DISPOSITIF PRESSE

A PRESS APPARATUS

Abrégé français

L'invention concerne un dispositif presse (10) permettant d'exprimer de l'eau d'une bande continue formée (W). Ce dispositif comporte un cadre de presse et un rouleau central (12) maintenu rotatif par le cadre. Un rouleau (14) en amont coopère avec le rouleau central (12) de manière à définir entre aux une pince (N1) de rouleau destinée au passage de la bande continue. La disposition est telle qu'une première quantité d'eau est exprimée de la bande continue lorsque celle-ci passe à travers la pince (N1) du rouleau. Un premier sabot (16) de presse à pince allongée est placé en aval par rapport à la pince du rouleau. Ce premier sabot (16) définit une première surface concave coopérant avec le rouleau central (12) de manière à définir entre eux une première pince allongée (N2) destinée au passage de la bande continue compressée. La disposition est telle qu'une deuxième quantité d'eau est exprimée de la bande continue lorsque la bande continue compressée passe à travers la première pince allongée (N2). Un deuxième sabot (20) de presse à pince allongée est placé en aval par rapport au premier sabot (16). Le deuxième sabot (20) définit une deuxième surface concave coopérant avec le rouleau central (12) de manière à définir entre eux une deuxième pince allongée (N3) destinée au passage de la bande continue compressée. La disposition est telle qu'une troisième quantité d'eau est exprimée de la bande continue lorsque la bande continue compressée passe à travers la deuxième pince allongée (N3).

Abrégé anglais

A press apparatus (10) is disclosed for pressing water from the formed web
(W). The apparatus includes a press frame and a center roll (12) rotatably
supported by the frame. An upstream roll (14) cooperates with the center roll
(12) for defining therebetween a roll nip (N1) for the passage therethrough of
the web. The arrangement is such that a first portion of water is removed from
the web when the web extends through the roll nip (N1). A first extended nip
press shoe (16) is disposed downstream relative to the roll nip. The first
shoe (16) defines a first concave surface which cooperates with the center
roll (12) for defining therebetween a first extended nip (N2) for the passage
therethrough of the pressed web. The arrangement is such that a second portion
of water is removed from the web when the pressed web extends through the
first extended nip (N2). A second extended nip press shoe (20) is disposed
downstream relative to the first shoe (16). The second shoe (20) defines a
second concave surface which cooperates with the center roll (12) for defining
therebetween a second extended nip (N3) for the passage therethrough of the
pressed web. The arrangement is such that a third portion of water is removed
from the web when the pressed web extends through the second extended nip (N3).

Revendications

8
WHAT IS CLAIMED IS:
1. A press apparatus for pressing water from the formed web,
said apparatus comprising:
a press frame;
a center roll rotatably supported by said frame;
an upstream roll cooperating with said center roll for defining
therebetween a roll nip for the passage therethrough of the
web, the arrangement being such that a first portion of water
is removed from the web when the web extends through said
roll nip;
a first extended nip press shoe disposed downstream relative to said
roll nip, said first shoe defining a first concave surface which
cooperates with said center roll for defining therebetween a
first extended nip for the passage therethrough of the pressed
web, the arrangement being such that a second portion of
water is removed from the web when the pressed web
extends through said first extended nip; and
a second extended nip press shoe disposed downstream relative to
said first shoe, said second shoe defining a second concave
surface which cooperates with said center roll for defining
therebetween a second extended nip for the passage
therethrough of the pressed web, the arrangement being such
that a third portion of water is removed from the web when
the pressed web extends through said second extended nip.
2. A press apparatus as set forth in claim 1 wherein said press
frame rotatably supports said upstream roll.
3. A press apparatus as set forth in claim 1 wherein said center
roll comes into direct surface contact with a first side of the web.

9
4. A press apparatus as set forth in claim 1 wherein said center
roll is a deflection compensated roll.
5. A press apparatus as set forth in claim 1 further including:
a press felt which extends through said roll nip, the arrangement
being such that the web is disposed between said press felt
and said center roll during passage of the web through said
first roll nip.
6. A press apparatus as set forth in claim 1 further including:
a looped bearing blanket slidably cooperating with said first press
shoe, said bearing blanket supporting and guiding the web
during passage of the web through said first extended nip, the
arrangement being such that the web is disposed between
said bearing blanket and said center roll during passage of the
web through said first extended nip.
7. A press apparatus as set forth in claim 6 wherein a first side
of the web comes into direct surface contact with said center roll during
passage of the web through said first extended nip.
8. A press apparatus a set forth in claim 6 wherein:
said bearing blanket slideably cooperates with said second press
shoe, said bearing blanket supporting and guiding the web
during passage of the web through said second extended nip.
9. A press apparatus as set forth in claim 1 wherein:
a first side of the web comes into direct surface contact with said
center roll during passage of the web through said second
extended nip.

10
10. A press apparatus a set forth in claim 1 further including:
a lead-in roll disposed down relative to said second extended nip;
a dryer felt extending around said lead-in roll, the arrangement being
such that the web is transferred from said center roll to said
dryer felt downstream from said second extended nip.

Description

CA 02325905 2000-09-25
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TITLE: A PRESS APPARATUS
The present invention relates to a press apparatus for pressing water
from a formed web.
More specifically, the present invention relates to an extended nip
press apparatus for pressing water from a formed web.
A formed web typically has between 50 to 90 percent water therein.
Consequently, a large proportion of such water is removed from the web
by pressing the web.
Typically, a formed web is guided between a pair of counter rotating
rolls which define therebetween a press nip. The press nip presses water
from the web so that the web can be guided towards a drying section in
which the web extends around a plurality of heated drying cylinders which
remove most of the remaining water therefrom.
More recently, extended nip press arrangements have been
commercialized for removing greater quantities of water from the web prior
to guiding the web around the heated drying cylinders.
Extended nip press arrangements typically include a backing roll and
a press shoe having a concave surface which cooperates with the backing

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roll for defining therebetween an extended nip for the passage therethrough
of the web.
The present invention includes a combination of a typical roll couple
press followed by a first and second extended nip press.
However, the present invention is unique in that the press apparatus
includes a center roll which is common to the roll nip and both of the
extended nips. Such an arrangement greatly reduces the overall cost of the
press apparatus so that only one deflection compensated center roll is
required.
Other objects and advantages of the present invention will be readily
apparent to those skilled in the art by a consideration of the detailed
description contained hereinafter taken in conjunction with the annexed
drawings.
The present invention relates to a press apparatus for pressing water
from a formed web. The apparatus includes a press frame and a center roll
which is rotatably supported by the frame.
An upstream roll cooperates with the center roll for defining
therebetween a roll nip for the passage therethrough of the web. The
arrangement is such that a first portion of water is removed from the web
when the web extends through the roll nip.
An extended nip press shoe is disposed downstream relative to the
roll nip. The first shoe defines a first concave surface which cooperates
with the center roll for defining therebetween a first extended nip for the

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passage therethrough of the pressed web. The arrangement is such that a
second portion of water is removed from the web when the pressed web
extends through the first extended nip.
A second extended nip press shoe is disposed downstream relative
to the first shoe. The second shoe defines a second concave surface
which cooperates with the center roll for defining therebetween a second
extended nip for the passage therethrough of the pressed web. The
arrangement is such that a third portion of water is removed from the web
when the pressed web extends through the second extended nip.
In a more specific embodiment of the present invention, the press
frame rotatably supports the upstream roll.
Also, the center roll comes into direct surface contact with a first
side of the web.
Additionally, the center roll is a deflection compensated roll.
The press apparatus according to the present invention also includes
a press felt which extends through the first roll nip. The arrangement is
such that the web is disposed between the press felt and the center roll
during passage of the web through the roll nip.
Furthermore, the press apparatus according to the present invention
includes a looped bearing blanket which slidably cooperates with the first
press shoe. The bearing blanket supports and guides the web during
passage of the web through the first extended nip. The arrangement is
such that the web is disposed between the bearing blanket and the center
roll during passage of the web through the first extended nip.

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More specifically, a first side of the web comes into direct surface
contact with the center roll during passage of the web through the first
extended nip.
Also, the bearing blanket slidabiy cooperates with the second press
shoe. The bearing blanket supports and guides the web during passage of
the web through the second extended nip. More specifically, the first side
of the web comes into direct surface contact with the center roll during
passage of the web through the second extended nip.
Additionally, a lead-in roll is disposed downstream relative to the
second extended nip and a dryer felt extends around the lead-in roll. The
arrangement is such that the web is transferred from the center roll to the
dryer felt downstream from the second extended nip.
Many modifications and variations of the present invention will be
readily apparent to those skilled in the art by a consideration of the
detailed
description contained hereinafter taken in conjunction with the annexed
drawings. However, such modifications and variations fall within the spirit
and scope of the present invention as defined by the appended claims.
Fig. 1 is a diagrammatic representation of the press apparatus
according to the present invention.
Fig. 2 is a side elevational view of a preferred embodiment of the
present invention.
Similar reference characters refer to similar parts throughout the best
view of the drawings.

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DETAILED ESCRIPTION OF THE DRAWINGS
Fig. 1 ~is a diagrammatic representation of a press apparatus 10 for
pressing water from a formed web W.
As shown in Fig. 1, the apparatus 10 includes a press frame and a
center roll 12 which is rotatably supported by the frame.
An upstream roll 14 cooperates with the center roll 12 for defining
therebetween a roll nip N 1 for the passage therethrough of the web W.
The arrangement is such that a first portion of water is removed from the
web W when the web extends through the roll nip N1.
A first extended nip press shoe 16 is disposed downstream relative
to the roll nip N 1. The first shoe 16 defines a first concave surface 18
which cooperates with the center roll for defining therebetween a first
extended nip N2 for the passage therethrough of the pressed web W. The
arrangement is such that a second portion of water is removed from the
web W when the pressed web W extends through the first extended nip
N2.
A second extended nip press shoe 20 is disposed downstream
relative to the first shoe 16. The second shoe 20 defines a second
concave 22 surface which cooperates with the center roll 12 for defining
therebetween a second extended nip N3 for the passage therethrough of
the pressed web W.
The arrangement is such that a third portion of water is removed
from the web when the pressed web extends through the second extended
nip N3.

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Fig. 2 is a more detailed side elevational view of the preferred
embodiment of the present invention. As shown in Fig. 2, the frame 24
rotatably supports the upstream roll 14 and the center roll 12 comes into
direct surface contact with a first side 26 of the web W.
Preferably, the center roll 12 is a deflection compensated roll
otherwise known as a crown compensated roll.
The press apparatus 10 also includes a press felt F which extends
through the roll nip N 1. The arrangement is such that the web W is
disposed between the press felt F and the center roll 12 during passage of
the web W through the roll nip N 1.
A looped bearing blanket 28 slidably cooperates with the first press
shoe 16. The bearing blanket supports 28 and guides the web W during
passage of the web W through the first extended nip N2. The arrangement
is such that the web W is disposed between the bearing blanket 28 and the
center roll 12 during passage of the web W through the first extended nip
N2.
As is well known in the art, the first extended nip N2 includes a
press felt 30 disposed between the bearing blanket 28 and the web W.
Alternatively, the extended nip N2 may be double felted in which a press
felt is disposed on both sides of the web W during passage through the
first extended nip N2.
In a preferred embodiment of the present invention, the first side 26
of the web W comes into direct surface contact with the center roll 12
during passage of the web W through the first extended nip N2. In the
aforementioned arrangement, only one press felt 30 is included and such

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press felt is disposed between the bearing blanket 28 and the first press
shoe 16.
Additionally, the bearing blanket 28 slidably cooperates with the
second press shoe 20. The bearing blanket 28 supports and guides the
web W during passage of the web W through the second extended nip N3.
In the arrangement shown in Fig. 2, the first side 26 of the web W
comes into direct surface contact with the center roll 12 during passage of
the web W through the second extended nip N3.
Additionally, the press apparatus as shown in Fig. 2 includes a lead-
in roll 32 which is disposed downstream relative to the second extended
nip N3.
Also, a dryer felt 34 extends around the lead-in roll 32, the
arrangement being such that the web W is transferred from the center roll
12 to the dryer felt 34 downstream from the second extended nip N3.
The present invention provides an extremely compact press
arrangement which not only enables the removal of a considerably amount
of water from the web prior to the web being guided through the dryer
section but also eliminates the need for more than one compensated center
roll.