The ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction may be approximately 0.55 to 5, 0.55 to 2, 0.55 to 1.2, 0.55 to 1, or 0.55 to 0.8.

[0062] The ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction may be approximately 0.6 to 5, 0.6 to 2, 0.6 to 1.2, 0.6 to 1, or 0.6 to 0.8.

[0063] The ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the heated surface in the first transverse direction described above may be applicable to the ratio of the radius of curvature of the heated surface in the first transverse direction to the width of the porous body in the first transverse direction.

[0064] The ratio of the radius of curvature of the heating surface in the first transverse direction to the width of the heating surface in the first transverse direction described above may be applicable to the ratio of the radius of curvature of the heating surface in the first transverse direction to the width of the heater assembly in the first transverse direction.

[0065] The ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction may be at least about 0.5, at least about 0.55, or at least about 0.6.

[0066] The ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction may be about 1.2 or less, about 1 or less, or about 0.8 or less. In some examples, the ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction may be about 5 or less, or about 2 or less.

[0067] The ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction may be approximately 0.5 to 5, approximately 0.5 to 2, approximately 0.5 to 1.2, approximately 0.5 to 1, or approximately 0.5 to 0.8.

[0068] The ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction may be approximately 0.55 to 5, approximately 0.55 to 2, approximately 0.55 to 1.2, approximately 0.55 to 1, or approximately 0.55 to 0.8.

[0069] The ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction may be approximately 0.6 to 5, approximately 0.6 to 2, approximately 0.6 to 1.2, approximately 0.6 to 1, or approximately 0.6 to 0.8.

[0070] The ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the heated surface in the second transverse direction described above may be applicable to the ratio of the radius of curvature of the heated surface in the second transverse direction to the width of the porous body in the second transverse direction.

[0071] The ratio of the radius of curvature of the heating surface in the second transverse direction to the width of the heating surface in the second transverse direction described above may be applicable to the ratio of the radius of curvature of the heating surface in the second transverse direction to the width of the heater assembly in the second transverse direction.

[0072] The heating surface of the porous body may have a width in the first transverse direction that is less than or substantially equal to the width of the porous body in the first transverse direction.

[0073] The heating surface of the porous body may have a width in a first transverse direction that is substantially equal to the width of the porous body in a first transverse direction. The heating surface of the porous body may have a width in a first transverse direction that is substantially equal to the width of the heater assembly in a first transverse direction.

[0074] The heated surface of the porous material may have a width of at least about 2 mm, at least about 3 mm, or at least about 4 mm in the first transverse direction. In some examples, the heated surface of the porous material may have a width of at least about 0.5 mm in the first transverse direction.

[0075] The heated surface of the porous body may have a width of about 12 mm or less, about 10 mm or less, or about 8 mm or less in the first transverse direction.

[0076] The heated surface of the porous material may have a width of about 0.5 mm to about 12 mm, about 0.5 mm to about 10 mm, or about 0.5 mm to about 8 mm in the first transverse direction.

[0077] The heated surface of the porous material may have a width of approximately 2 mm to 12 mm, approximately 2 mm to 10 mm, or approximately 2 mm to 8 mm in the first transverse direction.

[0078] The heated surface of the porous body may have a width of approximately 3 mm to approximately 12 mm, approximately 3 mm to approximately 10 mm, or approximately 3 mm to approximately 8 mm in the first transverse direction.

[0079] The heated surface of the porous material may have a width of approximately 4 mm to 12 mm, approximately 4 mm to 10 mm, or approximately 4 mm to 8 mm in the first transverse direction.

[0080] As used herein, the width of the heated surface in the first transverse direction is used to indicate the maximum dimension of the heated surface in the first transverse direction.

[0081] The heating surface of the porous body may have a width in the second transverse direction that is less than or substantially equal to the width of the porous body in the second transverse direction.

[0082] The heating surface of the porous body may have a width in a second transverse direction that is substantially equal to the width of the porous body in a second transverse direction. The heating surface of the porous body may have a width in a second transverse direction that is substantially equal to the width of the heater assembly in a second transverse direction.

[0083] The heated surface of the porous material may have a width of at least about 2 mm, at least about 3 mm, or at least about 4 mm in the second transverse direction. In some examples, the heated surface of the porous material may have a width of at least 0.5 mm in the second transverse direction.

[0084] The heated surface of the porous body may have a width of about 12 mm or less, about 10 mm or less, or about 8 mm or less in the second transverse direction.

[0085] The heated surface of the porous material may have a width of approximately 0.5 mm to approximately 12 mm, approximately 0.5 mm to approximately 10 mm, or approximately 0.5 mm to approximately 8 mm in the second transverse direction.

[0086] The heated surface of the porous material may have a width of approximately 2 mm to 12 mm, approximately 2 mm to 10 mm, or approximately 2 mm to 8 mm in the second transverse direction.

[0087] The heated surface of the porous material may have a width of approximately 3 mm to 12 mm, approximately 3 mm to 10 mm, or approximately 3 mm to 8 mm in the second transverse direction.

[0088] The heated surface of the porous material may have a width of approximately 4 mm to 12 mm, approximately 4 mm to 10 mm, or approximately 4 mm to 8 mm in the second transverse direction.

[0089] When used herein, the width of the heated surface in the second transverse direction is used to indicate the maximum dimension of the heated surface in the second transverse direction.

[0090] The width of the heated surface in the first transverse direction may differ from the width of the heated surface in the second transverse direction.

[0091] The width of the heated surface in the first transverse direction may be the same as the width of the heated surface in the second transverse direction.

[0092] The heating surface of the porous body according to the first aspect of the present invention is curved. Therefore, the heating surface of the porous body has a length greater than 0 millimeters.

[0093] A substantially flat heating surface may have a substantially negligible length. In other words, a substantially flat heating surface may have a length of about 0 millimeters.

[0094] The heated surface of the porous body may have a length less than the length of the porous body.

[0095] The heated surface of the porous body may have a length of at least about 0.5 mm, at least about 1 mm, or at least about 1.5 mm.

[0096] The heated surface of the porous material may have a length of approximately 6 mm or less, approximately 5 mm or less, or approximately 4 mm or less.

[0097] The heated surface of the porous material may have a length of approximately 0.5 mm to approximately 6 mm, approximately 0.5 mm to approximately 5 mm, or approximately 0.5 mm to approximately 4 mm.

[0098] The heated surface of the porous material may have a length of approximately 1 mm to 6 mm, approximately 1 mm to 5 mm, or approximately 1 mm to 4 mm.

[0099] The heated surface of the porous material may have a length of approximately 1.5 mm to 6 mm, approximately 1.5 mm to 5 mm, or approximately 1.5 mm to 4 mm.

[0100] The length of the heating surface may be selected based on the desired curvature of the heating surface. For a given width of the heating surface, increasing the length of the heating surface can increase the curvature of the heating surface. For a given width of the heating surface, decreasing the length of the heating surface can decrease the curvature of the heating surface.

[0101] The width of the heated surface in one or both of the first and second transverse directions may be greater than the length of the heated surface.

[0102] The width of the heating surface in one or both of the first and second transverse directions may be greater than approximately twice the length of the heating surface. The width of the heating surface in one or both of the first and second transverse directions may be substantially equal to twice the length of the heating surface. The width of the heating surface in one or both of the first and second transverse directions may be at least approximately twice the length of the heating surface. In other words, the width of the heating surface in one or both of the first and second transverse directions may be approximately twice or more the length of the heating surface.

[0103] The width of the heated surface in one or both of the first and second transverse directions may be at least about 1 millimeter, at least about 2 millimeters, or at least about 3 millimeters greater than the length of the heated surface.

[0104] The width of the heated surface in one or both of the first and second transverse directions may be greater than the length of the heated surface by approximately 7 millimeters or less, approximately 6 millimeters or less, or approximately 5 millimeters or less.

[0105] The width of the heated surface in one or both of the first and second transverse directions may be approximately 1 to 7 millimeters, approximately 1 to 6 millimeters, or approximately 1 to 5 millimeters greater than the length of the heated surface.

[0106] The width of the heated surface in one or both of the first and second transverse directions may be approximately 2 to 7 mm, 2 to 6 mm, or 2 to 5 mm greater than the length of the heated surface.

[0107] The width of the heated surface in one or both of the first and second transverse directions may be approximately 3 to 7 mm, 3 to 6 mm, or 3 to 5 mm greater than the length of the heated surface.

[0108] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be at least about 0.02, at least about 0.05, at least about 0.1, at least about 0.15, or at least about 0.2.

[0109] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be about 0.5 or less, about 0.45 or less, or about 0.4 or less.

[0110] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be about 0.02 to about 0.5, about 0.02 to about 0.45, or about 0.02 to about 0.4.

[0111] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be about 0.05 to about 0.5, about 0.05 to about 0.45, or about 0.05 to about 0.4.

[0112] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be about 0.1 to about 0.5, about 0.1 to about 0.45, or about 0.1 to about 0.4.

[0113] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be approximately 0.15 to approximately 0.5, approximately 0.15 to approximately 0.45, or approximately 0.15 to approximately 0.4.

[0114] The ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions may be about 0.2 to about 0.5, about 0.2 to about 0.45, or about 0.2 to about 0.4.

[0115] For example, the ratio of the length to the width of the heated surface in one or both of the first and second transverse directions may be about 0.33. In other words, the length of the heated surface may be about 1 / 3 of the width of the heated surface in one or both of the first and second transverse directions.

[0116] The ratio of the length to the width of the heated surface in one or both of the first and second transverse directions may be selected based on the desired curvature of the heated surface. Increasing the ratio of the length to the width of the heated surface in a transverse direction can increase the curvature of the heated surface in that transverse direction. Decreasing the ratio of the length to the width of the heated surface in a transverse direction can decrease the curvature of the heated surface in that transverse direction.

[0117] The ratio of the length of the heated surface to the length of the porous body may be at least about 0.05, at least about 0.1, or at least about 0.15.

[0118] The ratio of the length of the heated surface to the length of the porous body may be approximately 0.45 or less, approximately 0.4 or less, or approximately 0.35 or less.

[0119] The ratio of the length of the heated surface to the length of the porous body may be approximately 0.05 to 0.45, approximately 0.05 to 0.4, or approximately 0.05 to 0.35.

[0120] The ratio of the length of the heated surface to the length of the porous body may be approximately 0.1 to 0.45, approximately 0.1 to 0.4, or approximately 0.1 to 0.35.

[0121] The ratio of the length of the heated surface to the length of the porous body may be approximately 0.15 to 0.45, approximately 0.15 to 0.4, or approximately 0.15 to 0.35.

[0122] The ratio of the length of the heated surface to the length of the porous body described above may be applicable to the ratio of the length of the heated surface of the porous body to the length of the heater assembly.

[0123] The heated surface of the porous body may have a surface area of ​​at least about 1 square millimeter, at least about 3 square millimeters, or at least about 5 square millimeters.

[0124] The heated surface of the porous body may have a surface area of ​​approximately 50 square millimeters or less, approximately 45 square millimeters or less, or approximately 40 square millimeters or less.

[0125] The heated surface of the porous body may have a surface area of ​​approximately 1 square millimeter to approximately 50 square millimeters, or approximately 1 square millimeter to approximately 45 square millimeters, or approximately 1 square millimeter to approximately 40 square millimeters.

[0126] The heated surface of the porous body may have a surface area of ​​approximately 3 square millimeters to approximately 50 square millimeters, or approximately 3 square millimeters to approximately 45 square millimeters, or approximately 3 square millimeters to approximately 40 square millimeters.

