United States Patent [19]
`Collins et al.
`
`[54] HEATER ELEMENT OF AN ELECTRICAL
`SMOKING ARTICLE AND METHOD FOR
`MAKING SAME
`
`[75]
`
`Inventors: Allred L. Collins, Powhatan; Mary E.
`Counts, Richmond; Amitabh Das;
`Seetharama C. Deevi, both of
`Midlothian; A. Clifton Lilly, Jr.,
`Chesterfield; D. Bruce Losee, Jr.,
`Richmond; Michael L Watkins,
`Chester; Francis V. Utsch, Midlothian,
`all of Va.
`
`[73] Assignee: Philip Morris Incorporated, New
`York, N.Y.
`
`[21] Appl. No.: 449,4(,2
`May 24, 1995
`
`[22] Filed:
`
`Related U.S. Application Data
`
`[60] Division of Ser. No. 943,504, Sep. 11, 1992, Pat. No.
`5,505,214, and a continuation-in-part of Ser. No. 666,926,
`Mar. 11, 1991, abandoned, and a continuation of Ser. No.
`12,799, Feb. 2, 1993, Pat. No. 5,249,586.
`[51] Int. Cl.6 ........... _______ A24F 47/00
`[52] U.S. CL ......... ___ 131/194; 131/329; 131/273
`[58] Field ofSearcli ______ 131/194, 329,
`131/359, 270-273; 128/202.21, 203.17,
`203.27
`
`[56}
`
`References Cited
`
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`
`111(cid:127)
`
`111111(cid:127)
`
`US005730158A
`[111 Patent Number:
`[451 Date of Patent:
`
`111111111111
`5,730,158
`Mar. 24, 1998
`
`3,591,753
`3,608,560
`3,738,374
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`
`7/1971 Gartner.
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`
`(List continued on next page.)
`
`FOREIGN PATENT DOCUMENTS
`
`1202378
`87/104459
`0 295 122
`0 358 002
`0 358114
`0 430566A2
`0 438 862 A2
`3 640 917
`3 735 704
`61-68061
`2 132 539
`2 148 079
`2 148 676
`WO 86/02528
`WO 95/05094
`
`3/1986
`2/1988
`12/1988
`3/1990
`3/1990
`6/1991
`7/1991
`8/1988
`5/1989
`4/1986
`7/1984
`5/1985
`5/1985
`5/1986
`2/1995
`
`Canada.
`China.
`European Pat. Off ..
`European Pat. Off ..
`European Pat. Off ..
`European Pat. Off ..
`European Pat. Off ..
`Germany.
`Germany.
`Japan.
`United Kingdom .
`United Kingdom .
`United Kingdom .
`WIPO.
`WIPO.
`
`Primary Examiner-Vincent Millin
`Assistant Examiner-William J. Deane, Jr.
`Attorney, Agent, or Finn-Charles E. B. Glenn; James E.
`Schardt; James T. Moore
`
`[57]
`
`ABSTRACT
`
`A smoking article is provided in which a replaceable tobacco
`:flavor unit containing tobacco flavor material is electrically
`heated by a set of permanent reusable heaters to evolve
`flavors or other components in vapor or aerosol form for
`delivery to a smoker. Each heater heats only a portion of the
`available tobacco flavor material so that a plurality of
`individual puffs of tobacco flavor substance can be delivered
`sequentially to the smoker. The replaceable tobacco flavor
`unit can also include a filter to reduce the effect of residual
`aerosol which settles or condenses on the permanent por(cid:173)
`tions of the article and which can result in off-tastes when
`reheated. A method and apparatus for manufacturing the
`replaceable tobacco :flavor unit is also provided.
`
`12 Claims, 12 Drawing Sheets
`
`44
`
`20
`
`31 ' 12
`
`54----'
`41
`47
`:40 23
`
`43
`
`34
`
`21
`f
`
`37
`
`-----T
`53
`~==f===~~~~~::::=:::=:=IJ_
`
`7 40
`
`Ex. 2004-0001
`
`

