US2954773A

US2954773A - Cigarette filters and method of making same

Info

Publication number: US2954773A
Application number: US710780A
Authority: US
Inventors: Herbert A Lebert
Original assignee: Mac Farland Aveyard & Co
Current assignee: Mac Farland Aveyard & Co; Mac-Farland Aveyard & Co
Priority date: 1958-01-23
Filing date: 1958-01-23
Publication date: 1960-10-04
Anticipated expiration: 1977-10-04

Description

Oct. 4, 1960 H. A. LEBERT 2,954,773

CIGARETTE FILTERS AND METHOD oT MAKING SAME Filed Jan. 23. 1958 J /f fh f4 L im 'f 7 TRL-:Lm fllllllllllllli/ 2,954,713 CIGARETTE FILTERS Mnrnon oF MAKINGSAME Herbert A. Lehert, .Millbrae, Calif., assignor to Mac- Farland, Aveyard Company, Chicago, Ill., a cor- `poration of Delaware ,Filed '1mb 2.3., IV19.5.8., Ser. No. 710,180

9 claims. (ci. rs1- 1.0)

The present invention relates lgenerally to .cigarette structures land a method kof manufacturing .the same. More specifically, the j present invention relates to a Ifilter tip construction 4and the vmethod of manufacturing the same whereby the filter tip is provided with a venturi passageway area intermediate its length so that the velocity of smoke passing through the `filter tip may be accelerated and tars in thesmoke may Abe imp'inged upon fibers of the filter tip in a new and improved manner.

The majority of .present day filter-,tip cigarettes use cellulose filaments in varying amounts with various binders and additives. However, in spite ,of lthe manly athousands of fine filaments, the filter tips still have .considerable I space` between the filaments ifor a LrV16" -diameter filter tip bc compressed 'into a 1/s diameter rod or bundle, `that is, a reduction in crossfsect'ional area from approxin rately .07 square inch to .01 square inch or `the equivalent of an -air'passage of approximately .06 squareI inch .or li/gg diameter. Such a large Vair passage in marked con- '-tra'st to the l@ inch or less orifice used to create high velocity-'impingement tar collection according to the principles of my invention as set forth in my earlier filed compending application. In this respect, the present application is a continuationinpart lof my copending applif cation, vSerial No. 662,049, filed May 28, 1,957, for Removal of Tar and Other Deleterious Substances From TobaccoiSrnoke.

It is clear that the conventional filter tips trap -Or col lect such tar as they do stop by virtue of the maze formed by the filaments and the circuitous path the smoke `travels in passing along the length (approximately %6) of the filter tip.

In contrast to the above conventional filter tips ythe same fibrous stranded or cellulose stranded filter tip can be made to `function as a Venturi-impingement tar re-A mover by constricting a narrow zone or section of the filter tip according to certain principles of my 'invention in the present application lso that the aggregate of the air lspaces left through the constricted areaor zone will approximate a gg diameter hole. Then as smoke is drawn through the constricted area or zone it will vbe greatly accelerated and then impinged on the kbarrier formed by the relatively loose packed filament confrontingly .disposed downstream thereof with the tars thereby being extracted.

According to the pres-ent invention the principal object is to' form a critical -s'ized smoke passage or venturi which will speed up ythe Lsmoke `to a terrific velocity exceeding, e.g., onehundred feet per secondso that the heavy (high temperature formed) .tar molecules or particles will not be able to meander their lway through the remaining relativelyr loose packed strands o-f lfilter material', but will, instead, irnpinge against and come to rest on the strands or.filaments of filter tip material that confront or stand in their high speed, straight line path from the'venturi passage. 'Ihe lighter weight aromatic, low temperature -formed smoke particles or fractions which goto make up a safe, enjoyable smoke will change their high speed '2 straight line path to conform to .thedeviousgpaths formed by .the spaces between vthe relatively loosely packed Llilaments that make up the ilter'tip.

