Heating assembly for an aerosol generating device

Abstract

A heating assembly for an aerosol generating device is disclosed, the heating assembly (100) comprising: an outer tube (102) having a first end and a second end; a heater cup (104) arranged radially inwardly of the outer tube, the heater cup comprising a heating element (106) provided on an outer facing surface of the heater cup, the heater cup having an opening at a first end of the outer tube for receiving an aerosol forming substrate; electrical connectors (112) configured to supply electrical power to the heating element; a base portion (114) arranged at a closed end of the heater cup, the base portion comprising one or more slots in which the electrical connectors can be received; and an end wall (110) arranged at the second end of the outer tube, from which the electrical connectors extend, wherein the base portion is configured to radially inwardly bias at least a portion of each of the electrical connectors toward the heating element when they are received in the slots in order to press the electrical connectors towards heating element.

Description

[0001] HEATING ASSEMBLY FOR AN AEROSOL GENERATING DEVICE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a heating apparatus for an aerosol generating device and an aerosol generating device comprising a heating apparatus. The disclosure is particularly applicable to a portable aerosol generating device, which may be self-contained and low temperature. In particular, the invention relates to an aerosol generating device with a heater disposed within a vacuum or insulator chamber.

[0004] BACKGROUND

[0005] Aerosol generating devices such as heat-not-burn device generate an aerosol or vapour by heating an aerosol forming substrate or consumable that typically comprises moist leaf tobacco or other suitable material to a temperature typically in the range of 150°C to 300°C. Heating the aerosol forming substrate, but not combusting or burning it, releases an aerosol sought by the user in a way that does not include the undesirable byproducts of combustion. For example, the aerosol produced by heating tobacco does not typically include the burnt or bitter taste that may result from combustion.

[0006] Within such aerosol generating devices, it is desirable to improve the efficiency of the heating operation such that the battery life of the device may be extended. To this end, insulators have been implemented within aerosol generating devices in order to thermally insulate the cavity in which an aerosol substrate is heated, thereby limiting thermal losses to the external environment.

[0007] However, heating assemblies including vacuum insulators are difficult to manufacture. A particular problem to overcome when producing this type of heating apparatus is how to provide an effective electrical connection between a power source outside the insulating chamber and a heating element inside the insulating chamber whilst maintaining an effective vacuum or insulating space in the heater assembly. An object of the invention is to address this problem. SUMMARY OF INVENTION

[0008] According to an aspect of the invention, there is provided a heating assembly for an aerosol generating device, comprising: an outer tube having a first end and a second end; a heater cup arranged radially inwardly of the outer tube, the heater cup comprising a heating element provided on an outer facing surface of the heater cup, the heater cup having an opening at a first end of the outer tube for receiving an aerosol forming substrate; electrical connectors configured to supply electrical power to the heating element; a base portion arranged at a closed end of the heater cup, the base portion comprising one or more slots in which the electrical connectors can be received; and an end wall arranged at the second end of the outer tube, from which the electrical connectors extend, wherein the base portion is configured to radially inwardly bias at least a portion of each of the electrical connectors toward the heating element when they are received in the slots in order to press the electrical connectors towards heating element.

[0009] In this way, a direct electrical connection is effectively formed between the electrical connectors and the heating element without the need for soldering (as is the case in known heating assemblies). Typically, such soldered connections between electrical connectors and a heating element are made in a vacuum, which present various hurdles in the design and manufacturing stages. For instance, surfaces must be kept clean before soldering as well as needing to be cleaned after soldering. By preventing the use of solder and fluxes reduces the risk of outgassing and any undesirable pressure increase in the insulating space between the heater cup and the outer tube which reduces the insulation capacity of a vacuum insulator.

[0010] The base portion in the present invention is configured to cause the electrical connectors to be pushed toward the centre of the outer tube such that a direct electrical connection is formed when the heater cup (and heating assembly) is pressed or inserted into the space between the electrical connectors. The radially inward biasing of the electrical connectors by the base portion ensures that a good electrical connection is reliably maintained for the working lifetime of the heating assembly. As should be appreciated, the electrical connection between the heating element and the electrical connectors may undergo more than ten thousand heating and cooling cycles in its operational life, which may lead to an undesirable loss of material flexibility / elasticity or material loss of the electrical connectors and / or heating element and cause an unreliable electrical connection. Advantageously, the present base portion provides a biasing physical limitation on the electrical connectors to maintain a reliable electrical connection with the heating element.

[0011] Preferably the one or more slots are open at radially inward sections in the base portion. In this way, the base portion can radially inwardly bias the at least one portion of the respective electrical connectors directly into the heating element of the heater cup and ensure that a good electrical connection is maintained throughout the lifetime of the heating assembly.

[0012] Preferably, the one or more slots comprises one or more respective surfaces arranged radially outwardly of each of the at least a portion of the received electrical connectors. The electrical connectors may each comprise a predetermined length that extends from the base portion and the second end of the outer tube, and the base portion may bias the fully predetermined length of an electrical connector or only a portion of the predetermined length. In some cases, some portions of a biased electrical connector may flex radially outwardly, away from the heater cup. Therefore, the base portion may be configured to ensure that any radially outward bias of the electrical connectors is limited to ensure that a good electrical connection is maintained between the electrical connectors and the heating element. The base portion may be in the shape of a ring, which provides a single surface that surround the electrical connectors. Alternatively, the slots may comprise separate surfaces for the respective electrical connectors.

[0013] Preferably, the base portion is configured to be removably attachable to the heater cup and / or the end wall. In this way, the base portion can be easily attached or removed to attach to the heater cup and / or the end wall during the assembly of the heating assembly. It should be appreciated that the base portion provides the radially inwardly biasing force on the electrical connectors when the electrical connectors are received in the one or more slots of the base portion. To ensure good alignment of the electrical connectors with the heating assembly, the heating assembly may further comprise a form-fit connection configured to substantially align the electrical connectors with electrical contacts of the heating element. The form-fit connection may be between the subassembly of the base portion and the heater cup or the base portion and the end wall. Alternatively, the heater cup and the end wall (with the base portion attached) may each have a form-fit connection with the outer tube. For example, the outer tube may comprise a notch or groove at each end, and the heater cup and the end wall may each comprise a corresponding tongue to fit in the respective notch / groove. In this way, the form-fit connection can effectively ensure that the electrical connectors line up with corresponding electrical contacts in the heating element. It will be apparent to the skilled person that the form-fit connection may designed or suitable materials may be selected to minimise any undesirable heat loss.

[0014] The one or more slots in the base portion may have a length that is less than the length of the electrical connectors so that the electrical connectors are axially compressed within the slots, thereby biasing the electrical connectors radially inwardly. The base portion may comprise a ledge ora bevelled surface configured to axially compress the electrical connectors to bias the electrical connectors radially inwardly. The electrical connectors may each comprise an end, where the ends are pressed against the ledge or be biased by the bevelled surface to flex, bend or crumple the electrical connectors radially inwardly. In this way, the axial compression causes a radial extension or expansion of the electrical connectors in a reliable way.

[0015] The electrical connectors may have a curved shape or a sinuous shape to facilitate the radially inwardly biasing of the respective at least a portion of the received electrical connectors. In this way, each of the electrical connectors may be axially compressed to form the contact points with the heating element. The electrical connectors may be shaped or designed to crumple or fold into a zig-zag or wavy arrangement. Such an arrangement may cause multiple radially inwardly extensions of the electrical connectors, which in turn provide multiple contact points between the electrical connectors and the heating element. Preferably, the base portion comprises a non-outgassing material such as ceramic or polyetheretherketone, PEEK. In this way, the base portion will not cause any pressure increase in the insulating space between the heater cup and the outer tube when heat is generated by the heating element. In addition, materials such as ceramic or PEEK can provide effective insulation properties.

