HK40045887B

HK40045887B - An electrically heated smoking system with a capillary wick

Info

Publication number: HK40045887B
Application number: HK42021035924.6A
Authority: HK
Inventors: Olivier Yves Cochand; Flavien Dubief; Michel Thorens; Jean-Marc Flick
Original assignee: Philip Morris Products S.A.
Priority date: 2009-10-27
Filing date: 2021-08-02
Publication date: 2024-09-13

Description

The present invention relates to an electrically heated smoking system having a liquid storage portion.

WO 2007/078273 discloses an electrical smoking system which uses a liquid as an aerosol forming substrate. The liquid is stored in a container formed of a porous material. The container communicates with a heater vaporiser, powered by a battery supply, via a series of small apertures. In use, the heater is activated by the mouth of the user for switching on the battery power supply. Further, suction on the mouthpiece by the user causes air to be drawn through the porous container for liquid, over the heater vaporiser, and into the mouthpiece and subsequently into the mouth of a user.

EP 0845220 A1 discloses a flavour generation article having a casing constituted by first and second portions that are detachably connected to each other. A discharge port is arranged in a gas flow path, and in use a liquid material is supplied from the discharge port onto a ceramic heater disposed opposite to the discharge port.

The electrically heated smoking systems of the prior art, including that referred to above, do have a number of advantages, but there is still room for improvement. It is therefore an object of the invention to provide an improved smoking system.

According to the invention, there is provided an electrically heated smoking system according to claim 1 comprising: a capillary wick for holding liquid; at least one heater for heating the liquid in at least a portion of the capillary wick to form an aerosol; at least one air inlet, at least one air outlet and a chamber between the air inlet and air outlet, the air inlet, the air outlet and the chamber being arranged so as to define an air flow route from the air inlet to the air outlet via the capillary wick so as to convey the aerosol to the air outlet; and at least one guide for channeling the air flow in the air flow route, so as to control particle size in the aerosol. Even if the expression "smoking system" is sometimes used by default and by simplification, it is clear that the invention is implicitly directed to an electrically heated smoking system.

In use, when the heater is activated, the liquid in the at least one portion of the capillary wick is vaporized by the heater to form a supersaturated vapour. The supersaturated vapour is mixed with and carried in the air flow from the at least one air inlet. During the flow, the vapour condenses to form an aerosol in the chamber, and the aerosol is carried towards the air outlet into the mouth of a user. In this specification, the upstream and downstream relative positions are described in relation to the direction of air flow as it is drawn from the air inlet to the air outlet.

The smoking system according to the invention provides a number of advantages. Most significantly, the at least one guide improves the air and aerosol flow through the smoking system. In particular, the management of the air and aerosol flow through the smoking system by the guides allows either control of the air flow upstream of the capillary wick or control of the air and aerosol flow downstream of the capillary wick or both. The inventors have appreciated that management of the air flow, in particular the air flow direction and the air flow speed, allows the particle size in the resulting aerosol to be controlled and preferably reduced compared with known devices. This improves the smoking experience. Moreover, control of the air and aerosol flow can reduce the amount of liquid condensing on the inside surfaces of the smoking system. Such condensation may leak out of the smoking system and cause inconvenience for the user. Control of the air and aerosol flow can reduce such leakage. In addition, control of the air and aerosol flow can result in higher system efficiency and resulting energy savings.

The liquid has physical properties, for example a boiling point suitable for use in the smoking system: if the boiling point is too high, the at least one heater will not be able to vaporize liquid in the capillary wick, but, if the boiling point is too low, the liquid may vaporize even without the at least one heater being activated. The liquid preferably comprises a tobacco-containing material comprising volatile tobacco flavour compounds which are released from the liquid upon heating. Alternatively, or in addition, the liquid may comprise a non-tobacco material. The liquid may include water, solvents, ethanol, plant extracts and natural or artificial flavours. Preferably, the liquid further comprises an aerosol former. Examples of suitable aerosol formers are glycerine and propylene glycol.

The smoking system further comprises a liquid storage portion. The capillary wick is arranged to be in contact with liquid in the liquid storage portion. In that case, in use, liquid is transferred from the liquid storage portion towards the heater by capillary action in the capillary wick. In one embodiment, the capillary wick has a first end and a second end, the first end extending into the liquid storage portion for contact with liquid therein and the at least one heater being arranged to heat liquid in the second end. When the heater is activated, the liquid at the second end of the capillary wick is vaporized by the heater to form the supersaturated vapour.

An advantage of this embodiment is that the liquid in the liquid storage portion is protected from oxygen (because oxygen cannot generally enter the liquid storage portion via the capillary wick) and, in some embodiments light, so that the risk of degradation of the liquid is significantly reduced. Therefore, a high level of hygiene can be maintained. Using a capillary wick extending between the liquid and the heater, allows the structure of the system to be relatively simple. The liquid has physical properties, including viscosity, which allow the liquid to be transported through the capillary wick by capillary action.

The liquid storage portion is preferably a container. Preferably, the liquid storage portion does not include any porous materials, so that there is only a single capillary mechanism (the capillary wick) in the smoking system. This keeps the structure of the smoking system simple and the entire system low-maintenance. Preferably, the container is opaque, thereby limiting degradation of the liquid by light. The liquid storage portion may not be refillable. Thus, when the liquid in the liquid storage portion has been used up, the smoking system is replaced. Alternatively, the liquid storage portion may be refillable. In that case, the smoking system may be replaced after a certain number of refills of the liquid storage portion. Preferably, the liquid storage portion is arranged to hold liquid for a pre-determined number of puffs.

The capillary wick has a fibrous or spongy structure. For example, the capillary wick may comprise a plurality of fibres or threads. The fibres or threads may be generally aligned in the longitudinal direction of the smoking system. Alternatively, the capillary wick may comprise sponge-like material formed into a rod shape. The rod shape may extend along the longitudinal direction of the smoking system. The structure of the wick forms a plurality of small bores or tubes, through which the liquid can be transported to the heater, by capillary action. The capillary wick may comprise any suitable material or combination of materials. Examples of suitable materials are ceramic- or graphite-based materials in the form of fibres or sintered powders. The capillary wick may have any suitable capillarity and porosity so as to be used with different liquid physical properties such as density, viscosity, surface tension and vapour pressure. The capillary properties of the wick, combined with the properties of the liquid, ensure that the wick is always wet in the heating area. If the wick is dry, there may be overheating, which can lead to thermal degradation of liquid.

Preferably, the at least one guide channels the air flow by controlling the air flow velocity, that is to say, the speed of the air flow and the direction of the air flow. This may be by directing the air flow in a particular direction. Alternatively or additionally, this may be by controlling the speed of the air flow. The air flow speed may be controlled by varying the cross sectional area of the air flow route, so as to take advantage of the Venturi effect. Air flow through a constricted section increases in speed in order to satisfy the equation of continuity. Similarly, air flow through a wider section decreases in speed.

Preferably, the at least one guide is arranged so that the air flow speed over the wick is greater than the air flow speed upstream of the wick. The guides define a constricted air flow cross section over the wick, which will force the air flow to accelerate.

Preferably, the at least one guide is arranged to control the particle size of the aerosol to have a diameter substantially less than 1.5 micro meters (µm). Even more preferably, the at least one guide is arranged to control the particle size of the aerosol to have a diameter substantially less than 1.0 micro meters (µm).

The smoking system further comprises a housing and the at least one guide for channelling the air flow is provided by the internal shape of the housing. That is to say, the internal shape of the assembly itself channels the air flow. Preferably, the inside surface of the housing walls have a shape which forms guides to channel the air flow. The guides provided by the internal shape of the housing may be provided upstream of the capillary wick. In that case, the guides channel the air flow from the air inlet towards the capillary wick. Alternatively or additionally, the guides provided by the internal shape of the housing may be provided downstream of the capillary wick. In that case, the guides channel the aerosol and air flow from the capillary wick towards the air outlet. In a preferred embodiment, the internal shape of the housing defines a tapered channel towards the air outlet.

The internal shape of the housing may define a linear flow upstream or downstream of the capillary wick. The internal shape of the housing may define a swirled, that is to say, rotating or spiralling, flow upstream or downstream of the capillary wick. The internal shape of the housing may define any turbulent flow upstream or downstream of the capillary wick.

The smoking system comprises further a housing and the internal shape of the housing may at least partially define the shape of the chamber. The size and shape of the chamber affects the air and aerosol flow from the capillary wick towards the air outlet, which affects the process of aerosol formation. This affects the size of the particles in the aerosol. For example, if the chamber is small, this will encourage a fast movement of the aerosol particles towards the air outlet. On the other hand, if the chamber is larger, this may allow more time for the aerosol to form and flow towards the air outlet. The chamber may surround the capillary wick or may be downstream of the capillary wick. The position of the chamber relative to the capillary wick also affects the size of the particles in the aerosol. This is because this affects how quickly the vapour condenses to form the aerosol.

The smoking system comprises a housing and the housing is internally shaped downstream of the capillary wick to form an impactor for trapping larger aerosol particles. Larger aerosol particles may be those aerosol particles which have a diameter greater than about 1.5 micro meters. Alternatively, larger aerosol particles may be those aerosol particles which have a diameter greater than about 1.0 micro meters. Alternatively, larger aerosol particles may include those aerosol particles having another size. The greater inertia of the larger aerosol particles means that, if the air flow route includes a sudden change in direction, the larger aerosol particles may not be able to change direction sufficiently quickly to remain in the air flow route and may, instead, be trapped by the impactor. The impactor is preferably positioned to take advantage of the greater momentum of the larger aerosol particles.

The position of the impactor, for example relative to the capillary wick and heater and relative to the chamber, will affect the size and number of particles which are trapped. The smoking system comprises an impactor, the at least one guide may include an acceleration nozzle for directing the aerosol towards the impactor. The nozzle may define a decreasing cross sectional area of the air flow route, so as to accelerate the aerosol towards the impactor. Larger aerosol particles become trapped on the impactor, whereas the smaller aerosol particles can divert around the impactor in the flow route.

The at least one guide for channelling the air flow may be provided by one or more removable inserts contained in the housing. The one or more removable inserts may include a removable insert upstream of the capillary wick. The guides channel the air flow from the air inlet towards the capillary wick and heater. Alternatively or additionally, the one or more removable inserts may include a removable insert downstream of the capillary wick. In that case, the guides channel the aerosol and air flow from the capillary wick and heater towards the air outlet. The one or more removable inserts may channel the air flow directly on to the capillary wick and heater. The one or more removable inserts may channel the air flow directly off the capillary wick and heater.

The one or more removable inserts may define a linear flow upstream or downstream of the capillary wick and heater. The one or more removable inserts may define a swirled, that is to say, rotating or spiralling, flow upstream or downstream of the capillary wick. The one or more removable inserts may define any turbulent flow upstream or downstream of the capillary wick.

The one or more removable inserts may at least partially define the shape of the chamber. Usually, this will be in combination with the internal shape of the housing, but that is not necessarily the case. The size and shape of the chamber affects the air and aerosol flow from the capillary wick and heater towards the air outlet. This affects the size of the particles in the aerosol. The chamber may surround the capillary wick and heater or may be downstream of the capillary wick and heater. The position of the chamber relative to the capillary wick and heater also affects the size of the particles in the aerosol.

In a preferred embodiment, the one or more removable inserts includes a removable insert surrounding the capillary wick and heater. In that case, preferably the removable insert defines the flow route directly on to the capillary wick and heater and directly off the capillary wick and heater. In a first embodiment, the capillary wick is elongate and the removable insert directs the air flow on to the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick and directs the air flow off the capillary wick in a direction substantially parallel to the longitudinal axis of the capillary wick. Preferably, the smoking system comprises an elongate housing and the longitudinal axis of the capillary wick and the longitudinal axis of the housing are substantially parallel. In a second embodiment, the capillary wick is elongate and the removable insert directs the air flow on to the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick and directs the air flow off the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick. In that case, the air flow on to the capillary wick may be substantially perpendicular to the air flow off the capillary wick. Alternatively, the air flow on to the capillary wick may be substantially in the same direction as the air flow off the capillary wick. Again, preferably, the smoking system comprises an elongate housing and the longitudinal axis of the capillary wick and the longitudinal axis of the housing are substantially parallel.

Preferably, at least one of the removable inserts comprises bores for channelling the air flow therethrough. The bores may be formed in the insert by machining or, alternatively, by injection moulding.

In one embodiment, at least one of the removable inserts is downstream of the capillary wick and comprises an impactor for trapping larger aerosol particles. Larger aerosol particles may be those aerosol particles which have a diameter greater than about 1.5 micro meters. Alternatively, larger aerosol particles may be those aerosol particles which have a diameter greater than about 1.0 micro meters. Alternatively, larger aerosol particles may include those aerosol particles having another size. The greater inertia of the larger aerosol particles means that, if the air flow route includes a sudden change in direction, the larger aerosol particles may not be able to change direction sufficiently quickly to remain in the air flow route and may, instead, be trapped by the impactor. The impactor is preferably positioned to take advantage of the greater momentum of the larger aerosol particles.

For example, the removable insert may include a plate positioned downstream of the capillary wick for trapping larger aerosol particles which come into contact with the plate. The plate may be positioned substantially perpendicular to the air flow route. The position of the impactor, for example relative to the capillary wick and heater and relative to the chamber, will affect the size and number of particles which are trapped.

The smoking system comprises an impactor, the at least one guide may include an acceleration nozzle for directing the aerosol towards the impactor. The nozzle may define a decreasing cross sectional area of the air flow route, so as to accelerate the aerosol towards the impactor. Larger aerosol particles become trapped on the impactor, whereas the smaller aerosol particles can divert around the impactor in the flow route.

The one or more removable inserts may contain any of the liquid storage portion, the capillary wick and the heater. If a removable insert contains the liquid storage portion, the capillary wick and the heater, those parts of the smoking system may be removable from the housing as a single component. This may be useful for refilling or replacing the liquid storage portion, for example.

The guides may be provided by additional components positioned in the flow route. For example, the smoking system may further comprise pins, grills, perforated tubes, or any other component which may affect the flow route.

In one embodiment, the capillary wick is elongate and the guides are configured to channel the air flow upstream of the capillary wick in a direction substantially parallel to the longitudinal axis of the capillary wick. In that embodiment, the smoking system may be elongate in shape, with the longitudinal axis of the capillary wick being substantially parallel to the longitudinal axis of the smoking system.

In one embodiment, the capillary wick is elongate and the guides are configured to channel the air flow downstream of the capillary wick in a direction substantially parallel to the longitudinal axis of the capillary wick. In that embodiment, the smoking system may be elongate in shape, with the longitudinal axis of the capillary wick being substantially parallel to the longitudinal axis of the smoking system.

In one embodiment, the guides are configured to channel the air flow around the capillary wick in a spiral. In that case, the air may enter the spiral in a tangential direction. The air may exit the spiral in a tangential direction. In that embodiment, the capillary wick may be elongate in shape and the spiral may have an axis which is substantially the longitudinal axis of the capillary wick. The smoking system may be elongate in shape, with the longitudinal axis of the capillary wick being substantially parallel to the longitudinal axis of the smoking system.

In one embodiment, the capillary wick is elongate and the guides are configured to channel the air flow on to the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick. In that embodiment, the smoking system may be elongate in shape, with the longitudinal axis of the capillary wick being substantially parallel to the longitudinal axis of the smoking system.

Alternatively, the guides may be configured to channel the air flow onto the capillary wick in a direction intermediate between the direction of the longitudinal axis of the capillary wick and the direction perpendicular to the longitudinal axis of the capillary wick. That is to say, the guides may channel the air flow onto the capillary wick at a non-90° angle to the capillary wick, that is to say, in a diagonal direction.

In one embodiment, the capillary wick is elongate and the guides are configured to channel the air flow off the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick. In that embodiment, the smoking system may be elongate in shape, with the longitudinal axis of the capillary wick being substantially parallel to the longitudinal axis of the smoking system.

In one embodiment, the capillary wick is elongate and the guides are configured to channel the air flow off the capillary wick in a direction substantially parallel to the longitudinal axis of the capillary wick. In that embodiment, the smoking system may be elongate in shape, with the longitudinal axis of the capillary wick being substantially parallel to the longitudinal axis of the smoking system.

Alternatively, the guides may be configured to channel the air flow off the capillary wick in a direction intermediate between the direction of the longitudinal axis of the capillary wick and the direction perpendicular to the longitudinal axis of the capillary wick. That is to say, the guides may channel the air flow off the capillary wick at a non-90° angle to the capillary wick, that is to say, in a diagonal direction.

The at least one heater may comprise a single heating element. Alternatively, the at least one heater may comprise more than one heating element, for example two, three, four, five, six or more heating elements. The heating element or heating elements may be arranged appropriately so as to most effectively vaporize liquid in the capillary wick.

The at least one heater preferably comprises an electrical heating element. The at least one heater preferably comprises an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, Constantan, nickel-, cobalt-, chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetal^® and iron-manganese-aluminium based alloys. Timetal^® is a registered trade mark of Titanium Metals Corporation, 1999 Broadway Suite 4300, Denver Colorado. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. The at least one heater may take any suitable form. For example, the at least one heater may take the form of a heating blade. Alternatively, the at least one heater may take the form of a casing or substrate having different electro-conductive portions, or an electrically resistive metallic tube. Alternatively, the at least one heater may be a disk (end) heater or a combination of a disk heater with heating needles or rods. Alternatively, the at least one heater may take the form of a metallic etched foil insulated between two layers of an inert material. In that case, the inert material may comprise Kapton, all-polyimide or mica foil. Alternatively, the at least one heater may take the form of a sheet of material, which may be rolled around at least a portion of the capillary wick. Alternatively, the at least one heater may take the form of an etched foil folded around at least a portion of the capillary wick. The etched foil may comprise a metal sheet cut by a laser or by electro-chemical process. The sheet may be made from any suitable material, for example an iron-aluminium based alloy, an iron-manganese-aluminium base alloy or Timetal^®. The sheet may be rectangular in shape, or may have a patterned shape which may form a coil-like structure when rolled around the capillary wick. Other alternatives include a heating wire or filament, for example a Ni-Cr, platinum, tungsten or alloy wire.

The at least one heater comprises a coil of wire at least partially surrounding the capillary wick. In this embodiment, preferably the wire is a metal wire. Even more preferably, the wire is a metal alloy wire. The coil may extend fully or partially along the length of the capillary wick. The coil may extend fully or partially around the circumference of the capillary wick. In a preferred embodiment, the coil is not in contact with the capillary wick. This allows the heating coil to heat the capillary wick but reduces wastage by not vaporizing more liquid than necessary. This also reduces the amount of liquid which condenses on the inside walls, thereby reducing cleaning requirements.

The at least one heater may heat the liquid in the capillary wick by means of conduction. The heater may be at least partially in contact with the wick. Alternatively, heat from the heater may be conducted to the liquid by means of a heat conductive element. Alternatively, the at least one heater may transfer heat to the incoming ambient air that is drawn through the smoking system during use, which in turn heats the liquid by convection. The ambient air may be heated before passing through the system. Alternatively, the ambient air may be first drawn through the wick and then heated.

The smoking system is an electrically heated smoking system. The smoking system further comprises an electric power supply. Preferably, the electric power supply comprises a cell contained in a housing. The electric power supply may be a Lithium-ion battery or one of its variants, for example a Lithium-ion polymer battery. Alternatively, the power supply may be a Nickel-metal hydride battery, a Nickel cadmium battery, a Lithium-maganese battery, a Lithium-cobalt battery or a fuel cell. In that case, preferably, the electrically heated smoking system is usable by a smoker until the energy in the power cell is used up. Alternatively, the electric power supply may comprise circuitry chargeable by an external charging portion. In that case, preferably the circuitry, when charged, provides power for a pre-determined number of puffs, after which the circuitry must be re-connected to the external charging portion. An example of suitable circuitry is one or more capacitors or rechargeable batteries.

The smoking system further comprises electric circuitry. In one embodiment, the electric circuitry comprises a sensor to detect air flow indicative of a user taking a puff. The sensor may be an electro-mechanical device. Alternatively, the sensor may be any of: a mechanical device, an optical device, an opto-mechanical device, a micro electro mechanical systems (MEMS) based sensor and an acoustic sensor. In that case, preferably, the electric circuitry is arranged to provide an electric current pulse to the at least one heater when the sensor senses a user taking a puff. Preferably, the time-period of the electric current pulse is pre-set, depending on the amount of liquid desired to be vaporized. The electric circuitry is preferably programmable for this purpose.

Alternatively, the electric circuitry may comprise a manually operable switch for a user to initiate a puff. The time-period of the electric current pulse is preferably pre-set depending on the amount of liquid desired to be vaporized. The electric circuitry is preferably programmable for this purpose.

In one embodiment, the at least one air inlet comprises two air inlets. Alternatively, there may be three, four, five or more air inlets. Preferably, if there is more than one air inlet, the air inlets are spaced around the housing. In a preferred embodiment, the electric circuitry comprises a sensor to detect air flow indicative of a user taking a puff, and the at least one air inlet upstream of the sensor.

Preferably, the smoking system further comprises a puff indicator for indicating when the at least one heater is activated. In the embodiment in which the electric circuitry comprises a sensor to detect air flow indicative of a user taking a puff, the indicator may be activated when the sensor senses air flow indicative of the user taking a puff. In the embodiment in which the electric circuitry comprises a manually operable switch, the indicator may be activated by the switch.

The electrically heated smoking system may further comprise an atomiser including the at least one heater. In addition to a heating element, the atomiser may include one or more electromechanical elements such as piezoelectric elements. Additionally or alternatively, the atomiser may also include elements that use electrostatic, electromagnetic or pneumatic effects.

The smoking system comprises a housing. The housing comprises a shell and a mouthpiece. The electric power supply and the electric circuitry are contained in the shell. The liquid storage portion, the capillary wick, the at least one heater and the air outlet are contained in the mouthpiece. The at least one air inlet may be provided in either the shell or the mouthpiece. The guides may be provided in either the shell or the mouthpiece or both the shell and the mouthpiece. Preferably, the mouthpiece is replaceable. Having a shell and a separate mouthpiece provides a number of advantages. Firstly, if the replaceable mouthpiece contains the at least one heater, the liquid storage portion and the wick, all elements which are potentially in contact with the liquid are changed when the mouthpiece is replaced. There will be no cross-contamination in the shell between different mouthpieces, for example ones using different liquids. Also, if the mouthpiece is replaced at suitable intervals, there is little chance of the heater becoming clogged with liquid. Preferably, the shell and mouthpiece are arranged to releasably lock together when engaged.

The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK) and polyethylene. Preferably, the material is light and non-brittle.

Preferably, the smoking system is portable. The smoking system may have a size comparable to a conventional cigar or cigarette.

According to the invention, there is provided a smoking system comprising: a capillary wick for holding liquid; at least one air inlet, at least one air outlet and a chamber between the air inlet and air outlet, the air inlet, the air outlet and the chamber being arranged so as to define an air flow route from the air inlet to the air outlet via the capillary wick so as to convey aerosol formed from the liquid to the air outlet; and at least one guide for channelling the air flow in the air flow route, so as to control particle size in the aerosol.

In that case, the smoking system may comprise an atomiser to create the aerosol. The atomiser may include one or more electromechanical elements such as piezoelectric elements. Additionally or alternatively, the atomiser may also include elements that use electrostatic, electromagnetic or pneumatic effects.

Features described in relation to one aspect of the invention may also be applicable to another aspect of the invention.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows one example of a smoking system having a liquid storage portion;
Figures 2a, 2b and 2c show a first embodiment of the smoking system according to the invention;
Figures 3a and 3b show a second embodiment of the smoking system according to the invention;
Figures 4a and 4b show a third embodiment of the smoking system according to the invention;
Figure 5 shows a fourth embodiment of the smoking system according to the invention;
Figures 6a and 6b show a fifth embodiment of the smoking system according to the invention;
Figures 7a, 7b, 7c, 7d and 7e show a sixth embodiment of the smoking system according to the invention;
Figures 8a, 8b and 8c show a seventh embodiment of the smoking system according to the invention;
Figures 9a, 9b and 9c show an eighth embodiment of the smoking system according to the invention;
Figures 10a, 10b, 10c and 10d show a ninth embodiment of the smoking system according to the invention;
Figures 11a, 11b, 11c and 11d show a tenth embodiment of the smoking system according to the invention; and
Figures 12a to 12l show an eleventh embodiment of the smoking system according to the invention.

Figure 1 shows one example of a smoking system having a liquid storage portion. The smoking system 100 of Figure 1 is an electrically heated smoking system and comprises a housing 101 having a mouthpiece end 103 and a body end 105. In the body end, there is provided an electric power supply in the form of battery 107 and electric circuitry in the form of circuitry 109 and a puff detection system 111. In the mouthpiece end, there is provided a liquid storage portion in the form of cartridge 113 containing liquid 115, a capillary wick 117 and a heating element in the form of heating coil 119. One end of the capillary wick 117 extends into the cartridge 113 and the other end of the capillary wick 117 is surrounded by the heating coil 119. The heating coil is connected to the electric circuitry via connections 121. The housing 101 also includes an air inlet 123, an air outlet 125 at the mouthpiece end and a chamber in the form of aerosol forming chamber 127.

In use, operation is as follows. Liquid 115 is transferred by capillary action from the cartridge 113 from the end of the wick 117 which extends into the cartridge to the other end of the wick 117 which is surrounded by the heating coil. When a user draws on the device at the air outlet 125, ambient air is drawn through air inlet 123. In the Figure 1 arrangement, the puff detection system 111 senses the puff and activates the heating coil 119. The battery 107 supplies a pulse of energy to the heating coil 119 to heat the end of the wick 117 surrounded by the heating coil. The liquid in that end of the wick 117 is vaporized by the heating coil 119 to create a supersaturated vapour. At the same time, the liquid being vaporized is replaced by further liquid moving along the wick 117 by capillary action. (This is sometimes referred to as "pumping action".) The supersaturated vapour created is mixed with and carried in the air flow from the air inlet 123. In the aerosol forming chamber 127, the vapour condenses to form an inhalable aerosol, which is carried towards the outlet 125 and into the mouth of the user.

In the Figure 1 embodiment, the circuitry 109 and the puff detection system 111 are preferably programmable. The circuitry 109 and puff detection system 111 can be used to manage the device operation. This, in conjunction with the physical design of the electrically heated smoking system, can assist with control of the particle size in the aerosol.

The capillary wick can be made from a variety of porous or capillary materials and preferably has a known, pre-defined capillarity. Examples include ceramic- or graphite-based materials in the form of fibres or sintered powders. Wicks of different porosities can be used to accommodate different liquid physical properties such as density, viscosity, surface tension and vapour pressure. The wick must be suitable so that the required amount of liquid can be delivered to the heating coil.

Figure 1 shows one example of a smoking system which may be used with the present invention. Many other examples are usable with the invention, however. For example, the smoking system need not be electrically operated. For example, additional air inlets may be provided, for example, spaced circumferentially around the housing. For example, a puff detection system need not be provided. Instead, the system could operate by manual operation, for example, the user operating a switch when a puff is taken. For example, the housing could comprise a separable shell and mouthpiece. For example, the overall shape and size of the housing could be altered. For example, the liquid cartridge may be omitted and the capillary wick could simply be pre-loaded with liquid before use. Other variations are, of course, possible.

A number of embodiments of the invention will now be described, based on the example shown in Figure 1. Components shown in Figure 1 are not indicated again, in order to simplify the drawings. In addition, the puff detection system 111 and connections 121 are not shown, again for simplicity. Note that Figure 1 and the following Figures 2a to 11l are schematic in nature. In particular, the components shown are not to scale either individually or relative to one another.

Figures 2a, 2b and 2c show a first embodiment of the smoking system according to the invention. Figure 2a shows a cross sectional view of the mouthpiece end of the first embodiment of the smoking system 200. In Figure 2a, the smoking system 200 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided in removable insert 201 and in the housing inside walls 203. The air flow is shown by the dotted arrows.

The removable insert 201 extends across the entire cross section of the smoking system 200 and includes channels 205 for channelling the air flow between the air inlet and the capillary wick and heating coil. In this embodiment, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 201, although this need not be the case. The channels 205 taper inward to direct the air flow generally in the direction of the longitudinal axis of the housing but diagonally towards the capillary wick and heating coil.

In addition, the housing inside walls 203 are shaped to form the aerosol forming chamber 202 and provide guides for channelling the air and aerosol flow between the capillary wick and heating coil and the air outlet, through the aerosol forming chamber 202. In this embodiment, the housing inside walls 203 are tapered towards the air outlet and thereby direct the air and aerosol flow substantially in the direction of the longitudinal axis of the housing.

