CA2405162C - Soft crepe paper machine and press section thereof - Google Patents
Soft crepe paper machine and press section thereof Download PDFInfo
- Publication number
- CA2405162C CA2405162C CA002405162A CA2405162A CA2405162C CA 2405162 C CA2405162 C CA 2405162C CA 002405162 A CA002405162 A CA 002405162A CA 2405162 A CA2405162 A CA 2405162A CA 2405162 C CA2405162 C CA 2405162C
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- Prior art keywords
- press
- roll
- felt
- web
- suction
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- Expired - Fee Related
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- 238000001035 drying Methods 0.000 claims abstract description 29
- 239000007787 solid Substances 0.000 claims abstract description 26
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 230000006835 compression Effects 0.000 description 11
- 238000007906 compression Methods 0.000 description 11
- 238000003825 pressing Methods 0.000 description 9
- 238000010276 construction Methods 0.000 description 5
- 238000004140 cleaning Methods 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 210000000481 breast Anatomy 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000007605 air drying Methods 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Classifications
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F3/00—Press section of machines for making continuous webs of paper
- D21F3/02—Wet presses
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F3/00—Press section of machines for making continuous webs of paper
- D21F3/02—Wet presses
- D21F3/0281—Wet presses in combination with a dryer roll
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/14—Making cellulose wadding, filter or blotting paper
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G1/00—Calenders; Smoothing apparatus
- D21G1/02—Rolls; Their bearings
- D21G1/0206—Controlled deflection rolls
- D21G1/0213—Controlled deflection rolls with deflection compensation means acting between the roller shell and its supporting member
- D21G1/022—Controlled deflection rolls with deflection compensation means acting between the roller shell and its supporting member the means using fluid pressure
Abstract
A soft crepe paper machine is disclosed which avoids compromise of prior machines on length, capital cost or high bulk, by providing a simplified machine comprising a wet section (1) with a press section having a press (11) with first and second press elements (12, 13), forming a press nip, through which a press felt (14) runs, a suction roll being arranged in the loop of the press felt before the press nip at a distance from the second press element, around which suction roll the press felt runs with a large wrap angle, and a drying cylinder (17) forming said second press element. Said first press element is either a solid press roll (12a), a suction press roll (12b), a variable crown press roll (12c), or a variable crown press roll (12d) the crown curve of which is controllable within at least two zones of the press roll.
Description
Soft crepe paper machine and press section thereof The present invention relates to a machine for manufacturing a web of soft crepe paper, comprising - a wet section, having a former and a press section, which press section comprises - a press including a first press element and a second press element, which press elements define a press nip between them, - a press felt carrying the web and running through said press nip, and - a suction device arranged in the loop of the press felt before said press nip and at a distance from said second press element and having a curved suction zone, the press felt running over said suction zone and the suction device and the press felt being arranged so that the press felt has a large wrap angle around the suction device, and - a drying section including at least a first drying cylinder, which forms said second press element.
The invention also relates to a press section in a machine for manufacturing a web of soft crepe paper, comprising - a press including a first press element and a second press element, which press elements define a press nip between them, the second press element being formed by a drying cylinder in the drying section of the machine, - a press felt carrying the web and running through'said press nip, and - a suction device arranged in the loop of the press felt before said press nip and at a distance from said second press element and having a curved suction zone, the press felt running over said suction zone and the suction device and the press felt being arranged so that the press felt has a large wrap angle around the suction device.
The invention also relates to a press section in a machine for manufacturing a web of soft crepe paper, comprising - a press including a first press element and a second press element, which press elements define a press nip between them, the second press element being formed by a drying cylinder in the drying section of the machine, - a press felt carrying the web and running through'said press nip, and - a suction device arranged in the loop of the press felt before said press nip and at a distance from said second press element and having a curved suction zone, the press felt running over said suction zone and the suction device and the press felt being arranged so that the press felt has a large wrap angle around the suction device.
US 5,230,776 and US 3,691,010 describe conventional machines with two presses, in both of which the drying cylinder acts as a counter roll and the first press has a suction press roll that can be crowned. To avoid running problems, the press felt must be conveyed out in a side loop between the two press nips. The web reaches the first press nip with a dry-solids content of about 10-15 per cent. In a modified second embodiment of the machine in accordance with US 5,230,776, the second press roll is disconnected and the web-carrying forming wire is extended to the first suction press roll while an open belt of wire type is substituted for the press felt to enclose the web between it and the forming wire, creating a sandwich construction that can be provided with airflow-generating means. Suction boxes can be arranged upstream of the sandwich construction in the loop of the forming wire. The known machine can thereby be modified, from one operational embodiment to another that provides a higher dry-solids content, and be adapted to different market needs. Thus, in the second embodiment, which is of a relatively complicated construction, the suction press roll is used in combination with an open belt and not solely with a press felt, and the suction means, located upstream of the suction press roll, are not arranged in a press-felt loop running through the press nip.
