RU2828025C2 - Porous element for vapour supply system - Google Patents

Abstract

FIELD: vapour supply systems.

SUBSTANCE: porous element contains an elongated rod made of a porous ceramic material, having the first end surface, the second end surface and one or more side surfaces passing between the first and the second end surfaces and defining the length of the rod, a metal coating deposited on at least one side surface on the at least part of the length of the rod. A portion of each of these one or more side surfaces adjacent to the first end surface is uncoated, forming an uncoated end portion of the rod.

EFFECT: porous element can be used as a current collector for induction heating, while expanding the possibility of choosing the material of the support element for the porous element.

27 cl, 17 dwg

Description

Field of technology to which the invention relates

The invention relates to a porous element for a vapor supply system, as well as to an aerosol source, a cartomizer or cartridge, and to a vapor supply system containing such a porous element.

State of the art

Many electronic vapor delivery systems, such as e-cigarettes and other electronic nicotine delivery systems using vaporized liquids, consist of two main components or sections, namely a cartridge or cartomizer section and a control unit (battery section). The cartomizer typically includes a liquid reservoir and an atomizer for vaporizing the liquid. These parts may be collectively referred to as an aerosol source. The atomizer typically combines the functions of porosity or capillary action and heating to transport the liquid from the reservoir to the location where it is heated and vaporized. For example, the atomizer may be in the form of an electric heater, which is a resistive wire formed into a coil or other shape for resistive (Joule) heating, or a current collector for induction heating, and a porous element, such as a fibrous wick with capillary or absorbent capacity in close proximity to the heater, which absorbs the liquid from the reservoir and transports it to the heater. The control unit usually includes a battery to supply power to the system to operate. Power from the battery is used to activate a heater, which heats up and vaporizes a small amount of liquid drawn from a reservoir. The vaporized liquid is then inhaled by the user.

Alternative designs of elements suitable for use as sprayers are of interest.

Disclosure of invention

The first object of the invention is a porous element for a steam supply system, comprising: an elongated rod made of a porous ceramic material, having a first end surface, a second end surface and one or more side surfaces continuing between the first end surface and the second end surface and defining the length of the rod; and a metal coating applied to at least one side surface of the rod over at least part of its length.

A second object of the invention is an aerosol source for a vapor supply system, which is a porous element according to the first aspect, and a reservoir for storing an aerosol-forming substrate material that must be delivered to the porous element for evaporation.

A third object of the invention is a cartomizer for a vapor supply system comprising a porous element according to the first aspect or an aerosol source according to the second aspect.

A fourth object of the invention is a vapor supply system comprising a porous element according to the first object of the invention, an aerosol source according to the second object of the invention, or a cartomizer according to the third object of the invention.

Various embodiments of the invention will now be described in detail with reference to the drawings.

Brief description of the drawings

Fig. 1 schematically shows an example of the implementation of an electronic cigarette containing a cartomizer and a control unit, a sectional view;

Fig. 2 – a cartomizer according to the invention, a perspective view with spatial separation of parts;

Fig. 3 - the cartomizer shown in Fig. 2, assembled, perspective view with partial section;

Fig. 4 is another example of the implementation of a cartomizer according to the invention, a schematic sectional view;

Fig. 5 is a first example of the implementation of a steam supply system according to the invention using induction heating, a simplified schematic sectional view;

Fig. 6 is a second example of the implementation of a steam supply system according to the invention using induction heating, a simplified schematic sectional view;

Fig. 7 is an example of the implementation of an elongated rod suitable for use in a porous element according to the invention, a schematic side view;

Fig. 8 is another example of the embodiment of an elongated rod suitable for use in a porous element according to the invention, a perspective view;

Fig. 9 is another example of the embodiment of an elongated rod suitable for use in a porous element according to the invention, a perspective view;

Fig. 10 is an example of the implementation of a porous element according to the invention, perspective view;

Fig. 11 is another example of the implementation of a porous element according to the invention, a perspective view;

Fig. 12 is a graph of the dependence of the thickness of the metal coating of a porous element on the position along the length of the porous element, corresponding to the first thickness profile;

Fig. 13 is a graph of the dependence of the thickness of the metal coating of a porous element on the position along the length of the porous element, corresponding to the second thickness profile;

Fig. 14 is an example of the implementation of an aerosol source containing a porous element according to the invention, a schematic side view in section;

Fig. 15 is another example of the implementation of an aerosol source containing a porous element according to the invention, a schematic side view in section;

Fig. 16A is an alternative example of the implementation of a porous element, schematic side view;

Fig. 16B is a thickness profile of the metal coating of the porous element shown in Fig. 16A.

Implementation of the invention

In the following, certain embodiments of the invention are described. Some features of certain embodiments of the invention may be implemented in a conventional manner and, for the sake of brevity, they are not described in detail. Thus, it should be understood that features of the device elements discussed in this description that are not described in detail may be implemented in accordance with any conventional technology for implementing such elements.

As described above, the present invention relates to (but is not limited to) electronic aerosol or vapor supply systems, such as electronic cigarettes. In the following description, the terms "electronic cigarette" and "e-cigarette" may sometimes be used; however, it should be understood that these terms can be used interchangeably with an aerosol (vapor) supply system or device. The mentioned systems are designed to generate an inhalable aerosol by evaporating a substrate in the form of a liquid or gel, which may or may not contain nicotine. In addition, hybrid systems can comprise a substrate in the form of a liquid or gel plus a solid substrate, which is also heated. The solid substrate can be, for example, tobacco or other non-tobacco products, which may or may not contain nicotine. The term "aerosol-forming substrate material" as used herein is intended to refer to substrate materials that can form an aerosol either by exposure to heat or by some other means. The term "aerosol" can be used interchangeably with the term "vapor".

In the present description, the term "component" is used to indicate a part, section, unit, module, device, assembly, etc. for an electronic cigarette that contains several smaller parts or elements, often within an outer housing or wall. The electronic cigarette may be formed or made from one or more such components, and these components may be detachably connected to each other or may be permanently connected to each other during manufacture to form the entire electronic cigarette. The present invention is applicable to systems consisting of two components that can be detachably connected to each other, for example, a component carrying an aerosol-forming substrate material that holds a liquid or other aerosol-forming substrate material (a cartridge, cartomizer, or consumable), and a control unit having a battery for supplying electric power necessary for operating an element for generating vapor from a substrate material. As a specific example, the present description provides a cartomizer as an example of the execution of a portion or component carrying an aerosol-forming substrate material, but the invention is not limited to this and is applicable to any configuration of a portion or component carrying an aerosol-forming substrate material. In addition, such a component may include more or fewer parts than those contained in the examples provided.

The present invention particularly relates to vapor delivery systems and components thereof that utilize an aerosol-forming substrate material in the form of a liquid or gel contained in a reservoir, tank, container or other vessel included in the system. The system includes a device for delivering the substrate material from the reservoir to provide vapor/aerosol generation therefrom. The terms "liquid," "gel," "fluid," "source liquid," "source gel," "source liquid," and the like may be used interchangeably with the terms "aerosol-forming substrate material" and "substrate material" to designate an aerosol-forming substrate material that has a form that allows its storage and delivery.

In Fig. 1, for the purpose of demonstrating the relationships between the various parts of a typical system and explaining the general principles of operation, an exemplary embodiment of an aerosol/vapor delivery system, such as an electronic cigarette 10, is shown very schematically (not to scale). In this example, the electronic cigarette 10 has a generally elongated shape extending along a longitudinal axis indicated by a dotted line and includes two main components, namely a power or control component, section or unit 20 and a cartridge assembly or section 30 (sometimes referred to as a cartomizer or clearomizer) carrying an aerosol-forming substrate material and being a vapor generating component.

