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EP 1 576 232 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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15.07.2009 Bulletin 2009/29 |
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Date of filing: 10.10.2003 |
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International Patent Classification (IPC):
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International application number: |
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PCT/FI2003/000751 |
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International publication number: |
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WO 2004/046459 (03.06.2004 Gazette 2004/23) |
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PRESS SECTION IN A PAPER OR BOARD MACHINE
PRESSENPARTIE EINER PAPIER- ODER PAPPENMASCHINE
SECTION DE PRESSE DANS UNE MACHINE A PAPIER OU A CARTON
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Designated Contracting States: |
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AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR |
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Priority: |
19.11.2002 FI 20022057
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Date of publication of application: |
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21.09.2005 Bulletin 2005/38 |
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Proprietor: Metso Paper, Inc. |
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00130 Helsinki (FI) |
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Inventors: |
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- HONKALAMPI, Petter
FIN-40930 Kinkomaa (FI)
- HALME, Petteri
FIN-40250 Jyväskylä (FI)
- ANTTILAINEN, Sami
FIN-40250 Jyväskylä (FI)
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Representative: TBK-Patent |
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Bavariaring 4-6 80336 München 80336 München (DE) |
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References cited: :
EP-A1- 0 487 483 FI-B- 109 481 US-B1- 6 210 530
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WO-A1-97/13030 US-B1- 6 197 156
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention relates to a press section for a paper or board machine according to
the preamble of claim 1. A press section comprising the features summarized in the
preamble of claim 1 is known from document
US-B1-6 210 530.
[0002] The invention relates to a press section for a paper or board machine which is provided
with at least a forming section, a press section and a dryer section and in which
the press section is provided with separate press nips. In this patent, by a separate
press nip is meant a press nip in which opposing press members define only one press
nip. A separate press nip can be a roll nip or an extended nip. The opposite of a
press section provided with separate press nip is a press section which is provided
with a centre roll and in which the centre roll forms press nips with at least two
other rolls.
[0003] Document
WO 00/55 423 A1 discloses a method and an arrangement for treating a paper or board web. Figs. 4-6
show control of the surface properties of a web with chemicals, and examples suitable
for a smoothing press nip. In these exemplifying embodiments, a tandem transfer belt
is used underneath in the second and third nips. Dewatering is not symmetric because
dewatering takes place in both directions in the first nip, upwards in the second
nip, and no dewatering takes place in the third nip, but, instead, there is smoothing
and application of the web because belts are placed on both sides of the web. Thus,
the third press nip of these embodiments does not increase dry solids even though
it improves the surface properties of the web, thus increasing the overall length
of the paper machine.
[0004] Document
FI 95 610 C discloses a press section of a paper machine provided with a smoothing press. The
paper web has a closed and supported draw through the press section and the press
section comprises at least two successive separate press nips, dewatering of the paper
web being carried out at least in the first one of said press nips, preferably between
two press fabrics that receive water. The last press nip in the press section is a
smoothing press nip which is separate from the preceding nip and in which no substantial
dewatering is performed. The paper web is passed through the smoothing press nip from
the preceding dewatering press nip on a transfer belt substantially not receiving
water, on its substantially straight run, which is continued after the smoothing nip
as a run of substantially the same direction, on which run some of the elongation
of the paper web in the machine direction can be compensated for, which elongation
takes place in the smoothing nip, by a difference in speed of the transfer belt.
[0005] Document
US 6 210 530 B1 discloses a press section and a method for pressing with shoe presses of different
lengths. Fig. 2 shows an embodiment comprising three shoe press units in which the
web is first passed through the first and the second shoe press unit which are placed
underneath a counter roll, i.e. underneath the web, and the third shoe press is placed
above a counter roll, i.e. above the web.
[0006] Document
WO 99/60 202 A1 discloses a press section of a paper machine applying one or more press nips, through
which the paper web to be pressed is passed as a substantially closed draw and in
which press section there is at least one press nip provided with two water-receiving
press felt, through which press nip the paper web runs between the press felts and
after which last-mentioned nip the paper web is separated from one of the press felts
and transferred on support of the other press felt substantially as a closed draw
further. The last nip in the press section is an extended nip zone, in which one roll
is a shoe roll provided with a hose shell and with a press shoe arrangement and the
other roll is a press suction roll provided with a suction zone. The paper web is
passed through the last extended nip zone between two water-receiving press fabrics
and directly after the last extended nip zone the paper web is separated from one
of the press fabrics and transferred, with the aid of a vacuum present in a suction
zone of said press suction roll, to follow the press fabric placed at the side of
said press suction roll without substantial rewetting, and the paper web is passed
on the latter press fabric as a closed draw onto a drying wire or equivalent of a
dryer section following after the press section, onto which drying wire or equivalent
the web is transferred as a suction roll transfer or by means of an equivalent arrangement.
[0007] Document
US 5 888 354 A discloses press section geometries in which a press section provided with a closed
draw of a web in a paper or board machine comprises a first water-receiving upper
fabric onto which the web is transferred on a suction zone of a pick-up roll from
a forming wire at a pick-up point situated after its suction roll and after that there
is a wire drive roll, from which the return run of the wire begins. The press comprises
one or two successive press nips which press water from the web and between which
the web has a totally closed draw such that it is supported by a fabric all the time.
The press nips removing water are so-called extended nips, whose press zone is substantially
longer than that of a sharp roll nip, and all press nips are additionally provided
with two water-receiving press fabrics so that water is removed in them substantially
symmetrically through both surfaces of the web. In addition, the embodiments shown
in Figs. 1, 2 and 3 make use of a lightly loaded transfer nip, which nip is defined
by a press roll, provided with a recessed surface and disposed within an upper wire
loop, together with a first drying cylinder or equivalent.
[0008] Document
FI 109 481 B discloses a press section which is provided with only two separate press nips. A
transfer belt is passed through the second nip together with a water-receiving fabric,
and a transfer roll for transferring the web onto the water-receiving fabric of the
second nip is formed as a transfer suction roll having a suction zone.
[0009] Document
EP-A1-0 487 483 discloses in Fig. 5 a press section provided with three separate press nips. Two
water-receiving fabrics are passed through each of these nips. A first transfer roll
and a second transfer roll are formed as transfer suction rolls having a suction zone.
[0010] Document
WO 9 713 030 A1 discloses in Fig. 4 a press section having three separate nips, wherein the second
nip has an upper water-receiving fabric and a transfer belt not receiving water and
wherein the third nip has an upper water-receiving fabric and a transfer belt not
receiving water.
[0011] One problem in the press sections known in the state of the art is absorption asymmetry,
which is caused because the composition/structure of the web in the thickness direction
changes in every pressing operation in which water is not removed in an equal amount
in both directions because some of the fines and filler material of the web is washed
with water. Fines accumulate in the surface parts of the web where dewatering has
been stronger. The problem can also be affected in a wire section but the press is
the last dewatering member by which the problem can actually be affected. Even in
good paper, the middle layer becomes poor in fines but on both sides of the web there
is an equal amount of fines moving and adhering close to the surfaces.
[0012] In surface topography, missing dots in the print and the absorption of the top and
bottom surfaces of paper and its asymmetry are a significant drawback in modem press
sections having a closed draw when these are applied to printing paper. When the speed
increases so that it is over 2000 m/min, closed draw provides a considerable runnability
benefit in speed potential and efficiency. One object of the invention is to develop
further a press section that has a closed draw and is suitable for speeds over 1800
m/min and advantageously over 2000 m/min, at which there are no problems with surface
topography and absorption symmetry described above.
[0013] It is an object of the present invention is to provide a press section for a paper
or board machine which makes it possible to optimize surface topography and absorption
at a speed over 1800 m/min and advantageously over 2000 m/min.
[0014] According to the invention, this object is achieved by the press section defined
in claim 1. Advantageous further developments of the press section are defined in
the dependent claims.
[0015] In the press section in accordance with the invention, closed draw through the press
section is accomplished as a substantially straight run and the press section includes
at least three separate press nips which do not have any fabric loops in common with
one another.
[0016] In the press section in accordance with the invention, the first press nip in the
running direction of the web can be a roll nip or a press suction roll nip, advantageously
at lower speeds of over 1800 m/min, but with speeds increasing over 2000 m/min and
with increasing dewatering need, an extended nip becomes an advantageous alternative.
It is conceivable that in the case of three nips at high speeds all the nips are extended
nips and, on the other hand, in the case of more nips than three at a lower speed
mere roll nips can be used. The next two nips each have only one water-receiving fabric,
which is placed in each nip on the opposite side of paper with respect to the other
nip in the machine direction. In said successive nips, both sides of the web are smoothed/evened
out one at a time mechanically against a smooth surface, which smooth surface is the
surface of a smooth transfer belt. In that connection, removal of water from the web
takes place in the nip only in a direction away from the smooth surface, i.e. to the
side of the water-receiving fabric. By this means, in the successive nips an equal
amount of fines affecting absorption is provided in the vicinity of both surfaces.
[0017] Transfer from the press section in accordance with the invention to a dryer section
takes place, as known in itself, from a transfer belt, and in the embodiments in which
a smooth surface is in an upper position in the last nip of the press section, transfer
from a lower felt is used.
[0018] In the smoothing/evening out nips provided with a smooth transfer belt in the press
section in accordance with the invention, there is a water-receiving press fabric
and a press roll on the other side. With lower load needs it is possible to use an
ordinary press suction roll, and at higher loads it is advantageous to use a press
suction roll that is manufactured by means of powder metallurgy, in which case the
wall thickness of the suction roll need not be increased. For example, by means of
the suctions of the last smoothing nips it is ensured that the web follows the felt,
and a high load is not necessarily needed. Similarly, in the roll/extended nips at
the beginning, increased dewatering is achieved by means of a higher load using a
suction roll of powder metallurgy. A press suction roll manufactured by means of powder
metallurgy is described, for example, in document
FI 100 422 B. The suction roll assures that the web remains on the surface of a porous fabric
so that it shall not start following the more adhesive smooth surface of a transfer
belt. The smooth surfaces of press nips also affect the surfaces of the web mechanically,
evening out the decrease of smoothness caused by coarse press fabrics. Shoe presses
can also be used in connection with the invention.
[0019] The press section in accordance with the invention provides good surface properties
of the web in respect of printability and also makes it possible to use high speeds,
over 1800 m/min and advantageously over 2000 m/min, and enables good efficiency with
a good moisture profile.
[0020] The press section in accordance with the invention also facilitates the adjustment
of two-sidedness that takes place further in the paper machine line and which can
be performed mainly by means of calendering and application of chemicals. The bulk
possibly lost during pressing can be saved later by means of lighter calendering,
which can be optimized further according to other desired surface properties, as there
is no need to correct absorption a symmetry. On the other hand, when press dry solids
increase in more press nips than conventional, it may be possible to manage with a
shorter dryer section even though the press section becomes longer.
[0021] In one advantageous embodiment of the invention there are three press nips, a closed
draw of the web through the press section and, in the first nip, dewatering takes
place on two sides, thus providing a symmetric web. After the first nip, the web is
transferred from the surface of an upper felt to a second nip and, in the second nip,
dewatering takes place downwards and the upper surface of the web is against a smooth
transfer belt. In the third nip, dewatering takes place upwards and the lower surface
of the web is against a transfer belt and the transfer of the web is from a lower
fabric to a dryer section. In accordance with one advantageous additional feature,
a roll press is placed after the first nip in the second nip, whereby a sufficient
material displacement is achieved in the second nip, i.e. displacement of fines to
the side of the lower surface of the web. At the same time, the smoothness of the
upper surface of the web improves because it is pressed against a smooth surface.
[0022] In the following, some embodiments of the invention are described with reference
to the figures of the appended drawing, but the invention is not meant to be exclusively
limited to the details of the figures.
Figure 1A is a schematic view of one embodiment of the invention.
Figure 1B is a schematic view of one alternative application of the embodiment of
the invention shown in Fig. 1A.
Figure 1C is a schematic view of one variant of the first press nip in the embodiment
of the invention shown in Fig. 1A.
[0023] In the following figures, the same reference numerals are used of parts that correspond
to one another.
[0024] In Fig. 1A, a web W formed in a forming section is passed to a pick-up point P situated
on a forming wire 10 before reversing rolls 11, 12 placed within the loop of the forming
wire 10. The pick-up point P is formed between the forming wire 10 and a roll 24 placed
within the loop of a first water-receiving press felt 20 and provided with a suction
sector 24a, so that the web W runs at the pick-up point P between the forming wire
10 and the first press felt 20. At the pick-up point P, the web W is separated from
the forming wire 10 and transferred to be supported by the first press felt 20. After
that, the web W is transferred on support of the lower surface of the first press
felt 20 to a first press nip N1, which is defined by two recessed surface press roll
22 and 23 to form therebetween a roll nip N1 or a press suction roll nip (Fig. 1C),
in which case the upper roll 22 is a press suction roll provided with a suction zone
and the other roll 23 is a recessed surface roll. In that connection, a felt suction
roll 25 can be omitted. The web W runs in the first press nip N1 between the first
water-receiving press felt 20 serving as an upper press fabric and a second water-receiving
press felt 21 serving as a lower press fabric. Dewatering of the web W takes place
in the first press nip N1 into both press felts 20,21. In the embodiments which use
a press suction roll, water is also removed through a suction zone into the suction
roll.
[0025] After the first press nip N1, the travel of the web W with the upper press felt 20
is assured by means of a vacuum in a suction zone 25a of an upper suction roll 25,
and the web W is separated from the first press felt 20 by means of a vacuum in a
suction zone 34a of a lower transfer suction roll 34 and caused to adhere to a lower
fabric 30, on the upper surface of which the web W is transferred to a second press
nip N2, which is defined between a roll 32 and a press roll 33. The second press nip
N2 is formed such that in the second nip 42 there is an upper transfer belt 31 and
as the lower fabric 30, there is a press felt 30. From the second nip N2 the web W
is passed on the lower surface of the transfer belt 31 onto a transfer fabric 60,
onto which the web W is transferred by means of suction zone 64a of a transfer suction
roll 64, and on support of the transfer fabric 60 the web W is passed by means of
a suction zone 44a of a suction roll 44 to be transferred so as to be supported by
a subsequent upper fabric 40 and to a third press nip N3, which is defined between
an extended nip press roll 42 and a counter roll 43. Underneath there is a transfer
belt 41, by means of which the web W is passed to a transfer suction roll 54 having
a suction zone 54a, by means of which the web is transferred onto a drying wire 50
of a dryer section. Dewatering of the web W takes place in the third press nip N3
into the upper press felt 40.
[0026] The embodiment of the invention shown in Fig. 1B mainly corresponds to the embodiment
shown in Fig. 1A except that each nip N1, N2, N3 has been formed into an extended
nip, in which one roll is an extended nip roll 22; 33; 42 and the other roll is its
counter roll 23; 32; 43.
1. A press section for a paper or board machine, in which press section the transfer
of a web (W) is accomplished as a closed draw through the press section, the closed
draw of the web (W) through the press section being accomplished as a substantially
straight run, and which press section is provided with at least three separate press
nips (N1, N2, N3),
wherein the first press nip (N1) of said press nips (N1, N2, N3) has two water-receiving
fabrics (20, 21) and dewatering in said first nip (N1) takes place on two sides,
wherein each of the nips (N2, N3) following after said first nip (N1) in the running
direction of the web (W) have only one water-receiving fabric (30, 40), which is placed
in the nip (N2, N3) on the opposite side of the web (W) with respect to the adjacent
nip (N3, N2) or nips of said nips (N2, N3) following after said first nip (N1),
wherein said press nips (N1, N2, N3) each have their own water-receiving fabric (30,
41) or water-receiving fabrics (20, 21),
wherein in the loop of the water-receiving fabric (30) of the second nip (N2) a first
transfer roll (34) is provided at a transfer position for transferring the web (W)
from one of the water-receiving fabrics (20, 21) of said first nip (N1) to the water-receiving
fabric (30) of said second nip (N2), and
wherein in the loop of the water-receiving fabric (40) of the third nip (N3), which
is the nip following after said second nip (N2) in the running direction of the web
(W), a second transfer roll (44) is provided at a transfer position for transferring
the web (W) to the water-receiving fabric (40) of said third nip (N3),
characterized
in that said first transfer roll is a transfer suction roll (34) having a suction zone (34a),
in that together with the water-receiving fabric (30) of said second nip (N2), a smooth transfer
belt (31) is passed through said second nip (N2), wherein the transfer belt (31) is
passed only through said second nip (N2),
in that a transfer fabric (40) is located downstream of said second nip (N2), wherein in
the loop of the transfer fabric (40), a third transfer suction roll (64) having a
suction zone (64a) is provided at a transfer position for transferring the web (W)
from said transfer belt (31) of said second nip (N2) to said transfer fabric (40),
in that said second transfer roll is a transfer suction roll (44) having a suction zone (44a)
and is arranged to transfer the web (W) to the water-receiving fabric (40) of said
third nip (N3) from said transfer fabric (60), and
in that together with the water-receiving fabric (30) of said third nip (N3), a smooth transfer
belt (41) is passed through said third nip (N3), wherein the transfer belt (41) is
passed only through said third nip (N3).
2. The press section as claimed in claim 1, characterized in that in said second nip (N2) dewatering is downwards, and in that the web (W) is arranged to be transferred from the surface of an upper one of the
two water-receiving fabrics (20, 21) of said first nip (N1) onto the water-receiving
fabric (30) of said second nip (N2).
3. The press section as claimed in claim 1 or 2, characterized in that at least one of said first and second nips (N1, N2) is an extended nip.
4. The press section as claimed in claim 3, characterized in that said first nip (N1) is an extended nip.
5. The press section as claimed in claim 1 or 2, characterized in that at least one of the nips following after said first nip (N1) is an extended nip.
6. The press section as claimed in claim 5, characterized in that all of said nips (N1, N2, N3) are extended nips.
7. The press section as claimed in one of claims 3 to 6, characterized in that the extended nip or nips comprise a press suction roll.
8. The press section as claimed in one of claims 1 to 3 and 5, characterized in that said first nip (N1) is a roll nip.
9. The press section as claimed in claim 8, characterized in that all of said nips (N1, N2, N3) of the press section are roll nips.
10. The press section as claimed in claim 8 or 9, characterized in that the roll nip or roll nips comprise a press suction roll.
11. The press section as claimed in claim 7 or 10, characterized in that the press suction roll or rolls is/are manufactured by means of powder metallurgy.
12. The press section as claimed in one of claims 1 to 11, characterized in that the press section is arranged to be used at running speeds over 1800 m/min.
13. The press section as claimed in claim 12, characterized in that the press section is arranged to be used at running speeds over 2000 m/min.
1. Pressenpartie für eine Papier- oder Kartonmaschine, wobei in der Pressenpartie die
Übertragung einer Bahn (W) als ein geschlossener Zug durch die Pressenpartie ausgeführt
wird, wobei der geschlossene Zug der Bahn (W) durch die Pressenpartie als ein im Wesentlichen
gerader Lauf ausgeführt wird, und wobei die Pressenpartie mit wenigstens drei separaten
Pressspalten (N1, N2, N3) versehen ist,
wobei der erste Pressspalt (N1) der Pressspalten (N1, N2, N3) zwei wasseraufnehmende
Gewebe (20, 21) hat und ein Entwässern in dem ersten Spalt (N1) auf zwei Seiten stattfindet,
wobei jeder von den Spalten (N2, N3), die nach dem ersten Spalt (N1) in der Laufrichtung
der Bahn (W) folgen, nur ein wasseraufnehmendes Gewebe (30, 40) haben, das in dem
Spalt (N2, N3) auf der entgegengesetzten Seite der Bahn (W) mit Hinblick auf den benachbarten
Spalt (N3, N2) oder Spalten der Spalten (N2, N3), die nach dem ersten Spalt (N1) folgen,
platziert ist,
wobei die Pressspalten (N1, N2, N3) jeweils ihr eigenes wasseraufnehmendes Gewebe
(30, 41) oder wasseraufnehmende Gewebe (20, 21) haben,
wobei in dem Umlauf des wasseraufnehmenden Gewebes (30) des zweiten Spalts (N2) eine
erste Übertragungswalze (34) an einer Übertragungsposition zum Übertragen der Bahn
(W) von einem der wasseraufnehmenden Gewebe (20, 21) des ersten Spalts (N1) an das
wasseraufnehmende Gewebe (30) des zweiten Spalts (N2) vorgesehen ist, und
wobei in dem Umlauf des wasseraufnehmenden Gewebes (40) des dritten Spalts (N3), welcher
der Spalt ist, der nach dem zweiten Spalt (N2) in der Laufrichtung der Bahn (W) folgt,
eine zweite Übertragungswalze (44) an einer Übertragungsposition zum Übertragen der
Bahn (W) an das wasseraufnehmende Gewebe (40) des dritten Spalts (N3) vorgesehen ist,
dadurch gekennzeichnet,
dass die erste Übertragungswalze eine Übertragungssaugwalze (34) mit einer Saugzone (34a)
ist,
dass zusammen mit dem wasseraufnehmenden Gewebe (30) des zweiten Spalts (N2) ein glattes
Übertragungsband (31) durch den zweiten Spalt (N2) hindurchgeführt wird, wobei das
Übertragungsband (31) nur durch den zweiten Spalt (N2) hindurchgeführt wird,
dass sich ein Übertragungsgewebe (14) stromabwärtig des zweiten Spalts (N2) befindet,
wobei in dem Umlauf des Übertragungsgewebes (40) eine dritte Übertragungssaugwalze
(64) mit einer Saugzone (64a) an einer Übertragungsposition zum Übertragen der Bahn
(W) von dem Übertragungsband (31) des zweiten Spalts (N2) an das Übertragungsgewebe
(40) vorgesehen ist,
dass die zweite Übertragungswalze eine Übertragungssaugwalze (44) mit einer Saugzone (44a)
ist und angeordnet ist, um die Bahn (W) von dem Übertragungsgewebe (40) an das wasseraufnehmende
Gewebe (40) des dritten Spalts (N3) zu übertragen, und
dass zusammen mit dem wasseraufnehmenden Gewebe (30) des dritten Spalts (N3) ein glattes
Übertragungsband (41) durch den dritten Spalt (N3) hindurchgeführt wird, wobei das
Übertragungsband (41) nur durch den dritten Spalt (N3) hindurchgeführt wird.
2. Pressenpartie nach Anspruch 1, dadurch gekennzeichnet, dass in dem zweiten Spalt (N2) ein Entwässern nach unten stattfindet, und dadurch, dass die Bahn (W) angeordnet ist, um von der Fläche eines oberen Gewebes von den
zwei wasseraufnehmenden Geweben (20, 21) des ersten Spalts (N1) auf das wasseraufnehmende
Gewebe (30) des zweiten Spalts (N2) übertragen zu werden.
3. Pressenpartie nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass wenigstens einer von dem ersten und dem zweiten Spalt (N1, N2) ein Langspalt ist.
4. Pressenpartie nach Anspruch 3, dadurch gekennzeichnet, dass der erste Spalt (N1) ein Langspalt ist.
5. Pressenpartie nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass wenigstens ein Spalt von den Spalten, die nach dem ersten Spalt (N1) folgen, ein
Langspalt ist.
6. Pressenpartie nach Anspruch 5, dadurch gekennzeichnet, dass alle von den Spalten (N1, N2, N3) Langspalte sind.
7. Pressenpartie nach einem der Ansprüche 3 bis 6, dadurch gekennzeichnet, dass der Langspalt oder Spalten eine Presssaugwalze aufweisen.
8. Pressenpartie nach einem der Ansprüche 1 bis 3 und 5, dadurch gekennzeichnet, dass der erste Spalt (N1) ein Walzenspalt ist.
9. Pressenpartie nach Anspruch 8, dadurch gekennzeichnet, dass alle von den Spalten (N1, N2, N3) der Pressenpartie Walzenspalte sind.
10. Pressenpartie nach Anspruch 8 oder 9, dadurch gekennzeichnet, dass der Walzenspalt oder die Walzenspalte eine Presssaugwalze aufweisen.
11. Pressenpartie nach Anspruch 7 oder 10, dadurch gekennzeichnet, dass die Presssaugwalze oder -walzen mittels Pulvermetallurgie hergestellt ist/sind.
12. Pressenpartie nach einem der Ansprüche 1 bis 11, dadurch gekennzeichnet, dass die Pressenpartie angeordnet ist, um bei Laufgeschwindigkeiten über 1800 m/min verwendet
zu werden.
13. Pressenpartie nach Anspruch 12, dadurch gekennzeichnet, dass die Pressenpartie angeordnet ist, um bei Laufgeschwindigkeiten über 2000 m/min verwendet
zu werden.
1. Section des presses pour une machine à papier ou à carton, section des presses dans
laquelle le transfert d'une bobine (W) est réalisé comme un tirage fermé à travers
la section des presses, le tirage fermé de la bobine (W) à travers la section des
presses étant réalisé comme un avancement essentiellement direct, et laquelle section
des presses est pourvue d'au moins trois lignes de contact (N1, N2, N3) de presses
séparées,
dans laquelle la première ligne de contact (N1) de presses parmi lesdites lignes de
contact (N1, N2, N3) de presses possède deux toiles (20, 21) de réception d'eau et
l'essorage dans ladite première ligne de contact (N1) se fait sur deux faces,
dans laquelle chacune des lignes de contact (N2, N3) qui suivent ladite première ligne
de contact (N1) dans la direction d'avancement de la bobine (W) possède une seule
toile (30, 40) de réception d'eau, qui est placée dans la ligne de contact (N2, N3)
sur la face opposée de la bobine (W) par rapport à la ligne de contact adjacente (N3,
N2) ou aux lignes de contact desdites lignes de contact (N2, N3) qui suivent ladite
première ligne de contact (N1),
dans laquelle lesdites lignes de contact (N1, N2, N3) de presses ont chacune leur
toile (30, 41) de réception d'eau ou toiles (20, 21) de réception d'eau,
dans laquelle dans la boucle de la toile (30) de réception d'eau de la deuxième ligne
de contact (N2), un premier rouleau de transfert (34) est pourvu à une position de
transfert pour transférer la bobine (W) de l'une des toiles (20, 21) de réception
d'eau de ladite première ligne de contact (N1) vers la toile (30) de réception d'eau
de ladite deuxième ligne de contact (N2), et
dans laquelle dans la boucle de la toile (40) de réception d'eau de la troisième ligne
de contact (N3), qui est la ligne de contact qui suit ladite deuxième ligne de contact
(N2) dans la direction d'avancement de la bobine (W), un deuxième rouleau de transfert
(44) est pourvu à une position de transfert pour transférer la bobine (W) vers la
toile (40) de réception d'eau de ladite troisième ligne de contact (N3),
caractérisée
en ce que ledit premier rouleau de transfert est un rouleau de transfert (34) par aspiration
ayant une zone d'aspiration (34a),
en ce que avec la toile (30) de réception d'eau de ladite deuxième ligne de contact (N2), on
fait passer une courroie de transfert lisse (31) à travers ladite deuxième ligne de
contact (N2), où la courroie de transfert (31) passe uniquement à travers ladite deuxième
ligne de contact (N2),
en ce qu'une toile de transfert (40) est située en aval de ladite deuxième ligne de contact
(N2), dans laquelle dans la boucle de la toile de transfert (40), un troisième rouleau
de transfert (64) par aspiration ayant une zone d'aspiration (64a) est pourvu à une
position de transfert pour transférer la bobine (W) de ladite courroie de transfert
(31) de ladite deuxième ligne de contact (N2) vers ladite toile de transfert (40),
en ce que ledit deuxième rouleau de transfert est un rouleau de transfert (44) par aspiration
ayant une zone d'aspiration (44a) et est agencé pour transférer la bobine (W) vers
la toile (40) de réception d'eau de ladite troisième ligne de contact (N3) depuis
ladite toile de transfert (60), et
en ce que avec la toile (30) de réception d'eau de ladite troisième ligne de contact (N3),
on fait passer une courroie de transfert lisse (41) à travers ladite troisième ligne
de contact (N3), dans laquelle la courroie de transfert (41) passe uniquement à travers
ladite troisième ligne de contact (N3).
2. Section des presses telle que revendiquée dans la revendication 1, caractérisée en ce que, dans ladite deuxième ligne de contact (N2), l'essorage se fait vers le bas, et en ce que la bobine (W) est agencée de façon à être transférée de la surface d'une toile supérieure
parmi les deux toiles (20, 21) de réception d'eau de ladite première ligne de contact
(N1) sur la toile (30) de réception d'eau de ladite deuxième ligne de contact (N2).
3. Section des presses telle que revendiquée dans la revendication 1 ou 2, caractérisée en ce qu'au moins l'une desdites première et deuxième lignes de contact (N1, N2) est une ligne
de contact étendue.
4. Section des presses telle que revendiquée dans la revendication 3, caractérisée en ce que ladite première ligne de contact (N1) est une ligne de contact étendue.
5. Section des presses telle que revendiquée dans la revendication 1 ou 2, caractérisée en ce qu'au moins l'une des lignes de contact qui suit ladite première ligne de contact (N1)
est une ligne de contact étendue.
6. Section des presses telle que revendiquée dans la revendication 5, caractérisée en ce que l'ensemble desdites lignes de contact (N1, N2, N3) sont des lignes de contact étendues.
7. Section des presses telle que revendiquée dans l'une des revendications 3 à 6, caractérisée en ce que la ligne de contact ou les lignes de contact étendue(s) comprennent un rouleau de
presse à aspiration.
8. Section des presses telle que revendiquée dans l'une des revendications 1 à 3 et 5,
caractérisée en ce que ladite première ligne de contact (N1) est une ligne de contact de rouleau.
9. Section des presses telle que revendiquée dans la revendication 8, caractérisée en ce que l'ensemble desdites lignes de contact (N1, N2, N3) de la section des presses sont
des lignes de contact de rouleaux.
10. Section des presses telle que revendiquée dans la revendication 8 ou 9, caractérisée en ce que la ligne de contact de rouleau ou les lignes de contact de rouleaux comprennent un
rouleau de presse à aspiration.
11. Section des presses telle que revendiquée dans la revendication 7 ou 10, caractérisée en ce que le rouleau ou les rouleaux de presse à aspiration est/sont fabriqué(s) grâce à la
métallurgie des poudres.
12. Section des presses telle que revendiquée dans l'une des revendications 1 à 11, caractérisée en ce que la section des presses est agencée de façon à être utilisée à des vitesses d'avancement
au-dessus de 1800 m/min.
13. Section des presses telle que revendiquée dans la revendication 12, caractérisée en ce que la section des presses est agencée de façon à être utilisée à des vitesses d'avancement
au-dessus de 2000 m/min.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description