NZ624118B2 - Detection of aerosol-forming substrate in an aerosol generating device - Google Patents
Detection of aerosol-forming substrate in an aerosol generating device Download PDFInfo
- Publication number
- NZ624118B2 NZ624118B2 NZ624118A NZ62411812A NZ624118B2 NZ 624118 B2 NZ624118 B2 NZ 624118B2 NZ 624118 A NZ624118 A NZ 624118A NZ 62411812 A NZ62411812 A NZ 62411812A NZ 624118 B2 NZ624118 B2 NZ 624118B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- heater element
- aerosol
- forming substrate
- energy
- power
- Prior art date
Links
- 239000000758 substrate Substances 0.000 title claims abstract description 147
- 239000000443 aerosol Substances 0.000 title claims abstract description 57
- 238000001514 detection method Methods 0.000 title description 9
- 239000000463 material Substances 0.000 claims abstract description 45
- 230000000391 smoking Effects 0.000 claims description 30
- 230000001276 controlling effect Effects 0.000 claims description 6
- 238000004590 computer program Methods 0.000 claims 1
- 241000208125 Nicotiana Species 0.000 description 46
- 235000002637 Nicotiana tabacum Nutrition 0.000 description 46
- 239000000969 carrier Substances 0.000 description 15
- 238000010438 heat treatment Methods 0.000 description 14
- 239000007787 solid Substances 0.000 description 14
- 150000001875 compounds Chemical class 0.000 description 13
- 238000000034 method Methods 0.000 description 13
- 239000007788 liquid Substances 0.000 description 11
- 238000005259 measurement Methods 0.000 description 11
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- -1 Nickel cadmium Chemical compound 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 235000019504 cigarettes Nutrition 0.000 description 6
- 238000002485 combustion reaction Methods 0.000 description 6
- 239000002775 capsule Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 5
- 239000000796 flavoring agent Substances 0.000 description 5
- REDXJYDRNCIFBQ-UHFFFAOYSA-N aluminium(3+) Chemical class [Al+3] REDXJYDRNCIFBQ-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 235000019634 flavors Nutrition 0.000 description 4
- 229910010293 ceramic material Inorganic materials 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 230000001419 dependent Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000011810 insulating material Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000000779 smoke Substances 0.000 description 3
- 240000006245 Dichrostachys cinerea Species 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium Ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 210000004072 Lung Anatomy 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 235000019568 aromas Nutrition 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 230000001186 cumulative Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 238000005338 heat storage Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- UFWIBTONFRDIAS-UHFFFAOYSA-N naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- DNIAPMSPPWPWGF-UHFFFAOYSA-N propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 2
- 230000000717 retained Effects 0.000 description 2
- 230000002441 reversible Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 230000014860 sensory perception of taste Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000011232 storage material Substances 0.000 description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 2
- 235000019640 taste Nutrition 0.000 description 2
- 230000035917 taste Effects 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N AI2O3 Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229920002301 Cellulose acetate Polymers 0.000 description 1
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 210000000887 Face Anatomy 0.000 description 1
- VBJZVLUMGGDVMO-UHFFFAOYSA-N Hafnium Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K Lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 210000000614 Ribs Anatomy 0.000 description 1
- 229920004933 Terylene® Polymers 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000001154 acute Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910052803 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 230000001809 detectable Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000000499 gel Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- PEDCQBHIVMGVHV-UHFFFAOYSA-N glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000003906 humectant Substances 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000011133 lead Substances 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910052987 metal hydride Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 230000000051 modifying Effects 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910021343 molybdenum disilicide Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 229910000601 superalloy Inorganic materials 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 239000002470 thermal conductor Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N tin hydride Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
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
- A24F40/20—Devices using solid 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
- A24F40/50—Control or monitoring
- A24F40/53—Monitoring, e.g. fault detection
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M11/00—Sprayers or atomisers specially adapted for therapeutic purposes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M11/00—Sprayers or atomisers specially adapted for therapeutic purposes
- A61M11/04—Sprayers or atomisers specially adapted for therapeutic purposes operated by the vapour pressure of the liquid to be sprayed or atomised
- A61M11/041—Sprayers or atomisers specially adapted for therapeutic purposes operated by the vapour pressure of the liquid to be sprayed or atomised using heaters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M11/00—Sprayers or atomisers specially adapted for therapeutic purposes
- A61M11/04—Sprayers or atomisers specially adapted for therapeutic purposes operated by the vapour pressure of the liquid to be sprayed or atomised
- A61M11/041—Sprayers or atomisers specially adapted for therapeutic purposes operated by the vapour pressure of the liquid to be sprayed or atomised using heaters
- A61M11/042—Sprayers or atomisers specially adapted for therapeutic purposes operated by the vapour pressure of the liquid to be sprayed or atomised using heaters electrical
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M15/00—Inhalators
- A61M15/06—Inhaling appliances shaped like cigars, cigarettes or pipes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0051—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes with alarm devices
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/021—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes operated by electrical means
- A61M16/022—Control means therefor
- A61M16/024—Control means therefor including calculation means, e.g. using a processor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/10—Preparation of respiratory gases or vapours
- A61M16/1075—Preparation of respiratory gases or vapours by influencing the temperature
- A61M16/109—Preparation of respiratory gases or vapours by influencing the temperature the humidifying liquid or the beneficial agent
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/16—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring distance of clearance between spaced objects
Abstract
There is provided an aerosol generating device comprising: a heater element (20) configured to heat an aerosol-forming substrate (2); a power source (40) connected to the heater element; and a controller (30) connected to the heater element and to the power source, wherein the controller is configured to control the power supplied to the heater element from the power source to maintain the temperature of the heater element at a target temperature, and is configured to compare a measure of power supplied to the heater element or energy supplied to the heater element from the power source to a threshold measure of power or energy to detect the presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element. ed to control the power supplied to the heater element from the power source to maintain the temperature of the heater element at a target temperature, and is configured to compare a measure of power supplied to the heater element or energy supplied to the heater element from the power source to a threshold measure of power or energy to detect the presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element.