US 4,055,461 describes a soft crepe paper machine having a pick-up suction roll and a press section with double press nips against a suction press roll, where the web is compressed in the first press nip before reaching the second press nip against the drying cylinder, which affects the bulk detrimentally.
So-called through-air drying is used to increase the dry-solids content of the web before the drying cylinder.
The increased dry-solids content allows the nip pressure to be reduced substantially in the subsequent press nip, in comparison with a conventional soft crepe paper machine, so that a desired high bulk is obtained.
However, a through-air dryer represents high capital expenditure and requires additional space in the machine line. Furthermore, it has high running costs, as hot air is utilized.
In accordance with another technique for obtaining an increased dry-solids content before the press nip, a suction device is utilized and the pressing takes then place in an extended shoe press nip. A machine constructed in accordance with this technique is described in EP 0 926 296. The press is a shoe press formed by a shoe press roll and the drying cylinder as counter roll. The suction device is shown in the patent specification as a suction roll arranged before the extended shoe press nip at a distance from the drying cylinder. The suction roll enables the dry-solids content of the web to be increased to a high level before the press nip. Such an increased dry-solids content before the press nip is thus advantageous, as it becomes possible thereby to reduce the compression pressure in the press nip so that a substantially increased bulk can be obtained since the web is compressed to a lesser extent. However, a shoe press roll is a relatively complicated construction, entailing high capital expenditure and requiring special operational control.
Machines with similar shoe presses are described in EP 0 851 059 and EP 0 854 229, although, in both cases, a suction roll in the specified position before the shoe press nip is lacking.
It is therefore an object of the present invention to provide a soft crepe paper machine having a simpler press section, which results in reduced capital expenditure and enables a paper web with high bulk to be manufactured in a simpler and more cost effective way than has heretofore been possible, as well as enabling the user of the soft crepe paper machine to choose press elements in accordance with his specific needs.
The machine and press section in accordance with the invention are characterized in that said first press element comprises (a) a solid press roll, (b) a suction press roll, (c) a variable crown press roll, (d) a variable crown press roll, the crown curve of which is controllable within at least two zones of the press roll, or (e) a press roll having at least two of the properties of the press rolls (a) to (d) .
The invention is further described in the following with reference to the drawings.
Figure 1 shows schematically a soft crepe paper machine with a press section in accordance with a first embodiment.
Figure 2 shows schematically a soft crepe paper machine with a press section in accordance with a second embodiment.
Figure 3 shows schematically a soft crepe paper machine with a press section in accordance with a third embodiment.
Figure 3a is a longitudinal sectional view of one of the end portions of a variable crown press roll in the press section in accordance with Figure 3.
Figure 4 shows schematically a soft crepe paper machine with a press section in accordance with a fourth embodiment.
US 4,055,461 describes a soft crepe paper machine having a pick-up suction roll and a press section with double press nips against a suction press roll, where the web is compressed in the first press nip before reaching the second press nip against the drying cylinder, which affects the bulk detrimentally.
So-called through-air drying is used to increase the dry-solids content of the web before the drying cylinder.
The increased dry-solids content allows the nip pressure to be reduced substantially in the subsequent press nip, in comparison with a conventional soft crepe paper machine, so that a desired high bulk is obtained.
However, a through-air dryer represents high capital expenditure and requires additional space in the machine line. Furthermore, it has high running costs, as hot air is utilized.
In accordance with another technique for obtaining an increased dry-solids content before the press nip, a suction device is utilized and the pressing takes then place in an extended shoe press nip. A machine constructed in accordance with this technique is described in EP 0 926 296. The press is a shoe press formed by a shoe press roll and the drying cylinder as counter roll. The suction device is shown in the patent specification as a suction roll arranged before the extended shoe press nip at a distance from the drying cylinder. The suction roll enables the dry-solids content of the web to be increased to a high level before the press nip. Such an increased dry-solids content before the press nip is thus advantageous, as it becomes possible thereby to reduce the compression pressure in the press nip so that a substantially increased bulk can be obtained since the web is compressed to a lesser extent. However, a shoe press roll is a relatively complicated construction, entailing high capital expenditure and requiring special operational control.
Machines with similar shoe presses are described in EP 0 851 059 and EP 0 854 229, although, in both cases, a suction roll in the specified position before the shoe press nip is lacking.
It is therefore an object of the present invention to provide a soft crepe paper machine having a simpler press section, which results in reduced capital expenditure and enables a paper web with high bulk to be manufactured in a simpler and more cost effective way than has heretofore been possible, as well as enabling the user of the soft crepe paper machine to choose press elements in accordance with his specific needs.
The machine and press section in accordance with the invention are characterized in that said first press element comprises (a) a solid press roll, (b) a suction press roll, (c) a variable crown press roll, (d) a variable crown press roll, the crown curve of which is controllable within at least two zones of the press roll, or (e) a press roll having at least two of the properties of the press rolls (a) to (d) .
