Heating apparatus for aerosol-generating device

Abstract

A heating apparatus for an aerosol-generating device is disclosed, the heating apparatus (10) comprising: a heat insulator comprising an inner wall (16) defining a heating zone and comprising an opening (20) through which an aerosol-forming substance can be received in the heating zone, and an outer wall (14) positioned radially outward with respect to the inner wall; the insulation further comprises a weld bridge (24) connecting the inner wall and the outer wall, where the weld bridge comprises a groove (32); and a heating element disposed on the inner wall and configured to provide heat to the received aerosol-forming substance.

Description

TECHNICAL FIELD

[0001] The present invention relates to a heating apparatus for an aerosol generating device and an aerosol generating device comprising the heating apparatus. The present disclosure is particularly applicable to portable aerosol generating devices, which can be self-contained. In particular, the present invention relates to an aerosol generating device having a heater arranged within a vacuum or thermally insulated chamber. BACKGROUND

[0002] The production of electronic cigarettes that heat but do not burn solid or semi-solid aerosol-forming substrates, typically referred to as consumables, including tobacco, is a field of development of interest. These aerosol generating devices typically receive a consumable tobacco rod in a heating chamber. The rod is heated to release an aerosol that can be inhaled by a user. A common problem with these devices is that the heater that supplies heat to the heating chamber also undesirably heats the remainder of the device. This can be particularly disadvantageous in compact devices, as the temperature of the outer surface of the device that is held by the user can be unacceptably high.

[0003] To mitigate these effects, some aerosol generating devices are provided with vacuum chambers that can space the heater from the outer surface and provide thermal isolation between the heating chamber and the outer surface that is held by the user. Within such aerosol generating devices, it is also desirable to improve the efficiency of the heating operation so that the battery life of the device can be extended. To this end, vacuum insulations have been employed within aerosol generating devices in order to thermally insulate the cavity in which the aerosol substrate is heated, thereby limiting the heat loss to the external environment.

[0004] It is an object of the present invention to further improve the heating efficiency and reduce the undesired heat loss. SUMMARY

[0005] According to an aspect of the present invention, there is provided a heating apparatus for an aerosol generating device, the heating apparatus comprising: an insulation body comprising an inner wall and an outer wall, the inner wall defining a heating zone and comprising an opening through which an aerosol-forming substance can be received in the heating zone, the outer wall being positioned radially outwardly relative to the inner wall; the insulation body further comprising a welded bridge connecting the inner wall and the outer wall, wherein the welded bridge comprises a recess; and a heating element arranged on the inner wall and configured to provide heat to the received aerosol-forming substance.

[0006] By reducing the amount of weld material connecting the inner wall and the outer wall, the heating zone is better thermally insulated. As will be appreciated, heat generated from the heating element is transferred to the inner wall and the received aerosol-forming substance by thermal conduction. The heating zone can be considered as a cavity in which the aerosol-forming substance can be received and heated by the heating element. The generated heat is thermally insulated by the space between the outer wall and the inner wall, which can be a vacuum or filled with a thermally insulating material. However, heat can be conducted from the inner wall to the outer wall through the bridge connecting the two walls or the welded bridge. To minimise and limit the thermal conduction or heat loss from the inner wall / heating zone through the bridge, a groove is cut out of the welded bridge to reduce the material thickness of the bridge while maintaining the structural / physical integrity of the bridge (to enclose e.g. a vacuum).

[0007] In some embodiments, both the inner wall and the outer wall comprise a metallic material, and the first end of the outer wall can be laser welded to the bridge. In this way, both the inner wall and the outer wall can be made of a metallic material for ease of manufacture. The inner wall can comprise a metallic material to improve the thermal conduction from the heater to the aerosol-forming substance / consumable received in the heating zone. Preferably, the bridge is laser welded to the inner wall. In this way, the high precision of the laser welding technique ensures that a bond can be made between the inner wall, the bridge and the outer wall. Advantageously, laser welding ensures a particularly effective bond between the surfaces of the weld, which requires a low surface area for the bond. Other welding techniques such as resistance welding can also be employed.

[0008] The groove can be V-shaped or U-shaped or even any other shape depending on the manufacturing / design requirements. Preferably, the groove can be cut out of the welded bridge by grinding or machining or by another method as will be appreciated by the person skilled in the art. Importantly, the groove reduces the thickness of the welded bridge such that the section of the bridge where the thickness is reduced acts as a "thermal break" to significantly prevent unwanted heat loss (i.e. thermal conduction) from the heating zone. As such, the present invention improves the effectiveness of the heating apparatus by reducing the heat transfer from the inner wall out to the outer wall and to the outside of the aerosol generating device.

[0009] The welded bridge can be a loop, preferably wherein the loop is annular. In this way, the bridge acts as a spacer between the inner wall and the outer wall and can also enclose the thermally insulating space between the two walls. The annular loop ensures that the bridge encircles the inner wall and can join the inner wall completely to the outer wall.

[0010] Preferably, the welded bridge comprises a predetermined minimum thickness. It will be appreciated that the welded bridge must be sufficiently connected to the respective inner and outer walls (at each end of the bridge) that the surface area ensures that sufficient bonding is formed between the bridge and the walls. These surface areas are determined by the thickness of the bridging material (and the length of the bridge material along the respective inner and outer walls). However, the thickness of the bridge can be reduced away from the ends of the welded bridge (i.e. in the middle section of the bridge), wherein a recess can be cut into the middle section of the bridge. Thus, the minimum thickness can be the thickness of the remaining material of the middle section of the bridge in which the recess has been cut. For example, the minimum thickness of the welded bridge can be at the location where the apex of the recess is located in the bridge. The minimum thickness of this middle section of the bridge / recess section of the bridge can be predetermined so as to ensure that the welded bridge is able to maintain structural integrity on the bridge component and provide an effective insulating space between the inner and outer walls, particularly when the inner and outer walls and the welded bridge enclose a vacuum or contain an insulating material which, if not enclosed, can leak or spill out of the space.

[0011] Preferably, the welded bridge comprises a filler material. In this way, the thickness of the welded bridge can be more easily controlled. Suitable filler materials and rods will be apparent to those skilled in the art of welding thin walled joints. Alternatively, the bridge can be welded without a filler material by melting the inner and outer walls (i.e. base materials) together.

[0012] Preferably, the face of the outer wall is arranged at least a predetermined distance from the face of the inner wall. In this way, a sufficient length of the welded bridge can be provided to allow a recess to be cut into the bridge.

[0013] Preferably, a vacuum is enclosed between the inner and outer walls. Alternatively, the insulator can further comprise an insulating material located between the inner and outer walls. For example, the first insulator can comprise an aerogel material located between its inner and outer walls. Examples of insulating materials include, but are not limited to: air, aerogel material, powder or fibrous insulating material.

[0014] Preferably, the heating apparatus further comprises a heating cup comprising an inner wall and an end for limiting the insertion depth of a received aerosol-forming substance. In this way, the heating cup provides an end of the heating zone / cavity for the received aerosol-forming consumable to abut against. In this way, the heater can have a closed end such that there is a single opening for airflow and for insertion of an aerosol-forming consumable. Alternatively, the end can further comprise one or more apertures to enable airflow into the heating zone / cavity.

[0015] Preferably, the heating apparatus further comprises a heating sleeve, the heating sleeve comprising an inner wall. In these arrangements, a weld bridge can connect a first end of the inner wall with a first end of the outer wall, and a second weld bridge can be used to connect a second end of the inner wall with a second end of the outer wall. In this way, a weld bridge is provided at each end of the heating sleeve to limit the conduction of heat away from the inner wall / heating sleeve. The heating sleeve allows airflow to pass through the sleeve, such that the resulting aerosol can be carried by the airflow to the user upon inhalation.

