EP0074534A2 - Continuous two-stage process for the expansion of comminuted tobacco - Google Patents

Abstract

The invention relates to a method and a device suitable for carrying out the method for increasing the volume (puffing) of comminuted tobacco, which is impregnated with an impregnating agent containing at least water to an initial moisture content of at least 35 percent by weight and with a heating medium containing gaseous water vapor up to a final moisture content of 10 to 13 weight percent is brought, the total process time being at least 10 seconds. The process according to the invention is distinguished by the fact that it is carried out as a continuous two-stage process in which, in the first stage of the process, the impregnated tobacco is brought under puffing conditions to a moisture content which is reduced by about 5 to about 60% compared to the initial moisture content. In the second stage of the process, the tobacco is flowed around and / or moved mechanically by the heating medium and / or mechanically under reduced process conditions compared to the puffing conditions, to a final moisture content of about 10 to 13 percent by weight. The device suitable for this has a first part of the device for carrying out the first process stage, which is followed by a second device part with a continuous or discontinuous transition, in which the second process step takes place.

Description

The invention relates to a method according to the preamble of the main claim and a device intended for carrying out the method.

Methods and devices suitable for carrying out these methods are already known, with which the fillability of cut and impregnated tobacco can be improved by heating with a gaseous heating medium. In order to improve the filling capacity of cut tobacco ribs, an impregnation with water is sufficient, while with cut tobacco laminas an inorganic or organic impregnating agent that boils and / or volatilizes at low temperature is used.

From GB-PS 14 09 825 it is known to bring about an increase in volume of the impregnated tobacco through a rapid change in pressure in the surrounding environment. However, this batch process is very uneconomical.

If air or an inert gas without significant moisture content is used as the heating medium to increase the volume (US Pat. Nos. 3,409,022, 3,409,023), there are crusts on the outer surface of the tobacco cut, which give an elastic yield to the outer cells or cell walls and one prevent successful tobacco expansion.

The importance of the contact time of the heating medium with the tobacco during the process of increasing the volume becomes clear judged differently. In US Pat. No. 3,357,436, an extraordinarily long contact time using several drying towers is emphasized, but only fill capacity improvements of approximately 2.3% result. In a method known from US Pat. No. 3,734,104 or the corresponding DE-PS 22 53 882, moist and cut tobacco ribs are dried over a contact time of 0.5 to a maximum of 3 seconds in a gaseous, steam-containing heating medium, and that very quickly down to a moisture content of 6%, which initially results in an approximately 50% improvement in filling capacity. The heating medium that transports and dries the tobacco flows at a speed of approx. 40 m / s. In order to achieve the desired contact or dwell time, this high speed requires correspondingly long pipelines with a considerable pressure drop and a correspondingly high expenditure of energy. In particular in the bends of the pipes and when the tobacco is separated from the heating medium, tobacco breaks and the associated waste cannot be avoided to a greater extent. The extremely heavily dried tobacco becomes very brittle and loses quality. In addition, it must be brought to the usual moisture content of 12 to 13% before further processing, as a result of which the initially given improvement in filling capacity is greatly reduced again, unless complex measures are provided to prevent this.

A similar procedure is followed in EPA 0029 588, where the impregnated tobacco is expanded and allowed to dry in a pipe string provided with 90 ° bends from the rapidly flowing heating medium in a maximum of 3 seconds before it is separated from the heating medium in a separating device. A strong embrittlement, a big Ab The proportion of cases and a deterioration in quality can hardly be avoided.

According to US Pat. No. 3,881,498, the tobacco is moved in a vibrating fluidized bed. Heating medium flows in through perforations. The gas flow rate is limited by the floating speed of the tobacco particles, which worsens the puffing effect. Flow channels are created in the tobacco mass, which lead to an uneven distribution of moisture and an uneven puffing.

In all of these known and uneconomical processes, in which the initial moisture content is above 35%, the volume is increased in a continuous process step with practically unchanged conditions. Cyclones are used to separate the air from the tobacco and / or for uniform drying. The final moisture content after such drastic processes is around 2%, since the extreme puffing conditions are maintained even when drying. This affects the final quality of the tobacco and increases waste.

