Note: Descriptions are shown in the official language in which they were submitted.
,. _ CA 02273323 1999-OS-28
1
TITLE
Filter
TECHNICAL FIELD
The present invention relates to a filter for use with
a smoking article for the filtration of secondary smoke.
Also contemplated are smoking articles incorporating such
filter.
BACKGROUND ART
The term "smoke" herein used may encompass visible
smoke, particulate matter in smoke, noxious gases, vapours,
aerosols, or the like, produced by a smoking article.
"Smoking article" may encompas:> a cigarette (including less
smoke cigarettes, coaxial cigarettes and the like), cigar,
simulated smoking article, pipe, or the like. "Rod of
smokable material" may encompass a cigarette, cigar or the
like. "Combustion" may encompass smouldering.
Secondary smoke comprises of smoke that is exhaled by
a smoker and/or sidestream smoke which is emitted into the
ambient environment from the burning portion of a smoking
article. Secondary smoke causes considerable discomfort and
harm to passive smokers. Fast efforts to solve this
problem have not been very successful. The prior art
includes cigarette filter tip:, tubular cigarette holders
with filter elements for filtering mainstream smoke,
sheaths formed from cigarette wrapping materials, coaxial
filter cigarettes, and various; hand held smoke filtration
CA 02273323 1999-OS-28
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devices.
Cigarette filter tips have- been used with a tobacco
column for filtering inhale ~.moke. kith respect to the
filtration of exhale smoke, cigarette filter tips may have
one or more of the following drawbacks:
a) the filter materials used in filter tips allow a
considerable amount of smoke to pass therethrough so
that a smoker may fulfill his desire for smoke. Said
filter materials may not. filter exhale smoke to be
substantially smoke-free.
b) valves provided in some kilter tips may open for the
drawing of inhale smoke and/or ambient air. However
said valves may not substantially check the inflow of
said ambient air through said filter tips upon
inhalation and allow a considerably high rate of
exhale flow therethrough-that may be expected if said
filter tips are to be used to filter exhale smoke.
In addition, the filter materials used in filter tips
have a high resistance to exhale flow, thereby making
exhalation into such materials almost impossible. Further,
ventilation holes or vents provided in filter tips for the
dilution of inhale smoke are too minute in size for
allowing a high rate of exhale flow therethrough that may
be expected if said filter tips are to be used for
filtering exhale smoke. In some cases, filter materiais
are not be provided along the ventilation vents for
filtering smoke.
CA 02273323 1999-OS-28
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AU-H-84618/82, in partic:ular, disclosed a chambered
filter for a cigarette comprising a first longitudinally
extending cylindrical chamber and a second longitudinally
extending cylindrical chamber disposed within the first
chamber. A porous filter rod may be provided in the space
between the walls of the fir:>t and second chambers, said
porous filter rod allows ambient air to be drawn for the
dilution of inhale smoke. An air pervious tipping paper
may be used to circumscribe said porous filter rod. In
this article, it may be noted that (a) the second chamber
has an air~impervious wall whereby smoke exhaled into said
second chamber may not access the filter rod, and (b) the
article does not provide any means for substantially
checking the flow of ambient air through the filter rod
during inhalation. Also, the filter rod may not allow ~~a
considerably high rate of exhale flow therethrough.
US Pat. 4,955,397 disclosed a cigarette having a
filter plug located at one end of said cigarette. Said
filter plug has a cylindrical passageway coaxial
therethrough, said passageway communicates only with the
tobacco rod, whereas said filter plug communicates with a
cylinder of carbon fuel surrounding the tobacco rod and
filters flows from said carbon fuel. However, it may be
noted that this article does not provide any means for
substantially checking the floe of ambient air through the
filter~plug during inhalation, and it may not allow a high
rate of exhale flow therethrouc~h during exhalation.
US Pat. 4,620,553 disclo:~ed a filter for a smoking
CA 02273323 1999-OS-28
r
4
article employing a valve assembly resiliently biased
towards a first open position for allowing the inf low of
ambient air, said valve assembly being displaceable towards
a second closed position to <:ut off ambient air when a
particular suction pressure is exceeded. AU-B-57657/86
disclosed an insert interposed between a tobacco column and
a filter tip. Said insert has a valve member for admitting
ambient air into the inhale flow upon a weak suction,
whereas ambient air is cut off upon a strong suction. In
both articles it may be noted that ( a ) the filter materials
are intended to allow a substantial amount of smoke to pass
through for the purpose of smoking. Such filter materials
may not filter exhale smoke to lbe substantially smoke-free,
and (b) the valve members may riot substantially check the
reverse flow of ambient air through the articles and they
may not allow a high rate of eachale flow therethrough.
Furthermore, the insert of AU-B-57657/86 does not
contain any filter materials :Eor filtering exhale smoke.
Also, it is not stated that the valve member may allow
passage of exhale smoke through said insert.
Tubular cigarette holders. with filter elements have
been used with filter and non filter cigarettes for
filtering mainstream inhale smoke. In use, the mouth end
of a cigarette is attached to one open end of a tubular
cigarette holder wherein filter elements provided in the
cigarette holder may filter any smoke drawn through said
holder. With respect to the :filtration of exhale smoke,
however, such cigarette holders. may have one or more of the
CA 02273323 1999-OS-28
following drawbacks:
a) the filter materials used in cigarette holders allow
a substantial amount of smoke to pass through such as
y is intended to satisfy a smoker's desire for smoking.
Such filter materials may not filter exhale smoke to
be substantially smoke-free.
b) the filter materials used in cigarette holders may
allow for easy inhalation, but such materials are
resistant to the passage of exhale smoke.
c) no provision may be made for the discharge of exhale
flow from a cigarette holder. Once a cigarette is
attached to an open end o~f a holder, said end would be
blocked by said cigarette. When the opposite end of
said holder is inserted into the mouth, it may be
impossible to exhale into said holder and for any
smoke trapped inside said holder to be discharged into
the ambient environment.
US Pat. 4,369,798, in particular, disclosed a
combination cigarette holder and cigarette smoke catcher
comprising a cigarette holder body terminating at one end
in a hollow mouthpiece, said mouthpiece communicates to a
pair of parallel cylindrical ;passages provided within the
holder body. One passage holds the unlit end of a
cigarette while the other passage holds a smoke catcher
cartridge for filtering exhale smoke blown into said
mouthpiece. Said cigarette holder, nevertheless, suffers
from the following drawbacks, (a) the holder body employs
CA 02273323 1999-OS-28
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a valve means in the passage for holding a cigarette, said
valve means is provided for allowing the flow of inhale
smoke. In use however, the action of the valve means
actually impedes the inhale flow and causes an undesireable
increase in resistance to inhalation, (b) the flow of
exhale smoke through the passage holding the cigarette may
be substantially blocked by said cigarette in
communication. Said valve means is therefore not essential
for the performance of the holder body, (c) said valve
means adds to the weight, size, cost and manufacturing
complexity of the cigarette lholder, (d) the passage for
holding the smoke catcher filter opens at the other end to
the exterior of said body remote from the mouthpiece. This
forces exhale flow to travel a long distance through said
passage and through the length. of the smoke catcher filter
cartridge before xeaching the ambient environment. This
has the effect of increasing resistance to exhalation and
adding unnecessarily to the size and weight of the holder
body, (e) the smoke receiving surface of the smoke catcher
filter cartridge is limited by the radial cross-section of
the second passage. A small cross-section may limit the
efficiency of filtration while a large cross-section may
add considerably to the circumference of the holder and
deprive it of elegance, (f) the holder is not disposable in
nature, but employs a replaceable smoke catcher filter
cartridge. Loading and unloading of cigarettes and
cartridges is an inconvenience, (g) the holder is presented
as a stumpy, generally rectangular body. The considerably
CA 02273323 1999-OS-28
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large circumference of then holder body renders it
unsuitable- for packaging into a cigarette box with a
cigarette in communication in a pre-packed form, (h) the
holder body is not coaxially aligned in communication with
a cigarette. It lacks a streamline profile with a
cigarette, which profile may ;be desirable to a discerning
smoker, and ( i ) the holder body comprises of hinged body
halves which require some effort iiz loading and unloading
of cigarettes and filter cartridges.
Further, a number of patents have been filed on
cigarette wrapping materials. Wrapping materials are used
to circumscribe a rod of smokable material. Some wrappers
may be fire resistant with rs~spect to preventing the lit
tobacco materials from igniting objects coming into contact
with the cigarette. In some cigarettes, more than one
layer of wrapping materials may be used. Sheaths formed
from such wrapping materials may have one or more of the
following drawbacks:
a) they may lack a filtering capability for substantially
filtering smoke before release into the ambient
environment.
b) they may lack porosity t:o ambient air necessary for
the sustenance of combustion of the smokable materials
therein contained.
c) they may be significantly impaired or destroyed by the
combustion of the smokable materials therein
contained.
CA 02273323 1999-OS-28
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AU-A=76346/91 disclosed a method of producing a non-
burning wrapper for use with smoking products. US Pat.
3,220,418 and US Pat. 3,886.954 disclosed cigarettes having
an essentially non-combustible sheath which retains ashes
and shields the burning zone of a cigarette. These prior
arts, however, lack a filtration capability for sidestream
smoke filtration.
A number of coaxial filter cigarettes have been
proposed which may resemble a sheath laid over a rod of
smokable material. These cigarettes may have one or more
~of the following drawbacks:
a) the sheath may not have <~ filtration capability,
b) the sheath may lack t:he porosity necessary for
combustion sustenance, and
c) the sheath may be significantly impaired or destroyed
by combustion of the smokable materials therein
contained.
AU-B-48501/90, in particular, disclosed a coaxial
filter cigarette having an inner core of tobacco material,
a wrapper surrounding the inner core, an outer shell of a
tobacco and/or non-tobacco material coaxially surrounding
the inner core and its wrapper, and an outer wrapper
surrounding the outer shell <~s well as a filter portion
which substantially reduces the smoke particles originating
from the inner core whereas the aerosol produced in the
outer shell is only slightly or not influenced at all by
the filter portion. The article of AU-B-48501/90 lnay
CA 02273323 1999-OS-28
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reduce sidestream smoke emission through shielding by the
outer shell. However, it may .be noted that (a) neither the
outer shell nor the outer wrapper is specifically mentioned
to contain any filter material. On the contrary, the outer
shell comprises of materials intended for releasing aerosol
and/or vapour for smoking, (b) the outer shell is
significantly permeable to sidestream smoke and allows the
generated smoke to pass through and be inhaled as
mainstream smoke, and (c) the article uses a cigarette
paper as an outer wrapper for surrounding the outer shell,
said cigarette paper is either air impermeable or has a
very low air permeability of less that 25 ISO units. Such
low air permeability may not allow for sustenence of
combustion of the tobacco materials contained therein
unless said outer wrapper is s:ignif icantly destroyed during
the combustion process.
Various accessory smoke :filtration devices have been
proposed. US Pat. 4,685,47i', for example, described a
protective filter sheath for surrounding a cigarette. In
this article, the filter wall is not overlaid on a
cigarette, but is substantially spaced from a cigarette by
an air space. The article may thus considerably increase
the circumferential thickness to be handled by a smoker by
virtue of the space provided between the cigarette and the
filter wall.
US Pat. 5,495,859 disclosed a tubular filter for use
in a smoker's accessory for filtering cigarette smoke.
Said filter has an inlet end for directing sidestream smoke
CA 02273323 1999-OS-28
or exhale smoke into an end of an inner elongate chamber
within said tubular filter. In this article, it may be
noted that said tubular filter may not overlay a cigarette.
On the contrary, sidestream smoke is generated outside the
elongate chamber and is directed into said inner elongate
chamber for filtration.
None of the prior arts have been greatly successful in
the market place. Smokers' preference is complex and their
rejection of various drawbacks of the prior art may be
central to commercial failcEre. Secondary smoke thus
continues to affect an innumerable number of non-smokers
daily. This invention therefore attempts to provide a
better solution to the problem of secondary smoke
pollution, if it is possible, that various drawbacks of the
prior arts elaborated above m<~y be eliminated or lessened.
SUMMARY OF INVENTION
According to a first aspeact of the present invention,
a filter sleeve for filtering exhale smoke comprises a
sleeve having a downstream portion arranged for
communicating with a smoking article to receive inhale
smoke from the smoking article, an upstream portion
arranged for inhalation of the inhale smoke and for
receiving of exhale smoke, at least one inhalation flow
path from the downstream portion to the upstream portion,
the inhalation flow path being provided for channelling the
inhale smoke for inhalation through the upstream portion,
at least one exhalation flow path extending from the
CA 02273323 1999-OS-28
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upstream portion to at least: one exit to the ambient
.environment whereby exhale smote;e received into the upstream
portion is channelled through 'the exhalation flow path for
filtration and discharge of filtered air into the ambient
environment, filter means provided along at least one
exhalation flow path, the filter means being provided for
filtration of received exhale smoke to produce filtered
air, the filter means being of such efficiency as to render
the filtered air substantially smoke-free, wherein the
discharge of the filtered air :into the ambient environment
is significantly unimpeded by the smoking article when the
smoking article is in flow communication with the
downstream portion of the sleeve, and means for
substantially checking the reverse flow of ambient air
through the exhalation flow path, the means allowing a
- considerably high rate of exhale flow to pass through the
exhalation flow path.
According to a second aspect of the present invention,
a filter sheath for filtering s~idestream smoke comprises a
sheath arranged for overlaying a significant expanse of the
sidestream smoke emission areas of a rod of smokable
material, the sheath consists significantly of a filter
material that is substantially impermeable to sidestream
smoke, the sheath is of sufficient porosity to air to
enable sustenance of combustion of the rod of smokable
material and being significantly unimpaired by the
combustion of the rod of smokable material.
In its most essential form, the filter sleeve and
CA 02273323 1999-OS-28
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filter sheath may be similar i:n that the sleeve and sheath
both have a slim body having an. elongated hollow and filter
means provided along the flaw path of secondary smoke
through the slim body. The difference in the way the
filter sleeve and filter sheath relate to a smoking article
reflects the different ways the same essential form may be
applied to the two different aspects of secondary smoke,
namely exhale smoke and sidesi=ream smoke. If instead of
the filter sleeve, the most essential form of the filter
sheath is Joined in end to end communication with the
. mouth-end of a cigarette, the sheath will also be able to
filter exhale smoke. Various other features of the filter
sleeve are provided for the purpose of enhancing the
performance of the sleeve so that it may meet the minimum
level of expectation of smokers. The particular manner in
which the filter sleeve and fi:Lter sheath are arranged for
relating to a smoking article, gives the present invention
numerous advantages over the prior art.
The possible advantages of the invention include (a)
enhanced slimness of the filter, (b) reduced weight, (c)
the provision of a disposable i_ilter in communication with
a cigarette or cigar, (d) easy and economic packaging, and
(e) zero maintenance. Other possible advantages of the
filter sleeve and filter sheai:h will be readily apparent
from the descriptions, details, examples, drawing and
claims. below.
The filter sleeve may be used with a smoking article
such as a cigarette (encompasses conventional cigarettes,
CA 02273323 1999-OS-28
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less smoke cigarettes, coaxial cigarettes, and the like),
cigar, simulated smoking article, pipe, or the like.
At least one downstream inlet may be provided at the
downstream portion of the sleeve:, said downstream inlet may
be provided for the receiving of inhale smoke into the
inhalation flow path. Said downstream inlet may be
provided in the downstream end of the sleeve and/or in the
wall of the sleeve toward the downstream ernl. When the
downstream inlet of the sleeve is in flow communication
with a smoking article, smoke from said smoking article may
be drawn into said downstream inlet, move along the
inhalation flow path, and out through the upstream portion
of said sleeve for inhalation.
The upstream portion may receive exhale smoke at a
Considerably high rate of exhale flow.
At least one upstream oui~let may be provided at the
upstream portion of the sleeve, whereby inhale smoke
channelled through the inhalation flow path may be inhaled
through said upstream outlet. The upstream outlet may be
provided in the upstream end ~of the sleeve and/or in the
wall of the sleeve toward the upstream end.
At least one upstream inlet may be provided at the
upstream portion of the sleeve, said upstream inlet may be
provided for the receiving of exhale smoke into said
upstream portion and the exhalation flow path. The
upstream inlet may be provided in the upstream end of the
sleeve and/or in the wall of the sleeve toward the upstream
end. The upstream inlet may a:Llow a considerably high rate
CA 02273323 1999-OS-28
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of exhale flow to pass therethrough. Said upstream inlet
may preferably provide a total opening size of at least 4
sq. mm. for receiving exhale e;moke.
At least one upstream outlet may be provided at the
upstream portion of the sleeve for the inhalation through
said upstream outlet of inhale smoke channelled through
said inhalation f low path, andi at least one upstream inlet
may be provided at the upstream portion for the receiving
of exhale smoke into said upstream portion and into the
exhalation flow path, whereby said upstream outlet and said
upstream inlet may coincide. The upstream outlet-cum-inlet
may allow a smoker to inhalE: from and exhale into the
sleeve without any adjustment of the sleeve.
