U.S. patent application number 12/456319 was filed with the patent office on 2009-12-17 for device and process for transferring a material web.
Invention is credited to Klaus Gissing, Michael Janosch, Roland Schick.
Application Number | 20090308556 12/456319 |
Document ID | / |
Family ID | 41037673 |
Filed Date | 2009-12-17 |
United States Patent
Application |
20090308556 |
Kind Code |
A1 |
Gissing; Klaus ; et
al. |
December 17, 2009 |
Device and process for transferring a material web
Abstract
A device for transferring a material web, particularly a web
made of paper, board, tissue, or other pulp. In order to transfer
the material web and, preferably, a supporting belt from a first
supporting surface to a subsequent supporting surface, a pick-up
zone to lift the material web off the first supporting surface and
a stabilizing zone to stabilize the material web are arranged
before the subsequent supporting surface, where vacuum can be
applied to the pick-up zone and the stabilizing zone from one
vacuum source each. Here, the pick-up zone is sub-divided into at
least two pick-up sub-zones across the material web running
direction, where the vacuum can be switched on separately in at
least one pick-up sub-zone. This invention also relates to a
process for transferring a material web performed with the device
according to the invention.
Inventors: |
Gissing; Klaus;
(Judendorf-Strassengel, AT) ; Schick; Roland;
(Graz, AT) ; Janosch; Michael; (Jennersdorf,
AT) |
Correspondence
Address: |
ALIX YALE & RISTAS LLP
750 MAIN STREET, SUITE 1400
HARTFORD
CT
06103
US
|
Family ID: |
41037673 |
Appl. No.: |
12/456319 |
Filed: |
June 15, 2009 |
Current U.S.
Class: |
162/202 ;
162/289 |
Current CPC
Class: |
D21F 5/042 20130101;
D21G 9/0063 20130101 |
Class at
Publication: |
162/202 ;
162/289 |
International
Class: |
D21F 11/00 20060101
D21F011/00; D21G 9/00 20060101 D21G009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 17, 2008 |
AT |
A 962/2008 |
Claims
1. A device for transferring a material web from a first supporting
surface to a subsequent supporting surface, the device comprising:
a pick-up zone adapted to lift the material web off the first
supporting surface, the pick-up zone being connected to a vacuum
source and being limited by first and second sealing mechanisms,
the pick-up zone being sub-divided into at least two pick-up
sub-zones across a material web running direction, where the vacuum
can be switched on separately in at least one pick-up sub-zone; and
a stabilizing zone disposed proximate to the subsequent supporting
surface, the stabilizing zone connected to a vacuum source and
being limited by the second sealing mechanism and a seal,
respectively, and the subsequent supporting surface.
2. The device of claim 1, wherein the pick-up zone is sub-divided
into 3 to 8 pick-up sub-zones.
3. The device of claim 2, wherein the pick-up zone is sub-divided
into 4 to 6 pick-up sub-zones.
4. The device of claim 1, further comprising a damper provided to
switch on the vacuum in at least one connecting duct linking an
associated pick-up sub-zone with a vacuum source.
5. The device of claim 1, further comprising a setting damper
mounted in a connecting duct linking an associated pick-up sub-zone
with a vacuum source.
6. The device of claim 1, wherein the individual pick-up sub-zones
are connected to the same vacuum source.
7. A process for transferring a material web from a first
supporting surface to a subsequent supporting surface, the process
comprising: lifting the material web off the first supporting
surface in a pick-up zone using vacuum, the pick-up zone being
sub-divided into at least two pick-up sub-zones across a material
web running direction, the vacuum being applied separately to the
pick-up sub-zones; and stabilizing the material web before the
subsequent supporting surface in a stabilizing zone using
vacuum.
8. The process of claim 7, further comprising setting or adjusting
the vacua in the pick-up sub-zones independently of one
another.
9. The process of claim 7, further comprising applying vacuum to
the pick-up sub-zones separately from one another when widening the
material web.
10. The process of claim 9, wherein only those pick-up sub-zones
over which the material web passes being placed under vacuum.
Description
BACKGROUND
[0001] This invention relates to a device for transferring a
material web, particularly a web made of paper, board, tissue, or
other pulp. In order to transfer the material web and, preferably,
a supporting belt from a first supporting surface to a subsequent
supporting surface, the device includes a pick-up zone to lift the
material web off the first supporting surface and a stabilizing
zone to stabilize the material web before the subsequent supporting
surface, where the pick-up zone is limited by sealing mechanisms
and the stabilizing zone is limited by a sealing mechanism and a
seal, respectively, together with the subsequent stabilizing zone.
A vacuum can be applied to the pick-up zone and stabilizing zone
from one vacuum source each. This invention also relates to a
process for transferring a material web performed with the device
according to the invention.
[0002] Devices of this kind for web transfer are used in the dryer
section of paper machines, for example. These dryer sections
usually consist of a number of drying cylinders and suction rolls,
each of which are arranged in a row. The material web to be dried,
supported in a meandering path by an air-permeable supporting belt,
runs from a first drying cylinder to a suction roll and then to a
further drying cylinder again. Here, the web must be transferred in
the areas between the drying cylinders and the suction rolls. This
transfer is effected using special web transfer devices.
[0003] Patent application EP 1 788 153 A2, for example, describes a
web transfer box with a pick-up zone and a stabilizing zone. In the
pick-up zone, the material web and the supporting belt are lifted
off the drying cylinder with the aid of vacuum, and in the
stabilizing zone that immediately follows, the material web and
supporting belt are stabilized by means of vacuum before being
transferred to the suction roll. The two vacua in the pick-up zone
and the stabilizing zone can be set and adjusted separately in this
process.
[0004] It is known from the above mentioned EP 1 788 153 A2, among
others, that a tail transfer area can be defined in the stabilizing
zone at the side edge by means of an air knife. The advantage here
is that the transfer vacuum can be increased in the tail transfer
area when a tail is transferred, however, this division only
applies to the stabilizing zone. The disadvantage here is that
vacuum is always applied to the pick-up zone over its entire length
across the material web running direction, particularly when the
web is being widened. Widening of the web is the process step in
which a narrow transfer tail of the material web is widened in
stages until the material web has reached the final width required
in production. This step is required when starting up a dryer
section or after a web break because a full-width material web
cannot be threaded in between the drying cylinders and the suction
rolls over the entire production width.
[0005] Due to the difference between the width of the material web
and the width of the pick-up zone when threading in and when
widening the web, the vacuum level in the pick-up zone covered by
the material web is maintained unnecessarily. This generates high
energy costs. In most cases, the vacuum level in the overall system
deteriorates, which has a negative influence on functionality.
SUMMARY
[0006] The problem thus addressed by the present invention is to
create a web transfer device and a transfer process that allows
improved web transfer when threading in the web tail and when
widening the web.
[0007] This problem is solved by a device in which the transfer
zone is sub-divided into at least two pick-up sub-zones across the
material web running direction, where the vacuum can be switched on
separately in at least one pick-up sub-zone. The pick-up zone is
sub-divided preferably into 3 to 8 or 4 to 6 pick-up sub-zones.
[0008] By sub-dividing the pick-up zone, the sub-zone of the
pick-up box to which vacuum is applied can be adapted optimally to
the material web width, particularly during widening.
[0009] In an advantageous embodiment of the invention, a damper to
switch on the vacuum is provided in at least one connecting duct
linking a pick-up sub-zone with a vacuum source.
[0010] A damper allows the respective pick-up sub-zone to be
switched on promptly.
[0011] The individual vacua can also be set here by means of a
setting damper that is also mounted in a connecting duct. This type
of setting damper is a simple and low-cost structure that can be
replaced easily in the event of a fault. By mounting it in a
connecting duct, the setting damper is easy to access and to
actuate.
