Heater assembly with external microporous insulation

Abstract

The heater assembly for an aerosol generating device comprises a heating chamber for heating an aerosol-forming substrate and a heater casing disposed outside the heating chamber. The heating chamber is defined by a heating chamber wall and the heater casing is defined by a heater casing wall. The heater assembly further comprises a microporous insulating material disposed outside the heater casing, for example, substantially surrounding the heater casing. The microporous insulating material allows for effective insulation without the need for a thick layer of material. The microporous insulating material may be formed from separate interlocking parts to facilitate assembly around the heater casing.

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.The present disclosure further relates to an aerosol generating system comprising an aerosol generating device and an aerosol-forming substrate. [Background technology]

[0002] It is known to provide an aerosol-generating device for generating an inhalable vapor. Such a device may heat an aerosol-forming substrate contained in an aerosol-generating article without burning the aerosol-forming substrate. The aerosol-generating article may have a rod shape for inserting the aerosol-generating article into a heating chamber of the aerosol-generating device. A heating element is typically disposed in or around the heating chamber for heating the aerosol-forming substrate after the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device. Summary of the Invention [Problem to be solved by the invention]

[0003] Heat generated by the heating element may inadvertently dissipate from the heating chamber. Heat may dissipate to the environment or to other components of the aerosol generating system. Heat may inadvertently dissipate from the heating chamber by free air convection. Heat may inadvertently dissipate from the heating chamber by radiation. Heat may inadvertently dissipate from the heating chamber by thermal conduction through components of the aerosol generating device. Heat may inadvertently dissipate from the heating chamber by thermal conduction through components of the aerosol generating article, for example, through the aerosol-forming substrate. Heat dissipation from the heating chamber may cause heating of components of the device that are not intended to be heated. For example, the housing of the device that the user grips may become uncomfortably hot. Heat dissipation from the heating chamber may cause heat loss within the heating chamber. Heat loss within the heating chamber may result in less efficient heating. Excessive amounts of energy may be required to heat the heating chamber to the desired temperature.

[0004] It would be desirable to have an aerosol generating device that can reduce heat loss from the heating chamber. It would be desirable to insulate the heating chamber from other components of the aerosol generating device. It would be desirable to have an aerosol generating device that can reduce heating of the outer housing of the device that is gripped by the user. It would be desirable to have an aerosol generating device that can provide effective insulation. It would be desirable to have an aerosol generating device that can provide insulation with low manufacturing costs. It would be desirable to have an aerosol generating device that can provide lightweight insulation. It would be desirable to have an aerosol generating device that can have improved insulation. It would be desirable to have an aerosol generating device that can have a reduced outer diameter of the heater casing. It would be desirable to have an aerosol generating device that can have a more compact device size. [Brief description of the drawings]

[0005] [Figure 1]FIG. 1 is a schematic diagram of one embodiment of a heater assembly for an aerosol generating device. [Diagram 2] FIG. 2 illustrates one embodiment of a heating chamber for a heater assembly, such as the heater assembly of FIG. [Diagram 3] FIG. 2 is a schematic cross-sectional view of the heater assembly of FIG. 1. [Figure 4] FIG. 2 is a schematic cross-sectional view of a second embodiment of a heater assembly for an aerosol generating device. [Diagram 5] FIG. 4 shows the heating assembly of FIG. 3 when installed within the housing of an aerosol generating device. [Figure 6] A schematic cross-sectional view of a third embodiment of a heater assembly for an aerosol generating device. [Figure 7] FIG. 2 is a schematic diagram showing a modular construction of one embodiment of a microporous insulating material for a heater assembly. [Figure 8] FIG. 4 shows an embodiment of an aerosol generating device including the heater assembly shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] According to one embodiment of the present invention, there is provided a heater assembly for an aerosol generating device. The heater assembly includes a heating chamber for heating an aerosol-forming substrate. The heating chamber may be defined by a heating chamber wall. The heater assembly may further include a heater casing disposed external to the heating chamber. The heater casing may be defined by a heater casing wall. The heater assembly may further include a microporous insulating material disposed external to the heater casing.

[0007] Thus, a heater assembly for an aerosol generating device can be provided, the heater assembly comprising: a heating chamber for heating an aerosol-forming substrate, the heating chamber being defined by a heating chamber wall; and a heater casing disposed outside the heating chamber, the heater casing being defined by a heater casing wall; the heater assembly further comprising a microporous insulating material disposed outside the heater casing.

[0008] The heater casing of the aerosol generating device may be insulated by an insulating material such as a polymer. In that case, a suitable material must be selected, and one that does not degrade due to the heat caused by the operation of the device. Insulation may be provided by a gap between the heater casing and any outer housing, and thus by using air as the insulating material. However, at higher temperatures, the thermal conductivity of air increases, and it may be necessary to only widen the gap to perform the desired insulating role. Microporous insulating materials contain small cavities or pores. Air or other gaseous compositions are trapped within these cavities. Thus, microporous insulating materials may have improved thermal barrier properties with increasing temperature, compared to both solid materials and air. Microporous insulating materials may retain or nearly retain their thermal conductivity at the operating temperature of the aerosol generating device, and their low thermal conductivity at room temperature. The low thermal conductivity of the microporous insulating material at the operating temperature of the aerosol generating device provides better insulation. Due to the better insulation, heater assemblies including microporous insulating materials can have a reduced outer diameter.

[0009] The heater assembly may be configured such that the heater casing is disposed external to the outer surface of the heating chamber wall. For example, the heater casing may be disposed around or substantially enclose the heating chamber. In this manner, the heater casing itself acts to some extent as a thermal barrier. The moving air that may otherwise be present around the outer surface of the heater casing may have a thermal conductivity in the range of 0.5 W / mK to at least 25 W / mK. Microporous insulating materials, such as silica aerogel, may have a thermal conductivity of less than 0.017 W / mK. Not only do microporous insulating materials provide significant improvements in thermal insulation, but infrared heat transfer may also be reduced. For example, the use of microporous insulating material external to the heater casing may further reduce infrared heat loss by 10% at typical aerosol generating device operating temperatures, e.g., within the range of 150 degrees Celsius to 350 degrees Celsius.

[0010] By placing the microporous insulation material outside the heater casing, the material is not located in the main airflow of the aerosol generating device. Thus, any risk of contaminating the main airflow with material from the insulation is reduced. Furthermore, the location of the microporous insulation material outside the heater casing means that the maximum temperature experienced by the microporous insulation material is lower than if it were located inside the heater casing. This not only broadens the possible materials that can be used, but also helps maintain the stability of the insulation material over time. The microporous insulation material is preferably at least 0.1 mm thick. Advantages of a heater assembly with a layer of microporous insulation material located outside the heater casing may include the ability to produce an aerosol generating device with reduced dimensions due to the need for a thinner layer of insulation material, the ability to produce an aerosol generating device with a lower external operating temperature, and the ability to save energy by reducing heat loss to the outside world during operation of the device.

[0011] The heating chamber may have an elongated shape, for example defined by an elongated heating chamber wall, preferably the heating chamber wall is in the form of a hollow tube. The heating chamber may be an elongated heating chamber having a substantially polygonal cross-section, for example a substantially polygonal cross-section selected from the list consisting of a circle, an ellipse, a decagon, a nonagon, an octagon, a heptagon, a hexagon, a pentagon, a square, a rectangle, and a triangle. The heating chamber may be a longitudinally extending heating chamber, preferably a longitudinally extending heating chamber defined by a base, a sidewall extending from the base, and an opening at an opposite end of the heating chamber relative to the base.

[0012] The heating chamber is preferably arranged to receive an aerosol-generating article comprising an aerosol-forming substrate, such an aerosol-generating article may be in the form of a rod.