At least one inhalation f:Low path may connect at least
one downstream inlet to at lea:at one upstream outlet of the
sleeve. In one example, the inhalation -flow path may be
defined by the elongate hollo~r inside the sleeve.
The exhalation flow path may exit the sleeve through
the sleeve wall.
The exhalation flow path iaay allow a considerably high
rate of exhale flow to pass the:rethrough so that exhalation
into and through said exhalation flow path may be made
easy. In one embodiment, the exhalation flow path may be
defined by the elongate hollow inside the sleeve wherein
exhale smoke may flow longitudinally along said hollow and
exit the sleeve through the sleeve wall (side-wall) and/or
openings in the peripheral regions of the downstream end of
said sleeve.
..,.,.".....,M.._~._..,_. CA 02273323 1999-05-28
The inhalation flow_path and the exhalation flow path
may coincide in part or in whole. In one example, a part
of the exhalation flow path may coincide with a part of the
inhalation flow path. Figure 2 below shows one embodiment
of such an example. In a second example, a part of the
exhalation flow path may coincide with the whole of the
inhalation flow path. This will become obvious from the
description of Figure 4 below. I'n a third example, the
whole of the exhalation flow path may coincide with the
whole of the inhalation flow path, as when the sleeve wall
is made of porous activated carbon paper wherein a thin
plastic film may be laid over said porous activated carbon
paper. Said plastic film may be punched to achieve
apertures and flaps, said flaps may move outwardly away
from the sleeve to open .>aid apertures. When the
downstream end of the sleeve is in communication with a
smoking article, exhale smoke blown into the upstream open
end of the sleeve may move along wthe elongate hollow of
said sleeve whereby the flaps may open to allow exhale flow
to exit the sleeve through said apertures. When suction is
applied on the upstream open end of the sleeve, the flaps
may close and inhale flow may move through said same
elongate hollow. In one embodiment, the porous activated
carbon paper may overlay an inner sleeve made of thin film,
said inner sleeve may have apertures corresponding to the
apertures and flaps of the outer plastic film whereby
inhale smoke flowing along t:he elongate hollow of said
inner sleeve may be substantially insulated from the porous
CA 02273323 1999-OS-28
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activated carbon paper so that the taste of said inhale
smoke may not be significani:ly affected by said porous
activated carbon paper. The use of substantially the whole
space of the elongate hol7low of the sleeve reduces
resistance to inhalation and exhalation, thereby making
this embodiment suitable for use with a rod of smokable
material having a relatively :mall external circumference.
The filter means may comprise of filter materials
embodied in at least a portion of the wall of the sleeve
wherein exhale smoke channelled through the exhalation flow
path may be filtered transversely through said filter
materials. Encompassed are :Filter materials embodied in
the wall of at least one exhalation flow path.
In one example, a filter sleeve may be adapted for use
with a rod of smokable mate:rial having a large radial
cross-section such as a cigar or a tobacco pipe wherein the
filter means of the sleeve m<~y comprise of a filter plug
held inside an exhalation flow path of the sleeve, said
filter plug may be of sufficient radial cross-section and
low resistance to exhale flow whereby said sleeve may have
a low resistance to exhalation.
The filter means be of ;such efficiency as to render
the filtered air substantial7ly smoke-free so that nearby
non-smoking persons may enjoy a substantially smoke-free
environment.
The filter means may allow a considerably high rate of
exhale flow to pass therethrough. This may be achieved,
for example, by employing a filter material with a low
CA 02273323 1999-OS-28
17
resistance to exhalation or by providing a large smoke
receiving and filtration surface and/or a short distance of
travel through the filter maiterial, as for example, when
the exhale smoke is channelled transversely through a
porous filter material forming a substantial portion of a
reasonably thin sleeve wall.
The filter means may be practically non-replaceable.
For example, it may not employ a replaceable filter
cartridge or any filter material that may be selectively
replaced while continuing the use of other parts of the
sleeve for their intended purposes. In one embodiment, a
sleeve with a non-replaceable filter component may be
provided integrally with a cigarette or cigar whereby said
sleeve together with its f ilt:er component may suitably be
discarded after consumption oi: said cigarette or cigar. In
another embodiment, a filter sleeve may be provided
separately whereby a smoker may personally attach said
filter sleeve to a smoking article. Such a sleeve may
employ a long-lasting non-replaceable filter component
whereby said filter sleeve may be used to filter one or
more smoking articles before said filter sleeve together
with its filter component is discarded.
The filter means may comprise of at least one layer of
filter materials. In one example, the filter means may
comprise of one layer for filtering particulate matter and
another layer f or f i ltering gaseous components . The f i lter
materials may be embodied in a porous host material such as
a polymeric or ceramic or composite material. In one
CA 02273323 1999-OS-28
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embodiment,- the ffilter means may comprise of activated
carbon porous paper or fabric forming the wall of the
sleeve, which material may be easily bio-degradable.
The filter means may comprise any filter medium or
combination of filter materials that may significantly
filter secondary smoke. Encompassed are adsorbents for
physical adsorption wherein exhale smoke may be bonded to
the filter material by intermolecular attraction. Examples
of adsorbents include forms send combinations of Fuller's
earths, activated clays, bauxite, alumina, bone char,
decolorizing carbons, gas-adsorbent carbon, molecular-
screening activated carbon, synthetic polymeric adsorbents,
silica gel, or molecular sieves. Some prior art on
suitable activated carbon filter materials are disclosed in
a later part of this section.
Also encompassed are additives for chemisorption of
exhale smoke wherein said exhale smoke may interact
chemically with said additives. Sorption methods taught in
the various prior arts on si.destream reducing cigarette
wrapping materials and accessory smoke filtration devices
may be adapted in the filter sleeve of the present
invention.
In another example, the filter means may comprise of
at least one electrically charge/discharge ion exchange
medium.
The sleeve may include an outer wrapper, preferably
air permeable, which may be useful to conceal the filter
materials used, prevent the ~3ropping of black dust from
CA 02273323 1999-OS-28
19
activated carbon materials, or improve the appearance and
feel of the article.
Discharge of filtered air into the ambient environment
may be provided through the wall of the sleeve and/or
through the downstream end of the sleeve. In one
embodiment, the filter means may comprise of filter
materials embodied in the wall of the sleeve. When the
downstream end of the sleeve is substantially blocked by a
smoking article in communication with said downstream end,
exhale smoke blown into the upstream end of the sleeve may
move along the elongate. hollow of the sleeve and be
filtered transversely through t:he filter materials embodied
in the wall of the sleeve whereby the resulting filtered
air is discharged directly into the ambient environment.
In another embodiment, an inner sleeve may be provided
substantially coaxially inside an otter sleeve, said inner
sleeve has a closed downstream. end. A smoking article may
be engaged to the downstream end in flow communication with
the outer sleeve. Filter materials disposed within the
inner sleeve produces filtered air when exhale smoke is
blown into the upstream open end of said inner sleeve,
wherein said filtered air mast be discharged via tubular
protruberances connecting a downstream section of said
inner sleeve to openings in the wall of the outer sleeve.
-In a third embodiment, longitudinal grooves provided on the
inside wall of a downstream portion of a sleeve may be
transformed into exhalation flew paths for the discharge of
filtered air when a smoking article is inserted into and
CA 02273323 1999-OS-28
held within said downstream portion of the sleeve.
The means for substantially checking the reverse flow
of ambient air through the exhalation flow path may totally
stop the reverse flow of ambient air through said
exhalation flow path or allow some or a predetermined
amount of ambient air to f low ithrough said exhalation f low
path for the dilution of inhale smoke. In one embodiment,
an inhalation f low path and an exhalation flow path may
both be in flow communication with an upstream opening of
the sleeve, wherein a valve assembly provided along said
exhalation flow path may allow a predetermined amount of
ambient air to pass through said exhalation flow path so
that inhale smoke flowing through said inhalation flow path
may be diluted before reaching' the mouth of a smoker.
The means for substantially checking the reverse f lo'ta
of ambient air through the exhalation flow path may
comprise of a valve system provided along said exhalation
flow path.