[0127] The heated surface of the porous body may have a surface area of ​​approximately 5 square millimeters to approximately 50 square millimeters, or approximately 5 square millimeters to approximately 45 square millimeters, or approximately 5 square millimeters to approximately 40 square millimeters.

[0128] As used herein, the surface area of ​​the heated surface does not take into account the porosity of the heated surface.

[0129] The surface area of ​​the heated surface of the porous material can be selected to generate an aerosol of acceptable quality while conforming to constraints on the size of the porous material.

[0130] The heated surface of the porous material may have a surface area greater than the square of the width of the heated surface in one or both of the first and second transverse directions.

[0131] The heated surface of the porous material may have a surface area at least about 10 percent, at least about 15 percent, or at least about 20 percent larger than the square of the width of the heated surface in one or both of the first and second transverse directions.

[0132] The heated surface of the porous material may have a surface area that is about 55 percent or less, about 45 percent or less, or about 35 percent or less than the square of the width of the heated surface in one or both of the first transverse direction and the second transverse direction.

[0133] The heated surface of the porous material may have a surface area that is about 10 to 55 percent, about 10 to 45 percent, or about 10 to 35 percent larger than the square of the width of the heated surface in one or both of the first and second transverse directions.

[0134] The heated surface of the porous material may have a surface area that is about 15 to 55 percent, about 15 to 45 percent, or about 15 to 35 percent larger than the square of the width of the heated surface in one or both of the first and second transverse directions.

[0135] The heated surface of the porous material may have a surface area that is about 25 to 55 percent, about 25 to 45 percent, or about 25 to 35 percent larger than the square of the width of the heated surface in one or both of the first and second transverse directions.

[0136] The relationship between the surface area and width of the heated surface in one or both of the first and second transverse directions can be selected based on the desired available area for heating the liquid aerosol-forming substrate and the curvature of the heated surface of the porous material. For a given width of the heated surface of the porous material, the curvature of the heated surface can be increased by increasing the surface area of ​​the heated surface. For a given width of the heated surface of the porous material, the curvature of the heated surface can be decreased by decreasing the surface area of ​​the heated surface.

[0137] The porous body may have a width of at least about 2 millimeters, at least about 3 millimeters, or at least about 4 millimeters in one or both of the first and second transverse directions. In some examples, the porous body may have a width of at least about 0.5 millimeters in one or both of the first and second transverse directions.

[0138] The porous body may have a width of about 12 millimeters or less, about 10 millimeters or less, or about 8 millimeters or less in one or both of the first transverse direction and the second transverse direction.

[0139] The porous body may have a width of about 0.5 mm to about 12 mm, about 0.5 mm to about 10 mm, or about 0.5 mm to about 8 mm in one or both of the first and second transverse directions.

[0140] The porous body may have a width of about 2 mm to about 12 mm, about 2 mm to about 10 mm, or about 2 mm to about 8 mm in one or both of the first and second transverse directions.

[0141] The porous body may have a width of about 3 mm to about 12 mm, about 3 mm to about 10 mm, or about 3 mm to about 8 mm in one or both of the first and second transverse directions.

[0142] The porous body may have a width of about 4 mm to about 12 mm, about 4 mm to about 10 mm, or about 4 mm to about 8 mm in one or both of the first and second transverse directions.

[0143] The width of the porous body in one or both of the first and second transverse directions may vary along the length of the porous body. As will be further described below, the porous body may have a shape that tapers, for example, from the liquid-absorbing surface of the porous body toward the heating surface of the porous body, or from the heating surface of the porous body toward the liquid-absorbing surface.

[0144] The porous body may have a length of at least about 1 millimeter, at least about 3 millimeters, or at least about 4 millimeters.

[0145] The porous body may have a length of approximately 10 mm or less, approximately 9 mm or less, or approximately 8 mm or less.

[0146] The porous body may have a length of approximately 1 mm to 10 mm, approximately 1 mm to 9 mm, or approximately 1 mm to 8 mm.

[0147] The porous body may have a length of approximately 3 mm to 10 mm, approximately 3 mm to 9 mm, or approximately 3 mm to 8 mm.

[0148] The porous body may have a length of approximately 4 mm to 10 mm, approximately 4 mm to 9 mm, or approximately 4 mm to 8 mm.

[0149] The heater assembly may have a width of at least about 2 millimeters, at least about 3 millimeters, or at least about 4 millimeters in one or both of the first and second transverse directions. In some examples, the heating assembly may have a width of at least about 0.5 millimeters in one or both of the first and second transverse directions.

[0150] The heater assembly may have a width of approximately 12 mm or less, approximately 10 mm or less, or approximately 8 mm or less in one or both of the first and second transverse directions.

[0151] The heater assembly may have a width of approximately 0.5 mm to approximately 12 mm, approximately 0.5 mm to approximately 10 mm, or approximately 0.5 mm to approximately 8 mm in one or both of the first and second transverse directions.

[0152] The heater assembly may have a width of approximately 2 mm to approximately 12 mm, approximately 2 mm to approximately 10 mm, or approximately 2 mm to approximately 8 mm in one or both of the first and second transverse directions.

[0153] The heater assembly may have a width of approximately 3 mm to approximately 12 mm, approximately 3 mm to approximately 10 mm, or approximately 3 mm to approximately 8 mm in one or both of the first and second transverse directions.

[0154] The heater assembly may have a width of approximately 4 mm to approximately 12 mm, approximately 4 mm to approximately 10 mm, or approximately 4 mm to approximately 8 mm in one or both of the first and second transverse directions.

[0155] The heater assembly may have a length of at least about 1 millimeter, at least about 3 millimeters, or at least about 4 millimeters.

[0156] The heater assembly may have a length of approximately 10 mm or less, approximately 9 mm or less, or approximately 8 mm or less.

[0157] The heater assembly may have a length of approximately 1 mm to 10 mm, approximately 1 mm to 9 mm, or approximately 1 mm to 8 mm.

[0158] The heater assembly may have a length of approximately 3 mm to 10 mm, approximately 3 mm to 9 mm, or approximately 3 mm to 8 mm.

[0159] The heater assembly may have a length of approximately 4 mm to 10 mm, approximately 4 mm to 9 mm, or approximately 4 mm to 8 mm.

[0160] The liquid-absorbing surface body may be substantially flat.

[0161] The porous body may include at least one surface along its long axis extending from the liquid-absorbing surface to the heating surface. As used herein, the surface along its long axis may also be referred to as a side or side wall.

[0162] At least one side of the porous body may be substantially perpendicular to the liquid-absorbing surface. Each of the sides of the porous body may be substantially perpendicular to the liquid-absorbing surface.

[0163] The liquid-absorbing surface of the porous material may have a different area from the heated surface of the porous material. As used herein, the area of ​​the liquid-absorbing surface may also be referred to as the surface area of ​​the liquid-absorbing surface. As used herein, the area of ​​the heated surface may also be referred to as the surface area of ​​the heated surface.

[0164] 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 for vaporizing the aerosol-forming substrate. Inefficient heater assemblies may result in reduced aerosol throughput.

[0165] Advantageously, providing a porous body in which the heating surface and the liquid absorption surface have different areas can improve the throughput of aerosols that can be generated by the heater assembly compared to a heater assembly in which the heating surface has the same area as the liquid absorption surface.

[0166] For example, in a heater assembly where the area of ​​the porous heating surface is less than the area of ​​the porous liquid absorption surface, heat flow from the heating element to the liquid absorption surface and then to the liquid storage portion by conduction may be reduced. A relatively small heating surface provides a small heat transfer area for heat to be transferred by conduction from the heating element to the porous material and then to the liquid absorption surface.

[0167] 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 throughput of aerosols generated by the heater assembly.

[0168] For example, in a heater assembly where the area of ​​the porous liquid-absorbing surface is less 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.

[0169] 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 materials with a shape such that the liquid-absorbing surface has a smaller area than the heated surface can provide increased heating efficiency, which can increase the throughput of aerosols generated by the heater assembly.

[0170] Increased heating efficiency may reduce power consumption during use of the heater assembly.

[0171] The area of ​​the heated surface of the porous material may be less 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 greater than the area of ​​the heated surface of the porous material.

[0172] 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 from the heating element to the liquid-absorbing surface and then to the liquid storage portion can be reduced by conduction. The relatively small heated surface provides a small heat transfer area for heat to be transferred by conduction from the heating element to the porous material and then to the liquid-absorbing surface.

[0173] 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 throughput of aerosols generated by the heater assembly.

[0174] 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, allowing the aerosol-forming substrate delivered to the heating surface to vaporize. In other words, the size and shape of the heating surface can more closely match the size and shape of the heating element. As a result, more liquid aerosol-forming substrate may be delivered from the liquid absorption surface to the area of ​​the heating surface closer to the heating element, which can lead to the vaporization of more liquid aerosol-forming substrate on 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 can allow for maximization of the power density on the heating surface, which also improves heating efficiency.

[0175] Advantageously, a liquid absorption surface with a larger surface area than the heating surface may allow the liquid absorption surface to receive a larger amount of liquid aerosol substrate from the liquid storage portion. As a result of the relatively small surface area of ​​the heating surface, 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 can increase the aerosol throughput generated by the heater assembly.

[0176] The heating surface area of ​​the porous material may be larger than the liquid-absorbing surface area of ​​the porous material. The liquid-absorbing surface area of ​​the porous material may be smaller than the heating surface area of ​​the porous ceramic body.

[0177] Advantageously, if the porous material has a shape such that the liquid absorption surface has a smaller area than the heating surface, the smaller area of ​​the liquid absorption surface can cause a reduction in heat 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, a porous material with a shape such that the liquid absorption surface has a smaller area than the heating surface can provide increased heating efficiency, which can increase the throughput of aerosols generated by the heater assembly.

[0178] Advantageously, a porous material 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, allowing the aerosol-forming substrate delivered to the heating surface to vaporize. 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 delivered from the liquid absorption surface to the area of ​​the heating surface closer to the heating element, which can lead to more liquid aerosol-forming substrate vaporization on the heating surface. An increase in the vaporized liquid aerosol-forming substrate can increase the aerosol throughput generated by the heater assembly.

[0179] The heated surface of a porous material may have a width different from the width of the liquid-absorbing surface of the porous material in the same transverse direction. For example, the heated surface of a porous material may have a width in a first transverse direction that is different from the width of the liquid-absorbing surface of the porous material in the first transverse direction. The heated surface of a porous material may have a width in a second transverse direction that is different from the width of the liquid-absorbing surface of the porous material in the second transverse direction. The heated surface of a porous material may have a width in a first transverse direction that is different from the width of the liquid-absorbing surface of the porous material in the first transverse direction, and the heated surface of a porous material may have a width in a second transverse direction that is different from the width of the liquid-absorbing surface of the porous material in the second transverse direction.

[0180] If the width of the heated surface of a porous material differs from the width of the liquid-absorbing surface of the porous material in the same transverse direction, the flow of the liquid aerosol-forming substrate to different regions of the heated surface of the porous material may vary. For example, the flow path of the liquid aerosol-forming substrate to the edge of the heated surface of the porous material may be longer than the flow path of the liquid aerosol-forming substrate to the central region of the heated surface.

[0181] The combination of the convex shape of the heated surface of the porous material and the fact that the width of the heated surface differs from the width of the liquid-absorbing surface of the porous material in the same transverse direction can reduce any differences in the flow path of the liquid aerosol-forming substrate to different regions of the heated surface of the porous material. This can advantageously help facilitate the uniform release of volatile compounds from the liquid aerosol-forming substrate across the heated surface of the porous material. More uniform release of volatile compounds across the heated surface of the porous material can advantageously lead to the generation of a more homogeneous aerosol.

