US 3136321 A
Description (OCR text may contain errors)
June 9, 1964 Filed Sept. 14, 1961 Fig. 2
MOISTEN PROCESS TOBACCO TREATM ENT MATERIAL MIXING DRYING MILLING APPLYING A. C. DAVIS METHOD FOR TREATING TOBACCO FINELY DIVI PARTICLES TREATMENT MATERIAL MIXING AND DRYING 7 Sheets-Sheet 1 Fig.
FIN ELY DIVIDING TREATMENT MATERIAL r SEPARATING DED REMILLING AND/OR REGRINDING PNEUMATICALLY O PROCESSED TOBACCO S TORAGE OR MAN UFACTURING 'REJECTED PARTICLES MOISTEN PROCESS TOBACCO APPLYING PN EUMQ'DI'ICALLY PROCESSED TOBACCO ST%RRAGE MANUFACTURING IN VENTOR.
Alfred Char/es Dav/s W KMWM Attorneys June 9, 1964 c, DAVIS 3,136,321
METHOD FOR TREATING TOBACCO Filed Sept. 14, 1961 7 Sheets-Sheet 2 INVENTORS Alfred Chqn'es Davis wit/MM, MI M June 9, 1964 A. c. DAVIS METHOD FOR TREATING TOBACCO 7 Sheets-Sheet 5 Filed Sept. 14, 1961 /N VE NT 0/2 Alfred Char/es Dav/I9 Attorneys June 9, 1964 Filed Sept. 14, 1961 A. C. DAVIS METHOD FOR TREATING TOBACCO 7 Sheets-Sheet 4 A TTORNE Y5 June 9, 1964 A. c. DAVIS 3,136,321
METHOD FOR TREATING TOBACCO Filed Sept. 14, 1961 7 Sheets-Sheet 5 INVENTOR Alfred Char/es Davis Attorneys June 9, 1964 A. c. DAVIS METHOD FOR TREATING TOBACCO '7 Sheets-Sheet 6 Filed Sept. 14, 1961 m Qh Attorneys June 9, 1964 A. c. DAVIS 3,136,321
METHOD FOR TREATING TOBACCO Filed Sept. 14, 1961 7 Sheets-Sheet 7 Fig. 10
INVENTOR- Alfred Char/es Dav/s by mm, W WM/Q Attorneys United States Patent 3,136,321 METHQD FGR TREATING TGEACCO Alfred Charles Davis, Westbury-on-Trym, Bristol, England, assignor to The Imperial Tobacco Company (of Great Britain and Ireland) Limited, Bristol, England, a British company Filed Sept. 14, 1961, Ser. No. 138,554 (Iiairns priority, applieation'Great Britain Aug, 18, 1955 7 Claims. (Ci. ISL-44b) This invention relates to a method of treating process tobacco in the form of leaves or leaf pieces and puffed tobacco formed of leaves and leaf pieces, which method consists in adding to the process tobacco finely divided treatment material so as to form a discontinuous coating on the. process tobacco without the necessity of specially treating the process tobacco in order to cause the treatment material to adhere thereto, other than perhaps using a tobacco base adhesive material to enhance the adherence of the treatment material to the process tobacco.
This application is a continuation-in-part of abandoned applications, Serial No. 603,474, filed August 13, 1956, Serial No. 702,391, filed December 12, 1957, Serial'No. 853,224, filed November 16, 1959, and Serial No. 103,504, filed April 17, 1961.
The object of the present invention is to provide improved methods and apparatus for treating process tobacco, as hereinafter defined, with finely divided treatment material, as hereinafter defined, in order to improve the process tobacco.
It is a further object of the present invention to provide a method of applying finely divided dry treatment material to water moistened process tobacco to cause the treatment material to adhere to the process tobacco due to the inherent gumminess of the moistened process tobacco to form a discontinuous coating of the finely divided treatment material on said process tobacco.
It is a still further object of the present invention to provide a method of enhancing the adherence of the finely divided treatment material to the process tobacco by mixing with the process tobacco and/or the finely divided treatment material a tobacco base adhesive.
Another object of the invention is to improve the flavor or smoking characteristics of process tobacco by the addition thereto of a flavoring material in the form of dry finely divided treatment material.
The expression process tobacco refers to the tobacco which is to be processed from raw material into a finished tobacco article, and includes natural tobacco, as opposed to reconstituted tobacco, in the form of leaves and leaf pieces and puffed tobacco formed from leaves and leaf pieces. Puiled tobacco is normal tobacco that has been subjected to an operation that expands the cell walls substantially beyond their elastic limit, and one suitable method of puffing tobacco leaf and/ or stem comprises supplying steam thereto in a container in the substantial absence of air, increasing the steam pressure upon and correspondingly the temperature of the tobacco and then suddenly reducing the pressure by connecting the container with a chamber maintained at a pressure considerably below atmospheric.
Such puffed tobacco, as hereinbefore explained may be used as process tobacco, and it is prepared and used in the same manner as normal tobacco.
The expression treatment material refers to the substances which are applied to the process tobacco by the method according to the invention. Such treatment material can be tobacco material, which includes scrap, waste or blending tobacco, including scrap formed during the making of puffed tobacco, and whole or parts of leaves from either natural or pufi'ed tobacco. In the normal preparation of tobacco to render it suitable for smoking,
either as pipe tobacco or as a filler in cigarettes or cigars, or for use as snuff, a certain amount of scrap tobacco, comprising for example, leaf lamina or stem, is produced.
For example, one operation that is frequently employed 1 are separated and removed, since they are unsuitable for smoking because of their high cellulose content. These unsuitable thick portions of stem are usually not absolute- 1y clean, that is to say all pieces of lamina are not necessarily removed from them, and such pieces constitute valuable leaf, not only from a monetary value point of view, but also because they may be of good quality tobacco.
A subsequent operation can be performed on the thick portions of stem to remove the pieces of lamina, but even then the pieces are considered as scrap tobacco because of their small size, since, when they subsequently pass with the larger pieces of lamina to a machine for cutting, these small pieces are further reduced in size and thus become very small bits that may, for instance, fall out of the ends of cigarettes when the cigarettes are loosely in a packet.
