US2793572A

US2793572A - Apparatus for and method of making filters

Info

Publication number: US2793572A
Application number: US285686A
Authority: US
Inventors: Harris B Parmele
Original assignee: P Lorillard Co
Current assignee: P Lorillard Co
Priority date: 1952-05-02
Filing date: 1952-05-02
Publication date: 1957-05-28
Anticipated expiration: 1974-05-28

Description

y 1957 H. B. PARMELE APPARATUS FOR AND METHOD OF MAKING FILTERS 3 Sheets-Sheet 1 Filed May 2, 1952 idila-ssmlitaif FIG. I.

INVENTOR:

HARRIS B. PARMELE May 28, 1957 H- B. PARMELE APPARATUS FOR AND METHOD OF MAKING FILTERS 3 Sheets-Sheet 2 Filed May 2, 1952 6 HARRIS B P A FQ JQ S:

May 28, 1957 PARMELE APPARATUS FOR AND METHOD OF MAKING FILTERS 3 Sheets-Sheet 5 Filed May 2, 1952 J B F INVENTOR:

HARRIS B. PARMELE r 05 ATTORNEYS.

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United States Patent APPARATUS FOR AND METHOD OF MAKING FILTERS Harris B. Parmele, Glen Ridge, N. J., assignor to H & V Specialties Co., Inc., a corporation of Massachusetts, and P. Lorillard Company, a corporation of New Jersey, jointly Application May 2, 1952, Serial No. 285,686

3 Claims. (Cl. 93-11 This invention relates to respiratory filters, and has particular reference to filter units for tobacco products, such as cigarettes, and to methods and apparatus for making the same, although the invention is not limited thereto.

Numerous types of filters for cigarettes, smoking pipes, cigarette holders, gas masks, surgical respirators and other devices through which air is drawn by the user have been used or proposed, but in most instances, the cost of manufacture and the eifecti-veness of the filters leave much to be desired. Particularly in the case of tobacco smoke filters for cigarettes and the like, the effort has been to reduce the quantity of volatile materials, principally tar, en trained in the tobacco smoke. In order to be sufficiently effective to remove a substantial quantity of tar, the filter had to be made so dense as to increase the suction to an undesirable degree to draw the smoke through the filter and cigarette. Consequently, incomplete filters or filters having channels or passages were provided, with the result that the filter was ineffective to remove more than a small percentage of tar which was substantially only that which condensed on the surfaces through which the smoke was drawn.

Effective filtering material for removing predetermined quantities of tar and also nicotine from tobacco smoke drawn through a cigarette or other smoking article has been provided, one example being disclosed in copending application Serial No. 260,187, filed December 6, 1951 (now abandoned), by Harold W. Knudson, disclosing filtering material comprising fibrous material, such as cotton, containing a predetermined, uni-form distribution of mineral particles having dimensions approaching those of the smoke particles to be removed, so as to cooperate with the cotton to remove a predetermined proportion of the smoke particles. Notwithstanding the pronounced. effectiveness of this filtering material, its advantage in a cigarette filter unit still depends on uniform density throughout the cross-sectional area of the filter unit without any channels or other passages permitting the smoke to shortcircuit the filtering material. The same requirements obtain for other filter units.

In accordance with the present invention, a respirator type of filter unit and a method and apparatus for making the same are provided, whereby smoking articles or other respirator products embodying or containing the filter I 2,793,572 Patented May 28, 1957 are interleaved in such a way that the crepe paper layers, each supporting a cotton layer, are laid one upon the other and the sandwich thus formed is supported on the nethermost crepe paper layer so that the upper surface of the sandwich layer is a cotton layer. This sandwich-like sheet is fed to a plug-making machine while carried on the nethermost layer of crepe paper, but just before entering the machine, the nethermost layer of crepe paper is stripped therefrom, so that the upper and lower layers of the sheet are cotton. Narrow strips are severed transvcrsely from this composite sheet and fed endwise to a conical forming die, but before reaching the die, the strip is creased off-center lengthwise, so as to then fold unevenly upon itself in the conical forming die, i. e., because of the off-center crease, one leg of the infolded strip is wider than the other, so that the edges thereof do not register. When rolled into generally J-shaped contour in the forming die, the non-registering edges of the strip do not leave a passage at the core and, with the aid of cottonto-cotton contact at that point, the resulting plug is of uniform cross-sectional density. The rope-like strip is then Wrapped in paper and severed into shorter lengths, which are then incorporated in a cigarette, used as a cartridge for smoking pipes, cigarette holders or other smoking articles, or as cartridges for gas masks, surgical respirators, and the like.

