Note: Descriptions are shown in the official language in which they were submitted.
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NON-COMBUSTIBLE AEROSOL PROVISION SYSTEM
Field
The present disclosure relates to non-combustible aerosol provision systems
such as
electronic smoking articles and the like.
Background
Non-combustible aerosol provision systems (e.g. e-cigarettes / tobacco heating
products)
generally contain an aerosolisable material, such as a reservoir of a source
liquid containing
a formulation, typically including nicotine, or a solid material such as a
tobacco-based
product, from which an aerosol is generated for inhalation by a user, for
example through
heat vaporisation. Thus, an non-combustible aerosol provision system will
typically comprise
an aerosol generation chamber containing a vaporiser, e.g. a heater, arranged
to vaporise a
portion of aerosolisable material to generate an aerosol in the aerosol
generation chamber.
As a user inhales on the device and electrical power is supplied to the
heater, air is drawn
into the device and into the aerosol generation chamber where the air mixes
with the
vaporised aerosolisable material and forms a condensation aerosol. There is a
flow path
between the aerosol generation chamber and an opening in the mouthpiece so the
air drawn
through the aerosol generation chamber continues along the flow path to the
mouthpiece
opening, carrying some of the condensation aerosol with it, and out through
the mouthpiece
opening for inhalation by the user.
Once the initial amount of liquid is consumed, the user must replace the
aerosolisable
material. In the case of e-cigarettes, this is generally done by either re-
filling the device with
liquid only (possible in so-called "open" systems) or by replacing the entire
unit which
contained the liquid with a new liquid containing unit (so-called "closed"
systems).
In the case of non-combustible tobacco heating products, the aerosolisable
material is
generally incorporated within a solid material which is typically heated so as
to generate a
condensation aerosol. Similarly to e-cigarettes, such devices typically
contain a finite source
of aerosolisable material such that either the specific solid material which
is being heated
needs replaced/replenished (as may be the case in loose-leaf tobacco heating
products), or
an article containing the solid aerosolisable material is
replaced/replenished.
Approaches are described herein which seek to help provide new approaches to
monitoring
the consumption of the aerosolisable material.
Summary
In one aspect of the present disclosure there is provided a method of
operating an non-
combustible aerosol provision system comprising control circuitry, a power
source and an
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aerosol generator configured to generate an aerosol from an aerosolisable
material, wherein
the control circuitry performs the method of causing delivery of power from
the power source
to the aerosol generator for an aerosol generation event in response to a user
input, and
determining the amount of aerosol generated from the aerosolisable material,
in response to
the user input, based on a determined rate of aerosol generation, wherein the
determined
rate of aerosol generation is adjusted based on a dynamic factor.
In a further aspect of the present disclosure there is provided a control unit
for use with an
electronic non-combustible aerosol provision device comprising: a power
source; and control
circuitry configured to cause the delivery of power from the power source to
an aerosol
generator for an aerosol generation event in response to a user input, wherein
the aerosol
generator is configured to generate an aerosol from an aerosolisable material
during the
aerosol generation event; wherein the control circuitry is further configured
to determine the
amount of aerosol generated from the aerosolisable material, in response to
the user input,
based on a determined rate of aerosol generation, wherein the rate of aerosol
generation is
adjusted based on a dynamic factor.
In a further aspect of the present disclosure there is provided a non-
combustible aerosol
provision system comprising:
a control unit comprising: a power source; and control circuitry configured to
cause
the delivery of power from the power source to an aerosol generator for an
aerosol
generation event in response to a user input, wherein the aerosol generator is
configured to
generate an aerosol from an aerosolisable material during the aerosol
generation event;
wherein the control circuitry is further configured to determine the amount of
aerosol
generated from the aerosolisable material, in response to the user input,
based on a
determined rate of aerosol generation, wherein the rate of aerosol generation
is adjusted
based on a dynamic factor;
the aerosol generator; and
the aerosolisable material.
In a further aspect of the present disclosure there is provided a non-
combustible aerosol
provision means comprising: power source means; control means configured to
cause the
delivery of power from the power source means to an aerosol generator means
for a period
of time in response to a user input, wherein the aerosol generator means is
configured to
generate an aerosol from an aerosolisable material means; and wherein the
control means
is further configured to determine the amount of aerosol generated from the
aerosolisable
material means, in response to the user input, based on a determined rate of
aerosol
generation, wherein the rate of aerosol generation is adjusted based on a
dynamic factor.
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These and other aspects as apparent from the following description form part
of the present
disclosure. It is expressly noted that a description of one aspect may be
combined with one
or more other aspects, and the description is not to be viewed as being a set
of discrete
paragraphs which cannot be combined with one another.
Brief Description of the Drawings
Embodiments of the invention will now be described, by way of example only,
with reference
to the accompanying drawings, in which:
Figure 1 schematically represents in cross-section a non-combustible aerosol
provision
system in accordance with certain embodiments of the disclosure;
Figure 2 schematically represent certain operating steps for non-combustible
aerosol
provision systems in accordance with certain embodiments of the disclosure;
and
Figure 3 is a diagram representing the rate of mass loss for repeats of
different length heater
activations of an non-combustible aerosol provision system in accordance with
certain
embodiments of the disclosure.
Detailed Description
Aspects and features of certain examples and embodiments are discussed /
described
herein. Some aspects and features of certain examples and embodiments may be
implemented conventionally and these are not discussed / described in detail
in the interests
of brevity. It will thus be appreciated that aspects and features of apparatus
and methods
discussed herein which are not described in detail may be implemented in
accordance with
any conventional techniques for implementing such aspects and features.
According to the present disclosure, a "non-combustible" non-combustible
aerosol provision
system is one where a constituent aerosol-generating material of the non-
combustible
aerosol provision system (or component thereof) is not combusted or burned in
order to
facilitate delivery of at least one substance to a user.
In some embodiments, the delivery system is a non-combustible aerosol
provision system,
such as a powered non-combustible aerosol provision system.
In some embodiments, the non-combustible aerosol provision system is an
electronic
cigarette, which may also be known as a vaping device or electronic nicotine
delivery system
(END), although it is noted that the presence of nicotine in the aerosol-
generating material is
not a requirement.
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In some embodiments, the non-combustible aerosol provision system is an
aerosol-
generating heating system, also known as a heat-not-burn system. An example of
such a
system is a tobacco heating system.
In some embodiments, the non-combustible aerosol provision system is a hybrid
system to
generate aerosol using a combination of aerosol-generating materials, one or a
plurality of
which may be heated. Each of the aerosol-generating materials may be, for
example, in the
form of a solid, liquid or gel and may or may not contain nicotine. In some
embodiments, the
hybrid system comprises a liquid or gel aerosol-generating material and a
solid aerosol-
generating material. The solid aerosol-generating material may comprise, for
example,
tobacco or a non-tobacco product.
Typically, the non-combustible aerosol provision system may comprise a non-
combustible
aerosol provision device and a consumable for use with the non-combustible
aerosol
provision device.
In some embodiments, the non-combustible aerosol provision system, or the non-
combustible aerosol provision device thereof, may comprise a power source and
a
controller. The power source may, for example, be an electric power source or
an
exothermic power source. In some embodiments, the exothermic power source
comprises a
carbon substrate which may be energised so as to distribute power in the form
of heat to an
aerosol-generating material or to a heat transfer material in proximity to the
exothermic
power source.
Non-combustible aerosol provision systems often, though not always, comprise a
modular
assembly including both a reusable part (also referred to as a control unit)
and a replaceable
/ disposable cartridge part (also referred to as a consumable part). Often the
replaceable
cartridge part will comprise the aerosolisable material and the vaporiser and
the reusable
part will comprise the power supply (e.g. rechargeable battery), activation
mechanism (e.g.
button or puff sensor), and control circuitry. However, it will be appreciated
these different
parts may also comprise further elements depending on functionality. For
example, for a so-
called hybrid device the cartridge part may also comprise an additional
flavour element, e.g.
a portion of tobacco, provided as an insert (sometimes referred to as a "pod")
to add flavour
to an aerosol generated elsewhere in the system. In such cases the flavour
element insert
may itself be removable from the disposable cartridge part so it can be
replaced separately
from the cartridge, for example to change flavour or because the usable
lifetime of the
flavour element insert is less than the usable lifetime of the aerosol
generating components
of the cartridge. The reusable device part will often also comprise additional
components,
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such as a user interface for receiving user input and displaying operating
status
characteristics.
