CA2218595C - Cigarette and heater for use in an electrical smoking system - Google Patents

Abstract

A cigarette (23) comprises a tobacco rod having filled and unfilled portions arranged so that electrical heater elements (37) may overlap both portions. The rod includes a tubular tobacco web. The web is constructed by converting tobacco feedstock into a continuous sheet of tobacco web and converting the continuous sheet of tobacco web into one or ore bobbins of tobacco web suitable for automated manufacture of cigarettes. A heater (25) comprises a supporting hub and electrically resistive heater blades (37) defining a receptacle (27) for an inserted cigarette (23). Each blade comprises first and second heater blade legs each having a first end and a second end, and a connecting section connecting the second end of the first leg and the first end of the second leg. The blades (37) are heated by a resistive heating circuit and heat the inserted cigarette (23). The legs are separated by a gap to permit entrainment of flavour substances upon drawing.

Description

R'O 96/32854 PCT/US96/05417 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.
SUBSTITUTE SHEET (RULE 26)

2 _=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 SUBSTITUTE SHEET (RULE 26) 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 WO 96/32854 PCTlUS96l05417 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 SUBSTITUTE SHEET (RULE 26) 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 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 SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE 26) :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 SUBSTfTUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) WO 96!32854 PCT/US96/05417 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 SUBSTITUTE SHEET (RULE 261 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 SUBSTITUTE SHEET (RULE 26) WO 96!32854 PCT/US96105417 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.
SUBSTITUTE SHEET (RULE 26) 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;
SUBSTITUTE SHEET (RULE 26) 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~
SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) R'O 96/32854 PCT/US96/05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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 R'O 96/32854 PCT/US96/05417 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 SUBSTITUTE SHEET (RULE 26) 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.

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 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 SUBSTITUTE SHEET (RULE 26) 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 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 SUBSTITUTE SHEET (RULE 26) 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 _ SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE ~6~

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 SUBSTITUTE SHEET (RULE 26)

4 . PCT/US96/05417 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 SUBSTITUTE SHEET (RULE 26) WO 96/32854 , PGT/US96/05417 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) 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) 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) 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) 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) 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) 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) 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 SUBSTITUTE SHEET (RULE 26) WO 96/32854 PG~'/US96/05417 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) 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) WO 96!32854 PCT/US96/05417 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) 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 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 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 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 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) 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 SUBSTITUTE SHEET (RULE 26) 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.

WO 96/32854 PCTlUS96/05417 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"
SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SNEET (RULE 26) WO 96/32854 PCT/iTS96/05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) WO 96!32854 PC'T/US96/05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) WO 96!32854 PCTlUS96/05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE 2~J

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 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 SUBSTITUTE SHEET (RULE 26) WO 96!32854 PC"TJUS96/05417 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, SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) WO 96!32854 PCT/US96l05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) -WO 96/32854 PC'T/US96/05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) R'U 96/32854 PCT/US96/05417 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 SUBSTITUTE SHEET (RULE 26) R'O 96/32854 PCTJUS96/05417 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 SUBSTITUTE SHEET (RULE 26) 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, SUBSTITUTE SHEET (RULE 26) WO 96!32854 PCTli1S96/05417 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 SUBSTITUTE SHEET (RULE 26) 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 SUBSTITUTE SHEET (RULE 26) l 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%

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 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 SUBSTITUTE SHEET (RULE 26) WO 96!32554 PCT/US96/05417 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 SUBSTITUTE SHEET (RUL.E 26) 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 WO 96!32854 PCT/US96/05417 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.
SUBSTITUTE SHEET (RULE 26) 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 ' SUBSTITUTE SHEET (RULE 26) WO 96!32854 PC'TIUS96/05417 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, SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE ~6) 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 SUBSTITUTE SHEET (RULE 26) 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.
SUBSTITUTE SHEET (RULE 26) 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.

Claims (79)

1. A cigarette and lighter adapted to cooperate as an electrical smoking system, said cigarette comprising a tube of tobacco web, partially filled with cut filler tobacco so as to define a filled tobacco rod portion and an unfilled tobacco rod portion (91), said cigarette (23) and said lighter (25) being mutually arranged so that an electrical heater element of the lighter at least partially superposes the filled and unfilled tobacco rod portions when the cigarette is in an operative position in said lighter.

2. A cigarette for use in the system of claim 1, comprising a tobacco rod said tobacco rod (60) comprising a tubular tobacco web (66) and a plug of tobacco (80) disposed within said tubular tobacco web, said tobacco rod having a free end (78) and an opposite end (72), said tubular tobacco web comprising a base web (68) and a layer (70) of tobacco flavour material supported by said base web, said base web adapted to transfer heat from an electrical heating element (37) to said tobacco flavour material, said tobacco rod (60) adapted to operatively receive an electrical heating element (37) alongside said tobacco rod (60) at a location between said free end (78) and said opposite end (72), said plug of tobacco (80) located adjacent said free end, said plug of tobacco being spaced apart from said opposite end so as to define an unfilled space (91) between said plug of tobacco and said opposite end.

3. The cigarette as claimed in claim 2, wherein said location alongside said tobacco rod is such that said location overlaps at least a portion of said unfilled space (91) and overlaps at least a portion of said plug of tobacco (80).

4. The cigarette as claimed in claim 2 or3, wherein said tobacco rod includes a free-flow filter (74) adjacent said opposite end, said free-flow filter being spaced apart from said plug of tobacco (80) so as to define said unfilled space (91) between said free-flow filter and said plug of tobacco.

5. A cigarette, for use in the system of claim 1, wherein said filled tobacco rod portion includes a plug of tobacco, and said electrical heater superposes at least a portion of said unfilled space and superposes at least a portion of said plug of tobacco when the cigarette is in said operative position in the lighter.

6. The cigarette as claimed in claim 4, wherein said cigarette has a free end, said tobacco plug being located adjacent said free end, said cigarette including a tubular element spaced apart from said plug of tobacco so as to define said unfilled tobacco rod portion between said free-flow filter and said plug of tobacco.

7. The cigarette as claimed in claim 6, wherein said tubular element (74) is a filter.

8. The cigarette as claimed in claim 7, wherein said tubular element (74) is constructed from a plasticized tow material.

9. The cigarette as claimed in claim 7, wherein said free-flow filter (74) is constructed from a moulded material.

10. The cigarette as claimed in any one of claims 4 to 9, further comprising filter tipping (62) adjacent said opposite end.

11. The cigarette as claimed in claim 10, wherein said tipping (62) comprises a second free-flow filter (102) adjacent said opposite end, said cigarette further comprising tipping paper (64) attaching said second free-flow filter (102) to said opposite end.

12. The cigarette as claimed in claim 11, wherein said tipping further comprises a mouthpiece filter plug (104) adjacent said second free-flow filter (102).

13. The cigarette as claim in claim 12, wherein said free-flow filter (74) of said tobacco rod (66) includes a first passage (75) and said second free-flow filter (102) of said tipping includes a second passage, said first and second passages communicating said unfilled space (91) of said tobacco rod with said mouthpiece filter plug (104), said second passage having a second inside radius greater than a first inside radius of said first passage (75).

14. The cigarette as claimed in claim 12, wherein said tobacco rod further comprises a back flow filter (200") at said free end.

15. The cigarette as claimed in claim 12, wherein said plug of tobacco (80b) includes a first portion (320b) adjacent said free end (78b) which has a higher density than a second portion (310b) of said plug of tobacco distal from said free end.

16. A cigarette (23), for use in the system of claim 1, comprising a tobacco rod (60) having a back-flow resistive free end (78) and an opposite end (72), said tobacco rod comprising a tubular tobacco (66) web including a layer of tobacco material (70), a flow constriction (74) operatively at said opposite end of said tubular web and tobacco operatively situated adjacent said free end and space from said flow constriction, the tobacco comprising cut filler partially filling said tobacco rod so as to define a filled tobacco rod portion and an unfilled tobacco rod portion, said unfilled portion being located adjacent said flow constriction, said tubular web arranged to communicate heat received by said tubular web to said filler tobacco, said tobacco rod (60) being arranged such that during a puff on said cigarette with an application of heat along a region of said tubular web, at least a portion of the filler tobacco is caused to release tobacco aerosol which is drawn through said flow constriction.

17. The cigarette as claimed in claim 16, wherein said flow constriction (74) is defined by a tubular element.

18. The cigarette as claimed in claim 17, wherein said tubular element comprises a first free-flow filter (74), said first free-flow fitter defining a first passage (75) therethrough, said cigarette further comprising tipping (62), said tipping including a second tubular free-flow filter (102) locate adjacent said first free-flow filter of said tobacco rod, said second tubular free-flow filter defining a second passage therethrough, said first passage of said first free-flow filter being narrower than said unfilled portion (91) of said tobacco rod and narrower than said second passage of said second free-flow filter (102).

19. The cigarette as claimed in claim 18, wherein said cut filter tobacco forms a back-flow resistive plug.

20. The cigarette as claimed in claim 19, wherein said portion of said tobacco (80) is located at said free end (78) and has a density greater than a reminder of said cut filler tobacco distal from said free end.

21. The cigarette as claimed in claim 20, wherein said tipping (62) further comprises a mouthpiece filter (104) adjacent said second free-flow filter (102).

22. The cigarette as claimed in claim 20, wherein said tubular web includes a cigarette wrapper (71) about said tobacco rod (60), said tipping attached to said tobacco rod with a tipping paper (64).

23. The cigarette as claimed in any one of claims 2 to 22, wherein said tobacco or plug of tobacco (80) comprises a cut filler tobacco.

24. The cigarette as claimed in claim 23, wherein said tobacco or plug of tobacco (80) comprises a blend of cut filler tobacco, said blend comprising a combination of at last two of bright, burley and oriental tobaccos.

25. The cigarette as claimed in claim 23 or 24, wherein said plug of tobacco included a plug wrap (84) disposed about said cut filler tobacco (80).

26. The cigarette as claimed in claim 23 or 24, wherein said tobacco (70) is located along an inside surface of said tubular tobacco web (66).

27. The cigarette as claimed in claim 26, wherein said tobacco rod comprises an overwrap (71) disposed about an outside surface of said tubular tobacco rod or rod portion.

28. A tobacco web adapted to be rolled into the tubular tobacco rod (60) of a cigarette (23) operative with the electrical cigarette lighter (25) in the system of claim 1, said tobacco web comprising a base web (68) and a tobacco material, (70) disposed along a first side of said base web:
said base web comprising a combination of tobacco fibre and cellulosic fibre, said tobacco fibre and said cellulosic fibre combined at a ratio in the range of approximately 2:1 to 4:1, said base web having a base weight in a range of approximately 35 to 45 g/m2;

said tobacco material having at least twice the basis weight of said base web, said tobacco material comprising finely ground tobacco and extracted tobacco solids at a ratio in a range of approximately 3:1 to 9:1, and a humectant at a level of approximately 5% to 20% by weight of said material.

29. The tobacco web as claimed in claim 28, wherein said tobacco material has a basis weight of approximately three to four times that of said base web.

30. The tobacco web as claimed in claim 28 or 29, wherein said tobacco material further comprises pectin at a level of up to approximately 2% by weight of said tobacco material.

31. The tobacco web as claimed in claim 30, where said base web comprises approximately 28 g/m2 tobacco fibre and approximately 12 g/m2 cellulosic fibre of a wood pulp of flax pulp, or tobacco stem pulp.

32. The tobacco web as claimed in claim 31, wherein said tobacco material comprises approximately 66 to 71% by weight tobacco particles, approximately 16 to 20% by weight extracted tobacco solids, approximately 10 to 14% by weight glycerine and approximately 1-2%
pectin.

33. A tobacco web adapted to rolled into the tubular tobacco rod (60) of a cigarette (23) operative with the electrical cigarette lighter (25) for use in the system of claim 1, said tobacco web comprising a base web (68) and a tobacco material (70) disposed along a first side of said base web:
said base web comprising a combination of tobacco fibre at a component basis weight of approximately 20 to 30 g/m2 and carbon fibre at a component basis weight of approximately 2-9 g/m2, and pectin at a component basis weight of approximately 1 g/m2 said tobacco material having a basis weight three to four times that of said base web, said tobacco material comprising finely ground tobacco and extracted tobacco solids at a ratio in a range of approximately 3:1, to 9:1; and a humectant at a level in the range of approximately 5 % to 20% by weight of said tobacco material.

34. A cigarette comprising a tubular tobacco rod (6) constructed from a tobacco web according to any one of claims 29 to 34.

35. The cigarette as claimed in claim 34, further comprising a plug of cut fills (80) adjacent a free end (78) of said tobacco rod (60), at least one tubular free-flow filter (74) adjacent an opposite end (72) of said tobacco rod and a filler-free void (91) located between said plug of cut filler and said tubular free-flow filter.

36. The tobacco web as claimed in claim 33, wherein said tobacco fibre is at a component basis weight of approximately 24 to 28 g/m2, carbon fibre is at a component basis weight of approximately 2 to 4 g/m2 and pectin is at a component basis weight of 2.5 to 1.5 g/m2.

37. A heater (39) for use in the smoking system of claim 1, a source of electrical energy for heating a cigarette, the heater comprising:
a plurality of electrically resistive heater blades (121) defining a receptacle to receive an inserted cigarette and extending alongside the inserted cigarette, each blade comprising a first heater blade leg (116A) having a first end and a second and, a second heater blade leg (116B) having a first end and a second (122) end, and a connecting section (118) connecting the second end of said first heater blade leg and the first end of said second heater blade leg;
wherein said first and second heater blade legs of each heater blades are separated by a respective gap (125); and wherein the first ends of said first heater blade leg are adapted to be in electrical contact with the source of electrical energy, wherein respective resistive heating paths are formed comprising said first heater blade leg, said connecting section, and, said second heater blade leg to respectively heat each of said electrically resistive beater blades, which in turn heats the inserted cigarette, said first ends of said first heater blades having a common connection and wherein the second ends of said second heater blade legs are adapted to be in respective electrical contact with the source of electrical energy.

38. The heater according to claim 37, wherein the first ends (122) of said first heater blade legs (116A) are grounded.

39. The heater according to claim 37 or 38, wherein the common connection of the first ends of said first heater blade legs in a hub.

40. The heater according to any one of claims 37 to 39, wherein the gap (125) separating said first and second heater blade legs is sized to permit entrainment of air flow into the heated cigarette upon drawing by a smoker.

47. The heater according to any one of claims 37 to 40 further comprising a supported hub (111), the first ends of each of said first heater blade legs (116A) extending from said supporting hub;
wherein said supporting hub is adapted to be in electrical contact with the source of electrical energy to form a common for the first ends of said first heater blade legs.

42. The heater according to claim 41, wherein the second ends of said second heater blade legs (116B) are adapted to be in respective electrical contact with the source of electrical energy, wherein respective resistive heating circuits are formed comprising said first heater blade leg, said connecting edge section, and said second heater blade to respectively heat each of said electrically resistive heater blades (121), which in turn heats the inserted cigarette.

43. The heater according to claim 41 or 42, wherein the second ends (122) of said second heater blade legs (116B) extend toward said supporting hub (111) and are electrically insulated therefrom.

44. The heater according to claim 41 or 42, wherein the second ends (122) of said second heater blade legs (116B) are separated from said hub by a gap.

45. The heater according to claim 41, further comprising an electrical insulator applied to at least one of said hub and the second ends of said second heater blade legs.

46. The heater according to claim 41, further comprising an electrical insulator applied to at least one of the second ends of said second heater blade legs and the first ends of said first heater blade legs.

47. The heater according to claim 41, further comprising an electrical insulator (300) forming a ceramic hub support structure around said supporting hub (111), the second ends (122) of said second heater blade legs (116B) and the first ends of said first heater blade legs (116B).

48. The heater according to any one of claims 41 to 47, wherein said supporting hub and said blades are monolithic.

49. The heater according to any one of claims 37 to 48, wherein said connecting section (118) further comprises a free end (118B) to compensate for thermal expansion when the heater element is heated.

50. The heater according to claim 49, further comprising a support structure (83) stationarily located within the smoking system and defining channels (21) to receive the free ends (118B) of said connecting sections of said blades (121).

51. The heater according to claim 50, wherein said channels (210) are arranged to permit translational thermal expansion and contraction of said heater blades.

52. The heater according to claim 50 or 51, further comprising a pivot point (204) located in each of said channels, said pivot point located such that the associated free end (118B) of said connecting section pivots about said pivot points to bias said first and second heater blade legs (116A,B) inward toward the inserted cigarette upon heating of the associated heater blade.

53. The heater according to any one of claims 37 to 52, wherein portion of at least one of said first heater blade leg (116A) and said second heater blade leg (116B) are coated with a ceramic (300) to strengthen and electrically insulate the at least one of said first heater blade leg and said second heater blade leg.

54. The heater according to claim 53, wherein a portion of said second heater blade leg (116B) adjacent said ceramic is adapted to be in electrical contact with the source of electrical energy.

55. The heater according to any one of claims 37 to 54, wherein said blades (121) are arranged to slidingly receive the inserted cigarette.

56. The heater according to any one of claims 37 to 55, wherein the second end of said second heater blade leg is a step shape, said step shape comprising an end section (122C) adapted to be in electrical contact with the source of electrical energy.

57. The heater according to any one of claims 37 to 56, wherein said first and second heater blade legs (116A,B) of a respective heater blade (121) are substantially parallel.

58. The heater according to any one of claims 37 to 57, wherein said connecting edge has a curvature between approximately 160° and 200°.

59. The heater according to any one of claims 37 to 58, wherein an underside of at least one of said first and second heater blade legs (116A,B) facing the inserted cigarette is substantially non-planar in a transverse direction of said heater blade leg.

60. The heater according to claim 59, wherein said underside is curved.

61. The heater according to claim 59, wherein said underside is angled.

62. The heater according to any one of claims 37 to 61, wherein said plurality of electrically resistive heater blades (121) are arranged in groups, wherein gaps (133) between the groups are sized to provide unheated portions of the inserted cigarette providing strength to facilitate removal of the cigarette after smoking.

63. The heater according to any one of claims 37 to 62, wherein at least one of said first and second heater blade legs (116A,B) is serpentine shaped.

64. The heater according to claim 63, wherein both said first and second blade legs are serpentine and mutually parallel such that space between the legs is serpentiginous.

65. The heater according to claim 37, wherein at least one end of at least one blade (121,122) is wider than an adjacent active portion of said at least one leg, wherein the end of said leg has a lower current density and a lower ohmic heating than the active portion of said leg.

66. The heater according to any one of claims 37 to 65, wherein said connecting section (119) is perforated.

67. The heater according to any one of claims 37 to 66, wherein said first and second heater blade legs (116A,B) are biassed inwardly toward the inserted cigarette.

68. The heater according to any one of claims 37 to 67, wherein said first and said second heater blade legs (116A,B) and said connecting edges have a resistance of approximately 200 µohm.cm.

69. The heater according to any one of claims 37 to 68, wherein said first and said second heater blade legs (116A,B) and said connecting edges have a resistance of approximately 50 to approximately 500 µohm.cm.

70. The heater according to any one of claims 39 to 69, wherein said first and said second heater blade legs (116A,B) and said connecting edges are capable of reaching temperatures of approximately 200°C to approximately 1,000°C in approximately 0.2 to approximately 2.0 sec. with a pulse of approximately 10 to approximately 50 Joules.

71. The heater according to claim 70, wherein said first and second legs (116A,B) and said connecting edges are capable of being pulsed to these temperatures for approximately 1,800 to approximately 10,000 such pulses.

72. The heater according to claim 37, wherein the gap (125) separating said first and second heater blade legs (116A,B) is sized to maximise cumulative radiative heating from each of said first and second heater blade legs of an associated heater blade to a portion of the inserted cigarette underlying the gap.

73. The heater according to any one of claims 37 to 72, wherein said first and second heater blade legs (116A,B) and said connecting edge section comprise an electrically resistive material selected from the group consisting of iron aluminides and nickel aluminides.

74. An electrical smoking system comprising a cigarette (23) comprising a tobacco rod, said tobacco rod (60) comprising a tubular tobacco web (66) and a plug of tobacco (80) disposed within said tubular tobacco web, said tobacco rod having a free end (78) and an opposite end (72), said tubular tobacco web comprising a base web (68) and a layer (70) of tobacco flavour material supported by said base web, said base web adapted to transfer heat from an electrical heating element (37) to said tobacco flavour material, said tobacco rod (60) adapted to operatively receive an electrical heating element (37) alongside said tobacco rod (60) at a location between said free end (78) and said opposite end (72), said plug of tobacco (80) located adjacent to said free end, said plug of tobacco being spaced apart from said opposite end so as to define an unfilled space (91) between said plug of tobacco and said opposite end; and a lighter, the lighter having a plurality of resistive heater blades and defining a receptacle for receiving the heater blades, whereby the blades at least partially overlap said tobacco plug when said cigarette is inserted into said receptacle.

75. A cigarette for use in the electrical smoking system of claim 74 wherein said location along said tobacco rod is such that said location overlaps at least a portion of said unfilled space (91) and overlaps at least a portion of said plug of tobacco (80).

76. The cigarette as claimed in claim 75, wherein said tobacco rod includes a free-flow filter (74) adjacent said opposite end, said free-flow filter being spaced apart from said plug of tobacco (80) so as to define said unfilled space (91) between said free-flow filter and said plug of tobacco.

77. A cigarette for use in the electrical smoking system of claim 74 wherein said tobacco rod includes a free-flow filter (74) adjacent said opposite end, said free-flow filter being spaced apart from said plug of tobacco (80) so as to define said unfilled space (91) between said free-flow filter and said plug of tobacco.

78. An electrical smoking system according to claim 74, wherein said heater blades extend along the length of said tobacco plug and partially overlap said unfilled space.

79. An electrical smoking system according to claim 74, wherein the lighter includes a heater according to any one of claims 38 to 74.