Expansion cooling of tobacco smoke requires Yan elongated expansion chamber for the smoke toexpand which 4structure is conventional in the According to -the present invention .the .manufacturing cost .of .the filter tip may be kept to a minimum since the expansion .chamber is not required `and Vthe dimensions ofthe ,conventional v.filter tips ma-y remain substantially unaltered .despite .the inclusion .of .the critical `passage area. lAnother advantage of the present invention is that a standard, .conventional filter tip may be utilized `and its method of manufacture may vbe varied only slightly `so as .toincorporate in Ythe conventional filter tipy the critical .passage iarea as noted above.

l.If the conventional filter tip is Aprovided with a venturi passageway ,area according to Ythe principles of the present invention before it is attached wit-h the cigarette proper, the attaching wrapper or paper will hide the construction so that the finished cigarette will 1appear identi, cal to a conventional filter tip cigarette. This resemblance in appearance is the only similarity, however, since `upon being tested by'the smoker the improved taste will be immediately noted and 'if ,the filter tip is brokenopen after the cigarette has been smoked, the reason for the improved smoke will also be readily apparent in the substantially increased amount of tar accumulation therein.

If the 'filter tip construction 'is manufactured with an ai-r passage area, for example, equivalent to yan .028- .030" diameter hole, all the tars regarded harmful by modern medical thinking will be deposited that is., im` pinged on the filter tip filaments.

The present filter tip construction when comprised of some suitable substance such as cellulose has between its opposite ends an vintermediate fused area with the opposite ends being linked by .the critical vpassageway area through the intermediate fused area. The filter tip fibers downstream o-f the passageway operate as an impingement barrier against which the smoke strikes at velocities exceeding feet per second after passing through the critically passageway area.

The filter-tips may be provided with the critical passageway area by, for example, hot rolling the intermediate portion of the filter tip blank causing the diameter to'be reduced and with the heat fusing the cellulose fibers.`

Accordingly, an object of the present invention is to provide a new and improved highly economical method of manufacturing filter tip elements and filter tip cgarettes.

Still another object of the present invention is to' provide a new and improved filter tip construction which is highly economical.

Yet another object of the present invention is to provide a filter tip construction and method of manufacture which may be carried out so as to enable efficient large scale mass production of the same'.

Other objects and features of the present 'invention will more fully become apparent in View of the following detailed description taken in conjunction with the accompanying drawings illustrating therein a single emmodiment and in which:

.Figure l is a fragmentary cross-sectionall schematic View of my method of manufacturing filter tips for cigawt-tes;

Figure 2 is an enlarged fragmentary crosssect'ional view, partially in elevation, of a fibrous length of filter tip material as shown in Figure 1;;v

Figure 3 lis "an, enlarged fragmentarycross-s'cctioirala view taken substantially on the line III-III; of Figure looking in the direction indicated'by the. arrows Figure 4 is an enlarged fragmentary cross-sectional view of a lter tip according to the principles of this invention;

Figure 5 is an enlarged cross-sectional View taken substantially on the line V-V of Figure 4 looking in the direction indicated by the arrows; and

Figure 6 is an enlarged cross-sectional view similar to Figure 4 only illustrating the filter tip in assembly with tured from any suitable materials such as cellulose, other fibrous materials, and Ithe like. In Figure l a mass of fibrous material 12 is disposed upstream of an extruder mechanism 13 with the fibrous material being actuated or forced through the extruder mechanism 13 in a manner whereby a length or strip 14 of fibrous materials such as cellulose is extruded which strip has a reduced crosssectional dimension.

' Downstream of the extruder 13 is a mechanism 15 for reducing the cross-sectional dimension ofthe strip 14 at predetermined instances along the length of the strip. In the illustrated form the mechanism 15 is suitably shown as a roller ymechanism including rollers 15a and 15b which are preferably heated along with a roller mechanism portion 15e which serves to support the rollers 15a and 15b. This heated roller mechanism serves to constrict the diameter or" the strip and operates to fuse predetermined areas on the strip of material as will hereinafter be described in further detail.

