EP3794973A1 - Rauchersatzvorrichtung - Google Patents

Rauchersatzvorrichtung Download PDF

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Publication number
EP3794973A1
EP3794973A1 EP19198589.4A EP19198589A EP3794973A1 EP 3794973 A1 EP3794973 A1 EP 3794973A1 EP 19198589 A EP19198589 A EP 19198589A EP 3794973 A1 EP3794973 A1 EP 3794973A1
Authority
EP
European Patent Office
Prior art keywords
flow
air
bypass
aerosol
smoking substitute
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP19198589.4A
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English (en)
French (fr)
Inventor
designation of the inventor has not yet been filed The
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nerudia Ltd
Original Assignee
Nerudia Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nerudia Ltd filed Critical Nerudia Ltd
Priority to EP19198589.4A priority Critical patent/EP3794973A1/de
Priority to EP20789848.7A priority patent/EP3930497A1/de
Priority to PCT/EP2020/076285 priority patent/WO2021053221A1/en
Publication of EP3794973A1 publication Critical patent/EP3794973A1/de
Priority to US17/693,992 priority patent/US20220192258A1/en
Ceased legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
    • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
    • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
    • A24F40/48—Fluid transfer means, e.g. pumps
    • A24F40/485—Valves; Apertures
    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
    • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
    • A24F40/10—Devices using liquid inhalable precursors

Definitions

  • the present invention relates to a smoking substitute apparatus and, in particular, a smoking substitute apparatus that is able to deliver nicotine to a user in an effective manner.
  • the smoking of tobacco is generally considered to expose a smoker to potentially harmful substances. It is thought that a significant amount of the potentially harmful substances are generated through the burning and/or combustion of the tobacco and the constituents of the burnt tobacco in the tobacco smoke itself.
  • Such smoking substitute systems can form part of nicotine replacement therapies aimed at people who wish to stop smoking and overcome a dependence on nicotine.
  • Known smoking substitute systems include electronic systems that permit a user to simulate the act of smoking by producing an aerosol (also referred to as a "vapour") that is drawn into the lungs through the mouth (inhaled) and then exhaled.
  • the inhaled aerosol typically bears nicotine and/or a flavourant without, or with fewer of, the health risks associated with conventional smoking.
  • smoking substitute systems are intended to provide a substitute for the rituals of smoking, whilst providing the user with a similar, or improved, experience and satisfaction to those experienced with conventional smoking and with combustible tobacco products.
  • smoking substitute systems have grown rapidly in the past few years. Although originally marketed as an aid to assist habitual smokers wishing to quit tobacco smoking, consumers are increasingly viewing smoking substitute systems as desirable lifestyle accessories. There are a number of different categories of smoking substitute systems, each utilising a different smoking substitute approach. Some smoking substitute systems are designed to resemble a conventional cigarette and are cylindrical in form with a mouthpiece at one end. Other smoking substitute devices do not generally resemble a cigarette (for example, the smoking substitute device may have a generally box-like form, in whole or in part).
  • a vaporisable liquid, or an aerosol former sometimes typically referred to herein as “e-liquid”
  • e-liquid is heated by a heating device (sometimes referred to herein as an electronic cigarette or “e-cigarette” device) to produce an aerosol vapour which is inhaled by a user.
  • the e-liquid typically includes a base liquid, nicotine and may include a flavourant.
  • the resulting vapour therefore also typically contains nicotine and/or a flavourant.
  • the base liquid may include propylene glycol and/or vegetable glycerine.
  • a typical e-cigarette device includes a mouthpiece, a power source (typically a battery), a tank for containing e-liquid and a heating device.
  • a power source typically a battery
  • a tank for containing e-liquid In use, electrical energy is supplied from the power source to the heating device, which heats the e-liquid to produce an aerosol (or "vapour") which is inhaled by a user through the mouthpiece.
  • E-cigarettes can be configured in a variety of ways.
  • there are "closed system" vaping smoking substitute systems which typically have a sealed tank and heating element. The tank is prefilled with e-liquid and is not intended to be refilled by an end user.
  • One subset of closed system vaping smoking substitute systems include a main body which includes the power source, wherein the main body is configured to be physically and electrically couplable to a consumable including the tank and the heating element. In this way, when the tank of a consumable has been emptied of e-liquid, that consumable is removed from the main body and disposed of. The main body can then be reused by connecting it to a new, replacement, consumable.
  • Another subset of closed system vaping smoking substitute systems are completely disposable, and intended for one-use only.
  • vaping smoking substitute systems which typically have a tank that is configured to be refilled by a user. In this way the entire device can be used multiple times.
  • An example vaping smoking substitute system is the mybluTM e-cigarette.
  • the mybluTM e-cigarette is a closed system which includes a main body and a consumable.
  • the main body and consumable are physically and electrically coupled together by pushing the consumable into the main body.
  • the main body includes a rechargeable battery.
  • the consumable includes a mouthpiece and a sealed tank which contains e-liquid.
  • the consumable further includes a heater, which for this device is a heating filament coiled around a portion of a wick. The wick is partially immersed in the e-liquid, and conveys e-liquid from the tank to the heating filament.
  • the system is controlled by a microprocessor on board the main body.
  • the system includes a sensor for detecting when a user is inhaling through the mouthpiece, the microprocessor then activating the device in response.
  • the system When the system is activated, electrical energy is supplied from the power source to the heating device, which heats e-liquid from the tank to produce a vapour which is inhaled by a user through the mouthpiece.
  • the aerosol droplets have a size distribution that is not suitable for delivering nicotine to the lungs. Aerosol droplets of a large particle size tend to be deposited in the mouth and/or upper respiratory tract. Aerosol particles of a small (e.g. sub-micron) particle size can be inhaled into the lungs but may be exhaled without delivering nicotine to the lungs. As a result the user would require drawing a longer puff, more puffs, or vaporising e-liquid with a higher nicotine concentration in order to achieve the desired experience.
  • a factor associated with generating suitable aerosol droplet size distributions in typical smoking substitute systems is considered to be the velocity of air flowing over the heater which generates aerosol droplets.
  • a single air flow passage extends between an air inlet and a mouthpiece with an aerosol generator disposed in the passage.
  • an air flow is generated in the passage that passes over the aerosol generator.
  • the air velocity over the aerosol generator is determined by the inhalation flow rate imposed by the user. As such, if the user inhales too vigorously, the air velocity over the aerosol generator becomes too large to produce aerosol droplets of a suitable size distribution, thus lowering the efficiency of nicotine delivery for the system.
  • the present invention provides a bypass flow passage, permitting division of an air flow between the bypass flow passage and a main flow passage, wherein a flow regulator presents a variable flow resistance to air flow in the bypass passage to vary a proportion of air flow through the bypass flow passage compared with the air flow through the main flow passage.
  • a smoking substitute apparatus comprising:
  • the arrangement of the flow passages allows a flow demanded by a user drawing air through the apparatus, e.g. by inhalation, to be shared between the main and bypass flow passages.
  • a flow demanded by a user drawing air through the apparatus e.g. by inhalation
  • the rate of flow in the main passage, and hence the air velocity over the aerosol generator is lower than a corresponding case where the bypass passage is absent.
  • This is useful in cases where the user inhales with a high flow rate, as it prevents the air velocity over the aerosol generator from becoming too high to generate suitably sized aerosol droplets.
  • the flow regulator provides a further advantage by allowing the proportions of air flow through the bypass flow passage and the main flow passage to be varied according to an air pressure difference across the flow regulator. For example, when a user demands a higher rate of flow, the pressure difference across the flow regulator is higher, and the flow regulator reduces the resistance to air flow through the bypass passage. This decreases the proportion of air flow through the main flow passage, which decreases the velocity of air over the aerosol generator to a suitable level, allowing aerosol droplets of a suitable size distribution to be generated by the aerosol generator. Conversely, when a user demands a lower rate of flow, the pressure difference across the flow regulator is lower, and the flow regulator increases the resistance to air flow through the bypass passage. This increases the proportion of air flow through the main flow passage, which increases the velocity of air over the aerosol generator to a suitable level, again allowing aerosol droplets of a suitable size distribution to be generated by the aerosol generator.
  • the main air inlet and the bypass air inlet may be separate.
  • the main outlet and the bypass outlet may be constituted by a common outlet.
  • the flow regulator may include a resiliently deformable member configured to vary the flow resistance to air flow in the bypass passage by resiliently deforming to a variable extent depending on the air pressure difference across the flow regulator.
  • a resiliently deformable member provides a simple means for varying flow resistance depending on an air pressure difference.
  • the resiliently deformable member can be configured to deform, so as to vary the cross sectional area of flow through the flow regulator, according to the air pressure thereacross.
  • the resiliently deformable member may be an annular member attached circumferentially to an inner wall of the bypass flow passage.
  • the flow regulator may include a member hinged with respect to a wall of the bypass flow passage, the member being configured to vary the flow resistance to air flow in the bypass passage by hinging about the wall of the bypass flow passage so as to vary the cross sectional area of flow through the regulator.
  • the smoking substitute apparatus may further include a mouthpiece having a bypass channel for engaging with the bypass passage so as to be in fluid communication therewith, and a main channel for engaging with the main passage so as to be in fluid communication therewith, wherein at least one flow regulator is situated in the bypass channel of the mouthpiece.
  • the aerosol generator may include a heater.
  • the aerosol precursor may be a liquid.
  • the aerosol generator may operate to vaporise the aerosol precursor using heat generated by the heater, the vapour subsequently forming an aerosol entrained in air flowing along the main passage.
  • the smoking substitute apparatus may be configured to generate an aerosol having a median droplet size, d 50 , of at least 1 ⁇ m.
  • a smoking substitute device configured to engage with the smoking substitute apparatus of the first aspect, wherein the device comprises a controller and a power source configured to energise the aerosol generator.
  • a smoking substitute system for generating an aerosol comprising: the smoking substitute apparatus of the first aspect; and the smoking substitute device of the second aspect.
  • a method of generating an aerosol using the smoking substitute apparatus of the first aspect wherein droplets of the aerosol have a median diameter, d 50 , of at least 1 ⁇ m.
  • the smoking substitute apparatus may be in the form of a consumable.
  • the consumable may be configured for engagement with a main body (the device).
  • the combination of the consumable and the main body may form a smoking substitute system such as a closed smoking substitute system.
  • the consumable may comprise components of the system that are disposable, and the main body may comprise non-disposable or non-consumable components (e.g. sensors, etc.) that facilitate the generation and/or delivery of aerosol by the consumable.
  • the aerosol precursor e.g. e-liquid
  • the smoking substitute apparatus may be a non-consumable apparatus (e.g. that is in the form of an open smoking substitute system).
  • an aerosol former e.g. e-liquid
  • the aerosol precursor may be replenished by re-filling, e.g. a reservoir of the smoking substitute apparatus, with the aerosol precursor (rather than replacing a consumable component of the apparatus).
  • the smoking substitute apparatus may alternatively form part of a main body for engagement with the smoking substitute apparatus. This may be the case in particular when the smoking substitute apparatus is in the form of a consumable.
  • the main body and the consumable may be configured to be physically coupled together.
  • the consumable may be at least partially received in a recess of the main body, such that there is an interference fit between the main body and the consumable.
  • the main body and the consumable may be physically coupled together by screwing one onto the other, or through a bayonet fitting, or the like.
  • the smoking substitute apparatus may comprise one or more engagement portions for engaging with a main body.
  • one end of the smoking substitute apparatus may be coupled with the main body, whilst an opposing end of the smoking substitute apparatus may define a mouthpiece of the smoking substitute system.
  • the smoking substitute apparatus may comprise a reservoir configured to store the aerosol precursor, such as an e-liquid.
  • the e-liquid may, for example, comprise a base liquid.
  • the e-liquid may further comprise nicotine.
  • the base liquid may include propylene glycol and/or vegetable glycerine.
  • the e-liquid may be substantially flavourless. That is, the e-liquid may not contain any deliberately added additional flavourant and may consist solely of a base liquid of propylene glycol and/or vegetable glycerine and nicotine.
  • the reservoir may be in the form of a tank. At least a portion of the tank may be light-transmissive.
  • the tank may comprise a window to allow a user to visually assess the quantity of e-liquid in the tank.
  • a housing of the smoking substitute apparatus may comprise a corresponding aperture (or slot) or window that may be aligned with a light-transmissive portion (e.g. window) of the tank.
  • the reservoir may be referred to as a "clearomizer” if it includes a window, or a "cartomizer” if it does not.
  • the main and/or bypass outlets may be at a mouthpiece of the smoking substitute apparatus.
  • a user may draw fluid (e.g. air) into and through the main and/or bypass passages by inhaling at the main and/or bypass outlets (e.g. using the mouthpiece).
  • the main and/or bypass passages may be at least partially defined by the tank.
  • the tank may substantially (or fully) define the main and/or bypass passages, for at least a part of the length of the respective passage.
  • the tank may surround the main and/or bypass passages, e.g. in an annular arrangement around the respective passage.
  • the aerosol generator may comprise a wick.
  • the aerosol generator may further comprise a heater.
  • the wick may comprise a porous material, capable of wicking the aerosol precursor. A portion of the wick may be exposed to air flow in the passage.
  • the wick may also comprise one or more portions in contact with liquid stored in the reservoir. For example, opposing ends of the wick may protrude into the reservoir and an intermediate portion (between the ends) may extend across the passage so as to be exposed to air flow in the passage. Thus, liquid may be drawn (e.g. by capillary action) along the wick, from the reservoir to the portion of the wick exposed to air flow.
  • the heater may comprise a heating element, which may be in the form of a filament wound about the wick (e.g. the filament may extend helically about the wick in a coil configuration).
  • the heating element may be wound about the intermediate portion of the wick that is exposed to air flow in the main flow passage.
  • the heating element may be electrically connected (or connectable) to a power source.
  • the power source may apply a voltage across the heating element so as to heat the heating element by resistive heating. This may cause liquid stored in the wick (i.e. drawn from the tank) to be heated so as to form a vapour and become entrained in air flowing through the main flow passage. This vapour may subsequently cool to form an aerosol in the main flow passage, typically downstream from the heating element.
  • the smoking substitute apparatus may comprise a vaporisation chamber.
  • the vaporisation chamber may form part of the main flow passage in which the heater is located.
  • the vaporisation chamber may be arranged to be in fluid communication with the main air inlet and the main air outlet.
  • the vaporisation chamber may be an enlarged portion of the main flow passage.
  • the air as drawn in by the user may entrain the generated vapour in a flow away from heater.
  • the entrained vapour may form an aerosol in the vaporisation chamber, or it may form the aerosol further downstream along the main flow passage.
  • the vaporisation chamber may be at least partially defined by the tank.
  • the tank may substantially (or fully) define the vaporisation chamber. In this respect, the tank may surround the vaporisation chamber, e.g. in an annular arrangement around the vaporisation chamber.
  • the user may puff on a mouthpiece of the smoking substitute apparatus, i.e. draw on the smoking substitute apparatus by inhaling, to draw in an air stream therethrough.
  • a portion, or all, of the air stream (also referred to as a "main air flow”) may pass through the vaporisation chamber so as to entrain the vapour generated at the heater. That is, such a main air flow may be heated by the heater (although typically only to a limited extent) as it passes through the vaporisation chamber.
  • the aerosol droplets may be delivered to and be absorbed at a target delivery site, e.g. a user's lung, whilst a portion of the aerosol droplets may instead adhere onto other parts of the user's respiratory tract, e.g. the user's oral cavity and/or throat.
  • the aerosol droplets as measured at the outlets of their respective passages, e.g. at the mouthpieces may have a median droplet size, d 50 , of less than 1 ⁇ m.
  • the d 50 particle size of the aerosol particles is preferably at least 1 ⁇ m.
