FIELD OF THE INVENTION

The present invention relates to a consumable cartridge for an aerosol generation device and a method of manufacture thereof. The disclosure is particularly applicable to a portable aerosol generation device.

BACKGROUND

Consumable cartridges, also known as pods, are used in aerosol generation devices such as electronic cigarettes and vaping devices to provide an aerosol generating medium or liquid that is heated to generate an aerosol or vapour for inhalation by a user.

After a period of use, the consumable cartridge becomes depleted and is removed and discarded by the user. It has been found that consumable cartridges in the art are difficult to recycle or reuse, and are often thrown away as non-recyclable waste.

An object of the invention is to improve the manufacturability and recyclability of consumable cartridges for aerosol generating devices.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a consumable cartridge for an aerosol generation device, comprising: an aluminium body having a nozzle arranged along a longitudinal axis inside of the aluminium body, the nozzle configured to deliver generated aerosol to a user; a liquid reservoir comprising an aerosol generating liquid, the liquid reservoir positioned radially outwardly with respect to the nozzle within the aluminium body; a wick assembly comprising a wick and an opening, the wick configured to draw the aerosol generating liquid from the liquid reservoir through the opening; and an aluminium end cover connected to the aluminium body so as to encase the liquid reservoir and the wick assembly.

In this way the use of aluminium in consumable cartridges can be increased, which consequently allows for improved recyclability and reduces the impact on the environment. Due to the complexity of designs and the relatively small sizes of consumable cartridges, many of the parts in known cartridges typically use plastic materials which are easily formed to shape but can be more difficult to recycle or reuse. Advantageously, the outer casing of the present cartridges (that is the body and the end cover) is made of aluminium and would readily prompt a consumer to recycle a spent cartridge after use. The aluminium body may be cup-shaped.

The wick may be a porous ceramic wick which is configured to store the aerosol generating liquid within the wick until the aerosol generating liquid is heated to a temperature that causes it to aerosolize, i.e. generate an aerosol. As will be understood, the porosity of the wick may be defined with respect to the viscosity of the aerosol generating liquid.

Preferably, the wick assembly comprises a seal arranged between the wick assembly and the liquid reservoir. In this way, the seal prevents the aerosol generating liquid from leaking out of the reservoir outside of the opening of the wicking assembly. In other words the seal ensures that aerosol generating liquid only passes from the reservoir to the wick through the opening in the wick assembly.

Preferably, the wick assembly comprises an airflow path from outside of the consumable cartridge to the nozzle. In this way, air is directed to flow through the wick assembly and to carry generated aerosol from the wick to the nozzle, where the generated aerosol can be inhaled by the user. The airflow path may comprise an airflow channel that is formed in the wick assembly. Alternatively the airflow path may comprise an inlet hole for outside air to reach the wick and an outlet hole for the air to continue flowing from the wick to the nozzle. The airflow path may be T-shaped, where two air channels in the wick assembly direct air in a horizontal direction from outside the consumable cartridge to the wick in a central area in the wick assembly, and where the air along with aerosol generated in the wick is directed in a vertical direction up the nozzle in the aluminium body. As will be apparent to the skilled person, the wick assembly may comprise more than two air channels.

Preferably, the consumable cartridge comprises one or more air inlet holes in the aluminium body and/or the aluminium end cover. The air inlet holes allow air from outside the consumable cartridge to be drawn into the cartridge and the wick assembly. The air inlet holes may be provided in the aluminium body or the aluminium end cover, or both, according to design requirements.

Preferably, the wick assembly comprises one or more liquid traps along the airflow path. In this way, any undesirable moisture or condensation that forms in the airflow path, which can obstruct or impede airflow, can be directed or drawn out of the airflow path. The moisture may due to the humidity of the outside air or from the aerosol generating liquid in the wick. As an example, the liquid trap may comprise one or more side channels in the airflow path that draw away any moisture in the airflow path by capillary action. The side channel(s) may lead the moisture to a foam or sponge material that absorbs and retains the moisture.

Preferably, the wick assembly further comprises a condensation trap arranged between the wick and the nozzle. In this way, any condensed aerosol that has not been directed up the nozzle (and to a user) can be returned to the wick for reabsorption and re-aerosolization, thereby reducing wastage of unused aerosol generating liquid. This can also help to reduce contact between a user and any liquid aerosol forming substrate.

Preferably, the wick assembly further comprises a thermal interface layer arranged between the wick and one or more holes in the aluminium end cover. In this way, heat transfer from a heater in the aerosol generation device to the wick can be improved. The one or more holes in the aluminium end cover ensure that the heat from the heater is not conducted across the aluminium material away from the wick. A thermally insulating seal may be provided between the thermal interface layer and the aluminium end cover to minimise any undesirable thermal conduction into the end cover. The thermal interface layer may comprise a thermal interface material or membrane comprising stainless steel, titanium foil, or polyetheretherketone (PEEK). The thermal interface layer may have a thickness of 15 to 25 microns.

Preferably, the wick assembly is arranged radially inwardly with respect to the aluminium end cover. The aluminium end cover may be cup-shaped to hold the wick assembly within. The aluminium end cover may be punched and deep drawn to shape. Alternatively, the aluminium end cover may be pressured, or cold-forged depending on the speed and cost of the operation and manufacturer capability. A nozzle may be punched or otherwise formed in the aluminium end cover and cupshape of the outer wall may be drawn or otherwise shaped around the nozzle. The opening of the nozzle in the end cover may be plugged to prevent airflow through the opening, according to airflow design requirements of the cartridge. For example, the nozzle and opening in the end cover may be used as the socket connection that is plugged by a plug provided in the aerosol generation device such that the plug-socket connection fixes or attaches the consumable cartridge to the device.

Holding the wick assembly in a cup-shaped aluminium end cover allows the outer wall of the aluminium end cover to provide a structural support to the wick assembly. The cup shape of the aluminium end cover and wick assembly provided within also ensures that the aerosol generating liquid in the cartridge is effectively used since the wick can be arranged at the lowest point of the cartridge. As indicated above, one or more holes may be drilled or otherwise provided in a bottom surface of the cartridge (adjacent to the heater or heater element of the aerosol generation device), such that the thermal interface layer acts as the interfacing layer between wick assembly and a heater. Preferably, the wick comprises one or more air channels. The air channels may be provided toward the lower end of the wick, adjacent to the thermal interface layer. In this way, the air channels allow improved airflow through the wick, which in turn improves the distribution of heat and vaporisation of the aerosol generating liquid into generated aerosol. The air channels may also allow enhanced delivery to the nozzle of the cartridge for inhalation by the user, and thus minimise condensation of generated aerosol. As such, the air channels can ensure optimal vape generation and prevent vape accumulation below the wick.

Preferably, a cross-sectional area of the nozzle increases along the longitudinal axis in a direction to the user. In this way, the shape of the nozzle is configured to deliver an optimum airflow and draw resistance for a user. The vape of air and generated aerosol is thus delivered to the user as a homogeneous, laminar vape outflow. The airflow path widens across its cross-sectional profile which slows down the flow of air and generated aerosol in the nozzle, thereby cooling the vape before inhalation.

Preferably, the aluminium body or aluminium end cover is shaped to fasten into the aerosol generation device by a push-fit mechanism. In this way, the consumable cartridge can be readily attached to the aerosol generation device. The aluminium body and/or aluminium end cover may also comprise punched notches, or hard stops, to allow a press-fit or push-fit connection of the wick assembly into the body and/or end cover. This advantageously allows the assembly of the cartridge to be faster and more efficient.

Preferably, the aluminium end cover is connected to the aluminium body by a seamed edge connection. In this way a leak-proof connection is provided between the aluminium body and the aluminium end cover so that the aerosol generating liquid in the liquid reservoir cannot leak out of the cartridge in liquid form. A seamed-edge connection can also advantageously speed up the manufacturing process of a consumable cartridge. The connection may further comprise sealant, such as silicone, on the respective seamed edges of the end cover and body. Alternatively, the aluminium end cover may be connected to the aluminium body by a press-fit connection. Sealant may also be used to ensure a leak-proof connection.

Preferably, an inner surface of the aluminium body is coated. In this way, the surface of the liquid reservoir in contact with the aerosol generating liquid is coated, which prevents any metallic contamination of the aerosol generating liquid (which may cause an undesirable metallic taste to the vape). A ceramic or polymer coating may be applied to the inner surface of the aluminium body, preferably after the body is formed in the aluminium, and before filling the reservoir or further assembly of the cartridge. For example, the coating may be a Teflon coating. The inner surface of the aluminium end cover may also be coated.

Preferably, each of the aluminium body and the aluminium end cover is made of a single piece of aluminium. In this way, the consumable cartridge can be efficiently manufactured and assembled. In addition the use of two single pieces of aluminium to form a cartridge can effectively reduce or eliminate any joints that may potentially be a source of liquid leakage.

In another aspect of the invention there is provided a method of manufacturing a consumable cartridge according to the first aspect of the invention, the method comprising the steps of: providing a first aluminium disc; punching through the first aluminium disc to form a nozzle; drawing the first aluminium disc around the nozzle to form a body around the nozzle, defining a liquid reservoir around the nozzle in the body; filling the liquid reservoir with an aerosol generating liquid; enclosing the liquid reservoir with a wick assembly comprising a wick and an opening; and connecting a second aluminium disc to the body of the first aluminium disc so as to encase the liquid reservoir and the wick assembly.

In this way, a faster and more efficient manufacturing process is provided. Multiple steps of punching and drawing may be applied to form the aluminium body, and optionally the aluminium end cover. A punch tool may be used to form the nozzle in an aluminium disc and another punch tool may be used to form the outer body shape. The nozzle may be punched several times or drawn to extend the length of the nozzle such that the outer surface of the nozzle and the inner surface of the body together form the liquid reservoir.

The aluminium consumable cartridge of the present disclosure considers a production amount that would be envisaged for consumable cartridges for electronic cigarettes (a mass production of more than 10 million pieces per year), and realises that standard milling processes (such as CNC, machining or turning) cannot be realistically applied due to the high costs and long production time of such processes.

The manufacturing method of the present invention therefore uses deep-drawing techniques for aluminium on all outer surfaces. It should be appreciated that, due to the manufacturing limitations of the deep drawing process, it may be possible that relatively large draft angles would need to be applied on the vertical faces. Cold forging or pressing may also be considered as alternative manufacturing methods.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention are now described, by way of example, with reference to the drawings, in which:

Figures 1 A and 1 B are perspective views of a consumable cartridge according to a first embodiment of the invention;

Figure 2 is a cross-sectional view of the consumable cartridge according to the first embodiment of the invention;

Figures 3A and 3B are schematic views of a wick assembly according to the first embodiment of the invention;

Figure 4 is a schematic view of a wick according to the first embodiment of the invention; Figure 5 is another cross-sectional view of an aluminium consumable cartridge according to the first embodiment of the invention;

Figures 6A and 6B are perspective views of a consumable cartridge according to a second embodiment of the invention;

Figures 6C and 6D are cross-sectional views of connection joints according to the second embodiment of the invention;

Figure 7 is a cross-sectional view of the consumable cartridge according to the second embodiment of the invention;

Figure 8 is another cross-sectional view of an aluminium consumable cartridge according to the second embodiment of the invention;

Figure 9 is an exploded cross-sectional view of the consumable cartridge according to the second embodiment of the invention; and

Figure 10 is a schematic view of forming an aluminium body according to the invention.

DETAILED DESCRIPTION

As described herein, a vapour is generally understood to refer to a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapour’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

Figures 1A and 1 B illustrate outer views of a consumable cartridge 2 or pod according to a first embodiment of the invention. The consumable cartridge 2 has an aluminium outer shell which is made of an upper body 4, which is cup-shaped, and a lower end cover 6. The upper body 4 has an air outlet 8 from which generated aerosol can be delivered and inhaled by a user. The air outlet 8 is the open end of a nozzle provided inside of the upper cup-shaped body 4.

The end cover 6 has a hole 10, which may be drilled, water jet cut or otherwise formed in the end cover 6, which reveals a thermal interface layer inside of the pod 2 against which a heating element 12 of an aerosol generation device (not shown) can press against and heat. As will be explained below, the thermal interface layer is part of a wick assembly in the consumable cartridge 2 in which a wick holding an aerosol generating liquid, or e-liquid, is arranged.

The consumable cartridge 2 also has air inlet holes 14 that are drilled into the side of the upper body 4, and notches 16 in the body 4 that are used as hard stops for the wick assembly during the manufacturing process of the pod.

Figure 2 shows a cross-sectional view of the consumable cartridge 2 having the upper cup-shaped body part 4 and the lower end cover part 6. The upper body 4 is formed from a single piece of aluminium that is shaped to form a central nozzle 20 and an outer shell 22, and the upper body 4 has a seamed edge that is interconnected with a respective seamed edge of the end cover 6 to form a seamed-edge connection 24. The wall of the central nozzle 20 is tapered such that the cross-sectional profile of the nozzle 20 increases from an aerosolreceiving end 26 of the nozzle 20 to the air outlet 8 (i.e. the open end of the nozzle).

The consumable cartridge 2 includes a wick assembly 28 arranged inside the upper body 4 and end cover 6. The outer surface of the central nozzle 20, the inner surface of the outer shell 22 (which may be a coated surface) and the top surface of the wick assembly 28 together form a liquid reservoir 30 in which an aerosol generating liquid can be stored inside the consumable cartridge 2. The reservoir 30 is able to accommodate up to 2 millilitres (ml) of liquid.

The wick assembly 28 is a support structure that may be made of two plastic parts for ease of construction, and contains within a chamber 32 of the assembly and a porous ceramic wick 34 that draws the aerosol generating liquid out of the liquid reservoir 30 through at least one opening (not shown) in the wick assembly 28. It should be appreciated that, when constructed, the aerosol generating liquid can only flow out of the liquid reservoir 30 through the opening in the wick assembly 28 into the wick 34.

The wick assembly 28 further includes air channels 36 which are aligned with the air inlet holes 14 in the upper body 4 to provide airflow paths from outside of the consumable cartridge 2 to the wick 34 in the chamber 32 of the wick assembly 28. The airflow paths along the air channels 36 direct air in a horizontal direction, and combine in the chamber 32 such that air is further directed up the central nozzle 20 in a single airflow path having a vertical direction. The combined airflow path through the air channels 36 and the central nozzle 20 is thus T-shaped.

The air channels 36 each further comprise a side channel 38 that acts as a leakage path for any moisture that may collect or condense within a respective air channel 36. The side channels 38 can draw the moisture away from airflow path of the air channels 36 into an absorption foam 40 provided beneath the wick assembly 28, between the wick assembly 28 and the end cover 6. Alternatively, the absorption foam 40 can be arranged as part of the wick assembly 28, as will be obvious to the skilled person.

The chamber 32 of the wick assembly 28 is arranged over the hole 10 in the end cover 6, and the wick assembly 28 includes a layer of thermal interface material 42 that covers the hole 10. As explained above in reference to Figure 1 B, the outer surface of the thermal interface material 42 is in contact with a heating element of an aerosol generation device in use and transmits heat from the heating element to the wick 34 that sits on the inner surface of the thermal interface material 42 in the chamber 32. A thermally insulating seal 44 is provided at the edge of the thermal interface material layer 42 such that the insulation seal 44 prevents heat from being conducted into the aluminium end cover 6 or the rest of the wick assembly 28. In other words, the thermal insulation seal 44 ensures that heat received from the heating element / heater is optimally transmitted through the thermal interface layer 42 to the wick 34, and heat loss to the surrounding material (of the end cover 6 or the wick assembly 28) is minimised.

The wick assembly 28 is attached to the receiving end 26 of the nozzle 20 such that aerosol generated from the liquid in the wick 34 (on heating) can travel up through to nozzle 20 to a user. The wick assembly 28 includes a seal 46 provided at the attachment between the assembly 28 and the nozzle 20 to prevent any leakage from the liquid reservoir 30 into the chamber 32 or nozzle 20. The seal 46 may be made of silicone or another suitable material in the art, such as rubber.

The wick assembly 28 further includes a core seal 48 or a chamber seal which is used to hold the wick 34 in place inside the chamber 32. The core seal 48 is heat resistant to prevent any deformation or heat transmission from the wick 34 to the remainder of the wick assembly 28. In addition the core seal 48 is shaped to include a condensation trap 50 such that any aerosol that did not travel up the nozzle 20 or was not inhaled by the user is able to condense into droplets in the condensation trap 50 and return to the wick 34 for absorption and be re-heated for aerosolization. The core seal 48 may also be made of silicone.

Figures 3A and 3B show additional views of a constructed and exploded wick assembly 28. As can be seen in Figure 3A, the air channels 36 are moulded into the plastic material of the wick assembly 28 between an air inlet of the wick assembly (which is aligned with a corresponding air inlet hole 14 of the upper body 4) and the central chamber 32. The top surface of the wick assembly 28 is used to enclose the liquid reservoir 30 between the nozzle 20 and the inner surface of the outer shell of the upper body 4, and aerosol generating liquid in the liquid reservoir 30 can enter the chamber 32 through the opening 52 in the wick assembly 28. The top channel 54 of the wick assembly 28 attaches to the receiving end 26 of the nozzle 20 and the seal 46 arranged around the inner surface of the top channel 54 interfaces with the outer surface of the receiving end 26 of the nozzle 20 to prevent any leakage.

The exploded view of the wick assembly 28 in Figure 3B shows how the wick assembly may be constructed. Figure 3B further illustrates the core seal 48 that fixes the position of the wick 34 inside the chamber 32 of the wick assembly 28 on top of the thermal interface layer 42. The outer edge of the thermal interface layer 42 is encased in a thermal insulation seal 44 to control the direction of heat transmission from the heater to the wick 34. The absorption foam layer 40 is provided below the main body of the wick assembly 28 such that the side channels 38 can direct any moisture in the air channels 36 to the foam layer 40.

Figure 4 shows the wick 34 of the first embodiment of the invention, where the wick 34 includes a number of air channels 56 at the lower surface of the wick 34 where the wick 34 interfaces with the thermal interface layer 42. The air channels 56 in the wick allow air from the air channels 36 of the wick assembly 28 to readily flow into the wick 34 for improved aerosol delivery. The reduced surface area of the wick 34 against the thermal interface layer 42 effectively reduces the volume of the wick 34 (and aerosol generating liquid stored within) nearer the heater, which in turn reduces the heat-up time of the wick 34 and the generation of aerosol.

Figure 5 illustrates a cross-sectional view of the consumable cartridge 2 without the wick assembly 28, and only shows the upper body 4 connected to the end cover 6. The upper body 4 has notches 16, which may be formed by a punching process, below the receiving end 26 of the nozzle 20. The notches 16 act as a stop or a push-fit mechanism for the main body of the wick assembly 28 during construction. The outer wall of the wick assembly 28 may be configured accordingly to match the shape of the notches 16. The seamed edge connection 24 between the upper body 4 and the end cover 6 is filled with a sealant to further enhance the leak-proof quality of the connection 24.

Figures 6A and 6B illustrate outer view of another consumable cartridge 102 or pod according to a second embodiment of the invention. The consumable cartridge has an aluminium outer shell that includes an upper body 104 and a lower end cover 106 or end part. The upper body 104 and the end cover 106 are both cup-shaped. The upper body 104 has an air outlet 108, which is the opening at the end of a nozzle provided inside of the upper body 104. The end cover 106 has two holes 110 cut out in its bottom surface, which reveal a thermal interface layer in the consumable cartridge 102. The thermal interface layer is configured to come into contact with a heater 112 of an aerosol generation device and conduct heat into the consumable cartridge 102. As will be explained below, the thermal interface layer is part of a wick assembly in the consumable cartridge 102 in which a wick storing an aerosol generating liquid is provided.

The upper body 104 and the end cover 106 are connected together at their respective edges at a connection joint 114. The connection joint 114 may be filled with a sealant to ensure a leak-proof connection.

Figure 6C shows a cross-sectional view of a first example, where the connection joint 114 is a seamed edge connection 114A, where the respective edges of both the upper body 104 and the end cover 106 are seamed. Figure 6D show a cross- sectional view of a second example, where the respective edges and the aluminium metal toward the edges of the upper body 104 and the end cover 106 are pressed or otherwise shaped respectively to provide a press-fit connection 114B between the upper body 104 and end cover 106.

The consumable cartridge 102 also has air inlet holes 116 that are drilled or formed in the side of the end cover 106. The size of the air inlet holes 116 define a draw resistance of the cartridge 102.

Figure 7 shows a cross-sectional view of the aluminium outer shell. The upper body 104 has a central nozzle 118 and an outer wall 120 formed radially around the outer surface of the central nozzle 118. The central nozzle 118 has an aerosol receiving end 122 and an opening which is the air outlet 108 of the cartridge 102. The wall of the central nozzle 118 is tapered, where the cross-sectional area of the nozzle 118 increases from the receiving end 122 to the air outlet 108.

The outer wall 120 has a thickness of around 0.2 millimetres. The upper body 104 is made from a single piece or disc of aluminium that is punched and drawn in a multistage process, as will be described further below. The receiving end 122 of the central nozzle 118 and the edge of the outer wall 120 is shaped to a press-fit edge 124 for connection with the end cover 106.

The end cover 106 also has a nozzle 126, which may be plugged and/or used for another purpose such as a push-fit or alignment connection with an aerosol generation device. The end cover 106 has an outer wall 128 radially around the nozzle 126, and the air inlet holes 116 described above are drilled into the end cover outer wall 128. The end cover nozzle 126 is also tapered such that the cross-sectional area of the nozzle 126 decreases from the bottom surface of the end cover 106 to the top end 130 of the end cover nozzle 126, which connects to the receiving end 122 of the central nozzle 118 of the upper body 104. The smaller cross-sectional area where the central nozzle 118 connects with the end cover nozzle 126 allows for a higher speed of delivery of aerosol into the central nozzle 118, and the widening cross-sectional area of the central nozzle 118 retards the speed of delivery of aerosol as it travels through the central nozzle 118 to a user, which allows the aerosol to cool.

Similar to the upper body 104, the end cover 106 in the second embodiment is also made from a single piece or disc of aluminium that is punched and drawn in a multistage process. The top end 130 of the end cover nozzle 126 and the edge of the outer wall 128 is shaped to a press-fit edge 132 for connection with the upper body 104.

Aerosol delivery holes 134 are provided in the end cover nozzle 126 so as to provide an airflow path from the air inlet holes 116 to the aerosol delivery holes 134. It should therefore be understood that, in use, outside air enters the cartridge 102 through the air inlet holes 116, picks up generated aerosol as it passes through the wick, and the air and aerosol is delivered through the aerosol delivery holes 134 to the receiving end 122 of the central nozzle 118 of the upper body 104 for further delivery to the air outlet 108 and user inhalation.

The bottom surface of the end cover 106 has holes 110 that are cut out in a shape to correspond with the interfacing heater of an aerosol generation device. This is to allow the heater or heating element to pass through the bottom surface of the end cover 106 and press against the thermal interface layer of the wick assembly of the cartridge 102.

Figures 8 and 9 shows a cross-sectional views of the consumable cartridge 102 having the upper body 104 and the lower end cover 106 connected using a push- fit or press-fit connection. The press-fit edge 124 of the upper body 104 interlocks with the press-fit edge 132 of the end cover 106, and the top end 130 of the end cover nozzle 126 is pushed into and fitted within the receiving end 122 of the upper body central nozzle 118. The receiving end 122 of the central nozzle 118 also flares outwardly, which along with the press-fit edge 124 of the upper body 104 act as a stop for a wick assembly 136 of the consumable cartridge 102.

The wick assembly 136 is positioned in the end cover 106 in the space radially around the end cover nozzle 126, between the outer surface of the end cover nozzle 126 and the inner surface of the outer wall 128 of the end cover 106. The outer surface of the central nozzle 118, the inner surface of the outer wall 120 of the upper body 104 and the top surface of the wick assembly 136 together form a liquid reservoir 138 in which an aerosol generating liquid can be stored inside the consumable cartridge 102. The internal surfaces of the upper body 104 and end cover 106 are coated with a ceramic or polymer coating.

As seen more clearly in the exploded view of Figure 9, the wick assembly 136 includes a porous ceramic wick 140 that is surrounded by an upper seal cap 142 over its top surface, a membrane 144 around its side walls and a thermal interface layer 146 on its lower surface. The upper seal cap 142 is made of silicone and has openings 148 to allow aerosol generating liquid to flow out of the liquid reservoir 138 into the wick 140. It should be appreciated that, when constructed, the aerosol generating liquid can only flow out of the liquid reservoir 138 through the openings 148 in the upper seal cap 142 into the wick 140. The upper seal cap 142 extends over the top surface of the wick 140 to the upper end of the sides of the wick 140 (which include the surfaces of the wick 140 adjacent to both the end cover outer wall 128 and the end cover nozzle 126) to ensure any leakage of aerosol generating liquid away from the openings 148 is prevented. The interfacing surfaces of the upper seal cap 142 and the wick 140 along the sides of the wick 140 are ridged respectively to provide a secure fit of the upper seal cap 142 over the wick 140.

The membrane 144 of the wick assembly 136 provided around the side surfaces of the wick 140 (which include the surfaces of the wick 140 adjacent to both the end cover outer wall 128 and the end cover nozzle 126) is a polymer membrane such as polytetrafluoroethylene (Teflon). The membrane 144 is air-permeable, and optionally may further include additional holes to improve the distribution air through the wick 140. The wick 140 and the membrane 144 is also shaped to allow a gap between the membrane and the outer wall 128 of the end cover 106 and/or the end cover nozzle 126 for improved airflow through the wick 140.

The thermal interface layer 146 is an impermeable layer that covers the bottom surface of the wick 140 to prevent liquid from leaking out of the wick 140 through the holes 110 in the end cover 106. The thermal interface layer 146 extends across the bottom surface of the wick 140 to the lower end of the sides of the wick 140 (which include the surfaces of the wick 140 adjacent to both the end cover outer wall 128 and the end cover nozzle 126) to prevent leakage.

The outer surface (i.e. the lower surface) of the thermal interface layer 146 is in contact with a heating element of an aerosol generation device in use and transmits heat from the heating element to the wick 140 that sits on the inner surface of the thermal interface layer 146 in the wick assembly 136. A thermally insulating seal (not shown), such as a silicone sealant, is used to glue the thermal interface layer 146 to the bottom surface of the end cover 106, which prevents or minimises heat from being conducted into the aluminium end cover 106.

Similar to the first embodiment, the wick 140 may include a number of air channels (not shown) at the lower surface of the wick 140 where the wick 140 interfaces with the thermal interface layer 146 to improve air and heat distribution through the wick 140. A plug 150 is optionally provided to block the opening of the end cover nozzle 126 at its bottom surface, or alternatively the plug 150 may be part of the aerosol generation device in which the consumable cartridge 102 is inserted. Figure 10 illustrates in schematic form a process 200 to form an aluminium body, such as the upper bodies 4, 104 of the consumable cartridges of the first and second embodiments and the end cover 106 of the second embodiment.

At step 202, an aluminium disc 250 is cut out from a sheet roll of aluminium metal. The size of the disc 250 is equal to the surface area of the upper part of a consumable cartridge 2, 102. The disc 250 may be cut out from the roll of aluminium using a stamp process.

At step 204 a punch tool 252 is used to strike the centre of the disc 250 to form a nozzle 254 in the disc 250. Multiple punches may be required to draw the nozzle 254 to a desired length shown at step 206. Lubrication, such as oil or grease, may be applied to prevent any tearing of the disc 250. In order to form a tapered wall, several punch tools of decreasing diameter may be used as the nozzle 254 is drawn out of the disc 250. It will be understood that the disc 250 is placed on a suitable holder during step 204 to prevent the material around the nozzle 254 from deforming during the punching process.

At step 208, a different punch tool 256 having a socket-style or tube-shaped form is used to form the outer wall 258 of the body. As above, multiple punches may be required to draw the disc 250 around the nozzle 254 to a desired length, and multiple punch tools of different internal diameters may be used, as shown at step 210, to draw out the outer wall 258 and ensure a smooth outer profile. At step 212 the outer wall 258 is drawn to a length greater than the length of the nozzle 254 to form the body.