Figures 2b and 2c are cross sections along line A-A of Figure 2a. Figures 2b and 2c show two alternative arrangements for the channels 205 in removable insert 201. Although the cross section of the device is shown as circular in Figures 2a, 2b and 2c, this need not be the case. In Figure 2b, the inlet of each channel is circumferentially aligned with the outlet of the channel. In Figure 2c, the channels 205 are twisted around the axis of the housing. That is to say, the inlet of each channel is shifted circumferentially with respect to the outlet of the channel. Preferably, the insert 201 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example.

The embodiment shown in Figures 2a, 2b and 2c provides a substantially axially directed incoming air flow from the air inlet to the capillary wick and heating coil and a substantially axially directed outgoing air flow from the capillary wick and heating coil to the air outlet. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by insert 201 channel the air flow so as to concentrate air flow onto the wick and heating element and so as to increase turbulence. This decreases the particle size of the aerosol inhaled by a user. The guides provided by the housing inside walls 203 reduce the volume of the aerosol forming chamber 202 in the smoking system and therefore improve aerosol flow towards the air outlet. This improves the smoking experience. The arrangement of Figure 2c encourages a swirled airflow to improve aerosol formation even further.

A number of variations are possible in the smoking system of Figures 2a, 2b and 2c. Firstly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (insert 201, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing (shaped housing inside walls 203, as shown) or as a combination of both. Any number of channels 205 may be formed in the insert 201. The channels may be evenly or non-evenly distributed circumferentially around the insert. The channels may be arranged as several rows forming circles of different diameters. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels may be formed in the insert by machining. Alternatively, the insert may be formed together with the channels by injection moulding. The channels may be formed at any appropriate angle to the longitudinal axis of the housing. The housing inside walls 203 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber 202 within the smoking system.

Figures 3a and 3b show a second embodiment of the smoking system according to the invention. Figure 3a shows a cross sectional view of the mouthpiece end of the second embodiment of the smoking system 250. In Figure 3a, the smoking system 250 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided in removable insert 251 and in the housing inside walls 253. The air flow is shown by the dotted arrows.

The removable insert 251 extends across the entire cross section of the smoking system 250 and includes primary channels 255 and secondary channels 257 for channelling the air flow between the air inlet and the capillary wick and heating coil. In this embodiment, channels 255, 257 are substantially tubular bores in the insert 251. In this embodiment, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 251, although this need not be the case. Like channels 205 shown in Figures 2a, 2b and 2c, the primary channels 255 in Figures 3a and 3b taper inward to direct the air flow generally in the direction of the longitudinal axis of the housing but diagonally towards the capillary wick and heating coil. In Figures 3a and 3b, the secondary channels 257 extend generally parallel to the longitudinal axis of the housing. The secondary channels 257 are closer to the outside of the smoking system. This creates a secondary air flow which substantially bypasses the wick. This secondary airflow therefore carries fewer aerosol droplets than the air flow which is closer to the wick. This secondary, relatively dry, airflow close to the inside walls may reduce the amount of condensation forming on the inside walls. This may reduce leakage.

In addition, the housing inside walls 253 are shaped to form the aerosol forming chamber 252 and provide guides for channelling the air and aerosol flow between the capillary wick and heating coil and the air outlet, through the aerosol forming chamber 252. In this embodiment, the housing inside walls 253 are tapered towards the air outlet and thereby direct the air and aerosol flow substantially in the direction of the longitudinal axis of the housing.

Figure 3b is a cross section along line A"-A" of Figure 3a. Although the cross section of the device is shown as circular in Figures 3a and 3b, this need not be the case. Referring to Figure 3b, the insert 251 comprises primary channels 255 and secondary channels 257. In Figure 3b, the inlet of each primary channel 255 is circumferentially aligned with the outlet of the channel, as in Figure 2a. However, the primary channels 255 may be twisted around the axis of the housing, as in Figure 2b. In Figure 3b, the secondary channels 257 extend in the direction of the longitudinal axis of the housing. However, one or more of the secondary channels 257 may be angled to the longitudinal axis of the housing. The secondary channels 257 are closer to the housing than primary channels 255. Thus, the air flow through secondary channels 257 is towards the outside of the air flow through primary channels 255. In Figure 3b, the inlet of each secondary channel 257 is circumferentially aligned with the outlet of the channel. However, the secondary channels 257 may alternatively be twisted around the axis of the housing. Preferably, the insert 251 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example.

The embodiment shown in Figures 3a and 3b provides a substantially axially directed incoming air flow from the air inlet to the capillary wick and heating coil and a substantially axially directed outgoing air flow from the capillary wick and heating coil to the air outlet. In addition, the embodiment shown in Figures 3a and 3b provides an additional substantially axially directed incoming air flow from the air inlet to the capillary wick and heating coil and an additional substantially axially directed outgoing air flow from the capillary wick and heating coil to the air outlet. The additional airflow is towards the outside of the smoking system. Because the additional air flow is less close to the heating coil, it tends to carry less aerosol. Thus, it may contribute to improved aerosol characteristics and reduced condensation. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The guides provided by insert 251 channel the air flow so as to concentrate air flow onto the wick and heating element and so as to increase turbulence. This decreases the particle size of the aerosol inhaled by a user. They also provide an additional air flow which may reduce condensation forming in the smoking system. The guides provided by the housing inside walls 253 reduce the volume of the aerosol forming chamber 252 in the smoking system and therefore improve aerosol flow towards the air outlet. This improves the smoking experience.

A number of variations are possible in the smoking system of Figures 3a and 3b. Firstly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (insert 251, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing (shaped housing inside walls 253, as shown) or as a combination of both. Any number of channels 255, 257 may be formed in the insert 201. The channels may be evenly or non-evenly distributed circumferentially around the insert. The channels may be arranged as several rows forming circles of different diameters. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels may be formed in the insert by machining. Alternatively, the insert may be formed together with the channels by injection moulding. The channels may be formed at any appropriate angle to the longitudinal axis of the housing. The housing inside walls 253 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber 252 within the smoking system.

Figures 4a and 4b show a third embodiment of the smoking system according to the invention. Figure 4a shows a cross sectional view of the mouthpiece end of the second embodiment of the smoking system 300. In Figure 4a, the smoking system 300 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided in removable insert 301 and in the housing inside walls 303. The air flow is shown by the dotted arrows.

Just like removable insert 201 in Figures 2a, 2b and 2c, removable insert 301 extends across the entire cross section of the smoking system. However, in this embodiment, it also extends further upstream than the insert 201. The removable insert 301 includes channels 305 for channelling the air flow between the air inlet and the capillary wick and heating coil. The channels 305 extend in the direction of the longitudinal axis of the housing at their upstream end, then taper inward at their downstream end. The channels 305 direct the air flow generally in the direction of the longitudinal axis of the housing initially, then diagonally towards the capillary wick and heating coil. In this embodiment, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 301, although this need not be the case.

In addition, the housing inside walls 303 are shaped to form the aerosol forming chamber 302 and to provide guides for channelling the air and aerosol flow between the capillary wick and heating coil and the air outlet, through the aerosol forming chamber 302. In this embodiment, the housing inside walls 303 are tapered towards the air outlet and thereby direct the air and aerosol flow substantially in the direction of the longitudinal axis of the housing.

Figure 4b is a cross section along line B-B of Figure 4a. Although the cross section of the device is shown as circular in Figures 4a and 4b, this need not be the case. Referring to Figure 4b, the insert 301 comprises channels 305. Around the circumference of the insert 301 are several contact zones 307 for contacting with the inside of the housing. That is to say, the channels are formed by assembly of the insert in the housing. Preferably, the insert 301 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example.

The embodiment shown in Figures 4a and 4b provides a substantially axially directed incoming air flow from the air inlet to the capillary wick and heating coil and a substantially axially directed outgoing air flow from the capillary wick and heating coil to the air outlet. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by insert 301 channel the air flow so as to concentrate air flow onto the wick and heating element and so as to increase turbulence. This decreases the particle size of the aerosol inhaled by a user. The guides provided by the housing inside walls 303 reduce the volume of the aerosol forming chamber 302 in the smoking system and therefore improve aerosol flow towards the air outlet. This improves the smoking experience.

A number of variations are possible in the smoking system of Figures 4a and 4b. Firstly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (insert 301, as shown) or alternatively as an integral part of the assembly or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the assembly (shaped housing inside walls 303, as shown) or as a combination of both. Any number of channels 305 may be formed in the insert 301. The channels may be evenly or non-evenly distributed circumferentially around the insert. The channels may be arranged as several rows forming circles of different diameters. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels may be formed in the insert by machining. Alternatively, the insert may be formed together with the channels by injection moulding. The channels may be formed at any appropriate angle to the longitudinal axis of the housing. As in Figure 2c, the channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. The housing inside walls 303 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber 302 within the smoking system.

Figure 5 shows a fourth embodiment of the smoking system according to the invention. Figure 5 shows a cross sectional view of the mouthpiece end of the third embodiment of the smoking system 400. In Figure 5, the smoking system 400 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided by removable insert 401, by the housing inside walls 403 and by impactor 405. The air flow is shown by the dotted arrows.

The removable insert 401 is similar to removable insert 301 shown in Figures 4a and 4b. and extends across the entire cross section of the smoking system 400. The removable insert 401 includes channels 407 for channelling the air flow between the air inlet and the capillary wick and heating coil. The channels 407 extend in the direction of the longitudinal axis of the housing at their upstream end, then taper inward at their downstream end. The channels 407 direct the air flow generally in the direction of the longitudinal axis of the housing initially, then diagonally towards the capillary wick and heating coil. In this embodiment, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 401, although this need not be the case. Preferably, the insert 401 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example. The insert could alternatively take the form shown in Figure 2a or another suitable form.

In addition, the housing inside walls 403 and impactor 405 provide guides for channelling the aerosol flow between the capillary wick and heating coil and the air outlet. The housing inside walls 403 and impactor 405 also form the aerosol forming chamber 402. In this embodiment, the housing inside walls are shaped so as to direct the flow away from the heating coil in the radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing. The impactor 405 comprises a removable insert which may be positioned in the centre of the device, supported by the housing walls (see dotted lines). The impactor 405 allows larger aerosol particles to be trapped on its upstream side. This produces a filtering effect and reduces the average particle size. This is shown schematically in Figure 5. Then, the housing inside walls 403 and impactor 405 direct the air flow towards the air outlet.

The embodiment shown in Figure 5 provides a substantially axially directed incoming air flow from the air inlet to the capillary wick and heating coil and a substantially radially directed air flow downstream of the capillary wick and heating coil. It has been found that managing air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by insert 401 channel the air flow so as to concentrate air flow onto the wick and heating element and so as to increase turbulence. This decreases the particle size of the aerosol inhaled by a user. The guides provided by the housing inside walls 403 and impactor allow larger aerosol particles to be trapped and prevented from exiting through the air outlet. The arrangement allows the capillary wick and heating coil to be supplied with cool, non-saturated air, in order to decrease the aerosol particle size. This improves the smoking experience.

A number of variations are possible in the smoking system of Figure 5. Firstly, although the cross section of the device is shown as circular in Figure 5, this need not be the case. Secondly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (insert 401, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (shaped housing inside walls 403 combined with removable impactor 405, as shown). Any number of channels 407 may be formed in the insert 401. The channels may be evenly or non-evenly distributed circumferentially around the insert. The channels may be arranged as several rows forming circles of different diameters. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels may be formed in the insert by machining. Alternatively, the insert may be formed with the channels by injection moulding. The channels may be formed at any appropriate angle to the longitudinal axis of the housing. As in Figure 2c, the channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. The housing inside walls 403 and impactor 405 may be shaped and sized appropriately for the desired volume and shape of the aerosol forming chamber 402 within the smoking system. The impactor 405 may be formed with any appropriate shape and is preferably designed in conjunction with the shaped housing inside walls 403, in order to channel the air and aerosol flow as desired.

Figures 6a and 6b show a fifth embodiment of the smoking system according to the invention. Figure 6a shows a cross sectional view of the mouthpiece end of the fourth embodiment of the smoking system 500. In Figure 6a, the smoking system 500 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided by removable insert 501, by the housing inside walls 503 and by impactor 505.

The removable insert 501 is similar to removable insert 201 shown in Figures 2a, 2b and 2c and extends across the entire cross section of the smoking system 500 and includes channels 507 for channelling the air flow between the air inlet and the capillary wick and heating coil. In this embodiment, the liquid cartridge, the capillary wick and heating coil all form part of the removable insert 501, although this need not be the case. The channels 507 taper inward to direct the air flow generally in the direction of the longitudinal axis of the housing but diagonally towards the capillary wick and heating coil. Preferably, the insert 501 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example. The insert could alternatively take the form shown in Figures 4a and 5 or another suitable form.

In addition, the housing inside walls 503 are tapered inward to form the aerosol forming chamber 502. The housing inside walls 503 together with the impactor 505 provide guides for channelling the aerosol flow between the capillary wick and heating coil and the air outlet. In this embodiment, the housing inside walls 503 are shaped so as to form a nozzle to direct and accelerate the air flow substantially in the axial direction.

Impactor 505 is located directly downstream of the aerosol forming chamber. Figure 6b is a cross section along line C-C of Figure 6a. The impactor 505 acts to trap larger aerosol particles and therefore provide a filtering effect. The impactor 505 comprises a plate 505a which may be positioned in the centre of the housing, supported at the housing walls by struts 505b. The plate 505a acts to trap the larger aerosol particles exiting the aerosol forming chamber 502.

The embodiment shown in Figures 6a and 6b provides an accelerated, substantially axially directed air flow downstream of the capillary wick and heating coil. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by insert 501 channel the air flow so as to concentrate air flow onto the wick and heating element and so as to increase turbulence. This decreases the particle size of the aerosol inhaled by a user. The tapered nozzle shape provided by the housing inside walls 503 accelerate the aerosol downstream towards the impactor 505 and the plate 505a of the impactor 505 traps larger aerosol particles to prevent them exiting through the air outlet. The arrangement allows the capillary wick and heating coil to be supplied with cool, non-saturated air, in order to decrease the aerosol particle size. It also allows any larger aerosol particles that do form to be filtered out of the flow. This improves the smoking experience.

A number of variations are possible in the smoking system of Figures 6a and 6b. Firstly, although the cross section of the device is shown as circular in Figures 6a and 6b, this need not be the case. Secondly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (insert 501, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (shaped housing inside walls 503 combined with removable impactor 505, as shown). Any number of channels 507 may be formed in the insert 501. The channels may be evenly or non-evenly distributed circumferentially around the insert. The channels may be arranged as several rows forming circles of different diameters. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels 507 may be twisted around the axis of the housing to provide a swirled air flow. The channels may be formed in the insert by machining. Alternatively, the insert may be formed together with the channels by injection moulding. The channels may be formed at any appropriate angle to the longitudinal axis of the housing.

The housing inside walls 503 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber 502 within the smoking system and for the desired acceleration of the aerosol towards the impactor 505. The impactor may be formed by machining or injection moulding. The shape and size of the impactor plate 505a may be varied. The distance between the downstream end of the aerosol forming chamber 502 and the impactor plate may be varied.

Figures 7a to 7e show a sixth embodiment of the smoking system according to the invention. Figures 7a to 7e each show a cross sectional view of the mouthpiece end of the fifth embodiment of the smoking system. In each of Figures 7a to 7e, the smoking system includes guides for channelling the air flow within the smoking system. The air flow is shown by the dotted arrows.

Figure 7a shows a first arrangement of the smoking system 600. In Figure 7a, the guides are provided by removable insert 601 and by the housing inside walls 603. The removable insert 601 extends only across the centre of the smoking system 600, thereby directing the air flow between the air inlet and the capillary wick and heating coil to the outer circumference of the device. The removable insert 601 is shaped so that, at the capillary wick and heating coil, the air flow is directed onto the capillary wick and heating coil in a substantially radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing. In Figures 7a to 7e, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 601, although this need not be the case.

In addition, the housing inside walls 603 provide guides for channelling the air and aerosol flow between the capillary wick and heating coil and the air outlet. The housing inside walls 603 also define the aerosol forming chamber 602. In this embodiment, the housing inside walls 603 are shaped so as to direct the air and aerosol flow substantially in the direction of the longitudinal axis of the housing.

Figure 7b shows a second arrangement of the smoking system 600'. The arrangement shown in Figure 7b is identical to that shown in Figure 7a except that an additional insert 605 is provided in the smoking system 600' of Figure 7b. The additional insert 605 provides additional guides for directing air flow. The insert 605 is a ribbed insert surrounding the capillary wick and heating coil. It is shaped so as to direct the air flow onto the capillary wick and heating coil in a substantially radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing.

Figure 7c shows a third arrangement of the smoking system 600". The arrangement shown in Figure 7c is identical to that shown in Figure 7a except that an additional insert 607 is provided in the smoking system 600" of Figure 7c. The additional insert 607 provides additional guides for directing air flow. The insert 607 is a grill insert comprising a tube having a number of longitudinally spaced holes. The insert 607 surrounds the capillary wick and heating coil and directs the air flow through the holes in the grill and onto the capillary wick and heating coil in a substantially radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing.

Figure 7d shows a fourth arrangement of the smoking system 600‴. The arrangement shown in Figure 7d is identical to that shown in Figure 7a except that an additional insert 609 is provided in the smoking system 600‴ of Figure 7d. The additional insert 609 provides additional guides for directing air flow. The insert 609 is a grooved insert comprising a solid cylindrical tube having a number of channels formed in the radial direction. The insert 609 surrounds the capillary wick and heating coil and directs the air flow through the radial channels and onto the capillary wick and heating coil in a substantially radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing.

Figure 7e shows a fifth arrangement of the smoking system 600"". The arrangement shown in Figure 7e is identical to that shown in Figure 7a except that an additional insert 611 is provided in the smoking system 600ʺʺ of Figure 7e. The additional insert 611 provides additional guides for directing air flow. The insert 611 is a grooved insert comprising a solid conical tube having a number of channels formed in the radial direction. The insert 611 surrounds the capillary wick and heating coil and directs the air flow through the radial channels and onto the capillary wick and heating coil in a substantially radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing.

The embodiments shown in Figure 7a to 7e provide a substantially radially directed air flow onto the capillary wick and heating coil and a substantially axially directed air and aerosol flow downstream of the capillary wick and heating coil. It has been found that managing air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by the insert 601, and the additional insert 605, 607, 609, 611 if present, channel the air flow as to direct the air flow onto the capillary wick and heating coil in a substantially radial direction. This provides the capillary wick and heating coil with cool, non-saturated air, which decreases the particle size of the aerosol inhaled by a user. The guides provided by the housing inside walls 603 reduce the volume of the cavity in the smoking system and therefore improve aerosol flow towards the air outlet. This improves the smoking experience.

A number of variations are possible in the smoking systems of Figures 7a to 7e. Firstly, although the cross section of the device is shown as circular in Figures 7a to 7e, this need not be the case. Secondly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (inserts 601, 605, 607, 609 and 611, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing (shaped housing inside walls 603, as shown) or as a combination of both. The insert 601 is shown without channels, although longitudinal channels towards the outside of the insert may be provided. In addition, if channels are provided, the insert may extend across the entire cross section of the housing. Any configuration of channels may be provided. The channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. The channels in inserts 601, 605, 609, 611 and the holes in insert 607 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. Any number of holes or channels may be formed in inserts 605, 607, 609, 611. Preferably, the insert 601 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example. The inserts 605, 607, 609, 611 may also be provided with such a locating pin or protrusion. The housing inside walls 603 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber within the smoking system.

Figures 8a to 8c show a seventh embodiment of the smoking system according to the invention. Figure 8a shows a cross sectional view of the mouthpiece end of the sixth embodiment of the smoking system 700. In Figure 8a, the smoking system 700 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided by removable insert 701 and by the housing walls 703. The air flow is shown by the dotted arrows.

The removable insert 701 is similar to removable insert 601 shown in Figures 7a to 7e and extends only across the centre of the smoking system 700, thereby directing the air flow between the air inlet and the capillary wick and heating coil to the outer circumference of the device. In Figure 8a, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 701, although this need not be the case.

In addition, the housing inside walls 703 provide guides for channelling the aerosol flow onto the capillary wick and heating coil, and between the capillary wick and heating coil and the air outlet. The housing inside walls 703 also define the aerosol forming chamber 702. In this embodiment, the housing walls 703 are shaped so that the incoming air flow onto the capillary wick and heating coil is directed in an upstream channel 705 tangential to the circular cross section of the device and the circular cross section of the aerosol forming chamber 702.

Figure 8b is a cross section along line D-D of Figure 8a. In Figure 8a the housing inside walls 703 are shaped so that the channel 705 provides an air flow towards the capillary wick and heating coil that is in the tangential direction. This produces a spiralling air flow around the capillary wick and heating coil towards the air outlet.

Figure 8c is a cross section also along line D-D showing an alternative arrangement, in which two channels 705, 705' towards the capillary wick and heating coil are provided. Both channels direct the air flow in a tangential direction and together they produce a spiralling air flow around the capillary wick and heating coil towards the air outlet. Additional tangential upstream channels could also be provided.

The embodiment shown in Figures 8a, 8b and 8c provides a substantially tangentially directed air flow onto the capillary wick and heating coil and a substantially spiralling air flow around the capillary wick and heating coil and from the capillary wick and heating coil to the air outlet. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The shaped inside walls 703 of the housing, together with the insert 701 direct the air flow so as to supply cool and non-saturated air to the capillary wick and heating coil. Once air flow targets the capillary wick and heating coil, it is immediately evacuated towards the air outlet. This decreases the particle size of the aerosol inhaled by a user. The spiralling air flow around the capillary wick and heating coil increases turbulence and reduces aerosol particle size. The size of the tangential channel or channels and its position relative to the longitudinal axis of the device influence the air flow around the capillary wick and heating coil and therefore the aerosol characteristics. In addition, the centrifugal forces in the spiralling air flow may allow larger aerosol particles to impact and be trapped on the outer walls of the aerosol forming chamber 702. This is shown schematically in Figure 8a. The arrangement of Figure 8c further improves aerosol formation by providing a better flow distribution within the aerosol forming chamber.

A number of variations are possible in the smoking system of Figures 8a, 8b and 8c. The cross section of the device is preferably circular, so that the channel 705 can define a tangential air flow. However, other cross sectional shapes are also possible, as long as some sort of upstream tangential channel can be defined. More than one air inlet (in the housing) may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (removable insert 701 combined with shaped housing walls 703, as shown). Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing (shaped housing inside walls 703, as shown) or as a combination of both. The insert 701 is shown without channels, although longitudinal channels towards the outside of the insert 701 may be provided. In addition, if channels are provided, the insert may extend across the entire cross section of the housing. Any configuration of channels may be provided. The channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. Any channels in insert 701 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. The insert 701 may comprise a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example. The housing inside walls 703 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber within the smoking system. This affects the spiralling aerosol flow around the capillary wick and heating coil and therefore the aerosol characteristics. The tangential channels 705, 705' may be positioned at any height along the capillary wick and may have any suitable cross section.

Figures 9a to 9c show an eighth embodiment of the smoking system according to the invention. Figure 9a shows a cross sectional view of the mouthpiece end of the seventh embodiment of the smoking system 800. In Figure 9a, the smoking system 800 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided by removable insert 801, in the shaped housing walls 803 and by impactor 807. The air flow is shown by the dotted arrows.

The removable insert 801 is similar to removable insert 601 shown in Figures 7a to 7e and removable insert 701 shown in Figure 8a and extends only across the centre of the smoking system 800, thereby directing the air flow between the air inlet and the capillary wick and heating coil to the outer circumference of the device. In Figure 9a, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 801, although this need not be the case.

In addition, the housing inside walls 803 provide guides for channelling the air flow onto the capillary wick and heating coil. In this embodiment, the housing walls 803 are shaped so that the incoming air flow onto the capillary wick and heating coil is directed through an upstream channel 805 tangential to the circular cross section of the device and the circular cross section of the aerosol forming chamber 802.

In addition, an impactor 807 is provided at the downstream end of the capillary wick and heating coil. The impactor provides guides for channelling the air flow away from the capillary wick and heating coil and towards the air outlet. The impactor 807, in conjunction with the housing inside walls, also defines the aerosol forming chamber 802. The air flow is directed away from the capillary wick and heating coil in the radial direction in downstream channels 809, that is to say, substantially perpendicular to the longitudinal axis of the housing. The impactor 807 allows larger aerosol particles to be trapped on its upstream side. This is shown schematically in Figure 9a. The housing inside walls 803 may be tapered to direct the air flow towards the air outlet, although this is not shown in Figure 9a.

Figure 9b is a cross section along line E-E of Figure 9a showing the upstream channel 805. The housing walls 803 are shaped so that the channel 805 provides an air flow towards the capillary wick and heating coil that is in the tangential direction. This produces a spiralling air flow around the capillary wick and heating coil.

Figure 9c is a cross section along line F-F of Figure 9a showing the downstream channels 809. The impactor 807 and housing walls 803 cooperate so that the channels 809 provide an air flow away from the capillary wick and heating coil that is in substantially the radial direction. That is to say, downstream of the spiralling air flow around the capillary wick and heating coil, the aerosol flow is directed in the radial direction and then towards the air outlet.

The embodiment shown in Figures 9a, 9b and 9c provides a substantially tangentially directed air flow onto the capillary wick and heating coil, a substantially spiralling air flow around the capillary wick and heating coil and a substantially radially directed air flow away from the capillary wick and heating coil to the air outlet. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The shaped inside walls 803 of the housing, together with the insert 801 direct the air flow so as to supply cool and non-saturated air to the capillary wick and heating coil. This decreases the particle size of the aerosol inhaled by a user. The spiralling air flow around the capillary wick and heating coil increases turbulence and reduces aerosol particle size. Larger aerosol particles may also become trapped on the inside walls of the aerosol forming chamber 802 due to centrifugal forces. This is shown schematically in Figure 9a. The radially directed outgoing air flow means that once air flow targets the capillary wick and heating coil, it is immediately evacuated towards the air outlet. Additional upstream tangential channels may be provided (as in Figure 8c for example) which may provide a better flow distribution within the aerosol forming chamber. The size of the tangential channel or channels and its position relative to the longitudinal axis of the device influence the air flow around the capillary wick and heating coil and therefore the aerosol characteristics. In addition, the impactor may allow larger aerosol particles to impact on its upstream wall. This is shown schematically in Figure 9a.

A number of variations are possible in the smoking system of Figures 9a, 9b and 9c. The cross section of the device is preferably circular, so that the channel 805 can define a tangential air flow. However, other cross sectional shapes are also possible, as long as an upstream tangential channel can be defined. More than one air inlet (in the housing) may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (removable insert 801 combined with shaped housing walls 803, as shown). Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (shaped housing inside walls 803 combined with impactor 807, as shown). The insert 801 is shown without channels, although longitudinal channels towards the outside of the insert 801 may be provided. In addition, if channels are provided, the insert may extend across the entire cross section of the housing. Any configuration of channels may be provided. The channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. Any channels in insert 801 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. The insert 801 may comprise a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This is important for the electrical connections to the heating coil, for example. The housing inside walls 803 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber within the smoking system. This affects the spiralling aerosol flow around the capillary wick and heating coil and therefore the aerosol characteristics. The tangential channel 805 may be positioned at any height along the capillary wick and may have any suitable cross section. Any number of radial channels 809 may be provided. The impactor 807 may be formed with any appropriate shape and is preferably designed in conjunction with the shaped housing inside walls 803, in order to channel the air flow as desired.

Figures 10a to 10d show a ninth embodiment of the smoking system according to the invention. Figure 10a shows a cross sectional view of the mouthpiece end of the eighth embodiment of the smoking system 900. In Figure 10a, the smoking system 900 includes guides for channelling the air flow within the smoking system. In this embodiment, the guides are provided in removable insert 901 and in the shaped housing walls 903. The air flow is shown by the dotted arrows.

The removable insert 901 is similar to removable inserts 601, 701 and 801 and extends only across the centre of the smoking system 900, thereby directing the air flow between the air inlet and the capillary wick and heating coil to the outer circumference of the housing. In Figure 10a, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 901, although this need not be the case.

In addition, the housing inside walls 903 provide guides for channelling the aerosol flow onto the capillary wick and heating coil and off the capillary wick and heating coil. In this embodiment, the housing walls 903 are shaped so that the incoming air flow onto the capillary wick and heating coil is directed through an upstream channel 905 tangential to the circular cross section of the housing and the circular cross section of the aerosol forming chamber 902. In addition, the housing walls 903 are shaped so that the outgoing air flow off the capillary wick and heating coil is directed through an downstream channel 907 also tangential to the circular cross section of the housing and the circular cross section of the aerosol forming chamber 902. In addition, the housing walls 903 are shaped to provide an impactor surface 909 downstream of the capillary wick and heating coil. The surface 909 may allow larger aerosol particles to be trapped. This is shown schematically in Figure 10a. The housing inside walls also define the aerosol forming chamber 902. The housing inside walls 903 may be tapered to direct the air flow towards the air outlet, although this is not shown in Figure 10a.

Figure 10b is a cross section along line G-G of Figure 10a showing the upstream channel 905. The housing walls 903 are shaped so that the channel 905 provides an air flow towards the capillary wick and heating coil that is in the tangential direction. This produces a spiralling air flow around the capillary wick and heating coil.

Figure 10c is a cross section along line H-H of Figure 10a showing the downstream channel 907. The housing walls 903 are shaped so that the channel 907 provides an air flow away from the capillary wick and heating coil that is in the tangential direction. That is to say, after the air has spiralled around the capillary wick and heating coil, it is directed in the tangential direction and then towards the air outlet.

Figure 10d shows an alternative cross section along line H-H of Figure 10a, also showing downstream channel 907'. In Figure 10c, the channel 907 is on the same side of the device as the channel 905. In Figure 10d, the channel 907' is on the opposite side of the device as the channel 905.

The embodiment shown in Figures 10a, 10b, 10c and 10d provides a substantially tangentially directed air flow onto the capillary wick and heating coil, a substantially spiralling air flow around the capillary wick and heating coil and a substantially tangentially directed air flow off the capillary wick and heating coil and then to the air outlet. It has been found that managing the air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The shaped inside walls 903 of the housing, together with the insert 901 direct the air flow so as to supply cool and non-saturated air to the capillary wick and heating coil. This decreases the particle size of the aerosol inhaled by a user. The spiralling air flow around the capillary wick and heating coil increases turbulence and reduces aerosol particle size. Larger aerosol particles may also become trapped on the inside walls of the aerosol forming chamber 902 due to centrifugal forces. This is shown schematically in Figure 10a. The tangentially directed outgoing air flow means that once air flow has circled the capillary wick and heating coil, it is immediately evacuated towards the air outlet. Additional upstream or downstream tangential channels may be provided which may provide a better flow distribution within the aerosol forming chamber. The size of the tangential channels and their position relative to the longitudinal axis of the device influence the air flow around the capillary wick and heating coil and therefore the aerosol characteristics.

A number of variations are possible in the smoking system of Figures 10a, 10b, 10c and 10d. The cross section of the device is preferably circular, so that the channels 905 and 907 can define a tangential air flow. However, other cross sectional shapes are also possible as long as tangential channels can be defined. More than one air inlet (in the housing) may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (removable insert 901 combined with shaped housing walls 903, as shown). Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing (shaped housing walls 903, as shown) or as a combination of both. The insert 901 is shown without channels, although longitudinal channels towards the outside of the insert 901 may be provided. In addition, if channels are provided, the insert may extend across the entire cross section of the housing. Any configuration of channels may be provided. The channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. Any channels in insert 901 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. The insert 901 may comprise a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This is important for the electrical connections to the heating coil, for example. The housing inside walls 903 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber within the smoking system. This affects the spiralling aerosol flow around the capillary wick and heating coil and therefore the aerosol characteristics. The tangential channels 905, 907 may be positioned at any height along the capillary wick and may have any suitable cross section. Any number of tangential upstream and downstream channels may be provided.

Figures 11a to 11d show a tenth embodiment of the smoking system according to the invention. Figure 11a shows a cross sectional view of the smoking system including removable insert 1001. Figure 11b is a cross section along line B-B of Figure 11a, showing the mouthpiece end only. Figure 11c is a cross section along line C-C of Figure 11a, showing the mouthpiece end only. In Figures 11a, 11b and 11c, the smoking system 1000 includes guides for channelling the air flow within the smoking system. The air flow is shown by the dotted arrows.

The removable insert 1001 is shown in cross section in Figure 11a. The insert includes upstream channels 1003 for channelling the air flow from the air inlet onto the capillary wick and heating coil and downstream channels 1005 for channelling the air flow away from the capillary wick and heating coil towards the air outlet. The channels 1003 and 1005 are substantially perpendicular to one another and also substantially perpendicular to the longitudinal axis of the housing.

Figure 11b shows a cross section along B-B of Figure 11a and Figure 11c shows a cross section along C-C of Figure 11a. As seen in Figures 11b and 11c, in this embodiment, the guides are provided by removable insert 1001 and removable insert 1007. The removable insert 1007 is similar to removable inserts 601, 701, 801 and 901 and extends only across the centre of the smoking system 1000, thereby directing the air flow between the air inlet and the capillary wick and heating coil to the outer circumference of the housing. In Figures 11b and 11c, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 1007, although this need not be the case. The removable insert 1001 is positioned around the capillary wick and heating coil. The removable insert 1001 extends across the entire cross section of the device.

Because Figure 11b shows a cross section along B-B of Figure 11a, Figure 11b shows the air flow upstream of the capillary wick and heating coil. As shown in Figures 11a and 11b, the channels 1003 direct the air flow onto the capillary wick and heating coil in a substantially radial direction, that is to say, substantially perpendicular to the longitudinal axis of the housing.

Because Figure 11c shows a cross section along C-C of Figure 11a, Figure 11c shows the air flow downstream of the capillary wick and heating coil. As shown in Figures 11a and 11c, the channels 1005 direct the air flow away from the capillary wick and heating coil in a substantially radial direction. In addition, the channels 1005 define the aerosol forming chamber 1002.

The housing walls may additionally be tapered towards the air outlet, although this is not shown in Figures 11b and 11c.

Figure 11d shows an alternative arrangement for the removable insert 1001'. In this embodiment, the insert includes four upstream channels 1003' for channelling the air flow from the air inlet onto the capillary wick and heating coil. As in Figure 11a, the insert also includes two downstream channels 1005' for channelling the air flow away from the capillary wick and heating coil towards the air outlet. The channels 1003' and 1005' are substantially perpendicular to the longitudinal axis of the housing. The channels are directed in the radial direction. Although two upstream channels 1003 are shown in Figure 11a and four upstream channels 1003' are shown in Figure 11d, any suitable number of upstream channels may be provided, all in the radial direction and substantially perpendicular to the longitudinal axis of the housing. Similarly, although two downstream channels 1005, 1005' are shown in Figures 11a and 11d, any suitable number of downstream channels may be provided, all in the radial direction and substantially perpendicular to the longitudinal axis of the housing.

The embodiments shown in Figures 11a to 11d provide a substantially radially directed air flow onto the capillary wick and heating coil and a substantially radially directed air flow off the capillary wick and heating coil. It has been found that managing air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by the inserts 1007 and 1001 channel the air flow as to direct the air flow onto the capillary wick and heating coil in a substantially radial direction. This provides the capillary wick and heating coil with cool, non-saturated air, which decreases the particle size of the aerosol inhaled by a user. The guides provided by the insert 1001 channel the air flow as to direct the air flow off the capillary wick and heating coil in a substantially radial direction and also reduce the volume of the aerosol forming chamber 1002 in the smoking system. This improves aerosol flow towards the air outlet. This improves the smoking experience.

A number of variations are possible in the smoking system of Figures 11a to 11d. Firstly, although the cross section of the device is shown as circular in Figures 11a to 11d, this need not be the case. Secondly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (inserts 1001 and 1007, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions (insert 1001, as shown) or alternatively as an integral part of the housing or as a combination of both. The insert 1007 is shown without channels, although longitudinal channels towards the outside of the insert may be provided. In addition, if channels are provided, the insert may extend across the entire cross section of the housing. Any configuration of channels may be provided. The channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. The channels in insert 1007 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. Preferably, the insert 1007 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This is important for the electrical connections to the heating coil, for example.

Any suitable configuration of channels may be provided in insert 1001. The channels may be evenly or non-evenly distributed circumferentially around the insert. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels in insert 1001 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. Preferably, the insert 1001 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This is important for the electrical connections to the heating coil, for example. The channels 1005 may be shaped appropriately for the desired volume and shape of the aerosol forming chamber within the smoking system.

Figures 12a to 12n show an eleventh embodiment of the smoking system according to the invention. In each of Figures 12a to 12n, the smoking system includes guides for channelling the air flow within the smoking system. The air flow is shown by the dotted arrows.

Figure 12a shows a first arrangement of the smoking system 1100, and Figure 12b is a cross section along line J-J of Figure 12a. In Figures 12a and 12b, the guides are provided by removable insert 1101, second removable insert 1103 and by the shaped housing inside walls 1105. The removable insert 1101 extends only across the centre of the smoking system 1100, thereby directing the air flow between the air inlet and the capillary wick and heating coil to the outer circumference of the housing. In Figure 12a, the liquid cartridge, the capillary wick and the heating coil all form part of the removable insert 1101, although this need not be the case.

The second removable insert 1103 is shaped so that the air flow is directed across the capillary wick and heating coil in a substantially perpendicular direction. That is to say, the air flow is substantially perpendicular to the longitudinal axis of the housing and to the capillary wick. The second removable insert 1103 provides an upstream channel 1107 on one side of the insert and a downstream channel 1109 on the other side of the insert. When the insert is positioned around the capillary wick and heating coil, the air therefore flows directly across the capillary wick and heating coil. The insert 1103 also defines the aerosol forming chamber 1102.

In addition, the housing inside walls 1005 provide guides for channelling the air and aerosol flow between the capillary wick and heating coil and the air outlet. In this embodiment, the housing inside walls 1105 are tapered towards the air outlet so as to direct the air and aerosol flow towards the air outlet.

Figure 12c shows a second arrangement of the smoking system 1100' and Figure 12d is a cross section along line K-K of Figure 12c. The arrangement shown in Figures 12c and 12d is identical to that shown in Figures 12a and 12b except that second removable insert 1103 includes a perturbator 1111 surrounding the capillary wick and heating coil. In this embodiment, the perturbator 1111 comprises a cylindrical tube surrounding the capillary wick and heating coil, with holes to direct the air flow onto and away from the capillary wick and heating coil. This provides additional turbulence in the aerosol forming chamber 1102.

Figure 12e shows another embodiment of removable insert 1103'. The embodiment shown in Figure 12e is identical to that shown in Figure 11b except that the aerosol forming chamber is formed with restrictions 1117 towards the downstream side. The restrictions 1117 provide turbulence and, in particular, allow the air flow to strike the downstream side of the capillary wick and heating coil.

Figure 12f shows another embodiment of removable insert 1103". The embodiment shown in Figure 12f provides two upstream channels 1107a and 1107b on opposite sides of the insert and two downstream channels 1109a and 1109b on opposite sides of the insert. Air flow is directed from upstream channel 1107a, directly across the capillary wick and heating coil, towards downstream channel 1109b. At the same time, air flow is directed in the opposite direction from upstream channel 1107b, directly across the capillary wick and heating coil, towards downstream channel 1109a. This provides additional turbulence. In Figure 12f, the aerosol forming chamber is formed with divisions 1119. This prevents or reduces flow from upstream channel 1107a to downstream channel 1109a and from upstream channel 1107b to downstream channel 1109b. In Figure 12f, the aerosol forming chamber is formed with restrictions 1117' towards each downstream side, although the restrictions 1117' may be omitted. The restrictions 1117' provide turbulence and, in particular, allow the air flow to strike the downstream side of the capillary wick and heating coil.

Figure 12g shows another arrangement of the smoking system. In Figure 12g, only the liquid cartridge, the capillary wick and the heating coil are shown for clarity. Figure 12h is a cross section, similar to the cross sections in Figures 12b, 12d, 12e and 12f, but showing the Figure 12g arrangement. In Figures 12g and 12h, two pins 1119, 1121 are provided in the air flow across the capillary wick and heating coil. The pins direct the air flow and provide further turbulence in the aerosol forming chamber. In the embodiment shown in Figures 12g and 12h, the pins are the connection pins for the heating coil, pin 1119 being the positive connection, pin 1121 being the negative connection. However, this need not be the case.

Figure 12i shows an alternative version for the arrangement shown in Figure 12g. In Figure 12i, the pins 1119', 1121' are formed as flags. Pin 1119' has a pin portion 1119a at its base and a wider blade portion 1119b at its upper part. Similarly, pin 1121' has a pin portion 1121a at its base and a wider blade portion 1121b at its upper part. This provides better direction of the air flow across the capillary wick and heating coil. Figure 12j shows another alternative version for the arrangement shown in Figure 12g. In Figure 12j, the pins are formed as wide heating blades 1119", 1121". Again, this provides better direction of the air flow across the capillary wick and heating coil.

Figures 12k and 12l show two alternative arrangements for the pins shown in Figures 12i and12j. Figure 12k is a cross section, similar to the cross sections in Figures 12b, 12d, 12e, 12f and 12h. As shown in Figure 12k, the blade portions of the pins may be straight and directed in the downstream direction, that is to say, towards the downstream channel 1109. Figure 12l is a cross section, similar to the cross sections in Figures 12b, 12d, 12e, 12f, 12h and 12k. As shown in Figure 12l, the blade portions of the pins may be curved and directed in the downstream direction, that is to say, towards the downstream channel 1109.

The embodiments shown in Figures 12a to 12l provide a substantially radially directed air flow onto the capillary wick and heating coil and a substantially radially directed air flow off the capillary wick and heating coil. In particular, the air flow is directed across the capillary wick and heating coil. It has been found that managing air flow in this way improves the aerosol formation occurring within the smoking system. The air flow management may also reduce condensation and hence leakage. The guides provided by the inserts 1101 and 1103 channel the air flow as to direct the air flow onto the capillary wick and heating coil in a substantially radial direction. This provides the capillary wick and heating coil with cool, non-saturated air, which decreases the particle size of the aerosol inhaled by a user. The guides provided by the insert 1103 channel the air flow as to direct the air flow off the capillary wick and heating coil in a substantially radial direction and also reduce the volume of the aerosol forming chamber in the smoking system. This improves aerosol flow towards the air outlet. In addition, in the air flow, additional components may be provided to increase turbulence. This improves the smoking experience.

A number of variations are possible in the smoking system of Figures 12a to 12l. Firstly, although the cross section of the device is shown as circular in Figures 12a to 12l, this need not be the case. Secondly, more than one air inlet may be provided. The guides upstream of the capillary wick and heating coil may be formed as one or more removable portions (inserts 1101 and 1103, as shown) or alternatively as an integral part of the housing or as a combination of both. Similarly, the guides downstream of the capillary wick and heating coil may be formed as one or more removable portions or alternatively as an integral part of the housing or as a combination of both (insert 1103 and shaped housing walls 1105, as shown). The insert 1101 is shown without channels, although longitudinal channels towards the outside of the insert may be provided. In addition, if channels are provided, the insert may extend across the entire cross section of the housing. Any configuration of channels may be provided. The channels may be twisted around the axis of the housing, so as to encourage a swirled airflow. The channels in insert 1101 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. Preferably, the insert 1101 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. This may be important for the electrical connections to the heating coil, for example.

Any suitable configuration of channels may be provided in insert 1103 including any suitable number of upstream channels and any suitable number of downstream channels. The channels may have a constant cross sectional shape and area along their length, or the cross sectional shape can vary along the length. The channels may include some channels having different cross sectional shapes and areas from others. The channels in insert 1103 may be formed by machining. Alternatively, the insert may be formed with channels or holes already formed, by injection moulding. Preferably, the insert 1103 comprises a locating pin or protrusion (not shown) on its outer surface for cooperating with a recess (also not shown) on the inside of the housing walls, so as to ensure that the insert is correctly positioned within the smoking system. The insert 1103 may be shaped appropriately for the desired volume of the aerosol forming chamber within the smoking system.

The pins shown in Figures 12g to 12l may have suitable shape in order to direct the air flow across the capillary wick and heating element as desired. In addition, although the pins are shown as the connections to the heating coil, this need not be the case.

A large number of embodiments have been described and it should be understood that features described in relation to one embodiment may also apply to another embodiment, where appropriate.

Claims

An electrically heated smoking system (100) comprising:
a housing (101);

an electric power supply (107);

electric circuitry (109);

a liquid storage portion (113);

a capillary wick (117) for holding liquid (115), the capillary wick having a fibrous or spongy structure and arranged to be in contact with liquid in the liquid storage portion;

at least one heater (119) for heating the liquid in at least a portion of the capillary wick to form an aerosol, the heater comprising a coil of wire at least partially surrounding the capillary wick;

at least one air inlet (123), at least one air outlet (125) and a chamber (127) between the air inlet and air outlet, the air inlet, the air outlet and the chamber being arranged so as to define an air flow route from the air inlet to the air outlet via the capillary wick so as to convey the aerosol to the air outlet;

at least one guide (501, 503, 505) for channeling the air flow in the air flow route, the at least one guide provided by the internal shape of the housing, the at least one guide defining a constricted air flow cross section over the wick; and

an impactor (505) for trapping larger aerosol particles, the impactor provided by the internal shape of the housing, the impactor being downstream of the capillary wick,

wherein the housing comprises a shell (105) and a replaceable mouthpiece (103), the electric power supply and the electric circuitry being contained in the shell, the liquid storage portion, the capillary wick, the at least one heater and the air outlet being contained in the mouthpiece.
An electrically heated smoking system (100) according to claim 1, wherein the at least one guide (501, 503, 505) is upstream of the wick (117).
An electrically heated smoking system (100) according to any preceding claim, wherein the at least one guide (501, 503, 505) is downstream of the wick (117).
An electrically heated smoking system (100) according to any preceding claim, wherein the at least one guide (501, 503, 505) is arranged so that the air flow speed over the wick (117) is greater than the air flow speed upstream of the wick.
An electrically heated smoking system (100) according to any preceding claim, wherein the at least one guide (501, 503, 505) is arranged to control the particle size of the aerosol to have a diameter substantially less than 1.5 micro meters.
An electrically heated smoking system (100) according to any preceding claim, wherein the air inlet (123) is contained in the shell (105).
An electrically heated smoking system (100) according to any preceding claim, comprising at least two air inlets (123).
An electrically heated smoking system (100) according to any preceding claim, wherein the internal shape of the housing (101) at least partially defines the shape of the chamber (127).
An electrically heated smoking system (100) according to any preceding claim, wherein the chamber (127) surrounds or is downstream of the capillary wick (117).
An electrically heated smoking system (100) according to any preceding claim, wherein the capillary wick (117) is elongate and wherein the at least one guide (501, 503, 505) is configured to channel the air flow onto the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick.
An electrically heated smoking system (100) according to any preceding claim, wherein the capillary wick (117) is elongate and wherein the at least one guide (501, 503, 505) is configured to channel the air flow off the capillary wick in a direction substantially perpendicular to the longitudinal axis of the capillary wick.
An electrically heated smoking system (100) according to any preceding claim, comprising an acceleration nozzle (503) for directing the aerosol towards the impactor (505), the nozzle defining a decreasing cross sectional area of the air flow route.
An electrically heated smoking system (100) according to any preceding claim, wherein the shell (105) and mouthpiece (103) are arranged to releasably lock together when engaged.