Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a continuous method
of manufacture of a sheet or an element formed by a uniform
fabric obtained by depositing a liquid, pasty or fibrous-
texture product on a wide travelling band.
Shee~s or elements of this kind, composed of a
uniform fabric, may be for example articles such as paper or
so-called non-woven fabrics. The use of these articles ne-
cessitates that their struc-ture should be very uniform and of
constant thickness.
~ow, the known methods of manufacture of these
sheets or elements do not make it possible to obtain the quali-
ties indicated above in a satisfactory manner.
In fact, ~or the manufacture of these sheets or
elements there is always employed a filtering open-mesh band,
on which is distributed a product generally consisting of
fibres in suspension in a liquid. The fibres are deposited on
; the band and the liquid, filtered through this latter, is
evacuated. The difficulties o:E formation of a structure of
the sheet or element which is very uniform and of constant
quality become increasingly great as the width o:E the band
employed increases, and with the known methods it is very
di~ficult to obtain a uniform distribution of the basic
product on the band.
A first conventional method, which may be termed the
"pouring method'l, consists of pouring the product on a flat
travelling band from a distribution tank provided with a slot
through which flows a curtain of the product which covers the
band from one edge to the other, transversely to its direction
o~ travel.
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With this method, it is particularly di~ficult to
control the flow of the product, and it will be understood
that a given material can only be adapted -to a relatively
narrow range of production rates. In fact, the product coming
into the distribution tank through the supply pipe has to pass
over different distances in order to reach the various points
of the formation band of the sheet or elemlent. This necessity
presents complicated hydraulic problems which can only be
satisfactorily resolved, for a given circuit, over a limited
range of flow-rates. Outside this range, turbulence and
faulty distribution occur, due to -the fact tha-t the source of
supply of product to the tank is not e~uidistant from the
various points on the width of the forming band.
In addition, such a method of distribution of the
product makes it difficult to obtain uniform laying of the
product on the band, and the sheet formed inevitably exhibits
defects (over-thicknesses, lumps, etc.), resul-ting from the
unsatisfactory dispersion of the fibres in the product to be
distributed.
In order to find a remedy ~or the major disad-
vantages of this method, and in order to restrict the bulk of
the equipment employed, a known alternative form of this
method consists of utilizing a deformable travelling band
which is led to be deformed by passing in-to a hollow body, and
to cause the product to fall by gravity on a disc housed ~ -
inside the hollow body and held in fluid~tight contact against
the de~ormed band, the liquid being extracted from the product
by suction and filtration through the meshes of the band.
While this alternative form of the pouring method
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makes it possible to control the flow of product and its
distribution more easily as a function of the speed of travel
of the band, and thus makes it possible to manufacture sheets
at relatively high speeds, it remains incapable of remedying
the other defect, namely the regularity of the final structure
of the sheet, since in fact, the mass of product poured on to
the disc is relatively stagnant and does not permit perfect
dispersion of the fibres throughout all the product, these
fibres having on the contrary a tendency to become agglomer-
ated in lumps.
There should be mentioned, furthermore, another
~nown method utilized for the distribution of the product on a
flat travelling band. This method consists of replacing the
linear supply by pouring, by a supply from a nozzle with a to-
and-fro alternating movement, emitting a small round jet; this
method may be termed a "projection method". The advantage of
this method resides in the fact that -the projection nozzle
ensures an e~cellent dispersion of the fibres and prevents the
deposit on the band of tufts of fibres, which was previously
; ZO the case in the pouring method.
In addition, the nozzle then permits suitable regu-
lation of the flow-rates of the product as a function of vari-
able speeds of the band, but this method of distribution in
which the nozzle is subjected to a to-and-fro movement from
one edge of ~he band to the other, results in a non-uniform
` distribution of the product over the whole width of the band,
due to the differences in speeds of the nozzle above the vari-
ous points of the travelling band.
In addition, this alternating method of distribution
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presents mechanical problems for the manufacture of sheets at
high speed.
The object of the present invention is to obtain at
high speed a uniform deposit on a wide movlng band of a liquid,
pasty or fibrous-texture product, without necessitating the
provision of complicated mechanical devices.
To this end, the present invention contemplates a
method of distribukion of the produc-t, in which there i5
employed an endless deformable band which is caused to be
lakerally deformed over a portion of its -travel and to follow
all or part of a regulated surface or a surface of revolution
having its yenera-tor lines parallel to the direction of
movement of the band, this method being characterized in that
the product to be distributed is deposited on the ~and by
projection under pressure from at least one jet of product
from a source located close to the centre of -the directrix of
the surface of revolution. In this way, all the points of the
band are fed in identically the same manner from this source.
It will be unders-tood that the flow-rate o~ the
~0 source will be a function of the speed of ejection of the
product, and may therefore be easily regulated. In addition,
the effect of projection will produce an ideal dispersion of
the fibres in the produc-t and in conse~uence a uniform distri-
bution of the fibres on the band.
In order to pass into the regulated surface, the
deformable band is curved and provisionally takes the shape of
this surface, which serves as a guide. The shape of this
surface has a certain symmetry, all the points of the band
being located substantially at the same distance from t;he
.
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source of distribution, which enables a continuous and uniform
distribution of the product to be obtained.
The jet of the product may have the form of a radial
beam, and in -this case, the point source will be causPd to
rotate on itself in order tha-t the beam can sweep over the
entire width of the band.
According to an alternative form, the jet may have
the shape of a peripheral layer extending from the axis of the
regulated surface over the whole transverse section of -this
surface, and in this case the source may be fixed, if so
required.
In the case of use of a single band, at the outlet
of the said regulated surface, the sheet or fabric formed may
be slit along the edges of the band and will accompany the
straightening action of this latter back to the flat form,
before being separated from the band. However, in the case of
a sheet of sufficient strength, this may also be extracted in
the form of a cylindrical sheath. It is then separated from
the carrier band i~mediately after i-ts outlet from the surface
of revolution. The cylinder obtained may -then be cut to
lengths and then each section can be cut along a generator
line if it is desired to obtain flat sheets.
Furthermore, in order to limit the deformation
stresses in the carrier band and to reduce the final width of
; the sheet, use may advantageously be made of two iden-tical
bands travelling at the same speed and located face to face in
the interior of the surface of revolution, -the said bands
extending over all or part of this surface. In this case, the
sheet extracted is cut along the edges of the -two bands, thus
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forming two separate sheets, each of which may be conveyed by
the band in contact with which it has been formed, or alterna- :
tively they may be transferred on to a single band.
The invention also relates to a device for the con-
tinuous manufacture, especially at high speed, of uniform
sheets or fabrics, from a li~uid, pasty or fibrous-texture
product. This device comprises at least one deformable
endless band supported, guided and driven by appropriate means,
and a chamber with an internal surface of revolution in which
khe band passes while being deformed, the said device further . .
comprising means ~or dis-tribution by projection of the product,
having at least one projection orifice di.rected towards -the
surface of the band, the axis of these means being arranged
close to the axis of the said chamber, or coincident with this
latter. These distribution means may have a diameter in the :
vicinity of that of the chamber.
During the part of the travel in which the product
is distributed - that is to say in the interior of the chc~mber
- this device permits the creation of a uniform distribution
about an axis and the supply to all the points of the band
under the same conditions, which is necessary in order to
obtain a uniform distribution of the product.
According to a simple form of construction, the
chamber of the device is constituted by a cylinder, and there
:. is employed a single band having a width substantially equal
~ to the circumference of the internal wall of the cylinder.
; According to an alternative form, the device may be
provided with two identical bands of width substantially equal
to the half-circumference of the cylinder.
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According to another alternative form, the internal
surface of the chamber has a director curve with a large
radius of curvature, defining a small deformation of a number
of bands travelling through the said chamber.
The projection nozzle or nozzles with which the
device is provided in a first form of construction, have at ~
least one ejection orifice of small section capable of ~ ;
emitting a radial point jet and the nozzle is driven in ro-ta-
tion in a continuous manner and at constant speed so as to
permit a sweeping movement over the entire width of the band.
The flow-rate, the speed and/or the ~lirection of rotation of
the nozzle or nozzles -to be regulated wi-th accuracy, these
various parameters determining the value of the emission speed
of the jet and the intersecting arrangements of the pro~ected
systems on the manufactured sheet. ;
In accordance with a second form of construction,
the nozzle or nozzles are provided with ejection orifices of
small section capable of emit-ting a peripheral layer which
forms an annular liquid film of the product to be deposited on
-the band. In this case, the nozzle or nozzles may remain
fixed, if so desired.
The use of nozzles is very advantageous, since in
addition to the advantages already mentioned, they can prefer-
ably be fixed on orientatable means, intended to give the
possibility of varying and regulating the incidences of the
emitted jets.
It is known that the speed of emission of the jet
and its incidence are essential parame-ters whlch determine the
anisotropic characteristics of the sheet or fabric obtained.
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The device according to the inven-tion thus enables these
characteristics to be varied and regulated. Furthermore, the
device according to the invention is usefully equipped with
means for recovering excess quantities of products projected;
these means may simply consist of a receptiacle in the form of ~-
a funnel, in which the edge of the flared side is provided
with a flexible joint coming into con-tact with the deformed
band or the internal surface of the chamber. The excess
product streams along this band or this surface and is Einally
collected by means of the flexible joint, in the receptacle of
funnel shape, from which it is evacuated by a conduit before
being re-cycled.
The invention finally relates to the application of
the method and the device to the manufacture of a sheet of
paper, the product -to be distributed being a paper pulp.
The description which follows below of this latter
application, given by way of example, will enable the princi- ~-
ple and the advantages of the invention to be better under-
stood, reference being made to the accompanying drawings, in
which:
Fig. 1 is a simplified view in perspective of a
device according to the invention;
Fig. 2 shows diagrammatically a test carried out by
means of a cylinder of paper slit along part of its height;
Fig. 3a i5 a diagrammatic section of a chamber
according to the invention, taken along an axial plane;
Fig. 3b shows an alternative form of distr:~utor
intended for mounting in a cham~er according to the invention,
in an enlarged view;
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l~SCI 741
Figs. 4 and 5 show diagrammatically two methods of
extraction of sheets of pap~r formed in the devices according
to the in~ention;
Fig. 6 shows a second alternative form of con-
struction of the supply mechanism for a device according to
the invention.
In Fig. 1 is shown a parallelepiped frame, open on
its front face and carrying rollers 2, 3, 4 and 5, identical
and capable of being driven at equal speecl in rotation about
their own axes, by conventional driving means (not shown).
These rollers 2, 3, ~ and 5 yuide, support and drive an
endless deformable canvas band 6. This band 6 is made up of
`tWQ series of p~rpendicular strands forming flexible meshes.
These elements are capable of being deformed and sliding on
each other, so that the band can be subjected to very consider- -~
able deformation.
In the vertical rising portion, the band passes into
a cylindrical chamber 7, which is fixed to the frame 1, for
example by means of collars such as 8.
As shown in Fig. 3a, this chamber 7 is constituted
by an internal wall 9, filtering and cylindricall and by an
outer wall 10. The circular section of this internal wall 9
has a length equal to the width of the band 6. In contact
with this internal wall 9, the band 6 is deformed and follows
the cylindrical form of this latter, the two edges of the band
coming into contact with each other along a generator line of
this wall. In addition, suction means (not shown) are capable
of acting through a conduit 11 so as to create a depression in
the annular space comprised between the internal wal] 9 and
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the external wall 10.
In addition, the chamber 7 is provided at its base
with a funnel-shaped receptacle 12, extended by a conduit 13.
On the upper edge of this receptacle 12 is fixed a flexible
joint 14 coming closely into contact with the surface 9.
Finally, the chamber 7 is equipped with a nozzle 15
of the type permitting the ejection of a jet of fluid, of a
thermo-plastic material for example, which cools in the form
of a thread. This nozzle, utilized in this case to project
paper pulp, is mounted on conventional orientatable means
shown diagrammatically at 16, for example a ball-joint per-
mitting regulation of the angle of incidence o~ the jet with
respect to the vertical, and provided with any suitable
locking means enabling the ball-joint to be kept locked a~ter
adjustment. In addition, this nozzle may be given a continu-
ous movement of rotation about the axis of the chamber by
means of a driving devlce indicated at 17, and it is supplied
with fluid through a conduit 18. The driving device may be
constituted by a small motor.
It will however be understood that the drive may be
effected by an external motor coupled to a shaft arranged in
the axis of the chamber, the device 17 being then a driving
system, with gears for example.
In order to form a sheet 21 having given anisotropic
characteristics, the speed of travel of the band 6 is regu-
lated, the orientation of the nozzle and the speed of rotation
of this latter are adjusted, together with -the flow-rate of
paper pulp in the conduit 1~, to predetermined values, obtain- !
ed for example by means of charts.
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It should be noted that the ratio of the speed of
rotation of the noz~le 15 to the speed of travel of ~he band 6
should not be less than a certain value, if it is desired to
obtain a sheet having a continuous surface. In the case where
this condition is not observed, there would be formed on the
band a helix of pulp having a more or less large pitchl de-
pending on the value of the above-mantioned ratio.
In an alternative form, Fig. 3b shows a distributor
intended for mounting along the axis of a chamber. This dis-
tributor is constituted by a conduit 22, at the inner extremi-
ty of which is fixed a rod 23. This rod is threaded on its
portion which is ou-tside the conduit 22, so as to permit the
fixing on this portion of a disc 24 having an adjustable
height, and arranged to co-operate wi-th the flared edge of the
conduit 22 in order to regulate the flow-rate and also the
angle of incidence of the emitted jet. To this end, the disc
may be flat, as shown, or it may be incurved.
This distributor thus projects a 1uid screen which
has a symmetry of revolution with respect -to -the axis of -the
chamber and has the advantage that it does not comprise any
moving part.
This device is particularly advantageous in dis-
charging an annular screen of paper pulp which flows in a
uniform stream carried away by the rising band. It will be
noted that the diameter of the annular outlet of the distribu-
tor may be variable and in particular it may be in the vicini-
ty of -the diameter of the chamber. The suction produced -~ ~
through the band 6 and the wall 9 enables the deposi~. of , ~,
fibxes in suspension to be accelerated, and permits the evacu-
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ation of the carrier fluid. The excess quantities of paper
pulp flow over the band 6 and are then recovered at the base
of the chamber 7 in the funnel 12 by means of the flexible
joint 14. -
At the outlet of the chamber 7 (see Fig.l~ the sheet
formed is slit and the band 6 is caused to return to its flat
form by means of the roller 2. This change of shape must obvi
ously not interfere with the distribution of paper pulp on the
band, in particular by creating stresses inside the sheet form-
ed. Fig. 2 makes it easy to see that the stresses developedin the sheet during the course of this change of shape are
entirely negligi~le. This fiyur~ shows a cylinder 25 of paper
slit from a point 26 al~ng one of its generator lines. It is
found that the slit cylinder opens naturally and tends to give ~ -
a flat band of paper at a very short distance from the point 26.
In order that the stresses developed in the sheet
conveyed on the band 6 may be negligible, it is therefore only
necessary to place the roller 2 in such manner that it imposes
on the band 6 a change of shape which would be natural for a
sheet alone. The association of Figs. 1 and 2 shows that this
condition is verified for the device shown in Fig. 1.
After its passage over the roller 2, the sheet of
paper 21 is separated from the band 6 by a press 27, and is
directed towards the conventional devices which will subject
it to all the necessaxy subsequent treatments.
The advantage of such a device is clear which,
during the distribution, creates symmetry of revolution around
the distributor and, by supplying all points of the band under
the same conditions, makes it possible to obtain, even at high
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speed, a perfectly uniform distribution of the paper pulp. In
addition, a dPvice of this ~ind provides the possibility of ob-
taining a sheet having the desired anisotropic characteristics.
~ umerous alternative forms may be envisaged for the
device described, which obviously do not depart from the scope
of the invention. For example, the device may comprise two
bands 28 and 29 in Fig. 4, 30 and 31 in Fig. 5, each having a
width e~ual to the length of the half-circumference of -the
cylindrical chamber. This arrangement makes it possible to
reduce the deformation of the bands employed. At its outlet
from the chamber, the sheet formed is cut along the edges of
the two bands, thus giving two separate sheets 32 and 33 in
Fig. 4, 34 and 35 in Fig. 5. In the device shown in Fig. 4,
each of the sheets is conveyed by the band on which it has
been formed, before being separated from this band. On the
other hand, in the device of Fig. 5, the sheet 35 formed on
the band 31 is transferred by the press 36 to the band 30, on
top of the sheet 34.
Devices may also be envisaged which comprise a
ZO number of multiple bands, or which are provided with chambers
having varied interior surfaces (sur~ace with elliptical di-
rectrices, etc.~ without departing from the scope of -the
invention.
Furthermore, in connection with Fig. 3b, there has
been described an annular distributor of fairly small diameter.
It would of course be possible to contemplate distributors
having a fixed or adjustable diameter which could vary between
a point size and the dimensions of -the formation chamber. In
addition, the annular sheet of fluid passing out of -the dis-
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tributor could be given a movement of rotation about its axis.
On the other hand, although there has been shown in
the drawings a device in which the nozzle 15 or the distribu-
tor 24 comprise a single orifice or projection slot, it will
be understood that it would be possible to provide a nozzle or
a distrihutor with a number of orifices without departing from
the scope of the invention.
Similarly, in an alternative form, there could be
provided a plurality of nozzles superimposed along a common
vertical shaft, as shown in Fig. 6. In this alternative form,
on an axial shaft 40 is mounted a first tube 41, -terminating
at its upper portion in a rotating head 42 provided with
curved radial arms 43. These arms 43 have a centra:L channel
44 communicating with the interior 45 of the tube 41 into
which is sent a first flow of pulp under pressure in the di-
rection of the arrows 46.
The tube 41 is surrounded by a second tube 49 pro-
vided with a head 48 having identically the same structure as
the head 42, and into which is sent a second flow of pulp 47.
The free extremity of each of the rotating arms 43 is
open towards the exterior, for example in the form of a verti-
cal slot in order to permit the evacuation of the pulp on to
the band 50 passing through the chamber 51, which is also pro-
vided at its lower portion with a recovery receptable shown
diagrammatically at 5Z and similar to the funnel 12 of Fig. 3a.
Rotation of the revolving heads 42 and 48 may be
effected by driving in rotation the central shaft 40 by an
external motor (not shown), and in this case the shaft 40 will
be coupled for rotation to the heads 42 and 48 by any appropri-
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ate couplings. T~e rotation of the heads could be effected in
opposite directions the arms of one of the heads being orient-
ed in the opposite direction to the arms of the other head.
It will however be understood that the structure
described may operate by reaction like a rotating garden spray,
the heads 42 and 48 rotating under the effect of the pressure
of the pulp. In this case, the shaft 40 will be fixed and the
heads 42 and 48 would be freely mounted on this shaft, thereby
avoiding the use of any source of motive power for the rota-
tion of the heads 42 and 48.
In addition, the angle of incidence of the jetsemitted by the arms ~3 may be easily adjus-ted if these arms
are mounted so as to be able to turn in the heads ~2 and ~8,
the arms being maintained in the inclined position desired by
an~ suitable locking means~
The above arrangement may be particularly advan-
tageous when it is desired to distribute in two stages the
product intended to form the sheet. Similarly, it will be
possible to utilize streams of pulp 46 and ~7 of different
natures. In this latter case, the filtration chamber 50 will
preferably be constituted by two superimposed units identical
to the chamber 10, as shown in Fig. 6, and each provided with
an evacuation pipe for the re-cycling of the liquid extracted
from the device.
It will of course be understood that the invention
is not restricted to the terms of the foregoing description but
that on the contrary it comprises all the alternative forms
within the scope of those skilled in the art.
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