WO2023001685A1

WO2023001685A1 - Vapour generating device

Info

Publication number: WO2023001685A1
Application number: PCT/EP2022/069741
Authority: WO
Inventors: Andrew Robert John ROGAN; Alec WRIGHT
Original assignee: Jt International Sa
Priority date: 2021-07-21
Filing date: 2022-07-14
Publication date: 2023-01-26
Also published as: EP4373337A1

Abstract

A vapour generating device comprises an air inlet, a vapour outlet, an airflow passage (32) extending between the air inlet and the vapour outlet, and a vaporizing unit (30) for vaporizing a vapour generating substance to generate a vapour for delivery to a user through the airflow passage via the vapour outlet. The vapour generating device comprises a rotary airflow regulator (34) and a rotational biasing member. The rotary airflow regulator is positioned in the airflow passage and configured for rotation in a first direction (A) by an airflow through the airflow passage from the air inlet to the vapour outlet resulting from a user inhalation. The rotational biasing member is configured to apply a torque to the rotary airflow regulator in a second direction (B) opposite to the first direction, and is configured to prevent rotation of the rotary airflow regulator in the first direction resulting from a user inhalation when the applied torque exceeds a threshold value corresponding to the user inhalation.

Description

VAPOUR GENERATING DEVICE

Technical Field

The present disclosure relates generally to a vapour generating device, and more particularly to a vapour generating device for transforming a vapour generating substance into a vapour or aerosol for inhalation by a user. The present disclosure is particularly applicable to a portable (hand-held) vapour generating device.

Technical Background The popularity and use of reduced-risk or modified-risk devices (also known as aerosol generating devices or vapour generating devices or personal vaporizers) has grown rapidly in recent years as an alternative to the use of traditional tobacco products.

Various devices and systems are available that include a vaporizing unit to transform a vapour generating substance into a vapour or aerosol for inhalation by a user. The vaporizing unit may, for example, be configured to heat or warm the vapour generating substance to generate a vapour which cools and condenses to form an aerosol for inhalation by a user of the vapour generating device. Thus, the vaporizing unit typically includes an electrically-operated heater, for example a resistive heater or an induction heater and associated susceptor.

The vapour generating substance can be in liquid form, in solid form, or in a semi-liquid form. So, it may be a liquid, gel, paste or wax or the like, or any combination of these. The vapour generating substance typically contains one or more active components, such as nicotine, and it may, therefore, be desirable to regulate the amount of the active component(s) that is/are inhaled by a user (as a vapour or aerosol) during a single user inhalation (or “puff’), in other words to regulate or control the dosage of the active component(s) that is/are inhaled by a user. The present disclosure aims to address this need. Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided a vapour generating device comprising: an air inlet; a vapour outlet; an airflow passage extending between the air inlet and the vapour outlet; a vaporizing unit for vaporizing a vapour generating substance to generate a vapour for delivery to a user through the airflow passage via the vapour outlet; a rotary airflow regulator positioned in the airflow passage and configured for rotation in a first direction by an airflow through the airflow passage from the air inlet to the vapour outlet resulting from a user inhalation; and a rotational biasing member configured to apply a torque to the rotary airflow regulator in a second direction opposite to the first direction, wherein the rotational biasing member is configured to prevent rotation of the rotary airflow regulator in the first direction resulting from a user inhalation when the applied torque exceeds a threshold value corresponding to the user inhalation.

The vapour generating device, and in particular the vaporizing unit, may be configured to heat the vapour generating substance, without burning the vapour generating substance, to volatise at least one component of the vapour generating substance and thereby generate a vapour or aerosol. In some examples, the vapour may cool and condense to form an aerosol. The vapour generating device is a hand-held, portable, device. In general terms, a vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapour’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user. The torque applied by the rotational biasing member to the rotary airflow regulator in the second direction applies a restraint to movement of the rotary airflow regulator in the first direction when the applied torque exceeds the threshold value (in other words, when the applied torque is greater than the torque applied by the airflow that results from a user inhalation or “puff’) and also provides a restoring force in the second direction upon the release of pressure or suction by a user at the end of an inhalation or “puff’.

Thus, the present disclosure allows the airflow through the vapour generating device (specifically through the airflow passage) to be regulated or controlled, and this in turn allows the amount (or dosage) of vapour or aerosol inhaled by a user during a single user inhalation (or “puff’) to be regulated or controlled. In particular, the rotary airflow regulator regulates or controls the flow of air through the airflow passage. When rotation of the rotary airflow regulator is prevented by the rotational biasing member (because the applied torque exceeds the threshold value), the airflow passage is occluded or obstructed by the rotary airflow regulator thereby substantially preventing airflow through the airflow passage. Thus, a simple mechanical mechanism is provided for regulating or controlling the airflow through the airflow passage of the vapour generating device and, thus, for controlling the amount (or dosage) of vapour or aerosol inhaled by a user.

Optional features will now be set out. These are applicable singly or in any combination with any aspect of the present disclosure.

The rotational biasing member may be configured for movement from a first state to a second state by a user inhalation. The applied torque may exceed the threshold value in the second state. The rotational biasing member may be coupled to the rotary airflow regulator and may be configured for movement from the first state to the second state by rotation of the rotary airflow regulator resulting from a user inhalation. The rotational biasing member thus prevents continued rotation of the rotary airflow regulator when it is in the second state, thus ensuring that airflow through the airflow passage is substantially prevented. By configuring the rotational biasing member so that it is moved from the first state to the second state by a user inhalation, and in particular by rotation of the rotatory airflow regulator, the biasing member is moved reliably to the second state when a user inhales and induces an airflow through the airflow passage that is sufficient to cause rotation of the rotary airflow regulator.

The rotational biasing member may be configured to apply said torque to the rotary airflow regulator in a direction opposite to a torque applied to the rotary airflow regulator resulting from a user inhalation. Thus, the rotational biasing member is very effective at preventing rotation of the rotary airflow regulator, for example when the rotational biasing member is in the second state.

The rotational biasing member may be configured to rotate the rotary airflow regulator in the second direction in the absence of a torque applied thereto in the first direction resulting from a user inhalation. When the rotational biasing member is in the second state, a user can no longer continue inhaling because continued rotation of the airflow regulator in the first direction is prevented by the rotational biasing member. When a user ceases inhalation by releasing pressure or suction at the vapour outlet, the rotational biasing member applies a torque or restoring force to the rotary airflow regulator, causing it to rotate in the second direction and allowing the rotational biasing member to return to the first state. When the rotational biasing member reaches the first state, rotation of the rotatory airflow regulator in the second direction may cease. With this arrangement, the rotational biasing member returns from the second state to the first state automatically, in the sense that the user does not have to perform an additional step to release or reset the rotational biasing member to allow it to return from the second state to the first state.

The rotary airflow regulator may be positioned upstream of the vaporizing unit in an airflow direction through the airflow passage from the air inlet towards the vapour outlet. By positioning the rotary airflow regulator upstream of the vaporizing unit, the formation of deposits of condensed vapour and/or aerosol on the rotary airflow regulator can be avoided. The rotary airflow regulator may be positioned downstream of the vaporizing unit in an airflow direction through the airflow passage from the air inlet towards the vapour outlet. It may be more convenient to position the rotary airflow regulator downstream of the vaporizing unit in some embodiments.

The rotary airflow regulator may comprise a paddle wheel which may have an axle. The axle may be mounted on the vapour generating device substantially perpendicular to an airflow direction through the airflow passage. The paddle wheel may be particularly effective at occluding or obstructing the airflow passage when the rotational biasing member is in the second state and rotation of the paddle wheel in the first direction is thereby prevented.

The rotational biasing member may be a spirally wound torsion spring, also commonly known as a mainspring. A spirally wound torsion spring (or mainspring) may be a particularly convenient form of rotational biasing member, in particular for use in combination with a rotary airflow regulator in the form of a paddle wheel.

