Heater assembly with separated sealing element

Abstract

A heater assembly (410) for an aerosol-generating device, the heater assembly comprising: a first heater housing (412) comprising an air inlet (418); a second heater housing (414) comprising an aerosol outlet (420); a tubular heater (416) for heating the aerosol-forming substrate; an airflow path (422) extending from the air inlet through the heater assembly to the aerosol outlet, the airflow path passing through the first heater housing, the tubular heater, and the second heater housing; a first sealing element (426) configured to seal the first heater housing to the tubular heater; and a second sealing element (424) configured to seal the second heater housing to the tubular heater; wherein the first and second sealing elements are separated from the airflow path.

Description

Technical Field

[0001] The present disclosure relates to a heater assembly for an aerosol generating device. The present disclosure further relates to an aerosol generating device comprising a heater assembly. In particular, but not exclusively, the present disclosure relates to a handheld electrically operated aerosol generating device for heating an aerosol-forming substrate to generate an aerosol and for delivering the aerosol to a user's mouth. The present disclosure also relates to an aerosol generating system comprising an aerosol generating device and an aerosol-forming substrate. Background Art

[0002] Aerosol generating devices that heat an aerosol-forming substrate to generate an aerosol without burning the aerosol-forming substrate are known in the art. The aerosol-forming substrate is typically disposed within an aerosol-generating article together with other components such as a filter. The aerosol-generating article may have a strip shape to insert the aerosol-generating article into a heating chamber of the aerosol-generating device. The heating element is typically arranged in or around the heating chamber to heat the aerosol-forming substrate after the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device.

[0003] The heating chamber can be arranged in the housing of the aerosol generating device and form a part of the airflow path through the aerosol generating device. One method of attaching the heating chamber to the housing of the aerosol generating device is by mechanical press fit. However, due to manufacturing tolerances, it is difficult to achieve an airtight seal between the housing and the heating chamber by mechanical press fit, and a gap may be maintained between the housing and the heating chamber, and the aerosol may escape from the heating chamber and the airflow path into the portion of the housing surrounding the heating chamber through the gap. The escaping aerosol may condense in the portion of the housing surrounding the heating chamber and form a slurry. When the consumer uses the aerosol generating device, the slurry may be repeatedly heated, which may produce undesirable by-products. These by-products may enter the airflow path via the gap between the housing and the heating chamber, and adversely affect the consumer's experience of using the aerosol generating device.

[0004] Furthermore, the gap between the housing and the heating chamber may result in heat loss from the heating chamber, which may reduce the thermal efficiency of the device and the heat available to heat the aerosol-forming substrate. This may also reduce the consumer experience. Summary of the invention

[0005] It is desirable to provide a heater assembly for an aerosol generating device having an improved seal to its airflow path. It is desirable to provide a heater assembly for an aerosol generating device that is more energy efficient and improves the delivery of the aerosol to a user.

[0006] According to an example of the present disclosure, a heater assembly for an aerosol generating device is provided. The heater assembly may include a first heater housing. The first heater housing may include an air inlet. The heater assembly may include a second heater housing. The second heater housing may include an aerosol outlet. The heater assembly may include a tubular heater for heating an aerosol-forming substrate to generate an aerosol. The heater assembly may include an airflow path. The airflow path may extend from the air inlet through the heater assembly to the aerosol outlet. The airflow path may pass through the first heater housing. The airflow path may pass through the tubular heater. The airflow path may pass through the second heater housing. The heater assembly may include a first sealing element. The first sealing element may be configured to seal the first heater housing to the tubular heater. The heater assembly may include a second sealing element. The second sealing element may be configured to seal the second heater housing to the tubular heater. The first sealing element may be separated from the airflow path. The second sealing element may be separated from the airflow path.

[0007] According to an example of the present disclosure, a heater assembly for an aerosol generating device is provided. The heater assembly includes: a first heater housing including an air inlet; a second heater housing including an aerosol outlet; a tubular heater for heating an aerosol-forming substrate to generate an aerosol; and an airflow path extending from the air inlet through the heater assembly to the aerosol outlet, the airflow path passing through the first heater housing, the tubular heater, and the second heater housing. The heater assembly also includes a first sealing element and a second sealing element, the first sealing element being configured to seal the first heater housing to the tubular heater, and the second sealing element being configured to seal the second heater housing to the tubular heater. The first and second sealing elements are separated from the airflow path.

[0008] Advantageously, the first and second sealing elements provide a seal around the tubular heater. This helps to suppress aerosols from leaking from the tubular heater into the first and second heater housings, which reduces the possibility of forming slurries in the first and second heater housings and the possibility of generating undesirable byproducts. In addition, the first and second sealing elements are separated from the airflow path, which suppresses the contact between the heated aerosol and the air and the sealing element. This helps to reduce the possibility that the sealing element is degraded by the aerosol and potentially releases undesirable byproducts. In addition, the sealing element limits the aerosol or airflow that undesirable byproducts enter the airflow path. In addition, the first and second sealing elements are separated from the airflow path to suppress the contact between the aerosol and the first and second sealing elements. This helps to prevent the aerosol from degrading the sealing element, and reduces the possibility of any material released from the sealing element entering the airflow path. Another advantage of providing the first and second sealing elements that seal around the tubular heater is that it helps to reduce the leakage of heated aerosol and air from the tubular heater, which improves the energy efficiency of the heater assembly.

[0009] As used herein, when defining the position of the first and second sealing elements relative to the airflow path, the term "separated" means that there is a physical barrier between the sealing elements and the airflow path. For example, the tubular heater can act as a physical barrier between the first and second sealing elements and the airflow path, that is, the wall of the tubular heater can be arranged between the first and second sealing elements and the airflow path. In addition, the first and second heater housings or the interface between the first and second heater housings and the tubular heater can act as a physical barrier between the first and second sealing elements and the airflow path.

[0010] The first sealing element may comprise an annular seal. The first sealing element may be arranged between the inner surface of the first heater housing and the outer surface of the tubular heater. Advantageously, in this arrangement, the first sealing element is placed on the side of the tubular heater opposite to where the airflow path passes, so that the tubular heater acts as a physical barrier between the first sealing element and the airflow path.

[0011] The second sealing element may include an annular seal. The second sealing element may be arranged between the inner surface of the second heater housing and the outer surface of the tubular heater. Advantageously, in this arrangement, the second sealing element is placed on the side of the tubular heater opposite to where the airflow path passes, so that the tubular heater acts as a physical barrier between the second sealing element and the airflow path.

[0012] At least one of the first and second sealing elements may be arranged in a groove or recess formed in the inner surface of a corresponding one of the first and second heater housings. The first sealing element may be arranged in a groove or recess formed in the inner surface of the first heater housing. The second sealing element may be arranged in a groove or recess formed in the inner surface of the second heater housing. The first end of the tubular heater may be arranged in a groove or recess formed in the inner surface of the first heater housing. The second end of the tubular heater may be arranged in a groove or recess formed in the inner surface of the second heater housing. Advantageously, the groove provides an effective way to hold the sealing element in place and also helps to protect the sealing element. Advantageously, the groove provides an effective way to hold the tubular heater in place.

[0013] The first heater housing may include a tube holder for holding the tubular heater. The airflow path may pass through the tube holder. The tube holder provides an effective way to hold or support the tubular heater. The tube holder also helps to space the tubular heater from the rest of the first heater housing to thermally insulate or isolate the rest of the first heater housing from the relatively high temperatures reached by the tubular heater.

[0014] The first sealing element may be arranged between the tube holder and the outer surface of the tubular heater.This arrangement helps seal the tube holder component of the first heater housing to the tubular heater.

[0015] The first and second sealing elements may comprise opposite end sections of the tubular heater. The opposite end sections may be sealingly secured to the inner surfaces of the first and second heater housings. Advantageously, in this arrangement, the interface between the first and second heater housings and the tubular heater acts as a physical barrier between the first and second sealing elements and the airflow path. That is, the sealing engagement of the opposite end sections of the tubular heater with the inner surfaces of the first and second heater housings helps seal the airflow path and protect the opposite end sections.

[0016] The opposed end sections of the tubular heater may be fixed in sealing engagement in grooves or recesses formed in the inner surfaces of the first and second heater housings. Advantageously, in this arrangement, the portions of the first and second heater housings surrounding the grooves or recesses act as a physical barrier between the opposed end sections of the tubular heater and the airflow path so that aerosol cannot contact the sealing element.

[0017] The opposing end sections of the tubular heater may be embedded in the inner surfaces of the first and second heater housings. Advantageously, in this arrangement, the portions of the first and second heater housings surrounding the embedded opposing end sections of the tubular heater act as a physical barrier between the opposing end sections of the tubular heater and the airflow path so that aerosol cannot contact the sealing element.

[0018] The first and second heater shells may be sealed or connected to the opposing end sections of the tubular heater by one or more of the following processes: insert molding, overmolding, heat staking, high frequency welding, and ultrasonic welding.

[0019] The opposing end sections of the tubular heater have a surface finish having an ISO roughness value in the range of N9 to N12. The surface roughness may be determined in accordance with the surface roughness specifications set forth in ISO Standard 1302, in particular ISO Standard 1302:1992. The surface roughness of the opposing end sections may be produced by any suitable manufacturing or machining process, including but not limited to abrasion, casting, coating, cutting, etching, plastic deformation, sintering, wear, and erosion.

[0020] In an arrangement where the first and second sealing elements comprise opposing end sections of the tubular heater, the heater assembly may further comprise a third sealing element configured to further seal the first heater housing to the tubular heater. The heater assembly may further comprise a fourth sealing element configured to further seal the second heater housing to the tubular heater. Advantageously, this arrangement helps provide a further degree of sealing to the airflow path.

[0021] The third sealing element may include an annular seal. The third sealing element may be arranged between the inner surface of the first heater housing and the outer surface of the tubular heater. Advantageously, in this arrangement, the third sealing element is placed on the side of the tubular heater opposite to where the airflow path passes, so that the tubular heater acts as a physical barrier between the third sealing element and the airflow path.

[0022] The fourth sealing element may comprise an annular seal. The fourth sealing element may be arranged between the inner surface of the second heater housing and the outer surface of the tubular heater. Advantageously, in this arrangement, the fourth sealing element is placed on the side of the tubular heater opposite to where the airflow path passes, so that the tubular heater acts as a physical barrier between the fourth sealing element and the airflow path.

[0023] In one example, the tubular heater may be enclosed by the first and second heater housings.Advantageously, this arrangement may help to inhibit leakage of aerosol from the airflow path into the aerosol generating device.

[0024] In another example, the heater assembly may further include a heater sleeve surrounding at least a portion of the tubular heater, the heater sleeve being disposed between the first heater housing and the second heater housing.The heater sleeve may help inhibit leakage of aerosol from the airflow path into the aerosol generating device.

[0025] The first sealing element may engage the inner surface of the first heater housing, the outer surface of the tubular heater and the inner surface or end surface of the heater sleeve. This arrangement may help provide a sealing engagement between the first heater housing, the tubular heater and the heater sleeve to seal the airflow path.

[0026] The second sealing element can engage the inner surface of the second heater housing, the outer surface of the tubular heater and the inner surface or end surface of the heater sleeve. This arrangement can help provide a sealing joint between the second heater housing, the tubular heater and the heater sleeve to seal the airflow path.

[0027] The first and second heater shells can be radially spaced apart from the tubular heater to define a hollow air space surrounding the tubular heater. Advantageously, the hollow air space helps to thermally insulate the tubular heater, which helps to reduce heat loss from the tubular heater and also helps to reduce heat transfer to the exterior of the heater assembly.

[0028] The first and second heater housings may be made of any suitable material. Preferably, the first and second heater housings are made of a heat resistant plastic that can withstand temperatures of at least 250 degrees Celsius, preferably at least 300 degrees Celsius, and more preferably at least 350 degrees Celsius. In one example, the first and second heater housings may be made of polyetheretherketone (PEEK). This material is a good thermal insulator and helps reduce heat transfer from the heater assembly.

[0029] The diameter of the tubular heater at the first end of the tubular heater may be greater than the diameter along the length of the tubular heater. The diameter of the tubular heater at the second end of the tubular heater may be greater than the diameter along the length of the tubular heater. The diameter of the tubular heater at each end of the tubular heater may be greater than the diameter of the tubular heater in the area between the two ends of the tubular heater. The advantage of making the diameter of one or both ends of the tubular heater greater than the diameter of the tubular heater along the length of the tubular heater (e.g., the diameter in the area between the two ends of the tubular heater) is that it allows for greater manufacturing tolerances for the tubular heater and other components of the heater assembly. This can facilitate assembly of the heater assembly and also reduce the number of machining or finishing steps required during manufacture of the tubular heater.

[0030] Another advantage of having the ends of the tubular heater have a larger diameter than the rest of the tubular heater is that the inner diameter at one or both ends of the tubular heater will be larger than the inner diameter of the airflow path in the other components of the heater assembly to which the tubular heater is engaged (e.g., the first and second heater housings). This helps to avoid the end surface of the tubular heater protruding or intruding into the interior space of the airflow path, which could potentially cause damage to the aerosol-generating article when the aerosol-generating article is received into the tubular heater.

[0031] The outer diameter of one or both ends of the tubular heater may be up to 40% larger, preferably up to 35% larger, more preferably up to 30% larger, even more preferably up to 27% larger than the outer diameter of the portion of the tubular heater between the two ends of the tubular heater. The outer diameter of one or both ends of the tubular heater may be 10% to 40% larger, 15% to 35% larger, 20% to 30% larger, or 25% to 30% larger than the outer diameter of the portion of the tubular heater between the two ends of the tubular heater.

[0032] One or both ends of the tubular heater may have an outer diameter between about 7.6 mm and about 10.7 mm, preferably between about 9.0 mm and about 10.0 mm, and more preferably about 9.7 mm. The portion of the tubular heater between the two ends of the tubular heater may have an outer diameter between about 6.5 mm and about 8.0 mm, preferably between about 7.0 mm and about 8.0 mm, and more preferably about 7.6 mm.

[0033] The inner diameter of the tubular heater between the two ends of the tubular heater may substantially correspond to or be substantially equal to the outer diameter of the aerosol-generating article. In some embodiments, the inner diameter of the tubular heater may be slightly smaller than the outer diameter of the aerosol-generating article so that the aerosol-generating article is compressed in the tubular heater. For example, the outer diameter of the aerosol-generating article may be about 7.4 mm, and the inner diameter of the tubular heater may be about 7.3 mm. The length of the tubular heater may substantially correspond to or be substantially equal to the length of the aerosol-forming substrate disposed in the aerosol-generating article.

[0034] A portion of the first end of the tubular heater may be expanded or funnel-shaped. A portion of the second end of the tubular heater may be expanded or funnel-shaped. A portion of each end of the tubular heater may be expanded or funnel-shaped. The axial length of each portion of each end of the tubular heater that is expanded or funnel-shaped may be between 3.5% and 15% of the total length of the tubular heater, preferably between 5% and 10% of the total length of the tubular heater, and more preferably about 8% of the total length of the tubular heater. The expansion or funnel-shaped one or more end portions of the tubular heater may be arranged at an angle between 30 and 60 degrees, between 40 and 50 degrees, or at an angle of about 45 degrees relative to the longitudinal axis of the tubular heater or heater assembly.

[0035] Advantageously, the expanded or funnel-shaped portion of the tubular heater is a convenient way of providing a tubular heater having a diameter at one or both ends that is larger than the diameter of the tubular heater in the region between the two ends of the tubular heater. Furthermore, the expanded or funnel-shaped portion of the tubular heater provides a smooth transition between the larger diameter and the smaller diameter, which facilitates insertion of the aerosol-generating article into the tubular heater. Additionally, the expanded or funnel-shaped portion of the tubular heater provides an improved seal to the airflow path.

