Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/04—Drying on cylinders on two or more drying cylinders
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F7/00—Other details of machines for making continuous webs of paper
  • D21F7/04—Paper-break control devices
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G3/00—Doctors
  • D21G3/04—Doctors for drying cylinders
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G9/00—Other accessories for paper-making machines
  • D21G9/0063—Devices for threading a web tail through a paper-making machine

Definitions

• the invention relates to a dryer section of a machine for producing and / or finishing a paper, board, tissue or another fibrous web, with a plurality of dryer groups, which comprise drying cylinders and guide rollers.
• the fibrous web is lying on a drying wire meandering alternately around the drying cylinder and guided around the guide rollers and touches the lateral surface of the drying cylinder.
• the invention also relates to a method for operating a dryer section.
• Drying sections of this type are known and are used for high-speed paper machines.
• the energy consumption in dryer sections is considerable, especially at high production speeds.
• both paper machine manufacturers and paper manufacturers strive to minimize the energy expenditure in the production process.
• At least one drying cylinder is free of machine-wide scrapers.
• the inventor has recognized on the one hand that the contact pressure of the machine-wide scrapers on the drying cylinder surfaces during paper production accounts for 50% -70% of the drive energy of the dryer section.
• the invention also reduces investment costs by eliminating scrapers and smaller drive motors, in addition to saving energy.
• a machine-wide scraper (10.1, 10.3) is assigned to the last drying cylinder (8.1, 8.2, 8.3). This is especially true in the event that the dryer group is the last of the dryer section. It is also possible if the at least one drying group (3, 4, 5) is free of machine-wide scrapers.
• the at least one drying group (3, 4, 5) in the dryer section (1) at an average solids content of the fibrous web (1 1) of greater than 70%, in particular greater than 75%.
• the at least one drying group is preferably arranged in the rear region of the drying section, pre-drying section or after-drying section, for example as last and / or as penultimate and / or as third-third drying group.
• the first two dryer sections may be equipped with machine-wide scrapers and one or more of the subsequent dryer sections according to the invention, wherein at least one dryer cylinder of a dryer group is free of machine-wide scrapers.
• at least%, or at least 1/3 or at least half of the drying cylinders of a dryer section according to the invention can be designed without machine-wide scrapers.
• the at least one drying group (3, 4, 5) is designed as a single-row drying group with overhead drying cylinders (8, 8.1, 8.2, 8.3).
• the drying section is completely single-row with overhead drying cylinders.
• At least the pre-drying section is executed completely single-row with overhead drying cylinders.
• the machine-wide scrapers (10.1, 10.3) are preferably designed on the drying cylinders (8.1, 8.2, 8.3) on and swiveled executed.
• web stabilizers (7) for stabilizing the run of the fibrous web (1 1) by means of negative pressure arranged between the drying cylinders (8, 8.1, 8.2, 8.3) and the guide rollers (6).
• the guide rollers are evacuated via a connected vacuum system.
• Some web stabilizers have negative pressure zones with respect to the fibrous web and preferably have in the region of the separation of the Fibrous web from the drying cylinder surface a machine-wide take-off zone, in which the negative pressure is more than 700Pa.
• at least 3 web stabilizers have a machine-wide take-off zone, in particular at least%, preferably at least 1/3 of the web stabilizers.
• the web stabilizers following a drying cylinder without scraper preferably have a machine-wide removal zone with a high underpressure of at least 700 Pa.
• tear-off sensors are provided in the dryer section for detecting breaks in the fibrous web (11).
• the tear-off sensors are designed as vacuum sensors and / or as optical sensors. As a result, a rapid detection of a tear of the fibrous web is possible.
• the web peeling devices are in operative connection with the tear sensors, so that when the fibrous web is torn off, it can be quickly knocked off at a preferred location, for example in the region of a reject bin at the end of a transfer section. This avoids further production disruptions and delays.
• the at least one drying group (3, 4, 5) of the dryer section has at least one tear-off sensor.
• each dryer group is associated with a tear sensor with one or more dryer cylinders which are free of a machine wide scraper.
• a tear-off sensor can be provided after every 5th to 6th drying cylinder.
• a one-sided or two-sided application of a medium to the surfaces of the fibrous web such as a glue application.
• the fibrous web is pre-dried to a certain dry content in a pre-drying section, the medium is applied and then further dried in the after-dryer section or finished.
• the invention can also be used advantageously in a post-dryer section and / or a pre-dryer section.
• a narrow edge strip of the fibrous web is guided in sections through the various sections of the paper machine and then widened to the production width of the fibrous web. If a drying group forms the end of a transfer section, it is advantageous if the last drying cylinder of this dryer group is assigned a machine-wide scraper.
• transfer scrapers are provided in the edge region of some or all of the drying cylinders, but in particular in the edge region of the drying cylinders of the dryer section, to which no machine-wide scraper is assigned.
• the transfer scrapers are preferably designed to swing up and down and are applied only during the transfer of the transfer strip to the drying cylinder. Once after the transfer operation of the transfer strip has been driven to the production width of the fibrous web, the transfer scraper are swung back. This can reduce the drive energy during paper production.
• the transfer scrapers are up to 1 m, in particular 0.5m wide.
• a reject container is provided for collecting the resulting during Aufmol. at the beginning of the production process or after a successful demolition or deduction of the fibrous web pulp web residues.
• Another aspect of the invention relates to a method of operating a dryer section of a machine for making and / or finishing a paper, board, tissue or other fibrous web having a plurality of dryer sections comprising drying cylinders and guide rollers, the fibrous web being on a dryer fabric lying meandering alternately around the drying cylinder and guided around the guide rollers and thereby brought into contact with the lateral surface of the drying cylinder.
• at least one drying cylinder is kept free from contacting, machine-wide scrapers during the production operation in at least one drying group.
• the course of the fibrous web is monitored for a disturbance.
• a Bahnabschlag sensible is actuated for knocking off the fibrous web when a fault occurs.
• the figure shows the last three dryer groups 3, 4, 5 of a dryer section 1 of a paper machine. This can also be a pre-drying or after-drying section.
• the drying screens 9.1, 9.2, 9.3 are meandering around the drying cylinders 8, 8.1, 8.2, 8.3 and 6 guided around the evacuated guide rollers.
• Each dryer fabric 9.1, 9.2, 9.3, together with the looped drying cylinders 8, 8.1, 8.2, 8.3, the looped deflection rollers 6 and other associated units each have a drying group 3, 4, 5.
• drying groups 3, 4, 5 these are single-row dryer groups with overhead drying cylinders 8, 8.1, 8.2, 8.3.
• the guide rollers 6 are arranged in a below the drying cylinders 8, 8.1, 8.2, 8.3 horizontal plane.
• the fibrous web 1 1 is guided on the respective dryer fabric 9.1, 9.2, 9.3 lying through the dryer groups 3, 4, 5, wherein the fibrous web 1 1 in direct contact with the surfaces the heated drying cylinder 8, 8.1, 8.2, 8.3 comes and is dried.
• the fibrous web is transferred to the drying wire 8.2, 8.3 of the following drying group 4, 5.
• the drying section is housed for energetic reasons by a drying hood 2.
• This last drying cylinder 8.3 forms the end of a transfer section, so that the transferred fibrous web strip and the residual fibrous web are controlled during the transfer operation for a short time controlled in the waste container.
• the last three dryer groups 3, 4, 5 in the dryer section 1 are arranged at a mean dry content of the fibrous web 1 1 of greater than 70%, in particular greater than 75%.
• the drying cylinders of the first two drying groups, not shown are each assigned a machine-wide scraper. In this area, the fibrous web has a low dry content, whereby the adhesion to the surface of the drying cylinder is high.
• the machine-wide scrapers 10. 1, 10. 3 are preferably designed so that they can be swung up and down to the drying cylinders 8. 1, 8. 2, 8. 3.
• the guide rollers 6 are evacuated via a connected vacuum system.
• the web stabilizers 7 have with respect to the fibrous web 1 1 negative pressure zones and have in the field of detachment of the fibrous web 1 1 of the drying cylinder surface a machine-wide take-off zone, in which the negative pressure is more than 700Pa.
• Each drying group 3, 4, 5 has a tear sensor, not shown.
• the tear-off sensors are designed as vacuum sensors. As a result, a rapid detection of a tear of the fibrous web 1 1 is possible.
• Bruabtschvoriquesen for targeted knocking off the fibrous web (1 1).
• the Bruabtschvoriquesen are in operative connection with the Abrisssensoren so that in an outline of the fibrous web 1 1 at a preferred location, for example in the region of a reject container at the end of a Mathrerabiteses, can be quickly knocked off. This avoids further production disruptions and delays.
• the transfer of an edge strip is done without the usual transfer ropes, that is by a ropeless transfer. This type of transfer is reliable, tear-off and therefore particularly suitable in connection with the invention.

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• 2010
  • 2010-08-04 DE DE201010038875 patent/DE102010038875A1/de not_active Withdrawn
• 2011
  • 2011-07-18 WO PCT/EP2011/062188 patent/WO2012016808A1/de active Application Filing
  • 2011-07-18 EP EP11734073.7A patent/EP2601345A1/de not_active Withdrawn
  • 2011-07-18 CN CN2011800481010A patent/CN103154364A/zh active Pending

Non-Patent Citations (1)

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