For modular devices a cartridge and control unit are electrically and
mechanically coupled
together for use, for example using a screw thread, magnetic, latching or
bayonet fixing with
appropriately engaging electrical contacts. When the aerosolisable material in
a cartridge is
exhausted, or the user wishes to switch to a different cartridge having a
different
aerosolisable material, a cartridge may be removed from the control unit and a
replacement
cartridge attached in its place. Devices conforming to this type of two-part
modular
configuration may generally be referred to as two-part devices or multi-part
devices.
It is relatively common for non-combustible aerosol provision systems,
including multi-part
devices, to have a generally elongate shape and, for the sake of providing a
concrete
example, certain embodiments of the disclosure described herein will be taken
to comprise a
generally elongate multi-part device employing disposable cartridges which
include an
aerosolisable material and electric heater for vaporising the aerosolisable
material to form a
condensation aerosol for user inhalation during use. However, it will be
appreciated the
underlying principles described herein may equally be adopted for different
configurations of
non-combustible aerosol provision systems, for example single-part devices or
modular
devices comprising more than two parts, refillable devices and single-use
disposable
devices, hybrid devices which have an additional flavour element, as well as
devices
conforming to other overall shapes, for example based on so-called box-mod
high
performance devices that typically have a more box-like shape or smaller form-
factor
devices such as so-called pod-mod devices. More generally, it will be
appreciated
embodiments of the disclosure may be based on non-combustible aerosol
provision systems
configured to incorporate the principles described herein regardless of the
specific format of
other aspects of such non-combustible aerosol provision systems.
Figure 1 is a cross-sectional view through an example non-combustible aerosol
provision
system 1 in accordance with certain embodiments of the disclosure. The non-
combustible
aerosol provision system 1 comprises two main components, namely a control
unit 2 (which
may, for example, also be referred to as a reusable part) and a consumable
part 4 (which
may, for example, also be referred to as a replaceable / disposable cartridge
part).
In normal use the control unit 2 and the consumable part 4 are releasably
coupled together
at an interface 6. When the consumable part is exhausted or the user simply
wishes to
switch to a different consumable part, the consumable part may be removed from
the control
unit and a replacement consumable part attached to the control unit in its
place. The
interface 6 provides a structural, electrical and air path connection between
the two parts
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and may be established in accordance with conventional techniques, for example
based
around a screw thread, latch mechanism, or bayonet fixing with appropriately
arranged
electrical contacts and openings for establishing the electrical connection
and air path
between the two parts as appropriate. The specific manner by which the
consumable part 4
mechanically mounts to the control unit 2 is not significant to the principles
described herein,
but for the sake of a concrete example is assumed here to comprise a latching
mechanism,
for example with a portion of the cartridge being received in a corresponding
receptacle in
the control unit with cooperating latch engaging elements (not represented in
Figure 1). It will
also be appreciated the interface 6 in some implementations may not support an
electrical
connection between the respective parts. For example, in some implementations
a vaporiser
may be provided in the control unit rather than in the consumable part.
The consumable part 4 comprises a consumable housing 42 formed of a plastics
material.
The consumable housing 42 supports other components of the consumable part and
provides the mechanical interface 6 with the control unit 2. The consumable
housing 42 in
this example is generally circularly symmetric about a longitudinal axis along
which the
consumable part couples to the control unit 2 and has a length of around 4 cm
and a
diameter of around 1.5 cm. However, it will be appreciated the specific
geometry, and more
generally the overall shapes and materials used, may be different in different
implementations.
Within the consumable housing 42 is a reservoir 44 that contains liquid
aerosolisable
material. The liquid aerosolisable material may be conventional, and may be
referred to as
e-liquid. The liquid reservoir 44 in this example has an annular shape with an
outer wall
defined by the consumable housing 42 and an inner wall that defines an air
path 52 through
the consumable part 4. The reservoir 44 is closed at each end with end walls
to contain the
e-liquid. The reservoir 44 may be formed in accordance with conventional
techniques, for
example it may comprise a plastics material and be integrally moulded with the
consumable
housing 42. The opening of the air path 52 at the end of the consumable part 4
provides a
mouthpiece outlet 50 for the non-combustible aerosol provision system through
which a user
inhales aerosol generated by the non-combustible aerosol provision system
during use.
The consumable part further comprises a wick 63 and a heater (vaporiser) 65
located
towards an end of the reservoir 44 opposite to the mouthpiece outlet 50. In
this example the
wick 63 extends transversely across the cartridge air path 52 with its ends
extending into the
reservoir 44 of e-liquid through openings in the inner wall of the reservoir
44. The openings
in the inner wall of the reservoir are sized to broadly match the dimensions
of the wick 63 to
provide a reasonable seal against leakage from the liquid reservoir into the
cartridge air path
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without unduly compressing the wick, which may be detrimental to its fluid
transfer
performance.
The wick 63 and heater 65 are arranged in the cartridge air path 52 such that
a region of the
cartridge air path 52 around the wick 63 and heater 65 in effect defines a
vaporisation region
for the consumable part. E-liquid in the reservoir 44 infiltrates the wick 63
through the ends
of the wick extending into the reservoir 44 and is drawn along the wick by
surface tension /
capillary action (i.e. wicking). The heater 65 in this example comprises an
electrically
resistive wire coiled around the wick 63 and is discussed further below. In
this example the
wick 63 comprises a glass fibre bundle, but it will be appreciated the
specific wick
configuration is not significant to the principles described herein. In use
electrical power may
be supplied to the heater 65 to vaporise an amount of e-liquid (aerosolisable
material) drawn
to the vicinity of the heater 65 by the wick 63. Vaporised e-liquid may then
become entrained
in air drawn along the cartridge air path from the vaporisation region to form
a condensation
aerosol that exits the system through the mouthpiece outlet 50 for user
inhalation. Thus
electrical power can be applied to the heater 65 to selectively generate
aerosol from the e-
liquid in the consumable part 4. When the device is in use and generating
aerosol, the
amount of power supplied to the heater 65 may be varied, for example through
pulse width
and / or frequency modulation techniques, to control the temperature and / or
rate of aerosol
generation as desired.
The general configuration of the wicking element and the heating element may
follow
conventional techniques. For example, in some implementations the wicking
element and
the heating element may comprise separate elements, e.g. a metal heating wire
wound
around / wrapped over a cylindrical wick, the wick, for instance, consisting
of a bundle,
thread or yarn of glass fibres. In other implementations, the functionality of
the wicking
element and the heating element may be provided by a single element. That is
to say, the
heating element itself may provide the wicking function. Thus, in various
example
implementations, the heating element / wicking element may comprise one or
more of: a
metal composite structure, such as porous sintered metal fibre media (Bekipor0
ST) from
Bekaert, a metal foam structure, e.g. of the kind available from Mitsubishi
Materials; a multi-
layer sintered metal wire mesh, or a folded single-layer metal wire mesh, such
as from Bopp;
a metal braid; or glass-fibre or carbon-fibre tissue entwined with metal
wires. The "metal"
may be any metallic material having an appropriate electric resistivity to be
used in
connection / combination with a battery. The "metal" could, for example, be a
NiCr alloy (e.g.
NiCr8020) or a FeCrAl alloy (e.g. "Kanthal") or stainless steel (e.g. AISI 304
or AISI 316).
