Patent Application
20250017270
The invention relates to a heating apparatus for an aerosol generating device. Specifically, the invention relates to a heating apparatus with a vacuum insulator.
Heating apparatuses for aerosol generating devices often have heaters that can become damaged during use or manufacturing, especially when these heaters are provided together with a vacuum insulator. Accordingly, there is a demand for more robust heating apparatuses. It is also desirable that aerosol generating devices can be made as efficient as possible, so that the battery life can be extended and thus the convenience for the user can be increased. It is an object of the present invention to address these demands.
According to a first aspect of the invention, there is provided a heating apparatus for an aerosol generating device, comprising: an insulator, comprising an inner wall and an outer wall that are separated from one another; a cavity in which an aerosol forming substance can be received, positioned adjacent the inner wall of the insulator; a heater provided inside the insulator on the inner wall, configured to heat an aerosol forming substance received in the cavity by thermal conduction to generate an aerosol; a first connection pad provided on the inner wall, configured to electrically connect the heater to a power source; wherein the first connection pad is joined to the outer wall and the inner wall to seal the insulator, and wherein the heater is spaced apart from the outer wall; wherein the first connection pad at least partially covers the heater to provide a protective layer over the heater.
In this way, the first connection pad is “sandwiched” between the inner and outer walls. It has been found that it is preferable to sandwich the first connection pad in this way, rather than sandwiching the heater or other fragile electrical connections since the pressure and forces exerted on the heater (or other components) is avoided during use and during manufacturing. The reduction of forces on the heater can help prevent it from becoming damaged. Therefore providing a separate connection pad at the join between the inner and outer walls creates a more robust heating apparatus which minimises the likelihood of damage to important and potentially fragile components. Additionally, spacing the heater apart from the outer wall means the heater only heats the necessary parts of the inner wall. Thus, heat can be delivered more efficiently to the aerosol generating substance while minimising the heat lost via conduction through the outer wall. The first connection pad and the heater can be provided as a single integral piece or closely abutting one another to create an electrical connection. The insulator can contain any suitable insulating medium, for example gasses such as air, or powdered or fibrous insulating materials. In other embodiments, the insulator can enclose a vacuum. The inner and outer walls of the insulator may comprise a material with higher thermal conductivity than an insulating layer or material contained inside the insulator to allow heat to be transferred from the heater to the cavity.
Preferably, the inner wall and the outer wall are separated by a vacuum such that the insulator is a vacuum insulator, and the first connection pad is joined to the outer wall and the inner wall to seal the vacuum inside the vacuum insulator. In this way, the connection pad is particularly effective because the forces required to create a tight join required to seal a vacuum insulator may be significantly larger than for other types of insulators. Such forces can pose a particular risk to the heater during manufacturing.
Preferably, the first connection pad is configured to have an increased mechanical robustness with respect to the heater. In this way, the first connection pad can be made resistant to damage during use or manufacturing while avoiding the need to change the properties of the heater to increase the robustness of the heater. The first connection pad can comprise a metal, such as stainless steel or copper. Other mechanically robust materials could also be used.
Preferably, the heater comprises an electrically resistive track that is printed or coated onto the inner wall. In this way, heat can be delivered efficiently to the inner wall. Coated heating elements may be particularly fragile, and therefore the providing a first connection pad at the join between the inner and outer walls significantly improves the robustness of the heating apparatus. The resistive track could be provided on particular sections of the inner wall, or the resistive track could be coated or printed onto the inner wall to cover a substantially full amount of the inner wall. The resistive track may follow a serpentine or sinuous path on the inner wall from a first end to a second end of the track. In other examples, the heater could comprise one or more resistive heating plates provided on the inner wall. The heating plate could also be provided as a sinuous or serpentine resistive track.
Preferably, the first connection pad is provided on the heater. In this way, the heater and connection pad can be electrically connected in a simple manner by attaching the connection pad to the inner wall over the heater, thus avoiding the need to electrically join or solder the first connection pad and the heater to one another.
In some embodiments, the first connection pad covers a substantially full amount of the heater. In this way, the connection pad can act as a protective layer over the heater that reduces the likelihood of damage to the heater. The first connection pad may fully cover the heater.
Preferably, the first connection pad has an electrical resistance that is less than the electrical resistance of the heater. More preferably, the first connection pad may have a resistance selected to generate a negligible amount of heat compared to the heater. In this way, the connection pad generates a substantially minimal amount of heat through conduction of electricity that could be lost from the insulator via the outer wall. Therefore, further energy loss is avoided and the device can be made more efficient.
