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EP3858167A1 - Appareil de substitution du tabac - Google Patents

Appareil de substitution du tabac Download PDF

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Publication number
EP3858167A1
EP3858167A1 EP20154551.4A EP20154551A EP3858167A1 EP 3858167 A1 EP3858167 A1 EP 3858167A1 EP 20154551 A EP20154551 A EP 20154551A EP 3858167 A1 EP3858167 A1 EP 3858167A1
Authority
EP
European Patent Office
Prior art keywords
smoking substitute
aerosol
heatable
air
substitute apparatus
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.)
Withdrawn
Application number
EP20154551.4A
Other languages
German (de)
English (en)
Inventor
Benjamin ILLIDGE
Huanghai LU
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.)
IMPERIAL TOBACCO 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 EP20154551.4A priority Critical patent/EP3858167A1/fr
Publication of EP3858167A1 publication Critical patent/EP3858167A1/fr
Withdrawn legal-status Critical Current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
    • A24F40/46—Shape or structure of electric heating means
    • 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
    • A24F40/44—Wicks
    • 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
    • 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
    • A24F40/65—Devices with integrated communication means, e.g. wireless communication means

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.
  • the present disclosure is also devised in a manner that may also ameliorate a problem associated with the generation of heat in some smoking substitute systems.
  • a heating device heats an aerosol precursor
  • the enclosure or housing which surrounds the heater and aerosol precursor is also subjected to heating.
  • the enclosure can undergo thermal degradation, such as melting, softening, corrosion, spalling or combustion, which can result in deformation of the enclosure, and/or unwanted materials being entrained in the air flow for inhalation by a user.
  • This phenomenon is considered to be especially likely to occur when the enclosure is made of a plastics material. It is possible to mitigate this risk by designing relatively large and bulky smoking substitute systems in which the enclosure is disposed far away from the heater. Such systems are less convenient to store and hold by a user due to their size, and more costly to manufacture due to the large amount of material used to make them.
  • the present invention relates to a smoking substitute system providing an aerosol generator that has a heatable wicking portion and a shield portion shaped to at least partially enclose the heatable wicking portion in the vaporisation chamber, the heatable wicking portion and the shield portion being formed from ceramics materials.
  • a smoking substitute apparatus comprising an air passage through the device from an air inlet to an outlet and a vaporisation chamber in fluid communication with the air passage, the vaporisation chamber including an aerosol generator, operable to generate an aerosol for entrainment in an air flow along the air passage by vaporising a liquid aerosol precursor, wherein the aerosol generator includes a heatable wicking portion for vaporising the liquid aerosol precursor and a shield portion, the heatable wicking portion being formed from a porous ceramic material and the shield portion being formed from a ceramic material, and wherein the shield portion is shaped to at least partially enclose the heatable wicking portion in the vaporisation chamber.
  • the heatable wicking portion In use of the apparatus of the first aspect, the heatable wicking portion generates heat energy. Some of this energy heats and vaporises the aerosol precursor, with the remainder of the heat energy being excess heat energy. Some of the excess heat energy, in the absence of the present invention, would disadvantageously heat other parts of the apparatus, notably parts of a housing of the apparatus closest to the heatable wicking portion. Since it is preferred that some or all of the housing is formed of plastics material (for cost-effectiveness and ease of manufacture, for example), there is a risk of thermal damage to the housing.
  • the shield portion can intercept and absorb a significant proportion of the excess heat directed towards the housing and reduces heating thereof. This reduces the risk of thermal degradation of such parts of the housing.
  • the typical cooling effect of the bypass airflow through the vaporisation chamber is not provided. Therefore the material of the housing is particularly at risk of thermal degradation in the absence of the features of the present invention. Additionally, the aerosol generator and the housing of the apparatus can be positioned closer together than in a corresponding case in which the shield portion is absent.
  • the closest distance between the housing and the heatable wick portion may be at most 2 mm. This allows the overall size of the apparatus to be kept low, for user convenience, but the incorporation of the features of the invention reduces the risk of thermal degradation of the housing. More preferably, the closest distance between said part of the housing and the heatable wick portion may be at most 1.5 mm, or at most 1 mm. Alternatively or additionally, the closest distance between the housing and the heatable wick portion may be at least 0.25 mm, or at least 0.5 mm. This reduces a risk of thermal degradation of the housing due to a close proximity to the heatable wick portion.
  • the shield portion may be formed of a material having a thermal degradation temperature at least 100°C higher than that of the plastics material forming the housing. This reduces a risk of the shield portion thermally degrading and allowing more heat energy to be absorbed by the enclosure. More preferably, the thermal degradation temperature may be at least 150°C higher than that of the plastics material. More preferably the thermal degradation temperature may be at least 200°C higher than that of the plastics material.
  • the shield portion may present to the heatable wick portion a heat-absorbing surface having an area of at least twice as large as a plan view projection of the heatable wick portion onto the shield portion. This ensures that heat radiating from the heatable wick portion does not easily bypass the shield portion and excessively heat the housing.
  • the area of the heat-absorbing surface of the shield portion may be at least 20 mm 2 , or more preferably at least 30 mm 2 , or more preferably at least 40 mm 2 .
  • the vaporisation chamber may have an elongate shape, wider in a first direction orthogonal to a longitudinal axis of the apparatus compared with a second direction orthogonal to the first direction and to the longitudinal axis of the apparatus, the heatable wick portion extending along the first direction and the shield portion extending between the heatable wick portion and the housing substantially parallel to the first direction.
  • the wider first direction allows a sufficiently large heatable wick portion to be provided for the vaporisation of the aerosol precursor, while the narrower second direction ensures the apparatus is not too bulky for a user to hold.
  • the porosity of the heatable wicking portion may be at least 20 vol%.
  • the porosity of the heatable wicking portion may be at least 25 vol%, at least 30 vol%, or at least 35 vol%.
  • the lower limit of the porosity of the heatable wicking portion is set in order to provide suitable capacity in the heatable wicking portion to hold and wick the aerosol precursor.
  • the porosity of the shield portion may be at most 40 vol%.
  • the shield portion presents different requirements to the heatable wicking portion.
  • the shield portion is required to have structural integrity and to provide heat shielding for parts of the apparatus. Therefore it is possible for the shield portion in some embodiments to have substantially zero porosity. However, it is still of interest for the shield portion to have some porosity for the purpose of absorbing spitting of aerosol precursor emitted from the heatable wicking portion, which can happen in some circumstances. Accordingly, the porosity of the shield portion can be at least 10 vol%, or at least 15 vol% or at least 20 vol%.
  • the smoking substitute apparatus may further comprise a connection portion formed of ceramic material.
  • the connection portion may connect the heatable wicking portion and the shield portion.
  • the connection portion may position the heatable wicking portion in a spaced relation with respect to the shield portion.
  • the connection portion, shield portion and heatable wicking portion may be formed integrally. This permits a single component to be manufactured and installed in the apparatus. This can significantly simplify the design and manufacture of the apparatus, permitting tighter tolerances in the manufacture of the device and hence an overall smaller apparatus.
  • connection portion, shield portion and heatable wicking portion may be formed integrally and to have different porosity characteristics to each other.
  • the porosity may be graded between the different regions of the part. Suitable techniques to manufacture ceramic-based articles to achieve this include those disclosed in " Graded/Gradient Porous Biomaterials" by Xigeng Miao and Dan Sun, Materials (Basel). 2010 Jan; 3(1): 26-47 [https://doi.org/10.3390/ma3010026 ].
  • connection, shield and wicking portions can also be manufactured separately, then assembled together.
  • the wicking portion and the connection portion can be manufactured integrally and assembled with the shield portion.
  • the shield portion and the connection portion can be manufactured integrally and then assembled with the wicking portion.
  • connection portion may have a porosity that is lower than the porosity of the heatable wicking portion. This is because it is preferred that the connection portion does not significantly conduct liquid aerosol precursor. Furthermore, it is preferred that the connection portion be as thin as possible whilst still supporting the heatable wicking portion with respect to the shield portion. This reduces the heat to be conducted along the connection portion from the heatable wicking portion.
  • the porosity of the connection portion may be at most 10 vol%.
  • the porosity of the connection portion may be at most 8 vol%, at most 6 vol%, at most 4 vol%, at most 2 vol%, or the porosity of the connection portion may be substantially zero.
  • the smoking substitute apparatus may further comprise a reservoir for holding the liquid aerosol precursor.
  • a reservoir for holding the liquid aerosol precursor.
  • at least one part of the heatable wicking portion may be in fluid communication with the reservoir to allow liquid aerosol precursor from the reservoir to be conducted along the heatable wicking portion.
  • a resistive heater element (such as a metallic resistive heater element) may be incorporated in the heatable wicking portion.
  • the heater element may be embedded into the heatable wicking portion or is printed on the heatable wicking portion. This is advantageous compared with prior art approaches in which a coil heater is wound around a cotton wick, since the approach disclosed here allows a uniform construction for the heatable wicking portion and consequently a predictable and uniform heating operation in use.
  • the heatable wicking portion, and optionally the shield portion may be formed in monolithic form by sintering of ceramic particles.
  • a green body may be formed from ceramic particles (or precursor ceramic particles) by moulding from a slurry which is then set or allowed to dry (or both).
  • the green body optionally includes a binder and optionally includes a pore former.
  • the pore former may be concentrated in the part of the green body corresponding to the heatable wick portion.
  • the green body may then be subjected to calcination (to burn out the binder and any pore former) and then subjected to sintering (firing) heat treatment to cause at least partial sintering of the ceramic particles to provide a degree of strength to the finished component.
  • the ceramic material of the heatable wicking portion and/or of the shield portion is one or more of the materials selected from the group consisting of: alumina, zirconia and yttria-stabilized zirconia (YSZ).
  • alumina alumina
  • zirconia yttria-stabilized zirconia
  • YSZ yttria-stabilized zirconia
  • the heatable wicking portion may extend along a wick axis.
  • the shield portion may form a recessed shape spaced apart from the heatable wicking portion. In this way, when the smoking substitute device is held upright, the shield portion may be operable to catch and retain and optionally subsequently vaporise drips of liquid aerosol precursor from the heatable wick.
  • connection portion may connect to the shield portion at a mid point of the shield portion.
  • the connection portion may connect to the heatable wicking portion at a mid point of the heatable wicking portion.
  • At least a part of the air flow from the air inlet to the outlet may bypasses the vaporisation chamber. This is discussed in further detail below.
  • substantially all of the air flow from the air inlet to the outlet may bypass the vaporisation chamber, the vaporisation chamber having a vaporisation chamber outlet in communication with a passage along which air flows from the air inlet to the outlet.
  • the vaporisation chamber may be substantially sealed against air flow except for the vaporisation chamber outlet. This further ensures that the particles of the aerosol enter the air flow at substantially the same point in time, ensuring a more homogenous distribution of particle sizes in the air flow.
  • a first passage may lead from the air inlet to the outlet, the aerosol generator being arranged in fluid communication with the first passage, the apparatus may further comprise a second passage leading from the air inlet (or from a second air inlet) to the outlet, wherein the second passage bypasses the first passage downstream of the aerosol generator.
  • the smoking substitute apparatus may be comprised by or within a cartridge configured for engagement with a base unit, the cartridge and base unit together forming a smoking substitute system.
  • a smoking substitute system comprising: a base unit, and a smoking substitute apparatus according to the first preferred aspect wherein the smoking substitute apparatus is comprised by or within a cartridge configured for engagement with a base unit, the cartridge and base unit together forming a smoking substitute system, wherein the smoking substitute apparatus is removably engageable with the base unit.
  • a smoking substitute apparatus according to the first preferred aspect to generate an aerosol.
  • the smoking substitute apparatus may be in the form of a consumable.
  • the consumable may be configured for engagement with a main body.
  • 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. power supply, controller, sensor, 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 an 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 outlet may be at a mouthpiece of the smoking substitute apparatus.
  • a user may draw fluid (e.g. air) into and through the passage by inhaling at the outlet (i.e. using the mouthpiece).
  • the passage may be at least partially defined by the tank.
  • the tank may substantially (or fully) define the passage, for at least a part of the length of the passage.
  • the tank may surround the passage, e.g. in an annular arrangement around the passage.
  • the vaporisation chamber may be arranged to be in fluid communication with the inlet and outlet of the passage.
  • the vaporisation chamber may be an enlarged portion of the 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 passage.
  • the vaporisation chamber may be at least partially defined by the tank.
  • the tank may substantially (or fully) define the vaporisation chamber, and thus may form the enclosure. 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.
  • the part of the air flow which bypasses the vaporisation chamber may combine with the other part of the air flow (main air flow) for diluting the aerosol contained therein.
  • the dilution air flow may be directly inhaled by the user without passing through the passage of the smoking substitute apparatus.
  • the aerosol droplets as measured at the outlet of the passage, e.g. at the mouthpiece, may have a droplet size, dso, of less than 1 ⁇ m.
  • the dso particle size of the aerosol particles is preferably at least 1 ⁇ m, more preferably at least 2 ⁇ m.
  • the dso 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 particle droplet size, d 50 of an aerosol may be measured by a laser diffraction technique.
  • the stream of aerosol output from the outlet of the passage 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 (or main body engaged with the smoking substitute apparatus) may comprise a power source.
  • the power source 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 main body may comprise an identification means, which may, for example, be in the form of an RFID reader, a barcode or QR code reader.
  • This identification means may be able to identify a characteristic (e.g. a type) of a consumable engaged with the main body.
  • the consumable may include any one 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 identification means.
  • the smoking substitute apparatus or main body may comprise a controller, which may include a microprocessor.
  • the controller 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 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 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 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 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 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 .
  • Cooling of the vapour such that the time taken to cool to 50 °C is not less than 16 ms corresponds to an equivalent linear cooling rate of not more than 10 °C/ms.
  • 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 first 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.
  • the filament 164 and the exposed central portion of the porous wick 162 are positioned across the passage 170. More specifically, the part of passage that contains the filament 164 and the exposed portion of the porous wick 162 forms a vaporisation chamber.
  • the vaporisation chamber has the same cross-sectional diameter as the passage 170. However, in some embodiments the vaporisation chamber may have a different cross sectional profile compared with the passage 170. For example, the vaporisation chamber may have a larger cross sectional diameter than at least some of the downstream part of the passage 170 so as to enable a longer residence time for the air inside the vaporisation chamber.
  • 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 any one 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 shows a schematic heat shield configuration 200 of a smoking substitute apparatus according to a further reference arrangement.
  • Components and parts of the apparatus of this reference arrangement that are common to the first reference arrangement of Figure 19 are referenced with the same number, and are not discussed further in view of this reference arrangement.
  • the heat shield configuration 200 includes an enclosure 201 formed primarily of a plastic material, and two heat shield plates 202a, 202b.
  • the plates 202a, 202b are made of a material which has a thermal degradation temperature significantly higher than that of the plastic material which forms the enclosure 201.
  • thermal degradation temperature is used to describe the lowest temperature at which a material undergoes melting, softening, corrosion, spalling or combustion.
  • the plates 202a, 202b may therefore be made of a metal, ceramic, thermosetting polymer, or a composite thereof, and preferably have a thermal degradation temperature which is at least 100°C higher than that of the plastic enclosure material.
  • the plates 202a, 202b are configured to fit into and be held by grooves defined by the enclosure 201.
  • the heater 164 of this arrangement is disposed so as to be between the plates 202a, 202b when the plates are held by the grooves, but is not illustrated in Figure 21 .
  • the superior thermal degradation properties of the plates 202a, 202b allow them to protect the plastic enclosure 201 from excessive heating by the heater 164. Specifically, when heat energy radiates from the heater 164 towards the enclosure 201, a significant portion of the heat energy is intercepted and absorbed by the plates 202a, 202b, reducing the amount of heat energy available to heat the plastic material of the enclosure 201. This reduces the risk of the enclosure 201 reaching a temperature which would cause thermal degradation of the plastic material. Therefore, the enclosure 201 is less likely to deform due to heating and alter the intended air flow through the apparatus, and there is a reduced risk of harmful plastic matter becoming entrained in the air flow and into the lungs of the user, for example due to melting of the enclosure 201.
  • each plate 202a, 202b in the present reference arrangement presents to the heater 164 a heat-absorbing surface having an area of at least twice as large as a plan view projection of the heater onto the respective plate.
  • Figure 22 shows a plan view projection of a heater 164 and a wick 162 onto a heat-absorbing surface of plate 202a.
  • each heat shield plate 202a, 202b is also at least 20 mm 2 , but may be at least 30 mm 2 , or at least 40 mm 2 .
  • FIG. 23 A more detailed schematic of a cross section of a further heat shield configuration 300 of a smoking substitute apparatus according to another reference arrangement is illustrated in Figure 23 .
  • Components and parts of the apparatus of this reference arrangement that are common to the first reference arrangement of Figure 19 are referenced with the same number, and are not discussed further in view of this reference arrangement.
  • Figure 23 shows a cross sectional view of an enclosure 301 and heat shield plates 302a, 302b which are similar to those described in relation to Figure 21 . Also shown is a heater 164 of the apparatus wound around a wick 162, preferably in a helical manner. The plates 302a, 302b are disposed between the heater 164 and the enclosure 301 on opposing sides of the heater 164. This ensures the enclosure 301 is protected from both sides of the heater 164. Moreover, the enclosure 301 has a closest distance to the heater 164 of 2 mm, such that the size of the apparatus may be kept low while the heat shield plates 302a, 302b protects the enclosure 301 from thermal degradation.
  • Figure 24 illustrates a second perspective of the further heat shield configuration 300 of Figure 23 .
  • the enclosure 301 defines a vaporisation chamber, which has an elongate shape, wider in a first direction orthogonal to a longitudinal axis of the apparatus compared with a second direction orthogonal to the first direction and to the longitudinal axis of the apparatus.
  • the heater 164 extends along the first direction and the plates 302a, 302b extend between the heater 164 and the enclosure 301 substantially parallel to the first direction.
  • the wider first direction allows the heater 164 to be appropriately sized so as to sufficiently vaporise the aerosol precursor, while the narrower second direction provides a user-acceptable apparatus size and shape format and is possible due to the protecting characteristics of the plates 302a, 302b described previously.
  • a plastic housing 303 Also visible in Figure 24 is a plastic housing 303.
  • the plastic housing 303 allows the apparatus to be light-weight and cheap to manufacture, and provides the apparatus with a user-acceptable external format.
  • a single heat shield extending fully or partially around the heater.
  • Such a heat shield may have any one or a combination of the features described in relation to any of plates 202a, 202b, 302a, 302b.
  • An apparatus may be configured such that in use, at least part of the air flow drawn by a user through the apparatus from the air inlet to the outlet bypasses the vaporisation chamber defined by the enclosure.
  • a second reference arrangement of an apparatus shown in Figure 25 , provides an example of how such a bypassing air flow may be created. Accordingly, some embodiments of the invention may include one or a combination of the features of the second reference arrangement (and variations thereof) where such features are combinable with the present invention. This second reference arrangement is described below.
  • Figure 25 illustrates a schematic longitudinal cross sectional view of a second reference arrangement of the smoking substitute apparatus forming part of the smoking substitute system shown in Figures 17 and 18 .
  • the arrangement illustrated in Figure 25 differs from the first reference arrangement illustrated in Figure 19 in that the substitute smoking apparatus includes two bypass passages 180 in addition to the vaporiser passage 170.
  • the bypass air passages extend between the plurality of device air inlets 176 and two outlets 184.
  • the number of bypass passages 180 and corresponding outlets 184 may be greater or smaller than in the illustrated example.
  • the bypass passage 180 is shown with a substantially circular cross-sectional profile with a constant diameter along its length.
  • the bypass passage 180 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 bypass passage 180 may vary along its longitudinal axis.
  • a bypass passage 180 means that a part of the air drawn through the smoking substitute apparatus 150a when a user inhales via the mouthpiece 154 is not drawn through the vaporisation chamber. This has the effect of reducing the flow rate through the vaporisation chamber in correspondence with the respective flow resistances presented by the vaporiser passage 170 and the bypass passage 180. This can reduce the correlation between the flow rate through the smoking substitute apparatus 150a (i.e. the user's draw rate) and the particle size generated when the e-liquid 160 is vaporised and subsequently forms an aerosol. Therefore, the smoking substitute apparatus 150a of the second reference arrangement can deliver a more consistent aerosol to a user.
  • the smoking substitute apparatus 150a of the second reference arrangement is capable of producing an increased particle droplet size, dso, based on typical inhalation rates undertaken by a user, compared to the first reference arrangement of Figure 3 .
  • Such larger droplet sizes may be beneficial for the delivery of vapour to a user's lungs.
  • the preferred ratio between the dimensions of the bypass passage 180 and the dimensions of the vaporiser passage 170, and hence flow rate in the respective passages may be determined from representative user inhalation rates and from the required air flow rate through the vaporisation chamber to deliver a desired droplet size.
  • an average total flow rate of 1.3 litres per minute may be split such that 0.8 litres per minute passes through the bypass air channel 180, and 0.5 litres per minute passes through the vaporiser channel 170, a bypass:vaporiser flow rate ratio of 1.6:1.
  • a flow rate may provide an average droplet size, dso, of 1-3 ⁇ m (more preferably 2-3 ⁇ m) with a span of not more than 20 (preferably not more than 10).
  • Alternative flow rate ratios may be provided based on calculations and measurements of user flow rate, vaporiser flow rate, and average droplet size dso.
  • a bypass:vaporiser flow rate ratio of between 0.5:1 and 20:1, typically at an average total flow rate of 1.3 litres per minute may be advantageous depending on the configuration of the smoking substitute apparatus.
  • the bypass passage and vaporiser passage extend from a common device inlet 176. This has the benefit of ensuring more consistent airflow through the bypass passage 180 and vaporiser passage 170 across the lifetime of the smoking substitute apparatus 150a, since any obstruction that impinges on an air inlet 176 will affect the airflow through both passages equally. The impact of inlet manufacturing variations can also be reduced for the same reason. This can therefore improve the user experience for the smoking substitute apparatus 150a. Furthermore, the provision of a common device inlet 176 simplifies the construction and external appearance of the device.
  • bypass passage 180 and vaporiser passage 170 separate upstream of the vaporisation chamber. Therefore, no vapour is drawn through the bypass passage 180. Furthermore, because the bypass passage leads to outlet 184 that is separate from outlet 174 of the vaporiser passage, substantially no mixing of the bypass air and vaporiser air occurs within the smoking substitute apparatus 150a. Such mixing could otherwise lead to excessive cooling of the vapour and hence a build-up of condensation within the smoking substitute apparatus 150a. Such condensation could have adverse implications for delivering vapour to the user, for example by causing the user to draw liquid droplets rather than vapour when "puffing" on the mouthpiece 154.
  • the heat shield of the invention accommodates the reduced cooling present in the apparatus, lowering the risk of thermal degradation of the enclosure which may otherwise occur.
  • the apparatus may include one or a combination of features of a third reference arrangement (and variations thereof), shown schematically in Figure 26 , where such features are combinable with the present invention.
  • This third reference arrangement is described below.
  • Figure 26 illustrates a longitudinal cross sectional view of a consumable 250 according to a further arrangement.
  • the consumable 250 is shown attached, at a first end of the consumable 250, to the main body 120 of Figure 1 and Figure 2 . More specifically, the consumable 250 is configured to engage and disengage with the main body 120 and is interchangeable with the first reference arrangement 150 as shown in Figures 19 and 20 . Furthermore, the consumable 250 is configured to interact with the main body 120 in the same manner as the first reference arrangement 150 and the user may operate the consumable 250 in the same manner as the first reference arrangement 150.
  • the consumable 250 comprises a housing.
  • the consumable 250 comprises an aerosol generation chamber 280 in the housing.
  • the aerosol generation chamber 280 takes the form of an open ended container, or a cup, with a single chamber outlet 282 opened towards the outlet 274 of the consumable 250.
  • the housing has a plurality of air inlets 272 defined or opened at the sidewall of the housing.
  • An outlet 274 is defined or opened at a second end of the consumable 250 that comprises a mouthpiece 254.
  • a pair of passages 270 each extend between the respective air inlets 272 and the outlet 274 to provide flow passage for an air flow 412 as a user puffs on the mouthpiece 254.
  • the chamber outlet 282 is configured to be in fluid communication with the passages 270.
  • the passages 270 extend from the air inlets 272 towards the first end of the consumable 250 before routing back to towards the outlet 274 at the second end of the consumable 250. That is, a portion of each of the passages 270 axially extends alongside the aerosol generation chamber 280.
  • the passages 270 may extend from the air inlet 272 directly to the outlet 274 without routing towards the first end of consumable 250, e.g. the passages 270 may not axially extend alongside the aerosol generation chamber 280.
  • the housing may not be provided with any air inlet for an air flow to enter the housing.
  • the chamber outlet may be directly connected to the outlet of the housing by an aerosol passage and therefore said aerosol passage may only convey aerosol as generated in the aerosol generation chamber.
  • the discharge of aerosol may be driven at least in part by the pressure increase during vaporisation of aerosol form.
  • the chamber outlet 282 is positioned downstream from the heater in the direction of the vapour and/or aerosol flow 414 and serves as the only gas flow passage to the internal volume of the aerosol generation chamber 280.
  • the aerosol generation chamber 280 is sealed against air flow except for having the chamber outlet 282 in communication with the passages 270, the chamber outlet 282 permitting, in use, aerosol generated by the heater to be entrained into an air flow along the passage 270.
  • the sealed aerosol generation chamber 280 may comprise a plurality of chamber outlets 282 each arranged in fluid commutation with the passages 270.
  • the aerosol generation chamber 280 does not comprise any aperture upstream of the heater that may serve as an air flow inlet (although in some arrangements a vent may be provided).
  • the passages 270 of the consumable 250 allow the air flow, e.g. an entire amount of air flow, entering the housing to bypass the aerosol generation chamber 280.
  • the aerosol generation chamber may be considered to be a "stagnant" chamber.
  • the volumetric flowrate of vapour and/or aerosol in the aerosol generation chamber is configured to be less than 0.1 litre per minute.
  • the vaporised aerosol precursor may cool and therefore condense to form an aerosol in the aerosol generation chamber 280, which is subsequently expulsed into or entrained with the air flow in passages 270.
  • a portion of the vaporised aerosol precursor may remain as a vapour before leaving the aerosol generation chamber 280, and subsequently forms an aerosol as it is cooled by the air flow in the passages 270.
  • the flow path of the vapour and/or aerosol 414 is illustrated in Figure 26 .
  • the chamber outlet 282 is configured to be in fluid communication with a junction 290 at each of the passages 270 through a respective vapour channel 292.
  • the junctions 290 merge the vapour channels 292 with their respective passages 270 such that vapour and/or aerosol formed in the aerosol generation chamber 280 may expand or entrain into the passages 270 through junction inlets of said junctions 290.
  • the vapour channels form a buffering volume to minimise the amount of air flow that may back flow into the aerosol generation chamber 280.
  • the chamber outlet 282 may directly open towards the junction 290 at the passage, and therefore in such variations the vapour channel 292 may be omitted.
  • the chamber outlet may be closed by a one way valve.
  • Said one way valve may be configured to allow a one way flow passage for the vapour and/or aerosol to be discharged from the aerosol generation chamber, and to reduce or prevent the air flow in the passages from entering the aerosol generation chamber.
  • the aerosol generation chamber 280 is configured to have a length of 20mm and a volume of 680mm 3 .
  • the aerosol generation chamber is configured to allow vapour to be expulsed through the chamber outlet at a rate greater than 0.1mg/second.
  • the aerosol generation chamber may be configured to have an internal volume ranging between 68mm 3 to 680mm 3 , wherein the length of the aerosol generation chamber may range between 2mm to 20mm.
  • each of the passages 270 axially extends alongside the aerosol generation chamber 280.
  • the passages 270 are formed between the aerosol generation chamber 280 and the housing. Such an arrangement reduces heat transfer from the aerosol generation chamber 280 to the external surfaces of the housing.
  • the aerosol generation chamber 280 comprises a heater extending across its width.
  • the heater comprises a porous wick 262 and a heating filament 264 helically wound around a portion of the porous wick 162.
  • a tank 252 is provided in the space between the aerosol generation chamber 280 and the outlet 274, the tank being for storing a reservoir of aerosol precursor. Therefore in contrast with the reference arrangement as shown in Figures 19 and 20 , the tank 252 in the third reference arrangement does not substantially surround the aerosol generation chamber nor the passage 270. Instead, as shown in Figure 26 , the tank is substantially positioned above the aerosol generation chamber 280 and the porous wick 262 when the consumable 250 is placed in an upright orientation during use.
  • the end portions of the porous wick 262 each extend through the sidewalls of the aerosol generation chamber 280 and into a respective liquid conduit 266 which is in fluid communication with the tank 252.
  • the wick 262, saturated with aerosol precursor, may prevent gas flow passage into the liquid conduits 266 and the tank 252.
  • Such an arrangement may allow the aerosol precursor stored in the tank 252 to convey towards the porous wick 262 through the liquid conduits 266 by gravity.
  • the liquid conduits 266 are configured to have a hydraulic diameter that allow a controlled amount of aerosol precursor to flow from the tank 252 towards the porous wick 262. More specifically, the size of liquid conduits 266 are selected based on the rate of aerosol precursor consumption during vaporisation.
  • the liquid conduits 266 are sized to allow a sufficient amount of aerosol precursor to flow towards and replenish the wick, yet not so large as to cause excessive aerosol precursor to leak into the aerosol generation chamber.
  • the liquid conduits 266 are configured to have a hydraulic diameter ranging from 0.01mm to 10mm or 0.01mm to 5mm.
  • the liquid conduits 266 are configured to have a hydraulic diameter in the range of 0.1mm to 1mm.
  • the heating filament is electrically connected to electrical contacts 256 at the base of the aerosol generation chamber 280, sealed to prevent air ingress or fluid leakage. As shown in Figure 26 , when the first end of the consumable 250 is received into the main body 120, the electrical contacts 256 establish electrical communication with corresponding electrical contacts of the main body 120, and thereby allow the heater to be energised.
  • the vaporised aerosol precursor, or aerosol in the condensed form may discharge from the aerosol generation chamber 280 based on pressure difference between the aerosol generation chamber 280 and the passages 270.
  • pressure difference may arise form i) an increased pressure in the aerosol generation chamber 280 during vaporisation of aerosol form, and/or ii) a reduced pressure in the passage during a puff.
  • the heater when the heater is energised and forms a vapour, it expands in to the stagnant cavity of the aerosol generation chamber 280 and thereby causes an increase in internal pressure therein.
  • the vaporised aerosol precursor may immediately begin to cool and may form aerosol droplets.
  • Such increase in internal pressure causes convection inside the aerosol generation chamber which aids expulsing aerosol through the chamber outlet 282 and into the passages 270.
  • the heater is positioned within the stagnant cavity of the aerosol generation chamber 280, e.g. the heater is spaced from the chamber outlet 282.
  • Such arrangement may reduce or prevent the amount of air flow entering the aerosol generation chamber, and therefore it may minimise the amount of turbulence in the vicinity of the heater.
  • such arrangement may increase the residence time of vapour in the stagnant aerosol generation chamber 280, and thereby may result in the formation of larger aerosol droplets.
  • the heater may be positioned adjacent to the chamber outlet and therefore that the path of vapour 414 from the heater to the chamber outlet 282 is shortened. This may allow vapour to be drawn into or entrained with the air flow in a more efficient manner.
  • junction inlet at each of the junctions 290 opens in a direction orthogonal or non-parallel to the air flow. That is, the junction inlet each opens at a sidewall of the respective passages 270. This allows the vapour and/or aerosol from the aerosol generation chamber 280 to entrain into the air flow at an angle, and thus improving localised mixing of the different streams, as well as encouraging aerosol formation.
  • the aerosol may be fully formed in the air flow and be drawn out through the outlet at the mouthpiece.
  • the aerosol as generated by the illustrated third reference arrangement has a median droplet size d 50 of at least 1 ⁇ m. More preferably, the aerosol as generated by the illustrated third reference arrangement has a median droplet size d 50 of ranged between 2 ⁇ m to 3 ⁇ m.
  • Figures 27 and 28 respectively illustrate a schematic cross sectional view and a schematic perspective view of a heatable wicking portion, connecting portion and shield portion for use in embodiments of the invention.
  • these portions are formed as an integral component 600.
  • This integral component is intended to be positioned in the smoking substitute apparatus in the vaporisation chamber.
  • Heatable wicking portion 602 has a generally circular cylindrical form and extends along a principal axis so that its ends are in fluid communication with an e-liquid reservoir (not shown) of the apparatus.
  • the heatable wicking portion 602 has a similar volume to the wicks shown in the reference arrangements such as in Figs. 19 , 20 , 25 and 26 .
  • heatable wicking portion 602 does not have a separate metal heater coil wrapped around it. Instead, a metallic heater element is embedded into, or printed onto, the heatable wicking portion 602. This permits the heater to be formed at the time of manufacture of the heatable wicking portion, allowing for greater reproducibility of the heatable wicking portion.
  • the heatable wicking portion 602 is formed of porous ceramics material, the porosity permitting e-liquid to be conducted along the heatable wicking portion by capillary action.
  • the integral component 600 has a shield portion 604.
  • Shield portion is also formed from ceramics material, but preferably has lower porosity than the heatable wicking portion 602 and is more preferably substantially fully dense.
  • the shield portion 604, in this embodiment, has the form of a curved plate. As shown in the embodiment, the shield may have a curvature that is substantially centred on the principal axis of the heatable wicking portion 602. This configuration allows the shield portion 604 to be substantially equally spaced from the heatable wicking portion 602 over the extent of the shield portion.
  • the heatable wicking portion 602 is connected to the shield portion 604 by connecting portion 606.
  • Connecting portion 606 preferably takes the form of a relatively thin web of ceramics material.
  • the porosity of the connecting portion 606 may be similar to that of the shield portion 604.
  • the connecting portion 606 serves to retain the heatable wicking portion 602 in position relative to the shield portion 604.
  • the heatable wicking portion 602, the shield portion 604 and the connecting portion 606 may be manufactured in monolithic form by sintering of ceramic particles.
  • a green body is formed from ceramic particles (or precursor ceramic particles) by moulding from a slurry which is then set or allowed to dry (or both).
  • the green body may include a binder and includes a pore former at least at the part of the green body corresponding to the heatable wick portion.
  • the green body is then subjected to calcination (to burn out the binder and the pore former) and then subjected to sintering (firing) heat treatment to cause at least partial sintering of the ceramic particles to provide a degree of strength to the finished component.
  • the metallic heater element may be formed before or after the heat treatment.
  • the shield portion 604 serves to allow the formation of substantially stagnant zones 608 when air flows through the smoking substitute apparatus. This can lead to the advantageous effects reported in the present disclosure of control over the aerosol particle size characteristics.
  • the provision of stagnant characteristics in the vaporisation chamber can reduce or almost completely eliminate air flow over the heater. This significantly decreases the cooling effect that would otherwise be provided to the enclosure (or housing) by an air flow through the vaporisation chamber.
  • the shield portion is particularly beneficial in protecting the apparatus from high levels of excess heat energy which are not transported away by the air flow.
  • the air flow through the device is generally conventional, in that all of the air flow is intended to pass through the vaporisation chamber.
  • the heatable wick portion 602 is substantially sheltered from the air flow by the shield portion 604, although the air flow is available to pick up and transport away aerosol generated from the heatable wick portion.
  • 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 [mm] Flow rate [lpm] Cooling rate to 50°C [°C/ms] Cooling rate to 75°C [°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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Publication number Priority date Publication date Assignee Title
WO2023052091A1 (fr) * 2021-09-28 2023-04-06 Nerudia Limited Élément de distribution d'aérosol
JP2024544342A (ja) * 2021-12-24 2024-11-28 深▲セン▼市新宜康科技股▲分▼有限公司 熱交換器、段階分け加熱装置、及びエアロゾル発生装置

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