Aerosol generator with an easy-to-clean heated chamber

Abstract

The aerosol-generating device includes a heating chamber (30) for heating an aerosol-forming substrate. The heating chamber (30) is defined by a first end (32) having an opening, a second end (34) having a base (35), and a sidewall (31) extending substantially perpendicularly from the base (35). A peripheral portion of the base (35) is contoured to provide a chamfered or filleted intersection between the base (35) and the interior surfaces (35a, 35b) of the sidewall (31). [Selected figure] Figure 2a

Description

[Technical field]

[0001] The present invention relates to an aerosol generating device for heating an aerosol-forming substrate to form an inhalable aerosol, in particular to a device including a heating chamber that is easy to clean. [Background technology]

[0002] Devices for generating aerosols for inhalation by a user are known in the art. Such devices typically include a heating chamber for receiving an aerosol-generating article comprising an aerosol-forming substrate. Such devices also typically include a heater assembly configured to heat the aerosol-generating substrate in the heating chamber to generate an inhalable aerosol. For example, WO2013 / 102614 discloses an aerosol-generating device including a heating chamber for receiving an aerosol-generating article comprising a solid aerosol-forming substrate. In use, the aerosol-generating article is inserted into the heating chamber and thrust onto a heater disposed within the chamber. The heater can then be activated to heat the aerosol-forming substrate and generate an aerosol. After consumption, the aerosol-generating article is removed from the device and discarded.

[0003] The insertion, removal, and heating of the aerosol-forming substrate in such an aerosol-generating device typically produces residues, such as loose debris, in the heating chamber. Residues from the heating process may accumulate on the heaters, particularly on internal heaters that penetrate into the substrate. Residues may also accumulate on the inner walls of the heating chamber. Particles or fragments of the aerosol-forming substrate from the aerosol-generating article may become loose and be released into the heating chamber when the aerosol-forming substrate is inserted into or removed from the heating chamber. These forms of debris may accumulate in the heating chamber over time and with multiple uses of the device. In particular, debris may accumulate around the base or closed end of the heating chamber. If there is an internal heater, debris may also accumulate around the base of the heater. Accumulated debris may impede the effective operation of the device, for example, by absorbing some of the heat from the heater intended to heat the aerosol-forming substrate, by affecting the airflow through the device, or by impeding the insertion and removal of the aerosol-generating article.

[0004] The heating chamber of an aerosol generating device is usually sized and shaped to closely accommodate a portion of an aerosol generating article. Thus, for example, a heating chamber for accommodating the end of an aerosol generating article shaped like a conventional cigarette may be a cylindrical heating chamber having dimensions slightly larger than the outer dimensions of the end of the article. It is generally desirable to clean the heating chamber of an aerosol generating device between uses to minimize the accumulation of residue and debris. It is known to insert a brush into the heating chamber between uses to dislodge and remove accumulated residue. However, due to the generally small size of the heating chamber in an aerosol generating device, as well as the presence of sharp angles in the heating chamber, the brush may not be completely effective in removing accumulated residue. It would be desirable to make the cleaning more effective. Summary of the Invention

[0005] According to one aspect of the invention, there is provided an aerosol generating device for heating an aerosol-forming substrate to form an inhalable aerosol. The aerosol generating device comprises a heating chamber for heating the aerosol-forming substrate. The heating chamber includes a first end having an opening, a second end having a base, and a sidewall extending between the opening and the base, where a recess is defined by the base and an inner surface of the sidewall. A peripheral portion of the base is contoured to provide a chamfered or filleted intersection between the base and the inner surface of the sidewall.

[0006] As used herein, the term "intersection" refers to an area where two surfaces meet. For example, an intersection is formed in a heating chamber at the area where the inner surface of the sidewall meets the inner surface of the base. In some embodiments, the device can include a heater that extends through the base into the heating chamber, and an intersection may be formed at the area where the base meets the surface of the heater. An intersection, as used herein, generally refers to surfaces that meet at an angle of less than 180°. Such an intersection may be referred to as an internal angle. In a heating chamber of an aerosol generating device, such as the aerosol generating device of the present invention, an intersection between surfaces is generally about 90° because surfaces such as the inner surfaces of the base and sidewall typically extend substantially perpendicular to each other. An intersection having an angle of substantially 90° or less may be difficult to clean, as it may be difficult to insert a tool, such as a brush, into the small space created by such an acute angle.

[0007] It is desirable for the intersections between surfaces within the heating chamber to have angles greater than 90° to facilitate cleaning of the heating chamber. The intersections or interior angles between surfaces within the heating chamber may have angles greater than 90° and less than 180°.

[0008] The heating chambers disclosed herein have a contoured base such that the intersection between the base and the inner surface of the sidewall is chamfered or filleted. Such chamfered or filleted intersections may reduce the difficulty of cleaning the intersections between the base and the inner surface of the sidewall in the heating chamber.

[0009] As used herein, the term "chamfer" refers to a substantially straight transition edge between two surfaces. (transition area) By providing a straight transition edge between two surfaces that would otherwise meet at an acute interior angle (an intersection point with an angle less than 180°), the acute angle that would occur at the intersection point between the two surfaces can be replaced with two intersection points (a first intersection point between the first surface and the transition edge and a second intersection point between the second surface and the transition edge), each of which has an angle that is greater or less acute than the angle of the intersection point between the two surfaces.

[0010] For example, a heating chamber may have a base and a sidewall having interior surfaces that extend substantially perpendicular to one another and meet at a 90° angle intersection. However, if the base is contoured around its periphery to provide a chamfered intersection between the interior surfaces of the base and the sidewall, then in accordance with the present invention, a straight transition edge is provided between the base and the sidewall. If the angle of the straight transition edge around the periphery of the base relative to the general plane of the base is 135°, then the straight transition edge also intersects the sidewall at 135°. Thus, the chamfered intersection between the base and the sidewall is considered to have two 135° intersections, replacing the single 90° intersection between the base and the sidewall.

[0011] As used herein, the term "fillet" refers to a curved transition edge between two surfaces. (transition area) By providing a curved transition between two surfaces that would otherwise meet at a sharp intersection or interior angle, the sharp angle that would occur at the intersection between the two surfaces can be replaced with a curve that has a lower curvature than the sharp intersection between the two surfaces.

[0012] The chamfer or fillet provided by the contoured base effectively fills in areas that can be particularly difficult to clean, such as the intersection of the base and the interior surface of the sidewall.

[0013] The sidewall of the heating chamber may extend in a direction substantially perpendicular to the base. As used herein, the term "perpendicular" refers to a substantially orthogonal relative orientation of two components of a device or system, such as the relative orientation between the base and the sidewall of the heating chamber. Typically, the sidewall extends away from the base and substantially surrounds the base to define the recess of the heating chamber. In some embodiments, the sidewall may be physically connected to the base. In some embodiments, the base may be separable from the sidewall and movable relative to the sidewall.

[0014] Debris may accumulate at intersections or interior angles within the heating chamber, such as where the base meets the sidewall at the second closed end of the heating chamber and where the heater projects upward from the base. To clean debris from the heating chamber, a cleaning tool, such as a brush, can be inserted through an opening in the heating chamber and moved over the interior surface to remove loose debris and other residue. In existing devices, some of the interior angles or intersections within the heating chamber may have angles of 90° or less that are difficult to access with a cleaning tool. Thus, it may be difficult to properly remove accumulated debris from these heating chambers. In accordance with the present invention, if the peripheral portion of the base is contoured to provide chamfered or filleted intersections, the sharp angle intersections between the base and the sidewalls may be effectively filled. Filling the sharp angles that occur at the intersections between surfaces within the heating chamber allows a cleaning tool, such as a brush, to easily access all portions of the interior surface of the heating chamber, thereby helping to make the cleaning process faster and more efficient.

[0015] The peripheral portion of the base is the exterior or peripheral portion of the base around where the base meets or abuts the sidewall. The peripheral portion of the base is radially outward of the inner portion of the base. The inner portion of the base may be substantially planar or may extend in a substantially plane. The plane of the inner portion may be substantially perpendicular to the sidewall of the heating chamber. By contouring the peripheral portion such that it extends upward from the inner portion of the base that is chamfered with a straight edge, toward the opening of the heating chamber, the peripheral portion of the base can meet the sidewall of the heating chamber at a larger angle than it would without the contouring. By contouring the peripheral portion such that it extends upward from the inner portion of the base in a curve until it is substantially parallel to the sidewall (typically perpendicular to the base), toward the opening of the heating chamber, the peripheral portion can be parallel to the sidewall at the point where the two surfaces meet. Both types of contouring can prevent the formation of an acute angle between the inner surfaces of the base and the sidewall by creating a chamfered or filleted intersection between the inner surfaces of the base and the sidewall.