[0016] Preferably, the heating element is disposed between the inner wall and the outer wall. The heating apparatus can further comprise an electrically insulating layer disposed between the heater and the inner wall. In this way, the safety of the device can be increased, as electrical conduction with other components of the heating apparatus or aerosol generating device can be avoided. The electrically insulating layer can be provided as a layer of material deposited on the inner wall. Alternatively, the layer can be provided as a partial or full coating on the heater.

[0017] Preferably, the heating element comprises a resistive track printed or coated or wound on the inner wall. In this way, the heating element can efficiently transfer heat to the aerosol generating substance received in the inner wall by thermal conduction. A printed or coated heating element can also ensure reliable electrical contact with the inner wall. Furthermore, manufacturing ease can be further improved. Alternatively, the heating element can comprise a separate heating track wound on the inner wall, such as a thin film heater. In other words, the heating element can comprise a thin film heater having an electrically conductive metal track interposed between insulating layers, such as polyimide films. Alternatively, the heating element can comprise an induction heater powered by a coil arranged in the thermal insulator.

[0018] Preferably, the heating apparatus further comprises one or more wires configured to connect the heating element to a power source, which can supply power to the heating element. The one or more wires can be positioned through one or more gaps in the outer wall / cup. The wires can have a small mass, which is advantageous for the carrying weight of the user and to reduce the thermal mass of the device.

[0019] This configuration can be simple to manufacture, thereby potentially reducing production costs. In one example, the wires have a single point of contact with the thermal insulator. One or more seals can be provided around the wires to seal the one or more gaps and be configured to prevent air from entering the thermally insulating space between the inner wall and the outer wall and to hold the wires in place.

[0020] Preferably, the heating apparatus further comprises a thermocouple cable and / or a thermistor wire configured to connect the heating element to a control circuit. In this way, the temperature of the heating element can be monitored and / or controlled by the control circuit.

[0021] According to another aspect of the application, there is provided an aerosol generating device configured to generate an aerosol for inhalation by a user, the aerosol generating device comprising a heating apparatus according to the first aspect.

[0022] According to another aspect of the application, there is provided a method of manufacturing a heating apparatus according to the first aspect, the method comprising the steps of: providing an inner wall to define a heating zone, the inner wall comprising an opening through which aerosol-forming substance can be received in the heating zone; arranging a heating element on the inner wall, the heating element being configured to provide heat to the received aerosol-forming substance; providing an outer wall radially outwardly relative to the inner wall; welding a bridge connecting the inner wall to the outer wall to enclose the inner wall and the outer wall; and cutting a recess in the bridge. BRIEF DESCRIPTION OF DRAWINGS

[0023] Embodiments of the application will now be described, by way of example, with reference to the accompanying drawings, in which:

[0024] Figure 1 is a perspective view of an aerosol generating device comprising a heating apparatus according to an embodiment of the application;

[0025] Figure 2A and Figure 2B is a cross-sectional view of a heating apparatus according to an embodiment of the application;

[0026] Figure 3 is a cross-sectional view of a heating apparatus according to another embodiment of the application; and

[0027] Figure 4 is a cross-sectional view of another heating apparatus according to another embodiment of the application. DETAILED DESCRIPTION

[0028] As described herein, vapour should generally be understood to mean a substance that is in the gaseous phase at a temperature below its critical temperature, meaning that by increasing its pressure without lowering its temperature, the vapour can be condensed into a liquid, whereas an aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. It should be noted, however, that the terms “aerosol” and “vapour” can be used interchangeably in this specification, in particular with regard to the form of the inhalable medium generated for inhalation by a user.

