US3097653A - Tobacco sheet and method of making same - Google Patents

Description

July 16, 1963 Filed Jan; 27. 1958 United States Patent 3,097,653 TOBACCO SHEET AND METHOD OF MAKING SAME Gerrit de Gooijer, 15 Donkeregaard, Oudewater, Netherlands Filed Jan. 27, 1958, Ser. No. 711,464 Claims priority, application Netherlands Feb. 1, 1957 11 Claims. (Cl. 131-17) This invention relates to improved sheets or films formed from natural tobacco products and to a new method of preparing such sheets or tihns.

Manufacture of artificial tobacco leaves with paper characteristics from tobacco leaves, or preferably from tobacco waste products as stems, dust, clippings and so forth, by grinding these tobacco materials with or without addition of solvents, forming a slurry thereof with a liquid medium, and forming a web or sheet from these slurries, with or without addition of other cellulosic fibre materials, and with or without binders as the methylor ethylethers of cellulose or gelatine and so on has been the subject of many previous patent specifications and other publications.

These previous methods, insofar as other products were added to the tobacco materials, have proved to be unsatisfactory in an organoleptic respect as lacking in aroma and taste and also because the products made by these methods, generally do not show the same combustibility as natural tobacco leaves.

Insofar as these previous methods related to the manufacture of sheets containing tobacco products only, time consuming and expensive methods as heat treatment with various solvents, as water, sometimes even under pressure, were involved. These methods have moreover the disadvantage, that in these treatments with solvents at high temperature a substantial part of the tobacco materials dissolves in the solvent, so that the weight of the produced sheets is substantially less than that of the tobacco materials from which the manufacture starts.

It is known that the presence of some fibrous particles of tobacco in a slurry of fine tobacco particles in water from which a sheet is produced is not harmful in itself and may add to the strength of the finished sheet.

It was always supposed, however, that for the production of flexible and pliable sheets capable of being used in the formation of binders and wrappers of cigars, a substantial part of the tobacco particles had to be in a colloidal state. Peptiz'ing agents were added to the slurry in order to obtain these coloidal particles, or the slurry was heated to high temperatures of preferably about 125 C. It is, however, extremely difficult to produce a sheet from a slurry containing substantially colloidal tobacco particles, and therefore this process has never been accepted in practice.

It is also known to heat ground tobacco materials with water at temperatures of about 60 C. and to extract therefrom substantially all the non-fibrous material, retaining only the fibrous part of the tobacco, and to grind this fibrous product again with water with the methods which are usually applied in paper-making processes, and to produce paper-type sheets from this fibrous material only with normal paper-making machinery. This process has proved unsatisfactory because the valuable and essential properties of tobacco, such as colour, taste and aroma, are not present in the sheets produced according to such a process.

It is an object of my invention to produce films, sheets and the like from tobacco materials only which include tobacco leaves, stems, dust, clippings and so forth without any addition of artificial products as other fibrous materials or binders, although compounds which are used to improve the characteristics of natural tobacco such as salts like potassium nitrate which improves the combustibility, or minor quantities of glycerol which improve the plia'bility, may be used to improve the qualities of my films or sheets while substantially retaining in the formed film or web all the substances present in the tobacco material.

It is another object of the invention to produce a tflexible and pliable sheet material from natural tobacco products capable of being'used in the formation of binders or wrappers of cigars.

It is a further object of the invention to produce sheets from a slurry of particles of natural tobacco materials in a liquid medium, preferably water, without destroying by a heat treatment the natural characteristics of the tobacco as colour, taste and aroma.

It is still another object of my invention to produce a slurry of tobacco particles in water from which a sheet or film can be formed by a simple process, resembling usual paper-making processes.

In my process I start by grinding the tobacco into fine particles.

In the paper-making industry it is customary to indicate the degree of grinding in Schopper Riegler units. :In the paper-making industry the starting material, however, is substantially of a fibrous character, and only a very minor part consists of non-fibrous materials.

It has now appeared, that the practice of grinding to a predetermined Schopper Riegler, when applied to tobacco materials, does not give satisfactory results when sheets are prepared of the slurry of ground tobacco. This is probably due to the fact that the tobacco materials lconsist only for a minor part of fibrous materials, but mainly of materials which are of a non-fibrous nature.

Therefore I do not control the degree of grinding by the customary measurement of degrees Schopper Riegler, but by a sieving process.

To characterize the degree of grinding, I use sieves with the following characteristic:

( 1) A 100 mesh sieve, with square mesh openings of 0.21

(2) A 40 mesh sieve, with square mesh openings of 0.42

A quantity of a slurry, obtained by wetgrinding tobacco materials, is brought on one of these sieves and rinsed on the sieve with water under a pressure of one half atmosphere for 15 minutes and the residue is dried and weighed. I wetgrind the tobacco, preferably broken up to not too big parts, with water in a suitable ratio which may be from -l-5 parts by weight of tobacco to Water to l-ZO, depending on the nature of the tobacco material, until at least but not more than 95% of the dry materials passes through the 100 mesh sieve and at least 99% passes through the 18 mesh sieve. Preferably between and by weight has to pass through this 100 mesh sieve.

The part which, after a suitable milling process, is retained by this 100 mesh sieve, contains substantially all the material of a fibrous nature present in the tobacco product.

While it is possible to produce a satisfactory sheet from a slurry containing between 5% and 30% particles, which do not pass through the 100 mesh sieve more reliable results are obtained if about one-third by weight of the particles, which are retained by this 100 mesh sieve, are comparatively coarse and are also retained by the 40 mesh sieve. However, only less than 1% by weight of I V v 3 the particles may be of a size that is so coarse that they are retained by the 18 mesh sieve.

Therefore the process of the invention comprises wetgrinding tobacco materials with water to a slurry containing fine particles of tobacco which particles are of such a size that at least 70% and not more than 95% by weight of the fine tobacco particles passes through the 100 mesh sieve, and at least 99% by weight of the tobacco particles passes through the 18 mesh sieve.

In a preferred embodiment of the invention about one third by weight of the particles, retained by the 100 mesh sieve, is also retained by the 40 mesh sieve.

The grinding is preferably carried out by milling the tobacco with water in an ordinary ball mill. It is possible to use a Hollander for the milling process, but this tends to destroy the fibrous materials so that with a Hollander a slurry is obtained which contains only a minor proportion of fibres which do not pass through the 40 mesh sieve at the moment when between 5 and 30% by weight of the dry material is retained by the 100 mesh sieve.

The grinding time varies according to the quantity of tobacco material and water, the size and speed of the mill and the balls and the type of the tobacco material.

If the tobacco product is dust, generally a milling time of about half an hour will be sufiicient. For tobacco leaves and veins the milling time is somewhat longer, and for stems the time consumed in milling may be from 6 to hours. In accordance with these differences in milling time it is preferred, if a mixed slurry has to be prepared from the above different tobacco materials, to wetgrind each material separately and to mix the slurries obtained from the various tobacco products, and not to mix the tobacco materials before grinding them.

The accompanying drawing shows a schematic illustration of the method of carrying out the invention.

The reference numerals mentioned in the specification refer to the drawing.

The slurry which is made by Wetgrinding to the desired degree of milling a mixture of tobacco materials and water in a milling machine 1, preferably provided with one or more ball mills, as described above, is fed into a storage tank 2 where it is diluted further into a suspension by means of recycled liquid from a vacuum device 9, to which a quantity of water from conduit 6 may be added.

The suspension thus obtained is led to a dosing apparatus 4 with a constant level, overflow 5 and pump 3 which pumps back the overflowed suspension to the storage tank 2. i

The suspension is flowed upon a conveyer belt 8 from a slit or a number of small openings near the bottom of the dosing apparatus, said conveyor being made of a perforated band which allows moisture to pass through but hardly any solid particles.

Adjusting of the dosing is effected by means of an adjustable slide 7.

The conveyer belt passes along a vacuum device 9 which removes a considerable part of the liquid from the suspension, which liquid may be recycled to storage tank 2 for controlling the concentration of the tobacco particles of the slurry in this tank. The conveyer subsequently passes with the tobacco film through a drying tunnel 10 and a conditioning tunnel 11.

a A pump 17 brings the liquid, which has been removed from the suspension by the vacuum device, with some tobacco particles back to the storage tank.

A doctor blade 12 in a manner known in the art separates the conditioned film from the conveyer belt before the film is entirely dry.

The conveyor belt is next cleaned by an apparatus with rotating brushes 13.

After having been removed from the conveyer belt the tobacco fihn is taken over a drying device, for example consisting of a number of heated drying cylinders 14 and a supporting band 15 where the film is dried to its ultimate moisture content and is subsequently rolled on a storage cylinder 16.

Therefore the process of the invention comprises reducing in size tobacco dust, clippings, etc. by wetgrinding until 7095% by weight of the dry substance passes through the sieve having 100 meshes per straight inch, less than 1% being retained by the 18 mesh sieve, adding to the material thus obtained liquid containing recycled tobacco components obtained from the first liquid removal step which is optionally diluted with water, passing the suspension thus obtained onto a film forming surface through which liquid but hardly any solid particles will pass, the film of tobacco material obtained being separated from the film forming surface after removal of substantially all the moisture brought on the film forming surface with the tobacco particles.

This process can be carried out both continuously and discontinuou sly.

The starting material may be practically any scrap tobacco such as leaves, stems, so-called short tobacco dust, and so forth. This material is preferably reduced by wetgrinding it with water in a ball mill to the desired milling degree.

To this water may be added a small quantity of glycerol, to improve the pliability of the sheets, or a small quantity, .5 %1.5 of a salt as potassium nitrate which is generally known to improve the combustibility of tobacco leaves. However, no artificial products as other cellulosic fibres or binders and resins are added. Such additions, which are not part of the invention, are also used to improve the quality of natural tobacco leaves and are normally used to improve tobacco.

The milling time for the various starting materials varies considerably; for short tobacco dust it amounts to less than 10% of the time required for stems under similar milling conditions.

It has namely been found that in order to obtain a residue on the 100 mesh sieve of between 5 and 30% and a residue on the 18 mesh sieve of below 1%, the milling time for the fine and short tobacco dust, clippings, etc. is preferably between /3 and 1 hour and for the tobacco stems preferably between 6-12 hours, when wetgrinding in a litre ball mill with 70 balls of a total weight of 18 kg., and a revolution speed of 60 r.p.m., the ratio weight of tobacco and water for both cases being of 1 to 8.

Finally it is not necessary to start from one starting material only. It is also possible to mix suspensions prepared from various starting tobacco materials and, in order to obtain an optimal result, this is even advisable.

In the mill the ratio between tobacco and water is generally between 1 to 5 and l to 20, and preferably about 1 to 8.

After having been brought to the correct degree of milling in the mill the mass is diluted further in the storage tank.

, 'The dilution may be from 1 to 50 to 1 to 20, but preferably about 1 part by weight of tobacco to 40 parts by weight of liquid.

A dosage apparatus having a constant level, connected with the storage tank brings the diluted slurry on the upper side of a conveyer or another film-forming surface. Preferably this conveyer is a smooth metal band with about 80 openings of about 0.13 mm. diameter per inch.

If the dilution of this diluted slurry is much higher than 1:40 selective sedimentation will occur in the film; if the dilution is smaller then about 1 to 20 it is difiicult to obtain an even film.

The greater part of the water (between 80 and with dissolved tobacco components is filtered from the diluted slurry on the conveyer with a vacuum device 9, at the other side of the conveyer.

This water with tobacco components can be recycled partly or completely to the storage tank or can be used in grinding further tobacco materials. Owing to this, losses of tobacco material are obviated to a considerable veins.

extent, and simultaneously the concentration of the tobacco particles in the diluted slurry in the storage tank is kept-on substantially the same level and only a small quan tity of water has to be added.

After the bulk of the moisture from the diluted slurry has been removed by decreased pressure on the other side of the film forming surface the remaining film is further dried on this surface in a drying tunnel as shown in the drawing.

It has been found that the drying of the film on the conveyer should be terminated before the film reaches the moisture content at which it is most suitable for use in cigar-manufacture, since the film otherwise tends to stick to the conveyer, which may result in tears on removing it.

The film is therefore brought to a moisture content of between 30 and 70%, preferably about 50% by weight, in a conditioning tunnel 11, which is the most favourable condition to remove the film from the film forming surface.

The tobacco film is subsequently disengaged from this surface by means of a disengaging apparatus such as a doctor blade and is subsequently dried to the desired degree of moisture on a number of drying cylinders known from the paper industry. The finished product generally has a moisture content of about 10%.

The strength of the sheets varies according to the nature of the tobacco material started from. Generally, dust will give sheets or films of superior aroma, taste and colour, but such sheets will have only a limited strength.

On the other hand, stems give sheets or films, which have excellent strength, but the taste and aroma may be less than the taste and aroma of sheets made of tobacco leaves, or of clippings or dust.

Therefore, in producing a general purpose film, it is preferred to mix a slurry of Wetground stems and a slurry of a tobacco material mainly containing non-fibrous material so that the mixed slurry contains from about one fourth to one half by weight of ground stems or ground The film or sheet, obtained by this process, is therefore characterized in that it contains only natural tobacco prod ucts of which the natural, valuable characteristics of tobacco as colour, taste and aroma have not been destroyed, and in that it is composed of fine particles and of coarser fibrous materials, the proportion by weight of fibrous particles not passing through the 100 mesh sieve being between 5 and 30%, and the proportion of particles retained by the 18 mesh sieve being less than 1% by Weight. Preferably at least one third by weight of the fibrous particles retained by the 100 mesh sieve, should be of a size to be retained by the 40 mesh sieve.

Example I Fine and short tobacco dust, clippings, etc. were wetground in a 90 litre ball mill with 70 balls of a total Weight of 18 kg. and with a revolution speed of 60 revolutions per minute, for -half an hour. The ratio by weight of tobacco-to-water amounted to 1:8; after grinding the residue of the slurry obtained on the 100 mesh sieve was 2.7% by weight; the residue on the 40 mesh sieve was 11% by weight, while the residue on the 210 mesh sieve was below 1% by weight.

A tobacco film was made from this slurry which had excellent properties as regards taste, colour and aroma.

Example :11

Tobacco stems were wetground in the same ball mill as in Example I for 8 hours in a weight ratio of tobaccoto-water of 1:9 with addition of 1% of potassium nitrate and 0.1% of glycerol.

After grinding some very coarse parts were removed and from the remaining slurry the residue on the 100 mesh sieve was 15% by weight.

On the 40 mesh sieve, the residue was 6% by weight 6 and the residue on the 20 mesh sieve was below 1% by weight.

The tobacco obtained from the said slurry with the process of the invention had an excellent tensile strength, was, however, less satisfactory as regards taste, colour and aroma than the film produced according .to Example I.

Example IIl Fine and short tobacco dust, clippings, etc. were wetground in the same mill as in Example I for /1 hour after which the residue on the 100 mesh sieve was 9% by weight. The weight ratio of tobacco-to-water amounted to 1:8.

The residue of this slurry on the 40 mesh sieve amounted to 4% by weight and the residue on the 20 mesh sieve was less than 1% by weight.

Tobacco stems were wetground as indicated in Example II for 10 hours with a ratio by weight of tobacco to-water of 1:8.

After grinding some very coarse parts of unfibered stems were removed again.

The residue on the 100 mesh sieve of the remaining 2nd slurry was determined; it amounted to 12% by weight. The residue on the 40 mesh sieve amounted to 5% by weight, the residue on the 20 mesh sieve amounted to less than 1% by weight. The two slurries were mixed in such a way that the mixture contained about equal quantities by weight of particles of dry tobacco dust and of particles of tobacco stems.

A tobacco film obtained from this slurry was found to be very satisfactory as regards taste and colour, the tensile strength being also very satisfactory.

The tobacco film thus obtained was very suitable to be used in cig-armaking as general purpose leaf.

I claim:

1. The process of producing tobacco sheet material containing only tobacco and compounds which are used to improve the quality of tobacco leaves, comprising wetgrinding said tobacco with water in a ball mill to give .a concentrated slurry of fine particles of tobacco in water which particles are of such a size that at least 5% but not more than 30% by weight are retained on a 100 mesh sieve with square mesh openings of 0.21 mm. and at least 99% by weight of the particles of the slurry pass through an 18 mesh sieve with square mesh openings of 1.02 mm., diluting said slurry with an aqueous liquid in such a quantity that the ratio by weight of tobacco to water is between 1:20 and 1:50, forming a film of this slurry on the surface of a moving conveyor belt having very fine openings, which conveyor belt substantially retains all of the particles of the slurry, removing at least of the liquid present in said slurry through said openings in said conveyor belt, drying and recovering said tobacco sheet material.

2. The process of producing tobacco sheet material containing only tobacco and compounds which are used to improve the quality of tobacco leaves, comprising wetgrinding said tobacco with water in a ball mill to give a concentrated slurry of fine particles of tobacco in water which particles are of such a size that at least 5% but not more than 30% by weight'are retained on a mesh sieve with square mesh openings of 0.21 mm., about one "third by weight of the retained particles being also retained by a 40 mesh sieve with square mesh openings of 0.42 mm., and at least 99% by weight of the particles of the slurry pass through an 18 mesh sieve with square mesh openings of 1.02 mm., diluting said slurry with an aqueous liquid in such a quantity that the ratio by weight of tobacco to water is between 1:20' and 1:50, forming a film of this slurry on the surface of a moving conveyor belt having very fine openings, which conveyor belt substantially retains all of the particles of the slurry, removing at ieast 80% of the liquid present in said slurry 7 through said openings in said conveyor belt, drying and recovering said tobacco sheet material.

3. The process of producing tobacco sheet material containing only tobacco and compounds which areused to improve the quality of tobacco leaves, comprising wetgrinding said tobacco with Water in a ball mill to give a concentrated slurry of fine particles of tobacco in water which particles are of such a size that at least but not more than 30% by weight are retained on a 100 mesh sieve with square mesh openings of 0.21 mm. and at least 99% by weight of the particles of the slurry pass through an 18 mesh sieve with square mesh openings of 1.02 mm., diluting said slurry with an aqueous liquid in such a quantity that the ratio by weight of tobacco to water is between 1:20 and 1:50, forming a film of this slurry on the surface of a moving conveyor belt having very fine openings, which conveyor belt substantially retains all of the particles of the slurry, removing at least 80% of the liquid present in said slurry through said openings in said conveyor belt as an aqueous extract containing those particles of tobacco not retained on said conveyor belt, recycling said aqueous extract whereby said extract is added to said slurry during said diluting step, drying and recovering said tobacco sheet material.

4. The process of producin tobacco sheet material containing only tobacco and compounds which are used to improve the quality of tobacco leaves, comprising Wetgrinding said tobacco with water in a ratio by weight of tobacco to water of from 1:5 to 1:20 in a ball mill to give a concentrated slurry of fine particles of tobacco in water which particles are of such a size that at least 5% but not more than 30% by weight are retained on a 100 mesh sieve with square mesh openings of 0.21 mm. and at least 99% by weight of the particles of the slurry pass through an 18 mesh sieve with square mesh openings of 1.02 mm., diluting said slurry with an aqueous liquid in such a quantity that the ratio by weight of tobacco to water is between 1:20 and 1:50, forming afilm of this slurry on the surface of a moving conveyor belt having very fine openings, which conveyor belt substantially retains all of the particles of the slurry, applying a vacuum on the other side of said conveyor to extract at least 80% of the liquid as an aqueous extract containing those particles of tobacco not retained on said conveyor belt, recycling said aqueous extract whereby said extract is added to said slurry during said diluting step, drying and recovering said tobacco sheet material.

5. The process of producing tobacco sheet material containing only tobacco and compounds which are used to improve the quality of tobacco leaves, comprising wetgrinding said tobacco with Water in a ratio by weight of tobacco to water of from 1:5 to 1:20 in a ball mill to give a concentrated slurry of fine particles of tobacco in water which particles are of such a size that at least 5% but not more than 20% by weight are retained on a 100 mesh sieve with square mesh openings of 0.21 mm. and at least 99% by weight of the particles of the slurry pass through an 18 mesh sieve with square mesh openings of 1.02 mm, diluting said slurry with an aqueous liquid in such a quantity that the final ratio by weight of tobacco to water is between 1:20 and 1:50, forming a film of this slurry on the smooth surface of a moving metal conveyor belt having about 80 openings of 10.13 mm. diameter per straight inch, which conveyor belt substantially retains all of the particles of the slurry, applying a vacuum on the other side of said conveyor to extract at least 80% of the liquid as an aqueous extract containing those particles of tobacco not retained on said conveyor belt, recycling said aqueous extract whereby said extract is added to said slurry during said diluting step, drying and recovering said tobacco sheet material.

6. The process of claim 4, wherein tobacco dust and clippings are ground as the source of tobacco.

7. The process of claim 4, wherein tobacco stems and veins are ground as the source of tobacco.

8. The process of claim 4, wherein the tobacco being ground is selected from the group consisting of tobacco dust, tobacco clippings and tobacco leaves, containing stems and veins.

9. The process of producing tobacco sheet material containing only tobacco and compounds which are used to improve the quality of tobacco leaves, comprising wetgrinding said tobacco with water in a ratio by weight of tobacco to water of from 1:5 to 1:20 in a. ball mill to give a concentrated slurry of fine particles of tobacco in water which particles are of such a size that at least 5% but not more than 30% by weight are retained on a 100 mesh sieve with square mesh openings of 0.21 and at least 99% by weight of the particles of the slurry pass through an 18 mesh sieve with square mesh openings of 1.02 mm, diluting said slurry with an aqueous liquid in such a quantity that the ratio by weight of tobacco to water is between 1:20 and 1:50, forming a film of this slurry on the surface of a moving conveyor belt having very fine openings, which conveyor belt substantially retains all of the particles of the slurry, applying .a vacuum on the other side of said conveyor to extract at least of the liquid as an aqueous extract containing those particles of tobacco not retained on said conveyor belt, recycling said aqueous extract whereby said extract is added to said slurry during said diluting step, conveying said film first through a heated zone in which the greater part of the remaining moisture is evaporated nd next through a conditioning zone in which the moisture content of the film is adjusted to between 30% and 70% by dry weight whereby the film is readily disengaged from the conveyor, disengaging the tobacco filrn from the conveyor and drying to an ultimate moisture content of about 10%.

10. The process of claim 4 wherein said concentrated slurry of fine particles of tobacco in water are of such sizes that about one-third by weight of the particles retained on said 100 mesh sieve with square mesh openings of 0.21 mm. are also retained by a 40 mesh sieve with square mesh openings of 0.42 mm.

11. A tobacco sheet material as produced by the process of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS Re. 14,601 Rosenthal Feb. 25, 1919 86,369 Cousurega et a1. Feb. 2, 1869 257,724 Kruckemeyer May 9, 1882 346,887 Winslow Aug. 10, 1886 888,743 Rogers May 26, 1908 1,068,403 Maier July 122, 1913 2,034,784 Wallny Mar. 24, 1936 2,171,986 Poetschke Sept. 5, 1939 2,198,232 Shopneck Apr. 23, 1940 2,377,252 =Leh-recke May 29, 1945 2,433,877 Wells et a1. Jan. 6, 1948 2,485,670 Sowa et al. Oct. 25, 1949 2,570,697 Nordengren Oct. 9, 1951 2,656,841 Gurley Oct. 27, 1953 2,706,695 Frankenburg Apr. 19, 1955 12,707,472 .Turgensen et a1. May 3, 1955 2,733,720 Schur Feb. 7, 1956 2,897,103 Gottscho July 28, 1959

Claims (1)

1. THE PROCESS OF PRODUCING TOBACCO SHEET MATERIAL CONTAINING ONLY TOBACCO AND COMPOUNDS WHICH ARE USED TO IMPROVE THE QUALITY OF TOBACCO LEAVES, COMPRISING WETGRINDING SAID TOBACCO WITH WATER IN A BALL MILL TO GIVE A CONCENTRATED SLURRY OF FINE PARTICLES OF TOBACCO IN WATER WHICH PARTICLES ARE OF SUCH SIZE THAT AT LEAST 5% BUT NOT MORE THAN 30% BY WEIGHT ARE RETAINED ON A 100 MESH SIEVE WITH SQUARE MESH OPENINGS OF 0.21 MM. AND AT LEAST 99% BY WEIGHT OF THE PARTICLES OF THE SLURRY PASS THROUGH AN 18 MESH SIEVE WITH SQUARE MESH OPENINGS OF 1.02 MM., DILUTING SAID SLURRY WITH AN AQUEOUS LIQUID IN SUCH A QUANTITY THAT THE RATIO BY WEIGHT OF TOBACCO TO WATER IS BETWEEN 1:20 AND 1:50, FORMING A FILM OF THIS SLURRY ON THE SURFACE OF A MOVING CONVEYOR BELT HAVING VERY FINE OPENINGS, WHICH CONVEYOR BELT SUBSTANTIALLY RETAINS ALL OF THE PARTICLES OF THE SLURRY, REMOVING AT LEAST 80% OF THE LIQUID PRESENT IN SAID SLURRY THROUGH SAID OPENINGS IN SAID CONVEYOR BELT, DRYING AND RECOVERING SAID TOBACCO SHEET MATERIAL.

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