Susceptor Assembly

The present disclosure relates to a susceptor assembly for an aerosol-generating system; a cartridge for an aerosol-generating system; an aerosol-generating system; and a method for manufacturing a susceptor assembly.

Aerosol-generating systems that employ inductive heating to heat an aerosol-forming substrate in order to generate an aerosol for user inhalation are generally known in the art. An aerosol-forming substrate is heated and vaporised to form a vapour. The vapour cools and condenses to form an aerosol, this aerosol is then inhaled by a user. Such electrically heated smoking systems are typically handheld and comprise a power supply, a reservoir for holding a supply of the aerosol-forming substrate and an inductive heating system.

Inductive heating systems typically comprise at least one inductor coil connected to the power supply. The inductive heating systems comprise a susceptor assembly comprising a susceptor element arranged in close proximity to the aerosol-forming substrate and within the alternating magnetic field. Some aerosol-generating systems comprise an aerosol-generating device and a cartridge that is configured to be used with the device. When the aerosol generating system comprises an aerosol-generating device and a cartridge, the susceptor element may form part of the cartridge.

The aerosol-forming substrate may be a liquid. In such cases, the aerosol-generating system may further comprise a wicking element configured to draw liquid aerosol-forming substrate from the storage portion to the susceptor element to be heated.

Typically, the susceptor assembly of inductive aerosol-generating systems may comprise a single wicking element comprising a single wicking layer.

It would be desirable to provide a susceptor assembly and an aerosol-generating system with more than one wicking layer, to improve delivery of liquid aerosol-forming substrate to the susceptor element and therefore enhance vaporisation of the liquid aerosol-forming substrate.

In accordance with a first embodiment of the present disclosure, there is provided a susceptor assembly for an aerosol-generating system. The susceptor assembly may comprise one or more wicking elements for transporting a liquid aerosol-forming substrate. The one or more wicking element may comprise a first wicking layer and a second wicking layer. The susceptor assembly may further comprise a spacer element positioned between and in contact with the first wicking layer and the second wicking layer. The susceptor assembly may further comprise a susceptor element in contact with at least a portion of the one or more wicking element.

Advantageously, providing a first wicking layer and a second wicking layer may improve ease of manufacturing a susceptor assembly for an aerosol-generating system, whilst transporting sufficient liquid aerosol-forming substrate for aerosolisation. However, it has been found that two wicking layers in contact with each other may lead to condensation becoming trapped between the two wicking layers. This may then cause a release of steam. The steam may cause deformation of the susceptor assembly. Deformation of the susceptor assembly may in turn lead to reduced contact between the susceptor element and the one or more wicking elements, leading to reduced or inefficient aerosolisation of the liquid aerosol-forming substrate. The present invention provides a spacer element positioned between and in contact with the first wicking layer and the second wicking layer. Advantageously, the spacer element may improve liquid flow between the first wicking layer and the second wicking layer. Furthermore, the spacer element may provide a space for steam to build up, before it escapes the susceptor assembly, therefore minimising deformation of the susceptor assembly.

The one or more wicking elements may be configured to transport liquid aerosol-forming substrate to the susceptor element. The susceptor element may be configured to heat and vaporise the liquid aerosol-forming substrate.

The susceptor element may comprises a first susceptor layer and a second susceptor layer. The first susceptor layer may be in contact with at least a portion of the first wicking layer, and the second susceptor layer may be in contact with at least a portion of the second wicking layer. This may advantageously mean that, in operation, the one or more wicking elements is heated from two sides. This may increase the amount aerosol-forming substrate that is vaporised in a given time compared to a susceptor assembly comprising only one susceptor layer.

A first side of the spacer element may be in contact with a first side of the first wicking layer and the first susceptor layer may be in contact with a second side of the first wicking layer, wherein the first side of the first wicking layer opposes the second side of the first wicking layer. A second side of the spacer element may be in contact with a first side of the second wicking layer and the second susceptor layer may be in contact with a second side of the second wicking layer, wherein the first side of the second wicking layer opposes the second side of the second wicking layer. The first side of the spacer element may oppose the second side of the spacer element. In this arrangement, the first susceptor layer and second susceptor layer may be spaced from each other. The first wicking layer may be configured to transport liquid aerosol-forming substrate to the first susceptor layer. The second wicking layer may be configured to transport liquid aerosol-forming substrate to the second susceptor layer. This may allow delivery of liquid aerosol-forming to be balanced between the first susceptor layer and the second susceptor layer.

The first susceptor layer and second susceptor layer may be planar. In this context, a planar susceptor layer is a susceptor layer having a substantially greater length and width than thickness. The length and width directions are orthogonal to one another and define a first plane. A planar susceptor layer may have two opposing major surfaces extending in planes parallel to the first plane. One or both major surfaces is advantageously flat. During use of the first susceptor layer and second susceptor layer in an aerosol-generating system, this may allow air to flow across a surface of both the first susceptor layer and second susceptor layer, enhancing the entrainment of vapourised aerosol-forming substrate. The first susceptor layer and second susceptor layer may be substantially parallel to one another. The first susceptor layer and the second susceptor layer may have a rectangular cross-section taken across the first plane.

The first susceptor layer and second susceptor layer may be separate components.

The first susceptor layer and the second susceptor layer may be integral with each other. Advantageously, this may simplify manufacturing of the susceptor assembly.

The susceptor element may comprise a connection section that connects the first susceptor layer to the second susceptor layer. The susceptor element may comprise three sections. The first section of the susceptor element may comprise the first susceptor layer. The second section of the susceptor element may comprise the second susceptor layer. The third section of the susceptor element may be the connection section joining the first susceptor layer to the second susceptor layer.

The connection section may be “U”-shaped or “V”-shaped. Advantageously, a susceptor element with a “U”-shaped or “V”-shaped connection section may hold the one or more wicking elements and spacer element together, in contact with each other, and the first and second wicking layers in contact with the first and second susceptor layers.

The susceptor element may be formed by bending or folding a single piece of susceptor material to form the first susceptor layer, the second susceptor layer and the connection section of the susceptor element. Advantageously, a susceptor element formed in this way may be simple to manufacture.

The first wicking layer and second wicking layer may be substantially planar. The first wicking layer and the second wicking layer of the susceptor assembly may be substantially parallel.

The first wicking layer and the second wicking layer may be integral with each other. The first wicking layer and the second wicking layer may be formed from a single piece of wicking material.

The first wicking layer and the second wicking layer may be separate components. Advantageously, the first wicking layer and the second wicking layer being separate components may prevent any bends or folds in the wicking layers that could compress the wicking layer and lead to suboptimal liquid transport.

The susceptor assembly may be substantially planar. The susceptor assembly may have a rectangular cross-section taken across the first plane.

The susceptor assembly may comprise a heating region and at least one mounting region. The heating region is a region of the susceptor assembly that is configured to be heated to a temperature required to vaporise the aerosol-forming substrate upon penetration by a suitable alternating magnetic field. The heating region of the susceptor assembly may comprise at least a portion of the first susceptor layer. The heating region of the susceptor assembly may comprise at least a portion of the second susceptor layer. Each of the first susceptor layer, second susceptor layer, first wicking layer, second wicking layer and the spacer element may comprise a heating region.

Each of the first wicking layer, second wicking layer and the spacer element may comprise a mounting region. The at least one mounting region may be in contact with a susceptor holder. Preferably, at portion of the at least one mounting region may extend into a liquid reservoir. In preferred embodiments, the heating region may be arranged outside of the liquid reservoir. Advantageously, arranging the susceptor element substantially outside of the liquid reservoir, and particularly arranging the heating region of the susceptor assembly outside of the liquid reservoir, may ensure that the aerosol-forming substrate is heated sufficiently to release the volatile compounds only after the aerosol-forming substrate has been transported outside of the liquid reservoir. This may facilitate release of the volatile compounds from the aerosol-generating system.

In preferred embodiments, the cross-sectional area of the one or more wicking elements and the cross-sectional area of the spacer element, taken across the first plane, is greater that the cross sectional area of the susceptor element taken across the first plane. The length of the first susceptor layer and the length of the second susceptor layer may be about equal to the length of the first wicking layer, the second wicking layer and the spacer element.

The width of the first susceptor layer and the second susceptor layer may smaller than the width of the of the first wicking layer, the second wicking layer and the spacer element. The width of the first susceptor layer and the second susceptor layer may be about 20 percent smaller than the width of the of the first wicking layer, the second wicking layer and the spacer element. The width of the first susceptor layer and second susceptor layer may be about equal to the width of the heating region of the of the first wicking layer, the second wicking layer and the spacer element. The first susceptor layer and the second susceptor layer may not comprise a mounting region.

The first susceptor layer and the second susceptor layer may comprise a mounting region.

The susceptor assembly may form a shape of a cross. The first susceptor layer, the second susceptor layer, the first wicking layer, the second wicking layer, and the spacer layer, may have a cross-shaped cross-section along the first plane. The susceptor assembly may comprise a pair of mounting regions and a heating region. The heating region may be substantially rectangular and located centrally on the susceptor assembly. The pair of mounting regions may be substantially rectangular regions located at the periphery of the heating region. The mounting regions may be located at opposite sides of the heating region. The mounting regions may be arranged at the same central position along the length of the heating region. Each of the pair of mounting regions may have a smaller surface area than the heating region.

The spacer element may be fluid permeable. As used herein, a “fluid permeable” element means an element that allows liquid or gas to permeate through it.

The spacer element may be substantially planar, having a substantially greater length and width than thickness. The length and width directions are orthogonal to one another and define a first plane of the spacer element. The first side of the spacer element and the second side of the spacer element may oppose each other and extend in planes parallel to the first plane of the susceptor element. The spacer element may be configured to allow liquid aerosol-forming to move between the first side of the spacer element and the second side of the spacer element. The spacer element may be configured to transport liquid aerosol-forming substrate between the first side of the spacer element and the second side of the spacer element.

In the thickness direction the spacer element is preferably at least partially uncovered. For example, the spacer element in the thickness direction may have at least one area that is not covered by another component. Therefore, at least one area of the spacer element in the thickness direction may be open to an airflow passage in which, during use, the susceptor assembly is placed. During use of the susceptor assembly, steam may build up within the spacer element. Advantageously, before the steam reaches a pressure that could lead to deformation of the susceptor assembly, the steam may escape from the at least partially uncovered area of the spacer element in the thickness direction.

The spacer element may be configured to allow liquid aerosol-forming substrate to move between the first wicking layer and the second wicking layer. In particular, liquid aerosol-forming substrate may move between the first wicking layer and the second wicking layer when the first wicking layer is in contact with the first side of the spacer element and the second wicking layer is in contact with the second side of the spacer element.

The first wicking layer may be in contact with a first side of the spacer element and the second wicking layer is in contact with a second side of the spacer element. The spacer element may separate the first wicking layer from the second wicking layer. Advantageously, the spacer element may prevent the first wicking layer from being in contact with the second wicking layer, and therefore provide a space for steam. The one or more wicking elements may comprise a capillary material. The first wicking layer may comprise a capillary material. The second wicking layer may comprise a capillary material. A capillary material is a material that is capable of transport of liquid from one end of the material to another by means of capillary action. The capillary material may have a fibrous or spongy structure. The capillary material preferably comprises a bundle of capillaries. For example, the capillary material may comprise a plurality of fibres or threads or other fine bore tubes. In some embodiments, the capillary material may comprise sponge-like or foam-like material. The structure of the capillary material may form a plurality of small bores or tubes, through which liquid aerosol-forming substrate can be transported by capillary action.

The one or more wicking elements may comprise or consist of an electrically insulating material. The one or more wicking elements may comprise a non-metallic material. Preferably, the one or more wicking elements may not heat up in a magnetic field. The one or more wicking element may comprise a hydrophilic material or an oleophilic material. This may advantageously encourage the transport of the aerosol-forming substrate through the one or more wicking elements. The one or more wicking elements may comprise or consist of a porous ceramic material.

The one or more wicking elements may comprise a non-metallic material. Examples of suitable materials for the one or more wicking elements are sponge or foam materials, ceramic- or graphite-based materials in the form of fibres or sintered powders, foamed metal or plastics materials, fibrous materials, for example made of spun or extruded fibres, such as glass fibre, cellulose acetate, polyester, or bonded polyolefin, polyethylene, terylene or polypropylene fibres, nylon fibres or ceramic. Suitable materials for the one or more wicking elements may comprise cellulosic materials, such as cotton or rayon.

The one or more wicking elements may preferably comprise cotton, rayon or glass fibre. The first wicking layer may preferably comprise of consist of cotton. The second wicking layer may preferably comprise or consist of cotton.

The first wicking layer may have a thickness of between 0.1 and 0.5 millimetres. Preferably, the first wicking layer may have a thickness between 0.2 millimetres. The second wicking layer may have a thickness of between 0.1 and 0.5 millimetres. Preferably, the second wicking layer may have a thickness between 0.2 millimetres.

The spacer element may comprise a porous material. The spacer element may comprise more pores than the one or more wicking elements. The spacer element may comprise larger pores than the one or more wicking elements. The spacer element may be more porous that the one or more wicking elements.

The spacer element may comprise a capillary material. The spacer element may comprise more small bores or tubes, through which liquid aerosol-forming substrate can be transported by capillary action, than the one or more wicking elements. The spacer element may comprise larger bores or tubes, through which liquid aerosol-forming substrate can be transported by capillary action, than the one or more wicking elements. In this way, the rate of transport of the liquid aerosol-forming substrate through the spacer element may be higher than the rate of transport of the liquid aerosol-forming substrate through the first wicking layer or the second wicking layer.

The spacer element may not comprise a capillary material.

The spacer element may comprise a mesh. As used herein the term “mesh” encompasses grids and arrays of filaments having spaces therebetween. The term mesh also includes woven and non-woven fabrics.

The spacer element may comprise or consist of an electrically insulating material. The spacer element may comprise a non-metallic material. Preferably, the spacer element may not heat up in a magnetic field.

The spacer element may preferably comprise or consist of cotton. The spacer element may comprise a plastics material. The spacer element may comprise a polyetheretherketone (PEEK) film. The spacer element may comprise a fibre sheet.

The spacer element may have a higher fluid permeability than the fluid permeability of the one or more wicking elements.

The spacer element may comprise an aperture configured to allow liquid aerosol-forming substrate to move between the first wicking layer and the second wicking layer. The spacer element may comprise a plurality of apertures configured to allow liquid aerosol-forming substrate to move between the first wicking layer and the second wicking layer.

The aperture or apertures may also be a hole, cut-out, or channel.

The aperture or apertures may be defined through the spacer element, between the first side of the spacer element and the second side of the spacer element. In this way liquid aerosol-forming substrate may pass through the aperture or apertures between the first side of the spacer element and the second side of the spacer element.

The aperture or apertures may have a circular cross-section. The aperture or apertures may have a diameter of at least 0.1 millimetres.

The aperture or apertures may have rectangular cross-section. The aperture or apertures may have a triangular cross-section. The aperture or apertures may have any suitable cross-section.

The aperture or apertures may be defined at an end of the spacer element. The aperture or apertures may be finger-like apertures, meaning the apertures may be defined by three sides.

The aperture or each of the plurality of apertures may have a cross-sectional area of at least 0.005 millimetres squared. The aperture or each of the plurality of apertures may have a cross-sectional area of at least 0.01 millimetres squared.