Note: Descriptions are shown in the official language in which they were submitted.
CA 02201668 2002-09-23
ROLL PRESS
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a roll press of a
machine, e.g., a paper making machine, including a
suction press roll that lifts a material web, e.g.,
cardboard or paper, from a screen or similar surface
having an associated press felt guided around the suction
press roll, and having a pay-out press roll that takes
the material web from the suction press roll and forms a
press gap with the suction press roll. The pay-out press
roll pays out the material web to a subsequent part of
the machine.
2. Discussion of the Background Information
A roll press similar to the one generally described
above is used in particular for dewatering a material web
being processed. The dewatering capacity achieved by
such a roll press is, among other things, dependent on
the number of press gaps. However, there are practical
limits to increasing the number of press gaps associated
with the roll press. For this reason, the prior art has
been proposed positioning at least one other separate
pair of rolls after the pair of rolls formed by the
suction press roll and the pay-out press roll to form an
additional roll gap. Practical considerations, such as
space required for house this arrangement, are
considerable. The open tensions
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produced between the respective pairs of rolls are also
problematic.
SUMMARY OF THE INVENTION
The present invention is directed towards the
provision of a roll press, as described above, which
ensures greater pressing capacity, i.e. a higher
dewatering capacity, with a minimal space requirement
than the roll presses of the prior art.
In accordance with an aspect of the present
invention, there is provided a roll press of a machine
for producing a material web comprising:
a suction press roll;
a press felt associated with, and guided around at
least a portion of the suction roll;
the suction roll lifting the material web from a
screen;
a pay-out press roll forming a press gap with the
suction press roll to transfer the material web to the
pay-out roll;
a first additional press roll forming a first
additional press gap with the suction press roll;
a first addition press felt, associated with the
first additional press roll, passing through the first
additional press gap;
a second additional press roll forming a second
additional press gap with the pay-out press roll;
a second additional press felt, associated with the
second additional press roll, passing through the second
additional press gap;
at least one of the press gap, the first additional
press gap, and the second additional press gap comprising
an elongated press gap that is elongated in a travel
direction of the material web.
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In accordance with another aspect of the present
invention, there is provided a roll press for a
continuous material web producing machine comprising:
a first press roll;
a second press roll;
a third press roll;
a fourth press roll;
said first, second, third, and fourth press rolls
arranged to form a first, second, and third press gap;
said first press roll positioned to lift the
material web off a screen;
said second press roll positioned adjacent said
first press roll to form said second press gap and to
transfer the material web to said second press roll;
said second press rolls forming a part of each of
said second and third press gaps;
said first press gap comprising a two-sided
dewatering gap; and
said second and third press gaps comprising one-
sided dewatering gaps
According to the invention, therefore, each of the
suction press roll and the pay-out press roll is
associated with at least one additional press roll to
form respective additional press gaps. A press felt may
be guided by each additional press roll, and at least one
of the respective additional press gaps formed may be
elongated in the travel direction of the material web.
The preferred embodiment of the present invention
produces an extremely compact roll press with a high
pressing capacity. In simplest embodiment of the present
invention, a roll apparatus may be produced including
three press gaps and four rolls. This embodiment may
perform dewatering on both sides of the web in the region
of the first press gap, e.g., between the suction press
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roll and the associated additional press roll; on at
least one side of the web in the region of a second press
gap, e.g., between the suction press roll and the pay-out
press roll; and on at least one side of the web in the
region of a third press gap, e.g., between the pay-out
press roll and the associated additional press roll.
Further, from a takeover point on a screen end to a pay-
out point, a closed
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web guidance may be produced which has preliminary
dewatering of the cardboard or paper web. Because
rewetting may be kept to a minimum, a maximal dry content
can be achieved. Because there are no open tensions
between the rolls, stretching of the paper may be
substantially eliminated. Further, in accordance with the
present invention, no losses in wet strength may occur.
According to the present invention, the first open tension
may occur only in connection with the press device when the
web has attained a substantially maximal wet strength.
Thus, a crucial advantage of the present invention over the
prior art is that, due to the at least one elongated
additional press gap, a considerably higher pressing
capacity or dewatering capacity may be achieved despite the
extremely compact nature of the roll apparatus.
In this connection, it may be particularly
advantageous to arrange at least the additional press gap
formed between the pay-out press roll and the associated
additional press roll as an elongated press gap.
In an alternative embodiment of the roll press
according to the present invention, the suction press roll
may rest against or abut the screen through the associated
press felt to lift off the material web. As a result, the
lift off of the material web from the screen may be
appreciably simplified to the simplest of designs.
Advantageously, at least one of the additional press
rolls may be a deflection compensation roll having a
rotating roll jacket, a core passing through the roll
jacket, and at least one hydrostatic and/or hydrodynamic
support element supporting the roll jacket on the core.
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In a preferred embodiment, the suction press roll, the
pay-out press roll, and the additional press rolls may be
positioned and/or supported to cancel out the forces of the
press gaps, and, thus, need not be absorbed by the machine
foundation and/or an external seating. Thus, the external
seating may be optionally included.
A preferred embodiment of the present invention
provides that the pay-out press roll may be associated with
at least one additional press roll that may include a
deflection compensation roll having a flexible roll jacket,
a core passing through the flexible roll jacket, and at
least one non-convex hydrostatic and/or hydrodynamic
support element. The deflection compensation roll and the
pay-out press roll may form an elongated press gap
elongated in the travel direction of the material web.
Due to the elongated press gap formed between the pay-
out press roll and the associated additional press roll,
optimum dewatering capacity is achieved while maintaining
a compact roll apparatus comprised of a small number of
rolls.
Preferably, the suction press roll may be associated
with at least one additional press roll that includes a
deflection compensation roll having a flexible roll jacket,
a core passing through the flexible roll jacket, and at
least one non-convex hydrostatic and/or hydrodynamic
support element. The deflection compensation roll and the
suction press roll forming an elongated press gap elongated
in the travel direction of the material web. The elongated
press gap further optimizing the dewatering capacity.
The pay-out press roll may advantageously be formed by
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a deflection compensation roll having a rotating roll
jacket, a core passing through the roll jacket, and at
least one hydrostatic and/or hydrodynamic support element
supporting the roll jacket on the core. Preferably, a
deflection compensation roll type pay-out press roll has a
rigid roll jacket. However, such a pay-out press roll may
alternatively include a flexible jacket.
The roll jacket of a deflection compensation roll type
pay-out press roll may be radially fixed on its ends, at
least during operation. Accordingly, radial movements of
the pay-out press roll during operation may be
substantially prevented, which, consequently, maintains the
respective positioning of the rolls even when the press is
loaded.
The deflection compensation roll type pay-out press
roll may alternatively be associated with at least one
additional press roll that likewise includes a deflection
compensation roll. According to this embodiment, the
hydraulically actuated hydrostatic and/or hydrodynamic
support elements of each of the additional press roll and
the pay-out press roll may be hydraulically coupled to each
other. This embodiment may be advantageous, for example,
in connection with a position regulation.
To achieve the most defined conditions possible, the
pay-out press roll may be fixed to a stanchion or upright
support beam in a predetermined position, e.g., without the
possibility of a radial deflection. The stanchion may be
mounted to the machine foundation in a stationary fashion.
The pay-out press roll may include a deflection
compensation roll having a flexible roll jacket, a core
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passing through the flexible roll jacket, and at least one
non-convex hydrostatic and/or hydrodynamic support element.
The deflection compensation roll and at least one of the
associated additional press roll and suction press roll may
form an elongated press gap elongated in the travel
direction of the material web.