[0036] In an arrangement in which the tubular heater has an expanded or funnel-shaped end portion and in which the first and second sealing elements comprise opposite end sections of the tubular heater, the first and second sealing elements may comprise an elongated section at each end of the tubular heater extending in a direction parallel to the longitudinal axis of the tubular heater. Each elongated section of the tubular heater may have a length of between 1 mm and 2 mm and preferably about 1.5 mm. The length of each elongated section may be between 3.5% and 15% of the total length of the tubular heater, preferably between 7% and 12% of the total length of the tubular heater and more preferably about 9% of the total length of the tubular heater.

[0037] The tubular heater may be made of any suitable material including, but not limited to, ceramic or metal or metal alloy. An example of a suitable material is stainless steel.

[0038] The heater assembly may include at least one electric heating element for heating the aerosol-forming substrate. The heater assembly may include a plurality of electric heating elements. The one or more electric heating elements may be arranged around the outer surface of the tubular heater or define the outer surface of the tubular heater. The one or more electric heating elements may be arranged around the inner surface of the tubular heater or define the inner surface of the tubular heater. The one or more electric heating elements may be part of the tubular heater or be integral with the tubular heater.

[0039] One or more electric heating elements may include a resistive material. Suitable resistive materials include, but are not limited to, semiconductors such as doped ceramics, electrically "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, 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, gold-containing alloys, iron-containing alloys, and superalloys based on nickel, iron, cobalt, stainless steel, TimetalTM, KanthalTM, and other iron-chromium-aluminum alloys, and iron-manganese-aluminum-based alloys. In the composite material, the resistive material may optionally be embedded in, encapsulated by or coated by an insulating material or vice versa, depending on the kinetics of energy transfer and the desired external physicochemical properties.

[0040] One or more heating elements may be formed using a metal or metal alloy having a defined relationship between temperature and resistivity. A heating element formed in this manner may be used to heat and monitor the temperature of the heating element during operation.

[0041] The heating element may be deposited in or on a rigid carrier material or substrate. The heating element may be deposited in or on a flexible carrier material or substrate. The heating element may be formed as a track on a suitable insulating material such as ceramic or glass or a polyimide film. The heating element may be sandwiched between two insulating materials.

[0042] The heater assembly may comprise a flexible heating element arranged around or defining an outer surface of the tubular heater.The flexible heating element may have a length substantially equal to the length of an aerosol-forming substrate provided in the aerosol-generating article.

[0043] The tubular heater may be configured to receive at least a portion of an aerosol-generating article (as defined below).

[0044] According to an example of the present disclosure, an aerosol generating device is provided. The aerosol generating device may include a heater assembly according to any of the heater assemblies described above. The aerosol generating device may include a power supply device for supplying power to the heater assembly.

[0045] According to an example of the present disclosure, an aerosol generating device is provided. The aerosol generating device comprises a heater assembly according to any one of the heater assemblies described above. The aerosol generating device comprises a power supply device for supplying power to the heater assembly.

[0046] The power supply device can be any suitable power supply device, such as a DC voltage source. In one embodiment, the power supply device is a lithium-ion battery. Alternatively, the power supply device can be a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery, such as a lithium cobalt, lithium iron phosphate, or lithium polymer battery.

[0047] The aerosol generating device is preferably a handheld aerosol generating device that is comfortably held by a user between the fingers of a single hand.

[0048] The aerosol generating device may further comprise a control circuit configured to control the supply of power to the heater assembly. The control circuit may comprise a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller or an application specific integrated chip (ASIC) or other electronic circuit capable of providing control. The control circuit may comprise additional electronic components. For example, in some embodiments, the control circuit may comprise any one of a sensor, a switch, a display element. Power may be supplied to the heater assembly continuously after the device is activated, or may be supplied intermittently, such as on a puff-by-puff basis. Power may be supplied to the heater assembly in the form of current pulses, for example by means of pulse width modulation (PWM).

[0049] The aerosol generating device may include a device housing. The device housing may accommodate a heater assembly, a power supply, and a control circuit. The housing may include an opening for receiving an aerosol generating article. The opening may be connected to an aerosol outlet of a second heater housing of the heater assembly to allow the aerosol generating article to be inserted into the tubular heater. The housing may include an air inlet. The air inlet may be connected to an air inlet of a first heater housing of the heater assembly.

[0050] The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK) and polyethylene. Preferably, the material is lightweight and non-brittle.

[0051] According to an example of the present disclosure, an aerosol generating system is provided. The aerosol generating system may include an aerosol generating device according to any of the aerosol generating devices described above. The aerosol generating system may include an aerosol generating article, the aerosol generating article including an aerosol-forming substrate.

[0052] According to an example of the present disclosure, an aerosol generating system is provided. The aerosol generating system comprises an aerosol generating device according to any of the aerosol generating devices described above. The aerosol generating system comprises an aerosol generating article, the aerosol generating article comprising an aerosol-forming substrate.

[0053] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate that releases volatile compounds that can form an aerosol when heated in an aerosol-generating device. The aerosol-generating article is separate from the aerosol-generating device for heating the aerosol-generating article and is configured for combination with the aerosol-generating device.

[0054] The aerosol-generating article may be substantially cylindrical in shape. The aerosol-generating article may be substantially elongate. The aerosol-forming substrate may be substantially cylindrical in shape. The aerosol-forming substrate may be substantially elongate.

[0055] The aerosol generating article may have a total length between about 30 mm and about 100 mm. The aerosol generating article may have an outer diameter between about 5 mm and about 12 mm. The aerosol forming substrate may have a length between about 10 mm and about 18 mm. In addition, the diameter of the aerosol forming substrate may be between about 5 mm and about 12 mm. The aerosol generating article may include a filter filter segment. The filter filter segment may be located at the downstream end of the aerosol generating article. The filter filter segment may be a cellulose acetate filter filter segment. The length of the filter filter segment is about 7 mm in one embodiment, but may have a length between about 5 mm and about 12 mm.

[0056] The terms "upstream", "downstream", "proximal" and "distal" are used to describe the relative positions of components or parts of components of aerosol generating devices and aerosol generating articles. Aerosol generating articles and aerosol generating devices according to the present disclosure have a proximal end and have a relative distal end, and in use, the aerosol leaves the article or device through the proximal end for delivery to a user. The proximal end of the aerosol generating article and the aerosol generating device may also be referred to as the mouth end. In use, the user draws on the proximal end of the aerosol generating article to inhale the aerosol generated by the aerosol generating article or the aerosol generating device. The terms upstream and downstream are relative to the direction in which the aerosol moves through the aerosol generating article or the aerosol generating device when the user draws on the proximal end of the aerosol generating article. The proximal end of the aerosol generating article is downstream of the distal end of the aerosol generating article. The proximal end of the aerosol-generating article may also be referred to as the downstream end of the aerosol-generating article, and the distal end of the aerosol-generating article may also be referred to as the upstream end of the aerosol-generating article.

[0057] In one embodiment, the aerosol generating article may have a total length of about 45 mm. The aerosol generating article may have an outer diameter of about 7.3 mm, but may have an outer diameter between about 7.0 mm and about 7.4 mm. In addition, the aerosol forming substrate may have a length of about 12 mm. Alternatively, the aerosol forming substrate may have a length of about 16 mm. The aerosol generating article may include an outer wrapper. In addition, the aerosol generating article may include a partition between the aerosol forming substrate and the filter segment. The partition may be about 21 mm or about 26 mm, but may be in the range of about 5 mm to about 28 mm. The partition may be provided by a hollow tube. The hollow tube may be made of cardboard or cellulose acetate.

[0058] Aerosol formation substrate can be a solid aerosol formation substrate.Alternately, aerosol formation substrate can include both solid components and liquid components.Aerosol formation substrate can include tobacco-containing material, and tobacco-containing material is included in the volatile tobacco flavor compounds released from substrate when heated.Alternately, aerosol formation substrate can include non-tobacco material.Aerosol formation substrate can also include aerosol forming agent.The example of suitable aerosol forming agent is glycerol and propylene glycol.