it will be seen that the filter unit and the method and apparatus of making the same provide a filter unit of uni- 1 form density and draw, not-withstanding the numbers that may be manufactured.

For a more complete understanding of the invention, reference may be had to the accompanying drawings, in which:

Figure 1 is an elevation of apparatus for laminating three sets of paper overlaid with a web of fibrous material, such as cotton;

Fig. 2 is a transverse section as seen along the line 2 of Fig. 1, showing the laminate formed in Fig. 1, and comprising three alternate layers of paper and cotton 'with the entire sandwich-like laminate supported on the lowermost paper layer;

Fig. 3 is an elevation of the mechanism for feeding the laminate or sandwich of three alternate layers each of cotton and paper through successive processing stagesand showing the edge-trimming mechanism, intermittent feeding mechanism, mechanism for stripping the lowermost sheet of paper from the sandwich or laminate, and the mechanism for severing the sheet transversely .into long,

- narrow strips;

Fig. 4 is a schematic plan view of the mechanism of Fig. 3 with the addition of conical forming mechanism for shaping the long, narrow strips into a rope-like shape,

wrapping the same and severing it into filter units;

unit are uniform in density and draw to afford the same Fig. 5 illustrates the conical forming die of Fig. 4 as it appears on a commercial machine as modified to embody the present invention;

Fig. 6 is an elevation thereof as seen along the line 6-6 of Fig. 5; Fig; 7 is a transverse section through the strip creasing roll and the carrier tape for the strip as seen along the line 7-7 of Fig. 6 and showing the off-center relation between the creasing roll and the laminated strip; Fig. 8 is a transverse section through the formingdie as seen along the line 8-8 of Fig. 6;

Fig. 9 is a transverse section through the grooved pressing roller constituting part of the forming mechanism as seen along the line 9-9 of Fig. 6;

' Figs. 10A, 10B and 10C are cross-sections through theilaminated strip in successive stages ofmits formation into the rope, and shows the convolutions of alternate layers of paper and cotton and the result of the cottonto-cotton contact at the center or core without channels and the off-center creasing of the strip preceding its entry into the conical forming die; and

Fig. 11 illustrates in perspective form a stationary type of strip creasing or folding device.

Referring to Figs. 1 and 2 of the drawings, the cot ton or other fibrous material C with or without admixture of the mineral particles according to the aforementioned Knudson application, is laid uniformly as a thin but continuous web upon a sheet of paper P, such as crepe paper whose creases or crepe folds extend transversely thereof. The cotton web may be conveniently supplied by a commercial carding machine in a width somewhat narrower than the width of the crepe paper sheet P, so that about a half inch margin of paper extends beyond the lateral edges of the cotton web C, as shown in Fig. 2.

In the preferred filter unit of this invention, three layers of cotton and three layers of paper comprise the starting laminate or sandwich and are initially interleaved from three primary supply rolls 10, 11 and 12, rolls 11 and 12 each comprising one long sheet of crepe paper P overlaid by one layer of cotton C, and roll '10 comprising one long sheet of strong paper P, such as kraft paper, overload by one layer of cotton C. Layer P also may be crepe paper if desired.

The three primary supply rolls 10, 11 and 12 are simultaneously unrolled with the unrolled portions of each overlying the unrolled portion of the others in the manner shown in Fig. 1, so as to form the laminate or sandwich S comprising three alterenate layers each of paper and cotton, with the nethermost layer being paper and the topmost layer being cotton, as is shown especially in Fig. 2.

