Method and device for enhancing the run of a paper web in a paper machine

An arrangement for enhancing a run of a web in a paper machine from a press section to a dryer section, comprising

• a press nip arranged in the press section,
• a first impingement drying dryer group arranged after said press nip in a running direction of the web, said first impingement drying dryer group comprising
• a first permeable fabric on which the web is supported,
• guide means for guiding said first permeable fabric in a loop, said guide means comprising a plurality of guide rolls, said guide means being structured and arranged to guide said first permeable fabric while the web is supported thereon in a substantially straight run or a run having a large radius of curvature defined over at least two of said guide rolls, and
• blow means for directing a heated medium at the web at a region in which the web is supported by said first permeable fabric in said substantially straight run or said run having a large radius of curvature, said blow means comprising a first impingement drying unit having a front face and arranged on a first side of the web and a second impingement drying unit having a front face and arranged on a second side of the web opposite said first side of the web, the heated medium being directed at the web from both said first and second impingement drying units;
• a second dryer group having single-wire draw arranged after said first dryer group in the running direction of the web, and
• support faces for carrying the web from said press nip through said first dryer group to said second dryer group, at least one of said support faces always being in engagement with the web such that the web is passed as a closed draw from said press nip to said second dryer group, said support faces comprising said first permeable fabric which is arranged to carry the web between said first and second impingement units.

A method for enhancing the run of a web in a paper machine, comprising the steps of:

• dewatering the web in a press section by pressing the web in at least one press nip,
• drying the web in at least one impingement drying dryer group arranged after the at least one press nip, said web drying step comprising the steps of:
• supporting the web on a first permeable fabric,
• guiding the first permeable fabric and a second permeable fabric while the web is supported on the first permeable fabric in a joint substantially straight run or run having a large radius of curvature defined over a plurality of guide rolls,
• arranging an impingement drying device in each of a loop of the first permeable fabric and a loop of the second permeable fabric, and
• directing a heated medium at the web from the impingement drying devices at a region in which the web is supported by the first permeable fabric in said substantially straight run or said run having a large radius of curvature;
• drying the web in at least one dryer group having single-wire draw after the web is dried in the at least one impingement drying dryer group,
• passing the web from the at least one press nip in the press section into the at least one dryer group having single-wire draw as a closed draw, and
• constantly supporting the web against at least one support face during its passage from the at least one press nip in the press section, into and through the at least one impingement drying dryer group and into the at least one dryer group having single-wire draw.

An arrangement for enhancing a run of a web in a paper machine from a press section to a dryer section, comprising

• a press nip arranged in the press section,
• a first dryer group arranged after said press nip in a running direction of the web, said first impingement drying dryer group comprising a permeable fabric on which the web is supported,
• a first permeable fabric on which the web is supported,
• a second permeable fabric,
• guide means for guiding said first and second permeable fabrics each in a respective loop, said guide means comprising a plurality of guide rolls, said guide means being structured and arranged to guide said first and second permeable fabrics while the web is supported on said first permeable fabric in a joint substantially straight run or run having a large radius of curvature defined over at least two of said guide rolls, and
• blow means arranged in said loop of said first permeable fabric and said loop of said second permeable fabric for directing a heated medium at the web at a region in which the web is supported by said first permeable fabric in said substantially straight run or said run having a large radius of curvature;
• a second dryer group having single-wire draw arranged after said first dryer group in the running direction of the web, and
• support faces for carrying the web from said press nip through said first dryer group to said second dryer group, at least one of said support faces always being in engagement with the web such that the web is passed as a closed draw from said press nip to said second dryer group.