[0059] If aerosol formation substrate is solid aerosol formation substrate, then the solid aerosol formation substrate can include one or more of the following: powder, granule, pellet, fragment, thin strip, strip or sheet, which contains one or more of herbaceous plant leaf, tobacco leaf, tobacco rib material, reconstituted tobacco, homogenized tobacco, extruded tobacco and expanded tobacco. Solid aerosol formation substrate can be in loose form, or can be provided in a suitable container or tube. Alternatively, solid aerosol formation substrate can contain additional tobacco or non-tobacco volatile aroma compounds released when substrate is heated. Solid aerosol formation substrate can also contain capsule, and the capsule for example includes additional tobacco or non-tobacco volatile aroma compounds, and such capsule can melt during the heating period of solid aerosol formation substrate.

[0060] As used herein, homogenized tobacco refers to the material formed by agglomerating particle tobacco.Homogenized tobacco can be in the form of sheet material.The homogenized tobacco material can have an aerosol forming agent content greater than 5% by dry weight.Alternately, the homogenized tobacco material can have an aerosol forming agent content between 5 % by weight and 30 % by weight by dry weight.The sheet material of the homogenized tobacco material can be formed by agglomerating particle tobacco, and the particle tobacco is obtained by grinding or otherwise pulverizing one or both of tobacco leaf blade and tobacco leaf stem.Alternately or in addition, the sheet material of the homogenized tobacco material can include one or more of tobacco dust, broken cigarette and other particle tobacco byproducts formed during the processing, operation and transportation of (for example) tobacco. The sheet of homogenized tobacco material may include one or more inherent binders that are endogenous binders to tobacco, one or more external binders that are exogenous binders to tobacco, or combinations thereof to help agglomerate the particulate tobacco; alternatively or in addition, the sheet of homogenized tobacco material may include other additives, including but not limited to tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorings, fillers, aqueous solvents and non-aqueous solvents, and combinations thereof.

[0061] In a particularly preferred embodiment, the aerosol-forming substrate comprises a gathered curled sheet of homogenized tobacco material. As used herein, the term "curled sheet" means a sheet with a plurality of substantially parallel ridges or folds. Preferably, when the aerosol-generating article has been assembled, the substantially parallel ridges or folds extend along or parallel to the longitudinal axis of the aerosol-generating article. This advantageously promotes the gathering of the curled sheet of homogenized tobacco material to form an aerosol-forming substrate. However, it should be understood that the curled sheet of the homogenized tobacco material included in the aerosol-generating article can alternatively or additionally have a plurality of substantially parallel ridges or folds that are arranged at an acute angle or an obtuse angle with the longitudinal axis of the aerosol-generating article when the aerosol-generating article has been assembled. In certain embodiments, the aerosol-forming substrate can comprise a gathered sheet of homogenized tobacco material, and the gathered sheet is substantially uniformly textured on substantially its entire surface. For example, the aerosol-forming substrate may comprise a gathered crimped sheet of homogenised tobacco material comprising a plurality of substantially parallel ridges or corrugations that are substantially evenly spaced across the width of the sheet.

[0062] Alternatively, solid aerosol formation matrix can be arranged on the heat-stable carrier or be embedded in the heat-stable carrier.Carrier can take the form of powder, particle, pellet, fragment, thin strip, strip or sheet.Alternately, carrier can be a tubular carrier, on its inner surface or on its outer surface or on its inner surface and outer surface, be deposited with a solid matrix thin layer.This type of tubular carrier can be formed by, for example, paper or paper-like material, nonwoven carbon fiber mat, low-quality open-net metal wire mesh or perforated metal foil or any other heat-stable polymer matrix.

[0063] The solid aerosol-forming substrate may be deposited 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 uneven flavor delivery during use.

[0064] Although solid aerosol-forming substrates are referred to above, it will be clear to those skilled in the art that other forms of aerosol-forming substrates can be used with other embodiments. For example, the aerosol-forming substrate can be a liquid aerosol-forming substrate. If a liquid aerosol-forming substrate is provided, the aerosol-generating device preferably includes a device for holding a liquid. For example, the liquid aerosol-forming substrate can be held in a container or a liquid storage portion. Alternatively or in addition, the liquid aerosol-forming substrate can be sucked into a porous carrier material. The porous carrier material can be made of any suitable absorbent rod or absorbent, for example, foamed metal or plastic material, polypropylene, polyester, nylon fiber or ceramic. Before using the aerosol-generating device, the liquid aerosol-forming substrate can be held in the porous carrier material, or alternatively, the liquid aerosol-forming substrate material can be released into the porous carrier material during use or shortly before use. For example, the liquid aerosol-forming substrate can be arranged in a capsule. The shell of the capsule preferably melts when heated and releases the liquid aerosol-forming substrate into the porous carrier material. The capsule may optionally contain a solid in combination with a liquid.

[0065] Alternatively, the carrier may be a nonwoven fabric or fiber bundle that has included a tobacco component. The nonwoven fabric or fiber bundle may include, for example, carbon fibers, natural cellulose fibers, or cellulose derivative fibers.

[0066] Features described with respect to one of the above examples may also be applied to other examples of the present disclosure.

[0067] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0068] Example Ex1: A heater assembly for an aerosol generating device, the heater assembly comprising: a heating chamber for heating an aerosol-forming substrate; an air inlet and an aerosol outlet; wherein an air flow path extends from the air inlet through the heater assembly to the aerosol outlet, the air flow path passing through the heating chamber.

[0069] Example Ex2: The heater assembly of Example Ex1, further comprising a first heater housing, wherein the first heater housing comprises the air inlet.

[0070] Example Ex3: The heater assembly according to any one of Examples Ex1 or Ex2, further comprising a second heater housing, wherein the second heater housing comprises the aerosol outlet.

[0071] Example Ex4: The heater assembly of any of Examples Ex1 to Ex3, further comprising a first sealing element configured to seal the first heater housing to the heating chamber.

[0072] Example Ex5: The heater assembly of any of Examples Ex1 to Ex4, further comprising a second sealing element configured to seal the second heater housing to the heating chamber.

[0073] Example Ex6: The heater assembly of Example Ex5, wherein the first sealing element and the second sealing element are separated from the air flow path.

[0074] Example Ex7: The heater assembly of any one of Examples Ex3 to Ex6, wherein the airflow path passes through the first heater housing, the heating chamber, and the second heater housing.

[0075] Example Ex8: The heater assembly of any of Examples Ex4 to Ex7, wherein the first sealing element comprises an annular seal and is disposed between an inner surface of the first heater housing and an outer surface of the heating chamber.

[0076] Example Ex9: The heater assembly of any one of Examples Ex5 to Ex8, wherein the second sealing element comprises an annular seal and is disposed between an inner surface of the second heater housing and an outer surface of the heating chamber.

[0077] Example Ex10: A heater assembly according to any one of Examples Ex5 to Ex9, wherein at least one of the first sealing element and the second sealing element is arranged in a groove or a recess formed in an inner surface of a corresponding one of the first heater housing and the second heater housing.

[0078] Example Ex11: The heater assembly according to any one of Examples Ex2 to Ex10, wherein the first heater housing includes a holder for holding the heating chamber, the airflow path passing through the holder.

[0079] Example Ex12: The heater assembly of Example Ex11, wherein the first sealing element is disposed between the retainer and an outer surface of the heating chamber.

[0080] Example Ex13: The heater assembly according to Example Ex5, wherein the first sealing element and the second sealing element include opposite end sections of the heating chamber, and the opposite end sections are fixed to the inner surface of the first heater housing and the second heater housing in a sealing joint.

[0081] Example Ex14: The heater assembly of Example Ex13, wherein the opposing end sections of the heating chamber are secured in sealing engagement within grooves or recesses formed in the inner surfaces of the first and second heater housings.

[0082] Example Ex15: The heater assembly of Example Ex13, wherein opposite end sections of the heating chamber are embedded in the inner surfaces of the first and second heater housings.

