US3053259A - Processing tobacco - Google Patents

Description

Sept. 11, 1962 H. B. PARMELE ETAL 3,053,259

PROCESSING TOBACCO Filed April 22, 1958 2 Sheets-Sheet 1 INVENTORS HARRIS B.PARMELE FRANK B.DOYLE 8s BY WILLIAM E.ROUTH Sept. 11, 1962 H. B. PARMELE ETAL 3,053,259

PROCESSING TOBACCO Filed April 22, 1958 2 Sheet 2 INVENTORS HARRIS a. PARMELE FRAN a. DOYLE a BY WILLI E. ROUTH Ir A 7'TOR/VEYS.

3,053,259 PROCESSING TOBAUCO Harris B. Parmele, Glen Ridge, N.J., Frank B. Doyle, Raymond, Ill., and William E. Routh, Greensboro, N.C., assignors to P. Lorillard Company, New York, N.Y., a corporation of New Jersey Filed Apr. 22., 1958, Ser. No. 730,155 4 Claims. (Cl. 131140) This invention relates to processing tobacco and has particular reference to methods and apparatus for reclaiming fragmented tobacco or tobacco fines, converting the same into equivalent tobacco shreds and blending the same with cut tobacco for manufacture into cigarettes or other smoking tobacco products.

It is well known that a considerable percentage of fragmented leaf tobacco or fines results from the normal processes of stemming, drying, casing, cutting and blending leaf tobacco to a form suitable for the manufacture of cigarettes and other tobacco products. These tobacco fines are high quality tobacco material and, if recoverable and convertible without substantial change into usable form, would improve many tobacco products as well as resulting in a considerable saving of valuable material which would otherwise be wasted or utilized as components of agricultural fertilizers and pesticides.

Many proposals have been advanced for the reconstitution of tobacco in various usable forms, but virtually all of them include a change in the characteristics of the tobacco, usually caused by the addition of a substantial percentage of gum adhesives needed to bind the finelydivided tobacco particles in molded or sheet form in simulation of a stripped tobacco leaf for use as a cigar wrapper, for example, or cut into ribbons for blending with cigar or cigarette filler tobacco.

In accordance with the present invention, a process for reclaiming and converting tobacco fragments or fines resulting as a by-product from cigarette and cigar making processes substantially directly into tobacco shreds suitable for blending with tobacco is provided, without the necessity of first forming the reclaimed tobacco into sheets and then cutting or slicing the same into properlysized material for cigarette manufacture and the like.

In a preferred process of the invention, the tobacco fragments or fines which are collected as a by-product of the cigarette and cigar making processes are first screened to remove sand and other fine foreign particles, the resulting cleaned tobacco fines are ground or otherwise comminuted into particles of predetermined size, the ground material is again screened to reject undersize particles and oversize particles are recycled to the grinding stage. The ground tobacco of the proper size is then impregnated with an aqueous solution humectant, sugar, and a suitable binder. The impregnation is conducted under such conditions that the solution is dispersed through the interior of the tobacco particles so that the impregnated material does not feel moist, cannot be balled in the hand and resembles wood sawdust, although it may contain as high as 40% water.

The granular tobacco mixture is fed to the valley between two contacting driven rollers, one of which is smooth-surfaced and the other is circumferentially slotted or grooved. The rollers are held in tangential engagement with sufficient pressure so that the tobacco is confined to and compressed within the grooves or slots and is thus compacted into discrete strings or shreds having lengths not less than about one inch and up to six inches or longer. The shreds so formed are then dried to remove moisture down to about 20% and admixed with cut tobacco from the natural stripped leaf in a proportion on the order of 1 to 20% by weight for manufacture into cigarettes or other smoking tobacco products in the usual way.

It Wil lbe seen that the process and apparatus of this invention provide an elficient and economical way of reclaiming high quality by-product tobacco fines and utilizing them to improve the finished smoking article such as a cigarette.

A more complete understanding of the invention may be had by reference to the accompanying drawings, in which FIGURE 1 is a flow diagram illustrating the tobacco reclaiming process and apparatus of this invention;

FIG. 2 is a plan view of the tobacco compacting and shred-forming mechanism of this invention;

FIG. 3 is an end elevation thereof as seen along the line 33 of FIG. 2; and

FIG. 4 is an enlarged fragmentary section through the grooved or slotted roller as seen along the line 44 of FIG. 3.

Referring to the flow diagram of FIG. 1, numeral 10 designates one of the boxes in which the tobacco fines such as dust, stems, conveyor siftings and the like are collected as by-products from the cigar, cigarette and other tobacco product manufacturing processes. Before being loaded into the boxes 10, the fines are passed over an mesh per inch screen to remove sand and other heavy fine foreign particles. The boxes 10 are mounted on dollies or fitted with casters, wheels or rollers and conveyed to and emptied into a receiving hopper 11. The suction pipe 12 of a pneumatic conveyor 13 driven by a fan 14 carries the tobacco fines to one or more storage bins 15. Preferably, there are a number of such bins 15, each receiving and storing a different type of material. Thus, one bin 15 may receive only by-product tobacco fines from a hopper 11 supplied by a box 10 from the stemmery, another bin 15 may receive only shorts, another conveyor siftings, and so on.

The bottom of each bin 15 is provided with an individual rotary motor-driven proportioning feeder 16, which deposits a predetermined amount from each bin 15 on a belt-type conveyor 17. By preselecting the feeders 16 and their rate of discharge, the proper blends of materials from the several bins 15 may be provided.

The conveyor 17 discharges into a hopper 18 having a float switch 19 which actuates a switch shutting off the driving motor 20 of the conveyor 17 when the hopper is filled and restarts the motor 20 when the level of the material in the hopper 13 drops below a predetermined point. In a manner readily understood the float switch 19 may similarly control the driving motor of any feeder 16 that is in operation at the time the hopper 18 is filled or empty in order to preclude excessive accumulation of material on the conveyor 17 when it is stationary.

The hopper 18 is provided with a motor-driven proportioning feeder 21 similar to feeders 16 for delivering the material to a belt flow-scale 22. of known construction and adjusted to control the speed of feeder 21 so that a predetermined weight of material per minute is fed by flow-scale 22 to the multi-stage motor-driven grinder 23'.

Grinder 23 may be a hammer mill, ball mill, or impact mill, and mixes and grinds the tobacco material to a size such that it passes through a screen of 60 mesh per inch with about 80% smaller than mesh, so that the ground material discharged from the mill 23 is finely-divided but not powdered. This finely-divided material is drawn from the last stage of the mill or grinder 23 to storage bin 24 by the suction pipe 25 of a pneumatic conveyor 26 driven by fan 27.

As it is required, the finely-divided tobacco material is fed to flow-scale belt 29 by a motor-driven proportioning feeder 28 similar to the feeder and flow-scale combination 21, 22 previously described. This measured material is fed by belt 29 to the hopper of motor-driven mixer 30 where it is mixed with an aqueous solution or mixture of binder and humectant supplied from tank 31 by pipe 32 at a predetermined rate controlled by valve 33.

Several forms of aqueous binder and humectant mix tures or solutions may be provided in tank 31. For example, it may be a mixture of 85 parts of sodium salt of carboxymethyl cellulose (CMC), 7.5 parts of the sodium salt of carboxymethyl-hydroxyethyl cellulose (CMHEC), 7.5 parts of guar gum. The CMC, CMHEC and guar gum are added together in a dry form and mixed thoroughly in a twin-shell blender. The binder mixture is added to the sugar-humectant solution which has been heated to 85 C. The sugar-humectant solution consists of 6.45 parts of Nulomoline (inverted sugar solution), 3.85 parts of glycerine, 0.65 parts of propylene glycol, 0.01 part of methyl-p-hydroxybenzoate (MPHB), and 89.04 parts of water. Six pounds of dry binder are added to 154.0 pounds of sugar-humectant solution. This binder-sugar-humectant solution has a viscosity of about 36,000 centipoises at 69 C.

Another suitable aqueous binder and humectant solution comprises 50 parts of corn starch and parts of the above sugar-humectant solution mixed with 200 parts of water. The resulting binder-sugar-humectant solution has a viscosity of about 36,000 centipoises at 69 C.

About 160 pounds of either binder-sugar-humectant solution from tank 31 are fed to mixer 30 together with 190 pounds of the powdered tobacco material and 10 pounds of cellulose fibers, which are added to flow-scale 29 with the tobacco from feeder 28. The cellulose fibers may be alpha-cellulose flock, shredded cigarette papers, or other substantially ash-free natural or synthetic fibers which are odorless and nontoxic when burned.

