Claims
- 1. A closed press section in a paper machine, comprising
- a compact combination of press rolls defining press nips with each other, one of said press rolls being a center roll having a smooth cylindrical mantle,
- a plurality of fabrics supporting a web, one of said fabrics comprising a transfer band defining a closed loop around said center roll, said transfer band having an outer face upon which the web is transferred,
- a first central press nip being defined between said center roll, and a first one of said press rolls,
- a last central press nip in the running direction of the web being defined between said center roll and a second one of said press rolls,
- a first fabric, which is also a pick-up fabric which picks up the web from a form section passing through said first press nip and said last press nip, said first fabric having an outer face passing around said center roll,
- the web being continuously carried between said outer face of said first fabric and said outer face of said transfer band through said first press nip and around said center roll to said last press nip, and the web being detached from said first fabric after said last press nip,
- said transfer band defining a closed draw located after said last press nip in said compact combination of rolls, the web being constantly supported in said closed draw,
- said transfer band comprising a fabric which substantially does not receive water such that said transfer band does not rewet the web, said outer face of said transfer band fabric having web-adhesion properties such that, after said last press nip, the web follows the transfer band fabric in a straight run and is transferred in a transfer zone as a fully closed draw onto a drying wire or onto an equivalent fabric that carries the web further into a drying section following said press section, and
- conditioning means for conditioning said transfer band loop, said conditioning means structured and arranged to maintain an adequate operation of said transfer band fabric.
- 2. The press section of claim 1, further comprising
- a suction roll located after said center roll in the running direction of the web, and
- deflecting means located in said straight run in proximity to said suction roll, the web being deflected by said deflecting means in conjunction with said suction roll and being detached from said transfer band fabric in said transfer zone in proximity to said suction roll.
- 3. The press section of claim 1, further comprising an intermediate frame, said center roll being mounted on said intermediate frame by means of fixed bearing supports, said intermediate frame being cantilevered and provided with detachable intermediate pieces for quick replacement of said transfer band loop.
- 4. The press section of claim 1, wherein said transfer band fabric is a substantially impermeable fabric structure, the press section further comprising cleaning means for cleaning a face of said center roll and collecting means for collecting of water and impurities, said cleaning means and said collecting means located on a sector of said center roll free from said transfer band fabric.
- 5. The press section of claim 1, wherein the web is transferred from the face of said transfer band fabric onto the drying wire or equivalent in a transfer zone as a closed draw so that, in said transfer zone, the angle of change in the direction of the web is less than about 60.degree..
- 6. The press section of claim 5, wherein said transfer suction roll is arranged inside a loop of said drying wire and defines said transfer zone such that said transfer zone has a magnitude from about 5.degree. to about 20.degree., the press section further comprising a heater located immediately before said transfer zone by whose means the detaching of the web from said outer face of said transfer band fabric and the transfer of the web as a closed draw onto said drying wire or onto said equivalent transfer fabric are promoted.
- 7. The press section of claim 1, wherein said conditioning means comprise
- a cleaning and/or safety nip defined between a pair of rolls located after said transfer zone and in connection with said transfer band loop, a first one of said pair of rolls in the direction of running of said transfer band fabric being located inside said transfer band loop, and the other one of said pair of rolls being located outside said transfer band loop, and
- jet and/or doctor means located on a sector of said other of said pair of rolls, said jet and/or doctor means being structured and arranged such that a face of said other roll is kept clean and any web which may run over said face of said other roll to broke, is separated from said face of said other roll.
- 8. The press section of claim 7, further comprising an additional heating device arranged in connection with said transfer band loop, said additional heating device structured and arranged to improve cleaning of said transfer band loop and dewatering of the web in the nips through which said transfer band fabric runs.
- 9. The press section of claim 1, wherein another of said press rolls defines a second nip with said center roll, said another press roll being mounted on intermediate frame parts which are attached to a front frame part of said press section by means of horizontal articulated joints, and said press roll which defines said last press nip with said center roll being mounted on other intermediate frame parts which are attached to a rear frame part of said press section by means of horizontal articulated joints, said intermediate frame parts being openable by means of actuators so that a space between said front frame part and said rear frame part is open or quickly openable at a top of said press section, wherein press rolls in said compact combination of rolls placed in the area of said space can be replaced by lifting them substantially straight upwards by means of a crane mounted on a ceiling.
- 10. The press section of claim 2, wherein said deflecting means comprise a guide shoe or a guide roll located immediately before said transfer zone by whose means the detaching of the web from said outer face of said transfer band fabric and the transfer of the web as a closed draw onto said drying wire or onto said equivalent transfer fabric are promoted.
- 11. The press section of claim 2, wherein deflecting means are located immediately before said transfer zone.
- 12. The press section of claim 1, wherein said conditioning means comprise a conditioning nip defined between a first and second roll arranged along a vertical axis, after said transfer zone and in connection with said loop of said transfer band fabric.
Priority Claims (1)
Number |
Date |
Country |
Kind |
916026 |
Dec 1991 |
FIX |
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Parent Case Info
This application is a continuation-in-part of U.S. Ser. No. 07/829,989 filed Feb. 3, 1992.
US Referenced Citations (15)
Foreign Referenced Citations (7)
Number |
Date |
Country |
771159 |
Dec 1971 |
BEX |
1068525 |
Dec 1979 |
CAX |
82500 |
Aug 1986 |
FIX |
885737 |
Jun 1990 |
FIX |
2269893 |
Nov 1990 |
JPX |
697774 |
Sep 1953 |
GBX |
2039308 |
Aug 1980 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
829989 |
Feb 1992 |
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