US2739599A - Method of treating tobacco and tobacco products - Google Patents

Description

March 27, 1956 J. A. ABBOTT, JR

METHOD OF TREATING TOBACCO AND TOBACCO PRODUCTS Filed Dec. 31, 1948 INVENTOR JOHN A.ABBOTT JR.

ATTQRNEY lllll METHOD OF TREATING TOBACCO AND TUBACCO PRODUCTS John A. Abbott, lira, Brooklyn, N. Y., assignor to anterican Machine & Foundry Company, a corporation of New Jersey Appiication December 31, 1948, Serial No. 68,56?

8 Claims. (Cl. 131-121) This invention relates to treatment of tobacco and more particularly to a method for treating stems which have been removed from tobacco leaves, and stems and veins Which form an integral part of tobacco leaves, or parts of leaves, in such a manner that stems are converted into a form in which they can be used quite readily in smoking articles, and in the case of leaves containing stems and veins, the removal of the stems is made unnecessary because of the conversion of the stems, and particularly the large veins, into a state where they can be used in smoking articles without their removal from the leaves.

Heretofore in preparing tobacco for processing mto smoking articles, such as cigarettes and cigars, it has been necessary to remove stems either by the use of stemming machines which strip the stems from the tobacco leaves, or by the use of threshing machines which break up the leaves and thresh the stem portions and large veins from leaves or laminae, after which, by a winnowing section, the heavier stems and large vein pieces are separated from the lighter leaf or laminae parts of the leaves.

Attempts have been made in the past to utilize stems in smoking articles, such as cigars and cigarettes. Methods have been proposed for preparing them for addition to stemmed leaves and threshed leaf. A common tech nique is to crush the stems by steaming and rolling. How- States Patent 1 ever, the hard, splinty characteristics of the stems remain and are carried over into the final smoking articles where they have the unsatisfactory efiect of burning at a difierent rate. Also small, hard pieces of stems fall out of the ends of cigarettes; the tongue and fingers detect the presence of stems due to sharp points which sometimes puncture the paper wrapper. There isa deterioration in the taste of cigarettes, and the presence of hard spots makes it difiicult for the final smoking article to assume proper shape and form.

The present invention constitutes an important solution of the problem of utilizing stems and eliminating an obvious waste on the part of a manufacturer of smoking articles because it makes possible the use of stems, which in the past, except for limited quantities, have been sold as waste for manufacture into tobacco by-products, fertilizer, and other products using said stems.

According to the present invention, tobacco stems, and/or fragments of stems, and/or tobacco leaves containing stems and veins, preferably have their moisture content adjusted to a point where they contain between approximately ten and fifteen per cent moisture by weight, after which they are subjected to a high frequency electrostatic field which raises the temperature of stems and makes the stem plastic and rapidly converts water contained Within the stems and veins into steam, resulting in the radial expansion in all directions relative to their longitudinal axes of such stems and veins, and thereby effects a marked increase in volume of such stems and especially the larger veins and causes them to assume a light and fiufiy interior entirely dissimilar from their original unexpanded state.

c a. C

It has been found that stems and veins treated in the manner mentioned above can be rolled into sheets and/ or shredded into filaments and thereby converted into a form in which it can be admixed with tobacco leaf to be formed into cigarettes or cigars or other smoking articles without detracting from the desired smoking qualities of the smoking articles made from mixtures or blends containing the novel expanded stems and veins produced by the invention, and without introducing undesirable physical characteristics into the final smoking articles.

It has been proposed to expand by fluid or gas treatment the stems of tobacco while they remain in the leaf. This requires subjecting the stems while in the leaves to fluid or gas pressure and then releasing the pressure whereby stems only are expanded. This method is dis closed in Reed Patent 2,344,106, granted March 14, 1944. The present invention consists of an improved method of expanding stems which have been removed from leaves, and also stems and veins remaining in the leaves by a much simpler and better method in that the material to be expanded is not subjected to pressure or to fluid under pressure, nor to steaming with its corresponding high temperature in order to prepare it for the final expanding step as disclosed in the Reed patent.

According to my novel method, tobacco stems, and leaves containing stems and veins to be expanded are treated under normal atmospheric conditions without resort to fluid pressure or gas treatment. They are subjected to a high frequency electrostatic field for a period of time sufiicient to expand the stems, in the case where stems only are being expanded, or to expand the stems and veins in the leaves, especially the larger veins, where leaves containing stems and veins are being processed. It is'believed that the results obtained by my novel method are due to the very rapid generation of water vapor within the stems or stems and veins in leaves such that the water in the cells is converted into vapor, the resulting tremendous increase in volume causing a very rapid, almost instantaneous, buiiding up of a very high internal pressure, thereby causing the cells of the tobacco to expand greatly, thus puffing each stem heated; also the brittle stem is made substantially plastic by a rise in temperature in the presence of the moisture, enabling the tissues to stretch and expand like a balloon, rather than shatter and break into fragments. The terms stem or stems, as used herein and in the claims, include tobacco stems, and also stems and veins in tobacco leaves, especially the larger veins in tobacco leaves.

It is an object of the invention to provide a novel method for greatly decreasing the density of stems, and stems and veins in tobacco leaves and greatly increasing the ratio of surface to mass by subjecting stems and stems and veins in tobacco leaves to a high frequency electrostatic field under normal atmospheric conditions for a period of time sufiicient to expand or puff such stems.

It is a further object of my invention to provide a novel method of expanding stems radially in all directions relative to their longitudinal axes under normal atmospheric conditions without subjecting the stems being treated to fluid or gas under pressure. The method includes the subjection of stems being processed to a high frequency electrostatic field for a period of time suflicient to convert moisture, and other volatiles contained Within the stems, into vapor which results in a putting or an expansion of the stems up to several times their original diameters, usually from three to four times their original diameters, after which the expanded stems can be treated in any desired manner to convert them into forms suitable for incorporation in smoking articles, such as cigarettes and cigars.

The invention also includes tobacco leaves and portions of leaves containing stems and veins wherein the stems and veins thereof are expanded radially in all directions relative to the longitudinal axes of the stems and veins, and the leaf portions which are attached to the stems and veins, are substantially unchanged.

With these and other objects not specifically mentioned in view, the invention consists in certain features which will be hereinafter fully described, and then set forth in the claims hereunto appended.

In the accompanying drawings, which form a part of this specification, and in which like characters of refer-- ence indicate the same or like parts:

Figure l is an isometric diagrammatic and schematic illustration of a preferred method of carrying out the invention;

Figure 2 is a diagrammatic showing of a modified method of expanding stems;

Figure 3 shows a piece of stem before treatment;

Figure 4 shows the same piece of stem after treatment;

Fi ure 5 illustrates a piece of an unstemmed tobacco leaf showing some of the veins normally present in a tobacco leaf; and

Figure 6 illustrates the same piece of leaf after it has been treated according to the invention showing the expanded stern and veins.

Referring to the drawings, Figure 1 indicates diagrammatically a machine for carrying out the preferred method constituting my invention. In the mechanism shown in Figure l, tobacco stem s, and/ or leaves L, containing stems s and veins v, are delivered by any suitable conveying mechanism (not shown), or placed manually upon a conveyor 22 between spaced guides 24 suitably mounted adjacent each side of conveyor 22. It is preferred that stems s and leaves L be so arranged on conveyor 22 that they are positioned as far as possible with their longitudinal axes in a generally parallel relationship and at right angles to the plane of spaced electrodes 30, 31 in order to obtain the best results. Stems s, and/or leaves L may, however, be arranged otherwise as indicated in Figure 1, with the stems s at an angle to the plane of electrodes 39, 31, and satisfactory results are obtained.

