U.S. patent application number 09/775628 was filed with the patent office on 2001-08-23 for elastic transfer belt.
This patent application is currently assigned to VOITH PAPER PATENT GmbH. Invention is credited to Mayer, Roland, Vomhoff, Hannes.
Application Number | 20010015268 09/775628 |
Document ID | / |
Family ID | 7631365 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010015268 |
Kind Code |
A1 |
Mayer, Roland ; et
al. |
August 23, 2001 |
Elastic transfer belt
Abstract
Apparatus and process for guiding a fibrous material web,
apparatus includes an elastic transfer belt arranged to transfer
fibrous material web between an acceptance region and a delivery
region, and a delivery element arranged to deliver fibrous material
web to elastic transfer belt. During acceptance of fibrous material
web from delivery element, elastic transfer belt is arranged to
travel at a same speed as or at only a slightly higher speed than
delivery element. An accepting element is arranged to accept
fibrous material web from elastic transfer belt. During delivery of
fibrous material web to accepting element, transfer belt is
arranged to travel with a same speed as or with only a slightly
higher speed than accepting element. Transfer belt is driven or
slowed to be stretched more during delivery of fibrous material web
to accepting element belt than during acceptance of fibrous
material web from delivery element.
Inventors: |
Mayer, Roland; (Heidenheim,
DE) ; Vomhoff, Hannes; (Djursholm, SE) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN
1941 ROLAND CLARKE PLACE
RESTON
VA
20191
|
Assignee: |
VOITH PAPER PATENT GmbH
Heidenheim
DE
|
Family ID: |
7631365 |
Appl. No.: |
09/775628 |
Filed: |
February 5, 2001 |
Current U.S.
Class: |
162/202 ;
162/289 |
Current CPC
Class: |
D21G 9/0063 20130101;
D21F 3/04 20130101; D21F 2/00 20130101 |
Class at
Publication: |
162/202 ;
162/289 |
International
Class: |
D21F 011/00; D21F
001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 2000 |
DE |
100 07 337.9 |
Claims
What is claimed:
1. An apparatus for guiding a fibrous material web in machines for
at least one of producing and processing the fibrous material web,
comprising: an elastic transfer belt arranged to transfer the
fibrous material web between an acceptance region and a delivery
region; a delivery element arranged to deliver the fibrous material
web to said elastic transfer belt, wherein, during acceptance of
the fibrous material web from said delivery element, said elastic
transfer belt is arranged to travel at a same speed as or at only a
slightly higher speed than said delivery element; an accepting
element arranged to accept the fibrous material web from said
elastic transfer belt, wherein, during delivery of the fibrous
material web to said accepting element, said transfer belt is
arranged to travel with a same speed as or with only a slightly
higher speed than said accepting element, wherein said transfer
belt is driven or slowed to be stretched more during delivery of
the fibrous material web to said accepting element belt than during
acceptance of the fibrous material web from said delivery
element.
2. The apparatus in accordance with claim 1, wherein said elastic
transfer belt is arranged in at least one of a region of a press
section for dewatering and a drying section for drying the fibrous
material web.
3. The apparatus in accordance with claim 1, wherein said fibrous
material web comprises one of a paper, cardboard, and tissue
web.
4. The apparatus in accordance with claim 1, further comprising
guide rolls arranged to control speeds of said elastic transfer
belt; at least one of said guide rolls being positioned in, or
subsequently to, a region of delivery of the fibrous material web
by said elastic transfer belt, at least one other guide roll
positioned in, or subsequent to, a region of acceptance of the
fibrous material web by said elastic transfer belt, wherein said at
least one guide roll is arranged to rotate faster than said at
least one other guide roll.
5. The apparatus in accordance with claim 4, wherein at least one
additional roll is positioned in said region of acceptance of the
fibrous material web by said elastic transfer belt has about a same
speed as said at least one other guide roll.
6. The apparatus in accordance with claim 4, wherein said at least
one guide roll is positioned behind, relative to a web travel
direction, said region of delivery of the fibrous material web to
said elastic transfer belt.
7. The apparatus in accordance with claim 1, wherein a speed of
said elastic transfer belt during said acceptance of the fibrous
material web by said elastic transfer belt is about 0.2% to 5.0%
lower than during said delivery of the fibrous material web to said
acceptance element.
8. The apparatus in accordance with claim 7, wherein said speed of
said elastic transfer belt during said acceptance of the fibrous
material web by said elastic transfer belt is about 0.5% to 4.0%
lower than during said delivery of the fibrous material web to said
acceptance element.
