CA 02218595 1997-10-17
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CIGARETTE AND EEATER FOR QSE IN AN ELECTRICAL
SMOKING SYSTEM
y
T~'i of -d OT Tn~sont i Or
The p=esent invention relates generally to electric=1
sme'.ting systems, and in part_cular to cigarettes adapted to
coeper~te w'_th electrical lighters of elect=ical smoking
SyStemS, a~?.~.~. t0 a heater f:Jr uSc in elCtriCZl Si110king
SVS te:T.:S .
3ack~~-ound cT the Tnv~n~-cn
Tradi_ional cigarett=s del_ver flavor and aroma to the
smoker as a resul t of combustior_, during wh is h a m=ss of
cor.;oustibl °_ material, D=i=!CiDa~ 1 y tObaCCO, 1S COm~y~.uSte3 ct
te-pe=~tures which often, exceeds 800° C durinc a pt:ff. =ear
is drawn t==ough cn adjacent mass of tobacco by drawing on
~° mOUth a nd. During heating, in e~f' Clent OX~dct~0l1 Of the
t__.
cos,:oustibl= material rel_=ses var'_ous gaseous combustion
produces a_-_d distillates =rom the tobacco. As these gaseous
products G=a drawr_ through the cigarette, th ey cool ar_d
condense t:, form an aerosol which provides the tastes and
aromas associated wit'_z s.-..oking.
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_=aditional cigarettes have various perceived
arawbac.'ts associated with them. Or_e oz these is the
Droduc=ion oz sidestream smoke during smoldering between
pu=fs which may be objectionable to non-smokers. Once lit,
they m=_st be fully consumed or be discarded. Pe-lighting a
tradi~=oral cigarette is possible but is usually an
unat===ctive preposition to a discerning smoke= for
subjec=ive reasor_s (flavor, taste, odor) .
1 v i v v r i i r~-y~
rz a t_rnat_ve to th_ mor_ t_adit_onal c_ga_____s
incluces those in which the combustible mate=ial itse'_= does
not i=sel~ release the tobacco aerosol. Such s;aok'_-c
antic==s may comprise a combustible, CZ=bOnaCeOLS he===ng
eleme=_ (~e=t sOU=Ce) IOCaCe~ at Cr abOLt One e'~ C. C-a
smoki_-_g ar ticl a an d a be3 oz tobacco-lacer a 1 emezts _c.._tec
ad) aC~a tile a~orementioned he.--..ring °~ e:~t~=It . =' .°_
i~c_..~I1C
_c _,
el eme= t is ignit=d with a match or cigar=rte l i _'.'.~._te'- and
ig ra- 3 heat c~=er=red by
when a smoker draws upon the c_ a___t_,
tile h=ating element is communicated to the beoz tobacco
IadeT eleme~ts so as to cause tze bed to release a tobacco
r
aerosol. While this type oL smoking device prccuces ='ttle
or no sidestream smoke, it still generates procucts e.
combus~ior_ a. the heat source, and once its heat sour=a is
ignit=~, it is not readily snu==ed nor Luture use i~ a
pract_cal sense.
.n both the more cor_ventional and carbon heated
devic=s dose=ibed above, combustion takes plat°_ dur'_-c the..
use. This process naturally gives rise to maTy by-p ..ducts
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as the combust=ed m.:rterial brf>.a.~s down and interacts with the
surrounding atmosplm.re .
Commonly assi~tn.e>d L).5. Fpa~:errt:s Nos. >, 666, 978,
5,505,214, 5,093,8'x4, ~~,225,~~9u, 5,060,671 and 5,09,921
disclose various h~=>~~~- ~ng elements and flazTor generating
art.ides which sig:rri.:f-scantly reduce sidest~ream smoke while
permitting thE_~ smol:.ex to se Lec~ ively suspend and reinitiate
smoking. However r:h.~: cigaret.t« articles disclosed in these
patents are not ve:~:~~.e durable arid may collapse, tear or break
from extended or hea~~ey ha.nd:l:i.ng. Im cert~iin circumstances,
these prior cigaret::t:cps ma.y aYu~ah a:; they are even weaker and
may tear or break <m~ t=.hey are removed .frorn the lighter.
The aforement. i.oned, United States pat;ent:s Nos.
5, 666, 978 and 5, 38t:~, 594 descli ibe an electi:-ical smoking
system including a rm~~vel. elec~t:r~ically powered lighter and a
novel cigarett:.e th<.rt~ cooper.~t:es with the -~ighter. The
preferred embodiment: of the lighter includes a plurality of
metallic ;~erpentinc:a he a.t.ers c.~itposed in a configuration that
slidingly receives a tobacc;~ r~od portion of the cigarette.
The preferred embodiment-~ ~_~f the cigarette in U.S.
patent No.. 5, E~66, 9'78 and also ~:ii~;c:losed in EP-A-0, 615, 411
comprises a tobacc~::>--_La.den tu~>ular carrier, a cigarette
paper overwrapped ::rb~c~ut the t:ubul.ar carrier, an
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arrangement of flow-thrcugh filter alugs at a mouthpiece end
of the carrier and a filter plug at the free (distal) end of
the carrier. The cigarette and the lighter are configured
such that when the cigarette is inserted into the lighter
and as individual heaters are activated for each puff,
localized char=ing occurs at snots about the cigarette in
the locality where each heater was bearing against the
cigarette (hereinafter refer=ed to as a "heater footprint").
Once all the heaters have been activated, these charred
spots are closely spaced from one mother and encircle a
Central DOrtlOT_'! Of th° Carr_== DOrC_On Of the cigarette.
Depending on the maxim~:;,i tempo=atures and total
energi°S dellV~r'd at the h°at~rS, ~h°_ Charred sDOCS
.~:anifest mcre Khan mere discoiorat'_or_s oz the cigarette
paper. In most appl'_cat_ons, the c=_=ring will create at
least minute be=aks in the cicar~tt= paper ar_d the
u_-iderlying carrier material, which breaks tends to
mechanically weaken the ciga='tte. .or the cigar_tte to be
withdrawn from the li liter the cha=se
g . d spots must be at
least partially slid past the heat==s. In aggravated
circumstances, such as when the cigarette is wet o. toyed
with or twisted, the cigaret~e may be prone to break or
leeve pieces upon its withdrawal from the lighter. Pieces
left in the lighter fixture can int===ere with the proper
cperatior_ of the light=_r and/or deliv_r an off-taste to the
smoke ef the next cicaY-errA r~ ,-~,a .. _~~_ L___,__
______ __~~-~-..v. ii ...11r.. L.1~G1..-'..I.LC Dr$GK.S J.~ twO
while being withdrawn, the smoker may be faced not only with
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the frustration of i-~ril-ed cigaret:te produ~:t, but also with
the prospect c>f c1-ear~ing debris from a clogged lighter
before he or she c<:~ru Een~c>y anothez- cigarefite.
The preferred f~mi>odi.me:nt: of the ciac~arette of Lt. S .
patent No. 5, C~66, 9?8, EP-A-0, 6~ 5,~E7_l. and iJ.S. Patent. No.
5, 388, 594 is essent,i,~ll.y a hollow tube bet=ween the falter
plugs at t;he mouth~.:.~ce end of the cigarette and thE~ plug at
the distal enci. T:In.:i..~s construction is bel. ieved to e~.evate
delivery t;o the smc:o:~er by provi.dinc~ suffi~;ient space into
which aerosol can ~:~~re>:l.ve of f the carrier with minimal
impingement and coiocaensat:ion of t;he aerosol on any nearby
surfaces.
Several propc;:~a_l..s have been advanced which
significantly redu::~e undesired sidestream smoke while
permitting the smo',.-,.c~ay- t=o suspend smoking of the article for
a desired period a~~:~c:i then t<: resume smoking. For e~:ample,
commonly assir.~ned (J. S. Patents No:~. 5, 093, '394; 5, 225, 498;
5, 060, 671 and 5, 09:x, ~~~r?i disclose various .;zeating elE:ments
and flavor gene ratirnct systems . EP--A-0, 615, 411 and LJ. S.
Patent No. 5, :388, 5:a<1: di:~c:lose an electrical smoking system
having heaters whi~:~ll ar_e actuated upon se:c~sing of a draw by
control anal logic ~.:::i-:r-cuit:ry. The heaters are preferably a
relatively thin sery oentine st=ruct;ure to transfer adequate
amounts o:E heat to t:tie cigarette and is lightweight.
Althc:~ugh then= crevices and heaters overcome the
observed problems <~.rm~ achieve the stated objectives, many
embodiments are sul;>:j ce::~t= t=o mechanical. weakening and possible
failure due to strcJ~:~es indu.r_ed by :inserting and removing
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the cylincrical tobacco mediu:a and also by adjust_ng or
toying wi=h the inser_ed cigarette.
Fur. her, u_T~desired electrical s:~orts can occur i= the
shape oz a heater assembly is altered, e.g., by adjusting or
i
toying with the inserted cigarette.
Also, the electr_cal smok_ng systems employ
electrica_ly resistive heaters which have necessitated
relatively compl_x electrical connections w~~ich can be
disturbed by insertio:: a_nd r~:noval c~ the c=garette.
Whe_~_ we included cut tiller with the hollow structure
oz the c=CarStt°_ 1n =_ T-0, 6=~, c~ ~ , _,_ Wa5 diSCOV~red t=. hat
SLlCn ClCar°tte5 wLle_~. ~'.~~ly L~.1 ~ ed Wit_1 Cut ~1~ ler
tObaCCO
te~ideCl tC ODera~.'-.. aG?~,~a rely in an e.°Ctri Cal 11C~ t°_r
~Or
the i=rSt Several pu==S. Th°r°3Lter, itS G°_1Ve=J WOLId
tend t0 tape. O.. . '~'~S Same pi °nOm°_ nOn WOL: l C t°
nG t0 OC,~_Llr
whe_~_ more traditional c'_garet~es wer. smok_d in Gn
electrical lighter sucz as to electr_cal l~chter disclosed
in ?P-A-0,61~,~?1.
Whe. le=t L~__1~ 1 °_.~., the :1011 OW Cigar°_W'~.°_
StrTrtC T'~e
tL- S OL
r
th° pre'crred erbOdimentS Oi LP-A-O,6lS,a?1 Were 81SO
somewhat ~-ulnerable to colla_se prom extreme or rough
handling.
The invention, in its various aspects, is d==fined by
the index=ndent claims annanced hereto.
A c_carette embcdy_ng aspects o. the present invention
has the a::vantace o~ co:.tai n_ng cut ~i 1 ler yet be'_ng
operable with co:a istency when smoked as part of an
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electrical smoking system.
A c'_carette embodying aspects oz the invention has the
~ advantage of containing cut fills=, and being adapted to
cooperate with an electrical lighter and render satisfying
"' levels of taste and delivery.
A c'_carette e:"bodying aspects of the present invention
has the advantage o. ir_cluding cut fills=, yet providing
improved consistency in delivery =rom pu=_ to cuff.
Cigarettes embodying aspects of the invention may be
read=ly r:anufactur=d and packed into at==active packaging.
Ciga=etteS ecr~~odyi=lg aspects OL t:?e lnvelalon may be
physically robust a=~d min=mize cc_-_der_sat_on and/or
filtratio~ of aerosol w=thin the cigare___ and/or the
licht_r. ~hey may further be res_stive to brea'.~cace during
th a w=thd=awal c= th a c_garette ==om the 1 i ght== then=of .
Ciga==ttes e~;:odying aspects of the press~~ invention
and suites for consumption with a lights= of ar_ electrical
smoking system, and may be less v-=lnerable to collapse or
breakage during rough handling by the cc=sumer.
Ciga=ettes er,:rodying aspects of the present invention
and suit=~ for consumption with a lights= of an electrical
smoking system may not be prone to collapse or breakage
during the manufacture or packing of the cigarette.
Cigarettes embodying aspects of the invention and
operative with an electrical lig',-=er may be co.~_ducive to
cost-effective methods of manufacture, even at production
speeds.
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:eaters embodying aspects or the invention may
generate smoke from a tobacco medium without sustained
combustion, may reduce the creation of undesired sidestream
smoke, may permit the smoker to suspend and resume use, and
may improve aerosol ge_~_eration within the smoking system. '
heater str~ctu=a embodying the invention may provide
a desi=ed nur.,ber o. pu==s and be straightforwardly modified
to change the nur,.ber and/or d~~ration of puffs provided
without sacri=ici.~.c subjective ~~;lities of the tobacco.
A heating e'_ement embodying the inventior_ may be
,- ; -, ~ o ,-
mechanically sui=able fo_ ~____tion and removal of a
cigar=tte.
n ~ o.._,-; - _ re ; ~-; -,g
_ z e__..___ca__y _ s_s~___ =eat__ embodyi ng spoors of
the invention may ~~ave simp_ified connecLior_s to an
associ_ted power s~::rce.
heati ng e? e:lent embodyi rg aspects of t~=_ invention
.may be mechanically stable durinc heating cycles.
embodiments c_-' the invention may minimize var_ation of
an ins=rface be~we=n tie heatinc element and the cigarette
to avoid changes =__ heat trar_sfer.
heater e.::oodying the invention may be more
economical to mane=act~~re.
One preferred e.~i.~.odiment provides a smoking system for
delivering a flavored tobacco r=spouse to a smoker. The
system includes a cigarette ar_d an electrically operated
lighter, which lichter includes a plurality of electrical
heaters, with eac oz the heaters being adapted to, either
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singularly or in concert, to thermally release a
predetermined cruant_ty of tobacco aerosol from the cigarette
upon its/t'_heir activation. The cigarette comprises a
tubular tobacco web, wherein a first portion of the tabular
' tobacco web is filled with a column of tobacco, preferably
in the fore of cut filler, and a second portion of the
tubular tobacco web is left tnfillec or hollow so as to
define a void in the tobacco column.
More particularly, the aforementior_ed c~carette
preferably comprises a tobacco rod =ormed f--om a tubular
tobacco web and a plug of tODGC.~.O IOCa.'.ed within the tubular
tobacco web. The tobacco roc is adapted to be s_idingly
receiv=d by an e_=ctrical ~'lE.ter __X.''.Llr~ such ___
at the
heats= elements locate alor_c=ide the tobacco _oc at a
lOCatiOn between tale fr°e enG a nd c~ ODDOSit~ a~Q Of the
tobacco roc. Dre~arably tile plug (or column) of tobacco
extends from the free end of t .e tobacco rod to a 1 ocation
that is spaced from the opposites end of the tobacco rod so
as to de=iae a void (or hollow port_on) ad~acezt the
ODDOSite e_~_d.
The relative dimensieTs of the cigarette aaa the
heater fixture of the lighter a=a dete=-mined such what upon
insertion of -the cigarette i..o the lighter, each heats=
will locate alongside the tc~acco rod at a precetermined
location along the tobacco rid and, preferably, such that
the longitudinal extent of contact between the heater and
the c=gore=to (hereinafter ~aeater footprint") superposes at
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least a portion of the aforementioned void a:-ld at least a
portion of tine plug of tobacco. In so doing, consistent and
satisfactory delivery is 'obtained when the cigarette is
electrically smoked, and condensation of tobacco aerosol at
or about the heater elements is reduced. '
In th a al ternative, t .e rel ati ve di me =sions of the
cigarette and t he heater f i xture of the 1 igtar ar a
determines such that upon i_-sertion of the cigaret~e '_nto
the lighter, each heater will locate alongsice the tcbaccO
rOd SLlCh that n= least SOm°, 1f nOt all ...~ th°_ hE=: er
fOOtDr?nt5 SLlpel'yCSe Only th°_ filled pOr.'_1012 Of t h°_
tObaCCO
rOC (OVer tile tL.LaCCO plug) . In such conf=~'~ratlOnS, the
i
void may sail! be empicyed to facilitate aerosc_ =orma=ion
ar_c to he_:, cool the smoke .
Pre=_=ably, a ciczrette gape= is wra=ped about t
o ~r a o ~_.- o " =eel
tt.bular tobacco W_b so cs to = ovid_ th_ apn_=_anc_ a__c _
Of the mores traCitl.Onal Cigarett= during handlinC by the
smoker
The tobacco web pre-erai~ly comprises a r-onwcven
tObaCCO bcSe web and a lays. Of tobacco ma=°rial lOC_Le'',~
along at least oe side or t=a tobacco base web.
The cigare~te are==rably also includes =filter tipping
at the afOrementiOned Op p051.ta end Of the tObaCCO rOd, W -7.Ch
compri ses a flow- through fil ter plug (also k_-_owr_ i n the art
as "whistle-through" plugs), a mouthpiece f_lter plug and
ti=ping paper at=aching the plugs to the tobacco roc.
Wher. a cicarette embodying the present invention is
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inserted into a lighter of an electrical smoking system, tine
cigaret_e regis~_rs against a stop located within the heat=r
fixture of the lighter (or at some eauivalent recistration)
so that the el=ctrical heating elements of the lighter.
locate consistently alongside tile cigarette at generally the
same location fo. each cigar=tte. As a puff is initiated,
at least one of the heaters of the lighter is _=sponsively
activated to heat the cigarette at the aforementioned
locati c:~ along t he tobacco rod. As a puff pros=esses, the
tobacco rod is h_=ted and aerosol is driven off _he tobacco
Web and the L=1!°=. Wher° ~° ~~ v - rir-
t___ h__t_r tootp_____ super roses
the ve'_d in the tobacco rod, tobacco aeroso_ is almost
immed~._t=ly ~°1 cased __.t0 the spaC° defined W~t~'11n the
unflll ~ d DOrt_On Of the tOL7aCC0 =Od and drawn DLit O~ the
m
cigaret=e. _he tobacco web contributes most of this
fraction of the total ae=osol delivered by the c_~arstte and
its imrediacy a believed to favorably affect the nature and
extent of the s.,.oker~s draw on the cigarette. Because of the
greater mass ef tobacco at tile filled portion of tile tobacco
rod, there is a slight delay in the release of aerosol from
where tale heats- footpr'_nt superposes the f?11e~ portion of
the rod. The aerosol which a driven off the fi-led portion
of the tobacco rod contributes an additional, domir_ating
flavor a:.ld character to the smoke.
