WO2025119924A1

WO2025119924A1 - Heating assembly for an aerosol generating device

Info

Publication number: WO2025119924A1
Application number: PCT/EP2024/084558
Authority: WO
Inventors: Matteo BRUNA
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2023-12-04
Filing date: 2024-12-03
Publication date: 2025-06-12
Anticipated expiration: 2026-06-04
Also published as: TW202527846A

Abstract

A heating assembly for an aerosol generating device is disclosed. The heating assembly (10, 110, 210) comprises: an outer tube (14, 114, 214) having a first end and a second end; an inner tube (12, 112, 212) having an opening (16, 116, 216) for receiving an aerosol forming substrate arranged at the first end of the outer tube, wherein a vacuum insulating space (24, 124, 224) is provided between the inner tube and the outer tube; a heating element (26, 126, 226) arranged on an outer facing surface (28, 128, 228) of the inner tube between the inner tube and the outer tube; and one or more pieces of getter material (30, 130, 138, 230) provided on the outer facing surface of the inner tube in the vacuum insulating space.

Description

HEATING ASSEMBLY FOR AN AEROSOL GENERATING DEVICE

FIELD OF THE INVENTION

The present invention relates to a heating assembly for an aerosol generating device and an aerosol generating device comprising a heating assembly. The disclosure is particularly applicable to a portable aerosol generating device, which may be self-contained. In particular, the invention relates to an aerosol generating device with a heating element disposed within a vacuum chamber.

BACKGROUND

It is a developing field of interest to produce electronic cigarettes that heat, but do not bum, a solid or semi-solid aerosol forming substrate which comprises tobacco. These devices typically receive a rod of tobacco in a heating chamber. The rod is heated to release aerosol which can be inhaled by a user. One issue in these devices is that the heater which supplies heat to the heating chamber can also undesirably heat the remainder of the device. In compact devices this can be disadvantageous because the temperature of the outer surfaces of the device, which are held by a user, can become unacceptably high. In order to mitigate these effects some aerosol generating devices have been provided with vacuum chambers that can space the heater from the outer surfaces. This can provide thermal separation between the heating chamber and the outer surfaces which are held by a user.

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, vacuum 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.

An object of the present invention is to further improve the heating efficiency and reduce undesired heat loss. SUMMARY OF INVENTION

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; an inner tube having an opening for receiving an aerosol forming substrate arranged at the first end of the outer tube, wherein a vacuum insulating space is provided between the inner tube and the outer tube; a heating element arranged on an outer facing surface of the inner tube between the inner tube and the outer tube; and one or more pieces of getter material provided on the outer facing surface of the inner tube in the vacuum insulating space.

In this way, the integrity and effectiveness of the vacuum between the inner and outer tube is improved. In known vacuum heating assemblies it has been found that the vacuum level in the insulating space, e.g. a static vacuum system, is susceptible to degradation, which can occur due to several factors, such as permeation, outgassing, leaks or contamination. In order to prevent or minimise such degradation of the vacuum, the present invention makes use of getter materials in the vacuum insulating space to absorb or react with any residual gases in the insulating space. Getter materials function by chemically reacting or absorb residual gases, including water vapour, hydrogen, oxygen and other reactive species, in a vacuum or low pressure systems. By providing an improved vacuum in the heating assembly, the overall efficiency of the heating element and the aerosol generating device is also improved, which leads to faster heating times and more effective and efficient use of the power (e.g. battery) of the device. An improved vacuum also advantageously means that heat from the heating assembly is more effectively prevented from transferring to an outer casing of the aerosol generation device.

During operation of the heating assembly, heat from the heating element will increase the reactivity of the getter material and allow it to react with any gases in the vacuum insulating space to help maintain the vacuum level and improve the performance of the heating element. The present invention improves the overall reliability of the heating assembly since the residual gases are prevented from reacting with other components in the system, such as the pressure-containing inner and outer tubes, the heating element, or any seals within the vacuum insulating space. As should be appreciated, any undesirable reactions with the residual gases with the heating assembly (e.g. with the wall material or heating element material) would be detrimental to the vacuum insulation and the performance and reliability of the heating element. Accordingly, providing one or more pieces of getter material on the outer facing surface of the inner tube, along with the heating element, ensures that the getter material is in close proximity or contact with the heating element to better protect the heating element from any undesirable reactions.