`

`U.S. PATENT DOCUMENTS
`
`6/1975 Guarnieri .
`3,889,690
`4/1977 Wasa et al ..
`4,016,061
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`4,131,119 12/1978 Blasutti .
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`4,215,708
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`3/1981 Carter et al ..
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`3/1981 Ohkubo.
`4,259,564
`4/1981 Green, Jr ..
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`4,303,083 12/1981 Burruss, Jr ..
`3/1982 Keith et al . .
`4,319,591
`7/1983 Jacobs.
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`4,431,903
`3/1984 Green, Jr ..
`4,436,100
`7/1984 Lawrence et al ..
`4,463,247
`3/1985 Cogbill et al. .
`4,505,282
`4,562,337 12/1985 Lawrence.
`2/1986 Herron.
`4,570,646
`4/1986 Green, Jr ..
`4,580,583
`4,621,649 11/1986 Osterrath.
`4,623,401 11/1986 Derbyshire et al ..
`4,629,604 12/1986 Spector.
`1/1987 Bonanno et al ..
`4,637,407
`4/1987 Derbyshire .
`4,659,912
`7/1987 Drapeau et al ..
`4,682,010
`8/1987 Spector.
`4,686,353
`9/1987 Spector.
`4,692,590
`9/1987 Ruderian.
`4,694,824
`4/1988 Gerth et al ..
`4,735,217
`
`5,730,158
`Page 2
`
`9/1988 Myer.
`4,771,796
`4,776,353 10/1988 Lilja et al ..
`6/1989 Luthy.
`4,837,421
`7/1989 Rose.
`4,846,199
`7/1989 Lilja et al ..
`4,848,376
`4,874,924 10/1989 Yamamoto et al ..
`4,877,989 10/1989 Drews et al ..
`5/1990 Brooks et al ..
`4,922,901
`8/1990 Gori.
`4,945,931
`8/1990 Brooks et al ..
`4,947,874
`8/1990 Brooks et al ..
`4,947,875
`4,966,171 10/1990 Seranno et al ..
`1/1991 Nichols et al. .
`4,981,522
`2/1991 Seranno et al ..
`4,991,606
`3/1991 Perfetti et al ..
`4,998,541
`5/1991 McMurtrie.
`5,016,656
`8/1991 Schleich et al ..
`5,040,552
`8/1991 Curtiss et al ..
`5,042,510
`5,060,671 10/1991 Counts et al. . ..................... 131/273 X
`5,076,296 12/1991 Nystrom et al . .
`3/1992 Deevi.
`5,093,894
`3/1992 Losee et al ......................... 131/270 X
`5,095,921
`9/1992 Counts et al. .
`5,144,962
`5,159,940 11/1992 Hayward et al ..
`1/1993 Losee et al. . .................. 128/202.21 X
`5,179,966
`2/1993 Hajaligol et al ..
`5,188,130
`7/1993 Deevi et al.
`5,224,498
`8/1993 Blackbum.
`5,235,157
`5,249,586 10/1993 Morgan et al. . .................... 131/270 X
`5,261,424 11/1993 Sprinkel .............................. 131/271 X
`5,269,327 12/1993 Counts et al. .. .................... 131/273 X
`5,274,214 12/1993 Blackbum.
`2/1994 Blackbum.
`5,285,050
`6/1994 Deevi et al ............................. 131/194
`5,322,075
`131/194
`5,353,813 10/1994 Deevi et al ........
`2/1995 Counts et al. .
`5,388,594
`1/1996 Counts et al ..
`5,479,948
`
`. 131/329 X
`
`Ex. 2004-0002
`
`

`

`U.S. Patent
`US. Patent
`
`Mar. 24, 1998
`Mar. 24, 1998
`
`Sheet 1 of 12
`Sheet 1 of 12
`
`5,730,158
`5,730,158
`
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`Ex. 2004-0003
`
`Ex. 2004-0003
`
`

`

`U.S. Patent
`US. Patent
`
`Mar. 24, 1998
`Mar. 24, 1998
`
`Sheet 2 of 12
`Sheet 2 of 12
`
`5,730,158
`5,730,158
`
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`
`Ex. 2004-0004
`
`Ex. 2004-0004
`
`

`

`U.S. Patent
`US. Patent
`
`Mar. 24, 1998
`Mar. 24, 1998
`
`Sheet 3 of 12
`Sheet 3 of 12
`
`5,730,158
`5,730,158
`
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`
`Mar. 24, 1998
`
`Sheet 4 of 12
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`Ex. 2004-0006
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`

`

`U.S. Patent
`US. Patent
`
`Mar. 24, 1998
`Mar. 24, 1998
`
`Sheet 5 of 12
`Sheet 5 0f 12
`
`5,730,158
`5,730,158
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`
`Ex. 2004-0007
`
`

`

`U.S. Patent
`
`Mar. 24, 1998
`
`Sheet 6 of 12
`
`5,730,158
`
`128
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`Ex. 2004-0008
`
`

`

`U.S. Patent
`
`Mar. 24, 1998
`
`Sheet 7 of 12
`
`5,730,158
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`Ex. 2004-0009
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`

`

`U.S. Patent
`US. Patent
`
`Mar. 24, 1998
`Mar. 24, 1993
`
`Sheet 8 of 12
`Sheet 8 of 12
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`

`

`U.S. Patent
`
`Mar. 24, 1998
`
`Sheet 9 of 12
`
`5,730,158
`
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`Ex. 2004-0011
`
`

`

`U.S. Patent
`US. Patent
`
`Mar. 24, 1998
`Mar. 24, 1998
`
`Sheet 10 of 12
`Sheet 10 of 12
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`26
`
`INDICATOR-----
`
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`ACTUATOR
`
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`8 !NETWORK
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`
`

`

`U.S. Patent
`
`Mar. 24, 1998
`
`Sheet 12 of 12
`
`5,730,158
`
`191A
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`Ex. 2004-0014
`
`

`

`5,730,158
`
`1
`HEATER ELEMENT OF AN ELECTRICAL
`SMOKING ARTICLE AND METHOD FOR
`MAKING SAME
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`Titls application is a divisional of U.S. application Ser.
`No. 07/943,504, filed Sep. lL 1992, now U.S. Pat. No.
`3,505,214, is a continuation-in-part of commonly-assigned
`U.S. patent application Ser. No. 07/666,926, filed Mar. 11,
`1991, now abandoned in favor of filewrapper continuation
`application Ser. No. 08/012,799, filed Feb. 2, 1993, now
`U.S. Pat. No. 5.249,586, which is hereby incorporated by
`reference in its entirety.
`
`BACKGROUND OF THE INVENTION
`Titls invention relates to smoking articles in which
`tobacco flavor media are heated to release tobacco flavors.
`More particularly, this invention relates to electrically
`heated smoking articles.
`An electrically-heated smoking article is described in
`commonly-assigned U.S. Pat. No. 5,060,671. which is
`hereby incorporated by reference in its entirety. That patent
`describes an electrically-heated smoking article which is
`provided with a disposable set of electrical heating elements
`on each of which is deposited an individual charge of
`tobacco flavor medium containing, for example, tobacco or
`tobacco-derived material. The disposable heater/flavor unit
`is mated to a more or less permanent unit containing a source 30
`of electrical energy such as a battery or capacitor, as well as
`control circuitry to actuate the heating elements in response
`to a puff by a smoker on the article or 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 35
`one puff, so that a predetermined number of puffs, each
`containing a pre-measured amount of tobacco flavor
`substance, is delivered to the smoker. The circuitry also
`preferably prevents the actuation of any particular heater
`more than once, to prevent overheating of the tobacco flavor 40
`medium thereon and/or the production of off tastes.
`In such an article, the heating elements are disposed of
`along with the spent flavor generating medium. This results
`in increased costs to the smoker, who must buy new heating
`elements with each refill of tobacco flavor medium. The
`volume of material disposed of is also greater when the
`heating elements must be disposed of.
`In addition, when the heating elements are disposable,
`they must by their nature be removable. As a result, there is
`sometimes excessive contact resistance at the connection
`where the removable heaters are electrically connected to
`the source of electrical energy, resulting in increased power
`consumption. Furthermore, that connection must be
`designed to withstand repeated insertion of new heating
`elements after each use.
`Also, when the heating elements are disposable, the heater
`electrical resistance may vary from heater to heater, result(cid:173)
`ing in variations in power consumption which, in turn, can
`lead to variations in temperature. As it is the temperature to
`which the tobacco flavor medium is heated that determines
`the characteristics of the flavor tobacco substance, those
`characteristics will also vary.
`The above-discussed disadvantages associated with U.S.
`Pat. No. 5,060,671 are addressed by above-incorporated
`copending, commonly-assigned U.S. patent application Ser.
`No. 08/012,799, filed Feb. 2, 1993. That application
`
`2
`describes an electrically-heated smoking article that has
`reusable heating elements and a disposable portion for
`tobacco flavor generation. The disposable portion preferably
`includes a tobacco flavor segment and a filter segment,
`5 attached by a plug wrap or other fastening means.
`A disadvantage of reusable heating elements is that
`residual aerosol can settle and condense on the heating
`elements and other permanent structural components of the
`article, resulting in the generation of off-tastes if the residual
`10 aerosol is reheated after new disposable tobacco flavor
`medium is inserted into the article. Such residue is referred
`to as ''fixture contamination."
`In light of the above, it would therefore be desirable to be
`able to provide an electrically-heated smoking article in
`15 which the heating elements are reusable, and of which the
`volume of disposable portions is thus minimized.
`It would also be desirable to be able to provide such an
`article in which generation of off-tastes resulting from the
`20 reheating of aerosol that settles or condenses onto the
`heating elements and other permanent structural compo(cid:173)
`nents of the article is minimized.
`It would further be desirable to be able to provide manu(cid:173)
`facturing processes for such an article that can be irnple-
`25 mented using conventional high-volume assembly machin(cid:173)
`ery.
`
`45
`
`SUMMARY OF THE INVENTION
`It is an object of this invention to provide an electrically
`heated smoking article in which the heating elements are
`reusable, and of which the volume of disposable portions is
`thus minimized.
`It is also an object of this invention to provide such an
`article in which generation of off-tastes as a result of
`reheating of aerosol that settles or condenses onto the
`heating elements and other permanent structural compo(cid:173)
`nents of the article is minimized.
`It is a further object of this invention to provide manu(cid:173)
`facturing processes for such an article that can be imple(cid:173)
`mented using conventional high-volume assembly machin(cid:173)
`ery.
`In accordance with this invention, there is provided a
`removable tobacco flavor unit for use in a smoking article
`for delivering to a smoker a tobacco flavor substance, the
`article having a plurality of permanent electrical heating
`means disposed in a permanent cavity. The removable
`tobacco flavor unit includes a carrier having a first end and
`a second end and having a first surface and a second surface,
`50 the first surface defining a :flavorant cavity for generating the
`tobacco flavor substance between said first end and said
`second end, and the second surface adapted to be disposed
`adjacent the plurality of electrical heating means. Tobacco
`flavor generating medium is disposed on the first surface of
`55 said carrier. When any one of the plurality of electrical
`heating means is activated, a respective fraction of said
`tobacco flavor medium in thermal transfer relationship with
`said one of said heating means is heated, generating a
`predetermined quantity of tobacco flavor substance for
`60 delivery to the smoker. Filtering means for filtering the
`predetermined quantity of tobacco flavor substance prior to
`smoking by the smoker is also provided by the tobacco
`flavor unit.
`A method and apparatus for manufacturing She remov-
`65 able tobacco :flavor unit are also provided.
`In accordance with the present invention there is also
`provided a permanent heater fixture for use in a smoking
`
`Ex. 2004-0015
`
`

`

`5,730,158
`
`4
`FIG. 10 is a longitudinal cross-sectional view of the
`preferred embodiment of a permanent heater unit for the
`"center draw" embodiment of the present invention;
`FIG. llA is a radial cross-sectional view of the permanent
`S heater unit ofFIG.10, taken from line llA-llAofFIG. 10;
`FIG. llB is a radial cross-sectional view of the permanent
`heaterunitofFIG.10, taken from line llB-llB ofFIG.10.
`FIG. 12 is a schematic diagram of a preferred embodiment
`of a control circuit for use in the present invention; and
`FIG. 13 is a schematic diagram of a preferred embodiment
`of the timing network of the control circuit of FIG. 12.
`
`DEfAil.ED DESCRIPTION OF THE
`INVENTION
`
`3
`article for delivering to a smoker a tobacco flavor substance,
`the article having a removable tobacco flavor unit that has
`tobacco flavor medium disposed on a first surlace of a
`carrier. the carrier having a second surface opposed to the
`first surlace. The permanent heater fixture includes a heater
`base defining a first end of a cavity for receiving the
`removable tobacco flavor unit, the cavity having an air
`passageway from the first end to a second end for allowing
`air to pass therebetween. The fixture also includes a plurality
`of permanent electrical heaters disposed on the heater base, 10
`the heaters each having a surface adapted to be disposed
`adjacent the second surface of the carrier. When any one of
`said plurality of electrical heating means is activated, a
`respective fraction of said tobacco flavor medium in thermal
`transfer relationship with said one of said heating means is 15
`heated, generating a predetermined quantity of tobacco
`flavor substance for delivery to the smoker.
`The present invention further includes a smoking article
`for delivering to a smoker a tobacco flavor substance. The
`article can include both the permanent heater fixture and the
`removable tobacco flavor unit of the present invention.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The above and other objects and advantages of the present
`invention will be apparent upon consideration of the fol(cid:173)
`lowing detailed description, taken in conjunction with
`accompanying drawings, in which like reference characters
`refer to like parts throughout, and in which:
`FIG. 1 is a perspective view of an electrical smoking
`article according to this invention;
`FIG. 2 is a partially fragmentary, exploded perspective
`view of the electrical smoking article of FIG. 1;
`FIG. 3 is a radial cross-sectional view of the electrical
`smoking article of FIGS. 1 and 2, taken from line 3-3 of 35
`FIG. 2;
`FIG. 3A is a radial cross-sectional view of the electrical
`smoking article of FIGS. 1-3, taken from line 3A-3A of
`FIG. I;
`FIG. 4 is a longitudinal cross-sectional view of a "center
`draw" embodiment of the electrical smoking article of FIGS.
`1-3A. taken from line 4-4 of FIG. 2;
`FIG. 5 is a partially fragmentary, perspective view of the
`disposable tobacco flavor unit of the electrical smoking 45
`article of FIGS. 1-4, taken from line 5-5 of FIG. 2;
`FIG. 6 is a preferred embodiment of apparatus for manu(cid:173)
`facturing the center portion of the disposable tobacco flavor
`unit of the electrical smoking article of FIGS. 1-5;
`FIG. 7 is a longitudinal cross-sectional view similar to
`FIG. 4 but for a "peripheral draw" embodiment of the
`present invention;
`FIG. 8 is a partially fragmentary, perspective view of the
`disposable tobacco flavor unit of the electrical smoking
`article of FIG. 7;
`FIG. 9A is a radial cross-sectional view of the electrical
`smoking article of FIGS. 7 and 8, taken from line 9A-9A
`of FIG. 7;
`FIG. 9B is a radial cross-sectional view of the electrical 60
`smoking article of FIGS. 7 and 8, taken from line 9B-9B
`of FIG. 7;
`FIG. 9C is a radial cross-sectional view of the electrical
`smoking article of FIGS. 7 and 8, taken from line 9B-9B
`of FIG. 7 after the disposable tobacco flavor unit is inserted
`into the permanent heater portion of the electrical smoking
`article;
`
`30
`
`An electrical smoking article according to the present
`invention can be used, for example, to simulate a cigarette.
`In such a case, the tobacco flavor medium would be a
`material containing tobacco or tobacco derivatives. In accor-
`zo dance with the invention, the electrical smoking article
`would include a removable disposable unit which includes
`the tobacco flavor medium and residual aerosol filters or
`barriers to prevent undesirable deposition of aerosol con(cid:173)
`densate. The disposable tobacco flavor unit can also include,
`25 if desired, a free-flow filter for filtering main-stream aerosol
`prior to delivery to the smoker.
`The disposable tobacco flavor unit of the electrical smok(cid:173)
`ing article of the present invention is inserted into a reusable
`"permanent" portion including a source of electrical energy,
`a set of reusable heating elements, and control circuitry for
`energizing the heaters in an appropriate sequence, in
`response to manual actuation or puff-induced actuation.
`Preferably, the present invention also includes control cir-
`cuitry for delivering a predetermined amount of electrical
`energy to each heater upon actuation, independent of the
`power supply loaded voltage. Other suitable control cir-
`cuitry is also described in above-incorporated commonly(cid:173)
`assigned U.S. Pat. No. 5,060,671, which is hereby incorpo-
`40 rated by reference.
`The reusable or permanent portion includes a permanent
`cavity at the mouth end thereof for insertion of the dispos(cid:173)
`able tobacco flavor unit. The reusable heaters are disposed in
`the permanent cavity in such a way that they are in thermal
`transfer relationship with the disposable tobacco flavor unit
`when the unit is inserted into the permanent cavity. This can
`be accomplished by having the heaters protrude from the
`sides of the cavity and making the disposable unit partly
`compressible, so that the heaters press into the carrier
`50 material which supports the tobacco flavor medium, to be
`discussed below, on the tobacco flavor unit.
`When reusable heaters are used, it is important that
`condensation of aerosol onto power source components,
`control circuitry, and other permanent structural portions,
`55 and particularly the heating elements, of the article be
`minimized. Otherwise, residues from a previous use (i.e.,
`fixture contamination), which might include partially
`oxidized, pyrolized or thermally decomposed constituents of
`the tobacco flavor medium, might be reheated, possibly
`giving rise to off tastes being delivered to the smoker. Such
`residues are not of concern when the heaters are disposable,
`as in above-discussed U.S. Pat. No. 5,060,671, because
`normally they are never reheated, but may be of concern
`where reusable heaters are provided, as in the present
`65 invention.
`The permanent heaters of the present invention are iso(cid:173)
`lated from the tobacco flavor air passageway and aerosol
`
`Ex. 2004-0016
`
`

`

`5,730,158
`
`20
`
`5
`cavity. This isolation minimizes condensation of aerosol
`onto the heaters and therefore minimizes aerosol residue
`reheating and off-tastes. Additionally, a back-flow filter is
`preferably also provided to reduce or substantially prevent
`the back flow of aerosol from the tobacco flavor cavity 5
`towards the power source components and control circuit.
`Such back flow of aerosol may give rise to the generation of
`off-tastes if the aerosol is able to condense onto surfaces that
`may be elevated in temperature.
`Although the permanent heaters of the present invention 10
`are in thermal transfer relationship with the tobacco flavor
`medium, they are also separated from the tobacco flavor
`material by a carrier which supports the tobacco flavor
`medium. Such carriers should preferably be able to support
`the tobacco flavor medium when "rolled" into a tube or other
`configuration, as discussed below, should preferably be
`thermally stable so as to be able to withstand the tempera(cid:173)
`tures produced by the permanent heaters, and should pref(cid:173)
`erably also be thermally transmissive to allow the heat
`generated by the permanent heaters to be efficiently trans-
`ferred to the tobacco flavor medium. Materials which fulfill
`these characteristics include paper and paper-like materials.
`More preferably, the carrier of the present invention is
`made from a nonwoven carbon fiber mat of the type dis(cid:173)
`closed in commonly-assigned U.S. Pat. No. 5,369,723, filed 25
`concurrently herewith, and incorporated herein by reference
`in its entirety. Such mats should preferably have a thickness
`between about 0.05 mm and about 0.11 mm and be com(cid:173)
`posed of nonwoven carbon fibers (having a basis weight in
`the range of from about 6 g/m2 to about 12 g/m2 with fiber 30
`diameters between about 7 µm and about 30 µm). The
`lengths of the fibers should allow the mat to withstand the
`tensile stresses encountered during processing. Preferably,
`the mats should include a binder which is suitable for use in
`electrical smoking articles (i.e., having acceptable subjective 35
`properties).
`Tobacco flavor material which is disposed on the surface
`of the carrier of the present invention can be any material
`that liberates flavors when heated and is able to adhere to the
`surface of the carrier. Such materials include continuous 40
`sheets, foams, gels, dried slurries, or dried spray-deposited
`slurries, which may or may not contain tobacco or tobacco(cid:173)
`derived materials, and which are more fully discussed in the
`above-incorporated U.S. Pat. No. 5,369,723. It is desirable
`that the tobacco flavor material contain an aerosol precursor 45
`to deliver the tobacco flavor containing substance as an
`aerosol, so that when the smoker exhales the tobacco flavor
`containing substance, the visible condensed aerosol may
`mimic the appearance of cigarette smoke.
`Because the tobacco flavor material of the present inven- 50
`tion is disposed on the surface of the carrier material, its
`flavor delivery properties can be spatially varied to allow the
`flavor delivery profile from puff to puff to be selectively
`varied. For example, the tobacco flavor material adjacent a
`first heater can contain a first amount or type of flavorant, 55
`whereas the tobacco flavor material adjacent a second heater
`can contain a second different amount or type of flavorant.
`Thus, the flavor 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 60
`material. Of course, this particular embodiment may require
`the smoker to orient the disposable unit relative to the
`permanent heaters, when it is inserted into the permanent
`cavity, if it is desired that a particular heater heat a prede(cid:173)
`termined portion of the non-uniform tobacco flavor material. 65
`Additionally, flavor delivery can also be selectively varied
`in accordance with present invention by providing a con-
`
`15
`
`6
`trolled amount of energy to the heaters of present invention.
`For example, if the amount of energy delivered to the first
`heater (e.g., 20 Joules) is greater than the amount delivered
`to the second ( e.g., 15 Joules), then the temperature that the
`first heater will achieve will be greater than that of the
`second. Therefore, the first heater will generate more aerosol
`or flavorants than the second, assuming the temperature is
`not high enough to cause undesirable burning of the tobacco
`flavor material. In this manner the generation of aerosol or
`flavorants can be selectively controlled by varying the
`amount of energy delivery from puff to puff.
`Furthermore, flavor delivery can also be selectively varied
`in accordance with the present invention by varying the
`amount of energy delivered from disposable tobacco flavor
`unit to disposable tobacco flavor unit. For example, if the
`amount of energy delivered, per puff, to a first disposable
`unit (e.g., 20 Joules/puff) is greater than the amount deliv(cid:173)
`ered to a second (e.g., 15 Joules/puff), then the temperature
`that the first unit will achieve will be greater than that of the
`second. Therefore, the first unit will generate more aerosol
`or flavorants per puff than the second, assuming the tem(cid:173)
`perature is not high enough to cause undesirable burning of
`the tobacco flavor material. In this manner the generation of
`aerosol or flavorants can be selectively controlled by Vary(cid:173)
`ing the amount of energy delivery from unit to unit.
`Residual aerosol which condenses onto the permanent
`heaters of the present invention can be partly removed by the
`wiping action of the inner part of a new tobacco flavor unit
`against the heaters as the new tobacco flavor unit is inserted.
`Thus, the insertion end of the tobacco flavor unit pushes any
`residues on the heater surfaces toward the ends of the
`heaters. For this reason, the tobacco flavor unit should be
`relatively firm, and the heaters should preferably have a
`smooth surface finish to assure that the wiping action is
`effective.
`The parameters of the permanent heaters are chosen to
`allow delivery of an effective amount of tobacco flavor
`substance--e.g., an aerosol containing tobacco flavors-to
`the smoker under standard conditions of use. For example,
`it may be desirable to deliver 1 to 2 mg of aerosol to a
`smoker during a 35 ml puff having a two-second duration.
`It has been found that in order to achieve such delivery,
`the heaters should be able to reach a temperature of between
`about 200° C. and about 700° C. when in thermal transfer
`relationship with the tobacco flavor medium. Further, the
`heaters should preferably consume between about 5 to 40
`Joules of energy, more preferably about 10-25, and even
`more preferably about 20 Joules.
`Heaters having such characteristics preferably have an
`active surface area of between about 3 mm2 and about 20
`mm2 and preferably have a resistance of between about 0.5
`n and about 3.0 n. More preferably, the heaters should have
`a resistance of between about 0.8 n and 2.1 n. Of course,
`the heater resistance will also be dictated by the particular
`power source that is used to provide the necessary electrical
`energy to heat the heaters. For example, the above heater
`resistances correspond to embodiments where power is
`supplied by four series-connected nickel-cadmium battery
`cells with a total power source voltage of approximately 4.8
`to 5.8 volts, as discussed below. In the alternative, if six or
`eight such series-connected batteries are used, the heaters
`should preferably have a resistance of between about 3 and
`5 ohms or between about 5 and 7 ohms, respectively.
`The materials of which the heaters are made are prefer(cid:173)
`ably chosen to assure reliable repeated uses of at least 1,800
`on/off cycles without failure. The heater materials are also
`
`Ex. 2004-0017
`
`

`

`5,730,158
`
`7
`chosen based on their reactivities, to assure that they will not
`react with the tobacco flavor medium at any temperature
`likely to be encountered. Similarly, the heaters themselves
`should not evolve any off-gases compounds even when
`heated out of the presence of the tobacco flavor medium. 5
`Alternatively, heaters that might otherwise evolve off-gases
`could be encapsulated in an inert heat-conducting material
`such as a suitable ceramic material.
`Based on these criteria. materials for the electric heating
`means of the present invention include carbon, graphite, 10
`stainless steel, tantalum. metal ceramic matrices, and metal
`alloys. such as iron alloys, and nickel-chromium alloys.
`Suitable metal-ceramic matrices include silicon carbide alu(cid:173)
`minum and silicon carbide titanium. Of the listed materials,
`stainless steel and the iron or chromium alloys should 15
`preferably be encapsulated in a suitable ceramic material
`because of their poor oxidation and corrosion resistance at
`high temperatures. Suitable ceramic materials for encapsu(cid:173)
`lation include silica, alumina. and sol gels.
`Most preferably, however, the electric heaters of the 20
`present invention are made from doped silicon. Such heaters
`are described in copending commonly-assigned U.S. patent
`application Ser. No. 07 /943.505. filed concurrently herewith,
`and hereby incorporated by reference in its entirety. That
`application discloses electrical heaters which are made from 25
`silicon semiconductor material which is doped with phos(cid:173)
`phorous impurities to a level in the range of from about
`5xl018 impurities/cm3 to about 5xl019 impurities/cm3, cor(cid:173)
`responding to a resistivity in the range of from about 1x10-2
`Q-cm to about lx10-3 Q-cm, respectively.
`A first preferred embodiment of an electrical smoking
`article 10 according to the present invention is shown in
`FIGS. 1-5. Article 10 includes reusable or "permanent"
`portion 20 and disposable tobacco flavor unit 21 which is
`received in a permanent cavity 30 at the mouth end of
`portion 20.
`Reusable portion 20 includes, at the end remote from the
`mouth end. a power source 22, which could include a
`battery, a capacitor or both. The battery could be 40
`replaceable, rechargeable or both. If the