Long heater assemblies and heating assemblies for aerosol generating systems

Abstract

To provide a heating assembly which is highly rigid and inexpensive for an aerosol generator providing a supply source of heat localized for heating an aerosol forming substrate.SOLUTION: A heating assembly includes: a heater (14) provided with a heating element (82) and a heater substrate (81); and a heater mount coupled to the heater (14). The heating element (82) is configured to heat a first part (84) at a temperature higher than a second part (86). The first part (84) is positioned on the heating area (91) of the heater substrate (81). The second part (86) is positioned on a holding area (93) of the heater substrate (81). The heater mount is fixed to the holding area (93) of the heater substrate (81). The second part (86) is longer than the first part (84), and thus the heating element (82) can go through an aerosol forming substrate positioned within an aerosol forming article.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This specification relates to a heating assembly suitable for use in an aerosol-generating device or system. In particular, the present invention relates to a heating assembly having an elongated heater suitable for insertion into an aerosol-forming substrate of a smoking article to internally heat the aerosol-forming substrate. [Background technology]

[0002] There is an increasing demand for handheld aerosol generating devices that can deliver an aerosol for inhalation by a user. One particular application is for heated smoking devices in which an aerosol-forming substrate is heated to release volatile flavor compounds without burning the aerosol-forming substrate. The released volatile compounds are carried to the user in the aerosol.

[0003] Any aerosol-generating device that operates by heating an aerosol-forming substrate must include a heating assembly. Many different types of heating assemblies have been proposed for different types of aerosol-forming substrates.

[0004] One type of heating assembly that has been proposed for heated smoking devices operates by incorporating a heater into a solid aerosol-forming substrate, such as a tobacco plug. This configuration allows for direct and efficient heating of the substrate. However, this type of heating assembly presents many technical challenges, including meeting the requirements for compactness, robustness, low manufacturing costs, sufficient operating temperature, and efficient localization of the generated heat.

[0005] Heated aerosol-generating articles containing tobacco for generating aerosols by heating rather than combustion are well known in the art. The tobacco used as part of the aerosol-forming substrate in heated aerosol-generating articles is designed to generate aerosol when heated rather than burned. Therefore, such tobacco typically contains high levels of aerosol-forming agents, such as glycerin or propylene glycol. If a user were to light the heated aerosol-generating article and smoke it as if it were a traditional cigarette, the user would not have the intended user experience. It would be desirable to produce heated aerosol-generating articles with low flame ignition tendency. Preferably, such heated aerosol-generating articles are difficult to ignite when attempting to light the article with a lighter (e.g., a flame) in the manner of a traditional cigarette. One way to form a heated aerosol-generating article with low ignition tendency can be to place a tube at the distal end of the article to protect the aerosol-forming substrate from direct contact with a flame.

[0006] It would be desirable to provide a robust, inexpensive heating assembly for an aerosol-generating device that provides a localized heat source for heating an aerosol-forming substrate. It would be desirable to provide a heating assembly that is more suitable for use with an aerosol-generating article that has a non-consumable element located at the distal end of the article (e.g., a hollow tube). Summary of the Invention

[0007] In a first aspect of the present invention, there is provided a heating assembly for heating an aerosol-forming substrate, the heating assembly comprising a heater having an electrically resistive heating element and a heater base, and a heater mount coupled to the heater, the electrically resistive heating element including a first portion and a second portion configured to be heated to a higher temperature than the second portion when an electric current is passed through the heating element, wherein the first portion of the heating element is positioned in a heating region of the heater base and the second portion of the heating element is positioned in a retention region of the heater base, and the heater mount is secured to the retention region of the heater base, and the second portion of the electrically resistive heating element is longer than the first portion of the heating element, i.e., the second portion extends further along the length of the heater than the first portion.

[0008] The second portion of the resistive heating element may have a length of, for example, 12 mm to 20 mm. The length is determined relative to the longitudinal dimension of the heater. The second portion of the resistive heating element may have a length of about 13 mm or about 14 mm.

[0009] The first portion of the electrically resistive heating element may have a length of, for example, 8 mm to 12 mm. The first portion of the electrically resistive heating element may have a length of about 10 mm or about 11 mm.

[0010] In a preferred embodiment, the second portion of the electrically resistive heating element may extend along the length of the heater of 13.9 mm plus or minus 0.5 mm, and the first portion of the electrically resistive heating element may extend along the length of the heater of 10.5 mm plus or minus 0.5 mm.

[0011] The term "aerosol-forming substrate", as used herein, relates to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds can be released by heating the aerosol-forming substrate. The aerosol-forming substrate can conveniently be part of an aerosol-generating article or a smoking article.

[0012] The terms "aerosol-generating article" and "smoking article," as used herein, refer to an article comprising an aerosol-forming substrate capable of emitting a volatile compound capable of forming an aerosol. For example, an aerosol-generating article may be a smoking article that produces an aerosol that can be inhaled directly through a user's mouth into the user's lungs. The aerosol-generating article may be disposable. A smoking article with an aerosol-forming substrate containing tobacco is called a tobacco stick.

[0013] As a result of the current passing through the heating element, the first portion heats to a higher temperature than the second portion. In one embodiment, in use, the first portion of the heating element is configured to reach a temperature of about 300°C to about 550°C. Preferably, the heating element is configured to reach a temperature of about 320°C to about 350°C.

[0014] The heater mount provides structural support for the heater and ensures that the heater mount is securely fixed within the aerosol generating device. The heater mount can include a polymeric material and advantageously can be formed from a moldable polymeric material such as polyetheretherketone (PEEK). The use of a moldable polymer allows the heater mount to be molded around the heater, thereby firmly holding the heater. It also allows the heater mount to be manufactured in an inexpensive manner with the desired external shape and dimensions. The heater base may have mechanical features such as lugs or notches that enhance the fixation of the heater mount to the heater. Of course, other materials can be used for the heater mount, such as ceramic materials. Advantageously, the heater mount can be formed from a moldable ceramic material.

[0015] The heat mount preferably extends along a substantial portion of the retaining portion, which is the portion of the heater base on which the second portion of the heater element is supported. The heater base may be formed from a brittle material, and the heater mount may provide support to prevent bending and twisting of the heater.

[0016] The heater may need to penetrate a non-consumable element of the aerosol-generating article (such as a tube). It may be preferable for the heater mount to be shaped to increase the length of the heater in contact with the heater mount while also facilitating engagement with an aerosol-generating article having a non-consumable front element, such as a tube, located at the distal end of the article. Thus, at least a portion of the heater mount may be inwardly stepped or tapered as it extends along the retaining portion in a direction toward the heated portion. The step or taper may allow a portion of the heater mount to be inserted into the tubular front element. Thus, the heater mount may provide support along the majority of the retaining portion. Preferably, at least a portion of the heater mount extends along the retaining portion for more than 50% of the length of the retaining portion, and more preferably more than 60%, or more than 70%, or more than 80%, or more than 90%.

[0017] It may be preferable for at least a portion of the heater mount to be conical. Conical shapes include pyramidal shapes. The entire heater mount may be conical, with the apex of the cone pointing toward the heating portion of the heater. Alternatively, the heater mount may include a conical protrusion with a pointed tip toward the heating portion of the heater. A configuration in which at least a portion of the heater mount is conical may provide optimal heater support while allowing engagement with the aerosol-generating article.

[0018] Using a polymer to support the heater means that the heater temperature near the heater mount must be controlled below the temperature at which the polymer melts or degrades. The heater temperature at the portion passing through the non-consumable element at the distal end of the aerosol-generating article should also not exceed the temperature at which the material forming the non-consumable element degrades. Heating the non-consumable component of the aerosol-generating article is also inefficient. At the same time, the temperature of the portion of the heater within the aerosol-forming substrate must be sufficient to generate an aerosol with the desired characteristics. Therefore, it is desirable to extend the length of the second portion relative to the first portion. It is also desirable for the second portion of the heating element to be maintained below the maximum allowable temperature during use.

[0019] In an electrical resistance heater, the heat generated by the heater depends on the resistance of the heating element. For a given current, the higher the resistance of the heating element, the more heat will be generated. It is desirable to have most of the heat generated by a first portion of the heating element. Therefore, it is desirable for the first portion of the heating element to have a greater electrical resistance per unit length than the second portion of the heater element.

[0020] Advantageously, the heating element may have portions formed from different materials. A first portion of the heating element may be formed from a first material, and a second portion of the heating element may be formed from a second material, the first material having a higher coefficient of electrical resistance than the second material. For example, the first material may be Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire, and the second material may be gold, silver, or copper. The dimensions of the first and second portions of the heating element may also be different to provide a lower electrical resistance per unit length for the second portion.

[0021] Materials for the first and second portions of the heating element may be selected not only for their thermal properties but also for their electrical properties. Advantageously, the second portion of the heating element may have a low thermal conductivity to reduce heat conduction from the heating area to the heater mount. Therefore, the selection of a material for the second portion of the heating element may be a balance between high electrical conductivity and low thermal conductivity, at least in the region between the first portion of the heating element and the heater mount. In practice, gold has been found to be an excellent choice of material for the second portion of the heating element. Alternatively, silver may be included in the material for the second portion.

[0022] Advantageously, the second portion of the heating element may comprise two sections, each of which is separately connected to the first portion of the heating element to define an electrical flow path from one section of the second portion to the first portion and then to the other section of the second portion. A heater mount may surround both sections of the second portion. Of course, the second portion may comprise two or more portions, each electrically connected to the first portion.

[0023] The heating element may include a third portion configured for electrical connection to a power source, the third portion located on an opposite side of the heater mount from the first portion of the heating element. The third portion may be formed from a material different from the first and second portions and may be selected to provide low electrical resistance and good connection characteristics (e.g., easy solderability). In practice, silver has been found to be an excellent choice for the third portion. Alternatively, gold may be used as the material for the third portion. The third portion may include multiple sections, each connected to a section of the second portion of the heating element.

[0024] The heater base may be formed from an electrically insulating material, but may also be a ceramic material such as zirconium or alumina. The heater base may provide mechanically stable support for the heating element over a wide temperature range and may provide a rigid structure suitable for insertion into the aerosol-forming substrate. The heater base may have a flat surface on which the heating element is positioned and a tapered end configured for insertion into the aerosol-forming substrate. The heater base advantageously has a thermal conductivity of 2 watts per meter per degree Kelvin or less.