  • the d 50 particle size is not more than 10 ⁇ m, preferably not more than 9 ⁇ m, not more than 8 ⁇ m, not more than 7 ⁇ m, not more than 6 ⁇ m, not more than 5 ⁇ m, not more than 4 ⁇ m or not more than 3 ⁇ m. It is considered that providing aerosol particle sizes in such ranges permits improved interaction between the aerosol particles and the user's lungs.
  • the median particle droplet sizes, d 50 of an aerosol may be measured by a laser diffraction technique.
  • the stream of aerosol output from the main air outlet may be drawn through a Malvern Spraytec laser diffraction system, where the intensity and pattern of scattered laser light are analysed to calculate the size and size distribution of aerosol droplets.
  • the particle size distribution may be expressed in terms of d 10 , d 50 and d 90 , for example.
  • the d 10 particle size is the particle size below which 10% by volume of the sample lies.
  • the d 50 particle size is the particle size below which 50% by volume of the sample lies.
  • the d 90 particle size is the particle size below which 90% by volume of the sample lies.
  • the particle size measurements are volume-based particle size measurements, rather than number-based or mass-based particle size measurements.
  • the spread of particle size may be expressed in terms of the span, which is defined as (d 90 -d 10 )/d 50 .
  • the span is not more than 20, preferably not more than 10, preferably not more than 8, preferably not more than 4, preferably not more than 2, preferably not more than 1, or not more than 0.5.
  • the smoking substitute apparatus may comprise a power source.
  • the power source of the apparatus or the main body, may be electrically connected (or connectable) to a heater of the smoking substitute apparatus (e.g. when the smoking substitute apparatus is engaged with the main body).
  • the power source may be a battery (e.g. a rechargeable battery).
  • a connector in the form of e.g. a USB port may be provided for recharging this battery.
  • the smoking substitute apparatus When the smoking substitute apparatus is in the form of a consumable, the smoking substitute apparatus may comprise an electrical interface for interfacing with a corresponding electrical interface of the main body.
  • One or both of the electrical interfaces may include one or more electrical contacts.
  • the electrical interface of the main body when the main body is engaged with the consumable, the electrical interface of the main body may be configured to transfer electrical power from the power source to a heater of the consumable via the electrical interface of the consumable.
  • the electrical interface of the smoking substitute apparatus may also be used to identify the smoking substitute apparatus (in the form of a consumable) from a list of known types.
  • the consumable may have a certain concentration of nicotine and the electrical interface may be used to identify this.
  • the electrical interface may additionally or alternatively be used to identify when a consumable is connected to the main body.
  • the smoking substitute apparatus comprise a controller, which may include a microprocessor.
  • the controller of the apparatus or the main body may be configured to control the supply of power from the power source to the heater of the smoking substitute apparatus (e.g. via the electrical contacts).
  • a memory may be provided and may be operatively connected to the controller.
  • the memory may include non-volatile memory.
  • the memory may include instructions which, when implemented, cause the controller to perform certain tasks or steps of a method.
  • the main body or smoking substitute apparatus may comprise a wireless interface, which may be configured to communicate wirelessly with another device, for example a mobile device, e.g. via Bluetooth®.
  • the wireless interface could include a Bluetooth® antenna.
  • Other wireless communication interfaces, e.g. WiFi®, are also possible.
  • the wireless interface may also be configured to communicate wirelessly with a remote server.
  • a puff sensor may be provided that is configured to detect a puff (i.e. inhalation from a user).
  • the puff sensor may be operatively connected to the controller so as to be able to provide a signal to the controller that is indicative of a puff state (i.e. puffing or not puffing).
  • the puff sensor may, for example, be in the form of a pressure sensor or an acoustic sensor. That is, the controller may control power supply to the heater of the consumable in response to a puff detection by the sensor. The control may be in the form of activation of the heater in response to a detected puff. That is, the smoking substitute apparatus may be configured to be activated when a puff is detected by the puff sensor.
  • the puff sensor When the smoking substitute apparatus is in the form of a consumable, the puff sensor may be provided in the consumable or alternatively may be provided in the main body.
  • flavourant is used to describe a compound or combination of compounds that provide flavour and/or aroma.
  • the flavourant may be configured to interact with a sensory receptor of a user (such as an olfactory or taste receptor).
  • the flavourant may include one or more volatile substances.
  • the flavourant may be provided in solid or liquid form.
  • the flavourant may be natural or synthetic.
  • the flavourant may include menthol, liquorice, chocolate, fruit flavour (including e.g. citrus, cherry etc.), vanilla, spice (e.g. ginger, cinnamon) and tobacco flavour.
  • the flavourant may be evenly dispersed or may be provided in isolated locations and/or varying concentrations.
  • the present inventors consider that a flow rate of 1.3 L min -1 is towards the lower end of a typical user expectation of flow rate through a conventional cigarette and therefore through a user-acceptable smoking substitute apparatus.
  • the present inventors further consider that a flow rate of 2.0 L min -1 is towards the higher end of a typical user expectation of flow rate through a conventional cigarette and therefore through a user-acceptable smoking substitute apparatus.
  • Embodiments of the present invention therefore provide an aerosol with advantageous particle size characteristics across a range of flow rates of air through the apparatus.
  • the aerosol may have a Dv50 of at least 1.1 ⁇ m, at least 1.2 ⁇ m, at least 1.3 ⁇ m, at least 1.4 ⁇ m, at least 1.5 ⁇ m, at least 1.6 ⁇ m, at least 1.7 ⁇ m, at least 1.8 ⁇ m, at least 1.9 ⁇ m or at least 2.0 ⁇ m.
  • the aerosol may have a Dv50 of not more than 4.9 ⁇ m, not more than 4.8 ⁇ m, not more than 4.7 ⁇ m, not more than 4.6 ⁇ m, not more than 4.5 ⁇ m, not more than 4.4 ⁇ m, not more than 4.3 ⁇ m, not more than 4.2 ⁇ m, not more than 4.1 ⁇ m, not more than 4.0 ⁇ m, not more than 3.9 ⁇ m, not more than 3.8 ⁇ m, not more than 3.7 ⁇ m, not more than 3.6 ⁇ m, not more than 3.5 ⁇ m, not more than 3.4 ⁇ m, not more than 3.3 ⁇ m, not more than 3.2 ⁇ m, not more than 3.1 ⁇ m or not more than 3.0 ⁇ m.
  • a particularly preferred range for Dv50 of the aerosol is in the range 2-3 ⁇ m.
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that, when the air flow rate inhaled by the user through the apparatus is 1.3 L min -1 , the average magnitude of velocity of air in the vaporisation chamber is in the range 0-1.3 ms -1 .
  • the average magnitude velocity of air may be calculated based on knowledge of the geometry of the vaporisation chamber and the flow rate.
  • the average magnitude of velocity of air in the vaporisation chamber may be at least 0.001 ms -1 , or at least 0.005 ms -1 , or at least 0.01 ms -1 , or at least 0.05 ms -1 .
  • the average magnitude of velocity of air in the vaporisation chamber may be at most 1.2 ms -1 , at most 1.1 ms -1 , at most 1.0 ms -1 , at most 0.9 ms -1 , at most 0.8 ms -1 , at most 0.7 ms -1 or at most 0.6 ms -1 .
  • the average magnitude of velocity of air in the vaporisation chamber may be at least 0.001 ms -1 , or at least 0.005 ms -1 , or at least 0.01 ms -1 , or at least 0.05 ms -1 .
  • the average magnitude of velocity of air in the vaporisation chamber may be at most 1.2 ms -1 , at most 1.1 ms -1 , at most 1.0 ms -1 , at most 0.9 ms -1 , at most 0.8 ms -1 , at most 0.7 ms -1 or at most 0.6 ms -1 .
  • the resultant aerosol particle size is advantageously controlled to be in a desirable range. It is further considered that the configuration of the apparatus can be selected so that the average magnitude of velocity of air in the vaporisation chamber can be brought within the ranges specified, at the exemplary flow rate of 1.3 L min -1 and/or the exemplary flow rate of 2.0 L min -1 .