The spirally wound torsion spring may be coupled to the axle to apply said torque to the rotary airflow regulator, e.g., paddle wheel. The spirally wound torsion spring may have an inner end which is attached to the axle. The axle thus acts as an arbor to which the inner end of the spirally wound torsion spring is attached. Thus, the applied torque is transmitted by the spirally wound torsion spring to the rotary airflow regulator, e.g., paddle wheel, via the axle, and this arrangement allows for suitable positioning of the rotary airflow regulator, e.g., paddle wheel, and the spirally wound torsion spring in the vapour generating device.

The vapour generating device may include a pretension mechanism which may be configured to apply a pretension force to the rotational biasing member when in the first state, such that the pretensioned rotational biasing member is configured to apply a torque to the rotary airflow regulator in the second direction which is less than the threshold value. The pretension mechanism may be user adjustable to allow adjustment of the pretension force. The application of a pretension force to the rotational biasing member reduces the amount of airflow through the airflow passage that is needed before the rotational biasing member reaches the second state and continued rotation of the rotary airflow regulator in the first direction is prevented by the rotational biasing member. In particular, as the pretension force increases, there is a corresponding reduction in the amount of airflow through the airflow passage that is needed before the rotational biasing member reaches the second state and continued rotation of the rotary airflow regulator in the first direction is prevented by the rotational biasing member. In embodiments in which the pretension force is user adjustable, a user can modify the amount of airflow that is permitted through the airflow channel before further rotation of the rotational airflow regulator in the first direction is prevented by the rotational biasing member and the airflow passage is occluded or obstructed. Thus, the user can modify the amount (or dosage) of vapour or inhaled during a single user inhalation (or “puff’) using a simple to operate mechanism.

The pretension mechanism may comprise a friction guide in which the rotational biasing member may be mounted and may comprise a user adjustable dial for applying a rotational pretension force to the rotational biasing member. The friction guide helps to maintain the rotational biasing member in the pretensioned state and helps to prevent the rotational biasing member returning to the first (relaxed) state. The user adjustable dial provides a simple and convenient means for a user to adjust the pretension force.

The vapour generating substance may contain one or more active components, such as nicotine.

The vapour generating substance may comprise a vapour generating liquid. In this case, the vapour generating device may be designated as an “E-vapour” device. The vapour generating liquid may comprise polyhydric alcohols and mixtures thereof such as glycerine or propylene glycol. The vapour generating liquid may contain one or more additives, such as a flavouring. The flavouring may include Ethylvanillin (vanilla), menthol, cherry, Isoamyl acetate (banana oil) or similar, for instance. The vapour generating substance may comprise a vapour generating substrate which may comprise any type of solid or semi-solid material. Example types of vapour generating solids include powder, granules, pellets, shreds, strands, particles, gel, strips, loose leaves, cut filler, porous material, foam material or sheets. The vapour generating substrate may comprise plant derived material and in particular, may comprise tobacco. It may advantageously comprise reconstituted tobacco, for example including tobacco and any one or more of cellulose fibres, tobacco stalk fibres and inorganic fillers such as CaC03.

Consequently, the vapour generating device may be referred to as a “heated tobacco device”, a “heat-not-bum tobacco device”, a “device for vaporising tobacco products”, a “T-vapour” device and the like, with this being interpreted as a device suitable for achieving these effects.

The vapour generating substrate may form part of a vapour generating article and may be circumscribed by a paper wrapper. The vapour generating article may be formed substantially in the shape of a stick, and may broadly resemble a cigarette, having a tubular region with vapour generating substrate arranged in a suitable manner. The vapour generating article may include a filter segment, for example comprising cellulose acetate fibres, at a proximal end of the vapour generating article. The filter segment may constitute a mouthpiece filter and may be in coaxial alignment with the vapour generating substrate. One or more vapour collection regions, cooling regions, and other structures may also be included in some designs. For example, the vapour generating article may include at least one tubular segment upstream of the filter segment. The tubular segment may act as a vapour cooling region. The vapour cooling region may advantageously allow the heated vapour generated by heating the vapour generating substrate to cool and condense to form an aerosol with suitable characteristics for inhalation by a user, for example through the filter segment.

The vapour generating substrate may comprise an aerosol-former. Examples of aerosol- formers include polyhydric alcohols and mixtures thereof such as glycerine or propylene glycol. Typically, the vapour generating substrate may comprise an aerosol- former content of between approximately 5% and approximately 50% on a dry weight basis. In some embodiments, the vapour generating substrate may comprise an aerosol- former content of between approximately 10% and approximately 20% on a dry weight basis, and possibly approximately 15% on a dry weight basis.

Upon heating, the aerosol generating substrate may release volatile compounds. The volatile compounds may include nicotine or flavour compounds such as tobacco flavouring.

The vaporizing unit may comprise a heater for heating the vapour generating substance. The heater may comprise a resistive heater or may comprise an electromagnetic field generator, e.g., including an induction coil, for heating an inductively heatable susceptor. The heater may comprise both the electromagnetic field generator and the inductively heatable susceptor. The electromagnetic field generator may be arranged to generate an alternating electromagnetic field for inductively heating the inductively heatable susceptor. This arrangement provides a particularly convenient way to heat the vapour generating substance using induction heating.

Brief Description of the Drawings

Figures la and lb are schematic side and cross-sectional views respectively of an example of a vapour generating device;

Figure 2 is a diagrammatic view of a rotary airflow regulator in the form of a paddle wheel; and

Figure 3 is a diagrammatic view of a rotational basing member in the form of a spirally wound torsion spring mounted in a friction guide and showing a user adjustable dial for applying a pretension force to the spirally wound torsion spring.

Detailed Description of Embodiments

Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings. As described hereinafter, example implementations of the present disclosure relate to a vapour generating device 10, in particular a portable hand-held smoking device such as an electronic cigarette. Vapour generating devices according to the present disclosure use electrical energy to heat and volatise a vapour generating substance without combusting the vapour generating substance and/or without significant chemical alteration of the vapour generating substance, to form an inhalable aerosol or vapour; and components of such device have the form of articles that most preferably are sufficiently compact to be considered hand-held devices. The use of the vapour generating device 10 does not result in the production of smoke in the sense that the vapour does not result from by-products of combustion or pyrolysis of tobacco, but rather, the use of the vapour generating device 10 results in the production of a vapour due to volatilization or vaporization of certain components incorporated in the vapour generating substance. The vapour generating substance may be a liquid or a solid, and the present disclosure is not limited in any way by the form of the vapour generating substance.

In some example implementations, the vapour generating device 10 may be characterized as an electronic cigarette in which the vapour generating substance may comprise a vapour generating liquid (e.g., propylene glycol or glycerine) or a vapour generating substrate (e.g., tobacco). Whatever the form of the vapour generating substance, vapour generating devices 10 within the meaning of the present disclosure may transport the volatilized components of the vapour generating substance in an airflow through the vapour generating device 10 to a user of the device 10, the user of the device 10 being able to activate or deactivate the generation of vapour and to control the duration, velocity and volume of the airflow by means of a puffing or inhaling action.

Referring to Figures 1 a and 1 b, there is shown an example of a vapour generating device 10 according to an embodiment of the present disclosure. The vapour generating device 10 comprises a mouthpiece portion 12 and a power supply portion 14. The power supply portion 14 can also be referred to as a main body 14 of the vapour generating device 10, and is advantageously configured as a re-usable unit. The power supply portion 14 comprises a power source 18 (e.g., a battery) and a controller 20 (e.g., a printed circuit board (PCB), an integrated circuit, a memory component, a microprocessor, individually or as part of a micro-controller, and the like) to control the operation of the vapour generating device 10.

The vapour generating device 10 includes an air inlet 23 and a vapour outlet 24 for delivering vapour or aerosol to the user. In the illustrated example, the mouthpiece portion 12 comprises a mouthpiece 22 and the vapour outlet 24 is formed in the mouthpiece 22. The mouthpiece portion 12 has an exterior housing 16a (or shell) which is configured to connect to a separable exterior housing 16b (or shell) of the power supply portion 14. In an embodiment, the mouthpiece portion 12 and the power supply portion 14 are connectable to each other by a releasable connection 26. The releasable connection 26 can be, for example, a threaded connection, a bayonet connection or a magnetic connection.

The vapour generating device 10 illustrated in Figures la and lb has an elongate and substantially cylindrical shape which resembles a cigarette or cigar. Other shapes are, however, entirely within the scope of the present disclosure. It should also be noted that in some examples, all of the components of the vapour generating device 10 can be contained within a single housing, rather than two separable exterior housings 16a, 16b as described with reference to Figures la and lb. In this case, the vapour generating device 10 is a one-piece device and does not include a releasable connection 26.

The vapour generating device 10 comprises a vaporizing unit 30 configured to heat and vaporize a vapour generating substance and thereby transform the vapour generating substance into a vapour which may cool and condense to form an aerosol for inhalation by a user through the vapour outlet 24 in the mouthpiece 22. The vaporizer unit 30 can be a consumable component (e.g., a cartomizer) positioned in the mouthpiece portion 12 as shown in Figure lb. The vaporizer unit 30 can alternatively be a reusable component positioned in the power supply portion 14. The vaporizer unit 30 includes a heater, for example a resistive heater or an induction heater with an associated susceptor, to heat the vapour generating substance. In examples in which the vapour generating substance is a vapour generating liquid, the vaporizer unit 30 may also include a liquid transport element, e.g., a capillary wick, to transport the vapour generating liquid to the heater.

The vapour generating device 10 includes an airflow passage 32 which extends between the air inlet 23 and the vapour outlet 24. When a user sucks or inhales on the mouthpiece 22, air flows through the airflow passage 32, from the air inlet 23 towards the vapour outlet 24. In general, the volume of air coming from the air inlet 23 is about 0ml - 150ml, more preferably 35 - 55ml. The vapour generated by the vaporizing unit 30 is entrained in the airflow and is delivered to the user via the vapour outlet 24. The vapour may cool and condense as it flows through the airflow passage 32 to form an inhalable aerosol.

In order to regulate the airflow through the airflow passage 32, the vapour generating device 10 comprises a rotary airflow regulator 34 positioned in the airflow passage 32. In the illustrated example, the rotary airflow regulator 34 is positioned upstream of the vaporizing unit 30 in an airflow direction through the airflow passage 32 from the air inlet 23 towards the vapour outlet 34. The airflow regulator 34 can, however, be positioned downstream of the vaporizing unit 30 in other (non-illustrated) examples.

Referring also to Figure 2, the rotary airflow regulator 34 can comprise a paddle wheel 36 positioned in the airflow passage and can have an axle 38 which is mounted on the vapour generating device 10 substantially perpendicular to the airflow direction through the airflow passage 32. The paddle wheel 36 rotates in a first direction, illustrated by the arrow A in Figure 2, when a user sucks or inhales on the mouthpiece 22 to draw air through the airflow passage 32 from the air inlet 23 to the air outlet 24. It is the airflow through the airflow passage 32 resulting from this user inhalation that causes the paddle wheel 36 to rotate in the first direction A.

The vapour generating device 10 also comprises a rotational biasing member 40 which is configured to apply a torque to the paddle wheel 36 in a second direction, illustrated by the arrow B in Figure 2, that is opposite to the first direction A. The rotational biasing member 40 is typically a spirally wound torsion spring 42 (or mainspring). The spirally wound torsion spring 42 has an inner end 42a coupled to the axle 38 to apply the torque to the paddle wheel 36 in the second direction B. The torsion spring 42 has an outer end 42b which is secured to the body or housing of the vapour generating device 10, or possibly to a user adjustable dial 48 as discussed below. The spirally wound torsion spring 42 is configured to prevent rotation of the rotary airflow regulator 34 in the first direction A resulting from a user inhalation when the torque applied by the spirally wound torsion spring 42 in the second direction B exceeds a threshold value that corresponds to a user inhalation, as will now be explained in further detail.

The spirally wound torsion spring 42 is configured for movement from a first state (relaxed state/resting state) to a second state (primed state/compressed state) when a user sucks or inhales on the mouthpiece 22 thanks to the flow of air through the airflow passage 32 resulting from the user inhalation. In the illustrated example, as the paddle wheel 36 rotates in the first direction A and causes a corresponding rotation of the axle 38, the inner end 42a of the spirally wound torsion spring 42 is also caused to rotate with the axle 38 and the spirally wound torsion spring 42 is wound up, in other words it is moved from the first (relaxed/resting) state to the second (primed/compressed) state. Thus, this movement of the spirally wound torsion spring 42 from the first (relaxed/resting) state to the second (primed/compressed) state occurs automatically, when a user sucks or inhales on the mouthpiece 22.

As the spirally wound torsion spring 42 moves from the first (relaxed/resting) state to the second (primed/compressed) state, it applies a torque (or restoring force) to the paddle wheel 36 in the second direction B. At first, the torque applied to the paddle wheel 36 in the first direction A, thanks to the flow of air through the airflow passage 32 that results from the user inhalation, is greater than the torque (or restoring force) applied in the second direction B by the spirally wound torsion spring 42. Eventually, however, the spirally wound torsion spring 42 reaches the second (primed/compressed) state at which it is wound sufficiently tight that the torque applied by the spirally wound torsion spring 42 to the paddle wheel 36 in the second direction B exceeds a threshold torque applied to the paddle wheel 36 in the first direction A, thanks to the flow of air through the airflow passage 32 resulting from the user inhalation. At this point, when the spirally wound torsion spring 42 reaches the second (primed/compressed) state, the paddle wheel 36 can no longer rotate in the first direction A. Thus, the airflow passage 32 is substantially occluded or blocked by the paddle wheel 36 and the flow of air through the airflow passage 32 is substantially prevented, thereby ensuring that the user can no longer continue inhaling. The amount (or dosage) of vapour or aerosol inhaled by the user during a single inhalation (or puff) is thereby controlled by the combination of the paddle wheel 36 and the spirally wound torsion spring 42.

When the user stops sucking or inhaling on the mouthpiece 22 by releasing pressure or suction at the vapour outlet 24, the torque (or restoring force) applied by the spirally wound torsion spring 42 to the paddle wheel 36 in the second direction B causes the paddle wheel 36 to rotate in the second direction B. In doing so, the spirally wound torsion spring 42 also returns from the second (primed/compressed) state to the first (relaxed/resting) state, at which point the rotation of the paddle wheel 36 in the second direction may cease. When the spirally wound torsion spring 42 has returned to the first (relaxed/resting) state, the user can again apply suction to the mouthpiece 22 to commence another inhalation phase in the manner described above.

In order to enable the user to control the amount (or volume) of air that must flow through the airflow passage 32 to move the spirally wound torsion spring 42 from the first (relaxed/resting) state to the second (primed/compressed) state, and to thereby control the amount (or dosage) of vapour or aerosol that can be inhaled during a single user inhalation or puff, the vapour generating device 10 can include a pretension mechanism 44 which applies a pretension force to the spirally wound torsion spring 42. This pretension force causes the spirally wound torsion spring 42 to apply a pretension torque to the paddle wheel 36 in the second direction B, but this pretension torque is lower than the threshold value of the torque applied to the paddle wheel 36 in the first direction A by a user inhalation, thus allowing the paddle wheel 36 to rotate in the first direction A as described above until the spirally wound torsion spring 42 reaches the second (primed/compressed) state at which the torque (or restoring force) applied by the spirally wound torsion spring 42 to the paddle wheel 36 in the second direction B cannot be overcome by the torque applied in the first direction A resulting from the user inhalation.

The pretension mechanism 44 can comprise a friction guide 46 mounted on, or formed in, the housing or body of the vapour generating device 10 in which the spirally wound torsion spring 42 is mounted. The friction guide 46 helps to maintain the pretension force in the spirally wound torsion spring 42, preventing it from returning to the first (relaxed/resting) state and rotating the paddle wheel 36 in the second direction B in the absence of a user inhalation. In order to permit user adjustment of the pretension force, the pretension mechanism 44 also comprises a user adjustable dial 48 which can be rotated by a user to apply a rotational pretension force of a desired magnitude to the spirally wound torsion spring 42.

Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments.

Any combination of the above-described features in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

Claims

1. A vapour generating device (10) comprising: an air inlet (23); a vapour outlet (24); an airflow passage (32) extending between the air inlet (23) and the vapour outlet (24); a vaporizing unit (30) for vaporizing a vapour generating substance to generate a vapour for delivery to a user through the airflow passage (32) via the vapour outlet (24); a rotary airflow regulator (34) positioned in the airflow passage (32) and configured for rotation in a first direction (A) by an airflow through the airflow passage (32) from the air inlet (23) to the vapour outlet (24) resulting from a user inhalation; and a rotational biasing member (40) configured to apply a torque to the rotary airflow regulator (34) in a second direction (B) opposite to the first direction (A), wherein the rotational biasing member (40) is configured to prevent rotation of the rotary airflow regulator (34) in the first direction (A) resulting from a user inhalation when the applied torque exceeds a threshold value corresponding to the user inhalation.

2. A vapour generating device according to claim 1 , wherein the rotational biasing member (40) is configured for movement from a first state to a second state by a user inhalation and the applied torque exceeds the threshold value in the second state.

3. A vapour generating device according to claim 2, wherein the rotational biasing member (40) is coupled to the rotary airflow regulator (34) and is configured for movement from the first state to the second state by rotation of the rotary airflow regulator (34) resulting from a user inhalation.

4. A vapour generating device according to any preceding claim, wherein the rotational biasing member (40) is configured to apply said torque to the rotary airflow regulator (34) in a direction (B) opposite to a torque applied to the rotary airflow regulator (34) resulting from a user inhalation.

5. A vapour generating device according to any preceding claim, wherein the rotational biasing member (40) is configured to rotate the rotary airflow regulator (34) in the second direction (B) in the absence of a torque applied thereto in the first direction (A) resulting from a user inhalation.

6. A vapour generating device according to any preceding claim, wherein the rotary airflow regulator (34) is positioned upstream of the vaporizing unit (30) in an airflow direction through the airflow passage (32) from the air inlet (23) towards the vapour outlet (24).

7. A vapour generating device according to any of claims 1 to 5, wherein the rotary airflow regulator (34) is positioned downstream of the vaporizing unit (30) in an airflow direction through the airflow passage (32) from the air inlet (23) towards the vapour outlet (24).

8. A vapour generating device according to any preceding claim, wherein the rotary airflow regulator (34) comprises a paddle wheel (36) having an axle (38).

9. A vapour generating device according to any preceding claim, wherein the rotational biasing member (40) is a spirally wound torsion spring (42).

10. A vapour generating device according to claims 8 and 9, wherein the spirally wound torsion spring (42) is coupled to the axle (38) to apply said torque to the paddle wheel (36).

11. A vapour generating device according to claim 2 or claim 3 or any of claims 4 to 10 when dependent on claim 2 or claim 3, wherein the vapour generating device (10) includes a pretension mechanism (44) configured to apply a pretension force to the rotational biasing member (40) when in the first state, such that the pretensioned rotational biasing member (40) is configured to apply a torque to the rotary airflow regulator (34) in the second direction (B) which is less than the threshold value.

12. A vapour generating device according to claim 11, wherein the pretension mechanism (44) is user adjustable to allow adjustment of the pretension force.

13. A vapour generating device according to claim 12, wherein the pretension mechanism (44) comprises a friction guide (46) in which the rotational biasing member (40) is mounted and a user adjustable dial (48) for applying a rotational pretension force to the rotational biasing member (40).