Description
DETECTION OF AEROSOL-FORMING SUBSTRATE IN AN AEROSOL GENERATING
DEVICE
This specification relates to aerosol generating devices and in particular to aerosol
generating devices for user inhalation, such as smoking devices. The specification relates
to a device and method for detecting the presence or properties of an aerosol-forming
substrate in an aerosol generating device in a cost effective and reliable way.
Conventional lit end cigarettes deliver smoke as a result of combustion of the tobacco and
a wrapper which occurs at temperatures which may exceed 800 degrees Celsius during a
puff. At these temperatures, the tobacco is thermally degraded by pyrolysis and
combustion. The heat of combustion releases and generates various gaseous combustion
products and distillates from the tobacco. The products are drawn through the cigarette and
cool and condense to form a smoke containing the tastes and aromas associated with
smoking. At combustion temperatures, not only tastes and aromas are generated but also
a number of undesirable compounds.
Electrically heated smoking devices are known, which are essentially aerosol generating
systems, which operate at lower temperatures than conventional lit end cigarettes. An
example of such an electrical smoking device is disclosed in WO2009/118085.
WO2009/118085 discloses an electrical smoking system in which an aerosol-forming
substrate is heated by a heater element to generate an aerosol. The temperature of the
heater element is controlled to be within a particular range of temperatures in order to
ensure that undesirable volatile compounds are not generated and released from the
substrate while other, desired volatile compounds are released.
It is desirable to provide a substrate detection function in an aerosol generating device, for
example an aerosol generating device, in an inexpensive and reliable manner. Substrate
detection is useful, for example, for preventing activation of a heater element when a
substrate is not present and for preventing heating of unsuitable substrates.
In one embodiment there is provided an aerosol generating device comprising:
a heater element configured to heat an aerosol-forming substrate;
a power source connected to the heater element; and
a controller connected to the heater element and to the power source, wherein the
controller is configured to control the power supplied to the heater element from the power
source to maintain the temperature of the heater element at a target temperature, and is
configured to compare a measure of power supplied to the heater element or energy
supplied to the heater element from the power source to a threshold measure of power or
energy to detect the presence of an aerosol-forming substrate close to the heater element
or a material property of an aerosol-forming substrate close to the heater element.
As used herein, an ‘aerosol-generating device’ relates to a device that interacts with an
aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be
part of an aerosol-generating article, for example part of a smoking article. An aerosol-
generating device may be a smoking device that interacts with an aerosol-forming
substrate of an aerosol-generating article to generate an aerosol that is directly inhalable
into a user’s lungs thorough the user's mouth. An aerosol-generating device may be a
holder.
As used herein, the term ‘aerosol-forming substrate’ relates to a substrate capable of
releasing volatile compounds that can form an aerosol. Such volatile compounds may be
released by heating the aerosol-forming substrate. An aerosol-forming substrate may
conveniently be part of an aerosol-generating article or smoking article.
As used herein, the terms ‘aerosol-generating article’ and ‘smoking article’ refer to an
article comprising an aerosol-forming substrate that is capable of releasing volatile
compounds that can form an aerosol. For example, an aerosol-generating article may be a
smoking article that generates an aerosol that is directly inhalable into a user’s lungs
through the user's mouth. An aerosol-generating article may be disposable. The term
‘smoking article’ is generally used hereafter. A smoking article may be, or may comprise, a
tobacco stick.
The measure of power or energy can be any measure of power or energy, including
average power over a predetermined time period or over a predetermined number of
measurement cycles, a rate of change of power or energy or a cumulative measure of the
power or energy supplied over a predetermined time period or over a predetermined
number of measurement cycles.
In one embodiment, the measure of energy is normalised energy over a predetermined
time period. In another embodiment, the measure of energy is a rate of decrease of
normalised energy over a predetermined time period.
The amount of power or energy required to reach and maintain the heater element at a
target temperature depends on the rate of heat loss from the heater element. This is
strongly dependent on the environment surrounding the heater element. If a substrate is
close to or contacts the heater element it will affect the rate of heat loss from the heater
element compared to the situation in which there is no substrate close to the heater
element. In one embodiment, the device is configured to receive an aerosol- forming
substrate into contact with the heater element. The heater element then loses heat to the
substrate by conduction. The device may be configured so that the substrate surrounds the
heater element in use.