  • the aerosol generator may comprise a vaporiser element loaded with aerosol precursor, the vaporiser element being heatable by a heater and presenting a vaporiser element surface to air in the vaporisation chamber.
  • a vaporiser element region may be defined as a volume extending outwardly from the vaporiser element surface to a distance of 1 mm from the vaporiser element surface.
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that, when the air flow rate inhaled by the user through the apparatus is 1.3 L min -1 , the average magnitude of velocity of air in the vaporiser element region is in the range 0-1.2 ms -1 .
  • the average magnitude of velocity of air in the vaporiser element region may be calculated using computational fluid dynamics.
  • the average magnitude of velocity of air in the vaporiser element region may be at least 0.001 ms -1 , or at least 0.005 ms -1 , or at least 0.01 ms -1 , or at least 0.05 ms -1 .
  • the average magnitude of velocity of air in the vaporiser element region may be at most 1.1 ms -1 , at most 1.0 ms -1 , at most 0.9 ms -1 , at most 0.8 ms -1 , at most 0.7 ms -1 or at most 0.6 ms -1 .
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that, when the air flow rate inhaled by the user through the apparatus is 2.0 L min -1 , the average magnitude of velocity of air in the vaporiser element region is in the range 0-1.2 ms -1 .
  • the average magnitude of velocity of air in the vaporiser element region may be calculated using computational fluid dynamics.
  • the average magnitude of velocity of air in the vaporiser element region may be at most 1.1 ms -1 , at most 1.0 ms -1 , at most 0.9 ms -1 , at most 0.8 ms -1 , at most 0.7 ms -1 or at most 0.6 ms -1 .
  • the resultant aerosol particle size is advantageously controlled to be in a desirable range. It is further considered that the velocity of air in the vaporiser element region is more relevant to the resultant particle size characteristics than consideration of the velocity in the vaporisation chamber as a whole. This is in view of the significant effect of the velocity of air in the vaporiser element region on the cooling of the vapour emitted from the vaporiser element surface.
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that, when the air flow rate inhaled by the user through the apparatus is 1.3 L min -1 , the maximum magnitude of velocity of air in the vaporiser element region is in the range 0-2.0 ms -1 .
  • the maximum magnitude of velocity of air in the vaporiser element region may be at least 0.001 ms -1 , or at least 0.005 ms -1 , or at least 0.01 ms -1 , or at least 0.05 ms -1 .
  • the maximum magnitude of velocity of air in the vaporiser element region may be at most 1.9 ms -1 , at most 1.8 ms -1 , at most 1.7 ms -1 , at most 1.6 ms -1 , at most 1.5 ms -1 , at most 1.4 ms -1 , at most 1.3 ms -1 or at most 1.2 ms -1 .
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that, when the air flow rate inhaled by the user through the apparatus is 2.0 L min -1 , the maximum magnitude of velocity of air in the vaporiser element region is in the range 0-2.0 ms -1 .
  • the maximum magnitude of velocity of air in the vaporiser element region may be at least 0.001 ms -1 , or at least 0.005 ms -1 , or at least 0.01 ms -1 , or at least 0.05 ms -1 .
  • the maximum magnitude of velocity of air in the vaporiser element region may be at most 1.9 ms -1 , at most 1.8 ms -1 , at most 1.7 ms -1 , at most 1.6 ms -1 , at most 1.5 ms -1 , at most 1.4 ms -1 , at most 1.3 ms -1 or at most 1.2 ms -1 .
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that, when the air flow rate inhaled by the user through the apparatus is 1.3 L min -1 , the turbulence intensity in the vaporiser element region is not more than 1%.
  • the turbulence intensity in the vaporiser element region may be not more than 0.95%, not more than 0.9%, not more than 0.85%, not more than 0.8%, not more than 0.75%, not more than 0.7%, not more than 0.65% or not more than 0.6%.
  • the particle size characteristics of the generated aerosol may be determined by the cooling rate experienced by the vapour after emission from the vaporiser element (e.g. wick).
  • the vaporiser element e.g. wick
  • imposing a relatively slow cooling rate on the vapour has the effect of generating aerosols with a relatively large particle size.
  • the parameters discussed above are considered to be mechanisms for implementing a particular cooling dynamic to the vapour.
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that a desired cooling rate is imposed on the vapour.
  • the particular cooling rate to be used depends of course on the nature of the aerosol precursor and other conditions. However, for a particular aerosol precursor it is possible to define a set of testing conditions in order to define the cooling rate, and by extension this imposes limitations on the configuration of the apparatus to permit such cooling rates as are shown to result in advantageous aerosols.
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that the cooling rate of the vapour is such that the time taken to cool to 50 °C is not less than 16 ms, when tested according to the following protocol.
  • the aerosol precursor is an e-liquid consisting of 1.6% freebase nicotine and the remainder a 65:35 propylene glycol and vegetable glycerine mixture, the e-liquid having a boiling point of 209 °C.
  • Air is drawn into the air inlet at a temperature of 25 °C.
  • the vaporiser is operated to release a vapour of total particulate mass 5 mg over a 3 second duration from the vaporiser element surface in an air flow rate between the air inlet and outlet of 1.3 L min -1 .
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that the cooling rate of the vapour is such that the time taken to cool to 50 °C is not less than 16 ms, when tested according to the following protocol.
  • the aerosol precursor is an e-liquid consisting of 1.6% freebase nicotine and the remainder a 65:35 propylene glycol and vegetable glycerine mixture, the e-liquid having a boiling point of 209 °C.
  • Air is drawn into the air inlet at a temperature of 25 °C.
  • the vaporiser is operated to release a vapour of total particulate mass 5 mg over a 3 second duration from the vaporiser element surface in an air flow rate between the air inlet and outlet of 2.0 L min -1 .
  • the equivalent linear cooling rate of the vapour to 50 °C may be not more than 9 °C/ms, not more than 8 °C/ms, not more than 7 °C/ms, not more than 6 °C/ms or not more than 5 °C/ms.
  • Cooling of the vapour such that the time taken to cool to 50 °C is not less than 32 ms corresponds to an equivalent linear cooling rate of not more than 5 °C/ms.
  • the testing protocol set out above considers the cooling of the vapour (and subsequent aerosol) to a temperature of 50 °C. This is a temperature which can be considered to be suitable for an aerosol to exit the apparatus for inhalation by a user without causing significant discomfort. It is also possible to consider cooling of the vapour (and subsequent aerosol) to a temperature of 75 °C. Although this temperature is possibly too high for comfortable inhalation, it is considered that the particle size characteristics of the aerosol are substantially settled by the time the aerosol cools to this temperature (and they may be settled at still higher temperature).
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that the cooling rate of the vapour is such that the time taken to cool to 75 °C is not less than 4.5 ms, when tested according to the following protocol.
  • the aerosol precursor is an e-liquid consisting of 1.6% freebase nicotine and the remainder a 65:35 propylene glycol and vegetable glycerine mixture, the e-liquid having a boiling point of 209 °C.
  • Air is drawn into the air inlet at a temperature of 25 °C.
  • the vaporiser is operated to release a vapour of total particulate mass 5 mg over a 3 second duration from the vaporiser element surface in an air flow rate between the air inlet and outlet of 1.3 L min -1 .
  • the air inlet, flow passage, outlet and the vaporisation chamber may be configured so that the cooling rate of the vapour is such that the time taken to cool to 75 °C is not less than 4.5 ms, when tested according to the following protocol.
  • the aerosol precursor is an e-liquid consisting of 1.6% freebase nicotine and the remainder a 65:35 propylene glycol and vegetable glycerine mixture, the e-liquid having a boiling point of 209 °C.
  • Air is drawn into the air inlet at a temperature of 25 °C.
  • the vaporiser is operated to release a vapour of total particulate mass 5 mg over a 3 second duration from the vaporiser element surface in an air flow rate between the air inlet and outlet of 2.0 L min -1 .