Preferably, the heater and the first connection pad comprise different materials. In this way, the first connection pad can be optimised for mechanical robustness while the heater can be optimised for heating and efficiency.
Preferably, a second connection pad is provided on the inner wall, and the second connection pad is joined to the inner wall and the outer wall to seal the insulator. More preferably, the first connection pad and the second connection pad are connected to different parts of the heater and respectively configured to connect to opposite terminals of a power source to enable an electric current to flow through the heater. In this way, both of the necessary electrical connections to the heater can be made using connection pads rather than using sections of the heater, and the heating apparatus can be more robust. The second connection pad may be configured to seal the vacuum inside the vacuum insulator.
According to a second aspect of the invention, there is provided an aerosol generating device comprising the heating apparatus described above.
Preferably, the aerosol generating device comprises a controller configured to control operation of the heater, and the first connection pad is electrically coupled to the controller. In this way, the first connection pad acts to increase the robustness of the heating apparatus while also enabling the controller to control the heater. The first connection pad can be directly coupled to the controller or a circuit board, or coupled to the controller via one or more wires. In one example, a wire could be soldered to the first connection pad outside the insulator.
According to a third aspect of the invention, there is provided a method of manufacturing the heating apparatus as defined above, comprising the steps of: providing the heater on the inner wall; providing the first connection pad on the inner wall in electrical connection with the heater; joining the first connection pad to the inner wall and the outer wall; and covering the heater with the first connection pad at least partially to provide a protective layer over the heater.
Preferably, in embodiments where the heater comprises an electrically resistive track that is coated onto the inner wall, the step of providing the heater on the inner wall comprises coating the inner wall with an electrically resistive material.
Preferably, the step of joining the first connection pad to the inner wall and the outer wall comprises welding the outer wall to the inner wall and the first connection pad. Welding the outer wall to the inner wall and the first connection, rather than to the heater, avoids damage to the heater during the welding process. In other embodiments, the outer and inner wall could be joined using a heat resistant seal rather than welding.
Preferably, the welding comprises laser welding performed at least partially in a vacuum. In this way, a vacuum can be sealed inside the insulator during welding of the outer wall to the inner wall.
Embodiments of the invention are now described, by way of example, with reference to the drawings, in which:
The heating apparatus 100 comprises a cavity 110 that is provided adjacent the inner wall 104 and is configured to receive a consumable comprising a tobacco rod and a filter held together by a tipping wrapper.
The consumable can be inserted into the cavity 110 by a user via an opening 111 to the cavity 110 to be held in place by friction with the inner wall 104. A heater 112 is provided within the vacuum 108 and on an outer surface of the inner wall 104. The heater 112 is configured to be heated when an electrical current passes through it, and to pass this heat on to the inner wall 104 by conduction. Heat is then transferred through the inner wall 104 by conduction so that the inner surface of the inner wall 104 heats the consumable and the air inside the cavity 110. The heater 112 can be powered by a battery or any other power source provided on an aerosol generating device. The heater 112 comprises a first end 113a in electrical connection a first connection pad 114 and a second end 113b in electrical connection with a second connection pad 116. In the arrangement shown in
The vacuum insulator 102 is hollow and encloses a vacuum 108 between its curved inner wall 104 and its curved outer wall 106. The vacuum insulator 102 has a substantially cylindrical shape that enables the vacuum insulator 102 to surround the consumable fully. The vacuum insulator 102 provides thermal insulation so that the heater can heat an aerosol generating substrate effectively while not heating other portions of the aerosol generating device, especially portions of the aerosol generating device that are held by a user. The vacuum insulator 102 is elongate along its longitudinal axis, which enables it to receive a consumable in the form of an elongate rod comprising tobacco. The vacuum insulator 102 has an approximately elliptical or circular cross-sectional shape when viewed along one of its ends, parallel to its longitudinal axis; however in other embodiments the vacuum insulator 102 may have other types of cross sectional shape, for example shapes that are approximately square or polygonal.
The vacuum insulator 102 comprises an opening 111 for receiving the consumable at one longitudinal end and is closed at the opposite end. Thus, when viewed perpendicularly to its longitudinal axis as shown in
In other embodiments, the vacuum insulator 102 may instead be a non-vacuum insulator, i.e., an insulator containing an insulating medium such as air, fibrous or powdered insulators. The inner wall 104 and the outer wall 106 may be joined by the first connection pad 114 and the second connection pad 116 to seal the insulating medium between the inner and outer walls 104, 106.
