Europliisches Patentamt
`
`European Patent Office
`
`Office europeen des brevets
`
`1111111111111111111111111111111111111111111111111111 111!111111111111111111
`
`(11)
`
`EP O 917 830 A1
`
`EUROPEAN PATENT APPLICATION
`
`(19)
`
`'
`
`(12)
`
`(43) Date of publication:
`26.05.1999 Bulletin 1999121
`
`(21) Application number: 98124696.0
`
`(22) Date of filing: 10.09.1993
`
`(84) Designated Contracting States:
`AT BECH DE DKES FRGB GRIE ITLI LUMC NL
`PTSE
`
`(30) Priority: 11.09.1992 US 943504
`
`(62) Document number(s) of the earlier application(s) in
`accordance with Art. 76 EPC:
`93921427.6 10 615 411
`
`(71) Applicant:
`Philip Morris Products Inc.
`Richmond Virginia 23234 (US)
`
`(72) Inventors:
`• Collins, Alfred L.
`Powhatan, A 23139 (US)
`• Counts, Mary Ellen
`Richmond, VA 23112 (US)
`• Das, Amitabh
`Midlothian, VA 23112 (US)
`• Deevi, Seetharama C.
`Midlothian, VA 23112 (US)
`• Fleischhauer, Grier
`Midlothian, VA 23113 (US)
`• Hajalogol, Mohammad R.
`Richmond, 23236 (US)
`• Hayes, Patrick H.
`Chester, VA 23831 (US)
`• Higgins, Charles T.
`Richmond, 23339 (US)
`• Houck, Willie G. Jnr.
`Richmond, 23835 (US)
`• Keen, Billy J. Jnr.
`Chesterfield, 23832 (US)
`• Laroy, Bernard C.
`Richmond, 23112 (US)
`• Lee, Robert E. Ill.
`Richmond, 23233 (US)
`• Lilly, Clifton A. Jnr.
`Chesterfield, 23832 (US)
`
`(51) Int. Cl.6 : A24F 47/00
`
`• Lipowicz, Peter J.
`Midlothian, 23112 (US)
`• Losee, Bruce D. Jnr.
`Richmond, 23221 (US)
`• McCafferty, Hugh J.
`Midlothian, 23112 (US)
`• Miser, Donald E.
`Midlothian, 23112 (US)
`• Nocholas, Constance H.
`Chesterfield, 23832 (US)
`• Raymond, Wynn R.
`Richmond, 23832 (US)
`• Ripley, Robert L.
`Richmond, 23235 (US)
`• Rit1, Renzer R.
`Richmond, 23235 (US)
`• Scott, Robert G.
`Midlothian, 23113 (US)
`• Sprinkel, Murphy F.
`Glen Allen, VA 23060 (US)
`• Stevens, William H.
`Midlothian, 23113 (US)
`• Subbiah, Mantharam
`Midlothian, 23113 (US)
`• Utsch, Francis V.
`Midlothian, 23113 (US)
`• Watkins, Michael L
`Chester, VA 23831 (US)
`• Wrenn, Susan E.
`Cester1ield, Virginia 23832 (US)
`
`(74) Representative:
`Lloyd, Patrick Alexander Desmond
`Reddie & Grose
`16 Theobalds Road
`London WC1 X 8PL (GB)
`
`Remarks:
`This application was filed on 24 - 12 - 1998 as a
`divisional application to the application mentioned
`under INID code 62.
`
`(54) Method and apparatus for manufacturing a heater assembly for use in an electric smoking
`system
`
`A heater assembly (89) for a smoking system is
`(57)
`formed by cutting a sheet of resistive material to form a
`
`sheet ( 115) of resistive material connected to one
`another at at least one end (117,121), and forming that
`
`PrinlerdbyXe,ox (UK) BusiiessS.rvices
`216.71'.l.6
`
`(Cont. next page)
`
`""" <(
`0
`M
`C0
`I'-
`""" m
`0
`
`C. w
`
`Ex. 2019-0001
`
`

`

`EP O 917 830 A1
`
`material into a cylindrical shape. The heater elements
`may be bowed inwards towards the centerline and to
`the tight. The edges of the heating elements may elec(cid:173)
`tropolished to smooth them and the sheet is formed into
`
`a cylindrical shape before cutting to form the heater ele(cid:173)
`ments.