The resulting mixture consists of tobacco particles surface-coated with the binder-sugar-humectant solution but not materially impregnated therewith. Thus, the tobacco material is damp with the solution but it is not wet or doughy, but is more dry than wet so as to be readily fluent or flowable. This mixture is discharged from mixer 30 through pipe 34 leading to dispersing machine 35, which contains a motor-driven beater-screw or propeller 36, and may be a pressure muller, vacuum impregnator, pug mill, extrusion apparatus, or a high speed centrifugal mixer, examples of which are marketed under the trade names Votator, Entoleter, etc. The machine 35 accordingly impregnates or introduces the surface-carried binder-sugar-humectant solution into the interior of the tobacco particles which initially had a moisture content of about 8 to about In some instances the dispensing machine 35 will make premixing in mixer 30 unnecessary.

The resulting tobacco material discharged by machine 35 to suction pipe 37 is a homogeneous flowable mixture of solid tobacco and binder-sugar-humectant solution containing about 30 to about 40% water, but it does not feel moist to the touch, cannot be balled in the hand and somewhat resembles slightly damp wood sawdust.

The suction pipe 37' of the pneumatic conveyor 38 driven by fan 39 conducts the dispersed fluent tobacco material to a storage bin 40 from which it is metered by motor-driven proportionary feeder 41, similar to feeder 16, to the suction pipe 42 of a pneumatic conveyor system driven by fan 43 for supplying storage containers 44. Storage containers 44 are shown schematically in FIG. 1 as comprising a series of closed chambers 45, nine being shown, but there may be more or less depending upon requirements. Each chamber 45 is normally closed by a valve 46 and is filled with the fluent material from storage bin 40.

When one of the valves 46 is opened, and with valve 47 in eduction pipe 48 closed, the contents of the chamber 45 corresponding to the opened valve 46 are discharged into storage bin 50 through pipe 51. Similarly, other chambers 45 may be evacuated to bin 50 by opening the corresponding discharge valve 46. This may be done manually, but preferably it is done automatically by means of a float switch 52 in bin 50 and responding to drop in the level of material in bin 50 to open a valve 46 electrically and reclose it when the level in bin 50 rises to a predetermined height. The valves 46 may be connected in parallel with float switch 52 so as to operate individually as required or a separate bin 50 and float switch 52 for each storage chamber 45 may be provided, depending upon the volume of stored material to be handled.

When all valves 46 are closed and the corresponding chambers 45 filled, valve 47 is opened automatically and the dispersed material from storage bin 40 is returned thereto via pipes 42 and 48. When the pressure at the feeder 41 exceeds atmospheric, weighted valve 53, normally closing discharge pipe 54 from fan 43, opens and vents excess air and any entrained material to the dust house, not shown, and to which the exhaust of fans 14, 27 and 39 also are connected.

A regulated flow of the impregnated tobacco material is supplied from storage bin or bins 50 by a motor-driven proportionary feeder 55, similar to 16, to a belt type flow-scale 56, similar to flow-scale 22, and whose flow rate is so adjusted to hopper 57 that the valley between rollers 58 and 59 is maintained level filled.

Referring now to FIGS. 2, 3 and 4, showing the rollers 58 and 59 in enlarged scale with their accompanying mechanism, it will be seen that roller 58 is journalled in fixed bearings 60 mounted on a suitable base plate casting 61 and that roller 59 is journalled in arms 62 pivoted at 63 on base casting 61. Pivoted arms 62 and consequently roller 59 are urged toward roller 58 by strong coiled tension springs 64 so that roller 59 engages roller 58 with considerable pressure for a purpose to be described. Alternative pressure means, such as hydraulic cylinder and piston combinations or compression springs and the like may be employed to urge rollers 58 and 59 together instead of the tension springs 64.

As is shown particularly in FIG. 2, roller 58 is grooved or slotted circumferentially and preferably is of larger diameter than roller 59, which is smooth surfaced. The surfaces of rollers 58 and 59 preferably are made of surface-hardened steel and are accurately machined so that the ridges, ribs or lands 65 that are formed between the circumferential slots or grooves 66 engage the smooth surface of smaller roller 59 at the line of tangential contact between them so as to confine the tobacco material fed between the rollers from hopper 57 to the grooves or slots 66 without permitting any of it to enter between the lands 65 and the contacting surface of smooth roller 59. This confining and limiting action is not only provided by the sharply-defined lands 65 but also by the considerable pressure with which the rollers 58 and 59 are forced together by the springs 64, with the result that the tobacco material is laterally or transversely compacted in the slots or grooves 66 as distinguished from the axial or longitudinal compaction effected by an extrusion process. The tobacco material is accordingly formed with the aid of the sugar-binding-humectant content thereof, into elongated strings or shreds 67 which are sufliciently strong to be self-sustaining to a substantial degree, such that they break off into lengths not less than about one inch and up to about six inches or longer as they fall by gravity from between the rollers 58, 59, as is shown in FIG. 3.

The cross-sectional dimension or diameter of the shreds 67 is largely determined by the use to which they are to be put. If they are to be blended with cut tobacco for cigarette manufacture, they are of substantially corresponding dimensions. Thus, it has been found that an axial width of about .033 inch and a radial depth of about .006 to .020 inch is satisfactory depending on the end use. A generally rectangular cross-section for the groove or slot 66 has been found to be satisfactory, although for uses such as for smoking tobacco or cigar filler blending, larger dimensions and a different shape of slot or groove cross-section, such as V-shaped or semicircular, for example, may be required.

The width of the ribs, ridges or lands 65 should be as narrow as possible for optimum output of the machine, but because of the considerable pressure with which the rollers 58 and 59 are held together, they must be sufficiently wide to preclude grooving the smooth roller 59 and strong to withstand being distorted. Thus, a land width of about .017 inch has been found to be a satisfactory minimum dimension for manufacture of cigarette blending shreds, although that dimension may be increased as desired and where lower pressures are used, may be decreased slightly. With these dimensions, the proper pressure should be such that the rollers cut thin paper, e.g., cigarette paper, to shreds.

As shown in FIGS. 2 and 3, the grooved roller 58 is fitted with a spur gear 68 driven by spur gear 69 from a suitable source of power like an electric motor, not shown. Smooth roller 59 is not driven except by friction from grooved roller 58, so that both rollers 58 and 59 rotate at the same peripheral speed, without erosive slippage between them.

The shreds 67 are stripped from the slots or grooves 66 by the spring fingers of a comb-shaped stripper 70, the tips of these fingers projecting into the slots or grooves in the manner shown in FIG. 3. The stripper 70 is mounted on base plate 61 and the pressure of its fingers on the bottoms of the corresponding slots or grooves 66 may be adjusted by screw 71. A spring scraper 72 mounted on base plate 61 engages the surface of smooth roller 59 to clean off any surplus material which may have adhered thereto. This surplus material may be discharged to a receptacle, not shown, for return to storage bin 24, for example.

The formed shreds 67 of reclaimed tobacco fines are deposited by the forming rollers 58, 59 on a conveyor belt 73 preferably made of stainless steel, and driven at the same surface speed as the rollers 58, 59 by suitable means, not shown. The shreds are passed by belt 73 through a drying chamber 74 where it is heated from below by suitable heating means, such as gas burners, and from above by radiant heaters or combinations thereof. In the drying chamber 74, the shreds are dried to about 20% moisture content.

The shreds are discharged by belt 73 to the chute 75 of a vibrating or shaking type separator 76 where any agglomerated or Siamese shreds are removed and returned by pneumatic conveyor system 77, 78, 79 to the input pipe 34 of the dispersion machine for reprocessing. Those shreds which are not oversize are passed by screen 76 to vibrating screen 80 which passes the fines to suction pipe 81 for return to raw material storage bin 24.

The proper sized shreds 67 of tobacco fines reclaimed according to this invention are discharged from separator screen 80 to chute 82 which deposits them on driven conveyor 83 for blending with cut leaf tobacco on conveyor 84 receiving the same from rotary kiln drier 85. The proportion of reclaimed shreds from belt 83 is 2 to by weight, 98 to 90% by weight, of cut tobacco on belt 84 which accordingly deposits the same in this proportion into a rotary kiln type of cooler 86- which cools and blends the reclaimed tobacco shreds and cut tobacco leaf for use in manufacture of cigarettes or other tobacco products in cigarette machine 88 to which it is carried from cooler 86 by conveyor 87, which may, instead, carry the blend to storage for use when required.

The process and apparatus of this invention will be readily understood from the foregoing description of the schematic flow diagram of FIG. 1 and the shred making machine illustrated by FIGS. 2, 3 and 4, and the process may be further exemplified by the following tabulation of ingredients and proportions of a typical composition of the reclaimed tobacco material supplied to the shredforming rolls 58 and 59:

Tobacco Powder and Cellulose Fibers Percent Lbs.

Cigarette Dust 50 0 100 Slivers 38.0 76 #8 Bright (Particles passing a No. 8 screen 5.0 10 #8 Burley (Particles iassing a No. 8 screen) 2.0 4 Cellulose Fibers (S01 a-Floc BW40) 5.0 10

Binder Percent Percent Material Lbs. Total Added to Binder Tobacco Sugar-Humectant Solution Percent Percent Material Lbs. Total Added to Liquid Tobacco Nulomoline 9. 93 6. 45 4. 97 Glycerine 5. 93 3. 2. 97 Propylene Glycol 1.00 0.65 0.50 Methyl p-hydroxybenzoate 0.02 0.01 0.01 Water 137. 12 89. 04 68. 56

Total 154.00 100.00 77. 01

It will be understood that the formulations, methods and apparatus herein described are illustrative of the invention, which is not to be limited thereby, except within the scope of the appended claims.

We claim:

1. A method of reclaiming tobacco resulting as. a waste byproduct of the manufacture of smoking tobacco products, which comprises grinding the tobacco to about 60 to 100 mesh particle ize, separating therefrom any tobacco powder formed by grinding said tobacco, mixing the ground tobacco with a binder in an amount sufficient to moisten said tobacco but insufiicient to render said tobacco wet and capable of being balled by hand, and passing the resulting mixture between a smooth surface roller and a grooved roller in rolling contact to compress the resulting mixture into filamentary shreds having the approximate dimensions of cut leaf tobacco for admixture with cut natural leaf tobacco.

2. A method of reclaiming tobacco resulting as a waste by-product of the manufacture of smoking tobacco products, which comprises grinding the tobacco to about 60 to 100 mesh particle size, separating therefrom any to bacco powder formed by grinding said tobacco, increasing the natural moisture content of the tobacco to between about 30 and about 40 percent by weight, and passing the moistened ground tobacco between a smooth surface roller and a grooved roller in rolling contact to compress the moistened ground tobacco into filamentary shreds having approximately the dimensions of cut leaf tobacco for admixture with cut natural leaf tobacco.

3. A method of reclaiming tobacco resulting as a waste by-product of the manufacture of smoking tobacco products, which comprises grinding the tobacco to about 60 to 100 mesh particle size, separating therefrom any tobacco powder formed by grinding said tobacco, impregnating the ground tobacco with an aqueous binder solution in an amount sufficient to moisten the tobacco but insuflicient to render said tobacco wet and capable of being balled in the hand, and passing the impregnated tobacco between a smooth surface roller and a grooved roller in rolling contact to compress the impregnated tobacco into filamentary shreds for admixture with cut natural leaf tobacco.

4. A method of reclaiming tobacco resulting as a waste by-product of the manufacture of smoking tobacco products, which comprises grinding the tobacco to about 60 to 100 mesh particle size, separating therefrom any tobacco powder formed by grinding said tobacco, impregnating the ground tobacco with an aqueou humectant solution in an amount sufficient to moisten the tobacco but insufficient to render said tobacco Wet and capable of being balled in the hand, and passing the impregnated tobacco between a smooth surface roller and a grooved roller in rolling contact to compress the impregnated tobacco into filamentary shreds for admixture with cut natural leaf tobacco.

References Cited in the file of this patent UNITED STATES PATENTS Stayman Jan. 15, 1867 Kimball June 30, 1874 Kimball Apr. 5, 1881 Evers Oct. 25, 1910 Olson Dec. 9, 1924 Grunauer Feb. 16, 1932 Dahlstrom et al Mar. 14, 1939 Deich May 16, 1939 Wells et al. Jan. 6, 1948 Jurgensen et al. May 3, 1955 Bandel Nov. 6, 1956 Frankenburg et al Apr. 15, 1958 Samfield et a1. Aug. 5, 1958 FOREIGN PATENTS Germany Sept. 18, 1925

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