Aerosol generator equipped with a heating chamber that is easy to clean

Abstract

To provide an aerosol generation device including a heating chamber that is easy to be cleaned.SOLUTION: An aerosol generation device includes a heating chamber 30 for heating an aerosol forming base body. The heating chamber 30 is defined by a first end 32 having an opening, a second end 34 having a base part 35, and a side wall 31 extending substantially perpendicularly from the base part 35. A peripheral portion of the base part 35 is a contour providing a chamfered or fillet intersection of the base part 35 and the side wall 31 in between inner surfaces 35a, 35b.SELECTED DRAWING: 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, the present invention relates to a device including a heating chamber that is easy to clean.

Background Art

[0002] Devices for generating an aerosol for inhalation by a user are known in the art. Such devices typically include a heating chamber that receives an aerosol-generating article containing an aerosol-forming substrate. Such devices also typically include a heater assembly configured to heat the aerosol-forming substrate within 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 containing a solid aerosol-forming substrate. In use, the aerosol-generating article is inserted into the heating chamber and impaled on a heater disposed within the chamber. Thereafter, the heater is 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] Insertion, removal, and heating of an aerosol-forming substrate within such an aerosol-generating device typically generate residues such as debris that are free within the heating chamber. Residues from the heating process can accumulate on the heater, particularly on an internal heater that penetrates into the substrate. Residues can also accumulate on the inner wall of the heating chamber. Particles or fragments of the aerosol-forming substrate from the aerosol-generating article can be released and discharged into the heating chamber when the aerosol-forming substrate is inserted into the heating chamber or removed from the heating chamber. The form of these fragments can accumulate within the heating chamber over time and with multiple uses of the device. In particular, the fragments can accumulate around the base or closed end of the heating chamber. Where there is an internal heater, the fragments can also accumulate around the base of the heater. The accumulated fragments can, for example, impede the effective operation of the device 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 typically sized and shaped to closely accommodate a portion of the aerosol-generating article. Thus, for example, a heating chamber for accommodating the end of an aerosol-generating article shaped like a conventional cigarette can be a cylindrical heating chamber having dimensions slightly larger than the outer dimensions of the end of the article. Generally, it is desirable to clean the heating chamber of the aerosol-generating device between uses to minimize the accumulation of residues and fragments. It is known to insert a brush into the heating chamber between uses to remove the accumulated residues. However, due to the generally small size of the heating chamber within the aerosol-generating device and the presence of sharp corners within the heating chamber, the brush may not be completely effective in removing the accumulated residues. It becomes desirable to make the cleaning more effective. SUMMARY OF THE INVENTION

[0005] According to one aspect of the present 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 side wall extending between the opening and the base, wherein a recess is defined by the base and the inner surface of the side wall. The peripheral portion of the base is contoured to provide a chamfered or filleted intersection between the base and the inner surface of the side wall.

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

[0007] It is desirable for the intersection between the surfaces in the heating chamber to have an angle greater than 90° to facilitate cleaning of the heating chamber. The intersection or internal angle between the surfaces in the heating chamber can have an angle greater than 90° and less than 180°.

[0008] The heating chamber disclosed herein has a contoured base such that the intersection between the base and the inner surface of the sidewall is contoured as chamfered or filleted. Such chamfered or filleted intersections can reduce the difficulty of cleaning the intersection between the base and the inner surface of the sidewall within the heating chamber.

[0009] As used herein, the term "chamfer" relates to a substantially linear transition edge between two faces. (Migration area) Otherwise, by providing a linear transition edge between two surfaces that meet at a sharp interior angle (an intersection angle of less than 180°), the acute angle that would occur at the intersection between the two surfaces can be replaced by two intersections (a first intersection between the first surface and the transition edge and a second intersection between the second surface and the transition edge), each of which has an angle greater than or not as sharp as the angle of the intersection between the two surfaces.

