Patent DE-102008052162-A1 (DE)
Title: Device for producing material web e.g. paper/cardboard, comprises headbox for spraying fibrous material on forming web, hybrid former, press section comprising extended nip, dry part comprising drying cylinders, and on-line coating portion
Inventor: RAUTIAINEN PENTTI
IPC: D21G1/00
Filed: 2008-10-31
Abstract: The device for producing a material web such as paper or cardboard, comprises a headbox (101), with which a fibrous material is sprayed on a forming web (110) of a sheet forming part, a hybrid former (100) comprising a wire section and a twin-wire section having a non-pulsating dehydration zone (131) or a pulsating dehydration zone (132, 133), a press section comprising an extended nip (NP1), a dry part comprising drying cylinders with a filter guidance, an on-line coating portion, an afterdrying portion, an on-line ribbon calender, and an on-line winder. The device for producing a material web such as paper or cardboard, comprises a headbox (101), with which a fibrous material is sprayed on a forming web (110) of a sheet forming part, a hybrid former (100) comprising a wire section and a twin-wire section having a non-pulsating dehydration zone (131) or a pulsating dehydration zone (132, 133), a press section comprising an extended nip (NP1) and introduced into a closed guidance of the web, a dry part comprising drying cylinders with a filter guidance, an on-line coating portion, to which a non-coated web is guided and is coated through a contactless spray coating, an afterdrying portion, in which the coated web is dried by contactless dryers, an on-line ribbon calender, in which the web is polished in the nip calender between a metal band and a heated thermal roller, and an on-line winder, in which the web is rolled. The ribbon calender comprises a device for heating the metal band of the calanders, is used as end- or front calender and is present between the afterdrying portion and winder or between the dry part and the coating portion. The device comprises a soft calender comprising two nips as end calender. The front part of the dry part comprises a horizontal impact air flow dryer, in which the web has a straight or curved flow, and a vertical impact air flow dryer, in which the web has a straight or curved flow. The afterdrying portion comprises drying cylinders. The press section comprises a central roller press, in which the central roller with a suction press roller of a first felt forms a nip press and the central roller with an extended nip roll of a second felt forms an extended nip. A transfer film-like loop runs over the central roller for transferring the web from the central roller to the first reception point, by which the web is directed in closed web or guided over a transfer web in the dry part. The press section comprises a single press, in which a felt-like extended nip is formed between two press rollers. The extended part comprises a spray-coating device, in which high-pressure spray nozzles are inserted in such a manner that the nozzle covers a part of the width of the web measured transverse to the machine direction. An independent claim is included for a procedure for the production of a material web.