[0083] Example Ex16: The heater assembly according to any one of Examples Ex13 to Ex15, wherein the opposing end segments extend in a direction parallel to the longitudinal axis of the heating chamber by a length between 5% and 15% of the total length of the heating chamber.

[0084] Example Ex17: The heater assembly of Example Ex13, wherein the opposing end sections of the heating chamber have a surface finish having an ISO roughness value in the range of N9 to N12.

[0085] Example Ex18: The heater assembly according to any one of Examples Ex13 to Ex17, further comprising a third sealing element configured to further seal the first heater housing to the heating chamber.

[0086] Example Ex19: The heater assembly according to any one of Examples Ex13 to Ex18, further comprising a fourth sealing element configured to further seal the second heater housing to the heating chamber.

[0087] Example Ex20: The heater assembly of Example Ex18 or Ex19, wherein the third sealing element comprises an annular seal and is disposed between an inner surface of the first heater housing and an outer surface of the heating chamber.

[0088] Example Ex21: The heater assembly of any one of Examples Ex18 to Ex20, wherein the fourth sealing element comprises an annular seal and is disposed between an inner surface of the second heater housing and an outer surface of the heating chamber.

[0089] Example Ex22: The heater assembly of any one of Examples Ex3 to Ex21, wherein the heating chamber is enclosed by the first heater housing and the second heater housing.

[0090] Example Ex23: The heater assembly according to any one of Examples Ex3 to Ex21, further comprising a heater sleeve surrounding at least a portion of the heating chamber, the heater sleeve being arranged between the first heater housing and the second heater housing.

[0091] Example Ex24: The heater assembly of Example Ex23, wherein the first sealing element engages an inner surface of the first heater housing, an outer surface of the heating chamber, and an inner surface or an end surface of the heater sleeve.

[0092] Example Ex25: The heater assembly of Example Ex23 or Ex24, wherein the second sealing element engages an inner surface of the second heater housing, an outer surface of the heating chamber, and an inner surface or an end surface of the heater sleeve.

[0093] Example Ex26: The heater assembly according to any one of Examples Ex1 to Ex25, wherein a diameter of the heating chamber at each end of the heating chamber is larger than a diameter of the heating chamber in a region between the two ends of the heating chamber.

[0094] Example Ex27: A heater assembly according to Example Ex26, wherein a portion of each end of the heating chamber is flared or funnel-shaped.

[0095] Example Ex28: A heater assembly according to Example Ex27, wherein the axial length of the flared or funnel-shaped end of the heating chamber is between 5% and 15% of the total length of the heating chamber.

[0096] Example Ex29: A heater assembly according to any one of Ex1 to Ex28, wherein the heating chamber includes a tubular heater.

[0097] Example Ex30: An aerosol generating device comprising: a heater assembly according to any one of Examples Ex1 to Ex29; and a power supply device for supplying power to the heater assembly.

[0098] Example Ex31: An aerosol generating system comprising: an aerosol generating device according to Example Ex30; and an aerosol generating article comprising an aerosol-forming substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Several examples will now be further described with reference to the accompanying drawings, in which:

[0100] Figure 1 is a schematic cross-sectional view showing the interior of an aerosol-generating device and an aerosol-generating article received in the aerosol-generating device according to an example of the present disclosure.

[0101] Figure 2 is a cross-sectional view of a portion of an aerosol generating device having a heater assembly according to an example of the present disclosure.

[0102] Figure 3 for Figure 2 An enlarged schematic cross-sectional view of the sealing arrangement marked A in FIG.

[0103] Figure 4 is a cross-sectional view of a heater assembly according to another example of the present disclosure.

[0104] Figure 5 for Figure 4 An enlarged schematic cross-sectional view of the sealing arrangement marked E in FIG.

[0105] Figure 6 is a side view of an exemplary tubular heater for use in a heater assembly according to the present disclosure.

[0106] Figure 7 is a cross-sectional view of a heater assembly according to another example of the present disclosure.

[0107] Figure 8 is a side view of another exemplary tubular heater for use in a heater assembly according to the present disclosure.

[0108] Fig. 9 is a cross-sectional view of a heater assembly according to another example of the present disclosure. DETAILED DESCRIPTION

[0109] refer to Figure 1 , which shows a schematic cross-sectional view of the interior of the aerosol generating device 100 and the aerosol generating article 200 received in the aerosol generating device 100. The aerosol generating device 100 and the aerosol generating article 200 together form an aerosol generating system. Figure 1 In the figure, the aerosol generating device 100 is shown in a simplified manner. In particular, the elements of the aerosol generating device 100 are not drawn to scale. In addition, elements that are not relevant to the understanding of the aerosol generating device 100 are omitted.

[0110] The aerosol generating device 100 comprises a housing 102, which houses a heater assembly 10, a power supply 103 and a control circuit 105. The heater assembly 10 comprises a first heater housing 12, a second heater housing 14 and a tubular heater 16 for heating an aerosol-forming substrate. The tubular heater 16 at least partially defines a cavity for receiving a portion of the aerosol generating article 200, and has a flexible heating element (not shown) arranged around its outer surface for heating the tubular heater 16 and in turn heating the aerosol generating article 200. The power supply 103 comprises a battery, and in this example, it is a rechargeable lithium-ion battery. The control circuit 105 is connected to both the power supply 103 and the heating element (not shown), and controls the supply of electrical energy from the power supply 103 to the heating element to adjust the temperature of the heating element.

[0111] The first heater housing 12 is attached to the second heater housing 14 and together surround or enclose the tubular heater 16 to inhibit aerosol generated within the tubular heater 16 from leaking into the aerosol generating device 100. The heater assembly 10 also includes a first sealing element (now a sealing element) configured to seal the first heater housing 12 to the tubular heater 16. Figure 1 ) and a second sealing element (shown in FIG. 1 ) configured to seal the second heater housing 14 to the tubular heater 16 Figure 1 ). The first and second sealing elements help to further inhibit leakage of aerosol from the tubular heater 16 into the aerosol generating device 100, and various sealing arrangements will be discussed in more detail below.

[0112] The first heater housing 12 comprises an air channel section 12a and a support section 12b. The air channel section 12a extends from the distal end of the aerosol generating device 100 to the support section 12b parallel to the longitudinal axis of the aerosol generating device 100. The support section 12b is configured to support the tubular heater 16 and is attached to the second heater housing 14. An air inlet 18 is arranged at the distal end of the air channel section 12a of the first heater housing 12. The air inlet 18 is connected to an opening 106 formed at the distal end of the housing 102. Air can enter the aerosol generating device 10 via the opening 106 and the air inlet 18, and flow to the tubular heater 16 via the air channel section 12a.

[0113] The aerosol outlet 20 is arranged at the proximal end of the second heater housing 14. The aerosol outlet 20 is connected to an opening 104 formed at the proximal end of the housing 102. The opening 104 is also connected to the interior of the tubular heater 16, and the aerosol generating article 200 can be received into the tubular heater 16 via the opening 104. The aerosol generating article 200 is longer than the cavity inside the aerosol generating device 100 that is partially defined by the tubular heater 16, and therefore the proximal end or mouth end of the aerosol generating article 200 protrudes from the aerosol generating device 100 when the aerosol generating article 200 is fully inserted.

[0114] Airflow path (by Figure 1 1 (indicated by the plurality of arrows 22 in FIG. 1 ) extend from the air inlet 18 through the heater assembly 10 to the aerosol outlet 20, and through the first heater housing 12, the tubular heater 16, and the second heater housing 14. The aerosol leaves the heater assembly 10 via the aerosol outlet 20 connected to the opening 104 in the housing 102. However, it should be understood that in use, when the aerosol generating article is received in the aerosol generating device 100, the aerosol mostly leaves the heater assembly 10 and the aerosol generating device 100 via the aerosol generating article 200.

[0115] In this example, the aerosol generating article 200 comprises an end plug 202, an aerosol forming substrate 204, a hollow tube 206 and a mouthpiece filter 208. Each of the above-mentioned components of the aerosol generating article 100 is a substantially cylindrical element, each cylindrical element having substantially the same diameter. The components are arranged in sequence in an adjacent coaxial alignment and are defined by an outer wrapper 210 to form a cylindrical strip. The aerosol forming substrate 204 is a tobacco strip or rod comprising a gathered sheet of curled homogenized tobacco material defined by a wrapper (not shown). The curled sheet of homogenized tobacco material comprises glycerol as an aerosol forming agent. The end plug 202 and the mouthpiece filter 208 are formed by cellulose acetate fibers. The aerosol-forming substrate 204 is arranged in the aerosol-generating article 200 such that when the aerosol-generating article 200 is fully inserted into the aerosol-generating device 100, the aerosol-forming substrate 204 is located within the tubular heater 16 to heat the aerosol-forming substrate 204. It will be appreciated that other aerosol-generating articles having different components or different arrangements of components may also be used.

[0116] The aerosol generating device 100 may also include: a sensor (not shown) for detecting the presence of the aerosol generating article 200; a user interface (not shown), such as a button, for activating the heating element; and a display or indicator (not shown) for presenting information to the user (e.g., remaining battery power, heating status, and error messages).

[0117] In use, such as Figure 1 As shown in , the user inserts the aerosol generating article 200 into the aerosol generating device 100. The user then starts the heating cycle by activating the aerosol generating device 100 (e.g., by pressing a switch to turn the device on). In response, the control circuit 105 controls the supply of power from the power supply 103 to the heating element (not shown) to heat the heating element, which in turn heats the tubular heater 16. During the heating cycle, the heating element heats the tubular heater 16 to a predetermined temperature or a predetermined temperature range according to a temperature curve. The heating cycle can last for about 6 minutes. The heat from the tubular heater 16 is transferred to the aerosol-forming substrate 204, which releases volatile compounds from the aerosol-forming substrate 204. The volatile compounds form an aerosol in the aerosolization chamber formed by the hollow tube 206. During the heating cycle, the user places the mouthpiece filter 208 of the aerosol generating article 200 between the lips of his mouth and draws or inhales on the mouthpiece filter 208. This creates a pressure drop within the aerosol-generating article 200, which is in fluid communication with the air inlet 18 and the opening 106 of the aerosol-generating device 100 via the air channel section 12a of the first heater housing 12. The pressure drop causes air to be drawn into the aerosol-generating device 100 via the air inlet 18 and to flow via the air channel section 12a to the aerosol-generating article 200. The air passes through the aerosol-generating article 200, entraining the aerosol generated from the aerosol-forming substrate 204, which is then drawn through the mouthpiece filter 208 into the mouth of the user.

[0118] Figure 2 is a cross-sectional view of a portion of an aerosol generating device 300 having a heater assembly 310 according to an example of the present disclosure. Figure 2 The aerosol generating device 300 has Figure 1 The heater assembly 310 is of a similar general construction to the aerosol generating device 100 of the present invention. The heater assembly 310 comprises a first heater housing 312, a second heater housing 314 and a tubular heater 316 for heating an aerosol-forming substrate received in the tubular heater 316. The tubular heater 316 has a flexible heating element 317 arranged around its outer surface for heating the tubular heater 316.

[0119] exist Figure 2In the exemplary heater assembly 310 of FIG. 3 , the first heater housing includes a tube holder 319 for holding a tubular heater 316. The tube holder 319 helps to position the tubular heater 316 within the heater assembly 310. A holder air channel 321 extends axially through the tube holder 319 to allow air to flow through the tube holder 319. The first heater housing 312 is attached to the second heater housing 314, and the first heater housing 312 and the second heater housing 314 together enclose the tubular heater 316 and the tube holder 319 to inhibit the aerosol generated within the tubular heater 316 from leaking into the aerosol generating device 300. The wall of the second heater housing 314 is radially spaced from the tubular heater 316 to define an air space 323 around the tubular heater 316. The air space 323 helps to thermally insulate the tubular heater 316, which helps to reduce heat loss from the tubular heater 316 and also helps to reduce heat transfer to the outside of the heater assembly 310 and the aerosol generating device 300.

[0120] The first heater housing 312 includes an air channel section 312a and a support section 312b. The support section 312b is configured to be attached to the second heater housing 314. An air inlet (not shown) is arranged at the distal end of the air channel section 12a. The aerosol outlet 320 is arranged at the proximal end of the second heater housing 314 and is connected to an opening 304 formed at the proximal end of the housing 302 of the aerosol generating device 300. An aerosol generating article (not shown) can be received into the tubular heater 316 via the opening 304. The airflow path (composed of Figure 2 The plurality of arrows 322 in FIG. 3 extend from an air inlet (not shown) through the heater assembly 310 to the aerosol outlet 320 and through the first heater housing 312 including the tube holder 319 , the tubular heater 316 , and the second heater housing 314 .

[0121] The heater assembly 310 also includes a first sealing element 326 that seals the tubular heater 316 to the tube retainer 319 of the first heater housing 312. The first sealing element 326 includes an O-ring that confines the tubular heater 316 near the distal end of the tubular heater 316. The O-ring contacts the outer surface of the tubular heater 316 and the tube retainer 319 of the first heater housing 312 to provide a seal between the two components that inhibits aerosol from leaking from the tubular heater 316 into the air space 323 surrounding the tubular heater 316 or other portions of the aerosol generating device 300. The area sealed by the first sealing element is Figure 2 Indicated by circles C and D.

[0122] The heater assembly 310 also includes a second sealing element 324 that seals the tubular heater 316 to the second heater housing 314. The second sealing element 324 includes an O-ring that circumscribes the tubular heater 316 near the proximal end of the tubular heater 316. The O-ring contacts the outer surface of the tubular heater 316 and the inner surface of the second heater housing 314 to provide a seal between the two components that inhibits aerosol from leaking from the tubular heater 316 into the air space 323 surrounding the tubular heater 316 or other portions of the aerosol generating device 300. The area sealed by the second sealing element is Figure 2 In the figure, circles A and B are shown.

[0123] The O-rings of the first sealing element 326 and the second sealing element 324 are preferably formed of a perfluoroelastomer such as FFKM due to the elastic deformability, temperature resistance and low toxicity of the perfluoroelastomer. Suitable O-rings are Kalrez™ O-rings manufactured by DuPont. However, other suitable O-rings and materials may be used.

[0124] Figure 3 The second sealing element 324 seals Figure 2 The tubular heater 316 has an expanded proximal end 316a, as shown below with respect to Figure 6 The second heater housing 314 includes a recess or groove 328 for receiving the expanded proximal end 316a of the tubular heater 316. The second sealing element 324 is also located in the groove 328 and engages the inner surface of the groove 328 and the outer surface of the tubular heater 316 to inhibit aerosol from leaking from the tubular heater 316 to the air space 323 between the tubular heater 316 and the second heater housing 314. The second sealing element 324 is placed on the side of the tubular heater 316 opposite to where the airflow path 322 passes through the tubular heater 316, so that the wall of the tubular heater 316 acts as a physical barrier between the second sealing element 324 and the airflow path, which keeps the second sealing element separated from the airflow path 322.

[0125] As mentioned above Figure 2 As described, the second sealing element comprises an O-ring and defines the outer surface of the tubular heater 316 in the region of the flared proximal end 316a, thereby Figure 2 In the circular area marked B, Figure 3 At the distal end of the tubular heater 316, i.e., at Figure 2 In the circular areas marked as C and D in FIG. 1 , there are also provided in the tube holder 319 of the first heater housing 312 the same as Figure 3A groove arrangement similar to the groove arrangement shown in .

[0126] Figure 4 is a cross-sectional view of a heater assembly 410 according to another example of the present disclosure. Figure 4 The heater assembly 410 has Figure 1 and 2 The heater assembly 410 is of similar general construction to the heater assembly 10 and 310. The heater assembly 410 includes a first heater housing 412, a second heater housing 414, and a tubular heater 416 for heating an aerosol-forming substrate received within the tubular heater 416. Figure 4 In the example of FIG. 4 , the first heater housing 412 is not directly connected to the second heater housing 414, but the heater sleeve 430 is arranged between the first heater housing 412 and the second heater housing 414. The heater sleeve 430 circumferentially surrounds substantially the entire length of the tubular heater 416, except for the two ends of the tubular heater 416 located within the first heater housing 412 and the second heater housing 414.

