U.S. patent application number 11/678303 was filed with the patent office on 2007-11-29 for machine for producing a material web.
Invention is credited to Thomas Scherb, Luiz C. Silva, Hubert Walkenhaus.
Application Number | 20070272386 11/678303 |
Document ID | / |
Family ID | 35954051 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070272386 |
Kind Code |
A1 |
Scherb; Thomas ; et
al. |
November 29, 2007 |
MACHINE FOR PRODUCING A MATERIAL WEB
Abstract
The present invention provides a method and a press in a machine
for producing or processing a material web, in particular a fibrous
web, the press including a roller whose outer jacket is jointly
enwrapped, at least in one wrap zone, respectively by at least a
press belt, a support belt and a belt for dispersing water from the
material web. The water-dispersing belt is located on the inside in
contact with the outer jacket of the roller, the press belt on the
outside and the support belt between the press belt and the
water-dispersing belt. The material web is guided between the
support belt and the water-dispersing belt through the wrap zone.
At the end of the wrap zone, first the press belt is lifted off the
support belt and then the support belt with the material web is
lifted off the water dispersing belt.
Inventors: |
Scherb; Thomas; (Sao Paulo,
BR) ; Walkenhaus; Hubert; (Kerpen, DE) ;
Silva; Luiz C.; (Campo Limpo, BR) |
Correspondence
Address: |
Todd T. Taylor;Taylor & Aust, P.C.
142 S.Main Street
P.O. Box 560
Avilla
IN
46710
US
|
Family ID: |
35954051 |
Appl. No.: |
11/678303 |
Filed: |
February 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP05/55049 |
Oct 6, 2005 |
|
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|
11678303 |
Feb 23, 2007 |
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Current U.S.
Class: |
162/358.4 ;
162/202; 162/205; 162/358.3 |
Current CPC
Class: |
D21F 3/0272
20130101 |
Class at
Publication: |
162/358.4 ;
162/202; 162/358.3; 162/205 |
International
Class: |
D21F 11/00 20060101
D21F011/00; D21F 3/02 20060101 D21F003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 26, 2004 |
DE |
DE102004052157.3 |
Claims
1. A press in a machine for one of producing and processing a
material web, said press comprising: a press belt; a support belt;
a water-dispersing belt for dispersing water from the material web;
and a roller including an outer jacket, the press defining a wrap
zone, said outer jacket being jointly enwrapped, at least in one
said wrap zone, respectively by at least said press belt, said
support belt, and said water-dispersing belt, said water-dispersing
belt being located on an inside in contact with said outer jacket
of said roller, said press belt being located on an outside, said
support belt being between said press belt and said
water-dispersing belt, said support belt and said water-dispersing
belt configured for guiding the material web therebetween through
said wrap zone, at an end of said wrap zone said press belt being
configured for being lifted off said support belt and said support
belt being configured for being lifted off said water-dispersing
belt, with the material web, after said press belt is lifted off
said support belt.
2. The press according to claim 1, said roller includes at least
one suction zone including an end in a web running direction, said
end of said wrap zone being in a region of said end of said suction
zone in said web running direction.
3. The press according to claim 2, wherein said support belt is
configured for being lifted off said water-dispersing belt, with
the material web, in an arc angle range, relative to said end of
said suction zone, of between >0.degree. and <10.degree..
4. The press according to claim 2, wherein said support belt is
configured for being lifted off said water-dispersing belt, with
the material web, in an arc angle range, relative to said end of
said suction zone, of between >0.degree. and 6.degree..
5. The press according to claim 2, wherein said support belt is
configured for being lifted off said water-dispersing belt, with
the material web, in an arc angle range, relative to said end of
said suction zone, of between 2.degree. and 6.degree..
6. The press according to claim 2, wherein said water-dispersing
belt is configured for being lifted off said outer jacket of said
roller one of at said end of said suction zone and thereafter.
7. The press according to claim 1, wherein the material web is
configured for being exposed to an air through-flow, said press
belt, said support belt, the material web, and said
water-dispersing belt configured for passing said air through-flow
first through said press belt, then said support belt, then the
material web, and then through said water-dispersing belt.
8. The press according to claim 1, said press belt is configured
for being lifted off said support belt by between 0.degree. and
15.degree. before said support belt and the material web are lifted
off.
9. The press according to claim 1, said press belt is configured
for being lifted off said support belt by between 0.degree. and
10.degree. before said support belt and the material web are lifted
off.
10. The press according to claim 1, said press belt is configured
for being lifted off said support belt by between 2.degree. and
6.degree. before said support belt and the material web are lifted
off.
11. The press according to claim 1, wherein said support belt
includes one of a structured membrane and a structured mesh.
12. The press according to claim 11, wherein the material web
includes a fibrous web, said support belt configured for being a
structure on which the fibrous web is formed.
13. The press according to claim 11, wherein the material web
includes a fibrous web, the fibrous web having a gsm substance of
less than 42 g/cm.sup.2.
14. The press according to claim 13, wherein the material web
includes a fibrous web, the fibrous web being a tissue paper.
15. The press according to claim 1, wherein said support belt
includes a through air drying mesh.
16. The press according to claim 15, wherein the material web
includes a fibrous web, said through air drying mesh configured for
being a structure on which the fibrous web is formed.
17. The press according to claim 1, wherein said water-dispersing
belt is configured for at least one of being permeable for a fluid
and having a water absorption capacity.
18. The press according to claim 1, wherein the produced material
web is a fibrous web.
19. The press according to claim 18, wherein the fibrous web has a
specific bulk of over 10 g/cm.sup.3.
20. The press according to claim 18, wherein the fibrous web has a
specific bulk of over 14 g/cm.sup.3.
21. The press according to claim 18, wherein the fibrous web has a
specific bulk of over 16 g/cm.sup.3.
22. The press according to claim 18, wherein the fibrous web has a
water absorption capacity of more than 10 g water per gram fibrous
web.
23. The press according to claim 18, wherein the fibrous web has a
water absorption capacity of more than 14 g water per gram fibrous
web.
24. The press according to claim 18, wherein the fibrous web has a
water absorption capacity of more than 16 g water per gram fibrous
web.
25. A method for producing a material web, said method comprising
the steps of: forming a press nip by wrapping at least one press
belt around an outer jacket of a roller; passing the material web
through said press nip, the material web being positioned between a
support belt and a water-dispersing belt, said water-dispersing
belt being located on an inside in contact with said outer jacket
of said roller; and at an end of a wrap zone, first lifting said
press belt off said support belt and then lifting said support belt
with the material web off said water-dispersing belt.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of PCT application No.
PCT/EP2005/055049, entitled "MACHINE FOR PRODUCING A MATERIAL WEB",
filed Oct. 6, 2005.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a press in a machine for
producing or processing a material web, in particular a fibrous
web. Furthermore, this invention relates to a method for producing
a material web, in particular a fibrous web.
[0004] 2. Description of the Related Art
[0005] In particular for the production of tissue paper with a high
density and a high water absorption capacity, so-called bulky
tissue, it is necessary for the tissue web to be optimally
dewatered in each stage of production, meaning that in the press
section for example an optimum press pressure must be applied to
said tissue web at the correct moment for the necessary length of
time and the tissue web must be separated at the correct moment
from the paper machine covering or the respectively interacting
paper machine coverings.
[0006] What is needed in the art is a press and a method which are
respectively optimized in particular for the production of bulky
tissue products.
SUMMARY OF THE INVENTION
[0007] The present invention provides a press in a machine for
producing or processing a material web, in particular a fibrous
web, the press including a roller whose outer jacket is jointly
enwrapped, at least in one wrap zone, respectively by at least a
press belt, a support belt and a belt for dispersing water from the
material web, wherein the water-dispersing belt is located on the
inside in contact with the outer jacket of the roller, the press
belt on the outside and the support belt between the press belt and
the water-dispersing belt, and wherein the material web is guided
between the support belt and the water-dispersing belt through the
wrap zone. At the end of the wrap zone, first the press belt is
lifted off the support belt and then the support belt with the
material web is lifted off the water dispersing belt.
[0008] According to the present invention, first the press pressure
is removed from the material web, in particular the fibrous web,
which is being guided on the support belt. The actual dewatering,
which takes place essentially in the direction of the
water-dispersing belt, is thus ended. Then the support belt with
the material web is lifted off the water-dispersing belt in order
to prevent rewetting of the material web by the water-dispersing
belt.
[0009] Variations for constructing the water-dispersing belt are
possible. On the one hand the water-dispersing belt can be
permeable for water and gas such that water from the material web
can be dispersed through the water-dispersing belt by way of an air
flow or an air through-flow for example. In addition or
alternatively to this, the water-dispersing belt can have a water
absorption capacity. For example, it is possible to use a press
felt, a mesh or a mesh with a fine pore structure as the
water-dispersing belt.
[0010] According to another embodiment of the present invention,
the roller has a suction zone and the end of the wrap zone is in
the region of the end of the suction zone in the web running
direction. On the one hand the dewatering of the fibrous web in the
direction of the water-dispersing belt is increased as a result of
the suction zone, which is arranged on the side of the
water-dispersing belt facing away from the fibrous web. On the
other hand the rewetting of the fibrous web by the water-dispersing
belt is prevented as the result of the suction zone being arranged
at least in the region of the end of the wrap zone in that the
fibrous web is separated from the water-dispersing belt.
[0011] The fibrous web can be exposed to an air through-flow which
passes first through the press belt, then the support belt, then
the fibrous web and finally the water-dispersing belt.
[0012] According to another embodiment of the present invention,
the press belt is lifted off the support belt by between 0.degree.
and 15.degree., preferably 0.degree. and 10.degree., in particular
preferably 2.degree. and 6.degree., before the support belt and the
material web are lifted off. Advantage is drawn in this case from
the fact that two mutually conflicting effects have to be taken
into account: (1) on the one hand the dry content of the fibrous
web upon leaving the press should be as large as possible. This is
achieved by simultaneous pressing by the press belt and sucking by
the vacuum zone up to near the end of the vacuum zone; and (2) on
the other hand the press belt has to be lifted off the fibrous web
early enough to prevent rewetting of the fibrous web and belated
separation of the fibrous web from the press belt.
[0013] The present invention provides an optimum of the mutually
conflicting effects.
[0014] To prevent any rewetting of the material web, in particular
the fibrous web, by the belt dispersing the water from the material
web, it is necessary to lift off the fibrous web from the belt
dispersing the water from the material web ahead of, or at the
latest at, the end of the suction zone in order to ensure that the
fibrous web is in contact with the belt dispersing the water from
the material web only as long as dewatering from the fibrous web in
the direction of the belt dispersing the water from the material
web is guaranteed by the suction effect of the suction zone. Hence
the support belt with the material web should be lifted off ahead
of the end of the suction zone.
[0015] If, on the other hand, the lifting off of the support belt
takes place too early, this can lead to separation of the fibrous
web from the support belt and to tearing of the fibrous web.
[0016] Tests have shown that an optimum of the previously described
mutually conflicting effects is found when the support belt with
the material web is lifted off the belt dispersing the water from
the material web in an arc angle range, in relation to the end of
the suction zone, of between>0.degree. and <10.degree.,
preferably between >0.degree. and 6.degree., in particular
preferably between 2.degree. and 6.degree..
[0017] The belt dispersing the water from the material web can be
lifted off the outer jacket of the roller at the end of the suction
zone or thereafter. This ensures that the belt dispersing water
from the material web is in contact with the suction zone for as
long as possible, which, if the belt is a press felt and has a high
water absorption capacity for example, results in water being drawn
out of the belt over as long a section as possible.
[0018] In particular for the production of tissue papers it is
necessary to press the tissue web only on a zone basis in order to
obtain regions in the tissue web which were not compressed and
which therefore have a low density and hence a high water
absorption capacity. A structured mesh, in particular a TAD
(through air drying) mesh, or a structured membrane is ideal for
this purpose because it has a structure with elevations and
pockets. En route through the press the tissue web is only slightly
compressed in the region of the pockets as compared with the other
regions. An embodiment of the present invention provides
accordingly for the support belt to be a structured membrane or a
structured mesh, in particular a TAD mesh.
[0019] To increase runability it makes sense to transfer the
fibrous web in the still wet state as little as possible from one
covering to another covering. An embodiment of the invention thus
provides for the fibrous web to be formed on the support belt.
[0020] For the production of bulky tissue papers it makes sense for
the tissue web to be formed on a support belt with zonal pockets in
order to create regions with a high fiber mass. Another embodiment
of the invention thus provides for the fibrous web to be formed on
the TAD mesh.
[0021] The produced fibrous web can have a gsm substance (grams per
square meter substance weight or basis weight) of less than 42
g/cm.sup.2 and in particular is a tissue paper.
[0022] Furthermore, the fibrous web has a specific bulk of over 10
g/cm.sup.3, preferably over 14 g/cm.sup.3, in particular preferably
over 16 g/cm.sup.3.
[0023] In addition the fibrous web has a water absorption capacity
of more than 10 g water per g (gram) fibrous web, preferably more
than 14 g water per g fibrous web, in particular preferably more
than 16 g water per g fibrous web.
[0024] The invention relates also to a method for producing a
material web, in particular a fibrous web, with which the material
web is passed through a press nip, said press nip being formed by
wrapping at least one press belt around the outer jacket of a
roller, wherein the material web, positioned between a support belt
and a water-dispersing belt, is passed through the press nip, and
wherein the water-dispersing belt is located on the inside in
contact with the outer jacket of the roller, and wherein at the end
of the wrap zone first the press belt is lifted off the support
belt and then the support belt with the material web off the
water-dispersing belt.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of an embodiment of the invention
taken in conjunction with the accompanying drawings, wherein:
[0026] FIG. 1 shows a side view of a press according to the present
invention; and
[0027] FIG. 2 shows a detail of the press in FIG. 1.
[0028] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate one embodiment of the invention, and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Referring now to the drawings, and more particularly to FIG.
1, there is shown a press 1 on which a fibrous web 2 is dewatered
in a press nip 3.
[0030] The press 1 has a tensioned press belt 4, a support belt 5,
a water-dispersing belt 6 and a roller 7 with outer jacket 8. The
outer jacket 8 of the roller 7 is enwrapped by the press belt 4,
the support belt 5 and the water-dispersing belt 6 in a joint wrap
zone 9.
[0031] In the embodiment in question the press belt 4 is
constructed as a spiral mesh 4 from plastic or metal.
[0032] In the embodiment in question the support belt 5 is
constructed as a TAD mesh.
[0033] In the embodiment in question the water-dispersing belt 6 is
constructed as a press felt 6.
[0034] Outside the wrap region 9 the spiral mesh 4 is passed over a
multiplicity of rollers 18, 19, 20, 21 and 22, with the roller 18
serving as a tensioning roller.
[0035] Also outside the wrap zone 9 the press felt 6 is passed over
a multiplicity of rollers 23 to 28, the fibrous web 2 being brought
together with the press felt 6 in the region of the roller 28.
[0036] Likewise outside the wrap zone the press felt 6 is cleaned
by a cleaning device 29 and subsequently dried by a suction box 30
and a dryer 31.
[0037] The wrap zone has a beginning 10 and an end 11.
[0038] As is evident from FIG. 1, the press felt 6 makes contact,
on a side 12, with the outer jacket 8 of the roller 7. The spiral
mesh 4 is arranged on the outside and the TAD mesh 5 is arranged
between the spiral mesh 4 and the press felt 6.
[0039] The fibrous web 2 is guided between the TAD mesh 5 and the
press felt 6 through the wrap zone 9. By way of this arrangement a
press force is exerted by the spiral mesh 4 via the TAD mesh 5 onto
the fibrous web 2.
[0040] The wrap zone 9 accordingly forms the press nip 3.
[0041] In the region of the end 11 of the wrap zone 9, first the
spiral mesh 4 is lifted off the TAD mesh 5 and then the TAD mesh 5
with the fibrous web 2 is lifted off the press felt 6.
[0042] The roller 7 has a suction zone 13 with an end 14.
[0043] As is evident from FIG. 1, the end 11 of the wrap zone 9 is
arranged in the region of the suction zone 13 but ahead of the end
of the suction zone 13 in the web running direction 15.
[0044] Arranged above the roller 7 in the region of the suction
zone 13 is a blast box 16 which forces compressed air or steam 17
successively through the spiral mesh 4, the TAD mesh 5, the fibrous
web 2 and the press felt 6. Hence on the one hand the dewatering of
the fibrous web is promoted by the action of force in the direction
of the suction zone 13 and on the other hand the fibrous web 2 is
pre-dried by a through-flow of air.
[0045] FIG. 2 shows a detail in the region of the end 11 of the
wrap zone 9. As is evident from FIG. 2, the spiral mesh 4 is lifted
off the TAD mesh 5 at an arc angle .alpha..sub.B of 4.degree.
before the TAD mesh 5 and the fibrous web 2 are lifted off.
[0046] Furthermore, the TAD mesh 5 guiding the fibrous web 2 is
lifted off the press felt 6 at an arc angle .alpha..sub.W of
2.degree. in relation to the end 14 of the suction zone 13.
[0047] In addition, the press felt 6 is lifted off the outer jacket
8 of the roller 7 after the end 14 of the suction zone 13.
[0048] In the concrete embodiment the fibrous web 2 guided through
the press 1 is a web with a gsm substance (grams per square meter
substance weight or basis weight) of less than 42 g/cm.sup.2,
meaning in particular tissue paper with a high specific bulk in the
range of 16 g/cm.sup.3 and with a water absorption capacity of 16 g
water per g (gram) fibrous web.
[0049] While this invention has been described with respect to at
least one embodiment, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *