CIGARETTES A BOUT FILTRE AVEC CHAMBRE A AIR

FILTER CIGARETTES WITH AIR CHAMBERS

Abrégé anglais

A filter cigarette has an outer combustible tube which is substantially filled
with tobacco.
There is a second cylindrical member axially aligned with the first
cylindrical member and
spaced-apart therefrom. The second member is substantially filled with a
filtering medium.
A third cylindrical member is between the first member and the second member
and is
connected to the first member and the second member. The third member has an
outer tube
and an empty interior, providing an air space between the tobacco and the
filtering medium.
There may be an aperture extending through the outer tube, allowing air to be
drawn into the
space when a smoker draws on the cigarette. This cools smoke in the tubular
member and
thereby condenses harmful products out of the smoke before the smoke is drawn
through the
filter.

Revendications

-5-
WHAT IS CLAIMED IS:
1. A filter cigarette, comprising:
a first cylindrical member having an outer combustible tube which is
substantially
filled with tobacco;
a second cylindrical member axially aligned with the first cylindrical member
and
spaced-apart therefrom, the second member being substantially filled with a
filtering
medium; and
a third cylindrical member which is between the first member and the second
member and is connected to the first member and the second member, the third
member having an outer tube and an empty interior, providing an air space
between
the tobacco and the filtering medium.
2. The cigarette as claimed in claim 1, wherein the third cylindrical member
has an
aperture extending through the outer tube, allowing air to be drawn into the
air space
when a smoker draws on the cigarette.
3. A method of reducing harmful products in cigarette smoke, comprising the
steps of:
providing a filter cigarette, having a portion filled with tobacco and a
filter, with an
empty tubular member between the portion filled with tobacco and the filter;
providing an aperture in the tubular member; and

-6-
drawing air through the aperture and into the tubular member, when a smoker
draws
on the cigarette, to cool smoke in the tubular member and thereby condense the
harmful products out of the smoke before the smoke is drawn through the
filter.
4. The method as claimed in claim 3, wherein the harmful products include
nicotine.

Description

CA 02271432 1999-OS-11
FILTER CIGARETTES WITH AIR CHAMBERS
BACKGROUND OF THE INVENTION
S This invention relates to cigarettes and, in particular, to cigarettes
having provision for
reducing wastage of tobacco and for reducing harmful products in the smoke.
Filter cigarettes usually comprise a first cylindrical portion in the form of
a cigarette paper
tube filled with tobacco and a second portion containing a filtering medium. A
smoker rarely
smokes a cigarette right up to the second portion containing the filtering
medium. This is
because the second portion is typically too short to comfortably hold when the
cigarette is
being smoked. This results in a waste of tobacco which is a relatively
expensive commodity
in many parts of the world.
In addition, many attempts have been made to reduce the proportion of harmful
products,
such as nicotine, in cigarette smoke. These efforts have frequently revolved
around attempts
to produce better filtering mediums or selecting tobaccos which produce a
smaller proportion
of such harmful products when combusted. These efforts have not been
altogether
successful. Frequently tobaccos which produce less harmful smoke are perceived
as inferior
by the smoker. Attempts to improve the filtering mediums may result in
detrimental effects
such as increasing the effort required by the smoker to draw smoke through the
filter.
Attempts have been made to provide cigarettes with reduced wastage of tobacco.
For
example, United States Patents Number 4759380 to Norman et al. shows a
cigarette which
has a portion between the normal tobacco portion and the filter which is
filled with smokable
material including cheaper tobaccos or other materials. However even these
materials have
a cost and can have a detrimental effect on the taste of the smoke.
Furthermore, such an
arrangement provides no advantage in cooling the smoke and thereby reducing
the proportion
of harmful products.

CA 02271432 1999-OS-11
-2-
United States Patent Number 4121597 to Shin shows a space in the filter
itself. However
this is not between the filter and the tobacco. Also there is no aperture to
draw air into the
space and thereby further cool smoke to reduce harmful contents.
Accordingly, it is an object of the invention to provide an improved filter
cigarette which
reduces wastage of tobacco.
It is also an obj ect of the invention to provide an improved filter cigarette
which reduces the
content of harmful materials in the smoke, such as nicotine.
It is a further object of the invention to provide an improved filter
cigarette which is simple
in construction and economical to produce and manufacture.
SUMMARY OF THE INVENTION
According to one aspect of the invention, there is provided a filter cigarette
which includes
a first cylindrical member having an outer combustible tube which is
substantially filled with
tobacco. There is a second cylindrical member axially aligned with the first
cylindrical
member and spaced-apart therefrom. The second member is substantially filled
with a
filtering medium. A third cylindrical member is located between the first
member and the
second member and is connected to the first member and the second member. The
third
member has an outer tube and an empty interior, providing an air space between
the tobacco
and the filtering medium.
According to another aspect of the invention, there is provided a method of
reducing harmful
products in cigarette smoke. The method includes steps of providing a filter
cigarette having
a portion filled with tobacco and a filter with an empty tubular member
between the portion
filled with tobacco and the filter. An aperture is provided in the tubular
member. Air is
drawn through the aperture and into the tubular member when a smoker draws on
the

CA 02271432 1999-OS-11
-3-
cigarette to cool smoke in the tubular member and thereby condense the harmful
products
out of the smoke before the smoke is drawn through the filter.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure 1 is an isometric view of a filter cigarette according to an embodiment
of the
invention; and
Figure 2 is a sectional view thereof taken along line 2-2 of Figure 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, these show a filter-type cigarette 10 which
includes a first
cylindrical member 12 which is conventional for most cigarettes. It includes
an outer
combustible tube 14, of conventional cigarette paper in this embodiment. The
tube is filled
with conventional cigarette tobacco 16.
There is a second cylindrical member 20 which is similar in construction to a
normal
cigarette filter. It has an outer tubular portion 22 and is filled with a
conventional filtering
medium 24. As described thus far, cigarette 10 is generally conventional.
However, cigarette 10 varies from the prior art by having a third cylindrical
member 30
between the first member 12 and the second member 20. The third member is
connected to
the first member at a first end 32 thereof and is connected to the second
cylindrical member
at second end 34 thereof. In this particular example, the third member has an
outer tubular
cover 40 which is of the same material as tubular portion 22 of the
cylindrical member 20.
In fact, in this example, cover 40 and tubular portion 22 comprise a single
piece of material.

CA 02271432 1999-OS-11
-4-
However, it should be understood that these could be separate pieces and that,
in other
embodiments, the third member could be reinforced with other layers of
material inside,
outside, or adjacent to tubular portion 22. Likewise the cover 40 could
overlap combustible
tube 14 of the first cylindrical member 12. In this example member 30 is 1 /4
the total length
of member 30 plus member 12 combined, although this proportion could vary in
other
embodiments.
There is a small aperture 50 in the wall of cover 40 which communicates
inwardly with its
empty interior 54. The empty interior 54 provides an air space between tobacco
16 and
filtering medium 24. This aperture 50 may be omitted in an alternative
embodiment.
In use, a smoker places tubular portion 22 of the cigarette in his or her
mouth and smokes in
the conventional manner. In the process, smoke is drawn through the tobacco 16
and into
interior 54 of the third cylindrical member as indicated by arrows 60. The
smoke is drawn
out of the end of the cigarette into the smoker's mouth as indicated by arrows
62. In the
process, air is drawn through aperture 50 and into the empty interior 54 of
the third
cylindrical member.
As the smoke passes through the empty interior 54 of the third cylindrical
member, it is
cooled due to the loss of heat through the cover 40. This cooling effect is
accentuated by the
ambient air drawn into the interior through aperture 50. This cooling causes
harmful
products in the smoke, such as nicotine, to condense prior to reaching the
filtering medium
24, thereby reducing harmful products in the smoke before it reaches the
smoker's mouth,
throat and lungs.
It should be understood that many of details described above are by way of
example only and
are not intended to limit the scope of the invention which is to be
interpreted with reference
to the following claims.

Dessin représentatif