[0182] The width of the heated surface of the porous material may be less than the width of the liquid-absorbing surface of the porous material in the same transverse direction.

[0183] The heated surface of the porous material may have a width in a first transverse direction that is less than the width of the liquid-absorbing surface of the porous material in the first transverse direction. The heated surface of the porous material may have a width in a second transverse direction that is less than the width of the liquid-absorbing surface of the porous material in the second transverse direction. The heated surface of the porous material may have a width in a first transverse direction that is less than the width of the liquid-absorbing surface of the porous material in the first transverse direction, and the heated surface of the porous material may have a width in a second transverse direction that is less than the width of the liquid-absorbing surface of the porous material in the second transverse direction.

[0184] The width of the heated surface of the porous material may be greater than the width of the liquid-absorbing surface of the porous material in the same transverse direction. The heated surface of the porous material may have a width in a first transverse direction that is greater than the width of the liquid-absorbing surface of the porous material in the first transverse direction. The heated surface of the porous material may have a width in a second transverse direction that is greater than the width of the liquid-absorbing surface of the porous material in the second transverse direction. The heated surface of the porous material may have a width in a first transverse direction that is greater than the width of the liquid-absorbing surface of the porous material in the first transverse direction, and the heated surface of the porous material may have a width in a second transverse direction that is greater than the width of the liquid-absorbing surface of the porous material in the second transverse direction.

[0185] The porous body may have a shape that tapers along at least a portion of its length. The porous body may also have a shape that tapers along its entire length.

[0186] The flow of liquid aerosol-forming substrate to different regions of the heated surface of a porous material can vary in porous materials having a shape that tapers along at least a portion of its length. For example, the flow path of liquid aerosol-forming substrate to the edge of the heated surface of a porous material may be longer than the flow path of liquid aerosol-forming substrate to the central region of the heated surface.

[0187] The combination of a porous material having a convex heating surface and a porous material with a tapered shape along at least a portion of its length can reduce any differences in the flow path of the liquid aerosol-forming substrate to different regions of the porous material's heating surface. This can advantageously help facilitate the uniform release of volatile compounds from the liquid aerosol-forming substrate across the porous material's heating surface. More uniform release of volatile compounds across the porous material's heating surface can advantageously lead to the generation of a more homogeneous aerosol.

[0188] The porous material may include a shape that tapers from the liquid-absorbing surface toward the heating surface.

[0189] The porous body may include a shape that tapers from the heated surface toward the liquid-absorbing surface.

[0190] A porous body includes a porous ceramic body or a porous glass body. In other words, a porous body may be a body containing a porous ceramic, which has a plurality of pores, at least some of which are interconnected. A porous body may also be a body containing a porous glass, which has a plurality of pores, at least some of which are interconnected.

[0191] Porous materials may have been manufactured by sintering. Porous materials may have been manufactured by directly sintering ceramic powder to form a porous material with pores between interconnected powder particles. Porous materials may have been manufactured by using sacrificial material in ceramic powder, where the sacrificial material is used as a spacer to form pores. The sacrificial material may have burned out during sintering.

[0192] Porous materials can be advantageously thermally stable at the temperatures in which heater assemblies typically operate. Furthermore, porous materials can have significantly higher thermal decomposition temperatures than conventional wicks. This can help reduce the risk of unwanted byproducts being generated during the use of the heater assembly.

[0193] The porous body may comprise any suitable inert ceramic or biocompatible ceramic. 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 Al2O3, ZrO2, Ca2SiO2. 3、The porous material may include one or more of the following: Si3N4, SiC, Ti3AlC2, BN, AlN, SiO2, MgO, mica, diatomaceous earth, silicates, borides, and glass. The porous material may include ceramics containing one or more of the following: Al2O3, ZrO2, SiO2, and Ca2SiO3. In a preferred example, the porous material includes ceramics containing either or both of SiO2 and Ca2SiO3.

[0194] The porous material may be substantially incompressible.

[0195] The porous material may have a porosity of approximately 30 percent to approximately 70 percent.

[0196] The average pore size of a porous material can vary between the liquid-absorbing surface and the heated surface.

[0197] 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.

[0198] 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 on the liquid-absorbing surface to relatively small pores on the heated surface.

[0199] 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.

[0200] Providing a porous body having a larger average pore diameter at the liquid absorption end and a smaller average pore diameter at the heating end can particularly facilitate the efficient transport of a liquid aerosol-forming substrate from the liquid absorption end to the heating end of the porous body without allowing leakage. In particular, the inventors of the present invention have identified that the liquid aerosol-forming substrate is transported 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, and the surface tension of the liquid aerosol-forming substrate. 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 transport of the liquid aerosol-forming substrate to the heating surface of the porous body.

[0201] Firstly, in order to provide efficient capillary flow of liquid through a porous material, the capillary pressure must overcome the viscous drag pressure. Secondly, in order to prevent leakage, the inertial force must not overcome 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.

[0202] 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.

[0203] 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 of the heating element include, but are not limited to, strips, flakes, filaments, wires, meshes, spiral coils, fibers, or cloths.

[0204] The heating element may comprise 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 having spaces between them. The term “mesh” also includes woven fabrics and nonwoven fabrics.

[0205] 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. If the heating element includes a mesh or cloth of filaments, the filaments may be formed individually or woven together.

[0206] The heating element may include an electrically resistant heating element. The heating element may be formed 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 ceramics 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. Examples of suitable metal alloys include stainless steel, constantan, nickel-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium-containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, iron-containing alloys, nickel-based superalloys, iron-based superalloys, cobalt-based superalloys, 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.

[0207] 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.

[0208] The electric heating element may be formed from a conductive material deposited on the heating surface of a porous body. As used herein, the term "conductive material" means 1x10 -2 This refers to a material having a resistivity of 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 is not simply laid on or fixed to a porous body as a pre-formed solid component, but subsequently condenses or aggregates to form an electrically heating element.

[0209] The electric heating element may be deposited directly onto the heating surface of the porous material. In other words, the conductive material forming the electric heating element is deposited onto the heating surface of the porous material such that the electric heating element is in direct contact with the heating surface of the porous material.

[0210] In some examples, the conductive material of the electric heating element may diffuse, at least partially, into the heating surface of the porous body. As used herein, the term “diffuse into the porous outer surface” means that the conductive material penetrates into the material of the heating surface of the porous body at the boundary between the conductive material and the porous body, for example, by extending into the pores of the porous outer surface. 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 by increasing contact between the electric heating element and the porous body.

[0211] The conductive material forming the electric heating element may be deposited onto the heating surface of the porous body in any preferred manner. For example, the conductive material may be deposited as a liquid onto the heating surface of the porous body using a dispensing pipette or syringe, or using a micro-tip transfer device such as a needle.

[0212] The heating element may include a printable conductive material printed on the heating surface of a porous body. The printable conductive material may be printed on the heating surface of the porous body using any suitable known printing technique, such as one or more of screen printing, gravure printing, flex printing, or inkjet printing. Such printing processes may be particularly applicable to high-speed manufacturing processes.

[0213] Alternatively, the conductive material forming the electric heating element may be deposited onto the heated surface of the porous body by one or more vacuum deposition processes, such as vapor deposition and sputtering.

[0214] The heating element may be formed from any suitable conductive material. The conductive material may include one or more of metals, conductive polymers, and conductive ceramics.

[0215] Suitable conductive metals include, but are not limited to, aluminum, silver, nickel, gold, platinum, copper, tungsten, and alloys thereof. The conductive material may also contain metal powder suspended in an adhesive such as epoxy resin. In one embodiment, the conductive material comprises an epoxy with silver attached.

[0216] Suitable conductive polymers include, but are not limited to, 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 any combination thereof.

[0217] Suitable conductive ceramics include ITO (indium tin oxide), SLT (lanthanum-doped strontium titanate), SYT (yttrium-doped strontium titanate), or combinations thereof.

[0218] 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 heated surface of a porous body, to increase the amount of conductive material that diffuses into the heated surface of the porous body, to shorten the time it takes for the conductive material to cure, 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 heated surface of the porous body.

[0219] The heating element may include multiple tracks or track sections arranged electrically 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.

[0220] At least two of the electrically parallel heating tracks may have similar resistances to each other, or they may have the same resistance to each other. Preferably, all electrically parallel heating tracks have similar or the same resistance to each other. The electrically parallel heating tracks may have different resistances, which is particularly beneficial in heater assemblies where it is advantageous for the heating element zones to generate 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 resistance (and thus generate more heat) than the heating track in the center of the heating element.

[0221] The heating element may include 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.

[0222] 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. One or more 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 include a converging portion. In the converging portion, the current is coupled from the track portions defining electrically parallel paths to the second connection pad.

[0223] Various different arrangements of electrically parallel tracks or track sections are possible. The heating element may include two, three, four or more track sections that define electrically parallel paths.

[0224] By electrically arranging tracks or track sections in parallel, if one track section is faulty, the current can be redistributed and still flow through the heating element, i.e., the electrical connection between the first and second connecting pads is not damaged. In contrast, in a simple meandering heater that defines a single electrical path between the first and second connecting pads, if a part of the meandering heating element is damaged or faulty, this can lead to an increase in local resistance, resulting in increased power consumption and potentially further increasing resistance until failure occurs.

[0225] 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 advantageously 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 it is provided 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 potential for a future decrease in the optimal performance of the heater assembly. Electrically parallel tracks have the advantage of increasing the number of fume extractions before the heater completely fails, potentially extending the heater's lifespan to the end of the device's life.

[0226] The heating element may include a plurality of tracks or track portions that define a path having at least one bend, the inner edge of the bend being curved.

[0227] The curved inner edge of the bend has the advantage of guiding the current to flow more evenly around at least one bend. This reduces the current concentration and limits the generation of hot spots.

[0228] The heating element may include multiple tracks or track sections having an electrical resistivity gradient perpendicular to the current flow at a corner or multiple corners, resulting in higher electrical resistivity in the inner part of the corner and lower resistivity in the outer part of the corner. Such gradients are beneficial for offsetting localized high current densities and reducing hotspot formation.

[0229] The heating element may include multiple tracks or track sections arranged at a distance between at least two of multiple tracks or track sections within a range of 200 to 300 micrometers.

[0230] 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.

[0231] The heating element is located on the heated surface of the porous body. As used herein, a heating element located on a porous body does not exclude a heater assembly that includes one or more components located between the heating element and the heated surface of the porous body.

[0232] The heater assembly may include one or more components located between the heating element and the porous body. As will be further described below, the heater assembly may include an insulating layer located between the porous body and the heating element.

[0233] The heating element may be located directly on the heated surface of the porous body. There may be no heater assembly components located between the porous body and the heating element. The heating element may be in contact with the entire heated surface of the porous body.

[0234] The heating element may extend over at least a large portion of the heated surface of the porous body. The heating element may extend over substantially all of the heated surface of the porous body.

[0235] At least a large portion of the heating element may be in contact with the heated surface of the porous material. The entire heating element may be in contact with the heated surface of the porous material.

[0236] The heating element may be convex in one or both of the first and second transverse directions.

[0237] 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.

[0238] The characteristics related to the curvature of the heated surface of the porous material described above may be applicable to the curvature of the heating element.

[0239] The characteristics related to the dimensions of the heated surface of the porous material described may be applicable to the dimensions of the heating element.

