U.S. patent application number 12/456312 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 | 20090308555 12/456312 |
Document ID | / |
Family ID | 41057741 |
Filed Date | 2009-12-17 |
United States Patent
Application |
20090308555 |
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 includes a transfer
zone to which vacuum can be applied and at least one sealing
mechanism with sealing lips. The sealing mechanism limits or
divides the transfer zone, where suction can be applied to a space
between the sealing lips.
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: |
41057741 |
Appl. No.: |
12/456312 |
Filed: |
June 15, 2009 |
Current U.S.
Class: |
162/202 ;
162/289 |
Current CPC
Class: |
D21F 5/042 20130101;
D21F 5/046 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 961/2008 |
Claims
1. A device for transferring a material web from a first supporting
surface to a subsequent supporting surface, the device comprising a
transfer zone to which vacuum can be applied and at least one
sealing mechanism having a plurality of sealing lips, the sealing
mechanism limiting or dividing the transfer zone, at least two of
the sealing lips defining a space therebetween to which suction can
be applied through an opening.
2. The device of claim 1, further comprising a supporting belt
adapted to support the material web in the transfer zone.
3. The device of claim 1, wherein the sealing lips of the sealing
mechanism form a labyrinth seal.
4. The device of claim 1, wherein the transfer zone comprises a
pick-up zone and a stabilizing zone.
5. The device of claim 4, wherein the sealing mechanism defines the
limit of the pick-up zone.
6. The device of claim 5, wherein the sealing mechanism is disposed
intermediate the pick-up zone and the stabilizing zone.
7. The device of claim 1, wherein the sealing mechanism is
swivel-mounted.
8. A process for transferring a material web from a first
supporting surface to a subsequent supporting surface, the process
comprising applying a vacuum in a transfer zone to transfer the
material web from the first supporting surface to the subsequent
supporting surface; and applying a suction to a sealing mechanism
in the transfer zone.
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, from a first supporting surface, for example a drying
cylinder, to a subsequent supporting surface, for example a suction
roll.
[0002] The device comprises a transfer zone to which vacuum can be
applied and at least one sealing mechanism with sealing lips. This
invention also relates to a process for transferring a material web
performed with the device according to the invention.
[0003] 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 web to be dried, usually
supported in a meandering path by an air-permeable supporting belt,
runs from a first drying cylinder to a suction roll and on to a
further drying cylinder. Here, the web is guided round the suction
roll with the aid of vacuum. 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.
[0004] Patent application EP 1 788 153 A2, for example, describes a
web transfer box with a transfer zone that is divided into 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. Here, the pick-up zone is sealed off
towards the atmosphere and the stabilizing zone by means of seals.
The two vacua in the pick-up zone and the stabilizing zone can be
set and adjusted separately in this process, with the vacuum in the
pick-up zone generally being higher than in the stabilizing zone in
practice.
[0005] Ever increasing machine speeds require higher and higher
vacua in the transfer zone, particularly in the pick-up zone,
however conventional seals cannot always guarantee adequate
sealing. Particularly in transfer devices with a high vacuum,
conventional seals are not sufficient to perform this function
satisfactorily.
SUMMARY
[0006] The problem thus addressed by the present invention is to
create a web transfer device and a transfer process that provides
good sealing of the vacuum in the transfer zone, even at high
machine speeds.
[0007] This problem is solved by a device in which the transfer
zone is limited or divided by the sealing mechanism and where
suction can be applied through an opening to a space between the
sealing lips of the sealing mechanism.
[0008] By applying suction to the sealing mechanism, a higher
vacuum can be set in the transfer zone and, due to the reduced
leakage of air through the sealing mechanism and into the transfer
zone, a lower performance suction unit can be used, which results
in energy savings.
[0009] Applying suction between the individual sealing lips also
leads to improved closure of the seal on the material web to be
transferred or on a supporting belt because the individual sealing
lips adhere to the web by suction.