The means for substantially checking the reverse flow
of ambient air through the exhalation flow path may
comprise of a valve system oprovided outside the sleeve
wherein said valve system may be adapted for cooperating
with said exhalation flow path for substantially checking
the reverse flow of ambient air through said exhalation
flow path. For example, a valve assembly may be provided
along.a through-way within a tobacco column, filter tip or
an insert, said valve assembly may be connected in flow
communication with the exhalation flow path of the filter
CA 02273323 1999-OS-28
21
sleeve when said tobacco column, filter tip or insert is in
communication with the downstream portion of the filter
sleeve.
In one example, the valve assembly for use as the
means for substantially checking the reverse flow of
ambient air through the exhalation flow path may be adapted
from an existing valve system. The movable valve member
may be resiliently biased towards a closed position or
close through ionic or electrostatic attraction, magnetic
attraction, or pneumatic pre:asure. Where desirable, at
least one movable valve member may be adapted to close
incompletely so that a certain amount of ambient air may be
permitted to enter the sleeve through said valve system for
dilution of the inhale smoke when the sleeve is in flow
communication with a smoking article. In addition or
alternatively, holes may be provided in one or more of the
valve members or wall of the sleeve or downstream end of
the sleeve for introducing ambient air into the inhale flow
so that the inhale smoke may be diluted. The sizes and
quantity of said holes may be such as to disallow too much
unfiltered exhale flows to escape into the ambient
environment. Preferably, said holes may be provided
downstream of a valve system provided along the inhalation
flow path for checking exhale flow so that exhale smoke may
not exit the sleeve through said holes. The holes may be
distributed in any conventional manner at the preferred
regions of the sleeve.
In one example, said means for substantially checking
CA 02273323 1999-OS-28
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the reverse flow of ambient air through the exhalation flow
path may reside in the special construction of. the upstream
portion of the sleeve whereby an upstream outlet in
communication with an inhalation flow path may be
sufficiently distinguished from an upstream inlet in
communication with an exhalation flow path so that said
upstream outlet may be drawn without substantially drawing
on said upstream inlet. In one embodiment, the upstream
portion of the sleeve may comprise of an inner tube
provided coaxially within an outer tube so that the
upstream end of the inner tube protrudes out of the
upstream end of the outer tube. The elongate hollow of the
inner tube may then define an inhalation flow path for
(drawing inhale smoke. The space between the outside wail
of the inner tube and the insidie wall of the outer tube mad
then define an exhalation flow path for channelling exhale
flow. In use, a smoker may close his lips on the
protruding upstream open end of the inner tube to draw
inhale smoke, and then adjusi~ his lips to close on the
shorter outer tube to exhale smoke back into the filter
sleeve for filtration. Exhale smoke may not substantially
enter the inhalation f low path since such a route may be
substantially blocked by the :Filter tip or tobacco column
of a smoking article in communication.
The upstream portion through the upstream inlet, the
exhalation flow path, the filter means and the means for
checking the reverse flow of ambient air through said
exhalation flow path, may allow a considerably high rate of
CA 02273323 1999-OS-28
23
exhale flow to pass therethrough whereby a smoker may
exhale with considerable ease into and through the ffilter
sleeve. In addition, it may minimize the pressure of any
reverse flow of exhale smoke through the inhalation flow
path so that said reverse flow may be sufficiently blocked
by a smoking article in communication with the downstream
portion of said ffilter sleeve.
It is preferable that the sleeve be suitably rigid to
allow for more robust handling. Where the wall of the
sleeve lacks rigidity, rigid support may be provided, for
example, through a supporting layer, mesh, ribs or the
like.
A filter plug for filtering 'inhale smoke may be
provided along the inhalation flow path. Said filter plug
may be provided as a supplement or substitute for the
filter tip of a smoking article or as an addition when the
filter sleeve is to be used with a non-filter smoking
article.
The filter means may comprise of filter materials
embodied in at least a portion of the sleeve wall or in the
wall of at least one exhalation flow path, and a valve
assembly may be provided alone the inhalation flow path or
outside the sleeve, said valve' assembly may be adapted for
cooperating with said inhalation flow path to allow inhale
smoke to pass through said inhalation flow path but
substantially prevent exhale flow from passing through said
inhalation flow path. In one embodiment, a valve assembly
may be provided along a through-way within a tobacco
CA 02273323 1999-OS-28
.,
r
24
column, filter tip or an insert whereby said valve assembly
may be connected in flow communication with the-inhalation
flow path of the filter sleeve when said tobacco column,
filter tip or insert is in communication with the
downstream portion of the filiter sleeve.
Additionally or alternatively, a double action valve
assembly may be adapted for oppositely opening and closing
the inhalation flow path and exhalation flow path of the
sleeve to determine the direction and desired mix of fluid
flow therethrough.
The sleeve may have an external circumference not
significantly larger than that of the rod of a smoking
article. The rod of a smoking article may encompass the
stem of a tobacco pipe. Preferably, the external
circumference of the sleeve may be the same or similar to
that of the rod of a smoking article so that the sleeve in
communication with said smoking article may provide a
streamline profile and appear as a natural extension of
said smoking article. Used with a smoking article having
a rod of large external circumference, the sleeve may
appropriately have a smaller external circumference or
taper toward the mouth-end. The sleeve may be of any
reasonable cross-sectional shape.
The filter sleeve may be adapted for substantial
coaxial alignment in communication with the rod of a
smoking article. When provided in communication, the
respective communicating portions of the filter sleeve and
the smoking article may be circumscribed with wrapping
CA 02273323 1999-OS-28
25
material.
Flow communication between the filter sleeve and a
smoking article may be achieved in any manner. In one
embodiment, flow communication between the downstream
portion of the sleeve and t:he smoking article may be
provided through a tubular intermediary linking said
downstream portion of the sleeve to the mainstream smoke
outlet of said smoking article. In another embodiment, the
mouth end of a cigarette may abut or mate into the
downstream inlet of the filter sleeve.
The upstream portion of the sleeve may be
circumscribed with wrapping material and/or tipping
material. Said wrapping material and/or tipping material
may be air permeable or air imperineable in any conventional
manner. Preferably the wrapping material and/or tipping
material may not cover any up:>tream outlet or inlet.
A whistle may be incorpc>rated or provided along the
exhalation flow path so that a smoker may gauge the
condition of his lungs from the sound of the whistle.
The filter sleeve may incorporate any combination of
features described above.
The filter sleeve may incorporate any one or more in
combination of the features elaborated above wherein the
downstream portion of the sleeve may be provided in flow
communication with the mainstream smoke outlet of a smoking
article whereby one or more of such filter sleeve with a
smoking article may be in a pre-packed form. Such a pre-
packed form may relieve a smoker of the task of connecting
CA 02273323 1999-OS-28
26
a smoking article to a filter sleeve.
The filter sheath of the present invention may be used
with a rod of smokable material such as a cigarette
(encompasses less smoke cigarettes and coaxial cigarettes),
cigar, simulated smoking article, or the like.
The sheath may be adapted for overlaying a significant
expanse of the sidestream smoke emission areas of a rod of
smokable material. This may encompass a sheath adapted for
overlaying all of the sidestre~am smoke emission areas of a
rod of smokable material. In a conventional cigarette or
cigar, the combustible surfaces of the cigarette or cigar
may constitute the sidestream smoke emission areas of said
cigarette or cigar. With a rod of smokable material which
has an unlevel external surface about its sidestream smoke
emission areas (such as a cigarette or cigar circumscribet3
with a pimpled wrapping paper), the sheath may overlay the
higher surfaces of said side,stream smoke emission areas
whereby the lower surfaces may be significantly confined by
said sheath so that sidestream smoke emitted through said
lower surfaces may still be substantially filtered through
said sheath. Preferably, .a smoker may not need to
intermitently adjust the shs:ath during the process of
smoking.
A significant portion or even the whole of the sheath
may be made of a filter material. The filter material may
comprise of a filter medium or combination of filter
materials that may significantly filter secondary smoke.
Encompassed are adsorbents for physical adsorption wherein
CA 02273323 1999-OS-28
27
sidestream smoke may be bonded to the filter material by
inter~aolecular attraction. Examples of adsorbents include
forms and combinations of Fulle:r's earths, activated clays,
bauxite, alumina, bone char, decolorizing carbons, gas-
adsorbent carbon, molecular-:>creening activated carbon,
synthetic polymeric adsorbents, silica gel, or molecular
sieves. In one embodiment,, the filter material may
comprise significantly of activated carbon.
Also encompassed are filter materials comprising
additives for chemisorption wherein sidestream smoke may
interact chemically with said additives. Sorption methods
taught in the various prior arts on sidestream reducing
cigarette wrapping materials and accessory smoke filtration
devices may be adapted in the filter sheath of the present
invention.
The filter material may be embodied in or bonded to a
host material of the sheath which may be a polymeric,
ceramic or composite material. In one example, the sheath
may be formed of activated carbon porous paper or fabric,
which may be light in weight, easy to dispose after use,
and is easily bio-degradable. Some prior arts on suitable
activated carbon filter materials are disclosed in a later
part of this section.
The sheath may comprise of at least one layer of
materials. In one embodiment, the filter material may be
embodied in a single layer of the sheath wall. In another
embodiment, the sheath may comprise of an inner layer for
filtering particulate matter and an outer layer for
CA 02273323 1999-OS-28
28
filtering gas components of sidestream smoke. Such a
sheath may also capture vapour in any- or both the layers.
In a third embodiment, the sheath may include a porous
outer wrapper, possibly of paper, which may be useful,
amongst other functions, to conceal the filter materials
used, prevent the dropping of black dust if certain forms
of activated carbon materials are used, and to improve the
appearance, feel and/or filtration capabilities of the
sheath.
The sheath may be of sufficient porosity to air to
enable sustenance of combustion of a rod of smokable
material when said rod of smok:able material is accordingly
held within said sheath. In one embodiment, the sheath may
be porous or air permeable. In another embodiment, the
sheath may be provided with perforations in its wall to
allow ambient air to pass therefhrough for combustion
sustenance. In a third embodiment, the sheath may contain
a combustible filler material, said filler material may
render said sheath impermeable or of low permeability to
ambient air, said porosity for combustion sustenance may be
attained through a process whereby combustion of a portion
of a rod of smokable material contained within the sheath
destroys a corresponding port=ion of the filler material
thereby rendering the corresponding sheath portion porous
for sustaining the combustion of a further portion of said
rod of smokable material. Once a rod of smokable material
within the sheath is lit and an initial portion of the
filler material is destroyed in the initial combustion, the
CA 02273323 1999-OS-28
29
sheath may attain porosity nE~cessary for sustaining the
combustion of a further portion said rod of smokable
material. Said combustion of said rod of smokable material
may destroy further portions oi: the filler material so that
porosity may be attained for further sustenance of
combustion. The process may continue until substantially
all of the rod of smokable mai:erial may be consumed. The
sheath body may remain substantially unimpaired. The
porosity of the sheath may also allow for diffusion of heat
through the sheath material into the ambient environment.
The sheath may be adapted to suit a rod of smokable
material so that the required draw resistance, smoke
quality and quantity, taste, lburn characteristics, number
of puf f s , and so on, may be achieved .
The sheath may be significantly unimpaired by the
combustion of a rod of smokable material when the rod of
smokable material is accordingly overlaid within said
sheath. This feature makes possible significant
confinement of combustion products and its proper
filtration through the wall of the sheath. A wholesome
sheath may provide visual evidence of confinement and thus
impart psychological comfort to both smokers and non-
smokers. This feature may also allow the sheath to look
good and be held in the hand after the smokable materials
have been consumed. Such a sheath may also present a
convenient outer surface fox- carrying health warnings,
product information, brand captions and the like. In one
embodi ment, the sheath may be :>ubstantially non-combustible
CA 02273323 1999-OS-28
at the temperature of a lit cigarette or cigar, or even at
higher temperatures. In anothear embodiment, the sheath may
include an outer filter layer and an inner layer for
supporting a rod of smoka~le m<~terial. The inner layer may
be a flame protection layer which may be non-combustible or
flame resistant or heat reducing. In one example, the
inner layer may comprise of a mesh, ribs, pimples, or the
like. In a variation, a non-combustible, flame resistant
or heat reducing support may be provided over a rod of
smokable material, said support together with the rod of
smokable material may then be loaded into an outer filter
layer of the sheath.
The filter sheath may be :suitably rigid so that it may
not sag after the smokable materials contained therein have
been exhausted in the smoking process. Such rigidity may
also allow for a more robust handling of the article.
Rigidity may be achieved by making said sheath of a
suitably rigid material or by providing a rigid support
such as a laminating layer, mesh, ribs or the like.
Rigidity may also provide scope for modification of the
shape of the article. Suitable modifications of shape may
include the flattening of some external surfaces to retard
the tendency of the sheath to roll off a slanted surface.
A single sufficiently air permeable, non-combustible,
suitably rigid filter layer is a preferred material for
making the sheath. Such a layer may be provided in the
form of a sheet, membrane, skin or film.
A cigarette or cigar may normally be circumscribed
CA 02273323 1999-OS-28
31
with a wrapper, said wrapper performing a first function of
holding together the smokable materials, and a second
function of ensuring that ambient air is substantially
drawn through the burning end of said rod of smokable
material. It may be noted that the filter sheath of the
present invention may also hold the smokable materials
together. Thus, when a cigarette, cigar or other similar
smoking article is to be used with the filter sheath of the
present invention, said cigareate, cigar or other similar
smoking article may be provided with or without a
circumscribing-wrapper.
The sheath may have a mouth-side downstream end with
respect to the direction of flow of the inhale smoke.
Various adaptations may be made to facilitate the loading
of smokable material into the sheath. In one example, the
- sheath may have a downstream open end through which a rod
of smokable material may be l~oaded~ In a second example,
the sheath may have an upstream open end through which a
rod of smokable material may be loaded and/or ignited. In
a third example, the sheath may be formed by wrapping the
sheath material over a rod of smokable material. In a
fourth example, the inside of the sheath may be lined with
a wrapper. Smokable materials may subsequently be loaded
into said wrapper.
The sheath may have an orifice for allowing ignition
of a rod of smokable material to be therein contained.
Preferably said orifice may be: provided to correspond with
the upstream portion of said rod of smokable material.
CA 02273323 1999-OS-28
32
Said orifice may be provided with a door which may be
closed after the smokable material in the sheath has been
lit. Suitable doors may include a flap door, a sliding
door, a swing door, a detachab:Le cap, a slidable overlying
sleeve, or the like.
In one embodiment, the sheath may have a lighting
surface adapted for allowing a flame or heat source placed
near or on said lighting surface to ignite a rod of
smokable material contained within the sheath. Said
lighting surface may be made o:f a non-combustible or flame
resistant material The lighting surface may suitably be
provided at the upstream end portion of the sheath. It is
also preferable that the lighting surface be provided with
a smoke filtration capability ao that any sidestream smoke
passing through said lighting surface may also be filtered
- before release into the surroundings. Said smoke
filtration capability may reside in the non-combustible or
flame resistant material or in another material cooperating
with said non-combustible or fl-ame resistant material. The
lighting surface may allow a :>moker to light up a smoking
article contained within a filter sheath without having to
bother about opening or closing an ignition opening. The
lighting surface may hold in the ashes generated by the
burning of smokable materials. Suitable materials for
making the lighting surface include a non-combustible or
flame resistant fabric, paper, metalic, plastic or ceramic
mesh, adapted to have pores of sufficient size and/or heat
conductivity to allow smokable materials held within the
CA 02273323 1999-OS-28
33
upstream end of the sheath to be ignited.
The portion about the downstream end of the filter
sheath may be circumscribed with tipping paper.
The sheath may be provided with at least one
transparent or translucent portion for allowing a smoker to
view a rod of smokable material therein contained so that
the stage of consumption of said rod of smokable material
may be known.
The filter sheath according to any one or more in
combination of the features elaborated above may overlay a
rod of smokable material such that the mainstream smoke
outlet of said rod of smokable material may correspond with
an open end of said sheath, whereby one or more of such
filter sheath overlaying a rod of smokable material may be
provided in a pre-packed form. Such a filter sheath with
a rod of smokable material in a pre-packed form may easily
be prepared in large quantities in a mass-production
operation and may relieve users of the need for personal
intervention to load a rod of smokable material into a
filter sheath.
The filter sheath according to any one or more in
combination of the features elaborated above, and the
filter sleeve according to any one or more in combination
of the features elaborated above, may be provided together
wherein one open end of said sheath may be in flow
communication with the downstream portion of said ffilter
sleeve. Preferably said filter sheath and filter sleeve
are of similar circumfere~ntial dimensions and be
CA 02273323 1999-OS-28
34
substantially coaxially aligned in flow communication.
A comprehensive filter smoking article may comprise of
a filter sheath according to any one or more in combination
of the features elaborated above and a filter sleeve
according to any one or more in combination of the features
elaborated above, wherein said.filter sheath may overlay a
rod of smokable material whereby the mainstream smoke
outlet of said rod of smokab~le material may be in flow
communication with the downstream portion of said filter
sleeve. One or more of such comprehensive filter smoking
article may be provided in a pre-packed form.
The filter sleeve may communicate with the rod of
smokable material and/or filter sheath in any conventional
manner. A wrapper may circumscribe the portion about the
joint of the filter sleeve with said rod of smokable
material or filter sheath. Said wrapper may indicate a
convenient place for a smoker to hold the article in the
act of smoking. In one embodiment, the filter sheath and
filter sleeve may be of similar circumferential dimensions
and coaxially aligned in communication.
The comprehensive filter amoking article may easily be
made in large quantities in a mass production operation.
The dimensions and shape of a comprehensive filter smoking
article may be adapted to suit a rod of smoking material.
Used with a cigarette, for example, a comprehensive filter
article may have a total length of about 122 mm, external
diameter of about 8 mm, and an upstream inhalation-
exhalation port of about 5 mm diameter, making it extremely
CA 02273323 1999-OS-28
easy to blow into. With such dimensions, the article may
somewhat resemble a conventional ball-point pen without its
cover and cone tip.
DETAILED DESCRIPTION OF THE INVENTION
In order that the present invention may be more
readily understood, the following descriptions are given,
by way of example, of seven specific embodiments made in
accordance with the present invention. These embodiments
are set forth for purposes of illustration only and are not
to be construed as limitations on the present invention.
Numerous combinations of technical features, modifications,
additions and deletions may be made without departure from
the spirit and scope of this invention.
Reference will be made to the accompanying drawings i~n
- which:
Figure 1 is an elongated sectional view of one
embodiment of a filter sleeve for filtering exhale
smoke according to this invention. Figure 1A is a
three dimensional outlinE~ view.
Figure 2 is an elongatect sectional view of a second
embodiment of a filter sleeve according to this
invention. Figure 2A is a three dimensional outline
view.
Figure 3 is an elongated sectional view of a third
embodiment of a filter sleeve according to this
invention. Figure 3A is a three dimensional outline
view.
CA 02273323 1999-OS-28
36
Figure 4 is an elongated sectional view of one
embodiment of a filter sleeve with a smoking article
in a pre-packed form according to this invention.
Figure 5 is an elongated sectional view of one y
embodiment of a filter sheath according to this
invention.
Figure 6 is an elongaited sectional view of one
embodiment of a filter sheath;, with a rod of smokable
material in a pre-packed form according to this
invention. Figure 6A is a three dimensional outline
view of the orifice and sliding door of said filter
sheath.
Figure 7 is an elongai~ed sectional view of one
embodiment of a comprehensive filter smoking article
according to this invention.
Figure 1 is an elongated sectional view of one
embodiment of a filter sleeve for filtering exhale smoke
according to this invention. Figure lA is a three
dimensional outline view of said filter sleeve. The filter
sleeve (1) comprises of a cylindrical sleeve (10), its
elongate hollow closed toward 'the downstream end and at the
upstream end by transverse wa:Lls (19a, 19b), preserving a
slight protrusion (10a} of the sleeve (10) at the
downstream end. Inlets (1'7) are provided along the
periphery of the downstream transverse wall (19a) for
receiving inhale smoke from a E~moking article. Said inlets
(17} are connected in flow communication to outlets (18a)
CA 02273323 1999-OS-28
37
provided along the periphery of the upstream transverse
wall (19b) by a plurality of tubular inhalation flow paths
(13), said inhalation flow paths (13) run longitudinally
inside the elongate hollow of i:he sleeve (10). In addition
to channelling inhale smoke, said inhalation flow paths
( 13 ) may also provide support for the wall of the sleeve
(10). An upstream inlet (18b) is provided in the centre of
the upstream transverse wall (19b~ for receiving exhale
smoke, wherein said exhale smoke may flow along an
exhalation flow path (i4) defined by the elongate hollow of
the sleeve (10), said exhale smoke may be filtered through
filter materials (15) embodied in the wall of the sleeve
(10). Filtered air is discharged from said filter
materials (15) directly into the ambient environment. A
one-way valve (16) is provided along the exhalation flow
path (14) immediately downstream of the upstream inlet
(18b), said one-Way valve (16) is for checking the flow of
ambient air into and through t:he exhalation flow path (14)
when the upstream portion (12) of the sleeve (10) is
inhaled. Said one-way valve (16) is held inside the
exhalation flow path (14) by the upstream transverse wall
(19b). Said valve (16) may be adapted from an existing
valve system.
Figure 2 is an elongated sectional view of a second
embodiment of a filter sleeve according to this invention.
Figure 2A is a three dimen::ional outline view of said
filter sleeve. The filter sleeve (1) comprises of an inner
sleeve (lOb) fitted coaxially into the elongate hollow of
CA 02273323 1999-OS-28
38
a longer outer sleeve (10). :>aid two sleeves are flushed
at the upstream end and the annular space (20) between the
two sleeves is sealed at both ends by transverse ring-
shaped walls (19a, 19b), providing a slight protrusion
(10a} of the outer sleeve (10) at the downstream end. Said
protrusion (l0a) may be placed in abutment with the
mainstream smoke outlet (7I) of a smoking article (7) and
the joint portion wrapped with wrapping paper (not shown).
The downstream end of the sles:ve (10) forms an inlet (17)
for receiving inhale smoke from the smoking article (7),
said inhale smoke may be drawn through an inhalation flow
path (13) defined by the elongate hollow of the inner
sleeve (10b) and inhaled through an upstream outlet-cum-
inlet ( 18 ) def fined by the upsi~ream open end of said inner
sleeve (10b). Said outlet-cum-inlet (18) is also provided
for receiving exhale smoke wherein an exhalation flow path
extending downstream from ;said ,outlet-cum-inlet (18)
channels said exhale smoke into openings (21) in a first
upstream section of the inner sleeve wall (10b) and through
a one-way valve system (16) provided in a first upstream
section of the annular space (20). Said exhale smoke is
filtered through filter means. (15) provided in a second
middle section of said annular space (20). Filtered air
from the filter means (15) ma.y be discharged via a third
upstream section of the annular space (20) and out into the
ambient environment through openings (22) in the outer
sleeve wall.
Figure 3 is an elongated sectional view of a third
CA 02273323 1999-OS-28
39
embodiment of a filter sleeve according to this invention.
Figure 3A is a three dimensional outline view of said
filter sleeve. The filter sleeve (1) comprises of an outer
sleeve (10) having a downstream end inlet (17) adapted for
receiving inhale smoke from 'the mainstream smoke outlet
(71) of a smoking article (7). An upstream end outlet-cum-
inlet ( 18 ) is provided for the inhalation of said inhale
smoke channelled through an inhalation flow path (13)
defined substantially by the elongate hollow of the sleeve
(10). Said upstream outlet-cum-inlet (18) is also provided
for receiving exhale smoke. An inner sleeve (10b) is
fitted coaxially into said outer sleeve (10) so that an
annular space (20) is provided between the outside wall of
the inner sleeve (lOb) and t:he inside wall of the outer
sleeve (10). Said inner leeve (lOb) has a closed
downstream end and is held in place by radially extending
tubes (14a) connecting the downstream section of the inner
sleeve (10b) to openings (22) in the wall of the outer
sleeve (10). The elongate hollow of the inner sleeve (lOb)
and tubes (14a) form the exhalation flow path of the sleeve
(10). Filter means (15) is provided in a middle section of
the inner sleeve ( lOb) . A one-way valve system ( 16 ) fitted
into the upstream opening of ithe inner sleeve (10b) allows
exhale smoke to reach the filter means (15), but
substantially prevents ambient air from being drawn into
the exhalation flow path in a reverse flow when the outlet-
cum-inlet (18) is inhaled. 'rhe filter sleeve (1) may be
attached to a smoking article (7) by placing the downstream
CA 02273323 1999-OS-28
portion (11) in end to end abutment with the mainstream
smoke outlet (71) of said smoking article (7) and
circumscribing the joint portion with wrapping paper (not
shown).
Figure 4 is an elongated sectional view of one
embodiment of a filter sleeve in communication with a
smoking article according to this invention. The filter
sleeve (1) comprises of an pouter sleeve (10) made of
activated carbon porous paper. A shorter inner sleeve
(lOb) is fitted coaxially into the elongate hollow of said
outer sleeve (10). The upstream ends of both sleeves are -
flushed and the annular space between the outside wall of
the inner sleeve (lOb) and the inside wall of the outer
sleeve (10) is sealed at botlh ends by transverse ring-
shaped walls (19a, 19b), providing a slight protrusion
(l0a) of the outer sleeve (10) at the downstream end. An
inlet ( 17 ) is def fined in the downstream end of the inner
sleeve (lOb) for receiving inh<~Ie smoke and an outlet-cum-
inlet (i8) is defined in the upstream end of said inner
sleeve (lOb) for the drawing of said inhale smoke and
receiving of exhale smoke. The inner sleeve (lOb) is
provided with a plurality of .apertures (23) in its wall.