Medium thickness portions of stem, i.e. stems further from the butts, would be not so unsuitable for smoking as the thick portions, were it not for the fact that they form hard lumps, known as spills, in the tobacco and may pierce the paper of a cigarette, thus rendering it unsuitable for smoking. Thus medium stems also provide a source of scrap tobacco. 1
In manufacturing operations shredded tobacco is sometimes rendered unsuitable for use. For example, if a defeet occurs in a cigarette machine a considerable amount of cigarette rod may be formed before the machine is stopped and such rod must be discarded as the shredded tobacco is then unsuitable for reuse in that manufacturing operation. Tobacco which has been discarded during a manufacturing operation, either in shredded or other form, is herein referred to as waste tobacco.
Thus in the preparation of tobacco to render it suitable for smoking and in manufacturing operations to provide tobacco articles, there are many sources of scrap and Waste tobacco, that is to say tobacco which is normally unsuitable for use, although it is usually of good quality. It will be appreciated that this material may be leaf lamina, stems, or may be cut or shredded tobacco.
Due to the high cost of tobacco it is most undesirable to discard this scrap or waste and there is, a further point that if high quality scrap or waste tobacco could be rendered suitable for smoking it could then be mixed with inferior quality tobacco to improve the smoking properties of the latter.
Another source of tobacco which may be used in treating process tobacco according to this invention is what may be termed blending tobacco, that is, good quality tobacco chosen for its blending or flavoring properties and adapted to improve the smoking properties of process tobacco of inferior quality.
The treatment material can also be a material other than a tobacco material, such as a flavoring material which has been suitably prepared and then finely divided and applied to the process tobacco in the same manner as the tobacco treatment material.
The invention will now be described in more detail using the above definitions and with reference to the accompanying drawings, in which:
FIG. 1 is a block diagram illustrating the steps of the method according to the present invention;
FIG. 2 is a block diagram of a slightly different form of method than that shown in FIG. 1
Patented June 9, 1964 paratus for carrying out the method illustrated in FIG. 2;
FIG. 8 is a schematic view of a slightly different apparatus for carrying out the method illustrated in FIG. 2; FIG. 9 is a schematic representation of an apparatus for carrying out the method according to the invention in which a tobacco base adhesive is mixed with the treatment material;
FIG. 10 is a schematic representation of an apparatus similar to that shown in FIG. 9; and
FIG. 11 is a schematic representation of an apparatus for carrying out the method according to the invention when the treatment material is a flavoring substance.
As shown in FIG. 1, the method according to the invention consists essentially of preparing the treatment material to be added to the process tobacco by mixing and drying the particles of scrap, waste, and/or blending tobacco or the like and then finely dividing it by milling and/ or grinding it. In the form of the method illustrated in FIG. 1, the thus finely divided treatment material is separated into two parts, one part having particles up to 75 microns in size and the other part having particles over 75 microns in size. The smaller particles are hereinafter referred to as fines, and the larger particles are referred to as tailings. The tailings are remilled and/ or reground, and again separated, further fines being obtained, these fines being added to the fines obtained by the original reducing step. The remaining tailings are then rejected.
The process tobacco is moistened with water to regulate the water content thereof from about 17% to about 35%, the lower limit being that at which cigarette tobacco is usually handled during the manufacturing process. In applying the present invention to pipe smoking tobacco the finely divided treatment material is produced in the same way as above described but the process tobacco to be treated is given a moisture content of about 35%. This is so because, during manufacture, pipe tobacco is usually brought to a higher moisture content than cigarette tobacco and it has been found convenient to treat it at a stage where the moisture content is highest. It may, however, be treated at any other suitable stage of manufacture.
In the case of cigars the filler tobacco, the binder leaves and the wrapper leaves, which all constitute process tobacco, may all be treated, the filler and binder preferably when at a moisture content of about 25% and the wrapper preferably after formation i.e. at a moisture contentof about 20%.
While approximate moisture contents have been referred to both as regards the treatment material and the process tobacco to be treated, it is to be understood that these are not critical, and have only been stated because in experiments so far carried out the process tobacco has been treated at a stage in manufacture that was found convenient, and the moisture content at these different stages have been quoted. In this connection it should be noted that tobacco in the form of leaves and leaf pieces and puffed tobacco in the form which has a moisture content greater than about is gummy and that this gumdivided droplet form, in which form it is picked up rather rapidly and easily by the tobacco. In this connection it should be noted that tobacco has a great afiinity for moisture and thus it can be said that it is probably never completely dry, in fact after a short time its moisture content reaches equilibrium with, or substantial equilibrium with, that of the surrounding atmosphere. Similarly when the word drying" is used it is not intended to infer that the tobacco is completely dry but that some moisture has been removed.
The fines, consisting of particles up to 75 microns in size, are then applied to the thus moistened process tobacco. It is preferred to do this by blowing the particles on in air. The fines adhere to the process tobacco as a discontinuous coating, that is to say, a leaf of process tobacco examined under a microscope after treatment will be found to be almost entirely covered with the particles, but such particles adhere as a discontinuous coating in that the bare leaf can be seen between at least some particles. Such a coating is to be distinguished from a coating of finely divided colloidal sized tobacco particles applied as a solution, sol or slurry to provide a continuous film on the tobacco to be treated. It should be noted that process tobacco under treatment may be in a tangled condition and so certain portions of it may not be exposed to the tobacco particle laden air in the treating drum, and the word discontinuous does not refer to these untreated portions but, as hereinbefore explained, to the fact that the various particles do not form a continuous film 0n portions exposed to the said air.
The coating consists only of the particles of treatment tobacco. The adherence of the finely divided particles of treatment material is due to the inherent characteristics of the moistened process tobacco, which is, to a large extent due to the presence in tobacco leaves, both lamina and stems, of sticky matter, e.g. sugars, pectins, nicotine, resins and Waxes. Such matter is hereinafter referred to as tobacco base adhesives.
It has been found that if dry tobacco is moistened, the inherent stickiness is apparently increased. Further, if tobacco is cut into shreds the apparent inherent stickiness is increased because the tobacco base adhesives normally below the surface are exposed where severance takes place. By increasing the inherent stickiness of the surface or exposing such adhesives normally below the surface, it is possible to bring about a firm adherence of the applied tobacco powder and also a greater quantity of powder per unit area will adhere to the tobacco than will so do to dry or uncut tobacco.
