Information
-
Patent Grant
-
6743334
-
Patent Number
6,743,334
-
Date Filed
Tuesday, June 11, 200222 years ago
-
Date Issued
Tuesday, June 1, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 162 118
- 162 283
- 162 3591
- 162 361
- 034 114
- 034 534
- 034 132
- 034 123
- 034 71
- 034 444
- 242 1601
- 242 370
-
International Classifications
-
Abstract
A dry end section for a paper-making machine for producing a high-bulk tissue is provided. Such a machine comprises a through-air dryer adapted to finally dry a paper web and a through-air drying fabric configured to transport the web through the through-air dryer. A separating device is included for facilitating separation of the web from the through-air drying fabric. A reel is also provided and is configured to receive the web thereon. The web is received directly on the separating device or on a fabric wrapped about the separating device. In some instances, the web may be compressed between the separating device and an adjacent roll or by a web-compressing device disposed along the fabric transporting the web. The web is then transported to the reel directly from the fabric or other support mechanism extending between the separating device and the reel, without free draw of the web. Associated methods are also provided.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to paper-making machinery and, more particularly, to a paper-making machine and associated method for making a tissue paper with improved tactile qualities while improving the reel-up process.
2. Description of Related Art
In the production of tissue for use in personal hygiene products and the like, it is desired to produce a tissue with good tactile qualities (i.e., silky and soft to the touch) while also achieving a high machine speed and efficiency. The speed and efficiency are often limited by the performance of the dry end of the machine between the final dryer and the winding station or reel-up. Tissue is extremely delicate and difficult to handle, especially at high machine speeds. For example, in some instances, the tissue web is dried by a through air dryer (“TAD”), wherein a through air drying fabric (“TAD fabric”) is used to transport the web through the TAD. The TAD fabric is generally an open structured drying fabric. Accordingly, the web will tend to become drawn into the structure of the TAD fabric as the web is processed through the TAD and other processing devices such as, for instance, a molding device, in order to produce a structured three-dimensional fiber network. However, separating the tissue web from the TAD fabric without damaging the web then becomes a difficult and sensitive task.
In addition, due to the generally delicate nature of the tissue web, excessive transfers and handling of the web in the dry end of the machine may result in damage to the web. Such detrimental results may also occur if the web is unsupported between components within the dry end. Further, if a bulky tissue web is produced in the paper-making process, the capacity of the roll on which the web is wound may be undesirably low since the web cannot be tightly wound onto the roll. A loosely wound roll is relatively more difficult to handle and may be undesirably prone to, for example, telescoping with respect to the roll.
Thus, there exists a need for a method and apparatus directed to a dry end of a tissue paper-making machine for making a tissue web providing improved tactile qualities while improving the handling of the tissue web in the dry end. Such an apparatus and method should desirably be capable of addressing the issue of separating the tissue web from a TAD fabric efficiently and at high speed, but without damage. Further, such an apparatus and method should provide for minimal transfers and other handling of the tissue web while providing support for the tissue web throughout the dry end. In addition, the apparatus and method should be directed to reducing the bulk of the tissue web, again with minimal handling and while providing the desired improved tactile quality, in order to increase roll capacity and facilitate handling of the rolls.
BRIEF SUMMARY OF THE INVENTION
The above and other needs are met by the present invention which, in one embodiment, provides a dry end section for a paper-making machine for producing a high-bulk tissue. Such a machine includes a through-air dryer adapted to finally dry a paper web and a through-air drying fabric configured to transport the web through the through-air dryer. A separating device is also included for facilitating separation of the web from the through-air drying fabric, and the machine comprises a reel configured to, receive the web. A single permeable fabric is wrapped about the separating device and extends to the reel, wherein the single permeable fabric is configured to receive the web directly thereon from the through-air drying fabric and to transport the web directly to the reel without free draw of the web.
Another advantageous aspect of the present invention comprises a dry end section for a paper-making machine for producing a high-bulk tissue. Such a machine includes a through-air dryer adapted to finally dry a paper web and a through-air drying fabric configured to transport the web through the through-air dryer. A separating device is further included for separating the web from the through-air drying fabric such that the web is received directly on the separating device. A roll is disposed adjacent to the separating device so as to define a nip therebetween and to form a web-compressing device. A single fabric is wrapped about the roll, passes through the nip, and extends to a reel configured to receive the web, wherein the single fabric is configured to receive the web thereon at the nip and to transport the web from the nip to the reel, at which point the web is transferred directly from the single fabric to a reel without free draw of the web.