The opening 111 is flared outwardly to enable a user to insert easily the consumable into the cavity 110. In other embodiments, the opening 111 may not be flared and the inner wall 104 may have a cross-section that is the same across the full longitudinal extent of the inner wall 104.
In the embodiment of
The outer wall 106 comprises stainless steel. In other embodiments, the outer wall 106 could comprise other suitable materials, such as other metals or plastics. The outer wall 106 comprises a single curved face that is substantially or wholly cylindrical. Other shapes of outer wall 106 could be implemented in accordance with alternatively shaped vacuum insulators.
The inner wall 104 has a thickness of about 0.1 millimetres (mm) or less. Having a relatively low thickness reduces the thermal mass of the vacuum insulator 102, and increases the rate of heat conduction through the inner wall 104 to the cavity 110 and the consumable. In particular, less heat is conducted away from the cavity 110 by the outer face of the inner wall 104. The threshold of 0.1 mm or less has been found to be significant in terms of improving the energy efficiency of the heating apparatus 100 by these mechanisms. In particular, an inner wall thickness of 0.1 mm has been found to have significantly improved thermal efficiency compared to an inner wall thickness of 0.25 mm.
The outer wall 106 has a thickness of about 0.25 mm, which may be preferable to a thickness of 0.1 mm to give the vacuum insulator 102 increased mechanical sturdiness and thermal insulation properties.
The cavity 110 is substantially cylindrical and is positioned immediately adjacent the inner wall 104. Preferably, the side of the inner wall 104 facing the cavity 110, i.e., the “inner surface” of the inner wall 104, is substantially or completely free of additional components so that the consumable can be in direct contact with the inner face when it is received in the cavity 110. This can maximise the efficiency of heat transfer from the inner wall 104 to the consumable. Further, the lack of additional components keeps the thermal mass of the heating apparatus low, which can improve the amount of time required to heat the tobacco to aerosol generating temperatures.
In the embodiment of
The heater 112 is printed or coated onto the outer face of the inner wall 104. In other embodiments, the heater 112 can comprise a heating element or plate provided on and attached to the inner wall 104. Thus, the heater 112 may provide “trace heating” to the cavity 110. The heater 112 may have a sinuous shape on the surface of the inner wall 104 so that a substantially full length of the inner wall 104 receives heating, as shown in
The heater 112 may comprise a material susceptible to an oxidation reaction in the presence of oxygen, and also may be provided without an anti-oxidation coating. Exposing the heater 112 to the vacuum 108 in this way takes advantage of the lack of oxygen in the vacuum insulator 102 to make the heater 112 cheaper and/or easier to manufacture.
The first connection pad 114 and the second connection pad 116 are provided as plates on the inner wall 104 and positioned on top of the heater 112 to enable an electrical connection between each of the connection pads and the heater 112. The first and second connection pads 114, 116 are spaced apart to prevent short circuiting and are provided at opposite ends of the track that forms the heater 112. The first and second connection pads 114, 116 are each sandwiched between, and joined to both of, the inner wall 104 and the outer wall 106. The first and second connection pads 114, 116 are curved to match the circumferential curvature of the inner wall 104.
In the embodiment of
Each of the first and second connection pads 114, 116 may extend through the join or seal between the inner and outer walls 104, 106 to enable an electrical connection to be made with the first and second connection pads 114, 116 outside of the vacuum insulator 102. The electrical connection could be made by wires soldered to the first and second connection pads 114, 116 that are configured to connect the heater 112 via the connection pads 114, 116 to a controller or battery provided in an aerosol generating device. In other embodiments, the connection pads 114, 116 may extend directly to the battery or controller when the heating apparatus 100 is provided within an aerosol generating device.
In the embodiment of
The heating apparatus 100 can be used with or provided in an aerosol generating device. The aerosol generating device would typically comprise a battery for powering the heater 112, a button or other input mechanism to enable a user to initiate the heater 112, and a controller to control the electronic components of the device, such as the heater 112. The heating apparatus 100 may be provided within a housing of the aerosol generating device, wherein the housing comprises an opening aligned with the opening 111 of the heating apparatus 100. The aerosol generating device may be configured as an electronic smoking device.
