CA2005332A1 - Method of and apparatus for expanding tobacco - Google Patents
Method of and apparatus for expanding tobaccoInfo
- Publication number
- CA2005332A1 CA2005332A1 CA 2005332 CA2005332A CA2005332A1 CA 2005332 A1 CA2005332 A1 CA 2005332A1 CA 2005332 CA2005332 CA 2005332 CA 2005332 A CA2005332 A CA 2005332A CA 2005332 A1 CA2005332 A1 CA 2005332A1
- Authority
- CA
- Canada
- Prior art keywords
- pressure
- tobacco
- reduction
- range
- thermal processing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
- A24B3/00—Preparing tobacco in the factory
- A24B3/18—Other treatment of leaves, e.g. puffing, crimpling, cleaning
- A24B3/182—Puffing
Landscapes
- Manufacture Of Tobacco Products (AREA)
Abstract
ABSTRACT
In a process for expanding tobacco by impregnation with gas and subsequent thermal processing, tobacco with a moisture content in the range from 20 to 40%-wt (relative to the dry weight of the tobacco) at a temperature at a range from -10 to 0°C, is exposed to a carbon dioxide gas atmosphere at a pressure in the range from 3 to 17 bar. The tobacco is then removed from the high pressure system with controlled reduction of pressure into a thermal processing system.
In a process for expanding tobacco by impregnation with gas and subsequent thermal processing, tobacco with a moisture content in the range from 20 to 40%-wt (relative to the dry weight of the tobacco) at a temperature at a range from -10 to 0°C, is exposed to a carbon dioxide gas atmosphere at a pressure in the range from 3 to 17 bar. The tobacco is then removed from the high pressure system with controlled reduction of pressure into a thermal processing system.
Description
According to DE-OS 29 12 322 (see also US-PS 43 33 483), tobacco having a moisture content of generally in the range between 8 and 22% is brought into contact with gaseous carbon dioxide at a temperature of approximately 80 to 56.2 bar for a sufficiently long period of time and impregnated wit:h the carbon dioxide to form a carbon dioxide/tobacco system, the temperature being so adjusted that essentially all of the carbon dioxide is present in the gaseous phase. Then, this known system, kept at essentially ~;
constant pressure, is cooled to a temperature that is close to the saturation temperature of the carbon dioxide although no ~ ~ -lower than -23C, in order to bring the enthalpy of the carbon dioxide to below approximately 325,640,000 Joule/kg, practically all of the total carbon dioxide being left in the gaseous phase. `~
~hereafter, the pressure of the carbon dioxide/tobacco system is reduced essentially to atmospheric pressure, when the tabacco is then transferred, within approximately 2 to 5 minutes, into an expansion zone and subsequently heated to a temperature in the ;~
range of approximately 100 to 370C, in order to remove the `;; `
carbon dioxide and thereby expand the tobacco. In this known ;
process, during the impregnation of the tobacco, parameters for the application (pressure approximately 18 to 52.6 bar close to ~ -the saturation temperature of the carbon dioxide, although not below -23~C; moisture content of the tobacco 8 to 22%), which ~-~
ensure that all the carbon dioxide is present in the gaseous phase, will apply. In addition, during the subsequent relief of pressure from the tobacco that is impregnated with gaseous carbon ~;
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dioxide and during the subsequent transfer of the tobacco into the expansion zone, some of the carbon dioxide is lost to the atmosphere, since no particular measures to prevent this loss are implemented. Taken all in all, this known process is particularly expensive,since, for example, costly systems are needed because of the high impregnation pressures required by the process, quite apart ~rom the loss of the carbon dioxide and the relatively long residence time.
In addition, DE-PS 34 14 625 describes a process to improve the amenability to bulking of cut tobacco leaves or ribs, in which one operates with a processing gas consisting of nitrogen and/or argon, at temperatures of 50 to 1000 bar, in an autoclave, decompresses this, and then heats it, the charging of the reactor with the tobacco or with the processing gas and/or the decompression being so carried out that the tobacco that is removed and then passed on for subsequent thermal processing has a starting temperature of lower than 0C for the thermal processing. The charging with processing gas and the decompression can be carried out by cascading through several autoclaves such that, in order to build up the pressure of the processing gas in one of the autoclaves by stages, a processing gas that is at a higher pressure than in one of the other autoclaves is used.
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GB-OS 20 44 596 describes a process and an apparatus for expanding tobacco, in which tobacco that contains frozen carbon -~
dioxide is moved into an expansion chamber in which it is expanded by hot gas. The froz~n carbon dioxide is sublimated by this. Gas and expanded tobacco move into a separator, from which the tobacco i5 drawn off through a valve (a rotary disk valve blocking system or metering system).
In the process so described, in which the tobacco is impregnated with carbon dioxide in either liquid or gaseous form, relatively , long impregnation times are required, which applies particularly if the tobacco is in a processing apparatus in fairly large charges, in a stationary state. However, longer residence times require relatively costly, large, pressure-tight systems. ~
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In known processes, in which the tobacco is impregnated with dry ica, the carbon dioxide is used to great excess that is not used for expansion, so that these processes are not particularly economical. In addition, the tobacco's tendency to fracture is increased by this.
GB-OS 21 115 677 describes a process used to expand tobacco in which, in stages, tobacco is a) treated at a moisture content of some 12 to 30%-wt (claim 7) at temperature above the freezing point with, for example, 2~ 3Z
carbon dioxide (claim 2) at a pressure of, for example, 3.4 to 13.8 bar (50 to 200 pisg; claim 3);
b) the tobacco is cooled to a temperature below the freezing point of its moistureî
c) the pressure is reduced and d) the frozen tobacco is heated rapidly to a temperature in the range from approximately 150 to 440C (200 to 600F; claim 5). Since the tobacco thus has to be cooled to below the freezing point of its moisture, this process entails the disadvantage of a considerable consumption of energy.
EP-OS O 328 676 describes a process for expanding tobacco in which one moistens the tobacco (column 5, line 22), exposes it at a temperature in the range from -40 to ~15C (column 7, line 16), to a carbon dioxide gas atmosphere (column 3, line 20), at a pressure in the range from approximately 10 to 50 bar (10 to 50 kg/cm2 G) (column 7, lines 12 to 13) and removes this from the high pressure system during controlled reduction of pressure with the help of pressure locks, into a thermal processing system (column 3, lines 51 to 52). Rotors that incorporate chambers are p_oposed as thesé pressure locks. This prior art is also in need --of improvement.
It is the task of the present invention to improve the prior art described heretofore.
2~ 33X
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According to one first embodiment, the task that underlies the present invention i9 solved by a process to expand tobacco by impregnation with gas and subsequent thermal processing, in which one exposes tobacco having a moisture content in the range from 20 to 40~-wt, relative to the dry weigllt of the tobacco, at a temperature in the range of approximately -10 to 0C, to a carbon dioxide gas atmosphere at a pressure in the range of 3 to 17 bar, and then removes this from the high pressure system during the controlled reduction of pressure, to a thermal processing system.
`' According to the present invention it has been made possible by the optimal selection of the relationships relative to the water solubility of C02 gas in water, to find correlations between three components; moisture content, temperature and pressure such that it has been possible to configure the processing conditions so that they are significantly gentler and more economical.
The quantity of carbon dioxide that is added to the tobacco can -be determined from the solubility curve of C02 in water according to order of magnitude, when it must be borne in mine that, depending on its pH value, the cell sap dissolves somewhat less -C02 gas than pure water.
Furthermore, ac~ording to a second embodiment, the task according to the present invention is solved by a process to expand tobacco ;~
by impregnation with gas and by subsequent thermal processing, in - Z~0533~
.. . .
which one exposes the tobacco with a moisture content in the range of 20 to 40%-wt (based on the dry weight of the tobacco), at a temperature in the range from approximately -10 to ~10C, to a carbon dioxide gas atmosphere with a pressure in the range of 3 to 17 bar, then reduces the pressure in a passage that can be sealed off from the high pressure system, the impregnated tobacco being heated during the pressure reduction phase, and then removes the tobacco into a thermal processing system.
In addition, in a third embodiment, the task according to the present invention has been solved by a process to expand tobacco by impregnation and subsequent thermal treatment in which one impregnates the tobacco at above atmospheric pressure with a gaseous impregnation medium such as air, then reduces the pressure in a passage that can be sealed off from the high pressure system, whereupon one then heats the impregnated tobacco during the pressure-reduction phase and removes it into a thermal processing system.
The process according to the first and second embodiments can be ~;
characterized in that, during impregnation, one permits the tobacco to absorb up to approximately 1%-wt, preferably 0.5 to wt darbon dioxide ~relative to the dry weight of the tobacco).
In addition, the process according to the first and second embodiments can be characterized in that one impregnates tobacco .;';, ;',....