The controller may be configured to reduce to zero the supply of power to the heater
element from the power source if the measure of power or energy is less than the threshold
measure of power or energy. If the amount of energy needed to maintain the heater
element temperature at a target temperature is less than expected, it may be because an
aerosol forming substrate is not present in the device or it may be that an unsuitable
substrate, such as a previously used substrate, is in the device. A previously used
substrate will typically have lower water content and lower aerosol former content than a
new substrate and therefore draws less energy from the heater element. In either case it is
usually desirable to stop the supply of power to the heater.
The power source may be any suitable power supply, for example a DC voltage source,
such as a battery. In one embodiment, the power supply is a Lithium-ion battery.
Alternatively, the power supply may be a Nickel-metal hydride battery, a Nickel cadmium
battery, or a Lithium based battery, for example a Lithium-Cobalt, a Lithium-Iron-Phosphate
or a Lithium-Polymer battery. Power may be supplied to the heater element as a pulsed
signal. The amount of power delivered to the heater element may be adjusted by altering
the duty cycle or the pulse width of the power signal.
The controller may be configured to monitor the temperature of the heater element based
on a measure of the electrical resistance of the heater element. This allows the
temperature of the heater element to be detected without the need for additional sensing
hardware.
The temperature of the heater may be monitored at predetermined time periods, such as
every few milliseconds. This may be done continuously or only during periods when power
is being supplied to the heater element.
The device may include a data output means and the controller configured to provide a
record of the detected presence of an aerosol-forming substrate close to the heater
element or a material property of an aerosol-forming substrate close to the heater element
to the data output means. The substrate detection records may be useful to prevent
inappropriate data from being used during clinical analysis. For example the aerosol
generating device may include a wireless radio connected to the controller or a universal
serial bus (USB) socket connected to the controller. Alternatively, the aerosol generating
device may be configured to transfer data from the memory to an external memory in a
battery charging device every time the aerosol generating device is recharged through
suitable data connections. The device may be provided with special contacts for that
purpose.
The device may also include a non-volatile memory. The controller may be configured to
store substrate detection records in the memory. The memory may provide a temporary
data store for the records, before they are passed to a larger more permanent external
memory or directly to a data processing device.
In one embodiment, the controller is configured to provide a record of the detected
presence of an aerosol-forming substrate close to the heater element or a material property
of an aerosol-forming substrate close to the heater element to the data output means
during a charging operation of the power source. The device may be connected to a
charging device having a larger memory for longer term storage of the substrate detection
records.
The device may be an electrical smoking device. The aerosol-generating device may be an
electrically heated smoking device comprising an electric heater. The term “electric heater”
refers to one or more electric heater elements.
The electric heater may comprise a single heater element. Alternatively, the electric heater
may comprise more than one heater element. The heater element or heater elements may
be arranged appropriately so as to most effectively heat the aerosol-forming substrate.
The electric heater may comprise an electrically resistive material. Suitable electrically
resistive materials include but are not limited to: semiconductors such as doped ceramics,
electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon,
graphite, metals, metal alloys and composite materials made of a ceramic material and a
metallic material. Such composite materials may comprise doped or undoped ceramics.
Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable
metals include titanium, zirconium, tantalum and metals from the platinum group.
Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-,
aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-,
tin-, gallium-, manganese-, gold- and iron-containing alloys, and super-alloys based on
nickel, iron, cobalt, stainless steel, Timetal® and iron-manganese-aluminium based alloys.
In composite materials, the electrically resistive material may optionally be embedded in,
encapsulated or coated with an insulating material or vice-versa, depending on the kinetics
of energy transfer and the external physicochemical properties required. Alternatively, the
electric heater may comprise an infra-red heater element, a photonic source, or an
inductive heater element.
The electric heater may take any suitable form. For example, the electric heater may take
the form of a heating blade. Alternatively, the electric heater may take the form of a casing
or substrate having different electro-conductive portions, or an electrically resistive metallic
tube. Alternatively, one or more heating needles or rods that run through the centre of the
aerosol-forming substrate may be as already described. Alternatively, the electric heater
may be a disk (end) heater or a combination of a disk heater with heating needles or rods.
Other alternatives include a heating wire or filament, for example a Ni-Cr (Nickel-
Chromium), platinum, gold, silver, tungsten or alloy wire or a heating plate. Optionally, the
heater element may be deposited in or on a rigid carrier material. In one such embodiment,
the electrically resistive heater may be formed using a metal having a defined relationship
between temperature and resistivity. In such an exemplary device, the metal may be
formed as a track on a suitable insulating material, such as ceramic material, and then
sandwiched in another insulating material, such as a glass. Heaters formed in this manner
may be used to both heat and monitor the temperature of the heaters during operation.
The electric heater may comprise a heat sink, or heat reservoir comprising a material
capable of absorbing and storing heat and subsequently releasing the heat over time to the
aerosol-forming substrate. The heat sink may be formed of any suitable material, such as a
suitable metal or ceramic material. In one embodiment, the material has a high heat
capacity (sensible heat storage material), or is a material capable of absorbing and
subsequently releasing heat via a reversible process, such as a high temperature phase
change. Suitable sensible heat storage materials include silica gel, alumina, carbon, glass
mat, glass fibre, minerals, a metal or alloy such as aluminium, silver or lead, and a
cellulose material such as paper. Other suitable materials which release heat via a
reversible phase change include paraffin, sodium acetate, naphthalene, wax, polyethylene
oxide, a metal, metal salt, a mixture of eutectic salts or an alloy.
The heat sink or heat reservoir may be arranged such that it is directly in contact with the
aerosol-forming substrate and can transfer the stored heat directly to the substrate.
Alternatively, the heat stored in the heat sink or heat reservoir may be transferred to the
aerosol-forming substrate by means of a thermal conductor, such as a metallic tube.
The electric heater may heat the aerosol-forming substrate by means of conduction. In use,
the electric heater may be at least partially in contact with the substrate, or the carrier on
which the substrate is deposited. Alternatively, the heat from the electric heater may be
conducted to the substrate by means of a heat conductive element.
In one embodiment, power is supplied to the electric heater until the heater element or
elements of the electric heater reach a temperature of between approximately 250 °C and
440 °C. Any suitable temperature sensor and control circuitry may be used in order to
control heating of the heater element or elements to reach the temperature of between
approximately 250 °C and 440 °C, including the dual use heater discussed above. This is
in contrast to conventional cigarettes in which the combustion of tobacco and cigarette
wrapper may reach 800 °C.
The controller may comprise a programmable microprocessor. In another embodiment, the
controller may comprise a dedicated electronic chip such as a field programmable gate
array (FPGA) or an application specific integrated circuit (ASIC). In general, any device
capable of providing a signal capable of controlling a heater element may be used
consistent with the embodiments discussed herein. In one embodiment the controller is
configured to monitor a difference between the temperature of the heater element and the
target temperature to detect a change in air flow past the heater element indicative of a
user inhalation.
The aerosol forming substrate may be contained in a smoking article. During operation, the
smoking article containing the aerosol-forming substrate may be completely contained
within the aerosol-generating device. In that case, a user may puff on a mouthpiece of the
aerosol-generating device. A mouthpiece may be any portion of the aerosol-generating
device that is placed into a user’s mouth in order to directly inhale an aerosol generated by
the aerosol-generating article or aerosol-generating device. The aerosol is conveyed to the
user’s mouth through the mouthpiece. Alternatively, during operation the smoking article
containing the aerosol-forming substrate may be partially contained within the aerosol-
generating device. In that case, the user may puff directly on a mouthpiece of the smoking
article.
The smoking article may be substantially cylindrical in shape. The smoking article may be
substantially elongate. The smoking article may have a length and a circumference
substantially perpendicular to the length. The aerosol-forming substrate may be
substantially cylindrical in shape. The aerosol-forming substrate may be substantially
elongate. The aerosol-forming substrate may also have a length and a circumference
substantially perpendicular to the length. The aerosol-forming substrate may be received in
the sliding receptacle of the aerosol-generating device such that the length of the aerosol-
forming substrate is substantially parallel to the airflow direction in the aerosol-generating
device.
The smoking article may have a total length between approximately 30 mm and
approximately 100 mm. The smoking article may have an external diameter between
approximately 5 mm and approximately 12 mm. The smoking article may comprise a filter
plug. The filter plug may be located at the downstream end of the smoking article. The filter
plug may be a cellulose acetate filter plug. The filter plug is approximately 7 mm in length in
one embodiment, but may have a length of between approximately 5 mm to approximately
mm.
In one embodiment, the smoking article has a total length of approximately 45 mm. The
smoking article may have an external diameter of approximately 7.2 mm. Further, the
aerosol-forming substrate may have a length of approximately 10 mm. Alternatively, the
aerosol-forming substrate may have a length of approximately 12 mm. Further, the
diameter of the aerosol-forming substrate may be between approximately 5 mm and
approximately 12 mm. The smoking article may comprise an outer paper wrapper. Further,
the smoking article may comprise a separation between the aerosol-forming substrate and
the filter plug. The separation may be approximately 18 mm, but may be in the range of
approximately 5 mm to approximately 25 mm.
The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the
aerosol-forming substrate may comprise both solid and liquid components. The aerosol-
forming substrate may comprise a tobacco-containing material containing volatile tobacco
flavour compounds which are released from the substrate upon heating. Alternatively, the
aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming
substrate may further comprise an aerosol former that facilitates the formation of a dense
and stable aerosol. Examples of suitable aerosol formers are glycerine and propylene
glycol.
If the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-
forming substrate may comprise, for example, one or more of: powder, granules, pellets,
shreds, spaghettis, strips or sheets containing one or more of: herb leaf, tobacco leaf,
fragments of tobacco ribs, reconstituted tobacco, homogenised tobacco, extruded tobacco
and expanded tobacco. The solid aerosol-forming substrate may be in loose form, or may
be provided in a suitable container or cartridge. Optionally, the solid aerosol-forming
substrate may contain additional tobacco or non-tobacco volatile flavour compounds, to be
released upon heating of the substrate. The solid aerosol-forming substrate may also
contain capsules that, for example, include the additional tobacco or non-tobacco volatile
flavour compounds and such capsules may melt during heating of the solid aerosol-forming
substrate.
As used herein, homogenised tobacco refers to material formed by agglomerating
particulate tobacco. Homogenised tobacco may be in the form of a sheet. Homogenised
tobacco material may have an aerosol-former content of greater than 5% on a dry weight
basis. Homogenised tobacco material may alternatively have an aerosol former content of
between 5% and 30% by weight on a dry weight basis. Sheets of homogenised tobacco
material may be formed by agglomerating particulate tobacco obtained by grinding or
otherwise comminuting one or both of tobacco leaf lamina and tobacco leaf stems.
Alternatively, or in addition, sheets of homogenised tobacco material may comprise one or
more of tobacco dust, tobacco fines and other particulate tobacco by-products formed
during, for example, the treating, handling and shipping of tobacco. Sheets of homogenised
tobacco material may comprise one or more intrinsic binders, that is tobacco endogenous
binders, one or more extrinsic binders, that is tobacco exogenous binders, or a combination
thereof to help agglomerate the particulate tobacco; alternatively, or in addition, sheets of
homogenised tobacco material may comprise other additives including, but not limited to,
tobacco and non-tobacco fibres, aerosol-formers, humectants, plasticisers, flavourants,
fillers, aqueous and non-aqueous solvents and combinations thereof.
In a particularly preferred embodiment, the aerosol-forming substrate comprises a gathered
crimpled sheet of homogenised tobacco material. As used herein, the term ‘crimped sheet’
denotes a sheet having a plurality of substantially parallel ridges or corrugations.
Preferably, when the aerosol-generating article has been assembled, the substantially
parallel ridges or corrugations extend along or parallel to the longitudinal axis of the
aerosol-generating article. This advantageously facilitates gathering of the crimped sheet
of homogenised tobacco material to form the aerosol-forming substrate. However, it will be
appreciated that crimped sheets of homogenised tobacco material for inclusion in the
aerosol-generating article may alternatively or in addition have a plurality of substantially
parallel ridges or corrugations that are disposed at an acute or obtuse angle to the
longitudinal axis of the aerosol-generating article when the aerosol-generating article has
been assembled. In certain embodiments, the aerosol-forming substrate may comprise a
gathered sheet of homogenised tobacco material that is substantially evenly textured over
substantially its entire surface. For example, the aerosol-forming substrate may comprise a
gathered crimped sheet of homogenised tobacco material comprising a plurality of
substantially parallel ridges or corrugations that are substantially evenly spaced-apart
across the width of the sheet.
Optionally, the solid aerosol-forming substrate may be provided on or embedded in a
thermally stable carrier. The carrier may take the form of powder, granules, pellets, shreds,
spaghettis, strips or sheets. Alternatively, the carrier may be a tubular carrier having a thin
layer of the solid substrate deposited on its inner surface, or on its outer surface, or on both
its inner and outer surfaces. Such a tubular carrier may be formed of, for example, a
paper, or paper like material, a non-woven carbon fibre mat, a low mass open mesh
metallic screen, or a perforated metallic foil or any other thermally stable polymer matrix.
The solid aerosol-forming substrate may be deposited on the surface of the carrier in the
form of, for example, a sheet, foam, gel or slurry. The solid aerosol-forming substrate may
be deposited on the entire surface of the carrier, or alternatively, may be deposited in a
pattern in order to provide a non-uniform flavour delivery during use.
Although reference is made to solid aerosol-forming substrates above, it will be clear to one
of ordinary skill in the art that other forms of aerosol-forming substrate may be used with
other embodiments. For example, the aerosol-forming substrate may be a liquid aerosol-
forming substrate. If a liquid aerosol-forming substrate is provided, the aerosol-generating
device preferably comprises means for retaining the liquid. For example, the liquid aerosol-
forming substrate may be retained in a container. Alternatively or in addition, the liquid
aerosol-forming substrate may be absorbed into a porous carrier material. The porous
carrier material may be made from any suitable absorbent plug or body, for example, a
foamed metal or plastics material, polypropylene, terylene, nylon fibres or ceramic. The
liquid aerosol-forming substrate may be retained in the porous carrier material prior to use
of the aerosol-generating device or alternatively, the liquid aerosol-forming substrate
material may be released into the porous carrier material during, or immediately prior to
use. For example, the liquid aerosol-forming substrate may be provided in a capsule. The
shell of the capsule preferably melts upon heating and releases the liquid aerosol-forming
substrate into the porous carrier material. The capsule may optionally contain a solid in
combination with the liquid.
Alternatively, the carrier may be a non-woven fabric or fibre bundle into which tobacco
components have been incorporated. The non-woven fabric or fibre bundle may comprise,
for example, carbon fibres, natural cellulose fibres, or cellulose derivative fibres.
The aerosol-generating device may still further comprise an air inlet. The aerosol-
generating device may still further comprise an air outlet. The aerosol-generating device
may still further comprise a condensation chamber for allowing the aerosol having the
desired characteristics to form.
The aerosol-generating device is preferably a handheld aerosol-generating device that is
comfortable for a user to hold between the fingers of a single hand. The aerosol-generating
device may be substantially cylindrical in shape. The aerosol-generating device may have
a polygonal cross section and a protruding button formed on one face: in this embodiment,
the external diameter of the aerosol-generating device may be between about 12.7 mm
and about 13.65 mm measured from a flat face to an opposing flat face; between about
13.4 mm and about 14.2mm measured from an edge to an opposing edge (that is, from the
intersection of two faces on one side of the aerosol-generating device to a corresponding
intersection on the other side); and between about 14.2 mm and about 15 mm measured
from a top of the button to an opposing bottom flat face. The length of the aerosol
generating device may be between about 70mm and 120mm.
