Wet method of preparing fiberboard products in a substantially closed and balanced white water system
US4221630A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1978 |
| Grant date | Sep 9, 1980 |
| Priority date | — |
| Expiry date | Apr 20, 1998 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21F1/66
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method of making fiberboard using a substantially closed white water system. One or more layers of separately prepared surface pulp is applied to a layer of base pulp at the wet sheet forming stage. Lignocellulose chips in a pressure-sealed defibrating zone under generation of steam. The steam is separated at the discharge end of the defibrating zone under atmospheric pressure. The atmospheric steam is utilized to presteam the raw chips. The presteamed chips are thereafter dewatered to a moisture content coordinated to the energy demand of the defibrating treatment and the desired generation of steam prior to entering the defibrating zone. The water removed at the dewatering stage is collected for use in preparing the surface layer pulp suspension. A small portion of the base pulp to be used for the surface layer pulp is diverted to a refiner and diluted with water. The major portion of the base pulp is diluted with white water drained off and recycled from the base layer wet sheet forming stage to form a base layer suspension, which suspension is then transported by the white water to the wet sheet forming stage, where the white water and recycled to the base layer suspension st…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.