CA2050663C - Belt for papermaking machines - Google Patents
Belt for papermaking machines Download PDFInfo
- Publication number
- CA2050663C CA2050663C CA002050663A CA2050663A CA2050663C CA 2050663 C CA2050663 C CA 2050663C CA 002050663 A CA002050663 A CA 002050663A CA 2050663 A CA2050663 A CA 2050663A CA 2050663 C CA2050663 C CA 2050663C
- Authority
- CA
- Canada
- Prior art keywords
- belt
- layer
- textile
- liquid
- fiber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- 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
- D21F3/0209—Wet presses with extended press nip
- D21F3/0218—Shoe presses
- D21F3/0227—Belts or sleeves therefor
Landscapes
- Paper (AREA)
- Artificial Filaments (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)
- Impression-Transfer Materials And Handling Thereof (AREA)
- Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
- Machines For Manufacturing Corrugated Board In Mechanical Paper-Making Processes (AREA)
Abstract
The invention concerns a belt for papermaking machines, in particular for wet presses with extended press nips, said belt evincing a flexible, liquid-impermeable belt layer smooth on its back side and incorporating only in part on its top side a textile so as to form open cavities. To ensure high flexibility and a high cavity volume to remove the water on one hand and on the other hand to improve bonding between textile and belt layer, the textile 5 comprises a support web 6 and affixed thereto a fiber layer 9 mounted on the side which is adjacent to the belt layer 2, the textile 5 being incorporated only by the fiber layer 9 into the belt layer 2 and the support web 6 being outside the belt layer 2.
Description
v Case 5807 20~0~~3 Dr. Eberhard Janssen A BELT FOR PAPERMAKING MACHINES
The invention concerns a belt for papermaking machine, in particular for wet-presses with extended press nips, said belt comprising a flexible, liquid-impermeable layer smooth on its back and receiving only in part on its top side a textile so as to form open cavities.
In wet-presses of papermaking machines, a substantial part of the liquid still in the paper web is forced out between loaded rolls subtending a pressing nip. The paper web is guided through the press nip by a revolving wet felt, the liquid being expelled from the paper web in the press nip into the wet felt and then being transported away.
Recently wet presses with extended press nips, the so-called "shoe presses" have been developed, wherein the paper web is subjected over a longer path, and hence during a longer time, to high compression, whereby it exits the wet press with greater dry-ness. Belts evincing a flexible, liquid-impermea~~~~~t~~ayer and smooth on their bank side are used in particular to guide the paper web and at least one wet felt passes through such an extended press nip. Such belts move by their smooth backside inside the press nip over a hydraulically loaded shoe forcing the belt against an opposite press roll.
The paper web to be dewatered is guided between this press roll and the belt and is accompanied at least on one side by an additional wet felt moving synchronously and transported the pressed-out water.
Such belts when in the press nip undergo high longitudinal and transverse stresses and incur on both sides significant abrasion.
It has been suggested to solve the former problem by wholly incorporating a woven textile into the belt layer (see German Offenlegungsschriften 32 31 039 and 33 18 984 and US patent 4,559,258). Where palled for, a web may be needled into the woven textile (German Offenlegungsschrift 32 31 039). However these belt embodiments have been found unsatisfactory.
In order to improve the water removal from the top side of the belts, that is the side facing the paper web and resting against a synchronous wet felt, the suggestion already has been made to structure the top side. In this respect belts have been developed into the top side of which textiles were incorporated only in part, that is, they exceed in part above the belt layer. In this manner cavities and ducts are created in the parts of the textile exceeding the belt layer that serve in the removal of the water.
Multi-ply weaves have been suggested as these textiles (German patent 32 35 468; European patent 0,098,502; European disclosure 0,138,796; German Gebrauchsmuster 83 19 684.6; European disclosure 0,185,108). The weaves may also be replaced by spiral fabrics (European patent 0,098,502) or warp knit fabrics (European disclosure 0,290,653).
As regards the species of the last cited belts, a problem arises in permanently securing the bonding between the belt layer and the textile absorbing the tensile forces.
Such a belt is subjected to high pressures and fulling stresses with different forces applied at the front and back, especially inside the press nip. If the textile is deeply incorporated into the belt layer, it must be extraordinarily thick in order that, in spite of deeply penetrating the cross-section of the belt layer, it can project so much from it that adequate cavity volume is achieved to evacuate the water. However such a thick textile entails the belt becoming stiff and therefore adapting only poorly to the shape of the shoe and to curvatures when passing over guide rolls. If the textile is incorporated in more shallow manner into the belt layer, it will more easily be torn out.
Accordingly the object of the invention is to so design a belt of the initially cited kind that on one hand it evinces high flexibility and a large cavity volume for water removal while on the other hand it also achieves improved bonding between the textile and the belt layer.
The invention provides a belt for use in papermaking machines, especially in wet presses having an extended press nip, which belt has a flexible, liquid-impervious layer which is smooth at its rear side and in the front side of which a textile product is embedded only partially, forming open hollow spaces, the textile product (5) having a support web (6) and also a fiber layer (9) which is secured to said support web and which is arranged at the side adjacent tc the belt layer (2), characterised in that the textile product (5) is embedded only by the fiber layer (9) in the belt layer (2), and the support web (6) is situated outside of the belt layer (2).
In the invent:icn, the belt manufacture resorts to a textile which in known manner comprises a support web adequate for the tensile forces b:zt additionally comprising a fiber layer .~ffi;ted t~:~ t:: he sup~c;rt web at least on one side, the textile being :i_n~~crporated into the belt layer only by the fiber layer, wuereby the :~uzppor~ web lies entirely outside the belt:..Layer. Thi~a design - 3a -oLiers the advantage ~n the first place that even a ~~~t~~e~~ thin support web, for instance a single-layer weave or kni[~t, Ucabn form a comparatively high cavity volume -- because being entirely outside the belt layer. In commensurate manner the support web little hampers the belt flexibility. Surprisingly it was found that the boncting between the textile and the belt layer is better than in the known solutions in which a support web is partly incorporated into the belt layer, even though the bonding is implemented by the fiber layer alone. Shear strength also is improved.
In addition, the fiber layer is able to absorb some dif-ferential changes in lengths on one hand of the belt layer and on the other of the support web such as might arise from differing materials for these components. Accordingly the particular optimal materials can be used for the belt layer and the support web in a manner substantially independent of their physical properties. As a result this belt offers significantly improved properties rela-tive to all belts of this kind known to-date.
The invention provides that the textile side which is away from the belt layer also bears a fiber layer. As a result additional cushioning of the paper side is achieved. When such fiber layer is suitably designed, even the heretofore obligatory wet felt, synchronously moving with and between the belt and the paper web, can be dropped. Substantial savings are possible there-by.
Appropriately the fiber layers) is (are) needled fiber webs, especially with longitudinally arrayed fibers. Each fiber layer may consist of several needled fiber webs. Single-layer or multi layer weaves, knits or sheets of unwoven filaments or combinations thereof may form the support web, however other textile lengths provided they can absorb tensile forces, are suitable.
Another feature of the invention provides reinforcing filaments being inserted longitudinally and/or transversely into the fiber layer(s). Moreover, the support web may consist of two or more superposed weaves or knits joined to each other by needling the fiber layer(s).
The drawing elucidates the invention by means of an illustrative embodiment shown in longitudinal section.
This drawing shows a belt 1 comprising a belt layer 2 with a top side 3 and a back side 4. The back side 4 is ground smooth. In the application of the invention, namely in the wet press of a papermaking machine with extended press nip, this back side 4 slides past the pressure shoe in the press nip.
A textile 5 is present at the top side 3 of the belt layer 2 and comprises a support web 6 in the form of a double-stratum weave with longitudinal and transverse filaments illustratively denoted by 7 and 8 resp., a fiber layer 9 and 10 being needled into the top and bottom side resp. of said weave. The fiber layer 9, 10 forms the particular outermost layers of the textile 5. The top fiber layer 9 is partly incorporated into the belt layer 2 in such manner that the support web 6 remains completely outside the belt layer 2. In this manner the connection between the support web 6 and the belt layer 2 is implemented solely by the fiber layer 9. Nevertheless an extraordinarily shear-resistant connection between textile 5 and belt layer 2 is achieved thereby. The support web itself 6 absorbs the tensile forces acting on the belt 1.
The lower fiber layer 10 serves as a cushion against a synchronous wet felt pressing against it and in turn bearing the paper web. Provided the fiber layer 10 be suitably designed, the wet felt will not be needed, whereby the paper web can directly rest against the belt 1, that is against the fiber layer 10.
Suitable longitudinal and transverse filaments 7, 8 are all PEK, PEEK, PPS all polyester mixtures, PBT and all conceivable polyamide variations, in particular PA6.6, PA6, PA6.10, PA6.12 and - 5a -PA10 and PAll . Polyams ~f= , polye~~t:er, PPS and PAN may be used for the fiber layer: 9, 10.
Preferably at least one of 1=he fiber layers 9, 10 has fibers that point in 'the direction. of advance of the belt.
_.
The invention concerns a belt for papermaking machine, in particular for wet-presses with extended press nips, said belt comprising a flexible, liquid-impermeable layer smooth on its back and receiving only in part on its top side a textile so as to form open cavities.
In wet-presses of papermaking machines, a substantial part of the liquid still in the paper web is forced out between loaded rolls subtending a pressing nip. The paper web is guided through the press nip by a revolving wet felt, the liquid being expelled from the paper web in the press nip into the wet felt and then being transported away.
Recently wet presses with extended press nips, the so-called "shoe presses" have been developed, wherein the paper web is subjected over a longer path, and hence during a longer time, to high compression, whereby it exits the wet press with greater dry-ness. Belts evincing a flexible, liquid-impermea~~~~~t~~ayer and smooth on their bank side are used in particular to guide the paper web and at least one wet felt passes through such an extended press nip. Such belts move by their smooth backside inside the press nip over a hydraulically loaded shoe forcing the belt against an opposite press roll.
The paper web to be dewatered is guided between this press roll and the belt and is accompanied at least on one side by an additional wet felt moving synchronously and transported the pressed-out water.
Such belts when in the press nip undergo high longitudinal and transverse stresses and incur on both sides significant abrasion.
It has been suggested to solve the former problem by wholly incorporating a woven textile into the belt layer (see German Offenlegungsschriften 32 31 039 and 33 18 984 and US patent 4,559,258). Where palled for, a web may be needled into the woven textile (German Offenlegungsschrift 32 31 039). However these belt embodiments have been found unsatisfactory.
In order to improve the water removal from the top side of the belts, that is the side facing the paper web and resting against a synchronous wet felt, the suggestion already has been made to structure the top side. In this respect belts have been developed into the top side of which textiles were incorporated only in part, that is, they exceed in part above the belt layer. In this manner cavities and ducts are created in the parts of the textile exceeding the belt layer that serve in the removal of the water.
Multi-ply weaves have been suggested as these textiles (German patent 32 35 468; European patent 0,098,502; European disclosure 0,138,796; German Gebrauchsmuster 83 19 684.6; European disclosure 0,185,108). The weaves may also be replaced by spiral fabrics (European patent 0,098,502) or warp knit fabrics (European disclosure 0,290,653).
As regards the species of the last cited belts, a problem arises in permanently securing the bonding between the belt layer and the textile absorbing the tensile forces.
Such a belt is subjected to high pressures and fulling stresses with different forces applied at the front and back, especially inside the press nip. If the textile is deeply incorporated into the belt layer, it must be extraordinarily thick in order that, in spite of deeply penetrating the cross-section of the belt layer, it can project so much from it that adequate cavity volume is achieved to evacuate the water. However such a thick textile entails the belt becoming stiff and therefore adapting only poorly to the shape of the shoe and to curvatures when passing over guide rolls. If the textile is incorporated in more shallow manner into the belt layer, it will more easily be torn out.
Accordingly the object of the invention is to so design a belt of the initially cited kind that on one hand it evinces high flexibility and a large cavity volume for water removal while on the other hand it also achieves improved bonding between the textile and the belt layer.
The invention provides a belt for use in papermaking machines, especially in wet presses having an extended press nip, which belt has a flexible, liquid-impervious layer which is smooth at its rear side and in the front side of which a textile product is embedded only partially, forming open hollow spaces, the textile product (5) having a support web (6) and also a fiber layer (9) which is secured to said support web and which is arranged at the side adjacent tc the belt layer (2), characterised in that the textile product (5) is embedded only by the fiber layer (9) in the belt layer (2), and the support web (6) is situated outside of the belt layer (2).
In the invent:icn, the belt manufacture resorts to a textile which in known manner comprises a support web adequate for the tensile forces b:zt additionally comprising a fiber layer .~ffi;ted t~:~ t:: he sup~c;rt web at least on one side, the textile being :i_n~~crporated into the belt layer only by the fiber layer, wuereby the :~uzppor~ web lies entirely outside the belt:..Layer. Thi~a design - 3a -oLiers the advantage ~n the first place that even a ~~~t~~e~~ thin support web, for instance a single-layer weave or kni[~t, Ucabn form a comparatively high cavity volume -- because being entirely outside the belt layer. In commensurate manner the support web little hampers the belt flexibility. Surprisingly it was found that the boncting between the textile and the belt layer is better than in the known solutions in which a support web is partly incorporated into the belt layer, even though the bonding is implemented by the fiber layer alone. Shear strength also is improved.
In addition, the fiber layer is able to absorb some dif-ferential changes in lengths on one hand of the belt layer and on the other of the support web such as might arise from differing materials for these components. Accordingly the particular optimal materials can be used for the belt layer and the support web in a manner substantially independent of their physical properties. As a result this belt offers significantly improved properties rela-tive to all belts of this kind known to-date.
The invention provides that the textile side which is away from the belt layer also bears a fiber layer. As a result additional cushioning of the paper side is achieved. When such fiber layer is suitably designed, even the heretofore obligatory wet felt, synchronously moving with and between the belt and the paper web, can be dropped. Substantial savings are possible there-by.
Appropriately the fiber layers) is (are) needled fiber webs, especially with longitudinally arrayed fibers. Each fiber layer may consist of several needled fiber webs. Single-layer or multi layer weaves, knits or sheets of unwoven filaments or combinations thereof may form the support web, however other textile lengths provided they can absorb tensile forces, are suitable.
Another feature of the invention provides reinforcing filaments being inserted longitudinally and/or transversely into the fiber layer(s). Moreover, the support web may consist of two or more superposed weaves or knits joined to each other by needling the fiber layer(s).
The drawing elucidates the invention by means of an illustrative embodiment shown in longitudinal section.
This drawing shows a belt 1 comprising a belt layer 2 with a top side 3 and a back side 4. The back side 4 is ground smooth. In the application of the invention, namely in the wet press of a papermaking machine with extended press nip, this back side 4 slides past the pressure shoe in the press nip.
A textile 5 is present at the top side 3 of the belt layer 2 and comprises a support web 6 in the form of a double-stratum weave with longitudinal and transverse filaments illustratively denoted by 7 and 8 resp., a fiber layer 9 and 10 being needled into the top and bottom side resp. of said weave. The fiber layer 9, 10 forms the particular outermost layers of the textile 5. The top fiber layer 9 is partly incorporated into the belt layer 2 in such manner that the support web 6 remains completely outside the belt layer 2. In this manner the connection between the support web 6 and the belt layer 2 is implemented solely by the fiber layer 9. Nevertheless an extraordinarily shear-resistant connection between textile 5 and belt layer 2 is achieved thereby. The support web itself 6 absorbs the tensile forces acting on the belt 1.
The lower fiber layer 10 serves as a cushion against a synchronous wet felt pressing against it and in turn bearing the paper web. Provided the fiber layer 10 be suitably designed, the wet felt will not be needed, whereby the paper web can directly rest against the belt 1, that is against the fiber layer 10.
Suitable longitudinal and transverse filaments 7, 8 are all PEK, PEEK, PPS all polyester mixtures, PBT and all conceivable polyamide variations, in particular PA6.6, PA6, PA6.10, PA6.12 and - 5a -PA10 and PAll . Polyams ~f= , polye~~t:er, PPS and PAN may be used for the fiber layer: 9, 10.
Preferably at least one of 1=he fiber layers 9, 10 has fibers that point in 'the direction. of advance of the belt.
_.
Claims (8)
1. A belt for use in a papermaking machine, said belt comprising (i) a flexible, liquid-impervious layer, said liquid-impervious layer comprising a front side and rear side, and (ii) a textile product layer adjacent to said front side of said liquid-impervious layer; wherein said textile product layer comprises a fiber layer partially embedded in the front side of the liquid-impervious layer and a support web removed from the liquid-impervious layer.
2. A belt according to claim 1, wherein the belt is for a wet press having an extended press nip.
3. A belt according to claims 1 or 2, wherein said textile product layer further comprises a further fiber layer removed from the front side of the liquid-impervious layer.
4. A belt according to any one of claims 1 to 3, wherein at least one of said fiber layers is a needled-on fiber web.
5. A belt according to any one of claims 1 to 4, wherein said support web is a weave, a knit or a sheet of unwoven, superposed filaments or a combination thereof.
6. A belt according to any one of claims 1 to 5, wherein at least one of said fiber layers has fibers pointing in the direction of advance of the belt.
7. A belt according to any one of claims 1 to 6, wherein longitudinal and/or transverse reinforcing filaments are embedded in at least one of the fiber layers.
8. A belt according to any one of claims 1 to 7, wherein the support web consists of two or more superposed weaves connected by the fiber layers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4028085A DE4028085C1 (en) | 1990-09-05 | 1990-09-05 | |
| DEP4028085.3 | 1990-09-05 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2050663A1 CA2050663A1 (en) | 1992-03-06 |
| CA2050663C true CA2050663C (en) | 2004-04-13 |
Family
ID=6413608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002050663A Expired - Fee Related CA2050663C (en) | 1990-09-05 | 1991-09-04 | Belt for papermaking machines |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0473969B1 (en) |
| AT (1) | ATE115663T1 (en) |
| CA (1) | CA2050663C (en) |
| DE (2) | DE4028085C1 (en) |
| DK (1) | DK0473969T3 (en) |
| ES (1) | ES2065588T3 (en) |
| FI (1) | FI93240C (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6027615A (en) * | 1997-05-06 | 2000-02-22 | Albany International Corp. | Belts for compliant calendering |
| DE50013339D1 (en) * | 1999-09-30 | 2006-09-28 | Voith Paper Patent Gmbh | Method and device for dewatering a fibrous web |
| US6645420B1 (en) | 1999-09-30 | 2003-11-11 | Voith Sulzer Papiertechnik Patent Gmbh | Method of forming a semipermeable membrane with intercommunicating pores for a pressing apparatus |
| DE50112624D1 (en) | 2001-04-18 | 2007-07-26 | Stowe Woodward Ag | nip press |
| EP1293601A1 (en) | 2001-09-17 | 2003-03-19 | Stowe Woodward Aktiengesellschaft | Belt for shoe press |
| GB0204308D0 (en) * | 2002-02-23 | 2002-04-10 | Voith Fabrics Heidenheim Gmbh | Papermachine clothing |
| US7011730B2 (en) | 2002-12-30 | 2006-03-14 | Albany International Corp. | Structure for process belt |
| DE102004011665A1 (en) * | 2004-03-10 | 2005-10-06 | Stowe Woodward Ag | Integral shoe press belt |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4271222A (en) * | 1980-02-04 | 1981-06-02 | Albany International Corp. | Papermakers felt and method of manufacture |
| GB2106555B (en) * | 1981-09-15 | 1985-10-02 | Albany Int Corp | Improvements relating to extended nip dewatering presses and to the manufacture of belts for use in such presses |
| NL185678C (en) * | 1981-09-24 | 1990-06-18 | Albany Int Corp | Pressing device for dewatering a fiber web, as well as a method for manufacturing an endless belt therefor. |
| JPS61252389A (en) * | 1985-04-25 | 1986-11-10 | 市川毛織株式会社 | Papermaking press belt |
-
1990
- 1990-09-05 DE DE4028085A patent/DE4028085C1/de not_active Expired - Fee Related
-
1991
- 1991-08-10 AT AT91113448T patent/ATE115663T1/en not_active IP Right Cessation
- 1991-08-10 EP EP91113448A patent/EP0473969B1/en not_active Expired - Lifetime
- 1991-08-10 ES ES91113448T patent/ES2065588T3/en not_active Expired - Lifetime
- 1991-08-10 DK DK91113448.4T patent/DK0473969T3/en active
- 1991-08-10 DE DE59103872T patent/DE59103872D1/en not_active Expired - Fee Related
- 1991-09-02 FI FI914107A patent/FI93240C/en active
- 1991-09-04 CA CA002050663A patent/CA2050663C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| ATE115663T1 (en) | 1994-12-15 |
| DE4028085C1 (en) | 1992-02-27 |
| FI914107A (en) | 1992-03-06 |
| ES2065588T3 (en) | 1995-02-16 |
| FI914107A0 (en) | 1991-09-02 |
| FI93240C (en) | 1995-03-10 |
| CA2050663A1 (en) | 1992-03-06 |
| FI93240B (en) | 1994-11-30 |
| EP0473969B1 (en) | 1994-12-14 |
| DK0473969T3 (en) | 1995-05-08 |
| EP0473969A1 (en) | 1992-03-11 |
| DE59103872D1 (en) | 1995-01-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |