Note: Descriptions are shown in the official language in which they were submitted.
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Air guide plate for leading away an edge strip of a
material web, method for leading away an edge strip of
the material web, and use of the air guide plate and of
the method
BACKGROUND OF THE INVENTION
The present invention relates to an air guide plate for
discharging an edge strip of a running, planar material
web, to a method for discharging an edge strip of the
material web, and to the use of the air guide plate and
of the method to discharge an edge strip.
PRIOR ART
In the production of planar material webs, an edge
strip is usually detached from both sides of the
material web. This detachment takes place for example
in order to obtain an exact width of the material web,
in order to produce precisely defined edges of the
material web, in order to achieve uniform properties
and conditions across the width of the material web or
of the transverse profile, and in order to ensure a
smooth machine run for production reasons. In order
that the edge strips detached from the running, planar
material web do not run along with the finished
material web and possibly become wound up with the
finished product produced, the edge strips are usually
knocked off and continuously discharged. In order to
sever edge strips, nozzle(s) subjected to compressed
air, known as knock-down nozzle(s), are used as knock-
off devices in the prior art. The discharged edge
strips are recycled, where possible, as a valuable
resource and fed back to the production process.
Discharging devices for discharging edge strips of a
running, planar material web, in particular made of
tissue, paper, paperboard, board, film or textile, are
known in the prior art. Known discharging devices are
for example (discharging) hoppers with or without a
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guide plate. Moreover, vacuum devices and compressed
air devices, in particular blowing nozzles and fans,
are additionally also used to guide the edge strip.
WO 2013/127008 describes a method and a device for
handling edge strips of a paper web. An edge strip
detached from the rest of the paper web is guided into
a discharging device by an air nozzle, wherein the edge
strip is optionally knocked off by the air nozzle, in
particular severed, and discharged further into a
pulping device, in particular a pulper. For example,
vacuum systems, transport fan systems and injector
systems are cited as edge-strip conveying systems.
13 Known air guide plates and methods for discharging an
edge strip of a running, planar material web are still
worthy of improvement and often have the drawback that,
during discharging, only insufficient separation
between the detached edge strip and the material web
occurs, such that the edge strip is arranged on the
material web again and is entrained by the material
web. Furthermore, the air guide plates and methods for
discharging an edge strip that are known from the prior
art do not sufficiently and reliably stabilize the edge
strip in order to ensure good guidance of the edge
strip. Moreover, the known air guide plates and methods
for discharging are not adjustable easily, quickly and
reproducibly to different edge-strip widths, production
speeds of the material webs and weights per unit area
of the edge strip. Furthermore, in the known
discharging devices and methods, energy, in particular
energy of compressed air systems that are not required,
is wasted on account of a lack of and/or imprecise
adjustment capabilities.
Therefore, the present invention is based on the object
of providing an improved air guide plate and an
improved method for discharging a running, planar
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material web, in particular made of tissue, paper,
paperboard, board, film or textile, in which the
abovementioned drawbacks are avoided. In particular, the
air guide plate and the method for discharging a material
web are intended to allow reliable and reproducible
discharging of an edge strip at all weights per unit area
and production speeds of the material web and to prevent
retroactive arrangement of the edge strip with respect
to the material web. Furthermore, the air guide strip is
intended to be adjustable easily, quickly and
reproducibly. In particular, losses of production or
fluctuations in quality of the material web produced,
which can be ascribed to the air guide plate and the
method, are intended to be largely avoided.
SUMMARY OF THE INVENTION
Surprisingly, it has now been found that the object is
achieved by an air guide plate and method as described
below.
Compared with known air guide plates, the air guide plate
according to the invention for discharging an edge strip
of a running, planar material web, in particular made of
tissue, paper, paperboard, board, film or textile, has
at least one air intake gap between the one or more blow-
out nozzle(s) and the at least one edge-strip outlet
plaPe.
Therefore, the subject of the invention is an air guide
plate for discharging an edge strip of a running, planar
material web, in particular made of tissue, paper,
paperboard, board, film or textile having an edge-strip
surface that has an edge-strip length in the machine
direction and an edge-strip width in the cross-machine
direction, an edge-strip outer edge which terminates a
lateral edge of the running, planar
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material web toward the outside in the cross-machine
direction, and an edge-strip inner edge which is
arranged in the direction of the middle of the running,
planar material web, comprising, arranged in the
direction of an axis of longitudinal extent, at least
one edge-strip inlet plate, one or more blow-out
nozzle(s) and at least one edge-strip outlet plate,
wherein the one or more blow-out nozzle(s) is/are
arranged between the at least one edge-strip inlet
plate and the at least one edge-strip outlet plate and
the air guide plate has an air-guide-plate outer edge
on the side away from the middle of the material web,
wherein at least one air intake gap is arranged between
the one or more blow-out nozzle(s) and the at least one
edge-strip outlet plate, wherein the at least one air
intake gap has a length in the range of 0.2 to 5 mm in
the direction of the axis of longitudinal extent.
A further subject of the invention is a method for
discharging an edge strip of a running, planar material
web, comprising the following steps of:
a) providing at least one edge strip of a running,
planar material web, in particular made of
tissue, paper, paperboard, board, film or
textile having an edge-strip surface that has
an edge-strip length in the machine direction
and an edge-strip width in the cross-machine
direction, an edge-strip outer edge which
terminates a lateral edge of the running,
planar material web toward the outside in the
cross-machine direction, and an edge-strip
inner edge which is arranged in the direction
of the middle of the running, planar material
web,
b) providing at least one air guide plate for
discharging the edge strip provided in step a),
comprising, arranged in the direction of an
axis of longitudinal extent, at least one edge-
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strip inlet plate, one or more blow-out
nozzle(s) and at least one edge-strip outlet
plate, wherein the one or more blow-out
nozzle(s) is/are arranged between the at least
one edge-strip inlet plate and the at least one
edge-strip outlet plate and the air guide plate
has an air-guide-plate outer edge on the side
away from the middle of the material web,
c) subjecting the one or more blow-out nozzle(s)
to a fluid flow, in particular a compressed air
flow,
d) discharging the edge strip provided in step a)
into at least one discharging device, in
particular a discharging hopper,
wherein the at least one blow-out nozzle or plurality
of blow-out nozzles subjected to the fluid flow emit(s)
in the direction of the air-guide-plate outer edge.
A further subject of the invention is the use of the
air guide plate in a machine for producing planar
material webs, in particular selected from a tissue
machine, a paper machine, a board machine, a bogus
paper machine, a coater, a laminator, a coating
machine, a film machine, a textile machine, a sliver
machine and combinations thereof.
A further subject of the invention is the use of the
method for discharging an edge strip of a running,
planar material web in the production of a planar
material web, in particular selected from the
production of paper, paperboard, corrugated board,
board, graphic papers, packaging papers, hygienic
papers, in particular tissue, laminated paper, films,
textile webs, fibrous webs and combinations thereof.
DETAILED DESCRIPTION OF THE INVENTION
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In the context of the present invention, running is
understood as meaning forward movement at the
production speed, in particular of a produced web made
of tissue, paper, paperboard, board, laminated paper,
films and combinations thereof.
In the context of the present invention, planar is
understood as meaning a flat surface which has a
minimum thickness with respect to its length in the
machine direction and to its width in the cross-machine
direction, in each case with respect to the production
machine. For example, the thicknesses determined to
EN ISO 12625-3:2014 are in the range of 50 pm to
1000 pm.
In the context of the present invention, a material web
is understood to be a planar web produced on a web
production machine. In particular, a material web is
understood to be a produced planar web made of tissue,
paper, paperboard, board, laminated paper, films and
combinations thereof.
In the context of the present invention, an air intake
gap is understood to be an opening through which
ambient air can pass, in particular be drawn in. An air
intake gap can in particular be selected from a slot, a
hole, a nozzle and combinations thereof.
In a preferred embodiment of the air guide plate
according to the invention, the at least one blow-out
nozzle is arranged at an enclosed angle, or the
plurality of blow-out nozzles are arranged at one or
more enclosed angles, in the range of 00 to 45 ,
preferably in the range of 5 to 20 , to the air-guide-
plate outer edge, and face in the direction of the air-
guide-plate outer edge.
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In a preferred embodiment of the air guide plate
according to the invention, one or more blow-out
nozzle(s) that is/are subjected to a fluid flow, in
particular a compressed-air flow, is/are arranged in
the region of the edge strip across the edge-strip
width or less than the edge-strip width.
In a preferred embodiment of the air guide plate
according to the invention, an axis of rotation, about
which the air guide plate is arranged so as to be
pivotable, is arranged in the cross-machine direction
in the region of the edge-strip inlet plate.
In a preferred embodiment of the air guide plate
according to the invention, the air guide plate is
arranged so as to be pivotable about the axis of
rotation in the cross-machine direction such that an
edge strip entering the air guide plate is deflected by
an angle in the range of n to 2n, preferably in the
range of n to 3/2n, with respect to the entering edge
strip.
In a preferred embodiment of the air guide plate
according to the invention, at least one knife element
is arranged, in the case of the pivotable air guide
plate, at the edge-strip outlet side of the at least
one edge-strip outlet plate, said knife element
forming, with a counterpart knife arranged opposite, a
shearing gap when the guide plate is pivoted. In
particular, a knife element is selected from an edge, a
tip, a blade, a cutting edge, a prong, a perforation, a
corrugation and combinations thereof.
In the context of the present invention, a counterpart
knife is understood to be a knife which is arranged
such that one or more counterpart knives form, with one
or the plurality of knife element(s), a shearing device
for severing the edge strip of the material web. In
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particular, a counterpart knife is selected from an
edge, a tip, a blade, a cutting edge, a prong, a
perforation, a corrugation and combinations thereof.
In the context of the present invention, severing is
understood as meaning the dividing from a web of an
edge strip in the direction of the edge-strip width in
the cross-machine direction.
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the at least one blow-out
nozzle that is subjected to the fluid flow emits at an
enclosed angle, or the plurality of blow-out nozzles
that are subjected to the fluid flow emit at one or
more enclosed angle(s), in the range of 0 to 45 ,
preferably in the range of 5 to 20 , to the air-guide-
plate outer edge.
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the one or more blow-out
nozzle(s) is/are subjected to the fluid flow in the
region of the edge strip across the edge-strip width or
less than the edge-strip width.
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the discharging, in step
d), of the edge strip, provided in step a), into at
least one discharging device is initiated with a
pivoting movement of the at least one air guide plate
provided in step b).
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the pivoting movement of
the at least one air guide plate provided in step b) is
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carried out by a pivoting device selected from an
electric pivoting device, a pneumatic pivoting device,
a hydraulic pivoting device and combinations thereof.
In the context of the present invention, an electric
pivoting device is understood to be an electrically
operated pivoting device.
In the context of the present invention, a pneumatic
pivoting device is understood to be a pneumatically
operated pivoting device.
In the context of the present invention, a hydraulic
pivoting device is understood to be a hydraulically
operated pivoting device.
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the pivoting movement of
the at least one air guide plate provided in step b) is
carried out at an angle in the range of n to 2n,
preferably in the range of n to 3/2n, with respect to
the entering edge strip.
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the edge strip is
severed, during the pivoting movement, by shear stress
between at least one knife element arranged on the at
least one edge-strip outlet plate and a counterpart
knife arranged opposite.
In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, in a further step e), the
edge strip discharged into at least one discharging
device in step d) is introduced into at least one
pulping device, in particular a pulper.
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In a preferred embodiment of the method according to
the invention for discharging an edge strip of a
running, planar material web, the introduction of the
severed edge strip is carried out in combination with a
knock-off device.
DESCRIPTION OF THE FIGURES AND EXAMPLES
The invention will now be explained in the following
text by way of figures 1 to 3 and exemplary embodiment
1.
Figure 1 schematically shows a cross section through
the air guide plate according to one
embodiment of the invention,
Figure 2 schematically shows a detail of a view of the
air guide plate according to one embodiment
of the invention with a material web arranged
above the air guide plate,
Figure 3 schematically shows a cross section through a
pivotable air guide plate according to an
embodiment of the invention according to
figure 1, with different angular positions of
the air guide plate.
Figure 1 illustrates an embodiment of an air guide
plate 1 according to the invention schematically as a
cross section in the machine direction MD. The air
guide plate 1 comprises an edge-strip inlet plate 6,
one or more blow-out nozzle(s) 71, 72, 73, 74, 75, an
air intake gap 10 and an edge-strip outlet plate 8. The
edge-strip inlet plate 6, the one or more blow-out
nozzle(s) 71, 72, 73, 74, 75, the air intake gap 10 and
the edge-strip outlet plate 8 are arranged along an
axis of longitudinal extent L. The cross profile of the
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air guide plate 1 can resemble an airfoil cross
profile. An entering edge strip 2 is guided over the
edge-strip inlet plate 6, caught by a fluid flow S
which flows out of the one or more blow-out nozzle(s)
71, 72, 73, 74, 73, guided past the air intake gap 10
and guided in the direction of the edge-strip outlet
plate 8. The air guide plate 1 has an axis of rotation
D, about which it is pivotable. In the illustrated
position, the air guide plate 1 has been pivoted into a
discharging device 13. A pivoting radius of the air
guide plate 1 is depicted as a dashed line. The edge
strip 2 is guided in a direction of forward movement V
into the discharging device 13 by the air guide plate
1. On the pivoting-in side for the air guide plate 1, a
counterpart knife 12 is arranged on the discharging
device 13. When the air guide plate 1 is pivoted in,
when the knife element 11 and the counterpart knife 12
are located opposite one another, a shearing gap is
formed, in which the edge strip 2 is severed. The edge
strip 2 is guided out of the discharging device 13 into
a pulping device 14.
Figure 2 schematically illustrates a detail of a view
of the air guide plate 1 according to one embodiment of
the invention with a material web 3 arranged above the
air guide plate 1. The edge strip 2 has been detached
from the material web 3. The edge strip 2 has an edge-
strip width B in the cross-machine direction CD, an
edge-strip outer edge 4, an edge-strip inner edge 5,
and is guided in the direction of forward movement V.
The edge-strip outer edge 4 terminates, in the cross-
machine direction CD, a lateral edge of the running,
planar material web 3 toward the outside. The edge-
strip inner edge 5 is arranged in the direction of the
middle of the running, planar material web 3. The edge
strip 2 is arranged such that it runs in via the edge-
strip inlet plate 6 of the air guide plate 1, via the
blow-out nozzle(s) 71, 72, 73, 74, 75, the air intake
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gap 10 and the edge-strip outlet plate 8. The edge-
strip inlet plate 6, the blow-out nozzle(s) 71, 72, 73,
74, 75, the air intake gap 10 and the edge-strip outlet
plate 8 are arranged along the axis of longitudinal
extent L. The air guide plate 1 has an air-guide-plate
outer edge 9, which is arranged on the side away from
the middle of the material web 3. The blow-out
nozzle(s) 71, 72, 73, 74, 75 face in the direction of
the air-guide-plate outer edge 9 and are arranged at an
enclosed angle a which is formed between the at least
one of the respective blow-out nozzle(s) 71, 72, 73,
74, 75 and the air-guide-plate outer edge 9.
Figure 3 schematically illustrates a cross section
through the air guide plate 1 in the machine direction
MD according to an embodiment of the invention
according to figure 1, with differently arranged
angular positions of the air guide plate 1. The edge-
strip inlet plate 6, the blow-out nozzle(s) 71, 72, 73,
74, 75, the air intake gap 10 and the edge-strip outlet
plate 8 are arranged along the axis of longitudinal
extent L. The air guide plate 1 is arranged so as to be
pivotable about the axis of rotation D and can be
pivoted for example from a position of the air guide
plate 1 that is illustrated by dashed lines into a
position of the air guide plate 1 that is illustrated
by solid lines. The direction of the axis of
longitudinal extent L is different in the position
illustrated by dashed lines than the position of the
air guide plate 1 that is illustrated by solid lines.
The knife element 11 is illustrated as an optional
embodiment. When the air guide plate 1 is pivoted out
of the position illustrated by dashed lines into the
position illustrated by solid lines, the edge strip 2
is guided over the counterpart knife 12 by the air
guide plate 1, wherein the edge strip 2 is severed. The
edge strip 2 is discharged into the discharging device
in the direction of forward movement V in the position
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of the air guide plate 1 that is illustrated by solid
lines.
List of reference signs
1: Air guide plate
2: Edge strip
3: Material web(s)
4: Edge-strip outer edge
5: Edge-strip inner edge
6: Edge-strip inlet plate
71, 72, 73, 74, 75: Blow-out nozzle(s)
8: Edge-strip outlet plate
9: Air-guide-plate outer edge
10: Air intake gap
11: Knife element
12: Counterpart knife
13: Discharging device
14: Pulping device
B: Edge-strip width
D: Axis of rotation
CD: Cross-machine direction
MD: Machine direction
L: Axis of longitudinal extent
S: Fluid flow
V: Direction of forward movement of
the planar material web
a: Enclosed angle
Example 1
The air guide plate according to the invention was
tested as a fixed air guide plate and as a pivotable
air guide plate. The air guide plate was mounted under
the material web, in particular a paper web. The air
guide plate had between one and ten blow-out nozzles
and the air intake gap between the blow-out nozzles and
the edge-strip outlet plate had a length in the range
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of 0.2 to 5 mm in the direction of the axis of
longitudinal extent. The blow-out nozzles were oriented
in the direction of the air-guide-plate outer edge and
arranged at an enclosed angle of 0 to 45 , preferably
5 to 20 , to the air-guide-plate outer edge.
The edge strip was introduced into a discharging hopper
or a discharging channel by the air guide plate. In
part tests, nozzles, for example those known as Vita
nozzles, were arranged in the discharging channel. In
combination with the air guide plate according to the
invention, in order to knock off the edge strip,
pressurized knock-down nozzles were also tested as a
separating device for the edge strip. In a further
preferred embodiment, the surfaces of the air guide
plate according to the invention were provided with a
nonstick coating, in particular a TerraDry GT3/CT3 from
the company Voith Paper Onsite Services, Workshop,
Parhalahti, Finland. In a further preferred embodiment,
the nonstick coating was made of
polytetrafluoroethylene, in particular Teflon. In a
further preferred embodiment, the air guide plate
according to the invention was produced from plastic,
for example UHMWPE, with or without the addition of
glass beads.