The primary supply rolls 10, 11 and 12 are mounted on mandrels journalled in a suitable frame, not shown. A driven endless belt conveyor 13 may support the laminate or sandwich S and may drive it and thus 'unroll rolls 10, 11 and 12 by frictional contact therewith, with the laminate or sandwich S. In this way, the separate twolayer strips are unrolled from the primary supply rolls 10, 11 and 12 upon a main supply roll 14 in step with each other and roll 14, so that the cotton C and the paper P are not materially strained or stretched. The main supply roll 14 may be driven if required. Suitable mechanism according with Fig. 1 and performing the equivalent function is disclosed by Aivaz Patent No. 1,856,- 823, dated May 3, 1932.

Main supply roll 14 is transferred from storage or from the machine of Fig. 1 to the machine of Fig. 3 for unrolling onto table 15 thereof. Alternatively, the 1aminate or sandwich S may be fed by conveyer 13 directly to the horizontal table 15 of Fig. 3. Assuming the transfer of the storage roll 14 to the machine of Fig. 3, the former is unwound flatwise on the table 15 in any suitable way, as by driving its mandrel from an intermittent drive mechanism including a source of power such as the electric motor 16 shown in Fig. 3, whereby the feed of the laminate or sandwich S is synchronized with the intermittent plug-making machine to be described. The unwinding of the roll 14 is so regulated as to maintain a uniform linear rate of movement of the sandwich or laminate S over the table 15. One example of a convenient mode of accomplishing uniform unrolling of a large storage roll, such as 14, is disclosed in Aivaz Pattent No. 1,993,728, dated March 12, 1935.

As the laminate or sandwich S is advanced over the table 15, the margins of crepe paper extending beyond the lateral edges of the three webs of cotton C are trimmed ff in any suitable manner as by rotating knives 17, driven by belt or chain 18 from the mandrel of roll 14 or otherwise in the manner shown in Figs. 3 and 4. Accordingly, the sandwich or laminate S comprises alternate layers of paper P and cotton C of uniform width. The edge-trimmed sandwich S is engaged by a driving roll 19, driven by chain or belt 20, which aids in drawing the sandwich S through the edge-trimming knives 17 and in advancing the sandwich S along the table 15, this driving roll being positioned just beyond the edge-trimming knives 17 as shown in Figs. 3 and 4.

Positioned just beyond the driving roll 19 and 1ocated in a slot in the table 15, is idler roll 21 over which the nethermost layer P of paper moves downwardly and is thus separated from the lower cotton layer which now takes the place of the separated paper layer P by which the sandwich S was theretofore supported on the table 15. The separated paper layer P is drawn onto takeup roll 22 suitably driven by a belt or chain 23 at the proper peripheral speed .to obtain uniform movement of the sandwich 5 across the table 15 and take-up roll 22 aids in that movement. Thereupon the sandwich or laminate 5 comprises two layers of paper P and three layers of cotton C with the upper, lower and center layers being cotton interleaved by the two remaining layers of paper.

From this point, the five-layer sandwich or laminate S resting on transverse platform 24 is advanced intermittently by reciprocating pushers 25 actuated by oscillating shaft 26 preferably driven and constructed in the manner shown in Ruau Patent No. 2,145,528 which generally illustrates a suitable commercial machine for the manufacture of filter plugs or wads for cigarettes and which has been modified to embody the present invention to manufacture the novel cigarette filter units or filter units for other respiratory purposes according to this invention. Details of the plug-making machinery utilized in part for making the filter units of this invention may be had upon reference to said Ruau patent,

except in so far as the mechanism thereof has been modified in the manner to be described. Only so much of the mechanism of the Ruau patent is disclosed herein as is necessary to an understanding of the present invention.

The pushers 25 shown in Fig. 3, advance the five-layer laminate sandwich S beneath a reciprocating knife 27 which severs it transversely into narrow strips 28 which may be on the order of 1 /2 inches in width and 26 inches in length, for example. The severed strips 28 lodge in a channel 29 in which they are advanced endwise by reciprocating gripping means shown in said Ruau patent to the belt type conveyor shown in Fig. 6, and comprising an endless belt 30 running over a pair of rollers 31 journalled in a horizontal plane so as to provide a horizontal conveying surface between them. The belt 30 also passes over a series of rollers 32, one of which is driven to drive the belt 30 in the proper direction from right to left, as seen in Fig. 6.