[0240] In particular, the radius of curvature of the porous body, the relationship between the radius of curvature and width, width, length, the relationship between width and length, surface area, and the ratio of surface area to the width of the heated surface may be applicable to the relationship between the radius of curvature and width, width, length, the relationship between width and length, surface area, and the ratio of surface area to the width of the heating element, respectively. The relationship between the length of the heated surface of the porous body and the length of the porous body may be applicable to the relationship between the length of the heating element and the length of the porous body.

[0241] The porous body and the heating element may be formed as two separate parts assembled together.

[0242] The heating element may be bonded to the heating surface of the porous body. The advantage of providing a heater assembly in which the heating element is bonded to the heating surface of a porous ceramic body is that a robust and reliable connection can be established between the heating element and the porous ceramic body. This can, advantageously, help improve heat transfer between the heating element and the porous ceramic body.

[0243] Alternatively, the heating element and the porous body may be formed integrally. Providing a heating element formed integrally with the porous body may, advantageously, provide a more robust and reliable connection between the heating element and the porous body. This may, advantageously, help improve heat transfer between the heating element and the porous body.

[0244] 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, in turn, can provide users of the aerosol generating system with an improved and more comfortable experience. Such arrangements can also help reduce the likelihood of users experiencing dry heating or dry fumes.

[0245] The advantage of integrally forming the heating element with the porous body is that it helps mitigate manufacturing tolerance issues encountered 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 in supplying the heating element with the liquid aerosol-forming substrate. This also helps prevent undesirable heat loss, which contributes to improved energy efficiency.

[0246] 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 reduced material requirements in the overall aerosol generation system is the provision of a more sustainable and environmentally friendly solution.

[0247] 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 made 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.

[0248] The heating element may be a doped portion of a porous material.

[0249] The porous material may be doped such that a portion of the porous material acting as a heat-generating element is conductive. Doping the porous material may 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, which involve depositing the heat-generating element by thin-film or thick-film techniques, which can reduce the properties of the porous material, particularly the porosity. 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.

[0250] The heater assembly may include an insulating layer. The insulating layer may have a lower thermal conductivity than the porous body. The insulating layer may be placed between the porous body and the heating element. The insulating layer may be in contact with one or both of the porous body and / or the heating element. The insulating layer may be configured to reduce heat transfer from the heating element to the porous body.

[0251] For example, the heater assembly may include an insulating layer having a lower thermal conductivity than the porous body, the insulating layer being positioned between the porous body and the heating element and in contact with them, and the insulating layer being configured to reduce heat transfer from the heating element to the porous body.

[0252] In an insulating layer, heat loss from the heating element to the porous body and the liquid within the porous body can be reduced. This can provide a more efficient heater assembly that can increase the amount and number of times the device can be used by the user before the device power source, such as a battery, is depleted. The inventors estimated that in known devices, about one-third of the energy from the heating element can be lost through conduction through the porous body and the liquid within the porous body. The remaining two-thirds are used to generate aerosols by heating the liquid aerosol-forming substrate. In an insulating layer, these energy losses can be reduced. Specifically, the insulating layer can reduce heat propagation or conduction from the heating element to or through the porous body. This reduction in conduction can concentrate heat on the heated surface of the porous body, minimize heat dissipation, and increase the heating efficiency of the heater assembly.

[0253] As used herein, the term "thermal insulation" refers to a property that reduces or limits heat transfer. A more thermally insulating component transfers less heat by conduction, convection, or radiation than a more thermally insulating component.

[0254] The insulating layer may contain an insulating material. The insulating material may have a lower thermal conductivity than the porous material. The insulating material may also have a higher porosity than the porous material. This has the advantage of providing an insulating layer that is easy to manufacture while being particularly effective in reducing energy loss.

[0255] The insulating layer may include a material having a thermal conductivity of less than 40 watts / meter Kelvin. This has the advantage of providing an insulating layer that is particularly effective in reducing energy loss through the porous material. The insulating layer may also include a material having a thermal conductivity of less than 10 watts / meter Kelvin. This has the advantage of providing an insulating layer that is particularly effective in reducing energy loss through the porous material.

[0256] The insulating layer may extend completely between the porous material and the heat-generating element. This has the advantage of more effectively providing a barrier between the heat-generating element and the porous material, and is therefore particularly effective in reducing energy loss through the porous material.

[0257] 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.

[0258] 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.

[0259] The insulation layer may have a thickness of 0.1 mm to 2 mm. An insulation layer having this thickness is particularly suitable for reducing energy loss from the heat-generating element to the porous material. Preferably, the insulation layer has a thickness of 0.5 mm to 1.5 mm. An insulation layer having this thickness is even more suitable for reducing energy loss from the heat-generating element to the porous material.

[0260] The thermal insulation layer may be convex in one or both of the first and second transverse directions.

[0261] The curvature of the insulating layer in the first transverse direction may be substantially the same as the curvature of the heated surface of the porous body in the first transverse direction. The curvature of the insulating layer in the second transverse direction may be substantially the same as the curvature of the heated surface of the porous body in the second transverse direction. The curvature of the insulating layer in both the first and second transverse directions may be substantially the same as the curvature of the heated surface of the porous body in both the first and second transverse directions, respectively.

[0262] The heater assembly may include a first electrical contact and a second electrical contact connected to a heating element. Each electrical contact may be located on an opposing side or edge of the heating surface of the porous body. The heating element may extend between the electrical contacts. The heating elements may form electrical connections between them.

[0263] 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.

[0264] The first and second electrical contacts may be formed from a conductive material deposited directly onto the heated surface of the porous body.

[0265] The heating element may extend in a wavy or meandering manner between electrical contacts. This may help increase the length of the heating element between electrical contacts in contact with the heated surface, thereby helping to improve the heating of the liquid aerosol-forming substrate.

[0266] According to a second aspect of the present invention, an aerosol generating system is provided, comprising a heater assembly according to a first aspect of the present invention, a cartridge including a liquid storage portion for storing a liquid aerosol forming substrate, and an aerosol generating device including a power supply for supplying power to the heater assembly and a control circuit for controlling the power supply from the power supply to the heater assembly, wherein the heater assembly is a component of either the cartridge or the aerosol generating device.

[0267] The heating element of the heater assembly may be for vaporizing the liquid aerosol-forming substrate stored in the liquid storage portion of the cartridge.

[0268] The heater assembly may be a component of the cartridge. Therefore, the aerosol generating system may include a cartridge comprising a liquid storage portion for storing a liquid aerosol forming substrate according to a first aspect of the present invention and a heater assembly, and an aerosol generating device comprising a power supply for supplying power to the heater assembly and a control circuit for controlling the power supply from the power supply to the heater assembly.

[0269] The heater assembly may be a component of the device. Therefore, the aerosol generating system may include a cartridge containing a liquid storage portion for storing a liquid aerosol forming substrate, an aerosol generating device including a heater assembly according to a first aspect of the present invention, a power supply for supplying power to the heater assembly, and a control circuit for controlling the power supply from the power supply to the heater assembly.

[0270] The cartridge may be a replaceable cartridge. The cartridge may be detachably coupled to the aerosol generator.

[0271] The cartridge may have a connecting end configured to connect the cartridge to an aerosol generator. The connecting end of the cartridge may be configured to detachably connect the cartridge to the aerosol generator. The connecting end may be located at the distal end of the cartridge.

[0272] The cartridge may include a mouthpiece positioned at the mouth end of the cartridge. The mouthpiece may include an aerosol outlet through which the generated aerosol can be drawn out by the user.

[0273] The mouth end of the cartridge faces the distal end of the cartridge.

[0274] 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.

[0275] 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 enclose an aerosol. 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.

[0276] The cartridge may include a cartridge housing. The cartridge may be formed from a durable material. The cartridge housing may be formed from a liquid-impermeable material. The cartridge housing may be made from a moldable plastic material such as polypropylene (PP) or polyethylene terephthalate (PET), or a copolymer made from three monomers: terephthalate dimethyl (DMT), cyclohexanedimethanol (CHDM), and Tritan TMIt may be formed from 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO), such as the above. The cartridge housing of the cartridge may define a part of the liquid storage portion, i.e., the storage section. The cartridge housing may define the liquid storage portion. The cartridge housing and the liquid storage portion may be formed integrally. Alternatively, the liquid storage portion may be formed separately from the cartridge housing or disposed within the cartridge housing.

[0277] The liquid storage portion of the cartridge may include a liquid aerosol-forming substrate. In other words, the cartridge may include a liquid aerosol-forming substrate stored within the liquid storage portion of the cartridge.

[0278] The liquid aerosol-forming substrate may be liquid at room temperature. The liquid aerosol-forming substrate may contain both liquid and solid components.

[0279] The liquid aerosol-forming substrate may contain nicotine. The liquid aerosol-forming substrate may have a nicotine concentration of about 0.5% to about 10%, for example, about 2%.

[0280] The liquid aerosol-forming substrate containing nicotine may also be a nicotine salt matrix.

[0281] 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 that contain 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.

[0282] The liquid aerosol forming substrate may comprise one or more aerosol formers. An aerosol former is any suitable known compound, or mixture of compounds, that facilitates the formation of a high density, stable aerosol upon use and is substantially resistant to thermal decomposition at the operating temperature of the system. Examples of suitable aerosol formers include glycerin and propylene glycol. Suitable aerosol formers are well known in the art and include polyhydric alcohols (such as triethylene glycol, 1,3 - butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate, etc.), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.), but are not limited thereto.

[0283] The liquid aerosol forming substrate may include water, solvents, ethanol, plant extracts, and natural or artificial flavors.

[0284] The liquid aerosol forming substrate may include nicotine and at least one aerosol former. The aerosol former may be glycerin or propylene glycol. The aerosol former may include both glycerin and propylene glycol.

[0285] The liquid storage portion may be disposed on the first side of the heater assembly. The airflow channel may be disposed on the side opposite the first side surface of the heater assembly. The airflow channel may be adjacent to the electrical heating element. The airflow path may extend through the electrical heating element. The airflow path may be configured to transmit the aerosol. The cartridge body may be configured such that the airflow passing through the heater assembly entrains the vaporized aerosol forming substrate.

[0286] The porous outer surface may comprise a first porous outer surface of the porous body, i.e., the aerosolization surface. The porous body may comprise a second porous outer surface, i.e., the liquid absorption surface. The second porous outer surface, i.e., the liquid absorption surface, may be located on the opposite side of the first porous outer surface. The liquid storage portion may be disposed on the same side of the heater assembly as the second porous outer surface, i.e., the liquid absorption surface.

[0287] The aerosolization cavity may be disposed on the same side of the heater assembly as the first porous outer surface, i.e., the aerosolization surface. The aerosolization cavity may receive an aerosol from the heater assembly by being in fluid communication with the first porous outer surface, i.e., the aerosolization surface. The aerosolization cavity may entrain the aerosol into the air stream by being in fluid communication with the air flow path.

[0288] The aerosol generator may comprise a housing. The housing may be elongate. The housing may comprise any suitable material or 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, polyether ether ketone (PEEK), and polyethylene. The material is preferably lightweight and non-brittle.

[0289] The housing of the aerosol generator may define a recess, i.e., a recess, for receiving a portion of the cartridge. The aerosol generator may have a connection end configured to connect the aerosol generator to the cartridge. The connection end of the aerosol generator may be configured to removably connect the aerosol generator to the cartridge. The connection end may comprise a recess, i.e., a recess, for receiving the cartridge. The connection end of the aerosol generator may be the proximal end of the aerosol generator.

[0290] The aerosol generator has a distal end opposite to its proximal end. The connection end of the aerosol generator may be located at the proximal end of the device. In other words, the aerosol generator may have a connection end opposite to its distal end.

