Note: Descriptions are shown in the official language in which they were submitted.
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Electronic Aerosol Provision Device
Field
The present invention relates to an electronic aerosol provision device.
Background
A typical electronic aerosol provision device includes an internal air path
which
provides a channel between one or more inlets and one or more outlets. A user
of the
electronic aerosol provision device inhales on the air outlet(s) to create an
airflow through
the device along the channel from the air inlet(s) to the air outlet(s).
An electronic aerosol provision device generally also includes a source
(precursor)
material which is used for forming a vapour or aerosol. For example, some
devices include
a reservoir of liquid and a heater which is used to vaporise liquid from the
reservoir. In other
devices, a heater may be used to generate volatiles from a solid material, and
these in turn
form a vapour or liquid. In some cases, the liquid or solid material may be
provided in a
replaceable cartridge. The vapour or aerosol is usually generated in, or
migrates into, the
channel from the air inlet(s) to the air outlet(s), and is conveyed by the
airflow along the
channel and out through the air outlet(s) for inhalation by a user.
The user experience of such an electronic aerosol provision device is
dependent
upon the vapour or aerosol that exits the device for inhalation.
Summary
The invention is defined in the appended claims.
The approach described herein provides an electronic aerosol provision system
comprising an air pathway between an air inlet and an air outlet and a
vaporiser for
generating vapour into the air pathway. The air pathway between the air inlet
and the
vaporiser is configured to support laminar air flow.
The approach described herein provides an electronic aerosol provision system,
comprising an air pathway between an air inlet and an air outlet, a vaporiser
for generating
vapour into the air pathway, and a facility for adjusting the air pathway to
control turbulence
within the air pathway.
It will be appreciated that features and aspects of the invention described
above in
relation to the first and other aspects of the invention are equally
applicable to, and may be
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combined with, embodiments of the invention according to other aspects of the
invention as
appropriate, and not just in the specific combinations described above.
Brief Description of the Drawings
Various embodiments of the invention will now be described, by way of example
only,
with reference to the accompanying drawings, in which:
Figure 1 shows an example electronic aerosol provision system.
Figure 2 shows an electronic aerosol provision system having a linear airflow
channel
configured to support laminar airflow according to the approach described
herein.
Figure 3 shows distributions of aerosol particle sizes generated by an
electronic
aerosol provision system such as shown Figure 1.
Figure 4 shows distributions of aerosol particle sizes generated by an
electronic
aerosol provision system such as shown Figure 2.
Figure 5 shows an electronic aerosol provision system having a smoothly curved
airflow channel configured to support laminar airflow according to the
approach described
herein.
Figure 6 shows an electronic aerosol provision system having a facility for
adjusting
the air pathway to control turbulence according to the approach described
herein.
Figure 7 shows another electronic aerosol provision system having a facility
for
adjusting the air pathway to control turbulence according to the approach
described herein.
Detailed Description
Aspects and features of various examples are described herein. Some of these
aspects and features may be implemented conventionally and these may not be
described in
detail in the interests of brevity. It will be appreciated that such aspects
and features which
are not described in detail may be implemented in accordance with suitable
conventional
techniques.
The present disclosure relates to electronic aerosol provision systems, which
may
also be referred to as electronic vapour provision systems, e-cigarettes, and
so on. In the
following description, the terms "e-cigarette", "electronic cigarette",
"electronic aerosol
provision system" and "electronic vapour provision system" may be used
interchangeably
unless the context demands otherwise. Likewise the terms "device" and "system"
may be
used interchangeably, for example, an "electronic aerosol provision system"
should be
regarded as the same as an "electronic aerosol provision device", unless the
context
demands otherwise. Furthermore, as is common in this technical field, the
terms "vapour"
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and "aerosol", and related terms such as "vaporise", "aerosolise", and
"volatlise", may
likewise be used interchangeably unless the context demands otherwise.
Such electronic aerosol provision systems/devices are often provided in
modular
form, for example, comprising a control unit and a cartomiser (the latter
being a combination
of a cartridge and a vaporiser). The term electronic aerosol provision
system/device is used
herein to denote one or more modules (such as the control unit) that act
(comprise
components) to generate an aerosol or vapour. Such a system/device may be
configured to
receive one or more additional modules, for example, a module (cartridge)
containing liquid
or other precursor to be vaporised, or may be provided in combination with one
or more
additional modules.
One common configuration for an electronic aerosol provision system/device
having
a modular assembly is to comprise a reusable part (the main control unit) and
a replaceable
(disposable) cartridge part, also referred to as a consumable. The replaceable
cartridge part
often contains the vapour (aerosol) precursor material and may (in some
implementations)
also contain a vaporiser (aerosoliser) to form a cartomiser. The reusable part
often contains
a power supply, for example, a rechargeable battery, and control circuitry for
the
device/system. These parts may contain further components depending on
functionality.