[0029] Figure 1An aerosol generating device 2 according to an embodiment of the application is shown. The aerosol generating device 2 is shown in an assembled configuration in which exemplary internal components are visible. The aerosol generating device 2 is a heat-not-burn device, which can also be referred to as a tobacco-vapour device, and comprises a heating apparatus 4 configured to receive an aerosol substrate such as a rod of aerosol generating material (e.g. tobacco). The aerosol generating device 2 can comprise a power source (such as a battery) and control circuitry for controlling the supply of power from the power source to the heating apparatus 4. The heating apparatus 4 is operable to heat but not bum a rod of aerosol generating material to generate vapour or aerosol for inhalation by a user. Of course, it will be appreciated by the skilled person that Figure 1 The depicted aerosol generating device 2 is merely an exemplary aerosol generating device according to the application. Other types and configurations of tobacco-vapour products, vaporisers, or electronic cigarettes can also be used as aerosol generating devices according to the application.

[0030] Figure 2A A schematic view of a heating apparatus 10 having a heating cup 12 and an outer wall 14 is shown. The thermal insulation of the heating apparatus 10 is provided by the walls 16 of the heating cup 12, which act as the inner walls of the thermal insulation, and the outer wall 14 is the outer wall of the thermal insulation. The heating cup walls 16 are provided separately from the outer wall 14 to provide an insulating space 18, which can be a vacuum or filled with an insulating material such as air or aerogel or fibrous insulation. The skilled person will appreciate that the term “vacuum” refers to a space in which the pressure is significantly lower than atmospheric pressure due to the removal of free matter, in particular air. The quality of the vacuum formed between the inner walls 16 and the outer wall 14 can be a low vacuum, a medium vacuum, or a high vacuum.

[0031] The heating cup 12 is closed at a base end 19 thereof distal from an open end 20 of the heating cup 12 to limit the insertion depth of a consumable. In this example, the outer wall 14 has an open end 22 through which the heating cup 12 is received. The outer wall 14 can be part of a cup or sleeve, as will be explained with reference to Figure 3 and Figure 4 As such, the heating cup 12 is positioned radially within the inner surface of the outer wall 14.

[0032] The heating cup 12 and the outer wall 14 can be generally cylindrical in shape, such that if viewed from above or below (i.e. parallel to the longitudinal axis of the heating cup 12 and the outer wall 14), the heating cup 12 and the outer wall 14 appear as concentric circles (not shown). In alternative examples, the heating cup 12 and / or the outer wall 14 can be formed into other types of cross-sectional shape, such as a square or polygonal shape. From Figure 2A and Figure 2BAs can be seen, the open end 20 of the heating cup 12 can have a greater circumference or perimeter than the inner wall 16 (i.e. the wall of the heating cup), and there is a tapered conical section between the inner wall 16 and the open end 20. This is to improve the ease of insertion of the consumable / aerosol-forming substance (not shown) into the cavity / heating zone of the heating apparatus 10. In another example, the inner wall of the heating cup and the thermal insulator can be separate components, with the heating cup being received into the cavity defined by the inner wall.

[0033] The open end 20 of the heating cup 12 is connected to the open end of the outer wall by welding a bridge 24 between the open end of the heating cup and the open end 22 of the outer wall 14. The bridge 24 can be formed using the material of the inner wall 16 and the outer wall 14, or alternatively can use a weld filler material. As will be appreciated, the inner wall 16 and the outer wall 14 can each comprise a metallic material that can be welded together or to a separate bridge material, or alternatively the walls can comprise a glass material that is laser welded to the bridge material. The bridge 24 connection encloses the space 18 between the inner wall and the outer wall, which can comprise a vacuum or be filled with a thermal insulating material. Accordingly, the bridge 24 surrounds or encircles the open end 20 of the heating cup 12 and has a loop or annular shape.

[0034] Figure 2B The top end of the heating apparatus 10 and the exploded view of the bridge connection are shown in Figure 2A The bridge 24 connection is depicted in the exploded view in FIG. 4. As can be seen, the bridge 24 has a thickness 28 in the longitudinal direction of the heating apparatus 10 in order to provide structural integrity containing the vacuum or thermal insulating material. For example, the ends of the bridge 24 should be sufficiently bonded or welded to the respective inner or outer wall. In other words, the bridge 24 (which can also be referred to as a weld ring or connection ring) must have sufficient thickness to ensure there is sufficient surface area for welding the inner and outer walls to the bridge 24. Additionally, the bridge 24 must be thick enough to prevent it from collapsing on itself (e.g. under vacuum pressure).

[0035] It has been found that the thickness 28 of the bridge 24 can be reduced to a predetermined minimum thickness 30 to reduce the amount of thermally conductive weld / bridge material, while maintaining the structural and physical integrity of the bridge 24. As will be appreciated by those skilled in the art, the predetermined minimum thickness 30 of the bridge 24 can vary depending on the mass of the vacuum or thermal insulating material provided between the inner wall 16 and the outer wall 14. The predetermined minimum thickness 30 of the bridge 24 can also depend on the material of the bridge 24.

[0036] In order to reduce the bridge thickness 28 to the predetermined minimum thickness 30, a groove 32 is cut into the bridge 24 material. This can be performed by grinding or cutting, or other machining methods in the art. From Figure 2BAs can be seen, a V-shaped groove 32 is cut into the lower surface of the bridge 24. However, any shaped groove 32 can be used and the groove 32 can be cut into the upper surface of the bridge 24 as needed for design or manufacturing processes. In another example, a groove can be cut into both the upper and lower surfaces of the bridge 24 to achieve a predetermined minimum thickness 30. Importantly, the amount of material of the bridge 24 is reduced to a minimum thickness between the inner wall 16 and the outer wall 14 along the length of the bridge 24 to introduce a thermal break to prevent heat loss or heat transfer out of the heating cup 12 / heating zone of the heating apparatus 10.

[0037] Figure 3 A schematic view of a heating apparatus 50 is shown having an inner cup 52 and an outer cup 54. The heating apparatus 50 includes an insulator comprising an inner wall 56 and an outer wall 58 which are the walls of the inner cup 52 and the outer cup 54 respectively. The inner wall 56 also defines an opening 60 through which an aerosol-forming substance or consumable can be received in a heating zone 62 of the heating apparatus 50. The inner cup 52 is made of a metallic material with good thermal conductivity properties, such as stainless steel. The opening 60 serves as an entry point for insertion of the consumable in its configured form into the heating apparatus 50. The inner cup 52 is closed at its base to limit the insertion depth of the consumable. The outer cup 54 comprises a metallic material, such as steel or stainless steel, and also has a closed end. The inner cup 52 and the outer cup 54 can also be formed of other materials, such as glass.

[0038] The inner cup 52 is positioned radially within an inner surface of the outer cup 54. The inner cup 52 and / or the outer cup 54 can have a circular cross-section or be formed into other types of cross-sectional shapes, such as square or polygonal.

[0039] In this example, the inner cup 52 has a lip 64 at its open end. The lip 64 points outwardly towards the outer cup 54. It will be appreciated that the lip 64 is an optional feature and can be removed as needed for design or manufacturing constraints.

[0040] The heating apparatus 50 further includes a bridge 66 as a welded connection between the inner cup 52 and the outer cup 54. Accordingly, the bridge 66 surrounds the open end of the inner cup 52 in a loop or annular shape and encloses an insulating space 67 between the outer surface of the inner cup 52 and the inner surface of the outer cup 54 to provide the insulator. The space 67 can be filled with a vacuum or other insulating material.

[0041] As described above with reference to Figure 2A and Figure 2B The bridge 66 can be formed using the materials of the inner cup 52 and the outer cup 54 or by using a weld filler material. The bridge 66 has a thickness in the longitudinal direction of the heating apparatus 50 to provide structural integrity and maintain an effective bond with the respective inner and outer cups.