The cartomizer 30 includes a reservoir 3 containing a source liquid or other aerosol-forming substrate material containing a composition such as a liquid or gel from which an aerosol is to be generated, for example an aerosol containing nicotine. The source liquid may contain from 1 to 3% nicotine and 50% glycerol, the rest is water and propylene glycol in substantially equal proportions and, possibly, also other components such as flavorings. A source liquid that does not contain nicotine may also be used, for example, to deliver a flavoring. The composition may also include a solid substrate (not shown in the drawings), such as a portion of tobacco or another flavoring element, through which the vapor generated from the liquid passes. The reservoir 3 has the form of a storage tank, which is a container or repository in which the source liquid can be stored, so that the liquid can freely move and flow within this tank. For a disposable cartomizer, the reservoir 3 may be sealed during manufacture after filling so that it can be disposed of after the initial liquid has been used up, or it may have an inlet or other opening through which the user can add new initial liquid. The cartomizer 30 also comprises an electric heating element or heater 4 located outside the reservoir 3 for generating an aerosol by evaporating the initial liquid by heating. A liquid transfer or delivery device (liquid transfer element), such as a wick 6 or another porous element, may be used to supply the heater 4 with the initial liquid from the reservoir 3. The wick 6 may have one or more portions located within the reservoir 3 or otherwise be in fluid communication with the liquid in the reservoir 3 to be able to absorb the original liquid and transfer it by capillary action to other portions of the wick 6 that are adjacent to or in contact with the heater 4. In this way, the original liquid is heated and evaporated and then replaced by new original liquid from the reservoir, supplied to the heater 4 by the wick 6. The wick can be considered as a bridge, path or channel between the reservoir 3 and the heater 4 that delivers liquid from the reservoir to the heater. Terms such as channel, liquid channel, liquid transfer channel, liquid delivery channel, liquid transfer mechanism or element and liquid delivery mechanism or element may be used interchangeably to refer to the wick or the corresponding component or structure.

The combination of the heater and the wick (or similar element) is sometimes called an atomizer, and the reservoir with the source liquid and the atomizer together may be called the aerosol source. Other terminology may be used, for example, a liquid delivery unit or a liquid transfer unit, and in the present context these terms may be used interchangeably to refer to a vapor-generating element (vapor generator) plus a capillary or similar component or structure (a liquid transport element) that supplies or transfers liquid received from the reservoir to the vapor generator for generating vapor/aerosol. Designs are possible in which the components may be arranged differently than in the very schematic representation shown in Fig. 1. For example, the wick 6 may be a completely separate element from the heater 4, or the heater 4 may be porous and capable of performing, at least in part, a capillary absorption function (for example, in the form of a metal mesh). In an electrical or electronic device, the vapor generating element may be an electrical heating element operating on the principle of ohmic/resistive (Joule) heating or on the principle of induction heating. Thus, in general, the atomizer can be considered as one or more elements implementing the function of generating vapor or an evaporating element capable of generating vapor from a source liquid delivered to it, and a liquid transport or delivery element capable of delivering or transporting liquid from a reservoir or similar liquid storage to a vapor generator due to an absorbent action/capillary force. The atomizer is usually located in a cartomizer of the vapor generating system. In some designs, liquid can be supplied from the reservoir directly to the vapor generator without the need for a separate capillary element. Embodiments of the invention are applicable to all configurations that are consistent with the examples given in the present description.

As shown in Fig. 1, the cartomizer 30 also includes a mouthpiece or mouthpiece portion 35 with an air outlet through which the user can inhale the aerosol generated by the atomizer 4.

The power component or control unit 20 includes an element or battery 5 (hereinafter referred to as a battery, which may be rechargeable) for powering the electrical components of the electronic cigarette 10, in particular for operating the heater 4. In addition, there is a controller 28, such as a printed circuit board and/or another electronic circuit for general control of the electronic cigarette. The controller 28 controls the heater 4 using energy from the battery 5 when vapor is required, for example, in response to a signal from a pressure or air flow sensor (not shown), which detects inhalation through the system 10, during which air enters through one or more inlet openings 26 made in the wall of the control unit 20. When the heating element 4 is activated, it vaporizes the source liquid supplied from the reservoir 3 by the liquid delivery element 6 to form an aerosol, which is then inhaled by the user through an opening in the mouthpiece 35. The aerosol is transferred from the aerosol source to the mouthpiece 35 via one or more air channels (not shown) that connect the inlet 26 to the aerosol source and the outlet when the user inhales through the mouthpiece 35.

The control unit or power section 20 and the cartomizer or cartridge assembly 30 are separate connectable parts that can be separated from each other in a direction parallel to the longitudinal axis, as shown by the solid arrows in Fig. 1. The components 20 and 30 are connected when the device 10 is in use by cooperating engagement elements 21, 31 (for example, a screw or bayonet connection), which provide a mechanical and, in some cases, an electrical connection between the power section 20 and the cartridge assembly 30. Electrical communication is required if the heater 4 operates by ohmic heating, so that current can flow through the heater 4 when it is connected to the battery 5. In systems that use induction heating, galvanic communication may be absent if the cartomizer 30 does not have parts that require electrical energy. The inductor may be located in the power section 20 and supplied with energy from the battery 5, and the cartomizer 30 and the power section 20 are shaped such that when they are connected, the magnetic field generated by the inductor is properly applied to the heater 4 to generate a current in the material of the heater. The induction heating means are discussed in more detail below. The design shown in Fig. 1 is only an exemplary arrangement, and various parts and elements may be distributed differently between the power section 20 and the section 30 of the cartridge assembly, and other components and elements may be located in it. The two sections may be connected end to end in a longitudinal configuration, as shown in Fig. 1, or in another configuration, such as a parallel arrangement side by side. The system may or may not have a generally cylindrical shape and/or a generally elongated shape. Either section or both sections or both components may be disposable and replaced when exhausted (e.g. when the reservoir is empty or the battery is discharged) or adapted for multiple use, which is ensured by refilling the reservoir and charging the battery. In other examples, the system 10 may be unitary, in which the power section 20 and the cartomizer 30 are located in a single housing and cannot be separated. The invention is applicable to any of these configurations and to other configurations known to those skilled in the art.

Fig. 2 shows the parts assembled into a cartomizer according to one embodiment of the invention. The cartomizer 40 consists of only four parts, which can be assembled together by applying pressure or compression if they have the appropriate shape. Accordingly, the manufacture can be very simple and understandable.

The first part is a housing 42, which defines a reservoir for storing an aerosol-forming substrate material (hereinafter referred to as liquid for brevity). The housing 42 has a generally tubular shape, which in this example has a circular cross-section and contains a wall or walls, the shape of which determines various parts of the reservoir and other elements. The cylindrical outer side wall 44 is open at its lower end by an opening 46, through which the reservoir can be filled with liquid and to which other parts can be connected. It defines the outer volume or dimensions of the reservoir. The reference to elements or parts located outside the reservoir is intended to indicate that the part is outside or partially outside the area limited by the outer wall 44.

Inside the outer side wall 44, concentrically therewith, a cylindrical inner wall 48 is arranged. Such a design defines an annular volume 50 between the outer wall 44 and the inner wall 48, which is a space for holding liquid, i.e. a reservoir. The outer wall 44 and the inner wall 48 are connected (for example, by an upper wall or as a result of the convergence of the walls with each other) to close the upper edge of the volume 50 of the reservoir. The inner wall 48 is open at the lower end by an opening 52, and also at the upper end. The tubular inner space, limited by the inner wall, is a passage or channel 54 for the air flow, which in the assembled system carries the generated aerosol from the nebulizer to the outlet opening of the mouthpiece of the system for inhalation by the user. The opening 56 at the upper end of the inner wall 48 may be the outlet opening of the mouthpiece, or a separate mouthpiece having a channel connecting the opening 56 with the outlet opening of the mouthpiece may be attached to or around the body 42.