[0291] 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.

[0292] 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.

[0293] 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.

[0294] The heating element may be fluid-permeable so that vapor is released from the heater assembly in the mean vapor discharge direction during use. The aerosol generation system may include an air intake and an aerosol outlet. The air intake may be in fluid communication with the aerosol outlet to define an airflow path through the aerosol generation system. The heater assembly may be arranged in fluid communication with the airflow path so that air flows through the heater assembly in the mean airflow direction. The heater assembly and the airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0295] As used herein, the term “angle between mean vapor discharge direction and mean airflow direction” refers to the angle between the direction of vapor movement from a 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 airflow and vapor discharge are diametrically opposed.

[0296] 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 does not decrease to the same extent as if the mean airflow direction were directly opposite to the mean vapor discharge direction. This reduces the tendency for recirculation and turbulence to occur within the airflow path, and the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Consequently, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0297] The average vapor emission direction may be substantially perpendicular to the heating surface. As used herein, the term “substantially perpendicular” means 90 degrees plus or minus 10 degrees, preferably plus or minus 5 degrees.

[0298] The advantage of a mean vapor release direction substantially perpendicular to the heated surface is that, since the vapor is released substantially perpendicular to the heated surface of the porous material, it is easy to orient the mean vapor release direction relative to the mean airflow direction. Therefore, the desired angle between the mean vapor release direction and the mean airflow direction can be achieved by appropriately angling the heater assembly with respect to the airflow in the airflow path, or vice versa.

[0299] 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.

[0300] 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 90 degrees. This arrangement ensures that the vapor is discharged at an angle substantially perpendicular to the mean airflow direction. The mean vapor discharge direction has no velocity or directional component opposite to the airflow direction, thus reducing momentum loss in the airflow. This reduces the tendency for recirculation and turbulence to occur within the airflow path, and the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Furthermore, vapor mixing into the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0301] 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. Therefore, any loss of momentum in the airflow is further reduced. This reduces the tendency for recirculation and turbulence to occur in the airflow path, and the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Furthermore, the mixing of vapor into the airflow is improved. Therefore, the likelihood of aerosol condensation occurring in the aerosol generating system is low.

[0302] 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.

[0303] 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 the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Furthermore, vapor mixing in the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0304] 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.

[0305] The heating element may comprise a porous layer of conductive material. Advantageously, a heating element comprising a porous layer of conductive material allows for resistance heating and also allows electric current to flow through the heating element, enabling vapor to move through the pores within its porous structure. Therefore, vapor release occurs through the porous heating element. This avoids the accumulation of vapor pressure beneath the heating element and high-speed vapor release at the sides of the heating element. The inventors found that this arrangement generates consistent vapor across the heating element with a lower vapor release rate of approximately 0.1 meters / second. Such a low vapor release rate means that the vapor is easily carried by an airflow that reduces vapor collisions on the inner walls of the aerosol generating system.

[0306] 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 configured to perform multiple cycles of charging and discharging. The power source may have a capacity that allows for sufficient energy storage for one or more user experiences of the aerosol generation system. For example, the power source may have a capacity sufficient to allow for continuous generation of aerosol for about six minutes, or a multiple of six minutes, corresponding to the typical time taken to smoke a conventional cigarette. In another embodiment, the power source may have a sufficient capacity to allow for a predetermined number of smoking sessions or to allow for intermittent activation of the aerosol generation system.

[0307] The control circuit may comprise any suitable controller or electrical component. The controller may include a memory. Information for implementing the above-described method may be stored in the memory. The control circuit may comprise a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, or an application-specific integrated circuit (ASIC) or other electronic circuit having the ability to provide control. The control circuit may be configured to continuously supply power to the heating element after activation of the device, or may be configured to supply power intermittently, such as for each puff. The power may be supplied to the heating element in the form of current pulses, for example, by pulse width modulation (PWM).

[0308] The control circuit may further comprise additional electronic components. For example, in some embodiments, the control circuit may comprise any of a sensor, a switch, or a display element.

[0309] 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.

[0310] 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, or forms, or aspects described herein.

[0311] Example 1: A heater assembly for an aerosol generating 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 includes a liquid absorption surface and a heating surface, and the heating element is located on the heating surface of the porous body. Example 2: The heater assembly according to Example 1, wherein the porous body includes a porous ceramic body or a porous glass body. Example 3: The heater assembly according to Example 1 or 2, wherein the heating surface of the porous body is convex in 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 4: A heater assembly according to any one of Examples 1 to 3, wherein the porous body includes one or more symmetrical planes in the direction of the long axis. Example 5: A heater assembly according to any one of Examples 1 to 4, wherein the heating surface of the porous body has a radius of curvature of at least about 1.5 millimeters in one or both of the first transverse direction and the second transverse direction. Example 6: A heater assembly according to any one of Examples 1 to 5, wherein the heating surface of the porous body has a radius of curvature of about 10 millimeters or less in one or both of the first transverse direction and the second transverse direction. Example 7: A heater assembly according to any one of Examples 1 to 6, wherein the ratio of the radius of curvature of the heated surface to the width of the heated surface in the same transverse direction is at least about 0.5. Example 8: A heater assembly according to any one of Examples 1 to 7, wherein the ratio of the radius of curvature of the heated surface to the width of the heated surface in the same transverse direction is approximately 5 or less. Example 9: A heater assembly according to any one of Examples 1 to 8, wherein the width of the heated surface is less than or substantially equal to the width of the porous body in the same transverse direction. Example 10: A heater assembly according to any one of Examples 1 to 9, wherein the width of the heated surface is greater than the width of the porous body in the same transverse direction. Example 11: A heater assembly according to any one of Examples 1 to 10, wherein the width of the heated surface in one or both of the first and second transverse directions is at least about 0.5 millimeters. Example 12: A heater assembly according to any one of Examples 1 to 11, wherein the width of the heated surface in one or both of the first transverse direction and the second transverse direction is approximately 12 millimeters or less. Example 13: A heater assembly according to any one of Examples 1 to 12, wherein the heating surface of the porous material has a length of at least about 0.5 millimeters. Example 14: A heater assembly according to any one of Examples 1 to 13, wherein the heating surface of the porous material has a length of less than approximately 6 millimeters. Example 15: A heater assembly according to any one of Examples 1 to 14, wherein the width of the heating surface is greater than the length of the heating surface in one or both of the first and second transverse directions. Example 16: A heater assembly according to any one of Examples 1 to 15, wherein the ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions is at least about 0.02. Example 17: A heater assembly according to any one of Examples 1 to 16, wherein the ratio of the length of the heated surface to the width of the heated surface in one or both of the first and second transverse directions is approximately 0.5 or less. Example 18: A heater assembly according to any one of Examples 1 to 17, wherein the ratio of the length of the heating surface to the length of the porous body is at least about 0.05. Example 19: A heater assembly according to any one of Examples 1 to 18, wherein the ratio of the length of the heated surface to the length of the porous body is approximately 0.45 or less. Example 20: A heater assembly according to any one of Examples 1 to 19, wherein the liquid-absorbing surface of the porous material has a different area from the heating surface of the porous material. Example 21: A heater assembly according to any one of Examples 1 to 20, wherein the width of the heating surface of the porous material is less than the width of the liquid-absorbing surface of the porous material in the same transverse direction. Example 22: A heater assembly according to any one of Examples 1 to 21, wherein the porous body has a shape that tapers from the liquid-absorbing surface of the porous body toward the heating surface of the porous body. Example 23: A heater assembly according to any one of Examples 1 to 22, wherein the porous body has a shape that tapers from the heating surface of the porous body toward the liquid-absorbing surface of the porous body. Example 24: A heater assembly according to any one of Examples 1 to 23, wherein the average pore size of the porous material changes between the liquid absorption surface and the heating surface. Example 25: A heater assembly according to any one of Examples 1 to 24, wherein the heating element includes multiple tracks or track sections electrically arranged in parallel. Example 26: A heater assembly according to any one of Examples 1 to 25, wherein the heating element includes a plurality of tracks or track portions that define a path having at least one bend, and the inner edge of the bend is curved. Example 27: A heater assembly according to any one of Examples 1 to 26, wherein the heating element is convex in one or both of the first transverse direction and the second transverse direction. Example 28: A heater assembly according to any one of Examples 1 to 27, wherein the porous body and the heating element are formed as two separate parts assembled together. Example 29: A heater assembly according to any one of Examples 1 to 28, wherein the porous body and the heating element are integrally formed. Example 30: A heater assembly according to any one of Examples 1 to 29, wherein the heating element is a doped portion of a porous material. Example 31: A heater assembly according to any one of Examples 1 to 30, wherein the heater assembly comprises an insulating layer having a lower thermal conductivity than the porous body, the insulating layer is placed between the porous body and the heating element, and the insulating layer is configured to reduce heat transfer from the heating element to the porous body. Example 32: A heater assembly according to any one of Examples 1 to 31, wherein the heating element is fluid permeable. Example 32: An aerosol generating system comprising a heater assembly described in any one of Examples 1 to 31, a cartridge including a liquid storage portion for storing a liquid aerosol forming substrate, and an aerosol generator including a power supply for supplying power to the heater assembly and a control circuit for controlling the power supply from the power supply to the heater assembly, wherein the heater assembly is a component of either the cartridge or the aerosol generator. Example 33: The aerosol generating system according to Example 32, wherein the heating element is fluid permeable so that vapor is released from the heater assembly in the mean vapor discharge direction during use, the aerosol generating system further comprises an air intake and an aerosol outlet to define an airflow path through the aerosol generating system, the heater assembly is 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 are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0312] The present invention will be further described with reference to the attached drawings, for illustrative purposes only.

[0313] Figure 1 shows a heater assembly 100 for use in an aerosol generation system. The heater assembly 100 comprises a heating element 110 for vaporizing a liquid aerosol-forming substrate. The heater assembly 100 also comprises a porous body 120 for transporting the liquid aerosol-forming substrate to the heating element 110. The porous body 120 has a liquid-absorbing surface 121 and an opposing heating surface 122. The heating element 110 is located on the heating surface 122 of the porous body 120.

[0314] The heated surface 122 of the porous body 120 is curved. In particular, the heated surface 122 of the porous body 120 is curved in a convex shape in a single transverse direction (first transverse direction).

[0315] The porous material may be a porous ceramic body or a porous glass body.

[0316] The porous body 120 has a prismatic shape. When viewing a cross-section of the porous body 120 in the direction of its major axis perpendicular to the curvature direction, the heated surface 122 of the porous body 120 is shown as a circular arc. The porous body 120 has two symmetrical planes in the direction of its major axis.

[0317] The heating surface 122 of the porous body 120 has a first transverse width 123 that is substantially the same as the width of the porous body 120 in the first transverse direction and substantially the same as the width of the heater assembly 100 in the first transverse direction. The heating surface 122 of the porous body 120 has a width of about 5 millimeters in the first transverse direction.

[0318] The heated surface 122 of the porous body 120 has a length or thickness 124 of approximately 1 millimeter. The porous body 120 has a length or thickness 125 of approximately 3 millimeters.

[0319] The heated surface 122 of the porous material has a radius of curvature of approximately 3.6 millimeters. The heated surface 122 of the porous material has a surface area of ​​approximately 28 square millimeters.

[0320] The porous body 120 includes four longitudinal surfaces or sidewalls extending from the liquid-absorbing surface 121 to the heating surface 122. The four sidewalls are substantially perpendicular to the liquid-absorbing surface 121, which is substantially flat. The liquid-absorbing surface 121 has a square shape.

[0321] The heating element 110 is a resistance heating element 110.

[0322] The heating element 110 is curved. In particular, the curvature of the heating element is substantially the same as the curvature of the heating surface 122 of the porous body 120. Thus, the heating element 110 is also convex in a single transverse direction.

[0323] The heating element 110 is located directly on the heating surface 122 of the porous body 120. The heating element 110 extends over most of the heating surface 122 of the porous body 120. Substantially the entire heating element 110 is in contact with the heating surface 122 of the porous body 120.

[0324] In the embodiment shown in Figure 1, the pore diameter of the porous body 120 is the same between the liquid absorption surface 121 and the heating surface 122.

[0325] In another embodiment, the pore diameter of the pores within the porous body 120 varies between the liquid absorption surface 121 and the heating surface 122.

[0326] The porous body 120 may include a heating end and a liquid absorption end, with the heating surface 122 located at the heating end and the liquid absorption surface 121 located at the liquid absorption end. The porous body 120 may include 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.

[0327] In this alternative embodiment, the first average pore diameter at the liquid absorption end is approximately 150 micrometers. The second average pore diameter at the heating end is approximately 20 micrometers. The pore diameter changes linearly between the first and second average pore diameters, providing a pore diameter gradient between the liquid absorption and heating ends of the porous body 120.

[0328] The pore structure and pore diameter gradient of the porous body 120 are achieved by etching pores into a portion of the porous body 120.

[0329] Figure 2A shows a schematic side view of a heater assembly 200 for use in an aerosol generation system, which is according to a first embodiment of the present invention.

[0330] Similar to the heater assembly 100 shown in Figure 1, the heater assembly 200 shown in Figure 2A comprises a heating element 210 for vaporizing a liquid aerosol-forming substrate and a porous body 220 for transporting the liquid aerosol-forming substrate to the heating element 210. The porous body 220 has a liquid-absorbing surface 221 and an opposing heating surface 222. The heating element 210 is located on the heating surface 222 of the porous body 220.

[0331] The heated surface 222 of the porous body 220 is curved. In particular, the heated surface 222 of the porous body 220 is curved in a convex manner in two transverse directions. The heated surface 222 of the porous body 220 is convex in both the first transverse direction and the second transverse direction.

[0332] The heated surface 222 of the porous body 220 has substantially the same shape as the surface of the spherical cap or spherical dome. The porous body 220 is substantially radially symmetrical.

[0333] The porous body 220 includes a surface or sidewall in the long axis direction extending from the liquid absorption surface 221 to the heating surface 222. The sidewall is substantially perpendicular to the liquid absorption surface 221, which is substantially flat. The liquid absorption surface 221 has a substantially circular shape.

[0334] The heating element 210 is a resistance heating element 210.

[0335] The heating element 210 is curved. In particular, the curvature of the heating element 210 is substantially the same as the curvature of the heating surface 222 of the porous body 220. Thus, the heating element 210 is also convex in both the first transverse direction and the second transverse direction.

[0336] The heating element 210 is located directly on the heating surface 222 of the porous body 220. The heating element 210 extends over most of the heating surface 222 of the porous body 220. Substantially the entire heating element 210 is in contact with the heating surface 222 of the porous body 220.

[0337] The heating element 210 has a spiral shape.

[0338] Figure 2B shows the porous body 220 of the heater assembly 200. The heating element 210 of the heater assembly 200 is not shown in Figure 2B.

[0339] A portion of the edge of the heated surface 222, which is not visible in the schematic side view shown in Figure 2A, is illustrated by the dotted line in Figure 2B.

[0340] The heating surface 220 of the porous body 220 has a width 223 that is substantially the same as the width of the porous body 220 and substantially the same as the width of the heater assembly 200. As shown in Figure 2B, the heating surface 200 of the porous body 220 has a width 223 of about 5 millimeters. Therefore, the diameter of the liquid absorption surface 221 is about 5 millimeters.

[0341] The heated surface 220 of the porous body 120 has a length or thickness 124 of approximately 2 millimeters. The porous body 220 has a length or thickness 225 of approximately 7 millimeters.

[0342] The heated surface 220 of the porous material has a radius of curvature of approximately 2.6 millimeters in both the first transverse direction and the second transverse direction.

[0343] Figure 3 shows a heater assembly 300 for use in an aerosol generating system, which is according to a first aspect of the present invention. The heater assembly 300 shown in Figure 3 has a substantially similar structure to the heater assembly 100 shown in Figure 1. Similar reference numerals are used in Figures 1 to 3 to specify similar parts.

[0344] The heating surface 122 of the heater assembly 300 shown in Figure 3 is the same as the heating surface 122 of the heater assembly 100 shown in Figure 1.

[0345] The heater assembly 300 shown in Figure 3 differs from the heater assembly 100 shown in Figure 1 in that the width 323 of the liquid absorption surface 321 in the first transverse direction is less than the width 123 of the heating surface 122 in the first transverse direction. The width 123 of the heating surface 122 in the first transverse direction corresponds to the width of the porous body 320 of the heater assembly 300 in the first transverse direction.

[0346] The width of the liquid-absorbing surface 321 in the second transverse direction is substantially the same as the width of the heating surface 122 in the second transverse direction, and the second transverse direction is perpendicular to the first transverse direction.

[0347] The porous body 320 has a prismatic shape.

[0348] The liquid absorption surface 321 is substantially flat and rectangular in shape. The liquid absorption surface 321 has an area less than the surface area of ​​the heating surface 122.

[0349] The porous body 320 includes four side walls extending from the liquid-absorbing surface 321 to the heating surface 122. Two of the side walls are substantially perpendicular to the liquid-absorbing surface 321. The other two side walls have a rectangular shape and are angled relative to the liquid-absorbing surface 321.

[0350] Figure 4 shows a heater assembly 400 for use in an aerosol generating system, which is according to a first aspect of the present invention. The heater assembly 400 shown in Figure 4 has a substantially similar structure to the heater assembly 100 shown in Figure 1. Similar reference numerals are used in Figures 1 to 4 to specify similar parts.

[0351] The heating surface 122 of the heater assembly 400 shown in Figure 4 is the same as the heating surface 122 of the heater assembly 100 shown in Figure 1.

[0352] The heater assembly 400 shown in Figure 4 differs from the heater assembly 100 shown in Figure 1 in that the width 423 of the liquid absorption surface 421 in the first transverse direction is greater than the width 123 of the heating surface 122 in the first transverse direction. The width 423 of the liquid absorption surface 421 in the first transverse direction corresponds to the width of the porous body 420 of the heater assembly 400.

[0353] The width of the liquid-absorbing surface 421 in the second transverse direction is substantially the same as the width of the heating surface 122 in the second transverse direction, and the second transverse direction is perpendicular to the first transverse direction.

[0354] The porous body 420 has a prismatic shape.

[0355] The liquid absorption surface 421 is substantially flat and rectangular in shape. The liquid absorption surface 421 has a larger surface area than the heating surface 122.

[0356] The porous body 420 includes four side walls extending from the liquid-absorbing surface 421 to the heating surface 122. Two of the side walls are substantially perpendicular to the liquid-absorbing surface 421. The other two side walls have a rectangular shape and are angled relative to the liquid-absorbing surface 421.

[0357] The porous body 420 tapers from the liquid absorption surface 421 towards the heating surface 122. The cross-sectional area of ​​the porous body 420 gradually decreases from the liquid absorption surface 421 towards the heating surface 122.

[0358] Figure 5 shows a heater assembly 500 for use in an aerosol generating system, which is according to a first aspect of the present invention. The heater assembly 500 shown in Figure 5 is substantially similar in structure to the heater assembly 100 shown in Figure 1. Similar reference numerals are used in Figures 1 and 5 to specify similar parts.

[0359] The porous body 120 shown in Figure 5 is the same as the porous body 120 shown in Figure 1.

[0360] The heater assembly 500 shown in Figure 5 differs from the heater assembly 100 shown in Figure 1 in that the heater assembly 500 includes an insulating layer 530 located between the porous body 120 and the heating element 110. The insulating layer 530 is in direct contact with both the heating surface 122 of the porous body 120 and the heating element 110. The insulating layer 120 substantially covers the entire heating surface 122 of the porous body 120.

[0361] The insulation layer 530 is arranged to enhance the insulation between the heating element 110 and the porous body 120. The insulation layer 530 is configured to reduce heat dissipation through the porous body 120 in order to improve the energy efficiency of the heater assembly 500 by reducing energy loss.

[0362] The insulation layer 530 is curved. In particular, the insulation layer 530 is convexly curved in a single transverse direction (first transverse direction). The curvature of the insulation layer 530 corresponds to the curvature of the heated surface 122 of the porous body 120.

[0363] In particular, the thermal insulation layer 520 has a first end face and an opposing second end face. The first end face is a liquid absorption surface 531, and the second end face is a heating surface 532. Both the liquid absorption surface 531 of the thermal insulation layer 530 and the heating surface 532 of the thermal insulation layer are convex in the first transverse direction, and their curvature corresponds to the curvature of the heating surface 122 of the porous body 120.

[0364] The liquid-absorbing surface 531 of the insulating layer is in direct contact with the heating surface 122 of the porous body.

[0365] The thermal insulation layer 530 has a thickness defined between its liquid absorption surface 531 and its heating surface 532. The thickness of the thermal insulation layer 530 is less than the thickness of the porous body 120. The thermal insulation layer may have a thickness of about 0.1 mm to about 2 mm, preferably about 0.5 mm to about 1.5 mm.

[0366] The thermal insulation layer 530 contains a material having a low thermal conductivity. The thermal insulation layer 530 contains, or consists of, a material having a lower thermal conductivity than the porous body 120. The thermal insulation layer 530 may have a higher porosity than the porous body 120. The thermal insulation layer 530 may contain one or more materials such as alumina, zirconia, zirconia with magnesium oxide, glass ceramic, quartz, and porous polymers. It will be understood that the thermal insulation layer 530 may have different shapes or contain different materials.

[0367] Referring to Figures 6A to 6C, schematic diagrams of different heating element 610 embodiments for an aerosol generation system are shown. Each heating element 610 includes multiple tracks or track sections 617 arranged electrically in parallel. By being arranged electrically in parallel, the current flow is divided into separate parallel channels. The channels are then recombined.

[0368] In the heating elements 610 of Figures 6A to 6C, each heating element 610 includes a first connection pad 613 and a second connection pad 614. The first and second connection pads 613 and 614 are configured to allow connection to an external circuit. An opening or a number of openings 615 within the heating element 610 isolates each track 617. Each heating element 160 includes a branching section where the current is split from the first connection pad 613 to the tracks 617 which define electrically parallel paths. Each heating element 610 includes a converging section that integrates the current from the tracks 617 which define electrically parallel paths and leads into the second connection pad 614.

[0369] Various different arrangements of electrically parallel tracks or track sections are possible. In Figure 6A, four tracks 617 are separated by three openings 615 to define four electrically parallel paths. In Figure 6B, six track sections 617 are separated by one opening 615 to define two electrically parallel paths. In Figure 6B, each electrically parallel path defines a meandering path between a first connection pad 613 and a second connection pad 614. In Figure 6C, eight track sections 617 are separated by four openings 615 to define four pairs of electrically parallel paths. Each pair of electrically parallel paths in Figure 6C is separated by an intermediate connection 616, three of which are shown in Figure 6C.

