IE44778B1 - Cigarette filter - Google Patents

Abstract

In order to improve the pleasure of smoking, a tube which is shorter than the filter is arranged in the filter, with substantially equal axis, and does not extend to the end of the filter at the end facing the smoker. There thus arises a distribution zone for the smoke flowing through the tube in order to disperse the unfiltered fraction of the smoke before its entry into the mouth. The length of the tube is 1/2 to 4/5, preferably about 2/3, of the length of the filter. The apparatus possesses a charging device (14) for continuously feeding a length of tubing (15), a cutting device (16) for the latter, a mandrel plug (19) for passing on the pieces of tubing, a charging device (12) for continuously feeding the filter material (13), a nozzle (17) arranged around the mandrel plug (19) for the filter material (13), a second charging device (43) for continuously feeding the wrapping paper (42), a device (36, 37) for the cylindrical compression and wrapping of the filter material (13) with the wrapping paper (42), and a device (49) for dividing the filter rod (11) into sections (50) of predetermined length.

Description

This invention relates to a cigarette filter, a cigarette incorporating such a filter and to a method and apparatus for making the filter, Heretofore, various types of filters have been devised for use 5 in cigarettes in order to screen out certain filterable materials which comprise the tobacco smoke screen. For example, filters made up of fibrous materials, such as a cellulose acetate, have been known for filtering out particulate matter from the smoke generated during smoking. However, such a filtering medium between a smoker's mouth and the tobacco column of the cigarette generally require an additional drawing or inhaling force on the part of the smoker in order to draw the smoke through _the filtering material. As a result, a practical limit has be^n imposed on the amount of particulate matter that can be filtered out by a particular filtering material due to the need . to have a pressure drop across a filter that can be tolerated by a smoker without discomfort.

In more recent times, attempts have been made to dilute the smoke stream from a cigarette with ventilating air to reduce the quantity of particulate matter drawn into a smoker's mouth for each puff while allowing the taste to pass through. Some of these attempts have used bypass arrangements by which a greater or lesser proportion of the 4477s cigarette smoke can be bypassed around a filter medium and drawn into a smoker's mouth. In some cases, the filters have been provided with passageways through which a portion of unfiltered smoke can be passed directly to the smoker's mouth, for example, as in U.S. Patent No. 860 Oil. Such passageways have usually been provided directly in the filter material and the filter material has been constructed so as to be collapsed manually about the passageway to constrict the size of the passageway and, thus, reduce the proportion of unfiltered smoke passing through a'smoker, for example, as described in U.S. Patents Nos. 242 925 and 3 270 750.

One of the reasons for utilizing filters with bypass passages is that the flow of unfiltered smoke can be drawn through the filter at a greater speed than the filtered flow which passes through the filtered material so that the faster flow can impinge upon the tongue and taste buds of the smoker at a greater impact speed than the normal. This is believed to impart a greater taste to the smoke. However, such direct impingement upon the tongue, can be irritating especially during the next-to-last and last puff when the burning tobacco is proximate the filter tip and the smoke is hot.

According to the invention there is provided a cigarette filter comprising an open tube defining a passageway extending from one end of the filter which is (in use) placed adjacent the cigarette tobacco for receiving a first portion of smoke, a layer of compacted filter material positioned circumferentially about said tube and extending from adjacent the said one end of the filter beyond the opposite end of the tube to the other (mouth) end of the filter for receiving (in use) a second portion of smoke, and a cylinder of plugwrap about said layer of filter material. '3 Preferably said plugwrap is porous paper.

Preferably the filter material is less compacted adjacent the mouth end of the filter than about the tube so for dispersing smoke emanating from the tube without significantly filtering it.

The invention includes a filter tipped cigarette comprising a tobacco section joined to a filter as described above.

Preferably the filter is joined to the tobacco section by tipping material having a plurality of air-conveying perforations.

The perforations are preferably dimensioned and positioned so 10 that for a given draw a desired amount of diluted and filtered smoke and substantially unfiltered and dispersed smoke enter the smoker's mouth.