[0013] The heating chamber may be configured to at least partially receive the aerosol-forming substrate. The heating chamber may comprise a cavity into which the aerosol-forming substrate may be inserted. The aerosol-forming substrate may be part of an aerosol-generating article. The cavity may have a shape corresponding to the shape of the aerosol-generating article to be received therein. The cavity may have a circular cross-section.

[0014] The cavity may have an elliptical or rectangular cross section. The cavity may have an inner diameter corresponding to the outer diameter of the aerosol-generating article. The heating chamber may comprise an opening at a proximal end of the heating chamber to receive the aerosol-forming substrate. The opening may also serve as an air outlet. The heating chamber may comprise an air inlet at a distal end of the heating chamber. The heating chamber may have an elongated shape. The heating chamber may be a hollow tube. The hollow tube may be formed from a wall of the heating chamber. The wall of the heating chamber may comprise or be made of a metal or alloy. The wall of the heating chamber may comprise or be made of stainless steel. The heater casing may be disposed radially away from the heating chamber by a distance d. The distance d may be measured in a direction perpendicular to the longitudinal axis of the heating chamber. The heating chamber may comprise a wall of the heating chamber. The heater casing may comprise a wall of the heater casing. The distance d may be measured radially between the wall of the heating chamber and the wall of the heater casing. The distance d may be measured radially between the outside of the wall of the heating chamber and the inside of the wall of the heater casing. The distance d between the heating chamber and the heater casing may be between 1.5 millimeters and 7 millimeters. The distance between the heating chamber and the heater casing may be between 2 millimeters and 4 millimeters, preferably about 3.1 millimeters. The heater casing may be coaxially aligned around the heating chamber. The heating chamber and the heater casing may have matching shapes. The matching shapes may allow for providing a constant radial distance d between the heater casing and the heating chamber. The wall of the heater casing may match the shape of the wall of the heating chamber along the longitudinal axis of the heating chamber such that the distance d may be approximately constant. For example, the heating chamber may be a hollow tube and the wall of the heater casing may be a cylindrical wall that is coaxially aligned around the heating chamber. The distance d may be measured radially between the outer diameter of the hollow tube of the heating chamber and the inner diameter of the cylindrical wall of the heater casing.For example, the heating chamber may be a hollow truncated cone and the heater casing wall may be a conical wall aligned coaxially. Those skilled in the art will appreciate that other types of matching shapes are possible. For example, the matching shapes may be curved or wavy, or may include a combination of different shapes along the longitudinal axis of the heating chamber. The heating chamber and the heater casing may have deviating shapes. The shape of the heater casing wall may deviate to some extent from the shape of the heating chamber wall along the longitudinal axis of the heating chamber. The shape of the heater casing wall may deviate from the shape of the heating chamber wall along the longitudinal axis of the heating chamber such that the distance d does not vary by more than 1 millimeter along the longitudinal axis of the heating chamber. For example, the heating chamber may be a right conical hollow cylinder and the heater casing wall may be a slightly conical hollow cylinder aligned coaxially around the heating chamber. Due to the conical shape of the heater casing wall, the distance d may vary by 1 millimeter or less along the longitudinal axis of the heating chamber.

[0015] The outer diameter of the heater casing may be measured perpendicular to the longitudinal axis of the heating chamber. The outer diameter of the heater casing may be between 8 millimeters and 20 millimeters, preferably between 14 millimeters and 18 millimeters, preferably about 16 millimeters.

[0016] The outer diameter of the heating chamber may be measured in a direction perpendicular to the longitudinal axis of the heating chamber. The ratio of the outer diameter of the heater casing to the outer diameter of the heating chamber may be between 1.3 and 3.5, preferably between 1.5 and 2.5, and more preferably about 2.0. In particular, in one embodiment, the outer diameter of the heating chamber may be about 5.6 millimeters and the outer diameter of the heater casing may be about 17 millimeters, resulting in a ratio of about 3.0. In one embodiment, the outer diameter of the heating chamber may be about 5.6 millimeters and the outer diameter of the heater casing may be about 16.5 millimeters, resulting in a ratio of about 2.95. In one embodiment, the outer diameter of the heating chamber may be about 7.6 millimeters and the outer diameter of the heater casing may be about 16.5 millimeters, resulting in a ratio of about 2.17.

[0017] The heater casing may have an elongated shape, for example defined by an elongated heater casing wall, which may be in the form of a hollow tube.

[0018] The heater casing may define an elongated cavity surrounding at least a portion of the heating chamber. Such an elongated cavity may have a substantially polygonal cross-section, for example a substantially polygonal cross-section selected from the list consisting of a circle, an ellipse, a decagon, a nonagon, an octagon, a heptagon, a hexagon, a pentagon, a square, a rectangle, and a triangle. The heater casing may be a longitudinally extending heater casing, preferably a substantially tubular heater casing. The heater casing is preferably arranged radially away from the heating chamber, for example, in which case the inner surface of the heater casing wall is spaced or radially spaced from the outer surface of the heater chamber wall.

[0019] The heater assembly may be configured such that the microporous insulating material, or at least a portion of the microporous insulating material, is disposed in contact with the exterior surface of the heater casing. Alternatively, the microporous insulating material may be substantially spaced from the exterior surface of the heater casing. For example, the microporous insulating material may be spaced a distance of more than 0.01 mm, such as between about 0.1 mm and 5 mm, such as between 0.5 mm and 4.5 mm, such as between 1 mm and 4 mm, such as between 1.5 mm and 3.5 mm, such as between 2 mm and 3 mm, such as about 2.5 mm.

[0020] In some examples, the microporous insulating material substantially surrounds the heater casing. For example, the microporous insulating material may radially surround the heater casing. The heater casing may have a substantially cylindrical outer surface and the microporous insulating material may radially surround or surround at least a central portion of the heater casing.

[0021] The microporous insulating material may have a thickness of from 0.1 mm to 5 mm, such as from 0.5 mm to 4.5 mm, for example from 1 mm to 4 mm, such as from 1.5 mm to 3.5 mm, for example from 2 mm to 3 mm, such as about 2.5 mm.

[0022] The microporous insulating material preferably has a thermal conductivity of less than 0.05 W / m·K at a temperature of 280 degrees C. For example, the microporous insulating material may have a thermal conductivity of less than 0.04 W / m·K, more preferably less than 0.03 W / m·K, at a temperature of 280 degrees C.

[0023] The thermal conductivity of air increases with increasing temperature. At 25 degrees Celsius the thermal conductivity of air is approximately 0.0262 W / m·K. At an operating temperature of 280 degrees Celsius the thermal conductivity of air is already approximately 0.043 W / m·K. Thus, using air as the only insulating material in, for example, an air gap would require a relatively large thickness to provide sufficient insulation.

[0024] The microporous insulating material may have a lower thermal conductivity than air at room temperature. At high temperatures, the difference between the thermal conductivity of air and the thermal conductivity of the microporous insulating material may be even greater. The thermal conductivity of the microporous insulating material may not increase as quickly as that of air. The microporous insulating material may largely maintain its thermal conductivity as the temperature is increased.

[0025] For example, a microporous insulating material may have a thermal conductivity of 0.018 W / m·K at 20 degrees Celsius. At 200 degrees Celsius, the thermal conductivity of the same microporous insulating material may be 0.022 W / m·K. At a temperature of 400 degrees Celsius, the thermal conductivity of the same microporous insulating material may increase to 0.028 W / m·K according to ASTM C177. The thermal conductivity of this exemplary microporous insulating material is about the same as air at room temperature, even higher than the maximum operating temperature of the aerosol generating device. Lower thermal conductivity provides better insulation. A heater assembly including an insulating material with a lower thermal conductivity may have a smaller thickness of insulation while still providing sufficient insulation.

