Method for hot-pressing of a web
US4976820A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 28, 1988 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Apr 28, 2008 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21F3/045
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Method for pressing and dewatering a paper web, in which a hot-pressing stage is utilized where the wet paper web is pressed in direct contact with a cylinder face that has been heated to a temperature higher than about 100.degree. C. A relatively long pressing time and a relatively low compression pressure are applied in a pre-heating/pre-pressing stage. In this preliminary stage, a surface layer of the cylinder that heats the paper web is heated to a temperature higher than about 100.degree. C. In the immediately following stage, the compression pressure applied to the paper web is lowered so that vaporization of the water present in the paper web is intensified. Next, the web is passed substantially immediately into an intensive nip-pressing stage in which the web is pressed with a peak pressure, preferably higher by one order, so that water vapor is blown through the paper web, thereby causing some of the water present in intermediate spaces between fibers in the web to be blown out, and intensifying dewatering.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.