[0010] In a preferred embodiment the material web is supported in
the transfer zone on a supporting belt, which should preferably be
air-permeable. The supporting belt provides additional purchase for
the material web.
[0011] It is an advantage if the sealing lips of the sealing
mechanism form a labyrinth seal. If the individual sealing lips are
mounted in a labyrinth arrangement, the sealing effect can be
improved substantially.
[0012] In a favourable embodiment the transferzone comprises a
pick-up zone and a subsequent stabilizing zone. The vacua in these
two zones can then be selected such that the material web is lifted
off the first supporting surface as close as possible to the
tangent point and such as to provide optimum guiding and
stabilizing of the web in the stabilizing zone.
[0013] Here it is useful if the sealing mechanism to which suction
can be applied forms the limit of the pick-up zone, in which case
it can also be located between the pick-up zone and the stabilizing
zone. During operation, the pick-up zone is normally placed under a
higher vacuum than the stabilizing zone, which is why it is
particularly desirable to have a good seal in the pick-up zone.
[0014] It is an advantage if the sealing mechanism is
swivel-mounted. With a swivel-mounted sealing mechanism, it is easy
to perform maintenance work or change a supporting belt.
[0015] The invention also relates to a corresponding process for
transfer of a material web, where suction is applied to a sealing
mechanism in the transfer zone.
[0016] By applying suction to the sealing mechanism, a certain
level of vacuum can be maintained in the transfer zone throughout
the entire production process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] 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:
[0018] FIG. 1 is a schematic side view of a web transfer device
according to the invention;
[0019] FIG. 2 is an enlarged section of the schematic side view in
FIG. 1;
[0020] FIG. 3 is a side view of a further web transfer device
according to the invention; and
[0021] FIG. 4 is a schematic detail of the web transfer device
according to the invention with swivel-mounted sealing
mechanisms.
DETAILED DESCRIPTION
[0022] The web transfer device 5 according to the invention is
shown in FIG. 1. 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. In the present example, this first
supporting surface 3 is a rotating and heated drying cylinder. Then
the material web 1 and the supporting belt 2 are lifted off the
first supporting surface 3 by the web transfer device 5 and
transferred to the subsequent supporting surface 4. For this
purpose, a vacuum is applied to the web transfer device 5, causing
the material web 1 and the supporting belt 2 to be lifted off the
first supporting surface 3 by suction and stabilized until they are
transferred to the subsequent supporting surface 4. On one side the
transfer zone 6 is sealed over the entire machine width by means of
the sealing mechanism 10, to which suction is applied. In the
present example, the subsequent supporting surface 4 is a rotating
suction roll around which the material web 1 and the supporting
belt 2 are guided with the aid of vacuum. After the suction roll
the material web 1 and the supporting belt 2 are transferred to a
further drying cylinder. The direction of rotation of the two
drying cylinders and of the suction roll is indicated by
arrows.
[0023] FIG. 2 shows a detailed view of the sealing mechanism 10 to
which suction is applied, as illustrated in FIG. 1, where the
reference numerals used in all figures refer to the same items. The
sealing mechanism 10 consists of several sealing lips 11. These can
have a blade-like shape and can form a labyrinth seal. The sealing
lips can be made of silicone, Teflon, or another synthetic
material.
[0024] A space 12 is formed between the sealing lips 11. According
to the invention, the air in this space 12 is extracted by suction
through the opening 7 in the sealing lip mounting. The direction of
flow 13 of the air extracted is indicated here by arrows. The
vacuum prevailing between the sealing lips 11 ensures that the
sealing lips 12 close evenly on the supporting belt 2 because the
sealing mechanism 10 adheres to the supporting belt by suction.
