U.S. patent application number 11/528274 was filed with the patent office on 2007-05-10 for electrical smoking system.
This patent application is currently assigned to Philip Morris USA Inc.. Invention is credited to John M. Adams, James D. JR. Baggett, William J. Crowe, John R. JR. Hairfield, John R. Hearn, Steven J. Larson, Robert E. Lee, Robert L. Ripley, Brett W. Stevenson, Susan E. Wrenn, Zuyin Yang.
Application Number | 20070102013 11/528274 |
Document ID | / |
Family ID | 37943184 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070102013 |
Kind Code |
A1 |
Adams; John M. ; et
al. |
May 10, 2007 |
Electrical smoking system
Abstract
A tobacco mass is heated to a temperature of about 150.degree.
to about 220.degree. C. to release flavorful tobacco volatiles,
which are entrained in air passing through the tobacco mass, and
condensed to form an inhalable aerosol. The tobacco mass may have a
rotationally symmetric shape, with at least part of its surface in
heat transfer relationship with a heater. The heater may be an
external shell, an internal rod, or a plate. A shell can enclose
the heater and tobacco mass and define a preheating chamber for
inflowing air. A mouthpiece, with or without a filter, may be
arranged in fluid communication with the tobacco mass to direct the
aerosol from the heating system.
Inventors: |
Adams; John M.;
(Mechanicsville, VA) ; Crowe; William J.;
(Chester, VA) ; Hearn; John R.; (Midlothian,
VA) ; Lee; Robert E.; (Richmond, VA) ;
Stevenson; Brett W.; (Richmond, VA) ; Yang;
Zuyin; (Midlothian, VA) ; Baggett; James D. JR.;
(Richmond, VA) ; Hairfield; John R. JR.; (Chester,
VA) ; Larson; Steven J.; (Richmond, VA) ;
Ripley; Robert L.; (Midlothian, VA) ; Wrenn; Susan
E.; (Chesterfield, VA) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Philip Morris USA Inc.
Richmond
VA
|
Family ID: |
37943184 |
Appl. No.: |
11/528274 |
Filed: |
September 28, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60722036 |
Sep 30, 2005 |
|
|
|
Current U.S.
Class: |
131/273 ;
131/185 |
Current CPC
Class: |
A24F 40/485 20200101;
A24F 40/20 20200101; A24D 1/20 20200101; A24F 40/46 20200101 |
Class at
Publication: |
131/273 ;
131/185 |
International
Class: |
A24F 3/00 20060101
A24F003/00 |
Claims
1. A combustionless tobacco smoking system comprising: a tobacco
mass; and heating apparatus, substantially enclosing the tobacco
mass, electrically operated, operable to heat the tobacco mass to a
temperature in the range of 150 to 220.degree. C., defining a heat
transfer channel through which air is directed.
2. The combustionless tobacco smoking system of claim 1 wherein:
(a) the tobacco mass has a rotationally symmetric shape; (b) the
tobacco mass is enclosed in a carrier; and/or (c) at least part of
the surface of the tobacco mass conforms to the heating
apparatus.
3. The combustionless tobacco smoking system of claim 2, wherein:
(a) the tobacco mass has a generally cylindrical shape; (b) the
tobacco mass has a disk shape; or (c) the tobacco mass is generally
toroidal.
4. The combustionless tobacco smoking system of claim 3, wherein:
(a) the cylindrical shape is solid; or (b) the cylindrical shape is
hollow.
5. The combustionless tobacco smoking system of claim 2, wherein:
(a) the carrier is paper; or (b) the carrier is a mesh
material.
6. The combustionless tobacco smoking system of claim 2, wherein:
(a) the heating apparatus includes a substantially cylindrical
heating element; (b) the heater includes a rod, the rod being
received by the tobacco mass; (c) the heater includes a heater
plate; and/or (d) the heater includes an annular plate and a
disk-shaped plate, and wherein the tobacco mass is sandwiched
between the annular plate and the disk-shaped plate.
7. The combustionless tobacco smoking system of claim 6, further
including a shroud which receives the substantially cylindrical
heating element.
8. The combustionless tobacco smoking system of claim 7, wherein
the substantially cylindrical heating element and the shroud define
a preheating chamber for air.
9. The combustionless tobacco smoking system of claim 2, further
including a mouthpiece having an end in fluid communication with
the tobacco mass.
10. The combustionless tobacco smoking system of claim 9, wherein:
(a) the mouthpiece includes a second end having a filter; and/or
(b) the mouthpiece is attached between the tobacco mass and the
heater.
11. The combustionless tobacco smoking system of claim 6, wherein
the heater rod has an end extending from the tobacco mass, and
wherein a heater disk is attached to the heater rod.
12. The combustionless tobacco smoking system of claim 11, wherein
the heater disk includes air passages.
13. The combustionless tobacco smoking system of claim 6, wherein:
(a) the heater plate is generally circular; and/or (b) the heater
plate includes air passages therethrough.
14. The combustionless tobacco smoking system of claim 6, further
including: (a) an insulation plate generally coextensive with the
heater plate; and/or (b) a baffle substantially surrounding the
tobacco mass and operable to direct airflow into the tobacco
mass.
15. The combustionless tobacco smoking system of claim 14, further
including an annular heating plate.
16. The combustionless tobacco smoking system of claim 15, wherein
the baffle and the annular heating plate define a preheating
passage.
17. The combustionless tobacco smoking system of claim 14, further
including a connector tube which defines an airflow passage for air
leaving the smoking system.
18. The combustionless tobacco smoking system of claim 17, further
including a mouthpiece.
19. The combustionless tobacco smoking system of claim 18, wherein
the mouthpiece includes a filter.
20. A method of producing a tobacco aerosol comprising:
establishing a stream of air; contacting a tobacco mass with said
stream of air while heating said tobacco mass to a temperature in
the range of 150 to 220.degree. C., defining a heat transfer
channel through which air is directed.
Description
FIELD OF THE DISCLOSURE
[0001] This disclosure relates generally to tobacco smoking systems
using electrical energy rather than combustion. More particularly,
the smoking system disclosed here generates an aerosol through
conductive and/or convective combustionless heating of tobacco by
an electrical heating source.
SUMMARY
[0002] A quantity of tobacco is placed in contact with a heating
system. Passageways are provided for air to move through the
heating system and the tobacco. The heating system raises the
temperature of the tobacco to the range of about 150 to about
220.degree. C. by direct contact with the tobacco, by convective
heat transfer to the tobacco, and/or by heating the air which in
turn heats the tobacco. The heated tobacco releases volatiles which
subsequently cool to form an aerosol for delivery from the heating
system.
[0003] The tobacco may have a variety of shapes including without
limitation a pillow shape, a generally rotationally symmetric
shape, a generally cylindrical plug, a generally cylindrical shell,
a generally circular disk, a plug shape, a pellet shape, a
cigarette shape, and the like.
[0004] The heating system may also have a variety of
configurations. By way of example, and without limitation, the
heating system may include a heating element such as a generally
cylindrical heated shell with both ends open, a generally
cylindrical heated shell with a closed end, an insertable heating
element, a heated disk, a pair of heated disks, or the like. Such
heating elements may be fabricated from an electrically resistive
material which heats when electrical current passes through it.
Such heating elements may also include either internal or external
heating devices such as wires. Air may pass axially through the
tobacco and the heating system. Alternatively, air may enter the
tobacco radially and exit substantially axially. In addition, the
heating system may be arranged such that air is preliminarily
heated before being directed into the tobacco.
[0005] If desired, a mouthpiece, with or without a filter, may be
used with the heating system both to define a cooling region for
the tobacco volatiles, and to direct the resulting aerosol to the
consumer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The accompanying drawings depict several embodiments of the
electrically heated tobacco smoking system of this disclosure. In
the accompanying drawings, like reference numerals are applied to
like elements.
[0007] FIG. 1 is a cross-sectional view of an electrically heated
tobacco smoking system.
[0008] FIG. 2 is a cross-sectional view of the electrically heated
tobacco smoking system taken along the line 2-2 of FIG. 1.
[0009] FIG. 3 is a cross-sectional view of another embodiment of
the electrically heated tobacco smoking system.
[0010] FIG. 4 is a cross-sectional view taken along the line 4-4 of
FIG. 3.
[0011] FIG. 5 is a cross-sectional view of the electrically heated
smoking system of FIG. 1 including a mouthpiece.
[0012] FIG. 6 is an end view of the electrically heated tobacco
smoking system of FIG. 5.
[0013] FIG. 7 is a cross-sectional view of a third embodiment of
the electrically heated tobacco smoking system.
[0014] FIG. 8 is an end view of the electrically heated tobacco
smoking system of FIG. 7.
[0015] FIG. 9 is a cross-sectional view of an electrically heated
tobacco smoking system using a pillow of tobacco material.
[0016] FIG. 10 is an end view of the electrically heated tobacco
smoking system of FIG. 9.
[0017] FIG. 11 is a cross-sectional view of an electrically heated
tobacco smoking system having radial inflow of air.
[0018] FIG. 12 is an end view of the electrically heated tobacco
smoking system of FIG. 11.
[0019] FIG. 13 is a cross-sectional view of an electrically heated
tobacco smoking system having counter-current heat exchange.
[0020] FIG. 14 is an end view of the electrically heated tobacco
smoking system of FIG. 13.
[0021] FIG. 15 is a cross-sectional view of an electrically heated
tobacco smoking system with a toroidal tobacco mass.
[0022] FIG. 16 is a cross-sectional view taken along line 16-16 of
FIG. 15.
DETAILED DESCRIPTION
[0023] Turning to FIG. 1, an electrically operated tobacco smoking
system 20 according to this disclosure is depicted. The smoking
system 20 includes at least a heating system 22 and a tobacco mass
that may comprise a plug 24 of cut filler tobacco. The heating
system may be an inductively heated arrangement, a resistively
heated arrangement, a radiantly heated arrangement, or a
convectively heated arrangement. Here, resistively heated
arrangements will be described as currently preferred embodiments.
The tobacco plug 24 preferably weighs in the range of 5 to 500 mg.
For single and multiple puff applications, weights in the range of
5 to 150 mg. are more preferable. Weights in the range of 300 to
500 mg. are more preferable where tobacco is to be used on multiple
occasions. The tobacco mass may be made from any type of tobacco,
or from any portion of the tobacco plant including, without
limitation, sheet products, dust, leaf, stem, and combinations
thereof. In the final form, the tobacco mass could involve any type
of common tobacco processing steps including, without limitation,
blending, flavoring, and the like.
[0024] If desired, the tobacco plug 24 may include a paper or mesh
cover or carrier to facilitate handling. When paper is used around
the tobacco plug, the paper substrate may have porosity and weight
selected according to the particular shape of the heating chamber
and the manner in which the tobacco plug 24 is to be used. For
example, where the tobacco plug 24 is replaceable, the paper needs
to have sufficient strength to maintain integrity of the tobacco
plug during handling, removal, and insertion. Moreover, where the
paper covers the principal movement of air through the smoking
system, the paper needs to have sufficient porosity to allow air
movement therethrough. Where a mesh material is selected, mesh
opening should be sized small enough to contain a substantial
majority, if not all, of the cut filler tobacco particles.
[0025] The tobacco mass may also be formed from tobacco particles.
Whether particles or other tobacco cuts are used, the tobacco
itself may function as a binder to hold tobacco pieces in a
preferred shape. If desired, the tobacco used in the system can be
pretreated to enhance flavor generation. Similarly, if desired,
flavorants can be provided on the tobacco surface.
[0026] The tobacco mass may be rotationally symmetric in shape or
configuration. Moreover, the tobacco mass may be generally
cylindrical, disk-like, or generally toroidal. Where a cylindrical
configuration is adopted, it may be solid or shell-like with an
open center. The particular shape of the tobacco mass is preferably
adapted to the shape of the heating apparatus.
[0027] The heating system 22 substantially encloses or surrounds a
substantial portion of the tobacco mass such that at least part of
the surface of the tobacco mass conforms to the heating apparatus.
An actuation system connected with the heating system 22 is
operable to electrically energize the heating system 22. The
actuation system may include a source of electrical energy such as
one or more batteries 37. To preserve battery life and to control
activation of the heating system 22, a suitable switch 38 may be
connected in series with the batteries 37. Depending on the
application, the switch 38 may be a push-button switch, a flow
sensing device, or a puff sensing device. A suitable conductor 36
connects the batteries 37, the switch 38, and the heating system 22
in series.
[0028] The heating system 22 is operable to heat the tobacco mass
to a temperature in the range of about 150.degree. to about
220.degree. C. to release flavorful volatiles without reaching the
tobacco kindling temperature and without generating smoke and/or
ash. Further, the heating system defines a heat transfer channel or
pathway through which air is directed.
