A FORMING HEAD FOR DRY FORMING A FIBROUS WEB

TETE DE FORMATION POUR LA FORMATION A SEC D'UNE NAPPE FIBREUSE

English Abstract

A forming head for dry forming a fibrous
web The invention relates to a forming head (1,25) for dry
forming a fibrous web, which forming head is positioned above
a forming wire opposite a suction unit. The forming head
(1,25) is divided into at least two independent interconnected
distribution units (2,3,4,5,26,27,28,29,30,31) each of
which comprises at least one revolving roller (11,12,13,
14,15,16,17,18,19,32,33,34,35,36,37,38,39,40,41) provided
with protruding spikes (12). By dividing the forming head
(1,25) into a plurality of interconnected distribution units
(2,3,4,5,26,27,28,29,30,31), a more efficient disintegration
of agglomerates, shadows and/or lumps in the fibre material
is achieved compared to the known forming heads, thereby
ensuring a more homogenous final product.

French Abstract

L'invention porte sur une tête de formation permettant de former à sec une nappe fibreuse. Selon l'invention, une tête de formation (1, 25) permet la formation à sec d'une nappe fibreuse, ladite tête de formation étant positionnée au-dessus d'une toile de formation à l'opposé d'une unité d'aspiration. La tête de formation (1, 25) est divisée en au moins deux unités de distribution indépendantes et interconnectées (2,3,4,5,26,27,28,29,30,31), chacune desdites unités comportant au moins un cylindre rotatif (11,12,13, 14,15,16,17,18,19,32,33,34,35,36,37,38,39,40,41) pourvu de pointes protubérantes (12). En divisant la tête de formation (1, 25) en une pluralité d'unités de distribution interconnectées (2, 3, 4, 5, 26, 27, 28, 29, 30, 31), on obtient une désintégration plus efficace des agglomérats, des amas et/ou des bosses dans le matériau fibreux par rapport au résultat obtenu avec les têtes de formations déjà connues, ce qui garantit ainsi un produit final plus homogène.

Claims

1
Claims
1. A forming head (1, 25) for dry forming a fibrous web, the
forming head (1,25) being positioned above a forming wire
(8) opposite a suction unit (7), characterized in that
the forming head (1,25) is divided into at least two
distribution units (2,3,4,5,26,27,28,29,30,31) detachable
mounted in the forming head (1,25), the at least two
distribution units is arranged one of top of the other
and each distribution unit comprises at least one
revolving roller (11,12,13,14,15,16,17,18,19,32,33,34,35,
36,37,38,39,40,41) provided with protruding spikes (12).
2. A forming head (1,25) according to claim 1, characterized
in, that the distribution units, in the forming head is in
communication with each other such that the upper
distribution unit(s) (2) can pass fibrous material to the
underlying distribution unit (s) (3,4,5).
3. A forming head (1,25) according to claim 1 or 2,
characterized in that the spikes (12) on the at least one
revolving roller
(11,12,13,14,15,16,17,18,19,32,33,34,35,36,37,38,
39,40,41) in at least one of the distribution units
(2,3,4,5,26,27,28,29,30,31) covers between about 30% to
about 80%, preferably about 65% of the sectional area of
the distribution units (2,3,4,5,26,27,28,29,30,31) seen
in relation to the forming wire (8).
4. A forming head (1,25) according to claim 1 - 3,
characterized in that the spikes (12) on the at least one
revolving roller (11,12,13,14,15,16,17,18,19,32,33,34,35,
36,37,38,39,40,41) in at least one of the distribution
units (2,3,4,5,26,27,28,29,30,31) substantially cover the
entire sectional area of the distribution units

2
(2,3,4,5,26,27,28,29,30,31) seen in relation to the
forming wire (8).
5. A forming head (1,25) according to any of the claims 1-
4, characterized in that at least one distribution unit
(2,3,4,5,26,27,28,29,30,31) has the same or a smaller
horizontal cross section than the underlying distribution
unit (2,3,4,5,26,27,28,29,30,31).
6. A forming head (1,25) according to any of the claims 1 -
5, characterized in that the at least one roller
(11,12,13,14,15,16,17,18,19,32,33,34,35,36,37,38,39,40,41)
in at least one of the distribution unit
(2,3,4,5,26,27,28,29,30,31) are detachable mounted.
7. A forming head (1,25) according to any of the claims 1 -
6, characterized in that at least one revolving roller
(11,12,13,14,15,15,17,18,19,32,33,34,35,36,37,38,39,40,41)
have a different dimension and/or length than the
remaining revolving rollers in a distribution step.
8. A forming head (1,25) according to any of the claims 1 -
7, characterized in that the forming head (1,25) is
provided with a bottom having a pluralities of openings.
9. A forming head (1,25) according to claim 8, characterised
in, that that bottom is a grid having a plurality of
detachable grid elements.
10.A forming head (1,25) according to any of the claims 1 -
9, characterized in that the at least one roller
(11,12,13,14,15,16,17,18,19,32,33,34,35,35,37,38,39,40,41)
in at least one distribution unit (2,3,4,5,
26,27,28,29,30,31), is placed with the longitudinal axes
oriented substantially perpendicularly to the moving
direction of the forming wire (8).

3
11.A forming head (1,25) according to any of the claims 1 -
10, characterized in that the rollers (11,12,13,14,15,16,
17,18,19) in at least one distribution unit
(2,3,4,5,26,27,28,29,30,31), is placed with their
longitudinal axes in the same or in a different
orientation in relation to the rollers
(11,12,13,14,15,16,17,18,19,32,33,34,35,36,37,38,39,40,41)
in one of the other distribution units (2,3,4,5,
26,27,28,29,30,31).
12.A forming head (1,25) according to any of the claims 1 -
11, characterized in that the rollers (11,12,13,14,15,16,
17,18,19) in each distribution unit (2,3,4,5,26,27,
28,29,30,31) are adapted for being rotated around their
longitudinal axes with the same or different speed of
rotations.
13.A forming head (1,25) according to any of the claims 1 -
12, characterized in that the spikes (12) are distributed
evenly along the circumference of the roller
(11,12,13,14,15,16,17,18,19,32,33,34,35,36,37,38,39,40,41).
14.A forming head (1,25) according to any of the claims 1 -
13, characterized in that the spikes (12) in at least one
distribution unit (2,3,4,5,26,27,28,29,30,31), in the
longitudinal direction of the roller (11,12,13,14,
15,16,17,18,19,32,33,34,35,36,37,38,39,40,41), are spaced,
which allow the passage in-between for corresponding
Spikes (12) on an adjacent roller (11,12,13,14,15,
16,17,18,19,32,33,34,35,36,37,38,39,40,41).
15.A forming head (1,25) according to any of the claims 1-
14, characterized in that the spikes (12) on the rollers
(11,12,13,14,15,16,17,18,19,32,33,34,35,36,37,38,39,40,41)
are made of a flexible material.

4
16.A forming head (1,25) according to claim 1, characterized
in, that the forming head comprises four distribution
units (2,3,4,5,26,27,28,29,30,31), placed in succession,
starting from the distribution unit farthest from the
forming wire, wherein
- the first distribution unit (2) comprises one revolving
roller (11),
- the second, distribution unit (3) comprises two revolving
rollers (12,13),
- the third distribution unit (4) comprises one revolving
roller (14),
- the forth distribution unit (5) comprises a plurality of
revolving roller arranged in a substantially horizontal
plane (15,16,17,18,19).
17.A forming head (1,25) according to claim 16,
characterized in that the spikes (12) on the revolving
rollers (11,12,13,15,16,17,18,19) in the first, second
and forth distribution unit (2,3,5) substantially cover
the entire sectional area of the respective distribution
units when seen in a mainly horizontal plane.
18.A plant for producing a fibrous web characterised in,
that the plant comprises a forming head (1,25) according
to any of the claims 1-17.
19.A method for dry-producing a fibrous web, using the
forming head (1,25) according to any of the claims 1 -
17, and wherein the at least two distribution units is
detachable mounted in the forming head (1,25) and
arranged one of top of the other characterized in that
fibrous material is added to the distribution unit (2, 26)
farthest from the forming wire for processing in the
forming head (1,25),

- the fibrous material passed from one distribution unit to
the underlying distribution unit(s) (3,4,5,27,28,29,30,31)
and
- that the fibrous material is laid on the forming wire (8)
for forming the fibrous web.
20. A method according to claim 19, wherein the at least one
distribution unit (2,3,4,5,26,27,28,29,30,31) is removed
from the forming head (1,25), and a different
distribution unit (2,3,4,5,26,27,28,29,30,31) is inserted
instead.

Description

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A forming head for dry forming a fibrous web
The present invention relates to a forming head for dry forming
a fibrous web, the forming head being positioned above a
forming wire opposite a suction unit. The present invention
also relates to a method of using said forming head.
Various forming head of this type are known, for instance from
European Patent Application 0159618. This application describes
a forming head provided with a bottom net or sieve having a
plurality of openings. In order to ensure the passage of the
fibres through the bottom of the forming box it is suggested to
use wings, rollers or other scraping or brushing devices, which
in an active manner removes fibres from the sieve at the bottom
of the forming head. A suction unit is provided underneath the
forming wire for drawing the fibres through the bottom and onto
the forming wire. Although such mechanical devices do give an
increase in the capacity, the obtained increases are not
satisfactory and attempts have been made through many years to
increase the capacity further.
The size of the openings in the mesh or sieve in the bottom of
the forming box is decided by the fibres, which are to be
distributed on the forming wire. This is particularly relevant
in relation to the use of cellulose fibres in the manufacture
of paper products including absorbing products, such as
napkins. Thus, there has been a limitation in the length of the
fibres used.
In an attempt to overcome the problem with fibre length WO
99/36623 describes a forming head with an open bottom, i.e.
without a bottom mesh or sieve. The distribution of fibres is
carried out by a plurality of revolving spike rollers. Said
spikes are arranged to partly hold the fibres back against the
effect from the suction of the underlying suction unit. The
cloud of fibres which is formed inside the forming head of

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single fibres, which are slit up and mixed in the air stream,
are transferred down onto the underlying wire by the
application of the revolving spike rollers. This increases the
capacity of the forming apparatus significantly. However, the
inventor has discovered that agglomerates of fibres may pass
the spike rollers without being torn sufficiently apart by the
spikes, resulting in an uneven distribution of fibres on the
forming wire and therefore in an inhomogeneous final product.
Another problem with the known forming heads is that they are
extremely expensive. Therefore, the manufactures prefer to use
one or more forming heads which can be used for the production
of many different webs, instead of using a forming head having
a design which is optimal for the production of a specific web.
Thus the forming head conventionally used is not specifically
designed for a given product, resulting in a web having a lower
quality than desired.
Thus there is a need for a forming head, which is capable of
meeting the desired optimal production requirements without
impairing the quality of any of the resultant webs.
It is therefore a first aspect of the present invention to
provide a modular forming head, which is strong and which
comprises a number of distribution units which can be readily
assembled into a complete forming head and allow greater
control and adjustment between adjacent distribution units.
It is a second aspect according to the present invention to
provide a forming head which ensures that agglomerates, shadows
and/or lumps of fibres are torn apart to a higher degree than
hitherto known.
It is a third aspect according to the present invention to
provide a forming head according to the present invention,
which ensures an even distribution of fibres on the forming

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wire in a dry-forming apparatus without compromising the
capacity of the fibre distributor.
It is a fourth aspect according to the present invention to
provide a forming head which is reliable in operation and which
allows for longer time between overhauls or maintenance.
It is a fifth aspect according to the present invention to
provide a forming head having spikes which are more resistant
to breakings than hitherto known.
It is a sixth aspect according to the present invention to
provide a forming head capable of easily being adapted to
different fibre types and fibre length.
It is a seventh aspect according the preset invention to
provide a forming head capable of forming different webs and/or
mats without compromising the capacity of the fibre
distributor.
This is achieved according to the present invention in that the
forming head is divided into a plurality of independent and
interconnected distribution units each of which comprises at
least one revolving roller, which are provided with protruding
spikes.
As the interconnected distribution units are detachable mounted
in the forming head, it is ensured that the forming head is a
modular forming head capable of being adapted and modified in
order to meet the production requirements of many different
webs and at the same time obtain a high quality of manufacture
as each distribution unit can be individually and optimally
designed to the material used and the desired final product.
The modular forming head according to the present invention
results in a system having a number of different individual

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distribution units, which readily and arbitrarily can be
assembled into a complete forming head which allow greater
control and adjustment between adjacent distribution units than
known until now.
Thus, the present invention provides a forming head that
simplify installation and assembly of said forming head, and
enable users to arbitrarily add and/or adjust internal
components. The different distribution units of the forming
head according to the invention may furthermore be designed at
the customer's demands.
The different components, distribution units and revolving
rollers may be delivered to and assembled at the production
site, for stand alone use or may be attached to structural
frame elements to provide a forming head that is integrated
with other relevant elements of the production plant.
Installers and/or end users may also modify the configuration
and/or location of the different distribution units and its
components as desired.
The forming head according to the invention is formed from a
plurality of distribution units assembled by way of connector
elements. Preferably connector elements comprise a bolt-type
member inserted into holes in the walls and are fixed with nuts
however other connector elements known to the person skilled in
the art is also contemplated in the present invention.
A forming head according to the invention can therefore be
constructed to be able to arbitrarily handle long fibres and/or
particles and/or short fibres.
Conventional forming heads for manufacturing an air laid web
are always designed specifically to meet the requirements of
the resulting web using the desired fibers, and if e.g. the a

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different fiber length is requested said forming head is not
capable of meeting the requirements of said fibres. Thus, the
use of conventional forming heads is limited to a specific
application. Using the forming head according to the present
5 invention solves this problem as each distribution unit is
designed to be detachably secured and replaceable. When a user
wishes to manufacture a different product using different
fibers or simply different conditions are needed in the forming
head in order to ensure that the web has the desired
properties, the user simply replaces, removes or adds one or
more of the distribution units with one or more different
distribution units depending on the conditions and
requirements.
By providing a forming head according to the present invention
which comprises a number of distribution units it is ensured
that the distribution units readily can be assembled into a
complete forming head meeting the optimal production conditions
needed for the resultant web. Thus, each distribution unit is a
"plug and go" unit, which can be removed and exchanged, swiftly
by hand, replaced by another unit or simply removed or added
from the forming head.
The distribution unit(s) can also be constructed to meet
specific and unique production requirements. Such requirements
could e.g. be related to the final product, the fibre material
used or the airflow supplied in the forming head. In this
respect each distribution unit can be designed optimally,
ensuring that the specific unit is best suited for distributing
and mixing the fibres.
As an example can be mentioned that one of the distribution
units can be designed to give a very high impact force to the
fibre material supplied to the unit, whereas another
distribution unit can be designed to ensure a high degree of
mixing of the fibre material supplied to the forming head.

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Thus, the forming head allows greater control and adjustment
between adjacent distribution units than known until now.
Furthermore, by having a forming head that comprises at least
two independent distribution units, the inventor has
surprisingly found that a more efficient disintegration of
fibres is achieved compared to the known forming heads.
This is due to the fact that the disintegration of
agglomerates, shadows and/or lumps of fibrous material are
influenced by strokes from spikes on the revolving rollers.
When the spikes on the revolving roller impact with e.g. the
agglomerates the impact force will ensure that said
agglomerates are disintegrated. By having more than one
distribution step it has surprisingly been found that
agglomerates, shadows and/or lumps that are not disintegrated
in the first distribution step will be disintegrated in the
underlying unit.
Using the forming head according to the present invention will
thereby not only ensure, that all agglomerates, shadows and/or
lumps in the fibrous material will be removed but also that the
fibres will completely opened and separated.
The present invention therefore provides the possibility of
producing uniform webs at higher speeds than heretofore
possible and/or to improve the uniformity of webs made at
existing speeds. This is assumed that the very high degree of
separation caused by the different distribution steps improves
the mixing of fibres in the forming head to give these improved
results.
When a forming head according to the present invention is
applied in a dry-forming apparatus, it has furthermore been
possible to form a fibrous product, where problems are avoided

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with the variation of the thickness over the width of the
product.
As used herein, the term "distribution unit" refers to a
distribution unit, which is capable of standing alone i.e.
function as a forming head without the control or influence of
another distribution unit.
Thus, the forming head according to the invention does not only
provide a more efficient opening and disintegration of fibres
than hitherto known, but will also ensure that that fibre lumps
or oversized fibres are prevented from being laid down on the
forming wire and that the fibres are mixed homogenously before
they are placed on the forming wire. The forming head according
to the invention thereby achieves an even distribution of
fibres on the forming wire without reducing the capacity of the
fibre distributor.
In order to achieve further disintegration of the fibres and
thereby promote a more even distribution, the at least one
revolving roller with belong spikes in at least one of the
distribution units can advantageously cover the entire
sectional area of the distribution unit when seen in a mainly
horizontal plane. Thereby it is ensured that the fibres are
partly retained in the distribution unit whereby the remaining
agglomerates, shadows and/or lumps will be returned to the
distribution unit in question, providing that e.g. the
agglomerates is comminuted and disintegrated rather than being
sucked down to the forming wire by the suction unit.
This is preferably the distribution unit placed just above the
forming wire, but could in an alternative embodiment be any of
the distribution unit or several of the distribution units.
However, in a preferred embodiment the sectional area of at
least one of the distribution units is only covered partly by

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the at least one revolving roller with belonging spikes. The
inventors of the present invention have surprisingly discovered
that this ensures that the air circulation and air direction is
reverse providing a more even and homogenous distribution of
fibres compared to a forming head where the sectional area of
the distribution units are completely covered by the revolving
rollers. It is especially preferred if the percentage of the
sectional area covered by revolving rollers in said
distribution unit is between about 30% to about 80%, preferably
about 65%.
In order to obtain that only a part of the sectional area of
the distribution unit(s) is covered by the at least one
revolving rollers it is possible simply to place fewer
revolving rollers in the distribution unit and/or by regulating
the dimension of the spikes on the revolving rollers. However,
it is also possible either alone or in combination to regulate
the dimension and/or length of the revolving rollers.
The person skilled in the art will based on the material used
and the final product in combination with the information
provided in the present application be able to find the optimal
requirements for the different distribution units and thereby
the forming head according to the invention.
In a preferred embodiment according to the present invention
the at least one distribution unit comprises a plurality of
revolving roller arranged in a substantially horizontal plane.
As the fibrous material in this respect will be forced to pass
the revolving rollers, it is ensured that the fibres are
symmetrically laid down on the forming wire, forming a final
product with a homogeneous thickness over the width of the
forming wire.
All revolving rollers in a distribution unit are preferably
driven by a single engine and a synchronous transmission belt.

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Thereby is obtained the beneficial effect that the revolving
rollers can be placed so that the outer ends of the spikes
describe circles that overlap each other e.g. meshes like
toothed gear. Such an embodiment has the advantage that the
revolving rollers can be placed closer to each other, whereby
the fibres can be influenced by more than one spike at a time.
This will provide a higher impact force on the agglomerates,
lumps and/or shadows, enabling a better disintegration of the
fibrous material. Furthermore, when the outer ends of the
spikes are transferred in-between each other, it becomes
possible to manufacture a fibrous tissue using very short
fibres, for instance with lengths down to 3 mm. Hereby it
becomes possible to achieve a product with a very homogeneous
profile in the sectional direction as well as in the
longitudinal direction.
The closer the spikes are placed to each other on the revolving
rollers, the more efficient will the spikes return
agglomerates, lumps and/or shadows to the distribution unit. In
this manner the fibre clumps or clusters of fibres are retained
by the spike rollers and separated or disintegrated in a
graduated fashion as these retained fibres are returned by the
spikes to the distribution unit rather than being sucked down
to the forming wire by the suction unit.
Alternatively the revolving rollers can be placed so that the
outer ends of the spikes describe circles that do not overlap
each other. This is especially advantageously when the forming
head according to the present invention handles long fibres,
for instance with a length of 60 mm or more as the circles
which define the outer ends of the spikes substantially just
touch each other or are a little shifted from each other. In
this respect the spikes on one revolving rollers are preferably
placed very close to the spikes on a neighbouring roller, e.g.
2 mm.

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Furthermore, it is possible to vary the intensity of the spikes
both in the axial direction and the circumference of the
revolving roller. By means of these parameters, the placement
of the spikes in relation to spikes on a neighbouring revolving
5 roller, the number of revolutions for the rollers and the air
stream it is possible to adjust the capacity of the forming
head according to the invention.
The spikes can according to one embodiment according to present
10 invention be made of a partly or completely flexible material.
In this way it is ensured, that if the spikes touches or hits
each other or the wall of the forming head, the spikes will not
break or snap. This will ensure that the forming head is more
reliable in operation and requires lesser maintenance than the
known forming heads using non-flexible spikes. Such flexible or
partly flexible spikes can e.g. be in the form of bristles or
brushes.
Alternatively, the spikes can be made of a non-flexible
material. Such spikes will provide a higher force of impact,
which is preferred for some kinds of fibre material. Using a
non-flexible material for the spikes will thereby ensure that
especially recalcitrant agglomerates, lumps and/or shadows are
disintegrated.
In any case, the longer the spikes the harder the impact on the
fibrous material and the more efficient is the separation of
the agglomerates.
In another preferred embodiment according to the present
invention the at least one roller in at least one of the
distribution unit are detachable mounted. Thereby is it
possible to arbitrarily adjust e.g. the closeness of the spikes
on the revolving rollers, the length of the spikes and/or the
material the spikes are made of simply by replacing, removing

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or adding one or more of the revolving rollers in a
distribution unit.
The adjustment can also be effected by mounting the rollers
mutually displaceable in a substantially horizontal plane,
whereby it is possible to establish gabs, which allow a bigger
amount of fibre material to pass within a given period of time.
Alternatively the revolving rollers in a distribution unit can
have different lengths and/or dimensions.
The forming head can advantageously be provided with a bottom
with a plurality of openings. This bottom can preferably be
placed in the distribution step closest to the forming wire,
but can within the scope of protection be placed in all, some
or none of the distributions units, depending on the used
fibrous material and the final product.
If for instance long fibres are to be handled, it is preferred
that there is not placed a fixed bottom at the distribution
step(s). However, if smaller fibres or particles are to be
distributed via the forming head, one or more distribution
steps can advantageously be provided with a fixed bottom.
The suction unit placed beneath the forming wire, which
preferably is a vacuum unit, will influence the small particles
and/or fibres to a higher degree than the longer fibres. The
fixed bottom will prevent the small fibres and/or particles
from being sucked directly through the revolving rollers and
onto the forming wire and will therefore contribute to ensure
that products comprising small fibres and/or particles also are
homogenous.
The fixed bottom can preferably be in the form of a sieve, net
or a grid arranged for placing the fibres and/or particles on
the forming wire. In order to ensure the passage of the fibres
and/ or particles through the bottom of the forming head the

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bottom can comprise wings, rollers or other scraping or
brushing devices, which in an active manner removes fibres from
the bottom.
The size of the openings in the mesh or sieve at the bottom of
the forming box depends upon the characteristics of the fibres
and/ particles, which are to be distributed on the forming wire
and on the desired product. This is particularly relevant in
relation to the use of cellulose fibres in the manufacture of
paper products including absorbing products, such as napkins.
When the bottom is in the form of a grid having a plurality of
detachable grid elements, the bottom can be easily changed to
in order not only to adjust and/or change the capacity of the
forming head, but also in order to change the transferring rate
of the fibres to the forming wire. In this respect the bottom
can contribute in optimising the final product.
The rollers can preferably be placed either horizontally or
vertically whereby the spikes will rotate in a vertical plane
and a horizontal plane, respectively. This is preferred because
of the symmetrically laying down of fibres so that a tissue
with homogeneous thickness is formed over the width of the
forming box.
In order to arrange the forming head with horizontally oriented
rollers for handling of fibres with various abilities it is
possible to provide several layer of rollers in each
distribution unit. The rollers in each layer can be placed on a
row with their longitudinal axis oriented parallel or
orthogonal on the movement direction of the forming wire. The
longitudinal axis of the rollers can, however, also be oriented
in the direction parallel with the movement direction of the
forming wire.

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According to the invention is has been shown possible to form a
fibrous product, where problems are avoided with the variation
of the thickness over the width of the product formed on the
forming wire. It is anticipated that this surprising
homogeneity of the thickness of the created product over the
width of the product is due to fact that the rotation of the
spike rollers leads the fibres directly down against the
forming wire in the direction orthogonally on the surface of
the forming wire. Thus in an advantageously embodiment the
rollers in each distribution unit are adapted for being rotated
around their longitudinal axes with the same rate of rotations,
e.g. within an interval of between 200 and 5000 rpm, preferably
about 2000-3000 rpm.
However, the rollers can in a different embodiment be adapted
for having different rates of rotation in the different
distribution steps or simply within a single distribution unit.
By allowing the rotational speed to be adjustable, each
distribution unit can be made to work at an optimum, even if
the unit at different times is supplied with different amounts
of materials. In this respect it is also possible to design
each distribution steps for materials having special physical
properties.
As previously mentioned the spikes on each revolving roller can
be distributed both along the longitudinal axis of the roller,
and along the circumference of the roller. It is preferred that
said distribution is evenly in both directions in order to
ensure a homogenous distribution to the forming wire.
It is also possible to use very varying dimensions and
revolving rates. It is, however, preferred that the axial
distance between the spikes is between 3 and 20 mm, and that
the thickness of the spikes is between 0,5 and 10 mm. The
length of the spikes will be between 5 and 200 mm, preferably
about 100 mm.

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Within the scope of the present invention it is also possible
to use rates of rotation, lengths of spike and thickness of
spike, which lie outside these intervals. By varying the length
and the thickness of the roller and spikes it is likewise
possible to handle long fibres without the risk that they spin
into each other. That is, it will be possible to handle the
long fibres and get these down on the forming wire as
individual fibres, without being spun into each other.
In order to manufacture final products of very short fibres,
i.e. having length of around 2-4 mm, the outer ends of the
rollers with the protruding spikes are spaced in order to allow
the passage in-between for corresponding spikes on an adjacent
roller, e.g. the spikes meshes like a toothed wheel. Hereby it
becomes possible to achieve a very homogeneous product with a
very homogeneous profile in the sectional direction as well as
in the longitudinal direction. It is also possible to handle
the short fibres, as the fibres to a higher degree will be
retained in the distribution unit, preventing the fibres from
falling directly onto the forming wire.
The present application the term spikes will cover an
embodiment with largely thread-formed spikes. However, the
issue will also cover plate-formed elements, which also can be
designated as wings. Such plate-formed wings will primarily be
formed with the expanse placed in a plane orthogonally on the
rotation axis of the axle. Alternatively the plates can be
formed with a slope or be formed like propellers to bring about
an upwards or downwards directed action on the fibre cloud. To
facilitate the passage of air to the forming head when wing-
formed spikes are applied, the wings can be provided with
holes. Such holes can facilitate the passage of air. By
appropriate choice of revolving speed and form of holes in the
rollers the passage of fibres to such holes can be hindered or
limited.

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In an especially advantageously embodiment according to the
invention the forming head comprises four distribution units,
placed in succession starting from the distribution unit
5 farthest from the forming wire. It has surprisingly been found
that when the first distribution unit comprises one revolving
roller, the second distribution unit comprises two revolving
rollers, the third distribution unit comprises one revolving
roller, and the forth distribution unit comprises a plurality
10 of revolving roller arranged in a substantially horizontal
plane, the fibrous material will be completely opened and free
from lumps and shadows which again ensures a very even
distribution of the fibres on the forming wire.
15 The top distribution unit are preferably arranged to be able to
transfer a relatively higher impact to the fibrous material.
Thus it has been found that a single revolving roller having
long spikes of e.g. between 50 and 130 mm in length is
preferred. In this respect the first distribution unit can have
the same or a smaller horizontal cross section than the
underlying distribution unit(s). The inventors have shown that
a forming head having said construction provides a decidedly
beneficial "shower effect" created by the difference in air
fluxuation, that distributes and effectively spreads the fibres
evenly onto the longer underlying distribution unit(s).
The final product may be made from or at least include natural
fibres, such as cellulose fibres, fibres from flax, hemp, jute,
ramie, sisal, cotton, kapok, glass, stone, old newsprint,
elephant grass, sphagnum, seaweed, palm fibres or the like.
These fibres have a certain insulating capacity that may be
useful in many applications.
The product may also be made from or at least include a portion
of synthetic fibres, such as polyamide, polyester, polyacrylic,
polypropylene, bi-component or vermiculite fibres or the like

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16
as well as any kind of granular material. Fibreboards with such
synthetic fibres may be used for providing the fibre product
with certain properties, e.g. absorbent products. Moreover, the
fibres may be pre-treated with a fire retardant or a fire
retardant may be supplied directly in the fibre mixture, which
is blown into the forming box.
Since the forming head according to the present invention is
capable of using very long fibres, it is possible to create a
stable product, although it is manufactured with a big
thickness. This is due to the fact that the long fibres are
capable of forming fibrous bindings over a relatively big layer
of material, e.g. up to 200-400 mm. The bindings can be crispy
hydrogen bindings or elastic bindings, which are established by
means of binding material or a combination hereof.
The forming head according to the invention can therefore be
used to e.g. manufacture isolation mats from synthetic fibres
or natural fibre or mixtures hereof
In this respect the distribution unit closest to the forming
wire can optionally comprise end walls, which can be adjusted
with respect to the heights in relation to the forming wire.
Thereby is achieved the advantage that the thickness of the
final product is not limited to a specific maximum height.
The invention will be described in more detail with reference
to the accompanying drawing, where
Fig. 1 is a schematic perspective view of a forming head
according to one embodiment of the invention;
Fig. 2 shows a schematic side view, partly sectionally, of the
forming head shown in fig. 1,

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Fig. 3 shows a schematic side view, of the forth distribution
unit shown in fig. 1,
Fig. 4 shows a schematic side view, of a different embodiment
of the forth distribution unit in fig. 1, and
Fig 5a shows a schematic side view of a forming head according
to a second embodiment of the invention.
Fig 5b shows the embodiment shown in fig. 5a in a schematic
front view.
In the following fig. 1 - 4 it is assumed by way of example
that the forming head according to the invention comprises four
distribution units. This are of course in no manner intended to
be limiting to the invention, and within the scope of the
present invention the forming head can comprise from two to a
plurality of distributions units.
In fig. 1 a forming head 1 according to a first embodiment of
the invention is shown. The forming head comprises four
independent interconnected distribution units 2, 3, 4 and 5
respectively. Fibres are supplied to the first distribution
unit 2 via an inlet 6. A suction unit 7 is positioned beneath a
forming wire 8, and the forming head is positioned above the
wire. Fibres 9 are air laid on the forming wire 8 to form a web
10 in a dry forming process.
In fig. 1, the forming head is shown with the interior elements
visible in the forth distribution unit 5. However, it is
realized that the housing walls may be made from transparent or
opaque materials.
Inside each distribution unit 2,3,4,5 revolving rollers are
provided with protruding spikes 12.

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In the embodiment shown in fig.1 the first distribution unit 2
comprises one revolving roller 11, the second distribution unit
3 comprises two revolving rollers 12, 13, the third
distribution unit 4 comprises one revolving roller 14, and the
forth distribution unit 5 comprises five revolving rollers 15,
16, 17, 18, 19, placed in a substantially horizontal plane
parallel to the forming wire 8.
The five revolving rollers 15, 16, 17, 18, 19, which are placed
within the forth distribution unit, can be said to make up the
bottom of the forming head wherein three revolving rollers 15,
16, 17 are placed by one side wall of the distribution unit and
two revolving rollers 18, 19 at the opposite side.
It will be evident for the person skilled in the art that the
number of revolving rollers can be adjusted depending on the
desired product and the fibres used.
Engines 20, arranged with the possibility for a variable
revolution rate, drives each revolving roller, ensuring that it
is possible to adjust the revolution rate of the engines
dependent of choice of rollers, spikes and the product, which
is to be formed.
Each of the revolving rollers 11,12,13,14,15,16,17,18,19 has an
axle 21, upon which spikes 12 in form of thread-formed elements
are protruding. The spikes 12 are established with a size and a
mutual distance, which makes it possible to allow for a passage
in-between for corresponding spikes 12 on a neighbouring
revolving roller.
The revolving spike rollers are in the embodiment shown in fig.
1 placed so that the outer ends of the spikes describe circles
that do not overlap each other.

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The fibres 9 are supplied to the forming head 1 via inlets 6.
Said fibres will comprise agglomerates, lumps and/or shadows
and when these comes into contact with the spikes 12, the
agglomerates, lumps and/or shadows will be disintegrated or
shred in order to ensure an even distribution of fibres 9 in
the product 10 formed on the forming wire 8.
This is due to the fact that the disintegration of agglomerates
of a fibrous material are influenced by strokes from spikes on
the revolving rollers, and when e.g. an agglomerate is hit by a
revolving spike the impact force will ensure that the
agglomerate, at least to some extend, will be forced to open
and/or disintegrate.
As this is repeated, not only several times in each
distribution unit, but also in the four distribution units, all
agglomerates, shadows and/or lumps will be removed in order to
ensure an even distribution of fibres 9 in the product 10
formed on the forming wire 8.
The closer the spikes 12 are placed to each other on the
revolving rollers 11,12,13,14,15,16,17,18,19, the more
efficient will the spikes return agglomerates, lumps and/or
shadows to the respective distribution units 2,3,4,5, In this
manner the fibre clumps or clusters of fibres are retained by
the revolving rollers and separated or disintegrated in a
graduated fashion as these retained fibres are returned by the
spikes 12 to the distribution unit rather than being sucked
down to the forming wire 8 or underlying distribution unit by
the suction unit 7.
Fibres are supplied in an airflow to the first distribution
unit 2 via an inlet 6. The airflow can be created by means of
transport blowers, which are linked with pipes that lead to the
distribution unit, but other ways of obtaining the airflow

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known to the person skilled in the art are within the scope of
protection.
In the embodiment shown in fig. 1 the fibres are primarily led
5 in from each side of the first distribution unit 2, but fibres
could also be feed to the distribution unit by means of more
inlet pipes on each side of said distribution unit or to
several of the distribution units. It is hereby possible to
vary the capacity of the forming head by opening and closing
10 the inlet pipes.
As an alternative to the inlet 6 the fibres can be introduced
to the distribution unit in question by blowing them into said
distribution unit. This will ensure, that the fibres have a
15 substantial velocity upon introduction to the unit, which
provides that large concentrations variations throughout the
forming head will be reduced or even eliminated, ensuring a
more uniform distribution of powder to the web.
20 The topmost first distribution unit 2 may or may not have a
detachable lid 23 to allow inspection and maintenance of the
forming head, and to provide the possibility of admitting false
air so that a negative pressure does not build up in the
forming head and obstructs the continuous flow towards the
forming wire obtained by means of the suction unit. Preferably,
the lid 23 has an air inlet opening 24 for admitting the false
air. The opening may be provided in the lid 23 or any other
suitable site on the forming head, e.g. in the axial side of
the first 2 and/or subsequent distribution unit, as well as
more openings may be provided and favourable.
The uniform distribution is furthermore increased as the
revolving rollers retain fibres before they are gradually
sucked down via the vacuum from the suction unit to the forming
wire. In this way the revolving rollers works as a kind of

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21
buffer zone, ensuring, that the fibres do not fall directly
onto the forming wire.
Fibres or other product which are to be part of the final web
could also be are added to several of the distribution steps of
the forming head according to the invention, increasing the
capacity of the forming head.
In this respect the fibre material comprising the agglomerates,
lumps and/or shadows which requires the highest impact force
can be feed to the first distribution step 2, and the fibre
material which requires the lowest impact force to the forth
distribution unit 5.
Fig. 2 shows a schematic side view, partly sectionally, of the
forming head shown in fig. 1. On the right side of the picture
a partial section is shown for schematically illustrating the
revolving rollers 11,12,13,14,15,16,17,18,19 and the left side
of the picture shows the engines 20.
As is seen the first distribution unit 2 and the third
distribution unit 4 both comprises one revolving roller 11, 14
having spikes 12, which covers only about 65% of the sectional
area of the distribution unit. In contrast the second
distribution unit 3 has the two revolving rollers 12, 13, with
spikes that substantially covers the entire area of the
respective distribution units.
The forth distribution unit 5 has five revolving rollers 15,
16, 17, 18, 19, placed in a substantially horizontal plane
parallel to the forming wire 8. These revolving rollers with
belonging spikes will cover the entire bottom of the forth
distribution unit 5, through which the fibre material will be
released to the forming wire. Since the spikes partly will
retain the fibres against the effect from the suction of the
suction unit the cloud of fibres, which has been formed inside

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22
the forming box of single fibres are split up and mixed in the
air stream, are transferred down onto the underlying wire by
application of the revolving spike rollers.
Fig. 3 shows a schematic side view of a forth distribution unit
5, according to the invention wherein the spikes 22 on the
revolving rollers 15,16,17,18,19 are placed so that the outer
ends 23 of the spikes describe circles that do not overlap each
other.
This is especially advantageously when the spikes 22 on the
revolving rollers are not flexible, as an impact between two
revolving and adjacent spikes can cause the spikes to break.
Fig. 4 shows a different embodiment of the forth distribution
unit 5, according to the invention to the invention described,
wherein the spikes 22 on the revolving rollers 15,16,17,18,19
are be placed so that the outer ends 23 of the spikes describe
circles that do overlap each other. As is clearly shown on the
figure two adjacent spikes will engage with each other like
toothed wheels.
The embodiment shown in fig. 3 has the advantage that the
revolving rollers 15,16,17,18,19 can be placed closer to each
other, whereby the fibres can be influenced by more than one
spike 12 at a time, providing a higher impact force on the
agglomerates, lumps and/or shadows, enabling a better
disintegration.
This is especially advantageously when the spikes 22 on the
revolving rollers are not flexible, as an impact between two
revolving and adjacent spikes can cause the spikes to break.
Fig. 5a and 5b shows a second embodiment 25 of the forming head
according to the invention. This embodiment basically

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23
corresponds to the first embodiment with a few modifications
and for like parts same reference numbers are used.
In fig 5a and 5b is assumed by way of example that the forming
head according to the invention comprises sixth distribution
units. This are of course in no manner intended to be limiting
for the invention, and the forming head can within the scope of
the present invention comprise from two to a plurality of
distributions units.
The forming head shown in fig. 5a and 5b comprises six
independent interconnected distribution units 26, 27, 28, 29,
30 and 31 respectively. Fibres are supplied to the first
distribution unit 26 via an inlet 6. A suction unit 7 is
positioned beneath a forming wire 8, and the forming head 25 is
positioned above the wire. Fibres are air laid on the forming
wire 8 to form a web in a dry forming process.
As shown in fig 5a and 5b the first, second and third
distribution units 25, 26 and 27 have a smaller horizontal
cross section than the underlying distribution units, i.e. the
forth, fifth and sixth distribution unit 28, 29 and 30.
The difference in the horizontal cross section ensures a
fluxuation in the air flow between the distribution units
having the smaller cross section and the distribution units
with the larger cross section, whereby an un-even air flow is
created that will ensure that the fibres are distributed and
spread more homogenously onto the underlying distribution
unit(s).
Inside each distribution unit revolving rollers are provided
with protruding spikes 12.
In the embodiment shown in fig. 5a and 5b the first
distribution unit 26 comprises one revolving roller 32, the

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second distribution unit 27 comprises two revolving rollers 33,
34, the third distribution unit 28 comprises one revolving
roller 35, the forth distribution unit 29 comprises one
revolving roller 36, the fifth distribution unit 30 comprises
two revolving rollers 37, 38, and the sixth distribution unit
28 comprises three revolving rollers 39, 40, 41 placed in a
substantially horizontal plane parallel to the forming wire 8.
The three revolving rollers 39, 40, 41, which are placed within
the sixth distribution unit, can be said to make up the bottom
of the forming head.
It will be evident for the person skilled in the art that the
number and dimensions of the revolving rollers and the
corresponding spikes can be arbitrarily adjusted depending on
the desired product and the fibres used.
Engines 20, arranged with the possibility for a variable
revolution rate, drives each revolving roller, ensuring that it
is possible to adjust the revolution rate of the engines
dependent of choice of rollers, spikes and the product, which
is to be formed.
A single engine 20 drives all revolving rollers in a
distribution unit. A synchronous transmission belt (not shown)
is used to transmit the force from said engine to the
respective revolving rollers. Thereby is obtained the
beneficial effect that the revolving rollers can be placed so
that the outer ends of the spikes describe circles that overlap
each other e.g. meshes like toothed gear. This embodiment has
the advantage that the revolving rollers can be placed closer
to each other, whereby the fibres can be influenced by more
than one spike at a time. This will provide a higher impact
force on the agglomerates, lumps and/or shadows, enabling a
better disintegration of the fibrous material. Furthermore,
when the outer ends of the spikes are transferred in-between

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each other, it becomes possible to manufacture a fibrous tissue
using very short fibres, for instance with lengths down to 3
mm. Hereby it becomes possible to achieve a very homogeneous
product with a very homogeneous profile in the sectional
5 direction as well as in the longitudinal direction.
It is of course possible to use individual engines for each
revolving roller in one distribution unit and a common engine
and a synchronous transmission belt for all revolving rollers
10 in a second distribution unit etc.
It should further be stressed that each distribution unit with
attached motor in the forming head is a "plug and go" and can
be pulled out and exchanged swiftly by hand, replaced by
15 another distribution unit, removed completely or an additional
distribution unit added to the forming head.

Representative Drawing