A further aspect of the present invent_on is the
capacity to adjust delive=-y of a cigarette of a_-_ electrical
smokinc system, wherein the proportional amount of overlap
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betwee= the filled and u~-!f=!led portions of the tobacco rod
by th. heater footprint effects desired adjustments in
delive-y from one brand of cigarette to another or within ,
line ex_ensior_s of the same brand.
vet another aspect of the prese_nc invention is a
methcc of improving levels and consistency of delivery of
aerosc_ from a c_~a__tte op__ e-
~- r° gated wi th ar_ electronic heat
devic=, wherein the cigar_t=a has a f=ee end and an ODDC5It°_
end. ~he method comprises the stews of superpos_na a heater
footpr_nt over both a tobacco-filled porticr_ of the
Ci gar°=~e adjacent the _=~° end and ail L=!fi~ ~
°.". pC='..iCP C.
the Clgaret.'.° aGjaC°nt the ODDOS~te e'd, Wi_il=
sisult_neousiy -es_stiv=_v heatir_g a?ong the heater
=ootp=_nt and drawing or. t =a ci garett_ t b=ough the epp csit=
enc t _==eof .
_till another aspect .,_ the present invention is to
prcvic_ a fills= containing cigarette that is operative with
an el=ctrical lighter, which cigarette includes a tobacco
rod h_;ri ng a free-flow filt.r aid a fil 1er-free rod Aortic
adjace=t the free flow filter so as to promote consisten~
ae=osc_ production.
zothe= aspect of the present invention is
reinforced t~ibular tobacco web having flax or woos
cellu_osic fiber added to its base web so as to nrovice
addlt_.~.nal st=e_~_Cth. IIi t he al ternat?Ve, Ce11L1051C f1~'Je=
from tobacco stem feedstock may be included in the
compes_tion of the base web as a reinforcing age_-_t.
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Robustness of the cigarette is improved by the
i nclusier_. of cut filler within the confi nes of its tubular
' tobacco web so as to provide a cigarette which can better
w_thstanc handling, including handling by cigarette
rna_-iuf act ur ing machines and by consumer s .
A h==ter embodying i ent_on p_____ably
the nv ~ ,-o=o,.. coma,-ises
a suppor==ng hub and a plurality of oleo=rically resistive
h_=,.__ b_=des de=ini ng a
°_-~"~ - - re_ ptacle to receive an inserted
Cigare
t~_. Each blade comprises a first heater blade leg
r~a;rin~c- a =first end and a second end and extending at the
f_rst e..~_c =rom the supportir_g hub, a second heater b'._ade lea
~"v-ng C -~-rSt end and a Second e__~_d an d a ~T'~ ;
C..._~1e c t __~_g
s_c~ion _~ :necti
ng the secor_d end of the _irst lei ar_d tine
__=st e_-_c of the second lec. The second end of t'_-.__ second
1._..~, eXte= GS toward t_}'le SLIppCr tlng hub c .d 1.S a ~ ec'r i a l l y
C___
i_~_sulate~ therefrom. A resistive hen=ing circuit =s formed
to heat _he electrically resistive heat_r blade which in
turn hen=s the inserted cigarette. The first ar_d second
a'-'= S=pai ae.°_d by a gap t0 pe='m? t el7.trai amen t of ai r to
a'_~ in evolving flavor substances from the heated cigarette
upon draw=g by a smoker.
Embociments of the invention will now be desc=ibed, by
way of _xample, and with re~er~nce to the accomaar_ying
crawings, wherain:
Fic=. 1 and 2 are perspective views of an electronic
s;,;oking system in accordance with a preferred embodiment of
th a prose =_ invention;
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Fig. 3 is a breakaway perspective v=ew of a cigarette
engaged within the heat=r fixture of the smok'_ng system
shown in Fig. 1;
Fig. aA is a sectional side view or a cigarette
const=-acted in accordance with a preferred e:nbodi meat of the
present invention;
Fi g. a3 is a d.. ed
tail perspect'_ve view of the
cigarette shown in Fig. 4A, with cer~ain components of the
cigarette being partially unravelled;
Figs. 5A and 53 are flow diagrams of st=ps in a
preferred prOCeS5 Of making bO~L'blnS Of- r t_?°_ tObaCCO Web Of~
the cicar_tte shown in F_cs. aA anc 43, W~er=_n Fic. SA
SNOWS t he Steps Of COnVn~; ing tObaCCO ~~eCSL~~,C;t in .'.O a S. eat
Of tObaCC'J W2b, and F ? C . » SNOWS t =a S t=~ S Of- C OnVar tinC
the tobacco web sheet into :.~,obbins of tobac~~ web;
F ig. 6A is a cross-secti oval side v=aw of a cigar ette
constructed ir_ accordance with a substantially hollow
embodiment of the present invention;
Fig. 6B is a graphical representa_-on c. aerosol
production versus time during each puff as gene=ated by a
cigarette constructed in accordance with t~~ substantially
hollow embodiment of the present invention c. rFig. 6A;
Fig . 6C ~ is a layout of a smoke measur ing devi ce that
was used to establish data that is represen~ed is =igs. 6B,
7B and 8;
Flg. 7A 1S a CrOSS-SeCtlOnal Si--°, View Of c Cigarette
constructed in accordance with a ful'_.y-filled embodiment o~
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the present invention;
FiS- 73 is a graphical representation of aerosol
production versus time during each puff as generated by a
cigarette constructed in accordance with the fully-filled
embodiment of Fig. 7A;
Fig. 8 is a graphical compar~sor_ of aerosol volume at
each se~~ential puff as delivered by each c'_carett= of those
described in reference to Figs. aA, 6~? and 7~;
Fig. 9 is a graphical presentation of the re?atior_sizip
between the deli very of total partic~~l ate r.,atter (TDI~~ and
the amoc:~t Oi heater Over ~ ap CVe~ th° fll~ c."_ pOr ti On Of the
Dar ti all Y fil l a3 Cl.garette COnStruCte n '
1__ aCCOr OanCe w=th
c ra=a,~~~. ~F i C d~~ O. t~e r v
th- p-_-__-ed embodiment p_esent iwen~icr_;
Fi c. 10 is a crass-secti opal s'_c~ vi ew '- r.a_
oy a cica_..._te
cons~ruct~d in accords. ce wi t'_~_ a secor.c pre===red embodiment
of the p=a ent invention;
Fig. 11 is a cross-sectional sic. view of a cigarette
construct'3 i n accordance wi th a third pre_'rrea e;~odiment
of the present invention;
FIG. 12 is a site, cross-sectioal v_ew of a heater
fixture e_~,Zbodyir_g a further aspect of the p=esent invention;
FIG. 13 is a site view of a heater assembly embodying
a further aspect of the present invention;
FIG. 14 is a site, crass-secticr_al view of a heater
fixture e.;~odying a further aspect of the p-esent invention
employing an electrical insulator coat_ag;
FIG. 15 is a side, cross-sectional v_ew of a heater
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fixture embodying an aspect of the present invention
employing an electrical insulator coating forming a hub;
rFIG. lo' is a side, cross-sectional view of a heater
fixture embodying an aspect of the present invention having
serpentine shaped heater blade legs;
FIG. 17A is =rout, cross-sectional view of a heater
blade having a pl zna= undersi de f=_cing a_n ir_serted
cigarette;
FIG. 173 is a front, cross-secti oral vi ew of a heater
blade havi~g an angled underside .acing an inserted
ciga-ette;
FT_G. ~7~ 1S n front, C=OSS-SeCt_v~~:cl View Of a heater
blade having a CL=r'ved underSid°_ -acing an i
nserte..
cigarette;
FIG. 13 is a top v? ew of a symmetrical a=rancement of
heater blades in a flat state prier to rolling;
FIG. 19 is a ton view of a non-symmetrical arrangement
of heater blades in a flat state prior to rolling;
FIG. 20 is a radial cress-sect'_onal view o. the
electriczl smoking system embodying the preseTt invention,
showing an alternative heater embodiment;
FIG. 2. is a lor_ci tudinal cross-sectional vi ew of the
flavor cart='_dge receiving cavity of the electrical smoking
system of FIG. 20, taken from line A--A of FIG. 20;
FIG. 22 is a radial cross-sect_onal view showinc
another alternative heater embodiment; a=d
FIG. 23 is a longitudinal c_oss-sectional view of the
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flavor cartridge receiving cavity of the electrical smoking
system of FIG. 22, tak=n from line B--B of FIG. 22.
° ~~°d T~eS~r? Dt? Or! O' t~'1° pr°rn...r°"
p~nrii ma.,r c
ic.Sferrlng t0 Figs. ]. and 2, a preferred embodiment Of
the present invention provides a smoking system 21 which
includes a partially-filled, filler cigarette 23 and a
reusab?e lighter= 25. The cigarette 23 is aCa.-.~ted to be
inserted into and r=moved from a receptacle 27 at a _ront
end pcrtion 29 of t=a lighter 25. Once the ci=areLL_ 23 is
lnSerr.Sd, the smok'_nC System 21 i S used In .TJ.:Ch t ,° same
fashi cn aS a mor= tradi ti On al Ci gazette, but W_thOtlt
light_ng or smolderi ng the cigar=cLe 23 . Th= cigarette 23
is d_scarded after or_e or more puf= cycles. Pref=rably,
each cigarette 23 provides a total of eight puffs (puff
cycles) or more per smoke; however it is a matter design
exiled' _nt to adjust to a 1 esser or greater tcLzi nu;nber of
available cuffs.
The li gi-~ter 25 i ncl udes a housi ng 31 hav'_-g f=ont and
rear sousing portions 33 and 35. Or_e or more batter_es 35a
are removably ~locate~. within the rear housing portior_ 35 and
supply energy to a plurality of electrically res'_stive,
heati-g elements 37 which errs arranged wit='_n the front
housi__~_g portion 33 adjacent tile receptacle 27. A control
circuit al in the front housing portion 33 establishes
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l
electrica_L communi~:;~;.t i on between t:tne batteries 35a and the
heater elements 37. Px:wf:erabl.y~, the rear portion 3~~ is
adapted to be readi.:Ly opened arid closed, such as with screws
or snap-fit cc~mponf:~rat;=~, t.o facilit=ate replacement of: the
batteries . If des i_x:w~d, an el e~tri_c~al soc~lcet or contacts may
be provided fc-_~r re~:l:~arging the batteries with house current
or the like.
Preferably, tne~ f rout housing potion 33 is removably
joined to the rear l:u_~usi.ng portion _?5, such as with a
dovetail joint or a:r pocket f:i.t. The housing 31 is
preferabl~r made frcorn a hard, heat:-resistant material..
Preferred material:> i.ncl.ude metallic or, more preferably,
polymeric material;:>.. Preferably, the housing 31 has overall
dimension: of abou~: 10.7 cm by 3.8 cm by _L.5 cm. so that it
may fit comfortabl.y,T irr t: he hand of a smoker.
The batteries 3va are sized to provide sufficient power
for the heaters 37 t~:~~ function as intended and preferably
comprise a replacea:r);>>1e and :rechargeable type. Alternative
sources oi= power an:-e suitable, such as capacitors. In the
preferred embodimerut~, the power source comprises four
nickel-cadmium batwf~~:r_-vr cells connected in series with a
total, non-loaded v:rc~:lt~age of approx:imatel;T 4.8 to 5.6 volts.
The characteri.stic,:> required of the power source are,
however, ;~elec:ted i.r:, view of the characteristics of other
components in the :~rnoking system 21., part=icularly the
character:istic~s of t::~ie heating elements =}.'l. U.S. Patent No.
5, 144, 962
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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 capacitor which is recharged by a battery.
Referring now to Fig 3, the front housing portion 33
of the lighter 25 supports a substantially cylindrical
heater f'_x~ure 39 which slidingly receives the cigarette 23.
The heat=r fixture 39 houses the heater elements 37 and 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 at
approx_mataly tile same location along each cigarette. Where
each hen=er element 37 bears against (or is in thermal
contact with) a fully inser=ed cigarette 23 is re°erred to
herei= as the heater footprint.
To assure consistent placement of the heating elements
37 relative to each cigarette 23 from cigarette to
cigarett=, the heater fixture 39 is provided with a stop 182
against which the cigarette is urged during its placement
into the lighter 25. Other expedients for registering the
cigarett_ 23 relative to the lighter 25 could be used
instead.
The front housing portion 33 of the lighter 25 also
includes an electrical control circuitry ai which delivers a
predete_:..ined amount of energy from the power source 35a to
the heat=ng elements 37. In the preferred embodiment, the
heater fixture 39 includes eight circumferentially
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spaced-apart heatimc~ element=s 37 which arr= concentrically
aligned with t=he r,:~ceptacle a?7 arid c.f serpentine form.
Details of. they hear:E~r :~ 37 are illustrated and described in
commonly assigned ~J.;_;. ~>atents Nos . 5,'05, 214 and 5, 388, 594.
Additiona7_ heater =: ix.ture s 3'7 that. are operable as ~~art of
the lighter 25 inc:_uc~e those disclosed in commonly assigned,
U.S. patents Nos. ~=,665,262 and 5,498,855; and in th.e later
portion of: this de;sc:~~-ipt.ion given with re~~pect to Figures 13
to 23. Preferably. the heater; 37 are inc.~ividually
energized by the pcnwer source 35G. under the control of the
circuitry 41 to he~:~t the cigarette 23 preferably eight times
at spaced location::a about the periphery o:f= the cigarette 23.
The heating render~~ eight puffs from the cigarette 23, as is
commonly achieved ~:~i.th the smoking of a more traditional
cigarette. It. may ko=a preferred to fire more than on.e heater
simultaneously for one or more of the puffs.
Another prefe:-red heater arrangement is set forth in
EP 0 703 x'34.
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27.
Referrincr bac:;;. t.o F i-g . ;~ , preferably, the circuitry 41
is activated by a tm:~ftv--actuat:ec~ ~>ensor 4 5 that is sensitive
to either changes zu prey)sure or changes in rate of air flow
which occur u~>on i:n:..i.- i.at;ion of a draw on r_he cigarette 23 by
a smoker. The puf t=--:~c~tuatPd sen~aor 45 is preferably located
within the front hc:~u~>ing portion 33 of the lighter 25 and is
communicat=ed with :~ :--)pace i:iside trm~ heater .fixture 39
adjacent t:he c.~igar~_~t:.t:.r~ 23 through a passageway extending
through a spacuer ate t: he base of the heaterr fixture ='~9 and,
if desired, a puff ;sensor tube (not, shown). A puff-actuated
sensor 45 suit:.able for use in the smoking system 21 is
described in c:ommoi~.1-y as~~ign.ed U.S. Paten-~ No. 5,06C),671.
The puff :sensor. 45 preferably comprises a Model 163F~CO1D35
silicon sensor, mai:mf:actured by t=he Micro Switch division of
Honeywell, Inc., Freeport;, Illinois. Flow sensing devices,
such as those usin::~ lnot--wire anemometry principles, have
also been succ;essf!.zl.ly demonstrat=ed to be useful for
activating an appr.:~~>.riate or..c~ of the heat:~~r element~~ 37 upon
detection of a chamc~f~ in air flow. Once activated by the
sensor 45, the conl~x~c>i. circuitry 41 directs electric: current
to an app:ropr~.ate ~:~ne of the heat~er_ eleme:rlts 37.
An indicator ~~7_ is provided ate a location alone the
exterior ~~f t:he li~~ht:er a?5, prefer<~bly on the front housing
portion 33, to ind:i.cate the number of: puffs remaining in a
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smoke of a cigarette 23. The indicator 51 preferably
includes a seven-segment liquid crystal display. In the
preferred embodiment, the indicator 51 displays the licit
"8" when a cigarette let=ctor 53 detects the presence of a
cigarette in the heater fixture 39. The detector 53
preferably comprises a light sensor at the base of the
heater fix=ure 3° that detects when a beam of light is
reflected off an inserted cigarette 23. Thereupon the
cigarette detector 53 provides a signal to the circuitry ~l
which, in turn, respor_sively provides a signal to the
indictor 51. The display of the digit "8" on the indica~~r
51 r=flects that the eight puffs provided on each cigar~~==_
23 a=a ava_? abl e, i . a . , acne eL the heater elements 37 ra-Te
been activated to heat the cicar~=to 23. After tie
Clgar°_tte 23 1S sully S:atolCeC, the lnalCatOr dlSplayS t~e
digit "0" . Whe- the ci gar=tte 23- =s--removed- from -the
lighter 25, the cigarette detector 53 no longer detects a
presence of a cicarette 23 and the indicator 51 is turned
off. The ciga=~tte detector 53 is modulated so that it
does not consta=tly emit a beam of light, which woLld
otherwise create an ur~ecessary ~~-ain on the power source
35a. A _,-eferred cigarette detector 53 suitable for use
with the smoking system 21 is a Type OPR5005 Light Senscr,
mane°actu=ed by OPTEX Technology, Ir_c., 1215 West Crosby
Road, Carrollton, Texas 75006, USA.
In the alternative to displayinc the remainder of the
puff count, the detector display may instead be arranged to
s
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23
indicate whether- t:ue sysi=er~u is acr. 'tt~re or inactive ( "on" or
"off") .
As one of sev~era-1 posse-ble alternatives to using the
above-noted cigare~~t;f-~ detector 53, a mechanical switch (not
shown) may be prov.i.ded to dF~rect the presence or absence of
a cigarette 23 and a reset b~.ztton (not shown) may be
provided for resetting the circuitry 41 when a new cigarette
is inserts=d into the -righter 25, e.g_, to cause the
indicator 51 to di~:~play t:he iic~it= "~", et~s. Power :sources,
circuitry, puff-actv..~ated sensors, and indicators useful with
the smoking system 2L of the present invention are described
in commonly assign.=rd, U.S. Patents Nos. 5,060,671 and
5,505,214.
Referring now t.o Figs. 4A and 4b, the cigarette 23 as
constructed in accordance with the preferred embodiment of
the present invent:LC:~iu comprises a tobacco rod 60 and a
filter tipping 62, which are joined toget:lzer with tipping
paper 64.
The partially-filled, filler- cigarette 23 preferably
has an essentially constant diameter along its length and,
which like more tr<:~c~'.itional cigarettes, is preferably
between approximatt~ly 7.5 mm and 8.5 mm in diameter so that
the smoking system 21 provides a smoker a familiar "mouth
feel" . In the preJ:e:rred embodiment., the cigarette 23 is 62
mm in overall lengt:ln., thereby facilitating the use of
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conventional packaging machines in the packaging of the
cigarettes 23. The combined length of tile mouthpiece filter
l0a and the free-flow filter 102 is preferably 30 mm. The
tipping paper preferably extends approxi:aately 6 mm over the
tobacco rod 60. The total length of the tobacco rod 62 is
preferably 32 mm. Other proportions, lengths and diameters
may be selected instead of those recited above for the
preferred embodiment.
The tobacco rod 60 of th=_ cigarette 23 preferably
includes a tobacco web 66 whit: has been folded ir_to a
tubular (cylindrical) form.
overwrap 71 intimately _zwraps the tobacc:, web 66
and is =eld together along a loncitudinal seam as is common
i n COP_svr11CL1on Of more trad_.-.iOncal Clgar°t i-eS . T~'1°
ove="v=ao 71 retains the tobacco web 66 in a wracned
condition. about a free-flow filter 74 and a tobacco plug 80.
Preferably, the cigar=tte overwrap paper 71 is wrapped
intimately about the tobacco web 66 so as to render external
appEcrc~Ce and feel Cf a mcr? traGit10na1 C7.garette. It haS
been found that a be~~er tasting smoke a achieved when the
overwrap pacer 71 is a standar~ type of cigarette paper,
preferably a flax paper of approximately 20 to 50 CORrSTA
(defined as ~ the amount of air, measured i n c~.ibic
centime=ers, that passes grouch one s~zare centimeter of
material, e.g. , a paper sh eet, in one minute at a pressure
drop o. 1. 0 kil opascal) and more preferably of about 30 to
45 COR-:STA, a basis weight of ap proximately 23 to 35 crams
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per mete_~ sw.ared (g/m~) and more preferably about 23 to 30
g/m2, a_nd a fil 1 er loading (preferably cal cium 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 =anging from 0 to approximately 2.5o by weight of
the overwrap paper 71 and more preTerably less than '!'-..
The tobacco web 66 itself pr=ferably comprises a base
web 68 and a layer of tobacco flavor «<ater_al
70 located
along t~. l.ns=de Surface Of the base We0 68. .Zat th°_ t?ppeG
end 72 of the tobacco rod 60, the tobacco web 66 together
with the over-~r=av 71 are wracved about the tubular ==ee-flow
filter p 1 ug 7a . The free-fl ow f__=er 7~ DroV'_de5 st.-.:ctura'_
definition and su~~ort at the ti~aed a~d 72 of the tobacco
rod 60 and permits aerosol to be w'_thdra~an from the interior
of the tobacco rod 60 with a minimum pressu=a drcp. The
free-flow fil tar 7a also acts as a flow cor_s~=ictior_ at the
tipped end 72 of the tobacco rod 60, which is bel_eved to
help promote the formation of aerosol during a craw on the
cigaret~e 23. The free-flow filter is ~=eferebly at least 7
millimeters long to facilitate mach_ne handling and is
preferabl y annular, although other shap es ar_d types of low
efficiency filters are suitable, _-cluding cy?indrical
filter plugs.
At the free end 78 of the tobacco rod 60, the tobacco
web 66 together with the overw=ap 7? are wrapped about _
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cylindrical tobacco slug 80. Preferably, the tobacco plug
80 is constructed separately from the tobacco web 66 and
comprises a relatively short colimn of cut filler tobacco
that has been wrapped within and r=rained by a plug wrap 8a.
Preferably the tobacco plug 80 is constructed on a
conventional cigarette rod making machine wherein cut filler
(preferably bl ended) is ai r formed into a conti nuous rod of
tobacco on a traveling bel_ and e:wrapped with a continuous
ribbon of plug wrap 84 which is then glued along its
longitudinal seam and heat sealed. However, in accordance
with the preferred embodiment of t=~e present inientior_, the
slug wrap 84 is preferably constructed =rcm a ce=lulos'_c web
of little or no filler, s'zing c. bur n adc~~=ves
(each at
1 evel s bel ow 0 . 5% weight p e=cent) and ~refer ~lv 1 i__le or
r_o sizing. Pr=ferably, to tobacco plug wrap 8"-_ has a low
basis weight of below 15 grams D=r meter scua=_d ar_d morn
preferably about 13 grams per meter s=oared. The tobacco
plug wrap 8a preferably has a hig~. pe=-meability in the range
of about 20,000 to 35,000 CORESTA and more pre.°_==b1y in the
range of about 25, 000 to 35, 000 COREST~, anc i s cor_st=-v.cted
preferably from soft wood fiber pulp, abaca-tyke cellulose
or other long fibered pulp. Such papers are available from
Papierfabrik Schoeller ar_d Hoescht GI~3H, Post=ach 1155, D-
76584, Gerr_sback, GERMANY; another paper suitable for use as
the plug wrap 84 is the paper TW 2000 from Be!~Iauduit of
Euimperle FRANCE, with the addition of ca=boxy-methyl
cellulose at a 2.5 weight percent level.
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The tobacco rod making machine is operated so as to
provide a tobacco rod density o. approximately .17 to .30
' grams per cubic centimeter (g/cc), but more preferably in a
range of at least .20 to .30 g/cc and most preferably
between about .2x to .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, i t i s to be ~-:derstood that
the lower rod densiti es wil 1 al low the tobacco column 82 to
contribute a greater proportion cf aerosol ant flavor to the
smoke. Accordingly, a balance must be struck between
aerosol celivery (which favors a low rod cansity is the
tobacco column 82) and the avo_dance of lecse-ends (whit=
favors the elevated rances of roc da~s'_ties).
The tobacco colum:-i 8x pre=erably compr_ses cut filler
of a ble__d of tobaccos t cal of t___ indL._ _
yfli ~~ ~=-ry, incl udi ng
blends comprising brig=t, bur__y and ori=ntal tebacccs
together with, optionally, recor_stituted tobaccos and other
blend components, including traditional cigarette flavors.
However, in the pr_ferr=d embod-ment, the cut filler of the
tobacco column 84 comprises a blend of bright, burly and
oriental tobaccos at the ratio o. approximate_y x5:30:25 for
the U.S. market, without inclusion of reconstituted tobaccos
or any aLter~ cut flavorings. Optionally, an expanded
tobacco component might be inch~ded in the bl end to adj us t
rod density, and flavors may be added.
The continuous tobacco rod formed as cescribed above
is sliced in accordance with a predeter-,nined plug length for
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the tobacco plug 80. This length is preferably at least 7
mm in order to facilitat= machine handling. However, the
length may vary f=om about 7 mm to 25 mm or more depending ,
on preferences in cigarette design which will become
apparent ir_ the description which follows, with particular -
refe=ence to Figs. aA a_nd ab.
As a general mate=r, the length 86 of the tobacco plug
80 is preferably set relative to the total le__~_gth 88 of the
tobacco rod 60 sec:l that a void 90 is defi~ed along the
r-,~ r or o ~ =rec_rl f i leer 7a and the
toba.._o od 60 i~__we_n t__e __ ~_ow
tobacco plug 80. The void 90 corresponds to an unfilled
pOrt_On of tile tObaccO =Od 60 and is i n i t::~1°,~,~.i at.°_ f
1 uid
COmi:i_ =iCati Cn wl.t~ t he t_pDi:lc 62 t ..ouch ~~~ f=e° fl OW
filt°_. 7a c. the tobacco rod 60.
Re=er=_ng pa==ic~=l ar_y to Fig.~A, the l e-cth 86 of t~~e
tobacco pleg 80 a~d its relative posit-on alor_c the tobacco
rod 50 is also selected in relation to fe_~ures of the
heater elements 37. Y~ihen a cigarette is properly positioned
agai-St the Stop 1~2 Of t=° heat.. fiXtu=°_ 3~, a pO~tlOn 92
of each hearer element 37 will cor_tact the tobacco rod 60
alone a recior_ cf the tobacco rod 60. T_'_=s recion of
contact is referred to as a heats= footprint 9"-_. The heat..
footprint 9= ~~(as shown with a double arrow in Fig. ~A) is
not part of the cigarette structure itself, bur instead is a
repr_sentation of that region of the tobacco rod 60 where
the heater element 37 would be expected to r=ach operative
heat_ng temperate=as during smoking of the cigarette 23.
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PCT/US96/05417
Because the heat=ng elements 37 are a fixed distance 96 from
the stop 182 of the heater fixture 39, the heater foot print
y 9a consistently locates along the tobacco rod 60 at the same
predetermined distance 96 from the free end 78 or the
tobacco rod 60 for every cigarettz 23 that is fully ir_serted
into the lighter 25.
Prefe=ably, the length of the tobacco plug 80, the
length of tile he=tar fcotprint 9~ and the distance between
the heater footpr_nt 9~ ar_d the stop 182 are sel acted such
o n o,.- f ,-; -, o a
tha= the h__t__ ootp____t exte__ds beyond the tobacco plug
80 and super-poses a por~ion of the void 90 by a distance 98.
The distance 98 :,y whit: the heat=r footprint 9~ supe=-pcses
th=_ void 90 (the ~.~T=il_ed portion oz the tobacco rod 60) is
n
also rere==ad to as the heater-void overlap" 98. '='he
dis=ante by whit the -emaincer of the heater foottri~,t ga
superposes the tobacco plug 80 is referred to as the
ha=ter-filler overlap" 99.
The tipping 62 pre=erably comprises a free-flow filer
102 located adjacent the tobacco rod 60 and a mouth~i=ce
filter plug l0a at tile eistal end of the tipping 62 from the
tcbacco red 60. Prn=erably the free-flow filter 102 is
tubular a:~d trans:,iits air with very little pressure drop.
Other lOW °fflCi$nCy filters Of Standard COnfiguratiOn COUld
be used instead, however. The inside diameter for the =nee
flow filt_r 96 is preferably at or between 2 to 6
millimeters and is pre=arably gr=ater than that of the free
flow filter 7a of the tobacco rod 60.
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The mouthpiece filter plug 104 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 10a comprise a low
efficiency filter of preferably about 15 to 25 percent _
efficiency.
The free-flow filter 102 and the mouthpiece filter
plug 104 are preferably joined together as a combined plug
110 with a plug wrap 112. The plug wrap 112 is preferably a
porous, low weight plug wrap as a cor_ventionally available
to those in the art of cigarette making. The combined plot
110 is attached to the tobacco rod 60 by the tipping paper
6a of specificatior_s that are standar3 and conventionally
used t h=oughout the cigarette i r.dust_-r. The tipping nape=
6a may be either cork, white or ar_y other color as
decorative preferences might sugc=st.
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 110 of the tipping 62.
Accordingly, the tobacco rod 60 is 32 mm long. Prefe=ably,
the free-flow filt== 74 of the tobacco rod 6o is at least 7
mm long and the void 91 between the free-flow filter 7~ and
the tobacco plug 80 is preferably at least 7 mm long. In
the preferred esbodiment, the heat.r foot print 9a is
approximately 12 mm long and locat_d such that it provides a
3 mm heater-void overlap 98, leaving 9 mm of the heater foot
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print 9a superposing the tobacco plug 80.
It is to be unnerstood that the length of the void 91
and the length of the tobacco plug 80 may be adjusted to
facilitate manuf actu=ing and more importantly, to adjust the
_ smoking characteristics of the cigarette 23, including
adjustments in its tast_, draw and delivery. Tie length of
the void 91 a_nd the amount of heater-filler overlap (and
heater-void overlap) may also be mar_ipulated to adjust the
immediacy of respor_se, 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 t'_he heat_rs.
aTarrc
In the pr__ __ _ _d embociment , t he void 91 ( the f il l er -
free portion of the tobacco rod 60) extends apc=ox_mate?y 7
mm to assur_ adecuate Ilea=ance between the heater foot
print 9a and tile .ree-_low filter 7Q. In this way, margin
is p=oyined such that the heater foot print 9a does not heat
tile free-flow filter 7a du=ing smoking. Other lengths are
suitable, for instance, if manufacturing tolerances pe=-mit,
the void 91 might be configured as short as approximately
mm or less, or i n t!~e other extreme, extended well beyond 7
mm so as establish an elor_gate filer-free portion along the
tobacco rod 60. The preferred range of lengths for the
filler-free portion (the void 91) is from approximately amm
to l8mm and more preferably 5 to 12 mm.
The base web 68 physically separates the heating
elements 37 from the tobacco flavor material, t=ansfers heat
generated by the heater elements 37 to
h
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the flavor material 70, and maintains physical cohesion of
the tobacco'rod during handling, insertion into the lighter
25 and removal of the cigarette after smoking.
w
In the description which follows, certain percentage
levels and/or relative weights are set forth for the various
components comprising the tobacco web 66. Unless otherwise
expressed, or otherwise readily apparent to one of ordinary
skill in the art to be to the contrary, recitations of
weight percentage are on a dry weight basis, that is, the
recited percentage levels and/or relative weights are
adjusted for (do not include? moisture cort~nt.
The process for menu=ecru=~ng the tobacco web 66 is
pref=rably without the add_c-on of carbon-fiber as will be
described in paragraphs which follow. At the conclus'_on of
the t~refe=r°-d manufacturi:.g process, the base web 68 itsel f
has a preferred total basis weight of approxima~_ly 35 to a~
g/m2, more preferably approx_mately a0 g/m2. At a0 g/m~, the
base web 68 preferably comprises approximGtely 28 g/mz
tobacco fiber and approximately 12 g/mz cellulosic fiber
such as from wood pulp or flax. The csllulos'_c fiber serves
as a cel 1 ulosic str~ngthe_~_' ng agent i n tine composition of
the base web 68. It is pr°_f=rr°-d to min=mize the amount of
cellulosic fiber in the bass web for subjective reasons (to
avoid establishing a papery note to the taste of the
cigarette?. C-ene=ally, the ratio of tobacco fiber to
cellulosic fiber in the base web 68 on a dry weight basis
should range from approximately 2:1 to a:l. The preferred
SUBSTITUTE SHEET (RULE 26)
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33
PCT/US96/05417
cellulosic material is an unbleached, kraft softwood
cellulose, although most wcod and ._-'lax pulps are workable.
An alternative strengthening agent for the base web 68
is cellulosic fiber from produced tobacco stem.
' Although it is not arefez-=-ed, alginate may be canted
along one side of the base web 68 at a level of
approximately 1 g/mz. __ alginate is. applied, it is
pre_erred to be applied on a sine of base web 68 opposite of
the side receiving the tobacco favor material 70.
The tobacco malarial 70 is preferably applied to the
base web 68 at dry weight levels of at least twice ar_d more
preferably about thr_e to .our times tha~ of the base web
re f rro.:
68. I. the p e___.. embcc'_ment, the tobacco ma~~rial .as a
basis weight of app=oxima=ply 130 g/m~ so that prer~rably
the c=and total weight of =ze tobacco web 56 is
approximately 170 g/m=. Or_ a d=y weight basis, the tobacco
material 70 comprises a porticn of ground tobacco and
extracted solids at a ratio in the range of approxir"ately
3 . S to 1 ( 3 . 5 :1 ) to f ive to one ( 5 : 1 ) by we ~ gh t , al though
this ratio may be varied in a r~~ge from approximately 3:1
to 9 :1 . In the pry===red =.,tbodiment, ~ t .e ratio is
approximately a.l.
Glycerine is adned to the tobacco material 70 as a
humectant and as an aerosol precursor at l wels of about 10-
lae, most preferably approximately Lea by dry weight cf the
tobacco material 70, but this add-on level may be varied
anywhere from approximat=ly S% to as high as 20: or more by
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
WO 96/32854 PCT/US96I05417
34
dry weight of the tobacco material 70. when glycerine is
reduced to only about 5 to 7% dry weight of the composition,
the tobacco web 66 may be somewhat stiff=r and more
resistive to collapse when rolled into a tubular form.