It will be appreciated the specific geometry and overall resistance of a
heater in accordance
with embodiments of the disclosure may be chosen having regard to the
implementation at
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hand, for example having regard to the geometry of a wick 63 and air path 52
for an
implementation of the kind shown in Figure 1, and also the desired amount of
power to be
dissipated in the heater during use and the power supply voltage. For the
example the
heater 65 may comprise around 10 turns of wire loosely wound around the wick
63 with an
inner diameter of around 2.5 mm and that the thickness of the wire is
appropriately chosen
so the overall resistance of the electric heating is around 1.3 ohms. However,
it will be
appreciated different electric heater configuration having different
electrical resistance may
be used for other implementations, for example in other implementations the
electric heater
may have an electrical resistance within a range selected from the group
comprising: 0.5 to
2 ohms, 0.8 to 1.8 ohms, 0.9 to 1.7 ohms, 1.0 to 1.6 ohms, 1.1 to 1.5 ohms and
1.2t0 1.4
ohms. Values below 0.5 Ohm could be used provided an appropriate power source
is
selected.
Turning now to the control unit 2, this comprises an outer housing 12 with an
opening that
defines an air inlet 28 for the non-combustible aerosol provision system, a
battery 26 for
providing operating power for the non-combustible aerosol provision system,
control circuitry
for controlling and monitoring the operation of the non-combustible aerosol
provision
system, a user input button 14, an inhalation sensor (puff detector) 16, which
in this example
comprises a pressure sensor located in a pressure sensor chamber 18, and a
visual display
24. The control circuitry is configured to monitor the output from the
inhalation sensor to
20 determine when a user is inhaling through the mouthpiece opening 50 of
the non-
combustible aerosol provision system so that power can be automatically
supplied to the
vaporiser 65 to generate aerosol in response to user inhalation. In other
implementations
there may not be an inhalation sensor for detecting when a user is inhaling in
the device to
automatically trigger aerosol generation and instead power may be supplied to
the vaporiser
in response to a user manually activating the button 14 / switch to trigger
aerosol generation.
In still other implementations there may not be a user input button 14. In
some of these
implementations control circuitry 20 for controlling and monitoring the
operation of the non-
combustible aerosol provision system may continually monitor an inhalation
sensor and may
activate the device in response to a determination that the user is inhaling.
The outer housing 12 may be formed, for example, from a plastics or metallic
material and in
this example has a circular cross-section generally conforming to the shape
and size of the
consumable part 4 so as to provide a smooth transition between the two parts
at the
interface 6. In this example, the control unit has a length of around 8 cm so
the overall length
of the non-combustible aerosol provision system when the consumable part and
control unit
are coupled together is around 12 cm. However, and as already noted, it will
be appreciated
that the overall shape and scale of an non-combustible aerosol provision
system
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implementing an embodiment of the disclosure is not of primary significance to
the principles
described herein.
The air inlet 28 connects to an air path 30 through the control unit 2. The
control unit air path
30 in turn connects to the cartridge air path 52 across the interface 6 when
the control unit 2
and consumable part 4 are connected together. The pressure sensor chamber 18
containing
the pressure sensor 16 is in fluid communication with the air path 30 in the
control unit 2 (i.e.
the pressure sensor chamber 18 branches off from the air path 30 in the
control unit 2).
Thus, when a user inhales on the mouthpiece opening 50, there is a drop in
pressure in the
pressure sensor chamber 18 that may be detected by the pressure sensor 16 and
also air is
drawn in through the air inlet 28, along the control unit air path 30, across
the interface 6,
through the aerosol generation region in the vicinity of the vaporiser 65
(where an aerosol
generated from the aerosolisable material becomes entrained in the air flow
when the
vaporiser is active), along the cartridge air path 52, and out through the
mouthpiece opening
50 for user inhalation.
The battery 26 in this example is rechargeable and may be of a conventional
type, for
example of the kind normally used in non-combustible aerosol provision systems
and other
applications requiring provision of relatively high currents over relatively
short periods. The
battery 26 may be recharged through a charging connector in the control unit
housing 12, for
example a USB connector.
The user input button 14 in this example is a conventional mechanical button,
for example
comprising a spring mounted component which may be pressed by a user to
establish an
electrical contact. In this regard, the input button may be considered to
provide a manual
input mechanism for the non-combustible aerosol provision system, but the
specific manner
in which the button is implemented is not significant. For example, different
forms of
mechanical button or touch-sensitive button (e.g. based on capacitive or
optical sensing
techniques) may be used in other implementations. The specific manner in which
the button
is implemented may, for example, be selected having regard to a desired
aesthetic
appearance.
The display 24 is provided to give a user a visual indication of various
characteristics
associated with the non-combustible aerosol provision system, for example
current power
and / or temperature setting information, remaining battery power, and so
forth. The display
may be implemented in various ways. In this example the display 24 comprises a
conventional pixilated LCD screen that may be driven to display the desired
information in
accordance with conventional techniques. In other implementations the display
may
comprise one or more discrete indicators, for example LEDs, that are arranged
to display the
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desired information, for example through particular colours and / or flash
sequences. More
generally, the manner in which the display is provided and information is
displayed to a user
using the display is not significant to the principles described herein. Some
embodiments
may not include a visual display and may include other means for providing a
user with
information relating to operating characteristics of the non-combustible
aerosol provision
system, for example using audio signalling or haptic feedback, or may not
include any
means for providing a user with information relating to operating
characteristics of the non-
combustible aerosol provision system.
The control circuitry 20 is suitably configured / programmed to control the
operation of the
non-combustible aerosol provision system to provide functionality in
accordance with
embodiments of the disclosure as described further herein, as well as for
providing
conventional operating functions of the non-combustible aerosol provision
system in line with
the established techniques for controlling such devices. The control circuitry
(processor
circuitry) 20 may be considered to logically comprise various sub-units /
circuitry elements
associated with different aspects of the non-combustible aerosol provision
system's
operation in accordance with the principles described herein and other
conventional
operating aspects of non-combustible aerosol provision systems, such as
display driving
circuitry and user input detection. It will be appreciated the functionality
of the control
circuitry 20 can be provided in various different ways, for example using one
or more suitably
programmed programmable computer(s) and / or one or more suitably configured
application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s)
configured to provide
the desired functionality.
As is common for non-combustible aerosol provision systems, the non-
combustible aerosol
provision system of Figure 1 supports three basic operating states, namely an
"off" state, an
"on" state, and a "standby" state.
In the off state, the non-combustible aerosol provision system is unable to
generate aerosol
(i.e. the power supply control circuitry is prevented from supplying power to
the vaporiser /
heater in the off state). The non-combustible aerosol provision system may,
for example, be
placed in the off state between use sessions, for example when the non-
combustible aerosol
provision system might be set aside or placed in a users pocket or bag.
In the on (or active) state, the non-combustible aerosol provision system is
actively
generating aerosol (i.e. the power supply control circuitry is providing power
to the vaporiser
/ heater). The non-combustible aerosol provision system will thus typically be
in the on state
when a user is in the process of inhaling aerosol from the non-combustible
aerosol provision
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In the standby state the non-combustible aerosol provision system is ready to
generate
aerosol (i.e. ready to apply power to the electric heater) in response to user
activation, but is
not currently doing so. The non-combustible aerosol provision system will
typically be in the
standby state when a user initially exits the off state to begin a session of
use (i.e. when a
user initially turns on the non-combustible aerosol provision system), or
between uses during
an ongoing session of use (i.e. between puffs when the user is using the non-
combustible
aerosol provision system). It is more common for non-combustible aerosol
provision systems
using liquid aerosolisable material to revert to the standby mode between
puffs, whereas for
non-combustible aerosol provision systems using solid aerosolisable material
may more
often remain on between puffs to seek to maintain the aerosolisable material
at a desired
temperature during a session of use comprising a series of puffs.