[0016] The angle created at the chamfered or filleted intersection is preferably greater than about 90°, greater than about 100°, greater than about 110°, greater than about 120°, or greater than about 135°. In other words, the chamfered or filleted intersections all provide relatively open angles, allowing easy access by the brush for cleaning. The brush can easily access the chamfered or filleted intersection to remove accumulated debris. In particular, the filleted intersection can be configured to have a concave curvature with a curvature that matches the curvature of the convex profile of the brush head. For example, the filleted intersection can be shaped to match the profile of a standard rounded brush. This ensures that the brush can reach all parts of the filleted intersection without having to be substantially deformed. This allows the brush to more easily reach all areas of the heating chamber, thus improving the cleaning efficiency of the brush.

[0017] The heating chamber of the present invention has at least one sidewall. When the heating chamber has a single sidewall, the sidewall may extend substantially around the periphery of the base. When the heating chamber has multiple sidewalls, the sidewalls may be arranged to extend substantially around the periphery of the base. The heating chamber may have any suitable number of sidewalls. Of course, references to features of a heating chamber having a single sidewall may equally apply to a heating chamber having multiple sidewalls.

[0018] The chamfered or filleted intersection between the base and the inner surface of the sidewall may extend substantially around the periphery of the base. The chamfered or filleted intersection may extend all the way around or to the entire periphery of the base. In this configuration, the intersection or corner between the base and the inner surface of the sidewall effectively fills around the entire periphery of the base, such that accumulated debris from any portion of the aerosol-generating article accumulates on the chamfer or fillet.

[0019] The opening of the heating chamber may be defined by a first end of the sidewall. For example, the sidewall may extend around the entire circumference of the base and may extend from the base in a substantially vertical direction, thereby forming a substantially cylindrical tube. The termination of the sidewall at the first end, opposite the base, may provide an opening, with the heating chamber defined within the tube, between the base and an inner surface of the sidewall. The opening is generally located opposite the base. In such an arrangement, the heating chamber may be configured to receive a portion of an aerosol-generating article resembling a traditional cigarette.

[0020] The base may be integrally formed with the sidewall of the heating chamber. In this configuration, there may be no spacing at all between the base and the sidewall. Thus, the device is easy to clean with a brush, since there are no orifices or openings around the perimeter of the base through which debris can fall or accumulate. Integral forming of the elements may also simplify manufacture and assembly of the device.

[0021] In some embodiments, the base is removable from the device. In this configuration, the base of the heating chamber can be completely removed from the heating chamber. Most of the debris accumulates on the base. Once the base is removed, it can be more easily cleaned by the user with a brush as the movement of the brush is not limited to the confines of the heating chamber. In some embodiments, the base can be reusable. The reusable base may be removed and cleaned, and the cleaned base may be reinserted into the heating chamber. In some embodiments, the base can be disposable. In these embodiments, the base may be discarded when removed from the heating chamber, the base may be removed from the heating chamber and discarded, and a new base may be inserted into the heating chamber. The base may be removable from the heating chamber and may be insertable into the heating chamber through an opening at a first end of the heating chamber. The aerosol-forming substrate may be insertable into the heating chamber through the same opening as the base. This configuration may allow the heating chamber to have a single opening, which may allow the heating chamber to have a simple structure. Additionally, for embodiments with a heater extending into the heating chamber, this configuration may limit the number of access points to the heating chamber for the user. This can substantially protect the user from contacting the heater while it is still hot.

[0022] The base may be removable from the heating chamber and may be insertable into the heating chamber through an opening in a sidewall of the heating chamber. The opening in the sidewall of the heating chamber may be adjacent a second end of the heating chamber. By providing an opening in the sidewall of the heating chamber, this second opening can be specifically configured for use with the base. By locating the opening adjacent the second end of the heating chamber, the longitudinal distance that the base must travel within the heating chamber when the residue collector is inserted or removed can be minimized.

[0023] In some embodiments where the base is removable, the base may include an engagement means for engaging with a removal tool. The tool may be any suitable tool for removing the base from the heating chamber. The engagement means may be a notch in at least one side of the base. In such embodiments, the tool may include a hook or clip for engaging with the notch such that the tool engages with the base and can be used to withdraw the base from the heating chamber. The engagement means may be a magnetic material disposed on at least a portion of the base. In such embodiments, the removal tool may include a magnetic material on one end for attracting the magnetic material of the base such that the tool can be used to withdraw the residue collector from the heating chamber.

[0024] The provision of a removal tool may eliminate the need for a user to directly touch the base during removal or insertion. This may be advantageous during removal of residue, such as debris, when it builds up on the base. The provision of a removal tool may also eliminate the need for a user to wait for the residue collector to cool before removing it from the heating chamber.

[0025] The entire periphery of the base may be contoured to provide a chamfered or filleted intersection between the base and the interior surface of the sidewall.

[0026] The base may be formed of any suitable material.

[0027] In some embodiments, the base may be formed of a metal. A metal base may have a melting point significantly higher than the temperature that occurs within the device during use. Thus, the heating process should not affect or damage the base over time. Additionally, the base may be formed of a metal with high thermal conductivity, so that the base can transfer heat to the aerosol-forming substrate when the heating chamber is heated. In some embodiments, debris that accumulates on the base may be less likely to adhere to the heated base. Thus, by providing a base with high thermal conductivity, the base may be more easily cleanable. Any suitable metal material may be used to form the base. Specific examples of suitable metals include aluminum or stainless steel.

[0028] In some embodiments, the base may be formed of a plastic material. A base formed of a plastic material may be conveniently manufactured by molding, which may be a cheap and simple manufacturing technique. Any suitable plastic material may be used to form the base. An exemplary suitable plastic material is PEEK.

[0029] The base may be provided with a coating, such as a low friction coating, which can further reduce adhesion of debris to the base.

[0030] The term "aerosol-forming substrate" as used herein relates to a substrate capable of releasing volatile compounds capable of forming an aerosol. The volatile compounds may be released upon heating of the aerosol-forming substrate. Suitable aerosol-forming substrates may include nicotine, plant-derived materials, homogenized plant-derived materials, or at least one aerosol former, or other additives or ingredients (such as flavorants). Suitable substrates may be in solid form, such as a tobacco plug. The tobacco plug may include one or more of powders, granules, pellets, pieces, spaghetti, strips, or sheets, including one or more of tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. Optionally, the tobacco plug may include additional tobacco or non-tobacco volatile flavor compounds that are released upon heating of the tobacco plug.

[0031] When the tobacco plug includes homogenized tobacco material, the homogenized tobacco material may be formed by agglomerating particulate tobacco. The homogenized tobacco material may be in the form of a sheet. The homogenized tobacco material may have an aerosol former content of greater than 5 percent on a dry weight basis. The aerosol former content of the homogenized tobacco material may be between 5 percent and 30 percent by weight on a dry weight basis. In some embodiments, the homogenized tobacco material sheet may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuted one or both of tobacco lamina and tobacco stems. In some embodiments, the homogenized tobacco material sheet may include one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed, for example, during tobacco processing, handling, and transportation. The homogenized tobacco material sheet may include one or more intrinsic binders (tobacco intrinsic binders), one or more extrinsic binders (tobacco extrinsic binders), or a combination thereof, to assist in agglomerating the particulate tobacco. In some embodiments, the homogenized tobacco material sheet may include other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof. The homogenized tobacco material sheet may be formed by a casting process of a type that generally involves casting a slurry including particulate tobacco and one or more binders onto a conveyor belt or other support surface, drying the cast slurry to form a homogenized tobacco material sheet, and removing the homogenized tobacco material sheet from the support surface.

[0032] The aerosol-forming substrate may be adsorbed, coated, impregnated or otherwise loaded onto a carrier or support.

[0033] The aerosol-forming substrate may be provided as part of an aerosol-generating article. The term "aerosol-generating article" as used herein relates to an article comprising an aerosol-forming substrate. The aerosol-generating article may be a non-combustible aerosol-generating article. A non-combustible aerosol-generating article is an article comprising an aerosol-forming substrate that has the ability to release volatile compounds without burning the aerosol-forming substrate, for example by heating the aerosol-forming substrate, by chemical reaction, or by mechanical stimulation of the aerosol-forming substrate. The aerosol-generating article may be a smoking article that generates an aerosol that can be inhaled directly through the mouth of a user into the lungs of the user. The aerosol-generating article may resemble a conventional smoking article, such as a cigarette. The aerosol-generating article may be disposable. The aerosol-generating article may be partially reusable and may comprise a refillable or replaceable aerosol-forming substrate.