The extruder 13 has a bell-shaped passageway 13a and a spider 16 is mounted within the reduced diameter area of the passageway which spider 16 supports a wire 17 of predetermined critical size.

VEach filter tip includes opposite end portions a and 10b which are separated from one another by an intermediate fused portion 10c which has a reduced crosssectional dimension or area as compared to the opposite end portions 10a or 10b. Extending longitudinally of the reduced intermediate fused portion 10c is a longitudinal passageway area or passage 10d which passage allows smoke to passfrom the upstream end 10b of the filter tip to the downstream end 10a and then into the mouth of the smoker. The opposite end portions 10a and 10b each have annular peripheral fused areas 10e which Voperate to confine the smoke internally of the fused area 10e of the filter tip 10.

Each Vof the opposite end portions 10a and 10b is comprised of a multiplicity of fibers 107 with the fibers on the downstream side of the passageway 10d providing an impingement ba-rrier for the accumulation of tar particles as indicated at T in Figure 6.

According to the method aspects of the present invention, the extruder mechanism operates to extrude a stream or strip of fibrous material having aninternal longitudinally extending passageway 14a created by the wire or rod 17. As the strip of material passes from the extruder roller mechanism 15 constricts the strip forming annular grooves or depressions .leb therein. By virtue of the fact the roller mechanism is heated the peripheral areas of each strip segment 14C is fused. Also, since the roilers 15aF are heated and further since the rollers operate to constrict the material between the segments 14e, link strip portions 14d are internally fused throughout except the area where the passageway 14a extends longitudinally therethrough. Y

Downstream of the extruder mechanism 15 is provided a cut-off mechanism 18 which mechanism operates to cut each of the strip segments 14C in half. It will .be noted the terminal end of the `wire or rod`17V is disposed up-Y n locity of the smoke passing through theffilter tip may 4 stream of the cut-o mechanism 18 to avoid interference therewith. It Will also be noted that since the brous material remains in a flexible relativelyspungy state after each filter tip 10 has been cut from the strip, the portions of the passageway 14a extending the length of the strip sections 14C, or the opposite filter tip end portions 10a and 10b, are closed. i Since the intermediate linking portion of the lter tip is fused, the longitudinal passageway 10d remains therethrough after the filter tips 10 have been cut from the strip 14. I Each of the iilter tips 10 is preferably peripherally sealed in order to preclude the smoke from bypassing the longitudinal passageway 10d and jumping across the gap between the opposite end portions 10a and 10b at the outer periphery of the reduced diametered area 10c. As has beeny discussed above, the filter tip 10 may be heat glazed to fuse the peripheral surface or the peripheral surface of `each of the filter tips may be provided with a coated seal such as by spray painting or the like. In `any event, the linking or intermediate portion 10c should be preferably substantially solid except for the passageway area 10d extending therethrough so the vebe effectively increased.

Each of the filter tips may be suitably provided with a peripheral layer comprised of paper or some :other suitable material which layer is indicated generally at 19 in Figure 6. The peripheral layer 19 as illustrated comprises a tubular member and extends across the depressed area ofthe filter tip so that the iilter may have ya conventional tubular appearance. Eachof the lter tips is then abutted against a cigarette 20 and a paper piece 21 is wrapped around the periphery of the filter tip 10 and the cigarette 20 to connect them together (Figure 6).

In the past, the problem presented has been one of providing sufficient smokeV flow to satisfy the smoker while at the same time removing the deleterious tars,y etc. In the structure of the present invention, this problem is overcome by providing a venturi orilice or passageway which greatly increases the velocity of the smoke stream passing through the iilter tip so that when the stream strikes the barrier comprised of a multiplicity of fibrous Strands such as cellulose, the tar is lodged and collected upon the peripheral surface of the fibrous strands and the resulting purified smoke alters its course through the strands and passes onto the smoker through the downstream end 10a of the filter ytip 10. By referring to the removal of tars the termftars should be regarded `as embracing tars, resins, and other harmful substances. While there will be variations in the size of the orifice, depending upon the character of the smoke, the density of the cigarette mass, etc., in'general eii'ec-` tive results are obtained where the orifice diameter is from .025 to .038 (square inch areas of .0005 to .001). Very satisfactory results have been obtained where the orifice diameter is .028" to .032 (.0006 to '.0008 square inch). As a preferred example, I have` employed effectively an orifice having a diameter of .030 (.0007 square inch), which gives excellent tar removal and ease of drawing. f

i The operation resulting from the structure shown herein is in contrast to the operation of cooling devices heretofore employed with cigarettes where arelatively large `expansion chamber is required. Such cooling devices bring about a peripheral cooling of the smoke but allow substantial core portions of the tars to pass onto the smoker without the tars being removed therefrom. In the present structure, the entire cross-section of the smoke stream is subject to the action of the impingement barrier comprising the downstream end 10a of the lter tip so thatthe Vtars and other harmful particles are removed by the foregoing high velocityimpingement action upon the barrier.

The passageor orifice is effective in greatly increasing the-velocity of the smoke so that it is substantially in excess of 100 feet per second. If more than one orice is used the total square inch area should fall within the range given. In this case the method of manufacture may be altered since one or more additional wires may be sustained within the stream of lter tip material in the formation of the orices or passages in the intermediate fused area c to enable the square inch area to fall within the range given. Of course, the velocity will vary considerably with different smokers and cigarettes of varying degrees of density. By positioning the barrier in confronting relation to the outlet of the orice, the attained high velocity is effective in lodging the tar fractions directly upon the strands of lter tip material thereby removing them from the smoke.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A method of manufacturing lter tips for cigarettes comprising extruding a length of cellulose bers, at selected intervals reducing the diameter of localized areas along the length of cellulose bers by compacting the cellulose bers and fusing the compacted cellulose bers together at the localized area, where the diameter has been reduced forming therethrough a venturi passageway of about .025-.038" diameter, and dividing the length of cellulose fibers into a series of filter tips for cigarettes e'ach having one of the venturi passageways.

2. A method of manufacturing filter tips for cigarettes comprising extruding a stream of cellulose bers, at selected intervals reducing the diameter of localized areas along the stream of cellulose bers by compacting the cellulose bers while contemporaneously setting up internal forces resisting compaction centrally of the stream and fusing the compacted cellulose bers together at the localized area where the diameter has been reduced, forming a venturi passageway having .025".038 diameter through the localized area where the diameter has been reduced, and dividing the stream of cellulose bers into a series of lter tips for cigarettes each having one of the venturi passageways.

3. A method of manufacturing lter tip cigarettes comprising reducing the diameter of a -length of brous material by compacting the brous material constituting a lter tip providing a smoke impervious localized area along the length thereof, contemporaneously setting up internal forces along the length of the area being compressed resisting compression and thereby forming a longitudinal venturi passageway of about .028 to .030 inch diameter extending longitudinally through said localized area of the filter tip for conning a smoke stream to travel at high Velocity therethrough, assembling the filter tip and a cigarette in end-to-end relation, and Wrapping a length of material about the filter tip and the cigarette connecting them together in assembly.

4. A lter tip for cigarettes comprising a strip having `an intermediate smoke impervious portion and opposite peripherally sealed centrally porous upstream and downstream brous end portions on respectively opposite sides of the intermediate portion, and said smoke impervious portion having a single venturi passageway extending longitudinally across the smoke impervious portion linking the brous end portions and of about .025 to .038" diameter and with the venturi passageway operating to accelerate the smoke velocity in excess of 100 feet per second during drawing of smoke therethrough.

5. The lter tip for a cigarette comprising a length of cellulose bers normally related for passage of smoke uniformly throughout its length longitudinally therethrough and with the fibers in a limited area intermediate the length of the filter tip being fused together for thereby providing a fused restriction separating respective unfused portions of the bers on longitudinally opposite sides of thev fused restriction, and said fused restriction having a single orice passageway extending therethrough for passage of smoke, said orice passageway having a square inch cross-sectional flow area of .0005 to .001 for accelerating smoke to pass through the orice passageway at velocities exceeding feet per second during drawing of smoke therethrough, so that tars in the smoke will be impinged upon the unfused bers downstream adjacent to said orice passageway.

6. A yfilter tip as dened in claim 5 comprising in combination therewith a cigarette joined end-to-end thereto, said lter tip having about said fused restriction an annular radially outwardly opening depression, and a wrapper about the periphery of the filter tip and a portion of the cigarette joining them permanently together and concealing said annular depression.

7. A lter tip for a cigarette comprising a length of cellulose fibers with the bers in a limited area intermediate their length being compressed and fused together and with a smoke passageway through the fused bers linking opposite end portions of the filter tip and providing a single hole having a diameter approximating .025"- .038 diameter.

8. In combination, a cigarette and a lter tip in assembly therewith and with the filter tip comprising a length of brous material having a total obstruction intermediate its length except for a single venturi passageway therethrough and with the length of brous material including a brous area on the downstream side comprising an impingement barrier, said venturi passageway being dimensioned for smoke passage therethrough at a velocity in excess of 100 feet per second against the impingement barrier to remove the relatively heavy tars contained in the smoke impinged upon the impingement barrier therebyremoving them from the smoke stream.

9. A method of manufacturing a filter tip for cigarettes comprising reducing the diameter of a length of brous material and thereby by compacting the fibrous material providing a smoke impervious localized area along the length thereof, contemporaneously setting up internal forces along the length of the area being compressed resisting compression thereby forming a longitudinal venturi passageway extending longitudinally through said localized area of the filter tip for conning a smoke stream to'travel at high velocity therethrough and sizing said passageway to a cross-sectional fiow area approximating .025"-.038" diameter.

References Cited in the le of this patent UNITED STATES PATENTS 987,359 Gueniffet et al. Mar. 21, 1911 1,555,320 Weil Sept. 29, 1925 1,616,851 Geisler Feb. 8, 1927 1,983,926 Zirmer Dec. 11, 1934 1,989,130 Brown Ian. 29, 1935 2,246,929 Seney June 24, 1941 2,349,551 Helm May 23, 1944 2,511,898 Brothers June 20, 1950 2,705,013 Brothers Mar. 29, 1955 2,769,533 Booth Nov. 6, 1956 2,794,480 Crawford et al. Jan. 4, 1957 2,780,573 Davidson Feb. 5, 1957 2,820,460 Bunzl lan. 21, 1958 2,869,883 Dunbar Jan. 20, 1959 FOREIGN PATENTS 188,091 Germany Ian. 27, 1907

Claims

1. A METHOD OF MANUFACTURING FILTER TIPS FOR CIGARETTES COMPRISING EXTRUDING A LENGTH OF CELLULOSE FIBERS, AT SELECTED INTERVALS REDUCING THE DIAMETER OF LOCALIZED AREAS ALONG THE LENGTH OF CELLULOSE FIBERS BY COMPACTING THE CELLULOSE FIBERS AND FUSING THE COMPACTED CELLULOSE FIBERS TOGETHER AT THE LOCALIZED AREA, WHERE THE DIAMETER HAS BEEN REDUCED FORMING THERETHROUGH A VENTURI PASSAGEWAY OF ABOUT .025"-.038" DIAMETER, AND DIVIDING THE LENGTH OF CELLULOSE FIBERS INTO A SERIES OF FILTER TIPS FOR CIGARETTES EACH HAVING ONE OF THE VENTURI PASSAGEWAYS.