In another aspect embodiment, there is provided a method for detecting the presence of an
aerosol-forming substrate close to the heater element or a material property of an aerosol-
forming substrate in an aerosol generating device, the aerosol generating device
comprising a heater element configured to heat an aerosol-forming substrate and a power
source connected to the heater element, the method comprising:
controlling the power supplied to the heater element from the power source to maintain the
temperature of the heater element at a target temperature, comparing a measure of power
supplied to the heater element or energy supplied to the heater element from the power
source to a threshold measure of power or energy, and determining the presence of an
aerosol-forming substrate close to the heater element or a material property of an aerosol-
forming substrate close to the heater element based on a result of the step of comparing.
The measure of power or energy can be any measure of power or energy, including
average power over a predetermined time period or over a predetermined number of
measurement cycles, a rate of change of power or energy or a cumulative measure of the
power or energy supplied over a predetermined time period or over a predetermined
number of measurement cycles.
In one embodiment, the measure of energy is normalised energy over a predetermined
time period. In another embodiment, the measure of energy is a rate of decrease of
normalised energy over a predetermined time period.
The method may further comprise the step of reducing to zero the supply of power to the
heater element from the power source if the measure of power or energy is less than the
threshold measure of power or energy. If the amount of energy needed to reach and
maintain the heater element temperature at a target temperature is less than expected, it
may be because an aerosol forming substrate is not present in the device or it may be that
an unsuitable substrate, such as a previously used substrate, is in the device. In either
case it is usually desirable to stop the supply of power to the heater.
The method may include the step of monitoring the temperature of the heater element
based on a measure of the electrical resistance of the heater element.
In a further embodiment, there is provided a computer readable program that when
executed on a computer or other suitable processing device, carries out the method
described above. The specification includes embodiments that may be implemented as a
software product suitable for running on an aerosol generating devices having a
programmable controller as well as the other required hardware elements.
Examples will now be described in detail with reference to the accompanying drawings, in
which:
Figure 1 is a schematic drawing showing the basic elements of an aerosol generating
device in accordance with one embodiment;
Figure 2 is a schematic diagram illustrating the control elements of one embodiment;
Figure 3 is a graph illustrating the different the normalised energy required to be supplied to
a heater element to maintain the temperature at a target level for new, old and no substrate
next to the heater element; and
Figure 4 illustrates a control sequence for determining if an appropriate substrate is present
in the device.
In Figure 1, the inside of an embodiment of the electrically heated aerosol generating
system 100 is shown in a simplified manner. Particularly, the elements of the electrically
heated aerosol generating system 100 are not drawn to scale. Elements that are not
relevant for the understanding of the system have been omitted to simplify Figure 1.
The electrically heated aerosol generating system 100 comprises a housing 10 and an
aerosol-forming substrate 2, for example a cigarette. The aerosol-forming substrate 2 is
pushed inside the housing 10 to come into thermal proximity with the heater element 20.
The aerosol-forming substrate 2 will release a range of volatile compounds at different
temperatures. Some of the volatile compounds released from the aerosol-forming substrate
2 are only formed through the heating process. Each volatile compound will be released
above a characteristic release temperature. By controlling the maximum operation
temperature of the electrically heated aerosol generating system 100 to be below the
release temperature of some of the volatile compounds, the release or formation of these
smoke constituents can be avoided.
Additionally, the housing 10 comprises an electrical energy supply 40, for example a
rechargeable lithium ion battery. A controller 30 is connected to the heater element 20, the
electrical energy supply 40, a puff detector 32 and a graphical user interface 36, for
example a display.
The controller 30 controls the user interface 36 to display system information, for example,
battery power, temperature, status of aerosol-forming substrate 2, other messages or
combinations thereof.
The puff detector 32 is an optional element and detects airflow in the device, indicative of a
puff being taken by a user. The puff detector signals such a puff to the controller 30.
The controller 30 further controls the maximum operation temperature of the heater
element 20. The temperature of the heater element can be detected by a dedicated
temperature sensor. But in this embodiment the temperature of the heater element is
determined by monitoring its electrical resistivity. The electrical resistivity of a length of wire
is dependent on its temperature. Resistivity ρ increases with increasing temperature. The
actual resistivity ρ characteristic will vary depending on the exact composition of the alloy
and the geometrical configuration of the heater element 20, and an empirically determined
relationship can be used in the controller. Thus, knowledge of resistivity ρ at any given
time can be used to deduce the actual operation temperature of the heater element 20.
The resistance of the heater element R = V/I; where V is the voltage across the heater
element and I is the current passing through the heater element 20. The resistance R
depends on the configuration of the heater element 20 as well as the temperature and is
expressed by the following relationship:
R = ρ (T) ∗ L/S equation 1
Where ρ (T) is the temperature dependent resistivity, L is length and S the cross-sectional
area of the heater element 20. L and S are fixed for a given heater element 20
configuration and can be measured. Thus, for a given heater element design R is
proportional to ρ (T).
The resistivity ρ(T) of the heater element can be expressed in polynomial form as follows:
ρ (T) = ρ ∗ (1 + α T + α T ) equation 2
o 1 2
Where ρ is the resistivity at a reference temperature T and α and α are the polynominal
o o 1 2
coefficients.
Thus, knowing the length and cross-section of the heater element 20, it is possible to
determine the resistance R, and therefore the resistivity ρ at a given temperature by
measuring the heater element voltage V and current I. The temperature can be obtained
simply from a look-up table of the characteristic resistivity versus temperature relationship
for the heater element being used or by evaluating the polynomial of equation (2) above.
Preferably, the process may be simplified by representing the resistivity ρ versus
temperature curve in one or more, preferably two, linear approximations in the temperature
range applicable to tobacco. This simplifies evaluation of temperature which is desirable in
a controller 30 having limited computational resources.
Figure 2 is a block diagram illustrating the control elements of the device of Figure 1.
Figure 2 also shows the connection of the aerosol-generating device to an external device
58. The controller 30 includes a measurement unit 50 and a control unit 52. The
measurement unit is configured to determine the resistance R of the heater element 20.
The measurement unit 50 passes resistance measurements to the control unit 52. The
control unit 52 then controls the provision of power from the battery 40 to the heater
element 20 by toggling switch 54. The controller may comprise a microprocessor as well as
discrete electronic components.
In a preparation of the controlling of the temperature, a value for the target operation
temperature of the electrically heated aerosol generating system 100 is selected. The
selection is based on the release temperatures of the volatile compounds that should and
should not be released. This predetermined value is then stored in the control unit 52. The
control unit 52 includes a non-volatile memory 56.
The controller 30 controls the heating of the heater element 20 by controlling the supply
electrical energy from the battery to the heater element 20. By the switching of switch 54,
power is provided as a pulsed signal. The pulse width or duty cycle of the signal can be
modulated by the control unit 52 to alter the amount of energy supplied to the heater
element.
In use, the controller 30 measures the resistivity ρ of the heater element 20. The controller
then converts the resistivity of the heater element 20 into a value for the actual
operation temperature of the heater element, by comparing the measured resistivity ρ with
the look-up table. This may be done by the measurement unit 50 or by the control unit 52.
In the next step, the controller 30 compares the derived actual operation temperature with
the target operation temperature. If the actual operation temperature is below the target
operation temperature, the control unit 52 supplies the heater element 20 with additional
electrical energy in order to raise the actual operation temperature of the heater element
. If the actual operation temperature is above the target operation temperature, the
control unit 52 reduces the electrical energy supplied to the heater element 20 in order to
lower the actual operation temperature back to the target operation temperature.
The control unit may implement any suitable control technique to regulate the temperature,
such as a simple thermostatic feedback loop or a proportional, integral, derivative (PID)
control strategy.
The amount of energy required to reach the target temperature and maintain the heater
element at the target temperature depends on the presence or absence of a substrate
material 2 close to the heater element 20, and on the properties of the substrate. Figure 3
shows the evolution of normalised energy supplied to the heater element as a function of
time. Curve 60 is the normalised energy when a new substrate is in the device and curve
61 is the normalised energy when no substrate is in the device. The normalised energy is
the energy supplied during a fixed time interval normalised against an initial energy
measurement. A normalised measure of energy minimises the influence of environmental
conditions such as ambient temperature, airflow and humidity.
It can be seen that in both cases the power delivered to heater element monotonically
decreases with time following an initial high power period to bring the heater element up to
the target temperature. However, Figure 3 shows that at T= 10 seconds the amount of
energy supplied with a new substrate in the device is about twice the amount of energy
supplied when no substrate is present in the device. The difference in energy supplied
between a new and a previously heated substrate is smaller but still detectable. In one
embodiment, the difference in the normalized energy may be measured at T=5 seconds
and accurately determine if a substrate is present or not.
The controller is able to calculate the normalised energy supplied to the heater element up
to a predetermined time, and from that is able to determine if an expected or proper
substrate is in the device.
Figure 4 illustrates an example of a control process that can be carried out by the control
unit 52 to determine if a substrate is in the device or not. The process is a loop process and
starts at step 400. In step 410 the round number is incremented. At the start of the process
the round number is set to zero. Each time the control loop is passed through, the round
number is incremented in step 410. At step 420 the process branches depending on the
value of the round number. In the initial loop, when the round number equals one, the
process passes to step 430. At step 430 the initial energy, i.e. the energy supplied to the
heater so far, is set as the energy. This initial energy is used to normalise subsequent
energy measurements. The process then passes to step 440 and back to step 410.
Subsequent rounds pass directly from step 420 to step 440 until a decision round is
reached. Each round may be carried out at a fixed time interval, for example every two
seconds. The decision round corresponds to the time at which the controller is configured
to compare the normalised energy with an expected or threshold value to determine if a
substrate is present or not. The threshold value of normalised energy is illustrated by
dotted line 64 in Figure 3. In this example the decision round is round five, and occurs 10
seconds after the device is switched on. In the decision round, the process passes from
step 420 to step 450. In step 450 the normalised energy is calculated as the energy
supplied since the device was switched on divided by the product of the initial energy and
the decision round number (in this example five). The calculated normalised energy is then
compared to a threshold value in step 460. If the normalised energy exceeds the threshold
value then the control unit determines that an appropriate substrate is present and the
device can continue to be used. If the normalised energy does not exceed the threshold,
the control unit determines that no substrate (or an inappropriate substrate) is present and
the control unit then prevents the supply of power to the heater element by holding switch
54 open.
The process illustrated in Figure 4 is just one example of a process for determining if an
appropriate substrate is present in an aerosol generating device. Other measures of power
or energy supplied to the heater element may be used and normalised or non-normalised
data may be used. The time at which the determination is made is also a matter of choice.
The advantage of an early determination in order to take early action if necessary must be
balanced against the need to obtain a reliable result.
The measure of power or energy can be compared to a plurality of thresholds. This may be
useful to distinguish between different types of substrate or between an inappropriate
substrate and the absence of any substrate.
As well as being useful for dynamic control of the aerosol generating device, the substrate
detection data determined by the controller 30 may be useful for analysis purposes in
clinical trials. Figure 2 illustrates connection of the controller 30 to an external device 58.
The substrate detection data can be exported to the external device 58 (together with any
other captured data) and may be further relayed from the device 58 to other external
processing or data storage devices. The aerosol generating device may include any
suitable data output means. For example the aerosol generating device may include a
wireless radio connected to the controller 30 or memory 56, or a universal serial bus (USB)
socket connected to the controller 30 or memory 56. Alternatively, the aerosol generating
device may be configured to transfer data from the memory to an external memory in a
battery charging device every time the aerosol generating device is recharged through
suitable data connections. The battery charging device can provide a larger memory for
longer term storage of the puff data and can be subsequently connected to a suitable data
processing device or to a communications network.
The exemplary embodiments described above illustrate but are not limiting. In view of the
above discussed exemplary embodiments, other embodiments consistent with the above
exemplary embodiments will now be apparent to one of ordinary skill in the art.
The term ‘comprising’ as used in this specification and claims means ‘consisting at least in
part of’. When interpreting statements in this specification and claims which include the
term ‘comprising’, other features besides the features prefaced by this term in each
statement can also be present. Related terms such as ‘comprise’ and ‘comprised’ are to
be interpreted in a similar manner.
Claims (14)
1. An aerosol generating device comprising: a heater element configured to heat an aerosol-forming substrate; a power source connected to the heater element; and a controller connected to the heater element and to the power source, wherein the controller is configured to control the power supplied to the heater element from the power source to maintain the temperature of the heater element at a target temperature, and is configured to compare a measure of power supplied to the heater element or energy supplied to the heater element from the power source to a threshold measure of power or energy to detect the presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element.
2. An aerosol generating device according to claim 1, wherein the measure of energy is normalised energy or a rate of decrease of normalised energy over a predetermined time period.
3. An aerosol generating device according to claim 1 or 2, wherein the controller is configured to reduce to zero the supply of power to the heater element from the power source if the measure of power or energy is less than the threshold measure of power or energy.
4. An aerosol generating device according to any preceding claim, wherein the device is configured to receive an aerosol- forming substrate into contact with the heater element.
5. An aerosol generating device according to any preceding claim, wherein the controller is configured to monitor the temperature of the heater element based on a measure of the electrical resistance of the heater element.
6. An aerosol generating device according to any preceding claim, wherein the device is an electrical smoking device.
7. An aerosol generating device according to any preceding claim, wherein the device includes a data output means and wherein the controller is configured to provide a record of the detected presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element to the data output means.
8. An aerosol generating device according to claim 7, wherein the controller is configured to provide a record of the detected presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element to the data output means during a charging operation of the power source.
9. A method for detecting the presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate in an aerosol generating device, the aerosol generating device comprising a heater element configured to heat an aerosol-forming substrate and a power source connected to the heater element, the method comprising: controlling the power supplied to the heater element from the power source to maintain the temperature of the heater element at a target temperature, comparing a measure of power supplied to the heater element or energy supplied to the heater element from the power source to a threshold measure of power or energy, and determining the presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element based on a result of the step of comparing.
10. A method according to claim 9, further comprising the step of reducing to zero the supply of power to the heater element from the power source if the measure of power or energy is less than the threshold measure of power or energy.
11. A method according to claim 9 or 10, wherein the measure of energy is normalised energy or a rate of decrease of normalised energy over a predetermined time period.
12. A method according to claim 9, 10 or 11, further comprising the step of monitoring the temperature of the heater element based on a measure of the electrical resistance of the heater element.
13. A computer program that when executed on a computer or other suitable processing device, carries out the method of any one of claims 9 to 12.
14. An aerosol generating device according to claim 1, substantially as herein described with reference to any embodiment disclosed.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP11196227.0A EP2609820A1 (en) | 2011-12-30 | 2011-12-30 | Detection of aerosol-forming substrate in an aerosol generating device |
EP11196227.0 | 2011-12-30 | ||
PCT/EP2012/077063 WO2013098396A2 (en) | 2011-12-30 | 2012-12-28 | Detection of aerosol-forming substrate in an aerosol generating device |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ624118A NZ624118A (en) | 2016-02-26 |
NZ624118B2 true NZ624118B2 (en) | 2016-05-27 |
Family
ID=
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11395515B2 (en) | Aerosol generating device with air flow detection | |
CA2858476C (en) | Detection of aerosol-forming substrate in an aerosol generating device | |
TW201332462A (en) | Detection of aerosol-forming substrate in an aerosol generating device | |
NZ624118B2 (en) | Detection of aerosol-forming substrate in an aerosol generating device | |
NZ624115B2 (en) | Aerosol generating device with air flow detection |