[0010] For example, the heating chamber can have a base and a sidewall with inner surfaces that extend substantially perpendicular to each other and meet at an intersection angle of 90°. However, if the base is contoured such that it provides a chamfered intersection between the base and the inner surface of the sidewall around its perimeter, according to the present invention, a linear transition edge is provided between the base and the sidewall. If the angle of the linear transition edge around the perimeter of the base with respect to the general plane of the base is 135°, the linear transition edge also intersects the sidewall at 135°. Thus, the chamfered intersection between the base and the sidewall is considered to have two intersections at 135°, replacing the single intersection between the base and the sidewall at 90°.

[0011] As used herein, the term "fillet" relates to a curved transition edge between two surfaces. (Migration area) Otherwise, by providing a curved transition edge between two surfaces that meet at a sharp intersection or interior angle, the acute angle that would occur at the intersection between the two surfaces can be replaced by a curve having a lower curvature than the sharp intersection between the two surfaces.

[0012] The chamfer or fillet provided by the contoured base effectively fills the portion of the intersection of the inner surface of the base and the side wall that can be particularly difficult to clean.

[0013] The side walls of the heating chamber may extend in a direction substantially perpendicular to the base. As used herein, the term "perpendicular" relates to the substantially orthogonal relative orientation of two parts of an apparatus or system, such as the relative orientation between the base and the side walls of the heating chamber. Typically, the side walls extend away from the base and substantially surround the base to define the recess of the heating chamber. In some embodiments, the side walls may be physically connected to the base. In some embodiments, the base is separable from the side walls and may be movable relative to the side walls.

[0014] Debris can accumulate at intersections or internal corners within the heating chamber, such as at the portion where the base contacts the side wall at the second closed end of the heating chamber and at the portion 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 the opening of the heating chamber and moved over the inner surface to remove residues such as loose debris. In existing devices, some of the internal corners or intersections within the heating chamber can have an angle of 90 degrees or less, which makes access with a cleaning tool difficult. Thus, it can be difficult to properly remove accumulated debris from these heating chambers. According to the present invention, when the peripheral portion of the base is contoured to provide a chamfered or filleted intersection, the sharp-angled intersection between the base and the side wall can be effectively filled. By filling the acute angles that occur at the intersections between the surfaces within the heating chamber, a cleaning tool such as a brush can easily access all parts of the inner surface of the heating chamber, thereby assisting in making the cleaning process quicker and more efficient.

[0015] The peripheral portion of the base is the outer or surrounding portion of the base around the portion where the base contacts or abuts the side wall. The peripheral portion of the base is radially outside the inner portion of the base. The inner portion of the base may be substantially planar or may extend substantially planar. The plane of the inner portion may be substantially perpendicular to the side wall of the heating chamber. By contoured the peripheral portion so that it extends upwardly from the inner portion of the base chamfered with a straight edge towards the opening of the heating chamber, the peripheral portion of the base can contact the side wall of the heating chamber at a larger angle than without contouring. By contoured the peripheral portion so that it extends upwardly from the inner portion of the base in a curve towards the opening of the heating chamber and becomes substantially parallel (typically perpendicular to the base) to the side wall, the peripheral portion can be parallel to the side wall at the point where the two surfaces meet. Both types of contours can prevent an acute angle from being formed between the inner surfaces of the base and the side wall by creating a chamfered or filleted intersection between the base and the inner surface of the side wall.

[0016] The angle formed at the chamfered intersection 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 and are easily accessible by a brush for cleaning. The brush can easily access and remove debris accumulated at the chamfered or filleted intersections. In particular, the filleted intersection can be configured to have a concave curvature that matches the curvature of the convex outer shape of the brush head. For example, the filleted intersection may be shaped to match the outer shape of a standard rounded brush. This ensures that the brush reaches all parts of the filleted intersection without substantial deformation. Thereby, the brush can more easily reach all areas of the heating chamber, and thus the cleaning efficiency by the brush can be improved.

[0017] The heating chamber of the present invention has at least one side wall. If the heating chamber has a single side wall, the side wall can extend substantially around the perimeter of the base. If the heating chamber has multiple side walls, the side walls can be arranged to extend substantially around the perimeter of the base. The heating chamber can have any suitable number of side walls. Of course, references to the features of a heating chamber with a single side wall can equally apply to a heating chamber with multiple side walls.

[0018] The chamfered or filleted intersection between the base and the inner surface of the side wall may extend substantially around the perimeter of the base. The chamfered or filleted intersection may extend around the entire perimeter of the base. In this configuration, the intersection or corner between the base and the inner surface of the side wall effectively fills around the entire circumference of the base, so that debris accumulated from any part of the aerosol generating article accumulates on the chamfer or fillet.

[0019] The opening of the heating chamber can be defined by the first end of the side wall. For example, the side wall may extend around the entire perimeter of the base and may extend substantially vertically from the base, thereby forming a substantially cylindrical tube. The termination of the side wall at the first end, opposite the base, can provide an opening between the base and the inner surface of the side wall with the heating chamber defined within the tube. The opening is generally located on the opposite side of the base. In such an arrangement, the heating chamber can be configured to receive a portion of the aerosol generating article that resembles a conventional cigarette.

[0020] The base can be integrally formed with the side wall of the heating chamber. In this configuration, there may be no gap between the base and the side wall. Thus, since there are no orifices or openings for debris to fall or accumulate around the perimeter of the base, the device is easy to clean with a brush. Integrally forming the elements can also simplify the 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. When the base is removed, the movement of the brush is not limited within the range of the heating chamber, so the user can more easily clean it with the brush. In some embodiments, the base may be reusable. The reusable base can be removed and cleaned, and the cleaned base can be reinserted into the heating chamber. In some embodiments, the base may be disposable. In these embodiments, the base may be discarded when removed from the heating chamber, the base is removed from the heating chamber and discarded, and a new base can be inserted into the heating chamber. The base can be removable from the heating chamber and can be inserted into the heating chamber through an opening at the first end of the heating chamber. The aerosol-forming substrate can be inserted into the heating chamber through the same opening as the base. This configuration can enable the heating chamber to have a single opening, which can enable the heating chamber to have a simple structure. In addition, for embodiments including a heater extending into the heating chamber, this configuration can limit the number of user access points to the heating chamber. This can substantially protect the user from contacting the heater when the heater is still hot.

[0022] The base can be removable from the heating chamber and can be inserted into the heating chamber through an opening in the side wall of the heating chamber. The opening in the side wall of the heating chamber can be adjacent to the second end of the heating chamber. By providing an opening in the side wall of the heating chamber, this second opening can be specifically configured for use with the base. By positioning the opening adjacent to the second end of the heating chamber, the longitudinal distance that the base has to move within the heating chamber when the residue collection device is inserted or removed can be minimized.

[0023] In some embodiments where the base is removable, the base may include engagement means for engaging with a removal tool. The tool can be any suitable tool for removing the base from the heating chamber. The engagement means can be a notch on 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 is used to engage with the base and pull the base out of the heating chamber. The engagement means can be a magnetic material disposed on at least a portion of the base. In such embodiments, the removal tool may include a magnetic material at one end for attracting the magnetic material of the base such that the tool can be used to pull the residue collection device out of the heating chamber.

[0024] The provision of a removal tool can eliminate the need for the user to directly touch the base during removal or insertion. This can be advantageous when removing residues such as fragments that have accumulated on the base. The provision of a removal tool can also eliminate the need for the user to wait for the residue collection device to cool before removing it from the heating chamber.

[0025] The entire peripheral portion of the base can be contoured to provide a chamfered or filleted intersection between the base and the inner surface of the side wall.

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

[0027] In some embodiments, the base may be formed of metal. The metal base may have a melting point significantly higher than the temperature generated within the device during use. Thus, the heating process should not affect or damage the base over time. Further, the base may be formed of a metal having a high thermal conductivity, such that the base can transfer heat to the aerosol-forming substrate when the heating chamber is heated. In some embodiments, the likelihood that debris accumulating on the base adheres to the heated base may be reduced. Thus, by providing a base having a high thermal conductivity, the base may be more easily cleanable. Any metal material suitable for forming the base may be used. 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 can be conveniently manufactured by molding. This can be an inexpensive and simple manufacturing technique. Any plastic material suitable for forming the base may be used. An exemplary suitable plastic material is PEEK.

[0029] The base may be provided with a coating such as a low-friction coating, thereby further reducing the adhesion of debris to the base.

[0030] As used herein, the term "aerosol-forming substrate" relates to a substrate having the ability to release volatile compounds capable of forming an aerosol. The volatile compounds may be released by heating 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, fragments, spaghetti, shreds, or sheets, including one or more of tobacco leaves, fragments of tobacco stems, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. Optionally, the tobacco plug may include additional tobacco or non-tobacco volatile flavor compounds released upon heating of the tobacco plug.

[0031] When the tobacco plug contains a homogenized tobacco material, the homogenized tobacco material may be formed by aggregating 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 more than 5 percent on a dry mass basis. The content of the aerosol former in the homogenized tobacco material may be from 5 percent to 30 weight percent on a dry mass basis. In some embodiments, the homogenized tobacco material sheet may be formed by aggregating particulate tobacco obtained by grinding or otherwise subdividing one or both of tobacco leaf laminas and tobacco leaf stems. In some embodiments, the homogenized tobacco material sheet may include one or more of, for example, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the processing, handling, and transportation of tobacco. The homogenized tobacco material sheet may include one or more endogenous binders (tobacco endogenous binders), one or more exogenous binders (tobacco exogenous binders), or combinations thereof to assist in aggregating the particulate tobacco. In some embodiments, the homogenized tobacco material sheet may include, but is not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and other additives including combinations thereof. The homogenized tobacco material sheet can be formed by a casting process of the general type that generally includes casting a slurry containing particulate tobacco and one or more binders onto a conveyor belt or other support surface, drying the cast slurry to form the 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. As used herein, the term "aerosol-generating article" 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 a volatile compound without burning the aerosol-forming substrate, for example by heating the aerosol-forming substrate, by a 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 into the user's lungs through the user's mouth. 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 include a refillable or replaceable aerosol-forming substrate.

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

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

[0036] The heater may extend into the heating chamber. The heater may extend into the heating chamber through the base. The heater may be disposed at the center within the heating chamber and may extend through the central portion of the base. The heater extending into the heating chamber may be arranged to penetrate the aerosol-forming substrate received within the heating chamber. This type of heater may be referred to as an internal heater. As used herein, an "internal heater" relates to a heater configured to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is received within the heating chamber. The internal heater may be inserted into the aerosol-forming substrate to directly contact the aerosol-forming substrate within 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 because it can directly contact 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 extending into the heating chamber through the base, the base has a contour that provides a chamfered or filleted intersection or intersection between at least one surface of the base and the heater. This configuration effectively fills the intersection between the bottom of the base and one or more surfaces of the heater when the heater projects outwardly from the base. When the heater extends into the heating chamber substantially at a right angle to the base through the base, the intersection between the surface of the heater and the base has a 90° angle. When the heater extends through the base at an angle other than 90°, the intersection between the surface of the heater and the base varies between the sides of the heater, and on one side, an acute angle may exist between the heater and the base. In both of these configurations, it may be difficult to clean debris accumulating within the intersection with a cleaning tool such as a brush. By providing a chamfer or fillet at the intersection, the acute angle is filled. Since the angle of the chamfered or filleted intersection is relatively open, it may be easy to access with a cleaning tool such as a brush for cleaning. In other words, the brush can easily access and remove accumulated debris due to the chamfered or filleted intersection.

[0038] The heater may extend into the heating chamber in a direction substantially parallel to the side wall. The heater may extend substantially parallel to the longitudinal axis of a 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 arranged 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 a device, substrate, or portion or part of a 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 located centrally 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 highest temperature generated within the heating chamber by the heater can occur along the central longitudinal axis of the heating chamber. In this configuration, the heater may be arranged to heat the aerosol-forming substrate within the heating chamber outwardly from the central region and to evenly heat all sides of the aerosol-forming substrate. The heater may be arranged at substantially equal distances from the side walls of the heating chamber on all sides.