[0127] In addition, Figure 4 In the example of FIG. 4 , the tubular heater 416 is supported directly on top of the first heater housing 412, but a tube holder may be used if necessary, such as Figure 2 In the example of Figure 4 The air inlet 418 at the distal end of the first heater housing 312 (indicated by multiple arrows 422 in the figure) extends through the heater assembly 410 to the aerosol outlet 420 at the proximal end of the second heater housing 414, and passes through the first heater housing 412, the tubular heater 416 and the second heater housing 414.

[0128] The heater assembly 410 also includes a first sealing element 426 that seals the tubular heater 416 to the first heater housing 412 and the heater sleeve 430. The first sealing element 326 includes an O-ring that circumscribes the tubular heater 416 near the distal end of the tubular heater 416. The O-ring contacts the outer surface of the tubular heater 416, the inner surface of the first heater housing 412, and the distal end surface of the heater sleeve 430 to provide a seal between these components that inhibits leakage of aerosol from the heater assembly 410 into surrounding portions of the aerosol generating device 300.

[0129] The heater assembly 410 also includes a second sealing element 424 that seals the tubular heater 416 to the second heater housing 414 and the heater sleeve 430. The second sealing element 324 includes an O-ring that circumscribes the tubular heater 416 near the proximal end of the tubular heater 416. The O-ring contacts the outer surface of the tubular heater 416, the inner surface of the second heater housing 414, and the proximal end surface of the heater sleeve 430 to provide a seal between these components that inhibits leakage of aerosol from the heater assembly 410 into surrounding portions of the aerosol generating device 300.

[0130] Used for Figure 2 The same material as the material of the O-ring of the first sealing element 326 and the second sealing element 324 may be used Figure 4 The first sealing element 426 and the second sealing element 424 are O-rings.

[0131] Figure 5 The second sealing element 424 seals Figure 4 An enlarged schematic cross-sectional view of the circular area marked E in FIG. Figure 3 In the example, Figure 5 The tubular heater 416 has an expanded proximal end 416a. The inner surface of the second heater housing 414 and the proximal end surface of the heater sleeve 430 define a recess or groove 428 for receiving the expanded proximal end 416a of the tubular heater 416. The second sealing element 424 is also located in the groove 428 and engages the inner surface of the groove 428 and the outer surface of the tubular heater 416 to inhibit aerosol from leaking from the tubular heater 416 into the air space 423 between the tubular heater 416 and the heater sleeve 430. The second sealing element 424 is placed on the side of the tubular heater 416 opposite to where the airflow path 422 passes through the tubular heater 416 so that the wall of the tubular heater 416 acts as a physical barrier between the second sealing element 424 and the airflow path 422, which keeps the second sealing element 424 separated from the airflow path 422. At the distal end of the tubular heater 416, a second sealing element 424 is also provided in the first heater housing 412. Figure 5 A groove arrangement similar to the groove arrangement shown in .

[0132] Figure 61 is a side view of an exemplary tubular heater 16 for a heater assembly according to the present disclosure. The tubular heater 16 comprises a stainless steel tube having a circular cross-section. The hollow interior space within the tubular heater 16 has an inner diameter substantially corresponding to the outer diameter of the aerosol generating article, so that the tubular heater 16 can receive the aerosol generating article (not shown) within the interior space. The portion 16a of the tubular heater 16 at each end of the tubular heater 16 expands outward to form a funnel shape at each end of the tubular heater 16. The expanded portions 16a each have a length l1, and the percentage of the total length l of the tubular heater 16 constituted by each length l1 of the expanded portion can be in the range of 5% and 15%. The expanded end portions 16a of the tubular heater 16 each form an angle θ with the longitudinal axis of the tubular heater 16. In this example, θ is approximately 45 degrees, but other suitable angles may be used. Due to the expanded end portions 16a, the outer diameter D at both ends of the tubular heater 16 is greater than the outer diameter d of the tubular heater 16 between the two expanded end portions 16a.

[0133] The portion 16b of the tubular heater 16 between the two flared end portions 16a has straight sides parallel to the longitudinal axis of the tubular heater 16. The straight portion 16b of the tubular heater 16 has a length that substantially corresponds to the length of an aerosol-forming substrate disposed in an aerosol-generating article that is configured to be received within the tubular heater 16.

[0134] Figure 7 5 is a cross-sectional view of a heater assembly 510 according to another example of the present disclosure. The heater assembly 510 includes a first heater housing 512, a second heater housing 514, and a tubular heater 516 for heating an aerosol-forming substrate received in the tubular heater 516. The tubular heater 516 is arranged between the first heater housing 512 and the second heater housing 514. Figure 7 The air inlet 518 at the distal end of the first heater housing 512 (indicated by multiple arrows 522 in the figure) extends through the heater assembly 510 to the aerosol outlet 520 at the proximal end of the second heater housing 514, and passes through the first heater housing 512, the tubular heater 516 and the second heater housing 514.

[0135] and Figure 2 and 4 The instances are different. Figure 7 The heater assembly 510 of FIG. 5 does not use an O-ring as a sealing element to seal the first heater housing 512 and the second heater housing 514 to the tubular heater 516. Instead, Figure 7In the example, the first sealing element 526 and the second sealing element 524 include opposing end sections 516c of the tubular heater 516, which are respectively fixed in sealing engagement with the inner surface 512a of the first heater housing 512 and the inner surface 514a of the second heater housing 514.

[0136] The first sealing element 526 and the second sealing element 524 may be formed by securing the end section 516c of the tubular heater 516 in sealing engagement within grooves or channels 512b and 514b that extend circumferentially around the inner surface 512a of the first heater housing 512 and the inner surface 514a of the second heater housing 514, respectively. Alternatively, the first sealing element 524 and the second sealing element 524 may be provided by forming the first heater housing 512 and the second heater housing 514 around the end section 516c of the tubular heater 516, or driving the end section 516c of the tubular heater 516 into the first heater housing 512 and the second heater housing 514, respectively, so that the end section 516c is embedded in the inner surface 512a of the first heater housing 512 and the inner surface 514a of the second heater housing 514, respectively. The sealing engagement of the first sealing element 526 and the second sealing element 524 may be achieved by one or more of the following processes: insert molding, overmolding, heat staking, high frequency welding, and ultrasonic welding. It should be understood that other suitable processes may also be used.

[0137] The end section 516c of the tubular heater 516 is elongated so that it can extend into the grooves or channels 512b and 514b or the inner surfaces 512a and 514a of the first and second heater housings 512 and 514, respectively, while maintaining the same length of the tubular heater 516 between the first and second heater housings 512 and 514. The surface of the end section 516c of the tubular heater 516 is roughened to have a surface finish with an ISO roughness value in the range of N9 to N12 to help retain the end section 516c in the grooves or channels 512b and 514b or to help adhere the material of the first and second heater housings 512 and 514 to the end section 516c.

[0138] exist Figure 7In the exemplary heater assembly 510 of FIG. 5 , the opposing end segments 516 c are sealed within the first heater housing 512 and the second heater housing 514. The sealing engagement of the opposing end segments 516 c of the tubular heater 516 with the grooves or channels 512 b and 514 b or the inner surfaces of the first heater housing 512 and the second heater housing 514 helps seal the airflow path 522 and protect the opposing end segments 516 c. In addition, the materials of the first heater housing 512 and the second heater housing 514 surrounding the end segments 516 c act as a physical barrier between the end segments 516 c and the airflow path.

[0139] Figure 8 For Figure 7 5 is a side view of a tubular heater 516 of the heater assembly 510, showing the tubular heater 516 in greater detail. Figure 8 The shape and size of the tubular heater 516 are similar to Figure 6 The tubular heater 16 is substantially the same except that Figure 8 The tubular heater 516 has an elongated end section 516c. The tubular heater 516 includes a stainless steel tube having a circular cross-section. A portion 516a of the tubular heater 516 near each end of the tubular heater 516 expands outward to form a funnel shape at each end of the tubular heater 516. The expanded end sections 516a of the tubular heater 516 each form an angle ß with the longitudinal axis of the tubular heater 516. In this example, ß is approximately 45 degrees, but other suitable angles may be used. Due to the expanded end sections 516a, the outer diameter D at both ends of the tubular heater 516 is greater than the outer diameter d of the tubular heater 16 between the two expanded end sections 516a. The two end sections 516c of the tubular heater 516 are elongated and extend a distance l2 in a direction parallel to the longitudinal axis of the tubular heater 516. The percentage of the total length l of the tubular heater 516 that is constituted by each length l2 of the end section may be in the range between 5% and 15%. As described above, the surface of the end section 516 c of the tubular heater 516 is roughened to have a surface finish having an ISO roughness value in the range of N9 to N12.

[0140] Fig. 9 is a cross-sectional view of a heater assembly 610 according to another example of the present disclosure. Fig. 9 The heater components 610 are respectively Figure 4 and Figure 7The heater assembly 610 includes a first heater housing 612, a second heater housing 614, and a tubular heater 616 for heating an aerosol-forming substrate received in the tubular heater 616. The tubular heater 616 is arranged between the inner surfaces of the first heater housing 612 and the second heater housing 614. The heater sleeve 630 is arranged between the opposite end surfaces of the first heater housing 612 and the second heater housing 614. The heater sleeve 630 circumferentially surrounds substantially the entire length of the tubular heater 616, except for the two ends of the tubular heater 616 located within the first heater housing 612 and the second heater housing 614. The airflow path (composed of Fig. 9 The air inlet 618 at the distal end of the first heater housing 612 (indicated by multiple arrows 622 in the figure) extends through the heater assembly 610 to the aerosol outlet 620 at the proximal end of the second heater housing 614, and passes through the first heater housing 612, the tubular heater 616 and the second heater housing 614.

[0141] Similar to Figure 7 The heater assembly 510, Fig. 9 The heater assembly 610 has a first sealing element 626 and a second sealing element 624 including opposing end sections 616c of a tubular heater 616, wherein the end sections 616c are respectively fixed in sealing engagement with the inner surface 612a of the first heater housing 612 and the inner surface 614a of the second heater housing 614.

[0142] Fig. 9 The heater assembly 610 also includes a third sealing element 632 and a fourth sealing element 634 to seal the tubular heater 616 to the first heater housing 612 and the heater sleeve 630 and to seal the tubular heater 616 to the second heater housing 614 and the heater sleeve 630, respectively. The third sealing element 632 and the fourth sealing element 634 are connected to the first and second heater housings 612 and 614. Figure 4 The first sealing element 426 and the second sealing element 424 of the heater assembly 410 are identical.

[0143] The third sealing element 632 comprises an O-ring that circumscribes the tubular heater 616 near the distal end of the tubular heater 616. The O-ring contacts the outer surface of the tubular heater 616, the inner surface of the first heater housing 612, and the distal end surface of the heater sleeve 630 to provide a seal between these components that inhibits leakage of aerosol from the heater assembly 610 into surrounding portions of the aerosol generating device (not shown).

[0144] The fourth sealing element 634 comprises an O-ring that circumscribes the tubular heater 616 near the proximal end of the tubular heater 616. The O-ring contacts the outer surface of the tubular heater 616, the inner surface of the second heater housing 614, and the proximal end surface of the heater sleeve 630 to provide a seal between these components that inhibits leakage of aerosol from the heater assembly 610 into surrounding portions of an aerosol generating device (not shown).

[0145] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers indicating amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. In addition, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically listed herein. Therefore, in this context, the number A is understood to be A±5 percent (5%) A. In this context, the number A can be regarded as including values ​​within the general standard error for the measurement of the attribute modified by the number A. In some cases as used in the appended claims, the number A may deviate from the percentages listed above, as long as the amount of A deviation does not significantly affect the basic and novel features of the claimed invention. In addition, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically listed herein.

Claims

1. A heater assembly for an aerosol generating device, the heater assembly comprising: a first heater housing including an air inlet; a second heater housing including an aerosol outlet; a tubular heater for heating the aerosol-forming substrate; an air flow path extending from the air inlet through the heater assembly to the aerosol outlet, the air flow path passing through the first heater housing, the tubular heater, and the second heater housing; a first sealing element configured to seal the first heater housing to the tubular heater; as well as a second sealing element configured to seal the second heater housing to the tubular heater; The first sealing element and the second sealing element are separated from the air flow path.

2. The heater assembly according to claim 1, wherein: The first sealing element comprises an annular seal and is disposed between an inner surface of the first heater housing and an outer surface of the tubular heater.

3. The heater assembly according to claim 1 or 2, wherein: The second sealing element includes an annular seal and is disposed between an inner surface of the second heater housing and an outer surface of the tubular heater.

4. A heater assembly according to any one of the preceding claims, wherein: At least one of the first sealing element and the second sealing element is disposed in a groove or recess formed in an inner surface of a corresponding one of the first heater housing and the second heater housing.

5. A heater assembly according to any one of the preceding claims, wherein: The first heater housing includes a tube holder for holding the tubular heater, the air flow path passing through the tube holder.

6. The heater assembly of claim 5, wherein: The first sealing element is disposed between the tube holder and an outer surface of the tubular heater.

7. The heater assembly of claim 1, wherein: The first and second sealing elements include opposing end sections of the tubular heater secured in sealing engagement to the inner surfaces of the first and second heater housings.

8. The heater assembly of claim 7, wherein: Opposing end sections of the tubular heater are secured in sealing engagement within grooves or recesses formed in the inner surfaces of the first and second heater housings.

9. The heater assembly of claim 7, wherein: Opposing end sections of the tubular heater are embedded in the inner surfaces of the first and second heater housings.

10. The heater assembly of claim 7, wherein: The opposing end sections of the tubular heater have a surface finish having an ISO roughness value in the range of N9 to N12.

11. The heater assembly according to any one of claims 7 to 10, further comprising: a third sealing element configured to further seal the first heater housing to the tubular heater; as well as A fourth sealing element is configured to further seal the second heater housing to the tubular heater.

12. The heater assembly of claim 11, wherein: The third sealing element includes an annular seal and is disposed between an inner surface of the first heater housing and an outer surface of the tubular heater.

13. The heater assembly according to claim 11 or 12, wherein: The fourth sealing element includes an annular seal and is disposed between an inner surface of the second heater housing and an outer surface of the tubular heater.

14. A heater assembly according to any one of the preceding claims, wherein: The tubular heater is enclosed by the first heater housing and the second heater housing.

15. The heater assembly of any one of claims 1 to 13, further comprising a heater sleeve surrounding at least a portion of the tubular heater, the heater sleeve being disposed between the first heater housing and the second heater housing.

16. The heater assembly of claim 15, wherein: The first sealing element engages an inner surface of the first heater housing, an outer surface of the tubular heater, and an inner or end surface of the heater sleeve.

17. A heater assembly according to claim 15 or 16, wherein: The second sealing element engages an inner surface of the second heater housing, an outer surface of the tubular heater, and an inner or end surface of the heater sleeve.

18. A heater assembly according to any one of the preceding claims, wherein: The diameter of the tubular heater at each end of the tubular heater is larger than the diameter of the tubular heater in a region between the two ends of the tubular heater.

19. The heater assembly of claim 18, wherein: A portion of each end of the tubular heater is flared or funnel-shaped.

20. An aerosol generating device comprising: A heater assembly according to any one of the preceding claims; as well as A power supply is provided for supplying power to the heater assembly.

21. An aerosol generating system comprising: The aerosol generating device according to claim 20; as well as An aerosol-generating article comprising an aerosol-forming substrate.

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