Tobacco product

This invention provides a smoke vector for a cigarette, and the like, for modifying or altering the mainstream smoke at or near the combustion zone or burning zone. The smoke vector comprises a thin walled elongated, impervious tube-like member or vector which is hollow and empty. The vector extends longitudinally through the cigarette and terminates with an impervious mouth end. During an indrawn breath by the smoker, the products of the combustion of tobacco in systemic heat is below the formation temperatures of temperature dependant hazardous chemicals.

BACKGROUND 
This invention relates to a smoke vector for modifying the smoke of tobacco 
products. In its more specific aspect, this invention relates to a smoke 
vector which mechanically and chemically modifies and alters the smoke 
drawn in by the smoker of a cigarette or the like. 
U.S. Pat. No. 3,258,015, dated June, 1966, to Ellis et al. describes a 
smoking device which operates to release a nicotine flavored vapor from a 
nocotine-releasing material produced by the smoldering of tobacco when the 
smoker draws through a tube. It should be noted that Ellis et al. 
specifies that none of the products of combustion are drawn in by the 
smoker. Notwithstanding the benefits to the smoker who uses such a device, 
the annual increase in the use of cigarettes whose products of combustion 
are drawn in by smokers demonstrates a need to protect this latter group 
of smokers from the hazardous products of combustion produced by the 
cigarettes they smoke. 
While this invention is described hereinafter with particular reference to 
cigarettes, it should be understood that the invention is also applicable 
to cigars and cigarillos as well. 
Smoking has become a widespread habit, but in recent years has come under 
severe criticism as being dangerous to the smoker's health. Tobacco smoke 
is an aerosol comprising gas and semi-liquid particles measuring from 
about 0.1 to over 1 micron. The burning zone has a temperature range of 
from 875.degree. C. to 1050.degree. C. Within this temperature range both 
oxidation by burning and thermal degradation due to absence of oxygen 
occur but in different zones. The high temperature zone is in the axial 
center and is the region of thermal degradation of tobacco-- a reductive 
process. 
Adjacent to the burning zone upstream of the burn the products of 
combustion and degradation are pyrolized and distilled and the smoke 
constituents drawn up the cigarette are re-pyrolized and re-distilled as 
the burning zone moves rearward along the cigarette. 
Thus, a number of reactions are occuring such as dehydration, 
de-hydrogenization, de-amination, cracking and pyrosynthesis, and in 
general, at the center of the burn, thermal degradation. 
As a result of thermal degradation and pyrosynthesis, the smoke inhaled or 
sucked in by the smoker during a puff, sometimes called mainstream smoke 
", contains numerous chemicals such as paraffins, low molecular weight 
carboxyl compounds, amines, pyridine, terpenes, polyaromatic hydrocarbons, 
and nicotine as well as carbon monoxide and particulate matter. Some or 
many of these chemicals are harmful to the smoker's health. 
In order to diminish this health hazard, cigarettes are commonly provided 
with a filter at the upper or mouth end. These filters, which are well 
known in the art, remove one or more of these constituents from the smoke 
by mechanical or physical means and/or by absorption, thereby decreasing 
the amount of harmful matter drawn in by the smoker. Notwithstanding the 
effectiveness of these filters, harmful constituents in the smoke stream 
are decreased at best and a substantial amount of these constituents are 
inhaled by the smoker. Cigarette filters are, therefore, supportive of 
efforts to diminish the hazard to health from smoking, but are not 
corrective. Corrective measures require the elimination of harmful 
chemicals, not their reduction. In order to eliminate these chemicals, it 
is necessary to understand the theory of combustion of cigarettes which 
gives rise to their formation. It therefore would be of value to explain 
this theory in order to comprehend the corrective objectives and mechanism 
of this invention. 
It has been established that many harmful chemicals in cigarette smoke are 
formed in the high temperature, oxygen-deficient zone immediately 
downstream of the burn. This region is commonly known as the coal. The 
formation of many of these chemicals is temperature dependant in this 
oxygen-deficient zone, being the products of thermal degradation of 
tobacco. 
Attempts to reduce the temperature of the coal using additives has met with 
little success. This is also true of attempts to change the combustion 
characteristics of cigarette tobacco. 
A more complete understanding of the cigarette as a combustion system is 
required to pinpoint the cause and achieve a resolution to thermal 
degradation of tobacco. 
There are two types of combustion systems. One system is a stationary-fuel, 
moving-combustion zone system such as exemplified by smoldering rope, 
explosive fuse cord, candles, etc. The other system is a 
stationary-combustion zone, moving-fuel type such as gas burners, welding 
torches and oil burners. The combustion characteristics of the burner 
system are not affected by the combustion system to which the burner 
belongs, (although the stationary combustion-zone, moving-fuel combustion 
system permits greater fuel velocities). 
Cigarettes are of the stationary-fuel, moving-combustion zone type of 
system. 
There is a burner system in which the configuration of the burner has an 
effect on the combustion characteristics. It is the circular solid (as 
differentiated from hollow) combustion system. Circular burners, as do all 
burners, release heat in all directions. The released heat from the 
perimeter of the circular solid burner moves outwardly to the surrounding 
air and inwardly toward the axial center of the fuel. Adjacent burning 
points on the perimeter mutually exclude heat transfer from each other 
since they are both burning at the same temperature. 
Heat released inwardly is transferred by conduction to the center, which 
acts as a collection point for heat from all points on the burning 
perimeter. The center, being the point of convergence of heat, is raised 
to a temperature substantially higher than any point on the perimeter. 
The center releases its heat wherever it can. Typical directions of heat 
release are upward, forming a pre-heating zone for fuel, and downward for 
cooling by air, and laterally in all directions. Heat moving downwardly 
moves out from the point of convergence, radially forming a curved conical 
ember. Heat moving out laterally, moves out radially toward the burning 
perimeter. Since the burn itself is a source of heat, the opposing 
movement of heat from the point of convergence and from the burning 
perimeter, reaches a point of equilibrium, which, in a round burner, is a 
circle of equilibrium concentric with the burning perimeter. 
The distance of a point on the circle of equilibrium from a point on the 
burning perimeter and the point of convergence of heat is dependant upon 
the temperature of the point of convergence and that of a point on the 
burning perimeter. The greater the heat of the coal in relation to a point 
on the perimeter, the closer the circle of equilibrium will be to the 
perimeter; conversely, the lower the heat of the coal, the closer will be 
the position of the circle of equilibrium to the coal. 
Heat from any point on the burning perimeter radiated outwardly is 
determined by the temperature in the zone toward which the heat is moving. 
Thus, adjacent points on the burning perimeter mutually exclude heat 
transfer from one another since they are both at the same temperature. 
Additionally, the higher the temperature of the circle of equilibrium or 
the closer the circle of equilibrium to the burning perimeter, the less 
heat will move inward from the burning perimeter and the more heat will 
move outward from it. The outward release of heat from the burning 
perimeter warms and rarifies approaching air, thereby depleting the oxygen 
supply available for combustion. 
The proximity of the circle of equilibrium to the burning perimeter, then, 
is a determinant of the rate of combustion. The temperature of the coal, 
being a determinant of the circle of equilibrium, is a determinant of the 
rate of combustion, and a secondary determinant of the rarefaction of 
approaching air and its percentage supply of oxygen for burning. 
In all of the above, cigarettes behave as typical circular solid (as 
opposed to hollow) combustion systems. While the cigarette tobacco 
smolders, side stream smoke shows heat being released to air; while below 
the burn, the glowing ember maintains a constant length as the burn moves 
backward along the fuel. The constant length of the glowing ember is an 
indication of the existence of equilibrium between heat produced and heat 
released during the smolder. 
During smolder, both heat produced by burning and heat removed by ambient 
air at the face of the ember, proceed at atmospheric pressure in ambient 
air. The rate of heat removal from the coal determines the temperature of 
the coal and the proximity of the circle of equilibrium to the burning 
perimeter, and in turn the rarefaction of approaching air by the heat of 
the burn, and therefore the rate of burning. By itself, therefore, a 
cigarette smoldering arrives at a constant rate of burning, and this is in 
equilibrium with the rate of cooling. 
The effect of smoldering upon the cigarette as a solid circular combustion 
system is different from what the effect would be on a hollow circular 
combustion system. The cigarette, when smoldering, behaves as a typical 
solid circular combustion system in that heat from the burning perimeter 
moves in to the center and converges there, with the result that the fuel 
(tobacco) is raised to an exponentially higher temperature than any 
segment of the circle. For purposes of convenient identification this heat 
at the point of convergence can be called systemic heat since it is due to 
the characteristics of the combustion system to which the cigarette 
belongs. 
When a smoker takes a puff and draws in smoke, he sharply increases the 
velocity of air moving into the burning perimeter by suction. Rarefaction 
of approaching air is overcome and the rate of burning is greatly 
accelerated. The smoker's draw upsets the equilibrium maintained by the 
cigarette in smolder by altering the condition that produce it. 
Since the rate of cooling proceeds at atmospheric pressure in ambient air, 
the accelerated burn rate produces more heat than can be released in the 
same atmospheric conditions as smolder in the same increment of time as 
the draw. Thus, the heat release mechanism is overwhelmed during the draw. 
Since the atmosphere cannot absorb the heat as quickly as it is produced 
during a draw, there is a time delay for release of heat. During this time 
delay more heat is being added by the rest of the draw to the heat not yet 
released because of the time delay. This causes a rise in temperature 
above the already high temperature of systemic heat. 
This additional heat rise is sufficient to cause the tobacco in the center 
holding the heat to decompose. The products of this decomposition are 
harmful to the smoker. For purposes of convenient identification, heat 
rise caused by delay in heat release during a draw can be called draw 
heat. 
In order to prevent the thermal decomposition of tobacco into products 
harmful to the smoker it is necessary to prevent the tobacco from reaching 
the temperature of decomposition. This can only be accomplished by 
preventing the coupling of systemic heat with draw heat. 
It is the object of this invention to redirect the draw heat more quickly 
to the atmosphere thus precluding a time delay for release, thereby 
preventing coupling draw heat with systemic heat. 
The ambient air that surrounds a burning cigarette absorbs the heat. The 
air molecules absorb the heat at essentially a fixed rate: each molecule 
absorbs a fixed amount of heat. The increased molecular activity caused by 
the absorption of heat causes the air envelope to expand and move away 
from the source of heat, while cooler air moves in to replace the 
expanding air. In a continuing system, this becomes a preferential 
direction of flow. 
In a circular system such as a cigarette, the movement of cool air into the 
combustion zone is radially inward. This radial movement has the effect of 
narrowing the space in which the hot expanding gas is moving away. The net 
effect is to force the expanding gases into a column, while at the same 
time increasing the axial outward flow velocity of the hot gases. 
The higher the temperature of the source of heat relative to the 
surrounding air the greater the amount of molecules will be needed to 
remove the heat, and therefore the greater the volume of air to contain 
the greater amount of molecules. This is accomplished spontaneously in 
free air by increased velocity of convection currents to bring a greater 
amount of cool air across the face of the heat source. 
It is advantageous, therefore, to make use of the added air flow of 
convection currents by increasing the temperature differential between the 
end of the cigarette and the atmosphere. 
In cigarettes, as they are currently manufactured, systemic heat moves from 
the point of convergence radially outward in all directions by conduction. 
There are temperature gradients between the point of convergence and the 
greater outside face of the ember meeting the air. There is also a 
temperature drop from the coal to the outside face due to distribution of 
heat to a greater total area. 
The resulting temperature drop and point by point distribution of heat on 
the outside face of the ember results in a lowered temperature 
differential between any one point and the atmosphere. This low 
differential is the determinant for convection current velocity. By reason 
of this invention the smoke vector provides the means to increase the 
temperature differential between the end of the cigarette and the 
atmosphere thus accelerating convection currents and drawing cool air to 
the end of the cigarette for accelerated heat removal. 
Accelerating heat removal will have the effect of preventing coupling of 
draw heat to systemic heat thereby preventing the decomposition of tobacco 
in the coal into harmful chemicals. 
THE INVENTION 
The invention comprises a thin walled cylinder or smoke vector disposed in 
the longitudinal axis of the cigarette. The cylinder or vector is sealed 
at the mouth end and open at the front end, and it is substantially 
impervious relative to the draw strength of the smoker. The vector is made 
of an inert material and desirably may be segmented for removal of 
unneeded sections as the cigarette burns down. Further, the vector 
exhibits a relatively high specific heat so as to be essentially 
transparent to heat whereby there is established a preferentail direction 
of flow of heat from the burning tobacco through the wall of the vector to 
the air inside the tube. 
In order to maintain the largest differential in heat between the air in 
the tube and the air outside the cigarette it is essential that heat 
transported through the wall of the vector be transferred directly to air 
and that there be no material between the interior wall of the vector and 
the air inside the vector which might absorb heat, since any absorption of 
heat would lower the differential between the high temperature inside the 
vector and the free air outside the cigarette. Thus, air inside the vector 
is in direct contact with all points of the interior wall of the vector 
with nothing else interposed. 
With this construction, the preferential direction of flow is established 
as a venturi effect, accomplishing a temperature decrease in the coal. 
During a draw, heat added to the point of convergence will first impinge 
the outer face of the vector and then pass readily by conduction to the 
inner face of the cylinder. The heated interior walls of the cylinder will 
be raised to a high temperature as the point of convergence of heat. With 
the increase of heat during the draw the air inside the cylinder will 
increase in temperature creating a larger differential with respect to the 
free air outside the open end of the vector. This increased differential 
will accelerate both the movement of heated air away from the open end, 
and the radial movement of cool air inward to replace the warmed air, thus 
maintaining atmospheric pressure. This continuous and accelerated flow 
will remove the heat added to the cigarette by the increased rate of 
burning during the draw and prevent the coal from reaching the temperature 
of thermal decomposition.

Broadly my invention for a smoke vector comprises a longitudinally disposed 
insert extending substantially the length of the cigarette. The smoke 
vector is concentrically arranged in the body of the cigarette so as to be 
surrounded by tobacco. It is essential that the vector be sealed at the 
mouth end and be open at the front end in order to establish the proper 
convection currents so that the coal will remain below its thermal 
decomposition temperature as explained above. 
In order to describe the invention in greater detail, reference is now made 
to the drawings wherein like reference numerals designate similar parts 
throughout. The ciarette, shown generally by the numeral 10, is provided 
with a typical paper wrapper 12 as the outer shell to encase the tobacco 
14. Smoke vector 16 extends longitudinally through the center of the 
cigarette so as to be concentrically arranged therewith. The vector 
extends from the front or burning end to the upper or mouth end of the 
cigarette so as to be substantially coterminous with the wrapped tobacco. 
The vector is sealed or capped with a substantially impervious cap member 
or seal 17 at the mouth end. 
The vector 16 may be formed of a ceramic or metal structure, for example, 
and must be capable of withstanding the temperature of burning of a 
cigarette and may include, for example, fused quartz, or stainless steel. 
The vector can be of granular construction and be pressed or molded to 
shape, or may be held together with high temperature cement or the vector 
may be made of rigidized foam. The advantage of granular or rigidized foam 
construction is that as the cigarette burns down the used portion of the 
vector may be tapped off making the shortened remaining vector more 
efficient. The vector desirably may have dimensions of 2 1/2 or 3 
millimeters in diameter, and have a wall thickness that may vary from 1/3 
millimeter to 1 millimeter. The empty center of the vector may be 1/2 
millimeter to 1 and 1/3 millimeter. Variations in performance may be 
accomplished by varying the outside diameter and wall thickness of the 
vector. 
Cigarette 10 may be provided with a conventional mouthpiece (not shown) 
formed of a substantially impervious material such as paper, to prevent 
the intake of air when the smoker draws on the cigarette. The mouthpiece 
spreads and cools the indrawn smoke and may also include a filter for 
smoke. 
According to the embodiment shown in FIG. 3, the smoke vector 20 is a 
cylinder or tube comprising a plurality of segments extending beyond the 
tobacco that may be tapped off. In this manner, the unneeded portion of 
the smoke vector is continuously removed, and the remaining vector kept 
efficient. 
Although the vector is preferentially of circular cross section, as is the 
preferential shape of cigarettes, the vector may be of any desired 
configuration such as elliptical. 
It will be observed that the smoke vector has the distinct advantage of 
providing a technical and economic means for modifying or altering smoke 
so that it is less harmful to the smoker. The mainstream smoke is modified 
to less harmful chemicals during pyrolisis or distillation. Certain 
harmful chemicals may be prevented from forming, while others may be 
changed, if formed, during combustion. 
It will be understood that the smoke vector described may be varied without 
departing from the invention.