The invention also includes a method of making a cigarette filter as described above, comprising the steps of: a) providing a first continuous stream of hollow tubing from a source; b) prbvidihg a second continuous stream Of fibrous filter material from a source; c) severing said first continuous stream of hollow tubing into predetermined lengths-while maintaining said lengths in axial alignment; d) placing said streams in juxtaposition during travel while simultaneously enveloping said second stream of fibrous material circumferentially about said first stream of tubing, e) feeding said lengths of hollow tubing into said second stream 25 of fibroils material in axial alignment therewith at spaced apart -intervals; f) generating a third stream of paper; g) constricting said second stream about said lengths of hollow tubing to frictionally engage said lengths of hollow tubing for continued travel therewith; h) circumferentially enveloping said third stream about said juxtaposed and constricted first and second streams during continued travel of said first, second and third streams to form a filter rod; and i) severing the filter rod.

The inyenti'pn also includes apparatus for making cigarette filter as described above comprising: a) means for supplying a stream of tubing; b) a cutter for receiving and severing said tubing into predetermined lengths; c) a mandrel defining a passageway connecting with said cutter and providing passage for said lengths of tubing therethrough; d) means for supplying a stream of fibrous material; e) means circumferentially enveloping said mandrel for directing said supplied stream of fibrous material circumferentially about said mandrel; f) means extending downstream of said mandrel and being integral therewith for feeding said lengths of tubing into said circumferentially positioned fibrous material in axial alignment therewith and at spaced apart intervals; g) means for supplying a stream of paper; h) forming means for receiving said filter material containing said spaced apart lengths of tubing and paper to circumferentially envelop the paper stream about said juxtaposed streams of filter and material and tubing to form a filter rod; i) means for eutting said filter rod into predetermined sections.

A filtered tipped cigarette according to the invention allows a portion of substantially unfiltered but dispsersed smoke to enter a smoker's mouth at high velocity while diluting the smoke with drawn-in air in the mouth.

The preferred form of filter is constructed of a preferably rigid tube, a layer of compacted filter material and a cylinder of perforated or inherently porous plugwrap paper. The tube defines a smoke passage of constant cross-sectional area throughout having a draw resistance for controlling the amount of unfiltered smoke delivered to a diffuser prior to entry into a smoker's mouth._ The portion of filter material adjacent the mouth end of the filter is less compacted and acts as a diffuser. The diffuser does little to filter the smoke and acts to disperse the smoke. The layer of filter material surrounding the tube and forming the diffuser preferably is continuous filament cellulose acetate. The plugwrap paper is porous like tea bag paper, The tipping paper which connects the filter to the tobacco column is provided with a plurality of perforations, the number and size of which define the quantity of air to be mixed with the filtered smoke and the substantially unfiltered smoke and draw resistance. The draw resistance through the perforations and filter complement the draw resistance of the smoke through the tube and diffuser whereby for a given draw a flesired amount of substantially unfiltered smoke and ventilation air are drawn into the smoker's mouth. - 6 ? The means for enveloping the fibrous material about the tube feeding mandrel and the forming means can be of known construction, as is conventionally used in forming filter rods of fibrous filter material of solid construction. For example, this means can be in the form of a nozzle having a Venturi-opening and an air supply as described in British Patent Specification No. 933,827.

The tube is continuously drawn from a supply and is cut into predetermined lengths prior to being advanced to the mandrel. The mandrel is provided with an internal feed for selectively delivering the cut lengths of rods to the fibrous material.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended diaims taken in conjunction with the accompanying drawings in which: Figure 1 illustrates a schematic view of an apparatus for making the hollow filter rod with diffuser according to the invention; Figure 2 illustrates an enlarged partly cross-sectional view of the apparatus of Figure 1; Figure 3 illustrates a perspective view of the portion of the mandrel showing the drag working against a length of rod; Figure 4 is an elevation view of the rod cutting mechanism; Figure 5 illustrates a cross-sectional view of a cigarette having a filter made in accordance with the invention; Figure 6 is a cross-section of a cut length of filter showing the hollow tube sections axially aligned and sequentially spaced along the length of the filter rod; and Figure 7 is a cross-section taken along lines 7-7 of Figure 1 and showing an anvil heat sealing the plugwrap paper.