Conveyor belt 22 runs upon spaced, driving and driven pulleys 26, 28, respectively. Driving pulley 26 may be driven by any suitable source of power, such as the main drive shaft of the machine (not shown) or it may be driven manually by a hand crank (not shown) attached to shaft 27 of pulley 26. Conveyor belt 22 is made of any suitable non-conducting type of material, preferably a material such as polytetrafiuoroethylene, which is known by the registered trademark Teflon, or other material having a low dielectric constant and low dielectric loss characteristics.

As shown in Figure l, stems s and leaves L, containing stems and veins to be expanded, are treated under normal atmospheric pressure without resort to fluid pressure, or gas treatment. When they have been arranged on belt 22, they are moved by the belt between guides 24 and thence into and through a high frequency electrostatic field between spaced vertically positioned electrodes 30 and 3.1. Electrode 30 is grounded and maintained in fixed position relative to belt 22. Electrode 31 is provided with two spaced mounts, designated generally 41, each including a support bolt 33 suitably attached to electrode 31 and a support bracket 37. Since mounts 41 are identical, it is deemed necessary to show and describe only one. Each bolt 33 extends downwardly through an elongated slot 35 in a bracket 37 suitably mounted on the frame of the machine (not shown). Bracket 37 is formed of any low loss material of good dielectric strength. A clamp nut, threadably mounted. on the free end of each bolt 33, can be turned into locking position against the underside of each bracket 37 in order to maintain electrode 31 in its predetermined operative position relative to fixed electrode 30. The reason for mounting electrode 31 for adjustment relative to fixed electrode 30 is to make it possible to vary the strength of the electrostatic field through which stems s and leaves L, containing stems s and veins v, are passed for treatment, as described in detail hereinafter. In this manner, the optimum spacing between electrodes 30 and .31 can be ascertained in advance of a run and the most satisfactory results will be achieved. Electrode 31 is connected in the operating electrical circuit by a cable 39 to a high frequency generator 32 of any suitable conventional type. For example, generator 32 can be a Vvestinghouse two kilowatt, 40.9 megacycle radio frequency generator or other similar device capable of establishing and maintaining a high frequency electrostatic field between two spaced electrodes, such as electrodes 30 and 31. Generator 32 is connected in a line from a suitable source of A. C. or D. C. current, and when switch 34 in the line is closed, the electrostatic field between electrodes 30 and 31 is established.

Prior to the delivery or placement of stems s, and/or leaves L on belt 22, they are subjected, if necessary, to moisture control in order to adjust the moisture content of the stems, and the stems and veins in leaves to be treated. It has been found that good results are obtained when the moisture content ranges between 5% to 20%, the optimum moisture content being between approximately 10% and 15%. As the moisture adjusted stems and/ or leaves. containing stems and veins are moved by conveyor belt 22 between electrodes 30 and 31 and thereby subjected to the influence of the high frequency electrostatic field established therebetween, the stems, and stems and veins are rapidly heated internally to such an extent that they swell and expand radially in all directions relative to their longitudinal axes resulting in an increase in diameter of the stems, and stems and veins in leaves up to several times their original diameters, and usually from three to four times their original diameters. Another way of stating the change effected in accordance with the invention is that of the volumetric increase of puffed stems. If for example the diameter of a given stem is increased three times its original diameter, it follows that its volume is increased nine-fold. This may be shown as follows: The original volume of a stern one unit long is:

The final volume of the same stem when its diameter is increased three times is:

In the above equations:

V1 is the original volume of a stem one unit long.

V2 is the final volume of the expanded stem.

Pi denotes the ratio of the circumference of a circle to its diameter (value of Pi=3.1416).

D is the original diameter of an unputfed stem; and

3D is the final diameter of a stem having diameter D increased three times.

Hence a stem whose diameter is increased three times, has its volume increased nine times, or 900%. It is also apparent from the above that if a stem has its diameter increased four times by expanding, its volume is increased sixteen (16) times, or 1600%.

Figure 3 indicates a stem s before being treated in the manner described. Figure 4 designates the same stern S after being treated. Figure 5 illustrates a piece of a leaf containing a stern s and veins v-, and Figure 6 indicates the same piece of leaf showing the expanded stem S and expanded veins V. As stated hereinabove, it is believed that as the stems s and leaves or pieces of leaves L containing stems s and veins v are subjected to the high frequency electrostatic field and dielectrically heated, a very rapid generation of water vapor within the stems s and stems s and veins v takes place such that the water in the cells of the stems and veins is converted into vapor, causing a tremendous increase in volume due to a very rapid, almost instantaneous building up of an internal pressure which puffs each stem s, s and vein v, especially the major veins of a leaf, to the forms designated generally at S, S and V.

Conveyor driving pulley 26 can be driven intermittently to advance conveyor 22 step by step into and through the electrostatic field, or conveyor driving pulley 26 can be driven continuously at a predetermined speed in order to move the material being treated with a continuous motion through the electrostatic field between electrodes 30 and 31. Expanded stems S and leaves containing expanded stems S and veins V are delivered by conveyor 22 into a suitable receptacle 40 from which they are removed for processing for use in smoking articles, such as cigarettes and cigars.

As mentioned hereinabove, it is preferred to arrange the stems and leaves being treated with the longitudinal axes thereof lying generally in planes substantially-at right angles with the planes of electrodes 30, 31. In placing stems, and/or leaves containing stems, on the travelling surface which moves them between the spaced vertical electrodes, it is preferred to arrange them with their longitudinal or major axes in substantially parallel relation, as far as possible, in such manner that the longitudinal axes of the stems and/or leaves containing stems and .veins are normal to the plane of the electrodes. When stems and/or leaves containing stems and veins are positioned in this manner, the elongated fibres of the stems are substantially parallel to the lines of force of the electrostatic field. Because of this, the lines of force do not bridge the air spaces in the stems. n the other hand, if the stems and/or leaves are arranged at an angle to the plane of the electrodes, or more especially at right angles to; the lines of force of the electrostatic field, the field bridges the air spaces and can cause a local breakdown thereof with a concurrent arcing and burning of the expanded stems and veins, which is undesirable. Due to the movement of stems and leaves into and through the electrostatic field, certain stems react more ripidly than others and reach their desired expanded condition before others do. This is not a disadvantage, however, because as soon as a stem s or s reaches condition S or S, all further expansion ceases as does the heat treating thereof and no further action is caused thereon 'by the electrostatic field. This same condition obtains in connection with veins v of leaves when they reach the expanded condition V. This means that as the stem s and leaves or pieces of leaves containing stems s and veins v travel through the electrostatic field, the expanding action with respect to all expandable tobacco material may vary, but due to the fact that it is preferred to use relatively elongated electrodes 30, 31, and a speed which will allow all stems passing there through to be subjected to the electrostatic field for a period ranging between one second and five minutes, I have found that all stems passing out of the electrostatic field will be expanded satisfactorily with a minimum of scorching. In connection with the latter, due to the provision of means for properly locating the stems and leaves on belt 22, preferably so that the ends of the stems and leaves do not touch both electrodes, flashing is substantially eliminated. While a period of time from one second to five minutes is mentioned, it is to be noted that best results have been obtained in a period ranging from one second to thirty seconds. In order to insure that belt 22 is clean at all times from tobacco dust or other accumulations of unwanted material thereon which might cause a fiashover between electrodes 30, 31, there is provided a rotary brush 42, suitably mounted beneath the lower lap of belt 22 and engaging therewith, as shown in Figure 1. Brush 42 may be driven in any desired manner (not shown) from the main drive shaft (not shown) on the machine.

Figure 2 shows a modified method for carrying out my invention. The mechanism indicated diagrammatically in this figure consists of a pair of vertically spaced electrodes 80, 81. Electrode is attached to an adjustable mount of suitable non-conducting material having a low dielectric loss. Electrode 81 is fixed and mounted beneath the upper lap of an endless conveyor 82 travelling on driving and driven pulleys 84, 86, respectively. Belt 82 is of a width suitable to support stems and leaf portions of desired lengths as they are travelled thereby through a high frequency electrostatic field established when a current, generated in high frequency generator 32, is conducted through cable 39 to electrode 80 and the desired field is established between electrodes 80, 81, the latter being grounded. Belt 82 may be formed of the same material as belt 22, described hereinabove. It can be driven intermittently or continuously as preferred so long as the stems and leaves containing stems and veins are positioned in the electrostatic field between electrodes 80 and 81 for a period of time sufiicient to puff or expand all of said stems S and S' and veins V in leaves or portions of leaves being treated. As in the method described in connection with Figure 1, in general it is preferred not to rely solely on the moisture content of stems s and/or stems s' and veins v in leaves or portions of leaves containing stems and veins. Therefore such material being treated in accordance with the method described in Figure 2 preferably is subjected to moisture control as at 20 in Figure 1, in order to establish a predetermined optimum moisture content which is approximately between 10 and 15%. Expanded stems S and leaves containing expanded stems S and veins V, are discharged from conveyor 82 into a suitable receptacle 88 from which they are removed for further processing into smoking articles such as cigars and cigarettes.

In the methods described hereinabove, endless belts are shown as the means for positioning tobacco stems and/or leaves or pieces of leaves containing stems and veins in the high frequency electrostatic field. Obviously, if desired, tobacco to be treated could be placed manually or delivered by suitable means onto a suitable surface which would support them for the desired treatment in the high frequency electrostatic field. By means of a line switch, such as switch 34, current to a high frequency generator, such as generator 32, could be controlled in order to establish and maintain the high frequency electrostatic field for the period of time required to secure the desired puffing.

In the case of expansion of veins in leaves or par-ts of leaves containing stems and veins, it is noted that the veins which expand or puff generally are the larger or main veins, especially those connected to the stem.

The invention above described may be varied in construction within the scope of the claims, for the particular embodiments selected to illustrate the invention are but a few of the possible concrete forms which my invention may assume. The invention, therefore, is not to be restricted to the precise details of the structures shown and described.

What I claim is: l

l. The method of processing tobacco stems under substantially normal atmospheric conditions which comprises subjecting tobacco stems having a moisture content of from 10% to 15%, to a high frequency electrostatic field, and maintaining said stems in said field for from one second tothirty seconds to cause the temperature of said moisture contained in said stems to be raised to at least 212 F. with an almost instantaneous building up of an internal vapor pressure within the cells, thus effecting pufiing of the cells and escape of steam therefrom, the

stems immediately assuming a form having a final volume several times the original volume of said stems in the unpuffed state.

2. The method of processing tobacco stems under substantially normal atmospheric conditions, which comprisessubjecting tobacco stems having a moisture content between and under normal atmospheric pressure to a high frequency electrostatic field and while holding said stems in said field, heating said stems in said field to cause the moisture contained therein to be raised to at least 212 F. with an almost instantaneous building up ofan internal vapor pressure within the cells, thus effecting putting of the cells and escape of steam therefrom, said stems immediately assuming a form having a final volume at least twice the original volume of said stems in the unpuffed state.

3. The method of expanding tobacco stems and stems and veins in tobacco leaves, which comprises adjusting the moisture content in said stems, and stems and veins in said leaves to between approximately 10% and 15% by weight, and subjecting said stems, and leaves containing stems and veins under substantially normal atmospheric conditions to a high frequency electrostatic field for from one second to thirty seconds to raise the temperature of said moisture to at least 212 F. with an almost instantaneous building up of the internal vapor pressure within the cells, thus effecting pufiing of the cells and escape of steam, said stems and veins immediately assuming a form having a final volume .at least twice the original volume of said stems and veins in the unpulfed state.

4. The method of expanding tobacco stems, which comprises adjusting the moisture content in said stems to between approximately 10% and 15% by weight, arranging said stems with the longitudinal axes thereof in substantially parallel arrangement, and then subjecting said stems under substantially normal atmospheric conditions to a high frequency electrostatic field for from one secend to thirty seconds while moving said stems through said field to raise said moisture to a temperature of at last 212 F. with an almost instantaneous building up of an internal vapor pressure within the cells, thus effecting a puffing of the cells and escape of steam therefrom, said stems immediately assuming a form having a final volume at least twice the volume of said stems in the unpuffed state.

5. The method of treating tobacco stems, which comprises humidify-ing said stems to a moisture content containing between 10% and 15 by weight of said stems, arranging said stems on a supporting surface with the longitudinal axes thereof extending substantially transversely of the length of said surface, locating said surface with said stems under substantially normal atmospheric pressures in a high frequency electrostatic field with the longitudinal axes of said stems substantially at right angles with the source of said high frequency electrostatic field, moving said stems through said field and maintaining said stems within the range of action of said dielectric field for a period of time ranging between one and thirty secends to cause the temperature of volatile substances contained in said stems, including said moisture in said stems, to be raised to at least 212 F. with an almost instantaneous building up of an internal vapor pressure within the cells and escape of steam therefrom, said stems immediately assuming a form having a final volume at least twice the original volume of said stems in their unpuffed state.

'6. Themethod of expanding tobacco stems, which comprises adjusting the moisture content therein to between 10% and 15% by weight, placing said stems on a nonconducting surface, subjecting said stems on said surface to a high frequency electrostatic field and maintaining said high frequency electrostatic field on said stems to cause the temperature of said moisture to be raised to at least 212 F. and convert said moisture and volatile constituents contained in said stems to a gaseous state with an almost instantaneous building upof an internal vapor pressure within the cells, thus effecting puffing of the cells and an escape of steam and volatile constituents therefrom, said stems immediately assuming a form having a final volume atleast twice the original volume of said stems in their unpuffed state. V

7. The method of expanding tobacco stems, and stems and veins of tobacco leaves, comprising humidifying said stems, and said leaves containing said stems and veins until: said stems and veins contain approximately 10% to 15% moisture, positioning said humidified stems, and said leaves containing stems and veins between spaced electrodes, and while said stems and leaves are located betweensaid electrodes and free from contact therewith, passing a current through said electrodes to establish a high frequency electrostatic heating field between said electrodes for from one'second to thirty seconds and caus ing the heat generated by said field to cause the temperature of moisturecontained in said stems and veins to be raised to at least 212 F. with an almost instantaneous building up of an internal vapor pressure within the cells, thus effecting pufiin'g of the cells and the escape of steam therefrom, said stems and veins immediately assuming a form having-a final volume at least twice the original volume of said stems and veins in their unpufted state.

8. The product made by the method defined in claim 1.

- References Cited in the. file of this patent UNITED STATES PATENTS 240,252; ..,Huck, Apr. 19, 1881 643,193 Lorillard'et 'al. Feb. 13, 1900 1,224,703 Benjamin May 1, 1917 1,789,435 Hawking Jan. 20, 1931 2,064,522 Davis Dec. 15, 1936 2,124,012 Smith July 19, 1938 2,344,106, Reed Mar. 14, 1944 2,379,117 Touton June 26, 1945 2,500,752 Hanson et al. Mar. 14, 1950 FOREIGN PATENTS 361,301 Great Britain May 13, 1930 499,764 Great Britain Jan. 27, 1939 OTHER REFERENCES Ser'. No. 340,214, Bohme (A. P. C.) published May 11, 1943.

Textbook of Botany, by J. M. Coulter, C. R. Barnes, and H. C.;Cowle's. Published 1910 by American Book Co., New York. Pages 250, 342 and 343.

" G. S Avery; American Journal of Botany, vol. 20, 1933. Page 586.

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