[0026] The thermal conductivity of the microporous insulating material may be increased by up to 40 percent at a temperature of 280 degrees Celsius compared to the thermal conductivity of the microporous insulating material at room temperature. Preferably, the thermal conductivity of the microporous insulating material may be increased by up to 30 percent, more preferably up to 20 percent, at a temperature of 280 degrees Celsius compared to the thermal conductivity of the microporous insulating material at room temperature.

[0027] The "operating temperature" depends on the type of aerosol-generating device and the aerosol-forming substrate used. The operating temperature of the aerosol-generating device may, for example, be in the range of 150-300 degrees Celsius. The operating temperature of the aerosol-generating device may be in the range of 200-230 degrees Celsius. In some preferred embodiments, the operating temperature of the aerosol-generating device may not exceed 280 degrees Celsius.

[0028] The microporous insulating material may have a pore size of less than 100 nanometers, preferably less than 70 nanometers, more preferably less than 50 nanometers, more preferably less than 20 nanometers, more preferably less than 2 nanometers.

[0029] The microporous insulating material may be a ceramic material, such as a silica-based or alumina-based material. The microporous insulating material may be selected from the list consisting of, for example, MICROSIL microporous insulation from ZIRCAR Ceramics, Inc., Excelfrax® from Unifrax LLC, and Microtherm 1000 grades from Promat Inc.

[0030] The microporous insulating material may be inorganic. The microporous insulating material may be ceramic. The microporous insulating material may include silica (SiO2). The microporous insulating material may include pyrogenic silica. The microporous insulating material may include opacifiers and other components such as fibers. The opacifiers may scatter infrared radiation, thereby reducing the transmission of infrared radiation.

[0031] The microporous insulating material of the present disclosure has a porosity of 500 kg / m 3 Less than 400 kg / m 3 less than 300 kg / m 3 It may have a nominal density of less than 100 nm.

[0032] The microporous insulating material of the present invention may have a thermal conductivity of less than 0.05 W / m·K, preferably less than 0.04 W / m·K, more preferably less than 0.03 W / m·K, more preferably less than 0.02 W / m·K, according to ASTM C177 at 20 degrees Celsius. The microporous insulating material may have a thermal conductivity of less than 0.05 W / m·K, preferably less than 0.04 W / m·K, more preferably less than 0.03 W / m·K, according to ASTM C177 at a temperature of 280 degrees Celsius. The thermal conductivity of the microporous insulating material may be increased by up to 40 percent, preferably up to 30 percent, more preferably up to 20 percent, at a temperature of 280 degrees Celsius compared to the thermal conductivity of the microporous insulating material at 20 degrees Celsius.

[0033] The microporous insulating material can be formed from at least a first insulating element including at least one first connecting element, and a second insulating element including at least one second connecting element, where the first connecting element and the second connecting element are configured as matching connecting elements.

[0034] The first and second connecting elements may be configured as male and female connecting elements, as form-fit connecting elements, as snap-fit ​​connecting elements, as bayonet connecting elements or combinations thereof, or other commonly used connecting elements known to those skilled in the art. The first connecting element may include a male connecting element and the second connecting element may include a female connecting element. The first and second connecting elements may include form-fit connecting elements. The first and second connecting elements may include snap-fit ​​connecting elements. The first and second connecting elements may include bayonet connecting elements. The microporous insulating material may be configured as a two-part assembly. The two-part assembly may include a first insulating element and a second insulating element. The first and second insulating elements may be in the form of, for example, hollow semi-cylindrical elements. The hollow semi-cylindrical elements may include mating first and second connecting elements. When connected, the hollow semi-cylindrical elements may form a single hollow tube. The inner diameter of the hollow tube may have the same size as the outer diameter of the heating chamber. This can ensure easy assembly. On the other hand, a microporous insulating material formed as one piece with an inner diameter the same as the outer diameter of the heating chamber may be more difficult to assemble around the heating chamber due to friction. The close or direct contact of the microporous insulating material with the heating chamber can improve the insulation of the heating chamber.

[0035] The heater assembly according to the present disclosure further comprises a first connecting wall connecting the heating chamber and the heater casing, and a second connecting wall connecting the heating chamber and the heater casing, where a space is defined between the heating chamber, the heater casing, and the first and second connecting walls, for example, an airtight space is defined between the heating chamber, the heater casing, and the first and second connecting walls. Such connecting walls may be oriented perpendicular to the longitudinal axis of the heating chamber.

[0036] The airtight space may provide additional insulation. Such airtight space may be at ambient pressure or may be at least partially filled with a gaseous composition at ambient pressure.

[0037] The microporous insulating material of the heater assembly may be described as a first portion of microporous insulating material, and the heater assembly may further include a second portion of microporous insulating material disposed between the interior surface of the heater casing and the exterior surface of the heating chamber. The second portion of microporous material may be a different microporous material than the first portion of microporous material, or the same microporous material as the first portion of microporous material. The second microporous material may be a material having the properties described above for the microporous insulating material.

[0038] The heater casing may include or define an airtight space. For example, the airtight space may be defined between an interior surface of the heater casing wall and an exterior surface of the heating chamber wall. Such an airtight space may include a second portion of microporous insulating material. Such an airtight space may include at least one void. In some examples, the second portion of microporous insulating material may be sandwiched between two radially spaced voids.

[0039] If present, the second portion of the microporous insulating material may be in direct contact with the heating chamber, e.g., in direct contact with the exterior surface of the heating chamber. The second portion of the microporous insulating material may be in direct contact with a heating element disposed on or about the exterior surface of the heating chamber. The second portion of the microporous insulating material may be in direct contact with a heater casing, e.g., in direct contact with an interior surface of the heater casing.

[0040] If present, the second portion of the microporous insulating material may be formed from at least a first insulating element including at least one first connecting element, and a second insulating element including at least one second connecting element, the first connecting element and the second connecting element being configured as mating connecting elements. The first connecting element may include a male connecting element, and the second connecting element may include a female connecting element. The first connecting element and the second connecting element may include any suitable connecting system, for example, they may include form-fit connecting elements, or may include snap-fit ​​connecting elements, or may include bayonet connecting elements.

[0041] In some preferred embodiments, the microporous insulating material and / or the second portion of the microporous insulating material may extend parallel to a longitudinal axis of the heating chamber, for example, the heating chamber may be tubular and the microporous insulating material may be tubular, or substantially tubular, or may be coated on a surface of a tube surrounding the heating chamber.

[0042] The distance between the heating chamber and the heater casing, for example the spacing between the outer surface of the heating chamber and the inner surface of the heater casing, may be between 1.5 millimeters and 7 millimeters, preferably between 2 millimeters and 4 millimeters, preferably about 3.1 millimeters.

[0043] The heater assemblies described herein may further include a heating element. The heating element may be disposed at least partially about the heating chamber. The microporous insulating material may have a longitudinal extension that is the same as or greater than the longitudinal extension of the heating element.

[0044] The heating element may be flexible and may be wrapped around the heating chamber. The heating element may be disposed between the heating chamber and the heater casing. The heating element may comprise one or more conductive tracks on an electrically insulated substrate, for example a polyimide substrate.

[0045] The ratio of the outer diameter of the heater casing to the outer diameter of the heating chamber may be 1.3 to 3.5, preferably 1.5 to 2.5, more preferably about 2.0. The inside of the heater casing wall may be provided with a metal coating, which may facilitate reflection of heat towards the chamber and / or distribute heat evenly over the inner surface of the heater casing, thereby reducing the effect of hot spots. The heating chamber wall may comprise stainless steel.

[0046] The heater casing wall or walls preferably have a thickness of less than 2 millimeters, preferably less than 1.2 millimeters, preferably about 0.8 millimeters. The heater casing may comprise a plastic material. For example, the heater casing wall or walls may comprise a plastic material, preferably polyaryletherketone (PAEK), polyetheretherketone (PEEK), or polyphenylenesulfone (PPSU), more preferably polyphenylenesulfone (PPSU).

[0047] In one aspect, an aerosol generating device may be provided, the aerosol generating device comprising a heater assembly according to any embodiment described herein. The heater assembly for such a device may be of narrow dimensions, and thus an aerosol generating device comprising such a heater assembly may have more compact dimensions than would otherwise be expected. Such an aerosol generating device preferably comprises a housing, a power source, control electronics, and a heater assembly.

[0048] The aerosol generating device preferably comprises a power source configured to provide power to the heating element. The power source preferably comprises a power source. The power source is preferably a battery, such as a lithium ion battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for about six minutes, or a multiple of six minutes. In another example, the power source may have a capacity sufficient to allow a predetermined number of puffs, or discontinuous activation of the heater assembly. The power source may comprise control electronics. The control electronics may comprise a microcontroller. The microcontroller is preferably a programmable microcontroller. The electrical circuit may include further electronic components. The electrical circuit may be configured to regulate the supply of power to the heater assembly. Power may be supplied to the heater assembly continuously after activation of the system, or intermittently (e.g., between puffs). Power may be supplied to the heater assembly in the form of current pulses.

[0049] In an aerosol generating device, the heater assembly may be located by or within a housing of the aerosol generating device. The microporous insulating material of the heater assembly may be located between an outer surface of the heater casing and an inner surface of the housing. In some embodiments, the microporous insulating material may be spaced apart from the inner surface of the housing. In some embodiments, the microporous insulating material may be spaced apart from both the inner surface of the housing and the outer surface of the heater casing. In still further embodiments, the microporous insulating material may substantially fill a space defined between the outer surface of the heater casing and the inner surface of the housing.

[0050] The heating chamber may be defined by a substantially cylindrical heating chamber wall. For example, the heater casing may be defined by a substantially cylindrical heater casing wall located radially outside the heating chamber, the microporous insulating material may be located radially outside the heater casing wall, and the housing may be located radially outside the microporous insulating material. The heater may be located on at least a portion of an exterior surface of the heating chamber wall. In some embodiments, a sealed gap may be defined between the heating chamber and the heater casing.

[0051] The aerosol generating device preferably includes a heater and preferably includes control electronics located within a housing controlling operation of the heater.

[0052] In a preferred embodiment, an airflow path may be defined through the heating chamber, the airflow path preferably not being in contact with the microporous insulating material.

[0053] In a further aspect, there may be provided an aerosol generation system comprising an aerosol generating device as described herein and an aerosol-forming substrate configured to be at least partially received in a heated chamber. The aerosol-forming substrate may be a component of an aerosol-generating article, for example an elongated aerosol-generating article, the aerosol-generating article comprising the aerosol-forming substrate. The aerosol-generating article may comprise a mouthpiece located upstream of the aerosol-forming substrate.

[0054] The aerosol-generating article may be a rod-shaped, e.g. substantially cylindrical, aerosol-generating article having a diameter of 4 mm to 8 mm, e.g. 4.5 mm to 7.5 mm, e.g. 5 mm to 7.2 mm. The aerosol-generating device may comprise an opening configured to allow a portion of the aerosol-generating device to be inserted into the heating chamber. For example, the heating chamber may have an inner diameter approximately the same as the diameter of the aerosol-generating article.

[0055] As used herein, the terms "upstream" and "downstream" are used to describe the relative location of a component or portion of a component of a heater assembly, aerosol-generating device, or aerosol-generating article with respect to the direction in which air flows through the assembly, device, or article during use.

[0056] An aerosol generating device according to the invention may comprise a proximal end through which the aerosol exits the device in use. The proximal end of the aerosol generating device may also be referred to as the oral end or downstream end. The oral end is downstream of the distal end. The distal end of the aerosol generating device may also be referred to as the upstream end. Components or parts of components of an aerosol generating device may be described as being upstream or downstream of each other based on their relative location with respect to the airflow path of the aerosol generating device.

[0057] An aerosol-generating article according to the invention may comprise a proximal end through which aerosol exits the article in use. The proximal end of the aerosol-generating article may also be referred to as the oral end or downstream end. The oral end is downstream of the distal end. The distal end of the aerosol-generating article may also be referred to as the upstream end. Components or portions of components of an aerosol-generating article may be described as being upstream or downstream of each other based on their relative location with respect to the airflow path of the aerosol-generating article.

[0058] The proximal end of a heater assembly according to the invention may be configured to be positioned within an aerosol generating device in a direction towards the mouth or downstream end of the device. The distal end of a heater assembly according to the invention may be configured to be positioned within an aerosol generating device in a direction towards the distal or upstream end of the device. The longitudinal axis of the heating chamber may extend between the proximal end of the heating chamber and the distal end of the heating chamber. The longitudinal axis of the heating chamber may extend between the proximal end of the heater assembly and the distal end of the heater assembly.

[0059] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate capable of releasing a volatile compound capable of forming an aerosol. The aerosol-generating article may be disposable.

[0060] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing a volatile compound capable of forming an aerosol. The volatile compound may be released by heating or burning the aerosol-forming substrate. As an alternative to heating or burning, in some cases the volatile compound may be released by a chemical reaction or by mechanical stimulation such as ultrasound. The aerosol-forming substrate may be solid or liquid, or may include both solid and liquid components. The aerosol-forming substrate may be part of an aerosol-generating article.

[0061] The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosol-forming substrate may include both solid and liquid components. The aerosol-forming substrate may include a tobacco-containing material that contains volatile tobacco flavor compounds that are released from the substrate upon heating. The aerosol-forming substrate may include a non-tobacco material. The aerosol-forming substrate may include an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0062] As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-generating device may interact with one or both of an aerosol-generating article that includes an aerosol-forming substrate and a cartridge that includes an aerosol-forming substrate. In some examples, the aerosol-generating device may heat the aerosol-forming substrate to facilitate the release of volatile compounds from the substrate. An electrically operated aerosol-generating device may include an atomizer, such as an electric heater, for heating the aerosol-forming substrate to form an aerosol.

[0063] The term "aerosol-generating system" as used herein refers to the combination of an aerosol-generating device with an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol-generating system refers to the combination of an aerosol-generating device with the aerosol-generating article. In an aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device work together to generate an aerosol.

[0064] In any aspect described herein, the heating chamber may comprise a temperature sensor. The temperature sensor may be on a top of the heating chamber. The heater assembly may further comprise a heating element. The heating chamber may include a heating element. The heating element may be disposed at least partially around the heating chamber. The heating element may be disposed at least partially around the wall of the heating chamber. The heating element is preferably disposed completely coaxially around the outer periphery of the wall of the heating chamber. The heating element may be disposed along at least a portion of the longitudinal axis of the heating chamber. The heating element may comprise one or more conductive tracks on an electrically insulated substrate. The one or more conductive tracks may be resistive heating tracks. The one or more conductive tracks may be configured as an inductively heated susceptor. The electrically insulated substrate may be a flexible substrate.

[0065] The heating element may be flexible and may be wrapped around the heating chamber. The heating element may be disposed between the heating chamber and the heater casing. In all aspects of the present disclosure, the heating element may comprise an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, alloys, and composites made of ceramic and metallic materials. Such composites may comprise doped or undoped ceramics.

[0066] As described, in any of the aspects of the present disclosure, the heating element may be part of the heating chamber of the heater assembly for the aerosol generating device. The heater assembly may comprise an internal heating element, or an external heating element, or both an internal heating element and an external heating element, where "internal" and "external" refer to the aerosol-forming substrate. The internal heating element may take any suitable form. For example, the internal heating element may take the form of a heating blade. Alternatively, the internal heater may take the form of a casing or substrate having different conductive portions or electrically resistive metal tubes. Alternatively, the internal heating element may be one or more heating needles or rods that pass through the center of the aerosol-forming substrate. Other alternatives include heating wires or filaments, such as Ni-Cr (nickel chromium), platinum, tungsten, or alloy wires or heating plates. Optionally, the internal heating element may be disposed in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may 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 on a suitable insulating material, such as a ceramic material, and then sandwiched in another insulating material, such as glass. The heater thus formed may be used to both heat the heating element and monitor its temperature during operation.

[0067] The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils on a dielectric substrate such as polyimide. The flexible heating foils may be shaped to fit the periphery of the substrate receiving cavity. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a molded integrated circuit device (MID), a ceramic heater, a flexible carbon fiber heater, or may be formed using a coating technique such as plasma deposition on a substrate of suitable shape. The external heating element 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. An external heating element formed in this manner may be used both to heat the external heating element and to monitor the temperature of the external heating element during operation.

[0068] The heating element advantageously heats the aerosol-forming substrate by thermal conduction. The heating element may be in at least partial contact with the substrate or at least partial contact with the carrier on which the substrate is deposited. Alternatively, heat from either an internal or external heating element may be conducted to the substrate by a thermally conductive element.

[0069] In operation, the aerosol-forming substrate may be completely contained within the aerosol-generating device, in which case a user may puff on the mouthpiece of the aerosol-generating device. Alternatively, in operation, a smoking article containing the aerosol-forming substrate may be partially contained within the aerosol-generating device, in which case a user may puff on the smoking article directly.

[0070] The heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. Generally, a susceptor is a material that has the ability to generate heat when penetrated by an alternating magnetic field.

[0071] According to the present invention, the susceptor may be conductive, or magnetic, or both conductive and magnetic. An alternating magnetic field generated by one or several induction coils heats the susceptor, which then transfers heat to the aerosol-forming substrate, thereby forming the aerosol. The heat transfer may be mainly by conduction of heat. Such heat transfer is best when the susceptor is in intimate thermal contact with the aerosol-forming substrate. When an induction heating element is employed, the induction heating element may be configured as an internal heating element as described herein, or as an external heater as described herein. When the induction heating element is configured as an internal heating element, the susceptor element is preferably configured as a pin or blade for penetrating the aerosol-generating article. When the induction heating element is configured as an external heating element, the susceptor element is preferably configured as a cylindrical susceptor that at least partially surrounds or forms the sidewall of a cavity.

[0072] The heating chamber may comprise a central region comprising the heating element. The term central region refers to the longitudinal direction. The heating chamber may further comprise a proximal region and a distal region. The proximal region and the distal region may be longitudinally spaced away from the heating element. In use, the proximal region and the distal region may be cooler than the central region of the heating chamber. The first connecting wall may contact the heating chamber in the proximal region and the second connecting wall may contact the heating chamber in the distal region. Thus, the first connecting wall and the second connecting wall may contact the heating chamber at the coldest point of the heating chamber in use. Thereby, heat loss from the heating chamber to the connecting walls and the heater casing may be further reduced. Thermal insulation may be further improved.

[0073] The walls of the heating chamber may be made of stainless steel. This may advantageously enhance the effect that the proximal and distal regions may be cooler than the central region of the heating chamber during use. The heater casing wall may have a thickness of less than about 2 millimeters. The heater casing wall may have a thickness of less than 1.2 millimeters, preferably about 0.8 millimeters. One or both of the first and second connecting walls may have a thickness of less than 1.2 millimeters, preferably about 0.8 millimeters. Having such thin walls may minimize the thermal mass of the heater casing. This may further reduce heat loss from the heating chamber.

[0074] One or more of the heater casing wall and the first and second connecting walls may be made of a low thermal conductivity material. This may further reduce heat loss from the heating chamber. The heater casing wall may include or be made of a plastic material. The first and second connecting walls may include or be made of a plastic material. The plastic material may include one or both of polyaryletherketone (PAEK), polyetheretherketone (PEEK), polyphenylenesulfone (PPSU). The plastic material preferably includes polyphenylenesulfone (PPSU). The inside of the heater casing wall may include a metal coating. The inside of one or both of the first and second connecting walls may include a metal coating. The metal coating may reduce the emissivity of the inside of the wall. For example, the emissivity of a PEEK wall may be reduced from about 0.95 to about 0.4. The metal coating may reflect thermal radiation radiated from the heating chamber. The metal coating may provide additional insulation of the heating chamber against the exterior of the heater casing. The metal coating may be a low emissivity metal coating. The metal coating may include one or more of aluminum, gold, and silver.

[0075] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0076] Example 1: A heater assembly for an aerosol generating device comprising: a heating chamber for heating the aerosol-forming substrate, the heating chamber being defined by a heating chamber wall; a heater casing disposed outside the heating chamber, the heater casing being defined by a heater casing wall; The heater assembly further comprises a microporous insulating material disposed on an exterior of the heater casing.

[0077] Example 2: A heater assembly according to Example 1, wherein the heater casing is disposed external to the outer surface of the heating chamber wall.

[0078] Example 3: A heater assembly according to any of the preceding examples, wherein the heater casing is disposed around the heating chamber, e.g., the heater casing substantially surrounds the heating chamber.

[0079] Example 4: A heater assembly according to any of the preceding examples, wherein the heating chamber has an elongated shape, e.g., an elongated shape defined by elongated heating chamber walls, preferably the heating chamber is in the form of a hollow tube.

[0080] Example 5: A heater assembly according to any of the preceding examples, wherein the heating chamber is an elongated heating chamber having a substantially polygonal cross-section, for example, a substantially polygonal shape selected from the list consisting of a circle, an ellipse, a decagon, a nonagon, an octagon, a heptagon, a hexagon, a pentagon, a square, a rectangle, and a triangle.

[0081] Example 6: An aerosol generating device according to any of the preceding examples, wherein the heating chamber is arranged to receive an aerosol-generating article comprising an aerosol-forming substrate.

[0082] Example 7: A heater assembly according to any of the preceding examples, wherein the heating chamber is a longitudinally extending heating chamber, preferably a longitudinally extending heating chamber defined by a base, a sidewall extending from the base, and an opening at an opposite end of the heating chamber relative to the base.

[0083] Example 8: A heater assembly according to any of the preceding examples, wherein the heater casing has an elongated shape, e.g., an elongated shape defined by an elongated heater casing wall, preferably the heater casing wall is in the form of a hollow tube.

[0084] Example 9: A heater assembly according to any of the preceding examples, wherein the heater casing defines an elongated cavity surrounding at least a portion of the heating chamber, the elongated cavity preferably being an elongated cavity having a substantially polygonal cross-section, for example, a substantially polygonal shape selected from the list consisting of a circle, an ellipse, a decagon, a nonagon, an octagon, a heptagon, a hexagon, a pentagon, a square, a rectangle, and a triangle.

[0085] Example 10: A heater assembly according to any of the preceding examples, wherein the heater casing is a longitudinally extending heater casing, preferably a substantially tubular heater casing.

[0086] Example 11: A heater assembly according to any of the preceding examples, wherein the heater casing is positioned radially away from the heating chamber, e.g., an inner surface of the heater casing wall is spaced apart or radially spaced apart from an outer surface of the heating chamber wall.

[0087] Example 12: A heater assembly according to any of the preceding examples, wherein the heater casing includes or defines an airtight space.

[0088] Example 13: The heater assembly according to example 12, wherein the airtight space is defined between an inner surface of the heater casing wall and an outer surface of the heating chamber wall.

[0089] Example 14: A heater assembly according to any of the preceding examples, wherein the microporous insulating material is disposed in direct contact with an exterior surface of the heater casing.

[0090] Example 15: A heater assembly according to any of Examples 1 to 13, wherein the microporous insulating material is substantially spaced from the exterior surface of the heater casing, for example by a distance of more than 0.01 mm, for example by a distance of about 0.1 mm to 5 mm, for example by 0.5 mm to 4.5 mm, for example by a distance of 1 mm to 4 mm, for example by a distance of 1.5 mm to 3.5 mm, for example by a distance of 2 mm to 3 mm, for example by a distance of about 2.5 mm.

[0091] Example 16: A heater assembly according to any of the preceding examples, wherein the microporous insulating material substantially surrounds the heater casing.

[0092] Example 16A: A heater assembly according to any of the preceding examples, wherein the microporous insulating material radially surrounds the heater casing, e.g., the heater casing has a substantially cylindrical outer surface and the microporous insulating material radially surrounds or encircles at least a central portion of the heater casing.

[0093] Example 17: A heater assembly according to any of the preceding examples, wherein the microporous insulating material has a thickness of from 0.1 mm to 5 mm, such as from 0.5 mm to 4.5 mm, for example from 1 mm to 4 mm, such as from 1.5 mm to 3.5 mm, for example from 2 mm to 3 mm, such as about 2.5 mm.

[0094] Example 18: A heater assembly according to any of the preceding examples, wherein the microporous insulating material has a thermal conductivity of less than 0.05 W / m·K, preferably less than 0.04 W / m·K, and more preferably less than 0.03 W / m·K at a temperature of 280 degrees Celsius.

[0095] Example 19: A heater assembly according to any of the preceding examples, wherein the thermal conductivity of the microporous insulating material is increased by up to 40 percent, preferably up to 30 percent, and more preferably up to 20 percent at a temperature of 280 degrees Celsius compared to the thermal conductivity of the microporous insulating material at room temperature.

[0096] Example 20: A heater assembly according to any of the preceding examples, wherein the microporous insulating material has a pore size of less than 100 nanometers, preferably less than 70 nanometers, more preferably less than 50 nanometers, more preferably less than 20 nanometers, more preferably less than 2 nanometers.

[0097] Example 21: A heater assembly according to any of the preceding examples, wherein the microporous insulating material is a ceramic material, such as a silica-based or alumina-based material, e.g., the microporous insulating material is selected from the list consisting of MICROSIL microporous insulation manufactured by ZIRCAR Ceramics, Inc., Excelfrax® manufactured by Unifrax LLC, and Microtherm 1000 grade manufactured by Promat Inc.

[0098] Example 22: A heater assembly according to any of the preceding examples, wherein the microporous insulation material is formed from at least a first insulation element including at least one first connecting element, and a second insulation element including at least one second connecting element, and the first connecting element and the second connecting element are configured as mating connecting elements.

[0099] Example 23: The heater assembly according to example 22, wherein the first connecting element comprises a male connecting element and the second connecting element comprises a female connecting element.

[0100] Example 24: The heater assembly according to example 22 or example 23, wherein the first connecting element and the second connecting element comprise form-fit connecting elements.

[0101] Example 25: A heater assembly according to any of Examples 22 to 24, wherein the first connecting element and the second connecting element comprise snap-fit ​​connecting elements.

[0102] Example 26: The heater assembly according to any of Examples 22 to 24, wherein the first connecting element and the second connecting element comprise bayonet connecting elements.

[0103] Example 27: First connecting the heating chamber and the heater casing The heater assembly according to any of the preceding embodiments, further comprising a connecting wall and a second connecting wall connecting the heating chamber and the heater casing, e.g., an airtight space is defined between the heating chamber, the heater casing, and the first and second connecting walls.

[0104] Example 28: A heater assembly according to Example 27, wherein the connecting wall is oriented perpendicular to the longitudinal axis of the heating chamber.

[0105] Example 29: A heater assembly according to example 12, or any example dependent on example 12, wherein the hermetic space is at ambient pressure or the hermetic space is at least partially filled with the gaseous composition at ambient pressure.

[0106] Example 30: A heater assembly according to any of the preceding examples, wherein the microporous insulating material is a first portion of microporous insulating material, and the heater assembly includes a second portion of microporous insulating material disposed between an interior surface of the heater casing and an exterior surface of the heating chamber.

[0107] Example 31: A heater assembly according to Example 30, wherein the heater casing comprises or defines an airtight space, e.g., the airtight space is defined between an inner surface of the heater casing wall and an outer surface of the heating chamber wall, and the airtight space contains a second portion of microporous insulating material.

[0108] Example 32: The heater assembly according to Example 30 or Example 31, wherein the second portion of microporous material is a different microporous material than the first portion of microporous material.

[0109] Example 33: A heater assembly according to any of Examples 30 to 32, wherein the second portion of the microporous insulating material has a thickness of 0.1 mm to 5 mm, such as 0.5 mm to 4.5 mm, for example 1 mm to 4 mm, such as 1.5 mm to 3.5 mm, for example 2 mm to 3 mm, such as about 2.5 mm.

[0110] Example 34: A heater assembly according to any of Examples 30 to 33, wherein the second portion of the microporous insulating material has a thermal conductivity of less than 0.05 W / m·K, preferably less than 0.04 W / m·K, and more preferably less than 0.03 W / m·K at a temperature of 280 degrees Celsius.

[0111] Example 35: A heater assembly according to any of Examples 30 to 33, wherein the conductivity of the second portion of the microporous insulating material is increased by up to 40 percent, preferably up to 30 percent, and more preferably up to 20 percent at a temperature of 280 degrees Celsius compared to the thermal conductivity of the microporous insulating material at room temperature.

[0112] Example 36: A heater assembly according to any of Examples 30 to 35, wherein the second portion of the microporous insulating material has a pore size of less than 100 nanometers, preferably less than 70 nanometers, more preferably less than 50 nanometers, more preferably less than 20 nanometers, more preferably less than 2 nanometers.

[0113] Example 37: A heater assembly according to any of Examples 30 to 36, wherein the second portion of the microporous insulating material is a ceramic material, such as a silica-based or alumina-based material, e.g., the second portion of the microporous insulating material is selected from the list consisting of MICROSIL microporous insulation manufactured by ZIRCAR Ceramics, Inc., Excelfrax® manufactured by Unifrax LLC, and Microtherm 1000 grade manufactured by Promat Inc.

[0114] Example 38: A heater assembly according to any of Examples 31 to 37, wherein the airtight space includes at least one void.

[0115] Example 39: A heater assembly according to any of Examples 31-38, wherein the second portion of the microporous insulating material is radially sandwiched between two voids.

[0116] Example 40: A heater assembly according to any of Examples 31-39, wherein the second portion of the microporous insulating material is in direct contact with the heating chamber, e.g., in direct contact with an exterior surface of the heating chamber.

[0117] Example 41: A heater assembly according to any of Examples 31-39, wherein the second portion of the microporous insulating material is in contact with a heating element disposed on or about the exterior surface of the heating chamber.

[0118] Example 42: A heater assembly according to any of Examples 31-41, wherein the second portion of the microporous insulating material is in direct contact with the heater casing, e.g., in direct contact with an interior surface of the heater casing.

[0119] Example 43: A heater assembly according to any of Examples 31 to 40, wherein the second portion of the microporous insulating material is formed at least from a first insulating element including at least one first connecting element, and a second insulating element including at least one second connecting element, and the first connecting element and the second connecting element are configured as matching connecting elements.

[0120] Example 44: The heater assembly according to example 43, wherein the first connecting element comprises a male connecting element and the second connecting element comprises a female connecting element.

[0121] Example 45: The heater assembly according to example 43 or example 44, wherein the first connecting element and the second connecting element comprise form-fit connecting elements.

[0122] Example 46: The heater assembly according to any of Examples 43 to 45, wherein the first connecting element and the second connecting element comprise snap-fit ​​connecting elements. Example 47: The heater assembly according to any of Examples 43 to 46, wherein the first connecting element and the second connecting element comprise bayonet connecting elements.

[0123] Example 48: A heater assembly according to any of the preceding examples, wherein the microporous insulating material and the second portion of elongated microporous material extend parallel to the longitudinal axis of the heating chamber.

[0124] Example 49: The heater assembly according to any of the preceding examples, wherein the distance between the heating chamber and the heater casing is between 1.5 mm and 7 mm, preferably between 2 mm and 4 mm, preferably about 3.1 mm. Example 50: The heater assembly according to any of the preceding examples, further comprising a heating element.

[0125] Example 51: The heater assembly according to example 50, wherein the heating element is disposed at least partially around the heating chamber.

[0126] Example 52: A heater assembly according to Example 50 or Example 51, wherein the microporous insulating material has a longitudinal extension that is the same as or greater than the longitudinal extension of the heating element.

[0127] Example 53: A heater assembly according to Example 50-Example 52, wherein the heating element is flexible and wrapped around the heating chamber.

[0128] Example 54: A heater assembly according to any of Examples 50 to 53, wherein the heating element is disposed between the heating chamber and the heater casing.

[0129] Example 55: A heater assembly according to any of Examples 50 to 54, wherein the heating element comprises one or more conductive tracks on an electrically insulated substrate.

[0130] Example 56: A heater assembly according to any of the preceding examples, wherein the ratio of the outer diameter of the heater casing to the outer diameter of the heating chamber is between 1.3 and 3.5, preferably between 1.5 and 2.5, and more preferably about 2.0.

[0131] Example 57: A heater assembly according to any of the preceding examples, wherein the inside of the heater casing wall is provided with a metal coating.

[0132] Example 58: The heater assembly according to any of the preceding examples, wherein the wall of the heating chamber comprises stainless steel.

[0133] Example 59: A heater assembly according to any of the preceding examples, wherein the thickness of the one or more heater casing walls is less than 2 millimeters, preferably less than 1.2 millimeters, preferably about 0.8 millimeters.

[0134] Example 60: A heater assembly according to any of the preceding examples, wherein the one or more heater casing walls comprise a plastic material, preferably polyaryletherketone (PAEK), polyetheretherketone (PEEK), or polyphenylenesulfone (PPSU), more preferably polyphenylenesulfone (PPSU).

[0135] Example 61: A heater assembly according to any of the preceding examples. An aerosol generating device comprising:

[0136] Example 62: An aerosol generating device according to Example 61, comprising a housing, a power source, control electronics, and a heater assembly according to any of Examples 1 to 61.

[0137] Example 63: An aerosol generating device according to Example 61 or Example 62, wherein the heater assembly is positioned by or within a housing of the aerosol generating device and the microporous insulating material is positioned between the outer surface of the heater casing and the inner surface of the housing.

[0138] Example 64: An aerosol generating device according to Example 63, wherein the microporous insulating material is spaced from the inner surface of the housing.

[0139] Example 65: An aerosol generating device according to Example 63 or Example 64, wherein the microporous insulating material is spaced from both the inner surface of the housing and from the outer surface of the heater casing.

[0140] Example 66: An aerosol generating device according to Example 63, wherein the microporous insulating material substantially fills the space defined between the outer surface of the heater casing and the inner surface of the housing.

[0141] Example 67: An aerosol generating device according to any of Examples 61 to 66, wherein the heating chamber is defined by a substantially cylindrical heating chamber wall, the heater casing is defined by a substantially cylindrical heater casing wall located radially outside the heating chamber, the microporous insulating material is located radially outside the heater casing wall, and the housing is located radially outside the microporous insulating material.

[0142] Example 68: An aerosol generating device according to Example 67, wherein the heater is located on at least a portion of the exterior surface of the heating chamber wall.

[0143] Example 69: An aerosol generating device according to Example 67 or Example 68, wherein the sealed gap is defined between the heating chamber and the heater casing.

[0144] Example 70: An aerosol generating device according to any of Examples 67 to 69, wherein the aerosol generating device is provided with a heater, and control electronics located within the housing control the operation of the heater.

[0145] Example 71: An aerosol generating device according to any of Examples 61 to 70, wherein the airflow path is defined through a heated chamber.

[0146] Example 72: An aerosol generating device according to Example 71, wherein the airflow path does not contact the microporous insulating material.

[0147] Example 73: An aerosol generating system comprising an aerosol generating device according to any of Examples 61 to 72 and an aerosol-forming substrate configured to be at least partially received in a heated chamber.

[0148] Example 74: An aerosol-generating system according to Example 73, wherein the aerosol-forming substrate is a component of an elongated aerosol-generating article, the aerosol-generating article comprising the aerosol-forming substrate and a mouthpiece located upstream of the aerosol-forming substrate.

[0149] Example 75: An aerosol generating system according to Example 74, wherein the aerosol generating article is a substantially cylindrical aerosol generating article having a diameter of 4 mm to 8 mm, for example 4.5 mm to 7.5 mm, for example 5 mm to 7.2 mm, and the aerosol generating device has an opening configured to allow a portion of the aerosol generating device to be inserted into the heating chamber.

[0150] Example 76: An aerosol generating system according to Example 75, wherein the heating chamber has an inner diameter approximately the same as the diameter of the aerosol-generating article.

[0151] Features described with respect to one embodiment may be equally applied to other embodiments of the invention.

[0152] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0153] FIG. 1 shows a schematic representation of one embodiment of a heater assembly 10. The heater assembly 10 comprises a heating chamber 12 for heating an aerosol-forming substrate. The heating chamber 12 has an elongated shape. The heating chamber 12 comprises a heating chamber wall 14 surrounding a cavity for insertion of the aerosol-forming substrate. The heating chamber wall 14 forms a hollow tube. The heater assembly 10 further comprises a heater casing 15. The heater casing 15 is coaxially disposed around the heating chamber 12. The heater casing 15 comprises a cylindrical heater casing wall 16. The heater casing 15 is further disposed radially away from the heating chamber 12 by a distance d. The distance d is measured radially between the outer diameter of the hollow tube formed by the heating chamber wall 14 and the inner diameter of the heater casing cylindrical wall 16. The heating chamber wall 14 and the heater casing wall 16 have matching shapes. Thereby, the distance d is constant along the longitudinal axis of the heating chamber 12. A microporous insulating material is disposed on the exterior of the heater casing.

[0154] The heater assembly 10 further comprises a first connecting wall 18 at a proximal end of the heater assembly 10. The heater assembly 10 further comprises a second connecting wall 20 at a distal end of the heater assembly 10. The first connecting wall 18 and the second connecting wall 20 are oriented perpendicular to the longitudinal axis of the heating chamber 12. In the particular embodiment of FIG. 1, the heater assembly 10 further comprises an airtight space 22. The airtight space 22 is defined between the heating chamber wall 14, the heater casing wall 16, and the first connecting wall 18 and the second connecting wall 20.

[0155] FIG. 2 shows one embodiment of a heating chamber 12 for a heater assembly. The heating chamber 12 includes a central region that includes a heating element. The heating element is disposed partially around the heating chamber 12. The wall 14 of the heating chamber is a metal tube. The heating element is flexible and wrapped around the metal tube. The heating element includes an electrically insulated flexible substrate 26 on which an electrically conductive heating track 24 is disposed. A proximal region 28 and a distal region 30 of the heating chamber 12 are longitudinally spaced away from the heating element.

[0156] Figure 3 shows one embodiment of a heater assembly 10 comprising the heating chamber 12 of Figure 2. A heating element is disposed between the heating chamber 12 and a heater casing 15.

[0157] The first connecting wall 18 and the second connecting wall 20 sealingly connect the heater casing wall 16 with the heating chamber wall 14, thereby enclosing the airtight space 22. The first connecting wall 18 and the second connecting wall 20 contact the heating chamber 12 at a position remote from the heating element. Therefore, the first connecting wall 18 and the second connecting wall 20 contact the heating chamber 12 at the coldest point of the heating chamber when heated in use. Thereby, heat losses due to heat transport from the heating chamber 12 to the connecting walls 18, 20 and the heater casing 15 by thermal conduction are reduced. However, the insulation of the heater assembly is further improved by a layer of microporous insulating material 101 arranged coaxially around the heater casing 15. The microporous insulating material contacts the outer surface of the heater casing wall 16 and is arranged coaxially around the heater casing. The microporous insulation material 101 may be, for example, MICROSIL microporous insulation manufactured by ZIRCAR Ceramics, Inc., Excelfrax® manufactured by Unifrax LLC, and Microtherm 1000 grade manufactured by Promat Inc, or other commercially available microporous insulation materials.

[0158] In the embodiment shown in Figure 3, the entire airtight space 22 is empty. However, in other embodiments, the airtight space may contain a second microporous insulating material. In still further embodiments, the gap between the heating chamber and the heater casing need not be an airtight space. In still further embodiments, the heating element may be disposed within the cavity defined by the heating chamber.

[0159] Although not shown, the microporous insulation material 101 shown in Figure 3 may also include one or more voids extending in a direction parallel to the longitudinal axis of the heating assembly. These voids may be in direct contact with the heater casing wall 16. These voids may have a shorter longitudinal extension than the microporous insulation material 32.

[0160] Figure 6 illustrates an alternative specific embodiment of a heater assembly 410. The heater assembly 410 is substantially similar to the heater assembly 10 illustrated in Figure 3, with the difference that a layer of microporous insulating material 401 disposed on the exterior of the heater casing 15 is separated from the heater casing wall 16 by a gap 402. The gap 402 may be an airtight gap.

[0161] Figure 5 illustrates the heater assembly 10 shown in Figure 3, where the heater assembly is installed as a component of an aerosol generating device. In the view of Figure 5, the outer surface of the microporous insulating material is placed in contact with at least a portion of the aerosol generating device housing 555. A user may, for example, lift the aerosol generating device and touch the housing. Heat transfer between the heater casing and the outer surface of the housing 555 is reduced by the presence of the microporous insulating material 101.

[0162] Figure 6 illustrates an alternative specific embodiment of a heater assembly 610. The heater assembly 610 is substantially similar to the heater assembly 10 illustrated in Figure 3, with the exception of the presence of a second layer of microporous insulating material 632. This second layer of microporous insulating material 632 is located within the cavity 22 and in direct contact with the heating chamber 12 and the heating element surrounding the heating chamber.

[0163] The microporous insulating material 101, 401 may be configured as a two-piece assembly. FIG. 7 shows a two-piece assembly of the microporous insulating material 101. Any of the heater assemblies 10, 410, 610 illustrated in FIG. 3, FIG. 4, FIG. 5, and FIG. 6 may comprise the two-piece assembly of FIG. 7. As can be seen in FIG. 7, the microporous insulating material 101 is formed from a first insulating element 736 having a first connecting element 740 and a second insulating element 738 having a second connecting element 742. The first connecting element 740 and the second connecting element 742 are configured as mating connecting elements. When the two first insulating element 736 and the second insulating element 738 are connected, the first connecting element 740 and the second connecting element 742 are connected to each other. The connection of the first connecting element 740 and the second connecting element 742 provides a direct contact of the first insulating element 736 and the second insulating element 738. The first insulating element 736 and the second insulating element 738 may have a hollow semi-cylindrical design as shown in FIG. 7, although other shapes and configurations are possible. When connected, the hollow semi-cylindrical design provides a hollow tube. The hollow tube may have an inner diameter the same as the outer diameter of the heater casing wall 16. This two-piece assembly allows the microporous insulating material 101 to have a perfect fit with the heater casing 15.

[0164] FIG. 8 shows an embodiment of an aerosol generating device 1 comprising the heater assembly 10 of FIG. 3. The aerosol generating device further comprises a power source 2. The power source 2 includes a power source 844 and control electronics 846. The power source 844 may be a rechargeable battery. In the embodiment of FIG. 8, the power source 2 and the heater assembly 10 are located in an outer housing 888 of the aerosol generating device 1. The outer surface of the microporous insulating material 101 of the heater assembly 10 is in contact with the inner surface of the outer housing 888. An aerosol-forming substrate may be at least partially inserted into the heating chamber of the heater assembly 10 through the opening 850. The aerosol-forming substrate may be part of an aerosol-generating article.

[0165] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like, should be understood in all instances as being modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A±10% of A. Within this context, the number A may be considered to include a numerical value that is within the general standard error for the measurement of the property that the number A modifies. The number A may, in some cases, as used in the appended claims, deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel properties of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. A heater assembly for an aerosol generating device, comprising: a heating chamber for heating the aerosol-forming substrate, the heating chamber being defined by a heating chamber wall; a heater casing disposed outside the heating chamber, the heater casing being defined by a heater casing wall; The heater assembly further comprises a microporous insulating material disposed on an exterior of the heater casing.

2. The heater assembly of claim 1 , wherein the heater casing is disposed about the heating chamber, e.g., the heater casing substantially surrounds the heating chamber.

3. The heater assembly of claim 1 or 2, wherein the microporous insulating material is disposed in contact with an exterior surface of the heater casing.

4. 3. A heater assembly as claimed in claim 1 or 2, wherein the microporous insulating material is substantially spaced from an external surface of the heater casing, for example by a distance of more than 0.01 mm, such as by a distance of about 0.1 mm to 5 mm, for example 0.5 mm to 4.5 mm, such as 1 mm to 4 mm, for example 1.5 mm to 3.5 mm, such as 2 mm to 3 mm, for example by a distance of about 2.5 mm.

5. The heater assembly of any one of claims 1 to 4, wherein the microporous insulating material substantially surrounds the heater casing.

6. 6. A heater assembly as described in any one of claims 1 to 5, wherein the microporous insulating material radially surrounds the heater casing, e.g., the heater casing has a substantially cylindrical outer surface and the microporous insulating material radially surrounds or encircles at least a central portion of the heater casing.

7. 7. A heater assembly according to any one of the preceding claims, wherein the microporous insulating material has a thickness of from 0.1mm to 5mm, such as from 0.5mm to 4.5mm, for example from 1mm to 4mm, such as from 1.5mm to 3.5mm, for example from 2mm to 3mm, such as about 2.5mm.

8. 8. The heater assembly of any one of claims 1 to 7, wherein the microporous insulating material has a thermal conductivity of less than 0.05 W / m K, preferably less than 0.04 W / m K, more preferably less than 0.03 W / m K at a temperature of 280 degrees Celsius.

9. 9. The heater assembly of claim 1, wherein the microporous insulating material is formed from at least a first insulating element including at least one first connecting element, and a second insulating element including at least one second connecting element, the first connecting element and the second connecting element being configured as mating connecting elements.

10. 10. The heater assembly of claim 9, wherein the first connecting element comprises a male connecting element and the second connecting element comprises a female connecting element.

11. 11. The heater assembly of claim 9 or 10, wherein the first connecting element and the second connecting element comprise form-fit connecting elements.

12. The heater assembly of any one of claims 9 to 11, wherein the first connecting element and the second connecting element comprise snap-fit ​​connecting elements.

13. The heater assembly of any one of claims 9 to 11, wherein the first connecting element and the second connecting element comprise bayonet connecting elements.

14. 14. The heater assembly of any one of claims 1 to 13, wherein the microporous insulating material is a first portion of microporous insulating material, and the heater assembly includes a second portion of microporous insulating material disposed between an interior surface of the heater casing and an exterior surface of the heating chamber.

15. 15. The heater assembly of claim 14, wherein the heater casing includes or defines an airtight space, e.g., the airtight space is defined between an inner surface of a wall of the heater casing and an outer surface of a wall of the heating chamber, the airtight space containing the second portion of microporous insulating material.

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