Method and apparatus for de-inking newsprint using counterflow extractor
US5520780A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 1993 |
| Grant date | May 28, 1996 |
| Priority date | — |
| Expiry date | Nov 30, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/64
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A newspaper de-inking system and process require much less water than conventional de-inking systems and which require much lower capital expenditure. The system removes ink from newspaper pulp in a continuous process using one or more extractors each of which performs a de-inking operation equivalent to 6 or more stages of a conventional de-inking process using reactor tanks. Water and heat are conserved still further by employing an evaporator to separate pure water from the extractor effluent and by recycling the purified water to the extractor and to other components of the system. A particularly preferred extractor employs a counterflow single-screw conveyor the flights of which have slots formed therethrough which extend counter to the direction of screw rotation. The slots permit efficient extraction using relatively little de-inking solution and at the same time obviate the need to periodically reverse the direction of screw rotation to unclog the slots. The flow of de-inking solution through the pulp and flights is determined by the dimension, number, and orientation of the slots, and by the pitch of the screw conveyor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.