Referring to Figure 1, the apparatus 10 for making a hollow cigarette filter with filter rod ll includes a means 12 for supplying a stream of fibrous filter material 13 such as a cellulose acetate tow and a means such as a supply reel 14 for supplying a stream 5 of tubing 15, for example,-of hollow plastic material. The apparatus 10 includes a tube cutting means 16 receiving tubing 15 and severing same into predetermined lengths, a means 17 for shaping the stream of fibrous filter material 13 about the tubing 15 and a rod former 18 of conventional construction for wrapping the streams 10 of filter material and tubing into the filter rod 11.

Referring to Figures 1 and 4, tube cutter 16 is positioned downstream Of the supply reel 14 and includes opposed draw rollers 20 and 20', cutting roller 21 having cutting blades 22 and opposed feed rollers 23 and 23', these rollers being supported by housing 15 24. Tubing 15 is drawn along passageway 25 by draw rollers 20 and ' by the frictional engagement of peripheries of the rollers against the tubing. Cutting roller which rotates in timed sequence with draw rollers 20 and 20' then severe tubing 15 into short Cutting roller 21 acts against free Tubing sections 26 are then forwarded along passageway 25 and into nozzle 32 through connecting rod 19.

Connecting rod 19 includes a leaf spring 29 which acts as a drag against short tube sections 26.

Referring to Figure 2, the means 17 for shaping the stream 25 of filter material 13 about the tubing 15 includes a nozzle 32 which is similar to that described in British Patent Specification 933,827. predetermined sections 26. wheeling anvil roller 27.

That is, the nozzle 32 includes an internal bore 33 of Venturi-shaped configuration, an annular air chamber 34 which receives air from a suitable air supply source (Figure 1) and surrounds the Venturi-shaped bore 33, and a Venturi-opening 35 communicating the chamber 34. The entrance end of the nozzle bore 33 is sized to receive the stream of filter material 13 with the material in a spread and decrimped manner from the filter material supply 12.

The rod former 18 is constructed, wi th a forming block 36 and a tongue 37 mounted on the topside of the block 36. The block 36 and tongue 37 form a passageway (not shown) into which connecting rod 28 projects. This latter passageway is sized to receive the tubing 15 passage thorugh the connecting rod 28 and the fibrous filter material 13. The tongue 37 and the forming block 36 are also tapered internally to form an inwardly tapering surface for the passageway so that the passageway gradually diminishes in cross-section. In addition, the rod former 18 includes a conveyor 88 having a conveyor belt 39, such as a continuous fabric belt, which is driven by a belt drive wheel 40 over guide rolls 41 through the passageway formed by the block 36 and tonSue 37. The belt 39 is used to move a stream of porous web 42 e.g. plugwrap paper from a suitable supply reel 43 into the passageway via guide rollers 44 as well as to convey the filter material 13 and tubing stream 15. The web 42 is inherently porous for purposes as explained below.

As shown in Figure 1, the rod former 18 includes a pair of folding sections 46 as are known and heat sealer 48. The folding sections 46 serve to fold the edges of the delivered web 42 towards 44^8 each other in enveloping relationship to the filter material and the tubing while heat sealer 48 heat web 42. Web 42 is impregnated with a thermoplastic material, such as a polyvinyl acetate/polyvinyl chloride copolymer. Upon heating, the copolymer from overlapping web fuses and upon cooling forms a seam.

As shown in Figure 3, fibrous filter material 13 is being constructed by the walls of block 35 to the extent that friction is developed between tubing sections 26 and filter material 13. With a known speed of filter material 13 through block 36, feed rollers 23 and 23‘ advance tubing sections 26 at a slower rate such that tubing sections 26 are it spaced at predetermined intervals along the length 50 of filter rod 11 as shown in Figure 6.

A suitable cutting mechanism utilizing a knife 49 is disposed downstream of lhe sealer 48, as is known, for cutting the completed filter rod 11 into predetermined lengths 50. Each length may thereafter be cut into a multiplicity of filters.

Referring'to Figure 1, in operation, a stream of filter material 13 is fed from the supply source 12, is spread out and decrimped in a conventional fashion as is known and delivered into the nozzle 32. In addition, a length of tubing 15 is taken from the supply reel 14 and connecting passed through cutter 16 into the / rod 19. After the filter material stream 13 is passed into the nozzle 32, the air which is supplied to the nozzle 32 causes the material to bloom, for example, as described in U.S. Patent Specification No. 3,367,447. This allows the fibrous material to be evenly distributed around the tube and to be pushed along copnecting the surface of the /rod 19 into the rod former 18 rather than pulled.

Thereafter, as the filter material 13 is passed into the rod former 18 between the forming block 36 and the tongue 37, the fibrous material is gradually reduced circumferentially due to a tapering of the tcngue 37 relative to the forming block 36. The filter material 13 is then brought a into direct contact with the tubing 15, which has been severed into lengths by cutter 16, within the rod former 18 and is juxtaposed in enveloping circumferential relationship with the tubing 15. At the same time, the web of paper 42 is guided into the rod former 18 underneath the tubing 15 and filter material 13 and folded into a generally U-shape.

Continued travel of the tubing and filter material causes the filter material to be constricted circumferentially about the tubing 15 and to hold the tube lengths 26 in place at spaced intervals along its axial length.

The movement of the fibrous material 13 through the rod former 18 is facilitated by'the conveyor belt· 39‘and the paper web 42 as is known.

In addition, the paper web 42 is subsequently folded about the constricted filter material 13 and the engaged tubing 15 with the paper edges sealed together to form a filter rod 11 of continuous length. The fitter rod 11 is then severed into predetermined lengths 50 by the knife 49.

Knife 49 is programmed to sever filter rod 11 midway between the ends of a selected tube section 26. Figure 6 shows the filter rod 50 and the positions where it is to be severed, i.e. along the lines identified by A, B, C, D and E, in the cigarette making machine. Synchronisation of the cutter position at the desired locations can be facilitated by the use of an electronic scanner. Thus, six (6) cigarette filters are made from one filter rod 5 and each is joined to a tobacco column T to form a filter cigarette as shown in Figure 5. 77 8 Referring to Figure 5, a filter 56 formed from the filter rod 11 includes a hollow cylindrical tube 57 surrounded by an annular layer of compacted filter material 58, a wrapping of perforated Mouthpiece paper 59 and an outer wrap of tipping paper 60. The filter 56 is mounted, as is known, by means bf the outer wrap of tipping paper 60 on a tobacco column T to form a cigarette. The outer wrap of tipping paper 60 is provided with a number of circumferential rows of perforations 61 which are located at about the mid-section of the filter 56.

As shown in Figure 5, the tube 57 is centered on the axis of the filter 56 and forms a passageway 62 from the tobacco column T to diffuser 67 which is' constituted by less compacted filter material, unencumbered by the tube 57.

The smoke (see arrows in Figure 5 for amoke and air path) generated in the burning cigarette cone during the puff upon reaching the filter 56 travels predominantly through the unencumbered passageway 62 in the tubing 57. Upon reaching diffuser 67, the smoke is scattered somewhat but will not be diluted by the air entering through perforations 61 which has filuted the already much filtered smoke which has travelled the full length as indicated by arrow A. Arrow B shows a larger quantity of smoke entering passageway 62. Even though the quantity of this smoke is reduced when compared to normal filter cigarettes, its substantially unfiltered and undiluted state will have the effect of enhancing the taste of the cigarette to the smoker. ‘ The other part of the smoker's puff volume brings in air from the surrounding environment via the perforations 61 in the tipping paper, through the plugwrap paper 59 and the filter material 58 into the smoker's mouth. The air does not mingle with smoke until it is delivered into the smoker's mouth. This enhances the possibility of the smoker getting an increased flavour impression from the delivered smoke stream. In conventional cigarettes utilizing perforated tipping, diluting air and smoke mix within the filter with the delivered smoke stream being prediluted before impinging in the smoker's mouth.

Claims (19)

1. A cigarette filter comprising an open tube defining a passageway extending from one end of the filter which is (in use) placed adjacent the cigarette tobacco for receiving a first portion of smoke, a layer of compacted filter material positioned circumferentially about said tube and extending from adjacent the said one end of the filter beyond the opposite end of the tube to the other (mouth) end of the filter for receiving (in use) a second portion of smoke, and a cylinder of plugwrap about said layer of filter material.

2. A filter tip according to claim 1 wherein said plugwrap is porous paper.

3. A filter according to claim 1 or claim 2 wherein the filter material is less compacted adjacent the mouth end of the filter than about the tube so for dispersing smoke emanating from the tube without significantly filtering it.

4. A filter according to any preceding claim wherein said tube is of polyethylene.

5. A filter according to any preceding claim wherein said filter t material comprises cellulose acetate fibers.

6. A cigarette filter substantially as described herein with reference to Figure 5 of the accompanying drawings.

7. A filter tipped cigarette comprising a tobacco section joined to a filter according to any preceding claim.

8. A cigarette according to claim 7 wherein the filter is joined to the tobacco section by tipping material having a plurality of airconveying perforations. 44*^®

9. A cigarette according to claim 8 wherein the perforations are dimensioned t and positioned so that for a given draw a desired amount of diluted and filtered smoke and substantially unfiltered and dispersed smoke enters the smoker's mouth. 5

10. J A method of making a cigarette filter according to claim 1, . comprising, the steps of: aj providing a first continuous stream of hollow tubing from a - source; b) providing a second continuous stream of fibrous filter 10 material from a source; c) severing said first continuous stream of hollow tubing into predetermined lengths while maintaining said lengths in axial alignment; d) placing said streams in juxtaposition during travel while simultaneously enveloping said second stream of fibrous material 15 circumferentially about said first stream of tubing; e) feeding said length of hollow tubing into said second stream of fibrous material in axial alignment therewith at spaced apart intervals; f) generating a third stream of paper; g) constricting said second stream about said lengths of hollow 20 tubing to frictionally engage said lengths of hollow tubing for continued travel therewith; h) circumferentially enveloping said third stream about said juxtaposed and constricted first and second streams during continued travel of said first, second and third streams to form the filter 25 rod; and i) severing the filter rod. 447 7s

11. A method according to claim 10 wherein the filter rod is first severed into sections consisting of six cigarette filter lengths and subsequently into separate filters.

12. A method according to claim 10 or 11 including the steps of folding opposite edges of said paper stream over each other and adhering said edges together after enveloping said paper stream about said juxtaposed streams to form said filter rod.

13. A method according to claim 10, 11 or 12 wherein said second stream is made of cellulose acetate.

14. A method of making a filter cigarette substantially as described herein with reference to the accompanying drawings.

15. Apparatus for making a cigarette filter according to claim 1 comprising: a) means for supplying a stream of tubing; b) a cutter for receiving and severing said tubing into predetermined lengths; c) a mandrel defining a passageway connecting with said cutter and providing 'passage for said lengths of tubing therethrough; d) tfieans, for supplying a stream of fibrous material; e) means circumferentially enveloping said mandrel for directing said supplied stream of fibrous material circumferentially about said mandrel; f) means extending downstream of said mandrel and being integral therewith for feeding said lengths of tubing into said circumferentially positioned fibrous material in axial alignment therewith and at spaced apart intervals; ΙΟ g) means for supplying a stream of paper; h) forming means for receiving said filter material containing said spaced apart lengths of tubing and paper to circumferentially envelop the paper stream about said juxtaposed streams of filter material and tubing to form a filter rod; and 4) means for cutting said filter rod into predetermined sections.

16. Apparatus according to claim 15 for subsequent subdivision into filters wherein said cutter includes means for forwarding said cut lengths of tubing to said mandrel at a predetermined rate being slower than the rate of flow of said fibrous material through said mandrel whereby said lengths of tubing are fed into said fibrous material at a rate allowing a predetermined distance between said lengths of tubing.

17. Apparatus according to claim 15 substantially as described herein with reference to the accompanying drawings.

18. A filtered cigarette made by utilising a method according to any of claims 10 to 14.

19. A filtered cigarette made by utilizing apparatus according to any of Claims 15 to'17.