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'. ' " ~.-with a moisture content in the range of 20 to 33%-wt, and in particular 25 to 33~-wt.
;'' The process according to the second embodiment can, in particular, be characterized in that one impregnates the tobacco at a temperature in the range from 10 to +5C or -7 to +5C.
In addition, the process according to the second embodiment can be characterized, in particular, in that one impregnates the tobacao at a temperature in the range from approximately -10 to 0C, and in particular from 10 to -5C.
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The processes according to the first and second embodiments can be characterized, in particular, in that one impregnates the ~`~
tobacco with a pressure in the range from 3 to 10 bar. ~ -'~ " '..~
The process according to the second and third embodiments can be ; ;
characterized, in particular, in that one exposes the impregnated tobacco to microwaves, an electrical alternating field, radiation heat, and contact heat for thermal processing during the pressure-reduction phase. When this is done, during the pressure-reduction phase, one can expose the tobacco to hot gas -such aslhot air or hot carbon dioxide that can encompass the steam, and be at a temperature in the range of 60 to 220C, for example, 150 to 220C. In addition, during the pressure-reduction phase, one can expose the impregnated tobacco to steam 53;~2 that pre~erably is at a temperature in the range from 60 to 2200C, for example, from 150 to 220C.
According to a special embodiment, one can effect the pressure-reduction phase in one stage or in several stages, for example, in two stages. Thus, one can carry oul: the pressure reduction in one stage or in two stages in a time in the range from 0.1 to 5 seconds. or, one can effect the pressure reduction in more than one stage and make provision for each stage to have a residence time in the range of 0.1 to 3 seconds. For example, one can reduce the pressure in two stages, and reduce it in the first stage to a pressure in the range of 2 to 4 bar. Or, in a first `
:, stage, one reduces the pressure from approximately 10 bar to approximately 3.5 bar, and in a second stage reduces it to atmospheric or below atmospheric pressure. If one reduces the pressure in a plurality o~ stages, one aan provide for thermal :
treatment in all the pressure-reduction stages or in only in some of these.
During the particular pressure-reduction stage, one can operate cyclically such that one first raises the pressure to the value ;;;~ `
o~ the tobacco that is to be introduced into the pressure~
reducti~n stage, then introduces the tobacco, and then reduces -the tobacco, removes the tobacco from the pressure-reduction ;
stage, and begins a new cycle. The gas that escapes from the ;; -pressure-reduction stage during the pressure-reduction phase, in . ." " ' ., `, :.. .~'.',:
"''.''~'''~,-'"',',' particular impregnating gas and/or hot gas, ¢an be returned into circulation to the pressure-reduction F;tage.
In the first, second or third embodiment of the process according to the present invention one can carry out the thermal treatment after the pressure-reduction phase at atmospheric pressure or low atmospheric pressure. For example, one can carry out the thermal processing after the pressure-reduction phase with a hot gas, such as hot air, which can encompass the steam, or steam. To this end, one can use hot gas or steam at a temperature of 60 to 300C, preferably in the range from 120 to 300C, in particular 160 to 220~C, and for example, 80 to 220C.
One can use rib cut, reduced leaf tobacco, or leaf tobacco cut as the tobacco.
In addition, according to a fourth embodiment, the task according to the present invention can be solved by a system to produce expanded tobacco, in particular for implementing the three above embodiments o~ the process according to the present invention, which comprises a thermally insulated and/or coolable impregnation system and a subsequent thermal processing system, or includes these.
. ~ ~
The apparatus according to the present invention can ~e characterized in that the impregnation system comprises an ~100~33~ :
autoclave or a plurality o~ autoclaves, which can be arranged in parallel or in series. Thus, two autoclaves can be provided, these being char~ed in alternation with the tobacco that is to be impregnated or emptied alternately of the impregnated tobacco, in alternation.
' :
Each of the autoclaves can incorporate a mixer, for example, a paddle mixer, to loosen the tobacco that is to be impregnated.
Thus, each autoclave can be provided with a rotating drum that incorporates paddles, when the drum and optionally the autoclave .. :: .::
can be arranged so as to be approximately horizontal or inclined.
Alternatively, each autoclave can be configured as a drum and can be arranged either horizontally or inclined.
According to a special embodiment, the impregnation system is ~ ~
connected with a heating system through a pressure-reduction ; ;;
system. It is advantageous if the thermal treatment system is connected directly to the pressure-xeduction system. The . " ~
pressure-reduction system can be in the approximate shape of a pipe. In addition, the pressure-reduction system can be arranged `
approximately vertically.
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For purposes of pressure reduction, the pressure-reductionlsystem -;;
can incorporate at least at its inlet and at its outlet a pressure lock or slide. In addition, the pressure-reduction system can incorporate a lock at the inlet, a lock at the outlet, 11 ,`- ,' ', :'"'-, ' ."' . :~:: .
2~0S33X
and a ~urther lock that is arranged between the two aforementioned locks.
According to a preferred embodiment, the pressure-reduction system can be provided with a generator for microwaves, or for an alternating electrical ~ield, or with at least one inlet for a heated and gaseous medium. When this is done, the inlets for the heated gaseous medium can be arranged on the periphery of the tubular or pipe-like pressure-reduction system. -According to a further special embodiment, the system according to the present invention is characterized by a pneumatic channel as a thermal processing system. This pneumatic channel can be arranged approximately horizontally. In addition, the pneumatic channel can be provided with an inlet for super-heated steam.
An apparatus for carrying out the process according to the present invention will be described in greater detail below with reference to the drawings appended hereto. These drawings show ~-~
tha following~
Figure 1: a diagrammatic representation of a complete system;
Figurel2: a radial ¢ross section through the pretreatment apparatus in figure 1;
2005~32 igure 3: an axial cross section through the connecting pipe between the pressure processing apparatus and the pneumatic channel;
Figure 4: an axial cross section through a further connecting tube.
.
The apparatus shown in figure 1 consists essentially of a pretreatment apparatus A, a pressure-treatment apparatus B, and a pressure-reduction system C, which are connected in series ;;~ ;
through pressure-tight locks.
The pretreatment apparatus A consists of a drum 2 that is of circular cross section, within which a rotor 4 that is fitted ;
with paddles 3 rotates. The sha~t 5 of the rotor 4 passes at one end through the face end of the drum 2 and is driven externally ~ ~ `
by a motor 6 and an intermediate gearing system. The casing of ~;
the drum 2 is double-walled, and a cooling medium can circulate between these walls. An inlet for the tobacco material, configured as a lock 7, extends from above into the drum 2 and rotating doubie-lock elements are arranged within this lock 7. -- ~`- ~. ,`,, A nozzle pipe 8 extends into the drum 2 and this incorporates a series of outlet nozzles through which a moistening medium can be introduced into the drum. In addition, a gas metering line ~
opens out into the drum 2, and a high pressure relief valve 10 is incorporated in this line.
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Whereas the inlet for the tobacco is located at one end of the drum 2, at the opposite end of the drum 2, at the bottom, there is an outlet that is also fitted with a pressure-tight lock 7 that incorporates a double-lock element. This outlet also forms the inlet for the pressure-treatment apparatus B, which is configured so as to be just the same as the pretreatment apparatus A, although with the addition of an additional gas inlet line 13 with a high pressure relief valve 12. The outlet from this pressure-treatment apparatus is formed by a pressure-tight lock 7a that is fitted with a double-lock element; this will be described in greater detail below.
~his lock 7a opens out into a horizontal pneumatic channel 16 into which steam flows through a line 14. The pneumatic channel 16 is connected at the end of the horizontal section to a vertical section into which steam is introduced from a steam feed line 14'. The outlet of tha vertical pipQ section incorporates a cut-off lock 15 that serves to separate the tobacco from the gases flowing in the pneumatic channel 16. The tobacco T is discharged downwards at 17. -~
Figure'2 shows a radial cross section of the double-walled casing of the drum 2 that incorporates a centrally arranged rotor 4 that :
consists of a shaft 5 that is fitted with paddles 3 that extend 2~53~
essentially in a radial direction, and which extend axially to the whole length of the drum 2.
Figure 3 shows the outlet from the pressure-treatment apparatus B that is connected to the pneumatic channel 16, in axial cross ~;
section. The outlet 7a comprises a pipe 21 that incorporates an ~ ~
upper bucket-wheel lock 22a and, at a distance from this, a lower ;
buaket-wheel lock 22b. These bucket-wheel locks are of a known construction and for this reason require no further detailed description herein. It is noted that they operate in synchrony with each other as will be described below, in which connection at no time are both the bucket-wheel locks open simultaneously.
At the lower end of the pipe 21, just above the lower bucket-wheel lock 22b, the pipe 21 incorporates a feed line that surrounds the pipe 21 concentrically and through which gas or steam can be blown into the pipe 21 against the direction of flow, this then producing violent turbulence and pressure within the pipe 21.
-At the upper end of the pipe 21, just beneath the upper bucket-wheel lock 22a, a relief pipe extends to the outside, and this incorpdrates a relief valve 24. Working in conjunction with the gas or steam from the inlet 23, this generates a fluid bed in the ~ -pipe 21.
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`,--, , In addition, the pipe 21 incorporates a pressure sensor P, and this controls the supply of steam or gas and the pressure relief in the pipe 21 a~ a function o~ the position of the bucket wheels of the bucket-wheel locks 22a and 22b by means of a control system 25, this being done in the following manner:
In the first part o~ the cycle, the bucket-wheel lock 22a is open and tobacco is introduced into the pipe 21. When this takes place, the pressure of the medium, consisting of CO2 and steam, within the pipe 21 is brought to approximately 9 bar by means of the valve 26 in the gas inlet 23. In the second part of the cycle, the relief valve 24 opens and with the first bucket-wheel .
lock 22a in the closed position, the pressure in the pipe 21 falls from approximately 9 bar to approximately 3 bar in a period ~ .
of 1 to 3 seconds. In the third part of the cycle, the lower .
bucket-wheel lock 2~b opens and the tobacco drops into the horizontal pneumatia channel 16. Once the lower bucket-wheel lock 22b has been closed again and the upper bucket-wheel lock 22a has been opened, the cycle repeats.
According to another embodiment, the pressure relief of the :
tobacco from the high pressure chamber (A) can be effected in the horizontaI heat treatment-conveyor system (103) in steps, through the vertical connection-expansion pipe (102~ that is connected through the upper lock (101) with the impregnation-high pressure 16 ~ .
i~)0533~ ~ ~
chamber (A~ and through the lower lock (104) with the drying section (103).
The upper lock (101) opens only when thP gas pressure in the connection-expansion pipe (102) is at ,approximately 10 bar, or at approximately the same pressure as in the high pressure apparatus. The lower lock (104) is then closed. The opening conditions for the lower lock are as follows: l bar gas pressure and the upper lock closed. ~
The impregnated tobacco is conveyed through the upper lock into ~ `
the connection-expansion pipe (102) and falls through the lower lock (104) into the drying area (103).
When the connection expansion pipe (102) is empty, both locks are ~ ~
closed and the connection-expansion pipe (102) is connected ~ ;
through the release opening (105) to the accumulator (113) by opening the inlet valve (110). This results in the pressure in the pipe (102) being increased to approximately 10 bar. Then, the inlet valve (110) is closed and the tobacco falls into the pipe as a result of a brief opening of the upper lock (101). Once the upper lock (101) has been closed, the outlet valve (108) is openedland the gas can flow through the outlet openings (106) to the pump (lll). The pump increases the gas pressure and fills the accumulator (113). The reduction of the pressure in the 17 ~`
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connection-expansion pipe (102) is effected continuously by appropriate control of the outlet valve (108).
Shortly before the tobacco reaches the lower nozzle (102), hot CO2 gas at a temperature of 120 to approximately 180~C, is blown through the nozzles (107), which are ori0nted upwards, and into the tobacco. The thermal transfer into the tobacco is greatly improved, and its speed reduced because of the increased relative speeds between the hot gas and the tobacco.
The gas injection phases are controlled by the injection valve ' (109) and are extremely brief.
This gas injection process is repeated several times.
The CO2 gas that is to be injected is taken from the accumulator (113) and heated to the appropriate temperature in the heater (114). -"
Once the gas pressure in the connection-expansion pipe (102) has fallen to 1 ~ar, the lower lock (104) is opened and the tobacco is conveyed out of the connector-expansion pipe. The time between the last injection of hot gas and the opening of the lower lock is so selected that the tobacco has fallen into the lock chamber.
2~ 33~
In order to permit continuous operation within the horizontal heat treatment-conveyor system, the connector-expansion pipe can be supplemented between the outlet lock (104) and the horizontal heat treatment-conveyor system with a tobacco accumulator zone ~`
(not shown herein).
The tobacco can be continually introduced, conveyed and dried within the heat treatment-conveyor system by the steam that flows into this with the help of the venturi nozzles.
Elasticity is imparted to the cooled tobacco by this system and an enhanced expansion effect without any special breakage can be achieved by the controlled pressure release and by the optimized and simultaneous thermal transfer.
' The following test sxamples that can be carried out with this apparatus are explained below.
Example 1 ~ -~
Cut Virginia tobacco cooled to -6C with ice-cold water and -cooled gaseous carbon dioxide, was treated or conveyed, respectively, in the pretreatment apparatus A of the system shown in figure 1, during constant mixing by the rotating paddles 3, to ;~
a moisture content of 35%, at 2 bars, for a period of 4 minutes.
The tobacco moved from this apparatus through the pressure-tight ~
double-lock element and the metering element 7 into the high ;
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pressure processing apparatus B, within which the pressure rose to 10 bar as a result of the additional introduction of cooled gaseous carbon dioxide. The tobacco was then left in the intermediate space formed by the two blocking elements during the removal of the cold carbon dioxide for 3 seconds until an over pressure of 4 bar was reached there.
The tobacco was passed through the second blocking element of the intermediate space into the horizontal pneumatic pipe, within which the tobacco was moved first horizontally within the pipe 16 by the introduction o~ steam at 140C and then vertically, by the introduction of steam from the pipe 14', and thus accelerated twice; the steam and the gaæ were removed in the steam separator 15 and it was carried out through the line 17 in expanded and dry form. This resulted in an increased bulking of the tobacco of 41~ relative to the starting tobacco, as measured at 13% moisture content with a Borgwaldt densimeter.
Example 2 A mixture consisting of cut Burley tobacco was moistened evenly with ice water to a moisture content of 35%. The fixed drum of the pretreatment apparatus A that incorporates a double casing and which is fibted internally with rotating paddles, was filled through the inlet opening arranged in the bottom with gaseous carbon dioxide cooled to -15C at a low flow speed of 2 m/sec until such time as no more air flowed from the tap arranged at Z0~:3S;33~ ~
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the top of the apparatus. The double mantle was filled with a cooling solution and this cooled the casing wall that was in contact with the tobacco to -7C by recirculation.
Then, with the two outlet blocking elements in the closed position and with alternating opening and closing o~ the two `;
inlet blocking elements 7, the tobacco was metered into the pressure treatment apparatus B when the paddles were rotating.
The pressure rose to 10 bar as a result of the additional introduction of additional cooled gaseous carbon dioxide.
After a *our-minute impregnation period, tho pressure treatment ~ ;
apparatus B was moved automatically into an inclined position by means of a hydraulic jacking system. The impregnated tobacco was `- ;
metered continuously into the horizontal pneumatic channel 16 by the alternate opening and closing of the blocking elements 7a ;
arranged one beneath the other in the vertical connecting pipe, where it was subjected by repeated acceleration by steam at 140C
to expansion within a period of less than 1 second.
Super-heated steam was fed through the vertically connected drying pipe line 14' at a higher flow speed than during the horizontal movement of the tobacco and the tobacco left the system through the steam separator 15 with a moisture content of .~3%.
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The treated tobacco exhibited an increase in bulk of 30%, as measured with a Borgwaldt densimeter, at an e~ual moisture content (13~).
Because of the direct transfer of the tobacco from a high pressure environment of 10 bar into an snvironment at atmospheric pressure, there were more breaks or wastage, respectively, and this led to a reduction of the improvement in bulk.
:, . .
Example 3 Cut Virginia leaf tobacco was brought to a moisture content of 30% using iced water in the pretreatment apparatus A.
Within the pressure treatment apparatus B, within which the tobacco had been mixed and which was surrounded with a double casing, the tobacco was maintained at +6C by means of a cooling brine. A pressure of 3 bar was maintained for 5 minutes within the pressure treatment apparatus B, by the introduction of carbon dioxide. The tobacco was then emptied abruptly from the pressure treatment apparatus B into the horizontal thermal pneumatic conveyor channel 16, from which the tobacco was passed with steam at 140C into a vertical conveyor channel. Within this channel, the tobacco was ¢onveyed with a mixture of hot air and ~team into ~
a tower with a double casing in order to be dried, and it then ~ -left this tower with a moisture content of 12~. The bulking factor measured with a Borgwaldt densimeter at 13% tobacco 2 [)fl~53;~
.: , ;
moisture showed an improvement of 8% compared to the untreated .
tobacco. ~.
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Example 4 This was conducted as in Example 1 with the single difference that in the thermal processing phase the tobacco wa~ processed ` : .
with a mixture of steam and carbon dioxide gas at 200C. The :
bulking factor as measured with a Borgwaldt densimeter at 13% ~ .. -tobacco moisture displayed an improvement of 55% as compared to ~
untreated tobacco. .
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~0~33 ,..