`
`Fig. 7
`
`117
`
`129
`
`2
`
`Ex. 2019-0002
`
`

`

`EP O 917 830 A1
`
`2
`
`ufacturing an integrated heater assembly for use in a
`smoking system for delivering a flavored tobacco
`response to a smoker, comprising:
`
`cutting means for cutting a sheet of resistive mate(cid:173)
`rial to form a plurality of heater elements connected
`to one another at at least one end; and
`forming means for forming the sheet in to a cylindri(cid:173)
`cal shape.
`
`[0007] The invention further provides a lighter for use
`in combination with a removable cigarette in a smoking
`system that delivers a flavored tobacco response to a
`smoker, the lighter comprising:
`
`a heater fixture for receiving, through a first end, a
`removable cigarette,
`the heater fixture having
`means for providing a flow of air to at least a portion
`of the cigarette; and
`a plurality of electrical heater elements disposed in
`the heater fixture, each of the heater elements hav(cid:173)
`ing a surface for being disposed adjacent a surface
`of the portion of the cigarette to which the flow of air
`is provided; and
`means for individually activating the plurality of
`heating elements such that a predetermined quan(cid:173)
`tity of flavored tobacco response is generated in the
`cigarette,
`wherein, when a smoker draws on a ciga(cid:173)
`rette inserted in the lighter, air flows transversely
`into the cigarette. A system embodying the inven(cid:173)
`tion has the advantage that condensation of aero(cid:173)
`sol onto heating elements and other structural
`components of a lighter is minimized.
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`Description
`
`This invention relates to smoking systems in
`[0001]
`which cigarettes are used with lighters, and in particular
`to the manufacture of heaters for use in lighters.
`[0002] An electrical smoking article is described in our
`United States Patent No. 5,060,671, which is hereby
`incorporated by reference in its entirety. That patent
`described a smoking article which is provided with a dis(cid:173)
`posable set of electrical heating elements. A charge of
`tobacco flavor medium containing, for example, tobacco
`or tobacco-derived material is deposited on each of the
`heating elements. The disposable heater/flavor unit is
`mated to a source of electrical energy such as a battery
`or capacitor, as well as to control circuitry to actuate the
`heating elements in response to a puff by a smoker on
`the article or in response to the depression of a manual
`switch. The circuitry is designed so that at least one, but
`less than all of the heating elements are actuated for
`any one puff, and so that a predetermined number of
`puffs, each containing a pre-measured amount of
`tobacco flavor substance, eg, an aerosol containing
`tobacco flavors or a flavored tobacco response, is deliv(cid:173)
`ered to the smoker. The circuitry also preferable pre(cid:173)
`vents the actuation of any particular heater more than
`once, to prevent overheating of the tobacco flavor
`medium thereon.
`[0003] With such articles, the heater is thrown away
`with the spent remainder of tobacco material. Also, the
`electrical connections between the heaters and the bat-
`tery must be able to endure repeated release and
`reconnection as flavor units are replaced.
`In our copending, United states Patent Applica(cid:173)
`[0004]
`tion Serial No. 07/666,926, filed March 11, 1991, now
`abandoned in favor of Continuing Application Serial No.
`08/012,799, filed February 2, 1993, an electrical smok-
`ing article is disclosed that has reusable heating ele(cid:173)
`ments and a disposable portion for tobacco flavor
`generation. The disposable portion preferably includes
`a flavor segment and a filter segment, attached by a tip-
`ping paper or other fastening arrangement. Certain
`operational difficulties are, however, associated with
`reusable heating elements, particularly in that residual
`aerosol tends to settle the condense on the heating ele(cid:173)
`ments and other permanent structural components of
`the article. The present invention aims to provide
`improvements in lighter and heater elements.
`[0005] According to the invention, there is provided a
`method for manufacturing an integrated heater assem-
`bly for use in a smoking system for delivering a flavored
`tobacco response to a smoker, comprising the steps of:
`
`cutting a sheet of resistive material to form a plural(cid:173)
`ity of heater elements connected to one another at
`at least one end; and
`forming the sheet into a cylindrical shape.
`
`40
`
`45
`
`[0008] Embodiments of the invention may have the
`further advantage of providing improved aerosol and
`flavor delivery to the smoker.
`In accordance with a preferred embodiment of
`[0009]
`the invention, the lighter includes a heater fixture for
`receiving, through a first end, a removable cigarette.
`The heater fixture has means for providing a transverse
`flow of air to at least a portion of the cigarette. A plurality
`of electrical heater elements are disposed in the heater
`fixture. Each of the heater elements has a surface for
`being disposed adjacent a surface of the portion of the
`cigarette to which the traverse flow of air is provided.
`Means are provided for activating one or more of the
`plurality of electrical heating means such that a prede(cid:173)
`termined quantity of flavored tobacco response is gen(cid:173)
`erated in the cigarette. The transverse flow of air is
`generated when a smoker draws on a cigarette inserted
`in the lighter.
`Embodiments of the invention in its various
`[001 0]
`55 aspects will now be described, by way of example, and
`with reference to the accompanying drawings, in which:
`
`50
`
`[0006] The invention also provides apparatus for man-
`
`Figure 1 is a schematic perspective view of a smok-
`
`3
`
`Ex. 2019-0003
`
`

`

`3
`
`EP O 917 830 A1
`
`4
`
`ing system embodying the invention;
`
`view taken at section 128-128 of Figure 12A;
`
`Figure 2 is a partially broken, schematic perspec(cid:173)
`tive view of a smoking system embodying the
`invention;
`
`5
`
`Figure 3A is a side, cross-sectional view of a heater
`fixture of the system of figure 2.
`
`Figure 38 is an end view of taken at section 38-38
`of Figure 3A;
`
`10
`
`Figure 4A is a schematic perspective view of a cig(cid:173)
`arette for use with a lighter embodying the inven-
`tion;
`
`15
`
`Figure 12C is a schematic view taken at section
`12C-12C of Figure 12A;
`
`Figure 12D is a schematic view taken at section
`12D-12D of Figure 12A;
`
`Figure 13 is an end view of a ring;
`
`Figure 14A is a schematic, perspective view of a
`cap;
`
`Figure 148 is a schematic, side cross-sectional
`view taken at section 148-148 of Figure 12A;
`
`Figure 48 is a side cross-sectional view taken at
`section 48-48 of Figure 4A;
`
`Figure 14C is a schematic view taken at section
`14D-14D of Figure 14A;
`
`Figure 5 is a schematic assembly view of a heater 20
`fixture made according to the method of the inven(cid:173)
`tion;
`
`Figure 6 is a perspective view of a heater assembly
`made according to the method of the invention;
`
`25
`
`Figure 7 is an outline of a heater assembly made
`according to the method of the invention;
`
`Figure 8 is a perspective view of a portion of a
`heater made according to an embodiment of the
`invention;
`
`30
`
`Figure 9 is a perspective view of a pin assembly
`made according to an embodiment of the invention;
`
`35
`
`Figure 1 OA is a schematic, side cross-sectional
`view of a spacer embodying the invention;
`
`Figure 1 OB is a schematic view taken at section
`108-108 of Figure 10A;
`
`40
`
`Figure 14D is a schematic view taken at section
`14D-14D of Figure 14A;
`
`Figure 15A is a schematic side view of a heater
`sleeve;
`
`Figure 158 is an end view taken at section 158-158
`of Figure 15A;
`
`Figures 16 and 17 are schematic side cross-sec(cid:173)
`tional views of portions of a smoking system show(cid:173)
`ing air flow paths in the smoking system;
`
`Figure 18 is a schematic circuit diagram showing
`circuitry;
`
`Figure 19 is a schematic, cross-sectional side view
`of a further smoking system;
`
`Figure 20 is a schematic, cross-sectional side view
`of a further heater fixture;
`
`Figure 21
`is a schematic perspective view of an
`apparatus for manufacturing a centre portion of a
`disposable cigarette of the smoking system in Fig(cid:173)
`ure 19;
`
`45
`
`Figure 22 is a schematic, cross-sectional side view
`of a peripheral draw embodiment of a smoking sys(cid:173)
`tem;
`
`Figure 23 is a schematic circuit diagram showing
`further circuitry; and
`
`Figure 24 is a schematic circuit diagram of a timing
`network of the control circuit of Figure 23.
