U.S. patent application number 09/982175 was filed with the patent office on 2002-05-09 for shoe press.
This patent application is currently assigned to VOITH PAPER PATENT GmbH. Invention is credited to Meschenmoser, Andreas.
Application Number | 20020053415 09/982175 |
Document ID | / |
Family ID | 26007562 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020053415 |
Kind Code |
A1 |
Meschenmoser, Andreas |
May 9, 2002 |
Shoe press
Abstract
Shoe press and press section including shoe press for processing
a fibrous material web that includes two shoe press units arranged
to form an essentially level press nip elongated in a web travel
direction. Each of the two shoe press units include a circulating
flexible, continuous sealing belt and a press shoe, such that the
circulating flexible, continuous sealing belt is arranged to be
guided over the press shoe in a region of the press nip. At least
two driven continuous press belts are arranged such that at least
one of the at least two driven continuous press belts are
positioned on each side of the fibrous material web to guide the
fibrous material web through the press nip.
Inventors: |
Meschenmoser, Andreas;
(Horgenzell, DE) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1941 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
VOITH PAPER PATENT GmbH
Heidenheim
DE
|
Family ID: |
26007562 |
Appl. No.: |
09/982175 |
Filed: |
October 19, 2001 |
Current U.S.
Class: |
162/358.1 ;
162/358.3 |
Current CPC
Class: |
D21F 3/0218
20130101 |
Class at
Publication: |
162/358.1 ;
162/358.3 |
International
Class: |
D21F 003/04; D21F
003/08; D21F 003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 3, 2000 |
DE |
100 54 674.9 |
Jan 12, 2001 |
DE |
201 00 509.3 |
Claims
What is claimed:
1. A shoe press for processing a fibrous material web, comprising:
two shoe press units arranged to form an essentially level press
nip elongated in a web travel direction; each of said two shoe
press units comprising a circulating flexible, continuous sealing
belt and a press shoe, such that said circulating flexible,
continuous sealing belt is arranged to be guided over said press
shoe in a region of said press nip; and at least two driven
continuous press belts arranged such that at least one of said at
least two driven continuous press belts are positioned on each side
of the fibrous material web to guide the fibrous material web
through said press nip.
2. The shoe press in accordance with claim 1, wherein said fibrous
material web comprises one of a paper and a cardboard web.
3. The shoe press in accordance with claim 1, wherein each of said
at least two press belts comprise a dewatering belt.
4. The shoe press in accordance with claim 1, further comprising at
least two felts arranged on opposite sides of the fibrous material
web, whereby said press nip comprises a double-felted press nip,
wherein said at least two felts are arranged between said press
belts, such that said at least two felts are guided substantially
horizontally through said press nip together with the fibrous
material web.
5. The shoe press in accordance with claim 1, wherein at least one
of said two shoe press units comprises a shoe press roll and said
sealing belt comprises a jacket of said shoe press roll.
6. The shoe press in accordance with claim 1, wherein a press plane
through said press nip is inclined in relation to a vertical
reference.
7. The shoe press in accordance with claim 6, wherein said press
plane is inclined in relation to the vertical reference by an angle
(.alpha.) in the region of approximately 10.degree. to
approximately 45.degree..
8. The shoe press in accordance with claim 1, wherein at least one
of said at least two press belts comprises an open press
surface.
9. The shoe press in accordance with claim 7, wherein a press
surface of said at least one press belt is at least one of blind
bored and grooved.
10. The shoe press in accordance with claim 1, wherein at least one
of said at least two press belts comprises a water permeable wire
web.
11. The shoe press in accordance with claim 10, wherein at least
one of said at least two sealing belts comprises an open press
surface that is at least one of blind bored and grooved.
12. The shoe press in accordance with claim 11, wherein said at
least one water permeable wire web press belt and said at least one
open press surface sealing belt are arranged in a same press shoe
unit.
13. The shoe press in accordance with claim 1, further comprising
at least one deflection roll and a collector positioned in a region
of said at least one deflection roll, wherein, subsequent to said
press nip, at least one of said at least two press belts is guided
around said at least one deflection roll, whereby water thrown off
said press belt as it is guided around said at least one deflection
roll is collected in said collector.
14. The shoe press in accordance with claim 13, further comprising
a scraper allocated to said at least one deflection roll.
15. The shoe press in accordance with claim 13, wherein said at
least one deflection roll is driven.
16. The shoe press in accordance with claim 15, further comprising
at least one additional driven deflection roll around which said at
least one press belt is guided.
17. The shoe press in accordance with claim 16, wherein said at
least one deflection roll is structured and arranged as a belt
travel control roll.
18. The shoe press in accordance with claim 1, wherein press
surfaces of said at least two press belts have a same hardness.
19. The shoe press in accordance with claim 1, wherein at least one
of said at least two sealing belts comprises a continuous, smooth
surface.
20. The shoe press in accordance with claim 1, wherein felts with
few markings are guided through said press nip, and said felts are
arranged to cause symmetrical dewatering.
21. The shoe press in accordance with claim 1, wherein, outside of
said press nip, said at least two press belts are guided separately
from said at least two sealing belts.
22. The shoe press in accordance with claim 1, wherein, prior to
said press nip, at least one of said at least two press belts is
guided around a deflection roll structured and arranged as a belt
travel control roll.
23. A press section of a machine for producing a fibrous material
web, comprising: a shoe press including two shoe press units
arranged to form an essentially level press nip elongated in a web
travel direction; each of said two shoe press units comprising a
circulating flexible, continuous sealing belt and a press shoe,
such that said circulating flexible, continuous sealing belt is
arranged to be guided over said press shoe in a region of said
press nip; and each of said two shoe press units comprising at
least one driven continuous press belt, such that at least one
driven continuous press belt is positioned on each side of the
fibrous material web to guide the fibrous material web through said
press nip.
24. The press section in accordance with claim 23, wherein the
fibrous material web comprises at least one of a paper and a
cardboard web.
25. The press section in accordance with claim 23, wherein said
shoe press is the only press.
26. The press section in accordance with claim 23, further
comprising at least two felts arranged on opposite sides of the
fibrous material web, whereby said press nip comprises a
double-felted press nip, wherein said at least two felts are
arranged between said press belts, such that said at least two
felts are guided substantially horizontally through said press nip
together with the fibrous material web.
27. The press section in accordance with claim 23, wherein the
fibrous material web is accepted by one of said at least two felts
from a wire belt.
28. The press section in accordance with claim 27, further
comprising a suctioned guidance roll located in a region of a
transfer position, wherein at least one of said at least two felts
is guided around said suctioned guidance roll.
29. The press section in accordance with claim 27, wherein the
fibrous material web is accepted from the wire belt by an upper
felt.
30. The press section in accordance with claim 27, wherein said at
least two felts are brought together before said press nip and are
subsequently guided to said press nip while sandwiching the fibrous
material web.
31. The press section in accordance with claim 27, further
comprising a suctioned guidance roll arranged downstream, relative
to a web run direction, from said press nip, wherein the fibrous
material web is guided out of said press nip together with said at
least two felts and is subsequently guided together with one of
said at least two felts around said suctioned guidance roll, which
is located in a region in which the fibrous material web is
accepted by another section of the machine.
32. The press section in accordance with claim 31, wherein a drying
wire is guided in the region of said suctioned guidance roll to
accept the fibrous material web from said one felt.
33. The press section in accordance with claim 32, wherein the one
felt comprises a lower felt, such that the fibrous material web is
accepted from said lower felt by the drying wire.
34. The press section in accordance with claim 32, further
comprising another guidance roll arranged to guide said one felt,
wherein the fibrous material web is accepted by the drying wire in
a region between said suctioned guidance roll and said another
guidance roll.
35. The press section in accordance with claim 32, wherein the
drying wire is guided around a suctioned guidance roll in the
region of acceptance.
36. The press section in accordance with claim 27, wherein said at
least two press belts are arranged to be separated immediately
after said press nip from said at least two felts which sandwich
the fibrous material web.
37. A shoe press for processing a fibrous material web, comprising:
first and second shoe press units arranged to form an essentially
level press nip elongated in a web travel direction; said first
shoe press unit comprising a first circulating flexible, continuous
sealing belt and a first press shoe, such that said first
circulating flexible, continuous sealing belt is arranged to be
guided over said first press shoe in a region of said press nip;
said second shoe press unit comprising a second circulating
flexible, continuous sealing belt and a second press shoe, such
that said second circulating flexible, continuous sealing belt is
arranged to be guided over said second press shoe in a region of
said press nip; first and second continuous press belts arranged
such that said first continuous press belt is positioned between
said first press shoe and the fibrous material web, and said second
continuous press belt is positioned between said second press shoe
and the fibrous material web; and first and second press belt
driving devices arranged to drive said first and said second press
belts, respectively.
