EP0461162B1 - Filtre a courbe de liberation du goudron uniforme - Google Patents

Filtre a courbe de liberation du goudron uniforme Download PDF

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Publication number
EP0461162B1
EP0461162B1 EP90904210A EP90904210A EP0461162B1 EP 0461162 B1 EP0461162 B1 EP 0461162B1 EP 90904210 A EP90904210 A EP 90904210A EP 90904210 A EP90904210 A EP 90904210A EP 0461162 B1 EP0461162 B1 EP 0461162B1
Authority
EP
European Patent Office
Prior art keywords
cigarette
smoke
cigarette smoke
filter element
filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP90904210A
Other languages
German (de)
English (en)
Other versions
EP0461162A1 (fr
Inventor
Warren Arthur Brackmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rothmans Benson and Hedges Inc
Original Assignee
Rothmans Benson and Hedges Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB898904752A external-priority patent/GB8904752D0/en
Priority claimed from GB898909660A external-priority patent/GB8909660D0/en
Application filed by Rothmans Benson and Hedges Inc filed Critical Rothmans Benson and Hedges Inc
Publication of EP0461162A1 publication Critical patent/EP0461162A1/fr
Application granted granted Critical
Publication of EP0461162B1 publication Critical patent/EP0461162B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
    • A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
    • A24D3/04—Tobacco smoke filters characterised by their shape or structure