Leakage air flowing in is also removed through the opening 7 by
suction. In the transfer zone 6 there is also a vacuum, and the
vacuum flow direction is indicated by the two arrows 8. The vacuum
inside the sealing mechanism 10 and the vacuum in the transfer zone
6 can be generated by the same vacuum blower. It would also be
possible, however, to generate the two vacua using separate
systems. It is also conceivable that the vacuum in the space 12 is
adjustable and regulated separately and independently of the vacuum
in the transfer zone 6. The sealing mechanism 10 can also have
several openings 7, located at regular intervals across the machine
running direction, for example. The opening 7 can also be connected
directly to the transfer zone 6, where the leakage air in the space
12 is sucked through the opening 7 into the transfer zone 6. A
reducing damper can also be installed in the connecting duct
between the opening 7 and the transfer zone 6 in order to set a
lower vacuum in the space 12 than in the transfer zone 6.
[0025] FIG. 3 shows a further variant of the invention. Here, the
web transfer device 5 has two sealing mechanisms 10 and 10'. In
this case, the transfer zone 6 is divided into a pick-up zone 6'
and a stabilizing zone 6''. These two zones (6', 6'') are separated
by the sealing mechanism 10'. As an option, a further seal 14 may
also be provided, in which case there is an additional zone between
the sealing mechanism 10' and the seal 14 that may have a different
pressure to the pick-up zone 6' and the stabilizing zone 6''. It is
also conceivable that the pressure in this further zone can be set,
by means of a gate damper for example. In the pick-up zone 6', the
material web 1 and the supporting belt 2 are lifted off the first
supporting surface 3 by vacuum. In the stabilizing zone 6'', the
material web 1 and the supporting belt 2 are stabilized with the
aid of vacuum. The vacuum in the pick-up zone 6' is preferably
higher than the vacuum in the stabilizing zone 6''. Preferably, it
should be possible to set and adjust the pressure ratios in the
pick-up zone 6' and the stabilizing zone 6'' separately. Both
sealing mechanisms 10 and 10' are subject to suction in FIG. 3,
however it is conceivable that suction is applied to only one of
the two suction mechanisms 10, 10'. It is also conceivable that
suction is applied to the seal 14.
[0026] FIG. 4 shows the sealing mechanisms 10 and 10' from FIG. 3
in detail. It clearly shows that suction can be applied to the
space 12 between the sealing lips 11 through the opening 7. Here,
the sealing mechanism 10' is connected to a vacuum system via the
flow duct 9. The two sealing mechanisms 10 and 10' can be connected
to the vacuum system for the pick-up zone, but it is also possible
that both or one sealing mechanism 10 and/or 10' is connected to a
separate vacuum system or to the vacuum system for the stabilizing
zone 6''. The vacuum in the stabilizing zone 6'' can also be
generated via the vacuum system for the suction roll.
[0027] The sealing mechanisms 10 and 10' can be swivelled round an
articulated joint 15 and 15'. The dot-dash lines here show the
sealing mechanisms 10 and 10' swung into position outwards. This
swing movement of the sealing mechanism 10, 10' facilitates
maintenance work and changing of the supporting belt 2. It is also
possible to swing the sealing mechanisms into position downwards
(not shown). As a result, the sealing mechanism 10, 10' can yield
if the paper wraps right round the cylinder or round the first
supporting surface 3, and can thus prevent damage to the sealing
lips 11 and the supporting belt 2. The sealing mechanism 10, 10'
can also be pre-stressed by means of a spring and motor, or by a
pneumatic cylinder, which swing it back into the sealing position
if it is moved. If a motor or a pneumatic cylinder is used, the
sealing mechanism 10, 10' can also be swung out of position for
maintenance work.
[0028] 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 sealing mechanism 10, 10'
limits the stabilizing zone 6''. It is also conceivable that the
web transfer device 5 is used to transfer a material web 1 at a
converting or winding unit of a paper machine.
[0029] The web transfer device 5 according to the invention can be
used in all processes in which a material web 1 is transferred with
the aid of vacuum from a first supporting surface 3, which can also
be a plane, to a subsequent supporting surface 4, to which suction
need not be applied.
[0030] 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.
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