U.S. patent number 3,894,544 [Application Number 05/421,242] was granted by the patent office on 1975-07-15 for process for producing tobacco structures.
This patent grant is currently assigned to Tamag Basel AG. Invention is credited to Laszlo Egri.
United States Patent |
3,894,544 |
Egri |
July 15, 1975 |
Process for producing tobacco structures
Abstract
A process and device for the production of coherent tobacco
structures of coarse comminuted tobacco materials, in particular
ribs and wastes, wherein the starting tobacco material is
comminuted in a coarse grinding device to a particulate size of
approximately 150-200 .mu.m; moistened with a liquid, consisting of
an alkali and/or silicic acid sol, in a weight ratio of
approximately 1:1.1 to 1:1.5 tobacco to liquid; kneaded in a mixing
device to form a dough-like mass which is then shaped to form
leaf-like structures; and applied in dosed amounts to a plastic
transport belt whereupon the separate portions are spread under
pressures up to a maximum of approximately 20 kg/cm.sup.2 (approx.
284.4 psi) to form individual flakes by means of a plastic
spreading belt which runs in the same direction as the transport
belt, but at a somewhat slower speed.
Inventors: |
Egri; Laszlo (Basel,
CH) |
Assignee: |
Tamag Basel AG (Birsfelden,
CH)
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Family
ID: |
27431509 |
Appl.
No.: |
05/421,242 |
Filed: |
December 3, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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284677 |
Aug 29, 1972 |
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Foreign Application Priority Data
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May 23, 1973 [GR] |
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2003 |
Jun 2, 1972 [DT] |
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2230314 |
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Current U.S.
Class: |
131/370 |
Current CPC
Class: |
A24B
3/14 (20130101) |
Current International
Class: |
A24B
3/14 (20060101); A24B 3/00 (20060101); A24b
003/14 () |
Field of
Search: |
;131/17,2,15,136,140-144 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,236,896 |
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Jun 1960 |
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FR |
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1,473,477 |
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Feb 1967 |
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FR |
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Primary Examiner: Rein; Melvin D.
Attorney, Agent or Firm: Cooper, Dunham, Clark, Griffin
& Moran
Parent Case Text
CROSS-REFERENCE
This is a continuation-in-part application based on my earlier
application Ser. No. 284,677 filed on Aug. 29, 1972, now abandoned
with claim to Convention priority based on West German application
Serial No. P 2230314.6 filed June 21, 1972. Convention priority for
this application is also claimed based on Greek application Ser.
No. 2003/17/6 filed May 23, 1973.
Claims
What is claimed is:
1. A process for the production of coherent tobacco structures of
coarsely comminuted tobacco materials, in particular ribs and
wastes, which are moistened and kneaded to form a dough-like mass
which is then shaped to form leaflike structures, wherein the
improvement comprises the steps of:
a. comminuting the starting tobacco material to a particulate size
of approximately 150 to 200 .mu.m;
b. moistening the comminuted tobacco by mixing with a liquid in a
weight ratio of 1:1.1 to 1:1.5 tobacco to liquid;
c. kneading the moistened tobacco material to form a dough-like
mass;
d. directly applying the dough-like mass to a transport belt in
individual, separate portions to form spaced pieces; and
e. then spreading the portions on the transport belt under
relatively low compression pressures up to a maximum of
approximately 20 kg/cm.sup.2 to form individual flakes by means of
a spreading belt which runs in the same direction as the transport
belt and at a speed slightly slower than the transport belt.
2. A process according to claim 1 wherein the moistening liquid
comprises a liquid which softens the tobacco material and which is
selected from the group consisting of an alkali, and a silicic acid
sol.
3. A process according to claim 1, wherein the spreading belt is of
plastic.
4. A process according to claim 3, wherein the transport belt
and/or the spreading belt is driven by several small rollers driven
by the same motor and whose mutual spaced relation can be
adjusted.
5. A process according to claim 1, wherein the tobacco flakes are
separated from the belt by external heating and/or treatment with a
lubricant.
6. A process according to claim 5 wherein the lubricant is selected
from the group consisting of diethylene glycol, glycerin, silicon
oil and combinations thereof.
7. A process according to claim 1 wherein the tobacco flakes are
transferred from the transport belt to a plastic conveyor belt and
then dried thereupon.
8. A process according to claim 1 wherein the size of the portions
is selected such that tobacco flakes are formed which can be
directly used as a cigar filler without subsequent comminution.
9. A process according to claim 1 wherein the size of the portions
is selected such that tobacco flakes are produced which can be
mixed to form cigarette tobacco without subsequent comminution and
can be fed into a conventional cutting machine for cigarette
tobacco.