To generate an aerosol using the vapour provision system of Figure 1,
electrical power from
the battery 26 is supplied to the heater 65 under control of the control
circuitry 20. When the
non-combustible aerosol provision system is on, i.e. actively generating an
aerosol, power
may be supplied to the heater in a pulsed fashion, for examples using a pulse
width
modulation (PWM) scheme to control the level of power being delivered. Thus,
the power
supplied to the electric heater during a period of aerosol generation may
comprise an
alternating sequence of on periods during which power is connected to the
electric heater
and off periods during power is not connected to the electric heater. The
cycle period for the
pulse width modulation (i.e. the duration of a neighbouring pair of an off and
an on period) is
in this example 0.020 s (20 ms) (i.e. the pulse width modulation frequency is
50 hertz). The
proportion of each cycle period during which power is being supplied to the
heater (i.e. the
length of the on period) as a fraction of the cycle period is the so-called
duty cycle for the
pulse width modulation. In accordance with certain embodiments of the
disclosure, the
control circuitry of the non-combustible aerosol provision system may be
configured to adjust
the duty cycle for the pulse width modulation to vary the power supplied to
the heater, for
example to achieve a target level of average power or to achieve a target
temperature.
As noted above, some non-combustible aerosol provision systems may include
means for
measuring a temperature of a heater for vaporising aerosolisable material.
Some of these
non-combustible aerosol provision systems may use a separate temperature
sensor for
measuring the temperature of the heater while others may measure an electrical
resistance
for the heater and use this to determine its temperature by taking account of
how electrical
resistance varies with temperature. One drawback of using a separate
temperature sensor
to measure temperature is increased structural complexity and part count. One
drawback of
solely relying on electrical resistance to measure temperature is low
sensitivity due to the
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relatively low temperature coefficient of resistance associated with some
materials
commonly used for heaters in non-combustible aerosol provision systems.
Whereas the embodiments discussed above with reference to Figure 1 have to
some extent
focused on devices having a liquid aerosolisable material, as already noted
the same
principles may be adopted for devices based on other aerosolisable materials,
for example
solid materials, such as plant derived materials, such as tobacco derivative
materials, or
other forms of aerosolisable material, such as gel, paste or foam based
aerosolisable
materials. Thus, the aerosolisable material may, for example, be in the form
of a solid, liquid
or gel which may or may not contain nicotine and/or flavourants. In some
embodiments, the
aerosolisable material may comprise an "amorphous solid", which may
alternatively be
referred to as a "monolithic solid" (i.e. non-fibrous). In some embodiments,
the amorphous
solid may be a dried gel. The amorphous solid is a solid material that may
retain some fluid,
such as liquid, within it. In some embodiments, the aerosolisable material may
for example
comprise from about 50wt%, 60wt% or 70wt% of amorphous solid, to about 90w1%,
95wt%
or 100w1% of amorphous solid.
The aerosolisable material (which may also be referred to as aerosol
generating material or
aerosol precursor material) may in some embodiments comprise a vapour- or
aerosol-
generating agent or a humectant. Example such agents are glycerol, propylene
glycol,
triethylene glycol, tetraethylene glycol, 1,3-butylene glycol, erythritol,
meso-Erythritol, ethyl
vanillate, ethyl laurate, a diethyl suberate, triethyl citrate, triacetin, a
diacetin mixture, benzyl
benzoate, benzyl phenyl acetate, tributyrin, lauryl acetate, lauric acid,
myristic acid, and
propylene carbonate.
Furthermore, and as already noted, it will be appreciated the above-described
approaches
may be implemented in non-combustible aerosol provision systems, e.g.
electronic smoking
articles, having a different overall construction than that represented in
Figure 1. For
example, the same principles may be adopted in an non-combustible aerosol
provision
system which does not comprise a two-part modular construction, but which
instead
comprises a single-part device, for example a disposable (i.e. non-
rechargeable and non-
refillable) device. Furthermore, in some implementations of a modular device,
the
arrangement of components may be different. For example, in some
implementations the
control unit may also comprise the vaporiser with a replaceable cartridge
providing a source
of aerosolisable material for the vaporiser to use to generate aerosol.
Furthermore still, in some examples the non-combustible aerosol provision
systems may
further include a flavour insert (flavouring element), for example a
receptacle (pod) for a
portion of tobacco or other material, arranged in the airflow path through the
device, for
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example downstream of the vaporiser, to impart additional flavour to aerosol
generated by
the vaporiser (i.e. what a hybrid type device).
As used herein, the terms "flavour" and "flavourant", and related terms, refer
to materials
which, where local regulations permit, may be used to create a desired taste
or aroma in a
product for adult consumers. The materials may be imitation, synthetic or
natural ingredients
or blends thereof. The material may be in any suitable form, for example, oil,
liquid, or
powder.
In accordance with certain embodiments of the disclosure an non-combustible
aerosol
provision device comprises control circuitry, a power source and an aerosol
generator
configured to generate an aerosol from the aerosolisable material, wherein the
control
circuitry performs the method of causing delivery of power from the power
source to the
aerosol generator for a aerosol generation event in response to a user input,
determining the
amount of aerosol generated from the aerosolisable material, in response to
the user input,
based on a rate of aerosol generation, wherein the rate of aerosol generation
is adjusted
based on a dynamic factor. Advantageously, by basing the determination of the
rate of
aerosol generation on a dynamic factor, a more accurate determination of
aerosol usage can
be achieved.
As noted above, some non-combustible aerosol provision systems may rely on
measurements of electrical resistance to determine abnormal conditions once an
aerosolisable material has been consumed. However as well as having low
sensitivity due to
the relatively low temperature coefficient of resistance associated with some
materials
commonly used for heaters in non-combustible aerosol provision systems, the
determination
of the temperature of the heater can be significantly affected by any variance
in the
resistance of the heater (e.g. due to manufacturing tolerances). Example
embodiments of
the disclosure instead exploit the determination of a rate of aerosol
generation which is
adjusted based on a dynamic factor to determine consumption of aerosolisable
material. In
some examples, by comparing to a known or estimated amount of aerosolisable
material
(e.g. the amount of liquid in a reservoir) the control circuitry 20 can
estimate when the
aerosolisable material has been depleted or is near depletion. By amount it is
meant a
measure of the quantity, such as mass or volume. This estimation can be useful
as it can
provide a user with information concerning the amount of aerosolisable
material in the
system, and/or assist in triggering one or more other detection mechanisms.
The rate of generation of aerosol depends upon a number of static factors
related to the
system configuration and hence the environment in which the aerosol is
produced. Static
factors include factors such as the energy supplied to the aerosolisable
material (e.g. power
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multiplied by time), the composition of the aerosolisable material, and also
factors related to
the aerosol generator (e.g. size, type) and the airflow configuration (e.g.
the dimensions of
the volume of airflow channel adjacent to the aerosol generator). The factors
are termed
"static" because they do not generally vary either during or between different
aerosol
generation events (i.e. puff events). For example, for two puffs using the
same aerosol
generator, the aerosol generator and the airflow configuration will not change
(e.g. the static
factor is a constant). In the example of energy, while power can be increased
and therefore
the rate of aerosol generation (e.g. aerosol production) is also increased,
this is still a static
variable as the rate is considered to be static in relation to the amount of
energy supplied
(e.g. systems can configured to equate 1 Joule to the production of a certain
amount of
aerosol regardless of whether that Joule is provided over 1 second or 0.5
seconds). Static
variables can be taken into account when providing a determination of the
amount of aerosol
generated from the aerosolisable material; however they provide reduced
accuracy when
used solely to determine an amount of aerosol that has been generated.
Advantageously, it has been found that the determination of the amount of
aerosol
generated from the aerosolisable material can be improved by taking into
account dynamic
factors. The factors are termed "dynamic" because they can vary between
different aerosol
generation events and/or within an aerosol generation event. For example, the
dynamic
factor can have a first value during a first aerosol generation event and a
second value
during a second aerosol generation event (e.g. the dynamic factor is a
variable). Dynamic
factors include factors such as intra-puff duration, inter-puff duration,
cumulative puff
duration, airflow rate, amount of aerosolisable material, and ambient
temperature.
The rate of aerosol generation can be dependent on the intra-puff duration
(e.g. the duration
of an aerosol generation event). The rate of aerosol generation increases as
intra-puff
duration increases. Without being bound by theory, this is considered to be
because energy
losses to the surrounding components (e.g. wick, support structures, airflow
channel walls)
decreases as the intra-puff duration increases. In some examples, intra-puff
duration is
determined by a user during a puff (for example, based on a user starting to
puff and
ceasing to puff, or on a user pressing a button and ceasing to press a
button). In some
examples, intra-puff duration is determined by a user prior to a puff (e.g. by
selecting an
inter-puff duration using a user interface prior to taking the puff).
Typically, the intra-puff
duration is between 1 and 8 seconds, and preferably between 2 and 4 seconds.
The rate of aerosol generation can be dependent on the inter-puff duration
(e.g. time
between aerosol generation events). The rate of aerosol generation decreases
as inter-puff
duration increases. Without being bound by theory, this is considered to be
because the
temperature of the aerosol generator, the aerosolisable material and the
surrounding
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components (e.g. wick, support structures, airflow channel walls) decreases as
the time
since the last puff increases. As such, if there is a shorter period of time
between two
sequential puffs then the aerosol generator, the aerosolisable material and,
to some extent,
the surrounding components have been effectively pre-heated. For substantially
long inter-
puff durations (e.g. more than 5 minutes) the effect of the inter-puff
duration on rate
becomes constant because the aerosol generator, the aerosolisable material and
the
surrounding components have reached equilibrium with their surroundings (e.g.
they have
reached ambient temperature). In some examples, when the device has been off
for a
substantial amount of time or when the aerosol generator and/or aerosolisable
material is
being used for the first time, then there will not be a suitable previous
aerosol generation
event, and instead for the purposes of determining a rate it can be considered
that any
adjustment based on the inter-puff duration is substantially zero.
The rate of aerosol generation can be dependent on the amount of aerosolisable
material.
Without being bound by theory, it is considered that aerosolisable material is
used up in
each puff and that as a result, the supply of readily available aerosolisable
material reduces
over time. For solid aerosolisable materials, waste products may accumulate
with increased
numbers of puffs and may lead to a reduction in the rate of aerosol generation
as they
absorb a certain amount of energy rather than the useful aerosolisable
material. For some
liquid aerosolisable materials the liquid is fed to the aerosol generator
through one or more
pathways or wicking materials. As liquid is used up, the pressure forcing
liquid towards the
aerosol generator can reduce (i.e. there is less liquid effectively pushing
liquid towards the
aerosol generator). The rate of aerosol generation can therefore decrease as
the rate of
resupply of liquid aerosolisable material is reduced. In some examples, the
amount of
aerosolisable material can be measured using any of a resistance-based
mechanism, a
capacitance-based mechanism, an optical-based mechanism, and a mass-based
mechanism.
The rate of aerosol generation can be dependent on the cumulative puff
duration (total time
of all puffs) for a particular aerosol generator (e.g. cumulative over the
time between the
device identifying changes of the aerosol generator). Without being bound by
theory, it is
considered that the aerosol generator can deteriorate over time and become
less efficient.
This can be particularly problematic for devices where the same aerosol
generator is used
with multiple aerosolisable materials over its lifetime. The rate of aerosol
generation can
therefore decrease with cumulative puff duration for a particular aerosol
generator.
The rate of aerosol generation can be dependent on the airflow rate through
the device, and
in particular past the aerosol generator. Without being bound by theory, it is
considered that
increased airflow leads to increased cooling of the aerosol generator, as well
as the
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aerosolisable material and the surrounding components. As such, the rate of
aerosol
generation decreases as the airflow rate increases.
The rate of aerosol generation can be dependent on the ambient temperature of
the device
and surrounding environment. Without being bound by theory, it is considered
that increased
ambient temperatures lead to an increased rate of aerosol generation because
the aerosol
generator heats up to a target temperature quicker for an equivalent power.
Furthermore, the
temperature difference between the aerosol generator and the surroundings is
less, so less
energy is lost to the surroundings.
By taking into account any one of these dynamic variables when determining the
rate of
aerosol generation, a more accurate determination of the amount of aerosol
generated
during an aerosol generation event is achieved. Furthermore, by taking into
account multiple
of these dynamic variables when determining the rate of aerosol generation,
the accuracy of
the determination of the amount of aerosol generated during an aerosol
generation event is
further improved.
Figure 2 is a flow diagram schematically representing some operating aspects
of the non-
combustible aerosol provision system of Figure 1 in accordance with certain
embodiments of
the disclosure.
The processing starts in step S21 in which the non-combustible aerosol
provision device 1 is
in a "standby" state or an "on" state Insofar as is relevant here, the
processing represented
in Figure 2 is the same regardless of whether the non-combustible aerosol
provision system
starts in the standby mode in step S21 because it has just been switched out
of the off state
to begin a session of use or because it is between puffs during an ongoing
session of use.
The manner in which the non-combustible aerosol provision system is caused to
switch from
the off state to the standby state will be a matter of implementation and is
not significant
here. For example, to transition from the off state to the standby state the
user may be
required to press the input button 14 in a particular sequence, for example
multiple presses
within a predetermined time.
In S21 the control circuitry 20 causes delivery of power from the power source
to the aerosol
generator for an aerosol generation event in response to a user input. In some
examples,
the control circuitry causes a substantially constant average power to be
delivered to the
aerosol generator.
In some examples, the power is delivered using pulse width modulation, wherein
a duty
cycle of the pulse width modulation is used to control the size of the pulse
width and,
therefore, to provide a target power. In some examples, a constant direct
current (DC) is
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applied to the aerosol generator (the control circuitry 20 may be configured
to control a DC
to DC converter to provide a target power).
In some examples, the control circuitry 20 is configured to provide power at a
first power
level for a first duration and to provide power at a second power level for a
second duration.
In some examples, the control circuitry 20 is configured to provide power
during a first
"preliminary" phase at the first level of power, and may be configured to
provide power
during a second "main" phase at the second level of power. In these examples,
the control
circuitry 20 is configured to transition between the first and second power
levels after a set
time.
In some examples, the control circuitry 20 is configured to provide power at a
first level of
power when a "normal" mode of operation is selected and to provide power at a
second level
of power when a "boost" mode of operation is selected. In these examples, the
control
circuitry 20 is configured to identify an input from the user which triggers
the transition from
the "normal" mode to the "boost" mode, or vice versa.
As previously stated, the control unit 2 can comprise a user input mechanism
such as a
button 14 or an inhalation sensor (puff detector) 16. The control circuit 20
is configured to
identify, or otherwise receive, a user input based on the user interacting
with the user input
mechanism and / or the inhalation sensor. The control circuitry 20 is
configured to control an
aspect of the device in response to the user input, such as causing the
delivery of power
from the power source to the aerosol generator in response to the user input.
In some examples, the control circuitry is configured to monitor the output
from the inhalation
sensor 16 to determine when a user is inhaling (i.e. a user input) through the
mouthpiece
opening 50 of the non-combustible aerosol provision system so that power can
be
automatically supplied to the vaporiser 65 to generate aerosol in response to
user inhalation.
In some examples a user manually activates a user input mechanism (i.e. a user
input) such
as a button 14 / switch to trigger aerosol generation (e.g. by the control
circuitry 20 causing
power to be supplied to the vaporiser 65). It will be appreciated that the
user input
mechanism may not be a button, but can be any mechanism which the user can
actuate to
cause an input. For example, the user input mechanism may be a slider, a dial,
a touch
screen etc. In some examples, the control circuitry 20 is able to receive
inputs from both an
inhalation sensor 16 and a user input mechanism and is able to select between
a first mode
and a second mode of operation based on the combined inputs.
In some examples, the duration of the aerosol generation event (i.e. the intra-
puff duration or
aerosol generation event duration) corresponds to the time in which the
control circuitry 20
receives the user input. In some examples, the time in which the control
circuitry receives
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the user input is the time in which the user input exceeds a certain threshold
(e.g. for a
inhalation sensor or a pressure sensitive button, the time in which the
pressure applied by
the user exceeds the threshold). In some examples, the intra-puff duration
(i.e. the aerosol
generation event duration) corresponds to the time between the control
circuitry 20 receiving
a first user input indicating a start point and a second user input indicating
an end point. For
example, if the user input mechanism has a number of selectable states (e.g. a
switch
having a first state and a second state), then the user can select a first
state to cause the
control circuitry to cause power to be supplied to the aerosol generator (i.e.
the start point)
and can select a second state to cause the control circuitry to stop causing
power to be
supplied to the aerosol generator (i.e. the end point).
In step S22, the control circuitry 20 determines the amount of aerosol
generated from the
aerosolisable material, where the aerosol has been generated in response to
the user input
at S21. The control circuitry 20 is configured to base the determination on a
rate of aerosol
generation, wherein the rate of aerosol generation is adjusted based on a
dynamic factor,
such as the duration of the aerosol generation event (i.e. the intra-puff
duration). As
previously stated, the rate of aerosol production is not only dependent on
static factors such
as the power supplied (e.g. a constant power does not produce a constant rate
of aerosol
generation), the composition of the aerosolisable material, or the
configuration of the device,
but is instead dependent on dynamic factors which can differ for different
aerosol generating
events and/or within a single aerosol generation event.
For example, the inter-puff duration increases the rate of aerosol generation
increases (i.e.
increased levels of aerosol are generated later on during a puff). As such,
the amount or
volume of aerosol produced during an inhalation event (i.e. a puff) is not
linearly dependent
on the intra-puff duration. Therefore to provide an improved estimate of the
amount of
aerosol generated during a puff, the change in the rate of aerosol generation
due to the
intra-puff duration can be taken into account.
Thus, the approach of Figure 2 represents an improved method of determining an
amount of
aerosol that has been produced in response to a user input (i.e. during an
inhalation or puff
event). An improved determination can be used for a plurality of reasons; for
example to
provide an improved estimate of the amount of aerosol generated over a certain
amount of
time or number of puffs, to provide an improved estimate of the amount of
aerosolisable
material remaining in a source of aerosolisable material, to determine when
the user must
conduct an action (such as changing the source of aerosolisable material
and/or a subsidiary
component e.g. tobacco pod), and / or to restrict operations (e.g. activating
the aerosol
generator) which may damage components of the system when the amount of
remaining
aerosolisable material is considered to be beneath a threshold.
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Table 1 provides results for a first liquid aerosolisable material used with
an non-combustible
aerosol provision system having an aerosol generator comprising a resistive
heater which is
supplied with liquid from a liquid reservoir by a wick extending between the
heater and the
liquid reservoir. The non-combustible aerosol provision system tested is
therefore
substantially similar to the example described in relation to Figure 1. The
non-combustible
aerosol provision system tested further comprises control circuitry configured
to cause power
to be supplied to the heater in response to an input (i.e. a laboratory
controlled input
mimicking a user input). The control circuity is configured to supply of 2.5 -
2.7J of energy
during a first constant power phase (e.g. a preheat phase), before supplying
power at 7.5 W
during a second phase using PWM. The first phase typically lasts around 200m5
dependent
mainly on the battery voltage. The second phase lasts the remainder of the
time.
In each test an equivalent liquid aerosolisable material (i.e. same
composition and amount)
was tested. The mass of the aerosol generator with liquid reservoir was
weighed, before
repeatedly activating the heater for a set duration (e.g. 3s, 4s, or 6s) with
pauses of at least
20 seconds between activations. After a series of heater activations (e.g. 20
activations) are
completed, the aerosol generator and liquid reservoir was weighed to determine
the
gravimetric quantity of liquid used. The heater was repeatedly activated with
additional
series of heater activation until it was deemed that the liquid aerosolisable
material was
depleted. The test was repeated for different set durations.
Puff duration 3 secs 4 secs 6 secs
Puffs per cartridge 228 156 89
Total mass loss, mg ¨1800 ¨1800 ¨1800
637 591 512
Total heater activation time, s [600:678] [560:642]
[490:532]
Table 1
The results show that for longer puff lengths the total time the heater needs
to be activated
to aerosolise the same amount of liquid is reduced. For example, for a
sequence of 3 second
puffs the total heater activation time was 637 seconds, for a sequence of 4
second puffs the
total heater activation time was 591 seconds, and for a sequence of 6 second
puffs the total
heater activation time was 512 seconds. Therefore there is a difference of 125
seconds
between aerosolising for 6 seconds repetitions and aerosolising for 3 seconds
repetitions.
Errors for total heater activation time values are provided in square
brackets.
The rate of mass loss (e.g. the rate of aerosol generation) can be calculated
for each
specific sequence as the total mass of the liquid before testing (-1800mg)
divided by the
total heater activation time. Therefore for a sequence of 6 second heater
activations the rate
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of mass loss was measured as 3.52 mg/s, for a sequence of 4 second activations
the rate of
mass loss was measured as 3.05 mg/s, and for a sequence of 3 second
activations the rate
of mass loss was measured as 2.83 ring/s.
Without being bound by theory, and as briefly above, it is believed that the
rate of aerosol
generation increases with time as the temperature of surrounding components
has
increased and therefore less energy is lost to them. In other words, towards
the beginning of
a puff, the surrounding components can be significantly colder than the
aerosol generator
(e.g. a heater may heat quickly to around 200 C while the surrounding
components may be
at room temperature). A temperature gradient forms between the aerosol
generator and the
surrounding components with energy flowing from the high temperature heater to
the low
temperature surroundings. Broadly speaking, the rate of energy/heat flow is
proportional to
the difference in temperatures and the heat transfer coefficients for the
various mechanisms
of heat transfer (e.g. conduction, convection). As such the rate of energy
flow to the
surroundings, which may be considered a loss, reduces as the difference in
temperatures
reduces during a puff.
For non-combustible aerosol provision systems comprising an aerosolisable
material that is
continually resupplied during aerosolisation (e.g. a liquid aerosolisable
material that is
wicked, or otherwise transported, to the vicinity of the heater), it is
further considered that the
heat lost to the surrounding components may, to some extent, pre-heat the
aerosolisable
material further from the aerosol generator. Advantageously, as a result less
energy is
required to bring the pre-heated aerosolisable material to the vaporisation
temperature (i.e.
because it is at a higher temperature to start with) than compared to an
aerosolisable
material at room temperature. Additionally for a pre-heated liquid
aerosolisable material, the
viscosity may be reduced compared to a liquid at room-temperature and
therefore resupply
of the liquid to aerosol generator is improved.
Figure 3 is a graph representing the rate of mass loss for different length
heater activations
in accordance with the results provided in Table 1. The x-axis is puff
duration in seconds and
the y-axis mass loss per second in mg/s. The term "puff duration" is used
interchangeably
with the term "aerosol generation event duration" as discussed above, and
refers to the
period of time in which a power is supplied to the aerosol generator when a
user input
indicates a user is puffing or inhaling through the system. In some examples
where a user
input is provided by a mechanism such as a button, the aerosol generation
event can also
include an initial heating period where the heater is activated but the user
has not yet started
puffing (for example, the use may depress a button as they bring the device
towards their
mouth but may not draw aerosol until a seal has been formed by their lips over
the
mouthpiece outlet).
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A dashed line labelled "expected" in Figure 3 details the expected mass loss
per second if
the mass loss was proportional to the power applied. In other words the
"expected" line is
dependent (at least in part) on a static factor relating to the power supplied
(e.g. 7.5 W)
which is constant irrespective of puff duration. Hence for examples which only
used a static
factor the expected rate of mass loss is constant for all puff durations.
A solid line labelled "measured" details a linear fit of the measured mass
loss per second.
The "measured" line differs significantly from the "expected" line,
particularly at long puff
durations. The fit of the "measured" line has the formula Y = a*X +c where a
and c are
constants, with a determining the gradient of the line and c the Y-intercept.
For the particular
tests shown, a approximately equals 0.23 and c approximately equals 2.13. The
value of c
may largely be determined by static factors such as the composition of the
aerosolisable
material and the aerosol generator type, whereas the value of a represents the
effect of
dynamic factors on the mass loss per second, such as the temperature of the
surroundings
of the heater increasing during a puff.
In some examples, the control circuitry 20 is configured to determine the
duration of the
aerosol generation event (i.e. the intra-puff duration) in which power is
supplied to an aerosol
generator and can compare the duration to the formula to obtain a rate of mass
loss for that
particular puff. The total mass loss (e.g. the amount of aerosol generated)
during that puff
can be calculated by multiplying the rate of mass loss by the duration. For
example, for a
puff of 3.5 seconds, the average rate of mass loss is 2.94 mg/s and the total
mass loss
during the puff is 10.29 mg.
In other examples, rather than calculating a rate of mass loss, the control
circuitry 20
calculates a total mass loss dependent on puff length. This removes the need
to first
calculate the rate and secondly multiply the rate by the time. However, in
contrast to the
approximately linear fit shown in Figure 3, the dependency of total mass loss
per puff length
is approximately a second order polynomial. Therefore while a second order
polynomial fit
can also be used to provide an improved estimation of the mass loss, the
mathematical
operations behind the estimation are more complicated for the control
circuitry.
The cumulative total mass loss for a sequence of puffs (of any puff length)
can be calculated
using the formula Cumulative mass loss = EPpuullfini[a x puff duration (x) +
c] xpuf f duration (x),
where puff duration (x) is the duration of a respective puffs in the series 1
to n puffs, and a
and c are predetermined constants (calculated by fitting a line to test data
as defined above).
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Similarly a remaining mass of aerosolisable material can be calculated using
the formula
Massrentõining = Mass initial ¨ EpPuu Ifinja x puff duration (x) + c] x puff
duration (x),
where Massinitiai is the initial mass of aerosolisable material.
Alternatively, the calculation can
be simplified and written as Massremaining. Massinitai - Cumulative mass loss.
It will be appreciated that while the above calculations are in terms of mass,
if the density of
a material is known then the above rates and mass amounts can be converted
into volumes.
As is shown in the above calculations, the rate of aerosol generation is
dependent on the
dynamic factor of intra-puff duration (i.e. "puff duration (x)" in the above
equations). As the
intra-puff duration increases the rate of aerosol generation (i.e. the term in
[...]) increases.
The rate of aerosol generation as calculated is an average for the whole of
the puff and is
multiplied by the puff duration to obtain the amount of aerosol generated
(e.g. the mass lost
during the aerosol generation event).
Table 2 provides results for a second liquid aerosolisable material used with
an non-
combustible aerosol provision system having an aerosol generator comprising a
resistive
heater which is supplied with liquid from a liquid reservoir by a wick
extending between the
heater and the liquid reservoir. The non-combustible aerosol provision system
tested is
therefore substantially similar to the example described in relation to Figure
1 and the
system used to provide table 1. The non-combustible aerosol provision system
tested further
comprises control circuitry configured to cause power to be supplied to the
heater in
response to an input (i.e. a laboratory controlled input mimicking a user
input). The control
circuity is configured to supply 2.5 ¨ 2.7J of energy during a first constant
power phase (e.g.
a preheat phase), before supplying power at 7.5 W during a second phase using
PWM. The
first phase typically lasts around 200m5 dependent mainly on the battery
voltage. The
second phase lasts the remainder of the time.
In each test an equivalent liquid aerosolisable material (i.e. same
composition and amount)
was tested. The mass of the aerosol generator with liquid reservoir was
weighed, before
repeatedly activating the heater for a set duration (e.g. 3s, 4s, or 6s) with
pauses of at least
20 seconds between activations. After a series of heater activations (e.g. 20
activations) are
completed, the aerosol generator and liquid reservoir was weighed to determine
the
gravimetric quantity of liquid used. The heater was repeatedly activated with
additional
series of heater activations until it was deemed that the liquid aerosolisable
material was
depleted. The test was repeated for different set durations.
Table 2
Puff duration 3 secs 4 secs 6 secs
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Puffs per cartridge 265 179 101
Total mass loss, mg ¨1950 ¨1950 ¨1950
Total heater activation time, s 795 716 606
The results also show, similarly to Table 1, that for longer puff lengths, the
total time the
heater needs to be activated to aerosolise the same amount of liquid is
reduced. For
example, for a sequence of 3 second puffs the total heater activation time was
795 seconds,
for a sequence of 4 second puffs the total heater activation time was 716
seconds, and for a
sequence of 6 second puffs the total heater activation time was 606 seconds.
Therefore
there is a difference of 189 seconds between aerosolising for 6 seconds
repetitions and
aerosolising for 3 seconds repetitions.
The rate of mass loss (e.g. the rate of aerosol generation) can be calculated
for each
specific sequence as the total mass of the liquid before testing (-1950mg)
divided by the
total heater activation time. Therefore for a sequence of 6 second heater
activations the rate
of mass loss was measured as 3.22 mg/s, for a sequence of 4 second activations
the rate of
mass loss was measured as 2.72 mg/s, and for a sequence of 3 second
activations the rate
of mass loss was measured as 2.45 mg/s. Additionally, a linear fit of the
measured mass
loss per second, using the formula Y = a*X +c, leads to a determination of a
as
approximately equal to 0.25 and c as approximately equal to 1.70.
As previously stated, the value of c may largely be determined by static
factors such as the
composition of the aerosolisable material and the aerosol generator type. As
the first
aerosolisable material (Table 1) is different to the second aerosolisable
material (Table 2),
the value of c has changed.
The rate of aerosol generation is also dependent on the dynamic factor of
intra-puff duration
(i.e. "puff duration (x)" in the above equations) in line with the example of
Table 1, albeit with
different constant a and c being used to calculate the rate.
While Tables 1 and 2, Figure 3 and the associated text are concerned with the
effect of the
intra-puff duration, it will be appreciated that the control circuitry can be
configured to
determine the rate of aerosol generation using these and other dynamic factors
based on
similar calculations. For example, the dependence of the rate of aerosol
generation on any
of intra-puff duration; inter-puff duration; cumulative puff duration, airflow
rate, amount of
aerosolisable material, and ambient temperature can first be established (e.g.
empirically
using laboratory tests). The dependence can then be fitted using a function
such as a
polynomial function (e.g. a linear or quadratic function), an exponential
function, or a
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logarithmic function. It will be appreciated that other functions known in the
art can be used
instead. The parameters relating to the fit can then be used by the control
circuitry to
determine the rate of the aerosol generation for the particular dynamic
factor.
A similar method can be used when determining multiple dynamic factors. The
combined
dependence (i.e. multi-variate dependence) the rate of aerosol generation on
any two or
more of intra-puff duration; inter-puff duration; cumulative puff duration,
airflow rate, amount
of aerosolisable material, and ambient temperature can first be established
(e.g. empirically
using laboratory tests). The combined dependence can then be fitted using a
function. The
parameters relating to the fit can then be used by the control circuity 20 to
determine the rate
of the aerosol generation for the two or more dynamic factors.
In some examples, the control circuitry 20 causes power to be delivered from
the power
source to the aerosol generator at a first substantially constant average
level during a first
phase and at a second substantially constant average level during a subsequent
main
phase. The inter-puff duration can be considered a third "relax" phase.
Different dynamic factors may affect the aerosol generation rate differently
in these phases.
For example, the rate of aerosol generation may be particularly effected in
the second phase
by the amount of aerosolisable material in the system, since the second phase
can be
relatively long compared to the first phase and is therefore more sensitive to
changes in
remaining aerosolisable material. In some examples, the control circuitry 20
calculates an
average rate of aerosol generation across the first and second phases (e.g.
the approach
taken in relation to Table 1 and 2 above), while in other examples the control
circuitry
calculates a first rate of aerosol generation in the first phase and a second
rate of aerosol
generation in the second phase. The first and second rates of aerosol
generation can be
average rates for the duration of those phases.
In some examples, the control circuitry 20, and/or a separate device, can be
configured to
calculate a usage amount. The usage amount may be a cumulative amount of
aerosol
generated from the aerosolisable material and / or a remaining amounting of
aerosol that
can be generated from the aerosolisable material. Examples of calculation of a
cumulative
amount and of a remaining amount are provided in the text associated with
Table 1 in
relation to intra-puff duration. In some examples, the control circuitry, and
/or the separate
device, is configured to define an upper and/or lower estimate for the usage
amount.
In some examples, the control circuitry is configured to compare the usage
amount to a
threshold, and to control an aspect of the non-combustible aerosol provision
system based
on the comparison of the usage amount to the threshold.
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For example, the aspect of the non-combustible aerosol provision system to be
controlled
may be the delivery of power to the aerosol generator. In these examples the
control circuitry
20 is configured to modulate (e.g. alter or change) the delivery of power from
the power
source to the aerosol generator in response to a subsequent user input. In
some examples,
modulating the delivery of power comprises ceasing to supply power to the
aerosol
generator in response to a subsequent user input. The control circuitry 20 may
continue to
modulate power until new aerosolisable material is provided and / or the
device is reset (e.g.
by attaching a new cartridge containing aerosolisable material or by the user
performing a
reset).
In some examples, controlling an aspect of the non-combustible aerosol
provision system
comprises controlling a detection mechanism configured to detect whether the
aerosol
generator is operating under abnormal conditions. For example, the detection
mechanism
may determine/confirm if there is aerosolisable material in proximity to the
aerosol generator.
By only controlling the detection mechanism once the above threshold has been
exceeded,
firstly power can be saved and secondly the occurrence of false positives is
reduced. In
these examples, the threshold acts as a first trigger for detection of
abnormal conditions and
the detection mechanism acts as a second trigger that abnormal conditions have
been
detected. In some embodiments, only when both trigger does the control
circuitry 20 deem
there to be abnormal conditions. The control circuitry 20 may modulate the
delivery of power
from the power source to the aerosol generator in response to the second
trigger. In
particular the control circuitry 20 may cease the supply of power or prevent
the further supply
of power to the aerosol generator until new aerosolisable material is provided
and / or the
device is reset.
In some examples, the detection mechanism is any of a resistance-based
detection
mechanism, a capacitance-based detection mechanism, and an optical-based
detection
mechanism.
In some examples, the control circuitry 20, and / or a separate device, is
configured to
calculate the usage amount as a prediction of a remaining total duration of
aerosol
generation events or a remaining number of aerosol generation events for the
aerosolisable
material, wherein the prediction is based on the usage amount and a historical
data set
relating to measured durations of previous aerosol generation events. As such,
in these
examples the usage amount is a remaining amount. Such a value may be easier to
interpret
by a user of the device (i.e. more user-friendly).
In some examples, the prediction based on the historical data set relating to
measured
durations of previous aerosol generation events comprises the prediction being
based on:
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the duration of a most recent previous aerosol generation event, an average
duration of a
plurality of previous aerosol generation events, or a predicted usage for a
plurality of
subsequent puff aerosol generation events. By a predicted usage for a
plurality of
subsequent puff aerosol generation events it is meant that the control
circuitry, and/or
separate device, makes a prediction of future usage based on the user's
behaviour
previously. The prediction may take into account factors such as day, time and
location.
In some examples the control circuitry is configured to write to the memory a
record of the
aerosol generation event. This record can be used in determining the predicted
remaining
total duration of aerosol generation events or a remaining number of aerosol
generation
events for the aerosolisable material. In some examples, the memory is
provided in the
control circuitry 20. In other examples, the memory is provided in the
consumable part 4.
In examples where there is a memory in the consumable part 3, the memory can
keep a
record of the usage amount for the consumable part. As such if the consumable
part 4 is
used with a different reusable part 2, the control circuitry of the different
reusable part can
read the memory to determine a current state of the usage amount (i.e. a
current level of
aerosolisable material). Additionally, the memory of the consumable part 4 may
indicate a
starting amount of aerosolisable material.
In some examples, the control circuity 20 is configured to provide an
indication to a user in
relation to the usage amount. By in relation, it is meant that an indication
is provided to the
user in response to a specific usage amount being reached or having been
exceeded (e.g.
after an absolute usage amount has been reached such as 1000 mg or a relative
usage
amount has been reached such as 50% of the total amount). In some examples,
the
indication is provided via visual, audio and/or haptic means. For example the
control circuitry
20 can be configured to provide haptic or audio feedback after set amounts of
aerosolisable
material have been used (e.g. every 200 mg or every 10% of the total amount).
In some examples, the control circuitry provides the indication via a display
mechanism. In
other examples, the control circuitry provides the indication via a separate
device which the
control circuitry is in communication with (e.g. wired or wireless
communication). In some
examples, the control circuity 20 is configured to communicate the indication
of the usage
amount to the user during the user input. In examples, the user may be able to
interact with
the device to obtain an indication of the current estimate of the usage amount
(e.g. via a
display). Where the indication is via a display mechanism, the indication may
comprise the
usage amount.
Thus there has also been described a method of operating an non-combustible
aerosol
provision system comprising control circuitry, a power source and an aerosol
generator
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configured to generate an aerosol from an aerosolisable material, wherein the
control
circuitry performs the method of causing delivery of power from the power
source to the
aerosol generator for an aerosol generation event in response to a user input,
and
determining the amount of aerosol generated from the aerosolisable material,
in response to
the user input, based on a determined rate of aerosol generation, wherein the
determined
rate of aerosol generation is adjusted based on a dynamic factor.
Thus there has also been described a control unit for use with an electronic
non-combustible
aerosol provision device comprising: a power source; and control circuitry
configured to
cause the delivery of power from the power source to an aerosol generator for
an aerosol
generation event in response to a user input, wherein the aerosol generator is
configured to
generate an aerosol from an aerosolisable material during the aerosol
generation event;
wherein the control circuitry is further configured to determine the amount of
aerosol
generated from the aerosolisable material, in response to the user input,
based on a
determined rate of aerosol generation, wherein the rate of aerosol generation
is adjusted
based on a dynamic factor.
Thus there has been described a non-combustible aerosol provision system
comprising:
a control unit comprising: a power source; and control circuitry configured to
cause
the delivery of power from the power source to an aerosol generator for an
aerosol
generation event in response to a user input, wherein the aerosol generator is
configured to
generate an aerosol from an aerosolisable material during the aerosol
generation event;
wherein the control circuitry is further configured to determine the amount of
aerosol
generated from the aerosolisable material, in response to the user input,
based on a
determined rate of aerosol generation, wherein the rate of aerosol generation
is adjusted
based on a dynamic factor;
the aerosol generator; and
the aerosolisable material.
Thus there has also been described a non-combustible aerosol provision means
comprising:
power source means; control means configured to cause the delivery of power
from the
power source means to an aerosol generator means for a period of time in
response to a
user input, wherein the aerosol generator means is configured to generate an
aerosol from
an aerosolisable material means; and wherein the control means is further
configured to
determine the amount of aerosol generated from the aerosolisable material
means, in
response to the user input, based on a determined rate of aerosol generation,
wherein the
rate of aerosol generation is adjusted based on a dynamic factor.
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In order to address various issues and advance the art, this disclosure shows
by way of
illustration various embodiments in which the claimed invention(s) may be
practiced. The
advantages and features of the disclosure are of a representative sample of
embodiments
only, and are not exhaustive and / or exclusive. They are presented only to
assist in
understanding and to teach the claimed invention(s). It is to be understood
that advantages,
embodiments, examples, functions, features, structures, and / or other aspects
of the
disclosure are not to be considered limitations on the disclosure as defined
by the claims or
limitations on equivalents to the claims, and that other embodiments may be
utilised and
modifications may be made without departing from the scope of the claims.
Various
embodiments may suitably comprise, consist of, or consist essentially of,
various
combinations of the disclosed elements, components, features, parts, steps,
means, etc.
other than those specifically described herein, and it will thus be
appreciated that features of
the dependent claims may be combined with features of the independent claims
in combinations
other than those explicitly set out in the claims. The disclosure may include
other inventions not
presently claimed, but which may be claimed in future.
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