Pectin is also added to the tobacco material 70 at dry '
weight percentile levels ranging from about .S to 2'-..,
preferably about l.a%. Pectin is added as a coating agent.
In its absence, the tobacco material 70 may t=nd to drain
into (penetrate) the base web 68 excessively during the
coating operation, rendering a grainy su=face texture on the
coated side of the tobacco web 66. Too much pectin hampers
Denetration, and weakens the bond between the tobacco
material 70 gad the base web 63 . At aDDrOXIa.T:cv.e1 y 1 a , the
pect=n promotes adea~aate penetration and bondi._-_g between the
layers so that the base web 68 may wi t~!stand th a rigors of
automated cigarette making.
Most preferably, the tobacco mate=ial 70 on the base
web 68 comprises approximately 16-20% by dry weight
extracted tobacco solids, 66-71% by dry w'ight g=ound
tobacco particles, 8-14a slycerine and approximately 1.4%
pectin. For U.S. markets, the ground tobacco which is
incorporated into the tobacco mate=ial 70 preferably
comprises a blend of bright, burley and orieaal tobaccos
wherein almost hal-_' of the blend is bricht tobacco,
approximately 1/3 is burley and the remainder is oriental.
The composition and relative amounts of the ble=d components
SUBSTITUTE SHEET (RULE 26)
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PCT/US96/05417
may be advantageously adjusted to meet consumer-preferences
in the U.~. or other markets.
Ref _r r i ng to Figs . 5A and 5B , the pre=er red method of
manufactL=ing a stock of tobacco web 66 in a forn. suitable
for the automated manufactures of the cigarettes 23 comprises
a first series of steps 120 (shown in Fig. 5A) for the
eonversic~ of tobacco f eedstock, preferably tobacco strip,
into a tees inuous, sheet of the tobacco web 66s and a second
series o. steps 122 (shown in Fig. SB) o= converting the
continuoLs sheet of tobacco web 66s into or_e or r,~ore wound
bobbins 66b of tobacco web that are in condition =or use in
the autOCi.ated manufacture Of the Clgar°tt~S 23 .
R°_==rring specifically to Fi SA :._ _
g- , t__. process 7.20 oL
converti=g tobacco f_edstock into a cont'_nuous sheet of
tobacco web sreet 66s begins w_=h subject;Tc tobacco
feedstock to an extraction stew 12a (preferably, w'_tii water)
to separates tobacco fiber from tobacco solubles of the
original feedstcck. The tobacco feeds~ock preferably
comprises tobacco strip, but other =orms o. tobacco and/or
tobacco _aminas are suitable for use it this process.
Preferably the tobacco s~rip comprises a blend of aright and
burley tobaccos, and may optionally include o=iental or
other va=ieties.
The tobacco fiber collected from the extraction
process 12a is itself subjected to a paper-making type
process 126 to form a continuous sheer 68s c. the base web.
In the process 125, the tcbacco fiber from the
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
WU 96/32854 PCT/US96/05417
36
extracticn step 12a 1S dispersed in water with the addition
of a predetermined amount of cellul osic fiber which sewes
as a strengthening agent in the composition of the base web
58. Preferably, the cellulosic fiber comprises pulped
cellulose from wood, flax and/or tobacco stem. Once
combined, the mixed dispersion of tobacco fiber and
cel l ulosic fiber is refined so as to form a web sl urry 128
suitable for casting in the casting step 130, wherein the
web slur=~y 128 is directed to a casting box arrangement of a
web forning machine and cast upon a fourdrinier wire o_~ on
an endless steel belt, preferably the former.
a i v=i o i n ' -.rrc
It is mor_ exped_ent to r___r__ the d_sperse~ m_x____
of tobacco fiber ar_d the strengLhe~ing ager~t af==r m'_x=ng
the two components together. They may ir_scead be re=_ned
separately and then combined.
Aft=r tine casting .step 130, the resultant web 132 is
then diracted through one or more driers at a d=-ying step
13a, which step preferably comprises passing the web over a
Yankee crier and one or more can dr_ers, although a hcsL of
a?~ernat_ve arrangements ar_d devices are knowr_ in the
pertine_~_t art and available for executing the d='ying step
13a. At the conclusion of the web drying step 13~, a
mor_itoring step 136 is executed to measure the moisture
content and weight of the dried web. The output 138
regarding measurement of moisture content is used to acjust
_z_ _ _~ - ~:.~. ,-.,a
t. a Clrylng Operat10I1 ! 3u t0 aCWl2v~ atlcl Ii1a1i1tc~iW._:c ucsircu
final moisture level in the sheet of base web 68s for
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
WO 96/32854 PCT/US96/054I7
37
purposes of the subsequent coating operation 1Q4. The sheet
of base web 68s is preferably at or about 15: moisture by
weight at the coating operation lag.
Referring back to the monitoring stew 136, the outo_ ut
- 140 rega=ding the weight of the sheet of base web 68s is
used to adjust operation of the casting step 130 so as to
achieve the preferred basis weight in the base web 68 as
previously described. Such adjustments include charges in
the rate at which tile web slurry 128 is introduced into the
casting box of the web forming machi ne is the castir_c step
130.
The web forming step 125 may cptionally _~rther
comprise a coating step 1~2 which coats er_e side of the base
web 68s with alginate at levels previously desc=ibed along
one side of tile base web 68s opposite of the side that
=eceives the tobacco flavor material 70. Eioweve=, it is the
preferred practice to proceed without the applicat_on of
alginate.
At the conclusion of the web forming process 125, the
base, web is in the form of a 'continuous sheet 68s t. at is
conducive to undergoing the coating ope=atior_ i~~. _n the
alternative it may be collected for subse~:ent coating
ooeratior_s off'-line. It is preferable, however to a=oceed
immediately into the coating operation I~a upor_ the
formaticn of the sheet of base web 68s.
P=eferably, the base web 68s enters the coatinc
operation 1a4 at a moisture content of approx=mutely 12 to
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
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38
17s, more preferably la.S to 15.5s moisture.
Referring back to the extraction step 12a, th=_ tobacco
solubles leave the extraction step 12a in the form of a ~
dilute solution comprising approximately S to 10 percent
dissolved tobacco constituents (solubles), more pre=erably 7 '
to 8 percent dissolved tobacco constituents. Preferably,
the dilute solution is not subjected to any evaporative
treatment, so as to minimize the application of he=t to the
solution. The application of heat can have an impact on the
flavor co__~_tributed by the tobacco solubles when smoked as
part of t~. cigarette 23.
These solubl es (also kr~own as "extracted 1 i ~cr" ) from
the extraction step 12a are mixed at a mixi=~c step lay with
additional, finely ground tobacco, glyce=ire ar_c pectin,
together w'_th ware=, all in relative ~mou=s that L=timately
render the final proportional contents as p.eviously
described for the dried condition of the tobacco material
70. In connection with the mixing seep ?a6, ware= is added
(or with =el d) in amounts su_ficient to rends= at the
conclusicn of the mixing step ~2a a dispe=lion of
approximGtely' 20 to 3S pe=cent solids cont~~" mor_
preferably approximately 2a to 26 percent solids content.
The grour_c _tobacco particles of the mixtu=a are ~~eferably
in the ran ge of 60 to a00 mesh, wherein the to ~n "mesh"
refers to a 9Sa passage rate of tobacco particles through a
mesh having the Given _number of openings per srn_are inch.
More preferably, the additional ground tobacco par=icles are
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
WO 96/32854 PCT/IJS96/05417
39
in t he range of approximately 100 to 200 mesh- a:_d most
pref=rably approximately 120 mesh.
Tf the mesh size of the ground tobacco particles is
established above 120 mesh, more specifically at or abou~
180 to 220 mesh, the solids content of .the slurried tobacco
mat=r'_al at the conclusion of the mixing step lab may be
eleva=ed, such as to levels of approximately 2B to 31'-...
Upon conclusion of the mixing step 1a6, the resultar._
Slurr=ed tObaCCO mete=1a1 iS ,directed immediately in~0 the
coating ope=ation 1~-_a, al=hough the coating operation may be
elect'_vely perfoy"ed at some subseauent time en an e-_'-_'-line
basis. At the ceacin cperation laa i.r
g , the s_:.-rigid ~obacc~
mate__al should have a so_ids cor_tent of approx_matei_r 22 to
27% by weic:,~, mor=_ prefer_bl y at or about 2a ~0 25: .
~t the.COat_nc Step laa, the Slurried tO~aCCO Wa_°ria:
has a target weig== perce-t of tobacco solub_as of a to 3
percent, mer= pry=_rably 5.5 to 6.5 weig ~ p t
er ce=~ c.
tobacco SOlubleS. ~referab~y, the Slurried tObaCCO LC~ceria-
enters the COatlnC ODera~~on lad zt a temperazure 'n tho
range of an- proxi:-,:ately 70 to 130° F, more pre=erable at o.
about 90° F plus or minus 5° F.
The coming seep 128 is preferably per=ormed wi th a
standard reverse-rill coa_er located after a Yankee dryer
beyor_c the e__~_dless belt or fourdrini er wi re. The coatinc
step may be perfo=:,ied w_th other suitable coating cevices
that are known ar_d availabl a to those of ord_=~ary sk'_11 in
the a=t of web fo~:"inc operatior_s. The tobacco material 70
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CA 02218595 1997-10-17
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may instead be cast or extruded onto the base web 68.
Alternatively, the application step 128 may be executed off-
line separate from the production of the sheet of base web
68s. Du=ing or after the coating step 128, flavors that are
conventional in the cigarette industry are added if desired. '
At the conclusion of the coating operation 144, a
continuous sheet of tobacco web 66s is produced.
Referring now to Fig. 53, the process now proceeds
through the steps 122 of converting the sheet of tobacco web
66s into a wound bobbin 66b of tobacco web which is suitable
for the automated production of cigarettes 23. ?referably,
the cor_version steps 122 are executed on-line with t'_Ze
production of the cor_tinuous sheet of tobacco web 66s.
During tine execution of t'_he cor_versien steps 122, t ~e
operator szould avoid cond_tions which c=eats b=oaks, tears
or other imperfections in the tobacco web sheet 66s so that
a continuous winding of tobacco web is obtained in the
bobbin 56b with few or no slices. Additionally, the sheet
of tobacco web 66s is to be conditioned such that at the
conclusion of the converting steps 122 the tobacco web will
not bind uaon itself and may be rapidly wound and unwounc
from the bobbin 66b without breakage.
The conversion steps 122 initiate with a drying step
146, wherein preferably the sheet of tobacco web 66s is fed
continuously through -a gas-fired, hot-air impir_cement d=yer
such as the type obtainable from Airtech Systems Corp. of
Stroughton, Maine or with a steam heated, hct air dryer.
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
WO 96/32854 PCT/US96/05417
41
Other Briers that are known in the art of web forming may be
employed instead_ The drying step 146 should be executed
with minimal application of heat but in amounts sufficient
to dry the tobacco web 68s from its initial condition
' (approximately 15% moisture content in the base web and
approximately a 75% moisture level in the coating itself) to
about 8.5 to 12% moisture content overall at the conclusion
of the drying step 146. More preferably, the d_~-ied tobacco
web sheet 66d is in the range of approximately 10 to 11%
moisture content. This final moisture content is preferred
for several reasons: to facilitate slitter operations at a
later s;.age in the conversion process 122; to set a moisture
level which approximates where the mate=_al would
e~uilibr~te when stored znd/or sent to a ma=~ufacturing
acility; and to establish a moisture level w'.~_ich avoids
tackiness and binding of the base web material upon itself
in the bobbin 66b.
Subseauent to the drying step 7.26, the dried tobacco
w°b She°t 66d is cooled to an ambient t_mperature,
preferably that of its li'.~_1y place of storage and/or
associated manu~ac~u=ing facility, usually in the range of
65' to 80° F. This cooling step 148 not only facilitates
eauilibration ~ of the tobacco web 66 to operational
environments, but also avoids the risk of heat being
retaine-? within a bobbin 66b which might otherwise initiate
a self-heating process. If left unchecked, self-heating
could lead to extreme temperatures and degradation of the
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
WO 96!32854 PCT/US96/05417
42
subjective character of the tobacco web 66. Preferably, the
cool ing s tep is per formed with a c =il led-water cooled, air
impingement cooler available from Airtech Systems Corn. of
St=oughtc, Maine, although a host of alternate cooling
systems ar a Jc~-~.own to those of ordi na~~y skill in the ar ~ of
web form=ng.
Af=er the web drying and cool i ng steps 140' and 1 48,
the dried and cooled tobacco web sheet 66dc is passed though
a decurl_r apparatus, such as those offered by Thermo
Electron Neb Systems, II1C. Of ALbLrn, Maine Or Some Other
Su-table web deCUrl er deVlCe aS WOL_d be readily k_'106vTi and
avail able to one of ordinary ski 1 1 in the per tlnent ar a Of
web form-g. At the conclusion cf tae decurling step 150,
the tobacco web 66 is substan t_;? 1 y free of then-"ally
incuced warping along its edges a_-_d is i n cons=tion f:,r a
subseauert winding and slitting steps 152 and 154. However,
prior to the execution of those steps, it is preferable to
monitor ~=mperature, moisture level and total weight of t::e
tOi.cCCO W°b She°t 60'6 aS 1.t 1 eaVeS the deCLrl 1ng Ste'~J 1~0
SO
as to provide feedback and cor_trol c= the process to assure
that the tobacco web sheet 66s is -n condition for winding
a ' i v t i v o 'ran taroat Values Oz
an_ slitt_ng and w_11 r_sul _n th_ d_s~___
te.~,:perat::re and moisture, total weiga for the bobbins 66b.
In =articular, in monitoring t~e tobacco web sheet 66,
the reac_ag of its total weight are used to adjust tile
coy=ing cperation 144, such as in tha feed rate of slurred
tObaCCO .T.cterl.al lnt0 the reverse-r0_~ COater Or the gap at
SUBSTITUTE SHEET (RULE 26)
CA 02218595 2003-05-05
43
the nip of the coater. Readings of the moisture level at
the monitoring ste~E=~ 7_5i are used. t:.o cvont:rol drying
operations so as to achieve the t=arget moisture levels in
the sheet as ciescr_:i.bed prev:iouslv. Likewise, the cooling
step 148 is contro:l:led responsively to readings of t:he
temperature o:f_ the ~>lue et~ of tobacco web 65 at the monitoring
step 151.
Thereafter, the tobacco web sheet 66 is wound at a
winding step :1.52, whLi.c.h is performed with web winding
machines readily known and avap._labl_e to ane of ordinary
skill in t:he art of: web processing. Subsequent thereto, the
wound tobacco web ~~heet 68s is slit: into -individual bobbins
66b, wherein t:he c~..zt~-width for each bobbin is respective of
the desired circumference of the cigarette 23.
At the ccmclu:aa_can of the conversion steps 122, the
bobbin 66b is in condition for automated manufacturing
processes of the c i_<~arettes :?3 , such as i.n the combining
operations disclosed with reference to Fig. 6 of commonly
assigned LJ. S. Patent; IVo. 5, 5c)5, 21.4 .
The glycerin in the tobacco rnat.erial ?0 serves as an
aerosol precursor :un.d facilitates formation of a visible
aerosol during smoJcing of the cigarette 2.3. Additionally,
as the glycerin is released in the atmosphere, it condenses
and provides a.n ap~>e<:~rance typically expected of cigarette
CA 02218595 2003-05-05
44
srr~.oke. Other humectant.s, suitab:L~~ for u:~e in the tobacco
industry rnay be us~ec~ _in i.ts place.
Optic>nal=Ly, a.f:'_er_ the casting Step _L23, alginat=e may be
coated along a side of the web E>8 before, during or after
the coating step :l:%,5., The ~:lgin<~te coating provide;
additional strength and f ilrn form<~ti on a:Long one side of the
base web ~8. However,, the i=ease wE>b E~8 has sufficient
strength without a:l.cynate, G.nd i t: is the preferred practice
to construct t:he b:~~~e web 68 withol.zt it .
The present. iiment:LOn may be practiced with other types
of base webs 68 (c:~rrier:~) , including the r_arbon-fiber mats
or the me~allic or ~~c.reen mats described in commonly
assigned ~::~.S. patent:s Nos. ~,505,:?:L4; 5,369,723; anc~
5,388,594; and our_ tx~ansmiss-ion of European Patent
Application EH?-A-0 , E>:Lt~, 411 .
With regard tca carbon-fiber mats as disclosed in
EP-A-0, 615, 411, an~:i in commonly assigned (J. S. Patent: No.
5, 388, 594, whose c~:~zut:inuation is U.:~. patent No. 5, E66, 978,
a preferrc=_d composition. of such mats comprises a bare web 68
comprisin~~ tobacco t:iber in the r_arlge of 20-30 g/m2, more
preferably approxirru--rt:ely 24 to 2.8 g/m', most preferably 26
g/m2, carbon fiber irn the range ~~~f 2-9 g/m', more prf~ferably
2 to 4 g/mz, and mc:>st preferably
CA 02218595 2004-03-19
apg=ox=mately 3 g/m~; and pectin in the range of
app=oximately .S to 1.5 g/ctt', and must prp=erably
appraxima.tely 1 g!m= pectin. Preferably, chase constituents
are balanced so as to establish a base web 69 having a. tatal
bass weight of approximately 30 g/ml. It is also preferred
to use carbon fiber. of 1/a inch .stxaz~d 1 sng'h to facilitate
its dispersion during the slurry fo=niag portion of the
process. Ia.itiar=or. of dispersion or .he carbon fiber
feecstoCk is faeil='_ated when praceduras are used such as
those disclosed in U_5. Patsnt'Nos..4,007,063 vnd ~,23~,379.
In the alts=-mate ~mbcd_me:-ct of t::a, Lobacco base web 66
(=.s., the ca=bon, fibs= mat?, the_ to4al Li=,fished cx-y sheet '
wei ght i5 pr AfBr.bl y about 160 g/:n~, or which 30 ~Jm
comprises the base wee 68 and 130 g/m' ccmpr=sea the tQbaccc
material 70_ In contrast, the mo=a pre=9===d emoodimeat oz
the tobaeCO base wEb 66, wrich~ does not include carbaa-
flber, has a deed sheet wei ght aL aagrox~'_:~t~ely 17o g/ms,
o~ which a0 , g/m~ comprises the base web 68 arid 13D' g/m
coGprisea the tc~becco material 70.
Whic~WVer tyre of base web 68 toy carri.erl is used,
the tobacco mace=ial 70 is p=e.fe=ably disposed on the inner
surLace or t:ls base ws~r 6cf and. libera,:es a tobacco flavore3
aerosol (response) waen heated. Such materials may also
iriClude caritinuaus sheets, foams, gAl9, d=ipd slur=ies ox
cried sprGy-deposited slurries of tabaCco materia?.
Referring to ~ fig. 3 and in cor_3u.~n.ctian with t~:e
teachings . from coatmonly assignEc
CA 02218595 2003-05-05
46
U.S. Pateo~t No. 5, ?r3f3,59~E, when a cigarette 23 of the
preferred embodi.meazt i.:~ inserted into receptacle 27, it is
guided into the he.:~t_ing fixture 39 until the free end 78 of
the cigarette 23 ah~r.rt:~:, a stop 18<? f~_xedly arranged at the
base of the heater fixture 39. Once the cigarette is in
place, smoking may commence, whereupon amy puffing ~~ction on
the cigarette by a smoker is detected by she puff sensor 45,
which in cooperati~::~n wi.t;h the control cir~~uit 41, causes
electric current t~:~ be delivered to a preselected one of the
heaters 3'7. Power i.~; de l.ivered via an electrical circuit
which includes lea~~~s 1.83 at one end of each heater 37, a
common ring 184 at: t::Ere opposite E~nc~ of. each heater 37 and a
common lead 186 extending from the common ring 184 )r>ack to
the proximity of t'_ne leads 183. As each heater 37 i.s
activated,. thermal. energy is transferred t=hrough they
overwrap ~1 and the tobacco web 68 i.n sufficient amount to
cause the tobacco :favor material. ;'G o:f the tobacco web 66
to release a tobacco aerosol within the confines of the
tobacco rod 60, wh_i_ch i.s drawn from the cigarette 23
responsively to thE:~ puffing action of the Smoker on the
tipped end of the :~i~~arette 23.
A smoker's dry-~w on a c.igaret.te typically endures
approximately 1 . 5 t::o ~~ . 0 seconds, while F'~~C cigarette
testing procedures a;~sume a a.0 second puff duration..
Where the hearer footprint. 94 overlaps the void 91,
aerosol i~~ release~.a ci:irectly from the lzeat~ed tobacco flavor
material ;'0 into tine void 91 whereupon it is withdrawn into
CA 02218595 1997-10-17
WO 96/32854 PCT/US96/05417
47
and through the tipping 62 w=th very little pressure drop.
On the ot'_zer hand, where the heatar footprint 94 overlaps
A -
the tobacco plug 80 (the heater/f_ller overlap 9S), proximal
portions of the tobacco plug 80 will become heated along
with proximal portions of the tobacco web 66. Accordingly,
the ble~ded tobaccos of the tobacco plug 80 contr_bute their
own fraction of the total =_erosol so as to contr'_bute their
taste a_nd other subjective a=tribe=es. The aercsol released
from the tobacco plug 80 at or about the heater/filler
overlap 99 undergoes some filtration and pressure drop as It
is drawn through the tobacco plus 80 and into to void 91.
Tr= aerosol produced =nom rearing of the t~~acco plug
80 has a charact=_r and _aste t_a= can be alt==_d by the
blend c. tobaccos as well as by adjustments in ow much of
the heat_r footprint 9a c~~=lap5 thn tObaCCO pl_C 80. The
compone =~ of aerosol that is prodLC~d ir_ the vici__~_ity of the
void 91 is released more instantar_eously from t=a cigarette,
because there is less tize_;"al i ==r tia at the void 91 and
because the the_,~al.y v~_crized tobacco substance at the
void 91 is not subject to the pressure d=op of the tobacco
plug 80 and is ir_ste_d more immediately commur_ic=_ted to the
tipping 62 through the free-flow =filter 74. It =owever has
a character different from that r=leased from the tobacco
plug 80, because it is ==leased predominately from the
tobacco flavor mater=al 70 on the base web 68. As will be
explained in greater detail below, it has beer found that
for smoker satisfaction, the aerosol deliver_d from a
h
SUBSTITUTE SHEET (RULE 26)
CA 02218595 1997-10-17
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48
cigarette 23 prefer=ably i=eludes both components of aerosol
to assure imme~iate delivery to the smoker and to include
the flavor notes attr'_.butable to blended ct~t filler
tobaccos. As will also become apparent in the teachings
which follow, the presence of the void 91 (and its immediacy
of initial derive=-y) assures a cor_sistent puff-to-puff
smoking Of the Cigar°_tve 23 and prOLitOteS COnslStenCy between
cigarettes. This relatior_ship bears out in the comparative
puff-to-puff attributes of a partially filled cigarette 23
constructed in accordance with the preferred embodiment
(having a plug of cut filler 80 and a void 91), in
comparison wish c=car~ttes 23' of a first alterr_a== design
(Fig. 6a) having no cut =filler within its rolled tobacco
web, and a second alterna=a design (Fig 7A) having a rolled
n ; ~I, r;,i :~h ;iior I :,
tobacco web e__t_re_ ~~__ed w_~ cut f_____ . n t~_e
depictions of these al_~rnate designs, it is to be
understood that the tobacco web 66' and 66" comarise a base
web 68 and layer of tobaco material 70 as in the pref==red
embodiment. The tobacco rods 60' of these a'_ternate designs
also included on ove~-wra~ 71.
A serpentine type heater element at a 15 Joules enercy
setting was used to ge_~_erate the comparative data as
presented in Figs. 6B and 7B with the cigarettes shown in
Figs. 6A and 7A, r=spectively.
In reference to Fig. 6A, a cigarette adapted for
- smoking in an electrical smoking system of the first
alternate design comprises a tobacco rod 60' and a tipping
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62', each which include components designated with prime
numbers having c:ort~esponcien.ce ws_th cvomponents of the
preferred embodimeznt: :shown in fi_~~. ~A. However, the tobacco
rod 60' of the ciga:rett.e 23' does not enclose any cut filler
within its tobacco web 66' and t:he free end 78' of the
tobacco rod 60~ is pz~ovided with a back flow filter 200'.
The base web 68' o:E t;he tob~.cco web 66' was the type
including carbon fiber as previously described. The
construction of ci~~arette 23' is also detailed in the
commonly <~.ssigned IJ. ~3. Patena No. 'p, 388, ~~94 . For purposes
of the description which follows; reference will be made to
this cigarette 23' as a filler-free cigarette 23'.
Refe-rrinc~ now .r.:o Fig. 6~t~, experiments were conducted
using a smoking mar.-rr:i_ne in cooperation wi~h a smoking system
21. The output of t:he smoking machine was directed during
each puff through :~ smoke measuring device 6y havinc; a
transparent chamber 6v, where a beam of a_ight 6u from a
source 6w passes through the transparent chamber 6v to a
photo detector 6z at the opposite side of the transparent
chamber 6v. ~.'he on.zt:put of the phot:c> sensor 6z is processed
to resolve the intc:7rusi ty of thE: ~_ight beam 6u as it strikes
the sensor_ 6z. An~,r tobacco aeroso7_ that passes through the
chamber 6v will hav,re a light scattering effect upon the beam
of light E>u, such v::rw~zt. any resultant charz<~e .in detected
light intensii=:y at t:he photo detec:t:or 6z rain be inversely
indicative of tota.l_ oarti.culate matter (TPM) in the aerosol.
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In accordance with FTC cigarette testing practices, it is
preferred that the smoking machine draws a standard two-
second puff from the smoking system 21. '
The information graphically presented in Fig. 63 shows
the intensity registered at the smoke measuring device
relative to time as the smoking machine progressed through
each of a successior_ of puffs on a filler-free ci=arette
23'. The data indicates the following trends: that with a
filler-f=ee cigarette 23', the first and second pu=fs are
inconsistent with the remaining three puffs, wick latter
three pLffS are muC~ more COIISi Stent Wi th eaC~l oth°r; and
that _aerOS01 1S delivered Well beLOre lapS2 Of t=a tw0-
SeCOnd t?me perl0d for each puff. The filler Lre°_
C_~areLt°_
23' is less consistent in delivery at the first several
puffs and consistency prevails only in the latter puffs.
The data related to the first puf_ is fairly cor_sist=~t with
the general observation that machine smoking of a
filler-=ree cigarette 23' delivers less aerosol dur_ng the
fi rs t nLf~ unless remedial measures are impl eme =ted such as
perforating the tobacco rod 60' or other measures as taught
in U.S. Patent No. 5,388,59a (PM 1697).
Re=erring now to Fig. 7A, another desigr_ of an
electrically bperative cigarette 23 " comprises a tobacco
rod 60 " and a tipping 62 " having compor_ents and an
arrangement similar to those of the preferred e~r;.~,odiment
shown is Fig. aA, with similar components being -rovided
with double prime designations. However, the cigar==to 23"
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of Fig. 7A includes a back flow _-filter 200" at the free end
78 " ar_d a column of cut filler 220" extending along the
entire length oz the tobacco rod 60" between the back flow
filter 200" and the free-flow filter 7a " of the tobacco rod
60 " . The tobacco column 220 " of the cigarette 23 "
comprises the blend of burley, bright and oriental tobaccos
at a rod density of .275 crams per cubic cent=:aeter. The
base web 68" of the tobacco web 66' ' is the tyre incl udi ng
carbon fiber as previously described. In the discussion
which follows, the cigarette 23' ' wil 1 be refer=ed to as a
fully-filled, filler cigarette 23"_
Referring now to Fig. 7B, t he measureme= .s in 1 fight
lntenSity from tze S-coke measur.~..~?G C°_Vlce 6y Wc5 CCrr°_~
ated
with the time lapse progressicn of each duff .or a
succession of puffs ~umbered one t hrough seven c__ the =ul ly-
filled, filler cigararts 23". The data presented in F_c. 7B
is representative of two recognizable tre__~_ds in the
performance of a c'_garette constructed in accordance with
l y eri ~il l er i g re~--a ~ ~ . j..
tine fu__ -fill__, c_ a_ _~ 23 . t_~~_ the =first
several puf~s provi ce signi ficant aerosol dal iv=.~y, but yet
delivery thereafter declines to such an ext_-~ that the
lateer three puffs provide substantially less delivery than
the first several puffs (unless corrective reasures are
taken) ; and with t he full y-filled, fil 1 er cigarette 23 ' ' ,
aerosol delivery is delayed and the initial duffs (puffs
one, two and three) do not achieve maximum de_ivery until
after a substantial portion of_' a two-second period has
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elapsed.
Durinc the _'_rs~ several puffs, the fully-filled
cigar_tte 23" tends to deliver a greater total volume oz
aerosol tha~ the filer-Eras cigarette 23'. A comparison of
the data presented in Figs. 7B and 6B substantiates this
general observation in that the total areas above the first
several puff-lines in Fig 73 for the fully-filled, filler
cigarette 23 " are greater than the total areas above the
fi rst several puff-lines in~ F-g 6B for the fill er-free
cigarette 23' . T~_= area above =ach puff-1 ins in Figs . 73
and 6~ i 5 i~.~-lCati Ve Of tOtGl de_iver-y duri r_g that puf=.
zowever, it is believed tha= the delay in delivery of
the =;=11y-y_lled, _.l~e"' ClgcretCe 23" lnduCes a smoker t0
undertake a prolonc_d, mere rob~_st draw in r=action to his
or her not ~btain'_=g an immedia~_ flavor respcnse from the
cigarette 23" . Th= more pronou =ced draw in t::rn can cause
the heated portions of the overwrap 71 " and the tobacco web
66" to become mere f'~lly consumed (oxidized) by t~~e
addit_onal a=r draw=_ theret'rirough such that more signi=icant
breakage a=~ perhaps localized collapse of the tobacco
colum_-! 220' ' occ::rs during t. a first several puffs.
Additionally, it is believ_d that once pyrolysis is
initiated in the fL'~~~y-filled Cigarette, 1t tends t0 be more
self-sustai_ing, be==use ef the presence of a greater mass
of ccr"bustable tobacco and/or because oz its mere compacted
state. In any eve.., because air may be drawn more readily
lnt0 the tObaCCO rCC through the breached "burn" sltuseS Of
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the first several puffs, these localized breaches are
believed to short circuit the desired air flow paths of
subsequent puffs. Consequently, delivery declines during
the latter puffs on the fully-filled, filler cigarette 23".~
The data presented in Fig. 78 and the explanation
above is consistent with a general obse=--nation that a fully-
f_lled, filler cigarettes 23' or a traditional cigarette,
when they are smoked with electrical lighters, t_nd to dro_o
off in delivery as puffing thereon progresses.
With its delayed, yet more self-sustaining pyrolysis,
the fully-_=11°Q Clga=ette 23' t°ndS t0 generate a Cr°at
amount C= aerOS01 in the l attar Sv.'-..CeS OL the pu=L, and at
times may continue to prod~~ce an amour_t of aerosol beyond
t'_he per_cd of ti me t~:at the smoke= i s actually drawi ng on
t.°_ Clgar=tte. The late°r Situation Ccn r°SUIt 1n the
prOduCtiOn Of "pOSt-puff" a°rOSOI Whl.Ch may linger Within
the housing 33 of the lighter 25, particularly at or about
the heater fixture 39. Score of such "post-puff" aerosol
will problematically ccnder_se on t=a heater elements 33 or
linger long enough to be drawn into the cigarette 23" durinc
the nex~ puff. Either c~r_seauence is inimical to the
delivery of a pleasing and consistent taste.
Re=erring back to Fig. 6B, tine puff lir_es o~ the
filler-Free cigarette 23' evidence that the delivery or
aerosol '--..aximizes (where the puff 1 fines dip the most) well
before tae two (2) second curatior of a standardized guff
has elapsed, and delivery is minimal at the latter stages of
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the puf=, so that the production of "post puff" aerosol is
not such a problem with the filler-free cigarette 23'.
However as noted previously, the filler-free cigarette 23'
delivers less total volume of aerosol than the fully-filled,
filler cigarette 23", it suffers inconsistency at times in
delivery during the first several puffs and it lacks the
subjective attributes and flexibilities that would other-~rise
be enjoyed if bler_ded (or even unblended) cut filler were
incl ucied.
Fig. 8 is a pr=saatation of data from compara~ive
smoking on smoking machines usi ng a smok= measur ing ce~rice
6y as cescribed above for cigarettes consc~scted in
aCCOrda _~C°_ W3.th tile fi 11 'r-yree cigarette 23' ; the ft~l ly-
f111ed, =111e= Cigarette 23''; and the partlcily f~l!eQi
filler c_garette 23 const=scted in accordance wi_h teaciags
of the p=eferred embodiment (as shown in Fig. ~A) of the
present invention. Carbon-fiber mat was used as the base
web in all these cigarettes. As a discussion of the data of
Fig. 8 w_11 reveal, the partially-filled, filler cigarette
23 of t he present invention provides more cor_sis~=nt
delivery throughout a smoke. It avoids the drop in delivery
t . l r r- ll -filie il a
tha _occ_rs in the atte_ pu_cs of the fu__y __ d, f__1_r
cigarett_ 23 "~ and is more consistent in deliver-y than the
filler-==ee cigarette 23' during the first several puffs.
The partially-filled, filler, cigarette 23 that was
tested to coil ect data used in Fig. 8 was hal f-fillet wi th
cut fill== such that the heater overlay over the void in the
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cigarette design was relatively large, aperox_:nately 6mm.
The heater elements 37 used for generating the data
presented in Fig. 8 was a serpentine type at 15 Joules
ener5y per heating cycle.
Referring to Fig. 8 in particular, the data presented
therein is the amount of aerosol (in milligrams) generated
during the first two seconds of each puff in a progression
of puffs during the smoking of each particular type of
cigarette. In relation to the data presented in Figs. 6B
and 73, an amount of aerosol indicated in Fig. 8 would
analytically correspond to an integration of (the area
defined above) each puf'-1 i ne from 0 to 2 seconds in Figs .
6B and 7B.
o ; - = ~ o=ri ~ i ,-
The pr_sentat_on o. data n Fig. 8 c_____y i__ust-at_s
the drop in delivery that is experienced with a fully-
f filled, filler cigarette 23" as one progresses from the
first puff to subsequent puffs. In contrast, the
filler-free cigarette did not suffer the drop in delivery as
with the fully-filled, filler cigarette 23 ".
The presentation of data in Fig. 8 also clearly
illustrates that the partially-filled, filler cigarette 23
provi _des consistency in delivery comparable to that of the
filler-free cicarette 23' throughout the six puf~s.
Furthermore, it does so with a contribution of cut-filler to
its taste and subjective impact.
Referring to Table Ii, data was collected indicative
of how changes in the amount of heater overlap at the void
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in a cigarette constrscted in accordance with cigarette 23
can affect delivery. The data presented in Table II was
y
produced from machine smoking of par~ially filled cigarettes
having a 32 mm tobacco rod, a 7 mm free-flow filter at the
tinned end of the tobacco rod and a 30 mm long tipping,
wherein tine heater footprint was 12 cm long and centered at
t'_'_~_e midpoint of the tobacco rod of each cigarette.
Table II
4oid Length (mm) c 7 '-0
F~eater overlap alongthe void (mm) 1 4 7
_~ter overlap aior_gtze tobacco pl 11 8 S
~
Average T?M ~.9 5.5 7.0
A~justed Average (lowest ==aging 5.2 5.9 7.3
TPM
c,.,i tted)
Standard Deviation Adjusted Ave=ace .3S .53 .SO
of
Fig. 9 provides a graphica_ presentation of total
~articulate matter ('.'?M) delivere3 versus the amount of
heater-filler overlap (in r.:illime~ers). The data shown
therein was generated using standa=3 testing tech_~iques for
determining FTC tar" levels using Cambridge pads and two-
second guff intervals on standard smoking machines. The
tested cigarettes wen. partially-=filled, filler cigarettes
having a carbon fiber base web and a total length of 58 mm,
except that the data appearing alo=g the ordinate in Fig. 9
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were obtained from a fil 1 er-free cigarette hav'_nc a carbon
fiber base web and the same total length. As the heater-
tobacco overt ap was varied, the heater footprir_t remained a
constant length and remained centered upon the mid-point of
the tobacco rod. Accordingly, any increase in heater-
tobacco overlap created a proportional decrease in heater-
void overlap. The heater was a se~entine type having a
heater footprint of approximately 10 mm. All the data taken
together indicates that a second order relatior_shic exists
in these circumstances between total particulate matter
delivered and the amount of heater-filler overlay. The data
presented in Fig. 9 and the separate set of da~a set forth .
in Table II show that the amount of heater-fi=ler overlap
may be adjusted to obtain a desired (targe=) level of
delivery in a partially-filled, filler cigarette 23.
Adjusting the amount of heater-filler ov~rlaa is the
preferred method of achieving a desired "tar" level in
partially filled, filler cigarettes, for reasons including
the finding that changes in heater-=filler overlap have a
more pronounced and controllable effect on delivery than do
changes in rod density at the tobacco plug 80. Also, this
approach allows one to select rod density in the tobacco
plug 80 for .purposes other than tar level, such as to
control loose ends and/or to create a desired degree of
pressure drop and/or filtration at the free a~c 78 of the
tobacco rod 60, or otherwise facilitate manufacturing. It
r zlsa provides the capacity to alter tar delivery amongst
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related cigarette products without having to r_ecessarily
change either the tobacco web 66 or the tobacco pl;:g 80.
r
It is also advantageous to configur_ the relative
dimensions of the partially-filled, filler cigarette 23 ann
those of the heater fixture 39 of the lighter 21 such that
upon insertion of the cigarette 23 into the lighter 21, each
heater element 37 locates alongside the tobacco rod 60 such
that at least some, if not all of the he=_ter -ootprints
supe~~pose only the filled portion of the tobacco rod 60
(over tine tobacco plug 80) . In such con='_curat'_ons, the
V0ld 9' St'_11 faCilitateS aerOSOI fOrmatiOP_ a~d =°-1pS COC1
the smoke. It is believec that the free-=_ow _ilter 7~
hel ps promote ae-osol formation by i is prese_~.ti_-_g a f 1 ow
constriction to the aerosol constituents as they are be_cg
drawn ==om the wider void 9.. In this rega=~, i= is to be
noted that the fre°_-flow filter 7a Of the tObaC=O rod 60
presents edges 73 and 75 at the transiti or_s between it and
the void 91 on one side and between it a. d the _ree-flow
filter 102 or_ the other, respectively. These edces 73 a:.d
75 are a consea-uence of the free-flow filter 7~ having a
smaller inside radius than either of the other two, adjacent
regions (the void 91 and space enclosed with'_~ the free-flow
filter 102). .It is believed that these edges 73 a=d 75 (and
possibly other, adjacent portions of the _=ee-flow filter
7a) promot= turbulence and other flow conditions favorable
to the for;aatior_ of an aerosol from the gas-phase and
particulate phase constituents released from t=a heated
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tobacco portions of the tobacco rod 60.
Referring now t:.o Fig. 7.0, a ~~:igarette 23a is
constructed lIl acC:o:r~dance wi.ch:~ ancar~her preferred embodiment
of the present invcJrxt:ion ha.z~inc~ components and arrangements
the same asset forr_.h it the discussion of r_igarette 23 in
view of Fig. 4A, but with the addi_t~on of a back-flaw filter
200a located at th~:J free end 78a. of the tobacco rod 60a.
The back flow filtr~r.- 200a p.rever~t:;~ tobacco from the tobacco
plug 80a :from escaping at tre free end 78a. The free flow
filter 200a may as well be colored so as to indicate' that
the cigarette 23a is one for use in an electrical smoking
device in:~tear_~ of c:~ne fox- beinc.~ -~gnited with a match or a
conventional. cigar~~t::t:e l.i.ghter a~~ with more traditional
cigarettes. Altho~.zgh the back flow filter 200a is ~;hown as
a separate component. of the wrapped tobacco plug 80a, one
may for convenience. in the rr,anufact:ure of the cigareate 23a
combine the tobacc<:~ plug 80a with t:he back f:Low filter 200a
with a plug wrap f,nc:~t shown) . Wit-:h the back flow filter
plug, the cigarettE, 23a may be px-ovided with a tobacco plug
80a having a low rod density without risking problems such
as loose ends or tcobacco falL.irug out of the tobacco rod 60a.
As revealE~d in EP-1'~-Ci, 615, 41:1., and :in commonly assigned U. S.
patents Nos. 5,505,.214 and 'x,388,594, the back flow filter
200a is configured to limit or wholly prevent the release of
aerosol from the fu:~ee end 78a of the tobacco rod 60a at the
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conclusion of a puff and to ..reate a pressure drop at the
free end 78a so as to favorably limit the amount of air that
is drawn into the cigarette 23a from 'the free end 78a in
relation to the proportional amount of air aamitted along
the sides of the tobacco rod 60a. '
With regard to design technicues for the partially
filled, filler cigarett= 23 of the preferred embodiment,
heater energies and the amour_~ of heater-filler overlap can
be used to establish a=_d/or adjust delivery to a desired
"tar" level. According) y, in ~he course of desigr_ing a new
partially filled, filler tiger=tte 23, a selection o= rod
density in the tobacco plug 20 is c=nerally available for
achieving ~ de57.=ed deer°e O. preSSLr°_ drop at t=le free end
78 and/or t0 COntrO1 bcCki l C'vl, i n the same men-ler aS i5
achieved with a back=-ow _-leer 200a of the alterrate
embodiment 23a.
Referring now to Fig. 11, another cigarette 23b
constructed in 'accordance wig= another preferred embodiment
of the present invention inc'_udes a tobacco plug 80b which
comprises a low density port=on 310b adjacent tine void 91b
and a high density portion 320b adjacent the free end 78b of
the cigare=to rod 60b. The c=carett~ 23b is configured such
that the heater footprint S=3 overlaps the low density
portion 3_Ob of the tobacco plug Sob so as to obtain
enhanced celivery achievable with the lower rod densities.
The high density regior_ of c-~~ filler 320b is arranged to
avoid loose ends and to limi~ transmission of air axially
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through the rod 60b in a manner analogous to the backflow
filter 200a.
Presently preferred heater embodiments are show in
FIGS. 12-21. These heaters are suitable for any of the
cigar=tte embodiments heretofore described; that is the
fully filled, partially filled and filler free cigarettes of
Figur=s aa, Qb, 6a, 7a, 10 and 11, ar_d modificatior_s of
these cigarettes.
These heaters provide improved mechanical strength for
the recreated inser~ions, adjustments and removals of
Cigarettes 23 aT_ld 5=gulfiCantly imprOVe the g°n°ratlCn Of
aerc_sols from a he=_ed ciga-~tte while maintaining energy
reau=cements. It has been found t:~at the generated
aerosols tend to flcw radially inward sway from a pulsed
heater.
Generally, there are Dreferably 'fight heater blades
121 to provide eight puffs upon secruential firing of the
heats= blades 121, thereby simulating the puff count of a
conventional cigaret~e. Specifically, to heater blades 121
extend from hub 110 to fag a cylindrical arrangement of
heater blanes to =eceive an inserted cigarette 23.
Preferably, a gap 129 is de=fined between adjacent heater
blades 121.
It may be desired to change tae number Of puf=S,
and hence the number of heater blades 121, achieved when a
cigarette is inserted into the cylindrical receptacle CR.
This desired number is achieved by forming a desired number
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of heater blades 121. This can be achieved by providing
ecually or uneaually sized blades.
r
The heater fixture is disposed in the ori=ice 27 in
the lighter 25. The cigarette 23 is inserted, optional
back-flow filter 200 first, in the orifice 27 in tile lighter
25 into a substantially cylindrical space of the heater
fixture 39 defined by a ring-shaped cap 83 having an open
end for receiving the cigarette, a cylindr'_cal air chanr_el
sleeve 87, a heater assembly 100 including the heater blades
121, an electrically conductive pin or common lead lOaA,
WhlCh Serves a5 a COmmOn leaf fOr the cleat°_' a i ementS Of tile
heater assembly, eleCtriCal?y cOncuCtive ~CS?tiVe Di=1S Or
1 earls lOaB, ar_d the spacer. The bottom ire er sur=ace 81 of
the spacer stops the cigare_te 23 in a des_red position in
o i ra ao =rn~ i o ~ 1 rep
the hater f_xtu_.. 39 such that t___ he____ b_ad_s .2_ a__
disposed adjacent the cavity 79 in the cigarette, ar_d in a
preferred embodiment are disposed as described previously
with respect to Figures 1 to 11.
Substantially all of the heater fixtu=_ 39 is d_sposed
inside and sec~~red in position by a sn~=g fit jai th the
housing 31 of the front 33 of the light=r 25. A =orward
edge 93 of the cap 83 is pre'erably disposes at or extending
slightly outside the first end 29 oz the lighter 25 and
preferably includes an internally beveled o_r rour_ded portion
to facilitate guidin g the cigarette 23 into and out of the
heater fixture 39. The pins ~O~A and 103 are pre=erably
received in corresponding sockets (not shown?, thereby
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providing support for the heater fixture 39 in the lighter
25, and conductors or printed circuits lead f=om the socket
to the various electrical elements. Other pins can provide
additional support to strengthen the pin assembly. The pins
104A and lOaB can comprise any suitable material and
pre=erably comprise tinned phosphorous b=onze. The
passageway a7 in the spacer and the base 50 commur_icates
with the puff-actuated sensor a5 and the 1'_ghz sensor 53
senses the presence or absence of a cigarette 23 in the
lighter 25.
AS Seen in FIGS . 12 anc 13 , the heater cS52:nbI y 1 00 i5
preferabl y a monoii thi c struct~~== which cc.;.prises e' g'.~_~-t
heater blades 121 e=ctending frog a central = ~~:b 11 10 i n a
Symmer.rlCa1 arrangement Or, aS d_scuSSed belcw 1n re-°renCe
to FIG 19, is a non-symmetrical a=rangement. As best see.
i.n FIG. 13, the heater aS52LIlbly Ce=ineS a ge~e=al ly CirCtllar
insertion opening 360 having a t'_~_=oat 365 which directs the
inserted cigarette toward the coaxially defin=d cylindrical
receptacla CR having a diameter w=ich is less tan ir_sertior_
ODe_nillg 360. Insertion opening 30'0 is defines by respective
end portions 118B of the connecting sectio~s 118 of the
heater blades 121, and the throat section 365 is defined by
the portion of. sections 118 between con_nectinc edge 118A ar_c
end 1188. Insertion end 360 pre=erably has a diameter which
is Greater than the inserted c_carette 23 to guide the
Cigarette towards the receptacle CT_Z, and the reCeptaCl' C
has a diameter approximately equal to cigarette 23 to ensure
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a snug fit for a good t=ans==r of thermal enercy. Cigarette
23 pref=rably has a diameter which is approximately ecrual to
the rance of diameters known in the art_ Given acceptable ~
manufacturing tolerances for cigarette 23, the gradually
narrowing area or throat 365 in the transitior_ between the
distal end a_nd the receptacle CR can also serve to slightly
compress the cigarette to increase the thermal contact with
the su=rou.~idi ng blades 121 se=-v'_nc as an inner wall o. the
receptacle. By way of nor_-limiting example, inserticn end
360 p=e-era'.~.'_y has an internal d=amete. Of a~DrOX-.uaCely
0 .356 in. , _ 0. 02 in. and recept=cl a C;' pre===abl y . as an
interr~al d-ameter of app=ox'_mate_y 0.278 in., ~ 0.02 in.
The b'_ades 120 can be hewed _= ward to incr _ase t hermal
1~. ~ ~ rar o _...i r; 'na rar r
contac= w_t__ t_ a ciga___~_ by c~_. =s~__c__ng t___ diame___ o~
the cylindrical receptacle.
Each ~-shaped heater brace 121 comprises a first
section or leg 116A ext=riding at a first end from hub 111, a
con_nect~ rig section 118 coT_~~ acted to an ODDOSit° secor_d end
of the f_rst section or leg 116A, and a secor_d sect_on or
leg 1153 extending at a first erd from connecting sectior_
118 toward hub 111. First and second legs 116A and 113 are
separated by a gap 125 wrich can be relativ=ly cor_s~ant,
are preferably substantially parallel in any u:_rolled state
as in PIGS. 18 and 19 discussed below, are continuous =n the
direc~'_on cf cigarette inser='_on to reduce undesired
snagg=rig of the cigarett= ar_d are oriented to de°ine a
1 1 aI~G a - 'ta r i Ya ra
cy_in~ica_ r___ptacl_ C~ nor t___ i__serted c_ga__t__ 23.
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ConnectiTg section 118 has a curved joining edge 118A to
join oppcsing inner edges of the blade lets 116A and 1163
such t:-~at an elongated U-shaped resistive path is formed
which is substantially parallel with the longitudinal axis
4
of the inserted cigarette and extends alongside the
cigarett=, as discussed in greater detail below. Curved
joining edge 118A preferably has a curvature of
approxiraatel y '! 80° ~20° , so that a U-szaped blade is formed
and has a curvature which is concave toward the hub 111 and
cor_vex :.ward the insertion opening 360 . ~ __ fi rst end of
first b_=de leg 116A at hub 111 car_ have an _ncreased width,
with th. same approximate thickness, at portion 115
,relativ=_ to the remainder cf firs leg 110'3 to lower the
c~=rr~nt ~ens_ty and t'._ze power density at porti on 115 to
reduce c=mic heating of por~~on 1.5. P?so, this widening
increases the mechanical in=egrity of the Made 121 at hub
111.
A second end 122 0. second blade leg 1168 is
pref~ra~._y elevated relative to to main pcr~ion of second
blade section 1_5B in a step shape to facil_tate electrical
connect_oz with a respective positive p_n lOaB. More
specific_lly, as shown in F~Gs. 12 ar_d 13, end 122 comprises
three s'ctions, namely, a section 122A which is a
substant_ally pl~~.ar continuation of the main section of
second bade leg 1168, a transitior_ section .223 which rises
at an a-_gle as shown, and a correcting end section 122C
which is generally parallel with section 122A. The sections
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of end 122 can have a wider width than second blade leg 122B
for increased strength, to provide an adeav.ate contact area
for a positive connection at connecting end section 122C,
and to lower the current density and thus the ohmic heating
of end 122. End section 122C is preferably tack welded or
electrica'_ly and mechanically connected by any other
technicrue to positive pin lOS3.
Anotaer embodiment for achieving the positive
connections for the heater blades 121 is shown in FIGS. 1a
and 15. The connecting end 122 is pre=erably not step-
shaped as in FICs. 12 and 13; rather, it is a substantia'ly,
planar ex~_nsion of second heater leg 1153, which simpli=ies
the fabr_catior. discussed below. To decrease the
pOSSibility Of SIlOrtS al'1s1_ng from cCntaCt between the
pcsitive end 122 with the hub 111 and/or t:~!e section 115 of
first leg 116A as, e.g., the ir_serted cigarette is twisted
or other-,aise adjusted by tae smoker, an electric_lly
insulatinc ceramic coating 300 is applied to end 122, hub
11. and section 115, especially to the respect_ve facing
edces of t=ese elemen~s.
Pre=erably, the ceramic coating is applied by any
conventional techniQUe, e.g., plasma spraying, to the hub
111, conr_ecting end 122, and section 115 of first leg 1_5A.
The ceramic preferably has a relatively high dielectric
constant. Any appropriate electrical insulator can be
employed such as alumina, zirconia, mulite, corderite,
spine!, fosterite, combinations thereof, etc. Preferably,
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zirconia or ar_other ceramic is employed having a thermal
coefficient of expansion which closely matches that of the
' underlying metal heater structure to avoid differences in
expansion and contraction rates during heating and cooling,
s
thereby avoiding cracks and/or delaminations during
operation. The ceramic layer remains physically and
chemically stable as tile heater element is heated. A
thickness of, e.g., approximately 0.1 to 10 mils, or
approximately 0.5-6 mils, and more preferably 1-3 mils, is
preferred for the electriczl insulator. Preferably, a
portion of e_nd 122 is not coatec. Positive pins 10~B are
then corsectec as discussen to This exvosed ~ortior_. To
simplify maski__~_g, a coreesponding por~ion of section 115 is
likewise not coated with ceramic.
The cer ar,._c can also be a= plied, a . g . , in the same
plasma spraying step, in the gap 127 between the ends 122
and sections 1_5 of first legs llo'A and in the gap 126
between the e=ds 122 and hub 110 to form a ceramic hub
st=-uct~~re to increase the mechanical integrity oz the heater
assembly, as s:_owa in Fig. 15. T.e size of this ceramic hub
structure can be larger than shown. With or without this
additional ceramic applicaticr., the ceramic coating
electrically i_~_sulat~s the positive connecting ends 122, znd
the width gags 127 and 125 can be decreased while protection
against shorts is provided. Accordingly, the end section
122 and section 115 of first leg 115A can have an increased
area, thereby =urther strengthening the receptacle, and, in
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the case of the ceramic hub, increasing the skeletal
structure ~~d further strengthening the heat_r assembly. In
addition, such a ceramic coating smooths sharp edges
defining the gaps 125 and 127 to reduce the pot_ntial of
snagging and damaging the cigarette, especially during
insertion, removal and any adjustment by the smoker.
~te~jatively, the entire blade 121 and particularly first
and second 1 egs 11 6~ and 1163 are complete! y coated on one
surface, e.a_, the outer surface facing away from the
cicare_t°_, both the inner and outer sur°aces, andior the
ecges def'_ninc the gaps with a ceramic layer, e.g.,
ra
approx'_mat= 1 y 2 mil . of zirconia, to st____gt--_-- the heat=r
blades, mainta=n~nc gaps if CleS~r°.~.. The b13Ge5 ~2~ Can
accorcingly be thinner, e.g., approxir.~at=ly 2 to
_'. 6 mil_, thereby increasing the r~sis~=~.ce of
approx_mat__y
the hs~t=r path ar_c perm-sting the blades to be wiser for
increased thermal interface with the inserted c=gar=tte 23
while maintaining t'_he same overall blade r=sis~ance. This
increased blade widta, along wish the ceramic layar, further
Strengthen the heat=r St=,assure. A1S0, the Cera:.ti C COat3.ng
on the outer surface of the blades 121 facing away f=om the
insert=d cigarette may pr=vent thermal losses from a heated
blade t0 t. a c~mble__~_t. The Ce"'amiC is pre.eraDly applied V1a
plasma spray'_ng or any of =er method described in the related
applicatior_s and pr=ferably is applied via electron beam
physical vapor deposition to avoid inducement of r=sidual
stresses which -may be induced during processing in plasma
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spraying from sur=ace t=eatment and/or pa=title im=act.
Each blade 121 fo .,s a resistive heater element. More
specifically, the first end 115 of first blade sec~ion 116A
is electrically connected to the negative terminal of the
power supply, and more specifically is an integral extension
of hub 111 or is mechan_cally and electrically car~ected to
hub 111, which in turn is in electrical and mechanical
connected to negative terminal pin 104A via tac:c welding or
another techniQU°_ such as braz_ng or soldering. P=eferably
two termi=al pins 10~A are used to provide a balanced
suoDOrt . since t'_he nega~ive a. d posi rive corp.=coons also
sense to mechanically s~~porc the he=_te- . The hub 1 11 thus
font=i or_s as an elect='_cal common for all of t'_~_e heater
_n - ~o ; o,-.. :-.o
bl ades 12_. any o. t___ embod_m___ts, t___ negat ve
connectior_ for each hea=er caz be made indiv=dual_y by, e.
g., an appropriate nega=ive contact deposited on an end of
the heater opposite the respective positive cor_tact areas
122.
A respective positive cor_nection for e=c'._z he_ter blade
121 is made at connecting end section 122C of the second
blade sec=ion 115B as discussed. Connecting e-d section
122C is electrically i_=plated or insulated from common hub
110 by a gap. 127; f°om fi=st blade section 116A, and
particularly first end 115, of the associated he=~er blade
120 by a gap 125; and from the adjacent heater bl=de by gap
131 to avoid shorts an d to permit t:Zermal expa ~sion. In
addition, the discussed ceramic coatings are optionally
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annlied. Alte=-natively, connecting end sections 122C are
respective?y connected to ground.
The discussed positive and negative connections
a
provide a resistive path, and more specifically a circuit,
for current applied from the source of electrical energy,
e.g., via tine control circuitry, to a particular blades)
120 upon activation of the smoking system by a smoker's
draw. The primar~r heated area of the blade comer-ses first
blade leg .16A, edge portion 118A and second blade leg 1163.
According'1 -y, a portion of th a 1~Se-te.~. ClCc=etta 23
underlying and ccntacti:g the actuated blade 12'! extending
alongside will be heated in an outer sur=ace pattern
core espond_ng to t'_he heat=d por Lion of the bl ade , i . a . , i n
an elongated U-shape ccrr'spond=ng to the overly_a.g blade,
primarily via conductior_ and radi ation, wit'_~_ some convection
likely occurring. In additior_, the portion of th= inserted
cigarette between the lags, i.e., underlying ga= 125, is
heated by overlapping or intersecting, cumulative radiative
and conductive heat transfer _rom both leg 115_'-- and leg
116B. If cap 125 is too larg°_, desired overlapping will
not occu_ and the pe=tion of the ir_ser~ed cigarette
underlying gap 125 wily not be adeQUately heated. Also,
radiative and.~conductive heat will heat st=ip pc=tior_s of
the inserted cigarette slightly beyond the outer edges of
heater blade legs 116A and 116B. The various heated
portions together cor_stitute a heated regio: of the
cigarette 23 that exte_Tds from slightly beyond the outer
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edge of leg 1 1 6A, beneath l eg 17.6A, across gap 125, beneath
leg 1163, and slightly beyond leg 1163 ef an actuated blade
121 and which correspond to a puff of generated tobacco
flavor. The size of the he_ted portion is dependent upon
the blade geomet=-y and heat'_ng characteristics as well as
the amount and duration of the er_ergy pulse. Preferably,
the heater blade is sized and thermally designed to
ui timately heat a segment o. the inserted cigarette having
sufficient s=ze, e.g. , 18 scruare mm, to generate an
acceptable au=f to the smoky= in response to a puff-act.-G~.°d
energy pulse.
Relativ'1 y 1 arger bl ad' end areas _.S and 1 22 fc=~r..i~g
a part of the Current pS,t!1 a.°_ not he=teG t0 these oper?t7.-1g
temperatures since their r=latively la=ger vcl~.ames lower
to°_ curre~ ' deT_1S ity, and thL:S lOWer the CtlmiC he~tlnQ . :~ ! SO
,
a section of connecting end section 118 is pct heated to
these operating temperatures since the h=sting path tends to
foil ow edge 11 8A and tills section constitutes a rel at'_vely
larger volume and accordi=~c'_y has a 1 ow.r current de_~_si ty,
aid thus has a lower ohmic heating, than the edge 118A and
imriediatel y adj scent sectior_s . To fur t'_'_~_er reduce u_ndesir ed
heating of the remainder of connectir_g portion 118, or_e can
(1 ) increase ~tiie thic?c~-iess of the mono_ithic material of
portion 118 relative to cur-~ad edge 118A in a region 118C to
further reduce current dens'_ty and ohmic heating, as shown
in FIG. S, (2) perforate po==ion 118 to reduce ohmic and/or
heat conduction paths, and/or (3) add an additional heat
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sink material 119 onto portion 118 to red~~ce the=-mal
trar_s~er to the portion, as shown in rT_G. 6. To achieve
this heat sink function, a thermally non-conductive '
material, i..e., a thermal insulator such as a ceramic, is
applied. Examples of suitable ceramics include alumina, '
zircor_ia, a mixtura of al umina a~=d zirconia, mul ite, etc. ,
as is the case with the heater blade coating. ~~y of these
modifications should be evaluated for any adve=se effect on
the mechani cal integrity of con_~_ecting portior's 1~ 8 wizich
sup~c-t the heater assembly 100 and define an i:sertion and
withdrawal opening for tile cigare~~e.
After a heat.. blade 121 is pulsed, .here a a
r~cr~=r a
~______rmined minimum time be=ore a subsequ_.t puf= is
perm_tted. Premature heating of a porticn of the cigarette
could also result in undesirec and/or part_al aerosol
generation or heat-induced negradation of tie cigarette
portion prior to the desired heating. S;ibsecue__~_t reheating
of a previously heated portion can result -n undesired
flaw=s and tastes being evolved.
If a longer puff is desired than is obtained by a
pulsiag of a sing-a heater blade, teen the cone=of logic is
Configured t0 fire another heater or addit=oval heater
blades) immediately after the pulsing of the ir_itial heater
blade, or during a final portion of the initial pulsing, to
hea~ another segment of the c'_carette. The additional
heat.. blade can be a radially successive heater blade or
another heater blade. The heater blades should be sized to
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obtain the total desired number of puffs of a desired
duratior_.
In one embodiment, the number of heater blades 121
corres~cnds to the number of desired puffs, e.g., eight. In
another embodiment, the number of formed heater blades 121
is twice the number of puffs, e.g., there are sixteen
portions with heaters for an eight puff cigarette. Such a
conf igu-ation permits different firing segue~.ces than the
normal successive firing of approximately 2 seconds, and
preferably the radially seruential firing se~~ence for an
embodiment wh°.ein the number of heatinc blades 121
correspcnds to the puff count. .or exampl_, the logic
C1rC111i. -rCan GlCtat°_ that tW0 Ci=Cumferentially ODDOSit°_
,- bl 1 ~ heater blares se~ara=ed by 180° on
heate_ ades 2_, i.e.,
the tu~_, firm simultaneously to jointly hea= an adequate
amount of the cigarette to generate a puff. Alternatively,
a first firing sequence of every ot'_her heater blade 121 for
a cigar=tte is followed by a secor_c firing seruence 'of the
intervening heater blades 121 for the r_ex~ cigarette.
Alternatively, this first firing seauence can be repeated
for a predetermined life cycle of numerous cigarettes and
then t~n second f i ri ng seauence in' tiated. Pr_y combinatior_
of heat=r blades can be employed. The number of heater
blades can be less than, equal to, or greater than the
number of puffs of a single er,.ployed cicarette. For
example, a nine blade system can be employed for a six-puff
cigarette. wherein a different set of six heaters is fired
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for each subsequent cigarette and the associated set of
remaining three heatars is not fired.
The heater assembly 100 is electrically and
mechanically relatively fixed at one end via the welding of
pin ( s ) 104A to hub 11 0 and of pins 1048 to ends 122 . Pins -
lOaA and 1048 are preferably pre-molded into plastic hub, or
otherwise fixedly conr_ected thereto, ~referably in a manner
to minimize air laakage. Pre_erably, this fixed end is
opposite the insertior_ opening 360. The connecting sections
118, and specifically cpposite ends 1133 opposite connecting
edges 118A, define the insertion open_ng 360. End sections
1188 can -late outward to de=fine a throat section 365.
Blades 121 then narrow =tom this t'_roat section to define
an in=ernal diameter which is slight_y less than the outer
diameter Of the =nSer='d Cl.gcrette 23 at, e.g., t__~.e blade
midpoir_c to provide desired th=rural contact, i.e.
compressive forces, between the blac=s and the cigarette.
End s=ctior_s 1188 are fre= to expand when heated, i.e., end
sections 1188 are not =fixed. More specifically, each end
118B is positioned within a corresponding chary-~.el 210
located in in~mer wall 201 0~ lighter end cap 83. More
speci=ically, the racially outward movement of end sections
1188 of inwardly biases blades 121 are arrested by ends 1188
contacting radially outward walls of channels 210, thereby
establishing a boundary for the biasing and de=fining tile
inward bias. This inward bias may supplemented by the inward
fabrication bias as discussed. As shown, inner wall 201 is
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flared outward to pe=-mit inser Lion of a portion of blade
ends 1188. The radially outward wall of channel 200
contacting end 1188 is sized and shaped to permit insertion
of an adeauate amount of blade end 118B such that the blade
end will not exit c:za_rne1 210 during heating or cooling of
the blade or inse=tion or withdrawal of the cigarette. If
desired, this radially outward channel wall is provided with
a rest, e.g., a trapezoid, which contacts the ends 118B. In
an alter~-~ative embodiment, a portion 118D of blade end 118B
is rounder, and more specifically elliptical, prior to the
rose=red end portion 118B. This rounded portion 118D
perm'_ts the inserted portion to pivot within channel 210 in
respor_se to ther,«al 1 y or mechani call y induced moments ,
then=by maintaininc the inse=ted portion of the blade end
within c:~annel 210. Additorally or alternatively, blade
ends 118B are more rounded.
.n a first embodiment shown in FIG. 3, channel 210 is
sized suc'.~_~_ th at end 11"03 of the heat=r blade 121 can expand
in a tra=slating mar.~~er, i.e., toward end face 202 of
channel 210, upon insertion of the cigare'te 23 and/or
heating of a blades, so that desired contact between the
cigarette and the blades is achieved. Such an arrangement,
wherein one end of the blade is free relative to the
oppositely located hub, ~e=snits mechanical displacement
and/cr thermal expansion and contraction of the heater
blades 121 in the longitudinal direction upon respective
y cigarette insertion/witharawal and/or blade heating/cooling,
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thereby reducing stresses. In a second embodiment shown in
FIG. la, a_n abutment 20a, which may be trapezoidal, is
located within the channel 210 such that as heater blade 121
expands thermally upon heating or displaced as cigarette 23
is inserted, end 118B contacts abutment 20a and establishes
a pivot poi nt to al low blade 121 to bias inwa=3 toward the
inserted cigarette 23, thereby reducing stresses on the
blade and increasing desired the=.pal contact, i.e.,
compressive forces, between the blade and the cigarette. By
pivct point, it is mear_t that the blade 121 is free to
rota=~, but pr=ferably not translate, at this abutment 20~.
The heater assembly 100 is thus ~r~f~=ably a
mono 1 it =i c st=-uct~_r= which optional? y is coaxed w_th a
Ce~araiC aS Ci SC11SS°.~~. The hub 11 1 and heater bl adeS 121 are
fabr_Cated irOm c material having desiret'. elect=iCal
resistanC°_ a=J.d Str°_~TJ.Cth. For example, mat°_?'ial S
having
electr_cal resistance in the range of approximately 50 to '
approx'_mately 500 ;.cohm.cm, and more preferably approximately
100 to aDDrox'_mate?y 200 E,cohm.cm are Dreferrec, such that
temperatures c. app=oximately 20.0°C to approximately 1000°C,
and preferably apprOXimately a0~°~.' t0 apprOXlmately
950°C,ard mcre preferably approximately 300°C to
approxir"ately 850°C are reached by the activated blade 120
in approximately 0.2 to approximately 2_0 sec. with a pulse
of app=oximat_ly 10 to approximately SO Joules, more
preferably approxisaoely 10 to approximately 25 Joules, and
even mcre pre=erably approximately 20 Joules. The mate=ial
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should be able to withstand approximately 1800 to
approximately 10,000 such pulses without suffering failure,
significant degradation, or undesired sagging of tine blades
121.
' The materials of which the heater blades 121 are made
.~~.L'I ~. _L_-
are pre=e_~~y c.~osen to ensure reliable repeated uses of at
least 1800 on/off cycles without failure. The heater
fixture 39 is pre=erably disposable separately from the
lighter 25 including the power source 37 and the circuitry,
which is preferably disposed of offer 3600 cycles or more.
The heater materials and other metal 1 is compor_ents are al so
chosen based on their oxidation resistance and general lack
of reactivi~ies to eaure that they do not cxidize or
otherwise read with tile cigarette 23 at any temperature
likely ~o be encountered. If desired, the heater blades 121
and oti~._r metallic components are encapsulated in an inert
heat-cor_ducting material such as a suitable ceramic material
to furt'_her avoid oxidation and reaction.
Mcra pre=erably, however, the heater blades 121 and
other r"etallic components are made from a heat-resistant
alloy ~=~at exhibits a combination of high mechanical
strength and resistance to surface oxidation, ccrrosion and
degrada~=on at high temperatures. Preferably, the heater
blades _21 are made from a material that ex'~_bits high
strength and surface stability at temperatures up to about
o ., _
pence nt of- tire== mal~in5 points. such alloys include
those commonly referred to as super-alloys and are generally
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based on nickel, iron, or cobalt:. ror example, alloys of
primarily iron or :Lic.~ke~.1 wi.t:h <~~.uminum and yttrium <zre
suitable. Prefera.b:l.y, the alloy of the heater blades 121
includes aluminum vc~ further imp:ro,,re the performance' of the
heater el~~~ment , a . ~:~ .. , by prc>vidinc~ o~:idat ion resistance .
Preferred materials include _iron and nickel aluminides
and most ~~referabl ~~ the alloys d:iscl.osed is commonly
assigned n~.S. patent No. 5,~95,7c>0 and especially U..S.
patent No. 6,280,632.
Several elemeat:s can be~ used as additions to the Ni3Al
alloys. 13 and Si are the principal additions to the alloy
for heaterr layer l?~; . F3 is thouc~tlt= to enhan~~e grair~
boundary strength :::znd is most effective when the Ni3Al is
nickel rich, a . g . , A=1. <_ 2 4 a t . => . S i i:~ not added to the
Ni3Al allc>vys in la3:ge quantities since addition of Si beyond
a maximum of 3 weight percent will form s:ilicides of: nickel
and upon oxidation will lead to SiO.{. The addition of Mo
improves strength at low and high temperatures. Zirconium
assists in improving oxide spallinc~ resisi~ance during
thermal circling. r'~lso Hf can be added to improve high
temperature st:rengt::ra. Preferred Ni;Al allc>y for use as the
substrate 300 and aresistive heater :122 is designated IC-50
and is reported to comprise approximately 77.92% Ni, 21.73%
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A;. 0.34°<-~ Zr and 0.01% B in "Processing of Intermetallic
Aluminides", V. Si.kk<x, Interrneta:liic Metallurgy and
Processing Intermeta,llic-Compounds, ed. stoloff et <~1., Van
Nestrand F~einhold, N. Y., 1~~94, 'table 4. Various elements
can be added t.o the :irc>n ali.~im.imidE=. Possible additions
include Nb, Cu, Ta, 1r, 'fi., Mn, :3:i, Mo and Ni. The heater
material can be the Haynes~~ 214 alloy (Haynes~ Alloy No.
214, a nickel-basei alloy containing 16.0 percent chromium,
3.0 perce~~t iron 4.p percent aluminum, traces of yttrium and
the remainder (app-~~c:~ximat:ely 75 percent) , commercia7.ly
available frorn Hayc~c:.~~ Intern.ationa-1 of Ko:komo, Indi~ina) ,
Inconel~ 702 alloy, MCr~Aly alloy, -~eCrAlY, Nichromet~ brand
alloys (54-80% nic.~el, 10-20% chr_ornium, 7-27% iron, 0-11%
copper, 0-5% manganese, 0.3-4.6% silicon, and sometimes 1%
molybdenum, and 0. ~?t:~% titanium; Nzchrome I is stated to
contain 60% nickel, 25° iron, I~1=s chromium, and 2%
manganese; Nichrom~= I:.T, 75% nickel, 22% iron, 11% chromium,
and 2% manganese; ~:aruci Nichr~ome III, a heat--resisting alloy
containin<~ 85% nicl~f:~i., and 15= chromium) , as described in
commonly assigned v.J.~. patents No:~. 5,666,978 and 5,388,594,
or materials havin~~ si.mi.lar properti..es.
As shown in FLG. 12, the heater blades 121 are arranged
to extend symmetri<~ally from hub 111. Alternatively, non-
symmetric arrangements are employed. For example, the
plurality; e.g., s-ix or eight, of heater blades 121
can be subdivided into, a . g . , t.wo equal ly numbered
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subgroups of, e.g., three or four, heater blades. The
heater blades in each subgroup are separated by cans 131 as
discussed previously. The subgroups are separated by a
wider gap 13 5 , as shown in FIG . 19 in tile ur_r of l ed flat
state. Gap 135 is defined such that conductive and
especially radiative heat transfer from adjacent blades 121
of adjacent subgroups is minimized to the portion of
cigarett°_ 23 underlying the can 135. Accordingly, gap 135
provides a wider unheates and robust portion of the
Cigarette which is stronger than unheated port=or_s of tile
cigarette underly'_ng narrower gaps 131, wereby the column
strengt~ Of Cigar°_t=e 23 i = lmprOVed t0 Gi d i n Y'°T.110Va1
Of
the cigare~.te a=t=r smoking and consec-4e_nt he=c-ng, and
weakenl= g, Of pOr=10115 . I. CeSlred, tile ! Ogi C Cc-1 activate
more thaw one heater simult=neously in the symmetric or non-
symmetris arrangement.
The present invention having two heater legs 116A and
116B separated by a gyp 125 results in s=gnificant
improvemen is i n the amou=_t of aeroso_ gene=at°_d whe:l
compares to tile amount generated by a sold heat=s element.
A .solis heater achieves good thernal transfer with the
cigarette; however, mass tr=nsfer of aerosol into the drawn
air flow is compromised by the solid s~ructur= blocking
optimal entrainment of air located outside of the cigarette
into t=a cigarette, especially if the enclos~r=_ of the
smoking system housing is provided with perfor=tions for
communicating air outside cf the enclosur= to the cigarette
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outer surface. A heater accord_ng to the present invention
having the same volume as a solid heater but having a larger
pe=imeter results in a higher opportur_ity for entrainment,
e.g., due to gap 125, and accordingly results in an improved
flavor delivery per unit of energy to the blade 121. As
discussed, gap 125 should sized to provide optimal radiation
overlap for a given blade geometry_ Since a higher amount
of aerosols are generated, the reauired mass of the blades
can be decreased while genes=tiring the same desired amount of
flavors, resulting in a 1; ghter uni t and a decrease in the
o -~ i z A_ or o '1 n
energy r=a_ui red to ad_cua~__ r heat the h_~t blad_s 12_ a__d
1n serted Ci gazette, wh i Ch f'.7.=i..~"ler reduCeS the Wei ght Of t:le
urlt SlnCe the pOwe. S~v'n.'.=.~.e, e.g. , ~'ratt°1'.eS, Ca~Tl De
s.-.,tiller. By way of nor_--i~.iting example, gap 125 can be
i
a-pprOXlmtitely 0.020 ln., _ apprOXimately .005 1n. Wid°_
bl tide legs 116A and 1 1 6B ca.! be approxi mutely 0 . 0125 in. to
approximately 0.017 in., _ approximately .005 in. wide and
approximately 0.55 in., _ approximately .005 in. long; and
approximately .008 in. to approximately .010 in. thick, ~
approximately .005 in.; and the length from the hub 110 edge
to the tip of connecting section 118 can be approximately
1.062 in., ~ approximat_ly .0625 in.
It has been found that a primarily transverse or
radial air flow reltitive to the inserted cigarette results
in a mor= desirable smok°_ generation than a primarily
longitudinal flow. The gaps 125, 127 and 131 provide
pathways for air to be craven into contac~ with tile inserted
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cigarettes. Additi~~na:l. air passages are provided to
optimize the transverse air flow b_,~ perforating sect=ions of
the heater blades.
Another embod.:i.ment of Blade geometry is shown in FIG.
16, wherein both first .Leg 116A and second leg 116B are
serpentin~_~ shaped. 'I'~ne ::er~~entine :shapes of legs 116A and
116B are parallel such that the legs are evenly spaced and
gap 125 i;~ also ser_~pentine-~~haped. Such a serpentine shape
increases the bladr,.= perimeter, axed thus improves the aerosol
entrainment. This serpentine shape is described more fully
in as described EP -F~--0, 67_5, 411 and i.r~ common:ly assigned U. S .
patents Nos. 1,666,,978 and 5,388,594.
A first preferred methc:d of fabrication will now be
described with ref~.~rence to FIGS. 18 and 19. The
fabrication steps t::iefined herein may be performed in any
desired order to at:hieve manufacturing speeds, materials
savings, etc .
A sheet or stv-ip of an appropriate material having a
thickness of, e.g., approximatel~~ a: to approximately 20 mil,
e.g. approximately :1;; mi.l, is formed to define a plurality
of blades 121 extending generally perpendicularly via
respective first b::Lade sect:ic~ns 11.6A, and particularly via
respectivE: first ei:ud sections 1.1F,, from a generally straight
section 111A in a cromb-like arrangement. The blades 121 are
substantially para:l.l.el to one another with gaps 131 located
between the opposi.xug edges second blade section 116E~ of one
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blade ar._d the first blade section 116A of ~. adjacent
_ blade. As discussed, the blades 121 are either
symmetrically arranged with equal gaps 131 therebetween as
shown in FIG. 18, or are non-symmetrically arranged, e.g.,
with equal gaps 131 between adjacent blades 121 de=fining
subgroups 121 A and 1 213 of blades a_nd a 1 arger d=stance 133
between the two subgroups oz width X as shown in FIG. 19.
Note that straight section 111A has two end port_ons with a
length o. at least half the length of one half X to form a
second d_stance 133 upon rolling. T':ese end port-ons should
be longer t~az X to provide an over l ap =or conr_ec=ion. By
way of ~on-1 imi tir_g example, gap 1 31 c=~ be a= ~roxir..ately
0 . Oa0 i n. , _ . 005 iz. wide in any o. t .e embodime =is a .c gap
135 can be ap proximate! y 0 . 125 in . , _ . 005 in. wide i ~ the
non-symmetrical embodiment.
The blades are configured as discussed previously to
fog connecting section 118 and the legs 116A and 1153.
This fOrmatlOT_1 Of the sheet Cr Sv.~ i D Of mc~ar131 i nt0
the described configuration is perfo=-.ned by any car_ventional
technique suc~! as stamping or cutting, a . g. , wi =h a CC2 or
Yag laser. _' a strip format is employed, the number o.
heater b? ades.. 121 formed from the scr_r~ can axcee,- the
re~uirea number for a single cylindrical heater arrangement.
The str=_i ght strip is then cut, if necessa=_~, to form
sections illA having the desired nur.;oer of heater blades 121
extending th~r~from. If employed, tine step shape of
sections 122A, 1228 and 122C is fo~:ed via stamnicg.
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If employed, ceramic coating 300 is then applied by
mask_ng the stamped profile and, e.g., thermally spraying _
the coating onto sections 111A, 115, 122 or tie entire blade
or any portion thereof to form the desired pattern as
discussed. Alternatively, the ceramic coating is applied
after the rolling step by this procedure or, if desired,
prior to formation of the blades . As is know_~_, appropriate
maskings are applied prior to performing eat: of the steps
of heater and ceramic depos_tion to de='_ne ar_as of
application.
The section lil A i s the_~_ rol 1 ed to _crn round hub
111. The section 111A can be rolled in eit=r direction.
Pre-erably, section 1_lA is ro_led such tha= the pcsitive
contacts 122C at eTd sectior._ 122 are on tile outer sur_ace o.
the formed cylindrical neater, i.e., the site opposite the
cigarette, to simpli=y correction with pins 1048 and to
avoi d damage during ir_sertion a~lCs removal of the cigarette.
The rolled section can be roller to a smaller diameter than
its ultimat= desired diameter and is inser=ed into the
fixture. The rolled section t=en expands aid is further
held in shape by the electrical conr_ections. "terr_atively,
the rolled section is joined, e.g., via any welding
tec _~~ iw.e such as spot welding or laser weldi-c, to form the
hub 111.
Preferably a bias is imposed on each _lade 121 such
that legs 116A and 110'3 and corm ecting edge i=3A wi'_1 exert
a compressive force on the inserted cigar_~te when the '
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heater assembly is formed, as shown in FIG 13. This biasing
preferably occurs prior to rolling, but may be implemented
after rolling. Th_s biasing increases the thermal contact
. between the heater blade and the inserted cigarette to
imarove thermal trar_s~er efficiency.
Thermal trar_sfer efficiency is also improved by
optimizing the amour_t of surface areas oL the blade legs
116A and 1168 which are in an efficient thermal relationship
with the underlying c=gazettes. As seen in FIG. 17A, the
undersi c.es 117 of legs 1 1 6A and 1168 (leg 11 6A is show.. by
way of example) is planar, i.e., flat i~ a transverse
directier_ of the blade leg ir_ the discussed embodiments. To
i mDrove the t'_~_er:nal transfer r=1 at ions hip, the underside 117
a shaped in various non-pla=ar geometries, e.g., an angle
or curve to maxim=ze the surface area of the heated leg
relativ° rto the cigarette without undesirably increasing the
volume, and hence ur_desirably lowering tile current density
and resultant ohmic heating of the heater leg, as
respectively depicted in F_C-s. 17B and 17C. The shaped
underside 117 preferably does not pierce any part o. the
cigarette 23 to avoid weake=~ing and possibly r_pping the
cigaret== during insertion, adjustment or removal. Rather,
the midpoint or apex of tile underside 117 contacts or is in
close ther-.nal proximity to c_carette 23, and the rema_nder
cf unders_de 117 is in a radiative thermal relatior_ship with
cigaret=a 23.
this underside shape is achieved by
Pr=f=rabl y,
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stamping the legs 116A and 1163 of the blades 121 in an
unrolled state. This stamping can occur ac the same time as _
the stamping to achieve the bias discussed above. This
stamping to shape the underside also increases the strength
of legs 116A and 116B, thereby avoiding undesired shorts and
deformations.
A second method of fabrication will now be described.
A tube of appropriate material is provided. The blades 121
are then formed via any techniaue such as laser cutting.
Alternatively, the blades are forned by a swaging technique
ral ~~ ~ arl i 'r~ T,Ibe t0
wherein an internal' mand~__ is s_=t_... nto t__e t
form the di scussed blade profi les a__~_d t~en another swage,
e-ther internally or exterr_ally, is employed to cut the
profile. A ceramic coating 300, .f ces=r=d, is provided as
discussed to the profiled tube.
The present invention also minimizes potentially
damaging thermally induced stresses. Since the heater
blades 121 and hub 111 are monolithic, stresses a=ising from
intercer~ections of discrete portior_s of a heater element
are avoided.
The various embodiments of the present iriJentiOn are
all des_cned .to allow delivery of an effective amount of
flavored tobacco response to the smoker under standard
conditior_s of use. Particularly, it is pr=sently understood
to be desirable to deliver between S and 13 mg, preferably
between 7 and 10 mg, of ae=osol to a smoker for 8 puffs,
each pu== being a 3S ml puff having a two-second duration.
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It has been found that, in order to achieve such deli~rery,
the heater elements 121 should be able to convey a
temperature as discussed when in a thermal transfer
relationship with the cigarette 23. Further, the heater
blades 121 should preferably consume the discussed energy.
Lower energy recuirements are enjoyed by he=ten blades 121
that are bowed inwardly toward the cigarett_ 23 to improve
the thermal transfer relationship.
Of course, the heater resistance is also d_ctated by
the pa=ticular power source 37 that is usec to provide the
necessary electrical energy to heat the hea_e= b'_ades 121.
For example, the above neater element resistaaces correspond
to embodiments where power is sunnlied Lv fou= nic~cel-
cadmium battery cells cors~.ected in se=i es w'__h a total ncr_-
loade3 power source voltage of approximately ~.8 to 5.8
volts. In the alternative, if six or eight such series-
-connected batter ies are used, the heater bl cedes 121 should
preferably have a resistance of between abou~ 3 i2 and about
S ~2 or between about S ~2 and about 7 f2, res= ecti vel y.
Another embodiment a50 of tine preser= invention is
shown in FIG. s. 20 and 21 comprising a plurality of heating
elements a51. . Each heating element ~S1 is in the shape of
an elongated °U", each having both of its errs a~2, X53 of
respective legs connec_ed to the side wal? of cavity a30
adjacent end wall aa3 of cavity a30. Each respective end
452 is individually corzected to tile control circuit=y, and
' ultimately to the source of electrical ever=y, for
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individual actuation of heating elements 451, while ends 453
are connected in common to ground. While ends 454 adjacent _
the mouth end of cavity 430 are not electrically connected,
and thus need not touch the side wall of cavity 430, they
are nonetheless tu=-ned toward the side wall of cavity 430,
as shown in both FT_GS. 20 and 21, to provide a lead-in for
the disposable pcr_ion, i.e., the inserted c=garette,as
discussed above. It s~-:oul d be noted that in FIG. 21, the
uppermost and lower,cost elements 45? arm shown c:a throuch
their U-shaped tins 454.
In another embedim°nt 470 show~ in F=GS. 22 and 23,
heating el ements 471 ar=_ spaced somewh at fur ther from t'_'_~_e
wall of cavity 430, ar_c each is provided with a somewhat
sharper °V" tip E72, as wel 1 as wit-! fo 1 d 473 to inc=~ase
their rigidity. In this way, heating elements 471 actually
pierce and exter_d =nto the disposable portion to provide the
desired intimate the ~.al contact. The open-cell foam
structure described above is pcrtiCUl~rly well-suited for
such an embodiment. I~ this embodiment, because heating
elements 471 are s~acsd further from t=a side wall of cavity
430, ends 452, X53 are not at~ached to the side wall of
cavity 430, but to its end wall 4=3. Preferably, the
connections of gads 452, 453 to e~c wall 443 are made
through spacers 430 which are ~ot conductive of e=thers he_t
or electricity. In this way, a wiping action wipes residue
past ends 452, 4~3 and onto spacers 4c0, where the residues
are not repeated, as described more fu=ly in U.S. Patent No.
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5, 249, 586. Perfox,~~t=:LOrus 412 are provided in the wa_Ll to
allow outside air to be drawn th:rou<1h portion 420, as
described more fully in U.~. Patent No. 5,249,586.
Many modifications, substitutions and improvements may
be appareit to the tl~c-illed artisan without departing from
the spirit and sco~E~ of t=.he present invention as described
anal defined hE=rein ,:~ncl in t:.r~e X01=l.owi.ng claims. For
example, the decur:l.~_nc~ step may be performed before the
cooling step in a modification of the portion of the process
described above wil~ln referer:.~e to FIG. 5B.