[0012] Advantageously, the individual pick-up sub-zones should be
connected to the same vacuum source as this is cheaper. It is also
possible, however, to apply the vacuum for the individual pick-up
sub-zones using several vacuum sources, which can be smaller in
dimension as a result.
[0013] The invention also relates to a corresponding process for
transfer of a material web, where vacuum is applied separately to
pick-up sub-zones arranged across the material web running
direction in the pick-up zone.
[0014] This process allows optimum adaptation of the pick-up zone
to the current material web width.
[0015] Advantageously, the vacua in the pick-up sub-zones can be
set or adjusted independently of one another. This ensures that the
material web is lifted off the first supporting surface at the
tangent point.
[0016] In an advantageous embodiment of the process, vacuum is
applied to the pick-up sub-zones separately from one another when
widening the material web. In addition to threading in the transfer
tail, it is advantageous to adapt the pressure in the individual
pick-up sub-zones during the widening process in order to create an
adequate vacuum level.
[0017] Here, it is also useful if only those pick-up sub-zones over
which the material web passes are placed under vacuum.
[0018] There would be no point in applying vacuum to pick-up
sub-zones that the material web does not pass over, for example
because it has not yet reached its final width. This would only be
a waste of suction output from the vacuum source.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present disclosure may be better understood and its
numerous objects and advantages will become apparent to those
skilled in the art by reference to the accompanying drawings in
which:
[0020] FIG. 1 is a schematic side view of a web transfer device
according to the invention;
[0021] FIG. 2 is a schematic view from above of the web transfer
device according to the invention;
[0022] FIG. 3 is a view of the web transfer device from above
during threading in of the transfer tail and widening of the
material web; and
[0023] FIG. 4 is a schematic diagram of a further web transfer
device according to the invention.
DETAILED DESCRIPTION
[0024] The web transfer device 5 according to the invention is
shown in FIG. 1. It can comprises a pick-up box 5 and a stabilizing
box 7, however it is also conceivable that it comprises only one
web transfer box. During operation, a material web 1, coming from
the right, is supported on a supporting belt 2 and guided over a
first supporting surface 3, which is a rotating and heated drying
cylinder in the present example. Then the material web 1 and the
supporting belt 2 are lifted off the first supporting surface 3 in
the pick-up zone 6. For this purpose, a vacuum is applied to the
pick-up zone 6, causing the material web 1 and the supporting belt
2 to be lifted off the first supporting surface 3 by suction. The
pick-up zone 6 is sealed off by means of sealing mechanisms 10 and
10' that run across the machine running direction. The pick-up zone
6 is adjoined by a stabilizing zone 8. In this stabilizing zone 8,
the material web 1 and the supporting belt 2 are stabilized by
means of vacuum. The stabilizing zone 8 is separated from the
pick-up zone 6 by the seal 10'. There may also be a further zone 9,
however, between the pick-up zone 6 and the stabilizing zone 8. In
this case, this additional zone 9 is limited by the sealing
mechanism 10 and the seal 14 across the material web running
direction. This additional zone 9 must not necessarily be under
vacuum, but can also be open to the machine environment at ambient
pressure.
[0025] If the additional zone 9 is available, the stabilizing zone
is sealed off by the seal 14 across the machine running direction
19.
[0026] FIG. 2 shows the web transfer device in a schematic view
from above. The reference numerals used in all figures refer to the
same items. The figure clearly shows how the pick-up zone 6 is
divided into pick-up sub-zones 11, 12, 13 according to the
invention. In the present example, the pick-up zone is divided into
three pick-up sub-zones 11, 12, 13, where the first pick-up
sub-zone 11 is narrower than the second pick-up sub-zone 12. The
third pick-up sub-zone 13 is broader than the second pick-up
sub-zone 12. The split into 3 pick-up sub-zones is only shown as an
example, and it would also be possible to divide the pick-up zone
into 2, 4 or more sub-zones. Pick-up sub-zones 11, 12 and 13 can
all be the same width or can have different widths, as in the
example shown. The pick-up zone 6, and thus also the pick-up
sub-zones 11, 12 and 13, can be placed under vacuum from a vacuum
source. The flow direction of the air extracted is shown
schematically by the flow direction arrows 20. The pick-up
sub-zones are each connected via a connecting duct 18 to a suction
pipe 24 through which the air from the individual pick-up sub-zones
11, 12 and 13 is extracted by suction.
[0027] The vacuum in the individual pick-up sub-zones 11, 12 and 13
can be switched on using the damper 16, and set or adjusted using
the setting damper 15. The dampers 16 and setting dampers 15 are
located in the connecting duct 18.
[0028] FIG. 3 shows the web transfer device according to the
invention during the tail threading process and during widening of
the material web 1. In the tail threading process, only a narrow
strip (tail) of the material web 1 is transferred to the web
transfer device. This narrow strip of the material web 1 is limited
by the material web edges a and b. The dampers 16 in the second
pick-up sub-zone 12 and the third pick-up sub-zone 13 are closed.
In this way, only the first pick-up sub-zone 11 is placed under
vacuum from the vacuum source 17. As soon as the tail has been
threaded in completely, the material web 1 can be widened. In this
process, the material web width increases continuously until it has
reached the final width as shown by the material web edges a and d.
Material web edge c shows the material web 1 during the widening
process.
[0029] In order to widen the material web 1, vacuum is applied only
to those pick-up sub-zones 12, 13 over which the material web 1
passes. Thus, damper 16 in the second pick-up sub-zone 12 is opened
when widening begins, setting this zone under vacuum. This
guarantees that the part of the material web 1 passing over the
second pick-up sub-zone is received reliably by the first
supporting surface 3. As long as the material web 1 only passes
over the first and second pick-up sub-zones 11 and 12, the damper
16 in the third pick-up zone 13 remains closed. This zone is not
placed under vacuum until the material web is wide enough and thus,
also passes over the third pick-up sub-zone 13. In this way, vacuum
is only applied to those pick-up sub-zones 11, 12, 13 where a
vacuum is actually needed to pick up the material web. The dampers
16 can be provided with an automatic control device that opens or
closes the dampers depending on the material web width.
[0030] FIG. 4 shows a schematic diagram of a further web transfer
device according to the invention. Here, not only the pick-up zone
6, but also the stabilizing zone is sub-divided into several
stabilizing sub-zones 21, 22 and 23. These stabilizing sub-zones
are also adjustable by means of setting dampers 15', preferably
separately from one another. The second stabilizing zone 22 and the
third stabilizing zone 23 can be placed under vacuum from the
additional vacuum source 17' by means of the dampers 16'. The
stabilizing sub-zones 22 and 23 are switched on by means of the
dampers 16' during widening in the same way as the dampers 16 are
switched on in the pick-up sub-zones 12 and 13. In the example
shown, the pick-up zone 6 and the stabilizing zone 8 are separated
from one another by an additional zone 9. This additional zone 9 is
separated from the pick-up zone 6 and the stabilizing zone 8 by the
sealing mechanism 10' and the seal 14, respectively. The pick-up
zone 6 and the stabilizing zone 8 can, of course, also be placed
directly adjacent to one another.
[0031] The embodiments in the drawings only show one preferred
embodiment of the invention. The invention also relates to other
embodiments in which, for example, the pick-up zone 6 or the
stabilizing zone 8 is divided into more than three sub-zones. It is
also conceivable that the stabilizing zone 8 is divided into other
stabilizing sub-zones 21, 22, 23 than the pick-up zone. Similar to
the pick-up sub-zones, the stabilizing sub-zones can also be
switched on or adjusted separately.
[0032] It will be appreciated that various of the above-disclosed
and other features and functions, or alternatives thereof, may be
desirably combined into many other different systems or
applications. Also that various presently unforeseen or
unanticipated alternatives, modifications, variations or
improvements therein may be subsequently made by those skilled in
the art which are also intended to be encompassed by the following
claims.
* * * * *