38. The shoe press in accordance with claim 37, further comprising
first and second felts arranged to sandwich the fibrous material
web.
39. The shoe press in accordance with claim 38, wherein said first
and second felts are arranged between said first and second press
belts.
40. The shoe press in accordance with claim 37, wherein a pressing
plane of said press nip is obliquely oriented in relation to a
vertical reference.
41. The shoe press in accordance with claim 40, wherein said
pressing plane is obliquely oriented at an angle of between about
10.degree. and about 45.degree. from the vertical reference.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C.
.sctn. 119 of German Patent Application Nos. 100 54 674.9 filed
Nov. 3, 2000 and 201 00 509.3 filed Jan. 12, 2001, the disclosures
of which are expressly incorporated by reference herein in their
entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a shoe press for processing
a fibrous material web, in particular a paper or cardboard web,
having two shoe press units between which an essentially level
felted press nip is formed in the web travel direction and having
one circulating flexible continuous sealing belt each guided over
the press shoe in the region of the press nip. The invention
additionally relates to a press section having such a shoe
press.
[0004] 2. Discussion of Background Information
[0005] In each of the previously known double-felted presses known
as TandemNipco-Flex or the UltraNipcoFlex, only one roll is driven.
These known presses have the disadvantage, among other things, that
relatively strong lateral and/or shearing forces occur in the press
nip in the web travel direction. These forces are stronger the
longer the press nip is, and stronger when the felts change their
dimensions due to the wear in the press nip.
[0006] In the case of special paper types and depending on
different drive parameters, the sheet structure can be affected
negatively. The purpose of FIG. 1 is to explain the connection of
the nip stress and a one-sided drive of the shoe press.
[0007] For this purpose, FIG. 1 shows a conventional double-felted
shoe press, driven on one side, in a schematic partial
representation having a shoe press roll 12 provided with a concave
press shoe 10 and a mating roll 14. The flexible press jacket of
the shoe press roll 12 is marked "16." An upper felt 20 and a lower
felt 22 are guided through the press nip 18. The paper web is
positioned between these two felts 20 and 22.
[0008] The two felts 20 and 22 enter into the press nip 18 with the
thickness S1 and/or S2. Together with the rising pressure in the
press nip 18 (compare the pressure progression indicated in the web
travel direction L in the upper part of FIG. 1)k, the corresponding
felt thickness S1 and/or S2 and the corresponding speeds V1 and/or
V2 of the neutral fibers 24 in the corresponding felt 20 and 22
automatically reduce (compare the speed progression indicated in
the web travel direction L in the lower part of FIG. 1), subsequent
to being pressed onto a smaller circumferential radius R' by the
felt compression and being compressed by the sandwich 26 formed by
the felts and the paper web and acting like a spring. Lateral
forces automatically occur in the web travel or machine operating
direction L, which are additionally overlapped by a frictional
force developing on the stationary press shoe 10. Although it is
necessary for the driving force for this conventionally
double-felted shoe press with a concave press shoe to be very high,
it is only driven on one side.
[0009] Therefore, in such known shoe presses, considerable lateral
forces develop between the separate layers mating roll/lower felt,
lower felt/paper, paper/upper felt, upper felt/press jacket, and
press jacket/shoe. The strong lateral force and fulling work
occurring in the entire sandwich package is particularly caused by
the asymmetrical shape change and the different settling
characteristics of the layers. The slippage occurring under high
pressure between the felts in the web travel direction has negative
effects on the sheet structure. Additionally, a paper worn and
compressed in the web travel direction requires a higher stress in
the subsequent sections, such as the drying section.
[0010] A shoe press of the type mentioned at the outset, with an at
least essentially level press nip, is known from DE-A-196 38
689.
SUMMARY OF THE INVENTION
[0011] The present invention provides an improved shoe press and an
improved press section of the type mentioned at the outset in which
the above-mentioned disadvantages are avoided and in which a
technologically optimal product quality is ensured.
[0012] The shoe press according to the invention provides that, on
both sides of the material web, a driven continuous press belt is
additionally guided together with the material web. The two press
belts are each preferably formed by a dewatering belt. The press
nip is preferably double-felted, with both felts guided
horizontally between the two additional press belts together with
the fibrous material web arranged therebetween. Preferably, at
least one of the two shoe press units is formed by a shoe press
roll and the respective sealing belt by the jacket of the shoe
press roll.
[0013] In accordance with an exemplary embodiment of the invention,
the sandwich to be pressed, which includes the fibrous material web
and the felt or felts, can now be guided through the press by the
additionally provided press belts, with a straight guidance now
being possible over an extended distance particularly before and
after the press nip. Accordingly, a pressing practically free of
lateral forces results in the extended press nip of the shoe press.
A targeted pressing in the z-direction results, being similar to
roll presses driven on both sides. Independently of the respective
length of the press nip, lateral forces in the machine direction
are avoided on the fibrous material web, the felts, and the press
jackets. Optimally, a dewatering and web surface on the same side,
a high volume, and a good tenacity are ensured. A separation of
functions results with regard to the sealing of the shoe press
units, and with regard to the dewatering of the nip. Therefore,
optimal design possibilities for the press belts and/or dewatering
belts result with respect to the respective requirements
independently of the sealing function. For example, a smooth,
notch-free sealing belt of a respective shoe press unit is less
susceptible to tears on the surface and can therefore be thinner
and correspondingly more flexible. A separately guided press belt
and/or dewatering belt can be designed more optimally in
correspondingly larger deflection radii with respect to the
corresponding requirements (e.g., press drive and open press
surface). For example, harder grooves and a more stable tensile web
is possible. In particular, an even hardness of the press surface
is possible (same-sided felt markings). In the sealing belts and/or
sealing jackets, the compression and sagging inversion stress is
correspondingly smaller in smooth and/or level shoes. In any case,
it is ensured by the sealing belts that leaking oil does not
directly contact the felts and the fibrous web. Overall, a press
concept results that requires fewer spare rolls.
[0014] In a useful practical embodiment of a shoe press according
to the invention, the press plane through the press nip is inclined
with respect to the vertical. Here, the press plane may be inclined
particularly by an angle in the range of approximately 10 to
approximately 45.degree. with reference to the vertical.
[0015] Preferably, at least one of the two press belts is provided
with an open press surface. This surface may, in particular, be
blind bored and/or grooved. However, it is also possible to form at
least one of the two press belts as a wire web.
[0016] If one or both press belts are embodied in a water permeable
fashion, the corresponding sealing belts, i.e., wrapped thereby,
should be provided with an open surface, i.e., be embodied in a
grooved and/or blind bored fashion, for example. This considerably
increases the dewatering capacity of the arrangement.
[0017] In a preferred practical embodiment, at least one of the two
press belts is guided around a deflection roll subsequent to the
press nip, in the region of which roll a groove is provided in
order to collect the water thrown off the press belt. A doctor or a
scraper can be assigned to the respective deflection roll. It is
also advantageous for the respective deflection roll to be driven.
In general, the respective press belt can be guided around at least
one other driven deflection roll as well.
[0018] In order to keep potential felt markings on the same side,
the press surfaces of the two press belts can be provided with the
same hardness.
[0019] It is also advantageous for at least one of the two sealing
belts of the two shoe press units to be provided with a continuous
smooth surface. A smooth, notch-free sealing belt for sealing the
shoe press unit and/or the shoe press roll is less susceptible to
tears on its surface and, therefore, may be thinner and
correspondingly more flexible as well.
[0020] It is practical for felts with few markings to be guided
through the double-felted press nip, causing a symmetrical
dewatering.
[0021] Outside of the press nip, the press belts are preferably
guided separately from the sealing belts. Therefore, larger
deflection radii are possible for the press belts, which allows a
better optimization with regard to the respective requirements
(press drive, open press surface). Therefore, these press belts may
be provided with harder grooves, for example, or with a more stable
tensile web.
[0022] With regard to the press section, the press section in
accordance with the features of the instant invention includes the
shoe press. Here, this shoe press is preferably the only press in
the press section.
[0023] Advantageously, the two felts of the double-felted shoe
press are already joined before the press nip and subsequently
guided to the press nip together with the fibrous web positioned
therebetween. Advantageously, the fibrous material web is also
guided together with the two felts out of the press nip for a
certain distance. Thus, the sandwich of the fibrous material web
and the two felts to be pressed can be guided straight through the
press, with this sandwich being guided in a straight manner for a
certain distance, in particular prior to and subsequent to the
press nip.
[0024] Subsequent to the press nip, the fibrous material web may be
guided together with one of the two felts around a suctioned
guiding roll, in particular in its region being accepted by a
drying wire, for example.
[0025] The present invention is directed to a shoe press for
processing a fibrous material web that includes two shoe press
units arranged to form an essentially level press nip elongated in
a web travel direction. Each of the two shoe press units include a
circulating flexible, continuous sealing belt and a press shoe,
such that the circulating flexible, continuous sealing belt is
arranged to be guided over the press shoe in a region of the press
nip. At least two driven continuous press belts are arranged such
that at least one of the at least two driven continuous press belts
are positioned on each side of the fibrous material web to guide
the fibrous material web through the press nip.
[0026] According to a feature of the invention, the fibrous
material web can include one of a paper and a cardboard web.
[0027] In accordance with another feature of the instant invention,
each of the at least two press belts may include a dewatering
belt.
[0028] Further, at least two felts can be arranged on opposite
sides of the fibrous material web, whereby the press nip forms a
double-felted press nip. The at least two felts can arranged
between the press belts, such that the at least two felts are
guided substantially horizontally through the press nip together
with the fibrous material web.
[0029] At least one of the two shoe press units may include a shoe
press roll and the sealing belt can include a jacket of the shoe
press roll.
[0030] According to still another feature of the present invention,
a press plane through the press nip can be inclined in relation to
a vertical reference. The press plane may be inclined in relation
to the vertical reference by an angle (.alpha.) in the region of
approximately 10.degree. to approximately 45.degree..
[0031] At least one of the at least two press belts can include an
open press surface. A press surface of the at least one press belt
may be at least one of blind bored and grooved.
[0032] Moreover, at least one of the at least two press belts can
include a water permeable wire web. At least one of the at least
two sealing belts may include an open press surface that is at
least one of blind bored and grooved. The at least one water
permeable wire web press belt and the at least one open press
surface sealing belt can be arranged in a same press shoe unit.
[0033] Still further, at least one deflection roll and a collector
can be positioned in a region of the at least one deflection roll.
Subsequent to the press nip, at least one of the at least two press
belts may be guided around the at least one deflection roll,
whereby water thrown off the press belt as it is guided around the
at least one deflection roll is collected in the collector. A
scraper can be allocated to the at least one deflection roll. The
at least one deflection roll may be driven. At least one additional
driven deflection roll may be provided around which the at least
one press belt can be guided. The at least one deflection roll can
be structured and arranged as a belt travel control roll.
[0034] In accordance with a further feature of the instant
invention, press surfaces of the at least two press belts can have
a same hardness.
[0035] According to a still further feature of the present
invention, at least one of the at least two sealing belts can
include a continuous, smooth surface.
[0036] Moreover, felts with few markings can be guided through the
press nip, and the felts may be arranged to cause symmetrical
dewatering.
[0037] Outside of the press nip, the at least two press belts can
be guided separately from the at least two sealing belts.
[0038] Prior to the press nip, at least one of the at least two
press belts can be guided around a deflection roll structured and
arranged as a belt travel control roll.
[0039] The present invention is directed to a press section of a
machine for producing a fibrous material web. The press section
includes a shoe press including two shoe press units arranged to
form an essentially level press nip elongated in a web travel
direction. Each of the two shoe press units include a circulating
flexible, continuous sealing belt and a press shoe, such that the
circulating flexible, continuous sealing belt is arranged to be
guided over the press shoe in a region of the press nip. Further,
each of the two shoe press units include at least one driven
continuous press belt, such that at least one driven continuous
press belt is positioned on each side of the fibrous material web
to guide the fibrous material web through the press nip.
[0040] According to a feature of the present invention, the shoe
press can be the only press.
[0041] Further, at least two felts can be arranged on opposite
sides of the fibrous material web, whereby the press nip forms a
double-felted press nip. The at least two felts can be arranged
between the press belts, such that the at least two felts are
guided substantially horizontally through the press nip together
with the fibrous material web.
[0042] In accordance with another feature of the instant invention,
the fibrous material web can be accepted by one of the at least two
felts from a wire belt. Further, a suctioned guidance roll can be
located in a region of a transfer position, and at least one of the
at least two felts may be guided around the suctioned guidance
roll. The fibrous material web may be accepted from the wire belt
by an upper felt. Still further, the at least two felts can be
brought together before the press nip and can be subsequently
guided to the press nip while sandwiching the fibrous material web.
Moreover, a suctioned guidance roll may be arranged downstream,
relative to a web run direction, from the press nip, such that the
fibrous material web can be guided out of the press nip together
with the at least two felts and may be subsequently guided together
with one of the at least two felts around the suctioned guidance
roll, which is located in a region in which the fibrous material
web is accepted by another section of the machine. A drying wire
can be guided in the region of the suctioned guidance roll to
accept the fibrous material web from the one felt. Further, the one
felt can include a lower felt, such that the fibrous material web
may be accepted from the lower felt by the drying wire. Further
still, another guidance roll may be arranged to guide the one felt,
and the fibrous material web may be accepted by the drying wire in
a region between the suctioned guidance roll and the another
guidance roll. The drying wire can be guided around a suctioned
guidance roll in the region of acceptance. The at least two press
belts can be arranged to be separated immediately after the press
nip from the at least two felts which sandwich the fibrous material
web.
[0043] The present invention is directed to a shoe press for
processing a fibrous material web that includes first and second
shoe press units arranged to form an essentially level press nip
elongated in a web travel direction. The first shoe press unit
includes a first circulating flexible, continuous sealing belt and
a first press shoe, such that the first circulating flexible,
continuous sealing belt is arranged to be guided over the first
press shoe in a region of the press nip, and the second shoe press
unit includes a second circulating flexible, continuous sealing
belt and a second press shoe, such that the second circulating
flexible, continuous sealing belt is arranged to be guided over the
second press shoe in a region of the press nip. First and second
continuous press belts are arranged such that the first continuous
press belt is positioned between the first press shoe and the
fibrous material web, and the second continuous press belt is
positioned between the second press shoe and the fibrous material
web, and first and second press belt driving devices are arranged
to drive the first and the second press belts, respectively.
[0044] According to a feature of the invention, first and second
felts can be arranged to sandwich the fibrous material web. The
first and second felts may be arranged between the first and second
press belts.
[0045] In accordance with yet another feature of the present
invention, a pressing plane of the press nip can be obliquely
oriented in relation to a vertical reference. The pressing plane
may be obliquely oriented at an angle of between about 10.degree.
and about 45.degree. from the vertical reference.
[0046] Other exemplary embodiments and advantages of the present
invention may be ascertained by reviewing the present disclosure
and the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] The present invention is further described in the detailed
description which follows, in reference to the noted plurality of
drawings by way of non-limiting examples of exemplary embodiments
of the present invention, in which like reference numerals
represent similar parts throughout the several views of the
drawings, and wherein:
[0048] FIG. 1 schematically illustrates a partial representation of
a conventional double-felted shoe press, driven on one side, having
a concave press shoe;
[0049] FIG. 2 schematically illustrates an exemplary embodiment of
a shoe press according to the instant invention which includes a
shoe press according to the instant invention; and
[0050] FIG. 3 schematically illustrates an enlarged schematic
representation of a nip region of the exemplary embodiment of a
shoe press depicted in FIG. 2 with a pressure progression resulting
along the press nip.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0051] The particulars shown herein are by way of example and for
purposes of illustrative discussion of the embodiments of the
present invention only and are presented in the cause of providing
what is believed to be the most useful and readily understood
description of the principles and conceptual aspects of the present
invention. In this regard, no attempt is made to show structural
details of the present invention in more detail than is necessary
for the fundamental understanding of the present invention, the
description taken with the drawings making apparent to those
skilled in the art how the several forms of the present invention
may be embodied in practice.
[0052] FIG. 2 shows a schematic representation of an exemplary
embodiment of a press section 28 according to the invention of a
machine for producing a fibrous material web 30 which may, in
particular, be a paper web or a cardboard web. The press section 28
is provided with a single press, i.e., a shoe press 32 according to
the invention. FIG. 3 shows an enlarged schematic representation of
the nip region of the embodiment of the shoe press according to the
invention shown in FIG. 2. In the upper part of this FIG. 3, the
resulting pressing progression is indicated along the press nip of
the shoe press 32.
[0053] According to FIGS. 2 and 3, the shoe press 32 comprises two
shoe press units 34 and 36 with a press nip 38 formed therebetween
that is at least essentially level and elongated in the web travel
direction L. This press nip 38 is double-felted in the present
case.
[0054] The two shoe press units 34 and 36 are each provided with a
circulating flexible continuous sealing belt 44 and 46, guided over
a press shoe 40 and 42 respectively, in the region of the press nip
38. Additionally, a driven continuous press belt 48, 50
respectively, is guided through the double-felted press nip 38 on
both sides of the fibrous material web 30 each. The two press belts
48 and 50 are each formed by a dewatering belt.
[0055] As is discernible from FIGS. 2 and 3, both an upper felt 52
and a lower felt 54 are provided. Guided horizontally through the
press nip 38 between the two additional press belts 58 and 50, the
two felts 52 and 54 are provided together with the fibrous material
web 30 positioned therebetween.
[0056] In the present exemplary embodiment, the two shoe press
units 34 and 36 are each formed by a shoe press roll, and the
sealing belts 44 and 46 are each correspondingly formed by the
jacket of the respective shoe press roll.
[0057] In order to form the at least essentially even press nip 38,
the two press shoes 40 and 42 are each provided with an at least
essentially level support surface over which the respective sealing
belt 44 and 46 is guided.
[0058] In the present exemplary embodiment, the press plane 56
through the press nip 38 is inclined relative to the vertical 58.
The corresponding angle of incline .alpha. may be in the range of
approximately 10.degree. to approximately 45.degree., for
example.
[0059] The two press belts 48 and 50 are provided with one open
press surface each, allowing a corresponding dewatering. In
particular, these two press belts 48 and 50 may each be blind bored
and/or grooved.
[0060] However, the two press belts 48 and 50 may each be formed by
a water permeable wire web. In this case, the sealing belts 44 and
46 should be provided with an open press surface, i.e., be grooved
or blind bored. This considerably increases the dewatering capacity
and is particularly important in the case of low dry contents prior
to the press and/or in the case of high surface weights.
[0061] Subsequent to the press nip 38, the two press belts 48 and
50 are each guided around the respective deflection roll 60 and 62,
with one groove 64 and 66 each being provided in the region of the
deflection rolls in order to collect the water thrown off the
corresponding press belt 48 and 50. A scraper 68 and 70 may be
allocated to each of the deflection rolls 60 and 62. The two
deflection rolls 60 and 62 are each driven.
[0062] As is discernible from FIG. 2, both the upper press belt 48
and the lower press belt 50 may each be guided around at least one
additional driven deflection roll 72 and 74. This deflection roll
72 and 74 preferably assumes the function of a belt travel control
roll.
[0063] Additionally these two press belts 48 and 50 are each guided
prior to the press nip 38 around a deflection roll 99 and 100. In
general, these deflection rolls 99 and 100 may also assume the
function of a belt travel control roll.
[0064] The press surface of the two press belts 48 and 50 may be
provided with the same hardness. As mentioned above, in the present
case, they are open in order to provide a corresponding dewatering.
Here, they may be blind bored and/or grooved, for example.
[0065] However, the two sealing belts and/or roll jackets 44 and 46
of the two shoe press units 34 and 36 are preferably provided with
a continuous, smooth surface.
[0066] In particular, felts with few markings, causing a
symmetrical dewatering, may be used for the upper felt 52 and the
lower felt 54.
[0067] As is particularly discernible from FIG. 2, the press belts
48 and 50 are guided separately from the sealing belts 44 and 46
outside of the press nip 38.
[0068] As shown in FIG. 3, particularly using the lower press shoe
40 as an example, both a pressing 76 is possible by means of a row
of pistons as well as a pressing 78 by means of two rows of
pistons.
[0069] As implied for the upper press shoe 40 at the position 80,
for example, an oil feeding via pistons or via a shoe is possible
in order to lubricate the regions between the shoe 40 and the
sealing belt 44.
[0070] In the upper part of FIG. 3, the pressure progression P
resulting in the web travel direction L over the elongated flat or
level press nip 38 is implied.
[0071] As is discernible from FIG. 2, the fibrous material web 30
may be accepted by a wire belt 82 through the upper felt 52 in the
present exemplary embodiment. In the transfer region 84, the upper
felt 52 is guided around a suctioned guidance roll 84.
[0072] The two felts 52 and 54 are guided together even before the
press nip 38 in the region of a deflection roll 86, arranged inside
of the loop of the lower felt 54, and, subsequently, are guided
together with the fibrous material web 30 positioned therebetween
to the press nip 38 extending over the distance 1. Subsequently,
the fibrous material web 30 is guided together with the two felts
52 and 54 out of the press nip 38. Here, as is discernible from
FIGS. 2 and 3, the sandwich to be pressed comprising the two felts
52 and 54 and the fibrous material web 30 positioned therebetween
is guided straight through the press, where a straight guidance may
be provided, in particular a certain distance prior to the press
nip 38 and a certain distance after this press nip.
[0073] After the press nip 38 and subsequent to the section of
straight guidance of the subsequent sandwich, the fibrous material
web 30 is guided together with the lower felt 54 around a
suctioned, preferably driven, guidance roll 88, in the region of
which the web is accepted by a drying wire 90, for example, in
order to guide it to the initial drying cylinder 92 of the drying
section.
[0074] In the present case, the fibrous material web 30 is accepted
by the drying wire 90 in the region between the suctioned guidance
roll 88 and another guidance roll 94 allocated to another lower
felt 54.
[0075] In the region of the transfer position 96, the drying wire
90 is guided around a suctioned guidance roll 98.
[0076] In the present case, as is discernible from the two FIGS. 2
and 3, the two press belts 48, 50 are separated from the two felts
52 and 54 and the fibrous material web 30 positioned therebetween
immediately following to the press nip 38.
[0077] It is noted that the foregoing examples have been provided
merely for the purpose of explanation and are in no way to be
construed as limiting of the present invention. While the present
invention has been described with reference to an exemplary
embodiment, it is understood that the words which have been used
herein are words of description and illustration, rather than words
of limitation. Changes may be made, within the purview of the
appended claims, as presently stated and as amended, without
departing from the scope and spirit of the present invention in its
aspects. Although the present invention has been described herein
with reference to particular means, materials and embodiments, the
present invention is not intended to be limited to the particulars
disclosed herein; rather, the present invention extends to all
functionally equivalent structures, methods and uses, such as are
within the scope of the appended claims.
LIST OF REFERENCE CHARACTERS
[0078] 10 concave press shoe
[0079] 12 shoe press roll
[0080] 14 mating roll
[0081] 16 flexible press jacket
[0082] 18 press nip
[0083] 20 upper felt
[0084] 22 lower felt
[0085] 24 neutral fibers
[0086] 26 elastic sandwich
[0087] 28 press section
[0088] 30 fibrous material web
[0089] 32 shoe press
[0090] 34 shoe press unit, shoe press roll
[0091] 36 shoe press unit, shoe press roll
[0092] 38 elongated press nip
[0093] 40 press shoe
[0094] 42 press shoe
[0095] 44 sealing belt, roll jacket
[0096] 46 sealing belt, roll jacket
[0097] 48 press belt
[0098] 50 press belt
[0099] 52 upper felt
[0100] 54 lower felt
[0101] 56 press plane
[0102] 58 vertical
[0103] 60 deflection roll
[0104] 62 deflection roll
[0105] 64 groove
[0106] 66 groove
[0107] 68 scraper
[0108] 70 scraper
[0109] 72 deflection roll
[0110] 74 deflection roll
[0111] 76 pressing with one row of pistons
[0112] 78 pressing with two rows of pistons
[0113] 80 position
[0114] 82 wire belt
[0115] 84 suctioned guidance roll
[0116] 86 deflection roll
[0117] 88 suctioned guidance roll
[0118] 90 drying wire
[0119] 92 drying cylinder
[0120] 94 guidance roll
[0121] 96 transfer position
[0122] 98 suctioned guidance roll
[0123] 99 deflection roll
[0124] 100 deflection roll
[0125] L web travel direction
[0126] l press nip length
[0127] .alpha. angle of incline
* * * * *