The invention is further described in the following with reference to the drawings.
Figure 1 shows schematically a soft crepe paper machine with a press section in accordance with a first embodiment.
Figure 2 shows schematically a soft crepe paper machine with a press section in accordance with a second embodiment.
Figure 3 shows schematically a soft crepe paper machine with a press section in accordance with a third embodiment.
Figure 3a is a longitudinal sectional view of one of the end portions of a variable crown press roll in the press section in accordance with Figure 3.
Figure 4 shows schematically a soft crepe paper machine with a press section in accordance with a fourth embodiment.
5 Figure 4a is a longitudinal sectional view of a zone-controllable, variable crown press roll in the press section in accordance with Figure 4.
Figures 1-4 show schematically parts of paper machines for manufacturing soft crepe paper such as tissue and other creped hygiene paper products. Each paper machine comprises a wet section 1 and a drying section 2. The wet section 1 comprises a former and a press section. The former has a headbox 4, an inner, carrying forming clothing 5, an outer, covering forming clothing 6, a forming roll 7 and a breast roll 8. The forming roll 7 and the breast roll 8 are arranged in proximity to each other so that the two forming clothings 5, 6 run together on the forming roll 7 whilst defining a wedge-shaped gap between them before they run together, the headbox. 4 delivering a single- or multi-layer jet of stock into said gap to form a paper web 9 by way of the stock being dewatered. The two forming clothings 5, 6 run together over the forming roll 7 and then in individual loops over a plurality of rolls 10 arranged to move, guide, align and stretch the forming clothings 5, 6.
The press section comprises a roll press 11, consisting of a first press roll 12 and a second press roll 13, which press rolls 12, 13 define a press nip between them.
It is preferable for the press section to have only one press, i.e. roll press, as shown in the drawings, so that no additional press nip is formed against the second press roll 13 or against the first press roll 12 or defined by any two other press elements. Further, the press section has a press felt 14, running through the press nip and in a loop around a plurality of rolls 15, arranged to move, guide, align and stretch the press felt 14. Devices (not shown) for cleaning the press felt 14 are located after the press nip. In the loop of the press felt 14, there is a suction device 16, which, in the embodiment shown, consists of a suction roll that is arranged just before the press nip and from which the press felt 14 carries the web 9 so that the side of the web 9 facing away from the felt is free from contact with any structural element before the press nip. The suction device 16, which has a curved suction zone 3, is so arranged in relation to the nearest upstream guide roll and the downstream press roll 12 that the press felt 14 has a high wrap around the suction device 16, i.e. the press felt 14 and the paper web 9 carried by the same 15 change direction at a large angle over the suction zone 3. The wrap angle should be at least 100 , preferably at least 110 . In experiments performed with a suction roll, the wrap angle has been about 140 . The suction zone 3 encloses a sector angle corresponding to said wrap angle and extends within the same. The large wrap angle contributes to increased dewatering. The suction device 16 is arranged to provide the paper web 9 with a dry-solids content of at least 15 per cent, preferably at least 20 per cent and most preferably at least 25 per cent.
The drying section 2 comprises a crowned drying cylinder 17 having a relatively large diameter and a polished envelope surface. The drying cylinder 17, which preferably consists of a Yankee cylinder, is covered by a hood 18, in which hot air is blown at high speed against the paper web 9. The paper web is creped away from the drying cylinder 17 with the aid of a crepe doctor 19 to obtain desired creping, whereupon the finished creped paper web 9'is reeled onto a reel (not shown). The drying cylinder 17 also forms said second press roll 13 in the roll press 11 of the drying section 2. Said suction roll 16 is arranged at a distance from the drying cylinder 17 so that no press nip is formed between them and so that the web 9 does not come into contact with the envelope surface of the drying cylinder 17 until it reaches the press nip or immediately before.
In the paper machines in accordance with Figures 1 and 2, the inner carrying forming clothing 5 consists of a forming felt, the loop of which is extended to the press section 2 so that it also acts as said press felt 14.
In the paper machines in accordance with Figures 3 and 4, the inner carrying forming clothing 5 consists of a forming wire, the loop of which encounters the loop of the press felt 14 in a transfer zone 20 for transferring the web 9 to the press felt 14, a suction shoe 21 being arranged within said transfer zone 20 in the loop of the press felt 14.
In the paper machine in accordance with Figure 1, the first press roll 12 of the roll press 11 consists of a press roll 12a with a solid shell 22 that can be smooth, grooved or blind-drilled. The press roll 12a can be straight depending on the crown of the drying cylinder 13, amongst other things, but is preferably crowned so that it has a crown curve corresponding to a certain compression pressure to obtain profiles for compression-pressure and dry-solids content that are as uniform as possible after pressing without zones with higher moisture occurring in the web after the press nip.