`
`Figure 1 OC is a schematic view taken at section
`1 OC-1 OC of Figure 1 OA;
`
`Figure 11 A is a schematic, side cross-sectional
`view of a base
`
`Figure 11 B is a schematic view taken at section
`118-11 B of Figure 11A;
`
`50
`
`Figure 11 C is a schematic view taken at section
`11 C-11 C of Figure 11 A;
`
`Figure 12A is a schematic, perspective view of a
`combined spacer base member;
`
`55
`
`Figure 128 is a schematic, side cross-sectional
`
`4
`
`Ex. 2019-0004
`
`

`

`5
`
`EP O 917 830 A1
`
`6
`
`Detailed Description
`
`5
`
`10
`
`15
`
`20
`
`30
`
`35
`
`40
`
`45
`
`ture 39 includes eight radially spaced heating elements
`43, seen in FIG. 3A, that are individually energized by
`the power source 37 under the control of the circuitry 41
`to heat eight areas around the periphery of the cigarette
`23
`to develop eight puffs of a flavored
`tobacco
`response. While other numbers of heating elements 43
`may be provided, eight heater elements are preferred,
`at least because there are nominally eight puffs on a
`conventional cigarette and because eight heater ele(cid:173)
`ments lend themselves to electrical control with binary
`devices.
`The circuitry 41 is preferably activated by a
`[0015]
`puff-actuated sensor 45, seen in FIG. 2, that is sensitive
`either to pressure changes or air flow changes that
`occur when a smoker draws on the cigarette 23. The
`puff-actuated sensor 45 is preferably disposed in the
`front 33 of the lighter 25 and communicates with a
`space inside the heater fixture 39 and near the cigarette
`23 through a passageway 4 7 extending through a
`spacer 49 and a base 50 of the heater fixture and, if
`desired, a puff sensor tube (not shown). A puff-actuated
`sensor 45 suitable for use in the smoking system 21 is
`described in U.S. Patent No. 5,060,671, the disclosure
`of which is incorporated by reference, and is in the form
`of a Model 163PC01 D35 silicon sensor, manufactured
`by the MicroSwitch division of Honeywell, Inc., Freeport,
`Ill., which activates an appropriate one of the heater ele(cid:173)
`ments 43 as a result of a change in pressure when a
`smoker draws on the cigarette 23. Flow sensing
`devices, such as those using hot-wire anemometry prin(cid:173)
`ciples, have also been successfully demonstrated to be
`useful for activating an appropriate one of the heater
`elements 43 upon detection of a change in air flow.
`[0016] An indicator 51 is preferably provided on the
`exterior of the lighter 25, preferably on the front 33, to
`indicate the number of puffs remaining on a cigarette 23
`inserted in the lighter. The indicator 51 preferably
`includes a seven-segment liquid crystal display. In the
`presently preferred embodiment, the indicator 51 dis(cid:173)
`plays the digit "8" when a light beam emitted by a light
`sensor 53, seen in FIG. 2, is reflected off of the front of
`a newly inserted cigarette 23 and detected by the light
`sensor. The light sensor 53 is preferably mounted in an
`opening 55 in the spacer 49 and the base 50 of the
`heater fixture 39, seen, for example, in FIG. 3A. The
`light sensor 53 provides a signal to the circuitry 41
`which, in turn, provides a signal to the indicator 51. The
`display of the digit "8" on the indicator 51 reflects that
`the preferred eight puffs provided on each cigarette 23
`50 are available, i.e., none of the heater elements 43 have
`been activated to heat the new cigarette. After the ciga(cid:173)
`rette 23 is fully smoked, the indicator displays the digit
`"0". When the cigarette 23 is removed from the lighter
`25, the light sensor 53 does not detect the presence of
`a cigarette 23 and the indicator 51 is turned off. The light
`sensor 53 is modulated so that it does not constantly
`emit a light beam and provide an unnecessary drain on
`the power source 37. A presently preferred light sensor
`
`[0011] A smoking system 21 is seen with reference to
`Figures 1 and 2. The smoking system 21 includes a cig(cid:173)
`arette 23 and a reusable lighter 25. The cigarette 23 is
`adapted to be inserted in and removed from an orifice
`27 at a front end 29 of the lighter 25. The smoking sys(cid:173)
`tem 21 is used in much the same fashion as a conven(cid:173)
`tional cigarette. The cigarette 23 is disposed of after one
`or more puff cycles. The lighter 25 is preferably dis-
`posed of after a greater number of puff cycles than the
`cigarette 23.
`[0012] The lighter 25 includes a housing 31 and has
`front and rear portions 33 and 35. A power source 37 for
`supplying energy to heating elements for heating the
`cigarette 23 is preferably disposed in the rear portion 35
`of the lighter 25. The rear portion 35 is preferably
`adapted to be easily opened and closed, such as with
`screws or with snap-fit components, to facilitate replace(cid:173)
`ment of the power source 37. The front portion 33 pref-
`erably houses heating elements and circuitry in
`electrical communication with the power source 37 in
`the rear portion 35. The front portion 33 is preferably
`easily joined to the rear portion 35, such as with a dove-
`tail joint or by a socket fit. The housing 31 is preferably 25
`made from a hard, heat-resistant material. Preferred
`materials include metal-based or, more preferably, poly(cid:173)
`mer-based materials. The housing 31
`is preferably
`adapted to fit comfortably in the hand of a smoker and,
`in a presently preferred embodiment, has overall dimen-
`sions of 10.7 cm by 3.8 cm by 1.5 cm.
`[0013] The power source 37 is sized to provide suffi(cid:173)
`cient power for heating elements that heat the cigarette
`23. The power source 37 is preferably replaceable and
`rechargeable and may include devices such as a capac-
`itor or, more preferably, a battery. In a presently pre(cid:173)
`ferred embodiment, the power source is a replaceable,
`rechargeable battery (actually four nickel cadmium bat-
`tery cells connected in series) with a total, non-loaded
`voltage of approximately 4.8 to 5.6 volts. The character-
`istics required of the power source 37 are, however,
`selected in view of the characteristics of other compo(cid:173)
`nents in the smoking system 21, particularly the charac(cid:173)
`teristics of the heating elements. U.S. Patent No.
`5,144,962 describes several forms of power sources
`useful in connection with the smoking system of the
`present invention, such as rechargeable battery power
`sources and quick-discharging capacitor power sources
`that are charged by batteries, and is hereby incorpo(cid:173)
`rated by reference.
`[0014] A substantially cylindrical heating fixture 39 for
`heating the cigarette 23, and, preferably, for holding the
`cigarette in place relative to the lighter 25, and electrical
`control circuitry 41
`for delivering a predetermined
`amount of energy from the power source 37 to heating
`elements (not seen in FIGS. 1 and 2) of the heating fix-
`ture are preferably disposed in the front 33 of the lighter.
`In the presently preferred embodiment, the heating fix-
`
`55
`
`5
`
`Ex. 2019-0005
`
`

`

`7
`
`EP O 917 830 A1
`
`8
`
`53 suitable for use with the smoking system 21 is a Type
`OPR5005 Light Sensor, manufactured by OPTEK Tech(cid:173)
`nology, Inc., 1215 West Crosby Road, Carrollton, Texas
`75006.
`[0017] As one of several possible alternatives to using
`the above-noted light sensor 53, a mechanical switch
`(not shown) may be provided to detect the presence or
`absence of a cigarette 23 and a reset button (not
`shown) may be provided for resetting the circuitry 41
`when a new cigarette is inserted in the lighter 25, e.g.,
`to cause the indicator 51 to display the digit "8", etc.
`Power sources, circuitry, puff-actuated sensors, and
`indicators useful with the smoking system 21 of the
`present invention are described in U.S. Patent No.
`5,060,671, which is incorporated by reference. The pas-
`sageway 47 and the opening 55 in the spacer 49 and
`the heater fixture base 50 are preferably air-tight during
`smoking.
`[0018] A presently preferred cigarette 23 for use with
`the smoking system 21 is seen in detail in FIGS. 4A and
`4B, although the cigarette may be in any desired form
`capable of generating a flavored tobacco response for
`delivery to a smoker when the cigarette is heated by the
`heating elements 43. The cigarette 23 includes a
`tobacco web 57 formed of a carrier or plenum 59 which
`supports tobacco flavor material 61, preferably including
`tobacco. The tobacco web 57 is wrapped around and
`supported by a cylindrical back-flow filter 63 at one end
`and a cylindrical first free-flow filter 65 at an opposite
`end. The first free-flow filter 65 is preferably an "open-
`tube" type filter having a longitudinal passage 67
`extending through the center of the first free-flow filter
`and, hence, provides a low resistance to draw or free
`flow.
`If desired, cigarette overwrap paper 69 is
`[0019]
`wrapped around the tobacco web 57. Types of paper
`useful as the overwrap paper 69 include a low basis
`weight paper, preferably a paper with a tobacco flavor
`coating, or a tobacco-based paper to enhance the
`tobacco flavor of the flavored-tobacco response. A con-
`centrated extract liquor in full or-diluted strength may be
`coated on the overwrap paper 69. The overwrap paper
`69 preferably possesses a minimal base weight and cal-
`iper while providing sufficient tensile strength for
`machine processes. Presently preferred characteristics
`of a tobacco-based paper include a basis weight (at
`60% relative humidity) of between 20-25 grams/m2,
`minimum permeability of 0-25 CORESTA (defined as
`the amount of air, measured in cubic centimeters, that
`passes through one square centimeter of material, e.g.,
`a paper sheet, in one minute at a pressure drop of 1.0
`kilopascal), tensile strength ~ 2000 grams/27 mm width
`(1 in/min), caliper 1.3 - 1.5 mils, CaCO3 content ~ 5%,
`citrate 0%. Materials for forming the overwrap paper 69
`preferably include ~ 75% tobacco-based sheet (non-
`cigar, flue- or flue-lair-cured, mix filler and bright stem).
`Flax fiber in amounts no greater than that necessary to
`obtain adequate tensile strength may be added. The
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`6
`
`overwrap paper 69 can also be conventional flax fiber
`paper of basis weight 15-20 g/m2 or such paper with an
`extract coating. Binder in the form of citrus pectin may
`be added in amounts less than or equal to 1 %. Glycerin
`in amounts no greater than necessary to obtain paper
`stiffness similar to that of conventional cigarette paper
`may be added.
`The cigarette 23 also preferably includes a
`[0020]
`cylindrical mouthpiece filter 71, which is preferably a
`conventional RTD-type (Resistance To Draw) filter, and
`a cylindrical second free-flow filter 73. The mouthpiece
`filter 71 and the second free-flow filter are secured to
`one another by tipping paper 75. The tipping paper 75
`extends past an end of the second free-flow filter 73 and
`is attached to the overwrap paper 69 to secure an end
`of the first free-flow filter 65 in position adjacent an end
`of the second free-flow filter. Like the first free-flow filter
`65, the second free-flow filter 73 is preferably formed
`with a longitudinal passage 77 extending through its
`center. The back-flow filter 63 and the first free-flow filter
`65 define, with the tobacco web 57, a cavity 79 within
`the cigarette 23.
`It is preferred that the inside diameter of the
`[0021]
`longitudinal passage 77 of the second free-flow filter 73
`be larger than the inside diameter of the longitudinal
`passage 67 of the first free-flow filter 65. Presently pre(cid:173)
`ferred inside diameters for the longitudinal passage 67
`are between 1-4 mm and for the longitudinal passage
`77 are between 2-6 mm. It has been observed that the
`different inside diameters of the passages 67 and 77
`facilitates development of a desirable mixing or turbu(cid:173)
`lence between the aerosol developed from the heated
`tobacco flavor material and air drawn in from outside the
`cigarette 23 during drawing on the cigarette, resulting in
`an improved flavored tobacco response and facilitating
`exposure of more of an end of the mouthpiece filter 71
`to the mixed aerosol. The flavored tobacco response
`developed by heating the tobacco flavor material 61 is
`understood to be primarily in a vapor phase in the cavity
`79 and to turn into a visible aerosol upon mixing in the
`passage 77. In addition to the above-described first
`free-flow filter 65 having a longitudinal passage 67,
`other arrangements capable of generating the desired
`mixing of the vapor phase flavored tobacco response
`with introduced air include those in which a first free(cid:173)
`flow filter is provided in the form of a filter having a mul(cid:173)
`titude of small orifices, i.e., the first free-flow filter may
`be in the form of a honeycomb or a metal plate having
`multiple holes formed therein.
`[0022] Air is preferably drawn into the cigarette 23 pre(cid:173)
`dominantly through the tobacco web 57 and the over(cid:173)
`wrap paper 69, in a transverse or radial path, and not
`through the back-flow filter 63 in a longitudinal path. As
`explained below, however, it is desirable to permit air
`flow through the back-flow filter during a first puff on the
`cigarette to lower the RTD. It is presently understood
`that drawing air into the cigarette 23 longitudinally tends
`to result in the aerosol developed by heating the
`
`Ex. 2019-0006
`
`

`

`9
`
`EP O 917 830 A1
`
`10
`
`tobacco web 57 with the heater elements 43 arranged
`radially around the tobacco-web not being properly
`removed from the cavity 79. It is presently preferred to
`produce a flavored tobacco response as a function
`almost entirely of the makeup of the tobacco web 57
`and the energy level of the heater elements 43. Accord(cid:173)
`ingly, the portion of the air flow through the cigarette
`resulting from longitudinal flow through the back-flow fil-
`ter 63 is preferably minimal during smoking, except dur-
`ing the first puff. Further, the back-flow filter 63
`preferably minimizes the flow of aerosol in a backward
`direction out of the cavity 79 after heating of the tobacco
`flavor material 61, so that the potential for damage to
`components of the lighter 25 from aerosol flowing back(cid:173)
`ward from the cigarette 23 is minimized.
`[0023] The carrier or plenum 59 which supports the
`tobacco flavor material 61 provides a separation
`between the heating elements 43 and the flavor mate-
`rial, transfers heat generated by the heater elements to
`the flavor material, and maintains cohesion of the ciga-
`rette after smoking. Preferred carriers 59 include those
`composed of a non-woven carbon fiber mat, preferred
`because of its thermal stability. Such carriers are dis(cid:173)
`cussed
`in greater detail in copending commonly(cid:173)
`assigned United States Patent Application Serial No.
`07/943,747, filed September 11, 1992, which is incorpo(cid:173)
`rated by reference. Such mats should preferably have a
`thickness between about 0.05 mm and about 0.11 mm
`and be composed of nonwoven carbon fibers (having a
`basis weight in the range of from about 6 g/m2 to about
`12 g/m2 with fiber diameters between about 7 µm and
`about 30 µm). The lengths of the fibers should allow the
`mat to withstand the tensile stresses encountered dur-
`ing processing. Preferably, the mats should include a
`binder which is suitable for use in electric smoking arti(cid:173)
`cles (i.e., having acceptable subjective properties).
`[0024] Other carriers 59 include low mass, open mesh
`metallic screens or perforated metallic foils. For exam-
`ple, a screen having a mass in the range from about 5
`g/m2 to about 15 g/m2 and having wire diameters in the
`range from about 0.038 mm (about 1.5 mils) to about
`0.076 mm (about 3.0 mils) is used. Another embodi(cid:173)
`ment of the screen is formed of a 0.0064 mm (about
`0.25 mil)-thick foil (e.g., aluminum) having perforations
`with diameters in the range from about 0.3 mm to about
`0.5 mm, to reduce the mass of the foil by about 30 per(cid:173)
`cent to about 50 percent, respectively. Preferably, the
`perforation pattern of such a foil is staggered or discon(cid:173)
`tinuous (i.e., not in straight arrangement) to reduce the
`lateral conduction of heat away from the tobacco flavor
`material 61.
`Such metallic screens and foils are incorpo(cid:173)
`[0025]
`rated into a cigarette 23 in a variety of ways including,
`for example, (1) casting a tobacco flavor slurry on a belt
`and overlaying the screen or foil carrier on the wet slurry
`prior to drying, and (2) laminating the screen or foil car-
`rier to a tobacco flavor base sheet or mat with a suitable
`adhesive. Because of the possibility of electrical short-
`
`5
`
`10
`
`20
`
`25
`
`ing in or between the heater elements 43 where a
`metallic carrier is used, such carriers should generally
`not be in direct contact with the heating elements.
`Where a metallic carrier is used, suitable binders and
`low basis weight paper, such as the overwrap paper 69,
`are preferably used to provide electrical insulation
`between the metallic carrier 59 and the electrical heater
`elements 43.
`[0026] A presently preferred tobacco web 57 is formed
`using a paper making-type process. In this process,
`tobacco strip is washed with water. The solubles are
`used in a later coating step. The remaining (extracted)
`tobacco fiber is used in the construction of a base mat.
`Carbon fibers are dispersed in water and sodium algi-
`15 nate is added. Any other hydrocolloid which does not
`interfere with the flavored tobacco response, is water
`soluble, and has a suitable molecular weight to impart
`strength to the tobacco web 57 may be added in lieu of
`sodium alginate. The dispersion is mixed with the slurry
`of extracted tobacco fibers and optional flavors. The
`resultant mixture is wet-laid onto a fourdriner wire and
`the web is passed along the remainder of a traditional
`paper making machine to form a base web. The solu(cid:173)
`bles removed by washing the tobacco strip are coated
`onto one side of the base web, preferably by a standard
`reverse roll coater located after a drum or Yankee dryer.
`The tobacco solubles/tobacco dust or particulate ratio is
`preferably varied between a 1 :1 and a 20:1 ratio. The
`slurry may also be cast or extruded onto the base mat.
`30 Alternatively, the coating step is produced off-line. Dur(cid:173)
`ing or after the coating step, flavors that are conven(cid:173)
`tional in the cigarette industry are added. Pectin or
`another hydrocolloid is added, preferably in a range of
`between 0.1 to 2.0%, to improve the coatability of the
`35 slurry.
`[0027] Whichever type of carrier 59 is used, tobacco
`flavor material 61 which is disposed on the inner surface
`of the carrier liberates flavors when heated and is able
`to adhere to the surface of the carrier. Such materials
`include continuous sheets, foams, gels, dried slurries,
`or dried spray-deposited slurries, which preferably,
`although not necessarily, contain tobacco or tobacco(cid:173)
`derived materials, and which are more fully discussed in
`the above-incorporated United States Patent Applica(cid:173)
`tion Serial No. 07/943,747.
`[0028] Preferably, a humectant, such as glycerin or
`propylene glycol, is added to the tobacco web 57 during
`processing in amounts equalling between 0.5% and
`10% of humectant by the weight of the web. The
`humectant facilitates formation of a visible aerosol by
`acting as an aerosol precursor. When a smoker exhales
`an aerosol containing the flavored tobacco response
`and the humectant, the humectant condenses in the
`atmosphere, and the condensed humectant provides
`the appearance of conventional cigarette smoke.
`[0029] Because the tobacco flavor material 61 of the
`present invention is disposed on the surface of the car(cid:173)
`rier 59, its flavor delivery properties can be spatially var-
`
`40
`
`45
`
`50
`
`55
`
`7
`
`Ex. 2019-0007
`
`

`

`11
`
`EP O 917 830 A1
`
`12
`
`ied to allow the flavor delivery profile from puff to puff to
`be selectively varied. For example, the tobacco flavor
`material 61 adjacent a first heater element 43 can con-
`tain a first amount or type of flavorant whereas the
`tobacco flavor material adjacent a second heater ele-
`ment can contain a second different amount or type of
`flavorant. Thus, the flavored tobacco response delivery
`to a smoker can be selectively varied or tailored by
`employing non-uniform tobacco flavor material profiles
`disposed on the surface of the carrier material. The
`smoker might, for example, orient the disposable ciga(cid:173)
`rette 23 relative to the permanent heater elements in a
`particular manner when the cigarette is inserted into the
`lighter 25, if it is desired that a particular heater heat a
`predetermined portion of the non-uniform tobacco flavor
`material.
`Additionally, the flavored tobacco response
`[0030]
`may be selectively varied in accordance with the inven(cid:173)
`tion by providing a controlled amount of energy to the
`heater elements 43. For example, it the amount of
`energy delivered to the first heater element 43 (e.g., 20
`Joules) is greater than the amount delivered to the sec(cid:173)
`ond (e.g., 15 Joules),