Paper coating system and method
US5076200A · kind A · utility
Inventors
Key dates
| Filing date | Oct 12, 1990 |
| Grant date | Dec 31, 1991 |
| Priority date | — |
| Expiry date | Oct 12, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05C11/04
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A paper coating system is characterized by an upstream dip roll applicator that applies an excess layer of liquid coating material onto a surface of a paper web, and an improved downstream doctor assembly for metering and leveling the coating on the web. The doctor assembly includes a doctor blade having a tip extended against and across the web and a shear plate, upstream of the blade, having a surface extending across and defining a gap with the web. An elongate chamber defined between the shear plate and blade extends across the web, and excess coating removed from the web by the blade flows into the chamber. Coating is drained from and uniformly along a lower end of the chamber at a rate to maintain an eddy current pool of coating in an upper end of the chamber immediately upstream of the blade/web nip, but to prevent formation of a liquid seal in the gap. The eddy current pool of coating rewets the excess coating on the web just prior to the blade to level and smooth streaky film split patterns that occur from dip roll application, so the blade doctors the coating very uniformly and a very uniform coating is on the finished paper sheet. To further improve uniformity, the shear…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.