[0029] As shown, the heating system 22 may comprise a generally
cylindrical shell having both ends open. As best seen in FIG. 2,
the generally cylindrical shell surrounds the sides of the tobacco
plug 24. The heating system 22 is electrically energized to
generate heat. To that end, the heating system 22 may be connected
to a suitable source of electrical energy, such as, for example,
domestic power grid, portable power generating devices like an
automobile cigarette lighter, batteries, and any other suitable
conventional source. The source of energy must be capable of
delivering heat from the heating system 22 to the tobacco plug 24
so that the tobacco in the plug is raised to a temperature in the
range of about 150.degree. C. to about 220.degree. C. Within this
temperature range, the tobacco releases flavorful volatiles that
produce a satisfying experience while generating little to no
visible smoke.
[0030] The heating system 22 may operate continuously for a period
of time corresponding to the length of time normally used to smoke
a cigarette. Conventionally, that length of time is typically taken
as about 5 to 10 minutes. Alternatively, the heating system 22 may
operate intermittently, on demand, for example in response to puffs
by the system user.
[0031] In use, the heating system 22 is activated, for example, by
a puff sensor or a suitable "on-off" device. Ambient air 26 is
drawn through the open end 28 of the heating system 20 and into the
tobacco plug 24. The heating system 22 closely conforms to the
periphery of the tobacco plug 24 and heats the tobacco plug 24 to
the desired temperature range (about 150.degree. C. to about
220.degree. C.) by conductive and/or convective heat transfer to
release flavorful volatiles from the tobacco. As the ambient air 26
moves through the tobacco plug 24, the air 26 entrains the released
tobacco volatiles and distills those volatiles by cooling them. As
the air with entrained volatiles leaves the second end of the
heating system 22, see arrow 30, exposure to ambient air further
cools the entrained volatiles to form an aerosol 32 which is
delivered from the heating system 22.
[0032] If desired, an aerosol former may be added to the tobacco
plug 24. Suitable aerosol formers include, for example, glycerol,
propylene glycol, triacetin, and the like, as well as mixtures
thereof. Concentrations of aerosol former in the range of about 0
to about 25% by weight can be used. The aerosol formers also
enhance tobacco involvement in the aerosol formation.
[0033] After the tobacco plug 24 has been used, it may be removed
from the heating system 22 and replaced with a fresh plug or
cartridge. The spent tobacco plug 24 may be discarded.
[0034] It will be appreciated by those skilled in the art that the
electric tobacco smoking system described herein provides numerous
advantages. For example, a smaller amount of tobacco is used so
tobacco supplies can be extended. By using less tobacco, the
disposable waste from the smoking experience is also reduced. In
addition, since the heating system releases principally the
flavorful volatiles from the tobacco which may be perceived as more
pleasing than the sidestream aroma resulting from cigarette
combustion.
[0035] The tobacco plug 24 is not subject to actual combustion as
occurs with lit-end smoking articles. Because the electric tobacco
smoking system described here does not have a smoldering coal, it
presents less risk of starting a fire when carelessly handled than
a conventional lit-end cigarette. For the same reason, the smoking
system herein described requires less cleaning as there is
essentially no ash with which to contend. Furthermore, the
disposable waste which does exist has less residual aroma due to
the lack of combustion. Moreover, absence of smoke should obviate
non-smoker objections to second-hand smoke.
[0036] Of course, various other embodiments of the electric tobacco
smoking system are not only possible but also are within the scope
of this disclosure. For example (see FIG. 3), the tobacco plug 24
may be substantially enclosed by the heating system 22. In this
embodiment, the heating system may include a heater 40 that is
received within a generally cylindrical shroud 42. The actuation
system of FIG. 3 is like that of FIG. 1 and includes conductors 36,
batteries 37, and a switch 38.
[0037] To provide one or more channels for air flow around the
heater 40, the heater 40 and/or the shroud 42 may include two or
more radially outwardly extending ribs 44, 46 (see FIG. 4) which
are operable to space the heater 40 from the shroud 42. The ribs
44, 46 may extend longitudinally along the outer surface of the
heater 40. The ribs 44, 46, cooperate with the shroud 42 and the
heater 40 to define a pair of preheating chambers or channels 48,
50 through which air can enter the smoking system as indicated by
the arrows in FIG. 3. At least one of the ribs 44, 46 also extends
axially beyond the heater 40 and functions as a spacer to hold the
heater 40 away from the end wall 52 of the shroud 42.
[0038] The cross-sectional area of the channels 48, 50 may be
selected as desired. For example, it may be desired to provide a
flow area around the heater 40 which is equivalent to the flow area
through the inside of the heater 40. Or, it may be desired to
provide a flow area equivalent to the flow area through the tobacco
plug 24. Regardless of the flow area selected, the heater 40 is
preferably spaced from the end wall 52 by a sufficient distance
that the flow area at the inner end of the heater 40 is at least as
large as the flow area through the channels 48, 50. In this manner,
the puff resistance (resistance-to-draw) is defined by the tobacco
plug rather than by the assembly of the heater 40 and the shroud
42.
[0039] With the arrangement of FIGS. 3 and 4, air entering the
electric tobacco smoking system, see arrows 54, flows axially
through the preheating chambers or channels 48, 50 between the
heater 40 and the shroud 42. During that time, the air is heated by
thermal energy that might otherwise escape from the outer surface
of the heater 40. That air then passes around the end of the
heater, and flows through the tobacco plug 24 where it picks up
flavorful volatiles from the tobacco heated by the heater 40. As
the air 54 leaves the heater 40, it cools so that the volatiles
condense and form the aerosol 56 for delivery from the heating
system 22.
[0040] If desired, the spacing between the heater 40 and the shroud
42 may be accomplished with structures other than the longitudinal
ribs described above. For example, discontinuous ribs, radially
extending pins, and baffles may be used as desired. Baffles might
be used to improve heat transfer to air under some
circumstances.
[0041] Thus, the embodiment of FIGS. 3 and 4 improves the heat
transfer to air and is more efficient than embodiments without the
shroud 42.
[0042] The electric tobacco smoking system of this disclosure may
also include a mouthpiece 60 (see FIGS. 5 and 6) having an end in
fluid communication with the tobacco mass. The mouthpiece 60 may be
constructed and arranged such that it has a cross-sectional
configuration corresponding to the cross section of the heater
assembly 22. In addition, the mouthpiece 60 may include a generally
cylindrical shell 62 and an attachment sheath 64. The shell 62
preferably extends outwardly from the tobacco plug 24, has an open
interior, and provides a channel or passage to deliver the aerosol
32. The shell 62 also functions to provide structural support for
the heater 22 and tobacco plug 24. The sheath 64 preferably
surrounds the shell 62 and may be constructed from paper or any
other suitable conventional material.
[0043] The sheath 64 extends beyond the end of the shell 62 and
into an opening within the heating assembly 22, which opening may
be between the heating assembly 22 and the tobacco mass. By
attaching the sheath 64 to the electric tobacco smoking system 20,
the combination of the smoking system 20 and the mouthpiece 60
cosmetically resembles a conventional cigarette.
[0044] When more than one mouthpiece 60 will be used with the
smoking system 20, or when one mouthpiece 60 will be used with more
than one smoking system 20, the sheath may be fabricated from a
sufficiently rigid material that the mouthpiece can be removably
attached to the smoking system 20 by inserting the extending
portion of the sheath 64 between the heating assembly 22 and the
tobacco plug 24. For some applications, it may also be desirable to
provide a suitable filter (not shown) such as a plug of cellulose
acetate in the discharge end of the mouthpiece 60. Typically, such
a filter would be located at an end of the mouthpiece. The
actuation system of FIG. 5 is like that of FIG. 1 and includes
conductors 36, batteries 37, and a switch 38; however, in FIG. 5,
the switch 38 may be a puff sensing device or an air flow sensing
device.
[0045] Another arrangement for the heating assembly is shown in
FIGS. 7 and 8. In this embodiment, the heating assembly includes an
end piece 70 and a projection 72. The projection 72 may, for
example, be a rod constructed and arranged so that it can be
inserted into and received by the tobacco plug 24. The axial length
of the projection 72 is selected so that it does not extend all the
way through the tobacco plug. The end piece or heater disk 70
includes air passages or openings 74, 76 through which air can be
introduced into the tobacco plug 24. At least one of the end piece
70 and the projection 72 may be energized to generate heat, e.g.,
by resistance heating or induction heating. Presently it is
contemplated that both the end piece 70 and the projection 72 are
capable of generating heat. However, if the tobacco plug 24 has a
small diameter compared to the transverse dimensions of the
projection 72, sufficient heat may be generated by the projection
72 that additional heat from the end piece 70 is not needed. The
actuation system of FIG. 7 is like that of FIG. 1 and includes
conductors 36, batteries 37, and a switch 38.
[0046] While the end piece 70 is depicted with two openings, the
number, arrangement, and shape of the openings can vary. For
example, a pattern of circular holes could be used if desired.
Where the end piece 70 is heated, heat transfer to the air passing
through the openings can be increased by using smaller
openings.
[0047] If desired, the heating assembly 70, 72 and the associated
tobacco plug 24 may be enclosed in other structures. For example, a
cylindrical shell may surround the tobacco plug, or the tobacco
plug along with the end piece 70. Such a cylindrical shell could
also include a mouthpiece portion.
[0048] The embodiments discussed above include a generally
cylindrical plug of tobacco; however, that shape for the tobacco is
not critical. The cross section may be circular, as shown.
Alternatively, the cross section can be uniform or non-uniform and
can have any desired shape such a polygonal, elliptical, oval,
toroidal, and the like. Moreover, the tobacco can have other
suitable shapes as will be apparent to those skilled in the art.
For example, the tobacco can be shaped as a pillow, i.e., a unit
having a depth which is small compared with the transverse
dimension. The pillow may be circular, rectangular, polygonal,
polygonal with rounded corners, toroidal, or the like.
[0049] A generally circular embodiment of the pillow arrangement is
depicted in FIGS. 9 and 10. Here, the pillow 80 is fashioned from
cut filler tobacco. As desired, the pillow 80 may include a
permeable membrane surrounding it to hold its shape and facilitate
handling. The thickness of the pillow 80 may be in the range of
10-80% of a nominal transverse dimension of the pillow 80. In the
context of FIG. 9, the nominal transverse dimension would be
measured in the vertical direction and would correspond to the
diameter of the pillow 80. The pillow thickness would be measured
in the horizontal direction, axially in the direction of
airflow.
[0050] The heating system 82 for this embodiment comprises a
heating plate in heat transfer relationship with the tobacco pillow
80. The actuation system of FIG. 9 is like that of FIG. 1 and
includes conductors 36, batteries 37, and a switch 38. The plate 82
may be a generally circular disk and may include a plurality of
openings 84 to permit air to flow into the pillow 80. Those
openings 84 may have any desired shape. In some applications, the
openings 84 will be sized to provide heat transfer from the heating
plate 82 to air (see arrows 86) before the air enters the tobacco
pillow 80.
[0051] Thermal energy from the plate 82 is applied to the tobacco
pillow 80 by conduction and convection so that the temperature of
the pillow is raised to release the flavorful volatiles. As with
other embodiments, that temperature lies in the range of about
150.degree. to about 220.degree. C. As air leaves the tobacco
pillow with the entrained flavorful volatiles (see arrows 88), the
flavorful volatiles cool to form an aerosol (see arrow 90).
[0052] A pillow 80 having radial air inflow and axial outflow is
shown in FIGS. 11 and 12. In this embodiment, the heating
arrangement may include a disk-shaped heater 92 and an annular
heater 94. The disk heater 92 and the annular heater 94 are spaced
from one another by a distance corresponding to the thickness of
the pillow 80 and sandwich the pillow therebetween. Both the disk
heater 92 and the annular heater 94 have heat transfer relationship
with the pillow 80 so that the heaters 92, 94 can raise the
temperature of tobacco in the pillow 80 to a temperature sufficient
to release the flavorful volatiles (i.e., about 150.degree. to
about 220.degree. C.). The actuation system of FIG. 11 is like that
of FIG. 1 and includes conductors 36, batteries 37, and a switch
38.
[0053] In this arrangement, ambient air enters the pillow 90 in a
generally radial direction, for example, in response to inhalation.
As the ambient air passes through the pillow 80, its temperature
rises by heat transfer from one or both of the heaters 92, 94 and
it entrains volatiles released from the tobacco. Air with the
flavorful tobacco volatiles, turns axially and leaves the assembly
through a generally circular orifice or opening 96 in the center of
the annular heater 94. The air with entrained tobacco volatiles
cools as it leaves the heater and condenses to form an aerosol
(arrow 98).
[0054] To enhance the heating efficiency of the embodiment of FIGS.
11 and 12, the assembly of a tobacco pillow 80, the disk heater 92,
and the annular heater 94 may be enclosed in a housing 100 (see
FIGS. 13 and 14). The housing 100 may include a wall 102 fabricated
from an insulating material to reduce heat loss from the disk
heater 92. Preferably the insulating wall 102 is substantially
coextensive with the disk heater 92. The housing 100 also includes
a baffle portion 103 attached to the insulating wall 102 and
operable to direct airflow into the tobacco mass. The baffle 103 is
spaced radially from both the disk heater 92 and the annular heater
94. Moreover, the baffle 103 is spaced axially in front of the
annular heater 94. Although the actuation system is not
schematically shown in FIG. 13, the actuation system for FIG. 13 is
like that of FIG. 1 and includes conductors, batteries, and a
switch.
[0055] With that arrangement, the baffle 103 forms an internal
channel 104, which receives ambient air through an annular opening
106 and directs that ambient air radially outwardly through a
preheating passage, defined between the annular heater 94 and the
baffle, to a collector substantially surrounding the peripheral
edge of the pillow 80. As the air passes the annular heater 94 in
the channel 104, the air is heated thereby reducing energy loss or
waste from the annular heater 94. The heated air then passes
radially inwardly through the pillow 80 between the disk heater 92
and the annular heater 94 and leaves through the generally circular
opening 96.
[0056] A generally cylindrical connector tube 108 with a generally
circular cross section is fitted into the opening 96 and provides a
passageway for heated air with entrained tobacco volatiles leaving
the pillow 80 through the opening 96. In addition, the tube 108
cooperates with the central opening 110 of the baffle 103 to define
an annular inlet opening 106. As air leaves the tube 108, it cools
and the entrained tobacco volatiles form an aerosol.
[0057] Use of a generally toriodal tobacco mass is depicted in
FIGS. 15 and 16. Here, the structural characteristics of the
electric tobacco heater are essentially the same as those of the
heater described above in connection with FIGS. 13 and 14. Although
the actuation system is not schematically shown in FIG. 15, the
actuation system for FIG. 15 is like that of FIG. 1 and includes
conductors, batteries, and a switch. The principal difference being
the tobacco mass, which is used. Here the tobacco mass 120 is
generally toroidally shaped, i.e., shaped like a donut. The tobacco
donut 120 is sandwiched between the disk heater 92 and the annular
heater 94 so that the tobacco donut contacts both heaters. In this
way, air is forced to travel through the tobacco donut 120.
Preferably, the tobacco donut does not extend outwardly to touch
the shell 103 so that the passageway for air is not obstructed.
[0058] The electric tobacco heater (FIG. 15) is shown with a
mouthpiece 122 attached at one end to the tube 108. At the other
end, the mouthpiece 122 may include a suitable filter 124.
[0059] It is also contemplated that the tobacco mass may be
arranged so that successive portions of the tobacco mass can be
advanced to the heating system. Individual tobacco mass portions
may be used for a time corresponding generally to one puff, to
multiple puffs, or to correspond to a time comparable to the
smoking of a conventional cigarette. The embodiments of FIGS. 9-12
are particularly well suited for such applications. For example,
successive tobacco mass portions may be carried on a tape and
advanced into position relative to the heating system by a suitable
indexing arrangement. Alternatively, the tobacco mass portions may
be carried by a cassette, or may comprise discrete packages.
[0060] The terms and phases used herein are not to be interpreted
with mathematical or geometric precision, rather geometric
terminology is to be interpreted as meaning approximating or
similar to the geometric terms and concepts. Where the term "about"
is used in relation to a number, it is intended that such number
has a tolerance of plus or minus 5%. Similarly, such terms as
"generally" and "substantially" are intended to encompass both
precise meanings of the associated terms and concepts as well as to
provide reasonable latitude which is consistent with form,
function, and/or meaning.
[0061] It will now be apparent to those skilled in the art that
this specification describes a new, useful, and nonobvious
smokeless electric tobacco smoking system. It will also be apparent
to those skilled in the art that numerous modifications,
variations, substitutes, and equivalents exist for various aspects
of the invention that have been described in the detailed
description above. Accordingly, it is expressly intended that all
such modifications, variations, substitutions, and equivalents that
fall within the spirit and scope of the invention, as defined by
the appended claims, be embraced thereby.
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