Furthermore, if the additional press roll, associated
with the deflection compensation roll type pay-out press
roll, includes a deflection compensation roll having a
flexible roll jacket, then the support elements of each of
the pay-out press roll and the associated press roll may be
at least substantially smooth on their sides oriented
toward their respective roll jacket to form a press gap
that is at least substantially smooth.
In accordance with the present invention, at least one
of the rolls may include a deflection compensation roll
having a roll jacket that may be movable in the radial
direction. In this instance, the roll jacket is preferably
rigid, although, the present invention also contemplates
utilizing a flexible roll jacket in an alternative
embodiment.
Accordingly, to produce the most defined conditions
possible during operation, at least the press gap formed
between the pay-out press roll and the associated
additional press roll may be suitably fixed in a
predetermined position by a corresponding position
regulation.
The suction press roll may be a hollow roll having a
roll jacket supported on its interior and rotatable around
a core. In this instance, the suction press roll may
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preferably be provided with an external suction box that
suctions off a region disposed inside the roll.
The present invention may be directed to a roll press
of a machine for producing a material web. The roll press
may include a suction press roll; a press felt associated
with, and guided around, at least a portion of the suction
roll; the suction roll lifting the material web from a
screen; and a pay-out press roll forming a press gap with
the suction press roll to transfer the material web to the
pay-out roll. The roll press may also include a first
additional press roll forming a first additional press gap
with the suction press roll; a first additional press felt,
associated with the first additional press roll, passing
through the first additional press gap; a second additional
press roll forming a second additional press gap with the
pay-out press roll; a second additional press felt,
associated with the second additional press roll, passing
through the second additional press gap; and at least one
of the press gap, the first additional press gap, and the
second additional press gap comprising an elongated press
gap that is elongated in a travel direction of the material
web.
In accordance with another feature of the present
invention, the roll press may also include a felt changing
retraction device for changing at least one of the press
felt, and the first and second additional press felts.
In accordance with still another feature of the
present invention, the roll press may also include a
cantilever carrier carrying the press felt in a
cantilevered manner to facilitate replacing the press felt.
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In accordance with a further feature of the present
invention, the roll press may also include a support device
for adjustably positioning the second additional press roll
for facilitating changing the second additional press felt
for the second additional press roll. The support device
may include a coupling device to couple a core of the
second additional press roll to the support device.
In accordance with a still further feature of the
present invention, the roll press may also include a
support device for adjustably positioning the suction press
roll for facilitating changing the first additional press
felt. The support device may include a coupling device to
couple a core of the second additional press roll to the
support device, the core comprising a slip-mounted pipe.
The present invention may also be directed to a roll
press for a continuous material web producing machine. The
roll press may include a first press roll, a second press
roll, a third press roll, and a fourth press roll. The
first, second, third, and fourth press rolls may be
arranged to form a first, second, and third press gap. The
first press roll may be positioned to lift the material web
off a screen, the second press roll may be positioned
adjacent the first press roll to form the second press gap
and to transfer the material web to the second press roll,
and the second press roll forming a part of each of the
second and third press gaps. The first press gap may
include a two-sided dewatering gap and
the second and third press gaps may each include one-sided
dewatering gaps.
In accordance with another feature of the present
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invention, at least one of the second, third and fourth
press rolls may include a deflection compensation roll
having a rotatable jacket and support elements supporting
the rotatable jacket and forming a part of at least one of
the first, second, and third press gaps.
In accordance with another feature of the present
invention, each of the second, third and fourth press rolls
may include a deflection compensation roll having a
rotatable jacket and support elements supporting the
rotatable jacket and forming a respective part of the
first, second, and third press gap.
In accordance with a further feature of the present
invention, the support elements may include non-convex
support surfaces.
In accordance with a still further feature of the
present invention, the second and third press rolls may
include support elements having complementary support
surfaces for forming the third press gap. The third press
gap may include an elongated press gap elongated in a
travel direction of the material web.
In accordance with still another feature of the
present invention, the second press roll may include
support elements having a support surface complementary to
an outer circumference of the first press roll for forming
the second press gap. The second press gap may include an
elongated press gap elongated in a travel direction of the
material web.
In accordance with a still further feature of the
present invention, the fourth press roll may include
support elements having a support surface complementary to
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an outer circumference of the first press roll for forming
the first press gap. The first press gap may include an
elongated press gap elongated in a travel direction of the
material web.
In accordance with another feature of the present
invention, each of the first, second, third, and fourth
press rolls may include a respective first, second, third,
and fourth longitudinal axis, and the first, second, and
third longitudinal axis may be collinearly arranged to form
a roll line at a predetermined angle from a vertical
reference. Further, the fourth press roll may be arranged
adjacent the first press roll such that a connecting line
connecting the first and fourth longitudinal axis is
substantially perpendicular to the roll line.
In accordance with still another feature of the
present invention, each of the first, second, third, and
fourth press rolls may include a respective first, second,
third, and fourth longitudinal axis. The first and second
press roll may be arranged such that a line connecting the
first and second longitudinal axes may be at a
predetermined angle from a vertical reference. The third
press roll may be positioned adjacent the second press roll
such that a line formed through the second and third
longitudinal axes may be substantially parallel to the
vertical reference. The fourth roll may be positioned
adjacent the first roll such that a line connecting the
first and fourth longitudinal axes may be substantially
perpendicular to the predetermined angle.
In accordance with yet another feature of the present
invention, the first roll may include a suction press roll.
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Other advantageous embodiments and features of the
present invention may be ascertained by reviewing the
following detailed description of the present invention and
the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is further described in the
detailed description which follows, in reference to the
noted drawings by way of non-limiting examples of preferred
embodiments of the present invention, and wherein:
Figure 1 illustrates a simplified schematic partial
view of a first embodiment of a roll press according to the
present invention;
Figure 2 illustrates a simplified schematic view of an
alternative embodiment of the roll press according to the
present invention;
Figure 3 illustrates a partial view of the roll press
depicted in Figure 2 with force lines being indicated in
the gap regions;
Figure 4 illustrates the roll press depicted in Figure
2 during a phase in which the press felt for the suction
press roll is,being changed;
Figure 5 illustrates the roll press depicted in Fig.
2 during a phase in which the press felt for the additional
press roll associated with the pay-out press roll is being
changed; and
Figure 6 illustrates the roll press depicted in Fig.
~2 during a phase in which the press felt for the additional
press roll associated with the suction press roll is being
changed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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The particulars shown herein are by way of example and
for purposes of illustrative discussion of the preferred
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 invention. In this regard,
no attempt is made to show structural details of the
invention in more detail than is necessary for the
fundamental understanding of the invention, the description
taken with the drawings making apparent to those skilled in
the art how the several forms of the invention may be
embodied in practice.
Figure 1 illustrates a simplified schematic
representation of a roll press of a machine, e.g., a paper
making machine. The roll press may include a suction press
roll 4 that takes or lifts off a material web A, e.g.,
cardboard or paper, from a screen 1 and transfers material
web A to an associated press felt 6. Press felt 6 may be
guided around suction press roll 4 to carry the material
web Around suction press roll 4 with the aid of vacuum 8.
The roll press may also include a pay-out press roll 7
arranged to form a press gap with adjacent suction press
roll 4 through which press felt 6 and material web A.
After passing through press gap B, material web A is
transferred to, or taken by, pay-out press roll 7 to pay
out material web A to a subsequent part of the machine.
As shown, e.g., in Figure 1, suction press roll 4 may
abut or rests against screen 1 through press felt 6. Thus,
material web A may be directly transferred to press felt 6
with the assistance of suction press roll 4 and vacuum 8.
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Both suction press roll 4 and pay-out press roll 7 may
be associated with an additional press roll, e.g.,
additional press rolls 14 and 24, respectively. Further,
each of the additional press rolls 14 and 24 may be
associated with a press felt 15 and 25, respectively.
Suction press roll 4 may be arranged adjacent additional
press roll 14 to form a press gap R, through which, press
felt 6 and press felt 15 may pass. Further, material web
A may also pass through press gap R sandwiched between
press felt 6 and press felt 15. Pay-out press roll 7 may
be arranged adjacent additional press roll 24 to form press
gap S, through which, press felt 25 may pass. Further,
material web A may also pass through press gap S sandwiched
between pay-out press roll 7 and press felt 25.
Screen 1 may be part of a screen section of the
machine which may further include screen rolls 2 and 3 for
guiding screen 1. As shown, suction press roll 4
preferably abuts screen 1, i.e., through press felt 6, in
a region formed between screen rolls 2 and 3.
Material web A, which may be lifted off screen 1 by
the press felt 6 and suction press roll 4, may be
successively guided through press gaps R, B and S. Because
material web A is sandwiched between press felts 6 and 15
within press gap R, two-sided dewatering of material web A
occurs in press gap R due to the respective pressing of the
press felts 6 and 15 by suction press roll 4 and additional
press roll 14. Because material web A is sandwiched
between press felt 6 and pay-out press roll 7 within press
gap B, only one-sided dewatering occurs in press gap B due
to a suction effect via vacuum 8 through suction press roll
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4. Because material web A is sandwiched between pay-out
press roll 7 and press felt 25 within press gap S, one-
sided dewatering occurs in press gap S due to press felt 25
associated with additional press roll 24.
In the first embodiment represented in Fig. 1, suction
press roll 4 may be comprised of a hollow roll having a
rigid roll jacket 30. Rigid roll jacket 30 may be
supported on its interior by, and rotatable around, a core
32.
Suction press roll 4 may be provided with an external
suction box 34 to suction off a region 36 located within
rigid roll jacket 30.
Each of press gaps R and S may be formed as elongated
press gaps elongated in travel direction of material web A.
Further, press gap B may also be formed as an elongated
press gap elongated in the travel direction of material web
A.
Additional press rolls 14 and 24 and pay-out press
roll 7 may be comprised of deflection compensation rolls
having a circumferential roll jacket 17, 26, and 38,
respectively, a core 16 extending longitudinally through
each of the circumferential roll jackets, and at least one
hydrostatic and/or hydrodynamic support element 18, 27, 27'
and 40, respectively, supporting the respective roll jacket
17, 26, and 38 on core 16 within each respective press gap
region. As shown in Figure 1, roll jacket 38 may include
support elements associated with more than one press gap.
For example, roll jacket 38 may be supported in the region
of press gap S with at least one hydrostatic and or
hydrodynamic support element 27' positioned adjacent to
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support element 27 of additional press roll 24, and in the
region of press gap B with at least one hydrostatic and/or
hydrodynamic support element 40 positioned adjacent to
suction press roll 4.
In the preferred embodiment of the present invention,
roll jackets 26 and 38 may be made of a flexible material.
Because adjacent support elements 27 and 27' are positioned
to support roll jackets 26 and 38, respectively, and to
form an elongated press gap, i.e., press gap S, the press
surfaces of support elements 27 and 27' should be
complementary. Thus, in a preferred embodiment of the
present invention, hydrostatic and/or hydrodynamic support
elements 27 and 27' may include substantially planar press
surfaces for forming the elongated press gap S. However,
it is also contemplated that support elements 27 and 27'
may be formed by complementary concave and convex press
surfaces to ensure formation of a press gap S that is
elongated in the travel direction of the material web A.
Hydrostatic and or hydrodynamic support elements 40,
also associated with pay-out press roll 7 to support roll
jacket 38 and form an elongated press gap, i.e., press gap
B, may include a press surface that is complementary to an
outer surface of suction press roll 4. Thus, in accordance
with the preferred embodiment of the present invention, the
press surface of support element 40 may be concave with a
curvature to complement the outer curvature of rigid roll
jacket 30. Thus, flexible roll jacket 38 may be pressed
against rigid roll jacket 30 to form press gap B, which is
elongated in the travel direction of the material web A.
Hydrostatic and/or hydrodynamic support elements 18,
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which support roll jacket 17 and form an elongated press
gap, i.e., press gap R, may include a press surface that is
complementary to an outer surface of suction press roll 4.
Thus, in accordance with the preferred embodiment of the
present invention, the press surface of support element 18
may be concave with a curvature to complement the outer
curvature of rigid roll jacket 30. Thus, flexible roll
jacket 17 may be pressed against rigid roll jacket 30 to
form press gap R, which is elongated in the travel
direction of the material web A. Further, press gap R may
extend over the larger portion of the outer circumference
of suction press roll 4 than press gap B. Thus, the
concave press surface of support element 18 may be longer
than the concave press surface of support element 40.
The roll jacket of additional press roll 24 may also
include recesses for receiving press water. The recesses
may be formed, e.g., as circumferential grooves and/or
blind bores.
Cores 16 may be substantially stationary, at least
during operation. Further, pay-out press roll 7 may be
provided with a roll jacket that may be radially fixed in
place at its ends, at least during operation.
As shown in Figure 1, axes of each of suction press
roll 4, pay-out press roll 7, and additional press roll 24
may be substantially collinearly arranged to form a line
positioned at a predetermined angle from a vertical
reference line, e.g., perpendicular to a base of the
machine. In accordance with the preferred embodiment, the
line formed by the collinear arrangement of the rolls may
be positioned, e.g., at approximately 45° with respect to
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the vertical reference. Further, in accordance with the
preferred embodiment, additional press roll 14 may be
located below suction press roll 4 such that a straight
line extending through the axes of suction press roll 4 and
additional press roll 14 substantially forms a right angle
with the line formed by the collinear arrangement of the
rolls.
In an alternative embodiment illustrated in Figure 2,
additional press roll 24 may rotated out of collinear
arrangement of Figure 1 to be located directly above pay
out press roll 7, with respect to a machine foundation 44.
Thus, a straight line extending through the axes of pay-out
press roll 7 and additional press roll 24 may be
substantially vertical with respect to machine foundation
44. Generally, in all other respects the roll press
illustrated in Figure 2 is substantially similar to the
roll press depicted in Figure 1, thus, same reference
numerals have bee associated to similar elements.
Therefore, in accordance with the respective seating
of the rolls as shown in the alternative embodiment of
Figure 2, pay-out press roll 7 may be fixed in a defined
position, i.e., substantially without any radial
deflection, on a stanchion (upright support beam) 42 which
may be fixedly mounted fixed on machine foundation 44.
At least during operation of the roll press, the
jacket of pay-out press roll 7 may be substantially
radially fixed at its ends to maintain a substantially
unchanged position even under a pressure load.
A position adjustment may be utilized to ensure that
press gap S remains in its preset position. Thus, press
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gap S is held in position independently of the respective
pressure force and the respective machine speed. At least
one position sensor and at least one pressure force
regulating device may be provided for at least one of the
respective support elements.
As illustrated in Figures 2 and 3, during operation of
the roll press, press rolls 4, 7, 14 and 24 forming the
three press gaps may be supported against each other and/or
connected to each other, with regard to forces, such that
practically no pressing forces need to be absorbed by other
seating elements. That is, the pressing forces may be
absorbed by the associated bearing parts supporting the
roll journals or the roll cores.
The respective courses of the force flow, illustrated
in bold lines (solid and dashed) in Figure 3, may result in
the region of the three press gaps. Accordingly, force
lines closed in themselves result above the respective
press gaps, which leads to the fact that the pressing
forces which, as a rule, are relatively high, only need to
be absorbed by the associated bearing elements supporting
the roll journals or the cores. That is, the force lines
associated with gap R, gap B, and gap S run through the
centers of the respective bearings and through the
respective centers of the press gaps. Therefore,
additional bearing elements need not be laid out for these
high pressing forces.
The roll press of the present invention may include
connecting elements provided between the bearing places to
releasably couple the rolls together. Further, the rolls
may be released, e.g., to enable changing the rolls or
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coverings.
The roll press in Figure 2 may be illustrated, e.g.,
during a phase in which press felt 6 is being changed, as
shown in Figure 4. Figure 4 shows suction press roll 4 in
a released state, i.e., not abutting screen 1, additional
press roll 14, and pay-out press roll 7 through press felt
6. Press felt 6 may be freely supported by a cantilever
carrier 46 on the guide or operator side, and it may be
supported on the drive side. To loosen press felt 6 for
changing, intermediate pieces 48 (associated with suction
press roll 4 and shown in Figure 2) may be removed, e.g.,
by lifting the bearing arrangement located above it with a
crane.
In accordance with Figure 4, press felt 6, which was
clamped on a deflection roll 50 as shown in Figure 2, may
be partially wound onto a roll 52.
Figure 5 shows the roll press of Fig. 2 during a phase
in which press felt 25 is being changed. Prior to changing
press felt 25, intermediate pieces 48 (associated with
additional press roll 24 and shown in Figure 2) may be
removed.
To change press felt 25, the connecting elements of
additional press roll 24 and pay-out press roll 7 and the
seating elements on the guide side may be released.
Thereafter, additional press roll 24 may be lifted by a
support device fastened on its core, around which the felt
had previously been draped.
In accordance with Figure 5, press felt 25, which was
previously clamped on a deflection roll 54, as shown in
Figure 2, and which is now being change, may be partially
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wound onto a roll 56.
The frame seating may be exclusively provided for
supporting the felt running devices and for receiving the
inherent weight of the pressing installations. Thus, the
frame seating is not used to absorb pressing forces exerted
on the material web.
The frame seating may be integrated into a forming and
screen section disposed upstream, with respect to the
travel direction of the material web. For performing a
screen change, appropriate interrupting devices may be
provided on the guide side. In this case, the frame
seating may be supported on the guide side by the
cantilever carrier of suction press roll 4.
In accordance with the present invention, the entire
pressing arrangement may not include seating elements on
machine foundation 44 in front of the machine. That is,
the machine may be free of such seating elements in front
of the machine girder on the guide side, on which the frame
stanchion and the stanchion of the pay-out press roll are
supported.
In accordance with Figure 6, when changing press felt
15, after releasing the connecting elements on the guide
side, additional press roll 14 may be lowered by a support
device fastened on the core of the press roll 14, around
which the new felt had been previously draped. The support
device may be, e.g., a push-on tube.
The roll press can have a crane rail for a respective
roll change, which extends transversely with respect to the
paper machine and may perform various functions. For
example, crane rail 58 (Figure 3) may be intended for use
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P15457.S02
as an extension aid for supporting the end of suction press
roll 4 on the drive side. It may also be used as an
insertion aid for supporting the end of the felt insertion
device on the drive side for press felt 6 associated with
suction press roll 4. It may also be used as an insertion
aid for supporting the end of the felt insertion device on
the drive side for press felt 25, which may be guided
around additional press roll 24.
The roll press, in accordance with the features of the
present invention, has the advantage that a closed web
guide results from a pick-up place at a screen side of the
machine to an end of the roll press. Overall, not much re
wetting is permitted, which ensures the highest degree of
dry content for the material web. Because there are no
open sections inside the press, no stretching of the paper
and no loss of wet strength occurs. The first open section
may be located downstream of the roll press at maximum wet
strength. The highest degree of wet strength may be
ensured because only one transfer point downstream of the
press section is provided.
Even with a production width variation, it may be
possible to always ensure a constant paper width through
each press gaps or nips. A variable edge strip may run off
a central roll. It is also important that the press felts
and press rolls may always be operated with the same paper
width. The desired high dry content may be achieved, e.g.,
with.only one press, which results in a reduced number of
rolls.
Further, an extremely compact structure or
construction of the roll press is available. Thus, in
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P15457.S02
addition to space savings, the present invention may be
essential, e.g., for problem-free retrofitting of
replacement components.
Because direct force flow may be provided for all
press gaps or nips, portal seating may be omitted and no
stanchions are provided on the outside of the drive side.
Accordingly, more free space may be created in front of the
machine and there is no load on the cover.
Furthermore, good access may be provided by bridge
seating. A respective felt or roll change may be possible
without problems. Further, improved accessibility may be
provided for adjustment, maintenance and cleaning
operations.
Due to the lack of a transverse support above the
press, an optimal nip arrangement, e.g., in the form of a
four-roll Nipco-Flex combination press, may be provided.
A stationary path run geometry downstream of the press
may result in a stationary driven central press roll (Nico-
P-roll) after the press roll has been mounted on a
stanchion. Furthermore, a locally stable scraper
embodiment may be utilized. Due to the specific
arrangement of the present invention, the roll press may
also be insensible to drive oscillations.
Further, a high degree of operational dependability
may result for a respective shoe press in an installment
position, such as that provided by the present invention.
The clotting danger may be reduced to a minimum by a closed
web removal. Manual application (e. g., by a glass tube)
may be omitted, the same as the two nips for pre
calibration. Optimal press jacket lubrication may be
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P15457.S02
utilized in the event of an inverted shoe arrangement.
A relatively simple press roll change may be possible
in spite of the compact construction. The press rolls may
be changed (or replaced) independently of each other with
little expenditure of time. Extension devices may be
provided for each press roll, which reduces the time
necessary of operating the crane to a minimum. However, a
roll change may be basically possible without a crane,
e.g., by rails located in front of the machine.
Press felt 6 associated with suction press roll 4 may
be fully cantilevered. That is, the felt can be changed
without problems by rails located in front of the machine.
Alternatively, press felt 6 associated with suction press
roll 4 may be fully cantilevered. That is, the felt may be
changed without problems by a felt change insertion device.
The upper felt may be portable by a press jacket
changing device. Again, a felt change insertion device may
be utilized. Further, the lower felt may be portable
(e. g., push-on tube on a Nipco core). Extensible felt
guide rolls located on the inside may be utilized.
In addition, improved accessibility for Scanpro
measurements may be achieved.
Finally, a cost-effective overall roll press concept
may be contemplated. For example, since a separate Nipco
Flex press is not necessarily provided in the construction
of the present invention, only a few reserve rolls may be
required. Further, a very small construction cost portion
may also result from the reduced space requirements.
It is noted that the foregoing examples have been
provided merely for the purpose of explanation and are in
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P15457.502
no way to be construed as limiting of the present
invention. While the invention has been described with
reference to a preferred 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
invention in its aspects. Although the invention has been
described herein with reference to particular means,
materials and embodiments, the invention is not intended to
be limited to the particulars disclosed herein; rather, the
invention extends to all functionally equivalent
structures, methods and uses, such as are within the scope
of the appended claims.
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P15457.502
Reference Numeral List
1 screen
2 screen roll
3 screen roll
4 suction press roll
6 press felt
7 pay-out press roll
8 vacuum
14 additional press roll
15 press felt
16 core
17 roll jacket
18 support element
24 additional press roll
25 press felt
26 roll jacket
27 support element
27' support element
30 roll jacket
32 core
34 suction box
36 region
38 roll jacket
40 support element
42 stanchion
44 machine foundation
46 cantilever carrier
48 intermediary pieces
50 deflection roll
52 roll
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P15457.502
54 deflection roll
56 roll
A paper web
B press gap
R additional press gap
S additional press gap
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