  • the equivalent linear cooling rate of the vapour to 75 °C may be not more than 29 °C/ms, not more than 28 °C/ms, not more than 27 °C/ms, not more than 26 °C/ms, not more than 25 °C/ms, not more than 24 °C/ms, not more than 23 °C/ms, not more than 22 °C/ms, not more than 21 °C/ms, not more than 20 °C/ms, not more than 19 °C/ms, not more than 18 °C/ms, not more than 17 °C/ms, not more than 16 °C/ms, not more than 15 °C/ms, not more than 14 °C/ms, not more than 13 °C/ms, not more than 12 °C/ms, not more than 11 °C/ms or not more than 10 °C/ms.
  • Cooling of the vapour such that the time taken to cool to 75 °C is not less than 13 ms corresponds to an equivalent linear cooling rate of not more than 10 °C/ms.
  • the invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.
  • FIGS 17 and 18 illustrate a smoking substitute system in the form of an e-cigarette system 110.
  • the system 110 comprises a main body 120 of the system 110, and a smoking substitute apparatus in the form of an e-cigarette consumable (or "pod") 150.
  • the consumable 150 (sometimes referred to herein as a smoking substitute apparatus) is removable from the main body 120, so as to be a replaceable component of the system 110.
  • the e-cigarette system 110 is a closed system in the sense that it is not intended that the consumable should be refillable with e-liquid by a user.
  • the consumable 150 is configured to engage the main body 120.
  • Figure 17 shows the main body 120 and the consumable 150 in an engaged state
  • Figure 18 shows the main body 120 and the consumable 150 in a disengaged state.
  • a portion of the consumable 150 is received in a cavity of corresponding shape in the main body 120 and is retained in the engaged position by way of a snap-engagement mechanism.
  • the main body 120 and consumable 150 may be engaged by screwing one into (or onto) the other, or through a bayonet fitting, or by way of an interference fit.
  • the system 110 is configured to vaporise an aerosol precursor, which in the illustrated embodiment is in the form of a nicotine-based e-liquid 160.
  • the e-liquid 160 comprises nicotine and a base liquid including propylene glycol and/or vegetable glycerine.
  • the e-liquid 160 is flavoured by a flavourant.
  • the e-liquid 160 may be flavourless and thus may not include any added flavourant.
  • FIG 19 shows a schematic longitudinal cross sectional view of a reference arrangement of the smoking substitute apparatus forming part of the smoking substitute system shown in Figures 17 and 18 .
  • the e-liquid 160 is stored within a reservoir in the form of a tank 152 that forms part of the consumable 150.
  • the consumable 150 is a "single-use" consumable 150. That is, upon exhausting the e-liquid 160 in the tank 152, the intention is that the user disposes of the entire consumable 150.
  • the term "single-use" does not necessarily mean the consumable is designed to be disposed of after a single smoking session.
  • the tank may include a vent (not shown) to allow ingress of air to replace e-liquid that has been used from the tank.
  • the consumable 150 preferably includes a window 158 (see Figures 17 and 18 ), so that the amount of e-liquid in the tank 152 can be visually assessed.
  • the main body 120 includes a slot 157 so that the window 158 of the consumable 150 can be seen whilst the rest of the tank 152 is obscured from view when the consumable 150 is received in the cavity of the main body 120.
  • the consumable 150 may be referred to as a "clearomizer” when it includes a window 158, or a "cartomizer” when it does not.
  • the e-liquid i.e. aerosol precursor
  • the tank may be refillable with e-liquid or the e-liquid may be stored in a non-consumable component of the system.
  • the e-liquid may be stored in a tank located in the main body or stored in another component that is itself not single-use (e.g. a refillable cartomizer).
  • the external wall of tank 152 is provided by a casing of the consumable 150.
  • the tank 152 annularly surrounds, and thus defines a portion of, a passage 170 that extends between a vaporiser inlet 172 and an outlet 174 at opposing ends of the consumable 150.
  • the passage 170 comprises an upstream end at the end of the consumable 150 that engages with the main body 120, and a downstream end at an opposing end of the consumable 150 that comprises a mouthpiece 154 of the system 110.
  • a plurality of device air inlets 176 are formed at the boundary between the casing of the consumable and the casing of the main body.
  • the device air inlets 176 are in fluid communication with the vaporiser inlet 172 through an inlet flow channel 178 formed in the cavity of the main body which is of corresponding shape to receive a part of the consumable 150. Air from outside of the system 110 can therefore be drawn into the passage 170 through the device air inlets 176 and the inlet flow channels 178.
  • the passage 170 may be partially defined by a tube (e.g. a metal tube) extending through the consumable 150.
  • the passage 170 is shown with a substantially circular cross-sectional profile with a constant diameter along its length.
  • the passage may have other cross-sectional profiles, such as oval shaped or polygonal shaped profiles.
  • the cross sectional profile and the diameter (or hydraulic diameter) of the passage may vary along its longitudinal axis.
  • the smoking substitute system 110 is configured to vaporise the e-liquid 160 for inhalation by a user.
  • the consumable 150 comprises a heater having a porous wick 162 and a resistive heating element in the form of a heating filament 164 that is helically wound (in the form of a coil) around a portion of the porous wick 162.
  • the porous wick 162 extends across the passage 170 (i.e. transverse to a longitudinal axis of the passage 170 and thus also transverse to the air flow along the passage 170 during use) and opposing ends of the wick 162 extend into the tank 152 (so as to be immersed in the e-liquid 160). In this way, e-liquid 160 contained in the tank 152 is conveyed from the opposing ends of the porous wick 162 to a central portion of the porous wick 162 so as to be exposed to the airflow in the passage 170.
  • the helical filament 164 is wound about the exposed central portion of the porous wick 162 and is electrically connected to an electrical interface in the form of electrical contacts 156 mounted at the end of the consumable that is proximate the main body 120 (when the consumable and the main body are engaged).
  • electrical contacts 156 make contact with corresponding electrical contacts (not shown) of the main body 120.
  • the main body electrical contacts are electrically connectable to a power source (not shown) of the main body 120, such that (in the engaged position) the filament 164 is electrically connectable to the power source. In this way, power can be supplied by the main body 120 to the filament 164 in order to heat the filament 164.
  • FIG 20 illustrates in more detail the vaporisation chamber and therefore the region of the consumable 150 around the wick 162 and filament 164.
  • the helical filament 164 is wound around a central portion of the porous wick 162.
  • the porous wick extends across passage 170.
  • E-liquid 160 contained within the tank 152 is conveyed as illustrated schematically by arrows 401, i.e. from the tank and towards the central portion of the porous wick 162.
  • porous wick 162 When the user inhales, air is drawn from through the inlets 176 shown in Figure 19 , along inlet flow channel 178 to vaporisation chamber inlet 172 and into the vaporisation chamber containing porous wick 162.
  • the porous wick 162 extends substantially transverse to the airflow direction.
  • the airflow passes around the porous wick, at least a portion of the airflow substantially following the surface of the porous wick 162.
  • the airflow may follow a curved path around an outer periphery of the porous wick 162.
  • the filament 164 is heated so as to vaporise the e-liquid which has been wicked into the porous wick.
  • the airflow passing around the porous wick 162 picks up this vaporised e-liquid, and the vapour-containing airflow is drawn in direction 403 further down passage 170.
  • the power source of the main body 120 may be in the form of a battery (e.g. a rechargeable battery such as a lithium ion battery).
  • the main body 120 may comprise a connector in the form of e.g. a USB port for recharging this battery.
  • the main body 120 may also comprise a controller that controls the supply of power from the power source to the main body electrical contacts (and thus to the filament 164). That is, the controller may be configured to control a voltage applied across the main body electrical contacts, and thus the voltage applied across the filament 164. In this way, the filament 164 may only be heated under certain conditions (e.g. during a puff and/or only when the system is in an active state).
  • the main body 120 may include a puff sensor (not shown) that is configured to detect a puff (i.e. inhalation).