Definitions

  • the present invention relates to a novel cigarette smoke filter element which is able to provide a more uniform tar delivery profile to the smoker than has heretofore been possible, and to cigarettes incorporating such filter elements.
  • Patent no. 1,339,238 proposed placing a disc of a blocking plug between a tobacco rod and an ordinary cellulose acetate filter rod. This disc has an orifice for smoke to flow through.
  • the disadvantage of this design is that the pressure drop of the cigarette increases to an unacceptable level as the orifice of the plug becomes clogged up at the later puffs.
  • U.S. Patent no. 3,882,877 proposed placing a disc of microfine fibres in between two filter rod segments. This filter is designed to increase filtration efficiency. However, it could not cause the "tar" delivery to be more even, furthermore the pressure drop may increase to an unacceptable level at the later puffs.
  • U.S. Patent no. 4,747,418 uses a filter element in the form of a membrane having a large number of tiny openings in combination with openings downstream of the membrane through which air may be drawn or conventional filter substance in an attempt to produce a more uniform tar delivery. Again a complicated and expensive structure is required.
  • EP-A-364253 describes a cigarette filter element which includes an axially extending barrier tube of microfine fibers with a diameter of between 0.5 and 10 microns an located so that at least part of the gas flow passes through the wall of the barrier tube.
  • EP-A-364253 requires specific combinations of elements with this barrier tube.
  • US-A-3621852 describes a cigarette filter assembly in which cigarette smoke is directed to and through an outer annulus of cigarette smoke filter material to an inner core of the filter element and then to the smoker.
  • an improved filter structure wherein two different filter materials are combined to achieve a more uniform tar delivery.
  • a cigarette smoke filter element which comprises:
  • cigarette smoke directed from a cigarette into the outer cylinder passes first through the outer cylinder, and then through the inner cylinder into the axial low resistance flow path.
  • the tobacco smoke is forced to flow by a progressively-increasing length of flow path through the outer cylinder as the progressively greater proportion of the length of the inner cylinder becomes clogged with tar filtered from the tobacco smoke. As explained in more detail below, this effect leads to a more uniform delivery of tar in the cigarette smoke to the smoker's mouth.
  • the cylinder of microfine fibres may be provided between two outer porous support layers.
  • the microfine fibres may be formed as described in the aforementioned U.S. Patent no. 3,882,877, the disclosure of which is incorporated herein by reference.
  • the microfine fibres in the cylindrical layer thereof may have any convenient diameter to achieve the desired filtration as described herein, generally from about 0.5 to about 10 microns.
  • the cylindrical layer may have any convenient thickness to achieve the desired filtration as described herein, generally from about 0.05 to about 4 mm.
  • the microfine fibres may be packed to any desired degree to achieve the desired filtration, generally from about 0.05 to about 0.3 g/cc.
  • the outer annulus of filter material may comprise any of the well-known filtration materials commonly employed in cigarette filters, generally cellulose acetate tow with its fibres extending predominantly axially along its length, or a non-woven fibrous material, such as DANAKLON ES (polypropylene/polyethylene bicomponent fibres made by Danaklon, Denmark).
  • DANAKLON ES polypropylene/polyethylene bicomponent fibres made by Danaklon, Denmark.
  • microfine fibres are a highly efficient cigarette smoke filtration medium and function to remove liquid components from the smoke, as described more fully in U.S. Patent no. 3,882,877.
  • the filtration is so efficient that the filter can rapidly become blocked and permits no further smoke filtration to occur.
  • the result of this filtration operation is that the smoke entering the smoker's mouth has a substantially uniform tar content and the problem of increasing tar yield from the cigarette is compensated for by providing progressively increased filtration of the tobacco smoke before it reaches the smoker's mouth, without introducing an unacceptable level of pressure drop.
  • a method of achieving a more uniform delivery of tar in tobacco smoke entering a smoker's mouth from a cigarette characterized by causing the tobacco smoke to pass from a burning cigarette first into an outer cylinder of tobacco smoke filter material of higher resistance to smoke flow, and then through an inner cylinder of microfine fibres into an axial flow path to the smoker's mouth of lower resistance to smoke flow, filtering filterable materials, including tar, from the smoke both in the outer cylinder and the inner cylinder, and causing said smoke to pass through a progressively longer flow path through said outer cylinder as a progressively increased proportion of the inner cylinder becomes incapable of effecting filtration, thereby to remove progressively greater proportion of filterable materials, including tar, from the tobacco smoke.
  • Figure 1 is a schematic sectional view of a novel cigarette filter constructed in accordance with one embodiment of the invention.
  • a cylindrical cigarette 10 includes a cigarette rod 12 and a novel filter 14, having a construction which the applicants regard as the current best mode of carrying out the invention.
  • the cigarette rod 12 has a conventional paper wrapper 16 and is joined to the filter 14 by a conventional cork wrap 18.
  • the filter 14 comprises an outer annulus 20 of conventional cellulose acetate tow material having an outer wrap 22.
  • a cylinder of microfine fibres 24 abuts the inner radial extremity of the annulus 20 and typically is supported between outer layers of low flow resistance fabric.
  • the cylinder 24 is sandwiched between the annulus 20 and an inner plug 26 of low flow resistance material, such as low flow resistance acetate.
  • the inner plug 26 may be omitted entirely, if desired, but preferably is employed to provide mechanical strength and stability to the structure.
  • Alternative support structures may be employed, such as an extruded plastic core with a star-shaped cross-section or other convenient shape providing smoke flow channels radially inwardly of the cylinder 24.
  • the filter is sealed against the flow of cigarette smoke directly from the cigarette rod 16 to the acetate plug 26, such as by crimping 32 the acetate plug 26, and/or by providing a circular baffle 34 overlying the end of the acetate plug 26.
  • the smoke follows the path of least resistance so that, initially, the smoke flows only for a short distance through the annulus material 20 before flowing through the microfine fibres into the acetate plug 26.
  • the microfine fibres effect efficient filtration of the tobacco smoke to remove smoke-borne particulates including tar-containing droplets and the fibres eventually are unable to effect further filtration. Accordingly, the microfine fibres in the cylinder 24 become, in the direction towards the smoking end of the cigarette 10, progressively unable to effect filtration.
  • the cigarette smoke therefore, is required to transverse a progressively longer path through the annulus filtration material 20 before the smoke can travel radially inwardly into the acetate plug 26.
  • a progressively greater degree of filtration is effected by the annulus material 20 and, thereby, a progressively greater degree of overall filtration is effected as the cigarette 10 is smoked, thereby compensating for the progressively greater tar production by the cigarette rod 12.
  • smoke can pass from the annulus material 20 directly into the smoker's mouth.
  • the predominant smoke flow path is via the acetate plug 26 because of its lower resistance to smoke flow.
  • an annular barrier may be provided overlying the smoking end of the annulus material 20 to force all the smoke to flow to the smoker's mouth through the acetate plug 26.
  • the filter element 10 may be formed in any convenient manner.
  • the acetate plug 26 is replaced by an extruded plastic core having a star-shaped cross section so as to provide a plurality of channels through which the filtered smoke can pass to the smoker.
  • the plastic core then is reciprocated in front of a fine fibre extruder on a continuous basis.
  • the plastic core is rotated about its axis, so that the fibers are collected in an uniform layer 24 on the periphery of the core i.e., at the radial extremities of the points of the star.
  • the relatively few microfine fibers which may randomly extend into the air passages between the points of the star-shaped cross section are not sufficient to affect significantly the low pressure drop ducts between the legs of the star.
  • the continuous rod then is passed through a filter-making machine, wherein the core is periodically crimped and the normal high efficiency filter material 20 is placed on the outside of the layer 24 of microfine fibres.
  • the filter then is wrapped in conventional plug wrap 22 and cut at the crimped points to provide a plurality of filter elements 14.
  • the present invention provides a novel cigarette filter structure to provide a uniform delivery of tar to a smoker by providing for successively greater degrees of filtration as the cigarette is smoked, without producing unacceptable levels of pressure drop.
  • Cigarettes are a staple item of commerce.

Landscapes

  • Cigarettes, Filters, And Manufacturing Of Filters (AREA)
  • Fats And Perfumes (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)

Abstract

La présente invention se rapporte à un filtre (14) pour la fumée du tabac, qui produit une courbe de libération du goudron plus uniforme sans chute de pression inacceptable en amenant la fumée de la cigarette à suivre un trajet d'écoulement progressivement plus long à travers un cylindre externe (20) en matériau d'étoupe de filtre à résistance élevée à l'écoulement, avant de passer radialement vers intérieur à travers un cylindre (24) en fibres microfines en suivant un trajet d'écoulement à faible résistance (26) jusque dans la bouche du fumeur. L'augmentation progressive du trajet d'écoulement a pour résultat un engorgement progressif du cylindre en fibres microfines par le matériau filtré au fur à mesure que la cigarette est fumée.

Claims (5)

  1. Elément de filtre (10) pour fumée de cigarette qui comprend :
    un cylindre extérieur allongé (20) fait d'une matière de filtre pour fumée de cigarette,
    des moyens (26) définissant un chemin axial de fumée de cigarette situé radialement à l'intérieur dudit cylindre allongé extérieur (20),
    ledit cylindre allongé extérieur (20) de matière de filtre pour fumée de tabac ayant une plus grande résistance à l'écoulement de la fumée de cigarette à travers lui que ledit chemin d'écoulement axial, de sorte que la fumée de cigarette qui entre dans le cylindre allongé extérieur (20) cherche de préférence un chemin d'écoulement dirigé radialement vers l'intérieur, pour atteindre le chemin axial pour fumée de cigarette, et
    des moyens (34) de direction du chemin d'écoulement de la fumée de tabac, formés de moyens du type chicane placés exclusivement à une extrémité amont de l'élément de filtre, dans la direction de l'écoulement de la fumée de cigarette à travers l'élément de filtre (10), pour diriger la fumée de cigarette provenant d'une cigarette à laquelle l'élément de filtre est fixé, exclusivement vers ledit cylindre allongé extérieur (20) de matière de filtre pour la fumée de tabac, caractérisé :
    en ce que le cylindre allongé extérieur (20) de matière de filtre pour fumée de cigarette est une matière de filtre classique en mèche d'acétate de cellulose et est ouvert pour l'écoulement de la fumée de cigarette à ses deux extrémités,
    un cylindre allongé (24) composé de fibres microfines, dans lequel chaque fibre à un diamètre de 0,5 à 10 microns, ledit cylindre allongé intérieur ayant une épaisseur de 0,05 à 0,4 mm et une densité de 0,05 à 0,3 g/cm3, et
    lesdits moyens (26) qui définissent ledit chemin axial de la fumée de cigarette supportant le cylindre allongé intérieur (24) et définissant ledit chemin axial de la fumée de cigarette radialement à l'intérieur desdits cylindres allongés intérieurs (24) en fibres microfines.
  2. Elément de filtre (10) selon la revendication 1, caractérisé en ce que lesdits moyens de support (26) comprennent une tige de matière d'acétate à faible résistance à l'écoulement placée dans ledit chemin axial de la fumée de la cigarette.
  3. Elément de filtre (10) selon la revendication 2, caractérisé en ce que ladite matière d'acétate à faible résistance est resserrée pour empêcher la fumer de tabac de s'écouler à l'extrémité amont de l'élément de filtre (10).
  4. Elément de filtre (10) selon la revendication 1, caractérisé en ce que lesdits moyens de support (26) comprennent un tube en matière plastique allongé ayant une section en forme d'étoile, ledit cylindre allongé (24) de fibres microfines étant supporté au niveau des pointes de ce cylindre, de sorte qu'il se forme plusieurs chemins d'écoulement de la fumée de cigarette radialement à l'intérieur dudit cylindre (24) de fibres microfines.
  5. Elément de filtre (10) selon une quelconque des revendications 1 à 4, en combinaison avec une tige de cigarette dans une cigarette.
EP90904210A 1989-03-02 1990-03-01 Filtre a courbe de liberation du goudron uniforme Expired - Lifetime EP0461162B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB8904752 1989-03-02
GB898904752A GB8904752D0 (en) 1989-03-02 1989-03-02 Uniform tar delivery profile filter
GB8909660 1989-04-27
GB898909660A GB8909660D0 (en) 1989-04-27 1989-04-27 Uniform tar delivery profile filter-11
PCT/CA1990/000070 WO1990009741A1 (fr) 1989-03-02 1990-03-01 Filtre a courbe de liberation du goudron uniforme

Publications (2)

Publication Number Publication Date
EP0461162A1 EP0461162A1 (fr) 1991-12-18
EP0461162B1 true EP0461162B1 (fr) 1997-07-09

Family

ID=26295035

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90904210A Expired - Lifetime EP0461162B1 (fr) 1989-03-02 1990-03-01 Filtre a courbe de liberation du goudron uniforme

Country Status (6)

Country Link
EP (1) EP0461162B1 (fr)
JP (1) JP2701974B2 (fr)
AU (1) AU629320B2 (fr)
CA (1) CA2049573C (fr)
DE (1) DE69031032T2 (fr)
WO (1) WO1990009741A1 (fr)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8823902D0 (en) * 1988-10-12 1988-11-16 Rothmans Int Tobacco Cigarette filter rod elements & cigarettes incorporating such filter rod elements
US5746230A (en) * 1990-08-24 1998-05-05 Philip Morris Incorporated Concentric smoking filter having discrete tow and web filter media
US5365951A (en) * 1990-08-24 1994-11-22 Philip Morris Incorporated Concentric smoking filter having cellulose acetate tow periphery and carbon-particle-loaded web filter core
GB9117118D0 (en) * 1991-08-08 1991-09-25 Rothmans Benson & Hedges Control of cigarette smoke chemistry
AU699329B2 (en) * 1991-08-08 1998-12-03 Rothmans International Services Limited Control of cigarette smoke chemistry
GB9122935D0 (en) * 1991-10-30 1991-12-18 Rothmans Benson & Hedges Novel cigarette system
TR26626A (tr) * 1992-12-18 1995-03-15 Rothmans Benson And Hedges Inc Yeni cok icimli sigara sistemi.
TR28750A (tr) * 1992-12-18 1997-02-28 Rothmans Benson & Hedges Münferit sigaralarin, kismen icilmesi, söndürülmesi ve ondan sonra tekrar icilmesine, müsaade eden yeni bir sigara strüktürü.
GB9307710D0 (en) * 1993-04-14 1993-06-02 Rothmans Benson & Hedges Smoking apparatus-l
DE4322967C1 (de) * 1993-07-09 1994-10-13 Rhodia Ag Rhone Poulenc Filtertow aus Celluloseacetat, dessen Herstellung und Verwendung als Tabakrauchfilterelement
US7987856B2 (en) * 2005-12-29 2011-08-02 Philip Morris Usa Inc. Smoking article with bypass channel
GB0713905D0 (en) * 2007-07-17 2007-08-29 British American Tobacco Co Cellulose acetate thread in filter

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1097748A (en) * 1965-05-27 1968-01-03 Monsanto Co Cigarette filter
US3502087A (en) * 1968-07-05 1970-03-24 Ernest J Romano Cigarette filter
US3621851A (en) * 1969-11-26 1971-11-23 Kata Mfg & Filtering Co Filter for smoker's article
US3854384A (en) * 1971-05-24 1974-12-17 Brown & Williamson Tobacco Method of making tobacco smoke filters
GB1360611A (en) * 1971-06-30 1974-07-17 Molins Ltd Cigarette filters
DE3624661A1 (de) * 1986-07-22 1988-02-04 Rhodia Ag Ventilierte zigarette
GB8823902D0 (en) * 1988-10-12 1988-11-16 Rothmans Int Tobacco Cigarette filter rod elements & cigarettes incorporating such filter rod elements
DK499289A (da) * 1988-10-12 1990-04-13 Rothmans Int Tobacco Stangelementer til cigaretfiltre og cigaretter udstyret med saadanne stangelementer

Also Published As

Publication number Publication date
DE69031032T2 (de) 1998-01-29
AU629320B2 (en) 1992-10-01
DE69031032D1 (de) 1997-08-14
CA2049573A1 (fr) 1991-09-02
AU5268990A (en) 1990-09-26
CA2049573C (fr) 1997-01-14
JP2701974B2 (ja) 1998-01-21
WO1990009741A1 (fr) 1990-09-07
JPH04503753A (ja) 1992-07-09
EP0461162A1 (fr) 1991-12-18

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