EP0388793B1 - Method for making tobacco shreds - Google Patents

Abstract

A method is described for making tobacco shreds from tobacco, particularly from tobacco leaves, which is supplied pressed into bales or parts thereof. <??>The invention resides in the fact that the tobacco is shredded in a tobacco shredder at a humidity of between 10% and 17% and a minimum temperature of ambient temperature (18 DEG C to 25 DEG C) without further processing.

Description

Process for producing cut tobacco from tobacco, in particular from tobacco leaves, which is delivered pressed in bales or parts thereof.

After the harvest, tobacco is dried relatively strongly, ie to a residual moisture content of about 8-11%, and is usually pressed for dispatch in cuboid or cylindrical bales or packages, although other forms of compression are also possible. The tobacco can be pure pre-stripped leaf material (without substantial rib parts); the ribs removed before drying, which are processed separately and mixed into the leaf tobacco, can also be pressed and shipped in a dry state. The pressed and relatively dry tobacco can also be stored for a long time in this condition.
Should this relatively dry tobacco be used for smoking products, e.g. B. cigarettes are processed, it is necessary in the known processing methods, the individual sheets (or leaf pieces) or ribs (or rib pieces) in the pressed bale to separate and separate from each other. Since the leaves stick together and are very dry, which makes them brittle and very sensitive to mechanical influences, they must be removed carefully. The method of loosening that is predominantly used today is to place the bale in a vacuum chamber and to supply steam through one or more mandrels which are driven in the bale, which flows outwards because of the external vacuum and warms and humidifies the tobacco, making it supple so that the leaves can be detached from each other. This method, the z. B. is described in US Pat. No. 3,372,703, is expensive in terms of equipment and additionally requires a considerable amount of energy. Subsequent to the moisture required for loosening to approx. 12 to 14% moisture, the tobacco in conventional processing systems is moistened to a cutting moisture of approx. 18 to 23% for tobacco leaves and up to 30% for ribs and cut into cut tobacco in a tobacco cutter. In modern tailors, the tobacco is compressed very strongly by means of converging press chains (one speaks of a "tobacco cake") before slices of fiber can be cut off on a mouthpiece by rotating knives. The cut tobacco must then be dried again to the processing moisture of 12.5 to 13.5%, in which it is processed into cigarettes, for example on a cigarette machine.

All of these process steps, from dissolving to high-humidification and back drying, are energy and cost-intensive.
From GB-OS 2 141 319 it has already become known to use microwaves for loosening tobacco instead of vacuum dampening systems, the adhesive forces between the tobacco parts being reduced by heating by means of the microwaves, but also in this known method the loosened tobacco leaves moistened to cutting moisture, so that the cut tobacco must then also be dried again. Thus, even in the last-mentioned process, energy is lost as a result of moistening and drying again.
US Pat. No. 4,799,501 describes a method and a plant for cutting tobacco, wherein bales of relatively dry tobacco are heated by means of microwaves and then fed to a tobacco cutter before cooling. The bales (or bale pieces thereof) have the same size in terms of width and height, for which purpose the mostly larger shipping bales first have to be divided into suitable sections.

The object on which the invention is based is to cut tobacco without a great deal of energy and equipment, and the process parameters can be selected such that good results are achieved with regard to the filling power of the cut tobacco produced.
According to the invention, this is achieved in that the tobacco is cut in a tobacco cutter at a humidity between 10% and 17% and a minimum temperature of ambient temperature (18 ° C to 25 ° C).
This cutting can be carried out in such a way that the pressed tobacco parts are not detached from one another beforehand, but rather that the tobacco, compressed into bales or pieces of bale, is fed to the tobacco cutter with its shipping moisture and room temperature and is processed by it to cut tobacco. As will be explained below, the tobacco can also be dissolved at a slightly elevated temperature and / or humidity before it is fed to the tobacco cutter. This has advantages in that the operation of the tobacco cutter becomes less problematic.
Good cutting results are obtained if the tobacco is cut in a tobacco cutter at a moisture content between 11% and 16%, preferably between 13% and 16%, for example approx. 14%.
A very advantageous moisture condition of the tobacco when cutting is to give it the moisture that the tobacco should have during further processing in cigarette machines. These are moisture values between 12.5 and 13.5%, which in exceptional cases can be slightly below or exceeded. With such moisture values, the tobacco can be cut very well directly, that is, without the damping previously thought necessary, to values between 18 and 23% moisture content. With this very advantageous cutting moisture, which is in the range of the processing moisture, the previously required dampening and drying step is eliminated. In addition, the tobacco is used less because of dampening and drying processes that mechanically stress the tobacco and lead to an undesirable fiber shortening. As already stated, a very advantageous development of the invention is that the tobacco is fed to the tobacco cutter as tobacco pressed in bales or parts thereof and cut into cut tobacco without further moistening.
The tobacco pressed in bales or parts thereof can, however, also be heated to a temperature of at least 30 ° C., preferably at least 40 ° C., for example 40 ° C. to 50 ° C., before cutting, which further improves the cutting result. At very low moisture values, i.e. at low shipping moisture values, and room temperature or very little elevated temperature, there is a loosening of the tobacco particles, e.g. B. the tobacco leaves, each other the risk of tobacco damage. Under the conditions outlined above, it is therefore advantageous to feed the tobacco to the tobacco cutter in a compressed form, ie as a shipping bale or pieces thereof. It is then important for the quality of the cut tobacco that the pieces fed have approximately the same dimensions and fill the tobacco cutter at least approximately over its width, so that the so-called press chains, which diverge conically into a press channel, are filled well and evenly. The tobacco to be cut must therefore be prepared if the pieces supplied do not exactly meet the aforementioned conditions. An improvement in this respect is brought about by a further embodiment of the invention in which the tobacco is subjected to a dissolving step immediately after a heating process and the dissolved tobacco is fed to a tobacco cutter immediately after being loosened, in which it is cut into cut tobacco.
It has been shown that sufficient release of the pressed tobacco can take place at much lower moisture and temperature values than was previously assumed. With a shipping moisture content of 11%, heating to 30 ° C is sufficient can be solved, the soldering quality gets better with increasing temperature. The term "loosening" of the tobacco in the heated bale or a part thereof does not mean that all or most of the leaves have to be released from the neighboring leaves. Although this may be the case, it is sufficient for the invention that the bales are broken up so far that the single sheets and / or smaller or larger lumps of them fill the baling chamber of the tobacco cutter between its chain in front of the cutting knives sufficiently homogeneously. If it was stated in the above that the heated tobacco should be loosened, after which the loosened tobacco is fed directly to the tobacco cutter, this means that the temperature drop during loosening and conveying to the tobacco cutter must not be so great that the Tobacco comes too cold in the tobacco cutter, because then the tobacco leaves in the tobacco cutter can be damaged by the pressing forces. Before loosening and cutting, the tobacco should therefore be warmed up to such an extent that it has a minimum temperature of 30 ° C in the tobacco cutter, but preferably about 40 ° C and above, for example between 40 ° C and 50 ° C. In this case, it is pliable enough to withstand the pressing forces.
The tobacco pressed in bales or parts thereof can advantageously be heated by exposure to microwaves or high-frequency electrical fields, as described in US Pat. No. 4,799,501. With such heating, the tobacco is not moistened at the same time.
If it is desired to wet the tobacco when it is heated, which makes it even more supple and allows it to be dissolved at considerably lower temperatures, this is possible in a manner known per se and described, for example, by US Pat. No. 3,372,703 through hollow mandrels steam is led into the interior of the bales in a vacuum. The steam flowing outwards in the direction of the vacuum warms and humidifies the tobacco leaves so that the bales can either be cut directly in the tobacco cutter without loosening or the leaves can be fed to the tobacco cutter after loosening.
A particularly good compromise between plant and energy expenditure and the quality of the cut tobacco is achieved if the tobacco pressed in bales or parts thereof is heated to a temperature between 30 ° C and 60 ° C, preferably between 40 ° C and 50 ° C, and is moistened to a moisture between 13% and 15%, preferably of about 14%. With these parameters, the energy required for heating and possibly drying is considerably less than when dampening to a relative humidity of 18% and above with conventional conditioning methods or when heating to high temperatures before cutting.
In addition, the plants for treating the tobacco with the optimal parameters according to the invention are not very expensive. Finally, undesirable taste influences of the tobacco as a result of heating to high temperatures, which must be kept for a longer period of time to dry, are avoided and good values for the filling power of the tobacco are achieved.

Damping can be done by passing saturated steam or dry steam onto the dissolved tobacco, for example while this is being conveyed on a vibratory conveyor. The steam can then be supplied from below. The tobacco temperature can be around 60 ° C after steaming, but they can also be increased to around 90 ° C.

The warm and dry cut tobacco (leaf cut, rib cut, mixture of leaf and rib cut) leaving the tobacco cutter is, preferably immediately afterwards, d. H. before cooling, moistened, which can be done in a conventional manner in a wet drum, as z. B. is described in U.S. Patent 4,054,145 or 3,948,277. According to a particularly advantageous development of the invention, the cut tobacco is moistened in a so-called steam tunnel, which has a vibrating feed channel with steam inlets and z. B. is described in US-PS 4 004 594 or GB-OS 2 138 666. The tobacco moisture can be increased in order to minimize the energy expenditure until the further processing moisture (12 to 13.5%), which the tobacco has after cooling to room temperature and with which it is processed in cigarette machines. However, it can also be moistened to higher degrees of moisture (over 20%) in order to increase its filling power, after which it is dried down to the processing moisture. The moistening preferably takes place immediately after cutting, so that the relatively dry but still warm cut tobacco reaches the moistening device before it has cooled down.

After the treatment has been completed, the tobacco fibers of different types or types of tobacco, including leaf tobacco and rib tobacco, can be mixed with one another U.S. Patent 4,116,203 is suitable.

The advantage achieved by the invention is that a method is specified how bale-pressed tobacco can be processed into usable cut tobacco with minimal use of energy and equipment, without the extensive and energy-consuming dissolving, dampening and drying equipment being used were previously considered necessary. These systems change the taste of tobacco and reduce its size.
If the tobacco is to be fed to the tobacco cutter in a dissolved form, which offers advantages for its operation, it is advantageously slightly warmed and / or moistened, for which reasonably priced systems are suitable. The energy consumption is also low. The conditioning of the tobacco for loosening can be done with little energy and with simple systems, because it has been found that the tobacco leaves do not have to be completely detached from one another, but it is sufficient if the tobacco is loosely loosened so that the tobacco cutter's pressing space is at least approximately homogeneous is filled.
If necessary, the tobacco can be fed to a steaming system before it is cut, in which its temperature and humidity are increased.

The invention is explained in more detail below on the basis of exemplary embodiments.
1. Raw Burley tobacco (tobacco leaves) with a moisture content of 8.5, 11 (shipping moisture) and 14% was cut in the pressed state with a tobacco cutter from the applicant of the KTH type. The cutting temperatures were approx. 20 ° C, 40 ° C and 75 ° C. The heating to 40 ° C and 75 ° C was carried out by exposing the tobacco to microwaves.
After cutting, the tobacco was moistened to a moisture content of 15.64% and its filling power was determined in a standard Borgwald densimeter in mm, which is widely used in the tobacco processing industry.
The following shows the relationship between the remaining height of the Borgwald densimeter and the cutting moisture or cutting temperature of the tobacco: Moisture content [%] Temperature [° C] Residual height [mm] (Borgwald densimeter) 8.5 8.5 40 34.27 8.5 75 38.63 11 20th 36.20 11 40 40.44 11 75 39.23 14 20th 39.65 14 40 42.75 14 75 39.57
2. Raw Virginia tobacco (tobacco leaves) with a moisture content of 8%, 11% (shipping moisture) and 13% was also cut in the pressed state in a tobacco cutter from the applicant of the KTH type. The temperatures when cutting were also 20 ° C, 40 ° C and 75 ° C. The heating to 40 ° C and 75 ° C was carried out by exposing the tobacco to microwaves. After cutting, the tobacco was brought to a moisture level of 12.04% and its filling power was determined in mm remaining height.
The following shows the relationship between the remaining height of the Borgwald densimeter and the cutting moisture or cutting temperature of the tobacco: Moisture content [%] Temperature [° C] Residual height [mm] (Borgwald densimeter) 8th 8th 40 36.04 8th 75 37.10 11 20th 34.26 11 40 38.23 11 75 38.26 13 20th 38.05 13 40 39.66 13 75 38.16
3. Pressed raw Virginia tobacco (tobacco leaves) with a moisture content of 8.4% (shipping moisture) was warmed and moistened from room temperature by supplying steam to it inside while in a vacuum, through a hollow mandrel. The tobacco was cut with a condition of approx. 65 ° C. and a moisture content of 11.8% by means of a tobacco cutter from the applicant of the type KTH. After cutting, the tobacco was brought to a moisture of 13%, which corresponds approximately to the processing moisture at which cigarettes are made from the tobacco. The residual height in the Borgwald densimeter was 36.31 mm at this humidity.

A similar hardness value was achieved after the leaves were separated from each other after dampening and heating and before cutting and were fed to the tobacco cutter in a loose formation.
A reference sample of the same tobacco, which had been brought to the aforementioned condition of 65 ° C. and 11.8% moisture in the same way, was first subjected to a dissolving step in which the tobacco leaves were separated from one another. After dissolving, the tobacco was moistened in a conventional manner, namely by means of a so-called steam tunnel (US Pat. No. 4,004,594) to a moisture content of 21% and cut into tobacco fibers at room temperature. These fibers were heated in a HT vibration tunnel by the applicant (GB-OS 2 138 666) to a temperature of approx. 90 ° C and were slightly further moistened and dried down to a further processing moisture content of 13% in a commercially available direct current dryer. The remaining height in the Borgwald densimeter was 34.97 mm.
It has to be emphasized that the processing of the reference sample, which the applicant has hitherto sold as the most suitable, requires three additional system parts compared to the previously described method according to the invention, namely a device for high humidification from 11.8% to approx. 21%, an HT -Tunnel for heating and expanding the tobacco at the same time as well as a DC drying drum for drying to processing moisture of 13%. These additional parts of the system are complex and require considerable energy input. In addition, the tobacco is mechanically stressed by the extraction and treatment processes.

Claims (16)

1. Method of producing cut tobacco from tobacco, in particular from tobacco leaves, which is supplied pressed in bales or parts thereof, characterized in that the tobacco is cut at a moisture level of between 10% and 17% and a minimum temperature of ambient temperature (18°C to 25°C) in a tobacco cutter.
2. Method according to Claim 1, characterized in that the tobacco, which has a moisture level of between 11% and 16%, is cut into cut tobacco in a tobacco cutter.
3. Method according to Claim 2, characterized in that the tobacco is supplied to the tobacco cutter as tobacco pressed in bales or parts thereof and is cut into cut tobacco without moistening.
4. Method according to one or more of the preceding claims, characterized in that the tobacco pressed in bales or parts thereof is heated to a temperature of at least 30°C before cutting.
5. Method according to Claim 4, characterized in that the tobacco is subjected to a loosening step directly after heating, and in that the loosened tobacco is supplied directly to the tobacco cutter, in which it is cut into cut tobacco.
6. Method according to one or more of the preceding claims, characterized in that the tobacco is heated to a temperature of 40°C or above before cutting.
7. Method according to one or more of Claims 4 to 6, characterized in that the tobacco pressed in bales or parts thereof is heated by the action of microwaves or electrical high-frequency fields thereon.
8. Method according to one or more of Claims 4 to 6, characterized in that the tobacco is additionally moistened during heating.
9. Method according to Claim 8, characterized in that the tobacco pressed in bales or parts thereof is heated and moistened in that steam is preferably passed through a hollow mandrel into the interior of the bales which are in a vacuum.
10. Method according to one or more of the preceding claims, characterized in that the tobacco pressed in bales or parts thereof is heated to a temperature between 30°C and 60°C, preferably between 40°C and 50°C, e.g. to approximately 40°C, and is brought to a moisture level of between 13% and 16%, preferably 14%.
11. Method according to one or more of Claims 5 to 10, characterized in that the tobacco is steamed after loosening for the purpose of increasing its temperature and relative moisture level and is then supplied to the tobacco cutter.
12. Method according to one or more of the preceding claims, characterized in that the cut tobacco leaving the tobacco cutter is preferably moistened directly afterwards.
13. Method according to Claim 12, characterized in that the cut tobacco is moistened to processing moisture level.
14. Method according to Claim 12, characterized in that the cut tobacco is moistened substantially beyond the processing moisture level and is then dried to processing moisture level again.
15. Method according to one or more of Claims 12 to 14, characterized in that for moistening the cut tobacco is acted upon by steam while it runs through a vibrating channel.
16. Method according to one or more of Claims 12 to 14, characterized in that the cut tobacco is moistened in a moisture drum.