  • the puff sensor may be operatively connected to the controller so as to be able to provide a signal, to the controller, which is indicative of a puff state (i.e. puffing or not puffing).
  • the puff sensor may, for example, be in the form of a pressure sensor or an acoustic sensor.
  • the main body 120 and consumable 150 may comprise a further interface which may, for example, be in the form of an RFID reader, a barcode or QR code reader.
  • This interface may be able to identify a characteristic (e.g. a type) of a consumable 150 engaged with the main body 120.
  • the consumable 150 may include anyone or more of an RFID chip, a barcode or QR code, or memory within which is an identifier and which can be interrogated via the interface.
  • Figure 21 illustrates a smoking substitute apparatus 250 according to an embodiment of the invention.
  • Components and parts of the apparatus that are common to the reference arrangement of Figure 19 are referenced with the same number, and are not discussed further in view of this embodiment.
  • the smoking substitute apparatus of the present embodiment differs from that of the reference arrangement in that it includes bypass air flow passages 200 which extend from bypass air inlets 201 to bypass air outlets 202.
  • the bypass passages 200 are defined by the casing of the consumable and are located towards the outlet end of the apparatus 250.
  • the bypass passages 200 may be disposed in a different part of the consumable, such as coaxially adjacent to the passage 170 (hereinafter referred to as the "main flow passage") or through the tank 152.
  • FIG. 22a to 22c An exemplary flow regulator 213a is illustrated in Figures 22a to 22c .
  • the flow regulator 213a is an annular member made of a resiliently deformable material, providing an aperture with an adjustable size.
  • the regulator 213a may be made from a silicon based material having a tailored Shore hardness.
  • the range of adjustable sizes of the aperture does not exceed the cross sectional area of the bypass passage 200.
  • the regulator 213a provides an increased air flow resistance in the bypass passage 200 compared to a corresponding case in which the flow regulator 213a is absent.
  • Figure 22a shows the flow regulator 213a disposed in a bypass flow passage 200 in a schematic arrangement, the flow regulator 213a being attached circumferentially to an inner wall of the bypass flow passage 200.
  • the aperture is constricted (relaxed) or dilates according to the air pressure difference across the flow regulator 213a. Specifically, when the velocity of air flow through the bypass passage 200 is high, the pressure difference is correspondingly high, and the aperture dilates so as to decrease the resistance to air flow in the bypass passage 200.
  • the aperture constricts (relaxes) to a small size so as to provide a high resistance to air flow. Accordingly, when a user draws air from the apparatus with a high inhalation flow rate, air velocity through the bypass flow passage 200 is high, and the flow regulator 213a decreases resistance to air flow so as to allow a greater air flow rate in the bypass flow passage 200, thus reducing the proportion of air flow which passes through the main flow passage 170. Similarly, when the inhalation rate is low, the flow regulator provides a high air flow resistance in the bypass passage 200, thus allowing a large proportion of air flow to flow through the main flow passage 170.
  • a suitable size distribution may be characterised by a median droplet size, d 50 , of at least 1 ⁇ m, more preferably d 50 is in the range 2-3 ⁇ m.
  • Figure 22b shows a longitudinal cross section of the bypass flow passage 200 and the flow regulator 213a.
  • This view illustrates one suitable mechanism for how the flow regulator 213a dilates and constricts when subjected to a pressure difference thereacross caused by air flowing through the bypass flow passage 200.
  • air flows along the passage 200 (illustrated by the dashed arrow)
  • air pushes the free, radially inward portion of the member along the direction of flow.
  • the attached, radially outward portion of the member remains attached to the bypass passage 200 and does not move relative to the passage 200.
  • the combination of these responses causes the member 213a to resiliently deform, as shown by the dotted lines in Figure 22b , and therefore dilate the aperture and decrease the resistance to air flow in the passage 200.
  • the cross section of the flow regulator is triangular so that the radially inward portion is thinner than the outward portion and hence the member 213a is more readily deformable at a typical inhalation air flow rate than a corresponding, thicker member. If the rate of air flow is lowered, the radially inward portion moves back towards its original position, so as to constrict the aperture.
  • the member 213a in both constricted and dilated forms is illustrated in Figure 22c .
  • FIG. 23 An alternative example of a flow regulator 213b is shown in Figure 23 .
  • the flow regulator 213b is hinged about a point on a wall of the bypass flow passage 200. By rotating about the point as indicated in Figure 23 (dotted lines), the flow regulator 200 can vary the cross sectional area of air flow through the regulator, which correspondingly varies the resistance to air flow through the bypass flow passage 200.
  • the regulator 213b varies resistance to air flow according to the pressure difference thereacross. For example, air flowing through the bypass flow passage 200 exerts a torque on the flow regulator 213b.
  • the torque may cause the regulator 213b to hinge about the point so as to increase the cross sectional area of flow through the regulator and decrease resistance to air flow in the passage 200.
  • the flow regulator In the absence of such a torque, i.e. when the flow rate of air through the passage 200 is too low, the flow regulator remains at or returns to a high resistance position (e.g. completely blocking the passage). This may be achieved by a coiled spring attached to the flow regulator 213b which exerts a torque opposite to that caused by air flowing through the passage 200.
  • the regulator may be weighted so as to return to a high resistance position under the force of gravity. Indeed, any means of biasing the regulator to a high resistance position may be used.
  • Figure 24 illustrates the apparatus 250 of Figure 21 with the inclusion of a mouthpiece 210.
  • the mouthpiece 210 comprises bypass channels 211 and a main channel 212, for engagement with the bypass air flow passages 200 and the main flow passage 170 respectively.
  • the apparatus of Figure 24 also differs from that of Figure 21 in that the flow regulators 213 are disposed in the bypass channels 211 of the mouthpiece 210.
  • the mouthpiece is removable from the apparatus 250, though in other embodiments the mouthpiece may be fixed to the apparatus. Having the flow regulators 213 disposed in the mouthpiece 210 allows mouthpieces to be tailored with specific regulators 213 to the requirements of individual users or groups of users.
  • a user with a large inhalation flow rate may choose a mouthpiece with a flow regulator 213 which readily lowers the resistance to flow in the bypass passages 200
  • a user with a small inhalation flow rate may choose a mouthpiece with a flow regulator 213 which less readily lowers the resistance to flow in the bypass passages 200.
  • the mouthpiece of Figure 24 including the flow regulators 213, is illustrated more clearly in enlarged form in Figure 25 .
  • Aerosol droplet size is a considered to be an important characteristic for smoking substitution devices. Droplets in the range of 2-5 ⁇ m are preferred in order to achieve improved nicotine delivery efficiency and to minimise the hazard of second-hand smoking. However, at the time of writing (September 2019), commercial EVP devices typically deliver aerosols with droplet size averaged around 0.5 ⁇ m, and to the knowledge of the inventors not a single commercially available device can deliver an aerosol with an average particle size exceeding 1 ⁇ m.
  • the present inventors speculate, without themselves wishing to be bound by theory, that there has to date been a lack of understanding in the mechanisms of e-liquid evaporation, nucleation and droplet growth in the context of aerosol generation in smoking substitute devices. The present inventors have therefore studied these issues in order to provide insight into mechanisms for the generation of aerosols with larger particles. The present inventors have carried out experimental and modelling work alongside theoretical investigations, leading to significant achievements as now reported.
  • This disclosure considers the roles of air velocity, air turbulence and vapour cooling rate in affecting aerosol particle size.
  • a Malvern PANalytical Spraytec laser diffraction system was employed for the particle size measurement.
  • the same coil and wick 1.5 ohms Ni-Cr coil, 1.8 mm Y07 cotton wick
  • Y07 represents the grade of cotton wick, meaning that the cotton has a linear density of 0.7 grams per meter.
  • Particle sizes were measured in accordance with ISO 13320:2009(E), which is an international standard on laser diffraction methods for particle size analysis. This is particularly well suited to aerosols, because there is an assumption in this standard that the particles are spherical (which is a good assumption for liquid-based aerosols). The standard is stated to be suitable for particle sizes in the range 0.1 micron to 3 mm.
  • Figure 2 shows a schematic perspective longitudinal cross sectional view of an example rectangular tube 1170 with a wick 1162 and heater coil 1164 installed.
  • the location of the wick is about half way along the length of the tube. This is intended to allow the flow of air along the tube to settle before reaching the wick.
  • Figure 3 shows a schematic transverse cross sectional view an example rectangular tube 1170 with a wick 1162 and heater coil 1164 installed.
  • the internal width of the tube is 12 mm
  • the rectangular tubes were manufactured to have same internal depth of 6 mm in order to accommodate the standardized coil and wick, however the tube internal width varied from 4.5 mm to 50 mm.
  • the "tube size” is referred to as the internal width of rectangular tubes.
  • the rectangular tubes with different dimensions were used to generate aerosols that were tested for particle size in a Malvern PANalytical Spraytec laser diffraction system.
  • An external digital power supply was dialled to 2.6A constant current to supply 10W power to the heater coil in all experiments. Between two runs, the wick was saturated manually by applying one drop of e-liquid on each side of the wick.
  • Table 1 shows a list of experiments in this study.
  • the values in "calculated air velocity” column were obtained by simply dividing the flow rate by the intersection area at the centre plane of wick.
  • Turbulence intensity was introduced as a quantitative parameter to assess the level of turbulence. The definition and simulation of turbulence intensity is discussed below (see section 3.2).
  • Figures 4A-4D show air flow streamlines in the four devices used in this turbulence study.
  • Figure 4A is a standard 12mm rectangular tube with wick and coil installed as explained in the previous section, with no jetting panel.
  • Figure 4B has a jetting panel located 10mm below (upstream from) the wick.
  • Figure 4C has the same jetting panel 5mm below the wick.
  • Figure 4D has the same jetting panel 2.5mm below the wick.
  • the jetting panel has an arrangement of apertures shaped and directed in order to promote jetting from the downstream face of the panel and therefore to promote turbulent flow.
  • the jetting panel can introduce turbulence downstream, and the panel causes higher level of turbulence near the wick when it is positioned closer to the wick.
  • the four geometries gave turbulence intensities of 0.55%, 0.77%, 1.06% and 1.34%, respectively, with Figure 4A being the least turbulent, and Figure 4D being the most turbulent.
  • the experimental set up is shown in Figure 5 .
  • the testing used a Carbolite Gero EHA 12300B tube furnace 3210 with a quartz tube 3220 to heat up the air. Hot air in the tube furnace was then led into a transparent housing 3158 that contains the EVP device 3150 to be tested.
  • a thermocouple meter 3410 was used to assess the temperature of the air pulled into the EVP device. Once the EVP device was activated, the aerosol was pulled into the Spraytec laser diffraction system 3310 via a silicone connector 3320 for particle size measurement.
  • pod 1 is the commercially available "myblu optimised" pod ( Figure 6 ); pod 2 is a pod featuring an extended inflow path upstream of the wick ( Figure 7 ); and pod 3 is pod with the wick located in a stagnant vaporisation chamber and the inlet air bypassing the vaporisation chamber but entraining the vapour from an outlet of the vaporisation chamber ( Figures 8A and 8B ).
  • Pod 1 shown in longitudinal cross sectional view (in the width plane) in Figure 6 , has a main housing that defines a tank 160x holding an e-liquid aerosol precursor. Mouthpiece 154x is formed at the upper part of the pod. Electrical contacts 156x are formed at the lower end of the pod. Wick 162x is held in a vaporisation chamber. The air flow direction is shown using arrows.
  • Pod 2 shown in longitudinal cross sectional view (in the width plane) in Figure 7 , has a main housing that defines a tank 160y holding an e-liquid aerosol precursor. Mouthpiece 154y is formed at the upper part of the pod. Electrical contacts 156y are formed at the lower end of the pod. Wick 162y is held in a vaporisation chamber. The air flow direction is shown using arrows. Pod 2 has an extended inflow path (plenum chamber 157y) with a flow conditioning element 159y, configured to promote reduced turbulence at the wick 162y.
  • Figure 8A shows a schematic longitudinal cross sectional view of pod 3.
  • Figure 8B shows a schematic longitudinal cross sectional view of the same pod 3 in a direction orthogonal to the view taken in Figure 8A .
  • Pod 3 has a main housing that defines a tank 160z holding an e-liquid aerosol precursor. Mouthpiece 154z is formed at the upper part of the pod. Electrical contacts 156z are formed at the lower end of the pod. Wick 162z is held in a vaporisation chamber. The air flow direction is shown using arrows.
  • Pod 3 uses a stagnant vaporiser chamber, with the air inlets bypassing the wick and picking up the vapour/aerosol downstream of the wick.
  • Air velocity in the vicinity of the wick is believed to play an important role in affecting particle size.
  • the air velocity was calculated by dividing the flow rate by the intersection area, which is referred to as "calculated velocity" in this work. This involves a very crude simplification that assumes velocity distribution to be homogeneous across the intersection area.
  • the CFD model uses a laminar single-phase flow setup.
  • the outlet was configured to a corresponding flowrate
  • the inlet was configured to be pressure-controlled
  • the wall conditions were set as "no slip”.
  • a 1 mm wide ring-shaped domain (wick vicinity) was created around the wick surface, and domain probes were implemented to assess the average and maximum magnitudes of velocity in this ring-shaped wick vicinity domain.
  • the CFD model outputs the average velocity and maximum velocity in the vicinity of the wick for each set of experiments carried out in section 2.1. The outcomes are reported in Table 2.
  • turbulence intensity values represent higher levels of turbulence.
  • turbulence intensity below 1% represents a low-turbulence case
  • turbulence intensity between 1% and 5% represents a medium-turbulence case
  • turbulence intensity above 5% represents a high-turbulence case.
  • Turbulence intensity was assessed within the volume up to 1 mm away from the wick surface (defined as the wick vicinity domain). For the four experiments explained in section 2.2, the turbulence intensities are 0.55%, 0.77%, 1.06% and 1.34%, respectively, as also shown in Figures 4A-4D .
  • the cooling rate modelling involves three coupling models in COMSOL Multiphysics: 1) laminar two-phase flow; 2) heat transfer in fluids, and 3) particle tracing.
  • the model is setup in three steps:
  • Laminar mixture flow physics was selected in this study.
  • the outlet was configured in the same way as in section 3.1.
  • this model includes two fluid phases released from two separate inlets: the first one is the vapour released from wick surface, at an initial velocity of 2.84 cm/s (calculated based on 5 mg total particulate mass over 3 seconds puff duration) with initial velocity direction normal to the wick surface; the second inlet is air influx from the base of tube, the rate of which is pressure-controlled.
  • the inflow and outflow settings in heat transfer physics was configured in the same way as in the two-phase flow model.
  • the air inflow was set to 25 °C
  • the vapour inflow was set to 209 °C (boiling temperature of the e-liquid formulation).
  • the heat transfer physics is configured to be two-way coupled with the laminar mixture flow physics.
  • the above model reaches steady state after approximately 0.2 second with a step size of 0.001 second.
  • the particle tracing physics has one-way coupling with the previous model, which means the fluid flow exerts dragging force on the particles, whereas the particles do not exert counterforce on the fluid flow. Therefore, the particles function as moving probes to output vapour temperature at each timestep.
  • the model outputs average vapour temperature at each time steps.
  • a MATLAB script was then created to find the time step when the vapour cools to a target temperature (50°C or 75°C), based on which the vapour cooling rates were obtained (Table 3).
  • Table 3 Average vapour cooling rate obtained from Multiphysics modelling Tube size Flow rate Cooling rate to 50°C Cooling rate to 75°C [mm] [Ipm] [°C/ms] [°C/ms] 1.3 lpm constant flow rate 4.5 1.3 11.4 44.7 6 1.3 5.48 14.9 7 1.3 3.46 7.88 8 1.3 2.24 5.15 10 1.3 1.31 2.85 12 1.3 0.841 1.81 20 1.3 0* 0.536 50 1.3 0 0 2.0 lpm constant flow rate 4.5 2.0 19.9 670 5 2.0 13.3 67 6 2.0 8.83 26.8 8 2.0 3.61 8.93 12 2.0 1.45 3.19 20 2.0 0.395 0.761 50 2.0 0 0 * Zero cooling rate when the average vapour temperature is still above target temperature after
  • Particle size measurement results for the rectangular tube testing are shown in Table 4.
  • Table 4 For every tube size and flow rate combination, five repetition runs were carried out in the Spraytec laser diffraction system. The Dv50 values from five repetition runs were averaged, and the standard deviations were calculated to indicate errors, as shown in Table 4.
  • the particle size (Dv50) experimental results are plotted against calculated air velocity in Figure 9 .
  • the graph shows a strong correlation between particle size and air velocity.
  • Figure 10 shows the results of three experiments with highly different setup arrangements: 1) 5mm tube measured at 1.4 Ipm flow rate with Reynolds number of 155; 2) 8mm tube measured at 2.8 Ipm flow rate with Reynolds number of 279; and 3) 20mm tube measured at 8.6 Ipm flow rate with Reynolds number of 566. It is relevant that these setup arrangements have one similarity: the air velocities are all calculated to be 1 m/s.
  • Figure 10 shows that, although these three sets of experiments have different tube sizes, flow rates and Reynolds numbers, they all delivered similar particle sizes, as the air velocity was kept constant. These three data points were also plotted out in Figure 9 (1 m/s data with star marks) and they tie in nicely into particle size-air velocity trendline.
  • the particle size measurement data were plotted against the average velocity ( Figure 11 ) and maximum velocity ( Figure 12 ) in the vicinity of the wick, as obtained from CFD modelling.
  • the data in these two graphs indicates that in order to obtain an aerosol with Dv50 larger than 1 ⁇ m, the average velocity should be less than or equal to 1.2 m/s in the vicinity of the wick and the maximum velocity should be less than or equal to 2.0 m/s in the vicinity of the wick.
  • the average velocity should be less than or equal to 0.6 m/s in the vicinity of the wick and the maximum velocity should be less than or equal to 1.2 m/s in the vicinity of the wick.
  • typical commercial EVP devices deliver aerosols with Dv50 around 0.5 ⁇ m, and there is no commercially available device that can deliver aerosol with Dv50 exceeding 1 ⁇ m. It is considered that typical commercial EVP devices have average velocity of 1.5-2.0 m/s in the vicinity of the wick.
  • turbulence intensity is a quantitative characteristic that indicates the level of turbulence.
  • four tubes of different turbulence intensities were used to general aerosols which were measured in the Spraytec laser diffraction system.
  • the particle size (Dv50) experimental results are plotted against turbulence intensity in Figure 13 .
  • the graph suggests a correlation between particle size and turbulence intensity, that lower turbulence intensity is beneficial for obtaining larger particle size. It is noted that when turbulence intensity is above 1% (medium-turbulence case), there are relatively large measurement fluctuations. In Figure 13 , the tube with a jetting panel 10mm below the wick has the largest error bar, because air jets become unpredictable near the wick after traveling through a long distance.
  • Figure 14 shows the high temperature testing results. Larger particle sizes were observed from all 3 pods when the temperature of inlet air increased from room temperature (23°C) to 50 °C. When the pods were heated as well, two of the three pods saw even larger particle size measurement results, while pod 2 was unable to be measured due to significant amount of leakage.
  • laminar flow allows slow and gradual mixing between cold air and hot vapour, which means the vapour can cool down in slower rate when the airflow is laminar, resulting in larger particle size.
  • vapour cooling rates for each tube size and flow rate combination were obtained via multiphysics simulation.
  • particle size measurement results were plotted against vapour cooling rate to 50°C and 75°C, respectively.
  • the apparatus in order to obtain an aerosol with Dv50 larger than 1 ⁇ m, the apparatus should be operable to require more than 16 ms for the vapour to cool to 50°C, or an equivalent (simplified to an assumed linear) cooling rate being slower than 10 °C/ms.
  • the apparatus in order to obtain an aerosol with Dv50 larger than 1 ⁇ m, the apparatus should be operable to require more than 4.5 ms for the vapour to cool to 75°C, or an equivalent (simplified to an assumed linear) cooling rate slower than 30 °C/ms.
  • the apparatus should be operable to require more than 32 ms for the vapour to cool to 50°C, or an equivalent (simplified to an assumed linear) cooling rate being slower than 5 °C/ms.
  • the apparatus in order to obtain an aerosol with Dv50 of 2 ⁇ m or larger, should be operable to require more than 13 ms for the vapour to cool to 75°C, or an equivalent (simplified to an assumed linear) cooling rate slower than 10 °C/ms.
  • particle size (Dv50) of aerosols generated in a set of rectangular tubes was studied in order to decouple different factors (flow rate, air velocity, Reynolds number, tube size) affecting aerosol particle size. It is considered that air velocity is an important factor affecting particle size - slower air velocity leads to larger particle size. When air velocity was kept constant, the other factors (flow rate, Reynolds number, tube size) has low influence on particle size.

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EP19198589.4A 2019-09-20 2019-09-20 Rauchersatzvorrichtung Ceased EP3794973A1 (de)

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Application Number Priority Date Filing Date Title
EP19198589.4A EP3794973A1 (de) 2019-09-20 2019-09-20 Rauchersatzvorrichtung
EP20789848.7A EP3930497A1 (de) 2019-09-20 2020-09-21 Rauchersatzvorrichtung
PCT/EP2020/076285 WO2021053221A1 (en) 2019-09-20 2020-09-21 Smoking substitute apparatus
US17/693,992 US20220192258A1 (en) 2019-09-20 2022-03-14 Smoking substitute apparatus

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EP19198589.4A EP3794973A1 (de) 2019-09-20 2019-09-20 Rauchersatzvorrichtung

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040099266A1 (en) * 2002-11-27 2004-05-27 Stephen Cross Inhalation device for producing a drug aerosol
WO2016040575A1 (en) * 2014-09-10 2016-03-17 Fontem Holdings 1 B.V. Methods and devices for modulating air flow in delivery devices
US20170325505A1 (en) * 2014-12-15 2017-11-16 Philip Morris Products S.A. Split airflow system for an electrically heated smoking system and method for guiding an airflow inside an electrically heated smoking system
WO2018191766A1 (de) * 2017-04-20 2018-10-25 Von Erl. Gmbh Mundstück für einen inhalator
US20180360116A1 (en) * 2017-05-24 2018-12-20 Hauni Maschinenbau Gmbh Evaporator unit for an inhaler and method for controlling an evaporator unit
US20190150520A1 (en) * 2016-06-13 2019-05-23 Nicoventures Holdings Limited Aerosol delivery device
US10412996B2 (en) * 2015-12-22 2019-09-17 Altria Client Services Llc Cartridge for pump-operated aerosol-generating system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040099266A1 (en) * 2002-11-27 2004-05-27 Stephen Cross Inhalation device for producing a drug aerosol
WO2016040575A1 (en) * 2014-09-10 2016-03-17 Fontem Holdings 1 B.V. Methods and devices for modulating air flow in delivery devices
US20170325505A1 (en) * 2014-12-15 2017-11-16 Philip Morris Products S.A. Split airflow system for an electrically heated smoking system and method for guiding an airflow inside an electrically heated smoking system
US10412996B2 (en) * 2015-12-22 2019-09-17 Altria Client Services Llc Cartridge for pump-operated aerosol-generating system
US20190150520A1 (en) * 2016-06-13 2019-05-23 Nicoventures Holdings Limited Aerosol delivery device
WO2018191766A1 (de) * 2017-04-20 2018-10-25 Von Erl. Gmbh Mundstück für einen inhalator
US20180360116A1 (en) * 2017-05-24 2018-12-20 Hauni Maschinenbau Gmbh Evaporator unit for an inhaler and method for controlling an evaporator unit

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