9. The apparatus in accordance with claim 1, wherein said elastic
transfer belt is arranged to travels between a press section and a
drying section.
10. The apparatus in accordance with claim 9, wherein the fibrous
material web is continuously guided by at least one roll or belt in
said press section.
11. The apparatus in accordance with claim 1, wherein said elastic
transfer belt is arranged to at least one of accept the fibrous
material web without any open draw from said delivery element and
deliver the fibrous material web without any open draw to said
accepting element.
12. The apparatus in accordance with claim 1, wherein said delivery
element comprises one of a roll and a belt.
13. The apparatus in accordance with claim 12, wherein said
delivery element comprises a press felt.
14. The apparatus in accordance with claim 1, wherein said
accepting element comprises one of a roll and a belt.
15. The apparatus in accordance with claim 14, wherein said
accepting element comprises one of a drying cylinder and a
suctioned roll.
16. The apparatus in accordance with claim 1, wherein said elastic
transfer belt is permeable.
17. The apparatus in accordance with claim 16, further comprising
suction devices arranged on sides of said elastic transfer belt
opposite to the fibrous material web.
18. The apparatus in accordance with claim 1, wherein said elastic
transfer belt has a smooth surface.
19. The apparatus in accordance with claim 18, wherein a guide roll
is arranged to guide said elastic transfer belt, and said guide
roll is positioned between said delivery of the fibrous material
web to said acceptance element and said acceptance of the fibrous
material web from said delivery element.
20. The apparatus in accordance with claim 19, wherein said guide
roll comprises a suctioned roll.
21. A process for guiding a fibrous material web in an apparatus
for at least one of producing and processing the fibrous material
web, the apparatus including an elastic transfer belt, a delivery
element and an accepting element, the process comprising:
transferring, on the elastic transfer belt, the fibrous material
web between an acceptance region and a delivery region; accepting,
on the elastic transfer belt, the fibrous material web from the
delivery element, and driving the elastic transfer belt, during the
accepting of the fibrous material web from the delivery element, to
travel at a same speed as or at only a slightly higher speed than
the delivery element; delivering, by the elastic transfer belt, the
fibrous material web to the accepting element, and driving the
elastic transfer belt, during the delivering of the fibrous
material web to the accepting element, to travel with a same speed
as or with only a slightly higher speed than said accepting
element; and stretching the transfer belt more during the
delivering of the fibrous material web to the accepting element
belt than during the accepting of the fibrous material web from the
delivery element.
22. The process in accordance with claim 21, further comprising
driving the elastic transfer belt in at least one of a region of a
press section for dewatering and a drying section for drying the
fibrous material web.
23. The process in accordance with claim 21, wherein said fibrous
material web comprises one of a paper, cardboard, and tissue
web.
24. The process in accordance with claim 21, wherein the apparatus
further includes guide rolls, such that at least one of the guide
rolls is positioned in, or subsequently to, a region of delivery of
the fibrous material web by the elastic transfer belt, and at least
one other guide roll positioned in, or subsequent to, a region of
acceptance of the fibrous material web by the elastic transfer
belt, and wherein the stretching comprises rotating the at least
one guide roll faster than the at least one other guide roll.
25. The process in accordance with claim 24, wherein at least one
additional roll is positioned in the region of acceptance of the
fibrous material web by the elastic transfer belt, and the process
further comprises driving the at least one additional roll at about
a same speed as the at least one other guide roll.
26. The process in accordance with claim 24, wherein said at least
one guide roll is positioned behind, relative to a web travel
direction, the region of delivery of the fibrous material web to
said elastic transfer belt.
27. The process in accordance with claim 21, wherein a speed of the
elastic transfer belt during the acceptance of the fibrous material
web by the elastic transfer belt is about 0.2% to 5.0% lower than
during the delivery of the fibrous material web to said acceptance
element.
28. The process in accordance with claim 27, wherein the speed of
the elastic transfer belt during the acceptance of the fibrous
material web by the elastic transfer belt is about 0.5% to 4.0%
lower than during the delivery of the fibrous material web to the
acceptance element.
29. The process in accordance with claim 21, further comprising
accepting the fibrous material web on the elastic transfer belt
without any open draw from said delivery element and delivering the
fibrous material web from the elastic transfer belt without any
open draw to the accepting element.
30. The process in accordance with claim 21, wherein the elastic
transfer belt is permeable.
31. The process in accordance with claim 30, further comprising
suctioning sides of the elastic transfer belt opposite to the
fibrous material web.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C.
.sctn. 119 of German Patent Application No. 100 07 337.9, filed on
Feb. 17, 2000, the disclosure of which is expressly incorporated by
reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an elastic transfer belt and
process for guiding a fibrous material web, in particular a paper,
cardboard, or tissue web in machines for producing and/or
processing the same provided in the zone of the press section for
dewatering and/or the subsequent drying section for drying the
fibrous material web.
[0004] 2. Discussion of Background Information
[0005] In the interest of a fibrous material web traveling in a
stable manner, in particular at high speeds, the fibrous material
web is guided, if possible continuously, by at least one roll or
belt. This is particularly important for the press section for
dewatering the fibrous material web and the transition to the
drying section in production machines.
[0006] In the drying section, the fibrous material web travels over
heated drying cylinders guided by drying wires. Here, in
particular, when accepting the moist fibrous material web from the
drying cylinders, tensile stress develops, mainly in the initial
zone of the drying section, thus stretching the fibrous material
web. This is caused by the adhesion of the fibrous material web to
the smooth surface of the drying cylinders which must be designed
in that manner in order to ensure a large, heated contact area and
in order to avoid markings. The stretching of the fibrous material
web can lead to the development of bubbles and folds or even to web
breaks.
SUMMARY OF THE INVENTION
[0007] Therefore, the present invention reduces or even eliminates
the stretching of the fibrous material web in the drying section
while ensuring a secure web guidance.
[0008] The present invention includes a transfer belt traveling at
the same speed as or at an only slightly greater speed than the
delivery element during the acceptance of the fibrous material web
from a delivery element, traveling at the same speed as or at an
only slightly greater speed than the accepting element during the
delivery of the fibrous material web to an accepting element, and
being driven and slowed in such a way that it is stretched more
during the delivery than during the acceptance of the fibrous
material web. This lengthwise stretching direction also leads to a
considerable stretching of the fibrous material web guided by the
transfer belt between the acceptance and the delivery.
[0009] Preferably, this can be achieved, e.g., by driving or
slowing the transfer belt using guiding rolls with at least one
guiding roll, provided in the zone of the delivery of the fibrous
material web or thereafter, rotating faster than at least one
guiding roll provided in the zone of the acceptance of the fibrous
material web or thereafter. With respect to slowing and driving the
transfer belt, the acceptance and delivery is designed to be
relatively simple and secure when a correlating roll in the zone of
the acceptance of the fibrous material web has about the same speed
than the subsequent guiding roll.
[0010] Here, it is essential to realize that the wet fibrous
material web stretches irreversibly in the first tensile stress.
Subsequent tensile stress leads to additional stretching only when
the tensile stress is higher than during the first stretching.
However, the device according to the invention offers the
possibility of stretching the fibrous material web to a relatively
large extent and in a relatively controlled manner in the zone of
the press section as well as at the beginning of the drying section
although the fibrous material web is continuously guided by at
least a belt or a roll.
[0011] This stretching, i.e., the necessary tensile stress
therefor, should be greater than the subsequent tensile stresses in
the drying section, in particular due to the high moisture content
in the initial zone of the drying section. Due to the
above-mentioned special force deformation behavior of the moist
fibrous material web, stretching in the drying section can thus be
avoided or drastically reduced, in particular in the initial
zone.
[0012] For this purpose, the speed of the transfer belt at
acceptance should be lower by about 0.2% to 5.0%, preferably by
about 0.5% to 4.0%, than at delivery of the fibrous material web to
the acceptance element. Additionally, it is advantageous when the
transfer belt travels between the press section and the drying
section, with the transfer belt accepting little or no open draw
from the delivery element and delivering little or no open draw to
the acceptance element. Here, the delivery element should be a roll
or a belt, preferably a belt in the form of a pressed felt as well
as the acceptance element be a roll or a belt, preferably a roll in
the form of a drying cylinder or a suctioned roll. In this case,
the delivery of the fibrous material web is facilitated when the
transfer belt wraps around the drying cylinder or the suctioned
roll.
[0013] In order to design the acceptance, the delivery, and the
transportation of the fibrous material web more securely, the
transfer belt should be permeable. This allows the possibility of
providing suction devices at the acceptance of the fibrous material
web from a press felt as well as subsequently on the side of the
transfer belt opposite of the fibrous material web. If the transfer
belt is redirected at a guide roll between the delivery and
acceptance of the fibrous material web, that guide roll should also
be suctioned. A surface of the transfer belt as smooth as possible
is advantageous for an improved adhesion of the fibrous material
web to the transfer belt.
[0014] The present invention is directed to an apparatus for
guiding a fibrous material web in machines for at least one of
producing and processing the fibrous material web. The apparatus
includes an elastic transfer belt arranged to transfer the fibrous
material web between an acceptance region and a delivery region,
and a delivery element arranged to deliver the fibrous material web
to the elastic transfer belt. During acceptance of the fibrous
material web from the delivery element, the elastic transfer belt
is arranged to travel at a same speed as or at only a slightly
higher speed than the delivery element. An accepting element is
arranged to accept the fibrous material web from the elastic
transfer belt. During delivery of the fibrous material web to the
accepting element, the transfer belt is arranged to travel with a
same speed as or with only a slightly higher speed than the
accepting element. The transfer belt is driven or slowed to be
stretched more during delivery of the fibrous material web to the
accepting element belt than during acceptance of the fibrous
material web from the delivery element.
[0015] According to a feature of the instant invention, the elastic
transfer belt can be arranged in at least one of a region of a
press section for dewatering and a drying section for drying the
fibrous material web. Further, the fibrous material web may include
one of a paper, cardboard, and tissue web.
[0016] In accordance with another feature of the invention, guide
rolls are arranged to control speeds of the elastic transfer belt.
At least one of the guide rolls can be positioned in, or
subsequently to, a region of delivery of the fibrous material web
by the elastic transfer belt, and at least one other guide roll can
be positioned in, or subsequent to, a region of acceptance of the
fibrous material web by the elastic transfer belt. The at least one
guide roll mayh be arranged to rotate faster than the at least one
other guide roll. Further, at least one additional roll can be
positioned in the region of acceptance of the fibrous material web
by the elastic transfer belt has about a same speed as the at least
one other guide roll. Moreover, the at least one guide roll may be
positioned behind, relative to a web travel direction, the region
of delivery of the fibrous material web to the elastic transfer
belt.
[0017] According to still another feature of the present invention,
a speed of the elastic transfer belt during the acceptance of the
fibrous material web by the elastic transfer belt may be about 0.2%
to 5.0% lower than during the delivery of the fibrous material web
to the acceptance element. Further, the speed of the elastic
transfer belt during the acceptance of the fibrous material web by
the elastic transfer belt can be about 0.5% to 4.0% lower than
during the delivery of the fibrous material web to the acceptance
element.
[0018] The elastic transfer belt can be arranged to travel between
a press section and a drying section. The fibrous material web may
be continuously guided by at least one roll or belt in the press
section.
[0019] Further, the elastic transfer belt may be arranged to at
least one of accept the fibrous material web without any open draw
from the delivery element and deliver the fibrous material web
without any open draw to the accepting element.
[0020] The delivery element can include one of a roll and a belt,
and the delivery element can include a press felt.
[0021] The accepting element can include one of a roll and a belt,
and the accepting element can include one of a drying cylinder and
a suctioned roll.
[0022] In accordance with a farther feature of the invention, the
elastic transfer belt may be permeable. Further, suction devices
can be arranged on sides of the elastic transfer belt opposite to
the fibrous material web.
[0023] The elastic transfer belt can have a smooth surface.
Moreover, a guide roll may be arranged to guide the elastic
transfer belt, and the guide roll may be positioned between the
delivery of the fibrous material web to the acceptance element and
the acceptance of the fibrous material web from the delivery
element. The guide roll may include a suctioned roll.
[0024] The present invention is directed to a process for guiding a
fibrous material web in an apparatus for at least one of producing
and processing the fibrous material web, the apparatus including an
elastic transfer belt, a delivery element and an accepting element.
The process includes transferring, on the elastic transfer belt,
the fibrous material web between an acceptance region and a
delivery region, and accepting, on the elastic transfer belt, the
fibrous material web from the delivery element, and driving the
elastic transfer belt, during the accepting of the fibrous material
web from the delivery element, to travel at a same speed as or at
only a slightly higher speed than the delivery element. The process
also includes delivering, by the elastic transfer belt, the fibrous
material web to the accepting element, and driving the elastic
transfer belt, during the delivering of the fibrous material web to
the accepting element, to travel with a same speed as or with only
a slightly higher speed than the accepting element, and stretching
the transfer belt more during the delivering of the fibrous
material web to the accepting element belt than during the
accepting of the fibrous material web from the delivery
element.
[0025] In accordance with a feature of the present invention, the
process can further include driving the elastic transfer belt in at
least one of a region of a press section for dewatering and a
drying section for drying the fibrous material web. Further, the
fibrous material web comprises one of a paper, cardboard, and
tissue web.
[0026] According to another feature of the invention, the apparatus
can further include guide rolls, such that at least one of the
guide rolls is positioned in, or subsequently to, a region of
delivery of the fibrous material web by the elastic transfer belt,
and at least one other guide roll positioned in, or subsequent to,
a region of acceptance of the fibrous material web by the elastic
transfer belt, and the stretching may include rotating the at least
one guide roll faster than the at least one other guide roll. At
least one additional roll can be positioned in the region of
acceptance of the fibrous material web by the elastic transfer
belt, and the process may further include driving the at least one
additional roll at about a same speed as the at least one other
guide roll. The at least one guide roll can be positioned behind,
relative to a web travel direction, the region of delivery of the
fibrous material web to the elastic transfer belt.
[0027] In accordance with still another feature of the present
invention, a speed of the elastic transfer belt during the
acceptance of the fibrous material web by the elastic transfer belt
can be about 0.2% to 5.0% lower than during the delivery of the
fibrous material web to the acceptance element, and the speed of
the elastic transfer belt during the acceptance of the fibrous
material web by the elastic transfer belt is about 0.5% to 4.0%
lower than during the delivery of the fibrous material web to the
acceptance element.
[0028] The process may further include accepting the fibrous
material web on the elastic transfer belt without any open draw
from the delivery element and delivering the fibrous material web
from the elastic transfer belt without any open draw to the
accepting element.
[0029] In accordance with yet another feature of the instant
invention, the elastic transfer belt can be permeable. The process
may further include suctioning sides of the elastic transfer belt
opposite to the fibrous material web.
[0030] 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
[0031] The present invention is further described in the detailed
description which follows, in reference to the noted plurality of
drawings by way of a nonlimiting example of an exemplary embodiment
of the present invention, and wherein:
[0032] The FIGURE schematically illustrates a transition between a
press section and a drying section of a web production and/or
processing machine.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0033] 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.
[0034] In the press section the fibrous material web 1 is guided
through one or several press nips, each formed by two press rolls
10. Here, a press felt 6 travels through each press nip for
accepting the squeezed out water. During the travel of the fibrous
material web 1 through the press section, the fibrous material web
1 is continuously guided by at least one belt or roll, i.e., it
travels in closed tension through the press section. This ensures a
secure travel, in particular even at higher speeds. Here, for
example, one press felt 6 travels on each side of the fibrous
material web 1 with the lower press felt 6, after the separation of
the upper press felt 6 from the fibrous material web 1, acting as a
delivery element 5 and transferring the fibrous material web 1 to
the transfer belt 2.
[0035] The transfer belt 2 is not only embodied elastically but
also smoothly and permeably. The latter allows the arrangement of
suction devices on the side of the transfer belt 2 opposite from
the fibrous material web 1 in order to improve the adhesion to the
transfer belt 2. Here, the transfer belt 2 wraps around a suctioned
guide roll 11 at the acceptance of the fibrous material web 1 from
the delivery element 5. The transfer belt 2 is in a slightly
stretched state in the web travel direction 9 during the acceptance
and travels only slightly faster than the delivery element 5. This
small tension improves the acceptance of the fibrous material
web
[0036] After acceptance, the transfer belt 2 is guided over a guide
roll 8 with a slowing effect. This slowing is necessary because the
guide roll 4 provided subsequent to the delivery of the fibrous
material web 1 travels at a considerably higher speed. Thus, a
relatively strong stretching occurs in the transfer belt 2 and also
in the fibrous material web 1 guided thereby. The guide roll 8
positioned between the acceptance and the delivery of the fibrous
material web 1 is embodied as a suctioned roll for an improved
adhesion of the fibrous material web 1 to the transfer belt 2.
[0037] The acceptance element 3 is a heated drying cylinder 7 and
is wrapped by the transfer belt 2 which enables a frictional
transfer.
[0038] This stretching of the transfer belt 2 between the guide
roll 8 in the middle and the delivery of the fibrous material web 1
should be stronger than any stretching normally to be expected in
the drying section. Therefore, the accepting element 3 rotates at a
speed higher by about 2.0% than the guide roll 8 in the middle.
Since this stretching of the moist fibrous material web 1 is
plastic and can only be increased by an even stronger tensile
stress, as a result, no further stretching need be expected in the
drying section.
[0039] In the drying section, the fibrous material web 1 travels
for the purpose of drying alternately over heated drying cylinders
7 and suctioned guide rolls 14, with the fibrous material web 1
being guided by at least one drying wire.
[0040] In contrast to the usual guide rolls 12 the suctioned guide
rolls or rolls 8, 11, and 14 have a perforated roll jacket whose
inner core is connected to a vacuum source.
[0041] 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.
* * * * *