[0370] By electrically arranging tracks or track sections in parallel, if one track section is faulty, the current can be redistributed and still flow through the heating element 610, i.e., the electrical connection between the first connecting pad 613 and the second connecting pad 614 is not damaged. This has the advantage of increasing the number of fume extractions before the heater completely fails, potentially extending the heater's lifespan to the lifespan of the device. In contrast, in a simple meandering heater that defines a single electrical path between the first connecting pad 613 and the second connecting pad 614, if a part of the meandering heating element is damaged, the heating element will stop working due to the increased local resistance at the point of failure or fault. A defect in a simple meandering heater causes an increase in local resistance. An increase in local resistance causes an increase in power loss. The increase in power loss then increases the resistance until failure occurs.

[0371] The inventors also identified that electrically parallel-arranged parallel tracks or track sections, as described with reference to Figures 6A–6C, have a surprising additional advantage. In such arrangements, if one track section fails, the heating element 610 can still operate and, for an initial transient period, operate in a favorable manner because 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 throughput is increased over a smaller area. Such failures may cause an increase in current on the undamaged tracks or track sections, ultimately degrading the user experience, but the device or cartridge can incorporate a mechanism to warn the user of the potential future performance degradation of the heater assembly.

[0372] These mechanisms depend on the following principles. The total electrical resistance of the heating element depends on the following factors: 1) The number of parallel heating tracks (the more parallel tracks there are, the lower the total resistance), 2) Cross-sectional area (width or thickness (or width and thickness)) of parallel heating tracks (the larger the cross-sectional area, the lower the resistance), 3) The length of the parallel heating tracks (the longer the track, the greater the resistance), 4) If the heating element is porous, adjust the porosity of the heating element (the higher the porosity, the greater the resistance). 5) A specific chemical or material composition (e.g., a doped alloy).

[0373] The overall total heating resistance R of a configuration of many heating tracks or track sections (i) arranged in parallel such that the current flows in the same direction in at least two adjacent tracks or track sections. tot , R i This is shown in Equation 1,

number

[0374] The behavior of the parallel track heating element 610 when one heating track fails can be considered, for example, by referring to a heating element having four parallel heating tracks, as shown in Figure 6A. Each heating track has a resistance of 3 ohms. The total resistance of the heating element is 0.75 ohms, which is calculated using Equation 1.

[0375] When one heating track begins to fail, the resistance of the failed heating track increases. The total resistance of the heating element 610 also begins to increase according to a linear relationship with the resistance of the defective heating track. However, as the heating track resistance continues to increase, the heating element resistance asymptotically approaches a constant resistance value. At this constant resistance value, the effect of the defective heating track on the heating element resistance is limited. In this embodiment, where each undamaged heating track has a resistance of 3 ohms, if the failed track can be considered an open circuit (i.e., no further current flows through it), the total resistance of the heating element asymptotically approaches 1 ohm. In this embodiment, if one track fails, only three tracks remain for the purpose of calculating the total resistance of the heating element.

[0376] To account for the behavior of these heating elements 610, a supply voltage of 3.5 volts and a target power of 5.5 watts are considered. In this embodiment, the undamaged parallel heating tracks remain at an initial resistance of 3 ohms. In the faulty track, the total maximum current decreases as the resistance increases. In the faulty track, the current decreases to zero upon failure. Even as the resistance of the faulty track increases, the current through the undamaged parallel tracks remains substantially constant (ignoring resistance changes due to temperature rise).

[0377] Similar behavior is observed for maximum power generation. When a heating track fails, the total power generated decreases. However, in this embodiment, despite the failure of one of the heating tracks, the maximum power remains above the target of 5.5 watts.

[0378] In contrast to porous heater films, the increase in the overall heating resistance of parallel track heating elements can be monitored by control electronics. In heater films, the current density (perpendicular to the flow of current) at both ends of the heater film increases in the damaged area, generating more power and raising the local temperature, so the damaged area can expand over time until failure occurs. This locally increases the resistance of the heater film, causing the temperature to rise further until it breaks (i.e., positive feedback). In parallel track heating elements 610, in contrast, the increase in the overall heating resistance can be monitored by control electronics. The device or system may be configured to communicate to the user through a user interface that the device or system should replace the heater assembly when a predetermined threshold is reached.

[0379] An aerosol generator or system may include a control circuit. The control circuit may be configured to adjust the power supplied to the heater after detecting a failure in a heating track, for example, by a feedback loop. The control circuit may be configured to control the power supplied to the heater by providing a pulse-width modulation ("PWM") signal. The control circuit may adjust the power supplied to the heater by adjusting the load cycle of the pulse-width modulation signal. In one embodiment, the control circuit may be configured to have a load cycle of 33.7 percent when the heating tracks are in normal condition. The load cycle may increase to 44.9 percent when one of the heating tracks fails. When one of the heating tracks fails, the power density (heating power generated by the surface area) increases, and the thermal efficiency of the heater body is enhanced. Thus, the proper operation of the heater is not jeopardized by one failed heating track. A similar result occurs when a second heating track fails. The control circuit may be configured to further increase the load cycle (up to 67.4 percent in the current embodiment). Therefore, a heating element with four parallel heating tracks can still operate under nominal conditions of 5.5 watts, even if two of these heating tracks fail, because the load cycle remains below 100 percent.

[0380] The control circuit may be configured to evaluate the condition of the heating element (i.e., the number of failed heating tracks) based on the change in the nominal total resistance of the heating element 610 when a parallel heating track fails. The control circuit may also be configured to inform the user that the device should replace the heater assembly after a predetermined number of heating tracks have failed.

[0381] Referring to Figures 7A and 7B, schematic diagrams of the current flow 709 around the corners of the heating element track are shown.

[0382] Figure 7A is a schematic diagram of current flow 709 around a known heating element, where the track portion defines a path with bends, 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 arrow 709 following the path of least resistance. This concentration occurs at the inner edge of the corner. The current concentration can raise the local temperature, potentially causing 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 increases due to the local rise in temperature (this causes the current to flow through the path of lower resistance).

[0383] Figure 7B is a schematic diagram of the current flow 709 around a heating element, where the track portion 717 defines a path with bends, and the inner edge of the bends is curved. In such a track 717, the current flow 709 does not form localized hot spots.

[0384] In contrast to the track shape shown in Figure 7A, the current flow 709 in a smoother, curved section of the track 717, as shown in Figure 7B, remains more evenly distributed across the heating track 717, as indicated by the dashed arrow 709. The current flow 709 is induced to flow more evenly, avoiding current concentration at any given point. This limits the formation of hot spots. The heater track 717 may have a resistivity gradient perpendicular to the current flow at one or more corners, such that the resistivity is higher in the inner part of the corner and lower in the outer part of the corner. Such gradients are beneficial in offsetting localized high current densities and reducing the formation of hot spots.

[0385] Referring to Figure 8A, a heater assembly 800 is shown, which comprises a heating element 804 for vaporizing a liquid aerosol-forming substrate and a porous body 802 for supplying the liquid aerosol-forming substrate from a storage section or liquid storage section (not shown) to the heating element 808. The porous body 802 has a liquid absorption surface (not shown) and a heating surface 802a. The heating element 804 is disposed on the heating surface 802a of the porous body 802.

[0386] The heating element 804 is formed from a layer of conductive material so that an electric current can pass through it and heat it by resistance heating or Joule heating. The heating element 804 is also fluid permeable and porous so that vapor can pass through it from the heating surface 802a of the porous body 802. Thus, in the heater assembly 800 of Figure 8A, vapor emission occurs through the heating element 804. The heating element 804 may include a thin metal layer or film having pores that pass through the thickness of the layer or film. Alternatively, the heating element may include a metal foam having interconnected open pores that pass through the thickness of the foam. In this embodiment, the porous body 802 includes a porous ceramic body formed from a suitable ceramic material such as Al2O3. Furthermore, the heating element 804 is deposited on the porous ceramic body 802 using a suitable physical or chemical vapor deposition process.

[0387] The heater assembly 800 further comprises electrical contacts 806 electrically connected to the heating element 804. The electrical contacts 806 are located on and at or near both ends of the heating surface 802a. The heating element 804 may extend between the electrical contacts 806. The electrical contacts 806 are arranged to be connected to a control circuit for controlling the power supply to the heating element. The electrical contacts 806 are formed from a material with higher conductivity than the heating element, such as copper, gold, or zinc, but other suitable materials may be used. This prevents the generation of excess waste heat within the electrical contacts.

[0388] Figure 8B shows a schematic cross-sectional view of the heater assembly 800 of Figure 8A. For clarity and simplification, the electrical contacts 806 from Figure 8A are omitted in Figure 8B, and features are not drawn to scale. The liquid absorption surface 802b is shown as the lower surface of the porous body 802 in Figure 8B, and the heating surface 802a is shown as the upper surface of the porous body 802, but it will be understood that the orientation of these surfaces may differ during use or after the heater assembly 800 is installed in the aerosol generator. Liquid stored in the liquid storage section or liquid storage portion (not shown) comes into contact with the liquid absorption surface 802b and is transported through the porous body 802 to the heating surface 802a, as indicated by arrow E in Figure 8B. The porous heating element 804 is positioned on the heating surface 802a of the porous body 802 and heats the transported liquid aerosol-forming substrate so that the liquid aerosol-forming substrate boils and generates steam. The porous heating element 804 has a plurality of pores 808 that extend from the heating surface 802a to the outside of the heater assembly 800, passing through the thickness of the heating element.

[0389] Because the heating element 804 is porous, steam generated during heating of the heating element 804 can pass through the heating element 804 via the pores 108, as indicated by arrow F in Figure 8B, and be radiated from the heating surface 802a. The heating element does not have an impermeable section to prevent steam release and cause steam pressure to build up beneath the heating element. This reduces the rate of steam release from the heating element 804 compared to conventional impermeable track heating elements. Simulations demonstrated that the average steam release rate from the heating surface 802a is 0.1 meters / second at a power of 6.3 watts. Such a low steam release rate means that the steam can be easily carried by the airflow within the airflow path without colliding with the inner walls of the airflow path and causing condensation. The average steam release direction is substantially perpendicular to the liquid absorption surface 802b of the porous body 802, which is substantially flat.

[0390] Figure 9 is a schematic diagram of the interior of an aerosol generating system 900 according to an embodiment of a second aspect of the present invention. The aerosol generating system comprises two main components, namely a cartridge 902 and a main body or aerosol generating device 904. The connection end 902a of the cartridge 902 is detachably connected to the corresponding connection end 904a of the aerosol generating device 904. The connection end 902a of the cartridge 902 and the connection end 904a of the aerosol generating device 904 each have electrical contacts or connections (not shown) arranged to cooperate to provide an electrical connection between the cartridge 902 and the aerosol generating device 904. In this embodiment, the aerosol generating device 904 comprises a power source in the form of a battery 906, which is a rechargeable lithium-ion battery, and a device housing 909 that houses a control circuit 908. The aerosol generating system 900 is portable and has a size comparable to a conventional cigar or cigarette. A mouthpiece 910 is disposed at the mouth end 902b of the cartridge 902. The mouth end 902b is located on the opposite side from the connection end 902a of the cartridge 902.

[0391] The cartridge 202 comprises a heater assembly 800 and a cartridge housing 912 that houses a liquid storage section or liquid storage portion 918 for holding a liquid aerosol-forming substrate. The heater assembly 800 in Figure 9 has a structure similar to that of Figures 8A and 8B, but its orientation is reversed compared to that in Figures 8A and 8B, with the liquid absorption surface 802a facing upward and in fluid communication with the liquid storage portion 818, and the heating surface 802a carrying a heating element (not shown) facing downward. The liquid aerosol-forming substrate is carried downward from the liquid absorption surface 802b through the porous body 802 to the heating element, and when power is supplied to the heating element, the vaporized aerosol-forming substrate is released from the heating surface 802a. As indicated by arrow F in Figure 8B, the mean vapor release direction is substantially perpendicular to the liquid absorption surface 802b of the porous body 802.

[0392] The cartridge 902 includes one or more air intakes 922 formed within the cartridge housing 912 at positions along the length of the cartridge 902 corresponding to the position of the heated surface 802a of the heater assembly 800. The aerosol outlet 926 is located within the mouthpiece 910 at the mouth end 902b of the cartridge 902. The one or more air intakes 922 are in fluid communication with the aerosol outlet 926 to define an airflow path 920 through the cartridge 902 of the aerosol generating system 900. The airflow path 920 flows from the one or more air intakes 922 to the heater assembly 800 in the airflow channel 923. The heater assembly 900 is arranged to be in fluid communication with the airflow path 920 in the airflow channel 923. Air enters the one or more air intakes 922 and flows through the airflow channel 923 and through the heater assembly 800 in the mean airflow direction, as indicated by arrow I in Figure 9. As shown in Figure 9, the heater assembly 800 and the airflow path 920 within the airflow channel 923 are arranged such that the angle between the mean steam discharge direction F and the mean airflow direction I is approximately 90 degrees, i.e., substantially perpendicular to the mean airflow direction I. The mean steam discharge direction F has no velocity or directional component opposite to the mean airflow direction I, and therefore the loss of steam momentum is reduced. This reduces the tendency for steam recirculation and turbulence within the airflow path 920, and the steam is less likely to collide with the inner surface of the airflow channel 923.

[0393] In the embodiment shown in Figure 9, the liquid storage section 918 is arranged around a centrally sealed aerosol channel 924, which has an annular cross-section. When the airflow path 920 reaches the heater assembly 800, it is redirected upwards around the side of the heater assembly 800 and flows through the aerosol channel 924 to the aerosol outlet 926. Naturally, other arrangements of the liquid storage section and airflow path can be implemented, such as those discussed below with respect to Figures 10 and 11.

[0394] The aerosol generating system 900 is configured such that a user can inhale or smoke the mouthpiece 910 of the cartridge 902, thereby drawing an aerosol into their mouth through the aerosol outlet 926. During operation, when a user smokes the mouthpiece 910, air is drawn in through one or more air intake ports 922, passes through the airflow channel 923 along the airflow path 920, around the heater assembly 800, passes through the aerosol channel 924 along the airflow path 920, and is drawn out to the aerosol outlet 926. The control circuit 908 controls the supply of power from the battery 906 to the cartridge 902 when the system is started. This then controls the amount and characteristics of the vapor produced by the heater assembly 800. The control circuit 908 may include an airflow sensor (not shown), and the control circuit 920 may supply power to the heater assembly 800 when user inhalation is detected by the airflow sensor. This type of control device is well established in aerosol generating systems such as inhalers and e-cigarettes. When the user inhales vapor through the mouthpiece 910 of cartridge 902, the heater assembly 800 is activated, generating vapor that is carried along the airflow path 920. The vapor is cooled within the airflow path 920 to form an aerosol, which is then drawn into the user's mouth through the aerosol outlet 926.

[0395] Figure 10 is a schematic cross-sectional view of a portion of an aerosol generating system 1000 according to another embodiment of a second aspect of the present invention, showing the relative arrangement 800 of the heater assembly with respect to the airflow path 1020 within the aerosol generating system 1000. For simplification, other components of the aerosol generating system are omitted from Figure 10. The heater assembly 800 in Figure 10 is identical to the heater assembly 800 in Figures 8A and 8B. The aerosol generating system 1000 includes a liquid storage portion 1022 that holds a liquid aerosol-forming substrate in contact with the liquid-absorbing surface 802b of a porous body 802. The liquid aerosol-forming substrate is transported from the liquid storage portion 1022 through the porous body 802 to the heated surface 802a, as indicated by arrow E. The vaporized aerosol-forming substrate is released from the heated surface 802a through a porous heating element 804. As indicated by arrow F, the average vapor emission direction is substantially perpendicular to the liquid-absorbing surface 802b of the porous body 802.

[0396] In the embodiment shown in Figure 10, the heater assembly 800 is positioned below or to the side of one side of the airflow channel or path 1020, which is defined by the airflow channel wall 1024. As seen in Figure 10, the left end of the visible portion of the airflow path 1020 receives airflow from an air intake (not shown), and the right end of the visible portion of the airflow path delivers airflow to an aerosol outlet (not shown). The liquid-absorbing surface 802b of the porous body 802 is positioned parallel to the airflow path 1020. The heating surface 802a of the porous body faces the airflow path 1020. The heater assembly 800 is in fluid communication with the airflow path, as indicated by arrow G, such that the airflow in the airflow path flows through the heater assembly 800 in the mean airflow direction. The heater assembly 800 and the airflow path 1020 are arranged such that the angle θ between the mean vapor discharge direction F and the mean airflow direction G is approximately 90 degrees, that is, an angle θ substantially perpendicular to the mean airflow direction G. The mean vapor discharge direction F has no velocity or directional component opposite to the mean airflow direction G, and therefore the loss of momentum of the airflow is reduced. This reduces the tendency for recirculation and turbulence to occur within the airflow path 1020, and the vapor is less likely to collide with the inner surface of the airflow channel wall 1024.

[0397] Figure 11 is a schematic cross-sectional view of a portion of an aerosol generating system 1100 according to another embodiment of a second aspect of the present invention, showing another arrangement of the heater assembly 800 with respect to the airflow path 1120 within the aerosol generating system 1100. For simplification, other components of the aerosol generating system are omitted from Figure 11. The heater assembly 800 in Figure 1 is identical to the heater assembly 800 in Figures 8A and 8B. The aerosol generating system 1100 includes a liquid storage portion 1122 that holds a liquid aerosol-forming substrate in contact with the liquid-absorbing surface 802b of the porous body 802. The liquid aerosol-forming substrate is transported from the liquid storage portion 1122 through the porous body 802 to the heated surface 802a, as indicated by arrow E. The vaporized aerosol-forming substrate is released from the heated surface 802a through a porous heating element 804. As indicated by arrow F, the average vapor emission direction is substantially perpendicular to the liquid-absorbing surface 802b of the porous body 802.

[0398] In the embodiment shown in Figure 11, the airflow channel or path 1120 is divided into first and second airflow path sections 1120a and 1120b, passing through either side of the heater assembly 800. The first airflow path section 1120a and the second airflow path section 1120b merge into a third airflow path section 1120c downstream of the heater assembly 800. The first airflow path section 1120a and the second airflow path section 1120b receive airflow from one or more air intakes (not shown), and the third airflow path section 1120c delivers airflow to an aerosol outlet (not shown). The airflow path 1120 is defined by airflow channel walls 1124. The liquid-absorbing surface 802b of the porous body 802 is positioned substantially perpendicular to the airflow path 1120. The heated surface 802a of the porous body 802 faces downstream of the airflow path 1120. The heater assembly 800 is in fluid communication with the airflow path, as indicated by arrow G, so that the airflow in the airflow path flows through the heater assembly 800 in the mean airflow direction.

[0399] The heater assembly 800 and the airflow path 1120 are arranged such that the angle θ between the mean vapor release direction F and the mean airflow direction G is less than 90 degrees. Upstream of the heated surface 802a of the porous body 802, the mean airflow direction G passing through the heater assembly 800 is substantially the same as the mean vapor release direction F. Along the airflow path 1120 corresponding to the heated surface 802a, the airflow path 1120 begins to narrow inward or taper, and at that point, the mean airflow direction G passing through the heater assembly 800 changes to an angle θ of approximately 45 degrees with respect to the mean vapor release direction F. Downstream of the heated surface 802a of the porous body 802 in the third airflow path section 1120c, the mean airflow direction G of the integrated airflow is also substantially the same as the mean vapor release direction F. It will be understood that the narrowing or taper of the airflow path 1120 may be omitted. In that case, the average airflow direction G passing through the heater assembly 800 is substantially the same as the steam discharge direction F.

[0400] The specific embodiments and examples described above are illustrative of the present invention and are not limiting. Other embodiments of the present invention may be made, and it should be understood that the specific embodiments and examples described herein are not exhaustive.

Claims

1. A heater assembly for an aerosol generating system, wherein the heater assembly is 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, a heating surface, and at least one side extending from the liquid absorption surface to the heating surface, The heating element is located on the heated surface of the porous body, The heated surface of the porous body is convex in 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. The heating surface of the porous body has a width different from the width of the liquid absorption surface in the same transverse direction. A heater assembly in which the porous body includes a porous ceramic body or a porous glass body.

2. The heater assembly according to claim 1, wherein the heating surface of the porous body has a radius of curvature of at least about 1.5 millimeters in one or both of the first transverse direction and the second transverse direction.

3. The heater assembly according to claim 1 or 2, wherein the heating surface of the porous body has a radius of curvature of about 10 millimeters or less in one or both of the first transverse direction and the second transverse direction.

4. The heater assembly according to any one of claims 1 to 3, wherein, in the same transverse direction, the ratio of the radius of curvature of the heated surface to the width of the heated surface is at least about 0.

5.

5. The heater assembly according to any one of claims 1 to 4, wherein, in the same transverse direction, the ratio of the radius of curvature of the heated surface to the width of the heated surface is approximately 5 or less.

6. The heater assembly according to any one of claims 1 to 5, wherein in one or both of the first transverse directions, the ratio of the length of the heating surface to the width of the heating surface is at least about 0.

02.

7. The heater assembly according to any one of claims 1 to 6, wherein the ratio of the length of the heating surface to the length of the porous body is at least about 0.

05.

8. The heater assembly according to any one of claims 1 to 7, wherein the ratio of the length of the heating surface to the length of the porous body is approximately 0.45 or less.

9. The heater assembly according to any one of claims 1 to 8, wherein the heating surface of the porous body has a surface area in one or both of the first transverse direction and the second transverse direction that is at least about 10 percent larger than the square of the width of the heating surface.

10. The heater assembly according to any one of claims 1 to 9, wherein the heating surface of the porous body has a surface area in one or both of the first transverse direction and the second transverse direction that is about 55 percent or less greater than the square of the width of the heating surface.

11. The heater assembly according to any one of claims 1 to 10, wherein the curvature of the heating element in the first transverse direction is substantially the same as the curvature of the heated surface of the porous body in the first transverse direction, and the curvature of the heating element in the second transverse direction is substantially the same as the curvature of the heated surface of the porous body in the second transverse direction.

12. The heater assembly according to any one of claims 1 to 11, wherein the porous body has a shape that tapers along the entire length of the porous body.

13. The heater assembly according to any one of claims 1 to 12, wherein the heating surface of the porous body has a width greater than the width of the liquid absorption surface in the same transverse direction.

14. Aerosol generation system, A heater assembly according to any one of claims 1 to 13, A cartridge including a liquid storage section for storing a liquid aerosol-forming substrate, The aerosol generator includes a power supply for supplying power to the heater assembly, and a control circuit for controlling the power supply from the power supply to the heater assembly, An aerosol generating system in which the heater assembly is a component of either the cartridge or the aerosol generating device.

15. The aerosol generating system according to claim 14, wherein the heating element is fluid permeable so that steam is released from the heater assembly in the mean steam discharge direction when in use, the aerosol generating system further comprises an air intake and an aerosol outlet, defining an airflow path through the aerosol generating system, the heater assembly is 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 are arranged such that the angle between the mean steam discharge direction and the mean airflow direction is less than 135 degrees.

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