Still another advantageous aspect of the present invention comprises a dry end section for a paper-making machine for producing a high-bulk tissue. Such a machine includes a through-air dryer adapted to finally dry a paper web and a through-air drying fabric configured to transport the web through the through-air dryer. A separating device is also included for separating the web from the through-air drying fabric, wherein the separating device is configured to receive the web directly thereon. A reel having a reel drum disposed adjacent thereto forms a reel-up for receiving the web from the separating device. A non-contacting support system is disposed between the separating device and the reel-up, wherein the non-contacting support system is configured to receive the web directly from the separating device and to transport the web directly to the reel-up.
Yet other advantageous aspects of the present invention comprise methods for making a tissue with enhanced tactile quality and facilitating reel-up of the tissue in a dry end of a tissue paper-making machine, each method corresponding to the processing of a tissue web with the respective dry end section for a paper-making machine for producing a high bulk tissue as described herein, as will be appreciated by one skilled in the art.
Thus, embodiments of the present invention provide a method and apparatus directed to a dry end of a tissue paper-making machine for making a tissue web providing improved tactile qualities while improving the handling of the tissue web in the dry end. Embodiments of the present invention further address the issue of separating the tissue web from a TAD fabric efficiently and at high speed, but without damage and while minimizing transfers and other handling of the tissue web, by using a suction roll for separating the web from the TAD fabric, wherein the suction roll is disposed adjacent to an additional roll to also form a web-compressing device. The web is then wound directly onto the roll or transported directly thereto by a single fabric passing through the web-compressing device. Accordingly, support is provided for the tissue web throughout the dry end, and runability of the dry end is facilitated, while the bulk of the tissue web is reduced in order to provide increased roll capacity and more efficient handling of the rolls. In addition to improving the tactile quality of the tissue web, embodiments of the present invention reduce the number of fabrics, and components associated therewith, used in the dry end, thereby simplifying the paper-making machine, reducing the handling of the web, and reducing the cost and maintenance requirements of the machine. Therefore, the present invention provides distinct advantages as further detailed herein.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
FIG. 1A
is a cross-sectional schematic of a dry end section for a paper-making machine for producing a high-bulk tissue according to one embodiment of the present invention showing an inward flow TAD and a web-compressing device formed between a suction roll having a fabric wrapped thereabout and an adjacent roll;
FIG. 1B
is a cross-sectional schematic of a dry end section for a paper-making machine for producing a high-bulk tissue according to one embodiment of the present invention showing an outward flow TAD and a web-compressing device formed between a suction roll having a fabric wrapped thereabout and an adjacent roll;
FIG. 2
is a cross-sectional schematic of a dry end section for a paper-making machine for producing a high-bulk tissue according to an alternate embodiment of the present invention showing an inward flow TAD and a web-compressing device formed between a suction roll having a fabric wrapped thereabout and an adjacent roll;
FIG. 3
is a cross-sectional schematic of a dry end section for a paper-making machine for producing a high-bulk tissue according to another alternate embodiment of the present invention showing a web-compressing device formed about the web along the dry end section between the suction roll and the reel;
FIGS. 4 and 5
are cross-sectional schematics of still further alternate embodiments of the present invention, each showing a dry end section for a paper-making machine for producing a high-bulk tissue having a web-compressing device formed between a suction roll and an adjacent roll having a fabric wrapped thereabout; and
FIG. 6
is a cross-sectional schematic of yet another alternate embodiment of the present invention showing a dry end section for a paper-making machine for producing a high-bulk tissue, the dry end section including an inward flow TAD and the web being transported between a suction roll and a reel nip by air devices.
DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
FIGS. 1A-B
,
2
, and
3
schematically illustrate embodiments of a dry end of a paper-making machine, the dry end being indicated by the numeral
10
, according to the present invention. The dry end
10
includes at least one through air dryer (“TAD”)
20
configured to finally dry a tissue paper web
30
. Though the embodiments of the present invention are generally described herein in terms of a single TAD
20
, the dry end
10
may include a plurality of through-air dryers. Further, one skilled in the art will appreciate that the web
30
may be pre-dried or otherwise processed through other dryers before being transferred to the TAD
20
. For example, the web
30
may be pre-dried on a Yankee dryer (not shown) and then creped therefrom before being transferred to a TAD
20
for final drying. In other instances, the web
30
may be pre-dried by another type of dryer such as, for example, an impingement dryer (not shown). Thus, embodiments of the present invention describing a dry end
10
are not intended to be restrictive with respect to the processing of the web
30
prior to the web
30
being finally dried by the through air dryer
20
.
As shown in
FIGS. 1A
,
2
, and
3
, the TAD
20
may be configured to have an inward flow or, in some instances, to have an outward flow if the drying air, as shown in FIG.
1
B. Accordingly, one skilled in the art will appreciate that any of the embodiments described herein may implement either an inward flow TAD or an outward flow TAD within the spirit and scope of the present invention. As such, it will be understood that both TAD alternatives are expressly included herein for each embodiment of the present invention, even though both TAD alternatives may not be specifically mentioned or illustrated. The TAD
20
is further configured to have a through air drying fabric (“TAD fabric”)
40
wrapped thereabout for receiving the web
30
thereon and transporting the web
30
through the TAD
20
. In some cases, a transfer device
50
may be disposed adjacent to the TAD fabric
40
about where the web
30
is received in order to facilitate the transfer of the web
30
onto the TAD fabric
40
. The TAD fabric
40
is generally an open structured drying fabric and the web
30
will tend to become drawn into the structure of the TAD fabric
40
as the web
30
is processed through the TAD
20
and other processing devices such as, for instance, a molding device
60
which, in one embodiment, is disposed before the TAD
20
and adjacent to the TAD fabric
40
. Such a molding device
60
is configured to impart suction on the web
30
through the TAD fabric
40
so as to draw the web
30
into the fabric structure and form a structured three-dimensional fiber network. According to one embodiment of the present invention, the finally-dried web
30
has a basis weight of between about 10 g/m
2
and about 50 g/m
2
and a dry caliper of between about 0.2 mm and about 0.5 mm, and thus a density of between about 20 kg/m
3
and about 250 kg/m
3
, after leaving the TAD
20
.
A tissue web
30
is extremely delicate and difficult to handle, especially at high machine speeds. As such, following the drying process, it is typically difficult to separate the tissue web
30
from a TAD fabric
40
into which the web
30
has become drawn. Further, a tissue web
30
is at less risk of damage if handled by fewer machine components and is supported (i.e., not subjected to free draw) during the drying process. Thus, according to one advantageous aspect of the present invention, the web
30
is separated from the TAD fabric
40
, following final drying of the web
30
by the TAD
20
, by a separating device
90
having a permeable fabric
130
wrapped thereabout. The separating device
90
may comprise, for example, a suction-configured reel drum or a suction roll (referred to herein as “suction roll
90
”) for separating the web
30
from the TAD fabric
40
. More particularly, the TAD fabric
40
is guided about the TAD
20
by a plurality of turning rolls
100
. Following final drying of the web
30
by the TAD
20
, the TAD fabric
40
is directed so as to run tangentially to the suction roll
90
so as to define a web transfer point
110
between the TAD fabric
40
and the permeable fabric
130
. Thus, the suction roll
90
imparts suction through the permeable fabric
130
, as discussed below, so as to facilitate the transfer of the web
30
thereto. Further, in order to facilitate the running of the web
30
through the described dry end
10
and separation of the web
30
from the TAD fabric
40
, an air-emitting device
120
such as, for example, an air knife or an air shower, may be disposed adjacent to the TAD fabric
40
about the web transfer point
110
. The air-emitting device
120
is directed/configured to emit air through the TAD fabric
40
and against the web
30
so as to provide assistance in separating the web
30
from the TAD fabric
40
only as the web
30
is initially being threaded through the dry end
10
.
Accordingly, the leading edge of the web
30
is first separated from the TAD fabric
40
by the suction roll
90
in conjunction with the air-emitting device
120
, wherein the permeable fabric
130
is configured to allow the suction roll
90
to apply the suction therethrough to the tissue web
30
. Once the web
30
is separated from the TAD fabric
40
, the web
30
is received directly on the permeable fabric
130
and the air-emitting device
120
is deactivated. The permeable fabric
130
then solely transports the web
30
from the suction roll
90
to the reel
70
. That is, in advantageous embodiments of the present invention, only one permeable fabric
130
extends from the suction roll
90
to the reel
70
and only that permeable fabric
130
contacts and supports the web
30
therebetween. The web
30
is further transported from the TAD fabric
40
to the reel
70
without free draw. As such, once the web
30
is dried and separated from the TAD fabric
40
, the web
30
is wound onto a reel
70
with minimal handling. More particularly, as shown in
FIGS. 1A and 1B
, the permeable fabric
130
wraps about the separating device
90
and about one or more turning rolls
100
such that the permeable fabric
130
runs adjacent to the reel
70
and tangentially thereto. In such a configuration, the permeable fabric
130
supports the reel
70
during the winding process, forming a “soft nip” therewith, wherein the pressure in the soft nip may be selectively controlled so as to control the tension in the web
30
as it is wound onto the reel
70
.
In instances where a high bulk tissue web
30
is produced, such a web
30
, for example, may lessen the capacity of a roll, may be more difficult to handle, and may be prone to telescoping on the roll. Accordingly, it may be advantageous to reduce the bulk of the web
30
prior to winding the web
30
onto the roll. Compressing the web
30
in order to reduce the bulk thereof is usually accomplished through the use of a compression device defining a compression nip between adjacent rolls. Such a compression device comprises, for example, a calender used in the manufacture of card stock. However, due to the fragile nature of the tissue web
30
, it is very difficult to thread an unsupported tissue web through such a compression device. In addition, a calender used in the production of card stock is typically configured to impart smoothness or gloss to the card stock surface, which is not necessarily desired with a tissue paper. For a tissue paper, a good tactile quality, softness, and silkiness are some of the more desirable characteristics.
As shown in
FIGS. 1A and 1B
, a roll
140
may be added and disposed adjacent to the suction roll
90
so as to form a web-compressing device defining a nip
150
therebetween. Such a nip
150
may be adjustable to provide the necessary pressure for compressing the web
30
, which, in one embodiment, is a linear load of between about 200 N/m and about 800 N/m that reduces the web
30
in thickness by about 20% to about 50% with respect to the pre-compressed thickness of the web
30
. Since the web
30
is received directly on the permeable fabric
130
from the TAD fabric
40
, the permeable fabric
130
supports and transports the web
30
through the nip
150
. The roll
140
may be similar to a calender roll in that the surface thereof may be smooth. In the alternative, the surface of the roll
140
may also be patterned if a patterned structure is desired in the final web
30
.
However, when the web
30
is transported through a nip, the tendency of the web
30
will be to follow the smoother surface upon exiting the nip. Thus, the separating device
90
may also be configured to facilitate running of the web
30
. For example, the suction roll
90
may comprise a perforated outer shell or mantle with one or more air devices disposed inside the mantle and in spaced apart relation with respect thereto. Such air devices may be configured according to the needs of the particular application and, for example, may be adjustable within the mantle or rotatable about the axis of the suction roll
90
to further facilitate adjustment of the suction roll
90
for different processes. The air devices may further be configured to provide suction or to emit air outwardly therefrom, as necessary. As such, the mantle and the air devices may be arranged such that suction or emitted air can be selectively provided along the circumference of the mantle and/or laterally across the mantle while the mantle is rotating and transporting the web
30
. For example, since it is desired to maintain the web
30
on the permeable fabric
130
through the nip
150
and to the reel
70
, one or more air devices may be placed within the mantle of the suction roll
90
to provide suction along the circumference of the mantle from the web transfer point
110
to after the nip
150
so as to maintain the web
30
on the permeable fabric
130
therebetween.
In some situations, the necessary suction through the mantle of the suction roll
90
, and the permeable fabric
130
, may vary depending on the position of the web
30
with respect thereto. For example, suction is required about the web transfer point
110
to separate the web
30
from the TAD fabric
40
and to transfer the web
30
to the permeable fabric
130
. However, a higher suction may be initially required when the leading edge of a new web
30
is to be separated from the TAD fabric
40
, wherein the air-emitting device
120
may be simultaneously activated to facilitate the initial transfer of the web
30
to the permeable fabric
130
. In one embodiment, such a higher suction may be on the order of, for example, 30 kPa. After the initial threading of the web
30
, a lesser suction may be required to maintain the web
30
on the suction roll
90
and the permeable fabric
130
, from the web transfer point
110
and through the reel nip
150
. In one embodiment, such a lesser suction maybe on the order of, for example, 5-10 kPa. Still further, in some instances, the air devices may be configured with respect to the mantle so as to provide suction or air emission across the entire width, or at one or more selected zones across the width of the mantle, the selected zones thereby providing the necessary characteristic for the corresponding segment of the mantle while, for example, reducing the required volume capacity of the air devices. Accordingly, the air devices may be appropriately and selectively controlled to provide the necessary conditions for the web
30
about the mantle of the suction roll
90
.
As shown in
FIG. 2
, a reel drum
160
may disposed adjacent to the reel
70
so as to form a reel nip
170
therebetween. In this manner, the reel drum
160
supports the reel
70
and thus comprises an alternate configuration for facilitating the winding the web
30
onto the reel
70
. A single permeable fabric
130
extends about the suction roll
90
, the reel drum
160
, and one or more turning rolls
100
such that only the single permeable fabric
130
transports the web
30
from the suction roll
90
to the reel
70
without free draw of the web
30
. That is, the single permeable fabric
130
extends about the suction roll
90
and cooperates therewith to separate the web
30
from the TAD fabric
40
. The permeable fabric
130
then receives the web
30
directly thereon and supports and transports the web
30
through the nip
150
of the web-compressing device formed between the suction roll
90
and the adjacent roll
140
. The suction roll
90
is further configured to provide suction along the mantle thereof from the web transfer point
110
to after the nip
150
for maintaining the web
30
on the permeable fabric
130
through the nip
150
. Following the nip
150
, one or more air devices
180
may be disposed adjacent to the permeable fabric
130
so as to facilitate runability. More particularly, the air device(s)
180
may be configured so as to retain the web
30
on the permeable fabric
130
as a new web
30
is being threaded into the dry end
10
. The air device(s)
180
may comprise, for example, a blowing device, such as a blow box, capable of creating a low pressure effect for retaining the web
30
on the permeable fabric
130
. In addition, one or more measuring devices
190
such as, for example, a scanner, may be disposed adjacent to the web
30
, opposite to the permeable fabric
130
, for measuring web properties such as, for instance, the thickness thereof, wherein such measurement devices
190
will be known and appreciated by one skilled in the art. The web
30
is then directed through the reel nip
170
and wound onto the reel
70
.
FIG. 3
illustrates an alternative embodiment to the embodiment shown in FIG.
2
. As shown, instead of having a roll
140
disposed adjacent to the suction roll
90
, a web-compressing arrangement may be provided. The web-compressing arrangement includes a first roll
142
a
disposed within the loop of the permeable fabric
130
opposite to the web
30
, wherein the first roll
142
a
is disposed between the suction roll
90
and the reel
70
. A second roll
142
b
having a press fabric
145
wrapped thereabout is disposed in opposing relation to the first roll
142
a
so as to form a nip
148
therebetween. The nip
148
is further formed such that the web
30
and the permeable fabric
130
pass therethrough, whereby the web
30
is compressed between the permeable fabric
130
and the press fabric
145
. Such a nip
148
may also be adjustable to provide the necessary pressure for compressing the web
30
to reduce the thickness thereof to the desired thickness.
Thus, the embodiments shown in
FIGS. 1A-B
,
2
, and
3
provide a compact dry end
10
, wherein the separating device
90
serves to separate the web
30
from the TAD fabric
40
while also serving as one of the rolls in a web-compressing device. Such a dry end
10
further allows the web
30
to be transferred from the TAD fabric
40
to the reel
70
without free draw. Minimal components forming the dry end
10
further provides a paper-making machine with a smaller footprint and also minimizes the necessary handling of the web
30
. In addition, the configuration of the suction roll
90
with a separate mantle and one or more air devices disposed therein allows the mantle to be selectively segmented into variable suction and variable air emission zones, while enabling, for example, a common suction roll
90
having a diameter of about 1000 mm to about 1400 mm to be used, thereby conserving costs with respect to the machine. The described embodiments thus contribute to provide improved runability of the web
30
without free draw so as to provide an improved dry end
10
for a paper-making machine.
FIGS. 4 and 5
illustrate further advantageous embodiments of the present invention. As shown, the suction roll
90
is configured to separate the web
30
from the TAD fabric
40
and to receive the web
30
directly thereon. The roll
140
is disposed adjacent to the suction roll
90
so as to form the web-compressing device, the rolls
90
,
140
defining the nip
150
therebetween. One skilled in the art will appreciate, however, that, in some instances, a turning roll
100
about which the TAD fabric
40
is wrapped may be disposed adjacent to the suction roll
90
so as to form a second nip as part of a double nip web-compressing device (not shown), wherein that turning roll
100
may, in some situations, be configured as an air-emitting device so as to facilitate the transfer of the web
30
to the suction roll
90
following the second nip. Following the nip
150
, the single fabric
130
is wrapped about the roll
140
and extends about one or more turning rolls
100
to support the reel
70
for winding the web
30
thereon. Accordingly, the web
30
is received directly on the suction roll
90
, wherein the suction roll
90
then transports the web
30
into the nip
150
. At the nip
150
, the web
30
is transferred to the fabric
130
, which thereafter supports and transports the web
30
to the reel
70
such that the web
30
is transported from the TAD fabric
40
to the reel
70
without free draw thereof. In order to retain the web
30
on the suction roll
90
between the web transfer point
110
and the nip
150
, the suction roll
90
may be configured to provide suction about the portion of the mantle extending therebetween, as previously described. Further, according to various embodiments of the present invention, the roll
140
may be configured for suction as described herein and the single fabric
130
may thus be permeable or, in the alternative, the roll
140
may be a solid roll and the single fabric
130
may be smooth and impermeable.
Though the suction from the suction roll
90
is intended to facilitate the transportation of the web
30
through the dry end
10
, separation of the web
30
from the TAD fabric
40
and transfer of the web
30
to the suction roll
90
, as well as direction of the web
30
into the nip
150
, may be further assisted by one or more blower devices
200
such as, for example, an air knife. More particularly, one air knife
200
may be directed toward the web transfer point
110
on the downstream side thereof to facilitate transfer of the web
30
onto the suction roll
90
, while another air knife
200
may be directed toward the nip
150
from the upstream side thereof in order to direct the web
30
into the nip
150
. In addition, in order to further concentrate the air streams emitted by the respective air knives
200
, as well as to protect the web
30
from the air streams, a suitably shaped screen
210
may be disposed between the portion of the suction roll
90
carrying the web
30
and the air knives
200
.
FIG. 6
illustrates another alternate embodiment, wherein the suction roll
90
is disposed adjacent to the TAD fabric
40
so as to separate the web
30
therefrom, wherein the web
30
is transferred directly onto the suction roll
90
. A reel drum
160
is disposed adjacent to the reel
70
so as to form a reel nip
170
therebetween. The web
30
is supported and transported between the suction roll
90
and the reel nip
170
by a non-contacting support system
220
comprising, for example, one or more air foils, wherein such air foils may be active or passive. The air foils
220
are configured and spaced so as to provide sufficient support for the web
30
until the web
30
is transferred onto the reel drum
160
and directed into the reel nip
170
. Such a configuration may be particularly advantageous, for example, for a dry end section
10
for a stronger tissue paper web
30
such as, for instance, for forming an industrial tissue or towel. Further, embodiments of the present invention implementing a non-contacting support system
220
allows a measurement device
190
, such as a scanner, to be disposed about either or both surfaces of the web
30
for measuring the desired web properties. In addition, in some embodiments, a web-compressing device may be implemented for compressing the web
30
. Such a web-compressing device comprises a pair of rolls
230
disposed in opposing relation about the web
30
, the rolls
230
defining a nip
240
with the web
30
passing through the nip
240
. In this manner, the web
30
is compression treated on both surfaces thereof. If the configuration shown in
FIG. 6
is appropriate for the desired paper-making process, then the elimination of a fabric between the suction roll
90
and the reel nip
170
, as well as the elimination of components associated with such a fabric, may result in significant cost savings.
According to one advantageous aspect of the present invention, in instances where the web
30
is processed through a web-compressing device, such as a nip having a linear load of between about 200 N/m and about 800 N/m, the dry caliper of the web
30
is reduced by between about 20% and about 50%. More particularly, the dry caliper of the web
30
is reduced to between about 0.15 mm and about 0.4 mm, such that the web
30
has a post-compression density of between about 25 kg/m
3
and about 333.3 kg/m
3
.
Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, the web-compressing device described in various embodiments of the present invention may be configured to form either a hard or a soft nip between the rolls comprising the device, wherein the rolls may be at ambient temperature or heated. For a soft nip web-compressing device, one of the rolls may have a cover comprised of a resilient material such as, for example, rubber. Further, a heated web-compressing device may be advantageous in achieving a more consistent thickness profile across the width of the web. In addition, one skilled in the art will appreciate that the present disclosure describes and otherwise supports methods associated with embodiments of the present invention such as, for instance, methods for making a tissue with enhanced tactile quality and facilitating reel-up of the tissue in a dry end of a tissue paper-making machine, as described and claimed herein. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims
- 1. A dry end section for a paper-making machine for producing a high-bulk tissue, said machine comprising:a through-air dryer adapted to finally dry a paper web; a through-air drying fabric configured to transport the web through the through-air dryer; a separating device for facilitating separation of the web from the through-air drying fabric; a reel configured to receive the web; and a single permeable fabric wrapped about the separating device and extending to the reel, the single permeable fabric being configured to receive the web directly thereon from the through-air drying fabric and to transport the web directly to the reel without free draw of the web.
- 2. A dry end section according to claim 1 further comprising a roll disposed adjacent to the separating device so as to define a nip therebetween, the nip having the single permeable fabric passing therethrough, and to form a web-compressing device configured to compress the web before winding the web onto the reel.
- 3. A dry end section according to claim 1 wherein the single permeable fabric is configured to support the reel so as to facilitate winding of the web onto the reel.
- 4. A dry end section according to claim 1 further comprising a reel drum disposed adjacent to the reel so as to form a reel nip therebetween with the single permeable fabric transporting the web through the reel nip, the reel drum being configured to support the reel so as to facilitate winding of the web onto the reel.
- 5. A dry end section according to claim 1 wherein the separating device is selected from the group consisting of a suction-configured reel drum and a suction roll.
- 6. A dry end section according to claim 1 wherein the separating device comprises a roll having a perforated mantle and a suction device disposed within the mantle in spaced apart relation with respect thereto, the suction device being configured to selectively provide a suction zone about the mantle.
- 7. A dry end section according to claim 6 wherein the suction device is adjustably disposed within the mantle.
- 8. A dry end section according to claim 6 wherein the mantle defines an axis and the suction device is disposed within the mantle so as to be rotatable about the axis.
- 9. A dry end section according to claim 1 wherein the separating device is configured to provide an adjustable suction for separating the web from the through-air drying fabric.
- 10. A dry end section according to claim 1 further comprising an air emission arrangement disposed adjacent to the separating device and configured to facilitate separation of the web from the through-air drying fabric.
- 11. A dry end section according to claim 1 further comprising a web-compressing device disposed between the separating device and the reel, the web-compressing device comprising a first roll disposed adjacent to the single permeable fabric opposite to the web, the web-compressing device further comprising a second roll having a press fabric wrapped thereabout, the second roll opposing the first roll so as to form a nip therebetween such that the press fabric extends through the nip, the single permeable fabric being configured to transport the web through the nip such that the web is compressed between the single permeable fabric and the press fabric before the web is received by the reel.
- 12. A dry end section for a paper-making machine for producing a high-bulk tissue, said machine comprising:a through-air dryer adapted to finally dry a paper web; a through-air drying fabric configured to transport the web through the through-air dryer; a separating device for separating the web from the through-air drying fabric, the separating device being further configured to receive the web directly thereon; a roll disposed adjacent to the separating device so as to define a nip therebetween and to form a web-compressing device; a reel configured to receive the web; and a single fabric configured to wrap about the roll, to pass through the nip, and to extend to the reel, the single fabric being configured to receive the web thereon at the nip and to transport the web from the nip to the reel, the web being transferred directly from the single fabric to the reel without free draw of the web.
- 13. A dry end section according to claim 12 wherein the separating device is selected from the group consisting of a suction-configured reel drum and a suction roll.
- 14. A dry end section according to claim 12 wherein the separating device comprises a roll having a perforated mantle and a suction device disposed within the mantle in spaced apart relation with respect thereto, the suction device being configured to selectively provide a suction zone about the mantle.
- 15. A dry end section according to claim 14 wherein the suction device is adjustably disposed within the mantle.
- 16. A dry end section according to claim 14 wherein the mantle defines an axis and the suction device is disposed within the mantle so as to be rotatable about the axis.
- 17. A dry end section according to claim 14 wherein the separating device is configured to provide an adjustable suction for separating the web from the through-air drying fabric.
- 18. A dry end section according to claim 14 further comprising an air emission arrangement disposed adjacent to the separating device and configured to facilitate separation of the web from the through-air drying fabric.
- 19. A dry end section according to claim 14 wherein the roll is a suction roll and the single fabric is a permeable fabric.
- 20. A dry end section according to claim 14 wherein the roll is a solid roll and the single fabric is at least one of a smooth fabric and an impermeable fabric.
- 21. A method for making a tissue with enhanced tactile quality and facilitating reel-up of the tissue in a dry end of a tissue paper-making machine, said method comprising:finally drying a tissue web on a through-air drying fabric with a through air dryer; separating the tissue web from the through-air drying fabric with a separating device having a single permeable fabric wrapped thereabout such that the tissue web is received directly on the single permeable fabric; transporting the tissue web to a reel with the single permeable fabric; and winding the tissue web onto the reel, the tissue web being received on the reel directly from the single permeable fabric without free draw of the tissue web.
- 22. A method according to claim 21 wherein separating the tissue web from the through-air drying fabric further comprises separating the tissue web from the through-air drying fabric with a separating device, selected from the group consisting of a suction-configured reel drum and a suction roll, having a single permeable fabric wrapped thereabout.
- 23. A method according to claim 21 further comprising directing the tissue web and the single permeable fabric through a web-compressing device, the web-compressing device having a nip formed between the separating device and a roll disposed adjacent thereto, prior to winding the tissue web onto the reel.
- 24. A method according to claim 21 wherein separating the tissue web from the through-air drying fabric further comprises separating the tissue web from the through-air drying fabric with a separating device configured to apply suction to the tissue web through the single permeable fabric.
- 25. A method according to claim 24 wherein separating the tissue web from the through-air drying fabric with a separating device configured to apply suction to the tissue web through the single permeable fabric further comprises applying a greater suction to the tissue web when the tissue web is first separated from the through-air drying fabric and then applying a lesser suction to the tissue web thereafter.
- 26. A method for making a tissue with enhanced tactile quality and facilitating reel-up of the tissue in a dry end of a tissue paper-making machine, said method comprising:finally drying a tissue web on a through-air drying fabric with a through air dryer; separating the tissue web from the through-air drying fabric with a separating device such that the tissue web is received directly on the separating device; directing the tissue web through a web-compressing device having a nip formed between the separating device and a roll disposed adjacent thereto, the roll having a single fabric wrapped thereabout such that the tissue web is received on the single fabric at the nip; transporting the tissue web to a reel with the single fabric; and winding the tissue web on the reel, the tissue web being received on the reel directly from the single fabric without free draw of the tissue web.
- 27. A method according to claim 26 wherein separating the tissue web from the through-air drying fabric further comprises separating the tissue web from the through-air drying fabric with a separating device selected from the group consisting of a suction-configured reel drum and a suction roll.
- 28. A method according to claim 26 wherein separating the tissue web from the through-air drying fabric further comprises separating the tissue web from the through-air drying fabric with a separating device configured to apply suction to the tissue web.
- 29. A method according to claim 28 wherein separating the tissue web from the through-air drying fabric with a separating device configured to apply suction to the tissue web further comprises applying a greater suction to the tissue web when the tissue web is first separated from the through-air drying fabric and then applying a lesser suction to the tissue web thereafter.
- 30. A method of making a tissue with enhanced tactile quality and facilitating reel-up of the tissue in a dry end of a tissue paper-making machine, said method comprising:finally drying a tissue web, having a basis weight of between about 10 g/m2 and about 50 g/m2, on a through-air drying fabric with a through air dryer, the web having a dry caliper of between about 0.2 mm and about 0.5 mm and, therefore, a density of between about 20 kg/m3 and about 250 kg/m3; separating the tissue web from the through-air drying fabric with a separating device having a single permeable fabric wrapped thereabout such that the tissue web is received directly on the single permeable fabric; transporting the tissue web to a reel with the single permeable fabric; and winding the tissue web onto the reel, the tissue web being received on the reel directly from the single permeable fabric without free draw of the tissue web.
- 31. A method according to claim 30 further comprising directing the tissue web and the single permeable fabric through a web-compressing device, the web-compressing device having a nip formed between the separating device and a roll disposed adjacent thereto and configured to reduce the dry caliper of the web by between about 20% and about 50%, prior to winding the tissue web onto the reel.
- 32. A method according to claim 30 further comprising directing the tissue web and the single permeable fabric through a web-compressing device, the web-compressing device having a nip formed between the separating device and a roll disposed adjacent thereto and configured to reduce the dry caliper of the web to between about 0.15 mm and about 0.4 mm, so as to provide a post-compression density of between about 25 kg/m3 and about 333.3 kg/m3, prior to winding the tissue web onto the reel.
- 33. A method for making a tissue with enhanced tactile quality and facilitating reel-up of the tissue in a dry end of a tissue paper-making machine, said method comprising:finally drying a tissue web, having a basis weight of between about 10 g/m2 and about 50 g/m2, on a through-air drying fabric with a through air dryer, the web having a dry caliper of between about 0.2 mm and about 0.5 mm and, therefore, a density of between about 20 kg/m3 and about 250 kg/M3; separating the tissue web from the through-air drying fabric with a separating device such that the tissue web is received directly on the separating device; directing the tissue web through a web-compressing device having a nip formed between the separating device and a roll disposed adjacent thereto, the roll having a single fabric wrapped thereabout such that the tissue web is received on the single fabric at the nip; transporting the tissue web to a reel with the single fabric; and winding the tissue web on the reel, the tissue web being received on the reel directly from the single fabric without free draw of the tissue web.
- 34. A method according to claim 33 wherein directing the tissue web through a web-compressing device further comprises directing the tissue web through a web-compressing device so as to reduce the dry caliper of the web by between about 20% and about 50% prior to winding the tissue web onto the reel.
- 35. A method according to claim 33 wherein directing the tissue web through a web-compressing device further comprises directing the tissue web through a web-compressing device so as to reduce the dry caliper of the web to between about 0.15 mm and about 0.4 mm, so as to provide a post-compression density of between about 25 kg/m3 and about 333.3 kg/m3, prior to winding the tissue web onto the reel.
US Referenced Citations (23)
Foreign Referenced Citations (3)
Number |
Date |
Country |
1389992 |
Apr 1975 |
GB |
WO 9624718 |
Aug 1996 |
WO |
WO 0144568 |
Jun 2001 |
WO |