10. A process according to claim 1 wherein the kneaded mass is
extruded through a perforated plate and is subsequently reduced in
size to form pieces approximately 3 mm in diameter and
approximately 5 mm in length.
11. A process according to claim 1 wherein the size of the portions
is selected such that tobacco flakes are produced which have an
area of about 1 cm.sup.2.
Description
BACKGROUND OF THE INVENTION
This invention relates to a process for the production of coherent
tobacco structures of coarsely comminuted tobacco materials, in
particular ribs and wastes, which are moistened and kneaded to form
a dough-like mass which is then shaped to form leaf-like
structures. In all of the known processes for producing
reconstituted tobacco from tobacco wastes, ribs etc., the
reconstituted tobacco is first produced in the form of a coherent
endless band of fibers. This primary product is continuously
removed from appropriate shaping machines and/or from a transport
belt and is then reduced in size to form so-called flakes or
tobacco flakes or may be cut to a desired width. This mode of
operation suffers from the drawback that the reconstituted tobacco
structure has a paper-like flat shape and thus has a poor filling
capacity.
Proposals are also known for producing tobacco paste through the
small opening of an extruder or by specially designing a band in
the shape of a fiber. In spite of the apparent simplification of
the direct method of fiber production which is supposed to be
offered by such processes, it is especially disadvantageous in
practice because, among other things, the tobaccos used for smoking
articles are of different kinds and the fiber shapes cannot be
mixed with each other, since otherwise greater amounts of waste
would be formed.
The present invention provides a process of the type discussed
above which overcomes the cited drawbacks of the known processes
and at the same time permits production of an end product which is
more favorable with respect to both quality and health than can be
obtained from the same starting material with the known processes
and an apparatus for performing the process.
SUMMARY OF THE INVENTION
The present invention involves a process for the production of
coherent tobacco structures embodying the use of a coarse grinding
device, e.g., a hammer mill which comminutes the starting tobacco
material, such as ribs and wastes, to a particulate size
approximately 150-200 .mu.m; a moistening device for admixing the
comminuted tobacco material with a liquid, consisting of an alkali
and/or silicic acid sol, expediently in a weight ratio of
approximately 1:1.1 to 1:1.5 tobacco to liquid; a softening silo
into which the moistened tobacco material is fed containing a
mixing means and a continuously operating discharge device whereby
the capacity of the silo is matched to the flowthrough rate such
that the average residence time of the moist tobacco material in
the silo amounts to at least 1 hour; a continuously operating
kneading device which receives the discharged moist tobacco
material and subjects it to an intensive mixing, kneading and
shearing process without an appreciable reduction in size while
supplying additives thereto; a dosage device which doses the
dough-like mass emerging from the kneading device into portions of
predetermined size; and a shaping device in the form of an endless
plastic transport belt which receives the portions from the dosage
device at specific intervals and a plastic spreading belt running
in the same direction as, but at a slightly slower speed than, the
transport belt and cooperating with it to spread the portions under
pressures up to a maximum of approximately 20 kg/cm.sup.2 (approx.
284.4 psi) to form individual flakes.
BRIEF DESCRIPTION OF THE DRAWING
Other and further features of the invention will now be more
particularly described with reference to the accompanying drawing
which is a schematic view, in part in sectional elevation, showing
a preferred embodiment of a device in accordance with the invention
for carrying out the process of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with the invention, the starting tobacco material,
after being formed into a dough-like mass, is directly applied to a
transport belt in individual, separate portions and the portions
are then spread under pressures up to a maximum of approx. 20
kg/cm.sup.2 (approx. 284.4 psi) to form individual flakes by means
of a spreading belt which runs in the same direction as, but at a
slightly slower speed than, the transport belt.
The tobacco material used as the starting material in the process
is comminuted to a particulate size of approximately 150-200 .mu.m
and admixed with a liquid, expediently in a weight ratio of
approximately 1:1.1 to 1:1.5 tobacco to liquid. Before further
processing to form a dough-like mass, it is advisable to let the
mixture of tobacco material and liquid stand and soften for a
considerable period of time, preferably at least 1 hour. It is
especially expedient during softening to maintain the mixture at an
elevated temperature or to heat it preferably to temperatures up to
100.degree. C.
The tobacco materials soaked with the liquid, in particular ribs or
tobacco scrap, will be found to heat up by themselves under
suitable conditions when left to stand, probably due to
fermentation processes. Accordingly, if desired, and in particular
when the cried inherent cited of heat is not sufficient, the
tobacco material mass soaked with the solution may be heated to
temperatures, preferably in the range from 30.degree. to 70.degree.
C. The use of a tobacco material-liquid weight ratio in the
afore-cited range is especially advantageous if the moistened
tobacco material is to be heated to an elevated temperature by
means of fermentative heating during the resting period. It has
been found that if at least an equal amount by weight of silicic
acid sol is not admixed with the tobacco material to be treated,
then difficulties will arise with regard to the uniform moistening
of each individual tobacco particle. This problem arises
particularly with tobacco material mixtures whose individual
components differ with regard to the capacity to absorb moisture,
since the major portion of the employed liquid is taken up in this
case by the especially hygroscopic components of the mixture while
the remaining tobacco parts, e.g., ribs, remain almost dry.
On the other hand, excessive amounts of liquid, that is, amounts
which surpass the cited maximum limit of the afore-cited quantity
ratios, not only impair the economy of the process by increasing
drying expenditure, but also have a disadvantageous effect on the
enzymatic and/or microbiological fermentation processes which lead
to the desired inherent heating of the moistened tobacco
material.
When a stack of tobacco is opened after fermentative heating, a
small percentage of the admixed liquid evaporates without the
application of drying energy from the outside. The tobacco material
mass in this state is preferably introduced into a stirring means
or into a kneading and mixing device where the individual particles
are intimately mixed and are pressed together. The dough-like mass
which is obtained in this manner can then be directly processed to
form tobacco-like structures (tobacco flakes) in accordance with
the invention.
Known additives such as burn promoters, moistening and binding
agents, etc., can be admixed with the tobacco material mass
depending on the properties of the tobacco and according to the
desired results.
In the process of the invention, a relatively coarsely comminuted
tobacco material is used as the starting material as already
mentioned. The grain is preferably selected such that the tobacco
material remains almost completely on a sieve having a mesh size of
0.24 mm (or 0.0098 in. based on the German Industrial Standard DIN
1171). The grain size distribution of the tobacco material before,
and after the processing of the moistened tobacco material which
has been softened at an elevated temperature to form a dough-like
mass, is not critical; they are preferably selected, however, to be
as coarse as possible in order to keep the plant and operational
costs for grinding the starting material as low as possible. A
particle size of about 1.0 mm (0.0394 in.) and preferably about 0.5
mm (0.0197 in.) should expediently not be exceeded.
Preferably alkaline liquids are used for mooistening and softening
the tobacco material. Very good results may also be obtained with
most tobacco materials using silicic acid sols whose pH value is
between about 7.5 and 9. In specific tobacco sorts, however, acidic
liquids with a pH value of up to about 4 may also be found
favorable.
The use of aqueous silicic acid sols is especially expedient. The
silicic acid sols offer in particular the following advantages:
1. Due to their alkalinity, they have an especially marked
softening effect and hydrolize the binding substances, e.g.,
pectins, specific for tobacco.
2. The silicic acid contained in the silicic acid sols is
distributed very finely and uniformly in the tobacco material and
even partially penetrates into the cells so that the silicic acid
can be precipitated out as an extremely fine and uniformly
distributed gel with a high adsorption capacity after it has been
mixed with the tobacco material. The silicic acid gel acts as a
built-in adsorption filter for the tobacco smoke and consequently
leads to milder products which are also lower in nicotine and
tars.
Since most tobacco materials become bitter when treated with strong
alkaline liquids, i.e., they supply a bitter and sharp-tasting
smoke, it is advisable to neutralize the alkalinity to a pH value
of from 9 to 7 and in particular to at least 8.5 when using such
alkaline liquids, for example alkaline silicic acid sols, to
moisten the tobacco material.
The pH value of the treated tobacco material should, as a rule, not
be shifted if at all possible. It is therefore advisable to treat
most cigar tobaccos with weak alkaline liquids whose pH value, for
example, lies in the afore-cited range. Certain naturally weakly
acidic cigar tobaccos, however, should be treated with weakly
acidic to neutral liquids, for example, having a pH value of about
4 to 7 and in particular about 4.5 to 6.5.
Since no coherent endless tobacco structures are produced in the
process of the invention, there is no great need for creating a
resistance to tearing of the compacted products (in the shape of
tobacco leaves) so that the amount of foreign binders, e.g.,
carboxymethyl cellulose, etc., can be reduced to a greater or
lesser degree as compared to the known processes and the use of a
binder foreign to tobacco can even be entirely eliminated in
certain cases. In addition, the mode of operation proposed in
accordance with the invention offers the advantage that the small
leaf parts or tobacco flakes obtained by compacting portions of the
dough-like mass on the belt are thinner at the edge than the middle
parts of the tobacco flakes separated therefrom. Thus, the edge
parts dry faster, i.e., drying of the separated structures, similar
to a tobacco leaf, takes place non-uniformly, thereby yielding wavy
tobacco flakes which have a substantially more favorable filling
capacity than, for example, flakes obtained by cutting endless
tobacco foil bands.
In a preferred embodiment of the device for carrying out the
process of the invention, two plastic belts are provided between
which the portions of the dough-like mass are shaped into tobacco
flakes.
These plastic belts are advantageous due to the fact that very long
devices do not have to be built, such as used up to the present
time, because of the feasibility of transporting the transport belt
carrying the tobacco flakes back and forth under the shaping plane
by means of guide rollers. In this case, the lower side of the
transport belt supporting the tobacco flakes may be heated and the
belts may also have a gauze-like structure which permits quicker
drying.
As has already been stated above, the tobacco material moistened
with liquid is processed in a continuously operating mixing and
kneading device to form a dough-like mass before it is applied to a
transport belt in portions and compacted.
Comparison tests have shown that if tobacco material which has
merely been moistened with liquid, i.e., without a mixing and
kneading treatment, is applied in dosed amounts directly to the
transport belt, the moist tobacco material clumps are not compacted
to form sufficiently firm coherent tobacco flakes, but are shaped
into worm-like structures which are not a useful end product and
must therefore be shaped again.
Hence, the process of the invention makes it possible to operate
with an especially low compacting pressure although the starting
material is compounded with only a slight amount of liquid so that
only a slight amount of liquid must be removed by drying. This
fact, as well as the fact that the shaping of the dough-like mass
proposed in accordance with the invention between two belts running
at slightly different speeds, enables one to use cheaper, elastic
plastic belts in the process of the invention rather than expensive
metal belts which are susceptible to corrosion. A special advantage
of the inventive process is that it produces irregularly waved
flakes which have a large filling capacity.
By regulating the adherability of the compacted paste-like tobacco
flakes on the plastic transport belt, the lower or return side of
the endless belt, which heretofore has not been utilized, can now
be used to dry the tobacco flakes in accordance with the invention
by heating it thereby permitting the total length of the belt to be
reduced.
A further advantage is that the individual tobacco flakes can be
removed or peeled off the belt in the process of the invention
without having to completely dry them out or without having to
remoisten them again while on the belt as has been necessary in the
production of endless tobacco foil bands common up to now.
pg,11
Referring now particularly to the drawing, tobacco material T to be
processed to form tobacco structures is first coarsely comminuted
to the desired dimensions in a grinding device 1, such as in
particular a hammer mill without a filter insert. The tobacco
material T is then discharged preferably onto a transport device 2,
e.g., a conveyor belt which is expediently designed as a conveyor
type weigher, in dosed amounts. The tobacco material T on the
transport device 2 is then moistened, preferably by spraying a
liquid S in a weight ratio of approximately 1:1.1 to 1:1.5 tobacco
material to liquid, by means of a moistening device 3 which is
expediently equipped with spray nozzles 3a. In accordance with a
preferred embodiment of the apparatus in accordance with the
invention, the transport device 2 is designed as a conveyor type
weigher, as already mentioned above via a control device 23 by
means of which the applied amount of liquids is automatically
coordinated to the quantity of tobacco material T located on the
conveyor type weigher. The moistened tobacco material T leaves the
transport device 2 and arrives in a preferably heatable silo 4
which expediently has a discharge device 4a at its lower end which
continuously discharges the moistened and softened tobacco
material. The volume thereof is matched to the production capacity
of the apparatus such that the average residence time of the
moistened tobacco material amounts to at least 1 hour, preferably
at least about 2 hours. When processing tobacco material which
requires a softening time of appreciably more than 2 hours, two
parallelly arranged silos are preferably employed which are
alternately filled and emptied. If desired, the transport device 2
can be dispensed with if the grinding device 1 is disposed above
the silo 4 and the moistening device 3 is arranged such that the
coarsely comminuted tobacco material falling from the grinding
device 1 into the silo 4 is uniforly moistened. In this embodiment
of the apparatus in accordance with the invention, it is advisable
to equip the silo 4 with a stirring or mixing means 4b which is
effective at least in the upper part thereof. In order to be able
to soften the tobacco material at elevated temperatures, it is
advisable to design the silo 4 so as to be heated, for example, by
providing it with a vapor-heated double jacket 4c.
The moistened and softened tobacco material is transported from the
silo 4 directly into a continuously operating kneader 5, into which
the conventionally required tobacco additives, such as binders,
softeners and burn promoters, etc., are supplied in dosed amounts
from the reservoirs 6a, 6b, 6c. In accordance with the invention, a
kneader 5 is preferably used which comprises a rotor 5a provided
with blades and a stator 5b equipped with kneading teeth 5c as
essential parts. A very intensive shearing, compacting and kneading
effect is achieved due to the very narrow gaps between the rotating
blades and the stationary kneading teeth. The rotary movement of
the rotor is superimposed on an oscillating movement in kneading
devices preferably used for the purposes of the invention thereby
producing an optimum honogeneous distribution of the mixing
components.
The tobacco mass emerging from the kneading device 5 has a
dough-like character. The dough-like tobacco material mass leaves
the kneader 5 and is applied in a thickness corresponding to
portions or clumps via a dosage device 6 onto a transport belt 7.
The dosage device 6 may preferably be in the form of a perforated
plate through which the kneaded mass is extruded and subsequently
reduced in size to form pieces approximately 3 mm in diameter
(approx. 0.118 in.) and approximately 5 mm. in length (approx.
0.197 in.). Depending on the intended end use, the size of the
portions may be selected such that tobacco flakes are formed which
can be directly used as a cigar filler without subsequent
comminution or which can be mixed to form cigarette tobacco without
subsequent comminution suitable for feeding into a conventional
cutting machine for cigarette tobacco.
Transport belt 7 is preferably an endless plastic belt, which is
driven by means of one or more roller(s) 8, 8'. The tobacco clumps
or portions are then compressed to form tobacco structures using a
relatively low compressing pressure by means of an endless
spreading belt 7' which is preferably designed with perforations,
said belt running at a slightly slower speed than the transport
belt 7. The clumps of dough-like tobacco material mass are supplied
from the dosage device 6 to the transport belt 7 at mutual
distances which are set such that the compacted tobacco structures
do not overlap. In accordance with the invention, driving rollers
16, 16', which are especially driven by the same motor and which
expediently run synchronously with the roller or rollers 8, 8', are
provided as the drive system for the transport belt 7 and the
cooperating spreading belt 7', which is preferably of plastic as
well.
The compacted tobacco structures are then pre-dried on the
transport belt 7, preferably by means of a pre-dryer 9. After the
pre-drying operation, they are removed, for example, by means of a
scraper 10 and then conditioned, i.e., they are brought to the
desired final moisture content by expediently being conducted
through a conditioning drying device 12 on a conveyor belt 11 which
is preferably designed to be permeable to air.
It is advisable to coat the belt 7' with lubricants or separating
agents, such as silicon oils, diethylene glycol or glycerin and/or
to heat it in order to ensure that the compacted tobacco structures
adhere to the transport belt 7 practically completely when the
transport belt 7 is separated from the spreading belt 7'. The dried
tobacco structures are removed from the transport belt 7
expediently by means of the scraper 10.
The following examples are presented to illustrate the
invention.
EXAMPLE 1
10 kg Rio Grande ribs which have been comminuted in a hammer mill
without a sieve insert are stirred into 15 liters of water at a
temperature of 80.degree.C and are then left to stand for 2 hours.
The moistened tobacco material is then introduced into a
continuously operating kneader, 500 g of carboxymethyl cellulose,
500 g of diethylene glycol and 200 g of magnesium formiate being
admixed at the same time. The dough-like mass which continuously
emerges from the kneader in the form of a granulate is applied to
the transport belt in separated dosed portions. The tobacco paste
clumps are compacted on the transport belt to form flakes. The size
of the tobacco paste clumps is selected such that the individual
compacted tobacco flakes have an area of about 1 cm.sup.2 (0.155
sq. in.). Furthermore, the tobacco paste clumps are applied to the
transport belt in dosed amounts at such distances that the
compacted tobacco flakes do not come into mutual contact. The
tobacco flakes adhering to the belt are pre-dried for 10 seconds
and are then removed by means of a scraper. The already coherent
tobacco flakes are then conditioned on a perforated belt
driver.
EXAMPLE 2
1 kg of comminuted tobacco material consisting of 70% ribs and 30%
so-called tobacco scrap is moistened with 1.2 kg water while being
stirred. During further mixing of the mass, vapor is introduced and
attention must be paid to the fact that no condensation is formed.
The temperature of the tobacco mass is maintained at 70.degree. C.
After the mixture has been treated in the afore-stated manner for
one hour, it is further processed in a manner analogous to Example
1.
* * * * *