U.S. patent application number 10/076101 was filed with the patent office on 2003-08-21 for electrical smoking system and method.
Invention is credited to Fournier, Jay A., Paine, John B. III.
Application Number | 20030154991 10/076101 |
Document ID | / |
Family ID | 27732474 |
Filed Date | 2003-08-21 |
United States Patent
Application |
20030154991 |
Kind Code |
A1 |
Fournier, Jay A. ; et
al. |
August 21, 2003 |
ELECTRICAL SMOKING SYSTEM AND METHOD
Abstract
An electrical smoking system comprising a cigarette and an
electric lighter, wherein the cigarette comprises a wrapper
surrounding a tubular tobacco mat partially filled with material
tobacco so as to define a filled tobacco rod portion and an
unfilled tobacco rod portion. The wrapper includes an ammonium
containing compound filler therein effective to reduce gaseous
components of the tobacco smoke produced during smoking of the
cigarette. The system includes a lighter comprising at least one
heating blade and a controller adapted to control heating of the
heater blade, the lighter arranged to at least partially receive
the cigarette such that the heater blade heats a heating zone of
the cigarette. The controller is operable to limit heating of the
heater blade to a predetermined temperature range which allows
delivery of tobacco smoke generated by heating the tobacco rod
portion while reducing the content of at least one gaseous
component in the tobacco smoke compared to smoking a cigarette
having only calcium carbonate as the wrapper filler. The gaseous
components which can be reduced include carbon monoxide,
1,3-butadiene, isoprene, acrolein, acrylonitrile, hydrogen cyanide,
o-toluidine, 2-naphtylamine, nitrogen oxide, benzene, NNN, phenol,
catechol, benz(a)anthracene, and benzo(a)pyrene.
Inventors: |
Fournier, Jay A.; (Richmond,
VA) ; Paine, John B. III; (Midlothian, VA) |
Correspondence
Address: |
Peter K. Skiff
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
27732474 |
Appl. No.: |
10/076101 |
Filed: |
February 15, 2002 |
Current U.S.
Class: |
131/194 |
Current CPC
Class: |
A24D 3/17 20200101; A24F
40/50 20200101; A24D 1/02 20130101; A24D 1/20 20200101; A24F 40/46
20200101; A24F 40/20 20200101 |
Class at
Publication: |
131/194 |
International
Class: |
A24F 001/22 |
Claims
1. An electrical smoking system comprising: a cigarette comprising
a tubular tobacco mat partially filled with tobacco material so as
to define a filled tobacco rod portion, the filled tobacco rod
portion being adjacent a free end of cigarette, the cigarette
including a wrapper surrounding the filled tobacco rod portion, the
wrapper comprising a cellulosic web material and at least one
filler therein, the filler comprising an ammonium containing
compound in an amount effective to reduce the content of gaseous
components in tobacco smoke produced upon combustion/pyrolysis of
the tobacco rod portion; and a lighter comprising at least one
heating blade and a controller adapted to control heating of the
heater blade in accordance with a power cycle, the lighter arranged
to at least partially receive the cigarette such that the heater
blade heats a heating zone of the cigarette, the controller being
operable to limit heating of the heating zone to no greater than
500.degree. C. so as to produce tobacco smoke while reducing the
content of at least one gaseous component in the tobacco smoke, the
at least one gaseous component including carbon monoxide,
1,3-butadiene, isoprene, acrolein, acrylonitrile, hydrogen cyanide,
o-toluidine, 2-naphtylamine, nitrogen oxide, benzene, NNN, phenol,
catechol, benz(a)anthracene, and benzo(a)pyrene.
2. The electrical smoking system according to claim 1, wherein the
controller limits heating of the heating zone to a temperature no
greater than 450.degree. C.
3. The electrical smoking system according to claim 1, wherein the
heating zone covers an area of 10 to 20 mm.sup.2 and the controller
limits heating of the heater blade to heat the tobacco mat adjacent
the heating zone to a temperature range of 200 to 350.degree. C. by
supplying the heating blade with 15 to 40 Joules of energy,
preferably 20 to 35 Joules.
4. The electrical smoking system according to claim 1, wherein the
lighter includes a heater fixture having a plurality of the heating
blades and a socket which occludes an axial end of the tobacco rod
portion.
5. A cigarette for use in the electrical smoking system according
to claim 1, wherein the cigarette includes a zone of perforations
spaced from the free end of the tobacco rod portion.
6. The cigarette as claimed in claim 5, wherein the cigarette
includes filtering material.
7. The cigarette as claimed in claim 5, further comprising a
plurality of circumferentially spaced-apart holes in the tubular
tobacco mat, the holes being covered by the wrapper.
8. The cigarette as claimed in claim 7, wherein the tubular tobacco
mat comprises a tubular base web and a layer of tobacco material
disposed along an interior of the tubular base web, the holes
extending through the base web and the layer of tobacco
material.
9. The cigarette as claimed in claim 7, wherein the mat holes are
approximately 1 mm in diameter and 6 in number, arranged in a row
and the zone of perforations comprises one or two rows of
perf-holes, each row having 12 perf-holes.
10. The cigarette as claimed in claim 5, wherein the filler
comprises only ammonium magnesium phosphate filler.
11. The cigarette as claimed in claim 10, wherein the ammonium
magnesium phosphate filler consists essentially of the monohydrate
form of magnesium ammonium phosphate.
12. A method of using the electrical smoking system according to
claim 1, comprising supplying electrical current from a battery to
the heating blade in accordance with the power cycle, the power
cycle being implemented by the controller in a manner such that the
heater blade heats the heating zone of the cigarette so as to
generate tobacco smoke while reducing the content of at least one
gaseous component in the tobacco smoke, the at least one gaseous
component including carbon monoxide, 1,3-butadiene, isoprene,
acrolein, acrylonitrile, hydrogen cyanide, o-toluidine,
2-naphtylamine, nitrogen oxide, benzene, NNN, phenol, catechol,
benz(a)anthracene, and benzo(a)pyrene.
13. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of carbon monoxide by at least about 40%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
14. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of 1,3-butadiene by at least about 40%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
15. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of isoprene by at least about 30%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
16. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of acrolein by at least about 10%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
17. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of formaldehyde by at least about 70%,
acetaldehyde by at least about 30%, and propionaldehyde by at least
about 40% compared to using the electrical smoking system to smoke
the same type of cigarette having only calcium carbonate as the
filler in the wrapper.
18. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of acrylonitrile by at least about 40%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
19. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of hydrogen cyanide by at least about
20% compared to using the electrical smoking system to smoke the
same type of cigarette having only calcium carbonate as the filler
in the wrapper.
20. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of o-toluidine by at least about 30%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
21. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of 2-naphtylamine by at least about 15%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
22. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of nitrogen oxides by at least about 30%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
23. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of benzene by at least about 40%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
24. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of toulene by at least about 40%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
25. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of NNN by at least about 25% compared to
using the electrical smoking system to smoke the same type of
cigarette having only calcium carbonate as the filler in the
wrapper.
26. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of phenol by at least about 30% compared
to using the electrical smoking system to smoke the same type of
cigarette having only calcium carbonate as the filler in the
wrapper.
27. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of catechol by at least about 25%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
28. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of bena(a)anthracene by at least about
60% compared to using the electrical smoking system to smoke the
same type of cigarette having only calcium carbonate as the filler
in the wrapper.
29. The method according to claim 12, wherein heater blade heats
the heating zone of the cigarette so as to generate tobacco smoke
while reducing the content of benzo(a)pyrene by at least 50%
compared to using the electrical smoking system to smoke the same
type of cigarette having only calcium carbonate as the filler in
the wrapper.
30. The method according to claim 12, wherein the filler ranges
from about 10% to about 60% by weight based on the total weight of
the wrapper, the wrapper is a single layer wrapper which includes
at least one circumferential row of perforations, the wrapper has a
basis weight of between about 15 g/m.sup.2 to about 75 g/m.sup.2
and a porosity of between about 2 CORESTA units to about 200
CORESTA units, and/or the wrapper includes from about 2% to about
15% by weight of a burn additive comprising at least one alkali
metal salt of an acid selected from the group consisting of sodium
fumarate, sodium citrate, potassium citrate, potassium succinate,
potassium monohydrogen phosphate, and potassium dihydrogen
phosphate.
31. The method according to claim 12, wherein the wrapper has a
basis weight of between about 25 g/m.sup.2 to about 35 g/m.sup.2
and a porosity of between about 25 CORESTA units to about 45
CORESTA units, the amount of the filler ranges from about 20% to
about 40% by weight based on the total weight of the wrapper,
and/or the filler has an average particle size of less than 5
.mu.m.