[0042] The bridge 66 includes a recess 68 cut into the material of the bridge 66, which reduces the thickness of the bridge 66 at the recess 68. This can be performed by grinding or cutting, or other machining methods in the art. As can be seen in Figure 3 the V-shaped recess 68 is cut into the upper surface of the bridge 66 to provide a predetermined minimum thickness of bridge material at the apex of the recess 68. However, any shape of recess can be used, and the recess can be cut into the upper surface of the bridge according to design or manufacturing processes. The amount of material of the bridge 66 is thus reduced to a predetermined minimum thickness at the apex of the recess between the inner wall 56 and the outer wall 58 along the length of the bridge 66 to provide a thermal break to prevent heat loss or transfer of heat away from the inner cup 52 / heating zone 62 of the heating apparatus 50.

[0043] In Figure 3 the heater 70 is provided on the outer surface of the inner cup 52 (i.e. such that the heater is provided in the thermally insulating space 67). The heater 70 is a resistive track which can be printed or coated on the inner cup 52. Alternatively, the heater 70 can be laminated on the inner cup 52. Electrical wires 72 connect the heater 70 to a power source or printed circuit board assembly PCBA (not shown). The heating apparatus 50 also optionally includes a thermocouple or thermistor wire 74 which is connected to the PCBA to monitor and / or control the temperature of the heater 70. The electrical wires 72 and thermocouple / thermistor wire 74 can pass through holes in the base of the outer cup 54 (which holes can then be suitably sealed). Alternatively, if the outer cup comprises a glass material, the electrical wires can be moulded into the base end.

[0044] Figure 4 Another schematic view of a heating apparatus 90 is shown, having an inner sleeve 92 and an outer sleeve 94. The inner sleeve 92 comprises the inner wall of the heating apparatus 90 which defines an opening 96 through which a consumable can be received in a heating zone 98 of the heating apparatus 90. The opening 96 acts as an entry point for insertion of a consumable in its configured form into the heating apparatus 90, and the inner sleeve 92 comprises a metallic material having good thermal conductive properties.

[0045] The outer sleeve 94 comprises the outer wall of the heating apparatus 90 and can be made of a metallic material such as steel or stainless steel which is easily formed into a tubular or cylindrical shape. The inner sleeve 92 is positioned radially within the inner surface of the outer sleeve 94. The thermal insulation of the heating apparatus 90 comprises a space 99 between the inner sleeve 92 and the outer sleeve 94 in which a vacuum or thermally insulating material is provided. The inner and outer sleeves can comprise another material other than a metallic material, such as glass.

[0046] The inner sleeve 92 has a top lip 100 and a bottom lip 102 at the top and bottom ends of the inner sleeve 92, respectively. The top and bottom lips 100, 102 point outwardly toward the outer sleeve 94. As described with reference to Figure 3 the inner sleeve 92, the lips are optional features.

[0047] The inner sleeve 92 further optionally includes a plug 104 positioned within the inner sleeve 92 to act as a seat for an inserted consumable. The plug 104 can be annular or have an aperture to allow airflow through the plug 104, or alternatively can be a solid block to prevent airflow.

[0048] The heating apparatus 90 further includes bridges 106 welded between the inner and outer sleeves at the upper and lower ends of the sleeves. Accordingly, the bridges 106 encircle the open ends of the inner sleeve 92 in respective loops or annular shapes, and envelope the space 99 between the outer surface of the inner sleeve 92 and the inner surface of the outer sleeve 94. As described above with reference to FIGS. 2 and Figure 3 the bridges 106 can be formed using the material of the sleeves, or by using a weld filler material.

[0049] Each bridge 106 has a thickness 108 in the longitudinal direction of the heating apparatus 90 to provide structural integrity and maintain an effective bond with the respective inner and outer sleeves. Each bridge 106 further includes a groove 110 cut into the bridge 106 material, which reduces the thickness of the bridge 106 at the groove 108.

[0050] It can be seen in Figure 4 that a U-shaped groove 108 is cut into the outer surface of the bridge 106 to provide a predetermined minimum thickness of bridge material. However, any shape of groove can be used, and the groove can be cut into any surface of the bridge according to design or manufacturing processes. The amount of material of the bridge 106 is thus reduced between the inner and outer sleeves 92, 94 along the length of the bridge 106 to the predetermined minimum thickness to provide a thermal break to prevent heat loss or heat transfer away from the heating zone 98 of the heating apparatus 90.