A plurality of getter material pieces may be arranged on top of one another, in laminar form. As an example, a plurality of layers of getter material may be in the form of strips that circumferentially coat the inner and/or outer tube within the vacuum insulating space. Each layer in the plurality of layers in strip form may be spaced apart at a predetermined distance, at regular or irregular intervals, according to design or manufacturing requirements. In another example, the one or more pieces of getter material may be in the form of a plug or three-dimensional structure that is inserted into the vacuum insulating space. The plug may be in the shape of a thick-walled cylinder, a ring, or another three-dimensional shape. For example, another three-dimensional shape may be a hexagonal nut shape to allow gases to further increase the surface area of getter material. The getter material may be a porous structure or a foam-like structure which allows gases to move through I or in and around the structure. Further shapes or arrangements of one or more pieces of getter material in a vacuum insulating space will be apparent to the skilled person.

The operating or working temperature of a getter material (i.e. the temperature or temperature range at which the getter material effective absorbs or reacts with residual gases in the vacuum insulating space) may depend on various factors, including the shape of the inner and/or outer tubes (and the vacuum insulating space formed within), the power dissipation of the outer and inner tubes, and the proximity of the getter material to the heating element. Typically the operating temperature range of a getter material may be between 150 °C to 500 °C. Getter materials are typically effective in the low to medium vacuum range, which is commonly referred to as the "rough vacuum" or "medium vacuum." This range typically spans from atmospheric pressure (760 Torr or 1 bar) down to approximately 10'³ Torr (0.1 Pa).

Preferably, the one or more pieces of getter material is provided on at least a portion of an inner facing surface of the outer tube. In this way, the one or more pieces may be optimally positioned in the vacuum insulating space. Some getter materials are more effective at absorbing residual gases at lower temperatures, and accordingly the one or more pieces of getter material may be arranged on the at least a portion of an inner facing surface of the outer tube (that is, in the vacuum insulating space) at a predetermined distance away from the heating element so as to not be overheated. The one or more pieces of getter material provided on the outer facing surface of the inner tube may comprise a first getter material and the one or more pieces of getter material provided on the inner facing surface of the outer tube may comprise a second getter material, where the first getter material is different to the second getter material.

Preferably, the one or more pieces of getter material fully covers the inner facing surface of the outer tube. In this way, a greater surface area of getter material is provided on the inner facing surface of the outer tube to absorb or react with any undesirable residual gases.

The one or more pieces of getter material is provided on the outer facing surface of the inner tube. In this way, getter material can also be provided on the inner tube of the heating chamber. Arranging getter material on the outer facing surface of the inner tube places the getter material in closer proximity to the heating element (which is also arranged on the same outer facing surface). Preferably, the one or more pieces of getter material on the outer facing surface of the inner tube at least partially covers the heating element. In this way, a portion of the one or more pieces of getter material may be arranged directly on top of heating element on the outer surface of the inner tube. As will be appreciated, covering the heating element with getter material may further prevent the heating element from undesirably coming into contact, and react, with any gases in the vacuum.

Preferably, the one or more pieces of getter material comprises at least one of the following: a barium-based getter alloy; a zirconium-based getter alloy; a titanium or titanium-based getter alloy; an indium or indium-based getter alloy; or an non- evaporable getter alloy. Different getter materials may operate effectively at different temperatures, and therefore one or more getter materials may be used to optimise the vacuum integrity and heating element performance of the present heating chamber. Non-evaporable getter materials may have a lower working temperature range, such as between 150 °C to 250 °C, which makes them advantageous in applications where higher temperatures may be detrimental or impractical. Different getter materials may be arranged on different surfaces in the vacuum insulating space.

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.

According to another aspect of the invention, there is provided a method of manufacturing a heating assembly for an aerosol generating device, the method comprising: providing an outer tube having a first end and a second end; providing an inner tube having an opening for receiving an aerosol forming substrate; arranging a heating element on an outer facing surface of the inner tube between the inner tube and the outer tube; providing one or more pieces of getter material; arranging the inner tube and the outer tube such that the opening is positioned at the first end of the outer tube and to provide an insulating space between the outer tube and the inner tube, wherein the one or more pieces of getter material is applied to at least an outer facing surface of the inner tube in the insulating space; and forming a vacuum in the insulating space. Preferably, the one or more pieces of getter material is applied to at least a portion of an inner facing surface of the outer tube. By applying getter material to the inner facing surface of the outer tube, the one or more pieces may be optimally positioned in the vacuum insulating space. Preferably, the one or more pieces of getter material is applied to fully cover the inner facing surface of the outer tube. In this way, a greater surface area of getter material may be effectively provided on the outer tube.

The one or more pieces of getter material is applied to at least an outer facing surface of the inner tube. In this way, the surface of the inner tube may also be utilised for arranging the one or more pieces of getter material to improve the integrity of the vacuum and performance of the heating element. Preferably, the one or more pieces of getter material is applied to the heater cup so as to at least partially cover the heating element.

Preferably the method further comprises activating the one or more pieces of getter material. In this way, the one or more pieces of getter material can be enabled or activated to effectively react or absorb the residual gases in the vacuum insulating space. The activation of the getter material may be performed during the manufacturing of the heating chamber. As will be appreciated by the skilled person, different types of getter materials may be activated in different ways. Preferably, activating the one or more pieces of getter material comprises heating the heating assembly to an activation temperature, preferably wherein the activation temperature is greater than an operating temperature of the heating assembly. In this way, thermally-activated getter materials, such as barium-based getter alloys, zirconium-based getter alloys, titanium getter alloys, indium getters and non-evaporable getters (typically composed of a combination of reactive metals such as zirconium, vanadium, and other elements).

The activation of the one or more pieces of getter material may comprise heating the inner and/or outer tube at temperatures in the order of 400 °C to 900 °C, depending on the type of getter material used. This heating causes the getter to release vapor and become chemically active and ready to react with residual gases during tube operation. During operation of the heating chamber in an aerosol generation device, the temperature of the getter material would typically experience operating temperatures (in the range of 150 °C to 500 °C) that are significantly lower than the temperature used for the initial activation process. During operation, vapours may be released from the one or more pieces of getter material in the operating temperature range which react with the residual gases inside the tube to help maintain the vacuum level and improve the heating element performance.

Preferably, activating the one or more pieces of getter material is performed while forming the vacuum. During the activation process, vapours may be released into the insulating space. To optimise the vacuum forming process, the activation of the one or more pieces of getter material may take place concurrently with the formation of the vacuum. Preferably, a pump may be utilised to form the vacuum.

BRIEF DESCRIPTION OF DRAWINGS

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

Figure 1 is a perspective view of an aerosol generating device comprising a heating assembly;

Figure 2 is a cross-sectional schematic view of a heating assembly;

Figure 3 is a cross-sectional schematic view of a heating assembly; and

Figure 4 is a cross-sectional schematic view of a heating assembly.

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.

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 assembly 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.

Figure 2 shows a schematic view of a heating assembly 10 having an inner tube 12 and an outer tube 14. The heating assembly 10 comprises an opening 16, defined by the inner tube 12, arranged at a first end of the heating assembly 10 through which an aerosol forming substance, or consumable, can be received in a cavity 18 of the heating assembly 10. In other words the opening 16 acts as the access point for insertion of a consumable into the heating assembly 10 in its constructed form.

The inner tube 12 comprises a metallic material, such as stainless steel, which has good thermal conduction properties. The inner tube 12 further comprises a base wall 20 to provide a closed end of the inner tube 12 such that the inner tube 12 forms a heater cup shape. In use, the base wall 20 acts to limit the depth of insertion of a consumable. The outer tube 14 also comprises a metallic material, such as steel or stainless steel, which is readily formed into a tube or cylindrical shape.

In this example, the inner tube 12 is positioned radially within the inner facing surface 22 of the outer tube 14 such that the inner and outer tubes would appear as concentric cylinders if viewed from above or below, i.e. parallel to a longitudinal axis of the inner and outer tubes will show the cup and tube as concentric circles (not shown). In alternative examples, the inner tube 12 and/or outer tube 14 may be formed in other types of cross-sectional shape, such as a square or polygonal.

A vacuum 24 is enclosed between the inner and outer tubes of the heating assembly 10. 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 inner tube 12 and the outer tube 14 may be a low vacuum, a medium vacuum, or a high vacuum.

A heating element 26 is provided on the outer facing surface 28 of the inner tube 12 (i.e. such that the heating element is provided in the vacuum 24). The heating element 26 is an electrically resistive track that may be printed or coated on the inner tube 12. The heating element 26 is provided circumferentially around the outer facing surface 28 of the inner tube 12 in the shape of a square wave, where the heater track can be followed up from the base wall 20 if the inner tube 12 toward the opening 16, where the heater track then turns round to continue back toward base wall 20 in a repeated fashion. The heating element 26 may be provided in other shapes or patterns as will be apparent to the skilled person. Alternatively, the heating element 26 may be layered on the inner tube 12.

A layer of getter material 30 is arranged on the inner facing surface 22 of the outer tube 14 within the vacuum 24 to maintain the integrity of the vacuum 24 and the effectiveness of the heating element 26 over the lifetime of the heating assembly 10. As explained above, getter material 30 works by absorbing or reacting with any residual gases that may be formed in (e.g. by outgassing) or be leaked into (e.g. by permeation) the vacuum space during the operational life of the heating assembly 10. The layer of getter material 30 is deposited circumferentially around the entire inner facing surface 22 of the outer tube 14 to maximise the surface area of getter material.

Electrical wires 32 connect the heating element 26 to a power source or a printed circuit board assembly, PCBA (not shown). The heating assembly 10 also optionally comprises a thermocouple or thermistor wire (not shown) which can be connected to the PCBA to monitor and/or control the temperature of the heating element 26. The electrical wires 32 and the thermocouple/thermistor wire are moulded into a base wall portion 34 for the outer tube 14. Other techniques (such as holes and suitable seals) may be used to pass the wires through the base wall portion 34 that will be apparent to the skilled person.

The heating assembly 10 further comprises a vacuum line 36 that is arranged in the base wall portion 34 which can be connected to a vacuum pump (not shown) to form the vacuum during the manufacturing of the heating assembly 10. In another example (not shown) the vacuum 24 may be formed between the inner tube 12 and the outer tube 14 by assembling the heating assembly in a vacuum or low pressure environment. Further methods of enclosing a vacuum in the heating assembly will be apparent to the skilled person.

Figure 3 shows schematic view of another heating assembly 110 having an inner tube 112 and an outer tube 114, between which a vacuum 124 is enclosed. The inner tube 112 defines an opening 116 through which a consumable, can be received in a cavity 118 of the heating assembly 110. The heating assembly 110 also comprises a heating element 126 arranged on the outer facing surface 128 of the inner tube 112, and electrical wires 132 connecting the heating element 126 to a power source.

Similar to the heating assembly 10 of Figure 2, a layer of getter material 130 is provided on the inner facing surface 122 of the outer tube 114 to react with any undesirable residual gases in the vacuum 124 during the operational life of the heating assembly 110. In this specific example in Figure 3, a plurality of layers of getter material 138 is also provided on the outer facing surface 128 of the inner tube 112. Advantageously, the plurality of layers of getter material 138 on the inner tube 112 can more readily capture I absorb heat from the heating element 126 during operation so as to bring the getter material to its optimum working temperature range (to absorb I react with residual gases).

The plurality of layers of getter material 138 are provided as strips of getter material that are positioned between the heater track of the heating element 126 (having a square wave shape on the inner tube 112). In this example, the getter material on the inner tube 112 is arranged as individual strips between the heater track of the heating element 126.

In an alternative example (not shown), getter material may be deposited on the inner tube 112 as a single layer which may at least partially cover (i.e. be arranged on top of) the heating element 126.

Figure 4 shows schematic view of another heating assembly 210 having an inner tube 212, an outer tube 214, and a vacuum 224 enclosed between the inner and outer tubes. The heating assembly 210 comprises an opening 216 at an end of the inner tube 212 through which a consumable can be received in a cavity 218 of the heating assembly 210. The heating assembly 210 also comprises a heating element 226 arranged on the outer facing surface 228 of the inner tube 212 and electrical wires 232 connecting the heating element 226 to a power source.

In this specific example in Figure 4, a plurality of pieces of getter material 230 is provided on the inner facing surface 222 of the outer tube 214 to react with any undesirable residual gases in the vacuum 224 during the operation of the heating assembly 210. The plurality of pieces of getter material 230 are provided as rings of getter material (e.g. a thick-walled cylindrical shape) that are inserted into space between the inner tube 212 and outer tube 214 circumferentially arranged around the inner facing surface 222 of the outer tube 214 toward a base wall portion 234 of the outer tube 214. In this example, the rings of getter material 230 are arranged in the vacuum 224 away from the heating element 226 to limit the degree of heating of the getter material when the heating element 226 is generating heat I in operation. The electrical wires 232 pass through the central holes (not shown) of the rings of getter material 230 to connect the heating element 226 to the power source.

An advantage of the example of Figure 4 is that the getter material is deposited in the vacuum 224 at a location in the heating assembly 210 that does not interfere with the heating element manufacturing process (i.e. away from the heating element 226 on the inner tube 212). As will be appreciated by the skilled person, the rings of getter material 230 are three-dimensional shapes and other three- dimensional structures or shapes may be used. The rings may be porous structures, like a foam, to allow gases to pass through the porous structure.

In this particular example, the getter material 230 is a non-evaporable getter material which has a low working temperature range (i.e. the temperature range at which the getter material optimally absorbs I reacts with residual gases). Accordingly, there is no getter material provided on the outer tube 214 adjacent to (in a transverse axis of the outer tube) the heating element 226 and there is no getter material provided on the inner tube 212.

As will be appreciated by the skilled person, different types of getter material and different shapes or structures of getter material may be deposited at different locations on the outer tube and/or inner tube according to different getter material properties (e.g. reactivity, working temperature range, etc.), design requirements, and/or manufacturing capabilities.

Claims

1 . A heating assembly for an aerosol generating device, comprising: an outer tube having a first end and a second end; an inner tube having an opening for receiving an aerosol forming substrate arranged at the first end of the outer tube, wherein a vacuum insulating space is provided between the inner tube and the outer tube; a heating element arranged on an outer facing surface of the inner tube between the inner tube and the outer tube; and one or more pieces of getter material provided on the outer facing surface of the inner tube in the vacuum insulating space.

2. The heating assembly of claim 1 , wherein the one or more pieces of getter material is provided on at least a portion of an inner facing surface of the outer tube.

3. The heating assembly of claim 2, wherein the one or more pieces of getter material fully covers the inner facing surface of the outer tube.

4. The heating assembly of claims 1 , 2 or 3, wherein the one or more pieces of getter material on the outer facing surface of the inner tube at least partially covers the heating element.

5. The heating assembly of any of claims 1 to 4, wherein the one or more pieces of getter material comprises at least one of the following: a barium-based getter alloy; a zirconium-based getter alloy; a titanium or titanium-based getter alloy; an indium or indium-based getter alloy; or an non-evaporable getter alloy.

6. 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 5; and a power source to provide electrical power to the heating element.

7. A method of manufacturing a heating assembly for an aerosol generating device, the method comprising: providing an outer tube having a first end and a second end; providing an inner tube having an opening for receiving an aerosol forming substrate; arranging a heating element on an outer facing surface of the inner tube between the inner tube and the outer tube; providing one or more pieces of getter material; arranging the inner tube and the outer tube such that the opening is positioned at the first end of the outer tube and to provide an insulating space between the outer tube and the inner tube, wherein the one or more pieces of getter material is applied to at least an outer facing surface of the inner tube in the insulating space; and forming a vacuum in the insulating space.

8. The method of claim 7, wherein the one or more pieces of getter material is applied to at least a portion of an inner facing surface of the outer tube.

9. The method of claim 8, wherein the one or more pieces of getter material is applied to fully cover the inner facing surface of the outer tube.

10. The method of claims 7, 8 or 9, wherein the one or more pieces of getter material is applied to the outer facing surface of the inner tube so as to at least partially cover the heating element.

11 . The method of any of claims 7 to 10 further comprising activating the one or more pieces of getter material.

12. The method of claim 11 , wherein activating the one or more pieces of getter material comprises heating the heating assembly to an activation temperature, preferably wherein the activation temperature is greater than an operating temperature of the heating assembly.

13. The method of claims 11 or 12, wherein activating the one or more pieces of getter material is performed while forming the vacuum.