The heating apparatus 100 is configured to be used with a consumable comprising tobacco and a filter, which may be held together by a tipping wrapper. The consumable may be a cylindrical rod; however, other shapes of consumable designed to be received within the cavity 110 could also be used. Other forms of aerosol forming substance may be used alternatively or addition to tobacco.
Now, an example use of the heating apparatus 100, as used within an aerosol generating device, will now be described with reference to
In use, a user can insert the consumable through the opening 111 into the cavity 110. The consumable may have a diameter slightly less than the opening 111 to allow the consumable to be initially received in the cavity 110.
When the user is ready to initiate vaporisation, the user may press a button provided on the aerosol generating device, after which the controller may allow a current to flow from the battery to the heater 112 via the first connection pad 114 and the second connection pad 116. The heater 112 generates heat, due to its electrical resistance, that is transmitted to the inner wall 104 by conduction and radiation. The first connection pad 114 and the second connection pad 116 have low resistances and produce a negligible amount of heat due to the current flowing within. This minimises the amount of undesirable heating of the outer wall 106 to improve the efficiency of the heating apparatus 100.
While the heater 112 is operating, the vacuum 108 within the vacuum insulator 102 inhibits the conductive escape of heat from the cavity 110. The vacuum insulator 102 also prevents heat from escaping via convection, except from via the opening 111. In this way, the cavity 110, the heater 112, and the vacuum insulator 102 form a highly efficient heating oven in which the tobacco within the consumable can be heated to a desired aerosol generating temperature. The controller may be configured to instruct the heater 112 to heat the tobacco to temperatures below the combustion temperature of tobacco. It may take several seconds for the cavity 110 to reach aerosol generating temperatures.
The heater 112 is spaced apart from the outer wall 106 so that the heater 112 and the outer wall 106 are not in contact. This minimises the amount of heat transmitted to the outer wall 106 that is subsequently lost from the heating apparatus 100.
As the tobacco is heated, an aerosol is produced inside the cavity 110. The user can then inhale the aerosol by drawing air from the cavity 110 via the filter. This may draw air into the cavity 110 through a periphery of the opening 111 so that the user can continuously inhale aerosol from the cavity 110.
The heater 112 is difficult to repair due to its placement inside the vacuum insulator 102. Therefore, to avoid damage to the potentially fragile heater 112 during assembly or manufacture of the heating apparatus 100, the first connection pad 114 and the second connection pad are joined to the inner wall 104 and the outer wall 106 to seal the vacuum 108 inside the vacuum insulator 102. This avoids the need to join the outer wall 106 to the inner wall 104 over the heater 112, which can damage the heater 112. This arrangement may be especially effective when using a coated heating track, which can be particularly fragile.
The inner and outer walls 104, 106 can be welded to the first and second connection pads 114, 116. In one example, the inner and outer walls 104, 106 can be laser welded in a vacuum in order to create a vacuum inside the vacuum insulator 102. It is envisaged that other methods of joining the inner and outer walls 104, 106 to the first and second connection pads 114, 116 may be implemented.
Alternatively, a seal such as a rubber seal, may be provided to join the inner wall 104, the outer wall 106 and the first and second connection pads 114, 116.
In other embodiments, not shown in the Figures, the first connection pad 114 and the second connection pad 116 could be provided to cover a full or substantially full proportion of the heater 112. This can provide a protective layer for the whole heater 112 to prevent damage during use. In this case, parts of the heater 112 may be electrically insulated from the connection pads 114, 116 to avoid short circuiting.
A vacuum 208 is enclosed between the inner wall 204 and the outer wall 206, the cavity 210 is provided adjacent the inner wall 204, and a heater 212 is provided on the inner wall 204. A seal 118 is provided at the join between the inner wall 204 and the outer wall 206. Each of these components or aspects are configured in, and operate in, the same way as the corresponding features of the heating apparatus 100.
A first connection pad 214 and a second connection pad 216 are provided on the heater 212 at different ends of the heater track to facilitate a current flow through the heater 212, as described previously. The first connection pad 214 and the second connection pad 216 are curved at one end to match the circumferential curvature of the inner wall 204. These same ends are provided on the inner wall 204 in contact with the heater 212 to make an electrical connection with the heater 212, as shown in
In other respects, the first and second connection pads 214, 216 are configured in, and operate in, the same manner as the first and second connection pads 114, 116 as described above with reference to
| Number | Date | Country | Kind |
|---|---|---|---|
| 22154351.5 | Jan 2022 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/052173 | 1/30/2023 | WO |