Example I As an example of a typical factory operation, 1000 pounds of process tobacco, which in this instance Was normal leaf tobacco, and which had a moisture content of 19.6% had added thereto 64 pounds of treatment tobacco with a moisture content of 7.65%, the treatment tobacco being reduced so that 9293% had a particle size of 75 microns or less. After the process tobacco was treated, and then placed in cigarettes in a c0nventional manner, approximately 75% of the treatment tobacco was retained on the process tobacco, the treatment tobacco thereby constituting about 4.7% of the total weight of the cigarette tobacco.
In the steps of preparing and finely dividing the treatment material, it is preferred to dry the treatment material either prior to or during the step of finely dividing it to a moisture content of from 5-6%. The step of finely dividing the treatment material can be carried out by first grinding the treatment material and then mulling the ground treatment material. This will reduce a relatively large portion of the treatment material to a size of less than 75 microns.
Referring to FIGS. 3, 4, 4a and 5, the scrap and/or waste tobacco or the like which constitute the treatment material is delivered to a feed conveyor 1 from a scale 2 so that the weight of treatment material fed may be c0n- -wall 221) of the drum within which they rotate.
. trolled. The treatment material is delivered to an inclined rotating drying cylinder 3, heated by gas jets 4, and
.the drying cylinder 3 has tines 5 to mix the scrap and waste and other materials together, and feed the material through the cylinder 3, while, at the same time, the material is dried to a water content of about 5% to 6%.
A conveyor 6 then carries the mixed and dried treatment material to a milling device 7 that is secured to one side of a conical hood 3 surmounting a mulling mechanism 9. Betweenthe milling device '7 and the hood 8 is interposed a rotary valve 10.
The milling device 7 is of the type comprising a cylindrical chamber having a plurality of inwardly directed peripheral blades coating with knives on a rotating vaned drum whereby, as the treatment material passes through, it is cut or chopped into small pieces of say /s" to 1 across. The valve 10 rotates slowly to permit the said pieces to fall through an orifice 11 into the interior of the muller 9. The valve 10 is interposed to prevent escape of air during the passage of chopped small pieces of treatment material from the milling device 7 into the muller 9.
Preferably the small pieces of treatment material pass through a screen into the rotary valve 10 so as to prevent pieces above a predetermined size passing into the muller 9.
The muller 9 is of the type comprising a rotating cross head 9A having eccentrically mounted thereon a pair of freely pivoted grinding rollers 9B which, under the effect of'centrifugal action, rotate in contact with the wall of the muller casing so as to grind material fed therebetween. The crosshead 9A also carries a pair of flow type deflectors 9C adapted to gather the material and feed it continuously between the casing and roller. The grinding rollers 93 are of appreciable weight and the crosshead 9A revolves at a-high speed with the result that chopped small pieces of treatment material fed to the muller 9 are ground to particles varying in size from about 1 to 500 microns (30 British Standard Mesh);
A centrifugal fan 12 is adapted to create a current of air flowing steadily around the circuit provided by the trunking 13, 13A.
The center of the conical hood 8 is provided with an elbow piece which projects into the trunking with its opening directed downstream of the air flow. The presence of the elbow piece 14 reduces the cross sectional area of the trunking 13, thus forming a venturi from the muller.
By this arrangement, the current of air flowing around the trunking 13, 13A and passing over the venturi 14, acts to draw powdered treatment material from the muller 9 when the particles in said material have been ground to a size suificiently small that they become airborne, that is, at the most 500 microns. An air inlet 15 controls the air flow into and within the muller and prevents any tendency for a vacuum to be created there, but the inlet 15 is so-small as not to interfere with the current of air in the trunking 13, 13A.
The finely powdered treatment tobacco particles (1- 500 microns) then pass along the trunk 13 into a cyclone chamber 16. This, as can be seen from FIG. 5, comprises a number of separating tubes 17 having peripheral slots, the arrangement being such that the air current flowing past the slots acts to swirl the powdered material into the tubes, down which it falls through a rotary valve 18 on to a conveyor 19. It will be seen that the conveyor 19 is enclosed by a shield 20, and this shield continues as far as an entry hopper 21 to a centrifugal separator 22. p Y
The air separator 22 is conveniently of the type which comprises a number of discs 22A rotating on a hollow central spindle 22B, one below the other, within a drum 22C, said discs being smaller in diameter than an interior Peripheral vanes 22E extend inwardly and downwardly from said interior wall 22D, so as to collect powder thrown from one disc and direct it on to the disc immediately below. A fan 22F arranged at the top of the apparatus creates a current of air which flows upwardly past the edges of the discs 22A and vanes 22E, and then downwardly outside the interior wall 22D, through a gap into the interior again. A hopper 226 is located below the lowermost disc and vane to receive the tailings.
The hollow central spindle 22B constitutes an entry tube positioned centrally above the discs 22A and this leads powdered tobacco from the hopper 21 onto the topmost disc. The discs 22A rotate at high speed and throw the powder centrifugally onto the current of air. Light particles are raised in the air current and pass down outside the interior wall to a delivery orifice 23.
Particles too heavy to be raised by the air current are guided by a vane to the disc below where the same operation takes place. This operation is repeated according to the number of discs (e.g. six) and finally the tailings fall out of the apparatus throughthe orifice 24. By means of conveyor 25, these tailings are either returned to the muller 9 in some convenient manner, or are rejected. Rotary valves 26, 27 control the openings 23, 24 in order to avoid any interference with the air current.
A separator as above described divides the powder into two grades. The ascending fines, which constitute finely divided treatment material, vary in size from about 1 to microns, and the tailings are above 75 microns.
Thus particles from about l-75 micron size pass through the delivery orifice 23 and the valve 26 to an enclosed conveyor 28 that delivers them to a hopper 29 above a powder dispenser 32, while tailings (above 75 microns) pass to the conveyor 25.
The hopper 29 then delivers the fines of the treatment material through another rotary valve 31 to the powder dispenser 32. This is of known type and includes a compressed air supply pipe 33 and powder delivery pipe 34 terminating in a nozzle 35.
The nozzle 35 delivers material to a substantially closed rotating cylinder 36 having internal tines 37 and being set on a slant, the arrangement being such that said cylinder contains a mist of finely powdered treatment material. Process tobacco, which preferably has already been moistened with water to a moisture content of 17-35%, is continuously delivered by a conveyor 38 to the cylinder 36 and, while it is being fed therethrough by the tines 37, the powder blower nozzle 35 creates in the drum 36 an atmosphere laden with the fines, the dry particles of which adhere to the moist process tobacco.
Preferably a weighing mechanism is included inv the conveyor 38, but this is not shown in the drawing. By weighing the process tobacco delivered by the conveyor 38 in conjunction with the weight of the treatment material shown on the scale 2, the rate of supply of material to the process tobacco may be controlled.
A conveyor 39 receives process tobacco treated with treatment material, and this tobacco is then passed for further processing in the usual way. An extractor 41 removes surplus powder laden air.
' As shown in FIG. 2, the method according to the invention is substantially the same as that shown in FIG. 1, except the treatment material is finely divided in a single step which consists of subjecting the fragments of treatment material to the action of high velocity jets of a compressible fiuid. The mehod consists essentially of preparing the treatment material to be added to the process tobacco by mixing and drying the particles of scrap, waste and/ or blending tobacco or the like, and then subjecting it to the action of high velocity jets of a compressible fluid such as air or some other gas. This action will reduce the particles to powder having particles up to 75 microns in size, and these particles are applied to process tobacco moistened in the same manner as described in connection with the method as illustrated in FIG. 1.
Referring to FIGS. 6 and 6a, the treatment material is delivered by a weighing device 41a onto a conveyor 41 by which the treatment material is delivered to a rotatable drum 42 in which it is thoroughly mixed together and simultaneously dried to a moisture content of about A conveyor 43 passes the mixed and dried treatment material into a mill 44. This mill 44 is of conventional design and includes a rotating cutter that cooperates with interior peripheral knives to chop the treatment material into small fragments. The fragments pass continuously from the bottom of the mill 44 into a hopper 45 that leads to a second mill 46.
The mill 46 comprises a circular chamber 47 having a plurality of somewhat tangentially directed orifices 48, said orifices communicating through ports 49 with a common annular tube 56. The common annular tube is connected at 51 to a source of compressed air. To the upper wall of said chamber 47 and at the center thereof is secured a flange 52 on an exit pipe 53 for air, said pipe leading to a filtering sock 54, while at the center of the lower wall of the chamber 47 is secured an exit tube 55 for the powdered treatment material. This exit tube 55 directs powder through a valve 56 towards a conveyor 57. A delivery passageway 58 is secured to the upper wall 59 of the chamber 47 through which fragments of treatment material may be delivered to the interior of the chamber 47. The delivery passage 58 may conveniently include a screw conveyor for delivering fragments into the chamber, or alternatively the fragments may be delivered by venturi action.
The operation of the above described mill 46 is as follows:
The treatment material is delivered through the passage 58 into the chamber 47 where it is subjected to the action of the air jets issuing through the tangentially disposed orifices 49. This effects attrition between the fragments and they are quickly reduced in size to particles of powder on the order of 1 to 75 microns. The action of the air jets also causes a vortex within the chamber that acts to carry the powder towards the center of the chamber whence it passes through the exit tube 55 and the valve 56 on to the conveyor 57. The majority of the exhausted air passes through the tube 53 and any dust that is entrained therein is collected in the sock 54. A certain amount of air also passes through the tube 55 and carries the powdered treatment material with it.
It has been mentioned above that the treatment material is quickly reduced to particles of powder on the order of l to 75 microns, but it is to be understood that the particle size is dependent on the exact operation of the mill. Thus the size to which the material is reduced is dependent on the speed of delivery of particles of treatment material through the passage 58 and the force of air through the orifices 48, and these are so chosen as to reduce the fragments of treatment material to a particle size of 1 to 75 microns at the speed desired to maintain the whole apparatus in continuous operation at a suitable speed to suit the manufacturing operation.
A rotatable drum 60 is provided, set on an inclination, and having internal tines 61 adapted, when the drum is in rotation, to mix powdered treatment material fed by the conveyor 57 and process tobacco together and feed the treated process tobacco towards a delivery conveyor 62. A feed hopper 63 is provided for feeding the process tobacco to the drum 60.
A funnel 64 provides a passage, leading through a fan 65 to a filter sock 66, in which surplus powder may be collected. The above apparatus works in the following manner: Treatment material is fed from the conveyor 41 into the mixing and drying chamber 42 and by the conveyor 43 to the first mill 44 where it is chopped into small fragments. These fragments are then ground in the second mill 46 to particles of powder on the order of 1 to 75 microns and said powder is then fed from a weighing conveyor 6311, into the rotating cylinder 60. Here the process tobacco and powdered treatment material are thoroughly mixed and delivered to the conveyor 62 which carries the treated tobacco away for further manufacturing operations. It will be appreciated that by providing the conveyor 41 and the conveyor 63a as weighing conveyors, the proportion of powdered treatment material being applied to the process tobacco can readily be controlled.
The embodiment illustrated in FIG. 7 corresponds substantially with that above described with regard to FIGS. 6 and 6a, except that the second mill 46 feeds the powdered treatment material to a powder blower 67, from which the powder is forcibly applied to the process tobacco through a pipe line 28. Thus the parts in FIG. 7 have been given the same numbering as FIG. 6a and the operation is the same, except that instead of applying the treatment material to the process tobacco by mixing it therewith in the cylinder 60, said treatment material is forcibly blown into said chamber by the powder blower 67 so that the process tobacco, in passing through the chamber, passes through an atmosphere containing powdered treatment material.
FIG. 8 shows the application of treatment material powdered in accordance with the invention to process tobacco and subsequent manufacturing operations. Member '70 is a vibratory conveyor for feeding process tobacco through a hopper 71 into a timed rotating cylinder 72. "While the process tobacco is on the conveyor 70 and being agitated thereby, powdered treatment material is delivered from a hopper 7 3 through the passage 74 on to the process tobacco as it passes beneath it.
The treated tobacco passes from the cylinder 72 into a hopper 75 that is common to a plurality of tobacco cutting machines 76, 77 and 78. The treated tobacco in the hopper 75 is delivered beneath a pinned refuser roller 79 onto a conveyor 80 from which it falls onto a conveyor 81 moving at right angles to conveyor 80. The treated process tobacco falls off the end of the conveyor 81 onto the vaned drum 82, which normally rotates in a counterclockwise direction, and by which the treated process tobacco is fed into a funnel 83 leading to the cutting machine 76. A suitable mechanism is provided that when hte hopper of the machine 76 is full, the mechanism acts to reverse the rotation of the vaned drum 82, so that tobacco falling onto said drum is delivered onto a conveyor 84. Machine 77 has a vaned drum 85 which in a similar way, passes the tobacco through a funnel 86 leading to the machine 77. When both machines 76 and 77 are filled, the machine 78 is filled through the funnel 87 in a similar manner, and so on.
FIG. 8 is included mainly to indicate various positions at which powdered treatment material may conveniently be applied to process tobacco and be agitated therewith to provide a discontinuous coating of the powdered treatment material on the tobacco and also to indicate means by which the treated process tobacco may be compressed so as to bind the treatment material into intimate contact therewith. Furthermore, it shows where the treated process tobacco is cut to release sugars or the like to the surface to assist in the adherence of the powdered treatment material.
Thus treatment material may, as hereinbefore described, be added to and dispersed throughout the process tobacco while the latter is being agitated by the vibratory conveyor 7 0, it may be added directly into the cylinder 72 and be dispersed throughout the process tobacco by agitation due to the rotation of said cylinder, it may be added to process tobacco in the hopper 75 and be dispersed throughout said tobacco due to agitation therein by rotation of the pinned roller 79, or it may be added 'to process tobacco on the conveyor 81 and be dispersed throughout the tobacco due to agitation by means of the vaned drum 82.
Machines 76, 77 and 78 are tobacco cutting machines of which parts 88, 89 and 90 are rotary knives and it is to be understood that these machines operate on the general principle of compressing the tobacco in the hoppers 9 a 91, 92 and 93 to form a hard cheese and cutting the cheese with knives 88, 89 and 90. Thus the treatment material in said hoppers is bound into intimate contact with the tobacco therein due to compression, while the action of the rotary knives 88, 89 and 90 on the treated tobacco acts to release sugars or the like to the surface and so assist in the adherence of the treatment material to the tobacco.
A Vibratory conveyor 94 delivers tobacco from the cutting machines for further manufacturing, e.g. for bulking and then passing to cigarette making machines. Bulk ing here refers to a process which is customarily carried out at several stages of tobacco manufacture with the object of evening out moisture control variations and consists in storing the tobacco in suitable containers, for example, bins, for a period of time.
it is often desirable to augment the adhesion between the process tobacco and the finely divided treatmentmaterial. This is done by utilizing tobacco base adhesives obtained from waste tobacco which would otherwise have to be discarded. The use of waste tobacco is the most economical way of providing tobacco base adhesive to increase adherence between tobacco powder and tobacco to be treated. This is because it is recovered from tobacco which, because it is unsuitable for normal manufacture, would otherwise be useless, but it is to be understood that Where the expression waste tobacco is used it is to be deemed to mean tobacco, either stem or leaf, other than the tobacco to be treated.
In the manufacture of tobacco articles, that is to say pipe tobacco, cigarettes and cigars, a small proportion of each original tobacco leaf is normally discarded for some reason or other. For example, a considerable amount of the midrib, particularly at the butt end, is too coarse or Woody to be used in the manufacture of such an article. i
The veins which branch outwardly from the midribs are also somewhat woody, particularly those nearer the butt end, and the portions of veins at the branching points. These veins are used in the manufacture of tobacco articles as are also the thinner portion of the midribs, but in the manufacture of cigarettes there is provision for collecting hard pieces of midribs and veins that constitute what is known as spills if allowed to remain in a completed cigarette. Further, the collected spills frequently have entangled therewith strands of tobacco which being difiicult to separate, are normally discarded with the spills.
Other tobacco manufacturing processes provide a source of waste in the form of original leaves that are normally discarded, and also tobacco-from faulty cigarettes which cannot be reused in the manufacturing process.
All such woody portions of midn'bs or veins, spills or faulty tobacco contain tobacco base adhesives and thus provide waste tobacco as above referred to. Sometimes however, it is found advantageous to recover such adhesives, or at any rate a proportion of such adhesives, from one batch of tobacco and apply it to another batch in order to vary the stickiness of the two batches or'to vary the flavor thereof.
In order to obtain dry tobacco base adhesive, 350 lbs. of waste tobacco it is first steeped in 10,000 lbs. of cold water for a period of from two to three hours until the soluble tobacco base adhesives in the waste tobacco are thoroughly in solution, and thereafter the solid matter tobacco results 'from the application of tobacco base adhesives but, as will be evident to one skilled in the art, the color may be modified, e.g. by employing a methanol solvent method at a suitable stage in the process. Similarly, the nicotine content may be modified, e.g. by employing alcohol as a solvent to effect a reduction, or nicotine in solution with alcohol to effect an increase.
A suitable alternative source of liquid adhesive is the 'water issuing from a stem crushing machine, in which stem. is crushed between rotating rollers while being kept thoroughly wet during the operation and adhesives squeezed out of the stem are dissolved in the water.
The adhesivemay be used either by spraying it in a water solution onto the process tobacco to be treated, or by mixing it in dry powdered form with the finely divided treatment material to be applied to the process tobacco or with the process tobacco to which the finely divided treatment material is to be added.- If the adhesives are required for applying to tobacco in a liquid state then the solid mass can be roughly ground and broken down to a coarse powder and then dissolved in Example II 1,000 lbs. of process tobacco, which in this instance was normal leaf tobacco at a moisture content of 14.5% had sprayed thereon 131 lbs. of a tobacco base solution in water having an adhesive concentration by weight of 50%, further diluted with an additional 25 lbs. of wa- 64 lbs. of treatment tobacco at a moisture content of 3.9% was added thereto, the treatment tobacco being reduced so that 92-93% had a particle size of 75 microns or less.
After the process tobacco had been treated and subsequen'tly processed in a conventional manner to produce cigarettes, approximately of the treatment tobacco was retained on the process tobacco, the treatment tobacco thereby constituting about 5% of the total Weight of the tobacco (which included the increase due to the applied tobacco base adhesives) in the cigarettes.
. Example III 1,000 lbs, of process tobacco in leaf form at a moisture content of 20.6% had added to it 64 lbs. of treatment tobacco at 7.5% moisture content which had been reduced together with 61 lbs. of freeze dried tobacco base adhesives so that 92-93% of the mixture had a particle size of 75 microns or less.
After the process tobacco had been treated and subsequently processed in a conventional manner to produce cigarettes, approximately 80% of the treatment tobacco was retained on the process tobacco, the treatment tobacco thereby constituting about 5.4% of the total weight of the tobacco (which included the increase due to the added freeze dried tobacco base adhesives) in the cigarette.
Apparatus similar to that used for the application of the finely divided powder to the process tobacco without the use. of adhesives is used when it is desired to employ adhesives. I
Referring to FIGURE 9, the complete plant comprises a water supply 100, having a metering device 102, leading to a spray nozzle 103. The spray nozzle 103 directs a water spray to the interior of a cylinder 104, that rotates on wheels 105 and 106. Tobacco 107 to be treated, is fed at a controlled rate by a conveyor 108, so that it is also delivered to said cylinder 104, where, due to the rotation of the latter, it is thoroughly moistened by the water to a moisture content of about 19%.
The moistened tobacco 10?, issues from the cylinder 104 and isdeposited on an endless conveyor 110, which delivers it to a second cylinder 111 that rotates on wheels 1112 and 113. I p
The cylinder 111 comprises a container for receiving a mixture of adhesives and tobacco powder, and tobacco to be treated and for dispersing the mixture throughout the tobacco, as is hereinafter more fully described.
Above the cylinder 111 there is mounted suitable apparatus for delivering a mixture of powdered tobacco and powdered adhesives to a chute 114 leading to said cylinder 111. This apparatus comprises a weighing feed conveyor 115 for tobacco to be powdered (116 being a dial that indicates theweight of tobacco being delivered by weighing conveyor 115, so that the rate of feed of said tobacco may be controlled), a cylinder 117 for drying tobacco delivered by the conveyor 115 andfeeding it onto a conveyor 118. The conveyor 118 in turn delivers the .dried tobacco to a mill 119, that acts to chop the tobaccointo small pieces. From the mill 119 the small pieces of tobacco fall into a funnel 120, that leads through the injector 121 into a comminuting mechanism comprising a fluid energy mill 122. Tobacco base adhesives which have been extracted from waste tobacco and which have been dried and ground to a coarse powder are delivered by a conveyor 123, through a hopper '124 to a vibratory conveyor 125 that acts to deliver the coarse powder through a chute 126 into the same funnel 120, that leads through the injector 121 to the fluid energy mill. It is to be understood that the vibratory conveyor 125 is controlled so as to feed the coarse powder to the chute 126 at a given rate, and thus it will be air from the fluid energy mill 122 is conveyed through a pipe 129 to a sock 130 which collects such dust as may be present in the exhaust air.
The tobacco 107 to be treated, is weighed, either on the conveyor 108, or before it reaches said conveyor, and thus it will be appreciated that a measured quantity of tobacco to be treated and a mixture of tobacco powder and tobacco base adhesives is delivered to the cylinder 111. The rotation of the cylinder 111, which is preferably provided with internal tines or vanes, acts to mix the tobacco to be treated, and the mixture of tobacco powder and adhesives together thoroughly, and finally delivers it to conveyor 131, whence it passes for normal tobacco processing. For example, if it is to be made into cigarettes it passes to a tobacco cutting machine for shredding, while if it is to be made into pipe tobacco it may be pressed and subsequently cut.
Alternatively the dried powdered tobacco base adhesives can first be comminuted in any suitable mill, for example a ball mill, to a very fine condition, e.g. of the order of 1 to 75 microns, and then delivered by a conveyor similar to conveyor 123 through a hopper to a vibratory conveyor like conveyor125 which. delivers-a measured quantity of said powdered adhesives to the chute 114. In this case of course the conveyor 123 and associated parts as far as the chute 125, are dispensed with.
In a further alternative the tobacco base adhesives are applied in liquid form, thus the vibratory conveyor 125 and associated parts are not required. In this case, the liquid adhesives pass through a measuring device (not shown) to a tank 137 in water supply line 102 where they are mixed ,with the water entering from the pipe 191. I
The said adhesives and water mixture is then sprayed onto the tobacco to be treated, through the nozzle 103, while powdered tobacco only is added at the cylinder 111. The remainder of the operation works in a similar manner.
- 12 Referring to FIGURE, 10, like parts are given the same numbers as in FIGURE 1, and the general operation of the water supply 101, conveyor 108, cylinder 104, conveyor 110, cylinder 111 and conveyor 131 is the same a that described with reference to FIGURE 9.
The main modification in FIGURE 2 is that the powdered tobacco 138, and powdered tobacco base adhesives 139 are both comminuted in ball mills (not shown in the drawing), and it is to be understood that the said tobacco 138 and adhesives 139 are ground to a finenes of the order of 1 to 75 microns and are fed by conveyors 144 and 145. They are then delivered by conveyors 144 and 145 through hoppers 140 and 141 to vibratory conveyors 142 and 143 respectively, that act to deliver measured quantities of both powdered tobacco and powdered adhesives to the chute 114.
In an alternative, in'which the tobacco base adhesives are applied in a liquid condition, the conveyor 145 and its associated parts is replaced by a tank (not shown) leading through a measuring device (also not shown) to the tank 137, so that a measured quantity of liquid adhesives from tank may be mixed in the tank 37 with water from the pipe 101 and this mixture of adhesive and water is and augmented stickiness to cut tobacco, or to cigars.
Thus the powdered tobacco may be fed to the tobacco in the hopper of a'cigarette-making machine, for instance the chute 114 shown in FIGURE 9 may feed the mixture of tobacco powder and adhesives to said hopper, instead of to the drum 111, where it 'is thoroughly mixed with the cut tobacco due to agitation in the hopper. Cigars may be rolled in the mixture or alternatively the outer (binder) leaves may be treated in a similar manner to tobacco leaf.
According to another modification, not illustrated in the drawings, the powdered tobacco and tobacco base adhesives are delivered to leaf tobacco in the hopper of a tobacco cutting machine. For instance, instead of the chute 114 of FIGURE 1 feeding the mixture to a rotating cylinder, said chute feeds the mixture direct to a tobacco cutting machine hopper where it is thoroughly dispersed throughout the leaf tobacco, due to agitation in the hopper, the powder mixture is then compressed into intimate contact with the leaf, since tobacco in a cutting machine hopper is compressed to a hard cheese and is finally cut into shreds.
The preparation of the tobacco base adhesives, either liquid or dry is not illustrated in the drawings since any normal apparatus may be used that is suitable for dissolving soluble tobacco base adhesives from tobacco.
It is also often desired to add further treatment materials to process tobacco, particularly flavoring materials which improve the flavor and smoking characteristics of tobacco. The substances in question may be naturallyoccurring, synthetic or manufactured and are hereinafter referred to as additive materials, which term also includes a mixture of such substances.
Many examples of additives are referred to subsequently in this specification, but it is to be understood that the word additive materials as used herein does not include tobacco.
The tobacco to be treated may be for use in the manufacture of cigarettes, cigarillos, cigars or pipe tobacco, or it may be for chewing tobacco or snulf and it may be leaf lamina or shredded.
According to one known method of treating process tobacco with additive materials, the tobacco is first cut into shreds suitable for manufacturing into cigarettes, and pipe tobaccos such as shags and mixtures, and is conveyed to a suitable receptacle or container, or it may be laid on solvent, e.g. water. oralcohol, and'the solution is sprayed on the tobacco while it is agitated in the receptacle or container,-or issprayed over the tobacco laid on a floor or platform. Additives already in liquid form are sprayed on the tobacco direct orafter dilutionwith an appropriate solvent. i
In another, known method the additive materials, especially insoluble products such as cocoa, chocolate and spices, cinnamon, cloves etc., are ground to a relatively coarsepowder and sprinkled over the tobaccoto be treated, which may be leaves or leaf pieces or shredded tobacco. For the application of such additive materials the tobacco is laid on a floor or platform, or it may be agitated in a receptacle or container. This method ismore frequently applied in the manufacture of pipe tobaccos where the treated tobaccois subsequently highly compressed, thereby embedding the coarsely ground powdered additive materials in the tobacco so as to reduce the possibility of them becoming detached. Subsequently such compressedtobacco is usually cut into slices.
According to another known method, leaf tobacco is dipped in a solution or a suspension of the relatively lcoarsely ground. additive materials in water, any excess of solution being drained off or removed by means of a 'wringer, and the wet tobacco product subsequently dried before cutting.
The above described methods of treating tobacco with additive materials to alter the characteristics of tobacco are not entirely satisfactory since as they usually involve the use of separate processes, the normal procedures of manufacture are seriously interrupted While the treating operation is carried out, different classes of tobaccos call 7 for different techniques, and distribution of the additive materials throughout the tobacco is not as uniform as could be desired. Furthermore, in'respect of some additive material's, e.g.' balsam, tonka bean, vanilla, spices,
elaborate processes, equipment and storage facilities are usually required for preparing extracts of such products inthe appropriate solvents.
When applying insoluble additive materials to leaf or shredded tobacco as above described, some'proportion tends to settle out of the tobacco during subsequent processing and after packing in containers for storage particles of the powder and the tobacco assist adhesion.
The additive materials may be fed continuously for application to the tobacco tobe treated while said tobacco is also being continuously fed.
Alternatively a predetermined quantity of additive materials may be fed for batchwise application to the tobacco to be treated.
It has been found that the reduction of additive materials to a particle size of from l75 microns is sufficient to cause such particles to adhere firmly to the tobacco. In the continuous process the finely powdered additive materials may conveniently be applied to the tobacco to be treated, e.g. leaf or shredded tobacco, when said tobacco is beingconveyed through a rotating drum. It may be forcibly applied by means of a powder blower or dusting machine. Additionally, the treated tobacco may be compressed to assist adherence of the powder. This .also acts to bring out a stickiness in the tobacco that is not normally apparent.
Theadditive materials may be ground with tobacco to produce an intimate mixture of finely powdered to- In some circumstances, e.g. when it is desired to apply additive materials to. tobaccosof relatively. little stickiness, such. as Burley tobacco, 'or when it is desired to apply, a large quantity ofboth powdered tobacco and additive materials to tobacco, it may be desirable to increase the stickiness of the tobacco to be treated.
- This can be achieved by adding tobacco base adhesives asdescribed above.
To obtain the additive materials in dry powdered form,; it will be sufficient, where they are in the form of sugars, dried spices and other such dried flavoringmaterials, to first coarse grind them and then mull them until the particles are reduced to a particle size of 75 microns or less. Alternatively, it is also possible to subject such materials to attrition by means of a high velocity stream of. air, as described. above for the treatment of tobacco materials. I
,Where the additive materials are not only in a dry form, it will be necessary to prepare them in this form in. a manner similar to that in which the tobacco base sequently grinding theresulting dry product to the proper particle size.
Example IV 1,000 lbs, ofprocesstobacco in leaf form at a moisture content of 20.6% had added to it. 64 lbs. of a mixture of treatment tobacco and spices, which mixture had a moisture content of 7.5% and which had been reduced so that 92-93% of themixture had a particle size of 75 microns or less;
After the process tobacco had been treated and subsequently processed in a conventional manner to produce cigarettes, approximately of the treatment tobacco and spice mixture was retained on the process tobacco, the mixture thereby constituting about 5% of the total weight of the tobacco in thecigarette.
Because the manner in which the additive particles adhere .to the process tobacco is the same as the manner in which the. treatment tobacco particles adhere, the additive can be substituted for the treatment tobacco in Example .V I
1,000 lbs. of process tobacco in leaf form at a moisture content of 20.6% had added to it 32 lbs. of an additive of. spices which had a moisture content of 7.5% and .Which had been reduced so that 9295% of the additive had a particle size of 75 microns or less.
After the process tobacco had been treated and subsequently processed in a conventional manner to produce cigarettes, approximately 80% of the additive was retained on the process tobacco, the additive thereby constituting about 2.5% of the total weight of the tobacco in the cigarette.
'A form. of apparatus for adding additive materials in the form of finely divided treatment material'is illustrated in FIG. 11. I I
A vibratory conveyor 151 feeds additive materials 152 from a hopper 153 at a predetermined rate to a fluid energy mill 154. Simultaneously, chopped or shredded tobacco 155 is delivered by a weighing conveyor 156 through-a drying cylinder 157 to the fluid energy mill-154, and in said mill the tobacco and additive materials are intimately mixed and ground to a fineness of about 1-75 microns.
The finely powderedzmixture is then delivered through an air valve 158 into a chute 159 and into the inlet end of asloping-rotating drum 160 into which tobacco leaf 161 to be treated is also fed. The tobacco 161 is-fed to the drum 160 by a continuouslyv moving weighing conveyor 162. The drum 160 has internal tines that serve to agitate the tobacco and to control its rate of feed through the drum. As the tobacco enters the drum the intimate mix of finely powdered tobacco and additive materials is applied thereto so that it is agitated therewith and it adheres to the tobacco by reason of its inherent stickiness, and possibly to molecular cohesive forces. It is to be understood that the tobacco 161 to be treated is in a moist condition as it is delivered to the drum, for instance not less than about 18% moisture content, and this enhancesthe stickiness.
After treating with the finely powdered and intimately mixed additive materials and tobacco, the treated tobacco 163 is fed by means of a suitableconveyor 164 to the hopper 165 of a tobacco'cutting machine in which it is highly compressed and this presses the fine powder into close contact with the tobacco. As the tobacco is cut, stickiness below the surface of the leaf is exposed and this further assists adherence of the fine powder to the tobacco.
In a further modification, the powdered material, which may be either additive materials with powdered tobacco, or additive materials with added tobacco base adhesives recovered from tobacco, or additive materials with powdered tobacco and such added adhesives, may be forcibly applied to the tobacco, to be treated.
For instance, the finely reduced material may be delivered to a powder blower whose nozzle is directed into the rotating drum 160 so that the powder is blown onto the tobacco while it is being agitated. It is desirable in this case that the rotating drum shall be substantially a closed vessel to prevent escape of the powder. The forms of apparatus described all relate to a continuous process for applying additive materials with or without tobacco base adhesives and/or tobacco powder to tobacco, but it will be understood that it may be applied batchwise i.e. a predetermined quantity of the finely divided powder may be applied to a weighed quantity of tobacco leaf or shredded tobacco when the latter is resting in a receptacle whereupon the tobacco and powder is thoroughly agitated to mix the material together so that the powder sticks to the tobacco.
It is thought that the invention and its advantages will be understood fromthe foregoing description and it is apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the forms hereinbefore described and illustrated in the drawings being merely perferred embodiments thereof.
l. A method of treating process tobacco materials taken from the group consisting of tobacco leaves and leaf pieces and puffed tobacco formed of tobacco leaves and leaf pieces, consisting essentially of preparing treatment material consisting of finely divided discrete particles of tobacco materials substantially all of which have a size of not over 75 microns and which are in a dry condition, regulating the water moisture content of the process tobacco materials to an amount of from 17-35%, and applying said finely divided discrete particles to the process tobacco materials for forming thereon a discontinuous coating consisting of said. discrete particles, said discrete particles adhering to said process tobacco mate rials solely by reason of the inherent characteristics of said tobacco materials.
pieces, mulling said ground small pieces for reducing them to a finely divided treatment material, separating said finely divided treatment material into two grades, one grade of particles having substantially all of the particles of a size not over 75 microns and the other grade of particles having substantially all of the particles of a size greater than 75 microns, and applying said finely divided discrete particles of said one grade to the process tobacco'materials for forming thereon a discontinuous coating consisting of said discrete particles, said discrete particles adhering to said process tobacco materials solely by reason of the inherent characteristics of said tobacco materials.
3. A method as claimed in claim 2 in which said mixture is dried prior to the grinding and mulling steps to a moisture content of from 56%.
4. A method as claimed in claim 2 in which said mixture is dried during said grinding and mulling steps to a moisture content of from 5-6%.
5. A method of treating process tobacco materials taken from the group consisting of tobacco leaves and leaf pieces and puffed tobacco formed of tobacco leaves and leaf pieces, the process tobacco materials having a water moisture content of from about 17% to about 35%, consisting essentially of preparing treatment material consisting of finely divided discrete particles of tobacco materials substantially all of which have a size of not over 75 microns and which are in a dry condition, and blowing said finely divided discrete particles onto said process tobacco materials in a stream of air for forming thereon a discontinuous coating consisting of said discrete particles, said discrete particles adhering to said process tobacco materials solely by reason of the inherent characteristics of said tobacco materials.
6. A method of treating process tobacco materials taken from the group consisting of tobacco leaves and leaf pieces and puffed tobacco formed of tobacco leaves and leaf pieces, the process tobacco having a water moisture content of from about 17% to about 35%, consisting essentially of preparing a mixture of scrap and waste tobacco materials to be made into treatment material, subjecting the fragments of said mixture to the action of high velocity jets of a compressible fluid for reducing said treatment material to a dry powder consisting of particles substantially all of which have a size of not over 75 microns by effecting attrition between the fragments, and applying said powder as discrete particles to said process tobacco materials for forming on said process tobacco materials a discontinuous coating consisting of said discrete particles, said discrete particles adhering to said process tobacco materials solely by reason of the inherent characteristics of said tobacco materials.
7. A method of treating process tobacco materials taken from the group consisting of tobacco leaves and leaf pieces and puffed tobacco formed of tobacco leaves and leaf pieces, the process tobacco having a water moisture content of from about 17% to about 35 consisting essentially of preparing a mixture of scrap and waste tobacco materials to be made into treatment material, subjecting the fragments of said mixture to the action of high velocity jets of a compressible fluid for reducing said treatment material to a dry powder consisting of particles substantially all of which have a size of not over 75 microns by effecting attrition between the fragments,
.and applying said powder as discrete particles to said process tobacco materials for forming on said process tobacco materials a discontinuous coating consisting of said discrete particles, said discrete particles adhering to said process tobacco materials solely by reason of the inherent characteristics of said tobacco materials, said method further comprising compressing the thus coated process tobacco to bind the powdered treatment material into intimate contact with the process tobacco materials, and while it is thus compressed, cutting the said process tobacco materials, whereby sugars and the like contained References Cited in the file of this patent UNITED STATES PATENTS Hale Feb. 7, 1865 5 Appleby Q. Feb. 23, 1875 Rabenau Apr. 29, 1879 Kimball Apr. 5, 1881 Brooks June 26, 1888 10 Patterson Dec. 14, 1915 Bosse July 24, 1923 18 Kinker July 31, 1934 Allen Apr. 19, 1938 Andrews May 22, 1945 Sowa Aug. 21, 1951 Gurley Oct. 27, 1953 Chatelain Oct. 5, 1954 Hungerford et a1 Feb. 14, 1956 Samfield et a1 Aug. 5, 1958 FOREIGN PATENTS Great Britain AD. 1876