[0040] In some embodiments, the heater may extend into the heating chamber substantially at right angles to the side walls. In such a configuration, the heater may extend transversely across the elongate heating chamber. As used herein, the term "transverse direction" relates to a direction that is at right angles to the longitudinal axis of the heating chamber, such as a direction that is at right angles to the device, the substrate, or a part or portion of the device or substrate.

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

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

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

[0044] Of course, there are many heating assemblies that can be used. For example, the heating assembly may include a heater in the form of a susceptor element extending 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 within the susceptor. Here, specific embodiments will be discussed in detail and are shown only by way of illustration in the following figures.

Brief Description of the Drawings

[0045]

Figure 1a

Figure 1b

Figure 2a

Figure 2b

Figure 3a

Figure 3b

Figure 3c

DETAILED DESCRIPTION OF THE INVENTION

[0046] Figure 1a is a schematic view of the heating chamber 10 of the 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 side wall 11 extending between the opening 13 and the base 15. The side wall 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. The recess 17 is defined by the inner surfaces of the base 15 and the side wall 11. The heating chamber 10 is configured to receive the aerosol-forming substrate into the recess 17 through the opening 13 of the first end 12.

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

[0048] An aerosol-forming substrate, such as a tobacco rod (not shown), is generally provided as part of an aerosol-generating article having an aerosol-forming substrate at its distal end and a filter at its proximal end. In use, the aerosol-forming substrate is inserted into 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 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 vapour from the substrate. When the user sucks on the mouthpiece of the article, air is drawn into the aerosol-generating article and the volatile substances condense to form an inhalable aerosol. This aerosol is trapped in the air drawn through the aerosol-generating article and enters the user's mouth through the mouthpiece of the aerosol-generating article.

[0049] During insertion of the aerosol-forming substrate into and removal of the substrate from the recess 17 of the heating chamber 10, a free substrate may be released into the chamber 17 and form unwanted debris 22 at the base 15. Residue (not shown) from the substrate may also deposit on the surface 18a of the heater 18. In FIGS. 1a and 1b, the debris 22 is shown accumulating within the heating chamber 10 at the intersection 25 between the inner surface of the base 15 and the inner surface of the side wall 11. The debris 22 is also shown accumulating at the intersection 27 between the inner surface of the base 15 and the surface 18a of the heater 18.

[0050] Tools such as brushes can be provided to clean debris 22 from the heating chamber 10 and residues from the heater 18. In FIG. 1b, a cleaning brush 28 within the heating chamber 10 is shown. The head of the brush 28 has a circular major axis cross-section. Since the heating chamber has a substantially rectangular cross-section at the second end 14, the brush bristles (not shown) of the brush 28 do not reach the corners or intersections 25, 27 of the heating chamber 10. The brush bristles of the brush 28 can be deformable to allow some of the brush bristles to reach the intersections 25, 27 of the heating chamber 10. However, deforming the brush bristles of the brush 28 to reach the intersections 25, 27 can undesirably increase the effort required of the user to clean the heating chamber 10, and can reduce the efficiency of the brush by making the brush more vulnerable to damage or by requiring the brush 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 the same side wall 31 as the side wall 11, the same first end 32 as the first end 12, and the same heater 38 as the heater 18. However, the heating chamber 30 has a base 35 at its second end 34, which is contoured around its perimeter to form a chamfer 35a around the outer end of the base 35 between the inner surface of the base 35 and the side wall 31. The chamfer 35a extends between the inner surface of the base 35 and the inner surface of the side wall 31 and is a substantially straight edge that effectively fills 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 the chamfer 35a abuts the inner surface of the side wall 31 at an angle of about 135° around the entire perimeter of the side wall 31. The base 35 is further contoured in a central region to create an internal chamfer 35b between the inner surface of the base 35 and the surface 38a of the heater 38. The internal chamfer 35b extends between the inner surface of the base 35 and the heater blade surface 38a and effectively fills the intersection between the inner surface of the base 35 and the heater surface 38a. The internal chamfer 35b extends upwardly at an angle of about 135° from the general plane of the base, and the inner end of the internal chamfer 35b abuts the heater surface 38a at an angle of about 135° around the entire perimeter of the lower portion of the heater.

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

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

[0054] Alternative embodiments are shown in FIGS. 3a, 3b, and 3c, where the base 55 is removable from the heating chamber 50. The heating chamber 50 of this embodiment has a closed second end 54 defined by the end portion 54a. FIG. 3a shows the removable base 55 positioned within the heating chamber at the closed second end (side walls removed for illustration of 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 the central slot 55c forming an inner fillet end 55b. In this embodiment, the base 55 includes fillets rather than chamfers in the outer perimeter and central regions. The fillets 55a, 55b provide curved ends at the intersections between the base 55 and the inner surface of the side wall (not shown) and the inner surfaces of the base 55 and the heater 58.

[0055] The slot 55c is arranged or dimensioned to receive the elongated, planar heating blade 58 such that the inner end of the inner fillet 55b abuts the lower surface 58a of the heating element 58. The base 55 includes a circular raised lip 55d that projects downwardly from the lower surface of the base 55 and engages the end 54a of the heating chamber 50 to space the lower surface of the base 55 from the end 54a. Of course, in other embodiments, the circular lip can be replaced with a plurality of leg elements, such as three or four leg elements evenly spaced around the base.

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

[0057] The removable base 55 is inserted into the heating chamber 50 through an open end (not shown) of the heating chamber 50. The heater 58 is received within the slot 55c and the base 55 is lowered into the recess of the heating chamber 50 until the base 55 reaches its fixed position at the closed end 54, and the raised lip 55d abuts against the end 54a of the heating chamber 50. When the base 55 is thus 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 means of the removal notch 55e around the base 55. The tool may either hook under the base 55 or attach to the base 55 at the notch 55e, and the user can pull the tool and the base 55 out of the heating chamber 50. The base 55 may be cleaned and replaced within the heating chamber 50 or, as described above, discarded and a new base 55 inserted into the heating chamber 50.

[0058] Of course, both integral and removable bases may have chamfered or filleted intersections. In some embodiments, the base may include a chamfered intersection at one of the outer and inner intersections and a fillet intersection at the other of the outer and inner intersections.

Claims

1. An aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol, comprising a heating chamber for heating the aerosol-forming substrate, the heating chamber including a first end having an opening, a second end having a base, and a side wall extending between the opening and the base, a recess being defined by the base and the inner surface of the side wall, the device further comprising a heating assembly and a power source, the heating assembly comprising a heater extending into the heating chamber through an inner portion of the base, the connection between the inner portion of the base and the heater being contoured to provide a substantially straight or curved transition region, an aerosol generating device.

2. The aerosol generating device according to claim 1, wherein the side wall extends substantially in a direction perpendicular to the base.

3. The aerosol generating device according to claim 1 or 2, wherein the connection between the inner surfaces of the base and the side wall is contoured to provide a substantially straight or curved transition region extending substantially around the periphery of the base.

4. The aerosol generating device according to claim 1, wherein the heater is a resistive heater or an inductive heater.

5. The aerosol generating device according to claim 1, wherein the heater is a susceptor and the heating assembly further includes an inductor coil.

6. The aerosol generating device according to any one of claims 1 to 5, wherein the heater extends substantially into the heating chamber in a direction parallel to the side wall.

7. The aerosol generating device according to claim 1, wherein the heating assembly comprises an external heater.

8. The aerosol generating device according to any one of claims 1 to 7, wherein the opening of the heating chamber is defined by the side wall and is configured to face the base.

9. The aerosol generating device according to any one of claims 1 to 8, wherein the base is integrally formed with the side wall of the heating chamber.

10. The aerosol generating device according to any one of claims 1 to 8, wherein the base is removable from the device.

11. The aerosol generating device according to claim 10, wherein the base is removable and insertable through the opening at the first end of the heating chamber.

12. The aerosol generating device according to claim 10, wherein the base is removable and insertable through the opening in the side wall of the heating chamber adjacent to the second end of the heating chamber.

13. The aerosol generating device according to any one of claims 10 to 12, wherein the base has engaging means for engaging with a removal tool.

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