Note: Descriptions are shown in the official language in which they were submitted.
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AEROSOL PROVISION DEVICE
Technical Field
The present invention relates to an aerosol provision device.
Background
Smoking articles such as cigarettes, cigars and the like burn tobacco during
use
to create tobacco smoke. Attempts have been made to provide alternatives to
these
articles that burn tobacco by creating products that release compounds without
burning.
Examples of such products are heating devices which release compounds by
heating,
but not burning, the material. The material may be for example tobacco or
other non-
tobacco products, which may or may not contain nicotine.
Summary
According to a first aspect of the present disclosure, there is provided an
aerosol provision device defining a longitudinal axis, the device comprising:
a first coil and a second coil, wherein:
the first coil is configured to heat a first section of a heater component,
the heater component being configured to heat aerosol generating material to
generate an aerosol;
the second coil is configured to heat a second section of the heater
component;
the first coil has a first length along the longitudinal axis and the
second coil has a second length along the longitudinal axis, the first length
being shorter than the second length;
the first coil is adjacent the second coil in a direction along the
longitudinal axis; and
in use, the aerosol is drawn along a flow path of the device towards a
proximal end of the device, and the first coil is arranged closer to the
proximal
end of the device than the second coil.
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According to a second aspect of the present disclosure there is provided an
aerosol provision device defining a longitudinal axis, the device comprising:
a first inductor coil and a second inductor coil, wherein:
the first inductor coil is configured to generate a first varying magnetic
field for heating a first section of a susceptor arrangement, the susceptor
arrangement being configured to heat aerosol generating material to generate
an aerosol;
the second inductor coil is configured to generate a second varying
magnetic field for heating a second section of the susceptor arrangement;
the first inductor coil has a first length along the longitudinal axis and
the second inductor coil has a second length along the longitudinal axis, the
first length being shorter than the second length;
the first inductor coil is adjacent the second inductor coil in a direction
along the longitudinal axis; and
in use, the aerosol is drawn along a flow path of the device towards a
proximal end of the device, and the first inductor coil is arranged closer to
the
proximal end of the device than the second inductor coil.
According to a third aspect of the present disclosure, there is provided an
aerosol provision device defining a longitudinal axis, the device comprising:
a first coil and a second coil, wherein:
the first coil is configured to heat a first section of a heater component,
the
heater component being configured to heat aerosol generating material to
generate an
aerosol;
the second coil is configured to heat a second section of the heater
component;
the first coil has a first length along the longitudinal axis and the second
coil
has a second length along the longitudinal axis;
the first coil is adjacent the second coil in a direction along the
longitudinal
axis; and
the ratio of the second length to the first length is greater than about 1.1.
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According to fourth aspect of the present disclosure, there is provided an
aerosol provision device defining a longitudinal axis, the device comprising:
a first inductor coil and a second inductor coil, wherein:
the first inductor coil is configured to generate a first varying magnetic
field for heating a first section of a susceptor arrangement, the susceptor
arrangement being configured to heat aerosol generating material to generate
an aerosol;
the second inductor coil is configured to generate a second varying
magnetic field for heating a second section of the susceptor arrangement;
the first inductor coil has a first length along the longitudinal axis and
the second inductor coil has a second length along the longitudinal axis;
the first inductor coil is adjacent the second inductor coil in a direction
along the longitudinal axis; and
the ratio of the second length to the first length is greater than about 1.1.
According to fifth aspect of the present disclosure, there is provided an
aerosol
provision device defining a longitudinal axis, the device comprising:
a heating arrangement comprising a first heater component and a second
heater component, wherein:
the first heater component is configured to heat a first section of
aerosol generating material received in the aerosol provision device, thereby
to
generate an aerosol;
the second heater component is configured to heat a second section of
the aerosol generating material thereby to generate an aerosol;
the first heater component has a first length along the longitudinal axis
and the second heater component has a second length along the longitudinal
axis;
the first heater component is adjacent the second heater component in a
direction along the longitudinal axis; and
the ratio of the second length to the first length is between about 1.1 and
about 1.5.
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According to a sixth aspect of the present disclosure, there is provided an
aerosol provision device, comprising:
a first inductor coil configured to generate a varying magnetic field for
heating
a susceptor, wherein the susceptor defines a longitudinal axis and is
configured to heat
aerosol generating material to generate an aerosol;
wherein:
the first inductor coil is helical and has a first length along the
longitudinal
axis;
the first inductor coil has a first number of turns around the susceptor, and
a ratio of the first number of turns to the first length is between about
0.2mm-1
and about 0.5mm-1.
According to a seventh aspect of the present disclosure, there is provided an
aerosol provision device, comprising:
a first inductor coil and a second inductor coil, wherein:
the first inductor coil is configured to generate a first varying magnetic
field
for heating a first section of a susceptor arrangement, the susceptor
arrangement being
configured to heat aerosol generating material to generate an aerosol;
the second inductor coil is configured to generate a second varying magnetic
field for heating a second section of the susceptor arrangement;
the first inductor coil has a first number of turns around an axis defined by
the
susceptor;
the second inductor coil has a second number of turns around the axis; and
the ratio of the second number of turns to the first number of turns is
between
about 1.1 and about 1.8.
Further features and advantages of the invention will become apparent from the
following description of preferred embodiments of the invention, given by way
of
example only, which is made with reference to the accompanying drawings.
Brief Description of the Drawings
Figure 1 shows a front view of an example of an aerosol provision device;
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Figure 2 shows a front view of the aerosol provision device of Figure 1 with
an
outer cover removed;
Figure 3 shows a cross-sectional view of the aerosol provision device of
Figure
1;
5 Figure 4 shows an exploded view of the aerosol provision device of
Figure 2;
Figure 5A shows a cross-sectional view of a heating assembly within an aerosol
provision device;
Figure 5B shows a close-up view of a portion of the heating assembly of Figure
5A;
Figure 6 shows a first example of first and second inductor coils wrapped
around
an insulating member;
Figure 7 shows a first example of the first inductor coil;
Figure 8 shows a first example of the second inductor coil;
Figure 9 shows a diagrammatic representation of a cross section of first and
second inductor coils, a susceptor and an insulating member;
Figure 10 shows a second example of first and second inductor coils wrapped
around an insulating member;
Figure 11 shows a second example of the first inductor coil;
Figure 12 shows a second example of the second inductor coil;
Figure 13 shows a diagrammatic representation of cross section of a litz wire;
Figure 14 shows a diagrammatic representation of a top down view of an
inductor coil; and
Figure 15 shows another diagrammatic representation of a cross section of
first
and second inductor coils, a susceptor and an insulating member.
Detailed Description
As used herein, the term "aerosol generating material" includes materials that
provide volatilised components upon heating, typically in the form of an
aerosol.
Aerosol generating material includes any tobacco-containing material and may,
for
example, include one or more of tobacco, tobacco derivatives, expanded
tobacco,
reconstituted tobacco or tobacco substitutes. Aerosol generating material also
may
include other, non-tobacco, products, which, depending on the product, may or
may not
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contain nicotine. Aerosol generating material may for example be in the form
of a solid,
a liquid, a gel, a wax or the like. Aerosol generating material may for
example also be
a combination or a blend of materials. Aerosol generating material may also be
known
as "smokable material".
Apparatus is known that heats aerosol generating material to volatilise at
least
one component of the aerosol generating material, typically to form an aerosol
which
can be inhaled, without burning or combusting the aerosol generating material.
Such
apparatus is sometimes described as an "aerosol generating device", an
"aerosol
provision device", a "heat-not-burn device", a "tobacco heating product
device" or a
"tobacco heating device" or similar. Similarly, there are also so-called e-
cigarette
devices, which typically vaporise an aerosol generating material in the form
of a liquid,
which may or may not contain nicotine. The aerosol generating material may be
in the
form of or be provided as part of a rod, cartridge or cassette or the like
which can be
inserted into the apparatus. A heater for heating and volatilising the aerosol
generating
material may be provided as a "permanent" part of the apparatus.
An aerosol provision device can receive an article comprising aerosol
generating material for heating. An "article" in this context is a component
that includes
or contains in use the aerosol generating material, which is heated to
volatilise the
aerosol generating material, and optionally other components in use. A user
may insert
the article into the aerosol provision device before it is heated to produce
an aerosol,
which the user subsequently inhales. The article may be, for example, of a
predetermined or specific size that is configured to be placed within a
heating chamber
of the device which is sized to receive the article.
A first aspect of the present disclosure defines a first coil and a second
coil. The
first coil has a first length, and the second coil has a second length, where
the first length
is shorter than the second length. The first coil is arranged closer to the
proximal end of
the device. The proximal end of the device is the end which is closest to the
mouth of
the user, when the user is drawing on the device to inhale aerosol. Thus, the
proximal
end is the end towards which aerosol travels, as the user inhales.
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Both the first and second coils are arranged to heat a heater component such
as
a susceptor (possibly at different times). As will be discussed in more detail
herein, a
susceptor is an electrically conducting object, which is heatable by varying
magnetic
fields. The first coil may be a first inductor coil configured to generate a
first magnetic
field. The second coil may be a second inductor coil configured to generate a
second
magnetic field. The first coil can cause a first section of the heater
component to be
heated, and the second coil can cause a second section of the heater component
to be
heated. An article comprising aerosol generating material can be received
within the
heater component, or be arranged near to, or in contact with the heater
component. Once
heated, the heater component transfers heat to the aerosol generating
material, which
releases aerosol. In one example, the heater component defines a receptacle
and the
heater component receives the aerosol generating material.
As mentioned, the first coil may be a first inductor coil, the second coil may
be
a second inductor coil and the heater component may be a susceptor (also known
as a
susceptor arrangement). The first inductor coil is configured to generate a
first varying
magnetic field for heating a first section of a susceptor arrangement. The
second
inductor coil is configured to generate a second varying magnetic field for
heating a
second section of the susceptor arrangement.
The end of the susceptor which is closest to the proximal end of the device is
surrounded by the first, shorter coil. Once aerosol generating material is
received within
the device, aerosol generating material that is arranged towards the proximal
end of the
device is heated as a result of the first, shorter coil.
It has been found that by having a shorter coil arranged closer to the
proximal
end of the device, the phenomenon known as "hot puff' can be reduced or
avoided.
"Hot puff' is where a user's first puff on the device is too hot (i.e. the
aerosol the user
inhales is too hot). This can potentially cause discomfort or harm to the
user. Hot puff
occurs because the ratio of hot aerosol to cooler air is higher than is
desired.
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By having a shorter coil arranged closer to the distal end of the aerosol
generating material (which is heated first), a smaller volume of aerosol
generating
material is heated. This reduces the volume of aerosol that is produced than
would have
been produced had a larger volume of material been heated. This aerosol is
mixed with
a volume of ambient/cooler air in the device, and the temperature of the
aerosol is
lowered, thereby avoiding/reducing hot puff. The longer coil heats a larger
volume of
aerosol generating material to produce more aerosol, which is mixed with the
same or
similar volume of ambient/cooler air. However, compared to the aerosol
produced by
the first coil, this aerosol mixture travels further through the device and
further through
the remaining aerosol generating material before being inhaled. Because the
aerosol has
further to travel, it is additionally cooled to an acceptable level. Hot puff
can be caused
by water or water vapour in the aerosol. A shorter coil may liberate a smaller
volume
of water or water vapour. For example, in aerosol generating material with a
15% water
content, a length of about 42mm, and a mass of about 260mg, the mass of water
liberated by a coil having a first length of about 14mm is about 13mg.
In the device, a first portion of aerosol generating material is heated by the
first
section of the susceptor, and the first portion is smaller than a second
portion of aerosol
generating material that is heated by the second section of the susceptor.
The first and second lengths are measured in a direction parallel to a
longitudinal
axis of the device. In another example, the first and second lengths are
measured in a
direction parallel to a longitudinal axis, for example an insertion axis into
the device,
or a longitudinal axis of the susceptor. In general, the longitudinal axis of
the device
and the longitudinal axis of the susceptor are parallel. In other words, the
susceptor
arrangement is arranged parallel to the longitudinal axis of the device.
The first and second lengths may be chosen such that aerosol produced by the
first portion of the aerosol generating material leaves the device at a first
temperature,
and aerosol produced by the second portion of the aerosol generating material
leaves
the device at a second temperature, where the first and second temperatures
are
substantially the same.
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In certain arrangements the first and second coils are activated independently
of
each other. Thus, while the first coil is operative, the second coil may be
inactive. In
some examples the first and second coils operate at the same time for a
certain length
of time. In some examples, the device comprises a controller, and the
controller can
operate the device in two or more heating modes. For example, in a first mode,
the first
and second coils may be operated for a particular length of time, and/or heat
the aerosol
generating material to a particular temperature. In a second mode, the first
and second
coils may be operated for a different length of time, and/or heat the aerosol
generating
material to a different temperature.
In a particular example, the aerosol provision device comprises the susceptor
arrangement. In other examples, an article comprising aerosol generating
material
comprises the susceptor arrangement.
The device may further comprise a mouthpiece/opening arranged at the
proximal end of the device, wherein the first coil is positioned closer to the
mouthpiece
than the second coil. The mouthpiece may be removably affixed to an opening of
the
device, or the opening of the device may itself define a mouthpiece. In a
particular
example, an article comprising the aerosol generating material is inserted
into the
device and extends out of the opening of the device while it is being heated.
Thus, the
aerosol flows out of the opening, but is contained within the article as it
does so. In such
a case, the opening may still be said to be a mouthpiece, regardless of
whether it comes
into contact with the user's mouth in use.
In certain arrangements, an outer perimeter of the first coil is positioned
away
from the susceptor by substantially the same distance as an outer perimeter of
the
second coil. In other words, the coils do not overlap each other. Such an
arrangement
can simplify the assembly process of the device. For example, the two coils
can be
.. wrapped around an insulating member. Reference to the "outer perimeter" or
"outer
surface" of the coil means the edge/surface positioned furthest away from the
susceptor
arrangement, in a direction perpendicular to the longitudinal axis of the
device and/or
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susceptor arrangement. Similarly, reference to an "inner perimeter/surface" of
the coil
means the edge/surface positioned closest to the susceptor arrangement, in a
direction
perpendicular to the longitudinal axis of the device and/or susceptor
arrangement.
Accordingly, the first and second coils may have substantially the same
external
5 diameter.
In one example, the inner diameter of the first and/or second coils is about
10-
14mm in length, and the outer diameter is about 12-16mm in length. In a
particular
example, the inner diameter of the first and second coils is about 12-13mm in
length,
10 and the outer diameter is about 14-15mm in length. Preferably the inner
diameter of the
first and second coils is about 12mm in length, and the outer diameter is
about 14.6mm
in length. The inner diameter of a helical coil is any straight line segment
that passes
through the center of the coil (as viewed in cross section) and whose
endpoints lie on
the inner perimeter of the coil. The outer diameter of a helical coil is any
straight line
segment that passes through the center of the coil (as viewed in cross
section) and whose
endpoints lie on the outer perimeter of the coil. These dimensions can provide
effective
heating of the susceptor arrangement, while retaining a compact outer size.
In some example devices, the first and second coils are substantially
contiguous.
In other words, they are directly adjacent to each other and are in contact
with each
other. Such an arrangement can simplify the assembly process of the device. In
some
examples they are directly adjacent to each other but they are not in contact
with each
other.
In some examples the midpoint of the length dimension of the second coil is
displaced along the longitudinal axis of the device/susceptor such that it is
outside of
the first coil.
In some examples, the first and second coils being adjacent in a direction
along
the longitudinal axis can mean that the first and second coils are not aligned
along an
axis. For example, they may be displaced from each other in a direction
perpendicular
to the longitudinal axis.
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The first coil and second coil may be helical. For example, they may be wound
in a helical fashion.
The first coil may comprise a first wire, wound (helically) at a first pitch,
and
second coil may comprise a second wire, wound (helically) at a second pitch.
The pitch
is the length of the coil (measured along the longitudinal axis of the
device/susceptor/coil) over one complete winding.
The first coil and the second coil may have different pitches. This allows the
heating effect of the susceptor arrangement to be tailored for a particular
purpose. For
example, a shorter pitch can induce a stronger magnetic field. Conversely, a
longer pitch
can induce a weaker magnetic field.
In an example, the second pitch is longer than the first pitch. This can help
reduce the temperature of the produced aerosol in this area. In particular,
the second
pitch may be longer than the first pitch by less than about 0.5mm, or by less
than about
0.2mm, or more preferably by about 0.1mm.
In one arrangement, both the first and second pitches are between about 2mm
and about 4mm, or between about 2mm and about 3mm, or preferably between about
2.5mm and about 3mm. For example, the first pitch may be about 2.8mm and the
second
pitch may be about 2.9mm. It has been found that these particular pitches
provide
optimum heating of the aerosol generating material.
Alternatively, the first coil and the second coil may have substantially the
same
pitch. This can make it easier and simpler to manufacture the coils. In one
example, the
pitch is between about 2mm and about 4mm, or may be between about 3mm and
about
4mm, or may be between about 3mm and about 3.5mm, or may be greater than about
2mm or greater than about 3mm, and/or be less than about 4mm and/or less than
about
3.5mm.
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The first length (of the first coil) may be between about 14mm and about 23mm,
such as between about 14mm and about 21mm, and the second length (of the
second
coil) may be between about 23mm and about 30mm, such as between about 25mm and
about 30 mm. More particularly, the first length may be about 19mm ( 2mm) and
the
second length may be about 25mm ( 2mm). It has been found that these lengths
are
particularly suitable for providing effective heating of the susceptor, while
reducing hot
puff. In another example, the first length may be about 20mm ( 1mm) and the
second
length may be about 27mm ( 1mm).
The first coil may comprise a first wire which has a length between about
250mm and about 300mm, and the second coil may comprise a second wire which
has
a length between about 400mm and about 450mm. In other words, the length of
the
wire within each coil is the length when the coil is unravelled. For example,
the first
wire may have a length between about 300mm and about 350mm, such as between
about 310, and about 320mm. The second wire may have a length between about
350mm and about 450mm, such as between about 390mm and about 410mm. In a
particular arrangement, the first wire has a length of about 315mm, and the
second wire
has a length of about 400mm. It has been found that these lengths are
particularly
suitable for providing effective heating of the susceptor, while reducing hot
puff.
The first coil may have between about 5 and 7 turns, and the second coil may
have between about 8 and 9 turns. In other words, the first wire and the
second wire
may be wound this many times. A turn is one complete rotation around an axis.
In a
particular example, the first coil has between about 6 and 7 turns, such as
about 6.75
turns. The second coil may have about 8.75 turns. This allows the ends of the
coils to
be connected to terminals (such as on a printed circuit board) at a similar
place. In a
different example, the first coil has between about 5 and 6 turns, such as
about 5.75
turns. The second coil may have about 8.75 turns.
The first coil may comprise gaps between successive turns and each gap may
have a length of between about 1.4mm and about 1.6mm, such as about 1.5mm. The
second coil may comprise gaps between successive turns and each gap may have a
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length of between about 1.4mm and about 1.6mm, such as about 1.6mm. In some
examples the heating effect of the susceptor arrangement can be different for
each coil.
More generally, the gaps between successive turns may be different for each
coil. The
gap length is measured in a direction parallel to the longitudinal axis of the
device/susceptor/coil. A gap is a portion where no wire of the coil is present
(i.e. there
is a space between successive turns).
The first coil may have a mass between about lg and about 1.5g, and the second
coil may have a mass between about 2g and about 2.5g. For example, the first
mass
may be less than about 1.5g, and the second mass may be greater than about 2g.
In a
particular arrangement, the first coil has a mass of between about 1.3g and
about 1.6g,
such as 1.4g and the second coil has a mass of between about 2g and about 2.2g
such
as about 2.1g.
The device may further comprise a controller configured to energise/activate
the
first coil and the second coils sequentially and to energise/activate the
first coil before
the second coil. Thus, in use, the first coil is operated first, and the
second coil is
operated second.
The susceptor arrangement may be hollow and/or substantially tubular to allow
the aerosol generating material to be received within the susceptor, such that
the
susceptor surrounds the aerosol generating material.
In other examples there may be three coils, or four coils, where the coil
closest
to the mouth end of the device is shorter than each of the other coils.
In another example, the first length (of the first coil) may be between about
lOmm and about 21mm, and the second length (of the second coil) may be between
about 18mm and about 30 mm (provided the first coil is shorter than the second
coil).
In one example, the first length may be about 17.9mm ( 1mm) and the second
length
may be about 20mm ( 1mm). In another example, the first length may be about
lOmm
( 1mm) and the second length may be about 21mm ( 1mm). In another example, the
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first length may be about 14mm ( 1mm) and the second length may be about 20mm
( 1mm).
In some examples, each coil may have the same number of turns.
In some examples, the heater component/susceptor may comprise at least two
materials capable of being heated at two different frequencies for selective
aerosolization of the at least two materials. For example, a first section of
the heater
component may comprise a first material, and a second section of the heater
component
may comprise a second, different material. Accordingly, an aerosol provision
device
may comprise a heater component configured to heat aerosol generating
material,
wherein the heater component comprises a first material and a second material,
wherein
the first material is heatable by a first magnetic field having a first
frequency and the
second material is heatable by a second magnetic field having a second
frequency,
wherein the first frequency is different to the second frequency. The first
and second
magnetic fields may be provided by a single coil or two coils, for example.
Preferably, the device is a tobacco heating device, also known as a heat-not-
burn device.
As briefly mentioned above, in some examples, the coil(s) is/are configured
to,
in use, cause heating of at least one electrically-conductive heating
component/element
(also known as a heater component/element), so that heat energy is conductible
from
the at least one electrically-conductive heating component to aerosol
generating
material to thereby cause heating of the aerosol generating material.
In some examples, the coil(s) is/are configured to generate, in use, a varying
magnetic field for penetrating at least one heating component/element, to
thereby cause
induction heating and/or magnetic hysteresis heating of the at least one
heating
component. In such an arrangement, the or each heating component may be termed
a
"susceptor". A coil that is configured to generate, in use, a varying magnetic
field for
penetrating at least one electrically-conductive heating component, to thereby
cause
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induction heating of the at least one electrically-conductive heating
component, may be
termed an "induction coil" or "inductor coil".
The device may include the heating component(s), for example electrically-
5 conductive heating component(s), and the heating component(s) may be
suitably
located or locatable relative to the coil(s) to enable such heating of the
heating
component(s). The heating component(s) may be in a fixed position relative to
the
coil(s). Alternatively, the at least one heating component, for example at
least one
electrically-conductive heating component, may be included in an article for
insertion
10 into a heating zone of the device, wherein the article also comprises
the aerosol
generating material and is removable from the heating zone after use.
Alternatively,
both the device and such an article may comprise at least one respective
heating
component, for example at least one electrically-conductive heating component,
and
the coil(s) may be to cause heating of the heating component(s) of each of the
device
15 and the article when the article is in the heating zone.
In some examples, the coil(s) is/are helical. In some examples, the coil(s)
encircles at least a part of a heating zone of the device that is configured
to receive
aerosol generating material. In some examples, the coil(s) is/are helical
coil(s) that
encircles at least a part of the heating zone. The heating zone may be a
receptacle,
shaped to receive the aerosol generating material.
In some examples, the device comprises an electrically-conductive heating
component that at least partially surrounds the heating zone, and the coil(s)
is/are helical
coil(s) that encircles at least a part of the electrically-conductive heating
component. In
some examples, the electrically-conductive heating component is tubular. In
some
examples, the coil is an inductor coil.
A third aspect of the present disclosure defines a first coil and a second
coil. The
first coil has a first length, and the second coil has a second length, where
the ratio of
the second length to the first length is greater than about 1.1. The first
length is therefore
shorter than the second length and the second length is at least 1.1 times as
long as the
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first length. Accordingly, the device has an asymmetric heating arrangement of
coils.
It will be appreciated that this asymmetric heating arrangement is also
applicable to
other heating technologies, such as resistive heating, where first and second
heater
resistive heater components may replace the first and second coils.
The first coil may be a first inductor coil, the second coil may be a second
inductor coil and the heater component may be a susceptor (also known as a
susceptor
arrangement).
By having two coils of different lengths, different volumes of aerosol
generating
material are heated by each coil. For the shorter coil, a smaller volume of
aerosol is
generally produced than would have been produced had a larger volume of
material
been heated. The longer coil therefore heats a larger volume of aerosol
generating
material to produce more aerosol. Thus, by having coils of different lengths,
a desired
volume of aerosol can be released by operating the relevant coil.
In the above arrangement, the produced aerosol is mixed with substantially the
same volume of ambient/cooler air in the device, regardless of which coil
causes the
aerosol to be released. The ambient air cools the temperature of the produced
aerosol.
Depending upon which coil is arranged closer to the proximal end (mouth end)
of the
device will affect the temperature of the aerosol inhaled by the user.
It has been found that when the ratio of the second length to the first length
is
greater than about 1.1, the volume and temperature of produced aerosol can be
tailored
to suit a user's needs. In addition, the use of two heating zones provides
more flexibility
as to how the aerosol generating material is heated.
Furthermore, the shorter coil heats a shorter portion of the susceptor (and
thus a
shorter portion of the aerosol generating material) with a quicker ramp up
time.
Therefore, in a session, different sensory properties can be introduced in a
more
accented manner. For example, if the shorter coil is arranged at the mouth end
(proximal end) of the device, the first puff taken by the user can be achieved
quickly.
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If the shorter coil is arranged elsewhere, then additional sensory properties
can be
introduced quickly over background sensory properties. If the shorter coil is
at the
distal end, then a particularly pronounced sensory can be brought it at the
end of a
session, e.g. to overcome off-notes that may be generated by continued heating
of
downstream portions of the tobacco via the other coils simultaneously.
The ratio may be greater than 1.2. In a particular arrangement, the ratio is
between about 1.2 and about 3. When the radio is less than about 3, the volume
and
temperature of produced aerosol can be better tailored to suit a user's needs.
Preferably,
the ratio is between about 1.2 and about 2.2, or between about 1.2 and about
1.5. More
preferably, the ratio is between about 1.3 and about 1.4. It has been found
that this ratio
provides a good balance between the above-mentioned considerations.
The first length (of the first coil) may be between about 14mm and about 23mm,
such as between about 14mm and about 21mm. More particularly, the first length
may
be about 19mm ( 2mm). The second length (of the second coil) may be between
about
20mm and about 30 mm or between about 25mm and about 30mm. More particularly,
the second length may be about 25mm ( 2mm). It has been found that these
lengths are
particularly suitable for providing effective heating of the susceptor, to
ensure a desired
volume and temperature of aerosol is produced. In another example, the first
length
may be about 20mm ( 1mm) and the second length may be about 27mm ( lmm).
Preferably the first length is about 20mm, and the second length is about
27mm,
such that the ratio is between about 1.3 and about 1.4. These dimensions have
been
found to provide a good configuration.
In a particular arrangement, in use, the aerosol is drawn along a flow path of
the
device towards a proximal end of the device, and the first coil is arranged
closer to the
proximal end of the device than the second coil. As mentioned above, it has
been found
.. that by having a shorter coil arranged closer to the proximal end of the
device, the
phenomenon known as "hot puff' can be reduced or avoided.
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It has been found that when the ratio of the second length to the first length
is
greater than about 1.1 (and less than about 3, such as less than about 2.2, or
less than
about 1.5, or less than about 1.4), the desired temperature and volume of
aerosol can be
produced by both coils, without causing harm or discomfort for the user.
The device may further comprise a mouthpiece/opening arranged at the
proximal end of the device, wherein the first coil is positioned closer to the
mouthpiece
than the second coil. The mouthpiece may be removably affixed to an opening of
the
device, or the opening of the device may itself define a mouthpiece. In a
particular
example, an article comprising the aerosol generating material is inserted
into the
device and extends out of the opening of the device while it is being heated.
Thus, the
aerosol flows out of the opening, but is contained within the article as it
does so. In such
a case, the opening may still be said to be a mouthpiece, regardless of
whether it comes
into contact with the user's mouth in use.
In a particular example, the aerosol provision device comprises the susceptor
arrangement. In other examples, an article comprising aerosol generating
material
comprises the susceptor arrangement.
In certain arrangements, an outer perimeter of the first coil is positioned
away
from the susceptor by substantially the same distance as an outer perimeter of
the
second coil. In other words, the coils do not overlap each other. Such an
arrangement
can simplify the assembly process of the device. For example, the two coils
can be
wrapped around an insulating member. Reference to the "outer perimeter" or
"outer
surface" of the coil means the edge/surface positioned furthest away from the
susceptor
arrangement, in a direction perpendicular to the longitudinal axis of the
device and/or
susceptor arrangement. Similarly, reference to an "inner perimeter/surface" of
the coil
means the edge/surface positioned closest to the susceptor arrangement, in a
direction
perpendicular to the longitudinal axis of the device and/or susceptor
arrangement.
Accordingly, the first and second coils may have substantially the same
external
diameter.
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In one example, the inner diameter of the first and second coils are about 10-
14mm in length, and the outer diameter is about 12-16mm in length. In a
particular
example, the inner diameter of the first and second coils is about 12-13mm in
length,
and the outer diameter is about 14-15mm in length. Preferably the inner
diameter of the
first and second coils is about 12mm in length, and the outer diameter is
about 14.6mm
in length. The inner diameter of a helical coil is any straight line segment
that passes
through the center of the coil (as viewed in cross section) and whose
endpoints lie on
the inner perimeter of the coil. The outer diameter of a helical coil is any
straight line
segment that passes through the center of the coil (as viewed in cross
section) and whose
endpoints lie on the outer perimeter of the coil. These dimensions can provide
effective
heating of the susceptor arrangement.
In some example devices, the first and second coils are substantially
contiguous.
In other words, they are directly adjacent to each other and are in contact
with each
other. Such an arrangement can simplify the assembly process of the device. In
some
examples they are directly adjacent to each other but they are not in contact
with each
other.
In some examples the midpoint of the length dimension of the second coil is
displaced along the longitudinal axis of the device/susceptor such that it is
outside of
the first coil.
In some examples, the first and second coils being adjacent in a direction
along
the longitudinal axis can mean that the first and second coils are not aligned
along an
axis. For example, they may be displaced from each other in a direction
perpendicular
to the longitudinal axis.
The first coil and second coil may be helical. For example, they may be wound
in a helical fashion.
The first coil may comprise a first wire, wound (helically) at a first pitch,
and
second coil may comprise a second wire, wound (helically) at a second pitch.
The pitch
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is the length of the coil (measured along the longitudinal axis of the
device/susceptor/coil) over one complete winding.
The first coil and the second coil may have different pitches. This allows the
5 heating
effect of the susceptor arrangement to be tailored for a particular purpose.
For
example, a shorter pitch can induce a stronger magnetic field. Conversely, a
longer pitch
can induce a weaker magnetic field.
In an example, the second pitch is longer than the first pitch. This can help
10 reduce
the temperature of the produced aerosol in this area. In particular, the
second
pitch may be longer than the first pitch by less than about 0.5mm, or by less
than about
0.2mm, or more preferably by about 0.1mm.
In one arrangement, both the first and second pitches are between about 2mm
15 and
about 4mm, or between about 2mm and about 3mm, or preferably between about
2.5mm and about 3mm. For example, the first pitch may be about 2.8mm and the
second
pitch may be about 2.9mm. It has been found that these particular pitches
provide
optimum heating of the aerosol generating material.
20
Alternatively, the first coil and the second coil may have substantially the
same
pitch. This can make it easier and simpler to manufacture the coils. In one
example, the
pitch is between about 2mm and about 3mm, or may be between about 2.5mm and
about 3mm, or may be between about 2.8mm and about 3mm, or may be greater than
about 2.5mm or greater than about 2.8mm, and/or be less than about 3mm.
The first coil may comprise a first wire which has a length between about
250mm and about 300mm, and the second coil may comprise a second wire which
has
a length between about 400mm and about 450mm. In other words, the length of
the
wire within each coil is the length when the coil is unravelled. For example,
the first
wire may have a length between about 300mm and about 350mm, such as between
about 310, and about 320mm. The second wire may have a length between about
350mm and about 450mm, such as between about 390mm and about 410mm. In a
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particular arrangement, the first wire has a length of about 315mm, and the
second wire
has a length of about 400mm. It has been found that these lengths are
particularly
suitable for providing effective heating of the susceptor, while reducing hot
puff.
The first coil may have between about 5 and 7 turns, and the second coil may
have between about 8 and 9 turns. In other words, the first wire and the
second wire
may be wound this many times. A turn is one complete rotation around an axis.
In a
particular example, the first coil has between about 6 and 7 turns, such as
about 6.75
turns. The second coil may have about 8.75 turns. This allows the ends of the
coils to
be connected to terminals (such as on a printed circuit board) at a similar
place. In a
different example, the first coil has between about 5 and 6 turns, such as
about 5.75
turns. The second coil may have about 8.75 turns.
The first coil may comprise gaps between successive turns and each gap may
have a length of between about 1.4mm and about 1.6mm, such as about 1.5mm. The
second coil may comprise gaps between successive turns and each gap may have a
length of between about 1.4mm and about 1.6mm, such as about 1.6mm. In some
examples the heating effect of the susceptor arrangement can be different for
each coil.
More generally, the gaps between successive turns may be different for each
coil. The
gap length is measured in a direction parallel to the longitudinal axis of the
device/susceptor. A gap is a portion where no wire of the coil is present
(i.e. there is a
space between successive turns).
The first coil may have a mass between about lg and about 1.5g, and the second
coil may have a mass between about 2g and about 2.5g. For example, the first
mass
may be less than about 1.5g, and the second mass may be greater than about 2g.
In a
particular arrangement, the first coil has a mass of between about 1.3g and
about 1.6g,
such as 1.4g and the second coil has a mass of between about 2g and about 2.2g
such
as about 2.1g.
The device may further comprise a controller configured to energise/activate
the
first coil and the second coils sequentially and to energise/activate the
first coil before
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the second coil. Thus, in use, the first coil is operated first, and the
second coil is
operated second.
The susceptor arrangement may be hollow and/or substantially tubular to allow
the aerosol generating material to be received within the susceptor, such that
the
susceptor surrounds the aerosol generating material.
In other examples there may be three coils, or four coils. In certain
arrangements
the coil closest to the mouth end of the device is shorter than each of the
other coils.
In another example, the first length (of the first coil) may be between about
lOmm and about 21mm, and the second length (of the second coil) may be between
about 18mm and about 30 mm (provided the first coil is shorter than the second
coil).
In one example, the first length may be about 17.9mm ( 1mm) and the second
length
may be about 20mm ( 1mm). In another example, the first length may be about
lOmm
( 1mm) and the second length may be about 21mm ( 1mm). In another example, the
first length may be about 14mm ( 1mm) and the second length may be about 20mm
( 1mm).
In some examples, the heater component/susceptor may comprise at least two
materials capable of being heated at two different frequencies for selective
aerosolization of the at least two materials. For example, a first section of
the heater
component may comprise a first material, and a second section of the heater
component
may comprise a second, different material. Accordingly, an aerosol provision
device
may comprise a heater component configured to heat aerosol generating
material,
wherein the heater component comprises a first material and a second material,
wherein
the first material is heatable by a first magnetic field having a first
frequency and the
second material is heatable by a second magnetic field having a second
frequency,
wherein the first frequency is different to the second frequency. The first
and second
magnetic fields may be provided by a single coil or two coils, for example.
In some examples, each coil may have the same number of turns.
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In some examples there may be three coils, or four coils. In certain
arrangements
the coil closest to the mouth end of the device is shorter than each of the
other coils.
The device, coils or heater component described in relation to the third,
fourth
or fifth aspects may comprise any or all of the dimensions or features
described in
relation to any of the other aspects described.
A sixth aspect of the present disclosure defines a first inductor coil which
is
configured to generate a varying magnetic field for penetrating and heating a
susceptor.
The susceptor may define a longitudinal axis, and the first inductor coil has
a first length
along the longitudinal axis. Alternatively, the first inductor coil may define
a
longitudinal axis. The first inductor coil is helical, and therefore comprises
a first
number of turns around the longitudinal axis, as it is wound helically around
the
susceptor. A turn is one complete rotation about the susceptor/axis.
It has been found that when the ratio of the number of turns to the length of
an
inductor coil is between about 0.2mm-1 and about 0.5mm-1, the inductor coil
generates
a magnetic field that is particularly effective at heating a susceptor
arranged within the
.. inductor coil. In certain arrangements, such a magnetic field can cause the
susceptor to
be heated to about 250 C within less than about 2 seconds, for example. The
ratio of
the number of turns to the length of an inductor coil may be referred to as
the "turn
density", for example. An inductor coil with a turn density between about
0.2mm-1 and
about 0.5mm-1 is a good balance between ensuring effective and quick heating
(with a
higher turn density) and ensuring that the device is relatively lightweight
and relatively
inexpensive to manufacture (with a lower turn density). Moreover, a higher
turn density
can result in higher resistive losses in the wire forming the inductor coil,
and can reduce
the air-gap spacing between consecutive turns in the inductor coil. Both of
these effects
can cause the outer surface of the device to become hotter, which may be
uncomfortable
.. for a user of the device.
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In some examples, the ratio of the first number of turns to the first length
is
between about 0.2mm-1 and about 0.4mm-1, or between about 0.3mm-1 and about
0.4mm-1. Preferably the ratio of the first number of turns to the first length
is between
about 0.3mm-1 and about 0.35mm-1, such as between about 0.32mm-1 and about
0.34mm-1.
In certain examples, the first inductor coil may have a first length that is
between
about 15mm and about 21mm. In certain examples, the first inductor coil may
have a
first number of turns that is between about 6 and about 7. These lengths and
number of
turns can provide a turn density within the ranges described above.
Preferably, the first length is between about 18mm and about 21mm, and the
first number of turns is between about 6.5 and about 7. In a particular
example, the first
length is about 20mm ( 1mm) and the first number of turns is between about 6.5
and
.. about 7, such as about 6.75. Such an inductor coil is particularly well
suited to heat a
susceptor in an aerosol provision device.
The aerosol provision device may comprise a single inductor coil (i.e. the
first
inductor coil), or may comprise two or more inductor coils.
In a particular example, the device further comprises a second inductor coil
having a second length along the longitudinal axis and a second number of
turns around
the susceptor, and wherein a ratio of the second number of turns to the second
length is
between about 0.2mm-1 and about 0.5mm-1. In some examples, the ratio of the
second
.. number of turns to the second length is between about 0.2mm-1 and about
0.4mm-1, or
between about 0.3mm-1 and about 0.4mm-1. Preferably the ratio of the second
number
of turns to the second length is between about 0.3mm-1 and about 0.35mm-1,
such as
between about 0.32mm-1 and about 0.34mm-1.
Thus, the first and second inductor coils may comprise substantially the same,
or a similar turn density. In one example, the absolute difference between the
ratio of
the second number of turns to the second length and the ratio of the first
number of
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turns to the first length is less than about 0.05mm-1, or less than about
0.01mm-1, or less
than about 0.005mm-1. In another example, the percentage difference between
the ratio
of the second number of turns to the second length and the ratio of the first
number of
turns to the first length may be less than about 15%, or less than about 10%,
or less than
5 about
5% or less than about 3% or less than about 1%. Thus, when the first and
second
inductor coils comprise substantially the same turn density, the susceptor can
be heated
more evenly along its length. This avoids the aerosol generating material
being
unevenly heated, which can affect the volume, taste and temperature of aerosol
that is
being generated.
The first length of the first inductor coil may be different to the second
length
of the second inductor coil. Similarly, the first number of turns may be
different to the
second number of turns. Accordingly, although the first and second inductor
coils may
have different lengths and a different number of turns, they may still have
the same turn
density.
In certain examples the first length may greater than the second length by at
least 5mm.
In certain examples, the second inductor coil may have a second length that is
between about 25mm and about 30mm. In certain examples, the second inductor
coil
may have a second number of turns that is between about 8 and about 9. These
lengths
and number of turns can provide a turn density within the ranges described
above.
Preferably, the second length is between about 25mm and about 28mm, and the
second number of turns is between about 8.5 and about 9. In a particular
example, the
second length is about 26mm ( 1mm) and the second number of turns is between
about
8.5 and about 9, such as about 8.75. Such an inductor coil is well suited to
heat a
susceptor in an aerosol provision device.
In an alternative example, the first inductor coil may have a first length
that is
between about 15mm and about 21mm. In certain examples, the first inductor
coil may
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have a first number of turns that is between about 5 and about 6. Preferably,
the first
length is between about 17.5mm and about 18.5mm, and the first number of turns
is
between about 5.5 and about 6. In a particular example, the first length is
about 17.9mm
( 1mm) and the first number of turns is between about 5.5 and about 6, such as
about
5.75. The ratio of the first number of turns to the first length is between
about 0.3mm-1
and about 0.4mm-1. More preferably, the ratio is about 0.34 mm-1. The device
may
further comprise a second inductor coil having a second length along the
longitudinal
axis and a second number of turns around the susceptor. The second inductor
coil may
have a second length that is between about 19mm and about 24mm. In certain
examples,
the second inductor coil may have a second number of turns that is between
about 6 and
about 7. Preferably, the second length is between about 19.5mm and about
20.5mm,
and the second number of turns is between about 6.5 and about 7. In a
particular
example, the second length is about 20mm ( lmm) and the second number of
turns is
between about 6.5 and about 7, such as about 6.75. A ratio of the second
number of
turns to the second length is between about 0.3mm-1 and about 0.4mm-1. More
preferably, the ratio is about 0.38mm-1. The ratios for the first and second
inductor coils
therefore vary by about 0.04mm-1.
In a particular arrangement, in use, the aerosol is drawn along a flow path of
the
device towards a proximal end of the device, and the first inductor coil is
arranged
closer to the proximal end of the device than the second inductor coil.
In some examples, either, or both of the first and second inductor coils are
formed from litz wire which comprises a plurality of wire strands. The litz
wire may
have a circular or rectangular cross-section, for example. Preferably the litz
wire has a
circular cross section.
A litz wire is a wire comprising a plurality of wire strands which is used to
carry
alternating current. Litz wire is used to reduce skin effect losses in a
conductor, and
comprises a plurality of individually insulated wires which are twisted or
woven
together. The result of this winding is to equalize the proportion of the
overall length
over which each strand is at the outside of the conductor. This has the effect
of
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distributing the current equally among the wire strands, reducing the
resistance in the
wire. In some examples the litz wire comprises several bundles of wire
strands, where
the wire strands in each bundle are twisted together. The bundles of wires are
twisted/woven together in a similar way.
In some examples, the litz wires of the inductor coils have between about 50
and about 150 wire strands. It has been found that an inductor coil formed
with litz wire
having the above-mentioned turn density and this many wire strands is
particularly
suitable for heating a susceptor used in an aerosol provision device. For
example, the
strength of the magnetic field induced by the inductor coil is well suited to
heat a
susceptor arranged in proximity to the inductor coil.
In another example, the litz wires of the inductor coils have between about
100
and about 130 wire strands, or between about 110 and about 120 wire strands.
Preferably, litz wires of the inductor coils have about 115 wire strands.
The litz wires may comprise at least four bundles of wire strands. Preferably,
the litz wires comprise five bundles. As briefly mentioned above, each bundle
comprises a plurality of wire strands and the wire strands in each bundle are
twisted
together. The bundles of wires can be twisted/woven together in a similar way.
The
wire strands in all of the bundles add up to the total number of wire strands
in the litz
wire. There may be the same number of wire strands in each bundle. When the
wire
strands are bundled together in the litz wire, each wire may spend a more
equal amount
of time at the outside of the bundle.
Each of the wire strands within the litz wires have a diameter. For example,
the
wire strands may have a diameter of between about 0.05mm and about 0.2mm. In
some
examples, the diameter is between 34 AWG (0.16mm) and 40 AWG (0.0799mm),
where AWG is the American Wire Gauge. In another example, the wire strands
have a
diameter of between 36 AWG (0.127mm) and 39 AWG (0.0897mm). In another
example, the wire strands have a diameter of between 37 AWG (0.113mm) and 38
AWG (0.101mm).
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Preferably, the wire strands have a diameter of 38 AWG (0.101mm), such as
about 0.1mm. It has been found that a litz wire with the above specified
number of wire
strands and these dimensions provide a good balance between effective heating
and
ensuring that the aerosol provision device is compact and lightweight.
The litz wires may have a length of between about 300mm and about 450mm.
For example, a first litz wire of the first inductor coil may have a length
between about
300mm and about 350mm, such as between about 310mm and about 320mm. A second
litz wire forming the second inductor coil may have a length of between about
350mm
and about 450mm, such as between about 390mm and about 410mm. The length of
the
litz wire is the length when the inductor coil is unravelled. In a particular
arrangement,
the first litz wire has a length of about 315mm, and the second litz wire has
a length of
about 400mm. It has been found that these lengths are suitable for providing
effective
heating of the susceptor.
The inductor coils may comprise a litz wire wound (helically) with a
particular
pitch. The pitch is the length of the inductor coil (measured along the
longitudinal axis
of the device/susceptor) over one complete winding. A shorter pitch can induce
a
stronger magnetic field. Conversely, a longer pitch can induce a weaker
magnetic field.
In one arrangement, a first pitch of the first inductor coil is between about
2mm
and about 3mm, and a second pitch of the second inductor coil is between about
2mm
and about 3mm. For example, the first pitch or second pitches may be between
about
2.5mm and about 3mm. In some examples a difference between the first pitch and
the
second pitch is less than about 0.1mm. For example, the first pitch may be
about 2.8mm
and the second pitch may be about 2.9mm. For example, the first pitch may be
about
2.81mm and the second pitch may be about 2.88mm.
The inductor coils may comprise gaps between successive turns and each gap
may have a length of between about 1.4mm and 1.6mm, such as between about
1.5mm
and about 1.6mm. Preferably the gaps are about 1.5mm or 1.6mm. In some
examples
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the gaps between successive turns is slightly different for each inductor
coil. For
example, gaps between successive turns in the first inductor coil may differ
from gaps
between successive turns in the second inductor coil by less than about 0.1mm.
For
example, gaps between successive turns in the first inductor coil may be about
1.51mm
and gaps between successive turns in the second inductor coil may be about
1.58mm.
The first and second inductor coils may have a mass between about lg and about
2.5g. In a particular arrangement, the first inductor coil has a mass of
between about
1.3g and 1.6g, such as 1.4g and the second inductor coil has a mass of between
about
2g and about 2.2g, such as 2.1g.
As mentioned, the litz wire can have a circular cross section. The litz wire
may
have a diameter of between about lmm and about 1.5mm or between about 1.2mm
and
about 1.4mm. Preferably the litz wire has a diameter of about 1.3mm.
In some examples, in use, the inductor coil is configured to heat the
susceptor
to a temperature of between about 240 C and about 300 C, such as between
about
250 C and about 280 C.
The first and/or second inductor coils may be positioned away from an outer
surface of the susceptor by a distance of between about 3mm and about 4mm.
Accordingly, an inner surface of the inductor coils and the outer surface of
the susceptor
may be spaced apart by this distance. The distance may be a radial distance.
It has been
found that distances within this range represent a good balance between the
susceptor
being radially close to the inductor coils to allow efficient heating and
being radially
distant for improved insulation of the induction coils and insulating member.
In another example, the first and/or second inductor coils may be positioned
away from the outer surface of the susceptor by a distance of greater than
about 2.5
mm.
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In another example, the first and/or second inductor coils may be positioned
away from an outer surface of the susceptor by a distance of between about 3mm
and
about 3.5mm. In a further example, the first and/or second inductor coils may
be
positioned away from an outer surface of the susceptor by a distance of
between about
5 3mm and about 3.25mm, for example preferably by about 3.25mm. In another
example,
the first and/or second inductor coils may be positioned away from an outer
surface of
the susceptor by a distance greater than about 3.2mm. In a further example the
first
and/or second inductor coils may be positioned away from an outer surface of
the
susceptor by a distance of less than about 3.5mm, or by less than about 3.3mm.
It has
10 been found that these distances provide a balance between the susceptor
being radially
close to the inductor coils to allow efficient heating and being radially
distant for
improved insulation of the induction coils and insulating member.
In one example, the inner diameter of the first and/or second inductor coils
is
15 about 10-14mm, and the outer diameter is about 12-16mm. In a particular
example, the
inner diameter of the first and/or second inductor coils is about 12-13mm, and
the outer
diameter is about 14-15mm. Preferably the inner diameter of the first and/or
second
inductor coils is about 12mm, and the outer diameter is about 14.6mm. The
inner
diameter of a helical inductor coil is any straight-line segment that passes
through the
20 center of the inductor coil (as viewed in cross section) and whose
endpoints lie on the
inner perimeter of the coil. The outer diameter of a helical inductor coil is
any straight-
line segment that passes through the center of the inductor coil (as viewed in
cross
section) and whose endpoints lie on the outer perimeter of the coil. These
dimensions
can provide effective heating of the susceptor arrangement while retaining a
compact
25 outer size.
The device, coils or heater component described in relation to the sixth
aspect
may comprise any or all of the dimensions or features described in relation to
any of
the other aspects described.
A seventh aspect of the present disclosure defines first and second inductor
coils
which are configured to generate a varying magnetic field for penetrating and
heating
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a susceptor. The susceptor may define an axis, such as a longitudinal axis,
and the first
inductor coil has a first number of turns around the longitudinal axis, and
the second
inductor coil has a second number of turns around the axis. The first and
second
inductor coils may therefore be helical. A turn is one complete rotation about
the
susceptor/axis.
It has been found that when the ratio of the second number of turns to the
first
number of turns is between about 1.1 and about 1.8 the inductor coils provide
a heating
profile that is tailored for different portions of the susceptor and aerosol
generating
material. Thus, in this aspect, the second inductor coil has a greater number
of turns
than the first inductor coil.
In one example, the first inductor coil has fewer turns because the first
inductor
coil has a length that is shorter than the length of the second inductor coil.
The length
of the inductor coil is the length measured along the axis defined by the
susceptor. When
the first inductor coil has fewer turns and a shorter length that the second
inductor coil,
the first inductor coil can provide fast initial heating of a smaller area of
aerosol
generating material. However, if the first number of turns is much less than
the second
number of turns, the volume of aerosol generating material heated via each
inductor
coil is too different. This may negatively impact the experience of the user,
for example,
the user may notice a difference in temperature, volume and concentration of
aerosol
released when the second inductor coil begins to operate. Having the ratio
between
about 1.1 and about 1.8 provides a good balance between these considerations.
Alternatively, the first inductor coil may have fewer turns so that the
magnetic
field generated by the first inductor coil is weaker than the magnetic field
generated by
the second inductor coil. This may be beneficial if the type/density of
aerosol generating
material is not constant along its length. For example, there may be two types
of aerosol
generating material which are to be heated to different temperatures. However,
if the
first number of turns is much less than the second number of turns, the
transition
between heating each region may be too noticeable. Having the ratio between
about 1.1
and about 1.8 provides a good balance between these considerations.
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The first number of turns may be between about 5 and about 7, such as between
about 6 and 7. In a particular example the first number of turns is about
6.75. The second
number of turns may be between about 8 and about 9. In a particular example
the second
number of turns is about 8.75. Wire forming the inductor coils may have a
circular cross
section, for example. It has been found that a circular cross section wire
with this
number of turns for each inductor coil provides effective heating of the
susceptor.
Inductor coils with these number of turns provide a good balance between
providing an
effective magnetic field while providing inductor coils that are relatively
lightweight
and inexpensive.
The first number of turns may be between about 5 and about 7, such as between
about 5 and 6. In a particular example the first number of turns is about
5.75. The second
number of turns may be between about 8 and about 9. In a particular example
the second
number of turns is about 8.75. Wire forming the inductor coils may have a
rectangular
cross section, for example. It has been found that a rectangular cross section
wire with
this number of turns for each inductor coil provides effective heating of the
susceptor.
Inductor coils with these number of turns provide a good balance between
providing an
effective magnetic field while providing inductor coils that are relatively
lightweight
and inexpensive.
Preferably, the ratio of the second number of turns to the first number of
turns
is between about 1.1 and about 1.5, or between about 1.2 and about 1.4, such
as between
about 1.2 and about 1.3. Still more preferably, the ratio may be between about
1.29 and
about 1.3.
In another example, the first number of turns may be between about 5 and about
6. In a particular example the first number of turns is about 5.75. The second
number
of turns may be between about 6 and about 7. In a particular example the
second number
of turns is about 6.75.
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In some examples, the first inductor coil is adjacent the second inductor coil
in
a direction along the longitudinal axis of the susceptor. Thus, the first and
second
inductor coils do not overlap.
In some examples, the first and second inductor coils have substantially the
same "turn density", i.e. substantially the same number of turns per unit
length of the
inductor coil. The first inductor coil may have a first length along the
longitudinal axis,
and a first turn density, and the second inductor coil may have a second
length along
the longitudinal axis and a second turn density. The turn density is the
number of turns
divided by the length of the inductor coil.
In one example the absolute difference between the first turn density and the
second turn density is less than about 0.1mm-1, or less than about 0.05mm-1,
or less than
about 0.01mm-1, or less than about 0.005mm-1. In another example, the
percentage
difference between the first turn density and the second turn density may be
less than
about 15%, or less than about 10%, or less than about 5% or less than about 3%
or less
than about 1%. Thus, when the first and second inductor coils have a similar,
or
substantially the same turn density but a different number of turns, the
susceptor can be
heated more evenly along its full length while controlling the volume of
aerosol
generating material that is heated.
The first and second turn densities may be between about 0.2mm-1 and about
0.5mm-1. In some examples, the first and second turn densities are between
about
0.2mm-1 and about 0.4mm-1, or between about 0.3mm-1 and about 0.4mm-1.
Preferably
the first and second turn densities are between about 0.3mm-1 and about 0.35mm-
1, such
as between about 0.32mm-1 and about 0.34mm-1.
In certain examples, the first inductor coil may have a first length along the
axis
and the second inductor coil may have a second length along the axis, wherein
the first
length is between about 14mm and about 23mm, such as between about 14mm and
about 21mm, and the second length is between about 23mm and about 30mm, such
as
between about 25mm and about 30 mm. Preferably, the first length is between
about
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18mm and about 21mm. In a particular example, the first length is about 20mm
( 1mm). In certain examples, the second inductor coil may have a second length
along
the axis that is between about 25mm and about 30mm. Preferably, the second
length is
between about 25mm and about 28mm. In a particular example, the second length
is
about 26mm ( 1mm). In another example, the first length is about 19mm ( 2mm)
and
the second length is about 25mm ( 2mm).
In certain examples the first length may be greater than the second length by
at
least 5mm.
In another example, the first length (of the first coil) may be between about
lOmm and about 21mm, and the second length (of the second coil) may be between
about 18mm and about 30 mm. In one example, the first length may be about
17.9mm
( 1mm) and the second length may be about 20mm ( 1mm). In another example, the
.. first length may be about lOmm ( 1mm) and the second length may be about
21mm
( 1mm). In another example, the first length may be about 14mm ( 1mm) and the
second length may be about 20mm ( 1mm).
In a preferred arrangement, in use, the aerosol is drawn along a flow path of
the
device towards a proximal end of the device, and the first inductor coil is
arranged
closer to the proximal end of the device than the second inductor coil. Thus,
the inductor
coil with fewer turns may be arranged closer to the mouth end of the device.
This means
that the first inductor coil, with fewer turns, can be energised/activated
initially, which
allows fast initial heating of the aerosol generating material arranged
closest to the
mouth of the user. The second inductor coil, with more turns, can be energised
later
during the heating session. In a preferred arrangement, the first inductor
coil has a first
length along the axis and the second inductor coil has a second length along
the axis,
and wherein the first length is shorter than the second length. Thus, the
first inductor
coil has a shorter length and fewer turns than the second inductor coil. In
such an
arrangement, the end of the susceptor which is closest to the proximal end of
the device
is surrounded by the first, shorter inductor coil. Once aerosol generating
material is
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received within the device, aerosol generating material that is arranged
towards the
proximal end of the device is heated as a result of the first, shorter
inductor coil.
By having a shorter inductor coil with fewer turns arranged closer to the
5 proximal end of the aerosol generating material (which is heated first),
a smaller volume
of aerosol generating material is heated. This reduces the volume of aerosol
that is
produced than would have been produced had a larger volume of material been
heated.
This aerosol is mixed with a volume of ambient/cooler air in the device, and
the
temperature of the aerosol is lowered, thereby avoiding/reducing hot puff.
In some examples, the litz wires of the inductor coils have between about 50
and about 150 wire strands. It has been found that an inductor coil formed
with litz wire
having the above-mentioned turn density and this many wire strands is
particularly
suitable for heating a susceptor used in an aerosol provision device. For
example, the
strength of the magnetic field induced by the inductor coil is well suited to
heat a
susceptor arranged in proximity to the inductor coil.
In another example, the litz wires of the inductor coils have between about
100
and about 130 wire strands, or between about 110 and about 120 wire strands.
Preferably, litz wires of the inductor coils have about 115 wire strands.
The litz wires may comprise at least four bundles of wire strands. Preferably,
the litz wires comprise five bundles. As briefly mentioned above, each bundle
comprises a plurality of wire strands and the wire strands in each bundle are
twisted
together. The bundles of wires can be twisted/woven together in a similar way.
The
wire strands in all of the bundles add up to the total number of wire strands
in the litz
wire. There may be the same number of wire strands in each bundle. When the
wire
strands are bundled together in the litz wire, each wire may spend a more
equal amount
of time at the outside of the bundle.
Each of the wire strands within the litz wires have a diameter. For example,
the
wire strands may have a diameter of between about 0.05mm and about 0.2mm. In
some
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examples, the diameter is between 34 AWG (0.16mm) and 40 AWG (0.0799mm),
where AWG is the American Wire Gauge. In another example, the wire strands
have a
diameter of between 36 AWG (0.127mm) and 39 AWG (0.0897mm). In another
example, the wire strands have a diameter of between 37 AWG (0.113mm) and 38
AWG (0.101mm).
Preferably, the wire strands have a diameter of 38 AWG (0.101mm), such as
about 0.1mm. It has been found that a litz wire with the above specified
number of wire
strands and these dimensions provide a good balance between effective heating
and
ensuring that the aerosol provision device is compact and lightweight.
The litz wires may have a length of between about 300mm and about 450mm.
For example, a first litz wire of the first inductor coil may have a length
between about
300mm and about 350mm, such as between about 310mm and about 320mm. A second
litz wire forming the second inductor coil may have a length of between about
350mm
and about 450mm, such as between about 390mm and about 410mm. The length of
the
litz wire is the length when the inductor coil is unravelled. In a particular
arrangement,
the first litz wire has a length of about 315mm, and the second litz wire has
a length of
about 400mm. It has been found that these lengths are suitable for providing
effective
heating of the susceptor.
The inductor coils may comprise a litz wire wound (helically) with a
particular
pitch. The pitch is the length of the inductor coil (measured along the
longitudinal axis
of the device/susceptor) over one complete winding. A shorter pitch can induce
a
stronger magnetic field. Conversely, a longer pitch can induce a weaker
magnetic field.
In one arrangement, a first pitch of the first inductor coil is between about
2mm
and about 3mm, and a second pitch of the second inductor coil is between about
2mm
and about 3mm. For example, the first pitch or second pitches may be between
about
2.5mm and about 3mm. In some examples a difference between the first pitch and
the
second pitch is less than about 0.1mm. For example, the first pitch may be
about 2.8mm
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and the second pitch may be about 2.9mm. For example, the first pitch may be
about
2.81mm and the second pitch may be about 2.88mm.
The inductor coils may comprise gaps between successive turns and each gap
may have a length of between about 1.4mm and 1.6mm, such as between about
1.5mm
and about 1.6mm. Preferably the gaps are about 1.5mm or 1.6mm. In some
examples
the gaps between successive turns is slightly different for each inductor
coil. For
example, gaps between successive turns in the first inductor coil may differ
from gaps
between successive turns in the second inductor coil by less than about 0.1mm.
For
example, gaps between successive turns in the first inductor coil may be about
1.51mm
and gaps between successive turns in the second inductor coil may be about
1.58mm.
The gap length is measured in a direction parallel to the longitudinal axis of
the
device/susceptor/inductor coil. A gap is a portion where no wire of the coil
is present
(i.e. there is a space between successive turns).
The first and second inductor coils may have a mass between about lg and about
2.5g. In a particular arrangement, the first inductor coil has a mass of
between about
1.3g and 1.6g, such as 1.4g and the second inductor coil has a mass of between
about
2g and about 2.2g, such as 2.1g.
As mentioned, the litz wire can have a circular cross section. The litz wire
may
alternatively have a rectangular cross section. The rectangle may have two
short sides
and two long sides, where the dimensions of the sides of the rectangle define
the area
of the rectangular cross section. Other examples may have a generally square
cross
section, with four substantially equal sides. The cross-sectional area may be
between
about 1.5mm2 and about 3mm2. In a preferred example, the cross-sectional area
is
between about 2mm2 and about 3mm2, or between about 2.2mm2 and about 2.6mm2.
Preferably the cross-sectional area is between about 2.4mm2 and about 2.5mm2.
In examples having a rectangular cross section with two short and two long
sides, the short sides may have a dimension of between about 0.9mm and about
1.4mm,
and the long sides may have a dimension of between about 1.9mm and about
2.4mm.
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Alternatively, the short sides may have a dimension of between about lmm and
about
1.2mm, and the long sides may have a dimension of between about 2.1mm and
about
2.3mm. Preferably the short sides have a dimension of about 1.1mm ( 0.1mm) and
the
long sides have a dimension of about 2.2mm ( 0.1mm). In such an example, the
cross-
sectional area is about 2.42mm2.
The first and/or second inductor coils may be positioned away from an outer
surface of the susceptor by a distance of between about 3mm and about 4mm.
Accordingly, an inner surface of the inductor coils and the outer surface of
the susceptor
may be spaced apart by this distance. The distance may be a radial distance.
It has been
found that distances within this range represent a good balance between the
susceptor
being radially close to the inductor coils to allow efficient heating and
being radially
distant for improved insulation of the induction coils and insulating member.
In another example, the first and/or second inductor coils may be positioned
away from the outer surface of the susceptor by a distance of greater than
about 2.5
mm.
In another example, the first and/or second inductor coils may be positioned
away from an outer surface of the susceptor by a distance of between about 3mm
and
about 3.5mm. In a further example, the first and/or second inductor coils may
be
positioned away from an outer surface of the susceptor by a distance of
between about
3mm and about 3.25mm, for example preferably by about 3.25mm. In another
example,
the first and/or second inductor coils may be positioned away from an outer
surface of
the susceptor by a distance greater than about 3.2mm. In a further example the
first
and/or second inductor coils may be positioned away from an outer surface of
the
susceptor by a distance of less than about 3.5mm, or by less than about 3.3mm.
It has
been found that these distances provide a balance between the susceptor being
radially
close to the inductor coils to allow efficient heating and being radially
distant for
improved insulation of the induction coils and insulating member.
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In a particular example, the aerosol provision device comprises the susceptor.
In other examples, an article comprising aerosol generating material comprises
the
su sceptor.
In one example, the inner diameter of the first and/or second inductor coils
is
about 10-14mm, and the outer diameter is about 12-16mm. In a particular
example, the
inner diameter of the first and/or second inductor coils is about 12-13mm, and
the outer
diameter is about 14-15mm. Preferably the inner diameter of the first and/or
second
inductor coils is about 12mm, and the outer diameter is about 14.6mm. The
inner
diameter of a helical inductor coil is any straight-line segment that passes
through the
center of the inductor coil (as viewed in cross section) and whose endpoints
lie on the
inner perimeter of the coil. The outer diameter of a helical inductor coil is
any straight-
line segment that passes through the center of the inductor coil (as viewed in
cross
section) and whose endpoints lie on the outer perimeter of the coil. These
dimensions
.. can provide effective heating of the susceptor arrangement while retaining
a compact
outer size.
The susceptor may be hollow and/or substantially tubular to allow the aerosol
generating material to be received within the susceptor, such that the
susceptor
surrounds the aerosol generating material.
In some examples, the susceptor comprises one or more features to prevent heat
bleed between two heating zones on the susceptor. A zone is defined as a
region/section
of the susceptor that is surrounded by an inductor coil. For example, if the
device
comprises first and second inductor coils, the susceptor comprises first and
second
zones. The susceptor may comprise holes through the susceptor between each
zone
which can help reduce heat bleed between adjacent zones. Alternatively, the
susceptor
may comprise notches in the outer surface of the susceptor. Alternatively, the
susceptor
may have thinner walls at the boundary between adjacent zones. In another
example,
the susceptor may "bulge" outwards at the positions between adjacent zones to
increase
the conductive path of the susceptor. The bulging sections may also have a
wall that is
thinner than the walls of the adjacent zones.
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In one example, ends of the susceptor can collect heat from an adjacent
heating
zone. For example, the end portion may have a greater thermal mass than an
adjacent
portion. This can act as a heat sink.
5
The device, coils or heater component described in relation to the seventh
aspect
may comprise any or all of the dimensions or features described in relation to
any of
the other aspects described.
10
Figure 1 shows an example of an aerosol provision device 100 for generating
aerosol from an aerosol generating medium/material. In broad outline, the
device 100
may be used to heat a replaceable article 110 comprising the aerosol
generating
medium, to generate an aerosol or other inhalable medium which is inhaled by a
user
of the device 100.
The device 100 comprises a housing 102 (in the form of an outer cover) which
surrounds and houses various components of the device 100. The device 100 has
an
opening 104 in one end, through which the article 110 may be inserted for
heating by a
heating assembly. In use, the article 110 may be fully or partially inserted
into the
heating assembly where it may be heated by one or more components of the
heater
assembly.
The device 100 of this example comprises a first end member 106 which
comprises a lid/cap 108 which is moveable relative to the first end member 106
to close
the opening 104 when no article 110 is in place. In Figure 1, the lid 108 is
shown in an
open configuration, however the lid 108 may move into a closed configuration.
For
example, a user may cause the lid 108 to slide in the direction of arrow "A".
The device 100 may also include a user-operable control element 112, such as
a button or switch, which operates the device 100 when pressed. For example, a
user
may turn on the device 100 by operating the switch 112.
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The device 100 may also comprise an electrical component, such as a
socket/port 114, which can receive a cable to charge a battery of the device
100. For
example, the socket 114 may be a charging port, such as a USB charging port.
Figure 2 depicts the device 100 of Figure 1 with the outer cover 102 removed
and without an article 110 present. The device 100 defines a longitudinal axis
134.
As shown in Figure 2, the first end member 106 is arranged at one end of the
device 100 and a second end member 116 is arranged at an opposite end of the
device
100. The first and second end members 106, 116 together at least partially
define end
surfaces of the device 100. For example, the bottom surface of the second end
member
116 at least partially defines a bottom surface of the device 100. Edges of
the outer
cover 102 may also define a portion of the end surfaces. In this example, the
lid 108
also defines a portion of a top surface of the device 100.
The end of the device closest to the opening 104 may be known as the proximal
end (or mouth end) of the device 100 because, in use, it is closest to the
mouth of the
user. In use, a user inserts an article 110 into the opening 104, operates the
user control
112 to begin heating the aerosol generating material and draws on the aerosol
generated
in the device. This causes the aerosol to flow through the device 100 along a
flow path
towards the proximal end of the device 100.
The other end of the device furthest away from the opening 104 may be known
as the distal end of the device 100 because, in use, it is the end furthest
away from the
mouth of the user. As a user draws on the aerosol generated in the device, the
aerosol
flows away from the distal end of the device 100.
The device 100 further comprises a power source 118. The power source 118
may be, for example, a battery, such as a rechargeable battery or a non-
rechargeable
battery. Examples of suitable batteries include, for example, a lithium
battery (such as
a lithium-ion battery), a nickel battery (such as a nickel¨cadmium battery),
and an
alkaline battery. The battery is electrically coupled to the heating assembly
to supply
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electrical power when required and under control of a controller (not shown)
to heat the
aerosol generating material. In this example, the battery is connected to a
central
support 120 which holds the battery 118 in place.
The device further comprises at least one electronics module 122. The
electronics module 122 may comprise, for example, a printed circuit board
(PCB). The
PCB 122 may support at least one controller, such as a processor, and memory.
The
PCB 122 may also comprise one or more electrical tracks to electrically
connect
together various electronic components of the device 100. For example, the
battery
terminals may be electrically connected to the PCB 122 so that power can be
distributed
throughout the device 100. The socket 114 may also be electrically coupled to
the
battery via the electrical tracks.
In the example device 100, the heating assembly is an inductive heating
assembly and comprises various components to heat the aerosol generating
material of
the article 110 via an inductive heating process. Induction heating is a
process of heating
an electrically conducting object (such as a susceptor) by electromagnetic
induction.
An induction heating assembly may comprise an inductive element, for example,
one
or more inductor coils, and a device for passing a varying electric current,
such as an
alternating electric current, through the inductive element. The varying
electric current
in the inductive element produces a varying magnetic field. The varying
magnetic field
penetrates a susceptor suitably positioned with respect to the inductive
element, and
generates eddy currents inside the susceptor. The susceptor has electrical
resistance to
the eddy currents, and hence the flow of the eddy currents against this
resistance causes
the susceptor to be heated by Joule heating. In cases where the susceptor
comprises
ferromagnetic material such as iron, nickel or cobalt, heat may also be
generated by
magnetic hysteresis losses in the susceptor, i.e. by the varying orientation
of magnetic
dipoles in the magnetic material as a result of their alignment with the
varying magnetic
field. In inductive heating, as compared to heating by conduction for example,
heat is
generated inside the susceptor, allowing for rapid heating. Further, there
need not be
any physical contact between the inductive heater and the susceptor, allowing
for
enhanced freedom in construction and application.
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The induction heating assembly of the example device 100 comprises a
susceptor arrangement 132 (herein referred to as "a susceptor"), a first
inductor coil 124
and a second inductor coil 126. The first and second inductor coils 124, 126
are made
from an electrically conducting material. In this example, the first and
second inductor
coils 124, 126 are made from Litz wire/cable which is wound in a helical
fashion to
provide helical inductor coils 124, 126. Litz wire comprises a plurality of
individual
wires which are individually insulated and are twisted together to form a
single wire.
Litz wires are designed to reduce the skin effect losses in a conductor. In
the example
device 100, the first and second inductor coils 124, 126 are made from copper
Litz wire
which has a rectangular cross section. In other examples the Litz wire can
have other
shape cross sections, such as circular.
The first inductor coil 124 is configured to generate a first varying magnetic
field for heating a first section of the susceptor 132 and the second inductor
coil 126 is
configured to generate a second varying magnetic field for heating a second
section of
the susceptor 132. In this example, the first inductor coil 124 is adjacent to
the second
inductor coil 126 in a direction along the longitudinal axis 134 of the device
100 (that
is, the first and second inductor coils 124, 126 to not overlap). The
susceptor
arrangement 132 may comprise a single susceptor, or two or more separate
susceptors.
Ends 130 of the first and second inductor coils 124, 126 can be connected to
the PCB
122.
It will be appreciated that the first and second inductor coils 124, 126, in
some
examples, may have at least one characteristic different from each other. For
example,
the first inductor coil 124 may have at least one characteristic different
from the second
inductor coil 126. More specifically, in one example, the first inductor coil
124 may
have a different value of inductance than the second inductor coil 126. In
Figure 2, the
first and second inductor coils 124, 126 are of different lengths such that
the first
inductor coil 124 is wound over a smaller section of the susceptor 132 than
the second
inductor coil 126. Thus, the first inductor coil 124 may comprise a different
number of
turns than the second inductor coil 126 (assuming that the spacing between
individual
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turns is substantially the same). In yet another example, the first inductor
coil 124 may
be made from a different material to the second inductor coil 126. In some
examples,
the first and second inductor coils 124, 126 may be substantially identical.
In this example, the first inductor coil 124 and the second inductor coil 126
are
wound in opposite directions. This can be useful when the inductor coils are
active at
different times. For example, initially, the first inductor coil 124 may be
operating to
heat a first section/portion of the article 110, and at a later time, the
second inductor
coil 126 may be operating to heat a second section/portion of the article 110.
Winding
the coils in opposite directions helps reduce the current induced in the
inactive coil
when used in conjunction with a particular type of control circuit. In Figure
2, the first
inductor coil 124 is a right-hand helix and the second inductor coil 126 is a
left-hand
helix. However, in another embodiment, the inductor coils 124, 126 may be
wound in
the same direction, or the first inductor coil 124 may be a left-hand helix
and the second
inductor coil 126 may be a right-hand helix.
The susceptor 132 of this example is hollow and therefore defines a receptacle
within which aerosol generating material is received. For example, the article
110 can
be inserted into the susceptor 132. In this example the susceptor 132 is
tubular, with a
circular cross section.
The susceptor 132 may be made from one or more materials. Preferably the
susceptor 132 comprises carbon steel having a coating of Nickel or Cobalt.
In some examples, the susceptor 132 may comprise at least two materials
capable of being heated at two different frequencies for selective
aerosolization of the
at least two materials. For example, a first section of the susceptor 132
(which is heated
by the first inductor coil 124) may comprise a first material, and a second
section of the
susceptor 132 which is heated by the second inductor coil 126 may comprise a
second,
different material. In another example, the first section may comprise first
and second
materials, where the first and second materials can be heated differently
based upon
operation of the first inductor coil 124. The first and second materials may
be adjacent
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along an axis defined by the susceptor 132, or may form different layers
within the
susceptor 132. Similarly, the second section may comprise third and fourth
materials,
where the third and fourth materials can be heated differently based upon
operation of
the second inductor coil 126. The third and fourth materials may be adjacent
along an
5 axis
defined by the susceptor 132, or may form different layers within the
susceptor
132. Third material may the same as the first material, and the fourth
material may be
the same as the second material, for example. Alternatively, each of the
materials may
be different. The susceptor may comprise carbon steel or aluminium for
example.
10 The
device 100 of Figure 2 further comprises an insulating member 128 which
may be generally tubular and at least partially surround the susceptor 132.
The
insulating member 128 may be constructed from any insulating material, such as
plastic
for example. In this particular example, the insulating member is constructed
from
polyether ether ketone (PEEK). The insulating member 128 may help insulate the
15 various
components of the device 100 from the heat generated in the susceptor 132.
The insulating member 128 can also fully or partially support the first and
second inductor coils 124, 126. For example, as shown in Figure 2, the first
and second
inductor coils 124, 126 are positioned around the insulating member 128 and
are in
20 contact
with a radially outward surface of the insulating member 128. In some examples
the insulating member 128 does not abut the first and second inductor coils
124, 126.
For example, a small gap may be present between the outer surface of the
insulating
member 128 and the inner surface of the first and second inductor coils 124,
126.
25 In a
specific example, the susceptor 132, the insulating member 128, and the
first and second inductor coils 124, 126 are coaxial around a central
longitudinal axis
of the susceptor 132.
Figure 3 shows a side view of device 100 in partial cross-section. The outer
30 cover
102 is present in this example. The rectangular cross-sectional shape of the
first
and second inductor coils 124, 126 is more clearly visible.
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The device 100 further comprises a support 136 which engages one end of the
susceptor 132 to hold the susceptor 132 in place. The support 136 is connected
to the
second end member 116.
The device may also comprise a second printed circuit board 138 associated
within the control element 112.
The device 100 further comprises a second lid/cap 140 and a spring 142,
arranged towards the distal end of the device 100. The spring 142 allows the
second lid
140 to be opened, to provide access to the susceptor 132. A user may open the
second
lid 140 to clean the susceptor 132 and/or the support 136.
The device 100 further comprises an expansion chamber 144 which extends
away from a proximal end of the susceptor 132 towards the opening 104 of the
device.
Located at least partially within the expansion chamber 144 is a retention
clip 146 to
abut and hold the article 110 when received within the device 100. The
expansion
chamber 144 is connected to the end member 106.
Figure 4 is an exploded view of the device 100 of Figure 1, with the outer
cover
102 omitted.
Figure 5A depicts a cross section of a portion of the device 100 of Figure 1.
Figure 5B depicts a close-up of a region of Figure 5A. Figures 5A and 5B show
the
article 110 received within the susceptor 132, where the article 110 is
dimensioned so
that the outer surface of the article 110 abuts the inner surface of the
susceptor 132.
This ensures that the heating is most efficient. The article 110 of this
example comprises
aerosol generating material 110a. The aerosol generating material 110a is
positioned
within the susceptor 132. The article 110 may also comprise other components
such as
a filter, wrapping materials and/or a cooling structure.
Figure 5B shows that the outer surface of the susceptor 132 is spaced apart
from
the inner surface of the inductor coils 124, 126 by a distance 150, measured
in a
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direction perpendicular to a longitudinal axis 158 of the susceptor 132. In
one particular
example, the distance 150 is about 3mm to 4mm, about 3mm to 3.5mm, or about
3.25mm.
Figure 5B further shows that the outer surface of the insulating member 128 is
spaced apart from the inner surface of the inductor coils 124, 126 by a
distance 152,
measured in a direction perpendicular to a longitudinal axis 158 of the
susceptor 132.
In one particular example, the distance 152 is about 0.05mm. In another
example, the
distance 152 is substantially Omm, such that the inductor coils 124, 126 abut
and touch
the insulating member 128.
In one example, the susceptor 132 has a wall thickness 154 of about 0.025mm
to lmm, or about 0.05mm.
In one example, the susceptor 132 has a length of about 40mm to 60mm, about
40mm to 45mm, or about 44.5mm.
In one example, the insulating member 128 has a wall thickness 156 of about
0.25mm to 2mm, 0.25mm to lmm, or about 0.5mm.
As shown in Figure 5A, the litz wire of the first inductor coil 124 is wrapped
around the axis 158 about 5.75 times, and the litz wire of the second inductor
coil 126
is wrapped around the axis 158 about 8.75 times. The litz wires do not form a
whole
number of turns because some ends of the litz wire are bent away from the
surface of
the insulating member 128 before a full turn is completed. The ratio of the
number of
turns in the second inductor coil 126 to the number of turns in the first
inductor coil 124
is therefore about 1.5.
Figure 6 depicts the heating assembly of the device 100. As briefly mentioned
above, the heating assembly comprises a first inductor coil 124 and a second
inductor
coil 126 arranged adjacent to each other, in the direction along the axis 158
(which is
also parallel to the longitudinal axis 134 of the device 100). In use, the
first inductor
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coil 124 is operated initially. This causes a first section of the susceptor
132 to heat up
(i.e. the section of the susceptor 132 surrounded by the first inductor coil
124), which
in turn heats a first portion of the aerosol generating material. At a later
time, the first
inductor coil 124 may be switched off, and the second inductor coil 126 may be
operated. This causes a second section of the susceptor 132 to heat up (i.e.
the section
of the susceptor 132 surrounded by the second inductor coil 126), which in
turn heats a
second portion of the aerosol generating material. The second inductor coil
126 may be
switched on while the first inductor coil 124 is being operated, and the first
inductor
coil 124 may switch off while the second inductor coil 126 continues to
operate.
Alternatively, the first inductor coil 124 may be switched off before the
second inductor
coil 126 is switched on. A controller can control when each inductor coil is
operated/energised. Thus, the inductor coils 124, 126 may be operated
independently
of each other.
In a particular example, both inductor coils 124, 126 are operable in two or
more
different modes. For example, a controller may cause the inductor coils 124,
126 to
operate in a first mode wherein the inductor coils 124, 126 are configured to
heat the
susceptor to a lower temperature than when the inductor coils 124, 126 are
operating in
a second mode.
In the example shown, the susceptor 132 is unitary, such that the first and
second
sections are part of a single susceptor 132. In other examples the first and
second
sections are separate. For example, there may be a gap between the first and
second
sections. The gap may be an air gap, or a gap provided by non-conductive
material.
It has been found that hot puff can be reduced or avoided by making the length
202 of the first inductor coil 124 shorter than the length 204 of the second
inductor coil
126. The length of each inductor coil is measured in a direction parallel to
the axis of
susceptor 158, which is also parallel to the axis of the device 134. Hot puff
can be
reduced because the volume of aerosol generating material being heated by the
first
inductor coil 124 is smaller than the volume of aerosol generating material
being heated
by the second inductor coil 126.
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The first, shorter inductor coil 124 is arranged closer to the mouth end
(proximal
end) of the device 100 than the second inductor coil 126. When the aerosol
generating
material is heated, aerosol is released. When a user inhales, the aerosol is
drawn towards
the mouth end of the device 100, in the direction of arrow 206. The aerosol
exits the
device 100 via the opening/mouthpiece 104, and is inhaled by the user. The
first
inductor coil 124 is arranged closer to the opening 104 than the second
inductor coil
126.
In this example the first and second inductor coils 124, 126 are adjacent and
are
substantially contiguous. Thus, there is no gap 208 between the inductor coils
124, 126
at point P. In other examples however, there may be a gap that is non-zero. In
such a
case, the inductor coils 124, 126 would still be adjacent to each other in a
direction
along the axes 158, 134.
In this example, the first inductor coil 124 has a length 202 of about 20mm,
and
the second inductor coil 126 has a length 204 of about 27mm. A first wire,
which is
helically wound to form the first inductor coil 124, has an unwound length of
about
285mm. A second wire, which is helically wound to form the second inductor
coil 126,
has an unwound length of about 420mm. Although the first and second wires are
depicted with a rectangular cross section, they may have a different shape
cross section,
such as a circular cross section. Figure 10 depicts an example in which a
first inductor
coil 224 and a second inductor coil 226 has a circular cross section.
Figure 7 shows a close up of the first inductor coil 124. Figure 8 shows a
close
up of the second inductor coil 126. In this example, the first inductor coil
124 and the
second inductor coil 126 have different pitches. The first inductor coil 124
has a first
pitch 210, and the second inductor coil has a second pitch 212. The pitch is
the length
of the inductor coil (measured along the longitudinal axis 134 of the device
or along the
longitudinal axis 158 of the susceptor or along an axis of an inductor coil)
over one
complete winding. In another example, each inductor coil may have
substantially the
same pitch.
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Figure 7 depicts the first inductor coil 124 with about 5.75 turns, where one
turn
is one complete rotation around the axis 158. Between each successive turn,
there is a
gap 214. In this example, the length of the gap 214 is about 0.9mm. Similarly,
Figure 8
5 depicts
the second inductor coil 126 with about 8.75 turns. Between each successive
turn, there is a gap 216. In this example, the length of the gap 216 is about
lmm. In this
example, the first inductor coil 124 has a mass of about 1.4g, and the second
inductor
coil 126 has a mass of about 2.1g.
10 In
another example, the first inductor coil 124 has about 6.75 turns. In some
examples, the gaps between successive turns may be the same for each inductor
coil.
Figure 9 depicts a diagrammatic representation of a cross section of another
heating assembly. The heating assembly may be used in the device 100. The
assembly
15
comprises a first inductor coil 224 and a second inductor coil 226 arranged
adjacent to
each other, in the direction along the longitudinal axis 258 of a susceptor
232 (which is
also parallel to the longitudinal axis 134 of the device 100). The susceptor
232 may be
substantially the same as the susceptor 132 described in relation to Figures 1-
8. The
first and second inductor coils 224, 226 are helically wound around an
insulating
20 member
228, which may be substantially the same as the insulating member 128
described in relation to Figures 1-8.
The first and second inductor coils 224, 226 may operate, and be operated, in
substantially the same way as the first and second inductor coils 124, 126
described in
25
relation to the Figures 1-8. In certain examples, the first inductor coil 224
is arranged
closer to the proximal end of the device 100 than the second inductor coil
226. The first
inductor coil 224 is shorter than the second inductor coil 226, as measured in
a direction
parallel to the axes 134, 258.
30 Unlike
the example of Figure 6, in this heating arrangement the first and second
inductor coils 224, 226 are adjacent, but are not contiguous. Thus, there is a
gap between
the inductor coils 224, 226. In other examples however, there may not be a
gap.
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In addition, unlike the example of Figures 6-8, the first and second wires
(which
make up the first and second inductor coils 224, 226 respectively) have a
circular cross
section, however they may be replaced by wires having a different shape cross
section.
Furthermore, in this example, there is no gap 302 between successive turns in
either of the first and second inductor coils 224, 226.
Further still, in this example, the pitch for both the first and second
inductor
coils 224, 226 is substantially the same. For example, it may be between about
2mm
and about 4mm, or be between about 3mm and about 4mm.
Other properties and dimensions of the inductor coils 224, 226 may be the
same,
or different as to those described in relation to Figures 6-8.
Figure 9 depicts the outer perimeter of the first inductor coil 224 being
positioned away from the susceptor 232 by a distance 304. Similarly, the outer
perimeter of the second inductor coil 226 is positioned away from the
susceptor by the
same distance 304. Accordingly, the first and second inductor coils have
substantially
the same external diameter 306. Figure 9 also depicts the internal diameter
308 of the
first and second inductor coils 224, 226 as being substantially the same.
The "outer perimeter" of the inductor coils 224, 226 is the edge of the
inductor
coil that is positioned furthest away from the outer surface 232a of the
susceptor 232,
in a direction perpendicular to the longitudinal axis 258.
In Figures 6-8, the outer perimeter of the first inductor coil 124 is also
positioned
away from the susceptor 132 by substantially the same distance as the outer
perimeter
of the second inductor coil 126.
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In one example, the inner diameter of the first and second inductor coils 124,
224, 224, 226 is about 12mm in length, and the outer diameter is about 14.6mm
in
length.
Figure 10 depicts part of another example heating assembly for use in device
100. In this example, the rectangular cross section litz wires which form the
inductor
coils have been replaced with inductor coils comprising litz wire with a
circular cross
section. Other features of the device are substantially the same. The heating
assembly
comprises a first inductor coil 224 and a second inductor coil 226 arranged
adjacent to
each other, in the direction along an axis 200. In other example, the wires
forming the
first and second inductor coils 224, 226 may have a different shape cross
section, such
as a rectangular cross section.
The axis 200 may be defined by one, or both, of the inductor coils 224, 226
for
example. The axis 200 is parallel to the longitudinal axis 134 of the device
100) and is
parallel to the longitudinal axis of the susceptor 158. Each inductor coil
224, 226
therefore extends around the axis 200. Alternatively, the axis 200 may be
defined by
the insulating member 128 or susceptor 132.
The first and second inductor coils 224, 226 are arranged adjacent to each
other,
in the direction along the axis 200. The inductor coils 224, 226 helically
extend around
the insulating member 128. The susceptor 132 is arranged within the tubular
insulating
member 128.
As mentioned in relation to Figure 6, in use, the first inductor coil 224 is
operated initially. However, in another example, the second inductor coil 226
is
operated initially.
In certain aspects of the present disclosure, the length 202 of the first
inductor
coil 224 is shorter than the length 204 of the second inductor coil 226. The
length of
each inductor coil is measured in a direction parallel to the axis 200 of the
inductor coils
224, 226. In some examples the first, shorter inductor coil 224 is arranged
closer to the
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mouth end (proximal end) of the device 100 than the second inductor coil 226,
however
in other examples, the second longer inductor coil 226 is arranged closer to
the proximal
end of the device 100.
In one example, the first inductor coil 224 has a length 202 of about 15mm,
and
the second inductor coil 226 has a length 204 of about 25mm. The ratio of the
second
length 204 to the first length 202 is therefore about 1.7, such as about 1.67.
In another
example, the first inductor coil 224 has a length 202 of about 15mm, and the
second
inductor coil 226 has a length 204 of about 30mm. The ratio of the second
length 204
to the first length 202 is therefore about 2. In another example, the first
inductor coil
224 has a length 202 of about 20mm, and the second inductor coil 226 has a
length 204
of about 25mm. The ratio of the second length 204 to the first length 202 is
therefore
between about 1.2 and about 1.3, such as about 1.25. In another example, the
first
inductor coil 224 has a length 202 of about 20mm, and the second inductor coil
226 has
a length 204 of about 30mm. The ratio of the second length 204 to the first
length 202
is therefore about 1.5. In another example, the first inductor coil 224 has a
length 202
of about 14mm, and the second inductor coil 226 has a length 204 of about
28mm. The
ratio of the second length 204 to the first length 202 is therefore about 2.
In another
example, the first inductor coil 224 has a length 202 of about 15mm, and the
second
inductor coil 226 has a length 204 of about 45mm. The ratio of the second
length 204
to the first length 202 is therefore about 3.
In a preferred example, the first inductor coil 224 has a length 202 of
between
about 19 and 21mm, such as about 20.3mm, and the second inductor coil 226 has
a
length 204 of between about 26mm and about 28mm, such as about 26.2mm. The
ratio
of the second length 204 to the first length 202 is therefore between about
1.2 and about
1.5, such as about 1.3.
As mentioned, in some examples, the first inductor coil 224 has a length 202
of
about 20mm, such as about 20.3mm and the second inductor coil 226 has a length
204
of about 27mm, such as about 26.6mm.
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As shown in Figure 10, the litz wire of the first inductor coil 224 is wrapped
around the axis 200 about 6.75 times, and the litz wire of the second inductor
coil 226
is wrapped around the axis 200 about 8.75 times. The litz wires do not form a
whole
number of turns because some ends of the litz wire are bent away from the
surface of
the insulating member 128 before a full turn is completed. The ratio of the
number of
turns in the second inductor coil 226 to the number of turns in the first
inductor coil 224
is therefore about 1.3.
For the first inductor coil 224, the turn density (i.e. the ratio of the
number of
turns to the first length 202) is about 0.33mm-1. For the second inductor coil
226 the
turn density (i.e. the ratio of the number of turns to the second length 204)
is about
0.33mm-1. The first and second inductor coils 224, 226 therefore have
substantially the
same turn density, which results in a more even heating of the susceptor 132
and aerosol
generating material 110a.
In other examples, the first inductor coil 224 may have a first length 202
that is
between about 15mm and about 21mm. The turn density may be between about 0.2
mnril and about 0.5mm-1 but is preferably between about 0.25mm-1 and about
0.35mm-
1. The second inductor coil 226 may have a second length 204 that is between
about
25mm and about 30mm. the turn density may be between about 0.2mm-1 and about
0.5mm-1 but is preferably between about 0.25mm-1 and about 0.35mm-1, such as
between about 0.3mm-1 and about 0.35mm-1. Turn densities within these ranges
are
particularly well suited for heating the susceptor 132. In some examples the
turn density
of the first coil differs from the turn density of the second coil by less
than about
0.05mm-1.
These turn densities may also be applicable to litz wires having different
shaped
cross sections, such as a rectangular cross-section.
In one example, the first inductor coil 224 has between about 5 turns and
about
7 turns. In some examples the second inductor coil 226 has between about 8 and
10
turns. In further examples the inductor coils have a different number of turns
to those
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mentioned. In any case, it is preferred that the ratio of the number of turns
in the second
inductor coil 126 to the number of turns in the first inductor coil 124 is
between about
1.1 and about 1.8.
5 In one
example, a first wire, which is helically wound to form the first inductor
coil 224, has an unwound length of about 315mm. A second wire, which is
helically
wound to form the second inductor coil 226, has an unwound length of about
400mm.
In another example, a first wire, which is helically wound to form the first
inductor coil
224, has an unwound length of about 285mm. A second wire, which is helically
wound
10 to form the second inductor coil 226, has an unwound length of about
420mm.
Each inductor coil 224, 226 is formed from litz wire comprising a plurality of
wire strands. For example, there may be between about 50 and about 150 wire
strands
in each litz wire. In the present example, there are about 75 wire strands in
each litz
15 wire.
In some examples, the wire strands are grouped into two or more bundles, where
each bundle comprises a number of wire strands such that the wire strands in
all bundles
add up to the total number of wire strands. In the present example there are 5
bundles
of 15 wire strands.
20 Each of
the wire strands have a diameter. For example, the diameter may be
between about 0.05mm and about 0.2mm. In some examples, the diameter is
between
34 AWG (0.16mm) and 40 AWG (0.0799mm), where AWG is the American Wire
Gauge. In this example, each of the wire strands have a diameter of 38 AWG
(0.101mm). The litz wire may therefore have a radius of between about lmm and
about
25 2mm. In
this example, the litz wire has a radius of between about 1.3mm and about
1.4mm.
Figure 10 shows gaps between successive windings/turns. These gaps may be
between about 0.5mm and about 2mm, for example.
In some examples, each inductor coil 224, 226 has the same pitch, where the
pitch is the length of the inductor coil (measured along the axis 200 of the
inductor coil
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or along the longitudinal axis 158 of the susceptor) over one complete
winding. In other
examples each inductor coil 224, 226 has a different pitch.
In this example, the first inductor coil 224 has a mass of about 1.4g, and the
second inductor coil 226 has a mass of about 2.1g.
In one example the inner diameter of the first and second inductor coils 224,
224, 224, 226 is about 12mm in length, and the outer diameter is about 14.6mm
in
length.
In a particular example, the first, shorter inductor coil 224 is arranged
closer to
the mouth end (proximal end) of the device 100 than the second inductor coil
226. When
the aerosol generating material is heated, aerosol is released. When a user
inhales, the
aerosol is drawn towards the mouth end of the device 100, in the direction of
arrow 206.
The aerosol exits the device 100 via the opening/mouthpiece 104, and is
inhaled by the
user. The first inductor coil 224 is arranged closer to the opening 104 than
the second
inductor coil 226. It has been found that hot puff can be reduced or avoided
by making
the length 202 of the first inductor coil 224 shorter than the length 204 of
the second
inductor coil 226. Hot puff can be reduced because the volume of aerosol
generating
material being heated by the first inductor coil 224 is smaller than the
volume of aerosol
generating material being heated by the second inductor coil 226.
In this example the first and second inductor coils 224, 226 are adjacent and
are
spaced apart by a gap. In other examples, the first and second inductor coils
224, 226
are substantially contiguous. Thus, there is no gap between the inductor coils
224, 226.
The example inductor coils of Figures 7 and 8 may have the same lengths and/or
parameters as those described in Figures 6 and/or 10. Similarly, the inductor
coils of
Figure 6 and/or 10 may have the same lengths and/or parameters as the inductor
coils
of Figures 7 and 8.
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Figure 11 shows a close up of the first inductor coil 224. Figure 12 shows a
close up of the second inductor coil 226. In this example, the first inductor
coil 224 and
the second inductor coil 226 have slightly different pitches. The first
inductor coil 224
has a first pitch 210, and the second inductor coil has a second pitch 212. In
this
example, the first pitch is smaller than the second pitch, more specifically
the first pitch
210 is about 2.81mm, and the second pitch 212 is about 2.88mm. In other
example, the
pitches are the same for each inductor coil, or the second pitch is smaller
than the first
pitch.
Figure 11 depicts the first inductor coil 224 with about 6.75 turns, where one
turn is one complete rotation around the axis 158 or the susceptor 132 or axis
200 of
the inductor coils 224, 226. Between each successive turn, there is a gap 214.
In this
example, the length of the gap 214 is about 1.51mm. Similarly, Figure 12
depicts the
second inductor coil 226 with about 8.75 turns. Between each successive turn,
there is
a gap 216. In this example, the length of the gap 216 is about 1.58mm. The gap
size is
equal to the difference between the pitch and the diameter of the litz wire.
Thus, in this
example, the litz wire has a diameter of about 1.3mm.
In this example, the first inductor coil 224 has a mass of about 1.4g, and the
second inductor coil 226 has a mass of about 2.1g.
Figure 13 is a diagrammatic representation of a cross section through the litz
wire forming either of the first and second inductor coils 224, 226. As shown,
the litz
wire has a circular cross section (the individual wires forming the litz wire
are not
shown for clarity). The litz wire has a diameter 218, which may be between
about lmm
and about 1.5mm. In this example, the diameter is about 1.3mm.
Figure 14 is a diagrammatic representation of a top down view of either of the
inductor coils 224, 226. In this example the inductor coil 224, 226 is
arranged coaxially
with the longitudinal axis 158 of the susceptor 132 (although the susceptor
132 is not
depicted for clarity).
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Figure 14 shows the inductor coil 224, 226 with outer diameter 222 and an
inner
diameter 228. The outer diameter 222 may be between about 12mm and about 16mm
and the inner diameter 228 may be between about lOmm and about 14mm. In this
particular example, the inner diameter 228 is about 12.2mm in length, and the
outer
diameter 222 is about 14.8mm in length.
Figure 15 is another example diagrammatic representation of a cross section of
the heating assembly. Figure 15 depicts the outer perimeter/surface of the
inductor coils
224, 226 being positioned away from the susceptor 232 by a distance 304.
Accordingly,
the first and second inductor coils have substantially the same external
diameter 306.
Figure 15 also depicts the internal diameter 308 of the first and second
inductor coils
224, 226 as being substantially the same.
The "outer perimeter" of the inductor coils 224, 226 is the edge of the
inductor
coil that is positioned furthest away from the outer surface 132a of the
susceptor 132,
in a direction perpendicular to the longitudinal axis 158.
As shown, the inner surfaces of the inductor coils 224, 226 are positioned
away
from the outer surface 132a of the susceptor 132 by a distance 310. The
distance may
be between about 3mm and about 4mm, such as about 3.25mm.
Unlike the example of Figure 9, there are gaps 214, 216 between successive
turns in the first and second inductor coils 224, 226.
In an alternative example, a first length (of a first coil) may be between
about
14mm and about 23mm, and a second length (of a second coil) may be between
about
23mm and about 28mm. More particularly, the first length may be about 19mm (
2mm)
and the second length may be about 25mm ( 2mm). In this alternative example,
the
first coil may have between about 5 and 7 turns, and the second coil may have
between
.. about 4 and 5 turns. For example, the first coil may have about 6.75 turns,
and the
second coil may have about 4.75 turns. The ratio of number of turns of the
longer coil
to the number of turns of the shorter coil is therefore about 1.42. In the
first coil, the
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ratio of the number of turns to the length is about 0.36mm-1. In the second
coil, the ratio
of the number of turns to the length is about 0.2mm-1, such as about 0.19 mm-
1.
In this alternative example, the second coil may have a pitch that varies
across
its length. For example, the second coil may have a first number of turns with
a first
pitch, and a second number of turns with a second pitch, where the second
pitch is
greater than the first pitch. In a particular example, the second coil has
between about
3 and 4 turns with a pitch of between about 2mm and 3mm, and one turn with a
pitch
of between about 18mm and 22mm. In particular, the second coil has 3.75 turns
with a
pitch of 2.81mm and one turn with a pitch of 20mm. The second coil may
therefore
have 4.75 turns in total. The second coil is therefore more tightly wound
towards one
end of the coil. In one example, a first portion of the second coil has the
first number of
turns with the first (smaller) pitch, and a second portion of the second coil
has the
second number of turns with the second (larger) pitch, where the first portion
is closer
to the proximal/mouth end of the device than the second portion.
The above embodiments are to be understood as illustrative examples of the
invention. Further embodiments of the invention are envisaged. It is to be
understood
that any feature described in relation to any one embodiment may be used
alone, or in
combination with other features described, and may also be used in combination
with
one or more features of any other of the embodiments, or any combination of
any other
of the embodiments. Furthermore, equivalents and modifications not described
above
may also be employed without departing from the scope of the invention, which
is
defined in the accompanying claims.