In the paper machine in accordance with Figure 2, the first press roll 12 of the roll press 11 consists of a suction press roll 12b that can be straight depending on the crown of the drying cylinder, amongst other things, but which is preferably crowned so that it has a crown curve corresponding to a certain compression pressure to obtain profiles for compression-pressure and dry-solids content that are as uniform as possible without zones with higher moisture occurring in the web after the press nip. A special advantage of the suction press roll 12b is that it also has a cleaning effect on the press felt 14 so that special cleaning means arranged after the press nip can be completely or partly reduced and the frequency of felt replacements can be diminished.
In the paper machine in accordance with Figure 3, the first press roll 12 of the roll press 11 consists of a variable crown press roll 12c, the shell of which can be smooth, grooved or blind-drilled. The crown curve of the press roll 12c can be changed during operation to be adapted to a pre-determined compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content are obtained without zones with higher moisture occurring in the web after the press nip.
If the machine is to manufacture a soft crepe paper of a different desired grade with respect to bulk and strength, the crown curve is changed to correspond to a new compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content for the new setting are obtained without zones with higher moisture occurring in the web after the press nip.
Figure 3a shows schematically a longitudinal section of one of the end portions of the variable crown press roll 12c, the shell 22 of which surrounds an upper pressure chamber 23, connected to a pressure source (not shown).
The pressure chamber 23 extends between the end walls 24 of the press roll, the ends of the shell 22 being rigidly attached to said end walls. Changing the pressure in the pressure chamber 23 produces a corresponding change of the crown curve within the press nip. The shell 22 also surrounds a lower pressure chamber 25 having a pre-determined lower pressure than the upper pressure chamber 23. The pressure chambers are separated by opposite, axial sliding sealings 26.
In the paper machine in accordance with Figure 4, the first press roll 12 of the roll press 11 consists of a zone-controllable, variable crown press roll 12d, the shell 22 of which can be smooth, grooved or blind-drilled. The crown curve of the press roll 12d can be changed during operation to be adapted to a pre-determined compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content are obtained without zones with higher moisture occurring in the web after the press nip. If the machine is to manufacture a soft crepe paper of a different desired grade with respect to bulk and strength, the crown curve is changed to correspond to a new compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content for the new setting are obtained without zones with higher moisture occurring in the web after the press nip. In this embodiment, the crown curve can additionally be influenced zone by zone so as thereby to adjust the compression-pressure profile within the corresponding parts so that the same becomes even more uniform and straight than is possible with a variable crown press roll that is not zone-controllable to obtain a dry-solids content profile after the press nip that is correspondingly more uniform and straight. Figure 4a shows schematically a longitudinal section of the zone-controllable, variable crown press roll 12d, which has an axial row of pressing members 27 equidistantly arranged inside the shell 22 and opposite to the press nip. With respect to their pressing influence on the shell 22, the pressing members 27 are divided into two outer groups 28, 29 and an inner or intermediate group 30 between them, the groups 28, 29, 30 of pressing members 27 being actuated independently of each other via separate ducts 31, 32 and 33, respectively, provided with valves. Each group of pressing members 27 actuates its corresponding axial zone of the shell and, consequently, the crown curve.
The drying cylinder 13 is crowned in at least the embodiments in accordance with Figures 1-3. A special advantage of the embodiment in accordance with Figure 4 is that the drying cylinder 13 does not need to be 10 crowned.
In all cases, the press roll 12 is driven and its shell 22 comprises an outer layer of a rubber material or a rubber-like material. The thickness and softness of the rubber layer is chosen as needed. A certain compression of the rubber layer occurs in the press nip so that it is extended somewhat in the direction of movement of the web. It should thus be understood that the thickness and softness of said parameters determine the length of the extended press nip at a given compression pressure. The linear load, which corresponds to the impulse of pressure, is a function of compression pressure, pressing time and machine speed. If the compression pressure is increased, the pressing time will increase as well, since the rubber layer of the shell is compressed further so that the press nip becomes longer.
Each one of the described roll presses is of a substantially simpler construction than the known shoe press in accordance with EP 0 926 296, which results in reduced capital expenditure and enables the manufacture of a soft crepe paper with a bulk substantially as high as with the said known shoe press, but in a simpler and more cost effective way. Furthermore, the user has the advantageous opportunity of choosing, out of the alternatives, that press roll which is most suited to the specific needs of the user as regards whether the same grade is to be produced for a longer period of time (suitably press roll 12a or 12b) or different grades are to be produced alternatingly in smaller series (suitably press roll 12c or 12d).
In a further embodiment (not shown) the first press element is a press roll having at least two of the properties of the four press rolls 12a to 12d described above, such as, for instance, a variable crown suction press roll.
Figures 1-4 show schematically parts of paper machines for manufacturing soft crepe paper such as tissue and other creped hygiene paper products. Each paper machine comprises a wet section 1 and a drying section 2. The wet section 1 comprises a former and a press section. The former has a headbox 4, an inner, carrying forming clothing 5, an outer, covering forming clothing 6, a forming roll 7 and a breast roll 8. The forming roll 7 and the breast roll 8 are arranged in proximity to each other so that the two forming clothings 5, 6 run together on the forming roll 7 whilst defining a wedge-shaped gap between them before they run together, the headbox. 4 delivering a single- or multi-layer jet of stock into said gap to form a paper web 9 by way of the stock being dewatered. The two forming clothings 5, 6 run together over the forming roll 7 and then in individual loops over a plurality of rolls 10 arranged to move, guide, align and stretch the forming clothings 5, 6.
The press section comprises a roll press 11, consisting of a first press roll 12 and a second press roll 13, which press rolls 12, 13 define a press nip between them.
It is preferable for the press section to have only one press, i.e. roll press, as shown in the drawings, so that no additional press nip is formed against the second press roll 13 or against the first press roll 12 or defined by any two other press elements. Further, the press section has a press felt 14, running through the press nip and in a loop around a plurality of rolls 15, arranged to move, guide, align and stretch the press felt 14. Devices (not shown) for cleaning the press felt 14 are located after the press nip. In the loop of the press felt 14, there is a suction device 16, which, in the embodiment shown, consists of a suction roll that is arranged just before the press nip and from which the press felt 14 carries the web 9 so that the side of the web 9 facing away from the felt is free from contact with any structural element before the press nip. The suction device 16, which has a curved suction zone 3, is so arranged in relation to the nearest upstream guide roll and the downstream press roll 12 that the press felt 14 has a high wrap around the suction device 16, i.e. the press felt 14 and the paper web 9 carried by the same 15 change direction at a large angle over the suction zone 3. The wrap angle should be at least 100 , preferably at least 110 . In experiments performed with a suction roll, the wrap angle has been about 140 . The suction zone 3 encloses a sector angle corresponding to said wrap angle and extends within the same. The large wrap angle contributes to increased dewatering. The suction device 16 is arranged to provide the paper web 9 with a dry-solids content of at least 15 per cent, preferably at least 20 per cent and most preferably at least 25 per cent.
The drying section 2 comprises a crowned drying cylinder 17 having a relatively large diameter and a polished envelope surface. The drying cylinder 17, which preferably consists of a Yankee cylinder, is covered by a hood 18, in which hot air is blown at high speed against the paper web 9. The paper web is creped away from the drying cylinder 17 with the aid of a crepe doctor 19 to obtain desired creping, whereupon the finished creped paper web 9'is reeled onto a reel (not shown). The drying cylinder 17 also forms said second press roll 13 in the roll press 11 of the drying section 2. Said suction roll 16 is arranged at a distance from the drying cylinder 17 so that no press nip is formed between them and so that the web 9 does not come into contact with the envelope surface of the drying cylinder 17 until it reaches the press nip or immediately before.
In the paper machines in accordance with Figures 1 and 2, the inner carrying forming clothing 5 consists of a forming felt, the loop of which is extended to the press section 2 so that it also acts as said press felt 14.
In the paper machines in accordance with Figures 3 and 4, the inner carrying forming clothing 5 consists of a forming wire, the loop of which encounters the loop of the press felt 14 in a transfer zone 20 for transferring the web 9 to the press felt 14, a suction shoe 21 being arranged within said transfer zone 20 in the loop of the press felt 14.
In the paper machine in accordance with Figure 1, the first press roll 12 of the roll press 11 consists of a press roll 12a with a solid shell 22 that can be smooth, grooved or blind-drilled. The press roll 12a can be straight depending on the crown of the drying cylinder 13, amongst other things, but is preferably crowned so that it has a crown curve corresponding to a certain compression pressure to obtain profiles for compression-pressure and dry-solids content that are as uniform as possible after pressing without zones with higher moisture occurring in the web after the press nip.
In the paper machine in accordance with Figure 2, the first press roll 12 of the roll press 11 consists of a suction press roll 12b that can be straight depending on the crown of the drying cylinder, amongst other things, but which is preferably crowned so that it has a crown curve corresponding to a certain compression pressure to obtain profiles for compression-pressure and dry-solids content that are as uniform as possible without zones with higher moisture occurring in the web after the press nip. A special advantage of the suction press roll 12b is that it also has a cleaning effect on the press felt 14 so that special cleaning means arranged after the press nip can be completely or partly reduced and the frequency of felt replacements can be diminished.
In the paper machine in accordance with Figure 3, the first press roll 12 of the roll press 11 consists of a variable crown press roll 12c, the shell of which can be smooth, grooved or blind-drilled. The crown curve of the press roll 12c can be changed during operation to be adapted to a pre-determined compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content are obtained without zones with higher moisture occurring in the web after the press nip.
If the machine is to manufacture a soft crepe paper of a different desired grade with respect to bulk and strength, the crown curve is changed to correspond to a new compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content for the new setting are obtained without zones with higher moisture occurring in the web after the press nip.
Figure 3a shows schematically a longitudinal section of one of the end portions of the variable crown press roll 12c, the shell 22 of which surrounds an upper pressure chamber 23, connected to a pressure source (not shown).
The pressure chamber 23 extends between the end walls 24 of the press roll, the ends of the shell 22 being rigidly attached to said end walls. Changing the pressure in the pressure chamber 23 produces a corresponding change of the crown curve within the press nip. The shell 22 also surrounds a lower pressure chamber 25 having a pre-determined lower pressure than the upper pressure chamber 23. The pressure chambers are separated by opposite, axial sliding sealings 26.
In the paper machine in accordance with Figure 4, the first press roll 12 of the roll press 11 consists of a zone-controllable, variable crown press roll 12d, the shell 22 of which can be smooth, grooved or blind-drilled. The crown curve of the press roll 12d can be changed during operation to be adapted to a pre-determined compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content are obtained without zones with higher moisture occurring in the web after the press nip. If the machine is to manufacture a soft crepe paper of a different desired grade with respect to bulk and strength, the crown curve is changed to correspond to a new compression pressure so that as uniform as possible profiles for compression-pressure and dry-solids content for the new setting are obtained without zones with higher moisture occurring in the web after the press nip. In this embodiment, the crown curve can additionally be influenced zone by zone so as thereby to adjust the compression-pressure profile within the corresponding parts so that the same becomes even more uniform and straight than is possible with a variable crown press roll that is not zone-controllable to obtain a dry-solids content profile after the press nip that is correspondingly more uniform and straight. Figure 4a shows schematically a longitudinal section of the zone-controllable, variable crown press roll 12d, which has an axial row of pressing members 27 equidistantly arranged inside the shell 22 and opposite to the press nip. With respect to their pressing influence on the shell 22, the pressing members 27 are divided into two outer groups 28, 29 and an inner or intermediate group 30 between them, the groups 28, 29, 30 of pressing members 27 being actuated independently of each other via separate ducts 31, 32 and 33, respectively, provided with valves. Each group of pressing members 27 actuates its corresponding axial zone of the shell and, consequently, the crown curve.
The drying cylinder 13 is crowned in at least the embodiments in accordance with Figures 1-3. A special advantage of the embodiment in accordance with Figure 4 is that the drying cylinder 13 does not need to be 10 crowned.
In all cases, the press roll 12 is driven and its shell 22 comprises an outer layer of a rubber material or a rubber-like material. The thickness and softness of the rubber layer is chosen as needed. A certain compression of the rubber layer occurs in the press nip so that it is extended somewhat in the direction of movement of the web. It should thus be understood that the thickness and softness of said parameters determine the length of the extended press nip at a given compression pressure. The linear load, which corresponds to the impulse of pressure, is a function of compression pressure, pressing time and machine speed. If the compression pressure is increased, the pressing time will increase as well, since the rubber layer of the shell is compressed further so that the press nip becomes longer.
Each one of the described roll presses is of a substantially simpler construction than the known shoe press in accordance with EP 0 926 296, which results in reduced capital expenditure and enables the manufacture of a soft crepe paper with a bulk substantially as high as with the said known shoe press, but in a simpler and more cost effective way. Furthermore, the user has the advantageous opportunity of choosing, out of the alternatives, that press roll which is most suited to the specific needs of the user as regards whether the same grade is to be produced for a longer period of time (suitably press roll 12a or 12b) or different grades are to be produced alternatingly in smaller series (suitably press roll 12c or 12d).
In a further embodiment (not shown) the first press element is a press roll having at least two of the properties of the four press rolls 12a to 12d described above, such as, for instance, a variable crown suction press roll.
Claims (13)
1. A machine for manufacturing a web of soft crepe paper, comprising a wet section, having a former and a press section, which press section comprises a press including a first press element and a second press element, which press elements define a press nip between them, a press felt carrying the web and running through said press nip, and a suction device arranged in the loop of the press felt before said press nip and at a distance from said second press element and having a curved suction zone, the press felt running over said suction zone and the suction device and the press felt being arranged so that the press felt has a large wrap angle around the suction device of at least 100°, and a drying section including at least a first drying cylinder, which forms said second press element, wherein the press section is structured and arranged such that from the suction device to the press nip, a side of the web facing away from the felt is free from contact with any structural element until said side of the web contacts the drying cylinder in the press nip, wherein said first press element comprises one of a) a solid press roll, b) a suction press roll, c) a variable crown press roll, or d) a variable crown press roll, the crown curve of which is controllable within at least two zones of the press roll.
2. A machine as claimed in claim 1, wherein the press felt is arranged to wrap the suction device with a wrap angle of at least 110°.