[0025] In one embodiment, the first portion of the heating element may be formed from a material having a defined relationship between temperature and resistivity, thereby allowing the heater to be used both to heat the aerosol-forming substrate and to monitor the temperature during use. Advantageously, the first portion has a higher temperature coefficient of resistance than the second portion. This ensures that the value of the resistance of the heater element primarily reflects the temperature of the first portion of the heater element. Platinum has been found to be a good choice for the first portion of the heater element.

[0026] Advantageously, the first portion of the heating element is spaced from the heater mount. The portion of the heater between the first portion of the heating element and the heater mount advantageously has a thermal gradient between a higher temperature at the first portion of the heater element and a lower temperature at the heater mount. The distance between the first portion of the heating element and the heater mount is selected to provide a sufficient temperature drop. However, it is also advantageous that the distance is no greater than necessary, both to reduce the size of the heater assembly and to make it as strong as possible. The longer the heater is in length relative to the heater mount, the more likely it is to break or bend if dropped or repeatedly inserted and removed from a solid aerosol-forming substrate.

[0027] Advantageously, under normal operating conditions, the first portion of the heating element at the point of contact with the heater mount is at a temperature of about 300 to about 550°C, while the second portion is at a temperature of less than 200°C. "Normal operating conditions" in this context means standard ambient temperature and pressure, which is a temperature of 298.15 K (25°C, 77°F) and an absolute pressure of 100 kPa (14.504 psi, 0.986 atm). Normal operating conditions include operation of the heater assembly when positioned within the housing of an aerosol generating device or when positioned outside the housing of an aerosol generating device.

[0028] Advantageously, the heater assembly is configured such that when the maximum temperature of the first portion is T1, the ambient temperature is T0 and the temperature of the second portion of the heater element in contact with the heater mount is T2, thus: (T1-T0) / (T2-T0)>2

[0029] The heating assembly may include one or more layers of material covering the heating element. Advantageously, a protective layer, formed of, for example, glass, is provided over the heating element to prevent oxidation or other corrosion of the heating element. The protective layer may completely cover the heater base. The protective layer, or other layer, may also improve heat distribution throughout the heater and may make the heater easier to clean. A layer of underlying material (such as glass) may also be provided between the heating element and the heater base to improve heat distribution over the heater. The underlying layer of material may also be used to improve the process of forming the heating element.

[0030] It should be clear that the dimensions of the heater may be selected to suit the application of the heating assembly, and that the width, length, and thickness of the heater may be selected independently. In one embodiment, the heater is substantially blade-shaped and has a tapered end for insertion into the aerosol-forming substrate. The heater may have a total length of about 15 mm to about 30 mm, and advantageously about 20 mm to about 25 mm. The surface of the heater on which the heating element is located may have a width of about 2 mm to about 10 mm, and advantageously about 3 mm to about 6 mm. The heater has a thickness of about 0.2 mm to about 0.5 mm, and preferably 0.3 mm to 0.4 mm. The active heating area of ​​the heater, corresponding to the portion of the heater within which the first portion of the heating element is located, may have a length of 5 mm to 20 mm, and advantageously 8 mm to 15 mm. The distance between the heater mount and the first portion of the heating element may be at least 2 mm, and advantageously at least 2.5 mm. In a preferred embodiment, the distance between the heater mount and the first portion of the heating element is 3 mm.

[0031] In one aspect of the present invention, there may be provided an aerosol generating device comprising a housing, a heating assembly according to the above description, wherein the heater mount is coupled to the housing, a power supply coupled to the heating element, and a control element configured to control power supply from the power supply to the heating element. The housing may define a cavity surrounding a first portion of the heating element, the cavity being configured to receive an aerosol-forming article including an aerosol-forming substrate.

[0032] As used herein, "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, such as part of a smoking article. The aerosol-generating device may be a smoking device that interacts with the aerosol-forming substrate of the aerosol-generating article to generate an aerosol that can be inhaled directly through the user's mouth into the user's lungs. The aerosol-generating device may also be a holder.

[0033] The heater mount may form a surface that closes one end of the recess.

[0034] The device is preferably a portable or handheld device that is comfortable to hold between the fingers of one hand. The device may be substantially cylindrical in shape and have a length of 70-120 mm. The maximum diameter of the device is preferably 10-20 mm. In one embodiment, the device has a polygonal cross-section and a protruding button formed on one side. In this embodiment, the diameter of the device is 12.7-13.65 mm from one flat surface to the opposite flat surface, 13.4-14.2 mm from one edge to the opposite edge (i.e., from the intersection of two surfaces on one side of the device to the corresponding intersection on the other side), and 14.2-15 mm from the top of the button to the opposite bottom flat surface.

[0035] The device may be an electrically heated smoking device.

[0036] The device may include other heaters in addition to the heater assembly according to the first embodiment. For example, the device may include an external heater located near the periphery of the cavity. The external heater may take any suitable form. For example, the external heater may take the form of one or more flexible heating foils on a dielectric substrate such as polyimide. The flexible heating foil may be shaped to fit the periphery of the cavity. Alternatively, the external heater may take the form of a metal grid(s), a flexible printed circuit board, a molded interconnect device (MID), a ceramic heater, a flexible carbon fiber heater, or may be formed using a coating technique such as plasma deposition on a suitably shaped substrate. The external heater may also be formed using a metal that has a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating material. The external heater thus formed may be used both to heat the external heater and to monitor its temperature during operation.

[0037] The power supply may be any suitable power source, for example, a DC voltage source such as a battery. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power supply may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery, such as a lithium-cobalt, lithium-iron-phosphate, lithium-titanium-oxide, or lithium-polymer battery.

[0038] The control element may be a simple switch, or it may be an electrical circuit and may include one or more microprocessors or microcontrollers.

[0039] In a third aspect of the present invention, there is provided an aerosol generation system comprising an aerosol generation device according to the second aspect of the present invention and one or more aerosol-forming articles configured to be received in a cavity of the aerosol-generating device, the aerosol-generating article comprising a non-consumable element located at a distal end of the article upstream of the aerosol-forming substrate.

[0040] The aerosol-generating system may comprise a heated aerosol-generating article, the heated aerosol-generating article comprising multiple components including an aerosol-forming substrate assembled within a wrapper to form a rod having an oral end and a distal end upstream of the oral end. A hollow tube, which may have an outer diameter of 5 mm to 15 mm and a length of 5 mm to 15 mm, may be positioned upstream from the aerosol-forming substrate within the wrapper. A heater of the aerosol-generating device extends through the lumen of the hollow tube and is of sufficient length to penetrate the aerosol-forming substrate when the heated aerosol-generating article is engaged with the aerosol-generating device.

[0041] The hollow tube may be rigid and may be formed from a substantially non-flammable material. As defined herein, a non-flammable material is one that is difficult or impossible to ignite using a flame in the temperature range of 800° C. to 1700° C., and generally 800° C. to 1200° C. In general, any material that does not substantially emit toxic or other harmful or undesirable compounds in the temperature range of approximately 800° C. to 1200° C., or up to 1700° C., is within the scope of a substantially non-flammable material as contemplated herein.

[0042] The pierceable membrane may span one end of the hollow tube. The hollow tube has a proximal end and a distal end. The pierceable membrane may span the distal end of the hollow tube. The pierceable membrane may span the proximal end of the hollow tube. The hollow tube with the pierceable membrane may protect the distal end of the rod from ignition if a user applies a flame and inhales on the mouth end of the article. Heat from the flame impinges on the hollow tube, which is non-flammable. An aerosol-forming substrate positioned downstream of the hollow tube is less likely to reach its combustion temperature than if it were positioned at the distal end of the heated aerosol-generating article. Furthermore, the pierceable membrane helps prevent air from being drawn through the rod. Thus, the risk of inadvertent or unintentional ignition of the aerosol-forming substrate is reduced.

[0043] The hollow tube is preferably a rigid hollow tube formed from a polymer, metal, or ceramic. Preferably, the rigid hollow tube is formed from a material selected from the list consisting of metal foil, ceramic, highly filled paper, cellulose acetate, and polyaryletherketone (PAEK) polymer.

[0044] The aerosol-forming article may be a smoking article. In operation, the smoking article comprising the aerosol-forming substrate may be partially contained within the aerosol-generating device.

[0045] The smoking article may be substantially cylindrical in shape. The smoking article may be substantially elongated. The smoking article may also have a length and a circumference substantially perpendicular to the length. The aerosol-forming substrate may be substantially cylindrical in shape. The aerosol-forming substrate may be substantially elongated. The aerosol-forming substrate may also have a length and a circumference substantially perpendicular to the length.

[0046] The smoking article may have a total length of about 30 mm to about 100 mm. The smoking article may have an outer diameter of about 5 mm to about 12 mm. The smoking article may include a filter plug. The filter plug may be located at the downstream end of the smoking article. The filter plug may be a cellulose acetate filter plug. The filter plug may be about 7 mm long in one embodiment, but may have a length of about 5 mm to about 10 mm.

[0047] In one embodiment, the smoking article has a total length of approximately 45 mm. The smoking article may have an outer diameter of approximately 7.2 mm. Furthermore, the length of the aerosol-forming substrate may be approximately 10 mm. Alternatively, the length of the aerosol-forming substrate may be approximately 12 mm. Furthermore, the diameter of the aerosol-forming substrate may be between approximately 5 mm and approximately 12 mm. The smoking article may include an outer paper wrapper. Furthermore, the smoking article may include a separation between the aerosol-forming substrate and the filter plug. The separation may be approximately 18 mm, but may range from approximately 5 mm to approximately 25 mm.

[0048] The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may include both solid and liquid components. The aerosol-forming substrate may include a tobacco-containing material that includes volatile tobacco flavor compounds that are released from the substrate upon heating. Alternatively, the aerosol-forming substrate may include a non-tobacco material. The aerosol-forming substrate may further include an aerosol former that promotes the formation of a dense, stable aerosol. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0049] When the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of powder, granules, pellets, shreds, spaghetti, strips, or sheets, including one or more of herb leaves, tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, cast leaf tobacco, and expanded tobacco. The solid aerosol-forming substrate may be in loose form, or may be provided with a suitable container or cartridge. Optionally, the solid aerosol-forming substrate may contain additional tobacco or non-tobacco volatile flavor compounds that are released upon heating of the substrate. The solid aerosol-forming substrate may also include, for example, capsules containing additional tobacco or non-tobacco volatile flavor compounds, which dissolve during heating of the solid aerosol-forming substrate.

[0050] As used herein, "homogenized tobacco" refers to a material formed by agglomerating particulate tobacco. The homogenized tobacco may be in the form of a sheet. The homogenized tobacco material may have an aerosol former content of greater than 5% by dry weight. Alternatively, the homogenized tobacco material may have an aerosol former content of about 5 to about 30 weight percent by dry weight. The homogenized tobacco material sheet may be formed by agglomerating particulate tobacco obtained by grinding or otherwise combining one or both of tobacco lamina and tobacco stem. Alternatively, or additionally, the homogenized tobacco material sheet may include one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed, for example, during tobacco processing, handling, and transportation. The homogenized tobacco material sheet may include one or more inherent binders (i.e., tobacco intrinsic binders), one or more extrinsic binders (i.e., tobacco extrinsic binders), or a combination thereof to aid in the cohesion of the particulate tobacco, although alternatively or additionally, the homogenized tobacco material sheet may include other additives, including but not limited to tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof.

[0051] Optionally, the solid aerosol-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may be in the form of a powder, granules, pellets, pieces, spaghetti, strips, or sheets. Alternatively, the carrier may be a tubular carrier having a thin layer of solid substrate disposed on its interior surface, its exterior surface, or both its interior and exterior surfaces. Such a tubular carrier may be formed, for example, from paper or paper-like material, nonwoven carbon fiber mat, a thin, open-mesh metal screen, or a perforated metal foil or any other thermally stable polymeric matrix.

[0052] In a particularly preferred embodiment, the aerosol-forming substrate comprises an assembly of crimped sheets of homogenized tobacco material. As used herein, the term "crimped sheet" refers to a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled. This conveniently facilitates assembly of the crimped sheets of homogenized tobacco material to form the aerosol-forming substrate. However, it is recognized that a crimped sheet of homogenized tobacco material for inclusion in an aerosol-generating article may alternatively or additionally have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled. In certain embodiments, the aerosol-forming substrate may comprise an assembly of sheets of homogenized tobacco material that are substantially uniformly textured over substantially its entire surface. For example, the aerosol-forming substrate may comprise an assemblage of a crimped sheet of homogenized tobacco material containing a plurality of substantially parallel ridges or corrugations that are substantially uniformly spaced across the width of the sheet.

[0053] The solid aerosol-forming substrate may be disposed on the surface of the carrier in the form of, for example, a sheet, foam, gel or slurry. The solid aerosol-forming substrate may be deposited on the entire surface of the carrier, or alternatively, may be deposited in a pattern to provide a non-uniform flavor delivery during use.

[0054] An aerosol generating system is a combination of an aerosol generating device and one or more aerosol generating articles for use with the device, although an aerosol generating system may include additional components, such as a charging unit for recharging an on-board power supply in an electrically operated or electric aerosol generating device.

[0055] Although the disclosure has been described with reference to different aspects, it will be apparent that features described in connection with one aspect of the disclosure may be applied to other aspects of the disclosure. In particular, aspects of a heater, assembly, device, or method according to one aspect of the invention may also be applied to any other aspect of the invention. Moreover, although the present disclosure is by reference to smoking devices, it will be apparent that medical inhaler-type devices may use the features, apparatus, and functionality described herein. Embodiments of the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0056] [Figure 1] FIG. 1 is a schematic diagram of an aerosol generating device. [Figure 2] FIG. 2 is a schematic cross-sectional view of an embodiment of a heated aerosol-generating article for use with an aerosol-generating device. [Figure 3] FIG. 3 is a schematic cross-sectional view of a further embodiment of a heated aerosol-generating article for use with an aerosol-generating device. [Figure 4] FIG. 4 is a schematic cross-sectional view of the front end of an aerosol generating device of the type shown in FIG. 1, with a heater inserted into the aerosol-generating article. [Figure 5]FIG. 5 is a schematic diagram of a heater according to the present invention. [Figure 6] FIG. 6 shows the heater of FIG. 5 with a heater mount installed. [Figure 7] FIG. 7 illustrates an embodiment of a heater assembly including a conical heater mount. DETAILED DESCRIPTION OF THE INVENTION

[0057] 1 illustrates in a simplified manner the components of an embodiment of an electrically heated aerosol generating system 100. In particular, the elements of the electrically heated aerosol generating system 100 are not drawn to scale in FIG. 1. Elements that are not relevant to an understanding of this embodiment have been omitted from the simplified FIG.

[0058] The electrically heated aerosol generating system 100 comprises an aerosol generating device having a housing 10 and an aerosol-forming article 12 (e.g., a tobacco stick). The aerosol-forming article 12 comprises an aerosol-forming substrate that is pressed within the housing 10 into thermal proximity with a heater 14. The aerosol-forming substrate releases various volatile compounds at different temperatures. By controlling the maximum operating temperature of the electrically heated aerosol generating system 100, the release of undesirable volatile compounds can be controlled.

[0059] Within housing 10 is an electrical energy source 16, such as a rechargeable lithium-ion battery. A controller 18 is connected to heater 14, electrical energy source 16, and a user interface 20 (e.g., buttons or a display). Controller 18 controls the power supplied to heater 14 to regulate its temperature. Typically, the aerosol-forming substrate is heated to a temperature of 250-450°C.

[0060] 2 illustrates a heated aerosol-generating article 101 according to a preferred embodiment. The aerosol-generating article 101 includes four coaxially aligned elements: a rigid hollow tube 30, an aerosol-forming substrate 21, an aerosol-cooling element 40, and a mouthpiece 50. These four elements are arranged consecutively and surrounded by an outer wrapper 60 to form the heated aerosol-generating article 101. The aerosol-generating article 101 has a proximal or oral end 70 that a user inserts into their mouth during use, and a distal end 80 at the opposite end of the aerosol-generating article 101 from the oral end 70.

[0061] Additionally, the distal end 80 of the aerosol-generating article may be described as the upstream end of the aerosol-generating article 101, and the oral end 70 of the aerosol-generating article 101 may also be described as the downstream end of the aerosol-generating article 101. Elements of the aerosol-generating article 101 located between the oral end 70 and the distal end 80 may be described as being upstream of the oral end 70, or alternatively, downstream of the distal end 80.

[0062] A rigid hollow tube 30 is located at the extreme distal or upstream end of the aerosol-generating article 101. In the article shown in Figure 2, the rigid hollow tube 30 is a hollow ceramic tube. This rigid hollow tube 30 may protect the aerosol-forming substrate from a flame applied to the distal end of the article 101, thereby providing a means to reduce the risk of inadvertent ignition.

[0063] In the article illustrated in Figure 2, the aerosol-forming substrate 21 comprises an assembly of sheets of crimped homogenized tobacco material surrounded by a wrapper. The crimped sheets of homogenized tobacco material contain glycerin as an aerosol-forming agent.

[0064] The aerosol cooling element 40 is located directly downstream of and adjacent to the support element 30. In use, volatile material emitted from the aerosol-forming substrate 21 passes along the aerosol cooling element 40 toward the mouth end 70 of the aerosol-generating article 101. The volatile material may cool within the aerosol cooling element 40 to form an aerosol that is inhaled by the user. In the article illustrated in FIG. 2, the aerosol cooling element comprises an assembly of crimped sheets of polylactic acid surrounded by a wrapper 90. The assembly of crimped sheets of polylactic acid defines a plurality of longitudinal channels extending along the length of the aerosol cooling element 40.

[0065] Mouthpiece 50 is located directly downstream of and adjacent to aerosol cooling element 40. In the article illustrated in Figure 2, mouthpiece 50 comprises a conventional cellulose acetate tow filter with low filtration efficiency.

[0066] To assemble the aerosol-generating article 101, the above four elements are aligned and tightly wrapped within the outer wrapper 60. In some embodiments, the distal end portion of the outer wrapper 60 of the aerosol-generating article 101 may be surrounded by a strip of tipping paper.

[0067] The aerosol-generating article 101 shown in Figure 2 is designed to engage an aerosol-generating device that includes a heating element for smoking or consumption by a user. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate 21 of the aerosol-generating article 101 to a temperature sufficient to form an aerosol, which is drawn downstream through the aerosol-generating article 101 and inhaled by the user.

[0068] 3 illustrates a further embodiment of a suitable aerosol-generating article 201. Article 201 includes five elements: a rigid hollow tube 202, an aerosol-forming substrate 207, a hollow cellulose acetate tube 206, a transfer section 204, and a mouthpiece filter 203. These five elements are arranged in a sequential coaxial array and assembled by cigarette paper 205 to form a rod. When assembled, article 201 is 52 millimeters long and 7.2 millimeters in diameter.

[0069] The rigid hollow tube 202 is a ceramic tube 7 millimeters in length.

[0070] The aerosol-forming substrate 207 is positioned downstream of the rigid hollow tube 202 and comprises a bundle of crimped cast leaf tobacco wrapped in filter paper. The cast leaf tobacco contains additives including glycerin as an aerosol-forming additive.

[0071] Cellulose acetate tube 206 is positioned immediately downstream of aerosol-forming substrate 207 and is formed from cellulose acetate. Tube 206 defines an opening with a diameter of 3.3 millimeters. One function of tube 206 is to position aerosol-forming substrate 207 toward distal end 230 of article 201 so that it can come into contact with the heating element. Tube 206 serves to prevent aerosol-forming substrate 207 from being pushed along article 201 toward mouth end 220 when the heating element is inserted.

[0072] Transfer section 204 comprises an 18 millimeter long thin-walled tube. Transfer section 204 allows the volatile material to be released from aerosol-forming substrate 207 and pass along article 201 toward mouth end 20. The volatile material may cool in transfer section 204 to form an aerosol. An aerosol cooling element, such as a collection of sheets of crimped polylactic acid, may be used instead of a transfer section.

[0073] Mouthpiece filter 203 is a conventional mouthpiece filter formed from cellulose acetate tow and having a length of 7 millimeters.

[0074] The five elements identified above are assembled by intimately wrapping them into cigarette paper 205 .

[0075] Figure 4 illustrates portions of an aerosol-generating system 1000 including an aerosol-generating device 110 and an aerosol-generating article 101 according to the embodiment of the article described above and illustrated in Figure 2. The system may alternatively include an aerosol-generating article as described in connection with Figure 3 above, or any other suitable aerosol-generating article.

[0076] The aerosol-generating device 110 includes a heating element 120. As shown in FIG. 4, the heating element 120 is mounted within the aerosol-generating-article-receiving chamber of the aerosol-generating device 110. In use, a user inserts the aerosol-generating article 101 into the aerosol-generating-article-receiving chamber of the aerosol-generating device 110 so that the heating element 120 penetrates and is inserted directly into the aerosol-forming substrate 21 of the aerosol-generating article 101 through the lumen of the rigid hollow tube 30, as shown in FIG. 4. In the embodiment shown in FIG. 4, the heating element 120 of the aerosol-generating device 110 is a heater blade. The heating element 120 has a heating portion 1201 and a holding portion 1202. The holding portion 1202 extends along a length of the heating element 120 that is longer than the heating portion 1201. In use, the heating portion 1201 is inserted into the aerosol-forming substrate 21 of the aerosol-generating article 101. A PEEK heater mount 1300 is mounted on the retaining portion 1202 of the heating element 120. A conical projection 1310 extends from the surface of the heater mount and extends along the retaining portion of the heating element 120 to increase the proportion of the heating element 120 that is supported by the heater mount.

[0077] The aerosol-generating device 110 includes a power source and electronics capable of activating the heating element 120. Such activation may be manual or may occur automatically in response to a user withdrawing an aerosol-generating article 101 that is inserted into the aerosol-generating-article-receiving chamber of the aerosol-generating device 110. A plurality of openings are provided in the aerosol-generating device to allow air to flow through the aerosol-generating article 101; the direction of air flow is illustrated by the arrows in FIG. 4.

[0078] When the internal heating element 120 is inserted into the aerosol-forming substrate 21 of the aerosol-generating article 101 and activated, the aerosol-forming substrate 21 is heated to a temperature of approximately 375 degrees Celsius by the heating element 120 of the aerosol-generating device 110. At this temperature, volatile compounds are emitted from the aerosol-forming substrate 21 of the aerosol-generating article 101. As a user draws on the mouth end 70 of the aerosol-generating article 101, the volatile compounds emitted from the aerosol-forming substrate 21 are drawn downstream through the aerosol-generating article 101 and condense to form an aerosol that is drawn through the mouthpiece 50 of the aerosol-generating article 101 into the user's mouth.

[0079] As the aerosol passes downstream through the aerosol cooling element 40, the temperature of the aerosol decreases due to the transfer of thermal energy from the aerosol to the aerosol cooling element 40. When the aerosol enters the aerosol cooling element 40, its temperature is approximately 60 degrees Celsius. Due to cooling within the aerosol cooling element 40, when the aerosol exits the aerosol cooling element, its temperature is approximately 40 degrees Celsius.

[0080] FIG. 5 illustrates a heater element 14 of the type shown in FIG. 4 in more detail. The heater 14 includes an electrically insulating heater base 81 that defines the shape of the heating element 14. The heater base 81 is formed from an electrically insulating material, which may be, for example, alumina (Al2O3) or zirconium (ZrO2). The electrically insulating material may be any suitable electrically insulating material, and it will be apparent to those skilled in the art that many ceramic materials are suitable for use as the electrically insulating base. The heater base 81 is substantially blade-shaped. That is, the heater base has a length extending along the longitudinal axis of the aerosol-forming article that engages the heater during use, a width, and a thickness. The width is greater than the thickness. The heater base 81 terminates in a tip or spike 90 for penetrating the aerosol-forming substrate 30.

[0081] A heating element 82, formed from a conductive material, is deposited on the flat surface of the heater substrate 80 using evaporation or any other suitable technique. The heating element is formed of three distinct sections. The first section 84 is formed from platinum. The first section is located within the active heating area, or heating portion 91. This is the area of ​​the heater that reaches its maximum temperature during use and provides heat to the aerosol-forming substrate. The first section is U-shaped or hairpin-shaped. The second section 86 is formed from gold. The second section includes two parallel tracks, each connecting to an end of the first section 84. The second section is located within the retaining portion, spanning the entire retaining area 93 of the heater. The retaining area is the area of ​​the heater that contacts the heater mount 26, as shown in FIG. 6. The third section 88 is formed from silver. The third section is located in the connection portion 95 and provides a bonding pad to which external wires can be secured using solder paste or other adhesive techniques. The third portion includes two parallel pads, each connected to the end of one of the parallel tracks of the second portion 86 opposite the first portion 84. The third portion 88 is positioned opposite the retention area 93 of the first portion.

[0082] The shape, thickness, and width of the first, second, and third sections can be selected to provide the desired resistance and temperature distribution during use. However, the first section has significantly greater electrical resistance per unit length than the second and third sections, resulting in the first section generating the most heat and becoming the hottest when current passes through the heating element 82. The second and third sections are configured to have very low electrical resistance, resulting in negligible Joule heating. The total electrical resistance of the heating element is approximately 0.80 ohms at 0°C, rising to approximately 2 ohms as the active heating area 91 reaches 400°C. The battery voltage of a lithium-ion battery is approximately 3.7 volts, resulting in a typical peak current provided by a power supply (at 0°C) of approximately 4.6 A.

[0083] The length of the first portion 84 is 10.5 mm. The length of the second portion 86 is 13.9 mm.

[0084] Platinum has a positive temperature coefficient of resistance, so the electrical resistance of the first portion 84 increases with increasing temperature. Gold and silver have lower temperature coefficients of resistance, so the second and third portions do not increase in temperature as much as the first portion. This means that the change in resistance of the second and third portions is small compared to the change in resistance of the first portion. As a result, the resistance of the heating element 82 can be used to measure the temperature of the first portion 84 of the heating element, which is the temperature of the heater portion in contact with the aerosol-forming substrate. An arrangement for using a resistive element as both a heater and a temperature sensor is described in EP 2110033 B1.

[0085] FIG. 6 shows the heater 14 incorporated into a heater mount 26 to form a heating assembly. The heater mount 26 is formed from polyetheretherketone (PEEK) and is injection molded around the heater at the retention area 93. The heater base 81 may be formed with a notch or protrusion in the retention area to ensure a strong fit between the heater mount and the heater. In this embodiment, the heater mount 26 has a circular cross-section to mate with the circular housing of the aerosol generation device. However, the heater mount can be molded with any desired shape and any desired mating characteristics for mating with other components of the aerosol generation device.

[0086] FIG. 7 illustrates an optional shape for heater mount 2000. Heater mount 2000 is molded around the heater 2200 with a retaining portion for the heater. The heater mount includes a portion that is circular in cross section and has parallel sides for engaging the housing of the aerosol generating device. The heater mount also includes a tapered portion that forms a cone with a pointed end toward the tip of the heater. The conical shape of this portion of the heater mount allows additional support for the heater. In a preferred embodiment, the heater support contacts at least 9 or 10 mm of the heater's length.

[0087] The above-described exemplary embodiments are illustrative and not limiting. In light of the exemplary embodiments discussed above, other embodiments consistent with the above exemplary embodiments will now be apparent to those skilled in the art.

Claims

1. 1. A heating assembly for heating an aerosol-forming substrate, comprising: a heater having an electrically resistive heating element and a heater substrate; a heater mount coupled to the heater; the electrically resistive heating element comprises a first portion and a second portion configured such that when an electric current is passed through the heating element, the first portion is heated to a higher temperature than the second portion, the first portion of the heating element is positioned on a heating region of the heater base and the second portion of the heating element is positioned on a holding region of the heater base, the heater mount is secured to the holding region of the heater base, and the second portion of the electrically resistive heating element is longer than the first portion of the electrically resistive heating element; At least a portion of the heater mount tapers inwardly as it extends along the support area in a direction toward the heating area. Heating assembly.

2. The heating assembly of claim 1 , wherein the second portion of the electrically resistive heating element has a length of between 12 mm and 20 mm, for example about 13 mm or about 14 mm.

3. A heating assembly according to claim 1 or 2, wherein the first portion of the electrically resistive heating element has a length of between 8 mm and 12 mm, for example about 10 mm or about 11 mm.

4. 4. The heating assembly of claim 1, wherein the second portion of the electrically resistive heating element extends along a length of the heater of 13.9 mm plus or minus 0.5 mm, and the first portion of the electrically resistive heating element extends along a length of the heater of 10.5 mm plus or minus 0.5 mm.

5. The heating assembly of any one of claims 1 to 4, wherein the heater mount comprises a moldable polymeric material, such as polyetheretherketone (PEEK).

6. 6. The heating assembly of claim 1, wherein the first portion of the heating element is formed from a first material and the second portion of the heating element is formed from a second material, the first material having a higher coefficient of electrical resistivity than the second material.

7. 7. The heating assembly of claim 1, wherein the second portion of the electrically resistive heating element comprises first and second sections, each of the first and second sections being separately connected to the first portion of the heating element to define an electrical flow path from the first section of the second portion to the first portion and then from the first section to the second section of the second portion.

8. 8. The heating assembly of claim 1, wherein the heating element includes a third portion configured for electrical connection to a power source, the third portion being positioned on an opposite side of the heater mount from the first portion of the heating element.

9. The heating assembly of claim 8 , wherein the third portion is formed from a different material than the first portion and the second portion.

10. The heating assembly of any preceding claim, wherein the first portion of the heating element is spaced from the heater mount.

11. The heating assembly of any preceding claim, wherein the first portion has a greater temperature coefficient of resistance than the second portion.

12. The heating assembly of any one of claims 1 to 11, wherein at least a portion of the heater mount is conical.

13. The heating assembly of any one of claims 1 to 12, wherein the heater mount is generally conical in shape, with the apex of the cone pointing towards the heating area of ​​the heater.

14. The heating assembly of any preceding claim, wherein the heater mount comprises a conical protrusion with a pointed tip toward the heating region of the heater.

15. The heating assembly of any preceding claim, wherein at least a portion of the heater mount extends along the retention area for more than 50% of the length of the retention area.

16. The maximum temperature of the first portion is T 1 When the ambient temperature is T 0 and the temperature of the second portion of the heater in contact with the heater mount is T 2 and the following formula: (T 1 -T 0 ) / (T 2 -T 0 )>2 The heating assembly according to any one of claims 1 to 15, wherein

17. An aerosol generating device comprising: a housing; a heating assembly according to any one of claims 1 to 16, wherein the heater mount is coupled to the housing; a power supply coupled to the heating element; and a control element configured to control the supply of power from the power supply to the heating element.

18. 18. The aerosol generating device according to claim 17, wherein the housing defines a cavity surrounding the first portion of the heating element, the cavity being configured to receive an aerosol-forming article comprising an aerosol-forming substrate.

19. 19. An aerosol generating device according to claim 17 or 18, wherein the device is a handheld device.

Images