US 3373751 A
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Description (OCR text may contain errors)
March 19, 1968 A. w LLLLL RG 3,373,751
OB CC DUST AND WASTE Fi l e d 0 c t l 3 1 9 64 FIG.1
ABSTRACT OF THE DISCLOSURE Method for producing shaped masses of tobacco from waste tobacco including milling the waste tobacco in the presence of water for a time sufficient to destroy the cell walls of the tobacco without materially reducing the fiber length, and to hydrate and fibrillate cellulose content thereof, and thereby produce a paste-like mass. An inert gas is passed through the mass during the milling and is removed prior to shaping. Thereafter the paste-like mass is shaped into helical strings or thin filamentous web by extrusion through a nozzle having a plurality of passages, the wall of each passage at its mouth having (1) a projecting point which defines only part of the circumference of the mouth of the passage or (2) an insert which defines only part of the circumference of the mouth of the passage and has a friction coefficient which differs materially from that of the remainder of the mouth of the passage.
This invention relates to a method in utilizing and refining tobacco dust and other waste tobacco which is subject to a disintegrating, mechanical treatment in the presence of water.
The method according to the invention is characterized primarily in that the disintegration is carried out in such a manner, that, on the one hand, the cell walls of the tobacco are destroyed without having their fibres materially reduced in length, and, on the other hand the cellulose comprised in the tobacco is hydrated and fibrillated thereby forming a paste-like, fibrous, plastic mass which is shaped, under pressure and without substantial separation of water, into a thin, preferably filamentous web, and dried. During the fibrillation the fibers of a fibre bunch are freed or separated from each other without appreciable reduction of their length. This may be brought about by milling or grinding the tobacco, not too finely, so that the surface layer of the fiber is split or destroyed in such a way, that very fine filaments or fibrils are formed of preponderantly integral, filamentary parts of the surface layer of the fibre. The essential meaning of the word hydration is the swelling of the fibre which brought about by mechanical treatment, such as beating, in the presence of water in connection with the splitting up of the surface layer, and the hydrogen bonds which form between individual fibers when the hydration water is dried off. Thanks to the presence of fibres which serve as a skeleton, and their fibrils which hook onto and engage the fibrils of adjacent fibres a cellulose product is obtained which has a good mechanical strength or tenacity which is further improved by the hydration in which there is obtained, on account of the presence of low-molecular hemicelluloses, a gel which acts as a short of glue between the cells. On account of the above circumstances it is possible to form this cellulose product into a filamentary or filmshaped web which exhibits porosity and other characteristics of paper when dried.
If the fibres are greatly shortened by a disintegration which is too extensive (fine-grinding)- so that colloidal particles are formed and only short fibre fragments are left, the fibres lose their capability of forming skeletons id States atent which has the disadvantage, that the paper structure and consequently the tenacity and the porosity may be lost. Hydration of cellulose has a maximum which can easily be passed and after which the hydration appears to fall rapidly. In order to maintain the fibre formation of the tobacco parts it is therefore necessary to carry out the disintegration very carefully and not to continue it too extensively. The length of the tobacco fibres should be of the order of 1 mm. even after the disintegration. Here, the expression mechanical treatment is intended to comprise even such cases as subjecting the tobacco to pressure impulses e.g. from fluids or gases or the ultra-sound, instead of pressures, blows or impulses from solid bodies.
A nozzle may be utilized in the practice of this invention when it is desired to form filaments by extrusion of the plastic mass and which comprises a number of through passages for said mass. The nozzle according to a preferred embodiment is primarily characterized in that the wall of each passage at its month has a projecting point which defines only part of the circumference of the mouth of the passage.
By the utilization of the method and the nozzle according to the invention it is possible to produce tobacco which is directly utilizable as cigarette, cigar or pipe tobacco without any further treatment operations subsequent to the drying, and which contains no extraneous substances not comprised in natural tobacco.
The tobacco mass, to which a small amount of binder may have been added to reduce the risk of raising the dust, suitably contains about 20-80%, preferably between 40% and 60%, of water at the mechanical treatment. The permissible amount of water increases together with the proportion of binder. The quantity of water should be sufiicient for hydration and so great, that the mass gets a plasticity which permits its forming by extrusion through nozzles.
The proportion of water must not, however, be so great, that the water separates from the tobacco on account of the forming or extrusion pressure or that tobacco filaments formed stick together and lose their shape when drying. The tobacco mass as Well as the filaments or the like should, in other words, he self-supporting, i.e. small pieces of the tobacco mass should not lose their shape under the influence of their own weight.
The treatment of the tobacco may be carried out either in air or in another gas in open or in closed apparatus, and at partial vacuum, at atmospheric pressure or at elevated pressure. Since the taste of tobacco is deteriorated by air oxidation, the treatment may preferably be carried out in an inert protective gas, e.g. nitrogen gas or carbon dioxide. In those instances when tobacco having less satisfactory taste is to be refined, the treatment may be carried out under air ventilation or gas exchange, during which substances which deteriorate the taste of tobacco are carried off. The treatment is preferably carried out in a closed grinding or milling container from which air is evacuated after that tobacco, water and possible binder have been introduced. During the disintegration operation the protective gas is then fed with a suitable pressure through the disintegration container. Before the forming in the forming tool, the tobacco mass should suitably be freed from gas, the gas in the disintegration container being evacuated until a sufficient vacuum has been attained, since worked-in gas would otherwise become compressed by the forming pressure and burst the tobacco product at its passage out of the forming tool, in which the pressure is high, to the surrounding atmosphere. The tobacco mass, created by the treatment and containing hydrated and fibrillated cellulose and sticky vegetable cellsubstance acquires such a structure and consistency, that it may be pressed or extruded through forming tools, such as stationary or rotating nozzles of suitable shape. Possibly, at least a small fraction of the hydration and fibrillation described above is brought about in the forming tool by the high pressure to which the watery, fibrous tobacco mass is subjected therein.
In the accompanying drawing, there is shown diagrammatically and as non-limiting examples and on an enlarged scale two embodiments of nozzles which are suitable for the extrusion of the tobacco mass. Tobacco filaments extruded through such nozzles obtain a substantially helical shape.
FIGS. 1 and 2 are a longitudinal section on line II in FIG. 2 and a transverse section on line IIII in FIG. 1 respectively through a nozzle according to the invention.
FIGS. 3 and 4 illustrate in the same Way a modification of the nozzle according to FIGS. 1-2.
The nozzle according to FIGS. 1-2 is suitably comprised of two halves 1a, 1b united substantially along an axial plane. The nozzle is provided with channels 2 having a reduced opening and through which the tobacco mass is extruded under high pressure. The wall of the mouth of the respective channels has a projecting point 3 which defines only part of the circumference of the mouth of the channel. Through this design of the nozzle the tobacco mass is formed at the extrusion into a number of substantially helical tobacco strings or filaments.
The embodiment illustrated in FIGS. 34 is in agreement with that shown in FIGS. 12, apart from the modification, that the points 3 have been replaced by inserts 4 of a material having a friction coefiicient which differs materially from that of the material defining the remainder of the mouth of the channel 2. The inserts 4 could be either smoother or rougher than the adjacent material. If it should be desired to make tobacco filaments which are straight instead of helical, the points 3 and inserts 4 are simply omitted. FIGS. 1-4 are not to be construed as drawn on an accurate scale. Thus, the points 3 and the inserts 4 may define a greater or smaller portion of the mouth of the respective channels 2.
Instead of being pressed out or extruded, the tobacco mass may possibly be rolled or formed in another way into tobacco films which are subsequently disintegrated in a conventional manner. When the tobacco string or film thus formed is subsequently dried, it acquires sufiicient tenacity.
The embodiments described above and shown in the drawings are, of course, to be regarded merely as nonlimiting examples and can be modified in several ways as to their details, within the scope of the following claims. The nozzles shown and described may thus be utilized for the extrusion of plastic masses other than those containing hydrated and fibrillated waste tobacco.
What I claim is:
1. In a method of utilizing and refining tobacco waste, the steps comprising wet grinding said tobacco waste in a closed container with water present in amount of 20-80 weight percent for a time suflicient such that the cell walls of the tobacco are destroyed without having their fibers materially reduced in length and such that the cellulose content of said tobacco waste is hydrated and fibrillated thereby forming a paste-like, fibrous plastic tobacco mass, evacuating gas present in said container during the initial stage of said Wet grinding, then passing an inert protective gas through said container and said plastic tobacco mass during said wet grinding, forming said mass under pressure after removal of the said inert gas without appreciable separation of the Water from the mass into predetermined shape and drying said shaped tobacco mass.
2. A method according to claim 1 wherein said mass is formed under pressure into thin substantially helical filaments.
3. A method according to claim 1 wherein said water is present in amounts of 4060 weight percent.
References Cited UNITED STATES PATENTS 2,613,673 10/1952 Staxtoretto et al. 3,020,179 ,2/ 1962 Hess. 3,097,653 7/ 1963 Gooijer. 3,194,245 7/ 1965 Clarke 131-140 3,203,432 8/1965 Green et al. 3,215,760 11/1965 Grace et al. 3,125,098 3/1964 Osborne 13117 FOREIGN PATENTS 20,395 1911 Great Britain.
SAMUEL KOREN, Primary Examiner.
MELVIN D. REIN, Examiner.