U.S. patent application number 14/779210 was filed with the patent office on 2016-02-18 for heating smokeable material.
This patent application is currently assigned to BRITISH AMERICAN TOBACCO (INVESTMENTS) LIMITED. The applicant listed for this patent is BRITISH AMERICAN TOBACCO (INVESTMENTS LIMITED). Invention is credited to Fozia SALEEM.
Application Number | 20160044963 14/779210 |
Document ID | / |
Family ID | 48226885 |
Filed Date | 2016-02-18 |
United States Patent
Application |
20160044963 |
Kind Code |
A1 |
SALEEM; Fozia |
February 18, 2016 |
HEATING SMOKEABLE MATERIAL
Abstract
An apparatus configured to heat smokeable material so as to
volatilize at least one of its components for inhalation comprises
at least one heating element (3b) on or in a substrate material
(3a).
Inventors: |
SALEEM; Fozia; (London,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BRITISH AMERICAN TOBACCO (INVESTMENTS LIMITED) |
London |
|
GB |
|
|
Assignee: |
BRITISH AMERICAN TOBACCO
(INVESTMENTS) LIMITED
London
GB
|
Family ID: |
48226885 |
Appl. No.: |
14/779210 |
Filed: |
March 19, 2014 |
PCT Filed: |
March 19, 2014 |
PCT NO: |
PCT/EP2014/055485 |
371 Date: |
September 22, 2015 |
Current U.S.
Class: |
131/328 ;
131/329 |
Current CPC
Class: |
A61M 2016/0015 20130101;
H05B 3/0014 20130101; A61M 15/06 20130101; H05B 3/44 20130101; A61M
2205/8206 20130101; A24F 47/008 20130101; A61M 2205/3368 20130101;
H05B 2203/021 20130101; A61M 2205/3653 20130101; H05B 2203/022
20130101; H05B 2203/013 20130101; A61M 2205/3633 20130101; A61M
11/042 20140204; H05B 3/06 20130101 |
International
Class: |
A24F 47/00 20060101
A24F047/00; H05B 3/06 20060101 H05B003/06; H05B 3/00 20060101
H05B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2013 |
GB |
1305294.9 |
Claims
1. A smokeable material heater apparatus, comprising: a substrate,
and at least one printed heater element configured to, in use, heat
the substrate to a smokeable material volatilizing temperature at
which the substrate volatilizes at least one component of a
smokeable material for inhalation.
2. The apparatus according to claim 1, wherein the at least one
printed heater element is disposed at least partially inside the
substrate.
3. The apparatus according to claim 1, wherein a coefficient of
thermal expansion of the at least one printed heater element is
substantially equal to a coefficient of thermal expansion of the
substrate.
4. The apparatus according to claim 1, wherein the at least one
printed heater element is chemically bonded to the substrate.
5. The apparatus according claim 1, wherein the at least one
printed heater element and the substrate comprise a single sintered
structure.
6. The apparatus according to claim 1, wherein the at least one
printed heater element includes an electrically resistive trace in
the substrate.
7. The apparatus according to claim 1, wherein the substrate
includes a ceramics material.
8. The apparatus according to claim 1, wherein the substrate is
proximal a smokeable material heat chamber configured to contain a
body of smokeable material during heating.
9. The apparatus according to claim 1, wherein a plurality of
heater elements are arranged in layers inside the substrate.
10. The apparatus according to claim 9, wherein the layers are
interconnected by heater element vias through the substrate.
11. An apparatus, comprising: a heater configured to heat smokeable
material to volatilize at least one component of the smokeable
material for inhalation, the heater including a substrate and a
heater element, a coefficient of thermal expansion of the substrate
being substantially equal to a coefficient of thermal expansion of
the heater element.
12. (canceled)
13. The apparatus according to claim 11, wherein the heater element
is configured to heat the substrate to a temperature sufficient to
volatilize at least one component of smokeable material disposed in
an adjacent smokeable material heat chamber.
14. The apparatus according to claim 11, wherein the heater element
is disposed at least partially inside the substrate.
15. The apparatus according to claim 11, wherein the heater element
is chemically bonded to the substrate.
16. The apparatus according to claim 11, wherein the heater
includes a sintered structure comprising the heater element and the
substrate.
17. The apparatus according to claim 11, wherein the heater element
comprises an electrically resistive trace in the substrate and/or
the substrate comprises a ceramics material.
18. The apparatus according to claim 11, wherein a plurality of
heater elements are arranged in layers inside the substrate.
19. The apparatus according to claim 18, wherein the layers are
interconnected by heater element vias through the substrate.
20. An apparatus, comprising: a heater configured to heat smokeable
material to volatilize at least one component of the smokeable
material for inhalation, the heater including a multiple layered
structure of ceramic material and electrically resistive heater
elements.
21. The apparatus according to claim 20, wherein the heater
elements include electrically resistive traces in the ceramic
material.
22. The apparatus according to claim 20, wherein the heater
elements are chemically bonded to the ceramic material in a
sintered structure.
23. (canceled)
24. The apparatus according to claim 20, wherein the heater
elements include Tungsten and the ceramic material includes
Aluminum Nitride Ceramic.
25. (canceled)
26. The apparatus according to claim 20, wherein the heater
elements are configured to heat the ceramic material to a
temperature sufficient to volatilize at least one component of
smokeable material disposed in a heat chamber adjacent the ceramic
material.
27. The apparatus according to claim 20, wherein the heater
elements are disposed inside the ceramic material.
28. The apparatus according to claim 20, wherein the heater
elements of the multiple layered structure are interconnected by
heater element vias through the ceramic material.
29. An apparatus, comprising: a heater configured to heat smokeable
material, the heater including a substrate, and at least one heater
element disposed inside the substrate and configured to, in use,
heat the substrate such that the heated substrate volatilizes at
least one component of a smokeable material for inhalation.
30-31. (canceled)
32. The apparatus according to claim 29, wherein the at least one
heater element and the substrate are sintered to form a chemically
bonded structure.
33. The apparatus according to claim 29, wherein the substrate
includes a ceramics material and the heater element includes an
electrically resistive trace material.
34. The apparatus according to claim 29, wherein the substrate is
proximal a smokeable material heat chamber configured to contain a
body of smokeable material during heating.
35. The apparatus according to claim 29, wherein the heater
includes comprising a plurality of heater elements arranged in
layers inside the substrate.
36. The apparatus according to claim 35, wherein the layers are
interconnected by heater element vias through the substrate.
37. The apparatus according to claim 1, wherein the apparatus is
configured to heat the smokeable material to a temperature of at
least 120 degrees Celsius.
38. The apparatus according to claim 1, wherein the apparatus is
configured to heat the smokeable material to a temperature of
between 120 degrees Celsius and 250 degrees Celsius.
39. The apparatus according to claim 1, wherein the apparatus is
configured to heat the smokeable material to a smokeable material
volatilizing temperature of between 130 degrees Celsius and 180
degrees Celsius.
40-43. (canceled)
44. A method of heating smokeable material using the apparatus of
claim 1, the method comprising; heating the substrate to the
smokeable material volatilizing temperature using the at least one
printed heater element, causing the heated substrate to volatilize
at least one component of the smokeable material for
inhalation.
45. A method of heating smokeable material using the apparatus of
claim 29, the method comprising: heating the substrate to a
smokeable material volatilizing temperature using the at least one
heater element disposed inside the substrate such that the heated
substrate volatilizes at least one component of smokeable material
for inhalation.
Description
FIELD
[0001] The invention relates to heating smokeable material.
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.
SUMMARY
[0003] According to the invention, there is provided a smokeable
material heating apparatus comprising a substrate and at least one
printed heating element arranged to heat the substrate to a
smokeable material volatilizing temperature and thereby cause the
substrate to volatilize at least one component of smokeable
material for inhalation.
[0004] The heating element may be located at least partially inside
the substrate.
[0005] The coefficient of thermal expansion of the heating element
may be substantially equal to the coefficient of thermal expansion
of the substrate.
[0006] The heating element may be chemically bonded to the
substrate.
[0007] The heating element and the substrate may comprise a single
sintered structure.
[0008] The heating element may comprise an electrically resistive
trace in the substrate.
[0009] The substrate may comprise a ceramics material.
[0010] The substrate may be proximal a smokeable material heating
chamber configured to contain the body of smokeable material during
heating.
[0011] The apparatus may comprise a plurality of the heating
elements arranged in layers inside the substrate.
[0012] The layers of heating elements may be interconnected by
heating element vias through the substrate.
[0013] According to the invention, there is also provided an
apparatus comprising a heater configured to heat smokeable material
to volatilize at least one component of the smokeable material for
inhalation, wherein the heater comprises a substrate and a heating
element with substantially equal coefficients of thermal
expansion.
[0014] The heating element may be printed to the substrate.
[0015] The heating element may be arranged to heat the substrate to
a temperature sufficient for the substrate to volatilize at least
one component of smokeable material located in an adjacent
smokeable material heating chamber.
[0016] The heating element may be located at least partially inside
the substrate.
[0017] The heating element may be chemically bonded to the
substrate.
[0018] The heater may comprise a sintered structure comprising the
heating element and the substrate.
[0019] The heating element may comprise an electrically resistive
trace in the substrate and/or the substrate may comprise a ceramics
material.
[0020] The apparatus may comprise a plurality of the heating
elements arranged in layers inside the substrate.
[0021] The layers of heating elements may be interconnected by
heating element vias through the substrate.
[0022] According to the invention, there is also provided an
apparatus comprising a heater configured to heat smokeable material
to volatilize at least one component of the smokeable material for
inhalation, wherein the heater comprises a multiply layered
structure of ceramic material and electrically resistive heating
elements.
[0023] The heating elements may comprise electrically resistive
traces in the ceramic material.
[0024] The heating elements may be chemically bonded to the ceramic
material in a sintered structure.
[0025] The coefficient of thermal expansion of the ceramic material
may be substantially equal to the coefficient of thermal expansion
of the heating elements.
[0026] The heating elements may comprise Tungsten and the ceramic
material may comprise Aluminium Nitride Ceramic.
[0027] The heating elements may be printed to the substrate.
[0028] The heating elements may be arranged to heat the ceramic
material to a temperature sufficient to volatilize at least one
component of smokeable material located in a heating chamber
adjacent the ceramic material.
[0029] The heating elements may be located inside the ceramic
material.
[0030] Layers of the heating elements may be interconnected by
heating element vias through the ceramic material.
[0031] According to the invention, there is also provided an
apparatus comprising a heater arranged to heat smokeable material,
wherein the heater comprises a substrate and at least one heating
element located inside the substrate so as to heat the substrate to
cause the substrate to volatilize at least one component of the
smokeable material for inhalation.
[0032] The heater may comprise a thermal expansion-matching
structure.
[0033] The coefficient of thermal expansion of the heating element
may be substantially equal to the coefficient of thermal expansion
of the substrate.
[0034] The heating element and the substrate may be sintered to
form a chemically bonded structure.
[0035] The substrate may comprise a ceramics material and the
heating element may comprise an electrically resistive trace
material.
[0036] The substrate may be proximal a smokeable material heating
chamber configured to contain the body of smokeable material during
heating.
[0037] The apparatus may comprise a plurality of the heating
elements arranged in layers inside the substrate.
[0038] The layers of heating elements may be interconnected by
heating element vias through the substrate.
[0039] The apparatus may be configured to heat the smokeable
material to a smokeable material volatilizing temperature of at
least 120 degrees Celsius.
[0040] The apparatus may be configured to heat the smokeable
material to a smokeable material volatilizing temperature of
between 120 degrees Celsius and 250 degrees Celsius.
[0041] The apparatus may be configured to heat the smokeable
material to a smokeable material volatilizing temperature of
between 130 degrees Celsius and 180 degrees Celsius.
[0042] The invention may facilitate use of at least one printed
heating element to heat a substrate to a smokeable material
volatilizing temperature and thereby cause the substrate to
volatilize at least one component of smokeable material for
inhalation.
[0043] The invention may facilitate use of a heater comprising a
substrate and a heating element with substantially equal
coefficients of thermal expansion to heat smokeable material to
volatilize at least one component of the smokeable material for
inhalation.
[0044] The invention may facilitate use of a heater comprising a
multiply layered structure of ceramic material and electrically
resistive heating elements to heat smokeable material to volatilize
at least one component of the smokeable material for
inhalation.
[0045] The invention may facilitate use of a heater comprising a
substrate and at least one heating element located inside the
substrate to heat the substrate and cause the substrate to
volatilize at least one component of smokeable material for
inhalation.
[0046] According to the invention, there is provided a method of
heating smokeable material, comprising heating a substrate to a
smokeable material volatilizing temperature using at least one
printed heating element arranged to heat the substrate and causing
the heated substrate to volatilize at least one component of
smokeable material for inhalation.
[0047] According to the invention, there is provided a method of
heating smokeable material, comprising heating a substrate to a
smokeable material volatilizing temperature using at least one
heating element located inside the substrate and causing the heated
substrate to volatilize at least one component of smokeable
material for inhalation.
[0048] For exemplary purposes only, embodiments of the invention
are described below with reference to the accompanying figures in
which:
BRIEF DESCRIPTION OF THE FIGURES
[0049] FIG. 1 is a schematic illustration of layers of a smokeable
material heater comprising a substrate and heating elements
interconnected by vias between the layers;
[0050] FIG. 2 is a schematic, cross sectional illustration of an
apparatus configured to heat smokeable material to release aromatic
compounds and/or nicotine from the smokeable material;
[0051] FIG. 3 is a perspective, partially cut-away illustration of
an apparatus configured to heat smokeable material to release
aromatic compounds and/or nicotine from the smokeable material;
[0052] FIG. 4 is a perspective, partially cut-away illustration of
an apparatus configured to heat smokeable material, in which the
smokeable material is provided around an elongate heater divided
into radial heating sections;
[0053] FIG. 5 is an exploded, partially cut-away view of an
apparatus configured to heat smokeable material, in which the
smokeable material is provided around an elongate heater divided
into radial heating sections;
[0054] FIG. 6 is a flow diagram showing a method of activating
heating regions and opening and closing heating chamber valves
during puffing;
[0055] FIG. 7 is a schematic illustration of a gaseous flow through
an apparatus configured to heat smokeable material;
[0056] FIG. 8 is a graphical illustration of a heating pattern
which can be used to heat smokeable material using a heater;
[0057] FIG. 9 is a schematic illustration of a smokeable material
compressor configured to compress smokeable material during
heating;
[0058] FIG. 10 is a schematic illustration of a smokeable material
expander configured to expand smokeable material during
puffing;
[0059] FIG. 11 is a flow diagram showing a method of compressing
smokeable material during heating and expanding the smokeable
material for puffing;
[0060] FIG. 12 is a schematic, cross-sectional illustration of a
section of vacuum insulation configured to insulate heated
smokeable material from heat loss;
[0061] FIG. 13 is another schematic, cross-sectional illustration
of a section of vacuum insulation configured to insulate heated
smokeable material from heat loss;
[0062] FIG. 14 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;
[0063] FIG. 15 is a schematic, cross-sectional illustration of a
heat shield and a heat-transparent window which are moveable
relative to a body of smokeable material to selectively allow
thermal energy to be transmitted to different sections of the
smokeable material through the window;
[0064] FIG. 16 is schematic, cross sectional illustration of part
of an apparatus configured to heat smokeable material, in which a
heating chamber is hermetically sealable by check valves; and
[0065] FIG. 17 is a schematic, cross sectional illustration of a
partial section of deep-vacuum insulation configured to thermally
insulate an apparatus configured to heat smokeable material.
DETAILED DESCRIPTION
[0066] As used herein, the term `smokeable 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.
[0067] An apparatus 1 for heating smokeable 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. It will be appreciated that, additionally or
alternatively to the battery, the energy source 2 could comprise
other types of source 2 such as one or more fuel cells and/or
another non-battery sources of electricity. The heating chamber 4
is configured to receive smokeable material 5 so that the smokeable
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 smokeable material 5
therein. Heat from the heater 3 heats the smokeable material 5 to
volatilize aromatic compounds and nicotine in the smokeable
material 5 without burning the smokeable material 5. The smokeable
material 5 may comprise a tobacco blend. A mouthpiece 6 is provided
through which a user of the apparatus 1 can inhale the volatilized
compounds during use of the apparatus 1.
[0068] A housing 7 may contain components of the apparatus 1 such
as the energy source 2 and heater 3. As shown schematically in FIG.
2, 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 may extend along the
longitudinal axis of the housing 7. For example, as shown in FIG.
2, the energy source 2 and heater 3 can be aligned along the
central longitudinal axis of the housing 7 in a substantially
end-to-end arrangement so that an end face of the energy source 2
substantially faces an end face of the heater 3. The mouthpiece 6
may be located at the second end 9 of the housing 7, adjacent the
heating chamber 4 and smokeable material 5.
[0069] The length of the housing 7 may be approximately 130 mm. An
example length of the energy source 2 is approximately 59 mm. The
length of the heater 3 and heating region 4 may be approximately 50
mm. The depth, for example the diameter, of the heating chamber 4
may be between approximately 5 mm and approximately 15 mm, such as
between approximately 8 mm and approximately 10 mm. The diameter of
the energy source 2 may be between approximately 10.0 mm and
approximately 15.0 mm, such as 14.6 mm. The diameter of the housing
7 may be between approximately 11 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. Dimensions other than those given above could
alternatively be used.
[0070] The housing 7 is suitable for being gripped by a user during
use of the apparatus 1 so that the user can inhale volatilized
smokeable material compounds from the mouthpiece 6 of the apparatus
1.
[0071] 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.
[0072] The heater 3 may comprise a printed heater 3. For example,
the heater 3 may comprise a substrate 3a and one or more heating
elements 3b which may be printed onto or into the substrate 3a. As
described below, the heating elements 3b may be configured to heat
the substrate 3a at a rapid rate so that the temperature of the
substrate 3a substantially matches the temperature of the heating
elements 3b during heating of the smokeable material 5.
[0073] The substrate 3a may comprise a ceramics material, such as
Aluminium Nitride Ceramic, and the heating elements 3b may comprise
electrically resistive trace elements 3b which are heated by
electrical currents flowing in the elements 3b. For example, the
heating elements 3b may comprise an electrically resistive metal
such as Tungsten. The currents in the heating elements 3b may be
caused by an electromotive force supplied by the energy source 2,
which is electrically coupled to the heater 3.
[0074] The heating elements 3b are arranged in or on the substrate
material 3a so as to heat the substrate 3a. As mentioned above, the
arrangement of the heating elements 3b in or on the substrate 3a
may be so as to heat the substrate 3a to approximately the same
temperature as the heating elements 3b.
[0075] The substrate 3a may be heated by the heating elements 3b to
a volatilizing temperature of the smokeable material 5 so that heat
from the heated substrate 3a causes components of the smokeable
material 5 to be volatilized for inhalation through the mouthpiece
6. Therefore, smokeable material 5 in the heating region 4 may be
heated by both the heating elements 3b and the heated substrate 3a.
The rate at which the temperature of the substrate 3a increases
during heating may be substantially the same as the rate at which
the temperature of the heating elements 3b increase. Therefore, the
temperature of the heating elements 3b and the substrate 3a may be
approximately equal during heating of the smokeable material 5.
[0076] The arrangement of the heater 3 may be such that the
peripheral surfaces of the heater 3 principally comprise those of
the heated substrate 3a and, as such, the smokeable material 5 may
be heated principally by heat emitted from the heated substrate 3a
rather than being heated directly by the heating elements 3b. For
example, as described below and shown schematically in FIG. 1, the
heating elements 3b may be located principally or entirely inside
the substrate 3a and may comprise a plurality of distinct heating
layers of heating elements 3b separated by layers of substrate
3a.
[0077] The coefficient of thermal expansion of the heating elements
3b may be matched to the coefficient of thermal expansion of the
substrate 3a. In particular, the value of the coefficient of
thermal expansion of the heating elements 3b may be substantially
equal to the value of the coefficient of thermal expansion of the
substrate 3a. The heating elements 3b and substrate 3a may
therefore together form an expansion-matching heater structure
3.
[0078] The matched thermal expansion coefficients of the substrate
3a and heating elements 3b means that thermal expansion of the
heating elements 3b is matched by a corresponding expansion in the
substrate 3a. Similarly, thermal contraction of the heating
elements 3b is matched by a corresponding contraction in the
substrate 3a. The expansion-matched nature of structure means that
the heater 3 as a whole expands/contracts at substantially the same
rate and by the same amount across the entire heater structure
during heating/cooling. The expansion and contraction stresses on
the heater structure 3 are small and the heater can be caused to
undergo rapid, significant and frequent temperature transitions
without placing significant material stress on the heater structure
3.
[0079] The substrate 3a and the heating elements 3b may be
chemically bonded together in the heater structure 3. For example,
the chemical bonds between the substrate 3a and the heating
elements 3b may be formed during a sintering process, in which the
substrate 3a and the heating elements 3b are fused together under
the application of heat to create a solid heater structure 3.
[0080] More specifically, the chemically bonded heater structure 3
may be manufactured by initially applying liquid heating element
material 3b to one or more surfaces of the substrate material 3a,
layering the substrate material 3a with the heating element
material 3b and sintering the layered assembly to form the bonded
heater structure 3. This is illustrated schematically in FIG.
1.
[0081] Application of the liquid heating element material 3b can,
for example, be carried out by printing the liquid material 3b onto
the substrate material 3a. The application of the liquid heating
element 3b onto the substrate 3a may be extremely precise so as to
achieve very low tolerances, for example in the order of
micrometres or nanometres, in the location of the heating element
material 3b on the substrate 3a and thereby cause the heating
elements 3b to form in very specific desired regions of the
substrate 3a. A suitable printing process is to use a screen
printer to print the liquid 3b, which may be in the form of an ink,
onto the substrate material 3a.
[0082] The substrate material 3a may comprise suitable binders
and/or plasticizers which aid with the formation of the layered
heater structure 3 before the formation of chemical bonds during
sintering. Additionally or alternatively, the liquid heating
element material 3b may comprise suitable binders and/or
plasticizers. These may be of the same composition as the binders
and/or plasticizers comprised in the substrate material 3a.
[0083] The substrate material 3a onto which the heating element
material 3b is applied may comprise pre-sintered layers of
substrate 3a, such as pre-sintered sections of ceramic tape, which
are built up on top of one another to form a layered structure
comprising both the substrate 3a and the heating element material
3b. One or more vias may be formed in the layers of substrate
material 3a so that the liquid heating material 3b fills the vias
and, ultimately, forms interconnections between the layers of
heating elements 3b in the heater 3. In particular, each layer of
heating elements 3b may be interconnected to one or more other
distinct layers of heating elements 3b by sections of heating
element 3b which pass through the vias in the substrate 3a.
[0084] The vias may be formed by any suitable process. For example,
the vias may be formed by punching holes in the individual layers
of substrate 3a before the layers of substrate 3a are layered on
top of one another in the heater structure 3. The holes in the
layers of substrate 3a may be aligned in the layered structure so
that interconnections between a plurality of layers of heating
elements 3b are created during sintering. The vias formed between
the layers 3b may be of any suitable shape, including
three-dimensional shapes.
[0085] If desired, a plurality of electrical circuits can be
printed onto the substrate 3a in order to provide control signals
or measurement signals to/from a controller 12 of the apparatus 1.
For example, temperature measurement circuits, which may
incorporate one or more Resistance Temperature Detectors (RTD), can
be printed onto, adjacent or underneath the heater elements 3b, or
elsewhere on the substrate 3a, so that the temperature of the
heater 3 can be monitored and adjusted by the controller 12 to
obtain desired volatilizing or pre-volatilizing temperatures in the
smokeable material 5.
[0086] Before the assembly of substrate layers 3a and heating
element material 3b is sintered to create the chemical bonds and
cohesive nature of the heater 3 referred to above, the assembly may
be de-bound of the binders and/or plasticizers referred to
previously. The chemical bonds and the matched thermal expansion
coefficients create a robust heater structure 3, which can be
repeatedly re-used to heat and volatilize newly-loaded smokeable
material 5 in the heating region 4.
[0087] The heater 3 can be manufactured into any suitable shape
using the layering technique described above. For example, the
heater 3 may comprise a substantially hollow cylinder located
around the smokeable material heating region 4 so that heat is
emitted by the heater 3 in a radially inward direction. An example
of this is described below in relation to FIG. 2. Alternatively,
the smokeable material heating region 4 may be located around the
heater 3. An example is a co-axial arrangement in which the heater
3 emits heat in a radially outward direction into the heating
region 4, although other shapes are also possible as will be
evident from the discussion below.
[0088] A specific example of an expansion matched, chemically
bonded heater structure 3 is one in which the heating substrate 3a
comprises pre-sintered Aluminium Nitride Ceramic tape and the
heating element material 3b comprises Tungsten-containing ink which
is screen printed onto the ceramics tape 3a. Once the ceramics tape
3a has been printed with the heating element material 3b and holes
have been created to form the vias referred to above, the ceramics
tape 3a is layered so as to form a structure containing internal
layers of heating element material 3b connected together by vias in
the tape 3a. The assembly is then sintered to form a cohesive and
chemically-bonded heater 3. During activation of the heater 3, the
Aluminium Nitride substrate 3a and Tungsten heating elements 3b
expand and contract at a rate of approximately 4.5 parts per
million per degree centigrade and thus the heater structure 3 as a
whole expands and contracts without placing stress on any
particular part of the structure 3.
[0089] The thickness of the heater 3 may be small, such as less
than 2 mm or less than 1 mm, which can contribute towards reducing
the overall dimensions of the apparatus 1 compared to the use of
other types of heaters. For example, the heater 3 may have a
thickness of between approximately 0.1 mm and 2.0 mm, such as
between approximately 0.3 mm and approximately 1.0 mm, although
heaters 3 with larger thicknesses such as those up to 6.5 mm are
equally possible.
[0090] The heater 3 can be operated over a wide range of power
outputs in order to heat and maintain the smokeable material 5 in a
desired temperature range. For example, the power output of the
heater 3 may be in the range of zero to approximately 2000
watts/in.sup.2 and may be controllable by the controller 12 of the
apparatus 1 so that the temperature of the smokeable material 5 is
maintained or adjusted into the desired temperature range. The
controller 12 may adjust the power output of the heater 3 based on
measurements of temperature inside the heater 3, at the peripheral
surfaces of the heater 3 and/or inside the smokeable material 5,
using the temperature measurement circuits referred to above.
[0091] The controller 12 may cause the heater 3, or distinct
regions 10 of the heater 3, to cycle between predetermined set
temperatures for predetermined periods of time or may vary the
temperature of the heater 3 and/or separate regions 10 of the
heater 3 in accordance with a heating regime. The controller 12 and
examples of suitable heating regimes are described in more detail
below. The heater 3 has a low mass and therefore its use can help
to reduce the overall mass of the apparatus 1.
[0092] As shown in FIG. 2 and referred to briefly above, the heater
3 may 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 smokeable material 5. This may be achieved by activating
heating elements 3b located in particular regions 10 of the heater
3 at different times. The heating regions 10 may be arranged in the
heater 3 in any geometric arrangement. However, in the example
shown in FIG. 2, 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 smokeable material 5.
[0093] For example, referring to FIG. 2, the heater 3 may comprise
a plurality of axially aligned heating regions 10 in a
substantially elongate arrangement. The regions 10 may each
comprise an individual section of the heater 3, such as an
independently temperature-controllable section of the bonded
substrate 3a and heating elements 3b structure 3 described above.
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.
[0094] Referring to FIG. 2, each heating region 10 may comprise a
hollow heating cylinder 10, which may be a ring 10, having a finite
length which is significantly less than the length of the heater 3
as a whole. The arrangement of axially aligned heating regions 10
define the exterior of the heating chamber 4 and are configured to
heat smokeable material 5 located in the heating chamber 4. As
mentioned previously, the heat is applied inwardly, predominately
towards the central longitudinal axis of the heating chamber 4. The
heating regions 10 are arranged with their radial, or otherwise
transverse, surfaces facing one another along the length of the
heater 3. The transverse surfaces of each heating region 10 may
optionally be separated from the transverse surfaces of their
neighbouring heating region(s) 10 by thermal insulation 18, as
shown in FIG. 2 and described below, or may connected and/or
contiguous with their neighbouring heating region(s) 10.
[0095] As shown in FIGS. 2 and 3, the heater 3 may alternatively be
located in a central region of the housing 7 and the heating
chamber 4 and smokeable material 5 may be located around the
longitudinal surface of the heater 3. In this arrangement, thermal
energy emitted by the heater 3 travels outwards from the
longitudinal surface of the heater 3 into the heating chamber 4 and
the smokeable material 5.
[0096] The heating regions 10 may each comprise an individual
section of the heater 3. As shown in FIGS. 1 to 4, 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. However, other configurations of heater 3 could
alternatively be used and so the use of cylindrical sections of
heater 3 is not required. The heating regions 10 may be arranged
with their transverse surfaces facing one another along the length
of the heater 3. The transverse surfaces of each region 10 may
touch the transverse surfaces of its neighbouring regions 10.
Alternatively, a heat insulating or heat reflecting layer may be
present between the transverse surfaces of the regions 10 so that
thermal energy emitted from each one of the regions 10 does not
substantially heat the neighbouring regions 10 and instead travels
predominately into the heating chamber 4 and smokeable material 5.
Each heating region 10 may have substantially the same dimensions
as the other regions 10.
[0097] In this way, when a particular one of the heating regions 10
is activated, it supplies thermal energy to the smokeable material
5 located adjacent, for example radially adjacent, the heating
region 10 without substantially heating the remainder of the
smokeable material 5. Referring to FIG. 3, the heated region of
smokeable material 5 may comprise a ring of smokeable material 5
located around the heating region 10 which has been activated. The
smokeable material 5 can therefore be heated in independent
sections, for example rings or substantially solid cylinders, where
each section corresponds to smokeable material 5 located directly
adjacent a particular one of the heating regions 10 and has a mass
and volume which is significantly less than the body of smokeable
material 5 as a whole.
[0098] Additionally or alternatively, 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. The heating regions 10 may be of different
lengths, or may be of substantially the same length so that each
extends along substantially the whole length of the heater 3.
[0099] The heated sections of smokeable material 5 may comprise
longitudinal sections of smokeable material 5 which lie parallel
and directly adjacent to the longitudinal heating regions 10.
Therefore, as explained previously, the smokeable material 5 can be
heated in independent sections.
[0100] As will be described further below, the heating regions 10
can each be individually and selectively activated.
[0101] The smokeable material 5 may be comprised in a cartridge 11
which can be inserted into the heating chamber 4. For example, as
shown in FIG. 2, the cartridge 11 can comprise a substantially
solid body of smokeable material 5 such as a cylinder which fits
into a recess of the heater 3. In this configuration, the external
surface of the smokeable material body faces the heater 3.
Alternatively, as shown in FIG. 3, the cartridge 11 can comprise a
smokeable material tube 11 which can be inserted around the heater
3 so that the internal surface of the smokeable material tube 11
faces the longitudinal surface of the heater 3. The smokeable
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 or otherwise transverse dimension 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.
[0102] 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 an 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 smokeable material 5. Alternatively, a
section of the housing 7 at the second end 9 is removable from the
apparatus 1 so that the smokeable material 5 can be inserted into
the heating chamber 4. The apparatus 1 may optionally be equipped
with a user-operable smokeable material ejection unit, such as an
internal mechanism configured to slide used smokeable material 5
off and/or away from the heater 3. The used smokeable 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.
[0103] As mentioned previously, 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 smokeable 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 smokeable 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. 5.
[0104] 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.
[0105] Referring to FIG. 6, 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 smokeable 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 S4, the valves 24 are
closed. These valves 24 are described in more detail below with
respect to FIG. 30. In fifth S5, sixth S6, seventh S7 and eighth S8
steps, a second section of smokeable 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 smokeable 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 smokeable 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
smokeable material 5 may correspond to the number of puffs for
which the cartridge 11 is intended to be used. Alternatively, each
independently heatable smokeable 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
smokeable material 5 is heated only after a plurality of puffs have
been taken whilst heating the previous smokeable material
section.
[0106] 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 smokeable
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.
6 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 smokeable 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.
[0107] 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 smokeable 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/or lighter energy
source 2 can be installed in the apparatus 1.
[0108] 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 smokeable material 5, to be partially
activated so that it heats up in preparation to volatilize
components of the smokeable material 5. The partial activation does
not heat the smokeable material 5 to a sufficient temperature to
volatilize nicotine. A suitable temperature could be less than
120.degree. C., such as approximately 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 smokeable material 5 further in order to rapidly volatilize the
nicotine and other aromatic compounds for inhalation by the user.
If the smokeable material 5 comprises tobacco, a suitable
temperature for volatilizing the nicotine and other aromatic
compounds may be above 120.degree. C., such between 150.degree. C.
and 250.degree. C. or between 130.degree. C. and 180.degree. C.
Therefore, examples of full activation temperatures include
180.degree. C. and 250.degree. C. A super-capacitor can optionally
be used to provide the peak current used to heat the smokeable
material 5 to the volatilization temperature. An example of a
suitable heating pattern is shown in FIG. 8, in which the peaks may
respectively represent the full activation of different heating
regions 10. As can be seen, the smokeable material 5 is maintained
at the volatilization temperature for the approximate period of the
puff which, in this example, is two seconds.
[0109] Three example operational modes of the heater 3 are
described below.
[0110] 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.
[0111] 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 volatilized from the smokeable 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 smokeable material 10
located adjacent the partially activated regions 10 is not heated
to a temperature sufficient to volatilize components of the
smokeable material 5.
[0112] 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 volatilized
from the smokeable material 5 in the heating chamber 4.
[0113] The apparatus 1 may comprise a heat shield 100, which is
located between the heater 3 and the heating chamber 4/ smokeable
material 5. The heat shield 100 is configured to substantially
prevent thermal energy from flowing through the heat shield 100 and
therefore can be used to selectively prevent the smokeable material
5 from being heated even when the heater 3 is activated and
emitting thermal energy. Referring to FIG. 15, the heat shield 100
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 smokeable material 5 as previously described with
reference to FIG. 2, the heat shield 100 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 100 may additionally or alternatively comprise a
heat-insulating layer configured to insulate the heater 3 from the
smokeable material 5.
[0114] The heat shield 100 comprises a substantially
heat-transparent window 101 which allows thermal energy to
propagate through the window 101 and into the heating chamber 4 and
smokeable material 5. Therefore, the section of smokeable material
5 which is aligned with the window 101 is heated whilst the
remainder of the smokeable material 5 is not. The heat shield 100
and window 101 may be rotatable or otherwise moveable with respect
the smokeable material 5 so that different sections of the
smokeable material 5 can be selectively and individually heated by
rotating or moving the heat shield 100 and window 101. 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 100 and window 101 may be rotated or otherwise
moved incrementally in response to a signal from the puff detector
13. Additionally or alternatively, the heat shield 100 and window
101 may be rotated or otherwise moved incrementally in response to
a predetermined heating period having elapsed. Movement or rotation
of the heat shield 100 and window 101 may be controlled by
electronic signals from the controller 12. The relative rotation or
other movement of the heat shield 100/ window 101 and smokeable
material 5 may be driven by a stepper motor 3c under the control of
the controller 12. This is illustrated in FIG. 15. Alternatively,
the heat shield 100 and window 101 may be manually rotated using a
user control such as an actuator on the housing 7. The heat shield
100 does not need to be cylindrical and may optionally comprise one
or more suitably positioned longitudinally extending elements and
or/plates.
[0115] It will be appreciated that a similar result can be obtained
by rotating or moving the smokeable material 5 relative to the
heater 3, heat shield 100 and window 101. 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
100 can be applied instead to movement of the heating chamber 4
relative to the heat shield 100.
[0116] The heat shield 100 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 101. 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 smokeable material 5 to be heated.
Alternatively, the heat shield 100 and window 101 may comprise a
separate shield 3a which is rotatable or otherwise moveable
relative to both the heater 3 and the smokeable material 5 under
the control of the controller 12 or other user controls.
[0117] The apparatus 1 may comprise air inlets 14 which allow
external air to be drawn into the housing 7 and through the heated
smokeable material 5 during puffing. The air inlets 14 may comprise
apertures 14 in the housing 7 and may be located upstream from the
smokeable material 5 and heating chamber 4 towards the first end 8
of the housing 7. This is shown in FIG. 2. Another example is shown
in FIG. 7. Air drawn in through the inlets 14 travels through the
heated smokeable material 5 and therein is enriched with smokeable
material vapours, such as aroma vapours, before being inhaled by
the user at the mouthpiece 6. Optionally, as shown in FIG. 7, the
apparatus 1 may comprise a heat exchanger 15 configured to warm the
air before it enters the smokeable 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
smokeable material 5.
[0118] The apparatus 1 may comprise a smokeable material compressor
16 configured to cause the smokeable material 5 to compress upon
activation of the compressor 16. The apparatus 1 can also comprise
a smokeable material expander 17 configured to cause the smokeable
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 smokeable 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 smokeable
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 smokeable material 5 as
required.
[0119] The compressor 16 is principally configured to compress the
smokeable material 5 and thereby increase its density during
heating. Compression of the smokeable material increases the
thermal conductivity of the body of smokeable material 5 and
therefore provides a more rapid heating and consequent rapid
volatilization of nicotine and other aromatic compounds. This
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
smokeable material 5 for a 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
smokeable 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 smokeable material 5 reaching a
predetermined threshold temperature. A suitable threshold
temperature may be in the range of approximately 120.degree. C. to
250.degree. C., or one of the other ranges discussed previously,
and may be user selectable. A temperature sensor may be used to
detect the temperature of the smokeable material 5.
[0120] The expander 17 is principally configured to expand the
smokeable material 5 and thereby decrease its density during
puffing. The arrangement of smokeable material 5 in the heating
chamber 4 becomes more loose when the smokeable material 5 has been
expanded and this aids the gaseous flow, for example air from the
inlets 14, through the smokeable 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 smokeable material 5 immediately
following the compression period referred to above so that air can
be drawn more freely through the smokeable 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 smokeable material 5
has been heated and that puffing can commence.
[0121] Referring to FIGS. 8 and 9, the compressor 16 and expander
17 may comprise a spring-actuated driving rod which is configured
to compress the smokeable material 5 in the heating chamber 4 when
the spring is released from compression. This is schematically
illustrated in FIGS. 8 and 9, 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 smokeable 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 smokeable material 5 under
the control of the controller 12. A method of compressing and
expanding the smokeable material 5 is shown in FIG. 11. The method
comprises a first step P1 of compressing the smokeable material 5
in its heating chamber 4, a second step P2 of heating the
compressed smokeable material 5, a third step P3 of detecting a
threshold temperature in the smokeable material 5, a fourth step S4
of expanding the smokeable material 5, for example by releasing the
compression force, and a fifth step S5 of allowing external air to
enter the smokeable material heating chamber 4, for example by
opening hermetically sealable inlet and outlet valves 24.
[0122] The heater 3 may be integrated with the thermal insulation
18 mentioned previously. For example, referring to FIG. 2, the
thermal insulation 18 may comprise a substantially elongate, hollow
body, such as a substantially cylindrical tube of insulation 18,
which is located co-axially around the heating chamber 4 and into
which the heating regions 10 are integrally located. The thermal
insulation 18 may comprise a layer in which recesses are provided
in the inwardly facing surface profile 21. Heating regions 10 are
located in these recesses so that the heating regions 10 face the
smokeable material 5 in the heating chamber 4. The surfaces of the
heating regions 10 which face the heating chamber 4 may be flush
with the inside surface 21 of the thermal insulation 18 in regions
of the insulation 18 which are not recessed.
[0123] The integration of the heater 3 with the thermal insulation
18 means that the heating regions 10 are substantially surrounded
by the insulation 18 on all sides of the heating regions 10 other
than those which face inwardly towards the smokeable material
heating chamber 4. As such, heat emitted by the heater 3 is
concentrated in the smokeable material 5 and does not dissipate
into other parts of the apparatus 1 or into the atmosphere outside
the housing 7.
[0124] Integration of the heater 3 with the thermal insulation 18
may also reduce the thickness of the combination of heater 3 and
thermal insulation 18. This can allow the diameter of the apparatus
1, in particular the external diameter of the housing 7, to be
further reduced. Alternatively, the reduction in thickness provided
by the integration of the heater 3 with the thermal insulation 18
can allow a wider smokeable material heating chamber 4 to be
accommodated in the apparatus 1, or the introduction of further
components, without any increase in the overall width of the
housing 7.
[0125] Alternatively, the heater 3 may be located adjacent the
insulation 18 rather than being integrated into it. For example, if
the heater 3 is located externally of the heating chamber 4 as
shown in FIG. 2, the insulation 18 may be located around the
outside of the heater 3 so that the inwardly-facing surface 21 of
the insulation faces the heater 3. If the heater 3 is located
internally of the heating chamber 4, the heater 3 may be located
around the outwardly-facing surface 22 of the insulation 18.
[0126] Optionally, a barrier may be present between the heater 3
and the insulation 18. For example, a layer of stainless steel may
be present between the heater 3 and the insulation 18. The barrier
may comprise a stainless steel tube which fits between the heater 3
and the insulation 18. The thickness of the barrier may be small so
as not to substantially increase the dimensions of the apparatus.
An example thickness is between approximately 0.1 mm and 1.0
mm.
[0127] Additionally, a heat reflecting layer may be present between
the transverse surfaces of the heating regions 10. The arrangement
of the heating regions 10 relative to each other may be such that
thermal energy emitted from each one of the heating regions 10 does
not substantially heat the neighbouring heating regions 10 and
instead travels predominately inwardly from the circumferential
surface of the heating region 10 into the heating chamber 4 and
smokeable material 5. Each heating region 10 may have substantially
the same dimensions as the other regions 10.
[0128] The heater 3 may be bonded or otherwise secured in the
apparatus 1 using pressure sensitive adhesive. For example, the
heater 3 may be adhered to the insulation 18 or barrier referred to
above using pressure sensitive adhesive. The heater 3 may
alternatively be adhered to the cartridge 11 or an exterior surface
of the smokeable material heating chamber 4.
[0129] As an alternative to the use of pressure sensitive adhesive,
the heater 3 may be secured in position in the apparatus 1 using
self-fusing tape or by clamps which clamp the heater 3 in place.
All of these methods provide a secure fixing for the heater 3 and
allow effective heat transfer from the heater 3 to the smokeable
material 5. Other types of fixing are also possible.
[0130] The thermal insulation 18, which is provided between the
smokeable material 5 and an external surface 19 of the housing 7,
as described above, reduces heat loss from the apparatus 1 and
therefore improves the efficiency with which the smokeable material
5 is heated. For example, referring to FIG. 2, 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 smokeable
material 5. This is shown in FIG. 2. It will be appreciated that
the insulation 18 could also be comprised as part of the smokeable
material cartridge 11, in which it would be located co-axially
around the outside of the smokeable material 5.
[0131] Referring to FIG. 12, 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/mK. 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 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.
[0132] As shown in FIG. 12, the wall 19 may comprise an
inwardly-facing section 21 and an outwardly-facing section 22. The
inwardly-facing section 21 substantially faces the smokeable
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.
[0133] 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.
[0134] 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.
[0135] 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. 17,
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. 17 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.
[0136] 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.
[0137] 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.
[0138] 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.
[0139] Referring to the schematic illustration in FIG. 13, 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 smokeable material 5 is
heated.
[0140] 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. 14. 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
smokeable 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 smokeable material 5 are
not present.
[0141] Referring to FIG. 16, 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 smokeable
material flavours from exiting the chamber 4. The inlet and outlet
valves 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
volatilized 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 smokeable 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.
[0142] The mass of the smokeable 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 smokeable
material 5 is heated may be user controllable, for example to any
temperature within the temperature range of 120.degree. C. to
250.degree. C. as previously described. The mass of the apparatus 1
as a whole may be in the range of 70 to 125 g, although the mass of
the apparatus 1 can be lower when incorporating the type of heater
3 described above and/or deep-vacuum insulation 18. 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
smokeable material 5 for a single cartridge 11.
[0143] It will be appreciated that any of the alternatives
described above can be used singly or in combination.
[0144] 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.
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