[0016] Preferably, a vacuum is enclosed between the outer tube, the heater cup and the end wall. In this way, a vacuum is provided when the base portion is connected to the outer tube to provide a vacuum insulator. Alternatively, an insulating material may be enclosed between the outer tube, the heater cup and the end wall. Examples of insulating materials which can be provided include, but are not limited to: air, aerogel materials, powders or fibrous insulating materials.

[0017] Preferably, the end wall fully covers the second end of the outer tube. In this way, the manufacturing of the heating assembly can be simplified where the attachment of the end wall to the outer tube connects the electrical connectors to the heating element whilst also closing off the outer tube.

[0018] Preferably, the end wall is welded or brazed to the outer tube. In this way, the integrity of the insulating space, e.g. vacuum, between the outer tube and the heater cup is improved.

[0019] Preferably, an inner surface of the heater cup is electrically insulated. In this way, the electrical safety of the heating assembly is improved. The electrical insulation may be provided as a separate layer or the heater cup material may be selected as an electrically insulating material.

[0020] Preferably, the end wall further comprises a connection point. The connection point may comprise an access hole into a space between the outer tube and the heater cup through which a vacuum can be formed in the space. The access hole may be sealed after the vacuum is formed. As an example, a conduit may be connected to the access hole to generate the vacuum in the space and the conduit may be pinched or otherwise sealed to close off the access hole to retain the vacuum in the space. In another example, the vacuum in the heating assembly may be formed by manufacturing the heating assembly in a vacuum chamber and plugging the access hole after the vacuum is formed in the space.

[0021] The connection point may be configured to allow a structural element to connect the heating assembly to an aerosol generating device. Since the connection point is part of the end wall, a structural element extending from the base portion to a device would limit any conductive heat loss or heat transfer from the heater cup to the device. Preferably, the heating assembly further comprises a structural member arranged to fix the heating assembly to an aerosol generating device.

[0022] Preferably, the heating element is a resistive heater. In this way, a compact, simple and easy-to-power form of heater is provided.

[0023] According to another aspect of the invention, there is provided an aerosol generating device configured to generate an aerosol for inhalation by a user, the aerosol generating device comprising: the heating assembly according to the first aspect; and a power source to provide electrical power to the heating element through the electrical connectors.

[0024] According to yet another aspect of the invention, there is provided a method of manufacturing the heating assembly for an aerosol generating device, the method comprising the steps of: providing an outer tube, the outer tube having a first end and a second end; arranging a heater cup radially inwardly of the outer tube, the heater cup comprising a heating element provided on an outer facing surface of the heater cup and having an opening at a first end of the outer tube for receiving an aerosol forming substrate; providing an end wall to be arranged at the second end of the outer tube; extending electrical connectors from the end wall, the electrical connectors configured to supply electrical power to the heating element; providing a base portion to be arranged at a closed end of the heater cup, the base portion comprising one or more slots in which the electrical connectors can be received; inserting the electrical connectors into the one or more slots of the base portion, wherein the base portion is configured to radially inwardly bias at least a portion of each of the electrical connectors toward the heating element when they are received in the slots in order to press the electrical connectors towards heating element; and attaching the end wall to the second end of the outer tube.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] Embodiments of the invention are now described, by way of example, with reference to the drawings, in which:

[0027] Figure 1 is a perspective view of an aerosol generating device comprising a heating apparatus according to an embodiment of the invention;

[0028] Figure 2 is a cross-sectional view of an aerosol forming consumable;

[0029] Figures 3A, 3B and 3C are schematic views of a heating assembly according to an embodiment of the invention; and

[0030] Figure 4 is a cross-sectional schematic view of a base portion and an end wall of a heating apparatus according to another embodiment of the invention..

[0031] DETAILED DESCRIPTION

[0032] 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.

[0033] Figure 1 illustrates an aerosol generating device 2 according to an embodiment of the invention. The aerosol generating device 2 is illustrated in an assembled configuration with exemplary internal components visible. The aerosol generating device 2 is a heat-not-burn device, which may also be referred to as a tobaccovapour 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 may comprise a power source such as a battery and control circuitry for controlling the supply of power from the power source to the heating assembly 4. The heating assembly 4 is operable to heat, but not bum, the rod of aerosol generating material to produce a vapour or aerosol for inhalation by a user. Of course, the skilled person will appreciate that the aerosol generating device 2 depicted in Figure 1 is simply an exemplary aerosol generating device according to the invention. Other types and configurations of tobacco-vapour products, vaporisers, or electronic cigarettes may also be used as the aerosol generating device according to the invention.

[0034] Figure 2 shows a schematic view of an aerosol forming consumable 6 for insertion into the heating apparatus 4 of the aerosol generating device 2. The aerosol forming consumable 6 has a cylindrical body 8, in which is provided a filter 10 toward a first end and an aerosol forming substance 12 at a second end of the body 8. The aerosol forming substance 12 may be a solid or semi-solid aerosol forming substrate which comprises tobacco. Aerosol forming consumable 6 further includes an empty space 14 positioned in the body 8 between the filter 10 and the aerosol forming substance 12. This space 14 collects aerosol that is formed or generated from the aerosol forming substance 12 when it is heated, before the generated aerosol is inhaled by a user through the filter 10.

[0035] The aerosol forming consumable 6 also includes a wrapping material 16 which holds the filter 10 and aerosol forming substance 12 in place and provide the space 14 between the filter 10 and aerosol forming substance 12. The wrapping material 16 has suitable properties to ensure the integrity of the aerosol forming consumable 6, for example such that it does not crumple and collapse into the space 14 on insertion into a heating apparatus, or tear as the aerosol forming consumable is extracted from the heating apparatus. The space 14 may be formed a tubular member made of a stiff paper material that provides a degree of rigidity whilst allowing generated aerosol to easily flow through the space 14 to the filter 10. The length of the aerosol forming substance 12 in the body 8 may be similar to the length in a longitudinal direction of the heating region in the present heating assembly.

[0036] Figures 3A, 3B and 3C illustrate a heating assembly 100 in different stages of manufacturing assembly according to an embodiment of the invention. The heating assembly 100 includes an outer tube 102 and a heater cup 104 provided radially within the outer tube 102. The heater cup 104 is joined to the outer tube 102 by welding or any another means apparent to the skilled person at a first end of the heating assembly 100.

[0037] The heater cup 104 defines a cavity in which an aerosol generating consumable, such as a tobacco rod or aerosol forming consumable 6, may be received. The heater cup 104 further comprises a heating element 106 arranged on an outer surface of the heater cup 104. The heating element 106 is configured to generate heat when an electrical current passes through it, and where the generated heat is transferred through the heater cup wall by conduction so as to heat the air and the consumable received in the cavity. The heating element 106 can be powered by a battery or other form of power source in an aerosol generating device.

[0038] The outer tube 102 and heater cup 104 have approximately elliptical or circular cross-sections when viewed along one of its ends parallel to its longitudinal axis to provide a substantially cylindrical shaped heating assembly 100. However, in alternative embodiments, the heating assembly 100 may be formed in other cross- sectional shapes, for example shapes that are approximately square or polygonal.

[0039] The heater cup 104 and the outer tube 102 are spaced radially apart from one another to define an enclosed insulating space 108 between them in which a vacuum may be formed. The skilled person will understand that the term “vacuum” refers to a space in which the pressure is considerably lower than atmospheric pressure due to the removal of free matter, in particular air. The quality of the vacuum formed between the heater cup 104 and the outer tube 102 may be a low vacuum, a medium vacuum, or a high vacuum. In alternative embodiments, instead of a vacuum, an insulating material may be disposed between the heater cup 104 and the outer tube 102, such as powder, fibrous material such as aerogel, and / or air.

[0040] The heating element 106 is a resistive heating element that generates heat by resistive heating. In the present disclosure, the heating element 106 is a track that surrounds the heater cup 104, preferably around the entire circumference of the heater cup 104. Different heating element 106 patterns or arrangements will be apparent to the skilled person. For example, the heating element 106 may comprise a heating sheet which partially or entirely surrounds heater cup 104. In another example, the heating element 106 may be printed, coated or otherwise attached onto the outer surface heater cup 104. The heating element 106 further comprises a first electrical contact and a second electrical contact (not shown) located toward the bottom end of the heater cup 104 for the electrical connection to a power source.

[0041] The heating assembly 100 further comprises an end wall 110 which is shaped to cover the bottom end of the outer tube 102 and to enclose a vacuum or the insulating space 108 between the heater cup 104 and the outer tube 102. The outer tube 102 and the end wall 110 may each comprise a metal such as stainless steel so that the two components may be welded or brazed together to seal the connection.

[0042] The heating assembly 100 further comprises electrical connectors 112 which are configured to connect the heating element 106 to a power source or battery in an aerosol generating device. The electrical connectors 112 may be wires or ribbons of an electrically conductive material, such as a metal (e.g. spring steel, stainless steel or copper). The material of the electrical connectors 112 is configured to flex, crumple or be otherwise biased to a desired degree without breaking. The electrical connectors 112 extend from the end wall 110 into the space 108 between the heater cup 104 and the outer tube 102 to contact the electrical connects of the heating element 106. As will be appreciated by the skilled person, the electrical connectors 112 may be electrically insulated from the end wall 110 and outer tube 102 by use of non-electrically conductive seals (not shown). The heating assembly 100 further comprises a ring-shaped base portion 114 comprising one or more slots, which is configured to fit around the electrical connectors 112 such that the electrical connectors 112 extending from the end wall 110 are received in the slots of the base portion 114. The base portion 114 is made from a non-electrically conductive material such as a ceramic or nonoutgassing plastic such as polyetheretherketone, PEEK.

[0043] As can be seen in Figures 3A and 3B, the base portion 114 fits around the electrical connectors 112 such that a surface of the one or more slots radially inwardly bias the electrical connectors 112 toward the centre of the insulating space 108 before the end wall 110 and base portion 114 are inserted into the outer tube 102. It can be understood that as the heater cup 104 descends into the base portion 114 (or as the end wall 110 and base portion are inserted into the outer tube 102 and onto the heater cup 104) an electrical connection 116 is formed between the electrical connectors 112 and the electrical contacts of the heating assembly 106, as shown in Figure 3C. Since the electrical connectors 112 are radially inwardly biased into the space of the heater cup 104, the electrical connectors 112 are pressed directly against heating element 106 when the heater cup 104 is received in the base portion 114.

[0044] In this specific example, the base portion 114 includes a ledge 118 or bevelled surface against which the electrical connectors 112 are pushed against to axially compress the electrical connectors 112. The axial compression causes the electrical connectors 112 to crumple into a zig-zag shape and extend radially towards the centre of the outer tube 102 1 heating assembly 100.

[0045] The end wall 110 further comprises an aperture 120 which acts as a connection point for a vacuum generator tube 122, where during assembly, the vacuum generator tube 122 may be used to form a vacuum in the insulating space 108 before the aperture 120 or vacuum generator tube 122 is sealed. The aperture 120 may also be used to allow one or more sensors to be attached to the end wall 110, such as a temperature or pressure sensor for the heating assembly 100. In yet another example, the aperture 120 may be used to connect the heating assembly 100 to an aerosol generating device by providing a rigid structural element and to secure the heating assembly 100 in place.

[0046] Figure 4 shows a schematic profile view of an end wall 210 and a base portion 212 according to another example of the present disclosure. The end wall 210 largely corresponds with the example shown in Figure 3. However, in this specific example, the electrical connectors 214 are shown to flex radially inwardly as a singular curved bow when axially compressed by the ledge 216 of the base portion 212.

[0047] As should be understood from the examples in Figures 3 and 4, electrical connectors may be caused to crumple to form a zig-zag shape, or may be caused to bow or flex radially inwardly when axially compressed against the ledge of a base portion. This may depend on the initial shape and dimensions of the electrical connectors and the design of the base portion. Other designs of a base portion that cause the electrical connectors to be radially inwardly biased to form a direct electrical connection with the heater cup on assembly would be apparent to the skilled person.

Claims

CLAIMS1 . A heating assembly for an aerosol generating device, comprising: an outer tube having a first end and a second end; a heater cup arranged radially inwardly of the outer tube, the heater cup comprising a heating element provided on an outer facing surface of the heater cup, the heater cup having an opening at a first end of the outer tube for receiving an aerosol forming substrate; electrical connectors configured to supply electrical power to the heating element; a base portion arranged at a closed end of the heater cup, the base portion comprising one or more slots in which the electrical connectors can be received; and an end wall arranged at the second end of the outer tube, from which the electrical connectors extend, wherein the base portion is configured to radially inwardly bias at least a portion of each of the electrical connectors toward the heating element when they are received in the slots in order to press the electrical connectors towards heating element.

2. The heating assembly of claim 1 , wherein the one or more slots are open at radially inward sections in the base portion.

3. The heating assembly of claim 1 or 2, wherein the one or more slots comprises one or more respective surfaces arranged radially outwardly of each of the at least a portion of the received electrical connectors.

4. The heating assembly of claims 1 , 2 or 3, wherein the base portion is configured to be removably attachable to the heater cup and / or the end wall.

5. The heating assembly of any of the preceding claims, wherein the one or more slots in the base portion have a length that is less than the length of theelectrical connectors so that the electrical connectors are axially compressed within the slots, thereby biasing the electrical connectors radially inwardly.

6. The heating assembly of any of the preceding claims, wherein the electrical connectors have a curved shape or a sinuous shape to facilitate the radially inwardly biasing of the respective at least a portion of the received electrical connectors.

7. The heating assembly of any of the preceding claims, wherein the base portion comprises a non-outgassing material such as ceramic or polyetheretherketone, PEEK.

8. The heating assembly of any of the preceding claims, wherein a vacuum is enclosed between the outer tube, the heater cup and the end wall.

9. The heating assembly of any of the preceding claims, wherein the end wall is welded or brazed to the outer tube.

10. The heating assembly of any of the preceding claims, wherein an inner surface of the heater cup is electrically insulated.

11. The heating assembly of any of the preceding claims, wherein the end wall comprises a connection point.

12. The heating assembly of claim 11 , wherein the heating assembly further comprises a structural member arranged to fix the heating assembly to an aerosol generating device.

13. The heating assembly of any of the preceding claims, wherein the heating element is a resistive heater.

14. An aerosol generating device configured to generate an aerosol for inhalation by a user, the aerosol generating device comprising:the heating assembly according to any of claims 1 to 13 and a power source to provide electrical power to the heating element through the electrical connectors.

15. A method of manufacturing the heating assembly for an aerosol generating device, the method comprising the steps of: providing an outer tube, the outer tube having a first end and a second end; arranging a heater cup radially inwardly of the outer tube, the heater cup comprising a heating element provided on an outer facing surface of the heater cup and having an opening at a first end of the outer tube for receiving an aerosol forming substrate; providing an end wall to be arranged at the second end of the outer tube; extending electrical connectors from the end wall, the electrical connectors configured to supply electrical power to the heating element; providing a base portion to be arranged at a closed end of the heater cup, the base portion comprising one or more slots in which the electrical connectors can be received; inserting the electrical connectors into the one or more slots of the base portion, wherein the base portion is configured to radially inwardly bias at least a portion of each of the electrical connectors toward the heating element when they are received in the slots in order to press the electrical connectors towards heating element; and attaching the end wall to the second end of the outer tube.

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