The outer surface of said inn~sr sleeve ( 10b) is overlaid
with a thin film (24), said film (24) is punched to achieve
f laps ( 16 ) corresponding to they apertures ( 23 ) . Said f laps
(16) are resiliently biased to close said apertures (23) so
that when smoke is exhaled into the outlet-cum-inlet (18),
said smoke may move along the elongate hollow of said inner
CA 02273323 1999-OS-28
41
sleeve ( lOb) , whereby said f laps ( 16 ) move outwardly toward
the outer sleeve (10) to open said apertures (23), thereby
allowing exhale smoke to access the filter materials (15)
embodied in the wall of the outer sleeve (10) through said
apertures (23). The downstream protrusion (l0a) of the
outer sleeve (10) abuts the mainstream smoke outlet of a
smoking article (7), and the joint portion is circumscribed
with a wrapper (25). The upstream portion (12) of said
outer sleeve (10) is circumscribed with tipping paper (26).
The inner sleeve may suitably be made with metallic,
ceramic, polymeric or composite materials. Low porosity or
air impermeable paper or plastic may be particularly
suitable. Suitable materials for making the film and flaps
include paper, plastic, rubber or the like.
The following are some modifications which may be made
to this embodiment:
(a) the adaptation of diaphragms as valve members instead
of f laps .
(b) the location of apertures. only toward the upstream end
of the inner sleeve wherein the valve member may
comprise of a single cylindrical coaxial flap having
its upstream end portion sealed to the outside wall of
the inner sleeve at a point upstream of the apertures.
A filter plug may be provided in the downstream
section of the elongate hollow of the inner sleeve for
filtering inhale smoke.
( c ) the location of aperture:> only toward the upstream end
of the inner sleeve wherein a movable reed or ball
CA 02273323 1999-OS-28
42
valve member may be provided inside the hollow of the
inner sleeve so that it may be drawn to close the
apertures when the article is inhaled. Inhale smoke
may be drawn through pores in the valve member wherein
said valve member may also be adapted as a filter plug
for filtering said inhale smoke. In a further
variation, inhale smoke may be drawn through detour
flues linking a downstream section of the inner sleeve
to an upstream section oi° said inner sleeve.
(d) the location of apertures only toward the downstream
end of the inner sleeve wherein the valve member may
comprise of a cylindrical coaxial flap having its
downstream end portion ~;ealed to the inside wall of
the outer sleeve.
(e) the use of an inner sleeve having a smaller external
diameter toward the downstream end wherein clearance
space for valve movement and exhale smoke may be
improved toward said downstream end.
(f) the variation of aperture sizes, for example, the
larger apertures may be provided toward the downstream
end of the inner sleeve or vice versa. The film may
attach to any side of the flaps.
(g) the use of an inner sleeve having some flat outer
surfaces for easier opening and closing of valve
f laps .
(h) the siting of valve flaps inside craters, grooves or
recesses in the outside wall of the inner sleeve to
provide more height clearance for said valve flaps to
CA 02273323 1999-OS-28
43
open and close freely.
Figure 5 is an elongai;ed sectional view of one
embodiment of a filter sheath according to this invention.
The f filter sheath ( 3 ) comprises of a sheath ( 30 ) made of
non-combustible activated carbon porous paper that is of
sufficient porosity to air but is significantly impermeable
to sidestream smoke, said sheath (30) is adapted for
overlaying the sidestream smoke emission surfaces of a rod
of smokable material (7).
Figure 6 is an elongated sectional view of one
embodiment of a filter sheath laid over a rod of smokable
material in pre-packed form according to this invention.
Figure 6A is a three dimensional outline view of the
orifice and sliding door of said filter sheath. The filter
sheath (3) comprises of a sheath (30) made of non-
combustible activated carbon porous paper that is of
sufficient porosity to air but is significantly impermeable
to sidestream smoke. Said sheath (30) is laid over the
sidestream smoke emission suo:faces of a rod of smokable
material (7) so that the mainstream smoke outlet (71) of
said rod of smokable material (7) corresponds with the
downstream open end of the sheath (30). Said sheath (30)
has an orifice (31) with a sliding door (33) toward the
upstream end for allowing tlhe ignition of said rod of
smokable material (7). The portion about the joint of the
sheath (30) with the filter-tip (72) of said rod of
smokable material (7) is circumscribed with tipping paper
CA 02273323 1999-OS-28
44
(26).
Figure 7 is an elongated sectional view of one
embodiment of a comprehensive filter smoking article
according to this invention. The comprehensive filter
smoking article (5) comprises of a non-combustible,
sufficiently porous activated carbon sheath (30), said
sheath (30) overlays a rod of ;smokable material (7) so that
the mainstream smoke outlet (71) of said rod of smokable
material (7) protrudes out of the mouth-side downstream
open end of the sheath (30). Said downstream open end of
the sheath (30) abuts the downstream protrusion (l0a). of
the filter sleeve (1) described in Figure 4 so that the
mainstream smoke outlet (71) of the rod of smokable
material (7) mates into the downstream inlet of the sleeve
(10). The joint portion of: the sheath (30) with the
downstream protrusion (l0a) is circumscribed with a wrapper -
(25). The upstream portion (12) of said sleeve (10) is
circumscribed with tipping paper (26). Further, the sheath
( 30 ) is provided with a lighi=ing surface ( 32 ) wherein an
upstream open end of the sheath (30) is covered with a mesh
made of a non-combustible filter material, said mesh is
adapted for allowing a flame or heat source placed near or
on said lighting surface (:32) to ignite said rod of
smokable material (7).
The following tests were conducted to investigate
various aspects of this invewtion:
a) To estimate the feasibility of a probable type of
CA 02273323 1999-OS-28
45
valve system, a 42 mm inner sleeve was cut from a
drinking straw having an internal diameter of 5 mm.
A plurality of apertures were made in the wall of said
inner sleeve. Flaps made' from thin plastic cuttings
were glued to the side of each aperture. The inner
sleeve was then fitted coaxially into the elongate
hollow of an outer sleeve cut from a drinking straw
having an internal diameter 8 mm. Closing one end of
the inner sleeve with a finger, exhalation was
executed into the opposite open end of said inner
sleeve. No perceptible :resistance to exhalation was
felt. During inhalation however, a clear resistance
was felt as the flaps closed over the apertures.
b) To estimate the resistance to exhalation of a probable
type of filter material, a sleeve of 42 mm length was
cut from a drinking straw of 22 mm external
circumference. The downstream end of said sleeve was
closed. Four strips of 27 mm length each were cut
from the sleeve wall immediately adjacent the
downstream closed end to create outlets. A double
layer of cotton fabric was wound around said outlets.
The remaining 15 mm opposite end of the sleeve was
retained for insertion into the mouth. Said fabric
material showed no pEarceptible resistance when
exhalation was executed into the upstream open end of
the sleeve.
In use, a sleeve of 42 mm length, when added to
a rod of smokable material, is likely to be acceptable
CA 02273323 1999-OS-28
46
to smokers as the article or a pack of it can still be
put neatly into a shirt pocket. If a sleeve of about
42 mm length, for example, is added to a cigarette of
about 22 mm external diameter, the shape, thickness
and length of said cigarette may somewhat resemble a
conventional ball-point pen without its cover and cone
tip.
c) In another test of resistance to exhalation, two short
pieces of drinking straw of 22 mm circumference each
were placed coaxially 20 mm apart to form a straight
but broken line. Two layers of cotton fabric were
used to circumscribe the ends of the two straws facing
each other so that the cotton fabric formed a
cylindrical hollow joining the elongate hollows of the
two straws. The downstream open end of one straw was
closed with a finger and exhalation was executed into
the opposite upstream open end of the other straw. No
..
perceptible resistance to exhalatior. was felt.
d) In a test of porosity to .air and combustion sustenance
of a probable type of sheath material, a lit cigarette
was circumscribed with three layers of cotton fabric
so that the cotton fabric: protruded beyond the lit end
of the cigarette. The protruding portion of the
cotton fabric was held closed. The cigarette
continued burning and eventually burned through the
cotton fabric, demonstrating that porosity necessary
for the sustenance of tobacco combustion is relatively
easy to achieve. This observation is applied directly
CA 02273323 1999-OS-28
47
in this invention by overlaying at least a significant
portion of the sidestream releasing surfaces of a rod
of smokable material with a sheath that is
sufficiently porous to a:ir. This application makes
possible the elimination ~of the cylindrical air space
between a rod of smoka:ble material and a filter
sheath, thus considerably reducing the thickness
associated with sidestream filtration. Combustion
products may be confined. The use of a porous sheath
capable of sustaining combustion also makes redundant
the use of a motorized impeller or fan. By adjusting
the degree of air permeability or porosity of the
sheath, said sheath may be adapted to enable minimal
sustenance of combustion of smokable material at a
reduced rate of sidestream smoke production.
There are many existing filter materials that may be
adapted for use in the present: invention. Also known are
methods for making flame resistant fibers, yarn and sheets
which may be adapted as a flame resistant support of the
present invention. Further, there are various methods for
imparting flame resistance to sheet materials. Variations
in colour, texture or porosity of filter materials may be
achieved using methods well known in paper or fabric
making.
The following materials may possibly be adapted for
use as the filter material o~f the filter sleeve and/or
filter sheath of the present invention:
CA 02273323 1999-OS-28
48
a) US Pat. 5,482,906 disclosed an adsorption material
comprising milled activated carbon fiber together with
fibrils of a polytetrafluoroethylene resin. The
adsorption material ha:~ high bulk density and
mechanical strength, forms less black dust, retains
activity essential to activated carbon fibers,
provides less pressure drop, good permeability to
liquid or gas, and is easily formed into various
shapes. The material c.an be formed into a sheet
preferably from 1 to 0.1 mm thick, but it may be
reduced to as little as 0.02 mm.
b) US Pat. 5,482,773 disclosed activated carbon-loaded
polymeric fibrids having high surface area and
adsorption activity. lwen though the carbon is
completely encapsulatedi by the polymer, the
microporous surface area of the fibrids- is
substantially greater than that of non-loaded fibrids.
Also encompassed are wet-laid composite sheet
structures comprising papers of such fibrids with or
without short staple fibers, or mats of such fibrids
and fiber fluff and composite sheet structures formed
by hydrolacing such fib:rids with synthetic fibers.
This invention also provides non-shedding, fibrous
sheet structures containing carbon-loaded fibrids
which are suitable for separating gaseous impurities
from air and dissolved impurities from water and other
liquids. High levels of: carbon can be incorporated
into the structures with a wide range of densities and
CA 02273323 1999-OS-28
49
air permeability without the need for adhesives. One
can prepare papers with air permeabilities ranging
from 0.3 to 30 mm3/min/m2.
c) US Pat. 4,904,343 disclosed a toxic vapour adsorptive
non-woven activated carbon fabric.
d) US Pat. 4,565,727 disclosed a non-woven activated
carbon fabric of high sorptive capacity and high
porosity to fluid flow, ~>rodu~ed via the wet-laying
a
process and having a thickness of at least 0.005
preferably at least 0.01 inch.
e) US Pat. 4,520,623 disclosed an activated carbon fiber
spun yarn which may subsequently be woven into a
fabric.
f ) US Pat. 4, 495, 030 disclo:~ed an active carbon ffilter
paper excellent for removal of aerosols, particulates
and toxic vapors, having high porosity to fluid flow
at very low pressure drops, having thickness of at
least 0.005 preferably at least 0.01 inch.
g) US Pat. 4,401,588 disclosed an activated carbon fabric
made directly from aramid fabric in a single
activation step.
h) US Pat. 4,358,504 disclosed a flame retardant
activated carbon web. Treating an activated carbon
sheet with a selected flame retardant composition
consisting essentially of a basic ammonium phosphate,
preferably diammonium phosphate provides the
beneficial flame retardant character so that no after-
glow is exhibited and the adsorption characteristics
CA 02273323 1999-OS-28
of the sheet is not substantially reduced. The flame
retardant can be applied over a wide weight and
porosity range and can be used with a large number of
different types of activated carbon materials. Due to
its flame retardant properties, such a web may be
particularly suitable l:or use as the filtering
material of the filter sheath of the present
invention.
i) US Pat. 4,067,210 disclosed a warp knit fabric
containing highly activated carbon yarn produced on
commercially available fabric forming machines.
j) US Pat. 3,769,144 di:~closed a quilted fabric
containing high surface area carbon fibers.
k) US Pat. 3,149,023 disclosed a carbon filled sheet
having high strength, high absorptive and/or
adsorptive properties and being free from rub-off,
flaking and smudging.
The following patents disclosed materials that may be
adapted as a non-combustible or flame resistant support for
the filter sheath. Said materials may also be adapted for
use as a non-combustible or flame resistant lighting
surf ace
a) US Pat. 3,744,534 disclosed a flame resistant woven
fabric of activated carbon yarns in combination with
aromatic polymide yarns.
b) US Pat. 3,639,140 disclo:~ed a~ process for carbonized
cellulose fiber by treating with a specific strength
CA 02273323 1999-OS-28
51
increasing agent or a flame resistance improving
agent.
c) US Pat. 3,576,769 disclosed a semicarbonization of
thermally stable aromatic polymers resulting in fibers
or fabric that are es:aentially non-flammable and
thermally stable.
d) US Pat. 3,556,712 disclo::ed a method of making a high
tenacity and high flame-proof carbon fiber from a
cellulosic viscose rayon wherein a modified viscose
rayon fiber having a high degree of polymerization is
used as a starting cellu:Losic material.
e) US Pat. 3,235,323 disclosed a heat-resistant black
fibers and fabrics derived from rayon; a woven sheet
of this material can hold a half-pound of molten steel
(temperature of about 2700 F) without burning or
disintegrating. -
The present invention may make possible the following
advantages:-
The filter sleeve:
a) The filter sleeve may be slim and lightweight and
offer great convenience :in use.
b) A large exhale smoke receiving inlet and exhalation
flow path may provide fo:r effortless exhalation.
c) The wall of the sleeve may provide a huge surface for
receiving and filtering exhale smoke, thereby further
minimizing the resistance to exhalation.
d) The mouth-end of the filter sleeve may provide for
CA 02273323 1999-OS-28
52
hassle-free inhalation and exhalation.
e) The mouth-to-filter-to-environment distance nay be
reduced, thereby saving space and further reducing
resistance to exhalation.
f) The filter sleeve may be easily and inexpensively
manufactured.
g) A disposable pre-packed form of the filter sleeve
integrally in communication with a smoking article may
easily be produced in large quantities in a mass
production facility.
h) A filter sleeve of similar circumferential dimensions
as a cigarette or cigar, and provided in substantial
coaxial alignment in communication with said cigarette
or cigar, may be packed elegantly and economically
into a minimally altered cigarette or cigar box.
The filter sheath:
a) The filter sheath is slim; and lightweight.
b) It is easy and inexpensive to manufacture.
c) It may reduce sidestream pollution more effectively
than wrapping papers and less smoke cigarettes of the
prior art.
d) A sheath substantially unimpaired by combustion is
psychologically reassuring.
e} The sheath may remain pleasant to both sight and smell
during and after use.
f) Confinement of combustion may further reduce the risk
of accidental fires and bodily hurt.
CA 02273323 1999-OS-28 '
53
g) It is easier and more convenient to use than existing
accessory cigarette smok~a filtration devices.
The filter sleeve and/or filter sheath with a rod of
smokable material in a pre-packed form:
a) The article may be less polluting than conventional
smoking articles such as cigarettes, cigars or the
like.
b) It may provide for effortless exhalation.
c) It may be slim and lightweight and offer great
convenience in use.
d) It is easy and inexpensive to manufacture.
e) It is advantageously visible in use and may be
comforting and psychologically reassuring to both
smokers and non-smokers.
f) It is suitable for use in numerous social situations,
yet allows smokers to exhale in the conventional
manner when there are no nearby persons.
g) It is suitable for mass production.
h) It may filter smoke without substantially changing the
taste and other characteristics of the inhale smoke.
i) It may eliminate the need for loading and unloading of
tobacco, filter material:, monitoring and maintenance.
j) A disposable form of the: article may be appealing to
users.
k) It may provide a large external surface which may
carry health warnings, captions and the like, and be
safely held throughout the smoking process.
CA 02273323 1999-OS-28
54
1) The article's rigidity many reduce crumpling and allow
for more robust handling.
m) After use, the exhausted article may remain pleasant
to the sight and be dropped into a shirt pocket for
temporary storage if there is no nearby disposal bin.