[0034] As used herein, "aerosol generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol generating device may include one or more components that are used to provide energy from a power source to an aerosol generating means for interacting with the aerosol-forming substrate to generate an aerosol that can be inhaled by a user. The power source may be an external source or may form part of the device, such as an on-board battery. The aerosol generating means may be any suitable means for generating an aerosol from an aerosol-forming substrate. For example, the aerosol generating means may be an electric heater.

[0035] The aerosol generating device may include an aerosol generating means, which may be any suitable aerosol generating means. For example, the aerosol generating means may include a heater configured to heat an aerosol-forming substrate received in a heating chamber of the device. The heater may be configured to heat the aerosol-forming substrate to generate an aerosol for inhalation by a user. The heater may be any suitable type of heater.

[0036] The heater may extend into the heating chamber. The heater may extend through the base into the heating chamber. The heater may be centrally located in the heating chamber or may extend through a central portion of the base. A heater extending into the heating chamber may be arranged to penetrate an aerosol-forming substrate received in the heating chamber. This type of heater may be referred to as an internal heater. As used herein, "internal heater" refers to a heater configured to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is received in the heating chamber. The internal heater may be inserted into the aerosol-forming substrate to directly contact the aerosol-forming substrate in the aerosol-generating article. The internal heater is configured to heat the aerosol-forming substrate of the aerosol-generating article from the inside. The use of an internal heater may be advantageous since it may be in direct contact with the aerosol-forming substrate to efficiently heat the substrate. The inner portion of the base may be a relatively flat or planar portion. The inner portion of the base is located radially inward of the peripheral portion of the base.

[0037] In embodiments that include a heater that extends through a base into the heating chamber, the base is contoured to provide a chamfered or filleted intersection between the base and at least one surface of the heater. This configuration effectively fills the intersection between the bottom of the base and one or more surfaces of the heater as the heater projects outward from the base. If the heater extends through the base into the heating chamber substantially perpendicular to the base, the intersection between the heater's surface and the base has a 90° angle. If the heater extends through the base at an angle other than 90°, the intersection between the heater's surface and the base varies between the sides of the heater, and on one side, there may be an acute angle between the heater and the base. In both of these configurations, it may be difficult to clean debris that accumulates in the intersection with a cleaning tool such as a brush. By providing a chamfer or fillet at the intersection, the acute angle is filled. The angle of a chamfered or filleted intersection may be relatively open, making it easier to access with a cleaning tool such as a brush for cleaning. In other words, the brush can more easily access the chamfered or filleted intersections to dislodge accumulated debris.

[0038] The heater may extend into the heating chamber in a direction substantially parallel to the sidewall. The heater may extend substantially parallel to the longitudinal axis of the tubular or cylindrical heating chamber. The heater may extend along a portion of the length of the heating chamber. In some embodiments, the heater may extend substantially the entire length of the heating chamber. When the aerosol-forming substrate is inserted into the heating chamber, the heater may be positioned to be in direct contact with a large proportion of the aerosol-forming substrate. As used herein, "length" refers to the maximum longitudinal dimension of the device, substrate or portion or portion of the device or substrate, such as the distance between the second end of the heating chamber and the first end of the heating chamber (i.e., the distance between the base and the opening).

[0039] The heater may be centrally located within the heating chamber. In other words, the heater may extend substantially along the central longitudinal axis of the heating chamber. In this configuration, the maximum temperature generated within the heating chamber at the heater may occur along the central longitudinal axis of the heating chamber. In this configuration, the heater may be positioned to heat the aerosol-forming substrate within the heating chamber from a central region outwardly, and to heat all sides of the aerosol-forming substrate evenly. The heater may be positioned substantially equidistant from the sidewalls of the heating chamber on all sides.

[0040] In some embodiments, the heater may extend into the heating chamber substantially perpendicular to the sidewall. In such configurations, the heater may extend transversely across the elongated heating chamber. As used herein, the term "transverse" refers to a direction perpendicular to the device, substrate, or a portion or part of the device or substrate, such as a direction perpendicular to the longitudinal axis of the heating chamber.

[0041] The heater may be an external heater. As used herein, "external heater" refers to a heater that does not penetrate the aerosol-forming substrate in the heating chamber or any part of the aerosol-generating article received in the heating chamber. The external heater may be located on or around the inner surface of the heating chamber. In some embodiments, the external heater may contact the outer surface of the aerosol-generating article received in the heating chamber. In some embodiments, the external heater may not directly or physically contact the aerosol-forming substrate or any part of the aerosol-generating article received in the heating chamber. The external heater may be located within the aerosol generating device but outside or external to the heating chamber. A heating chamber with an external heater may be referred to as an oven, and an external heater may be referred to as an oven heater.

[0042] The heater may be any suitable type of heater. For example, the heater may be an electrically resistive heating element. Such a heating element may be directly connected to the power supply of the device, and electrical current from the power supply of the device may be directly converted to heat in the resistive heating element. This type of heater may minimize the number of components required in the device.

[0043] The heater may be part of a heating assembly. The heating assembly may be any suitable type of heating assembly. For example, the heating assembly may be an electric heating assembly. If the heating assembly is an electric heating assembly, the aerosol generating device may also include a power source for providing power to the heating assembly.

[0044] Of course, there are many heating assemblies that may be used. For example, the heating assembly may include a heater in the form of a susceptor element that extends into the heating chamber, and the heating assembly may further include an inductor disposed in or around the heating chamber configured to heat the susceptor. For example, the inductor may include a coil disposed outside the heating chamber or surrounding the heating chamber that acts to induce a heating current in the susceptor. Certain embodiments will now be discussed in detail and are shown by way of example only in the following figures. [Brief description of the drawings]

[0045] [Figure 1a] FIG. 1a shows a cutaway view of a conventional internally heated heating chamber. [Figure 1b] FIG. 1b shows the heating chamber of FIG. 1a including a brush. [Figure 2a] FIG. 2a shows a cutaway view of an internally heated heating chamber according to an embodiment of the present invention. [Figure 2b] FIG. 2b shows the heating chamber of FIG. 2a including a brush. [Figure 3a] FIG. 3a shows a side view of a removable base according to a second embodiment of the present invention disposed around a heater blade. [Figure 3b]FIG. 3b shows a top view of a removable base according to a second embodiment of the present invention. [Figure 3c] FIG. 3c shows a perspective view of a removable base according to a second embodiment of the present invention disposed around a heater blade. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] FIG. 1a is a schematic diagram of a heating chamber 10 of an aerosol generating device. The heating chamber 10 is configured to receive and heat an aerosol-forming substrate. The heating chamber 10 includes a first end 12 having an opening 13, a second end 14 having a base 15, and a sidewall 11 extending between the opening 13 and the base 15. The sidewall 11 is an annular cylindrical tube substantially closed at the second end 14 by the base 15, which is generally in the form of a planar circular disk. A recess 17 is defined by the interior surfaces of the base 15 and the sidewall 11. The heating chamber 10 is configured to receive an aerosol-forming substrate in the recess 17 through the opening 13 in the first end 12.

[0047] The heating chamber 10 includes an internal heater 18 in the form of an elongated, planar heating blade terminating in opposing first and second sides 18a and a point 18b. The opposing first and second sides 18a of the heater 18 are defined by a width and a length of the heater 18. The length dimension of the heater 18 is greater than its width dimension, which is greater than its thickness dimension. The heater 18 extends from the base 15 into a recess 17 at the closed second end 14 of the heating chamber 10. The heater 18 is generally aligned along a central longitudinal axis of the heating chamber 10, perpendicular to the base 15 and parallel to the sidewall 11.

[0048] An aerosol-forming substrate (not shown), such as a tobacco rod, is typically provided as part of the aerosol-generating article, with the aerosol-forming substrate at the distal end and a filter at the proximal end. In use, the aerosol-forming substrate is inserted into the recess 17 through the open end 12 of the heating chamber 10 such that the tapered point 18b of the heater 18 engages the substrate. By applying a force to the aerosol-generating article, the heater 18 penetrates into the aerosol-forming substrate. When the aerosol-generating article is fully engaged with the aerosol generating device, the aerosol-forming substrate is substantially received within the recess 17 and the heater 18 is surrounded by the aerosol-forming substrate. When the heater 18 is activated, the aerosol-forming substrate is heated by the heater 18 and volatile substances are generated or released as vapor from the substrate. When a user draws on the mouthpiece of the article, air is drawn into the aerosol-generating article and the volatile substances condense to form an inhalable aerosol. The aerosol becomes trapped in the air drawn through the aerosol-generating article, through the mouthpiece of the aerosol-generating article, and into the user's mouth.

[0049] During insertion and removal of the aerosol-forming substrate into and from the recess 17 of the heating chamber 10, loose substrate may be released into the chamber 17 and form undesirable debris 22 at the base 15. Residue from the substrate (not shown) may also accumulate on the surface 18a of the heater 18. In Figures 1a and 1b, debris 22 is shown accumulating within the heating chamber 10 at the intersection 25 between the interior surface of the base 15 and the interior surface of the sidewall 11. Debris 22 is also shown accumulating at the intersection 27 between the interior surface of the base 15 and the surface 18a of the heater 18.

[0050] A tool such as a brush may be provided to clean debris 22 from the heating chamber 10 and residue from the heater 18. In FIG. 1b, a cleaning brush 28 is shown in the heating chamber 10. The head of the brush 28 has a circular longitudinal cross section. Because the heating chamber has a substantially rectangular cross section at the second end 14, the bristles (not shown) of the brush 28 do not reach the corners or intersections 25, 27 of the heating chamber 10. The bristles of the brush 28 may be deformable to allow some of the bristles to reach the intersections 25, 27 of the heating chamber 10. However, deforming the bristles of the brush 28 to reach the intersections 25, 27 may unacceptably increase the effort required by a user to clean the heating chamber 10, damage the brush, or reduce the efficiency of the brush by requiring the bristles to be softer or more deformable.

[0051] In Fig. 2a, a heating chamber 30 according to an embodiment of the present invention is shown. The heating chamber 30 is substantially similar to the heating chamber 10 of Fig. 1a, having a sidewall 31 identical to the sidewall 11, a first end 32 identical to the first end 12, and a heater 38 identical to the heater 18. However, the heating chamber 30 has a base 35 at a second end 34 that is contoured around its periphery to form a chamfer 35a around the outer edge of the base 35 between the inner surface of the base 35 and the sidewall 31. The chamfer 35a is a substantially straight edge that extends between the inner surface of the base 35 and the inner surface of the sidewall 31, effectively filling the intersection between the inner surface of the base 35 and the inner surface of the outer wall 31. The chamber 35a extends upwardly at an angle of about 135° from the general plane of the base 35. The outer end of chamfer 35a abuts the inner surface of sidewall 31 around the entire circumference of sidewall 31 at an angle of approximately 135°. Base 35 is further contoured in a central region to create an internal chamfer 35b between the inner surface of base 35 and surface 38a of heater 38. Internal chamfer 35b extends between the inner surface of base 35 and heater blade surface 38a, effectively filling the intersection between the inner surface of base 35 and heater surface 38a. Internal chamfer 35b extends upwardly from the general plane of the base at an angle of approximately 135°, and the inner end of internal chamfer 35b abuts heater surface 38a at an angle of approximately 135° around the entire circumference of the lower portion of the heater.

[0052] In Figure 2b, brush 28 is shown within heating chamber 30. The circular profile of brush 28 closely corresponds to the profile of the interior surface of base 35, particularly at chamfers 35a, 35b. When brush 28 is inserted into heating chamber 30, brush bristles (not shown) can contact the entire surface of chamfers 35a, 35b. Brush 28 can therefore remove debris and residue from all of the interior surfaces of the heating chamber, including the entire surface of chamfers 35a, 35b.

[0053] In the embodiment of Figures 2a and 2b, the base 35 is integrally formed with the outer wall 31 which defines the heating chamber.

[0054] An alternative embodiment is shown in Figures 3a, 3b and 3c in which a base 55 is removable from a heating chamber 50. The heating chamber 50 in this embodiment has a closed second end 54 defined by an end portion 54a. Figure 3a shows the removable base 55 positioned within the heating chamber at the closed second end 55 (sidewalls removed to show the base in situ). The base 55 is a substantially planar, disk-shaped element with a raised peripheral edge forming an outer fillet end 55a and a raised central portion around a central slot 55c forming an inner fillet end 55b. In this embodiment, the base 55 includes fillets rather than chamfers at the periphery and central region. The fillets 55a, 55b provide curved edges at the intersections between the interior surfaces of the base 55 and the sidewalls (not shown) and the interior surfaces of the base 55 and the heater 58.

[0055] Slot 55c is positioned or dimensioned to receive an elongated, planar heating blade 58 such that an inner end of internal fillet 55b abuts lower surface 58a of heating element 58. Base 55 includes a circular raised lip 55d projecting downwardly from an underside of base 55 to engage end 54a of heating chamber 50 and space the underside of base 55 from end 54a. Of course, in other embodiments, the circular lip may be replaced with multiple leg elements, such as, for example, three or four leg elements evenly spaced around the base.

[0056] In this embodiment, the internal fillet 55b does not extend around the entire circumference of the heater 58. In this embodiment, the base 55 does not bulge at the narrow end 58c of the heater 58 because there is little debris accumulation at the narrow end 58c. In other words, the height of the internal fillet 55b varies around the circumference of the heater 58. The height of the internal fillet 55b gradually rises from the narrow end 58c of the heater 58 across the surfaces 58a of the heater 58 toward the center of each surface 58a, providing a curved fillet profile across the surfaces 58a of the heater 58. Of course, in other embodiments, the internal fillet 55b may extend around the entire circumference of the heater 58 or have any other suitable profile across the surfaces 58a of the heater.

[0057] The removable base 55 is inserted into the heating chamber 50 through the open end (not shown) of the heating chamber 50. The heater 58 is received in the slot 55c and the base 55 is lowered into the recess of the heating chamber 50 until the base 55 is in place at the closed end 54, with the raised lip 55d abutting the end 54a of the heating chamber 50. When the base 55 is so positioned, the device is ready for use. To remove the base 55 from the heating chamber 50, a removal tool (not shown) can be inserted into the heating chamber 50 and engaged with the base 55 by the removal notches 55e around the periphery of the base 55. The tool can be hooked under the base 55 or attached to the base 55 at the notches 55e, and the user can pull the tool and base 55 out of the heating chamber 50. The base 55 may be cleaned and replaced within the heating chamber 50, or may be discarded and a new base 55 inserted into the heating chamber 50, as described above.

[0058] Of course, both the integral and removable bases may include chamfered or filleted junctions, in some embodiments, the base may include a chamfered junction on one of the exterior and interior junctions and a filleted junction on the other of the exterior and interior junctions.

Claims

1. 1. An aerosol generating device for generating an inhalable aerosol by heating an aerosol-forming substrate, comprising: A heating chamber for heating an aerosol-forming substrate, the heating chamber including a first end having an opening, a second end having a base, and a sidewall extending between the opening and the base; a recess is defined by the base and an inner surface of the sidewall, and a connection between the base and the inner surface of the sidewall is contoured to provide a substantially straight or curved transition region; The aerosol generating device, wherein the device further comprises a heating assembly and a power source.

2. 2. The aerosol generating device of claim 1, wherein the sidewall extends substantially perpendicular to the base.

3. 3. The aerosol generating device of claim 1, wherein the transition region extends substantially around a periphery of the base.

4. 2. The aerosol generating device of claim 1, wherein the heating assembly comprises a heater extending through an inner portion of the base into the heating chamber, and a connection between the inner portion of the base and the heater is contoured to provide a substantially straight or curved transition region.

5. 5. The aerosol generating device of claim 4, wherein the heater is a resistive heater or an inductive heater.

6. 5. The aerosol generating device of claim 4, wherein the heater is a susceptor and the heating assembly further comprises an inductor coil.

7. 7. An aerosol generating device according to claim 4, wherein the heater extends substantially within the heating chamber in a direction parallel to the side wall.

8. The aerosol generating device of claim 1 , wherein the heating assembly comprises an external heater.

9. 9. The aerosol generating device according to claim 1, wherein the opening of the heating chamber is defined by the side wall, and the opening is configured to face the base.

10. 10. An aerosol generating device according to any one of claims 1 to 9, wherein the base is integrally formed with a side wall of the heating chamber.

11. An aerosol generating device according to any one of claims 1 to 9, wherein the base is removable from the device.

12. 12. The aerosol generating device of claim 11, wherein the base is removable and insertable through the opening in the first end of the heating chamber.

13. 12. The aerosol generating device of claim 11, wherein the base is removable and insertable through the opening in a sidewall of the heating chamber adjacent the second end of the heating chamber.

14. An aerosol generating device according to any one of claims 11 to 13, wherein the base has engagement means for engaging with a removal tool.

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