[0051] The heating apparatus 90 includes a heater or heating element 112, electrical wires 114, and a thermistor wire 116, similar to those described above with reference to the heating apparatus 50 described above. Figure 3 The heating element 112 is disposed on the outer surface of the inner sleeve 92 in the thermally insulating space 99 (between the inner and outer sleeves). The heating element can be a resistive track that can be printed or coated on the inner sleeve 92. Alternatively, the heater 112 can be laminated on the inner sleeve 92.

[0052] Electrical wires 114 connect the heating element 112 to a power source or PCBA (not shown). A thermocouple or thermistor wire 116 is connected to the PCBA to monitor and / or control the temperature of the heating element 112. In this example, the electrical wires 114 pass through the bottom lip 102 of the inner sleeve 92 away from the lower welded bridge 110. However, other designs and arrangements of the electrical wires 114 in the heating apparatus 90 will be apparent to the skilled person. The thermocouple / thermistor wire 116 can pass through a hole in the plug 104, which can then be suitably sealed. Alternatively, if the plug 104 comprises a glass material, the thermistor wire 116 can be moulded into the plug 104.

Claims

1. A heating device for an aerosol generating apparatus, the heating device comprising: An insulating body includes an inner wall and an outer wall, the inner wall defining a heating zone and including an opening through which an aerosol-forming substance can be received in the heating zone, and the outer wall being radially outwardly positioned relative to the inner wall. The insulation further includes a welded bridging member connecting the inner wall and the outer wall, wherein the welded bridging member includes a groove; and A heating element is disposed on the inner wall and configured to provide heat to the received aerosol-forming material.

2. The heating device as described in claim 1, wherein, The welded bridging component is a loop, preferably wherein... The loop is circular.

3. The heating device as described in claim 1 or 2, wherein, The welded bridging component has a predetermined minimum thickness.

4. The heating device as described in claim 1, 2, or 3, wherein, The welded bridging component includes filler material.

5. The heating device as claimed in any of the preceding claims, wherein, The outer wall is arranged at a predetermined distance from the inner wall.

6. The heating device as claimed in any of the preceding claims, wherein, A vacuum is sealed between the inner wall and the outer wall.

7. The heating device according to any one of claims 1 to 5, wherein, The insulation further includes insulating material located between the inner wall and the outer wall.

8. The heating device as claimed in any of the preceding claims further includes a heating cup, the heating cup including the inner wall and an end for limiting the insertion depth of the received aerosol-forming substance.

9. The heating device according to any one of claims 1 to 7, further comprising a heating sleeve, the heating sleeve including the inner wall.

10. The heating device as claimed in any of the preceding claims, wherein, The heating element is disposed between the inner wall and the outer wall.

11. The heating device as claimed in any of the preceding claims, wherein, The heating element includes resistive rails printed, coated, or wound on the inner wall.

12. The heating device as claimed in any of the preceding claims further includes one or more wires configured to connect the heating element to a power source capable of supplying power to the heating element.

13. The heating device as claimed in any of the preceding claims further includes thermocouple cables and / or thermistor wires configured to connect the heating element to a control circuit.

14. An aerosol generating apparatus configured to generate an aerosol for inhalation by a user, the aerosol generating apparatus comprising the heating device according to claims 1 to 13.

15. A method of manufacturing a heating device as described in any one of claims 1 to 13, the method comprising the following steps: An inner wall is provided to define a heating zone, the inner wall including an opening through which aerosol-forming material can be received in the heating zone; A heating element is arranged on the inner wall, which is configured to provide heat to the received aerosol-forming material; Provide an outer wall that extends radially outward relative to the inner wall; Welding a bridging member connecting the inner wall to the outer wall to enclose the inner wall and the outer wall; and Cut a groove in the bridging component.

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