US Pat. No. 4,044,780 describes a gas inlet tube for transporting tobacco in warm, humid air. The pipe is provided with an indentation in front of the outlet end in order to accelerate the flow and increase turbulence. Although this leads to better heat transfer during drying, at the same time it results from the fact that the tobacco particles in a largely dried state at an increased speed through the

Turbulence and flow diversion suffer more fracture, which limits the improvement in filling capacity and generates a high proportion of dust.

The invention has for its object to provide a method of the type mentioned and a device suitable for carrying out the method, with which the volume increase of the impregnated tobacco is carried out much more gently than the known methods until a high filling capacity improvement for the tobacco is achieved was possible. With this gentle treatment of tobacco, there should be as little waste as possible and there should be no noticeable deterioration in quality.

The object is achieved according to the invention by the method features specified in the characterizing part of the main claim. Surprisingly, it has been shown that over 80% of the increase in volume is achieved in the first process stage, after which the moisture content has only decreased by 5 to 60%. The further treatment of the tobacco in the second stage of the process then takes place much more gently only up to the final moisture content necessary for further processing, with the gently treating the then increasingly drying tobacco _{reducing waste} and largely preventing a deterioration in quality. Because the linear speed and the temperature of the heating medium are significantly reduced in the second process stage, both the energy consumption for the process and the breakage formation in tobacco are reduced.

In the method according to the invention, tobacco is treated in the form of cut tobacco ribs and / or cut tobacco leaves, either individually or mixed together.

The method features of claim 2 are important for achieving a good puffing effect. During the first stage of the process, so much heat must be transferred to the tobacco in a very short time that the impregnating agent evaporates inside the cells before any significant drying of the cell surfaces or cell walls takes place. The moist tobacco can withstand these speeds without damage.

On the other hand, the features of claim 3 are favorable for the second stage of the process, where the tobacco is treated under conditions which have been tempered in this way and in view of its increasing drying. The thermal and mechanical stress on the tobacco is thus noticeably reduced in the second process stage compared to the first process stage. The energy consumption is also lower.

In order to keep the effect of the process on the tobacco precisely dosed, the feature of claim 4 is also essential. The tobacco is gently dried over 9/10 of the duration of the process.

In order to prevent changes in taste by the method according to the invention, it is expedient to treat the tobacco with an impregnating agent according to claims 5 and / or 6. Aluminum sulfate in particular leads to improved ultimate stability against collapse in cut tobacco leaves, while water is an inexpensive impregnation agent.

The best results are achieved if the substances are used in a proportion according to claim 7 or with regard to tobacco lamina according to claim 8.

The process feature of claim 9 is also important so that the volume increase to the desired, large extent is achieved in the first process stage.

For the gentle treatment of the tobacco in the second stage of the process, the temperature drop specified in claim 10 ensures.

The tobacco is subjected to both process stages in the respectively predetermined manner if the process features of claims 11 and 12 are taken into account.

As an alternative to this, the method feature of claim 13 in the second method stage can also be advantageous, since, due to the reduced thermal load, the tobacco can also tolerate mechanical movement without any noteworthy damage.

The transition from the first process stage to the second process stage can be either continuous or discontinuous. With both alternatives according to claims 1 ⁴ and ¹ 5 it only has to be ensured that after the first process step the treatment for the tobacco actually takes place in a softer form.

In practice, it has proven to be expedient to observe the process feature of claim 16, since with such a total process time an acceptable energy expenditure is sufficient to achieve a high output.

The method according to the invention can expediently be carried out in a device as explained in claim 17. The desired dwell or contact time between the tobacco and the heating medium explained at the outset is exactly achieved in the pipe system, a uniform heat transfer to all tobacco particles and nevertheless a gentle movement of the tobacco being ensured.

The mixing of the tobacco with the heating medium is particularly refined if the features of claim 18 are realized.

Another useful embodiment of an apparatus for performing the method according to the invention is specified in claim ₁₉ . After the end of the first process stage, the tobacco is passed through the cross-sectional expansion into the drying device, in which it is then treated more gently than in the pipe system. Appropriately, according to claim 20, the drying device is formed by a specially designed shaft or, according to claim 2 _1, by a drum dryer.

Alternatively, according to Claim 22, a multi-belt dryer is also expedient for the gentle treatment of the tobacco in the second process stage, in which case the tobacco is moved mechanically through the second process stage.

In order to obtain an exact separation between the two process stages, it is further advantageous according to claim 23 to arrange a separating device.

Furthermore, according to claim 24, a drum dryer can also be used for carrying out the method according to the invention, which has a cross section that increases in the flow direction, the first process stage taking place in an initial part of the drum dryer and the second process stage with a gentler one in the second part of the drum dryer with an increasing cross section Treatment of tobacco is carried out.

The feature emphasized in claim 25 is particularly expedient, according to which the drum dryer is subjected to a uniform flow of hot and humid air transversely to its axial direction.

Furthermore, claim 26 is directed to a further embodiment of the aforementioned device for carrying out the method according to the invention, in which the cross-sectional enlargement of the drum dryer is adapted to the fact that the tobacco becomes increasingly drier on its way through the drum dryer and therefore has to be treated with increasing care. Um = the larger the cross-section of the drum dryer is, _the t _o is the temperature and the velocity of the heating medium is reduced the more.

In addition, a further device can be used, as explained in claim 27, and in which the tobacco is predominantly moved mechanically.

Finally, claim 28 is directed to a further advantageous embodiment of such a device, which is particularly simple and powerful.

• Fig. 1 eine schematische Seitenansicht einer ersten Ausführungsform einer Vorrichtung,
• Fig. 2 eine schematische Ansicht einer zweiten Ausführungsform einer Vorrichtung,
• Fig. 3 eine schematische Seitenansicht einer dritten Ausführungsform einer Vorrichtung zum Durchführen des erfindungsgemäßen Verfahrens,
• Fig. 4 eine schematische Ansicht einer vierten Ausführungsform der Vorrichtung,
• Fig. 5 eine fünfte Ausführungsform, und
• Fig. 6 und 7 eine sechste Ausführungsform in zwei zueinandergeordneten Schnitten.

Show it

• 1 is a schematic side view of a first embodiment of a device,
• 2 shows a schematic view of a second embodiment of a device,
• 3 shows a schematic side view of a third embodiment of a device for carrying out the method according to the invention,
• 4 shows a schematic view of a fourth embodiment of the device,
• Fig. 5 shows a fifth embodiment, and
• 6 and 7 a sixth embodiment in two mutually arranged sections.

The method according to the invention for increasing the volume (puffing) of tobacco, in particular cut tobacco ribs and / or cut tobacco leaves, is carried out in a device which is indicated in various embodiments in FIGS. 1 to 7. According to FIG. 1, a feed line 1 for the shredded tobacco leads via a control element 2 to the inlet area I of a pipe system denoted by 4. A heating medium line 3 is also connected in this area. The pipe system consists (not shown) of a plurality of pipes arranged side by side, the wall of which has protruding recesses 5 and 6 which are rounded inwards. These are offset in the longitudinal direction of the pipe system 4 and form rounded obstacles or baffles. In the outlet area II of the pipe system 4, a funnel-shaped extension 7 is connected, which leads to a drying device, here a drum dryer 8. The drum dryer 8 is rotatably supported in bearings 9 and is rotated by a rotary drive, not shown. An outlet designated by 10 Trim serves to discharge the finished tobacco T. The inlet area of the drum dryer 8 is designated III, its outlet area IV.

The pipe system 4 has a passage width D between 100 and 120 mm and a length L between 2 and 3 m. From lines 1 and 3, the impregnated tobacco is blown into the pipe system at I. The mixture moves at a linear speed V1 in the direction of the outlet area II. In the widening 7, the speed and the temperature of the heating medium are reduced, so that then only a linear speed V2 is present in the drum dryer 8.

The impregnated tobacco is supplied with heat and kinetic energy via the heating medium, as a result of which the impregnating agent contained in its cells suddenly changes to steam and leads to a large increase in volume. The impregnated tobacco has a certain initial moisture content, of which a certain proportion is broken down in the pipe system 4 when the volume is increased, before moisture is then further removed in the drum dryer 8 until the tobacco T in outlet 10 has a predetermined final moisture content .

The process for increasing the volume of tobacco takes place in two separate process steps, the first process step taking place in the pipe system 4 and the second process step in the area of the drum dryer 8. The total process time is between 10 seconds and 5 minutes, the first process step being controlled in this way that it expires in 1/10 of the total length of the proceedings. The characteristic temperature, speed and humidity values are given later using examples in connection with this device. The desired volume increase is aimed at an improvement in the filling capacity of the finished tobacco, the treatment of the tobacco being carried out so gently that there is no reduction in quality and only a minimal drop in tobacco dust or breakage. In the first process depth, the still relatively moist (approx. 60%) tobacco is exposed to intensive turbulence, while in the second process step gentle drying, combined with a low puffing effect, takes place.

2 shows a further embodiment of a device suitable for the method according to the invention. In a container 11, a predetermined amount of cut tobacco T (here cut Maryland ribs) is moistened with an impregnation agent 12 to a certain moisture content. The container 11 is located in the inlet area I of a pipe system 14. A feed line 13 for a heating medium is also connected to the inlet area I. The inner walls of the pipe system 14 are provided with rounded indentations 15, so that there is an undulating cross-sectional configuration in the pipe system 14. A linear velocity V1 is present in the pipe system 14 when the method is carried out. The outlet area II of the pipe system 14 leads to a schematically indicated separator 16, which can be of any type. A discharge line 17 for the heating medium leads away from the separator 16, while a second connecting line 18 leads to a drying device 19, which here is formed by a specially designed multi-belt dryer with twin-wire belts 21 which run over deflection rollers 20. A heating medium 22 circulates transversely to the direction of movement of the belts 21, which are moved at a speed V2. The inlet of the drying device is designated III.

In this device according to FIG. 2, too, the process for increasing the volume of the tobacco takes place in two process steps, with the separator 16 causing an interruption or separation between the two process steps. Again, the total process time is between 10S. and 5 minutes; the first process stage takes place in a maximum of one tenth of the total process time in the pipe system 14.

3 shows a further embodiment of a device for carrying out the method according to the invention. This device consists of a drum dryer 26 with a conical cross-section and a front, narrow dryer section 27 and a section 28 lying further back in the flow direction and increasing in cross section. In the inlet of the drum dryer 26, designated I, is a line 23 with a control element 24 provided for the tobacco, to which a supply line 25 for the heating medium meets, with which the tobacco can be moved through the drum dryer. The surface of the drum dryer 26 has blowing points 30. The drum dryer 26 is also blown transversely to its longitudinal direction with hot, humid air. In section 27, the mixture of heating medium and tobacco flows at a linear speed V1, while at the end II of section 27 up to outlet area III of drum dryer 28 it only has a speed V2 at which tobacco T is discharged from the drum dryer. Here there is a continuous transition between the first process stage and the second process stage, although the tobacco is treated differently in the two process stages.

example 1

A predetermined amount of rolled and cut Virginia Ribs is conventionally grown to an initial moisture content of 60 percent by weight damp. The tobacco impregnated in this way is removed from line 1 in the device according to FIG. 1 by means of the heating medium, which here is an air / water vapor mixture with 80 volume percent water vapor, at a linear speed V1 of 50 m / s through the sealing section 4 emotional. In the inlet area I, the temperature of the heating medium is 205 ° C. With the passage cross section and the length of the pipe system 4 (here 2 meters), the mixture takes an average of 0.3 seconds to the outlet area II. During this period, the volume increase effect expires to approximately 80%. In outlet area II, the moisture content of the tobacco is only 48 percent by weight. The tobacco is then dried in a drum dryer 8 at a temperature of 1200 ° C. to 140 ° C. in 3 minutes to a final moisture content of 12 to 13 percent by weight, the linear speed V2 of the air / water vapor mixture being approximately 5 m / s.

The improvement in filling capacity compared to untreated tobacco, measured using a Borgwaldt densimeter, is already 47% on average when the tobacco is removed from II. A measurement of the improvement in filling capacity at IV showed an average value of 51%, the final moisture content now being only 13%.

A sieve analysis of the tobacco treated according to the method according to the invention showed a proportion increased by 1.0% by weight through a 0.5 mm mesh sieve compared to the untreated tobacco. In a smokers' test, the smoke from the treated tobacco was described as slightly sharper than the smoke from the untreated tobacco.

Example 2

A predetermined amount of rolled and cut Maryland tobacco stems were treated in the apparatus of Figure 2 as follows. First, the tobacco was impregnated in the container 11 with an aqueous solution of sodium dihydrogen phosphate until the initial moisture content was 58 percent by weight and the NaH ₂ PO ₄ content, calculated on the dry weight, was 1.2 percent by weight. The impregnated tobacco was then transported through the pipe system 14 to the separator 16 with the heating medium blown through the line 13, namely a 210 ° C air / water vapor mixture. The tobacco was then finally treated in the drying device 19, the heating medium circulating through the drying device 19 being an air / water vapor mixture with an average of 130 ° C. In the pipe system between inlet I and outlet II, the linear speed V1 averaged 55 m / s. The average length of stay of the tobacco in the pipe system 14 was 0.4 seconds. Between areas II and III, the tobacco still had a moisture content of 42% and already showed an improvement in filling capacity of 58%. In the drying device 19, the heating medium flowed at a linear speed of 6 m / s. The tobacco was in the multi-belt dryer for an average of 2.5 minutes and finally showed a final moisture content of 12.5% with a total filling capacity improvement of 65%.

A smokers' test showed no differences in smoke taste between treated and untreated tobacco.

Example 3

In the device according to FIG. 3, the method according to the invention is carried out with a mixture of cut tobacco leaves and cut tobacco ribs, the tobacco being brought to an initial moisture content of 44% in the usual way beforehand. The impregnated tobacco is then introduced from the line 23 through the heating medium 25 into the drum dryer 26, the cross section of which widens from the beginning to the end to about three times. The average diameter of the tumble dryer is between 1.2 and 1.5 meters.

Two batches of the impregnated tobacco were subjected to the process separately, with different parameters being used to emphasize the positive effect of the process according to the invention.

The first quantity A was introduced into the drum dryer at an air temperature of 180 ° C. in area I at a linear speed of 20 m / s. At III the temperature was still 120 ° C and the linear speed was 7 m / s. There was an improvement in filling capacity of 32%.

The second quantity B was entered with an air temperature at I of 160 ° C. and a linear speed of 6 m / s, the air temperature in region III still being 130 ^° C., while the linear speed was only 2 m / s. This resulted in an improvement in filling capacity of only 8%.

Comparative example

A lot of sliced Virginia tobacco ribs were moistened to an initial moisture content of 60 percent by weight and with an air / water vapor mixture stream that was 250 ° C in the inlet through a smooth, 12 meter long space tube bent several times is transported to a cyclone separator at a linear speed of 42 m / s. The tobacco left the plant after a retention time of 2.5 seconds with a final moisture content of 8 percent by weight. The improvement in filling capacity compared to the untreated tobacco was 49%. The proportion of material that passed through the 0.5 mm sieve compared to untreated tobacco was 7 percent by weight. A smokers test showed that the smoke from the treated tobacco was very sharp with a reduced aroma compared to the smoke from the untreated tobacco.

A further embodiment of a device for carrying out the method according to the invention is indicated in FIG. 4, in which the device part 31 provided for the first method stage is indicated by a dotted line and between an inlet I and an outlet II, which is also the inlet into a drying device 33 , extends. A supply line 1 for the tobacco and a supply line 3 for the heating medium lead to the device part 31. The drying device is formed here by a shaft, the inlet 32 and the outlet is 36. The shaft is designed with a cross section that widens increasingly in the flow direction, for example it has side walls that can be pivoted about pivot bearings 35 in the direction of the double arrows 34. The shaft can either be heated or cooled, as indicated at 37.

5, the method according to the invention can also be carried out in a stationary pneumatic tube 38, which consists of an initial tube section 39 with a constant cross section and an end tube section 40 that gradually widens in cross section. A line 1 for the tobacco and a line 3 for the heating medium lead to the inlet of the pneumatic tube 38 (area I), designated 41. In the longitudinal extension between I and II, the tobacco is moved so quickly by heating medium that approximately 80% of the total increase in volume that can be achieved is achieved there. The final, slight increase in volume of the tobacco and its drying to the desired final moisture content take place between the areas II and III, namely the outlet area 42 of the pneumatic tube 38. The pneumatic tube 38 can - as indicated at 43 - be cooled or heated, or have blowing openings (not shown) through which a cooling or heating medium can be blown. The pneumatic tube 38 is stationary at 44.

6 shows a further embodiment of a device 45 suitable for the method according to the invention in a longitudinal section. 7 is a section in the plane VII-VII in FIG. 6. The device consists of two longitudinally movable sieve belts 46 and 47 which are guided over deflection rollers 48. The sieve belts delimit a tunnel 50 between them, which is closed on both sides of the sieve belts 46, 47 by side seals 49. The height or the clear width of the tunnel 50 is dimensioned such that in an initial area (between I and II) of the device 45 above the tobacco T lying on the lower sieve belt 47, an air space 51 is free, so that the volume increase is not impaired . Immediately behind the sieve belts 46, 47 are inlets 52 and 53 through which a heating medium is blown into the tunnel 50 (by arrows 55 indicated). The openings in the sieve belts 46 and 47 are designated 54. The device 45 is divided in the longitudinal direction into the first section between I and II and a subsequent section between II and III, a process step being carried out in each of these two sections. The tobacco lies on the lower sieve belt 47, for example, at a height between ₂ and 20 cm. Inlets 52 in the first stage of the process produce a hot steam-gas mixture with a temperature of approximately 240 ° C., preferably pulsating, with a relatively high level Blown in speed between 7 and 10 m / s. In the second process stage or in the section between II and III, a steam-gas mixture with a lower steam content and a reduced temperature of 100 to 120 ° C. and a low speed of at most 1 m / s is blown through the device as the heating medium. In the section between I and II, due to the high flow velocity and the high temperature or the higher steam content of the heating medium, the volume increase in the tobacco is completed to approximately 80% of the total possible volume increase. In the second section between II and III, the tobacco, which has been increased in volume, is then gently dried to the desired final moisture content at a lower temperature and a significantly lower speed of the heating medium and with a reduced steam content.

It has proven expedient to work with a heating medium when puffing, the temperature of which is between about 120 and about 300 ° C. In contrast to the method described above, the entire process time (puffing and drying) can be reduced to about 6 seconds and more.

Claims (29)

1. A method for increasing the volume (puffing) of shredded tobacco, in which the tobacco impregnated with an impregnating agent containing at least water to an initial moisture content of at least 35 percent by weight is puffed by means of a gaseous heating medium containing water vapor and then to a final moisture content of 10 to 13 percent by weight, the total process time being at least 10 seconds, characterized in that the process is carried out as a continuous two-step process, in which in the first process step. Puffing conditions the moisture content of the impregnated tobacco based on the initial moisture content is reduced by about 5 to about 6 0%, whereby about at least 80% of the puffing effect which can be achieved during the entire process is achieved, and in which in the second process stage the tobacco until a final moisture content of about 10 to 13 is reached Weight percent is treated at a temperature lower than the puffing temperature. 2. The method according to claim 1, characterized in that in the first process stage, the linear speed of the heating medium is about 7 to about 70 m / s, preferably about 30 to about 60 m / s. 3. The method according to claim 1 or 2, characterized in that the linear speed of the heating medium in the second process stage is reduced by about 10 to about at most 95% compared to the speed in the first process stage. 4. The method according to any one of claims 1 to 3, characterized in that the first process stage is carried out over a maximum of 1/10 of the total process time. 5. The method according to any one of claims 1 to 4, characterized in that the impregnating agent is water. 6. The method according to any one of claims 1 to 5, characterized in that the impregnating agent contains water and / or orthophosphoric acid and / or at least one of its sodium and / or ammonium salts and / or aluminum sulfate. 7. The method according to claim 6, characterized in that the impregnating agent contains orthophosphoric acid and / or its sodium salts and / or ammonium salts in an amount of 0.1 to 2.0 percent by weight, based on the tobacco dry weight. 8. The method according to claim 6, characterized in that the impregnating agent contains about 1 to 3 weight percent aluminum sulfate, based on the tobacco dry weight. 9. The method according to any one of claims 1 to 8, characterized in that the temperature of the heating medium in the first process stage is at least about 130 ° C to at most about 280 ° C. 10. The method according to any one of claims 1 to 9, characterized in that the temperature of the heating medium in the second process stage is reduced by at least about 10% to at most about 50% compared to the temperature in the first process stage. 11. The method according to any one of claims 1 to 10, characterized in that the impregnated tobacco is moved pneumatically and / or mechanically in the first process stage. 12. The method according to any one of claims 1 to 10, characterized in that the tobacco is moved pneumatically and / or mechanically in the second process stage. 13. The method according to any one of claims 1 to 11, characterized in that the tobacco is moved mechanically in the second process stage. 14. The method according to any one of claims 1 to 13, characterized by a continuous transition between the first and the second process stage. 15. The method according to any one of claims 1 to 13, characterized by a discontinuous transition between the first and the second process stage. 16. The method according to any one of claims 1 to 15, characterized in that the total process time is at least 10 seconds to at most about 5 minutes. 17. Device for carrying out the method according to one of claims 1 to 16, characterized by a pipe system consisting of at least one pipe section (4; 14; 31; 39) as the device part intended for the first process stage, its passage width (D) and longitudinal extent (L ) are selected in such a way that, depending on the linear speed (V1) of the heating medium in the first process stage, a residence time of at most 1/10 of the total process time for the moving tobacco (T) can be achieved. 18. The apparatus according to claim 17, characterized in that the inner walls in the pipe system (4; 14) are provided with at least approximately transverse to the direction of movement of the tobacco (T), rounded ridges (5, 6; 15) or baffles. 19. Device according to one of claims 17 or 18, characterized in that the pipe system (4; 14; 31; 39), preferably via a cross-sectional widening (7), is connected to a drying device (8; 19; 33; 40). 20. Device according to one of claims 17 to 19, characterized in that the drying device (33) consists of a widening in cross-section heatable and / or coolable shaft, the cross-sectional expansion is infinitely adjustable. 21. Device according to one of claims 17 to 20, characterized in that the drying device (8) is a drum dryer. 22. Device according to one of claims 17 to 21, characterized in that the drying device (19) is a multi-belt dryer with twin-wire belts (21) and a heating medium circulation (22). 23. Device according to one of claims 17 to 22, characterized in that a separator (16) is arranged between the outlet side (II) of the pipe system (14) and the inlet side (III) of the drying device (19) as a discontinuous transition between the process stages . 24. Device for carrying out the method according to any one of claims 1 to 16, characterized by a drum dryer (26) through which the heating medium and the tobacco flow in the axial direction and with a cross section which increases in the flow direction. 25. The apparatus according to claim 24, characterized in that the drum dryer (26) is acted upon transversely to the axial direction with a uniform flow (29) of hot and humid air and has several injection points for this flow. 26. Device according to one of claims 24 and 25, characterized in that the cross section of the drum dryer from the inlet (I) to the outlet (III) increases to about three times. 27. Device for carrying out the method according to one of claims 1 to 16, characterized by a pair of sieve belts (46, 47) forming a longitudinally laterally closed (49) tunnel (50), and by the tunnel at the top and / or bottom Connected inlets (52, 53) for the heating medium, in the first process stage through the inlets (52) in a first longitudinal section (I - II) through the tobacco (T.) piled up on the lower sieve belt (47) with an air space (51) ) the heating medium can be blown in at a temperature of about 240 ° C and a speed of about 7 - 10 m / s, preferably pulsating, and in the second process stage in a subsequent longitudinal section (II - III) the heating medium with a temperature of approx 100 ° - 120 ° C and a speed of about 1 m / s, preferably continuously, and the heating medium is a gas-water vapor mixture, the vapor content in the second process stage compared to the vapor content i n is lowered in the first stage of the process. 28. Device for carrying out the method according to one of claims 1 to 16, characterized by a stationary pneumatic tube (38) which consists of a first tube section (39) with a substantially constant cross section and a second tube section (40) with an increasing cross section , wherein the pneumatic tube is heatable and / or coolable. 29. A method for increasing the volume (puffing) of shredded tobacco, in which the tobacco impregnated with an impregnating agent containing at least water to an initial moisture content of at least 35% by weight by means of a gaseous heating medium containing water vapor with a temperature between about 12000 and about 300 ° C Temperature puffed and then brought to a final moisture content of about 10 to about 13 percent by weight, the total process time being at least 6 seconds, characterized in that the process is carried out as a continuous two-step process, in which in the first process step under puffing Conditions, the moisture content of the impregnated tobacco is reduced by about 5 to about 60% based on the initial moisture content, with about at least 80% of the puffing effect which can be achieved throughout the process being achieved, and in the tobacco in the second process stage until a final moisture content of about 10 to 13 percent by weight is reached at a temperature lower than the puffing temperature.

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