U.S. patent application number 14/127138 was filed with the patent office on 2014-08-07 for insulating.
This patent application is currently assigned to BRITISH AMERICAN TOBACCO (INVESTMENTS) LIMITED. The applicant listed for this patent is Oleg Abramov, Petr Egoyants, Pavel Fimin, Dmitry Volobuev. Invention is credited to Oleg Abramov, Petr Egoyants, Pavel Fimin, Dmitry Volobuev.
Application Number | 20140216485 14/127138 |
Document ID | / |
Family ID | 47831554 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140216485 |
Kind Code |
A1 |
Egoyants; Petr ; et
al. |
August 7, 2014 |
INSULATING
Abstract
Thermal insulation comprising a boundary comprising a first
boundary section, a second boundary section and a third boundary
section which connects the first and second boundary sections
together; and an internal insulating region inside the boundary and
configured to thermally insulate the first boundary section from
the second boundary section; wherein the third boundary section
follows an indirect path between the first and second boundary
sections. An apparatus configured to volatilize components of
smokable material, comprising the insulation, is also
described.
Inventors: |
Egoyants; Petr; (St.
Petersburg, RU) ; Fimin; Pavel; (St. Petersburg,
RU) ; Volobuev; Dmitry; (St. Petersburg, RU) ;
Abramov; Oleg; (St. Petersburg, RU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Egoyants; Petr
Fimin; Pavel
Volobuev; Dmitry
Abramov; Oleg |
St. Petersburg
St. Petersburg
St. Petersburg
St. Petersburg |
|
RU
RU
RU
RU |
|
|
Assignee: |
BRITISH AMERICAN TOBACCO
(INVESTMENTS) LIMITED
London
GB
|
Family ID: |
47831554 |
Appl. No.: |
14/127138 |
Filed: |
August 24, 2012 |
PCT Filed: |
August 24, 2012 |
PCT NO: |
PCT/EP2012/066485 |
371 Date: |
February 10, 2014 |
Current U.S.
Class: |
131/329 ;
428/174; 428/220 |
Current CPC
Class: |
Y10T 428/24628 20150115;
A24F 47/008 20130101; F16L 59/065 20130101 |
Class at
Publication: |
131/329 ;
428/174; 428/220 |
International
Class: |
A24F 47/00 20060101
A24F047/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2011 |
RU |
2011 136 868 |
Apr 23, 2012 |
GB |
1207054.6 |
Claims
1. Thermal insulation comprising: a boundary comprising a first
boundary section, a second boundary section and a third boundary
section which connects the first and second boundary sections
together; and an internal insulating region inside the boundary and
configured to thermally insulate the first boundary section from
the second boundary section; wherein the third boundary section
follows an indirect path between the first and second boundary
sections.
2. Insulation according to claim 1, wherein the internal insulating
region has a lower pressure than a pressure at the exterior of the
boundary.
3. Insulation according to claim 1 or 2, wherein the first boundary
section is substantially opposite the second boundary section.
4. Insulation according to any preceding claim, wherein the third
boundary section extends between the first boundary section and the
second boundary section at an edge of the insulation.
5. Insulation according to any preceding claim, wherein the third
boundary section extends between an edge of the first boundary
section and an edge of the second boundary section.
6. Insulation according to any preceding claim, wherein a thermal
conductivity of the third boundary section is higher than a thermal
conductivity of the internal insulating region.
7. Insulation according to any preceding claim, wherein the
indirect path comprises a non-straight path.
8. Insulation according to any preceding claim, wherein the
indirect path comprises a winding path comprising a plurality of
bends.
9. Insulation according to claim 8, wherein sequential ones of the
bends alternate in direction.
10. Insulation according to any preceding claim, wherein the
boundary comprises a wall and the boundary sections comprise
sections of the wall.
11. Insulation according to claim 10, wherein the wall comprises a
metallic wall.
12. Insulation according to claim 10 or 11, wherein the wall has a
thickness of at least approximately 100 microns.
13. Insulation according to any of claims 1 to 12, where the
internal insulating region comprises a deep vacuum.
14. Insulation according to claim 13, wherein the vacuum is a hyper
deep vacuum.
15. An apparatus according to any preceding claim, wherein a
pressure in the internal insulating region is of the order
10.sup.-7 Torr.
16. Insulation according to any of claims 1 to 12, wherein a
pressure in the internal insulating region is between approximately
0.1 and approximately 0.001 mbar.
17. An apparatus according to any preceding claim, wherein a
thickness of the insulation is less than approximately 1 mm.
18. An apparatus according to any preceding claim, wherein a
thickness of the insulation is less than approximately 0.1 mm.
19. An apparatus according to any of claims 1 to 16, wherein a
thickness of the insulation is between approximately 1 mm and 0.001
mm.
20. An apparatus comprising a heater configured to heat smokable
material to volatilize at least one component of the smokable
material, and insulation according to any of claims 1 to 18
configured to thermally insulate the apparatus.
21. An apparatus according to claim 20, wherein the first boundary
section is closer to the heater than the second boundary section,
the second boundary section being separated from the heater by the
internal insulating region.
22. An apparatus according to claim 20 or 21, comprising a smokable
material heating chamber located between the heater and the
insulation.
23. An apparatus according to any of claims 20 to 22, wherein the
heater is elongate and extends along a longitudinal axis of a
housing of the apparatus.
24. An apparatus according to any of claims 20 to 23, wherein the
insulation is located co-axially around the heater.
25. An apparatus according to any of claims 20 to 24, wherein the
apparatus is configured to heat the smokable material without
combusting the smokable material.
26. An apparatus according to any of claims 20 to 25, wherein the
third boundary section extends beyond an end of the heater.
Description
FIELD
[0001] The invention relates to insulating.
BACKGROUND
[0002] Smoking articles such as cigarettes and cigars burn tobacco
during use to create tobacco smoke. Attempts have been made to
provide alternatives to these smoking articles by creating products
which release compounds without creating tobacco smoke. Examples of
such products are so-called heat-not-burn products which release
compounds by heating, but not burning, tobacco.
[0003] The invention aims to provide an improved apparatus and
method for heating tobacco, which can be used in a heat-not-burn
device.
SUMMARY
[0004] According to the invention, there is provided thermal
insulation comprising: [0005] a boundary comprising a first
boundary section, a second boundary section and a third boundary
section which connects the first and second boundary sections
together; and [0006] an internal insulating region inside the
boundary and configured to thermally insulate the first boundary
section from the second boundary section; [0007] wherein the third
boundary section follows an indirect path between the first and
second boundary sections.
[0008] The internal insulating region may have a lower pressure
than a pressure at the exterior of the boundary.
[0009] The first boundary section may be substantially opposite the
second boundary section.
[0010] The third boundary section may extend between the first
boundary section and the second boundary section at an edge of the
insulation.
[0011] The third boundary section may extend between an edge of the
first boundary section and an edge of the second boundary
section.
[0012] A thermal conductivity of the third boundary section may be
higher than a thermal conductivity of the internal insulating
region.
[0013] The indirect path may comprise a non-straight path.
[0014] The indirect path may comprise a winding path comprising a
plurality of bends.
[0015] Sequential ones of the bends may alternate in direction.
[0016] The boundary may comprise a wall and the boundary sections
may comprise sections of the wall.
[0017] The wall may comprise a metallic wall.
[0018] Wall sections either side of the internal insulating region
may converge to a sealed gas outlet.
[0019] Said wall sections may converge in an end region of the
insulation.
[0020] A thickness of the insulation may be less than approximately
1 mm.
[0021] A thickness of the insulation may be less than approximately
0.1 mm.
[0022] A thickness of the insulation may be between approximately 1
mm and 0.001 mm.
[0023] The wall may have a thickness of at least approximately 100
microns.
[0024] A pressure in the internal insulating region may be between
approximately 0.1 and approximately 0.001 mbar.
[0025] According to the invention, there may be provided an
apparatus comprising a heater configured to heat smokable material
to volatilize at least one component of the smokable material, and
the insulation recited above configured to thermally insulate the
apparatus.
[0026] The first boundary section may be closer to the heater than
the second boundary section, the second boundary section being
separated from the heater by the internal insulating region.
[0027] The apparatus may comprise a smokable material heating
chamber located between the heater and the insulation.
[0028] The heater may be elongate and may extend along a
longitudinal axis of a housing of the apparatus.
[0029] The insulation may be located co-axially around the
heater.
[0030] The apparatus may be configured to heat the smokable
material without combusting the smokable material.
[0031] The third boundary section may extend beyond an end of the
heater.
[0032] According to an aspect of the invention, there is provided
an apparatus configured to heat smokable material to volatilize at
least one component of the smokable material, comprising an
infra-red heater.
[0033] The infra-red heater may comprise a halogen infra-red
heater.
[0034] For exemplary purposes only, embodiments of the invention
are described below with reference to the accompanying figures in
which:
BRIEF DESCRIPTION OF THE FIGURES
[0035] FIG. 1 is a perspective, partially cut-away illustration of
an apparatus configured to heat smokable material to release
aromatic compounds and/or nicotine from the smokable material;
[0036] FIG. 2 is a perspective, partially cut-away illustration of
an apparatus configured to heat smokable material, in which the
smokable material is provided around an elongate ceramic heater
divided into radial heating sections;
[0037] FIG. 3 is an exploded, partially cut-away view of an
apparatus configured to heat smokable material, in which the
smokable material is provided around an elongate ceramic heater
divided into radial heating sections;
[0038] FIG. 4 is a perspective, partially cut-away illustration of
an apparatus configured to heat smokable material, in which the
smokable material is provided around an elongate infra-red
heater;
[0039] FIG. 5 is an exploded, partially cut-away illustration of an
apparatus configured to heat smokable material, in which the
smokable material is provided around an elongate infra-red
heater;
[0040] FIG. 6 is a schematic illustration of part of an apparatus
configured to heat smokable material, in which the smokable
material is provided around a plurality of longitudinal, elongate
heating sections spaced around a central longitudinal axis;
[0041] FIG. 7 is a perspective illustration of part of an apparatus
configured to heat smokable material, in which the regions of
smokable material are provided between pairs of upstanding heating
plates;
[0042] FIG. 8 is a perspective illustration of the apparatus shown
in FIG. 7, in which an external housing is additionally
illustrated;
[0043] FIG. 9 is an exploded view of part of an apparatus
configured to heat smokable material, in which the regions of
smokable material are provided between pairs of upstanding heating
plates;
[0044] FIG. 10 is a flow diagram showing a method of activating
heating regions and opening and closing heating chamber valves
during puffing;
[0045] FIG. 11 is a schematic illustration of a gaseous flow
through an apparatus configured to heat smokable material;
[0046] FIG. 12 is a graphical illustration of a heating pattern
which can be used to heat smokable material using a heater;
[0047] FIG. 13 is a schematic illustration of a smokable material
compressor configured to compress smokable material during
heating;
[0048] FIG. 14 is a schematic illustration of a smokable material
expander configured to expand smokable material during puffing;
[0049] FIG. 15 is a flow diagram showing a method of compressing
smokable material during heating and expanding the smokable
material for puffing;
[0050] FIG. 16 is a schematic, cross-sectional illustration of a
section of vacuum insulation configured to insulate heated smokable
material from heat loss;
[0051] FIG. 17 is another schematic, cross-sectional illustration
of a section of vacuum insulation configured to insulate heated
smokable material from heat loss;
[0052] FIG. 18 is a schematic, cross-sectional illustration of a
heat resistive thermal bridge which follows an indirect path from a
higher temperature insulation wall to a lower temperature
insulation wall;
[0053] FIG. 19 is a schematic, cross-sectional illustration of a
heat shield and a heat-transparent window which are moveable
relative to a body of smokable material to selectively allow
thermal energy to be transmitted to different sections of the
smokable material through the window;
[0054] FIG. 20 is schematic, cross sectional illustration of part
of an apparatus configured to heat smokable material, in which a
heating chamber is hermetically sealable by check valves;
[0055] FIG. 21 is a schematic, cross sectional illustration of an
apparatus configured to heat smokable material, in which a heater
is located externally of a heating chamber and internally of
thermal insulation; and
[0056] FIG. 22 is a schematic, cross sectional illustration of a
partial section of deep-vacuum insulation configured to thermally
insulate an apparatus configured to heat smokable material.
DETAILED DESCRIPTION
[0057] As used herein, the term `smokable material` includes any
material that provides volatilized components upon heating and
includes any tobacco-containing material and may, for example,
include one or more of tobacco, tobacco derivatives, expanded
tobacco, reconstituted tobacco or tobacco substitutes.
[0058] An apparatus 1 for heating smokable material comprises an
energy source 2, a heater 3 and a heating chamber 4. The energy
source 2 may comprise a battery such as a Li-ion battery, Ni
battery, Alkaline battery and/or the like, and is electrically
coupled to the heater 3 to supply electrical energy to the heater 3
when required. The heating chamber 4 is configured to receive
smokable material 5 so that the smokable material 5 can be heated
in the heating chamber 4. For example, the heating chamber 4 may be
located adjacent to the heater 3 so that thermal energy from the
heater 3 heats the smokable material 5 therein to volatilize
aromatic compounds and nicotine in the smokable material 5 without
burning the smokable material 5. A mouthpiece 6 is provided through
which a user of the apparatus 1 can inhale the volatilized
compounds during use of the apparatus 1. The smokable material 5
may comprise a tobacco blend.
[0059] As shown in FIG. 1, the heater 3 may comprise a
substantially cylindrical, elongate heater 3 and the heating
chamber 4 is located around a circumferential, longitudinal surface
of the heater 3. The heating chamber 4 and smokable material 5
therefore comprise co-axial layers around the heater 3. However, as
will be evident from the discussion below, other shapes and
configurations of the heater 3 and heating chamber 4 can
alternatively be used.
[0060] A housing 7 may contain components of the apparatus 1 such
as the energy source 2 and heater 3. As shown in FIG. 1, the
housing 7 may comprise an approximately cylindrical tube with the
energy source 2 located towards its first end 8 and the heater 3
and heating chamber 4 located towards its opposite, second end 9.
The energy source 2 and heater 3 extend along the longitudinal axis
of the housing 7. For example, as shown in FIG. 1, the energy
source 2 and heater 3 can be aligned along the central longitudinal
axis of the housing 7 in an end-to-end arrangement so that an end
face of the energy source 2 faces an end face of the heater 3. The
length of the housing 7 may be approximately 130 mm, the length of
energy source may be approximately 59 mm, and the length of the
heater 3 and heating region 4 may be approximately 50 mm. The
diameter of the housing 7 may be between approximately 15 mm and
approximately 18 mm. For example, the diameter of the housing's
first end 8 may be 18 mm whilst the diameter of the mouthpiece 6 at
the housing's second end 9 may be 15 mm. The diameter of the heater
3 may be between approximately 2.0 mm and approximately 6.0 mm. The
diameter of the heater 3 may, for example, be between approximately
4.0 mm and approximately 4.5 mm or between approximately 2.0 mm and
approximately 3.0 mm. Heater diameters outside these range may
alternatively be used. The depth of the heating chamber 4 may be
approximately 5 mm and the heating chamber 4 may have an exterior
diameter of approximately 10 mm at its outwardly-facing surface.
The diameter of the energy source 2 may be between approximately
14.0 mm and approximately 15.0 mm, such as 14.6 mm.
[0061] Heat insulation may be provided between the energy source 2
and the heater 3 to prevent direct transfer of heat from one to the
other. The mouthpiece 6 can be located at the second end 9 of the
housing 7, adjacent the heating chamber 4 and smokable material 5.
The housing 7 is suitable for being gripped by a user during use of
the apparatus 1 so that the user can inhale volatilized smokable
material compounds from the mouthpiece 6 of the apparatus 1.
[0062] Referring to FIGS. 2 and 3, the heater 3 may comprise a
ceramics heater 3. The ceramics heater 3 may, for example, comprise
base ceramics of alumina and/or silicon nitride which are laminated
and sintered. Alternatively, referring to FIGS. 4 and 5, the heater
3 may comprise an infra-red (IR) heater 3 such as a halogen-IR lamp
3. The IR heater 3 may have a low mass and therefore its use can
help to reduce the overall mass of the apparatus 1. For example,
the mass of the IR heater may be 20% to 30% less than the mass of a
ceramics heater 3 having an equivalent heating power output. The IR
heater 3 also has low thermal inertia and therefore is able to heat
the smokable material 5 very rapidly in response to an activation
stimulus. The IR heater 3 may be configured to emit IR
electromagnetic radiation of between approximately 700 nm and 4.5
.mu.m in wavelength.
[0063] As indicated above and shown in FIG. 1, the heater 3 may be
located in a central region of the housing 7 and the heating
chamber 4 and smokable material 5 may be located around the
longitudinal surface of the heater 3. In this arrangement, thermal
energy emitted by the heater 3 travels in a radial direction
outwards from the longitudinal surface of the heater 3 into the
heating chamber 4 and the smokable material 5.
[0064] The heater 3 may optionally comprise a plurality of
individual heating regions 10. The heating regions 10 may be
operable independently of one another so that different regions 10
can be activated at different times to heat the smokable material
5. The heating regions 10 may be arranged in the heater 3 in any
geometric arrangement. However, in the examples shown in the
figures, the heating regions 10 are geometrically arranged in the
heater 3 so that different ones of the heating regions 10 are
arranged to predominately and independently heat different regions
of the smokable material 5.
[0065] For example, referring to FIG. 2, the heater 3 may comprise
a plurality of axially aligned heating regions 10. The regions 10
may each comprise an individual element of the heater 3. The
heating regions 10 may, for example, all be aligned with each other
along a longitudinal axis of the heater 3, thus providing a
plurality of independent heating zones along the length of the
heater 3. Each heating region 10 may comprise a heating cylinder 10
having a finite length which is significantly less than the length
of the heater 3 as a whole. The arrangement and features of the
cylinders 10 are discussed below in terms of heating disks, where
each disk has a depth which is equivalent to cylinder length. The
heating disks 10 are arranged with their radial surfaces facing one
another along the length of the heater 3. The radial surfaces of
each disk 10 may touch the radial surfaces of its neighbouring
disks 10. Alternatively, a heat insulating or heat reflecting layer
may be present between the radial surfaces of the disks 10 so that
thermal energy emitted from each one of the disks 10 does not
substantially heat the neighbouring disks 10 and instead travels
predominately outwards from the circumferential surface of the disk
10 into the heating chamber 4 and smokable material 5. Each disk 10
may have substantially the same dimensions as the other disks
10.
[0066] In this way, when a particular one of the heating regions 10
is activated, it supplies thermal energy to the smokable material 5
located radially around the heating region 10 without substantially
heating the remainder of the smokable material 5.
[0067] For example, referring to FIG. 2, the heated region of
smokable material 5 may comprise a ring of smokable material 5
located around the heating disk 10 which has been activated. The
smokable material 5 can therefore be heated in independent
sections, for example rings, where each section corresponds to
smokable material 5 located directly around a particular one of the
heating regions 10 and has a mass and volume which is significantly
less than the body of smokable material 5 as a whole.
[0068] Additionally or alternatively, referring to FIG. 6, the
heater 3 may comprise a plurality of elongate, longitudinally
extending heating regions 10 positioned at different locations
around the central longitudinal axis of the heater 3. Although
shown as being of different lengths in FIG. 6, the longitudinally
extending heating regions 10 may be of substantially the same
length so that each extends along substantially the whole length of
the heater 3. Each heating region 10 may comprise, for example, an
individual IR heating element 10 such as an IR heating filament 10.
Optionally, a body of heat insulation or heat reflective material
may be provided along the central longitudinal axis of the heater 3
so that thermal energy emitted by each heating region 10 travels
predominately outwards from the heater 3 into the heating chamber 4
and thus heats the smokable material 5. The distance between the
central longitudinal axis of the heater 3 and each of the heating
regions 10 may be substantially equal. The heating regions 10 may
optionally be contained in a substantially infra-red and/or heat
transparent tube, or other housing, which forms a longitudinal
surface of the heater 3. The heating regions 10 may be fixed in
position relative to the other heating regions 10 inside the
tube.
[0069] In this way, when a particular one of the heating regions 10
is activated, it supplies thermal energy to the smokable material 5
located adjacent to the heating region 10 without substantially
heating the remainder of the smokable material 5. The heated
section of smokable material 5 may comprise a longitudinal section
of smokable material 5 which lies parallel and directly adjacent to
the longitudinal heating region 10. Therefore, as with the previous
example, the smokable material 5 can be heated in independent
sections.
[0070] As will be described further below, the heating regions 10
can each be individually and selectively activated.
[0071] The smokable material 5 may be comprised in a cartridge 11
which can be inserted into the heating chamber 4. For example, as
shown in FIG. 1, the cartridge 11 can comprise a smokable material
tube 11 which can be inserted around the heater 3 so that the
internal surface of the smokable material tube 11 faces the
longitudinal surface of the heater 3. The smokable material tube 11
may be hollow. The diameter of the hollow centre of the tube 11 may
be substantially equal to, or slightly larger than, the diameter of
the heater 3 so that the tube 11 is a close fit around the heater
3. The length of the cartridge 11 may be approximately equal to the
length of the heater 3 so that the heater 3 can heat the cartridge
11 along its whole length.
[0072] The housing 7 of the apparatus 1 may comprise an opening
through which the cartridge 11 can be inserted into the heating
chamber 4. The opening may, for example, comprise a ring-shaped
opening located at the housing's second end 9 so that the cartridge
11 can be slid into the opening and pushed directly into the
heating chamber 4. The opening is preferably closed during use of
the apparatus 1 to heat the smokable material 5. Alternatively, a
section of the housing 7 at the second end 9 is removable from the
apparatus 1 so that the smokable material 5 can be inserted into
the heating chamber 4. An example of this is shown in FIG. 9. The
apparatus 1 may optionally be equipped with a user-operable
smokable material ejection unit, such as an internal mechanism
configured to slide used smokable material 5 off and/or away from
the heater 3. The used smokable material 5 may, for example, be
pushed back through the opening in the housing 7. A new cartridge
11 can then be inserted as required.
[0073] In an alternative configuration of heater 3, the heater 3
comprises a spirally shaped heater 3. The spirally shaped heater 3
may be configured to screw into the smokable material cartridge 11
and may comprise adjacent, axially-aligned heating regions 10 so as
to operate in substantially the same manner as described the
linear, elongate heater 3 described above.
[0074] In an alternative configuration of heater 3 and heating
chamber 4, the heater 3 comprises a substantially elongate tube,
which may be cylindrical, and the heating chamber 4 is located
inside the tube 3 rather than around the heater's outside. The
heater 3 may comprise a plurality of axially-aligned heating
sections, which may each comprise a heating ring configured to heat
smokable material 5 located radially inwardly from the ring. In
this way, the heater 3 is configured to independently heat separate
sections of smokable material 5 in the heating chamber 4 in a
manner similar to the heater 3 described above in relation to FIG.
2. The heat is applied radially inwardly to the smokable material
5, rather than radially outwardly as previously described. An
example is shown in FIG. 21.
[0075] Alternatively, referring to FIGS. 7, 8 and 9, a different
geometrical configuration of heater 3 and smokable material 5 can
be used. More particularly, the heater 3 can comprise a plurality
of heating regions 10 which extend directly into an elongate
heating chamber 4 which is divided into sections by the heating
regions 10. During use, the heating regions 10 extend directly into
an elongate smokable material cartridge 11 or other substantially
solid body of smokable material 5. The smokable material 5 in the
heating chamber 4 is thereby divided into discrete sections
separated from each other by the spaced-apart heating regions 10.
The heater 3, heating chamber 4 and smokable material 5 may extend
together along a central, longitudinal axis of the housing 7. As
shown in FIGS. 7 and 9, the heating regions 10 may each comprise a
projection 10, such as an upstanding heating plate 10, which
extends into the body of smokable material 5. The projections 10
are discussed below in the context of heating plates 10. The
principal plane of the heating plates 10 may be substantially
perpendicular to the principal longitudinal axis of the body of
smokable material 5 and heating chamber 4 and/or housing 7. The
heating plates 10 may be parallel to one another, as shown in FIGS.
7 and 9. Each section of smokable material 5 is bounded by a main
heating surface of a pair of heating plates 10 located either side
of the smokable material section, so that activation of one or both
of the heating plates 10 will cause thermal energy to be
transferred directly into the smokable material 5. The heating
surfaces may be embossed to increase the surface area of the
heating plate 10 against the smokable material 5. Optionally, each
heating plate 10 may comprise a thermally reflective layer which
divides the plate 10 into two halves along its principal plane.
Each half of the plate 10 can thus constitute a separate heating
region 10 and may be independently activated to heat only the
section of smokable material 5 which lies directly against that
half of the plate 10, rather than the smokable material 5 on both
sides of the plate 10. Adjacent plates 10, or facing portions
thereof, may be activated to heat a section of smokable material 5,
which is located between the adjacent plates, from substantially
opposite sides of the section of smokable material 5.
[0076] The elongate smokable material cartridge or body 11 can be
installed between, and removed from, the heating chamber 4 and
heating plates 10 by removing a section of the housing 7 at the
housing's second end 9, as previously described. The heating
regions 10 can be individually and selectively activated to heat
different sections of the smokable material 5 as required.
[0077] In this way, when a particular one or pair of the heating
regions 10 is activated, it supplies thermal energy to the smokable
material 5 located directly adjacent to the heating region(s) 10
without substantially heating the remainder of the smokable
material 5. The heated section of smokable material 5 may comprise
a radial section of smokable material 5 located between the heating
regions 10, as shown in FIGS. 7 to 9.
[0078] The apparatus 1 may comprise a controller 12, such as a
microcontroller 12, which is configured to control operation of the
apparatus 1. The controller 12 is electronically connected to the
other components of the apparatus 1 such as the energy source 2 and
heater 3 so that it can control their operation by sending and
receiving signals. The controller 12 is, in particular, configured
to control activation of the heater 3 to heat the smokable material
5. For example, the controller 12 may be configured to activate the
heater 3, which may comprise selectively activating one or more
heating regions 10, in response to a user drawing on the mouthpiece
6 of the apparatus 1. In this regard, the controller 12 may be in
communication with a puff sensor 13 via a suitable communicative
coupling. The puff sensor 13 is configured to detect when a puff
occurs at the mouthpiece 6 and, in response, is configured to send
a signal to the controller 12 indicative of the puff. An electronic
signal may be used. The controller 12 may respond to the signal
from the puff sensor 13 by activating the heater 3 and thereby
heating the smokable material 5. The use of a puff sensor 13 to
activate the heater 3 is not, however, essential and other means
for providing a stimulus to activate the heater 3 can alternatively
be used. For example, the controller 12 may activate the heater 3
in response to another type of activation stimulus such as
actuation of a user-operable actuator. The volatilized compounds
released during heating can then be inhaled by the user through the
mouthpiece 6. The controller 12 can be located at any suitable
position within the housing 7. An example position is between the
energy source 2 and the heater 3/heating chamber 4, as illustrated
in FIG. 3.
[0079] If the heater 3 comprises two or more heating regions 10 as
described above, the controller 12 may be configured to activate
the heating regions 10 in a predetermined order or pattern. For
example, the controller 12 may be configured to activate the
heating regions 10 sequentially along or around the heating chamber
4. Each activation of a heating region 10 may be in response to
detection of a puff by the puff sensor 13 or may be triggered in an
alternative way, as described further below.
[0080] Referring to FIG. 10, an example heating method may comprise
a first step S1 in which an activation stimulus such as a first
puff is detected followed by a second step S2 in which a first
section of smokable material 5 is heated in response to the first
puff or other activation stimulus. In a third step S3, hermetically
sealable inlet and outlet valves 24 may be opened to allow air to
be drawn through the heating chamber 4 and out of the apparatus 1
through the mouthpiece 6. In a fourth step, the valves 24 are
closed. These valves 24 are described in more detail below with
respect to FIG. 20. In fifth S5, sixth S6, seventh S7 and eighth S8
steps, a second section of smokable material 5 may be heated in
response to a second activation stimulus such as a second puff,
with a corresponding opening and closing of the heating chamber
inlet and outlet valves 24. In ninth S9, tenth S10, eleventh S11
and twelfth S12 steps, a third section of the smokable material 5
may be heated in response to a third activation stimulus such as a
third puff with a corresponding opening and closing of the heating
chamber inlet and outlet valves 24, and so on. As referred to
above, means other than a puff sensor 13 could alternatively be
used. For example, a user of the apparatus 1 may actuate a control
switch to indicate that he/she is taking a new puff. In this way, a
fresh section of smokable material 5 may be heated to volatilize
nicotine and aromatic compounds for each new puff. The number of
heating regions 10 and/or independently heatable sections of
smokable material 5 may correspond to the number of puffs for which
the cartridge 11 is intended to be used. Alternatively, each
independently heatable smokable material section 5 may be heated by
its corresponding heating region(s) 10 for a plurality of puffs
such as two, three or four puffs, so that a fresh section of
smokable material 5 is heated only after a plurality of puffs have
been taken whilst heating the previous smokable material
section.
[0081] Instead of activating each heating region 10 in response to
an individual puff, the heating regions 10 may alternatively be
activated sequentially, one after the other, in response to a
single, initial puff at the mouthpiece 6. For example, the heating
regions 10 may be activated at regular, predetermined intervals
over the expected inhalation period for a particular smokable
material cartridge 11. The inhalation period may, for example, be
between approximately one and approximately four minutes.
Therefore, at least the fifth and ninth steps S5, S9 shown in FIG.
10 are optional. Each heating region 10 may be activated for a
predetermined period corresponding to the duration of the single or
plurality of puffs for which the corresponding independently
heatable smokable material section 5 is intended to be heated. Once
all of the heating regions 10 have been activated for a particular
cartridge 11, the controller 12 may be configured to indicate to
the user that the cartridge 11 should be changed. The controller 12
may, for example, activate an indicator light at the external
surface of the housing 7.
[0082] It will be appreciated that activating individual heating
regions 10 in order rather than activating the entire heater 3
means that the energy required to heat the smokable material 5 is
reduced over what would be required if the heater 3 were activated
fully over the entire inhalation period of a cartridge 11.
Therefore, the maximum required power output of the energy source 2
is also reduced. This means that a smaller and lighter energy
source 2 can be installed in the apparatus 1.
[0083] The controller 12 may be configured to de-activate the
heater 3, or reduce the power being supplied to the heater 3, in
between puffs. This saves energy and extends the life of the energy
source 2. For example, upon the apparatus 1 being switched on by a
user or in response to some other stimulus, such as detection of a
user placing their mouth against the mouthpiece 6, the controller
12 may be configured to cause the heater 3, or next heating region
10 to be used to heat the smokable material 5, to be partially
activated so that it heats up in preparation to volatilize
components of the smokable material 5. The partial activation does
not heat the smokable material 5 to a sufficient temperature to
volatilize nicotine. A suitable temperature could be below
120.degree. C., such as 100.degree. C. or below. An example is a
temperature between 60.degree. C. and 100.degree. C., such as a
temperature between 80.degree. C. and 100.degree. C. The
temperature may be less than 100.degree. C. In response to
detection of a puff by the puff sensor 13, the controller 12 can
then cause the heater 3 or heating region 10 in question to heat
the smokable material 5 further in order to rapidly volatilize the
nicotine and other aromatic compounds for inhalation by the user.
If the smokable material 5 comprises tobacco, a suitable
temperature for volatilizing the nicotine and other aromatic
compounds may be 100.degree. C. or above, such as 120.degree. C. or
above. An example is a temperature between 100.degree. C. and
250.degree. C., such as between 150.degree. C. and 250.degree. C.
or between 130.degree. C. and 180.degree. C. The temperature may be
more than 100.degree. C. An example full activation temperature is
150.degree. C., although other values such as 250.degree. C. are
also possible. A super-capacitor can optionally be used to provide
the peak current used to heat the smokable material 5 to the
volatization temperature. An example of a suitable heating pattern
is shown in FIG. 12, in which the peaks may respectively represent
the full activation of different heating regions 10. As can be
seen, the smokable material 5 is maintained at the volatization
temperature for the approximate period of the puff which, in this
example, is two seconds.
[0084] Three example operational modes of the heater 3 are
described below.
[0085] In a first operational mode, during full activation of a
particular heating region 10, all other heating regions 10 of the
heater are deactivated. Therefore, when a new heating region 10 is
activated, the previous heating region is deactivated. Power is
supplied only to the activated region 10.
[0086] Alternatively, in a second operational mode, during full
activation of a particular heating region 10, one or more of the
other heating regions 10 may be partially activated. Partial
activation of the one or more other heating regions 10 may comprise
heating the other heating region(s) 10 to a temperature which is
sufficient to substantially prevent condensation of components such
as nicotine volatized from the smokable material 5 in the heating
chamber 4. The temperature of the heating regions 10 which are
partially activated is less than the temperature of the heating
region 10 which is fully activated. The smokable material 10
located adjacent the partially activated regions 10 is not heated
to a temperature sufficient to volatize components of the smokable
material 5.
[0087] Alternatively, in a third operational mode, once a
particular heating region 10 has been activated, it remains fully
activated until the heater 3 is switched off. Therefore, the power
supplied to the heater 3 incrementally increases as more of the
heating regions 10 are activated during inhalation from the
cartridge 11. As with the second mode previously described, the
continuing activation of the heating regions 10 substantially
prevent condensation of components such as nicotine volatized from
the smokable material 5 in the heating chamber 4.
[0088] The apparatus 1 may comprise a heat shield 3a, which is
located between the heater 3 and the heating chamber 4/smokable
material 5. The heat shield 3a is configured to substantially
prevent thermal energy from flowing through the heat shield 3a and
therefore can be used to selectively prevent the smokable material
5 from being heated even when the heater 3 is activated and
emitting thermal energy. Referring to FIG. 19, the heat shield 3a
may, for example, comprise a cylindrical layer of heat reflective
material which is located co-axially around the heater 3.
Alternatively, if the heater 3 is located around the heating
chamber 4 and smokable material 5 as previously described, the heat
shield 3a may comprise a cylindrical layer of heat reflective
material which is located co-axially around the heating chamber 4
and co-axially inside of the heater 3. The heat shield 3a may
additionally or alternatively comprise a heat-insulating layer
configured to insulate the heater 3 from the smokable material 5.
The heat shield 3a comprises a substantially heat-transparent
window 3b which allows thermal energy to propagate through the
window 3b and into the heating chamber 4 and smokable material 5.
Therefore, the section of smokable material 5 which is aligned with
the window 3b is heated whilst the remainder of the smokable
material 5 is not. The heat shield 3a and window 3b may be
rotatable or otherwise moveable with respect to the smokable
material 5 so that different sections of the smokable material 5
can be selectively and individually heated by rotating or moving
the heat shield 3a and window 3b. The effect is similar to the
effect provided by selectively and individually activating the
heating regions 10 referred to above. For example, the heat shield
3a and window 3b may be rotated or otherwise moved incrementally in
response to a signal from the puff detector 13. Additionally or
alternatively, the heat shield 3a and window 3b may be rotated or
otherwise moved incrementally in response to a predetermined
heating period having elapsed. Movement or rotation of the heat
shield 3a and window 3b may be controlled by electronic signals
from the controller 12. The relative rotation or other movement of
the heat shield 3a/window 3b and smokable material 5 may be driven
by a stepper motor 3c under the control of the controller 12. This
is illustrated in FIG. 19. Alternatively, the heat shield 3a and
window 3b may be manually rotated using a user control such as an
actuator on the housing 7. The heat shield 3a does not need to be
cylindrical and may comprise optionally comprise one or more
suitably positioned longitudinally extending elements and
or/plates.
[0089] It will be appreciated that a similar result can be obtained
by rotating or moving the smokable material 5 relative to the
heater 3, heat shield 3a and window 3b. For example, the heating
chamber 4 may be rotatable around the heater 3. If this is the
case, the above description relating to movement of the heat shield
3a can be applied instead to movement of the heating chamber 4
relative to the heat shield 3a.
[0090] The heat shield 3a may comprise a coating on the
longitudinal surface of the heater 3. In this case, an area of the
heater's surface is left uncoated to form the heat-transparent
window 3b. The heater 3 can be rotated or otherwise moved, for
example under the control of the controller 12 or user controls, to
cause different sections of the smokable material 5 to be heated.
Alternatively, the heat shield 3a and window 3b may comprise a
separate shield 3a which is rotatable or otherwise moveable
relative to both the heater 3 and the smokable material 5 under the
control of the controller 12 or other user controls.
[0091] Referring to FIG. 6, the apparatus 1 may comprise air inlets
14 which allow external air to be drawn into the housing 7 and
through the heated smokable material 5 during puffing. The air
inlets 14 may comprise apertures 14 in the housing 7 and may be
located upstream from the smokable material 5 and heating chamber 4
towards the first end 8 of the housing 7. This is shown in FIG. 1.
Another example is shown in FIG. 11. Air drawn in through the
inlets 14 travels through the heated smokable material 5 and
therein is enriched with smokable material vapours, such as aroma
vapours, before being inhaled by the user at the mouthpiece 6.
Optionally, as shown in FIG. 11, the apparatus 1 may comprise a
heat exchanger 15 configured to warm the air before it enters the
smokable material 5 and/or to cool the air before it is drawn
through the mouthpiece 6. For example, the heat exchanger 15 may be
configured to use heat extracted from the air entering the
mouthpiece 6 to warm new air before it enters the smokable material
5.
[0092] The apparatus 1 may comprise a smokable material compressor
16 configured to cause the smokable material 5 to compress upon
activation of the compressor 16. The apparatus 1 can also comprise
a smokable material expander 17 configured to cause the smokable
material 5 to expand upon activation of the expander 17. The
compressor 16 and expander 17 may, in practice, be implemented as
the same unit as will be explained below. The smokable material
compressor 16 and expander 17 may optionally operate under the
control of the controller 12. In this case, the controller 12 is
configured to send a signal, such as an electrical signal, to the
compressor 16 or expander 17 which causes the compressor 16 or
expander 17 to respectively compress or expand the smokable
material 5. Alternatively, the compressor 16 and expander 17 may be
actuated by a user of the apparatus 1 using a manual control on the
housing 7 to compress or expand the smokable material 5 as
required.
[0093] The compressor 16 is principally configured to compress the
smokable material 5 and thereby increase its density during
heating. Compression of the smokable material increases the thermal
conductivity of the body of smokable material 5 and therefore
provides a more rapid heating and consequent rapid volatization of
nicotine and other aromatic compounds. This is preferable because
it allows the nicotine and aromatics to be inhaled by the user
without substantial delay in response to detection of a puff.
Therefore, the controller 12 may activate the compressor 16 to
compress the smokable material 5 for predetermined heating period,
for example one second, in response to detection of a puff. The
compressor 16 may be configured to reduce its compression of the
smokable material 5, for example under the control of the
controller 12, after the predetermined heating period.
Alternatively, the compression may be reduced or automatically
ended in response to the smokable material 5 reaching a
predetermined threshold temperature. A suitable threshold
temperature may be in the range of approximately 100.degree. C. to
250.degree. C., such as between 100.degree. C. and 220.degree. C.,
between 150.degree. C. and 250.degree. C., between 100.degree. C.
and 200.degree. C. or between 130.degree. C. and 180.degree. C. The
threshold temperature may be above 100.degree. C., such as a value
above 120.degree. C., and may be user selectable. A temperature
sensor may be used to detect the temperature of the smokable
material 5.
[0094] The expander 17 is principally configured to expand the
smokable material 5 and thereby decrease its density during
puffing. The arrangement of smokable material 5 in the heating
chamber 4 becomes more loose when the smokable material 5 has been
expanded and this aids the gaseous flow, for example air from the
inlets 14, through the smokable material 5. The air is therefore
more able to carry the volatilized nicotine and aromatics to the
mouthpiece 6 for inhalation. The controller 12 may activate the
expander 17 to expand the smokable material 5 immediately following
the compression period referred to above so that air can be drawn
more freely through the smokable material 5. Actuation of the
expander 17 may be accompanied by a user-audible sound or other
indication to indicate to the user that the smokable material 5 has
been heated and that puffing can commence.
[0095] Referring to FIGS. 13 and 14, the compressor 16 and expander
17 may comprise a spring-actuated driving rod which is configured
to compress the smokable material 5 in the heating chamber 4 when
the spring is released from compression. This is schematically
illustrated in FIGS. 13 and 14, although it will be appreciated
that other implementations could be used. For example, the
compressor 16 may comprise a ring, having a thickness approximately
equal to the tubular-shaped heating chamber 4 described above,
which is driven by a spring or other means into the heating chamber
4 to compress the smokable material 5. Alternatively, the
compressor 16 may be comprised as part of the heater 3 so that the
heater 3 itself is configured to compress and expand the smokable
material 5 under the control of the controller 12. For example,
where the heater 3 comprises upstanding heating plates 10 of the
type previously described, the plates 10 may be independently
moveable in a longitudinal direction of the heater 3 to expand or
compress the sections of smokable material 5 which are located
adjacent to them. A method of compressing and expanding the
smokable material 5 is shown in FIG. 15.
[0096] Thermal insulation 18 may be provided between the smokable
material 5 and an external surface 19 of the housing 7 to reduce
heat loss from the apparatus 1 and therefore improve the efficiency
with which the smokable material 5 is heated. For example,
referring to FIG. 1, a wall of the housing 7 may comprise a layer
of insulation 18 which extends around the outside of the heating
chamber 4. The insulation layer 18 may comprise a substantially
tubular length of insulation 18 located co-axially around the
heating chamber 4 and smokable material 5. This is shown in FIG. 1.
Another example is shown in FIG. 21. It will be appreciated that
the insulation 18 could also be comprised as part of the smokable
material cartridge 11, in which it would be located co-axially
around the outside of the smokable material 5.
[0097] Referring to FIG. 16, the insulation 18 may comprise vacuum
insulation 18. For example, the insulation 18 may comprise a layer
which is bounded by a wall material 19 such as a metallic material.
An internal region or core 20 of the insulation 18 may comprise an
open-cell porous material, for example comprising polymers,
aerogels or other suitable material, which is evacuated to a low
pressure. The pressure in the internal region 20 may be in the
range of 0.1 to 0.001 mbar. The wall 19 of the insulation 18 is
sufficiently strong to withstand the force exerted against it due
to the pressure differential between the core 20 and external
surfaces of the wall 19, thereby preventing the insulation 18 from
collapsing. The wall 19 may, for example, comprise a stainless
steel wall 19 having a thickness of approximately 100 .mu.m. The
thermal conductivity of the insulation 18 may be in the range of
0.004 to 0.005 W/m/K. The heat transfer coefficient of the
insulation 18 may be between approximately 1.10 W/(m.sup.2K) and
approximately 1.40 W/(m.sup.2K) within a temperature range of
between 100 degrees Celsius and 250 degrees Celsius, such as
between approximately 150 degrees Celsius and approximately 250
degrees Celsius. The gaseous conductivity of the insulation 18 is
negligible. A reflective coating may be applied to the internal
surfaces of the wall material 19 to minimize heat losses due to
radiation propagating through the insulation 18. The coating may,
for example, comprise an aluminium IR reflective coating having a
thickness of between approximately 0.3 .mu.m and 1.0 .mu.m. The
evacuated state of the internal core region 20 means that the
insulation 18 functions even when the thickness of the core region
20 is very small. The insulating properties are substantially
unaffected by its thickness. This helps to reduce the overall size
of the apparatus 1.
[0098] As shown in FIG. 16, the wall 19 may comprise an
inwardly-facing section 21 and an outwardly-facing section 22. The
inwardly-facing section 21 substantially faces the smokable
material 5 and heating chamber 4. The outwardly-facing section 22
substantially faces the exterior of the housing 7. During operation
of the apparatus 1, the inwardly-facing section 21 may be warmer
due to the thermal energy originating from the heater 3, whilst the
outwardly-facing section 22 is cooler due to the effect of the
insulation 18. The inwardly-facing section 21 and the
outwardly-facing section 22 may, for example, comprise
substantially parallel longitudinally-extending walls 19 which are
at least as long as the heater 3. The internal surface of the
outwardly-facing wall section 22, i.e. the surface facing the
evacuated core region 20, may comprise a coating for absorbing gas
in the core 20. A suitable coating is a titanium oxide film.
[0099] The thermal insulation 18 may comprise hyper-deep vacuum
insulation such as an Insulon.RTM. Shaped-Vacuum Thermal Barrier as
described in U.S. Pat. No. 7,374,063. The overall thickness of such
insulation 18 may be extremely small. An example thickness is
between approximately 1 mm and approximately 1 .mu.m, such as
approximately 0.1 mm, although other larger or smaller thicknesses
are also possible. The thermally insulating properties of the
insulation 18 are substantially unaffected by its thickness and
therefore thin insulation 18 can be used without any substantial
additional heat loss from the apparatus 1. The very small thickness
of the thermal insulation 18 may allow the size of the housing 7
and apparatus 1 as a whole to be reduced beyond the sizes
previously discussed and may allow the thickness, for example the
diameter, of the apparatus 1 to be approximately equal to smoking
articles such as cigarettes, cigars and cigarillos. The weight of
the apparatus 1 may also be reduced, providing similar benefits to
the size reductions discussed above.
[0100] Although the thermal insulation 18 described previously may
comprise a gas-absorbing material to maintain or aid with creation
of the vacuum in the core region 20, a gas absorbing material is
not used in the deep-vacuum insulation 18. The absence of the gas
absorbing material aids with keeping the thickness of the
insulation 18 very low and thus helps to reduce the overall size of
the apparatus 1.
[0101] The geometry of the hyper-deep insulation 18 allows the
vacuum in the insulation to be deeper than the vacuum used to
extract molecules from the core region 20 of the insulation 18
during manufacture. For example, the deep vacuum inside the
insulation 18 may be deeper than that of the vacuum-furnace chamber
in which it is created. The vacuum inside the insulation 18 may,
for example, be of the order 10.sup.-7 Torr. Referring to FIG. 22,
an end of the core region 20 of the deep-vacuum insulation 18 may
taper as the outwardly facing section 22 and inwardly facing
section 21 converge to an outlet 25 through which gas in the core
region 20 may be evacuated to create a deep vacuum during
manufacture of the insulation 18. FIG. 22 illustrates the outwardly
facing section 22 converging towards the inwardly facing section 21
but a converse arrangement, in which the inwardly facing section 21
converges to the outwardly facing section 22, could alternatively
be used. The converging end of the insulating wall 19 is configured
to guide gas molecules in the core region 20 out of the outlet 25
and thereby create a deep vacuum in the core 20. The outlet 25 is
sealable so as to maintain a deep vacuum in the core region 20
after the region 20 has been evacuated. The outlet 25 can be
sealed, for example, by creating a brazed seal at the outlet 25 by
heating brazing material at the outlet 25 after gas has been
evacuated from the core 20. Alternative sealing techniques could be
used.
[0102] In order to evacuate the core region 20, the insulation 18
may be placed in a low pressure, substantially evacuated
environment such as a vacuum furnace chamber so that gas molecules
in the core region 20 flow into the low pressure environment
outside the insulation 18. When the pressure inside the core region
20 becomes low, the tapered geometry of the core region 20, and in
particular the converging sections 21, 22 referred to above,
becomes influential in guiding remaining gas molecules out the core
20 via the outlet 25. Specifically, when the gas pressure in the
core region 20 is low, the guiding effect of the converging
inwardly and outwardly facing sections 21, 22 is effective to
channel the remaining gas molecules inside the core 20 towards the
outlet 25 and make the probability of gas exiting the core 20
higher than the probability of gas entering the core 20 from the
external, low pressure environment. In this way, the geometry of
the core 20 allows the pressure inside the core 20 to be reduced
below the pressure of the environment outside the insulation
18.
[0103] Optionally, as previously described, one or more low
emissivity coatings may be present on the internal surfaces of the
inwardly and outwardly facing sections 21, 22 of the wall 19 in
order to substantially prevent heat losses by radiation.
[0104] Although the shape of the insulation 18 is generally
described herein as substantially cylindrical or similar, the
thermal insulation 18 could be another shape, for example in order
to accommodate and insulate a different configuration of the
apparatus 1 such as different shapes and sizes of heating chamber
4, heater 3, housing 7 or energy source 2. For example, the size
and shape of deep-vacuum insulation 18 such as an Insulon.RTM.
Shaped-Vacuum Thermal Barrier referred to above is substantially
unlimited by its manufacturing process. Suitable materials for
forming the converging structure described above include ceramics,
metals, metalloids and combinations of these.
[0105] Referring to the schematic illustration in FIG. 17, a
thermal bridge 23 may connect the inwardly-facing wall section 21
to the outwardly-facing wall section 22 at one or more edges of the
insulation 18 in order to completely encompass and contain the low
pressure core 20. The thermal bridge 23 may comprise a wall 19
formed of the same material as the inwardly and outwardly-facing
sections 21, 22. A suitable material is stainless steel, as
previously discussed. The thermal bridge 23 has a greater thermal
conductivity than the insulating core 20 and therefore may
undesirably conduct heat out of the apparatus 1 and, in doing so,
reduce the efficiency with which the smokable material 5 is
heated.
[0106] To reduce heat losses due to the thermal bridge 23, the
thermal bridge 23 may be extended to increase its resistance to
heat flow from the inwardly-facing section 21 to the
outwardly-facing section 22. This is schematically illustrated in
FIG. 18. For example, the thermal bridge 23 may follow an indirect
path between the inwardly-facing section 21 of wall 19 and the
outwardly-facing section 22 of wall 19. This may be facilitated by
providing the insulation 18 over a longitudinal distance which is
longer than the lengths of the heater 3, heating chamber 4 and
smokable material 5 so that the thermal bridge 23 can gradually
extend from the inwardly-facing section 21 to the outwardly-facing
section 22 along the indirect path, thereby reducing the thickness
of the core 20 to zero, at a longitudinal location in the housing 7
where the heater 3, heating chamber 4 and smokable material 5 are
not present.
[0107] Referring to FIG. 20, as previously discussed, the heating
chamber 4 insulated by the insulation 18 may comprise inlet and
outlet valves 24 which hermetically seal the heating chamber 4 when
closed. The valves 24 can thereby prevent air from undesirably
entering and exiting the chamber 4 and can prevent smokable
material flavours from exiting the chamber 4. The inlet and outlet
values 24 may, for example, be provided in the insulation 18. For
example, between puffs, the valves 24 may be closed by the
controller 12 so that all volatilized substances remain contained
inside the chamber 4 in-between puffs. The partial pressure of the
volatized substances between puffs reaches the saturated vapour
pressure and the amount of evaporated substances therefore depends
only on the temperature in the heating chamber 4. This helps to
ensure that the delivery of volatilized nicotine and aromatic
compounds remains constant from puff to puff. During puffing, the
controller 12 is configured to open the valves 24 so that air can
flow through the chamber 4 to carry volatilized smokable material
components to the mouthpiece 6. A membrane can be located in the
valves 24 to ensure that no oxygen enters the chamber 4. The valves
24 may be breath-actuated so that the valves 24 open in response to
detection of a puff at the mouthpiece 6. The valves 24 may close in
response to a detection that a puff has ended. Alternatively, the
valves 24 may close following the elapse of a predetermined period
after their opening. The predetermined period may be timed by the
controller 12. Optionally, a mechanical or other suitable
opening/closing means may be present so that the valves 24 open and
close automatically. For example, the gaseous movement caused by a
user puffing on the mouthpiece 6 may be used to open and close the
valves 24. Therefore, the use of the controller 12 is not
necessarily required to actuate the valves 24.
[0108] The mass of the smokable material 5 which is heated by the
heater 3, for example by each heating region 10, may be in the
range of 0.2 to 1.0 g. The temperature to which the smokable
material 5 is heated may be user controllable, for example to any
temperature within the temperature range of 100.degree. C. to
250.degree. C., such as any temperature within the range of
150.degree. C. to 250.degree. C. or the other volatizing
temperature ranges previously described. The mass of the apparatus
1 as a whole may be in the range of 70 to 125 g. A battery 2 with a
capacity of 1000 to 3000 mAh and voltage of 3.7V can be used. The
heating regions 10 may be configured to individually and
selectively heat between approximately 10 and 40 sections of
smokable material 5 for a single cartridge 11.
[0109] It will be appreciated that any of the alternatives
described above can be used singly or in combination. For example,
as discussed above, the heater 3 may be located around the outside
of the smokable material 5 rather than the smokable material 5
being located around the heater 3. The heater 3 may therefore
circumscribe the smokable material 5 to apply heat to the smokable
material 5 in a substantially radially inward direction.
[0110] In order to address various issues and advance the art, the
entirety of this disclosure shows by way of illustration various
embodiments in which the claimed invention(s) may be practiced and
provide for superior apparatus. The advantages and features of the
disclosure are of a representative sample of embodiments only, and
are not exhaustive and/or exclusive. They are presented only to
assist in understanding and teach the claimed features. It is to be
understood that advantages, embodiments, examples, functions,
features, structures, and/or other aspects of the disclosure are
not to be considered limitations on the disclosure as defined by
the claims or limitations on equivalents to the claims, and that
other embodiments may be utilised and modifications may be made
without departing from the scope and/or spirit of the disclosure.
Various embodiments may suitably comprise, consist of, or consist
essentially of, various combinations of the disclosed elements,
components, features, parts, steps, means, etc. In addition, the
disclosure includes other inventions not presently claimed, but
which may be claimed in future.
* * * * *