3. A machine as claimed in either one of claims 1 and 2, wherein the suction device is arranged to give the web a dry-solids content of at least 15 per cent.
4. A machine as claimed in any one of claims 1 to 3, with a solid press roll or a variable crown press roll wherein the solid press roll or the variable crown press roll have smooth, grooved or blind-drilled shells.
5. A machine as claimed in any one of claims 1 to 3, with a zone-controllable variable crown press roll wherein the zone-controllable, variable crown press roll comprises a plurality of press members, divided into two outer groups and at least one inner group between the two outer groups, the groups of press members being able to be actuated independently of each other to form a corresponding number of zones of the shell that control their respective parts of the crown curve for corresponding adjustment of the compression-pressure profile.
6. A machine as claimed in any one of claims 1 to 5, wherein the suction device consists of a suction roll.
7. A machine as claimed in any one of claims 1 to 6, in which the former has an inner web-carrying forming clothing, wherein the forming clothing is a forming felt arranged to run in a loop up to and through the roll press to constitute said press felt as well.
8. A machine as claimed in any one of claims 1 to 6, in which the former has an inner web-carrying forming clothing, wherein the forming clothing is arranged to run in a loop that encounters the loop of said press felt in a transfer zone for transferring the web to the press felt.
9. A press section is a machine for manufacturing a web of soft crepe paper, comprising a press including a first press element and a second press element, which press elements define a press nip between them, the second press element being formed by a drying cylinder in the drying section of the machine, a press felt carrying the web and running through said press nip, and a suction device arranged in the loop of the press felt before said press nip and at a distance from said second press element and having a curved suction zone, the press felt running over said suction zone and the suction device and the press felt being arranged so that the press felt has a wrap angle around the suction device of at least 100°, wherein the press section is structured and arranged such that from the suction device to the press nip, a side of the web facing away from the felt is free from contact with any structural element until said side of the web contacts the drying cylinder in the press nip, wherein said first press element comprises one of a) a solid press roll, b) a suction press roll, c) a variable crown press roll, or d) a variable crown press roll, the crown curve of which is controllable within at least two zones of the press roll.
10. A press section as claimed in claim 9, wherein the press felt is arranged to wrap the suction device with a wrap angle of at least 110°.
11. A press section as claimed in either one of claims 9 and 10, wherein the suction device is arranged to provide a dry-solids content for the web of at least 15 per cent.
12. A press section as claimed in any one of claims 9 to 11, with a solid press roll or a variable crown press roll wherein the solid press roll or the variable crown press roll have smooth, grooved or blind-drilled shells.
13. A press section as claimed in any one of claims 9 to 11, with a zone-controllable variable crown press roll wherein the zone-controllable, variable crown press roll comprises a plurality of press members, divided into two outer groups and at least one inner group between the two outer groups, the groups of press members being able to be actuated independently of each other to form a corresponding number of zones of the shell that control their respective parts of the crown curve for corresponding adjustment of the compression-pressure profile.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP00110561A EP1156153B1 (en) | 2000-05-18 | 2000-05-18 | Soft crepe paper machine and press section thereof |
| EP00110561.8 | 2000-05-18 | ||
| US21211900P | 2000-06-16 | 2000-06-16 | |
| US60/212,119 | 2000-06-16 | ||
| PCT/SE2001/001027 WO2001088259A1 (en) | 2000-05-18 | 2001-05-11 | Soft crepe paper machine and press section thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2405162A1 CA2405162A1 (en) | 2001-11-22 |
| CA2405162C true CA2405162C (en) | 2008-12-30 |
Family
ID=26070954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002405162A Expired - Fee Related CA2405162C (en) | 2000-05-18 | 2001-05-11 | Soft crepe paper machine and press section thereof |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US6998022B2 (en) |
| JP (1) | JP2003533609A (en) |
| KR (1) | KR20030007562A (en) |
| AU (1) | AU2001260881A1 (en) |
| BR (1) | BR0111357A (en) |
| CA (1) | CA2405162C (en) |