Description
FIELD OF INVENTION
[0001] The present invention relates to electrical smoking systems
and methods of reducing gaseous components during smoking.
BACKGROUND OF INVENTION
[0002] Traditional cigarettes are consumed by lighting an end of a
wrapped tobacco rod and drawing air predominately through the lit
end by suction at a mouthpiece end of the cigarette. Traditional
cigarettes deliver smoke as a result of combustion, during which a
mass of tobacco is combusted at temperatures which often exceeds
800.degree. C. during a puff. The heat of combustion releases
various gaseous combustion products and distillates from the
tobacco. As these gaseous products are drawn through the cigarette,
they cool and condense to form a smoke containing the tastes and
aromas associated with smoking. Traditional cigarettes produce
sidestream smoke during smoldering between puffs. Once lit, they
must be filly consumed or be discarded. Relighting a traditional
cigarette is possible but is usually an unattractive proposition to
a discerning smoker for subjective reasons (flavor, taste,
odor).
[0003] In an electrical smoking system, it is desirable to deliver
smoke in a manner that meets the smokers experiences with more
traditional cigarettes, such as an immediacy response (smoke
delivery occurring instant upon draw), a desired level of delivery
(which correlates with FTC tar level), together with a desired
resistance to draw (RTD) and consistency from puff to puff and from
cigarette to cigarette.
[0004] Commonly assigned U.S. Pat. Nos. 5,060,671; 5,144,962;
5,372,1485,388,594; 5,498,855; 5,499,636; 5,505,214; 5,530,225;
5,591,368; 5,665,262; 5,666,976; 5,666,978; 5,692,291; 5,692,525;
5,708,258; 5,750,964; 5,902,501; 5,915,387; 5,934,289; 5,954,979;
5,967,148; 5,988,176; 6,026,820 and 6,040,560 disclose electrical
smoking systems and methods of manufacturing a cigarette, which
patents are incorporated by reference.
SUMMARY OF INVENTION
[0005] The invention provides an electrical smoking system which
includes a cigarette and a lighter. The cigarette comprises a
tubular tobacco mat partially filled with tobacco material so as to
define a filled tobacco rod portion, the filled tobacco rod portion
being adjacent a free end of cigarette. The cigarette includes a
wrapper surrounding the filled tobacco rod portion, the wrapper
comprising a cellulosic web material and at least one filler
therein, the filler comprising an ammonium containing compound in
an amount effective to reduce the content of gaseous components in
tobacco smoke produced upon combustion/pyrolysis of the tobacco rod
portion. The lighter includes at least one heating blade and a
controller adapted to control heating of the heater blade, the
lighter arranged to at least partially receive the cigarette such
that the heater blade heats a heating zone of the cigarette, the
controller being operable to limit heating of the heating zone to
no greater than 500.degree. C. so as to produce tobacco smoke while
reducing the content of at least one gaseous component in the
tobacco smoke, the at least one gaseous component including carbon
monoxide, 1,3-butadiene, isoprene, acrolein, acrylonitrile,
hydrogen cyanide, o-toluidine, 2-naphtylamine, nitrogen oxide,
benzene, NNN, phenol, catechol, benz(a)anthracene, and
benzo(a)pyrene.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Various features of the present invention are shown in the
drawings in which like numerals indicate similar elements.
[0007] FIG. 1 is a perspective view of a smoking system in
accordance with a preferred embodiment of the present invention
with a cigarette of the system inserted into the electrically
operated lighter.
[0008] FIG. 2 is a perspective view of the smoking system of FIG.
1, but with the cigarette withdrawn from the lighter upon
conclusion of a smoking.
[0009] FIG. 3A is a partial perspective detail view of portions of
the heater fixture of FIG. 1, including wavy hairpin heater
elements and portions of a preferred air admission system;
[0010] FIG. 3B is a sectional side view of a preferred heater
fixture which includes the wavy hairpin heater elements of FIG.
3A.
[0011] FIG. 3C is a side view of the cigarette shown in FIG. 4
inserted into the heater fixture of FIG. 6, with the latter being
shown in cross-section.
[0012] FIG. 4 is a detail perspective view of a preferred
embodiment of the cigarette shown in FIG. 1, with certain
components of the cigarette being partially unraveled.
[0013] FIG. 5 is a schematic, block-diagram of a preferred control
circuit for the lighter shown in FIGS. 1 and 2.
[0014] FIG. 6 is a side cross sectional view of the cigarette shown
in FIG. 4 wherein a free end of the cigarette is in contact with a
stop piece in the lighter.
[0015] FIGS. 7 and 8 are graphs showing reduction of various
gaseous components of tobacco smoke generated with the smoking
system according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Referring to FIGS. 1 and 2, a preferred embodiment of the
present invention provides a smoking system 21 which preferably
includes a partially-filled, filter cigarette 23 and a reusable
lighter 25. The cigarette 23 is adapted to be inserted into and
removed from a cigarette receiver 27 which is open at a front end
portion 29 of the lighter 25. Once the cigarette 23 is inserted,
the smoking system 21 is used in much the same fashion as a more
traditional cigarette, but without lighting or smoldering of the
cigarette 23. The cigarette 23 is discarded after one or more puff
cycles.
[0017] Preferably, each cigarette 23 provides a total of eight
puffs (puff cycles) or more per smoke; however it is a matter of
design expedient to adjust to a lesser or greater total number of
available puffs. In the preferred embodiment, the cigarette 23
includes at least one peripheral ring of perforations 12 located
adjacent the free end 15 of the cigarette 23 and optionally a
second ring or rings of perforations 14 and optionally a plurality
of holes 16 underneath the outer wrapper of the cigarette 23.
[0018] The lighter 25 includes a housing 31 having front and rear
housing portions 33 and 35. One or more batteries 35a are removably
located within the rear housing portion 35 and supply energy to a
heater fixture 39 which includes a plurality of electrically
resistive, heating elements 37 (shown in FIGS. 3A-C). The heating
elements 37 are arranged within the front housing portion 33 to
slidingly receive the cigarette 23 along an intermediate portion of
the cigarette receiver 27. A stop 183 located at the base 300 of
the heater fixture 39 defines a terminus of the cigarette receiver
27.
[0019] A controller includes a control circuit 41 in the front
housing portion 33 which selectively establishes electrical
communication between the batteries 35a and one or more the heater
elements 37 during execution of each puff cycle. The preferred
embodiment of the present invention includes details concerning an
air management system for effecting the admission and routing of
air within the lighter, including aspects which are discussed in
greater detail beginning with reference to FIG. 3C.
[0020] Still referring to FIGS. 1 and 2, preferably the rear
portion 35 of the lighter housing 31 is adapted to be readily
opened and closed, such as with screws or snap-fit components, so
as to facilitate replacement of the batteries. If desired, an
electrical socket or contacts may be provided for recharging the
batteries in a charger supplied with house current or the like.
Preferably, the front housing portion 33 is removably joined to the
rear housing portion 35, such as with a dovetail joint or a socket
fit.
[0021] The batteries 35a are sized to provide sufficient power for
the heaters 37 to function as intended and preferably comprise a
replaceable and rechargeable type. Alternate sources of power are
suitable, such as capacitors. In the preferred embodiment, the
power source comprises four nickel-cadmium battery cells connected
in series with a total, non-loaded voltage in the range of
approximately 4.8 to 5.6 volts. The characteristics of the power
source are, however, selected in view of the characteristics of
other components in the smoking system 21, particularly the
characteristics of the heating elements 37. Commonly assigned U.S.
Pat. No. 5,144,962, hereby incorporated by reference, describes
several types of power sources useful in connection with the
smoking system of the present invention, such as rechargeable
battery sources and power arrangements which comprise a battery and
a capacitor which is recharged by the battery.
[0022] Referring specifically to FIG. 2, preferably, the circuitry
41 is activated by a puff-actuated sensor 45 that is sensitive to
either changes in pressure or changes in rate of air flow that
occur upon initiation of a draw on the cigarette 23 by a smoker.
The puff-actuated sensor 45 is preferably located within the front
housing portion 33 of the lighter 25 and is communicated with a
space inside the heater fixture 39 adjacent the cigarette 23 via a
port 45a extending through a side wall portion 182 of the heater
fixture 39. A puff-actuated sensor 45 suitable for use in the
smoking system 21 is described in commonly assigned U.S. Pat. Nos.
5,060,671 and 5,388,594, the disclosures of which are incorporated
herein by reference. The puff sensor 45 preferably comprises
Fujikura Ltd. Model FSS-02 PG. Another suitable sensor is a Model
163PCO1D35 silicon sensor, manufactured by the MicroSwitch division
of Honeywell, Inc., Freeport, Ill. Flow sensing devices, such as
those using hot-wire anemometry principles, have also been
successfully demonstrated to be useful for actuating an appropriate
one of the heater elements 37 upon detection of a change in air
flow. Once actuated by the sensor 45, the control circuitry 41
directs electric current to an appropriate one of the heater
elements 37.
[0023] An indicator 51 is provided at a location along the exterior
of the lighter 25, preferably on the front housing portion 33, to
indicate the number of puffs remaining in a smoke of a cigarette
23. The indicator 51 preferably includes a seven-segment liquid
crystal display. In the preferred embodiment, the indicator 51
displays a segmented image which correlates with the digit "8" when
a cigarette detector 57 detects the presence of a cigarette in the
heater fixture 39. The detector 57 preferably comprises an
inductive coil 1102 adjacent the cigarette receiver 27 of the
heater fixture 39 and electric leads 1104 that communicate the coil
1102 with an oscillator circuit within the control circuitry 41.
The cigarette 23 internally bears a foil ring or the like which can
affect inductance of the coil winding 1102 such that whenever a
cigarette 23 is inserted into the receiver 27, the detector 57
generates a signal to the circuitry 41 indicative of the cigarette
being present. The control circuitry 41 in turn provides a signal
to the indicator 51. The display of the digit 8 on the indicator 51
reflects that the eight puffs provided on each cigarette 23 are
available, i.e., no puff cycle has been undertaken and none of the
heater elements 37 have been activated to heat the cigarette 23.
After the cigarette 23 is fully smoked, the indicator displays the
digit "0". When the cigarette 23 is removed from the lighter 25,
the cigarette detector 57 no longer detects a presence of a
cigarette 23 and the indicator 51 is turned off.
[0024] The operation and details of the inductive cigarette
detector 57 is provided in commonly assigned U.S. Pat. No.
5,902,501, which is incorporated herein by reference in its
entirety. Other detectors may be employed instead of the
above-described one for the detector 57, such as a Type OPR5005
Light Sensor, manufactured by OPTEX Technology, Inc., 1215 West
Crosby Road, Carrollton, Tex. 75006.
[0025] In the alternative to displaying the remainder of the puff
count, the detector display may instead be arranged to indicate
whether the system is active or inactive ("on" or "off").
[0026] As one of several possible alternatives to using the
above-noted cigarette detector 57, a mechanical switch (not shown)
may be provided to detect the presence or absence of a cigarette 23
and a reset button (not shown) may be provided for resetting the
circuitry 41 when a new cigarette is inserted into the lighter 25,
e.g., to cause the indicator 51 to display the digit "8", etc.
Power sources, circuitry, puffactuated sensors, and indicators
useful with the smoking system 21 of the present invention are
described in commonly assigned, U.S. Pat. Nos. 5,060,671; 5,388,594
and 5,591,368, all which are incorporated herein by reference.
[0027] Referring now to FIGS. 3A and 3B, the front housing portion
33 of the lighter 25 encloses a substantially cylindrical heater
fixture 39 whose heater elements 37 slidingly receive the cigarette
23. The heater fixture 39 is adapted to support an inserted
cigarette 23 in a fixed relation to the heater elements 37 such
that the heater elements 37 are positioned alongside the cigarette
23 at approximately the same location along each newly inserted
cigarette 23. In the preferred embodiment, the heater fixture 39
includes eight mutually parallel heater elements 37 which are
disposed concentrically about the axis of symmetry of the cigarette
receiver 27. The locations where each heater element 37 bears
against (or is in thermal communication with) a fully inserted
cigarette 23 is referred to herein as the heater footprint or char
zone 42. In the preferred embodiment, the char zone may extend
approximately 14 mm in length, beginning approximately 9 mm from
the free-end 15 of the cigarette 23. Of course, these relations may
be varied amongst different lighter and cigarette designs. In
another model for example, the char zone 42 extends from 12 mm to
23 mm from the free-end of the cigarette 23.
[0028] Referring also to FIG. 3C, to assure consistent placement of
the heating elements 37 relative to each cigarette 23 from
cigarette to cigarette, the heater fixture 39 is provided with a
base portion 300 having a cupped stop-piece 183 against which the
free end 15 of the cigarette 23 is urged during its insertion into
the cigarette receiver 27 of the lighter 25. The cupped shape of
the stop-piece 183 is configured to close-off (occlude) the free
end 15 of the cigarette 23 upon full insertion of the cigarette 23
so that air cannot be drawn through the free end 15, but instead
only from along the side walls of the cigarette 23.
[0029] Still referring to FIGS. 3A and 3B, most preferably the
heater elements 37 are of a design referred to herein as a wavy
hairpin heater element 37, wherein each heater element 37 includes
at least first and second serpentine, elongate members 53a and 53b
which are adjoined at an end portion (tip) 54. The tips 54 are
adjacent the opening 55 of the cigarette receiver 27. The opposite
ends 56a and 56b of each heater element 37 are electrically
connected to the opposite poles of the power source 35a as
selectively established by the controller 41. More specifically, an
electrical pathway through each heater fixture 37 is established,
respectively, through a terminal pin 104, a connection 121 between
the pin 104 and a free end portion 56a of one of the serpentine
members 53a, through at least a portion of the tip 54 to the other
serpentine member 53b and its end portion 56b. Preferably, an
integrally formed, common connection ring 110 provides a common
electrical connection amongst all the end portions 56b of the
elongate member 53b. In the preferred embodiment, the ring 110 is
connected to the positive terminal of the power source 35a (or
common) through a connection 123 between the ring 110 and a pin
105. Further details of the construction and establishment of
electrical connections in the heater fixture 39 are illustrated and
described in the commonly assigned U.S. Pat. Nos. 5,060,671;
5,388,594 and 5,591,368, all which are incorporated herein by
reference. The heater portions 53a, 53b and 54 establish what is
here referred to as a heater blade 120.
[0030] Other preferred designs of the heater fixture 39 include
heater elements in the form of a straight hairpin heater elements
37, which are set forth in the commonly assigned U.S. Pat. No.
5,591,368 and "singular serpentine" heater elements each which are
set forth in commonly assigned U.S. Pat. No. 5,388,594, said
patents being incorporated herein by reference in their
entireties.
[0031] Additional heater fixtures 37 that are operable as part of
the lighter 25 include those disclosed in commonly assigned, U.S.
Pat. No. 5,665,262; and commonly assigned, U.S. Pat. No. 5,498,855,
all which are incorporated herein by reference in their
entireties.
[0032] Preferably, the heaters 37 are individually energized by the
power source 35a under the control of the circuitry 41 to heat the
cigarette 23 preferably eight times at spaced locations about the
periphery of the cigarette 23. The heating renders eight puffs from
the cigarette 23, as is commonly achieved with the smoking of a
more traditional cigarette. It may be preferred to activate more
than one heater simultaneously for one or more or all of the
puffs.
[0033] Referring now to FIG. 4, the cigarette 23 is preferably
constructed in accordance with the preferred embodiment set forth
in commonly assigned, U.S. Pat. No. 5,499,636, herein incorporated
by reference in its entirety.
[0034] Referring particularly to FIGS. 3A, 3B, and 3C, preferably
the puff sensor 45 is communicated to the interior of the heater
fixture 39 through a port 45a. Preferably, the port 45a is located
adjacent the base portion 300 of the heater fixture 39. Such
location minimizes the risk that the port 45a and adjacent
passageways leading thereto through the body of the heater fixture
39 would become clogged by the debris or smoke condensates.
[0035] The heater fixture 39 includes an air inlet port 1200, which
communicates with a manifold 1202 that is at least partially
defined by a perforated annulus 1204 and the body of the receiver
27. The annulus 1204 includes preferably four holes 1206 of
approximately 0.029 inch diameter for effecting a minimal pressure
drop as air is drawn into the lighter through the air inlet port
1200 and the manifold 1202. The size and number of the holes 1206
may be varied, but such are configured to provide sufficient
pressure drop that upon drawing action upon an inserted cigarette
23, a pressure drop is induced upon the air entering the lighter
such that the puff sensor 45 is operative to recognize initiation
of a puff. In the preferred embodiment, the holes 1206 of the
annulus 1204 induce an RTD of approximately 25 mm water plus or
minus 5 mm. The range of pressure drop induced at the annulus 1204
should be selected such that it is within the range of pressure
drop detectable by the pressure sensor 45, but minimized to that
need so that the remainder of desired RTD (Resistance To Draw) is
effected predominantly by the cigarette 23. In the preferred
embodiment, a grand total RTD of 4 to 5 inches water (100 to 130 mm
water) is desired and approximately 25 mm of that is produced at
the annulus 1204. Accordingly, the RTD of the cigarette 23 is
preferably in the range of approximately 75 to 105 mm water RTD,
when inserted in lighter 25 and the induced pressure drop of the
lighter 25 is approximately 25 mm water. Adjustment of cigarette
RTD in accordance with the present invention includes provision of
and adjustment of the number and extent of perforations 12 (and
optionally 14) in the filled portion 88 of the cigarette 23.
[0036] Advantageously, the holes 1206 of the annulus 1204, being
located adjacent the receiver 27, is positioned away from sources
of debris and condensates which might otherwise tend to clog the
holes 1206.
[0037] Air that has been drawn into the lighter upon initiation of
a puff enters alongside the cigarette with a substantial
longitudinal (axial) velocity component toward the base portion 300
of the heater fixture 300. It has been discovered that a flow
deflector or annular air-swoop 1210 adjacent the base portion 300
enhanced smoke output (delivery) of the system 21 by directing at
least a portion of the entering airflow back toward the inserted
cigarette 23. Not wishing to be bound by theory, it is believed
that the air-swoop 1210 tends to direct airflow toward regions of
the cigarette 23 bearing perforations 12. Preferably, the annular
air-swoop 1210 is located relative to a fully inserted cigarette 23
such that the air-swoop 1210 circumscribes the general location
along the cigarette 23 of the perforations 12.
[0038] It has been discovered that the functioning of the air-swoop
1210 is improved if it is constructed from metal, or alternatively,
all body portions of the heater fixture 39 are constructed from a
metal such as a stainless steel, or at least those portions of the
heater fixture 39 that are disposed adjacent an inserted cigarette
23. Such provision can provide an increase of delivery of 1 mg TPM
(FTC).
[0039] The cigarette 23 comprises a tobacco rod 60 and a filter
tipping 62, which are joined together with tipping paper 64. The
tobacco rod 60 of the cigarette 23 preferably includes a tobacco
web or "mat" 66 which has been folded into a tubular (cylindrical)
form about a free-flow filter 74 at one of its ends and a tobacco
plug 80 at the other. In the alternative, a plug of cellulose
acetate might be used in place of the tobacco plug 80. The
longitudinal (axial) extent of the tobacco plug 80 defines a
tobacco filled portion 88 of the partially-filled cigarette 23.
[0040] An overwrap 71 is intimately enwrapped about the tobacco web
66 and is held together along a longitudinal seam as is common in
construction of more traditional cigarettes. The overwrap 71
retains the tobacco web 66 in a wrapped condition about a free-flow
filter 74 and a tobacco plug 80.
[0041] The tobacco web 66 itself preferably comprises a base web 68
and a layer of tobacco material 70 located along the inside surface
of the base web 68. At the tipped end of the tobacco rod 60, the
tobacco web 66 together with the overwrap 71 are wrapped about the
tubular free-flow filter plug 74. Preferably, the tobacco plug 80
is constructed separately from the tobacco web 66 and comprises a
relatively short column of cut filler tobacco that preferably has
been wrapped within and retained by a plug wrap 84.
[0042] As a general matter, the length of the tobacco plug 80 is
preferably set relative to the total length of the tobacco rod 60
such that a void 90 is established along the tobacco rod 60 between
the free-flow filter 74 and the tobacco plug 80. The void 90
corresponds to an unfilled portion of the tobacco rod 60 and is in
immediate fluid communication with the tipping 62 through the free
flow filter 74 of the tobacco rod 60.
[0043] The tipping 62 preferably comprises a free-flow filter 92
located adjacent the tobacco rod 60 and a mouthpiece filter plug 94
at the distal end of the tipping 62 from the tobacco rod 60.
Preferably, the free-flow filter 92 is tubular and transmits air
with very little pressure drop. Other low efficiency filters of
standard configuration could be used instead, however. The inside
diameter for the free flow filter 92 is preferably at or between 2
to 6 mm and is preferably greater than that of the free flow filter
74 of the tobacco rod 60.
[0044] The mouthpiece filter plug 94 closes off the free end of the
tipping 62 for purposes of appearance and, if desired, to effect
some filtration, although it is preferred that the mouthpiece
filter plug 94 comprise a low efficiency filter of preferably about
15 to 25 percent efficiency.
[0045] Still referring to FIG. 4, preferably, the partially-filled
cigarette 23 includes at least one row of perforations 12 at a
location adjacent the free end 15 of the tobacco rod portion of the
cigarette 23. Preferably, the row of perforations 12 are twelve
holes in count and may be formed as slits 17 (perf-holes) at a 400
microsecond pulse width setting of a Hauni Model 500-1 on-line
laser perforator system. Each perf-hole 17 of the row of
perforations 12 preferably extends through the outer wrapper 71,
through the tobacco mat 66 and the plug wrap 84.
[0046] Referring now also FIG. 2, preferably, the row of
perforations 12 is located at or adjacent to end portion 42a of the
char zone 42. Such placement is believed to promote entrance of
heated air into the tobacco plug 80 and create other additional
favorable effects upon pyrolysis during a puff cycle such that
delivery (TPM-FTC) is enhanced.
[0047] To further improve delivery, additional row or rows of
perforations 14 comprising perf holes 17 as previously described
may be provided at a location along the filled portion 88 of the
tobacco rod 60 preferably, at a location superposed, or at least
partially superposed, by the heater char zone or footprint 42
and/or alternatively, adjacent the free end 15 of the cigarette 23.
In the latter alternate embodiment, the second row of perforations
14 is established at approximately 4 mm from the free end 15 of the
cigarette 23. Either or both of the perforation rows 12 or 14 may
comprise a single row or a dual row of perf-holes 17.
[0048] The number and extent of perf-holes 17 are resolved in
accordance with two countervailing considerations. The addition of
rows of perforation 12, 14 as described above contributes to
enhanced delivery of the cigarette 23. However, each additional row
of perforations 12, 14 reduces RTD along the side walls of the
cigarettes 23. Preferably, the grand total RTD of the electrical
smoking system 21 should provide the smoker a resistance to draw
approximately the same as that experience with traditional
cigarettes of approximately 4 to 5 inches water (approximately
100-130 mm water) or thereabouts, 80-130 mm water.
[0049] It has been found that at a total energy input of 23.8
Joules to a heater element 37, a cigarette 23 bearing a dual row of
perforations 12 at a location 12 mm from the free end 15 of the
cigarette (dual rows of 12 holes each) can produce deliveries
substantially greater than 3 milligrams TPM (FTC). Further
deliveries may be obtained by addition of a second row or rows of
perforations 14.
[0050] However, each additional row of perf-holes 17 lowers RTD,
which preferably is to remain at or above 100 mm water for the
whole system 21. Should one find that for a given cigarette 23,
additional delivery is desired yet the RTD level is nearing its
lower limit, additional delivery can be obtained by provision of a
plurality of circumferentially spaced-apart holes 16 placed in the
mat 66 itself. Preferably, the mat holes 16 are each approximately
one mm in diameter and preferably 6 in number so that the requisite
tensile strength of the mat material 66 is maintained and may
withstand machine manufacturing. The mat holes can be formed with
apparatus as is described in commonly assigned U.S. Pat. No.
5,666,976, which patent is hereby incorporated by reference in its
entirety.
[0051] Preferably, the holes 16 in the mat 66 are covered by the
outer wrapper 71. Preferably, any row of perforations 12, 14 is
displaced away from the location of the row of mat holes 16 so that
they do not overlap. In a preferred embodiment, the mat holes 16
are located approximately 7 mm from the free-end 15 of the
cigarette 23, and a dual row of perforations 12 is established
approximately 12 mm from the end 15 of the cigarette 23. So
arranged, the cigarette achieves a 6 mg TPM (FTC) or more.
Advantageously, the mat holes 16 can contribute an additional
delivery to the cigarette 23 without the same extent of reduction
in RTD as is experienced with each addition of row of perf-holes
17. Accordingly, one may utilize the rows of perforations 12, 14 to
approximate desired delivery levels for the cigarette 23, with the
mat holes 16 being used to adjust or increase delivery with a
lesser effect on RTD.
[0052] More traditional cigarettes exhibit a resistance to draw
(RTD) of approximately 80 mm to 130 mm water. The lighter of the
electrical smoking system according to the present invention when
tested without a cigarette exhibits an RTD of approximately 20-30
mm water. The cigarettes according to the present invention having
the laser perforations and mat holes as taught herein exhibit an
RTD of approximately 20-30 mm water when drawn upon by themselves
(outside of the lighter of the electrical smoking system), but when
inserted, the electrical smoking system (the lighter and the fully
inserted cigarette) generate an RTD of approximately 50-75 mm
water.
[0053] Referring now to FIGS. 2 and 5, the electrical control
circuitry 41 of the lighter 25 includes a logic circuit 195, which
preferably comprises a micro-controller or an application specific,
integrated circuit (or "ASIC"). The control circuitry also includes
the cigarette sensor 57 for detecting the insertion of a cigarette
23 in the cigarette receiver 27 of the lighter 25, the puff sensor
45 for detecting a draw upon the inserted cigarette 23, the LCD
indicator 51 for indicating the number of puffs remaining on a
cigarette, the power source 35a and a timing network 197.
[0054] The logic circuit 195 may comprise any conventional circuit
capable of implementing the functions discussed herein. A
field-programmable gate array (e.g., a type ACTEL A1280A FPGA PQFP
160, available from Actel Corporation, Sunnyvale, Calif.) or a
micro controller can be programmed to perform the digital logic
functions with analog functions performed by other components. An
ASIC or micro-controller can perform both the analog and digital
functions in one component. Features of control circuitry and logic
circuitry similar to the control circuit 41 and logic circuit 195
of the present invention are disclosed, for example, in commonly
assigned, U.S. Pat. Nos. 5,388,594; 5,505,214; 5,591,368; and
5,499,636, all which are hereby incorporated by reference in their
entireties. Further details are also provided in commonly assigned
U.S. Pat. No. 6,040,560, hereby incorporated by reference in its
entirety.
[0055] In the preferred embodiment, eight individual heater
elements 37 are connected to a positive terminal of the power
source 35a and to ground through corresponding field effect
transistor (FET) heater switches 201-208. Individual (or selected)
ones of the heater switches 201-208 will turn on under control of
the logic circuit 195 through terminals 211-218, respectively,
during execution of a power cycle by the logic circuit 195. The
logic circuit 195 provides signals for activating and deactivating
particular ones of the heater switches 201-208 to activate and
deactivate the corresponding heater element 37 of the heater
fixture 39.
[0056] The logic circuit 195 cooperates with the timing circuit 197
to precisely execute the activation and deactivation of each heater
element 37 in accordance with a predetermined total cycle period
("T.sub.total") and to precisely divide each total cycle period
into a predetermined number of phases, with each phase having its
own predetermined period of time ("t.sub.phase"). In the preferred
embodiment, the total cycle period T.sub.total has been selected to
be 1.6 seconds (so as to be less than the two-second duration
normally associated with a smoker's draw upon a cigarette, plus
provision for margin) and the total cycle period T.sub.total is
divided preferably into two phases, a first phase having a
predetermined time period ("t.sub.phase 1") of 1.0 seconds and a
second phase having a predetermined time period ("t.sub.phase 2")
of 0.6 seconds. The total cycle period T.sub.total the total number
of phases and the respective phase periods are parameters, among
others, that are resolved in accordance with the teachings which
follow for establishing within the control circuit 41, a capacity
to execute a power cycle that precisely duplicates a preferred
thermal interaction ("thermal profile" or "thermo-histogram")
between the respective heater element 37 and adjacent portions of
the cigarette 23. Additionally, once the preferred thermo-histogram
is established, certain parameters (preferably, duty cycles within
each phase) are adjusted dynamically by the control circuit 41 so
as to precisely duplicate the predetermined thermo-histogram with
every power cycle throughout the range of voltages v.sub.in
encompassed by the aforementioned battery discharge cycle.
[0057] The puff-actuated sensor 45 supplies a signal to the logic
circuit 195 that is indicative of smoker activation (i.e., a
continuous drop in pressure or air flow over a sufficiently
sustained period of time). The logic circuit 195 includes a
debouncing routine for distinguishing between minor air pressure
variations and more sustained draws on the cigarette to avoid
inadvertent activation of heater elements in response to errant
signal from the puff-actuated sensor 45. The puff-actuated sensor
45 may include a piezoresistive pressure sensor or an optical flap
sensor that is used to drive an operational amplifier, the output
of which is in turn used to supply a logic signal to the logic
circuit 195. Puff-actuated sensors suitable for use in connection
with the smoking system include a Model 163PC01D35 silicon sensor,
manufactured by the MicroSwitch division of Honeywell, Inc.,
Freeport, Ill., or a type NPH-5-02.5G NOVA sensor, available from
Lucas-Nova, Fremont, Calif., or a type SLP004D sensor, available
from SenSym Incorporated, Sunnyvale, Calif.
[0058] The cigarette sensor 57 is located at the cigarette receiver
27 and supplies a signal to the logic circuit 195 that is
indicative of insertion of a cigarette 23 in the lighter 25.
Optionally a second sensor may be located adjacent the stop 183 so
as to determine whether the cigarette has been fully inserted into
the receiver 27.
[0059] In order to conserve energy, it is preferred that the
puff-actuated sensor 45 and the cigarette sensor 57 be cycled on
and off at low duty cycles (e.g., from about a 2 to 10% duty
cycle). For example, it is preferred that the puff actuated sensor
45 be turned on for a 1 millisecond duration every 10 milliseconds.
If, for example, the puff actuated sensor 45 detects pressure drop
or air flow indicative of a draw on a cigarette during four
consecutive pulses (i.e., over a 40 millisecond period), the puff
actuated sensor sends a signal through a terminal 221 to the logic
circuit 195. The logic circuit 195 then sends a signal through an
appropriate one of the terminals 211-218 to turn an appropriate one
of the FET heater switches 201-208 ON.
[0060] Similarly, the cigarette sensor 57 is preferably turned on
for a 1 millisecond duration every 10 milliseconds. If, for
example, the cigarette sensor 57 detects four consecutive reflected
pulses, indicating the presence of a cigarette 23 in the lighter
25, the light sensor sends a signal through terminal 223 to the
logic circuit 195. The logic circuit 195 then sends a signal
through terminal 225 to the puff-actuated sensor 45 to turn on the
puff-actuated sensor. The logic circuit 195 also sends a signal
through terminal 227 to the indicator 51 to turn it on. The
above-noted modulation techniques reduce the time average current
required by the puff actuated sensor 45 and the cigarette sensor
57, and thus extend the life of the power source 37.
[0061] The logic circuit 195 includes a PROM (programmable
read-only memory) 301, which includes preferably at least two data
bases or "look-up tables" 302 and 304, and optionally, a third data
base (look-up table) 306 and possibly a fourth lookup table 307.
Each of the look-up tables 302, 304 (and optionally 306, 307)
converts a signal indicative of battery voltage v.sub.in to a
signal indicative of the duty cycle ("dc.sub.1" for the first phase
and "dc.sub.2" for the second phase) to be used in execution of the
respective phase of the immediate power cycle. Third and fourth
look-up tables 306 and 307 function similarly.
[0062] Upon initiation of a power cycle, the logic circuit receives
a signal indicative of battery voltage v.sub.in, and then
references the immediate reading v.sub.in to the first lookup table
302 to establish a duty cycle dc for the initiation of the first
phase of the power cycle. The first phase is continued until the
timing network 197 provides a signal indicating that the
predetermined time period of the first phase (t.sub.phase 1) has
elapsed, whereupon the logic circuit 195 references v.sub.in and
the second look-up table 304 and establishes a duty cycle dc.sub.2
for the initiation the second phase. The second phase is continued
until the timing network 197 provides a signal indicating that the
predetermined time period of the second phase (t.sub.phase 2) has
elapsed, whereupon the timing network 197 provides a shut-off
signal to the logic circuit 195 at the terminal 229. Optionally,
the logic circuit 195 could initiate a third phase and establish a
third duty cycle dc.sub.3, and the shut-off signal would not be
generated until the predetermined period of the third phase
(t.sub.phase 3) had elapsed. A similar regimen could optionally be
established with a fourth phase (t.sub.phase 4). The present
invention could be practiced with additional phases as well.
[0063] Although the present invention can be practiced by limiting
reference to the look-up tables to an initial portion of each phase
to establish a duty cycle to be applied throughout the substantial
entirety of each phase, a refinement and the preferred practice is
to have the logic circuit 195 configured to continuously reference
v.sub.in together with the respective look-up tables 302, 303, 306
and 307 so as to dynamically adjust the values set for duty cycles
in response to fluctuations in battery voltage as the control
circuit progresses through each phase. Such device provides a more
precise repetition of the desired thermo-histograrn.
[0064] Other timing network circuit configurations and logic
circuits may also be used, such as those described in the commonly
assigned, U.S. Pat. Nos. 5,388,594; 5,505,214; 5,591,368;
5,499,636; and 5,372,148, all which are hereby incorporated by
reference in their entireties.
[0065] During operation, a cigarette 23 is inserted in the lighter
25 and the presence of the cigarette is detected by the cigarette
sensor 57. The cigarette sensor 57 sends a signal to the logic
circuit 195 through terminal 223. The logic circuit 195 ascertains
whether the power source 35a is charged or whether the immediate
voltage is below an acceptable minimum v.sub.in min. If, after
insertion of a cigarette 23 in the lighter 25, the logic circuit
195 detects that the voltage of the power source 35a is too low,
below v.sub.in min, the indicator 51 blinks and further operation
of the lighter will be blocked until the power source 35a is
recharged or replaced. Voltage of the power source 35a is also
monitored during firing of the heater elements 37 and the firing of
the heater elements 37 is interrupted if the voltage drops below a
predetermined value.
[0066] If the power source 35a is charged and voltage is
sufficient, the logic circuit 195 sends a signal through terminal
225 to the puff sensor 45 to determine whether a smoker is drawing
on the cigarette 23. At the same time, the logic circuit 195 sends
a signal through the terminal 227 to the indicator 51 so that the
LCD will display the digit "8", reflecting that eight puffs are
available.
[0067] When the logic circuit 195 receives a signal through
terminal 221 from the puff-actuated sensor 45 that a sustained
pressure drop or air flow has been detected, the logic circuit 195
sends a signal through terminal 231 to the timer network 197 to
activate the timer network, which then begins to function phase by
phase in the manner previously described. The logic circuit 195
also determines, by a downcount routine, which one of the eight
heater elements is due to be heated and sends a signal through an
appropriate terminal 211-218 to turn an appropriate one of the FET
heater switches 201-208 ON. The appropriate heater stays on while
the timer runs.
[0068] When the timing network 197 sends a signal through terminal
229 to the logic circuit 195 indicating that the timer has stopped
running, the particular ON FET heater switch 211-218 is turned OFF,
thereby removing power from the particular heater element 37. The
logic circuit 195 also downcounts and sends a signal to the
indicator 51 through terminal 227 so that the indicator will
display that one less puff is remaining (e,g., "7", after the first
puff). When the smoker next puffs on the cigarette 23, the logic
circuit 195 will turn ON another predetermined one of the FET
heater switches 211-218, thereby supplying power to another
predetermined one of the heater elements. The process will be
repeated until the indicator 51 displays "0", meaning that there
are no more puffs remaining on the cigarette 23. When the cigarette
23 is removed from the lighter 25, the cigarette sensor 57
indicates that a cigarette is not present, and the logic circuit
195 is reset.
[0069] Other features, such as those described in U.S. Pat. Nos.
5,505,214; 5,388,594; and 5,372,148 which are incorporated by
reference, may be incorporated in the control circuitry 41 instead
of or in addition to the features described above. For example, if
desired, various disabling features may be provided. One type of
disabling feature includes timing circuitry (not shown) to prevent
successive puffs from occurring too close together, so that the
power source 35a has time to recover. Another disabling feature
includes means for disabling the heater elements 37 if an
unauthorized product is inserted in the heater fixture 39. For
example, the cigarette 23 might be provided with an identifying
characteristic that the lighter 25 must recognize before the
heating elements 37 are energized.
[0070] Referring now to FIG. 6, the cigarette 23, as constructed in
accordance with the preferred embodiment of the present invention,
comprises a tobacco rod 60 and a filter tipping 62, which are
joined together with tipping paper 64. During manufacture of the
cigarette, perforation holes 263 can be provided in one or more
locations in the outer surface of the tobacco rod 60.
[0071] The partially-filled, filter cigarette 23 preferably has an
essentially constant diameter along its length and, which like more
traditional cigarettes, is preferably between approximately 7.5 mm
and 8.5 mm in diameter so that the smoking system 21 provides a
smoker a familiar "mouth feel". In the preferred embodiment, the
cigarette 23 is approximately 62 mm in overall length, thereby
facilitating the use of conventional packaging machines in the
packaging of the cigarettes 23. The combined length of the
mouthpiece filter 94 and the free-flow filter 92 is preferably 30
mm. The tipping paper preferably extends approximately 6 mm over
the tobacco rod 60. The total length of the tobacco rod 60 is
preferably 32 mm. Other proportions, lengths and diameters may be
selected instead of those recited above for the preferred
embodiment.
[0072] The tobacco rod 60 of the cigarette 23 preferably includes a
tobacco web or mat 66 which has been folded into a tubular
(cylindrical) form.
[0073] An overwrap 71 intimately enwraps the tobacco web 66 and is
held together along a longitudinal seam as is common in
construction of more traditional cigarettes. The overwrap 71
retains the tobacco web 66 in a wrapped condition about a free-flow
filter 74 and a tobacco plug 80.
[0074] Preferably, the cigarette overwrap paper 71 is wrapped
intimately about the tobacco web 66 so as to render external
appearance and feel of a more traditional cigarette. It has been
found that a better tasting smoke is achieved when the overwrap
paper 71 is a standard type of cigarette paper, preferably a flax
paper of approximately 20 to 50 CORESTA (defined as the amount of
air, measured in cubic centimeters, that passes through one square
centimeter of material, e.g., a paper sheet, in one minute at a
pressure drop of 1.0 kilopascal) and more preferably of about 30 to
45 CORESTA, a basis weight of approximately 23 to 35 grams per
meter squared (g/m.sup.2) and more preferably about 23 to 30
g/m.sup.2, and a filler loading (preferably calcium carbonate) of
approximately 23 to 35% by weight and more preferably 28 to 33% by
weight. The overwrap paper 71 preferably contains little or no
citrate or other burn modifiers, with preferred levels of citrate
ranging from 0 to approximately 2.6% by weight of the overwrap
paper 71 and more preferably less than 1%.
[0075] The tobacco web 66 itself preferably comprises a base web 68
and a layer of tobacco material 70 located along the inside surface
of the base web 68. At the tipped end 72 of the tobacco rod 60, the
tobacco web 66 together with the overwrap 71 are wrapped about the
tubular free-flow filter plug 74. The free-flow filter 74 (also
known in the art as "whistle-through" plugs) provides structural
definition and support at the tipped end 72 of the tobacco rod 60
and permits aerosol to be withdrawn from the interior of the
tobacco rod 60 with a minimum pressure drop. The free-flow filter
74 also acts as a flow constriction at the tipped end 72 of the
tobacco rod 60, which is believed to help promote the formation of
aerosol during a draw on the cigarette 23. The free-flow filter is
preferably at least 7 millimeters long to facilitate machine
handling and is preferably annular, although other shapes and types
of low efficiency filters are suitable, including cylindrical
filter plugs.
[0076] At the free end 78 of the tobacco rod 60, the tobacco web 66
together with the overwrap 71 are wrapped about a cylindrical
tobacco plug 80. Preferably, the tobacco plug 80 is constructed
separately from the tobacco web 66 and comprises a relatively short
column of cut filler tobacco that has been wrapped within and
retained by a plug wrap 84.
[0077] Preferably the tobacco plug 80 is constructed on a
conventional cigarette rod making machine wherein cut filler
(preferably blended) is air formed into a continuous rod of tobacco
on a traveling belt and entrapped with a continuous ribbon of plug
wrap 84 which is then glued along its longitudinal seam and heat
sealed. In accordance with the preferred embodiment of the present
invention, the plug wrap 84 is preferably constructed from a
cellulosic web of little or no filler, sizing or burm additives
(each at levels below 0.5% weight percent) and preferably little or
no sizing. Preferably, the tobacco plug wrap 84 has a low basis
weight of below 15 grams per meter squared and more preferably
about 13 grams per meter squared. The tobacco plug wrap 84
preferably has a high permeability in the range of about 20,000 to
35,000 CORESTA and more preferably in the range of about 25,000 to
35,000 CORESTA, and is constructed preferably from soft wood fiber
pulp, abaca-type cellulose or other long fibered pulp. Such papers
are available from Papierfabrik Schoeller and Hoescht GMBH,
Postfach 1155, D-76584, Gernsback, GERMANY; another paper suitable
for use as the plug wrap 84 is the paper TW 2000 from DeMauduit of
Euimperle FRANCE, with the addition of carboxy-methyl cellulose at
a 2.5 weight percent level.
[0078] The tobacco rod making machine is operated so as to provide
a tobacco rod density of approximately 0.17 to 0.30 grams per cubic
centimeter (g/cc), but more preferably in a range of at least 0.20
to 0.30 g/cc and most preferably between about 0.24 to 0.28 g/cc.
The elevated densities are preferred for the avoidance of loose
ends at the free end 78 of the tobacco rod 60. However, it is to be
understood that the lower rod densities will allow the tobacco
column 82 to contribute a greater proportion of aerosol and flavor
to the smoke. Accordingly, a balance must be struck between aerosol
delivery (which favors a low rod density in the tobacco column 82)
and the avoidance of loose-ends (which favors the elevated ranges
of rod densities).
[0079] The tobacco column 82 preferably comprises cut filler of a
blend of tobaccos typical of the industry, including blends
comprising bright, burley and oriental tobaccos together with,
optionally, reconstituted tobaccos and other blend components,
including traditional cigarette flavors. However, in the preferred
embodiment, the cut filler of the tobacco column 84 comprises a
blend of bright, burly and oriental tobaccos at the ratio of
approximately 45:30:25 for the U.S. market, without inclusion of
reconstituted tobaccos or any after cut flavorings. Optionally, an
expanded tobacco component might be included in the blend to adjust
rod density, and flavors may be added.
[0080] The continuous tobacco rod formed as described above is
sliced in accordance with a predetermined plug length for the
tobacco plug 80. This length is preferably at least 7 mm in order
to facilitate machine handling. However, the length may vary from
about 7 mm to 25 mm or more depending on preferences in cigarette
design which will become apparent in the description which follows,
with particular reference to FIG. 7.
[0081] As a general matter, the length of the tobacco plug 80 is
preferably set relative to the total length of the tobacco rod 60
such that a void 91 is defined along the tobacco rod 60 between the
free-flow filter 74 and the tobacco plug 80. The void 91
corresponds to an unfilled portion of the tobacco rod 60 and is in
immediate fluid communication with the tipping 62 through the free
flow filter 74 of the tobacco rod 60.
[0082] Referring particularly to FIG. 6, the length of the tobacco
plug 80 and its relative position along the tobacco rod 60 is also
selected in relation to features of the heater elements 37. When a
cigarette is properly positioned against a stop 182 within the
lighter 25, a portion 93 of each heater element 37 will contact the
tobacco rod 60 along a region of the tobacco rod 60. This region of
contact is referred to as a heater footprint 95. The heater
footprint 95 (as shown with a double arrow in FIG. 2) is not part
of the cigarette structure itself, but instead is a representation
of that region of the tobacco rod 60 where the heater element 37
would be expected to reach operative heating temperatures during
smoking of the cigarette 23. Because the heating elements 37 are a
fixed distance 96 from the stop 182 of the heater fixture, the
heater foot print 95 consistently locates along the tobacco rod 60
at the same predetermined distance 96 from the free end 78 of the
tobacco rod 60 for every cigarette 23 that is fully inserted into
the lighter 25.
[0083] Preferably, the length of the tobacco plug 80, the length of
the heater footprint 95 and the distance between the heater
footprint 95 and the stop 182 are selected such that the heater
footprint 95 extends beyond the tobacco plug 80 and superposes a
portion of the void 91 by a distance 98. The distance 98 by which
the heater footprint 95 superposes the void 91 (the unfilled
portion of the tobacco rod 60) is also referred to as the
"heater-void overlap" 98. The distance by which the remainder of
the heater footprint 95 superposes the tobacco plug 80 is referred
to as the "heater-filler overlap" 99.
[0084] The tipping 62 preferably comprises a free-flow filter 92
located adjacent the tobacco rod 60 and a mouthpiece filter plug 94
at the distal end of the tipping 62 from the tobacco rod 60.
Preferably the free-flow filter 92 is tubular and transmits air
with very little pressure drop. Other low efficiency filters of
standard configuration could be used instead, however. The inside
diameter for the free flow filter 92 is preferably at or between 2
to 6 millimeters and is preferably greater than that of the free
flow filter 74 of the tobacco rod 60.
[0085] The mouthpiece filter plug 94 closes off the free end of the
tipping 62 for purposes of appearance and, if desired, to effect
some filtration, although it is preferred that the mouthpiece
filter plug 94 comprise a low efficiency filter of preferably about
15 to 25 percent efficiency.
[0086] The free-flow filter 92 and the mouthpiece filter plug 94
are preferably joined together as a combined plug with a plug wrap
101. The plug wrap 101 is preferably a porous, low weight plug wrap
as is conventionally available to those in the art of cigarette
making. The combined plug is attached to the tobacco rod 60 by the
tipping paper 64 of specifications that are standard and
conventionally used throughout the cigarette industry. The tipping
paper 64 may be either cork, white or any other color as decorative
preferences might suggest.
[0087] Preferably, a cigarette 23 constructed in accordance with
the preferred embodiment has an overall length of approximately 62
mm, of which 30 mm comprises the combined plug of the tipping 62.
Accordingly, the tobacco rod 60 is 32 mm long. Preferably, the
free-flow filter 74 of the tobacco rod 60 is at least 7 mm long and
the void 91 between the free-flow filter 74 and the tobacco plug 80
is preferably at least 7 mm long. In the preferred embodiment, the
heater foot print 95 is approximately 12 mm long and located such
that it provides a 3 mm heater-void overlap 98, leaving 9 mm of the
heater foot print 95 superposing the tobacco plug 80.
[0088] It is to be understood that the length of the void 91, the
length of the tobacco plug 80, and the distribution of the
perforation holes 263 may be adjusted to facilitate manufacturing
and more importantly, to adjust the smoking characteristics of the
cigarette 23, including adjustments in its taste, draw and
delivery. The pattern of holes 263, the length of the void 91 and
the amount of heater-filler overlap (and heater-void overlap) may
also be manipulated to adjust the immediacy of response, to promote
consistency in delivery (on a puff-to-puff basis as well as between
cigarettes) and to control condensation of aerosol at or about the
heaters.
[0089] In the preferred embodiment, the void 91 (the filler-free
portion of the tobacco rod 60) extends approximately 7 mm to assure
adequate clearance between the heater foot print 95 and the
free-flow filter 74. In this way, margin is provided such that the
heater foot print 95 does not heat the free-flow filter 74 during
smoking. Other lengths are suitable, for instance, if manufacturing
tolerances permit, the void 91 might be configured as short as
approximately 4 mm or less, or in the other extreme, extended well
beyond 7 mm so as establish an elongate filler-free portion along
the tobacco rod 60. The preferred range of lengths for the
filler-free portion (the void 91) is from approximately 4 mm to 18
mm and more preferably 5 to 12 mm.
[0090] In another embodiment, a cigarette 23 has an overall length
of approximately 68 mm, of which 36 mm comprises the combined plug
of the tipping 62. Accordingly, the tobacco rod 60 is 32 mm long.
Preferably, the free-flow filter 74 of the tobacco rod 60 is at
least 13 mm long and the void 91 between the free-flow filter 74
and the tobacco plug 80 is preferably at least 7 mm long.
[0091] Regardless of the length of the cigarette, the cigarette can
include filter material, e.g., the void space can contain filter
material such as activated carbon, flavored carbon, silica gel
particles, or other filtering material. Also, the controller can be
programmed to operate the heater fixture so as to warm the
cigarette upon insertion thereof into the EHCSS. For example, the
control circuitry can be operable to cause delivery of energy to
the heater blades (e.g., about 5-6 Joules) to thereby warm the
cigarette such that moisture moves from the wrapper into the
central portion of the cigarette.
[0092] During smoking of the cigarette, the controller preferably
activates one of the heating blades to apply heat to a heating zone
along the outer periphery of the cigarette. For example, the zone
can range in size from 3 to 25 mm.sup.2 as mentioned in commonly
assigned U.S. Pat. No. 5,750,964 incorporated herein by reference.
A preferred heating zone for a cigarette having a wrapper with an
ammonium containing compound filler therein has a length of 10 to
20 mm and covers an area of 10 to 20 mm.sup.2 and the preferred
amount of heat applied to the heating blade in accordance with a
programmed power cycle is 15 to 40 Joules, preferably 20 to 35
Joules. With such heating, the heating zone can be heated to a
temperature of up to 500.degree. C. and the tobacco mat can be
heated to a temperature of about 200 to 350.degree. C., preferably
220 to 320.degree. C. Due to resistance heating of the heater
blade, the temperature of the blade may be somewhat lower at each
longitudinal end thereof, e.g., the temperature of the blade may be
25 to 50.degree. C. higher in the central portion of the blade when
the blade reaches its maximum temperature.
[0093] It has been found that the controlled heating of the heated
blade in combination with use of a cigarette wrapper having an
ammonium containing compound filler results in reduction in various
constituents of the tobacco smoke. A preferred ammonium containing
compound filler is ammonium magnesium phosphate (AMP) and the
heater blade is preferably supplied 20 to 35 Joules of energy
according to the aforementioned programmed power cycle when
activated by the controller. A preferred temperature of the tobacco
mat along the heating zone during heating of a heater blade is 200
to 400.degree. C., more preferably 220 to 320.degree. C. Also, it
is preferred that the cigarette include laser perforations and/or
mat holes as discussed above. Moreover, it is preferred that the
EHCSS occlude the free end of the cigarette to minimize flow of
ambient air into the free end and include an air swoop to direct
ambient air towards the laser perforations and/or mat holes as
discussed above.
[0094] According to the invention, the EHCSS is used to smoke a
cigarette wherein the cigarette wrapper includes an ammonium
containing compound filler such as magnesium ammonium phosphate
(AMP), preferably the monohydrate form of AMP in an amount
effective to reduce the contents of a plurality of gaseous
components in the smoke produced by combustion/pyrolysis of the
cigarette. Compared to cigarette paper wherein calcium carbonate is
the sole filler, when the ammonium containing compound filler is
used it is possible to reduce the amounts of gas constituents in
the mainstream smoke of the smoking system, such constituents
including aldehydes (e.g., formaldehyde, acetaldehyde,
propionaldehyde), carbon monoxide, 1,3-butadiene, isoprene,
acrolein, acrylonitrile, hydrogen cyanide, o-toluidine,
2-naphtylamine, nitrogen oxide, benzene, NNN, phenol, catechol,
benz(a)anthracene, benzo(a)pyrene, etc.
[0095] FIGS. 7-8 show results of relative measurements of tobacco
smoke constituents produced in an EHCSS using cigarettes with
ammonium containing compound filler (i.e., the monohydrate form of
AMP) compared to CaCO.sub.3 filler. As shown, the general levels of
smoke constituents such as TPM, tar, and water are substantially
the same for both cigarettes whereas nicotine and acrolein levels
are reduced somewhat and the remaining constituents are
dramatically reduced for the ammonium containing compound filler.
One constituent which was not reduced in the tests was
2-nitropropane. Also, while not shown in FIGS. 7-8, the ammonia
levels in the tobacco smoke are elevated for ammonium containing
compound filler.
[0096] When compared to a conventional light standard reference
cigarette (1R4F), the electrically heated cigarette according to
the invention with ammonium magnesium phosphate (AMP) incorporated
into the paper wrapper yields approximately 90% lower
concentrations of carbon monoxide, 1,3-butadiene, acrylonitrile,
benzene, and benzo(a)pyrene on a per mg TPM basis compared to the
conventional light standard reference cigarette (1R4F). Aldehydes
were 40% lower (one exception, formaldehyde, was 75% higher).
[0097] The wrapper according to the invention can be manufactured
by conventional papermaking processes wherein a filler, of low
solubility, effective in reducing the content of gaseous components
in smoke is added either by itself or as a mixture with other
filler materials to an aqueous slurry containing cellulosic
material.
[0098] The monohydrate form of AMP (MgNH.sub.4PO.sub.4.xH.sub.2O
wherein x is 1) has a low solubility in water so as to be
compatible with conventional papermaking processes, e.g., the
filler is substantially insoluble in an aqueous dispersion
containing ingredients of the paper such as flax, etc. That is, the
ammonium containing compound filler is stable enough in a
papermaking process to survive intact as filler in the final paper
product. This includes sufficient thermal stability to survive the
drying steps in the papermaking process. The ammonium containing
compound filler also evolves ammonia during the smoking process
while decreasing the content of gaseous constituents such as low
molecular weight aldehydes in smoke. The monohydrate form of AMP
(mono-AMP) is also known as dittmarite and can be derived from raw
ingredients or converted into the mono-form from the hexavalent
form known as struvite. The mono-AMP can be provided with a range
of surface areas, a range of particle sizes (mostly in the micron
range), possess appropriate opacity, have low solubility in water
(required for papermaking), and possess other properties that are
considered desirable in fillers for cigarette papers. For purposes
of a filler for cigarette paper, the monoAMP preferably has a
particle size below 25 .mu.m, more preferably below 10 .mu.m.
[0099] When used as filler in the fabrication of wrappers for
cigarettes of an EHCSS, a preferred amount of the ammonium
containing compound filler is equal to about 10% to about 60% of
the final wrapper weight, more preferably about 20% to about 50% by
weight. This percentage is referred to as the filler loading.
Although the ammonium containing compound filler is preferably the
sole filler, it can be mixed with one or more other fillers in the
paper. In the case of mixtures, a portion, e.g., up to 60% by
weight, of the filler loading can comprise one or more inorganic
carbonate, inorganic hydroxide, inorganic oxide, or inorganic
phosphate. Examples of such fillers include, e.g., calcium
carbonate, magnesium hydroxide, magnesium oxide, magnesium
carbonates, and titanium dioxide as well as other fillers known in
the art.
[0100] The wrappers containing the ammonium containing compound
filler can have a basis weight of between about 15 to about 75
grams per square meter and can have a porosity of between about 2
to about 200 cubic centimeters per minute per square centimeter as
measured by the CORESTA method ("CORESTA units"). A preferred basis
weight is between about 20 to about 50 grams per square meter and
the most preferred porosity is between about 10 to about 110
CORESTA units. A more preferred basis weight is between about 25 to
about 30 grams per square meter and the most preferred porosity is
between about 25 to about 50 CORESTA units.
[0101] Burn additives such as alkali metal salts of carboxylic
acids or phosphoric acids can be applied to the wrapper to adjust
or control the burn rate of the resulting smoking article. For
example, burn additives can be applied in amounts ranging from
about 2% to about 15% by weight of the wrapper. Examples of burn
additives include sodium fumarate, sodium citrate, potassium
citrate, potassium succinate, potassium monohydrogen phosphate, and
potassium dihydrogen phosphate.
[0102] To prepare wrappers containing the ammonium containing
compound filler, conventional cigarette papermaking procedures can
be used with the inclusion of an ammonium-containing compound
filler in place of or in combination with a conventional cigarette
paper filler such as calcium carbonate. The paper wrappers may be
made from flax, wood pulp, or other plant fibers. In addition, the
paper wrappers may be a conventional one wrapper construction, a
multiwrapped construction or a multilayer single wrap
construction.
[0103] If the ammonium containing compound filler comprises the
monohydrate form of magnesium ammonium phosphate, it can be
incorporated in the cigarette paper as follows. For instance, a
slurry of the monohydrate form of magnesium ammonium phosphate can
be mixed with feedstock of a paper making machine or the slurry can
be dried to particle form (e.g., powder) and such powder can be
incorporated in the paper making feedstock. In order to prevent the
magnesium ammonium phosphate in the monohydrate form from
transforming back to the hexahydrate form, it is desirable to
maintain the slurry above 55.degree. C. until it is incorporated
directly in feedstock (preferably heated above 60.degree. C.) of
the paper making machine or until the slurry is dried into particle
form such as by flash drying which removes the water from the
slurry under elevated temperature conditions. Once dry, the
monohydrate form of the magnesium ammonium phosphate remains
stable. The magnesium ammonium phosphate preferably has a particle
size in the range of approximately 2 .mu.m to 8 .mu.m, more
preferably in the range of 2 .mu.m to 4 .mu.m.
[0104] It is to be understood that the present invention may be
embodied in other specific forms and process the use without
departing from the spirit or essential characteristics of the
present invention. Thus, while the invention has been illustrated
and described in accordance with various preferred embodiments, it
is recognized that variations and changes may be made therein
without departing from the invention as set forth in the
claims.
* * * * *