Positioned above the right-hand or infeed end of the belt 30 as seen in Fig. 6, is a feed roller 32' which is driven in the direction of movement and peripheral speed by and in accordance with the linear speed of the belt 30 and presses the laminated strip 28 against the belt 30 for advancement thereby to the left, as seen in Figs. 5 and 6.

Immediately following feed roller 32 and also driven by the belt 30 through the laminated strip 28 is the offcenter creasing or folding roller 33, whose center line is displaced laterally with respect to the longitudinal center line of the laminate strip 28 by approximately 4 inch, as is shown particularly in Figs. 3 and 7. By reason of its off-center position with respect to the strip 28, the rounded periphery of folding or creasing roller 33 folds or creases the strip 28 uneven-1y, lengthwise, i. e., the left-hand portion of the strip 28 as seen in cross-section in Figs. 7, 8 and 10A, is longer transversely than is the right-hand portion thereof. Hence, as the edges of the strip 28 rise in response to the folding and creasing .action of the roller 33, the left-hand edge rises higher than the right-hand edge so that the strip 28 has the uneven trough-shaped cross-section shown in Figs. 7 and 10A. Thus, if the two sides of the strip 28 are folded fiatwise upon each other, the lateral edges would not be in registry as is shown in Fig. 10B.

Positioned at each side of the roller 33 are channelshaped guides 34 which are upturned to accommodate and aid the tendency of the edges of the strip 28 to turn upwardly in the manner described. To compensate for the longer left-hand side of the strip, the left-hand guide 34 is longer and extends further from the center line of the feed belt 30 as is likewise shown in Fig. 7. Conversely, the right-hand guide 34 is shorter and lies somewhat more closely to the center line of the belt 30 to accommodate the shorter half of the strip 28 as seen in cross-section.

As the feed belt 30 carries the strip 28 through the guides 34, it enters the conical forming die 35 at a time when the lateral edges of the strip 28 have been lifted to shape it into a reversed J-shaped cross-section with the lefthand leg thereof longer than the right-hand leg thereof for the reasons mentioned. Accordingly, as the J-folded laminated strip 28 enters the conical forming die 35, which is a continuation of the guides 34, the offset edges are curled downwardly upon one side of the center portion which then takes the convoluted shape shown in Fig. 100.

As the folding strip 28 advances, the concavity of the surface of the roller 36 which cooperates with the concave upper roller 37, the belt 30 is warped into a U-shape to aid in circumferentially confining the strip 28 into the rope-like contour 28' shown in Fig. 9. Accordingly, the strip 28 is confined circumferentially into a generally circular cross-section with the cotton-to-cotton contact between the original cotton upper surface and the original cotton lower surface of the strip 28 and between the same cotton surfaces folded upon each other, thereby precluding or closing all passages which tend to form, and aided by the misalignment of the edges of the strip 28 so that uniform density results.

The rope emerging from between guides 38 is delivered immediately to the wrapping station where a strip 39 of cigarette paper, for example, is concurrently fed from reel 40 shown in Fig. 4 and wherein the rope 28' is wrapped in the manner described in said Ruau patent, and the seam heat-sealed with glue or cement at 41.

The successive strips 28 are aligned end-to-end as they are shaped into the circular cross-section shown in Figs. 9 and 10C, and are wrapped in the paper from reel 40 so that a continuous wrapped rod 42 emerges from the machine to be severed into approximate 2% inch lengths 43 by the flying knife 44 in the manner shown in said Ruau patent. The cylindrical lengths 43 having the transverse joint formed at the juncture of successive strips are culled out by removal of every tenth, and the remaining lengths are then subdivided into shorter lengths, incorporated in the end of a cigarette in a cigarette-making machine to become part of the cigarette.