Example 5 Virginia tobacco was brought to a moisture content of 25% using ice-cold water. Cold carbon dioxide was introduced into the tobacc~ at a flow speed of approximately 2 m/sec in a high pressure apparatus, from below un-til no more air, but only carbon dioxide, flowed from an outlet valve located in the upper part of the apparatus. The apparatus, which incorporated a tobacco inlet in its upper part and outlet points in its lower part, each with faed and discharge channels, was then maintained at a relatively constant pressure in that the further introduction of CO2 gas was effected with the blocking elements closed, for all practical purposes. This was made possible in that in each of the vertical feed and discharge channels there were two metering and blocking elements, spaced apart, which were synchronized such that when one was in the closed state, the other was in the open state, this taking place in alternation. The pressure was adjusted to 9 bar. ~he tobacco temperature was brought to -6C by pre-cooling and by the double casing that surrounded the pressure apparatus, within which a cooling brine was recirculated. The tobacco was -;
moved continually forwards within the pressure apparatus by means of a mixing and conveyor system.
After an impregnation period of 4 minutes, the tobacco left the pressur~ apparatus through the discharge-blocking and metering elements such that the reduction in pressure in the vertical ;
discharge channel was effected in the intervening space by means : ' ' ;: -:
24 ;~
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Z~ 33 of a valve when it was reduced to 4 ba:r in a period of 3 seconds; ~:
the tobacco then fell from this area within a horizontal heat processing channel that was hermetically connected directly to the connection channel, where it was carried along by a current ~.
of steam at a temperature of 140C. According to the solubility curve of the C2 gas in water, approximately 0.7 to 0.8%-wt of CO2 gas was added to the tobacco under the above-described impregnation conditions. Within the heat processing channel, the tobacco was conveyed pneumatically within a horizontal pipe that ::
opened out into a vertical pipe, where it was dried to a 15% -::
water content by hot gas at a temperature of 160C. Measurement ;
of the bulking factor for the treated and the untreated tobacco ..
was carried out at 13~ moisture content, using a Borgwaldt densimeter. ;
The bulking factor improvement compared to the control sample amounted to 41%. :
Example_6 A mixture of Burley and Virginia tobacco was moistened to a .-moisture content of 32%. Cooled C2 gas (-15C) was passed through the tobacco within the double-walled high pressure apparatus until the pressure rose to 9,5 bar. Within the double wall there was a cooling brine, so that the tobacco was at a temperature of -9C during an impregnation period of 4 minutes, during constant mixing. According to the solubility curve for Z~ i3~
C02 gas in water, the tobacco had a C02 content of approximately 0.8%-wt. Next, the cold tobacco was metered for a period o~ 2 seconds through a vertical connector tube within the pressure range of 3 bar from which it was subjected to steam and hot gas processing by the exclusion of the outside atmosphere. After expansion and drying in the pneumatic heat treatment system at a temperature of 200C, the tobacco displayed a final moisture content of 10%. After adjustment of the tobacco moisture to 13%, the bulking factor was determined using a Borgwaldt densimeter.
Compared to the untreated tobacco at the same moisture content, the bulking factor improvement was 59%.
Example 7 A mixture of Burley and Virginia cut tobacco was moistened to a 23% moisture content. ~his example was conducted as in Example 6, with the difference that the pressure used for impregnation ``
amounted to only 7 bar instead 9.5 bar. After cooling, the temperature of the tobacco was -5C. The drying temperature was 170C and the moisture content of the tobacco amounted to 13%. ;~;
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The improvement of the bulking factor at a 13% tobacco moisture content amounted to 38% compared to the control sample, at the ~;
same moisture content. ~ `
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~ :.
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21)~1~33~
:
:
Example 8 The ame tobacco was processed analogously to that in Example 7.
The tobacco moisture was 25~, the impregnation pressure 7 bar, the temperature of the tobacco during impregnation was ~5C, the drying temperature, 160C, and the final moisture content of the ;
tobacco 13%. The improvement in the bulking factor at 13%
moisture content was 30% compared to the control sample at an egual moisture content.
: . .
constant pressure, is cooled to a temperature that is close to the saturation temperature of the carbon dioxide although no ~ ~ -lower than -23C, in order to bring the enthalpy of the carbon dioxide to below approximately 325,640,000 Joule/kg, practically all of the total carbon dioxide being left in the gaseous phase. `~
~hereafter, the pressure of the carbon dioxide/tobacco system is reduced essentially to atmospheric pressure, when the tabacco is then transferred, within approximately 2 to 5 minutes, into an expansion zone and subsequently heated to a temperature in the ;~
range of approximately 100 to 370C, in order to remove the `;; `
carbon dioxide and thereby expand the tobacco. In this known ;
process, during the impregnation of the tobacco, parameters for the application (pressure approximately 18 to 52.6 bar close to ~ -the saturation temperature of the carbon dioxide, although not below -23~C; moisture content of the tobacco 8 to 22%), which ~-~
ensure that all the carbon dioxide is present in the gaseous phase, will apply. In addition, during the subsequent relief of pressure from the tobacco that is impregnated with gaseous carbon ~;
-:-, ,`.: `;: ,~ . ."' ,." ' '' ''' '' ", i. ~: ' ' "; .';
~ 201)533~
.
dioxide and during the subsequent transfer of the tobacco into the expansion zone, some of the carbon dioxide is lost to the atmosphere, since no particular measures to prevent this loss are implemented. Taken all in all, this known process is particularly expensive,since, for example, costly systems are needed because of the high impregnation pressures required by the process, quite apart ~rom the loss of the carbon dioxide and the relatively long residence time.
In addition, DE-PS 34 14 625 describes a process to improve the amenability to bulking of cut tobacco leaves or ribs, in which one operates with a processing gas consisting of nitrogen and/or argon, at temperatures of 50 to 1000 bar, in an autoclave, decompresses this, and then heats it, the charging of the reactor with the tobacco or with the processing gas and/or the decompression being so carried out that the tobacco that is removed and then passed on for subsequent thermal processing has a starting temperature of lower than 0C for the thermal processing. The charging with processing gas and the decompression can be carried out by cascading through several autoclaves such that, in order to build up the pressure of the processing gas in one of the autoclaves by stages, a processing gas that is at a higher pressure than in one of the other autoclaves is used.
X~ 33~ ~
GB-OS 20 44 596 describes a process and an apparatus for expanding tobacco, in which tobacco that contains frozen carbon -~
dioxide is moved into an expansion chamber in which it is expanded by hot gas. The froz~n carbon dioxide is sublimated by this. Gas and expanded tobacco move into a separator, from which the tobacco i5 drawn off through a valve (a rotary disk valve blocking system or metering system).
In the process so described, in which the tobacco is impregnated with carbon dioxide in either liquid or gaseous form, relatively , long impregnation times are required, which applies particularly if the tobacco is in a processing apparatus in fairly large charges, in a stationary state. However, longer residence times require relatively costly, large, pressure-tight systems. ~
":
In known processes, in which the tobacco is impregnated with dry ica, the carbon dioxide is used to great excess that is not used for expansion, so that these processes are not particularly economical. In addition, the tobacco's tendency to fracture is increased by this.
GB-OS 21 115 677 describes a process used to expand tobacco in which, in stages, tobacco is a) treated at a moisture content of some 12 to 30%-wt (claim 7) at temperature above the freezing point with, for example, 2~ 3Z
carbon dioxide (claim 2) at a pressure of, for example, 3.4 to 13.8 bar (50 to 200 pisg; claim 3);
b) the tobacco is cooled to a temperature below the freezing point of its moistureî
c) the pressure is reduced and d) the frozen tobacco is heated rapidly to a temperature in the range from approximately 150 to 440C (200 to 600F; claim 5). Since the tobacco thus has to be cooled to below the freezing point of its moisture, this process entails the disadvantage of a considerable consumption of energy.
EP-OS O 328 676 describes a process for expanding tobacco in which one moistens the tobacco (column 5, line 22), exposes it at a temperature in the range from -40 to ~15C (column 7, line 16), to a carbon dioxide gas atmosphere (column 3, line 20), at a pressure in the range from approximately 10 to 50 bar (10 to 50 kg/cm2 G) (column 7, lines 12 to 13) and removes this from the high pressure system during controlled reduction of pressure with the help of pressure locks, into a thermal processing system (column 3, lines 51 to 52). Rotors that incorporate chambers are p_oposed as thesé pressure locks. This prior art is also in need --of improvement.
It is the task of the present invention to improve the prior art described heretofore.
2~ 33X
,.
According to one first embodiment, the task that underlies the present invention i9 solved by a process to expand tobacco by impregnation with gas and subsequent thermal processing, in which one exposes tobacco having a moisture content in the range from 20 to 40~-wt, relative to the dry weigllt of the tobacco, at a temperature in the range of approximately -10 to 0C, to a carbon dioxide gas atmosphere at a pressure in the range of 3 to 17 bar, and then removes this from the high pressure system during the controlled reduction of pressure, to a thermal processing system.
`' According to the present invention it has been made possible by the optimal selection of the relationships relative to the water solubility of C02 gas in water, to find correlations between three components; moisture content, temperature and pressure such that it has been possible to configure the processing conditions so that they are significantly gentler and more economical.
The quantity of carbon dioxide that is added to the tobacco can -be determined from the solubility curve of C02 in water according to order of magnitude, when it must be borne in mine that, depending on its pH value, the cell sap dissolves somewhat less -C02 gas than pure water.
Furthermore, ac~ording to a second embodiment, the task according to the present invention is solved by a process to expand tobacco ;~
by impregnation with gas and by subsequent thermal processing, in - Z~0533~
.. . .
which one exposes the tobacco with a moisture content in the range of 20 to 40%-wt (based on the dry weight of the tobacco), at a temperature in the range from approximately -10 to ~10C, to a carbon dioxide gas atmosphere with a pressure in the range of 3 to 17 bar, then reduces the pressure in a passage that can be sealed off from the high pressure system, the impregnated tobacco being heated during the pressure reduction phase, and then removes the tobacco into a thermal processing system.
In addition, in a third embodiment, the task according to the present invention has been solved by a process to expand tobacco by impregnation and subsequent thermal treatment in which one impregnates the tobacco at above atmospheric pressure with a gaseous impregnation medium such as air, then reduces the pressure in a passage that can be sealed off from the high pressure system, whereupon one then heats the impregnated tobacco during the pressure-reduction phase and removes it into a thermal processing system.
The process according to the first and second embodiments can be ~;
characterized in that, during impregnation, one permits the tobacco to absorb up to approximately 1%-wt, preferably 0.5 to wt darbon dioxide ~relative to the dry weight of the tobacco).
In addition, the process according to the first and second embodiments can be characterized in that one impregnates tobacco .;';, ;',....
''; ' ;;''~:
'. ' " ~.-with a moisture content in the range of 20 to 33%-wt, and in particular 25 to 33~-wt.
;'' The process according to the second embodiment can, in particular, be characterized in that one impregnates the tobacco at a temperature in the range from 10 to +5C or -7 to +5C.
In addition, the process according to the second embodiment can be characterized, in particular, in that one impregnates the tobacao at a temperature in the range from approximately -10 to 0C, and in particular from 10 to -5C.
' . ;~ ~ " `.''''"
The processes according to the first and second embodiments can be characterized, in particular, in that one impregnates the ~`~
tobacco with a pressure in the range from 3 to 10 bar. ~ -'~ " '..~
The process according to the second and third embodiments can be ; ;
characterized, in particular, in that one exposes the impregnated tobacco to microwaves, an electrical alternating field, radiation heat, and contact heat for thermal processing during the pressure-reduction phase. When this is done, during the pressure-reduction phase, one can expose the tobacco to hot gas -such aslhot air or hot carbon dioxide that can encompass the steam, and be at a temperature in the range of 60 to 220C, for example, 150 to 220C. In addition, during the pressure-reduction phase, one can expose the impregnated tobacco to steam 53;~2 that pre~erably is at a temperature in the range from 60 to 2200C, for example, from 150 to 220C.
According to a special embodiment, one can effect the pressure-reduction phase in one stage or in several stages, for example, in two stages. Thus, one can carry oul: the pressure reduction in one stage or in two stages in a time in the range from 0.1 to 5 seconds. or, one can effect the pressure reduction in more than one stage and make provision for each stage to have a residence time in the range of 0.1 to 3 seconds. For example, one can reduce the pressure in two stages, and reduce it in the first stage to a pressure in the range of 2 to 4 bar. Or, in a first `
:, stage, one reduces the pressure from approximately 10 bar to approximately 3.5 bar, and in a second stage reduces it to atmospheric or below atmospheric pressure. If one reduces the pressure in a plurality o~ stages, one aan provide for thermal :
treatment in all the pressure-reduction stages or in only in some of these.
During the particular pressure-reduction stage, one can operate cyclically such that one first raises the pressure to the value ;;;~ `
o~ the tobacco that is to be introduced into the pressure~
reducti~n stage, then introduces the tobacco, and then reduces -the tobacco, removes the tobacco from the pressure-reduction ;
stage, and begins a new cycle. The gas that escapes from the ;; -pressure-reduction stage during the pressure-reduction phase, in . ." " ' ., `, :.. .~'.',:
"''.''~'''~,-'"',',' particular impregnating gas and/or hot gas, ¢an be returned into circulation to the pressure-reduction F;tage.
In the first, second or third embodiment of the process according to the present invention one can carry out the thermal treatment after the pressure-reduction phase at atmospheric pressure or low atmospheric pressure. For example, one can carry out the thermal processing after the pressure-reduction phase with a hot gas, such as hot air, which can encompass the steam, or steam. To this end, one can use hot gas or steam at a temperature of 60 to 300C, preferably in the range from 120 to 300C, in particular 160 to 220~C, and for example, 80 to 220C.
One can use rib cut, reduced leaf tobacco, or leaf tobacco cut as the tobacco.
In addition, according to a fourth embodiment, the task according to the present invention can be solved by a system to produce expanded tobacco, in particular for implementing the three above embodiments o~ the process according to the present invention, which comprises a thermally insulated and/or coolable impregnation system and a subsequent thermal processing system, or includes these.
. ~ ~
The apparatus according to the present invention can ~e characterized in that the impregnation system comprises an ~100~33~ :
autoclave or a plurality o~ autoclaves, which can be arranged in parallel or in series. Thus, two autoclaves can be provided, these being char~ed in alternation with the tobacco that is to be impregnated or emptied alternately of the impregnated tobacco, in alternation.
' :
Each of the autoclaves can incorporate a mixer, for example, a paddle mixer, to loosen the tobacco that is to be impregnated.
Thus, each autoclave can be provided with a rotating drum that incorporates paddles, when the drum and optionally the autoclave .. :: .::
can be arranged so as to be approximately horizontal or inclined.
Alternatively, each autoclave can be configured as a drum and can be arranged either horizontally or inclined.
According to a special embodiment, the impregnation system is ~ ~
connected with a heating system through a pressure-reduction ; ;;
system. It is advantageous if the thermal treatment system is connected directly to the pressure-xeduction system. The . " ~
pressure-reduction system can be in the approximate shape of a pipe. In addition, the pressure-reduction system can be arranged `
approximately vertically.
.: . . - :: ..
~; :.;~ .~.
For purposes of pressure reduction, the pressure-reductionlsystem -;;
can incorporate at least at its inlet and at its outlet a pressure lock or slide. In addition, the pressure-reduction system can incorporate a lock at the inlet, a lock at the outlet, 11 ,`- ,' ', :'"'-, ' ."' . :~:: .
2~0S33X
and a ~urther lock that is arranged between the two aforementioned locks.
According to a preferred embodiment, the pressure-reduction system can be provided with a generator for microwaves, or for an alternating electrical ~ield, or with at least one inlet for a heated and gaseous medium. When this is done, the inlets for the heated gaseous medium can be arranged on the periphery of the tubular or pipe-like pressure-reduction system. -According to a further special embodiment, the system according to the present invention is characterized by a pneumatic channel as a thermal processing system. This pneumatic channel can be arranged approximately horizontally. In addition, the pneumatic channel can be provided with an inlet for super-heated steam.
An apparatus for carrying out the process according to the present invention will be described in greater detail below with reference to the drawings appended hereto. These drawings show ~-~
tha following~
Figure 1: a diagrammatic representation of a complete system;
Figurel2: a radial ¢ross section through the pretreatment apparatus in figure 1;
2005~32 igure 3: an axial cross section through the connecting pipe between the pressure processing apparatus and the pneumatic channel;
Figure 4: an axial cross section through a further connecting tube.
.
The apparatus shown in figure 1 consists essentially of a pretreatment apparatus A, a pressure-treatment apparatus B, and a pressure-reduction system C, which are connected in series ;;~ ;
through pressure-tight locks.
The pretreatment apparatus A consists of a drum 2 that is of circular cross section, within which a rotor 4 that is fitted ;
with paddles 3 rotates. The sha~t 5 of the rotor 4 passes at one end through the face end of the drum 2 and is driven externally ~ ~ `
by a motor 6 and an intermediate gearing system. The casing of ~;
the drum 2 is double-walled, and a cooling medium can circulate between these walls. An inlet for the tobacco material, configured as a lock 7, extends from above into the drum 2 and rotating doubie-lock elements are arranged within this lock 7. -- ~`- ~. ,`,, A nozzle pipe 8 extends into the drum 2 and this incorporates a series of outlet nozzles through which a moistening medium can be introduced into the drum. In addition, a gas metering line ~
opens out into the drum 2, and a high pressure relief valve 10 is incorporated in this line.
~5;~3~
- :
Whereas the inlet for the tobacco is located at one end of the drum 2, at the opposite end of the drum 2, at the bottom, there is an outlet that is also fitted with a pressure-tight lock 7 that incorporates a double-lock element. This outlet also forms the inlet for the pressure-treatment apparatus B, which is configured so as to be just the same as the pretreatment apparatus A, although with the addition of an additional gas inlet line 13 with a high pressure relief valve 12. The outlet from this pressure-treatment apparatus is formed by a pressure-tight lock 7a that is fitted with a double-lock element; this will be described in greater detail below.
~his lock 7a opens out into a horizontal pneumatic channel 16 into which steam flows through a line 14. The pneumatic channel 16 is connected at the end of the horizontal section to a vertical section into which steam is introduced from a steam feed line 14'. The outlet of tha vertical pipQ section incorporates a cut-off lock 15 that serves to separate the tobacco from the gases flowing in the pneumatic channel 16. The tobacco T is discharged downwards at 17. -~
Figure'2 shows a radial cross section of the double-walled casing of the drum 2 that incorporates a centrally arranged rotor 4 that :
consists of a shaft 5 that is fitted with paddles 3 that extend 2~53~
essentially in a radial direction, and which extend axially to the whole length of the drum 2.
Figure 3 shows the outlet from the pressure-treatment apparatus B that is connected to the pneumatic channel 16, in axial cross ~;
section. The outlet 7a comprises a pipe 21 that incorporates an ~ ~
upper bucket-wheel lock 22a and, at a distance from this, a lower ;
buaket-wheel lock 22b. These bucket-wheel locks are of a known construction and for this reason require no further detailed description herein. It is noted that they operate in synchrony with each other as will be described below, in which connection at no time are both the bucket-wheel locks open simultaneously.
At the lower end of the pipe 21, just above the lower bucket-wheel lock 22b, the pipe 21 incorporates a feed line that surrounds the pipe 21 concentrically and through which gas or steam can be blown into the pipe 21 against the direction of flow, this then producing violent turbulence and pressure within the pipe 21.
-At the upper end of the pipe 21, just beneath the upper bucket-wheel lock 22a, a relief pipe extends to the outside, and this incorpdrates a relief valve 24. Working in conjunction with the gas or steam from the inlet 23, this generates a fluid bed in the ~ -pipe 21.
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Z(:~5~3~
`,--, , In addition, the pipe 21 incorporates a pressure sensor P, and this controls the supply of steam or gas and the pressure relief in the pipe 21 a~ a function o~ the position of the bucket wheels of the bucket-wheel locks 22a and 22b by means of a control system 25, this being done in the following manner:
In the first part o~ the cycle, the bucket-wheel lock 22a is open and tobacco is introduced into the pipe 21. When this takes place, the pressure of the medium, consisting of CO2 and steam, within the pipe 21 is brought to approximately 9 bar by means of the valve 26 in the gas inlet 23. In the second part of the cycle, the relief valve 24 opens and with the first bucket-wheel .
lock 22a in the closed position, the pressure in the pipe 21 falls from approximately 9 bar to approximately 3 bar in a period ~ .
of 1 to 3 seconds. In the third part of the cycle, the lower .
bucket-wheel lock 2~b opens and the tobacco drops into the horizontal pneumatia channel 16. Once the lower bucket-wheel lock 22b has been closed again and the upper bucket-wheel lock 22a has been opened, the cycle repeats.
According to another embodiment, the pressure relief of the :
tobacco from the high pressure chamber (A) can be effected in the horizontaI heat treatment-conveyor system (103) in steps, through the vertical connection-expansion pipe (102~ that is connected through the upper lock (101) with the impregnation-high pressure 16 ~ .
i~)0533~ ~ ~
chamber (A~ and through the lower lock (104) with the drying section (103).
The upper lock (101) opens only when thP gas pressure in the connection-expansion pipe (102) is at ,approximately 10 bar, or at approximately the same pressure as in the high pressure apparatus. The lower lock (104) is then closed. The opening conditions for the lower lock are as follows: l bar gas pressure and the upper lock closed. ~
The impregnated tobacco is conveyed through the upper lock into ~ `
the connection-expansion pipe (102) and falls through the lower lock (104) into the drying area (103).
When the connection expansion pipe (102) is empty, both locks are ~ ~
closed and the connection-expansion pipe (102) is connected ~ ;
through the release opening (105) to the accumulator (113) by opening the inlet valve (110). This results in the pressure in the pipe (102) being increased to approximately 10 bar. Then, the inlet valve (110) is closed and the tobacco falls into the pipe as a result of a brief opening of the upper lock (101). Once the upper lock (101) has been closed, the outlet valve (108) is openedland the gas can flow through the outlet openings (106) to the pump (lll). The pump increases the gas pressure and fills the accumulator (113). The reduction of the pressure in the 17 ~`
.: . .
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,. .. . - , ,; , , :: , - - , ~ :::: - -~ :
~I~OS33Z
connection-expansion pipe (102) is effected continuously by appropriate control of the outlet valve (108).
Shortly before the tobacco reaches the lower nozzle (102), hot CO2 gas at a temperature of 120 to approximately 180~C, is blown through the nozzles (107), which are ori0nted upwards, and into the tobacco. The thermal transfer into the tobacco is greatly improved, and its speed reduced because of the increased relative speeds between the hot gas and the tobacco.
The gas injection phases are controlled by the injection valve ' (109) and are extremely brief.
This gas injection process is repeated several times.
The CO2 gas that is to be injected is taken from the accumulator (113) and heated to the appropriate temperature in the heater (114). -"
Once the gas pressure in the connection-expansion pipe (102) has fallen to 1 ~ar, the lower lock (104) is opened and the tobacco is conveyed out of the connector-expansion pipe. The time between the last injection of hot gas and the opening of the lower lock is so selected that the tobacco has fallen into the lock chamber.
2~ 33~
In order to permit continuous operation within the horizontal heat treatment-conveyor system, the connector-expansion pipe can be supplemented between the outlet lock (104) and the horizontal heat treatment-conveyor system with a tobacco accumulator zone ~`
(not shown herein).
The tobacco can be continually introduced, conveyed and dried within the heat treatment-conveyor system by the steam that flows into this with the help of the venturi nozzles.
Elasticity is imparted to the cooled tobacco by this system and an enhanced expansion effect without any special breakage can be achieved by the controlled pressure release and by the optimized and simultaneous thermal transfer.
' The following test sxamples that can be carried out with this apparatus are explained below.
Example 1 ~ -~
Cut Virginia tobacco cooled to -6C with ice-cold water and -cooled gaseous carbon dioxide, was treated or conveyed, respectively, in the pretreatment apparatus A of the system shown in figure 1, during constant mixing by the rotating paddles 3, to ;~
a moisture content of 35%, at 2 bars, for a period of 4 minutes.
The tobacco moved from this apparatus through the pressure-tight ~
double-lock element and the metering element 7 into the high ;
19 '.` , :`
.......... - .. ::
: :: ` 20~)~33Z
pressure processing apparatus B, within which the pressure rose to 10 bar as a result of the additional introduction of cooled gaseous carbon dioxide. The tobacco was then left in the intermediate space formed by the two blocking elements during the removal of the cold carbon dioxide for 3 seconds until an over pressure of 4 bar was reached there.
The tobacco was passed through the second blocking element of the intermediate space into the horizontal pneumatic pipe, within which the tobacco was moved first horizontally within the pipe 16 by the introduction o~ steam at 140C and then vertically, by the introduction of steam from the pipe 14', and thus accelerated twice; the steam and the gaæ were removed in the steam separator 15 and it was carried out through the line 17 in expanded and dry form. This resulted in an increased bulking of the tobacco of 41~ relative to the starting tobacco, as measured at 13% moisture content with a Borgwaldt densimeter.
Example 2 A mixture consisting of cut Burley tobacco was moistened evenly with ice water to a moisture content of 35%. The fixed drum of the pretreatment apparatus A that incorporates a double casing and which is fibted internally with rotating paddles, was filled through the inlet opening arranged in the bottom with gaseous carbon dioxide cooled to -15C at a low flow speed of 2 m/sec until such time as no more air flowed from the tap arranged at Z0~:3S;33~ ~
.` , :
the top of the apparatus. The double mantle was filled with a cooling solution and this cooled the casing wall that was in contact with the tobacco to -7C by recirculation.
Then, with the two outlet blocking elements in the closed position and with alternating opening and closing o~ the two `;
inlet blocking elements 7, the tobacco was metered into the pressure treatment apparatus B when the paddles were rotating.
The pressure rose to 10 bar as a result of the additional introduction of additional cooled gaseous carbon dioxide.
After a *our-minute impregnation period, tho pressure treatment ~ ;
apparatus B was moved automatically into an inclined position by means of a hydraulic jacking system. The impregnated tobacco was `- ;
metered continuously into the horizontal pneumatic channel 16 by the alternate opening and closing of the blocking elements 7a ;
arranged one beneath the other in the vertical connecting pipe, where it was subjected by repeated acceleration by steam at 140C
to expansion within a period of less than 1 second.
Super-heated steam was fed through the vertically connected drying pipe line 14' at a higher flow speed than during the horizontal movement of the tobacco and the tobacco left the system through the steam separator 15 with a moisture content of .~3%.
''': ': . ' ~: :.,.
-- ZO()S33Z
The treated tobacco exhibited an increase in bulk of 30%, as measured with a Borgwaldt densimeter, at an e~ual moisture content (13~).
Because of the direct transfer of the tobacco from a high pressure environment of 10 bar into an snvironment at atmospheric pressure, there were more breaks or wastage, respectively, and this led to a reduction of the improvement in bulk.
:, . .
Example 3 Cut Virginia leaf tobacco was brought to a moisture content of 30% using iced water in the pretreatment apparatus A.
Within the pressure treatment apparatus B, within which the tobacco had been mixed and which was surrounded with a double casing, the tobacco was maintained at +6C by means of a cooling brine. A pressure of 3 bar was maintained for 5 minutes within the pressure treatment apparatus B, by the introduction of carbon dioxide. The tobacco was then emptied abruptly from the pressure treatment apparatus B into the horizontal thermal pneumatic conveyor channel 16, from which the tobacco was passed with steam at 140C into a vertical conveyor channel. Within this channel, the tobacco was ¢onveyed with a mixture of hot air and ~team into ~
a tower with a double casing in order to be dried, and it then ~ -left this tower with a moisture content of 12~. The bulking factor measured with a Borgwaldt densimeter at 13% tobacco 2 [)fl~53;~
.: , ;
moisture showed an improvement of 8% compared to the untreated .
tobacco. ~.
,".....
Example 4 This was conducted as in Example 1 with the single difference that in the thermal processing phase the tobacco wa~ processed ` : .
with a mixture of steam and carbon dioxide gas at 200C. The :
bulking factor as measured with a Borgwaldt densimeter at 13% ~ .. -tobacco moisture displayed an improvement of 55% as compared to ~
untreated tobacco. .
''' ,':'''~
~0~33 ,..
Example 5 Virginia tobacco was brought to a moisture content of 25% using ice-cold water. Cold carbon dioxide was introduced into the tobacc~ at a flow speed of approximately 2 m/sec in a high pressure apparatus, from below un-til no more air, but only carbon dioxide, flowed from an outlet valve located in the upper part of the apparatus. The apparatus, which incorporated a tobacco inlet in its upper part and outlet points in its lower part, each with faed and discharge channels, was then maintained at a relatively constant pressure in that the further introduction of CO2 gas was effected with the blocking elements closed, for all practical purposes. This was made possible in that in each of the vertical feed and discharge channels there were two metering and blocking elements, spaced apart, which were synchronized such that when one was in the closed state, the other was in the open state, this taking place in alternation. The pressure was adjusted to 9 bar. ~he tobacco temperature was brought to -6C by pre-cooling and by the double casing that surrounded the pressure apparatus, within which a cooling brine was recirculated. The tobacco was -;
moved continually forwards within the pressure apparatus by means of a mixing and conveyor system.
After an impregnation period of 4 minutes, the tobacco left the pressur~ apparatus through the discharge-blocking and metering elements such that the reduction in pressure in the vertical ;
discharge channel was effected in the intervening space by means : ' ' ;: -:
24 ;~
: . - :--."',' ~-'~'',''.,.'"
Z~ 33 of a valve when it was reduced to 4 ba:r in a period of 3 seconds; ~:
the tobacco then fell from this area within a horizontal heat processing channel that was hermetically connected directly to the connection channel, where it was carried along by a current ~.
of steam at a temperature of 140C. According to the solubility curve of the C2 gas in water, approximately 0.7 to 0.8%-wt of CO2 gas was added to the tobacco under the above-described impregnation conditions. Within the heat processing channel, the tobacco was conveyed pneumatically within a horizontal pipe that ::
opened out into a vertical pipe, where it was dried to a 15% -::
water content by hot gas at a temperature of 160C. Measurement ;
of the bulking factor for the treated and the untreated tobacco ..
was carried out at 13~ moisture content, using a Borgwaldt densimeter. ;
The bulking factor improvement compared to the control sample amounted to 41%. :
Example_6 A mixture of Burley and Virginia tobacco was moistened to a .-moisture content of 32%. Cooled C2 gas (-15C) was passed through the tobacco within the double-walled high pressure apparatus until the pressure rose to 9,5 bar. Within the double wall there was a cooling brine, so that the tobacco was at a temperature of -9C during an impregnation period of 4 minutes, during constant mixing. According to the solubility curve for Z~ i3~
C02 gas in water, the tobacco had a C02 content of approximately 0.8%-wt. Next, the cold tobacco was metered for a period o~ 2 seconds through a vertical connector tube within the pressure range of 3 bar from which it was subjected to steam and hot gas processing by the exclusion of the outside atmosphere. After expansion and drying in the pneumatic heat treatment system at a temperature of 200C, the tobacco displayed a final moisture content of 10%. After adjustment of the tobacco moisture to 13%, the bulking factor was determined using a Borgwaldt densimeter.
Compared to the untreated tobacco at the same moisture content, the bulking factor improvement was 59%.
Example 7 A mixture of Burley and Virginia cut tobacco was moistened to a 23% moisture content. ~his example was conducted as in Example 6, with the difference that the pressure used for impregnation ``
amounted to only 7 bar instead 9.5 bar. After cooling, the temperature of the tobacco was -5C. The drying temperature was 170C and the moisture content of the tobacco amounted to 13%. ;~;
. ': ~,'...
The improvement of the bulking factor at a 13% tobacco moisture content amounted to 38% compared to the control sample, at the ~;
same moisture content. ~ `
:::: .. :-.
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~ :.
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26 ~; ~
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21)~1~33~
:
:
Example 8 The ame tobacco was processed analogously to that in Example 7.
The tobacco moisture was 25~, the impregnation pressure 7 bar, the temperature of the tobacco during impregnation was ~5C, the drying temperature, 160C, and the final moisture content of the ;
tobacco 13%. The improvement in the bulking factor at 13%
moisture content was 30% compared to the control sample at an egual moisture content.
: . .
Claims (41)
1. A process for expanding tobacco by impregnation with gas and subsequent thermal processing, in which one exposes tobacco with a moisture content in the range from 20 to 40%-wt (relative to the dry weight of the tobacco) at a temperature at a range from -10 to 0°C, to a carbon dioxide gas atmosphere at a pressure in the range from 3 to 17 bar and then removes this from the high pressure system during the controlled reduction of pressure into a thermal processing system.
2. A process for expanding tobacco by impregnation with gas and subsequent thermal processing, in which one exposes tobacco with a moisture content in the range from 20 to 40%-wt (on the basis of the dry weight of the tobacco) at a temperature in the range from approximately -10 to +10°C, to a carbon dioxide gas atmosphere at a pressure in the range from 3 to 17 bar, reduces the pressure in a passage that can be sealed off from the high pressure system, the impregnated tobacco being heated during the pressure reduction phase and then removed into a thermal processing system.
3. A process for expanding tobacco by impregnation and subsequent thermal processing, in which one impregnates the tobacco at above atmospheric pressure with a gaseous impregnating medium, reduces the pressure in a passage that can be sealed off from the high pressure system, when the impregnated tobacco is heated during the pressure-reduction phase, and then emptied into a thermal processing system.
4. A process as defined in claim 1 or claim 2, characterized in that one permits the tobacco to absorb up to approximately 1%-wt, preferably 0.6 to 1%-wt carbon dioxide (relative to the dry weight of the tobacco) during impregnation.
5. A process as defined in claim 1 or claim 2, characterized in that one impregnates tobacco with a moisture content in the range from 20 to 33%-wt, and in particular from 25 to 33%-wt.
6. A process as defined in one of the claims 2, 4, or 5, characterized in that one impregnates the tobacco at a temperature in the range from -10 to +5°C, or -7 to +5°C.
7. A process as defined in one of the claims 2, 4, or 5, charactereized in that one impregnates the tobacco at a temperature in the range from approximately -10 to 0°C, and in particular from -10 to -5°C.
8. A process as defined in one of the claims 1, 2, or 4 to 7, characterized in that one impregnates the tobacco at a pressure in the range from 3 to 10 bar.
9. A process as defined in one of the claims 2 to 6, characterized in that one exposes the impregnated tobacco to microwaves, an electrical alternating field, radiation heat, or contact heat for thermal processing during the pressure-reduction phase.
10. A process as defined in claim 9, characterized in that one exposes the impregnated tobacco to hot gas such as hot air or hot carbon dioxide during the pressure-reduction phase, which can encompass the steam and which preferably is at a temperature in the range from 60 to 220°C, for example 150 to 220°C.
11. A process as defined in claim 9, characterized in that during the pressure-reduction phase, one exposes the impregnated tobacco to steam that is preferably at a temperature in the range from 60 to 220°C, for example 150 to 220°C.
12. A process as defined in one of the preceding claims, characterized in that one effects the pressure reduction in one stage or in a plurality of stages, for example, in two stages.
13. A process as defined in claim 12, characterized in that one effects the pressure reduction in one stage or in two stages within a time frame in the range of 0.1 to 5 seconds.
14. A process as defined in claim 12, characterized in that one effects the pressure reduction in more than one stage and makes provision for a residence time in the range from 0.1 to 3 seconds at each stage.
15. A process as defined in claim 12 or claim 13, characterized in that one reduces the pressure in two stages, and during the first stage to a pressure in the range from 2 to 4 bar.
16. A process as defined in claim 12 or 13, characterized in that in the first stage one reduces the pressure from approximately 10 bar to approximately 3.5 bar, and in the second stage reduces the pressure to atmospheric pressure or below.
17. A process as defined in claim 12, characterized in that one effects the pressure reduction in a number of stages, and the thermal processing according to one of the claims 8, 9, 10 or 11 during all the pressure-reduction stages or only in one part thereof.
18. A process as defined in one of the claims 12 to 17, characterized in that one operates in the particular pressure-reduction stage cyclically such that one first raises the pressure to the value below which the tobacco that is to be introduced into the pressure-reduction stage is at, and then moves the tobacco in and reduces the pressure, moves the tobacco out of the pressure-reduction stage, and then begins a new cycle.
19. A process as defined in claim 18, characterized in that during the pressure-reduction phase, one returns any gas escaping from the pressure-reduction stage, in particular impregnating gas and/or hot gas, in the circulation circuit to the pressure-reduction stage.
20. A process as defined in one of the preceding claims, characterized in that one effects the thermal treatment after the pressure-reduction phase at atmospheric pressure or below.
21. A process as defined in one of the preceding claims, characterized in that one carries out the thermal processing after the pressure-reduction phase with a hot gas, such as hot air, which can encompass the steam, or with steam.
22. A process as defined in claim 21, characterized in that one uses hot gas or steam at a temperature in the range from 60 to 300°C, preferably 120 to 300°C, in particular 160 to 220°C, for example 80 to 220°C.
23. A process as defined in one of the preceding claims, characterized in that one uses rib cut, reduced leaf tobacco or leaf tobacco cut as the tobacco.
24. An apparatus for producing expanded tobacco, in particular for carrying out the process as defined in one of the preceding claims, and consisting of or including a thermally insulated and/or coolable impregnating apparatus and a subsequent thermal processing system.
25. An apparatus as defined in claim 24, characterized in that the impregnating system includes an autoclave or a plurality of autoclaves that can be arranged in parallel or in series.
26. An apparatus as defined in claim 25, characterized by two autoclaves that can be charged with tobacco or from which the tobacco can be removed in alternation.
27. An apparatus as defined in claim 25 or claim 26, characterized in that each autoclave incorporates a mixture, for example with a paddle mixer, to loosen the tobacco that is to be impregnated.
28. An apparatus as defined in claim 27, characterized in that each autoclave incorporates a rotating drum that is fitted with paddles, wherein the drum and optionally the autoclave can be arranged approximately horizontally or inclined.
29. An apparatus as defined in claim 27, characterized in that each autoclave is configured as a drum (2) and is arranged approximately horizontally or so as to be inclined.
30. An apparatus as defined in one of the claims 24 to 29, characterized in that the impregnating system is connected to the heating system through a pressure-reduction system.
31. An apparatus as defined in claim 30, characterized in that the thermal processing system is connected directly to the pressure-reduction system.
32. An apparatus as defined in claim 30 or claim 31, characterized in that the pressure-reduction system is in the approximate shape of a pipe.
33. An apparatus as defined in claim 30, characterized in that the pressure-reduction system is arranged so as to be approximately vertical.
34. An apparatus as defined in one of the claims 31 to 33, characterized in that the pressure-reduction system incorporates at least at its inlet and at its outlet a pressure lock (22a, 22b) or a slide.
35. An apparatus as defined in one of the claims 31 to 33, characterized in that the pressure-reduction system has a lock at the inlet, a lock at the outlet, and an additional lock that is arranged between the other two locks.
36. An apparatus as defined in one of the claims 31 to 35, characterized in that the pressure-reduction system incorporates a generator for microwaves or for an electrical alternating field, or with at least one inlet for a heated gaseous medium.
37. An apparatus as defined in claim 36, characterized in that the inlets for the heated gaseous medium are arranged on the periphery of the pipe-like pressure-reduction system.
38. An apparatus as defined in claim 36 or claim 37, characterized by a circulating system, that includes a pump, a controller, a heat exchanger, and optionally an accumulator, with the help of which heated gaseous medium can be returned to the pressure-reduction system through the circulation system after leaving the pressure-reduction system.
39. An apparatus as defined in one of the claims 24 to 37, characterized by a pneumatic channel (16) as a thermal processing system.
]
]
40. An apparatus as defined in claim 39, characterized in that the pneumatic channel is arranged so as to be approximately horizontal.
41. An apparatus as defined in claim 39 or claim 40, characterized in that the pneumatic channel incorporates an inlet for super-heated steam.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3841915.7 | 1988-12-13 | ||
| DE19883841915 DE3841915C1 (en) | 1988-12-13 | 1988-12-13 | Tobacco heat treatment plant - incorporates drums with wetting jets and revolving blades |
| CH89.03165 | 1989-09-01 | ||
| CH316589 | 1989-09-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2005332A1 true CA2005332A1 (en) | 1990-06-13 |
Family
ID=25692355
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2005332 Abandoned CA2005332A1 (en) | 1988-12-13 | 1989-12-13 | Method of and apparatus for expanding tobacco |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0400131A1 (en) |
| AU (1) | AU4803090A (en) |
| CA (1) | CA2005332A1 (en) |
| WO (1) | WO1990006695A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0394665A (en) * | 1989-06-19 | 1991-04-19 | R J Reynolds Tobacco Co | Method and apparatus for treating tobacco material |
| JP3140039B2 (en) * | 1990-11-07 | 2001-03-05 | 日本たばこ産業株式会社 | Flash drying method and apparatus for tobacco raw materials |
| US5251649A (en) * | 1991-06-18 | 1993-10-12 | Philip Morris Incorporated | Process for impregnation and expansion of tobacco |
| US5259403A (en) * | 1992-03-18 | 1993-11-09 | R. J. Reynolds Tobacco Company | Process and apparatus for expanding tobacco cut filler |
| SK139993A3 (en) * | 1992-12-17 | 1994-09-07 | Philip Morris Prod | Method of impregnation and expanding of tobacco and device for its performing |
| DE10038114A1 (en) * | 2000-08-04 | 2002-02-21 | Bat Cigarettenfab Gmbh | Method and device for conditioning shredded tobacco materials |
| DE10046124C1 (en) * | 2000-09-15 | 2002-07-04 | Reemtsma H F & Ph | Process for improving the fillability of tobacco |
| DE10304629B4 (en) * | 2003-02-05 | 2008-10-30 | British American Tobacco (Germany) Gmbh | Pressure conditioning process |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU525910B2 (en) * | 1978-03-29 | 1982-12-09 | Philip Morris Products Inc. | Puffing tobacco leaves |
| US4561453A (en) * | 1981-12-16 | 1985-12-31 | Rothchild Ronald D | Treatment of tobacco under pressure in a continuous process |
| GB2115677A (en) * | 1982-01-08 | 1983-09-14 | Ronald D Rothchild | A method for expanding tobacco |
| CA1328064C (en) * | 1987-07-27 | 1994-03-29 | Masao Kobari | Apparatus for expanding material for foodstuffs, favorite items and the like |
-
1989
- 1989-12-13 WO PCT/EP1989/001533 patent/WO1990006695A1/en not_active Application Discontinuation
- 1989-12-13 AU AU48030/90A patent/AU4803090A/en not_active Abandoned
- 1989-12-13 EP EP19900900170 patent/EP0400131A1/en not_active Withdrawn
- 1989-12-13 CA CA 2005332 patent/CA2005332A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU4803090A (en) | 1990-07-10 |
| WO1990006695A1 (en) | 1990-06-28 |
| EP0400131A1 (en) | 1990-12-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |