Tobacco – Tobacco users' appliance – Device used for smoking
Reexamination Certificate
2001-03-23
2004-02-10
Walls, Dionne A. (Department: 1731)
Tobacco
Tobacco users' appliance
Device used for smoking
C131S361000, C131S360000
Reexamination Certificate
active
06688313
ABSTRACT:
FIELD OF INVENTION
The present invention relates to electrical smoking systems and methods of increasing delivery in electrical smoking systems.
BACKGROUND OF INVENTION
Traditional cigarettes are consumed by lighting an end of a wrapped tobacco rod and drawing air predominately through the lit end by suction at a mouthpiece end of the cigarette. Traditional cigarettes deliver smoke as a result of combustion, during which a mass of tobacco is combusted at temperatures which often exceeds 800° C. during a puff. The heat of combustion releases various gaseous combustion products and distillates from the tobacco. As these gaseous products are drawn through the cigarette, they cool and condense to form a smoke containing the tastes and aromas associated with smoking. Traditional cigarettes produce sidestream smoke during smoldering between puffs. Once lit, they must be fully consumed or be discarded. Relighting a traditional cigarette is possible but is usually an unattractive proposition to a discerning smoker for subjective reasons (flavor, taste, odor).
In an electrical smoking system, it is desirable to deliver smoke in a manner that meets the smokers experiences with more traditional cigarettes, such as an immediacy response (smoke delivery occurring immediately upon draw), a desired level of delivery (which correlates with FTC tar level), together with a desired resistance to draw (RTD) and consistency from puff to puff and from cigarette to cigarette.
Commonly assigned U.S. Pat. Nos. 5,388,594 and 5,692,525 disclose electrical smoking systems and methods of manufacturing a cigarette, which patents are incorporated by reference. The former patent describes an electrical smoking system including a novel electrically powered lighter and a novel cigarette that cooperates with the lighter. The preferred embodiment of the lighter therein included a plurality of metallic serpentine heaters disposed in a configuration that slidingly receives a tobacco rod portion of the cigarette. The preferred embodiment of the cigarette therein comprised a tobacco-laden tubular carrier, a cigarette paper overwrapped about the tubular carrier, an arrangement of flow-through filter plugs at a mouthpiece end of the carrier and a filter plug at the free (distal) end of the carrier. The cigarette and the lighter were configured such that when the cigarette is inserted into the lighter and as individual heaters are actuated for each puff, localized charring occurs at spots about the cigarette in the locality where each heater was bearing against the cigarette (hereinafter referred to as a “heater footprint” or “char zones”). Once all the heaters had been actuated, the cigarette is discarded.
In the latter patent, the cigarette includes a tobacco plug and the cigarette and the heater fixture are mutually configured such that the heater footprints (char zones) at least partially overlap the tobacco plug as well as a hollow portion of the tobacco rod. Such arrangement provides an immediacy of response from the early initiation of pyrolysis at the void, together with inclusion of a fuller flavor contribution from the plug of tobacco(s).
It has been desirous to produce an electrical smoking system of the type described above that produces delivery levels of substantially greater than 3 milligrams tar (FTC). A greater segment of smokers prefer the higher levels of delivery from their more traditional cigarettes of choice. Obtaining such levels of delivery in electrical smoking systems has heretofore been a challenging proposition.
For example, the previously described electrical smoking systems are battery operated, so that the total energy expended per puff needs to be kept at acceptable levels. Too much power application in the heater elements during a puff can lead to burn-throughs and sometimes undesired degrees of combustion.
In systems such as taught in commonly assigned U.S. Pat. No. 5,692,525, in which heater footprints (char zones) at least partially overlap a hollow portion of the tobacco rod and partially overlap a tobacco plug, burn-throughs will usually first appear in the region of the hollow portion of the tobacco rod. Upon such occurrence, the smoke tends to be hotter than the other puffs, with less contribution of the fuller flavor usually generated by the heating of the tobacco plug portion of the cigarette rod. Consistency in the smoking experience are compromised if burn-throughs are not somehow avoided.
In commonly assigned U.S. Pat. No. 5,388,594, the smoked portion of the tobacco rod is preferably entirely hollow and the heater footprint is entirely superposed over a the hollow portion of the tobacco rod. Burn-throughs in the “wholly hollow” system of U.S. Pat. No. 5,388,594 tend to make the smoke all the more hot and/or harsh tasting. Providing expedients to increase delivery in the “wholly hollow” system of U.S. Pat. No. 5,388,594, such as providing perforations as suggested at column 10, lines 36-51 thereof, aggravate the risks of burn-throughs, with adverse consequences upon taste and consistency.
Resistance to draw (RTD) of traditional cigarettes is the pressure required to force air through the full length of a cigarette at the rate of 17.5 ml per second. RTD is usually expressed in inches or millimeter of water. Smokers have certain expectations when drawing upon a traditional cigarette in that too little RTD or too much can detract from smoking enjoyment. More traditional cigarettes of moderate delivery have RTD's generally within the range of approximately 100 to 130 mm water.
Establishing a desired RTD in electrical smoking systems is complicated by the circumstance that in smoking systems such as shown in U.S. Pat. Nos. 5,388,594 and 5,692,525, air is first drawn through passages within the cigarette lighter before being drawn out through the cigarette. The filter tipping of the cigarettes of those systems are preferably flow-through and/or low particulate efficiency filters so as to minimize loss of whatever smoke is produced. Such filters produce little pressure drop and therefore do not contribute much RTD. Consequently, prior practices have included the establishment of RTD (or pressure drop) predominantly in the lighter portion of the electrical smoking system, such as with an annular frit (porous body) adjacent the air admission port of the lighter as taught in commonly assigned U.S. Pat. No. 5,954,979. Because pressure drop varies widely with any change in size of the constriction, it has been found that the use of frits or other forms of tiny flow constrictions in the lighter body must be manufactured with care. It therefore adds expense and other production and quality concerns. Furthermore, tiny flow passages are prone to clog, particularly in lighters wherein any smoke is allowed to linger after completion of a puff.
OBJECTS AND SUMMARY OF INVENTION
An object of the present invention is to provide a cigarette containing cut filler or other form of shredded tobacco, which cigarette is adapted to cooperate with an electrical lighter and render satisfying levels of delivery and taste.
Another object of the present invention is to provide a cigarette for an electrical smoking system which includes cut filler, yet provides improved consistency in delivery from puff to puff.
Another object of the present invention is to provide a cigarette adapted for use in electrical smoking systems, which cigarette is resistive to breakage during the withdrawal of the cigarette from the lighter thereof.
It is still a further object of this invention to provide a novel cigarette that is operative with an electrical lighter and conducive to cost-effective methods of manufacture, even at production speeds.
These and other objects are achieved with the present invention which provides an electrical smoking system comprising a cigarette and an electric lighter, wherein the cigarette comprises a tubular tobacco mat partially filled with material tobacco so as to define a filled tobacco rod portion and an unfilled tobacco rod portion. The filled tobacco rod portion is situated adjacent
Counts Mary Ellen
Crowe William James
Franklin Traci L.
Hayes Patrick H.
Lilly, Jr. A. Clifton
Burns Doane , Swecker, Mathis LLP
Philip Morris Incorporated
Walls Dionne A.
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