The off-center folding or creasing of the strip 28 to achieve the uneven folding of the edges upon each other may be eifected by other means than the roller shown in Fig. 7. For example, the stationary vertical blade shown in Fig. 11 will perform the folding function of the roller 33 or other equivalent mechanism.

In its passage through the conical forming die 38, the trough-shaped but unevenly-folded strip 28 assumes convolutions which delineate a shape somewhat like a pear with the narrow end continued into a curve, and close variants thereof. In any event, the cotton-to-cotton contact together with the misalignment of the lateral edges preclude the formation of channels or passages through which the smoke or other gaseous material may shortcircuit the filter material and thus remain untreated.

Although the off-center folding of the laminate strip to misalign the opposite edges thereof upon formation into a rope is preferred, foldingof the strip along its center line into U-shaped cross-section in the manner effected by the machine of said Ruau patent nevertheless still provides filter units which are satisfactory for many purposes, because of the cotton-to-cotton contact afforded by the greater number of cotton layers as compared to the one less number of paper layers, e. g., two-to-one, respectively, to morethan three-totwo, respectively, e. g., five-to-four, respectively, depending upon requirements.

Similar mechanisms may be provided for forming filter units of different dimensions according to the method of this invention for use as gas mask or surgical respirator filter cartridges and the like, as well as filter cartridges for cigarette holders, smoking pipes, and the like.

The term cotton as used herein means any suitable natural or synthetic textile fibers capable of being formed into a thin, pervious web, and the term paper as. used herein means any suitable sheet material having the properties described herein and generally substantially impervious to the passage of gases and vapors.

Although preferred embodiments of the filter unit and method and apparatus for making the same have been illustrated and described herein, it is to be understood that the invention is not limited thereto, but is susceptible to changes in form and detail within the scope of the appended claims.

I claim:

1. The method of making filter units, which comprises alternately interleaving a plurality of layers of pervious fibrous material with one less layer of substantially impervious sheet material to form a multiple-ply laminate with layers of said fibrous material forming its opposite, outer surfaces, longitudinally folding an elongated strip of said laminate into a trough shape with the fibrous material on the inside and the outside of said troughshaped strip, circumferentially confining the trough-shaped strip to form a rope of substantially circular cross-section having an outer surface layer of said fibrous material, wrapping the rope in sheet material to form a tubular cover therefor, and transversely severing the covered rope into cylindrical plugs for use as filter units.

2. The method of making filter units, which comprises laminating a plurality of sets of a pervious web of fibrous material carried on a sheet of substantially impervious sheet material to form a multiple-ply laminate consisting of an equal number of said webs and sheets supported on the nethermost sheet, stripping the nethermost sheet from the laminate to provide a laminate comprising top and bottom webs of fibrous material and at least one interleaved sheet, longitudinally folding an elongated strip of said last-named laminate into a trough shape, circumferentially confining the trough-shaped strip to form a rope of substantially circular cross-section, wrapping the rope in sheet material to form a tubular cover therefor, and transversely severing the covered rope into cylindrical plugs for use as filter units.

3. In apparatus for making filter units, the combination of a source of a plurality of sets of a pervious web of fibrous material carried on a sheet of substantially impervious sheet material, means for lapping a plurality of said sets to form a multiple-ply laminate consisting of an equal number of said webs and sheets supported on the nethermost sheet, means for stripping the nethermost sheet from the laminate to provide a laminate com prising top and bottom webs of fibrous material and at least one interleaved sheet, means for longitudinally folding an elongated strip of said last-named laminate into a trough shape, means for circumferentially confining the trough-shaped strip to form a rope of substantially circular cross-section, means for wrapping the rope in sheet material to form a tubular cover therefor, and means for transversely severing the covered rope into cylindrical plugs for use as filter units.

(References on following page) 7 References Cited :in-the file of :this patent UNITED STATES PATENTS 8 Alley May 23, 1939 Davidson 'July 4, 1939 Davidson Nov. 12, 1940 Sebox et a1 Feb. 26, 1952 FOREIGN PATENTS Netherlands Aug. 16, 1933 Great Britain Oct. 28, 1935 MW M W."