U.S. patent application number 13/768422 was filed with the patent office on 2014-02-27 for apparatus for producing a material web.
This patent application is currently assigned to VOITH PATENT GMBH. The applicant listed for this patent is VOITH PATENT GMBH. Invention is credited to Andreas Meschenmoser.
Application Number | 20140053998 13/768422 |
Document ID | / |
Family ID | 44512829 |
Filed Date | 2014-02-27 |
United States Patent
Application |
20140053998 |
Kind Code |
A1 |
Meschenmoser; Andreas |
February 27, 2014 |
APPARATUS FOR PRODUCING A MATERIAL WEB
Abstract
An apparatus for producing a fibrous web, in particular a
tissue, paper or cardboard web, has a forming section and a dryer
section, whereby the dryer section includes a pressure nip formed
by a suction roll and a press roll, a drying cylinder and a
transfer pressure nip which is positioned downstream from the
pressure nip for transferring the fibrous web to the drying
cylinder, whereby the fibrous web together with a clothing wraps
around the suction roll in a wraparound region in such a way that
the clothing is positioned between the suction roll and the fibrous
web.
Inventors: |
Meschenmoser; Andreas;
(Horgenzell, DE) |
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Applicant: |
Name |
City |
State |
Country |
Type |
VOITH PATENT GMBH; |
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|
US |
|
|
Assignee: |
VOITH PATENT GMBH
Heidenheim
DE
|
Family ID: |
44512829 |
Appl. No.: |
13/768422 |
Filed: |
February 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2011/062196 |
Jul 18, 2011 |
|
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13768422 |
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Current U.S.
Class: |
162/290 |
Current CPC
Class: |
D21F 3/0272 20130101;
D21F 9/003 20130101; D21F 11/006 20130101; D21F 9/04 20130101; D21F
11/14 20130101 |
Class at
Publication: |
162/290 |
International
Class: |
D21F 9/04 20060101
D21F009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 18, 2010 |
DE |
10 2010 039 456.4 |
Claims
1. An apparatus for producing a web of fibrous material, said
apparatus comprising: a forming section; a clothing; a dryer
section including a suction roll, a press roll, a drying cylinder,
a transfer pressure nip, and a heating device, said suction roll
and said press roll forming a pressure nip, said transfer pressure
nip being positioned downstream from said pressure nip and being
configured for transferring the web to said drying cylinder, the
web together with said clothing wrapping around said suction roll
in a wraparound region in such a way that said clothing is
positioned between said suction roll and the web, said wraparound
region being located upstream of said pressure nip, said heating
device being assigned directly to the web in said wraparound
region.
2. The apparatus according to claim 1, wherein the web is one of a
tissue web, a paper web, and a cardboard web.
3. The apparatus according to claim 1, wherein said clothing is a
textured fabric.
4. The apparatus according to claim 1, further including an inside
felt, said suction roll being partially wrapped by said inside felt
which is positioned between said clothing and said suction
roll.
5. The apparatus according to claim 4, wherein said inside felt is
routed through said transfer pressure nip.
6. The apparatus according to claim 4, wherein said inside felt is
more compressible than said clothing.
7. The apparatus according to claim 1, wherein said clothing is a
water-absorbing felt.
8. The apparatus according to claim 1, wherein said heating device
is one of a steam blow box and a hot air blower hood.
9. The apparatus according to claim 1, wherein the apparatus
includes a region of said wraparound region and a region of said
pressure nip, said suction roll including a suction box at least
one of (a) in said region of said wraparound region, (b) in said
region of said pressure nip, and (c) after said pressure nip,
providing at least one suction zone.
10. The apparatus according to claim 1, wherein the apparatus
includes a region of said wraparound region and a region of said
pressure nip, said suction roll including a suction box at least
one of (a) in said region of said wraparound region, (b) in said
region of said pressure nip, and (c) after said pressure nip,
providing a plurality of suction zones.
11. The apparatus according to claim 1, wherein a distance between
said forming section and said dryer section is greater than a
transfer distance created by a distance between said pressure nip
and said transfer pressure nip.
12. The apparatus according to claim 11, wherein said transfer
distance is shorter than 3 meters.
13. The apparatus according to claim 11, wherein said transfer
distance is shorter than 2 meters.
14. The apparatus according to claim 11, wherein said transfer
distance is shorter than 1.5 meters.
15. The apparatus according to claim 1, further including an
outside felt, said outside felt being partially wrapped around said
press roll.
16. The apparatus according to claim 1, wherein said clothing and
the web are routed through said transfer pressure nip.
17. The apparatus according to claim 1, wherein said wraparound
region extends in an angular range of 45.degree. to
120.degree..
18. The apparatus according to claim 1, wherein said wraparound
region extends in an angular range of between 80.degree. and
100.degree..
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of PCT application No.
PCT/EP2011/062196, entitled "APPARATUS FOR PRODUCING A MATERIAL
WEB", filed Jul. 18, 2011, which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an apparatus for producing a
fibrous web, in particular a tissue, paper or cardboard web, having
a forming section and a dryer section, whereby the dryer section
comprises a pressure nip formed by a suction roll and a press roll,
a drying cylinder and a transfer pressure nip which is positioned
downstream from the pressure nip for transferring the fibrous web
to the drying cylinder, whereby the fibrous web together with a
clothing wraps around the suction roll in a wraparound region in
such a way that the clothing is positioned between the suction roll
and the fibrous web.
[0004] 2. Description of the Related Art
[0005] Apparatuses of this type are known. Document EP2090691 A1
discloses a device for the production of tissue webs. Here, the
tissue web is carried on a textured fabric through a pressure nip
which is formed by a suction roll and a press roll; the web is
dewatered and directed to the transfer nip to be transferred to the
Yankee drying cylinder. This provides a compact press
arrangement.
[0006] What is needed in the art is a solution for the production
of a fibrous web with a view to economical energy utilization at
the same or improved quality.
SUMMARY OF THE INVENTION
[0007] The present invention provides an apparatus for producing a
fibrous web, in particular a tissue, paper or cardboard web, having
a forming section and a dryer section, whereby the dryer section
includes a pressure nip formed by a suction roll and a press roll,
a drying cylinder and a transfer pressure nip which is positioned
downstream from the pressure nip for transferring the fibrous web
to the drying cylinder, whereby the fibrous web together with a
clothing wraps around the suction roll in a wraparound region in
such a way that the clothing is positioned between the suction roll
and the fibrous web, characterized in that the wraparound region is
located upstream of the pressure nip and a heating device is
assigned directly to the fibrous web in the wraparound region.
[0008] According to the invention, the wraparound region is located
upstream of the pressure nip and a heating device is assigned
directly to the fibrous web in the wraparound region.
[0009] The advantage of this arrangement is in that the fibrous web
is heated already before the pressure nip in the region of the
suction roll, thereby achieving easier dewaterability. The fibrous
web which still has a high water content is hereby already
gently--that is at low dewatering pressure--dewatered by the vacuum
of the suction roll. As a result important quality parameters, for
example the specific volume which is also referred to as bulk and
the texture of the fibrous web are not impaired. The heated fibrous
web can also be more easily dewatered mechanically in the
subsequent pressure nip. This results in a higher dry content
before the heated drying cylinder, which is preferably in the
embodiment of a Yankee cylinder. Less energy is hereby required for
the less efficient thermal drying than is required with otherwise
the same conditions.
[0010] The clothing is routed preferably through the forming
section and through the drying section. The fibrous web is carried
on said clothing until it is transferred to the drying cylinder.
This renders the apparatus very simple and cost effective in its
design. In addition it is advantageous if the fibrous web is formed
already on the textured fabric. This provides it with a stable
spatial structure.
[0011] In one design variation the Yankee drying cylinder is the
only drying cylinder. After having been transferred to the Yankee
drying cylinder the fibrous web is dried. It is subsequently
removed by means of a creping doctor and wound onto a reel.
[0012] In one preferred design example the clothing is provided by
a permeable textured fabric. Textured fabrics are already known.
They are frequently used in through air drying (TAD) tissue
machines. The texture of the textured fabric utilized for the
invention is arranged so that a texturing effect occurs in regard
to the fibrous web. The specific volume is thereby increased and
the functional characteristics of the produced fibrous web--for
example the water absorption capacity, the water absorption speed
and hand feel--are improved.
[0013] In an additional design variation of the invention the
suction roll is partially wrapped by an inside felt which is
positioned between the clothing and the suction roll. This produces
a soft, volume-protective press nip. Moreover, the water which is
removed from the fibrous web is being evenly distributed to the
suction bores in the roll shell.
[0014] In an additional variation it is possible that the inside
felt is also routed through the transfer nip.
[0015] Moreover it is advantageous if the inside felt is more
compressible than the clothing. Thus the inside felt changes its
thickness at a certain pressure load more than the clothing. This
has a compensative effect, particularly in the pressure nip and
possibly also in the transfer nip. Pressure spikes which could
compromise the fibrous web can thereby be reduced or even avoided.
It is also advantageous if the inside felt has a greater
capillarity than the clothing. This counters remoistening of the
fibrous web.
[0016] According to an additional practical advancement the
clothing is provided by a water-absorbing felt. This is
advantageous, particularly in the production of tissue webs having
a low specific volume and high rate of production. In this case,
the inside felt can be forgone, so that the fibrous web runs
through the pressure nip between the felt which embodies the
clothing and an outside felt which wraps partially around the press
roll.
[0017] In an additional advantageous design variation the heating
device is provided by a steam blow box, hot air pressure hood or a
hot air blower hood. This has the advantage that the steam or the
hot air flows through the fibrous web due to the vacuum in the
suction roll, thereby being able to achieve effective heating of
the fibrous web. The heating device preferably has a direct, in
other words immediate influence upon the fibrous web. The surface
of the fibrous web is exposed in the region of the heating device
and not covered by a clothing.
[0018] It is also conceivable that the heating device is in the
embodiment of an infrared or microwave emitter. In this case the
fibrous web is primarily heated. Only heated ambient air flows
through the fibrous web.
[0019] According to a preferred design variation the suction roll
features a suction box in the region of the wraparound region
and/or in the region of the pressure nip and/or after the pressure
nip, providing suction zones. The suction box can thus be divided
into three suction zones which can be controlled or adjusted
independently in regard to the pressure. The first suction zone is
essentially allocated to the wraparound region of the suction roll
before the pressure nip, whereas the second suction zone is located
in the region of the pressure nip. The third suction zone is
located following the pressure nip and serves the conditioning or
dewatering of the inside felt.
[0020] In an additional advantageous design form the distance
between the forming section and the drying section is greater than
the transfer distance formed by the distance between the pressure
nip and the transfer nip. Because of the short transfer distance
severe cooling of the fibrous web which was heated by the heating
device is avoided and the thermal energy of the downstream drying
cylinder can be used almost completely for drying without having to
first heat the fibrous web.
[0021] In one practical design version the transfer distance is
shorter than 3 m, in particular shorter than 2 m, preferably
shorter than 1.5 m.
[0022] The press roll is advantageously partially wrapped by an
outside felt. The outside felt is also softer than the textured
fabric. The fibrous web is thereby pressed uniformly and
independently of the transferred structure.
[0023] In one practical preferred design variation the clothing and
the fibrous web are routed together through the transfer nip.
[0024] According to an additional embodiment the wraparound region
extends in an angular range of 45.degree. to 120.degree.,
preferably between 80.degree. and 100.degree..
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 embodiments of the invention taken
in conjunction with the accompanying drawings, wherein:
[0026] FIG. 1 is a possible design form of an inventive apparatus;
and
[0027] FIG. 2 is a sectional view of the drying section of the
apparatus.
[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] FIG. 1 illustrates apparatus 1 in the embodiment of a tissue
machine, with the exception of the winder. In forming section 24
the fibrous suspension is fed through a headbox 3 into the nip
which is formed by the outside fabric 4 and clothing 5. Outside
fabric 4 and clothing 5 together partially wrap around a forming
roll 6. The fibrous stock suspension is thereby dewatered and
fibrous web 2 is formed and following the forming section 24 is
carried on clothing 5 to and through a segment of the dryer section
25. This comprises a wraparound region 19 around a suction roll 10,
a pressure nip 14, a transfer pressure nip 15 and a drying cylinder
9 which is in the embodiment of a Yankee drying cylinder with a
large diameter, for example in the range of 3 to 6 m. In this
example, clothing 5 is in the embodiment of a textured fabric. In
this case suction roll 10 is additionally wrapped by an inside felt
8, 8' which is positioned inside the loop of textured fabric 5.
This inside felt 8 is fed preferably only through pressure nip 14.
It is however also optionally possible to feed inside felt 8'
through transfer pressure nip 15. Through pressure nip 14 which is
formed by suction roll 14 and press roll 11 an outside felt 7 is
led around press roll 11, whereby it is in contact with fibrous web
2. After pressure nip 14, fibrous web 2 is led to transfer pressure
nip 15 and is separated from the textured fabric and transferred to
the hot surface of the heated Yankee drying cylinder 9. There, a
further increase of the dry content in fibrous web 2 occurs through
contact drying. Subsequently it is removed by a crepe doctor 26
from Yankee drying cylinder 9 and is fed to a winder station.
Yankee drying cylinder 9, press roll 11 and transfer pressure roll
12 respectively are equipped with their own drive (21, 22, 23). The
arrangement of drying section 25 distinguishes itself by its
compactness. Pressure nip 14, suction roll 10, press roll 11 and
transfer pressure roll 12 are located below Yankee drying cylinder
9. This provides for a very short structural length. This is
especially advantageous when converting existing tissue machines to
an energy efficient concept. In a second design version of the
tissue machine, the textured fabric 5 is replaced by a felt. In
this case the inside felt 8, 8' is omitted.
[0030] FIG. 2 illustrates an enlarged segment of a section of
drying region 25 in FIG. 1. At the beginning of drying region 25
the wraparound region 19 is provided in the region of a suction
roll 10, followed by pressure nip 14 which is formed by suction
roll 19 and a press roll 11. Textured fabric 5 is led together with
fibrous web 2 over wraparound region 19 so that clothing 5 is
positioned between suction roll 10 and fibrous web 2. The outer
side of fibrous web 2 is thereby exposed and not covered. A heating
device 17 which directly influences and heats fibrous web 2 is
provided in this region. The current example shows a steam blow box
17 which directly supplies the surface of fibrous web 2 with steam.
Due to the prevailing vacuum of suction roll 19 steam is drawn
through fibrous web 2 into the suction roll. The fibrous web 2 is
thereby heated, not only on its surface but also in its mass.
Wraparound region 19 represents a heating and flow-through zone in
which fibrous web 2 is already being dewatered and heated, thereby
improving dewatering in press nip 14. Transfer section 18 between
pressure nip 14 and transfer pressure nip 15 is very short. Severe
cooling of fibrous web 2 before the transfer pressure nip is
thereby avoided. Transfer section 18 in this example is 2 m long.
Wraparound region 19 of suction roll 10 is between 45.degree. and
120.degree.. In the existing example it is approximately
90.degree.. Pressure nip 14 is preferably arranged so that the
direction of travel of the fibrous web progresses essentially
vertically in upward direction. A first suction zone 16.1 of the
suction box of suction roll 10 is assigned to transfer region 19
and a second suction zone 16.2 is assigned to pressure nip 14. In
this example, inside felt 8 is separated from textured fabric 5
after passing through pressure nip 14 in the region of a third
suction zone 16.3 and fed to a conditioning device which is not
illustrated here. In a second design variation of the invention a
felt, for example a press felt is used in place of the textured
fabric 5. In this case the inside felt 8, 8' and the third suction
zone 16.3 are omitted, and felt 5' is removed from fibrous web 2
after transfer pressure nip 15 so that the Yankee drying cylinder
is no longer wrapped. This is however the case when using a
textured fabric 5. Press roll 11 and transfer pressure roll 12 are
preferably identical in construction. This saves stocking of a
spare roll. They are designed preferably with a grooved and/or
blind drilled U-cover. They may also be in the embodiment of a
solid shell press roll, deflection roll with flexible cover or as a
shoe roll for formation of an extended pressure nip. A conditioning
device with tube suction device and shower is assigned to each
fabric and felt respectively.
[0031] 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.
COMPONENT IDENTIFICATION LIST
[0032] 1 Apparatus [0033] 2 Fibrous web [0034] 3 Headbox [0035] 4
Outside fabric [0036] 5 Textured fabric, felt [0037] 5' Felt [0038]
6 Forming roll [0039] 7 Outside felt [0040] 8 Inside felt [0041] 8'
Inside felt [0042] 9 Yankee drying cylinder [0043] 10 Suction roll
[0044] 11 Press roll [0045] 12 Transfer pressure roll [0046] 13
Guide roll [0047] 14 Pressure nip [0048] 15 Transfer pressure nip
[0049] 16 Suction box [0050] 16.1 First suction zone [0051] 16.2
Second suction zone [0052] 16.3 Third suction zone [0053] 17
Heating device, blow box [0054] 18 Transfer section [0055] 19
Wraparound region, wraparound angle [0056] 20 Catch pan [0057] 21
Drive [0058] 22 Drive [0059] 23 Drive [0060] 24 Forming section
[0061] 25 Drying section [0062] 26 Creping doctor
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