Note: Descriptions are shown in the official language in which they were submitted.
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Process for treating a material by extrusion
and an apparatus for producing a composite
Good product
BACKGROUND OF THE INVENTION
The present invention relates to an improved prGcess
for treating a material by extrusion, an apparatus for
carrying out the process and also products produced by
the process.
Extrusion machines are employed for effecting various
treatments carried out on very varied materials. For
example, there may be effected in screw machines treatments
for preparing and employing food nroducts, for example by a
IO cooking-extrusion process
GeneraIly, a screw extrusion machine comprises an
elongated sleeve surrounding at least one screw driven in
rotation on which treatlng means are fixedjsuch as screw-
threads extending in a helix around the axis. In the vase
of an extrusion machine having a plurality of screws
having paxallel axes, the screws are placed within lnter-
secting bores formed in the sleeve and having diameters
exceeding the distance between the axes so that the mate-
; rial fed through an inlet orlfice placed adjacent an
; 20 upstream end of the sleeve is driven toward the downstream
end by the combined effects of the rotation of the screws.
The screwthreads may have sections with a varied pitch
which permits effecting, in the direction toward the
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downs-tre~m end, various treatments such as the mixing of the
cons-tituents introduced througll the inlet orifice, the
kneading of -the material, the cooking in a thin layer in the
case of food products; as the sleeve may be provided in
certain sections with heating iackets or cooling jackets the
product driven by the screws may be brougl~t to or maintained
at a given temperature.
But the continuous production of a composite food
product, i.e. a product comprising a plurality ox regions
which are coloured and/or aromatized in a different manner,
from a single material treated in an extrusion machine,
poses problems in particular as concerns the injection of
the various colouring and aromatizing agents, and also as
concerns the formation of these different regions in a
single product.
SUMMARY OF THE INVENTION
Now, investigations which have lead to the
invention have shown that it was possible to obtain this
type of new products having characteristics of particular
interest.
According to the present invention, there is
provided a process for treating a material by extrusion in a
machine comprising at least one screw driven in rotation
within an elongated sleeve and provided with helical threads
which drive toward the downstream end ox the machine the
material introduced through an inlet orifice placed adjacent
to the upstream end of the sleeve, comprising causing the
material to pass through the outlet of a first treatment
region into a second treatment region defined by a second
sleeve, dividing said material into a plurality of
-independent fluxes, subjecting each flux to a particular
treatment, and then conveying the independent fluxes into a
third region and forming a final single product.
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The invention permits the preparation oE product
in the desired manner, Eor example by a cooking-ex~rusion
process, in the first -treatment region, and then the
separation of the product into a plurali-ty of fluxes which
are mixed with different aromas or colouring agents in the
separate bores of thy second region.
But the invention also permits dividing a product
previously prepared in the first treatment region into a
plurality of fluxes which are subjected, for example, to
different chemical reactions for achieving, for example, an
expansion or a reduction of the product or for providing
textures of different nature.
According to the present invention, there is also
provided an apparatus for producing a composite food product
by extrusion, comprising a machine including an elongated
sleeve having an upstream inlet orifice and a downstream
outlet orifice, a screw driven in rotation inside the
elongated sleeve and provided with helical threads for
driving the material introduced through the inlet orifice
toward the downstream end, said apparatus further comprising
a second part for treating the material and comprising a
second sleeve defining separate bores for forming a
plurality of independent fluxes of material, a common
convergent portion, and a third part formed by an extrusion
die having a central extrusion conduit of given length and
section and put in communication with said separate bores
through said convergent portion.
According to the present invention, there is also
provided an apparatus for producing a composite food product
by extrusion comprising a machine including an elongated
sleeve having an upstream inlet orifice and a downstream
end, at least two screws having parallel axes and each
formed by a central driving shaft and helical threads
disposed within said sleeve, the material being fed through
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the inlet orifice and then driven toward the downstream end
of the sleeve by the rotatlon fo the screws, said apparatus
further comprising a second par-t for treating the material
and comprising a second sleeve defining separate bores for
forming a plurality of independent Eluxes of material
centered on axes of the screws, said screws being each
extended inside the correspond.ing bore by a downstream
portion acting as a mono-screw and provided with threads,
and each of said bores of the second part opening into a
third part formed by an extrusion die.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be better understood from the
detailed description of several embodiments given by way of
example and shown in the accompanying drawing. In the
drawing:
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Fig. l is a diagran~atic axiaL sectional view of a
first embodiment of the inventlon ;
Fig. 2 is a diagrammatic axial sectional view of a
second embod1ment of the invention ;
Figs. 3 and 4 are two cross~sectional views in
planes A-A and BOB of Fig. 2 ;
Figs. 5 and 6 are modifications of the construction
of the extrusion die ;
Figs. 7 and 8 are cross-sectional views of two exam-
ples of products pxoduced by the process according to the
invention.
DESCRIPTION OF PRE:FERRED EMl~ODIMENTS
Fig. 1 shows diagrammatically an apparatus for carry-
ing out the process according to the invention and formed
by a machine having a plural:ity of treatment regions.
The upstream region I comprises a conventional screw
extrusion machine. It therefore comprises an elongated
sleeve 1 in which there is placed a screw 20 driven in
rotation by a motor-speed reducer unit 3. The screw 20
is formed by a central driving shaft 21 on which a screw-
thread 22 extends in the form of a helix. The pitch and
the depth of the thread 22 are determined in accordance
with the treatment it is desired to effect on the material
introduced through a supply orifice 4 formed at the up-
stream end of the sleeve and driven toward the downstreamend by the rotation of the screw 20.
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Further, in a given section of the sleeve 1, the
latter may be surrounded by a jacket (not shown) whereby
it is possible to heat or cool and consequently bring
the material to a desired temperature or regulate this
temperature.
The upstream region I is followed by a second region
II in which separate treatments may be carried out.
For this purpose, the sleeve 1 is extended by a
second sleeve 5 in which are formed two separate bores 50
and 51 for forming two independent fluxes A and B of the
material prepared in there~ion I. The sleeve 5 is provided
with two orifices 52 and 53 opening onto the two bores 50
and 51 and permitting the introduction of different pro-
ducts in the two fluxes of material A and B. It is also
possible to place in one or hoth bores 50 and 51, a static
mixer 54 for homogeneizing the corresponding flux of
material. The bores 50, 51 terminate in a common conver-
gent portion which terminates in a single orifice 7.
This second treatment region II is followed by a
third region III formed by an extrusion die 6 provided
with a central extrusion conduit 60. The latter has a
length which is so determined that the fluxes A and B are
applied against each other and become unitary,as will be
seen hereinafter.
Owing to this arrangement, the material fed through
the inlet orifice 4 i5 subjected to the required treatment
in the first region I of the machine and is then divided
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into -two lndependent fluxes A and B in the second region
II. This second region permits the applica-tion of diffe-
rent treatments to the two fluxes coming from the same
material and, in particular, the introduction through
orifices 52 and 53 of colouring agents and/or different
aromas or flavourings, the static mixer 54 t.hus homoge-
neizing the mixture.
ThereaEter, aster the two fluxes A and B have been
subjected to a different treatment, they are conveyed
through the convergent portion 55 to the extrusion conduit
of the extrusion die 6 where they are grouped together
into a single flux. At the outlet of the die 6, the
material issues at a certain pressure and is subjected to
atmospheric pressure and the shock due to this sudden
pressure difference brings about an exoansion of the
material.
In the extrusion conduit 60, the two fluxes A and B
are maintained aPplied against each other throughout the
length of said conduit so as to achieve the adhesion of
these two fluxes and obtain continuously at the outlet
of the die a final product having on its transversely
extending end and throughout the length, two coloured
and/or aromatized regions of different types as shown in
Fig. 7 in which the two fluxes A and B are shown adhexed
to each other.
The interconnection of the two fluxes is achieved,on
one hand, owing to the symmetrical flow in the second
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zone II of the fl.uxes A and B which are maintained a-t the
same velocity and at the same temperature so as to retaln
the same characteristics of the material and, on the
other hand, owing to the length of the extr.usion conduit
60, which during a given period of time, exerts suffi-
cient pressure on these two fluxes.
Fig. 2 shows a second embodiment of the invention
in which the upstream region I is formed by a conventio-
nal double-screw extrusion machine. It also has an
elongated sleeve 1 in which are placed two screws 30 and
40 driven in rotation about their parallel axes by a
motor-speed reducer unlt 3. Each screw is formed by a
central driving shaft 31, 41 on which extend helical
screwthreads 32 and 42 which engage with each other. The
two screws may be formed by successive sections having
different pitches so that it is possible to subject the
material,introduced through the supply orifica 4 provided
at the upstream end of the sleeve and driven toward the
downstream end by the rotation of the screws,to varied
treatments.
As can be seen in Fig 3, the sleeve 1 is provided
with two bores la and lb of diameters equal, apart from
clearance, to the diameter of thy two screws and conse-
quently greater than the distance a between the axes,
the two bores being therefore intersecting in a median
region corresponding to the interengagement of the two
screws.
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further, in a given section of the sleeve 1, the
latter may be surrounded by a jacket for heating or cooling
and consequently for bringing the material to a desired
temperature or regulating the latter.
Depending on the contour given to the two screws, any
known treatment ox the material may be carri.ed out within
the section I of the machine. The upstream region I is
also followed by a second region II in which s.eparate treat-
ments may be carried out. The sleeve 1 is therefore exten-
ded by a second sleeve 5 in which are ormed two separate
bores 50 and 51 for forming two independent fluxes and B
of the material prepared in the region I. The sum of the
radii of the two separate bores 50 and 51 is less than the
distance a between the axes of the two screws. Conse-
quently, as shown in Fig. 4, the two bores 50 and 51 do notintersect.
The two screws 30 and 40 are each extended in the
corresponding bore 50, 51 by a downstream portion 33, 43
respectively, which i5 mounted in the corresponding bore
50, 51. Each screw 33, 43 is formed by a shaft, 34 and 44
respectively, on which extends a helical screwthread 35 and
45 respectively. The two shafts 34, 44 are placed in the
extension of the shafts 31, 41 of the two screws 30, 40 and
driven in xotation with the latter. The threads 35, 45
haze diameters which are equal, apart prom clearance, to the
diameters of the bores 50 and 51, As in the foregoing embo-
diment, the sleeve 5 is provided with two oriices 52 and 53
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opening into the two bores 50 and 51 or introducing various
additives in the two fluxes A and B of material.
Further, each bore 50~ 51 is extended by a convergent
portion 56 and 57 which terminate in an orifice 8 and 9
respectively. Each screw 33, 43 is provided with a poi.nted
portion which enters the corresponding convergent portion.
The treatment region II formed by the sleeve 5 is
followed by a third region III formed by an extrusion die
6a. The latter comprises for each flux A and B, in front
of each orifice 8, 9, a distribution passageway 61 and 62
respectively, which are symmetrical to each other and
converge to a common extrusion conduit 60a.
In this embodlment employing a double screw machinel
the material fed through the inlet orifice 4 is subjected
to the desired treatment in the first region I and is then
divided in the region II into two independent fluxes A and
B driven by the screws 33, 43 which operate as a mono-screw.
This second region II permits the introduction through the
orifices 52 and 53 of different colouring agents and/or
aromas or flavourings, the screws 33 and 43 homogeneizing
the mixture in each flux.
Thereafter, when the two fluxes;A and B have been suh-
jected to a different treatment, thy are conveyed by the
convergent portions 56, 57 to the distribution passageways
61, 62 and then they are re-grouped into a single flux in
the extrusion conduit 60a of the extrusion die 6a. In this
conduit 60a, the two fluxes A and B become unitary for the
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previously explained reasons.
where is thus obtained from a slngle material treated
in a double-screw machine, a final product comprising two
differently coloured and/or aromatized regions.
Owing to the invention, it is also possible to arrange
that the two mono-screws 44, 43 lead to concentric extru-
sion dies (Fig. 5) which permit the production of a filled
product by co-extrusion.
In this embodiment, the third region III is formed by
an extrusion die 70 having, for each flux A and B, in front
of each orifice 8, 9, a distribution passageway 71 and 72
respectively. Each distribution passageway 71 and 72 commu-
nicates with an extrusion conduit 73 and 74, the conduit 74
being concentric with the conduit 73. The flux A is there-
lS fore conveyed by the distribution passageway 71 to theconduit 73 so as to form the external material of the
- product, while the flux B is conveyed by the passageway 72
to the conduit 74 for forming the filling of the product.
Thus, it can be seen that, with the use of the same starting
JO material, it will be possible to produce a product, as shown
in Fig. 8, having a filling and a covering which are diffe-
rent as concerns their taste, their texture, or their
appearance.
In order to increase the delivery or flow o the final
product, the extrusion die may obviously include a plurality
of extrusion conduits, as shown in Fig. 6. In this case, in
respect o each flux A and B, the distribution passageways
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11 and 12 of the extrusion die 10 are divlded into sub-
passageways lla, llb and 12a, 12b respectively, whlch
converge in pairs toward an extrusion conduit 13, 14. The
path of flow of each flux A and in the passageways and
the sub-passageways is symmetrical.
The machines described hereinbefore may be completed
by a device for cutting the extruded products. The section
of the extrusion dies may be varied for extruding products
of different shapes. Further, the material issuing from
the first treatment region slay be also separated into a
plurality o independent fluxes which are subjected to
different treatments, these fluxes being thereafter re-
grouped in a single extrusion conduit so as to provide a
final product having, on the transverse end and throughout
the length thereof, a plurality of differently coloured
and/or aromatized sectors.
Owing to the invention, it is thus possible to extrude
in the same machine and from the same material a composite
food product without necessity to produce the different
elements thereof separately or to employ a plurality of
machines.
Various modifications and improvements may be made in
the process and apparatus according to the invention within
the scope of the accompanying claims.