The housing 42 may be formed from a molded plastic material, such as by injection molding. In the example shown in Fig. 2, the housing is formed from a transparent material; this allows the user to monitor the level or amount of liquid in the reservoir 44. Alternatively, the housing may be completely opaque or opaque but with a transparent window through which the liquid level can be monitored. In some examples, the plastic material may be rigid.

The second part of the cartomizer 40 is a flow direction element 60, which in this example also has a circular cross-section, and its shape is adapted to interact with the lower end of the housing 42. The flow direction element 60 is essentially a plug and is designed to perform multiple functions. When it is inserted into the lower end of the housing 42, it connects to the opening 46 to close and seal the reservoir volume 50, and connects to the opening 52 to close and isolate the air flow channel 54 from the reservoir volume 50. In addition, the flow direction element 60 has at least one liquid channel passing through it, through which the liquid enters from the reservoir volume 50 into a space external to the reservoir, which is a chamber in which the vapor/aerosol is generated by heating the liquid. Also, the flow direction element 60 has at least one more aerosol flow channel passing through it, through which the generated aerosol is transferred from the space of the aerosol generation chamber 82 to the air flow channel 54 in the housing 42, so that the aerosol is delivered to the mouthpiece opening for inhalation by the user.

The flow direction element 60 may be made of a flexible elastic material, such as silicone, so that it can be easily engaged with the housing 46 by means of a friction fit. In addition, the flow direction element 60 has a socket or a formation of a similar shape (not shown) on its lower surface 62, opposite the upper surface or surfaces 64, which are engaged with the housing 42. The socket receives and supports the atomizer 70, which is the third part of the cartomizer 40.

The atomizer 70 has an elongated shape with a first end 72 and a second end 74 located at opposite ends of its elongated shape. In the assembled cartomizer, the atomizer is inserted with its first end 72 into the seat of the flow direction element 60 in the direction of the reservoir body 42. Thus, the first end 72 of the atomizer is supported by the flow direction element 60, and the atomizer 70 continues in the longitudinal direction outward from the reservoir substantially along the longitudinal axis determined by the parts of the body 42 of a concentric shape. The second end 74 of the atomizer 70 remains free, i.e. the atomizer 70 is mounted cantilevered, protruding outward from the outer boundaries of the reservoir. The atomizer 70 performs the functions of absorption and heating for generating an aerosol and contains an electric heater acting as an induction receiver, and a porous part made with the possibility of absorbing liquid from the reservoir and supplying it to the heater. Examples of the implementation of the atomizer 70 are described in more detail below.

The fourth part of the cartomizer 40 is a casing 80, in this example having a circular cross-section. It comprises a cylindrical side wall 81, which can be closed by a base wall to limit the central cavity of the aerosol generation chamber 82. The upper rim 84 of the side wall 81 around the opening 86 has a shape that ensures the engagement of the casing 80 with parts of mutually corresponding shapes on the flow direction element 60, so that the casing 80 can be connected to the element 60 after the insertion of the atomizer 70 into the seat of this element 60. Thus, the flow direction element 60 acts as a cover that closes the central cavity of the aerosol generation chamber 82, which forms an aerosol generation chamber in which the atomizer 70 is located. The opening 86 provides communication with the liquid channel and with the aerosol flow channel in the flow direction element 60, so that the liquid can be delivered to the atomizer, and the formed aerosol can be removed from the aerosol generation chamber. In order to allow air to flow through the aerosol generation chamber and through the atomizer 70 and collect the vapor so that it is entrained in the air flow to form an aerosol, the wall or walls 81 of the housing 80 have one or more openings or perforations that allow air to be drawn into the aerosol generation chamber when the user inhales through the opening of the mouthpiece of the cartomizer.

The casing 80 may be formed from a plastic material, for example by injection molding. It may be formed from a rigid material so that it can easily come into contact with the flow guide element by sliding the two parts toward each other.

As noted above, the flow direction element can be made of a flexible elastic material and can hold the parts connected to it, namely the housing 42, the atomizer 70 and the casing 80, by means of a friction fit. Since these parts can be more rigid, the elasticity of the flow direction element, allowing it to deform when pressed against these other parts, compensates for any minor errors in the dimensions of the manufactured parts. Thus, the flow direction element can compensate for manufacturing errors in all parts, while ensuring a high-quality assembly of the parts as a whole to form the cartomizer 40. Thus, the requirements for the accuracy of manufacturing the housing 42, the atomizer 70 and the housing 80 can be somewhat relaxed, which reduces production costs.

Fig. 3 shows the cartomizer according to Fig. 1 in the assembled state. It can be seen that the flow direction element 60 has a shape on its upper surfaces that allows it to cover the opening 52 formed by the lower edge of the inner wall 48 of the housing 42 of the reservoir, and a shape concentrically on the outside to interact with the opening 46 limited by the lower edge of the outer wall 44 of the housing 42, in order to seal both the space 50 of the reservoir and the channel 54 for the air flow.

The flow direction element 60 has a channel 63 for liquid, which allows the flow of liquid L from the volume 50 of the reservoir to enter through the flow direction element into the space 65 located under the flow direction element 60. In addition, there is a channel 66 for the flow of aerosol, which allows the flow of aerosol and air A to pass from the space 65 through the flow direction element 60 into the channel 54 for the air flow.

The casing 80 has a shape of an upper rim, allowing to interact with corresponding shaped parts on the lower surface of the flow direction element 60, in order to form an aerosol generation chamber 82 substantially outside the external dimensions of the volume 50 of the reservoir, located inside the housing 42. In this example, the casing 80 has an opening 87 at the upper end near the flow direction element 60. This coincides with the space 65, with which the channel 63 for liquid and the channel 66 for the flow of aerosol communicate, allowing liquid to enter the aerosol generation chamber 82, and the aerosol to exit this chamber 82 through the channels in the flow direction element 60.

In this example, the opening 87 also acts as a seat for mounting the first supported end 72 of the atomizer 70 (in the description of Fig. 2, the seat of the atomizer was mentioned as being formed in the flow direction element; any variant can be used). Thus, the liquid entering through the channel 63 is supplied directly to the first end 72 of the atomizer 70 for absorption and absorption, and air or aerosol can pass through the atomizer 70 and enter the channel 66 for the aerosol flow. The second end 74 of the atomizer 70 is removed from the space 50 of the reservoir and has no support inside the aerosolization chamber 82. Thus, the atomizer 70 is supported cantilevered.

The atomizer 70 is made in the form of a porous rod element, which acts as an absorbent component of the atomizer 70. In this example, the rod has a cylindrical shape. On one or more surfaces of at least the lower part of the atomizer near the second end 74, located in the aerosol generation chamber 82, a metal coating is applied (not shown in Fig. 3). The coating acts as a heating element of the atomizer 70, being a current collector for induction heating. Liquid entering the space 65 is sucked in due to the absorbency of the porous material of the atomizer 70 and is transferred downwards to the heating element. Heating by induction will be described below.

The example shown in Fig. 2 and 3 has parts with substantially circular symmetry in a plane orthogonal to the longitudinal dimension of the assembled cartomizer, therefore, no orientation of the parts in the planes in which they are connected together is required, which allows for easier manufacturing. The parts can be connected to each other in any orientation relative to the longitudinal axis, so there is no need to place the parts in a specific orientation before assembly. However, the symmetrical shape is not required, and the parts can have alternative shapes.

Fig. 4 shows a sectional view of another example of an assembled cartomizer, also comprising a reservoir body, a flow direction element, an atomizer and a housing. However, in this example, in a plane orthogonal to the longitudinal axis of the cartomizer 40, at least some of the parts are oval rather than circular in shape and are arranged in such a way as to have symmetry along the major and minor axes of the oval. The elements are mirror symmetrical with respect to both the major and minor axes of the oval. This means that, when assembled, the parts can have either of two orientations, rotated 180° relative to each other around the longitudinal axis. Again, assembly is simplified compared to the assembly of a system consisting of parts that do not have symmetry.

In this example, the housing 80 also comprises a side wall 81 which is formed in such a way that it has different cross-sections at different points along the longitudinal axis of the housing, and a base wall 83 which define a space which forms an aerosol generation chamber 82. Towards its upper end, the housing widens to a larger cross-section in order to provide space for accommodating the flow guiding element 60. The section of the housing 80 with a larger cross-section has, as a rule, an oval cross-section (Fig. 4 B), and the section with a narrower cross-section of the housing has a generally circular cross-section (Fig. 4 C). The upper rim 84 of the housing around the upper opening 86 has a shape which ensures engagement with a corresponding shape on the housing 42 of the reservoir. This shape and engagement are shown in Fig. 4 in a simplified form; in reality it will be more difficult to ensure a relatively air- and liquid-tight connection. The housing 80 has at least one opening 85, in this case in the wall 83 of the base, to allow air to enter the aerosol generation chamber during inhalation by the user.

In this example, the housing 42 of the reservoir has a different shape compared to the examples of Figs. 2 and 3. The outer wall 44 defines an internal space, which is divided into three regions by two inner walls 48. The regions are located next to each other. The central region between the two inner walls 48 is a volume 50 of the reservoir for holding liquid. This region is closed from above by the upper wall of the housing. An opening 46 in the base of the volume of the reservoir allows liquid to be supplied from the reservoir to the aerosol generation chamber 82. The two lateral regions between the outer wall 44 and the inner walls 48 are channels 54 for the air flow. Each of them has an opening 52 at the lower end for the entrance of the aerosol and an opening 56 of the mouthpiece at its upper end (a separate mouthpiece can be added to the outside of the housing 42 of the reservoir).

The flow direction element 60 (shaded for clarity) is engaged with the lower edge of the housing 42 by means of shaped sections for engaging with the openings 46 and 52 in the housing 42 for sealing the volume 50 of the reservoir and the air flow channels 54. The flow direction element 60 has a single centrally located channel 63 for liquid, aligned with the opening 46 in the reservoir, for transporting liquid L from the reservoir to the aerosol generation chamber 82. In addition, there are two channels 66 for the aerosol flow, each of which continues from the inlet opening of the aerosol generation chamber 82 to the inlet opening into the air flow channels 54, through which the air entering the aerosol generation chamber through the opening 83 and entraining the vapor in the aerosol generation chamber 82 passes into the channels 54 to the outlet openings 56 of the mouthpiece.

The atomizer 70 is mounted by inserting its first end 72 into the liquid channel 63 of the flow direction element 60. Thus, in this example, the liquid channel 63 acts as a seat for the console mounting of the atomizer 70. The first end 72 of the atomizer 70 is directly supplied with liquid entering the channel 63 from the reservoir 50, and the liquid is sucked in due to the capillary properties of the atomizer 70 and fed along the atomizer for heating by a heater (not shown) of the atomizer 70, which is located in the aerosol generation chamber 82.

Fig. 4 (A), (B) and (C) show cross-sections of the cartomizer 40 at corresponding positions along the longitudinal axis of the cartomizer 40.

Although the invention relates to atomizers in which heating is achieved by means of resistive heating, requiring electrical connections to the heating element for the passage of current, the design of the cartomizer is of particular importance for the use of induction heating. This is a process in which an electrically conductive element, usually made of metal, is heated by electromagnetic induction through eddy currents flowing in the element that generates the heat. The inductor (working coil) operates as an electromagnet when a high-frequency alternating current from a generator is passed through it, which leads to the creation of a magnetic field. When the conductive element is in the flow of the magnetic field, the field penetrates this element and induces eddy currents in it. These flow in the element and generate heat when overcoming the electrical resistance of the element due to Joule heating, in the same way as heat is generated in a resistive electric heating element when current is passed through it. An attractive feature of induction heating is the absence of the need for a galvanic connection to the electrically conductive element; instead, it requires that a sufficient magnetic flux density be created in the area occupied by the heating element. In vapor delivery systems where heat generation is required near the liquid, this is advantageous because more efficient separation of the liquid and the electrical current can be achieved. Assuming that there are no other components in the cartomizer that require electrical power, there is no need for any electrical connection from the cartomizer to the power section, and the cartomizer wall can provide a more reliable barrier to the liquid, reducing the likelihood of leakage.

Induction heating is effective for direct heating of an electrically conductive element as described above, but can also be used for indirect heating of a non-conductive element. In a vapor supply system, it is necessary to provide heat to a liquid in a porous capillary portion of an atomizer to cause evaporation. For indirect heating by induction, the electrically conductive element must be located near or in contact with the element to be heated and between the working coil and the element to be heated. The working coil heats the conductive element by induction heating, and the heat is transferred by thermal radiation or conduction to the non-conductive element. In such a device, the conductive element is called a current collector. Thus, in an atomizer, the heating component can be made of an electrically conductive material (usually metal), which is used as an induction current collector to transfer thermal energy to the porous portion of the atomizer.

In Fig. 5 a system for providing steam is shown in a simplified form, comprising a cartomizer 40 and a feed section 20 adapted for induction heating. The cartomizer 40 may be as shown in the examples of Figs. 2, 3 and 4 (although other designs are not excluded) and is shown in general terms only for the sake of simplicity. The cartomizer 40 comprises an atomizer 70 in which induction heating is provided, so that the heating function is provided by a current collector (not shown in the drawing). The atomizer 70 is located in the lower part of the cartomizer 40 and is surrounded by a casing 80, which not only defines the aerosol generation chamber, but also provides a certain degree of protection for the atomizer 70, which may be relatively vulnerable to damage due to its cantilever mounting. However, the console mounting of the atomizer 70 provides effective induction heating, since the atomizer 70 can be inserted into the interior of the coil 90, and, in particular, the reservoir is located at a distance from the interior of the coil 90. Accordingly, in the supply section 20 there is a recess 22, into which the casing 80 of the cartomizer 40 fits when it is connected to the supply section for use (by means of, for example, a friction fit, a clamping action, a screw thread or a magnetic latch). The inductor 90 is located in the supply section 20 so as to surround the recess 22, and the coil 90 has a longitudinal axis around which individual turns of the coil pass, and a length that substantially corresponds to the length of the current collector, so that the coil 90 and the current collector overlap when the cartomizer 40 and the supply section 20 are connected to each other. In other embodiments, the length of the coil may not correspond to the length of the current collector, for example, the length of the current collector may be shorter than the length of the coil, or the length of the current collector may be longer than the length of the coil. Thus, the current collector is in the magnetic field generated by the coil 90. If the mentioned elements are arranged so that the separation of the current collector and the surrounding coil is minimal, the magnetic flux penetrating the current collector will be higher, and the heating effect will become more significant. However, the separation is at least partially determined by the width of the aerosol generation chamber 82, the size of which must be such as to ensure adequate air flow around the atomizer and to exclude the capture of liquid droplets. These two requirements must be balanced with each other when determining the sizes and arrangement of the various elements.

The supply section 20 comprises a battery 5 for supplying the coil 90 with electric power of the appropriate alternating current frequency. Also included in the system is a controller 28 for controlling the supply of energy when steam generation is required and, possibly, for providing other functions for controlling the steam supply system that are not discussed here. The supply section may also include other elements that are not shown in the drawings and are not relevant to the present discussion.

Fig. 5 shows a linearly arranged system in which the feed section 20 and the cartomizer 40 are connected end to end to obtain the shape of a writing pen.

Fig. 6 shows a simplified alternative design in which the cartomizer 40 is a mouthpiece for a more box-like design in which the battery 5 is located in the power section 20 on one side of the cartomizer 40. Other embodiments are also possible.

The atomizer 70 is a porous element, the shape and size of which are determined by an elongated rod-shaped part (also referred to herein as an "elongated rod") made of a porous material, wherein the porous material is a ceramic material.

In Fig. 7 an elongated rod 80 is shown schematically. The terms "elongated rod part" and "elongated rod" are intended to mean that the rod 80 has a three-dimensional shape that continues along a central longitudinal axis A _R for a distance that defines a length of the rod 80 that is greater than or significantly greater than the dimensions of the rod 80 in directions orthogonal to the longitudinal axis. In other words, the transverse dimensions (which may be, depending on the shape, a width, span, depth, diameter, or major/minor axis) of the rod 80 are less than its length. For example, the length L _R and the width W _R (which may be a constant value along the entire length or an average value if the transverse dimensions vary along the length or the cross-section of the rod is not circular) may have a ratio in the range L _R : W _R = from 2:1 to 6:1, such as 3:1 or 5:1. For example, the length may not be chosen to be too large in comparison to the width, since otherwise it may prevent the liquid from entering the lower part of the rod in configurations where the atomizer is mounted in a cantilever manner, such as in Fig. 2-6, or in other devices where the liquid is supplied to one end of the rod. In addition, in such configurations the width should not be too large, since this will lead to an increase in the overall dimensions of the cartomizer and the housing, which will require a corresponding increase in the dimensions of the inductor. In one example, the length of the rod is 12 mm, and the width is 3 mm, which gives a ratio of L _R : W _R = 4: 1. In the example shown in Fig. 7, the rod has a constant width W _R , while the width does not change depending on the position along the longitudinal axis A _R , but this is not significant.

Fig. 8 shows in perspective an example of the embodiment of an elongated rod 80, which has a cylindrical shape and, therefore, a circular cross-section. The shape of the elongated rod 80 is determined by its outer surfaces, which is true for any shape of the cross-section. The rod 80 has a first end surface or end face 86 at the first end 82 of the rod 80 and an opposite second end surface or end face 88 at the second end 84 of the rod 80. The end surfaces 86, 88 are circular. Typically, the first end surface 86 and the second end surface 88 are flat and lie in planes substantially perpendicular to the longitudinal axis A _R of the rod 80, but these features are not essential. One or both end surfaces 86, 88 can be curved or have another shape, for example concave or convex. They can lie at an angle to the longitudinal axis A _R , and these two end surfaces 86, 88 can be parallel or not parallel to each other. For example, in a rod intended for cantilever mounting with a support at its first end, the first end surface can be concave or have a recess inside or another surface to direct the flow of liquid from the reservoir into the central part or core of the rod to improve the penetration of liquid into the porous structure of the rod material.

One or more side walls, side surfaces or side faces 90 extend between the first and second end surfaces 86, 88. The cylindrical rod 80 shown in Fig. 8 has only one curved side surface 90, which continuously extends along the perimeter of the rod 80. The cylindrical rod can be useful for efficient induction heating, since the rod can be located coaxially inside the cylindrical inductor to be uniformly distant from the coil on all sides to ensure uniform induction heating. However, other shapes are not excluded. For example, the cross-sectional shape (that is, the shape of the rod in a plane orthogonal to the longitudinal axis, which is also the shape of the end surfaces 86, 88, if the cross-sectional shape is unchanged) can be an oval, which also has only one solid and curved side surface. Alternatively, the rod may be a prism with end faces and cross-sections that are triangles, squares, rectangles, pentagons, hexagons, or higher order polygons. The polygon may be regular or irregular.

Fig. 9 shows an elongated rod with a hexagonal cross-section. Accordingly, the rod 80 has six lateral faces 90 adjacent to each other around the perimeter of the rod 80. Similarly, the rod of a triangular prism will have three adjacent lateral faces, a square or rectangular prism will have four adjacent lateral faces, a pentagonal prism will have five adjacent lateral faces, and so on.

The atomizer with a porous element will be described in more detail below for simplicity of description using a cylindrical rod as an example. However, all its features are equally applicable to rods of other shapes, i.e. if a cylindrical rod has only one side wall, this should be understood as also applying to rods with several side faces, so that references to a "side face" also include "side faces", and any rod has at least one side face, or one or more side faces.

The second feature of the porous element is a metallic coating that is applied to a portion of the outer surface of the elongated rod. In particular, the metallic coating is applied to at least a portion of the side surface (side face) or at least one of the side faces.

As a first example, a metal coating is applied for use as a current collector for induction heating. When the porous element is inside the working inductor, the temperature of the metal increases, which allows the thermal energy to be transferred to the liquid contained in the porous structure of the rod material to generate steam.

As shown in Fig. 10, the porous element (which in this case can be considered as a sprayer 70, since it comprises a porous/capillary element in combination with a heating element) is a cylindrical elongated rod 80 made of porous ceramics and a metal coating 92. The metal coating 92 is continuously applied around the side wall 90 of the rod 80 on a portion of the length of the side wall 90 that extends from the second end surface 88 and, therefore, at the second end 84 of the rod 80, but ends before reaching the first end 82 of the rod 80. Thus, the first end 82 is not covered with the metal coating 92. This arrangement is designed in such a way that when the porous element 70 is cantilevered by its first end, as shown in Fig. 2-6, the current collector formed by the metal coating is positioned in a suitable manner to be surrounded by an inductor, as shown in Fig. 5 and 6. The length L _M of the metal coating 92 along the length of the rod 80 can be substantially consistent with the length of the inductor or can differ, as described above. The purpose of leaving the first end 82 of the rod without a metal coating is to reduce, limit or avoid heating of the material of the rod 80 near the first end 82. This reduces the transfer of thermal energy of the liquid stored in the cartomizer reservoir, which contacts the first end surface 86 of the rod 80. In addition, this reduces any undesirable effects of increasing the temperature of the component used to hold the porous element 70, i.e. the flow direction element 60, into which the first end of the porous element is inserted. The requirements for the heat resistance of the support element can be reduced, so the choice of material for the support element is expanded.

The length L _u of the uncoated section at the first end 80, relative to the entire length L _R of the rod, may be in the range from 10 to 50%, for example from 10 to 30% or from 20 to 30% or from 10 to 20%.

In order to ensure efficient heat transfer from the metal coating to the porous ceramic, the metal coating can extend continuously around the perimeter of the surface of the rod 80, in other words, continuously around all side faces 90, in addition to continuously continuing in the longitudinal direction. This ensures the maximum surface area of the current collector and, therefore, the maximum heating effect. However, this is not essential, and the metal coating can be discontinuous around the perimeter and/or along the length, for example applied in stripes. This can be used, for example, to create an individual heating profile.

In addition, the metallic coating 92 can be applied to one or more side surfaces 90 (continuously or discontinuously) along the entire length of the rod 80, so that the first end 82 of the rod 80 has a metallic coating and does not remain uncoated. Any support element holding the first end 82 of the rod 80 must withstand the increase in temperature that will occur due to the transfer of heat from the part of the metallic coating that is affected by the magnetic field of the inductor (which therefore works as a current collector) to the part of the metallic coating outside the inductor and in contact with the support element.

It should be noted that in the example shown in Fig. 10, the first end surface 86 of the rod 80 is not covered with a metal layer 92. This allows the liquid to exit the reservoir. A partial metal coating of the end surface 86 is not excluded, but this reduces the rate of absorption of the liquid by the porous ceramic, and therefore can be considered undesirable. In other cases, this can be deliberately used to reduce the rate of absorption of the liquid. Depending on how the rod 80 is held, part of the side surfaces 90 can also contact the liquid in the reservoir and, therefore, can also affect the absorption of the liquid.

The metal coating may have one or more gaps, holes, perforations or openings. The gaps may regulate the suction of liquid in the case of a metal coating on the first end surface 86 or may regulate the thermal conductivity.

Fig. 11 shows a porous element 70, in which a metal coating 92 is applied to the entire length of the side surface 90 of the rod 80 from the first end 82 to the second end 84. A series of holes or windows 94 in the metal coating 92 are arranged in the form of a ring along the perimeter near the first end 82 in order to reduce heat transfer from the current-receiving portion of the metal coating 92 (near the second end 84, as well as in the central portion of the length of the rod 80) to the portion at the first end 82 where the rod 80 is held. In addition, holes 94 are present in the metal coating applied to the first end surface 86 in order to regulate the rate at which the liquid will be absorbed by the porous ceramic. Other options for the arrangement of holes or other breaks in the metal layer are not excluded.

In addition, the holes in the metal layer can be used in a broader sense along the entire length of the metal layer to facilitate the escape of vapor from the porous ceramic. However, this is not necessary. It has been found that a certain thickness of metal suitable for use as a current collector, which will be discussed below, using metal deposition methods, which will also be discussed below, can allow the escape of vapor from the porous ceramic even through a continuous metal layer, i.e. through a layer in which there are no holes intended for this. The mechanism for this is not entirely understood, but it is likely that on a microscopic scale the metal layer is formed with some internal discontinuities, perhaps due to the surface shape and features of the porous ceramic, which are sufficient for the passage of vapor.

In any configuration, the second end surface 88 may have a metal coating or may be uncoated. Such a coating is not necessary to serve as a current collector, since sufficient heating can be provided only by the metal on the side surface or surfaces. However, such a coating may be useful for retaining liquid in the porous ceramic material. This aspect of the metal layer will be discussed below.

For effective use as a current collector, the metal coating applied to one or more side surfaces over at least part of the length of the rod has a thickness of at least 1 μm, preferably at least 5 μm. Typically, the thickness should not exceed 20 μm. Accordingly, the metal layer of the current collector can have a thickness in the range of 5 to 20 μm, for example, 5 to 15 μm, or 7 to 15 μm, or 10 to 15 μm, or 7 to 12 μm, or 9 to 22 μm. A thicker coating provides a larger volume and, therefore, a larger mass of metal for induction heating, so that more thermal energy can be transferred for evaporation of the liquid absorbed by the porous ceramics. However, a similar degree of heating can be achieved using metal of different thicknesses due to the appropriate selection of the frequency of the alternating current intended for supplying to the inductor for creating an alternating magnetic field. A higher frequency can provide the same degree of heating in a thinner metal layer than a lower frequency used for a thicker metal layer. Accordingly, a higher induction frequency can be selected to reduce the amount of metal required. For example, a metal layer of 9 to 10 μm thickness has proven practical for use with an induction frequency in the range of 2 to 3 MHz.

The relationship between the heating efficiency and the thickness of the metal layer can be used to provide a varying heating profile along the length of the atomizer from a simple inductor that operates at a single fixed frequency to generate an alternating magnetic field of substantially the same strength and frequency at all locations. In other words, all parts of the metal layer in the inductor are exposed to the same magnetic field. In this case, if the metal layer on the side surface has a different thickness at different locations, then different temperatures can be achieved in different parts of the atomizer. This can be used to concentrate the heating effect in the area where it is most needed, such as the middle part and the unsupported second end of the rod, and, for example, to reduce or minimize the heating of the supported first end.

The magnetic field of the inductor tends to be weaker at the ends of the inductor and closer to its ends, so the thickness profile and the corresponding heating profile can be used to increase or enhance this effect by using a thicker metal layer on the central or intermediate portion of the atomizer to match the higher magnetic field strength created by the central portion of the inductor. Conversely, a thicker metal layer can be used to compensate for a weaker magnetic field. For example, a thicker metal layer can be applied to the second end of the rod to provide greater heating where the magnetic field strength may be weaker if the end of the inductor is aligned with or near the free end of the atomizer.

Fig. 12 shows a first example of a profile of the change in the thickness of the metal coating. The vertical axis shows the position along the length L _R of the rod, starting from 0 at the second end, so that higher values of L _R correspond to positions closer to the first end, namely to the end of the sprayer intended for its retention and for receiving liquid from the reservoir. The second end is a section of length L ₂ , the first end is a section of length L ₁ , and the intermediate part of the sprayer is the central section of length Lc. The thickness t of the metal coating and, accordingly, the temperature or heating effect T, which will be greater for a thicker layer of metal, are plotted along the horizontal axis.

The profile has a small value of thickness t at the first and second ends (thin metal coating) and a larger value of thickness t (thicker metal coating) at the intermediate part. Thus, the heating will be greater in the intermediate part of the atomizer. Reducing the heating of the first end can reduce or minimize the heat transfer to the support element in which the atomizer is mounted and / or the liquid stored in the reservoir. Reducing the heating at the second end can be advisable, for example, if the amount of liquid that reaches this part of the porous ceramic remote from the reservoir is relatively small, so that the generation of steam from the second end is less. Alternatively, the profile can have a zero value of thickness t at the first end, as shown by the dotted line in Fig. 12. This indicates that the first end is not coated with metal, as in the example of Fig. 10. In another embodiment, the thickness t can have different values at the first and second ends, wherein both values of thickness t are less than the thickness of the thicker metal layer in the central region.

Fig. 13 shows a second example of a profile of change in the thickness of a metal coating. This profile has a small (or zero) value of thickness t at the first end in order to minimize heat transfer to the support element of the sprayer and the reservoir, and a larger value of thickness t at the intermediate part and at the second end, coinciding with the magnetic field created by the inductor.

These profile examples have a smooth change in thickness t over the section L _R . However, this is not a requirement and the profile may instead be stepped between different thicknesses t. Other profile shapes are not excluded. Typically, the metal layer has a thickness profile that varies along the length of the rod to create a heating or temperature profile in induction heating that also varies along the length of the rod.

Within the profile, the thickness t varies from a maximum value t _max to a minimum value t _min . The thickness t may vary within the ranges discussed above, for example from 5 μm to 20 μm; this applies especially to that part or parts of the metal layer which are intended to be used as a current collector. Typically, this is the second end and the central part, or primarily the central part. As mentioned in connection with Fig. 12, the profile may include sections in which t _min is zero, i.e. where there is no metal coating and the current collector function is not ensured. This is especially true in relation to the first end.

Alternatively, the metallic coating may be applied in some areas so as to have a thickness value t _min that is greater than zero, but insufficient to provide a noticeable or useful function as a current collector in the sense that little or no heating will be provided in an alternating magnetic field. Thickness values of less than 5 μm may be used for this purpose. For example, t _min may be approximately 1 μm, or approximately 2 μm, or approximately 3 μm, or approximately 0.5 μm.

The purpose of this thinner metal coating is to provide a sealing effect to reduce or prevent liquid from leaking out of the porous ceramic. This helps to keep the liquid inside the atomizer to generate vapor and reduces the leakage of free liquid into the aerosol generation chamber. The metal coating provides a sealing effect on the outer surface of the porous ceramic rod so that the pores in the ceramic are closed and the liquid cannot escape or at least is hindered from escaping (although, as mentioned above, vapor can escape). The metal coating has also been found to have hydrophobic properties so that liquid is repelled from the surface of the rod.

Accordingly, some portions of the metal coating on the side surface or surfaces may have a thickness of less than 5 μm for the primary purpose of forming a sealing layer, and some portions of the metal coating on the side surface or surfaces may have a thickness of 5 μm or more, for example in the range of 5 μm to 20 μm, primarily to act as a current collector.

In addition, in this context, the second end surface can be provided with a metal coating of a thickness suitable for providing a sealing effect, i.e. less than 5 μm. This prevents leakage of liquid through the second end surface, which could otherwise be facilitated by the effect of gravity, since the second end of the rod will be the lowest part of the cantilever-mounted atomizer when the steam supply system, such as the examples described above, is in a typical and usual vertical orientation.

The sealing layer of the metallic coating may contain windows or openings for such purposes as reducing thermal conductivity and accelerating the escape of steam. If the openings are small in size, such that the surface tension effects of the liquid retained in the rod prevent the liquid from escaping through the openings, the presence of the openings need not be detrimental to the sealing effect.

It should be noted that although the porous element described herein has so far been considered to be intended for use as a cantilever mounted atomizer, this is not required and the porous element may be configured to be mounted in other configurations with a metal layer located in appropriate areas of the surface of the porous ceramic rod to act as a current collector and, in some cases, to provide some degree of sealing for leakage control.

In some examples, the porous element itself is not intended to be used as an atomizer, since the metal layer is not intended to perform the function of a current collector, and the rod of porous ceramic material is intended to be used as a porous absorbent component of the atomizer, in which the heater is a separate component located near the rod to transfer heat to the liquid absorbed by the ceramic material. In such a case, the metal coating applied to one or more surfaces of the porous ceramic rod is only a thin layer of less than 5 μm thick at all points. However, the thickness can vary depending on the position on the surface of the rod, for example, to be thicker in areas that are usually located lower when the porous element is installed in a steam supply system to counteract leakage caused by the downward movement of the liquid under the action of gravity. The metal layer configured in this way reduces leakage, i.e. provides the sealing effect described above, while ensuring easy release of steam from the ceramic material when the porous element is heated. However, some portion of the porous ceramic rod must remain open to allow liquid to penetrate the rod. This may be in the form of large uncoated areas, such as one or both end faces or end portions, and/or smaller windows or openings within the coated area.

Fig. 14 schematically shows an example of an embodiment of an aerosol source for a steam supply system, comprising a porous element configured in this way. The aerosol source is an annular reservoir 101 containing a liquid 102 to be evaporated. A central space inside the annular reservoir 101 defines an aerosol generation chamber 103 for generating steam in an air flow channel that passes through the entire steam supply system for passing air A to collect steam and deliver the aerosol for inhalation by the user to an outlet opening of the air flow channel (not shown in the drawing). The atomizer comprises an absorbent element 104 located inside the turns of a resistive electric heating element 105 made of a metal wire in the form of a coil. The absorbent element 104 is arranged across the air flow channel, and each of its two ends passes through openings in the inner wall 106 of the reservoir 101. The absorbent element 104 is a porous element comprising a rod 107 of porous ceramics with a metal coating 108 on its side surface, as described above. The metal coating 108 is applied only to the central part of the rod 107, and both end portions and the end surfaces of the rod 107 are not coated, therefore, these end portions can absorb liquid from the reservoir, and then the liquid is drawn through the porous structure by capillary action into the immediate vicinity of the heating element 105. When a current passes through the heating element 105, it heats up, so that the heat is transferred to the liquid in the porous ceramic, causing it to evaporate. The vapor can escape through the metal coating 108 and be captured by the air flow passing through the air flow channel. The metal coating acts as a sealing layer, reducing the likelihood of free liquid leakage from the absorbent element 104 into the aerosol generation chamber 103. The coating can have a thickness of less than 5 μm, such as 1 or 0.5 μm.

The configuration shown in Fig. 14 is only one example, and porous ceramic absorbent elements provided with metal coatings to reduce leakage can be used in other designs of the sprayer. For example, electrical heating elements or heaters configured differently than in the form of a coil or differently than placing an electrically conductive wire outside or inside the absorbent element can be used. The absorbent element and the reservoir can be located in a different spatial configuration so that the liquid is also absorbed by the absorbent element.

Alternatively, the metal coating can be used directly as a resistive heating element. This is compatible with a thin metal layer for sealing, since a smaller thickness provides a higher electrical resistance, so that resistive heating is more efficient. In addition, the total area of the metal coating can be selected taking into account the resistance, for example, by selecting the width of the ceramic rod and the length of the coated area. Typically, the metal thickness can be approximately 10 μm or less, and it can be useful if it is smaller, for example, 5 or 1 μm or less. In some cases, a thinner metal coating can be considered more suitable for increasing the electrical resistance. At one or at each end of the ceramic rod, there can be uncoated areas to allow liquid penetration. This can be a configuration such as that shown in Fig. 14, where the ends of the porous element enter the annular reservoir.

Fig. 15 schematically shows an example of an embodiment of an aerosol source for a steam supply system, which is a porous element having a metal layer configured to operate as a heating element for generating an aerosol. As in the example of Fig. 14, the porous (absorbing) element 104 is a rod 107 made of porous ceramics with a metal coating 108 on its side surface, as described above. The metal coating 108 is applied only to the central section of the rod 107, and both end sections of the rod 107 are not coated. The rod 107 is supported at the end sections so that its longitudinal axis is located across the aerosol generation chamber 103, i.e. across the direction of air flow A through the aerosol generation chamber 103, in order to collect steam and deliver the aerosol for inhalation by the user. As an example, a configuration is shown in which a support or fastening 112 supports each end section of the rod 107 without a coating, and each end section without a coating is similarly held from above by a fastening 114 that provides a supply of liquid. The fastenings 112, 114 can, for example, clamp the end sections together, or can be made in the form of a single component with an opening into which the end section of the rod 107 is inserted for holding it. Each of the liquid supply fastenings 114 has a channel 116 passing through it, which is connected at one end to a source of liquid or another aerosol-forming substrate (for example, to a reservoir, not shown in the drawing) and is open to the uncoated end sections of the rod at the second end by means of an outlet opening 115. In this way, the liquid L can be delivered to the porous material of the rod, where it is absorbed and transferred by absorbent or capillary action to the central section of the rod 107 with a metal coating 108.

In order for the metal coating 109 to function as a heating element, it is provided with an electrical contact or connection 109 at or near each of its edges (in other words, the contacts are spaced along the length of the rod 107), to each of which a conductive conductor or wire 110 is connected (for example by soldering), connected (directly or indirectly) to a power source, for example a battery (not shown). This arrangement allows an electric current to be passed through the resistive metal coating 109, so that the heat necessary for evaporating the liquid retained in the rod 107 is generated. In this example, the wires 110 pass inside the aerosol generation chamber 103, but as an alternative they can pass outside the aerosol generation chamber (outside the boundary formed by the fasteners 112), or can pass, for example, in channels inside the fasteners 114.

The arrangements shown in Figs. 14 and 15 are merely examples, and the various features of the invention may be implemented in various ways, as will be apparent to those skilled in the art. For example, the wire coil heater shown in Fig. 14 may be used together with the liquid supply device shown in Fig. 15, or the metal coating directly acting as a resistive heater, as shown in Fig. 15, may be used with the annular reservoir shown in Fig. 14. Other configurations of the liquid storage and flow means, as well as other devices for directly supplying electric current to the metal coating, are also possible and not excluded. In addition, for both direct and indirect resistive heating, the metal coating may be positioned on the porous rod differently than only on the central portion, as shown in Fig. 14 and 15. For example, a small uncoated area or an area containing small openings in the coating may be used to allow liquid to penetrate, instead of the completely uncoated ends shown in Figs. 14 and 15.

Fig. 16A schematically shows another example of the implementation of a porous element with a metal coating for use as a resistive electric heating element. The porous element, as before, is a rod 107 made of porous ceramics. In the central section L _c, the rod 107 is provided with a metal coating 108, typically having a thickness of 10 μm or less and intended to operate as a resistive electric heating element when an electric current is passed through it. In order to increase the length of the current path and to ensure heating over most of the length of the rod, this path is made in such a way that it passes along the rod 107. This can be achieved by making external electrical connections at two opposite ends of the rod. Two end sections of the rod 107, at section L ₁ at the first end 82 of the rod 107 and at a similar or equal section L ₂ at the second end 84 of the rod 107, are provided with a metal coating 108A of increased thickness. The increased thickness can be obtained by the same method that is used to apply the metal coating on the central section (for example, by the deposition method, which is discussed in more detail below). Alternatively, the metal coating of substantially the same thickness, corresponding to the desired thickness for the central section, can be applied over the entire or most of the full length of the rod 107, and another technology can be used to increase the coating thickness on the end sections 82, 84. Another metal can be used to coat the end sections, or the same metal can be used over the entire length of the rod.

The thicker areas are intended to act as electrical contacts for the thinner central metal coating and may facilitate the electrical connection with the central metal coating. For example, a soldered connection to a wire or terminal may be easier to make on a thicker metal layer. Alternatively, the rod may be mounted in a steam supply system such that a portion of the thicker metal areas come into contact with the conductive contacts, so that a physical connection is not required. This may allow the user, for example, to replace the rod when necessary. The contacts may be in the form of a fuse mount or a cylindrical battery mount, for example, using metal clips and/or offset elements to ensure close contact with the rod areas having a thick coating.

Fig. 16B shows a graph of the change in thickness t of the metal coating 108 along the length L _R of the rod. As can be seen, the end sections L ₁ and L ₂ have a significantly greater thickness of the metal coating than the central section L _c , which is made thin in order to provide high electrical resistance and, therefore, efficient electrical heating, as well as to provide an outlet for steam from the interior of the ceramic material. Although in this example the thickness profile is configured with step changes between thicker and thinner parts, this is not necessary, and a smoother change can be used if this is more suitable for the method of applying the metal coating, which is used to coat the porous element.

In the configuration shown in the example in Fig. 16A, it is necessary to leave one or more regions without coating to allow liquid to be absorbed by the ceramic material from an external source. It is useful that the end surfaces 86, 88 of the rod 107 can remain uncoated. Alternatively, one or more gaps can be left in the metal coating for liquid penetration either in the thicker end sections (electric contact sections) or in the thinner central section (electric heater section).

The metal layer can be applied to the surface of the porous ceramic using any of various deposition technologies that allow metals to be applied in layer thicknesses in accordance with the ranges described above. Examples of suitable technologies include physical vapor deposition, chemical vapor deposition and sputtering. Variations in thickness, uncoated areas and surfaces, and openings/windows/gaps can be achieved using known methods, such as masking and photolithography technologies. A person skilled in the art knows suitable methods for applying a micron-sized metal layer of constant or variable thickness to a portion or the entire surface of a portion of a porous ceramic material, including the above-mentioned and other technologies, such as any suitable lamination technology.

A variety of metals can be used for metallic plating. A useful example is nichrome, which is any alloy of nickel and chromium (and possibly other elements such as iron). It is a relatively inert metallic material, so it can withstand exposure to the liquid and steam in a steam generating system without degradation or interaction that could contaminate the steam. For example, an 80:20 nickel-chromium alloy can be used. Other examples include cobalt, nickel, and gold. However, metallic plating is not limited to these materials and can contain other metals, including elemental metals and alloys.

Various materials can be used as porous ceramics, such as aluminum oxide, cordierite, mullite, and silicon carbide. Aluminum oxide is the most suitable because it is a chemically neutral material. However, porous ceramics are not limited to the materials mentioned, and other materials can be used instead.

Various embodiments of the invention have been described above, by means of which it is possible to practically implement the invention and to provide inductors, induction devices, inductor assemblies, magnetic field generators, aerosol delivery devices and aerosol delivery systems of higher quality. The advantages and features of the embodiments of the invention are merely illustrative examples and are not exhaustive and/or exclusive. They are presented only to facilitate an understanding of the essence of the invention. It is understood that the advantages, embodiments, examples, functions, features, structures and/or other aspects should not be considered as limitations of the invention defined by its claims and that other embodiments can be used and modifications can be made without departing from the scope of the invention. The various embodiments of the invention may comprise, consist of or essentially consist of various combinations of the described elements, components, features, parts, steps, means, etc.

Claims (27)

1. A porous element for a steam supply system comprising an elongated rod made of a porous ceramic material having a first end surface, a second end surface and one or more side surfaces extending between the first and second end surfaces and defining the length of the rod; and a metal coating applied to at least one side surface over at least part of the length of the rod, wherein a portion of each of the one or more side surfaces adjacent to the first end surface does not have a metal coating, forming an uncoated end portion of the rod. 2. The porous element of claim 1, wherein the metal coating is applied to each of the one or more side surfaces. 3. The porous element of claim 2, wherein the metal coating extends continuously around one or more side surfaces. 4. The porous element according to claim 1, wherein the uncoated end portion occupies from 10 to 50% of the length of the rod. 5. A porous element according to any one of paragraphs 1-4, in which the metal coating is applied to one or more side surfaces up to the second end surface. 6. A porous element according to any one of paragraphs 1-5, in which the metallic coating is also applied to the second end surface. 7. A porous element according to any one of claims 1 to 6, wherein one or more side surfaces are a single side surface and the rod is a round or elliptical cylinder. 8. A porous element according to any one of claims 1 to 7, wherein the metal coating is applied by sputtering, chemical vapor deposition or physical vapor deposition. 9. A porous element according to any one of claims 1 to 8, wherein the metal is nickel, gold, cobalt or a chromium-nickel alloy. 10. A porous element according to any one of paragraphs 1-9, in which the thickness of the metal coating is from 1 to 50 μm. 11. The porous element of claim 10, wherein the thickness of at least part of the metal coating is less than 5 μm, forming a sealing layer on the rod to prevent liquid leakage. 12. A porous element according to any one of claims 10 or 11, wherein the thickness of at least part of the metal coating is less than 5 µm or more, forming a current collector for inductively heating the elongated rod. 13. A porous element according to claim 12, wherein the thickness of the metal coating is from 5 to 20 µm. 14. A porous element according to any one of claims 1 to 13, wherein the thickness of the metal coating varies depending on the position along the length of the rod. 15. The porous element of claim 14, wherein the thickness of the metal coating on at least one side surface has a first thickness near the first end surface and a second thickness near the second end surface, wherein the second thickness is greater than the first. 16. The porous element of claim 14, wherein the thickness of the metal coating on at least one side surface has a first thickness near the first end surface, a second thickness near the second end surface, and a third thickness at an intermediate section of at least one side surface, wherein the third thickness is greater than the first thickness and the second thickness. 17. A porous element according to any one of claims 15 or 16, wherein the greatest thickness of the metal coating is from 5 to 20 µm. 18. A porous element according to any one of claims 15 or 16, wherein at least the first thickness of the metal coating is less than 5 µm. 19. A porous element according to any one of claims 1-13, in which the metal coating is a current collector for inductively heating the elongated rod and is designed to provide a heating profile that varies along the length of the rod when used with an inductor operating with a spatially constant alternating current frequency. 20. The porous element of claim 10, further comprising electrical contacts for the metal coating that provide for the flow of electric current through the metal coating, so that the metal coating is a resistive electric heater for heating the elongated rod. 21. The porous element of claim 20, wherein the electrical contacts are a metal coating of greater thickness at or near the end sections of the elongated rod, and the thickness of the metal coating at the intermediate section of the elongated rod is less than said greater thickness, forming a resistive electric heater. 22. A porous element according to any one of paragraphs 20 or 21, in which the thickness of the metal coating performing the function of a resistive electric heater is no more than 10 µm. 23. A porous element according to any one of paragraphs 1-22, in which the metal coating has one or more openings, inside which the elongated rod has no coating. 24. An aerosol source for a vapor delivery system comprising a porous element according to any one of claims 1-23 and a reservoir for storing an aerosol-forming substrate to be delivered to the porous element for evaporation. 25. A cartomizer for a vapor delivery system comprising a porous element according to any one of claims 1-23 or an aerosol source according to claim 24. 26. A vapor supply system comprising a porous element according to any one of claims 1-23, an aerosol source according to claim 24 or a cartomizer according to claim 25, and an electrical power source. 27. The system according to item 26, designed with the possibility of supplying electrical energy from its source to the metal coating to ensure that it performs the function of a heating element.