For example, the reusable part may contain a user interface for receiving user
input and
displaying operating status characteristics, while the replaceable cartridge
part may contain
a temperature sensor for helping to control the temperature of the vaporiser.
A cartridge part is usually electrically and mechanically coupled to a control
unit for
use. When the vapour precursor material in a cartridge is exhausted (fully
consumed), or
the user wishes to switch to a different cartridge having (for example) a
different vapour
precursor material, the cartridge may be removed from the control unit and a
replacement
cartridge provided in its place. Devices conforming to this type of two-part
modular
configuration are sometimes referred to as two-part devices.
Some of the example devices/systems described herein are based on an elongated
two-part device/system that utilises disposable cartridges. However, it will
be appreciated
that the approach described herein may also be adopted for different
configurations of an
electronic aerosol provision system/device, for example, single-part devices
or modular
devices comprising more than two parts, refillable devices and single-use
disposable
devices. In addition, the approach described herein may be applied to
devices/systems
having other geometries (not necessarily elongate), for example, based on so-
called box-
mod high performance devices that typically have more of a box-like shape.
Figure 1 is a schematic cross-sectional representation of a first electronic
aerosol
provision device 20. The e-cigarette 20 comprises two main sections, namely a
control
section 22 and a cartridge section 24. In some implementations, the cartridge
section and
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the control section are separate parts which can be detached from one another.
In normal
use, the control part 22 and the cartridge part 24 are releasably coupled
together at an
interface 26. When the cartridge part 24 is exhausted (after depletion of an
aerosol
precursor material therein), or the user wishes to switch to a different
cartridge, the cartridge
24 may be detached from the control part 22. The detached cartridge may then
be disposed
of (if fully depleted) and a replacement cartridge coupled to the control
part. Another
possibility is that the same cartridge part 24 may be refilled and re-attached
to the control
part 22. In other implementations, the cartridge part 24 might be refillable
in situ, i.e. while
still attached to the control part 22 (in which case the cartridge section 24
might potentially
be permanently attached to the control section 22).
The interface 26 generally provides a structural (mechanical), electrical and
airflow
path connection between the control section 22 and the cartridge section 24.
For example,
the interface 26 may provide appropriately arranged electrical contacts for
establishing
various electrical connections between the two sections. Likewise, the
interface may
support (define) an airflow channel (path) between the two sections as
appropriate.
It will be appreciated that other implementations of the electronic aerosol
provision
system 20 may have a different configuration; moreover, different features
from different
implementations as described herein may be mixed together as appropriate. For
example,
in some implementations, the control section 22 and the cartridge section 24
might be fixed
together (rather than being detachable); as noted above, this might be the
case when the
cartridge section 24 is re-fillable in situ. In some implementations, a
vaporiser may be
provided in the control section 22 rather than in the cartridge section 24, in
which case the
interface 26 might be configured to support the transfer of a vapour precursor
(such as a
liquid) from the cartridge section 24 to the control section 22 ¨ but without
necessarily
supporting the transfer of electrical power from the control section 22 to the
cartridge section
24. In some implementations, the interface 26 may support a wireless transfer
of power
from the control section to the cartridge section, for example, based on
electromagnetic
induction. In this case, a direct physical (electrical) connection between the
control section
22 and the cartridge section 24 may not be provided. Furthermore, in some
.. implementations, the airflow path through the electronic aerosol provision
device 20 might
not go through the control section 22, hence the interface 26 might not
include an airflow
channel connection between the control section 22 and the cartridge section
24. The skilled
person will be aware of various other potential modifications.
In the example of Figure 1, the cartridge section 24 comprises a cartridge
housing 62
which may be made of plastic or any other suitable material. The cartridge
housing 62
supports other components of the cartridge section 24 and provides a
mechanical interface
with the control section 22 as part of interface 26. The cartridge section
includes an airflow
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channel (or pathway) 72 and a mouthpiece 70 which defines an air outlet 71
from the airflow
channel 72.
VVithin the cartridge housing 62 is a reservoir 64 that contains a liquid to
provide a
vapour precursor material; this is often referred to as an e-liquid. The
liquid reservoir 64 in
the device of Figure 1 has an annular shape about (around) the airflow channel
72. The
shape of the reservoir 64 is defined by an outer wall, provided by the
cartridge housing 62,
and an inner wall that forms the outside or boundary of the airflow channel 72
through the
cartridge section 24. The reservoir 64 is closed at each end to retain the e-
liquid, by
mouthpiece 70 at the downstream end of the cartridge section 24 and by the
housing 62
forming interface 26 at the upstream end.
The cartridge section 24 further comprises a wick (liquid transport element)
66 and a
heater (vaporiser) 68. In the device shown in Figure 1, the wick 66 extends
transversely
across the cartridge airflow channel 72, i.e. perpendicular to the airflow
direction along
channel 72. Each end of the wick is configured to draw liquid from the
reservoir 64 through
one or more openings in the inner wall of the liquid reservoir 64. The e-
liquid infiltrates the
wick 66 and is drawn along the wick 66 by capillary action (i.e. wicking). The
heater 68 may
comprise an electrically resistive wire coiled around the wick 66, for example
a nickel
chrome alloy (Cr20Ni80) wire, and the wick 66 may comprise a glass fibre
bundle or a cotton
fibre bundle. Many other options will be apparent to the skilled person; for
example, the wick
might be made of ceramic, the wick and heater coil might be arranged
longitudinally rather
than transversely, there might be multiple heater coils 68, there might be
multiple wicks 66,
the heater 68 may have a planar configuration, and so on.
During use, electrical power may be supplied to the heater 68 to vaporise an
amount
of e-liquid (vapour precursor material) drawn to the vicinity of the heater 68
by the wick 66.
The vaporised e-liquid then becomes entrained in air drawn along the cartridge
airflow
channel 72 towards the mouthpiece outlet 70 for user inhalation. The rate at
which e-liquid
is vaporised by the vaporiser (heater) 68 generally depends on the amount of
power
supplied to the heater 68, as well as the wicking or liquid transport capacity
of wick 66. In
some devices, the rate of vapour generation (the vaporisation rate) can be
adjusted by
changing the amount of power supplied to the heater 68, for example through
the use of
pulse width and/or frequency modulation techniques. In general, the e-liquid
vapour formed
by the heater 68 cools in the airflow channel 72 and at least partially
condenses into
particles (small droplets of liquid), thereby forming an aerosol. It is this
aerosol that is then
inhaled by a user through mouthpiece outlets 71.
The control section 22 shown in Figure 1 comprises an outer housing 32 with an
opening that defines an air inlet 48 for the e-cigarette 20, a battery 46 for
providing electrical
power to operate the e-cigarette 20, control circuitry 38 for controlling and
monitoring the
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operation of the e-cigarette 20, a user input button 34 and a visual display
indicator 44. The
outer housing 32 is configured to receive the cartridge section 24, thereby
providing a
smooth integration (union) of the two sections or parts at the interface 26.
For example, the
outer housing 32 may include clips and/or slots and/or any other suitable
engagement
features for receiving corresponding features of the cartridge section 24.
The battery 46 is generally rechargeable such as through a charging connector
in the
control section housing 32, e.g. a USB connector (not shown in Figure 1). The
user input
button 34 may be used to perform various control functions. The display 44 may
(for
example) comprise one or more LEDs for displaying information about the charge
status of
.. the battery 46 or any other suitable information or indication. In some
implementations, the
user input button 34 and the display 44 may be integrated as a single
component. The
control circuitry 38 is suitably configured (programmed) to control the
operation of the
electronic cigarette, for example to regulate the supply of power from the
battery 46 to the
heater 68 for generating vapour.
The air inlet 48 connects to an airflow path 50 through the control section
22. The
control part section path 50 in turn connects to the cartridge airflow channel
72 via the
interface 26 when the control part 22 and cartridge part 24 are connected
together. Thus,
when a user inhales on the mouthpiece 70, air is drawn in through the air
inlet 48, along the
control section air path 50, through the interface 26, along the cartridge
airflow channel 72,
and out through the opening of the mouthpiece 70 for user inhalation. In the
example of
Figure 1, the airflow path 50 is configured so that the airflow through air
inlet 48 is
perpendicular to the airflow through the air outlet 71 during a user
inhalation. In particular,
the air inlet 48 is arranged on a side of the outer housing 32 (rather than
the base). Such an
air inlet may be termed a side hole. The airflow path 50 incorporates a corner
or angle
whereby the airflow during an inhalation transitions sharply from a first
direction of airflow
from the air inlet 48 to the corner to a second direction of airflow from the
corner to the
interface 26. As can be seen in Figure 1, the second direction of travel is
perpendicular to
the first direction of travel.
Figure 2 is a schematic cross-sectional representation of a second electronic
aerosol
provision device 200. The components of the e-cigarette 200 of Figure 2 are
generally the
same as or similar to those described in relation to the Figure 1 (and
labelled with like
reference numbers), and so these components will not be discussed again.
However, in
contrast to the first e-cigarette 20 of Figure 1, which comprises a side hole
air inlet 48, the
second e-cigarette 200 of Figure 2 comprises an air inlet 248 in the base (or
bottom) of the
e-cigarette (where the orientation of an e-cigarette is defined in the
conventional manner
such that the mouthpiece 71 is at the top). VVith this location for the air
inlet 248, the control
section airflow pathway 250 and the cartridge section airflow pathway 72 are
coaxially
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aligned such that there is a straight air path along the length of the airflow
channel. Thus as
shown in Figure 2, the airflow channels 250, 72 of electronic vapour provision
device 200 are
aligned such that airflow through the device from the air inlet 248 to the
vaporiser 68 and
then out through the mouthpiece 70 follows a substantially straight line
(linear) pathway, i.e.
heading in substantially a single direction, without changing direction,
curving, bending, etc..
Although Figure 2 shows one example in which the airflow pathways in the
control
section 22 and in the cartridge section 24 have a coaxial (co-aligned)
configuration, it will be
appreciated that such a configuration may be achieved differently in other
implementations.
Furthermore, while e-cigarette 200 is shown as having two modules (cartridge
part 24 and
control part 22), other implementations with a coaxial configuration for
airflow pathways 52
and 72 may be implemented as a one-piece device, or else as a system
comprising more
than two modules.
The straight (linear) configuration of the airflow channel 250 through the
control
section 22 in Figure 2, compared with the angled (cornered) configuration in
the airflow
channel 50 of e-cigarette 20 in Figure 1, helps to support a laminar airflow
within the channel
250. In a laminar airflow (also referred to herein as a linear airflow), the
air generally all
flows in parallel in the same direction. For example, for laminar airflow
along a cylindrical
pipe, all the air flows in parallel in an axial direction along the pipe. The
airflow velocity
along the pipe has a radial profile according to distance from the centre of
the pipe. The air
flowing along the central axis of the pipe flows most quickly, while the
airflow velocity then
gradually drops with radial distance away from the centre to a zero velocity
adjacent the
edge or wall of the pipe in a region referred to as the boundary layer.
In contrast to laminar flow, the presence of features such as corners, bends,
obstructions, etc. along an airflow path generally introduces turbulence into
the airflow. This
turbulent airflow (also referred to herein as non-linear airflow) is created
by, and reflects,
localised variations in air pressure and other instabilities. For example, air
flowing around
(but close to) an obstruction may have a higher pressure than air flowing
further away from
the obstruction; this may then be balanced by a region of relatively low
pressure immediately
after the obstruction. Localised movements of air in effect seek to rebalance
the air pressure
variations, and thereby introduce turbulence into the airflow.
Note that turbulence may also arise even in an axially aligned channel shown
in
Figure 2. For example, if the air is pushed through a pipe too quickly (i.e.
with too great a
pressure difference), the high level of radial shear resulting from different
axial velocities at
different radial distances out from the centre of the channel disrupts the
airflow, leading to
instabilities and other forms of turbulence.
A dimensionless parameter known as the Reynolds number (R) is often used to
characterise the laminar and turbulent flow regimes. The Reynolds number is
defined as
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R=uL/v, where u is the flow speed, v the viscosity, and L is a linear scale
size of the flow
(this might be the diameter of a pipe, for example). A low Reynolds number
will generally
produce laminar flow, while a high Reynolds number will generally produce
turbulent flow.
The transition between laminar flow and turbulent flow might typically occur
for R in the
range 2000-3000 (although this transition point is typically sensitive to
various factors, and
may lie outside the above range in some circumstances). Note that increasing
the flow
speed increases the Reynolds number, and hence may induce a transition to
turbulent flow,
as noted above. In contrast, increasing the viscosity will decrease the
Reynolds number;
this can be regarded as a higher viscosity damping out turbulent motion.
Figures 3 and 4 are graphs showing the frequency distributions of particle
sizes
produced by the first and second example e-cigarettes, namely the side-hole
device 20 of
Figure 1 and the linear flow device 200 of Figure 2 respectively. The particle
size refers to
the size of particles or droplets in the vapour or aerosol exiting the device
through air outlets
71. Each graph shows ten repeated measurements of the particle size
distribution.
Statistical summaries of the frequency distribution of the particle sizes for
each
measurement are provided in Tables 1 and 2 below.
........... Date-Time . ,
....... 201? 1
4 7,16 17, :32 1? ..52S 1 7 -12
,L = = =
__ . =
.... .1
= .. 4. 4 7.16 16 1 7 1 .2f.:.,=1= 1 ..; :
,
=.= 2017 -1,";. 17 1 204 r1 f) 001
I f:
1-7 ... .. . 77
iv: I 1 7.1 __
........................ r,11 2272 171.204
Table 1: "Side-hole" e-cigarette.
= . = õ. . .
= I 4 De:-. .17.. 3 1. = 1 214 r µ: 1
O. fs.'.).1 I 1 =.'6
;'=,1 14 .1-11 .17121,1 zi; I. 1 .1, 0 iXrt 2 a
..."?.7 1.2.24
Y)1 76.
= 1 2 1 rl =)t-31 1
2 .!;
21:1 ?=-= 1 1214 I I 7 0.5:01
r:$1K 1 5 171 214 ai
14 .1 7 1 2 1..:1= a.!µ. ri I
........ . :
7.12.C:1=. 21 1 0.001 4 a '3(.3
9? 2.47 .õ.õ..:
Table 2: "Direct linear flow" e-cigarette.
The final three columns of each Table define parameters of the particle size
distribution for that measurement. Thus in the first line of Table 1,
Dx(10)=0.39 implies that
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10% of the particles have a size less than 0.39 microns (pm), Dx(50)=1.12
implies that 50%
of the particles have a size less than 1.12 microns (pm) (i.e. this is the
median size), and
Dx(00)=2.56 implies that 90% of the particles have a size less than 2.56
microns (pm). A
comparison of Figures 3 and 4 (and the associated tables) clearly shows that
the particle
sizes are generally smaller for a direct linear flow e-cigarette (such as
shown in Figure 2)
than for a side-hole e-cigarette (such as shown in Figure 1). It is also
suggested that the
direct linear flow measurements of Figure 4 produce a slightly tighter (more
compact)
distribution than the side-hole measurements of Figure 3.
VVithout being bound by theory, it is considered that the laminar (non-
turbulent)
airflow may form an aerosol having a smaller particle size than the non-
laminar (turbulent)
airflow because the turbulence causes more collisions between aerosol
particles, and such
collisions may lead to coagulation between particles and hence a growth in
particle size. In
contrast, when the airflow is laminar, coagulation among particles might be
reduced since
the airflow is substantially all in parallel, aligned with the axial
direction. Consequently, there
is less mixing in the airflow, and hence less potential for coagulation. It is
also possible that
turbulence brings more vapour into contact with particles, and hence leads to
a faster
condensation of vapour onto the particles (compared with laminar flow),
thereby leading to a
larger particles. This faster condensation of vapour onto the existing
particles may occur in
addition to, or in place of, the faster coagulation of particles.
It has been found that an enhanced user experience can be achieved by an
electronic vapour provision system that generally provides an aerosol having a
smaller
particle size for inhalation by the user. Without being bound by theory, this
user preference
for a smaller particle size may arise from one or more factors, such as easier
absorption of
the particles by tissue, increased lightness and/or diffusiveness of the
particles, greater
uniformity (consistency) of the particles, increased travel distance of the
particles, etc..
In view of this user preference, the airflow configuration of the e-cigarette
200 of
Figure 2 is advantageous with respect to the airflow configuration of the e-
cigarette 20 of
Figure 1, because the straight airflow channel 250 of Figure 2 helps to
provide laminar
airflow, and hence a smaller particle size, compared with the angled airflow
channel 50 of
Figure 1. In practice, in many actual devices, the airflow may have both
laminar and
turbulent components. Increasing the proportion of laminar components at the
expense of
the turbulent components should still help promote a reduced particle size and
hence an
improved user experience. Accordingly, the benefits of providing a laminar
flow are not
binary (all or nothing), but rather can be realised by incrementally
increasing the proportion
of laminar flow in a given device.
Figure 5 is a schematic cross-sectional representation of a third electronic
aerosol
provision device 500. The components of the e-cigarette 500 of Figure 5 are
generally the
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same as or similar to those described in relation to the Figure 1 (and
labelled with like
reference numbers), and so these components will not be discussed again. In
contrast to
the example e-cigarette 20 of Figure 1, which comprises a side hole air inlet
48 with an
angled airflow channel 50, and also in contrast to the example e-cigarette 200
of Figure 2,
which comprises an air inlet 248 in the base (or bottom) of the e-cigarette
200 to provide a
straight line (linear) airflow channel 250, the e-cigarette 500 of Figure 5
comprises an airflow
pathway 550 in the control section 22 which is side-opening 548 (like the e-
cigarette 20 of
Figure 1), but having a smooth, continuous curve for the airflow channel 550
between the air
inlet 548 (side-hole) and the interface 26.
Configuring the airflow pathway 550 to have such a continuous curve, rather
than a
sharp corner or angle, helps to support laminar air flow. Thus implementing an
air pathway
550 which imparts a gradual change in direction of the airflow allows the
device to comprise
a side-hole but with a lower level of turbulence (if any), compared with the
configuration of
Figure 1. An example e-cigarette 500 may therefore have an airflow channel 550
with a
radius of curvature greater than 5 mm, greater than 10mm, or preferably
greater than 15mm,
to reduce (or eliminate) turbulence (compared with the configuration of Figure
1), and so
help to reduce particle size in the aerosol provided by the device.
In some implementations, the continuous curve of the airflow channel 550 may
only
extend part-way between the air inlet 548 and the interface 26. For example,
the airflow
channel 550 may have a smoothly curved portion near air inlet 548, followed by
a linear
portion near the interface 26 (or conversely, the airflow channel 550 may have
a smoothly
curved portion near the interface 26, following on from a linear portion near
the air inlet 548).
More generally, there may be more than one continuous curve and/or more than
one linear
section in the airflow channel 550. A further possibility is that a continuous
curve (or multiple
such curves) might be approximated by a sequence of short linear sections,
whereby the
change in orientation of between any two successive linear sections is small,
for example, in
the range of 1-5 degrees, so as to limit or avoid the introduction of
turbulence.
Figure 6 is a schematic cross-sectional representation of a fourth electronic
aerosol
provision device 600. The components of the e-cigarette 600 of Figure 6 are
generally the
same as or similar to those described in relation to the Figure 1 (and
labelled with like
reference numbers), and so these components will not be discussed again. In
contrast to
the e-cigarettes shown in Figures 1, 2 and 5, which have fixed airflow channel
configurations, the e-cigarette 600 of Figure 6 has an airflow pathway 650
which may be
modified to change the level of turbulence in air inhaled through the device.
In other words,
the e-cigarette 600 of Figure 6 includes a facility to adjust the air pathway
to control the
amount of turbulence within the air pathway, and hence to change the particle
size
distribution in the aerosol produced by the e-cigarette 600.
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The airflow channel 650 of e-cigarette 600 comprises two sections, a first
movable
channel section 610 and a second fixed section 610. These two sections are
joined by an
appropriate coupling or connector 615. The first movable airflow channel
section 610
therefore extends from the air inlet 648 to the coupling 615, while the second
airflow channel
section 611 extends from the coupling 615 to the interface 26. The movable
airflow channel
section 610 in effect is able to rotate about the coupling 615 to reposition
the air inlet 648. In
particular, the position of the air inlet 648 can be rotated as indicated by
the arrows between
position A and position A'. In position A', the e-cigarette 600 approximates
the side-hole
configuration shown Figure 1, while in position A the e-cigarette 600
approximates the direct
linear flow (bottom hole) configuration shown in Figure 2.
The e-cigarette 600 includes a switch or button 625 for a user to rotate the
movable
section 610 between positions A and A'. This switch 625 may be provided with a
suitable
mechanical coupling (not shown) to accomplish this rotation of the movable
section 610.
Another possibility is that the rotation of section 610 is performed using
electrical power from
battery 46 (again under the control of switch or button 625). Other actuation
mechanisms
may be implemented, including direct movement by a user of the movable section
610, in
which case button/switch 625 might be omitted.
Although the e-cigarette 600 has been described above as having two
operational
positions for movable section 610 corresponding to A and A' (so that the
position shown in
Figure 6 is transitional between these two operational positions), other
implementations may
have one or more additional operational positions intermediate A and A'. Some
implementations may allow a continuous adjustment, i.e. the movable section
610 can be
located at any desired position intermediate A and A'. It will be appreciated
that the portion
621 of the control section housing 32 in which air inlet 648 is formed will be
arranged to
accommodate the desired range of positions for the air inlet 648.
By moving the position of the air inlet 648 from position A to position A'
(through any
supported intermediate positions) an increasing level of turbulence can be
imparted to the
airflow ¨ which as described above, will generally result in an aerosol having
a larger particle
size. This provides users with control over a parameter (particle size) which
has a direct
physical impact on their experience of using the e-cigarette 600. In
particular, different
particle sizes (large or small) may be preferred by different users, or for
different cartridges,
different e-liquids, or just in different user circumstances. The use of
button 625 to control
the position of air inlet 648 by moving section 610 to adjust turbulence
provides users with a
control over aerosol particle size according to their specific preferences and
circumstances.
For example, in a first orientation, as indicated by position A, the movable
channel
section 610 is co-aligned with the remainder of the airflow channel 650, in
particular fixed
section 611, and so turbulence is minimised. In a second orientation, as
indicated by
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position A', the movable channel section 610 is now perpendicular to the
remainder of the
airflow channel 650 and so turbulence is introduced (or increased). Note that
this
mechanism allows the level of turbulence to be altered with little or no
change to the overall
flow rate. In particular, the size of the air inlet 648 and hence the amount
of air inhaled
during a puff is substantially maintained regardless of the orientation of the
movable channel
section 610, however, the particle size distribution for the puff is dependent
on (and
controlled by) the location setting of the movable channel section 610.
As described above, the orientation of the movable airflow section 610 may be
selected by a user interacting with the device through a mechanical switch 625
or similar
device such as a wheel or lever to allow the user to tailor the particle size
to his/her
particular preference. In some implementations, this adjustment of the movable
airflow
section 610 may be performed using the user input button 34 and/or the visual
display
indicator 44 (in place of, or additionally to, using switch 625). The changes
to the orientation
may be performed very quickly, for example during or between puffs
(activations of the
heater 68), thereby allowing the user to quickly adjust the particle size to a
desired setting.
A further possibility is that in some circumstances at least, the orientation
of the movable
channel section 610 may be automatically performed by the control circuitry
38, for example,
after recognising that a particular cartridge 24 containing a particular e-
liquid has been
attached to the control unit 22.
Figure 7 is a schematic cross-sectional representation of a fifth electronic
aerosol
provision device 700. The components of the e-cigarette 700 of Figure 7 are
generally the
same as or similar to those described in relation to the Figure 1 (and
labelled with like
reference numbers), and so these components will not be discussed again. More
particularly, the e-cigarette 700 of Figure 7 has a configuration which is
very similar the e-
cigarette 200 of Figure 2, but further includes, like the e-cigarette 600 of
Figure 6, a facility to
adjust the particle size distribution in the aerosol produced by the e-
cigarette 700.
Thus as shown in Figure 7, e-cigarette 700 comprises a fixed airflow pathway
750
extending to air inlet 748 using a direct linear flow configuration, the same
as for e-cigarette
200 as shown in Figure 2. However, the e-cigarette 700 further includes a
mechanism 715
(shown in schematic form in Figure 7) to alter the configuration of the air
pathway 750 so as
to modify the relative proportion of laminar and turbulent airflow within the
air pathway 750,
thereby providing some control over the resulting particle size distribution
of the aerosol
produced by the e-cigarette 700. The mechanism 715 may be operated by a user
via button
or switch 725 in a similar manner to the use of button 625 in e-cigarette 600
to move the
airflow channel section 610. Likewise, the operation of mechanism 715 might be
performed
using the user input button 34 and/or the visual display indicator 44 (in
place of, or
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additionally to, using switch 725) and/or at least partly automatically by the
control circuitry
38.
One implementation of mechanism 715 is a shaped diaphragm or aperture which
may be changed, for example, between a simple circular shape for the opening
to a star
shape (or any other more complex shape) for the opening. The circular shape
introduces
relative little turbulence, and hence supports a higher proportion of laminar
flow, whereas the
more complex (detailed) star-shaped aperture tends to introduce more
turbulence by
creating more localised variations in pressure, and so leads to a lower
proportion of laminar
flow. The switching between the different aperture shapes may be actuated, for
example,
using button or switch 725.
In other implementations, a wall feature, such as a baffle, fin or other
obstruction (or
multiple such items) may be moved into and/or out of the airflow path 750.
Inserting such a
feature can again lead to more localised pressure variations that promote the
formation of
turbulence. Accordingly, the level of turbulence (and hence the resulting
particle size) may
be controlled by adjusting the extent of the insertion or extraction of such
obstructions into
the airflow channel 750 (e.g. by using button or switch 725). A similar effect
could be
achieved, for example, by forming or flattening surface texture or other
topology on the
inside walls of the airflow channel 750.
Another potential implementation of mechanism 715 comprises a grill, grating
or
other similar structure, which may be moved into the airflow path 750 to
increase the
turbulence of the airflow. Typically the grating is formed of fine wire, or
similar, such that the
grating acts to disrupt and impart turbulence to the airflow, but does not
inhibit the airflow
rate. In some implementations, the grill 715 may be permanently located in the
airflow path
750, however, the configuration or some other property (or properties) of the
grill might be
varied, such as the size of individual openings within the grill, to change
the amount of
turbulence produced in the airflow. A further example of mechanism 715 is an
airflow
divider, which may be positioned in the airflow path 750 to divide the airflow
channel into two
or more subchannels. Both the separation of the airflow into the multiple air
channels, and
then the subsequent recombination of the airflow into a single channel, may
lead to the
formation of turbulence in the airflow. By varying the proportion of air in
each component, the
level of turbulence may be controlled.
In some implementations, the mechanism 715 may not only impact the relative
proportion of laminar to turbulent flow, but also the rate of airflow through
the e-cigarette for
a given pressure drop or strength of inhalation ¨ in effect, increasing the
resistance to draw
(RTD). For example, introducing fins or other obstructions into the airflow
will generally act
as additional RTD resistance to the airflow, in addition to increasing the
amount of
turbulence. It may be desirable however to allow a user to control the amount
of turbulence
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(and hence particle size) while making little or no change to the RTD (and
hence to the
overall flow rate). One way of achieving this is for the e-cigarette to
include a restrictor
somewhere along the overall airflow path which is the primary restriction on
the airflow
through the e-cigarette. In such a configuration, any changes in RTD caused by
different
settings of the mechanism 715 will have a relatively low impact on the overall
RTD
experienced by a user. Another approach is for the different settings of the
mechanism 715
to be designed to alter the amount of turbulence, but not the overall airflow
resistance. For
example, for the implementation discussed above using a circular aperture to
reduce
turbulence and a star-shaped aperture to increase turbulence, the sizes of the
circular and
star-shaped apertures may be arranged so as to provide the same airflow
resistance (RTD
contribution) for both apertures.
Although mechanism 715 is shown in Figure 7 as implemented in the middle of
airflow channel 750, it may instead be implemented at the air inlet 748 or the
interface 26, or
at any suitable location between the air inlet 748 and the interface 26. In
some
implementations, the mechanism 715 may comprise multiple components at various
locations along the air pathway 750. Alternatively, the mechanism 715 may
stretch along a
substantial portion (e.g. most or all) of the airflow channel 750 between the
air inlet 748 and
the interface 26. Furthermore, while the air pathway 750 shown in Figure 7 is
substantially
linear (a straight line), other implementations may have a curved air pathway,
for example,
similar to the shape shown in Figure 5 for e-cigarette 500.
As described above, the present approach provides an electronic aerosol
provision
system or device comprising: an air pathway between an air inlet and an air
outlet; and a
vaporiser for generating vapour into the air pathway. The air pathway between
the air inlet
and the vaporiser is configured to support laminar airflow.
It has been found that such a laminar airflow can lead to smaller aerosol
particles
exiting the electronic aerosol provision system, which in turn can lead to a
more favourable
user experience. It is believed (without limitation) that a laminar airflow
may produce a
smaller particle size by reducing particle coagulation and/or by reducing
vapour deposition
onto particles. Although these physical effects generally happen downstream of
the
vaporiser, it is difficult to quiesce an airflow within the electronic aerosol
provision system
which is already turbulent. Accordingly the approach described herein seeks to
prevent or
reduce the formation of turbulence upstream of the vaporiser, which then helps
to prevent or
reduce turbulence at (and downstream of) the vaporiser.
An ideal device might have laminar (non-turbulent) airflow along the entire
airflow
pathway within the device, from air inlet to air outlet. However, it may be
difficult in practice
to achieve completely laminar airflow within the device, rather the air
pathway between the
air inlet and the vaporiser may be configured to support substantially
(mostly) laminar
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airflow, for example, having at least 60%, 75%, 85%, 90% or 95% of the airflow
through the
electronic aerosol provision device being laminar.
There are various ways in which the air pathway, at least between the air
inlet and
the vaporiser, may be configured to support (mostly) laminar airflow. For
example, the air
pathway may comprise a linear (straight line) channel between the air inlet
and the
vaporiser; the absence of sharp bends or angles facilitates laminar flow. In
some cases the
air pathway between the air inlet and the vaporiser may include one or more
curved portions;
each of the one or more curved portions may have a radius of curvature greater
than 5 mm
and preferably greater than 15mm. Again, the provision of gentle curves rather
than sharp
bends or angles facilitates laminar flow (and also gives more flexibility in
the overall
geometry of the device compared with having a straight line airflow). Laminar
flow along the
air pathway between the air inlet and the vaporiser may be further facilitated
by ensuring this
pathway is substantially free of (i) obstructions, for example, protrusions,
grills, narrow
apertures, etc., and/or (ii) topology for the walls of the air pathway, for
example, surface
texturing or other features, that would introduce turbulence into airflow
along the air pathway.
It will be appreciated that a similar approach may be adopted for the portion
of the air
pathway downstream of the vaporiser in order to reduce or prevent turbulence
in this
downstream portion.
The present approach also provides an electronic aerosol provision system
(e.g.
such as described above) which comprises a facility to control turbulence
within the air
pathway. In some implementations, the facility provides at least first and
second settings,
the first setting providing an airflow with a higher proportion of laminar
flow relative to
turbulence than the second setting. As noted above, the first setting will
generally therefore
produce an aerosol having a smaller particle size than the second setting. For
example, the
.. first setting may produce an aerosol having a median particle size (e.g.
based on diameter)
that is at least 10%, preferably at least 20%, smaller than the median
particle size of an
aerosol produced by the second setting, and/or the first setting produces an
aerosol having a
median particle size less than 1 micron and the second setting produces an
aerosol having a
median particle size greater than 1 micron. (It will be appreciated that these
ratios/sizings
are given by way of example only, since they are influenced by additional
factors, such as
the nature of the vaporizer).
It will be appreciated that while some devices may have just two settings of
the
facility, other devices may have more settings; furthermore some devices may
support a
continuous range of settings between upper and lower limits. In general, the
facility may be
.. operated by a user to control turbulence by selecting an appropriate
setting, such as by
actuating a button or slider, and/or touching a touch-sensitive input device.
In this way, a
user can select a setting that provides them with the most satisfactory user
experience. In
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other cases, the facility might be alternatively (or additionally) operated on
an automatic
basis. For example, the device might detect that a particular cartridge or
cartomiser has
been installed, and set the facility to provide the most appropriate
turbulence level for this
cartridge.
There are various ways in which the facility may be implemented. For example,
in
some cases the facility might support movement of the airflow pathway such as
to introduce
or remove a linear channel between the air inlet and the vaporiser. Other ways
of changing
the turbulence level might be to use a (re)movable airflow divider to divide a
portion of the air
pathway into two or more channels; a variable aperture (or apertures) along
the pathway;
and/or one or more structures that can be introduced into or altered within
the air pathway.
Note that the facility might utilise multiple different approaches for
changing the level of
turbulence.
In some implementations, the facility is arranged to maintain a substantially
constant
airflow through the air pathway as the facility provides different levels of
turbulence. For
example, the facility may use a smooth (circular) aperture to reduce
turbulence, or a more
angled aperture, e.g. a star, to increase turbulence. The overall size of each
aperture may
then be configured such that the differently shaped apertures provide the same
resistance to
draw (and hence overall airflow). In this way, a user is able to adjust the
particle size of the
aerosol without also changing other parameters of the device, such as
resistance to draw,
which supports easier device management for a user.
***
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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