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US 4,986,009 AGranted
Process for drying a material web and device for the application of the process
AssigneeJ. M. Voith GmbH
InventorsWinfried Haessner, Georg Kugler, Robert Wolf
Life of this patent
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Abstract
Process and device for drying a material web which together with a backing belt alternately runs across heatable drying cylinders which are contacted by the material web and across guide rolls contacted by the backing belt. At the travel section of the material web from one drying cylinder to the next, drying air is fed to the material web in relatively narrow blow zones. Located between the narrow blow zones are relatively wide steam release spaces from which the water vapor-laden drying air is removed.
Claims26
Process for drying a material web comprising:
- passing the material web, along with a porous backing belt, alternately across contact zones on heatable rolls which are contacted by the material web and across the guide rolls which are contacted by the backing belt such that a free web surface exists in a section of web travel contained between adjacent contact zones;
- supplying drying air from outside each contact zone to the free web surface in drying air blow zones which in the direction of web travel are relatively narrow, with the drying air blow zones alternating in the direction of web travel with steam release spaces which in the direction of web travel are relatively wide, with the ratio of the length of each drying air blow zone to the length of each steam release space being maximally 1/20, such that the material web outside the contact zones repeatedly and alternately passes by drying air blow zones and steam release spaces.
Device for drying a material web comprising:
- a plurality of heatable rolls arranged in a row;
- a plurality of guide rolls arranged in a row generally parallel to that of the heatable rolls;
- a backing belt which together with the material web meanders alternately across the heatable rolls and across the guide rolls, the heatable rolls each being contacted by the material web and forming a contact zone, the guide rolls each making contact with the backing belt;
- a drying device arranged in an area outside the contact zones and including means for feeding drying air at the surface of the material web in several blow zones which in the direction of web travel are relatively narrow and in the direction of web travel are arranged successively, said blow zones extending transverse to the direction of web travel;
- said drying device including steam release spaces arranged on both ends of each blow zone in the direction of web travel, said steam release spaces being relatively wide in the direction of web travel, with the ratio of the width of an individual blow zone to the width of an individual steam release space, each measured in the direction of web travel, being maximally 1/20;
- and
- means for removing water vapor-laden drying air from the steam release spaces.
4 more elements
Dependencies are inferred from the claim text.