| WO (1) | WO2001088259A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE352666T1 (en) * | 2000-05-18 | 2007-02-15 | Metso Paper Karlstad Ab | SOFT CREPE PAPER MACHINE AND PRESS SECTION THEREOF |
| JP2003533609A (en) * | 2000-05-18 | 2003-11-11 | メッツォ ペーパー カルルスタッド アクチボラグ | Soft crepe paper machine and press section of the machine |
| DE10129613A1 (en) * | 2001-06-20 | 2003-01-02 | Voith Paper Patent Gmbh | Method and device for producing a fibrous web provided with a three-dimensional surface structure |
| US7789995B2 (en) | 2002-10-07 | 2010-09-07 | Georgia-Pacific Consumer Products, LP | Fabric crepe/draw process for producing absorbent sheet |
| US8394236B2 (en) | 2002-10-07 | 2013-03-12 | Georgia-Pacific Consumer Products Lp | Absorbent sheet of cellulosic fibers |
| US7588660B2 (en) * | 2002-10-07 | 2009-09-15 | Georgia-Pacific Consumer Products Lp | Wet-pressed tissue and towel products with elevated CD stretch and low tensile ratios made with a high solids fabric crepe process |
| WO2004033793A2 (en) * | 2002-10-07 | 2004-04-22 | Fort James Corporation | Fabric crepe process for making absorbent sheet |
| US7662257B2 (en) * | 2005-04-21 | 2010-02-16 | Georgia-Pacific Consumer Products Llc | Multi-ply paper towel with absorbent core |
| US7442278B2 (en) | 2002-10-07 | 2008-10-28 | Georgia-Pacific Consumer Products Lp | Fabric crepe and in fabric drying process for producing absorbent sheet |
| US7585389B2 (en) * | 2005-06-24 | 2009-09-08 | Georgia-Pacific Consumer Products Lp | Method of making fabric-creped sheet for dispensers |
| US7494563B2 (en) | 2002-10-07 | 2009-02-24 | Georgia-Pacific Consumer Products Lp | Fabric creped absorbent sheet with variable local basis weight |
| EP1437443A1 (en) * | 2003-01-07 | 2004-07-14 | Park, Sa-Ryong | Paper manufacturing machine |
| US8293072B2 (en) | 2009-01-28 | 2012-10-23 | Georgia-Pacific Consumer Products Lp | Belt-creped, variable local basis weight absorbent sheet prepared with perforated polymeric belt |
| SE529130C2 (en) * | 2004-05-26 | 2007-05-08 | Metso Paper Karlstad Ab | Paper machine for manufacturing fiber web of paper, comprises clothing that exhibits three-dimensional structure for structuring fiber web |
| SE0502801L (en) * | 2005-12-19 | 2007-06-20 | Metso Paper Karlstad Ab | Apparatus and method for increasing the productivity of a paper machine or reducing its dimensions |
| US8540846B2 (en) | 2009-01-28 | 2013-09-24 | Georgia-Pacific Consumer Products Lp | Belt-creped, variable local basis weight multi-ply sheet with cellulose microfiber prepared with perforated polymeric belt |
| CA2735867C (en) | 2008-09-16 | 2017-12-05 | Dixie Consumer Products Llc | Food wrap basesheet with regenerated cellulose microfiber |
| DE102010017648A1 (en) * | 2010-06-29 | 2011-12-29 | Papierwerke Lenk Ag | Process for producing one-sided smooth crepe paper |
| MX368420B (en) * | 2013-09-20 | 2019-10-01 | Stowe Woodward Licensco Llc | Soft rubber roll cover with wide grooves. |
| SE542214C2 (en) | 2018-10-12 | 2020-03-10 | Valmet Oy | A tissue paper making machine and a method of operating a tissue paper making machine |
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| JP2003533609A (en) * | 2000-05-18 | 2003-11-11 | メッツォ ペーパー カルルスタッド アクチボラグ | Soft crepe paper machine and press section of the machine |
| DE10032251A1 (en) * | 2000-07-03 | 2002-01-17 | Voith Paper Patent Gmbh | Water extraction station for a web of tissue/toilet paper has a shoe press unit at the drying cylinder with an extended press gap and a suction unit within an overpressure hood at the carrier belt |
| DE10129613A1 (en) * | 2001-06-20 | 2003-01-02 | Voith Paper Patent Gmbh | Method and device for producing a fibrous web provided with a three-dimensional surface structure |
| US7150110B2 (en) * | 2002-01-24 | 2006-12-19 | Voith Paper Patent Gmbh | Method and an apparatus for manufacturing a fiber web provided with a three-dimensional surface structure |
-
2001
- 2001-05-11 JP JP2001584636A patent/JP2003533609A/en active Pending
- 2001-05-11 BR BR0111357-7A patent/BR0111357A/en not_active Application Discontinuation
- 2001-05-11 CA CA002405162A patent/CA2405162C/en not_active Expired - Fee Related
- 2001-05-11 KR KR1020027014616A patent/KR20030007562A/en not_active Application Discontinuation
- 2001-05-11 WO PCT/SE2001/001027 patent/WO2001088259A1/en active Application Filing
- 2001-05-11 AU AU2001260881A patent/AU2001260881A1/en not_active Abandoned
-
2002
- 2002-11-18 US US10/299,106 patent/US6998022B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| BR0111357A (en) | 2003-04-29 |
| WO2001088259A1 (en) | 2001-11-22 |
| US20030121626A1 (en) | 2003-07-03 |
| CA2405162A1 (en) | 2001-11-22 |
| KR20030007562A (en) | 2003-01-23 |
| AU2001260881A1 (en) | 2001-11-26 |
| US6998022B2 (en) | 2006-02-14 |
| JP2003533609A (en) | 2003-11-11 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |