Method and arrangement for the treatment of a fiber suspension
AssigneeA. Ahlstrom Corporation
InventorsOlavi Pikka, Hannu Ronkonharju
Life of this patent
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Abstract
A method and apparatus for the treatment of fiber suspensions of the pulp and paper industry, in particular, the so-called postscreening of pulp in the bleaching stage. The method includes that the pulp discharged from a bleaching stage is diluted to the screening consistency, that the pulp is screened in a pressure screen and that the accept fraction is supplied to the subsequent treatment stage at the supply consistency of the stage without a separate thickening stage. The screening is preferably carried out in a narrow-slot screen.
Claims5
A method of treating pulp in a bleaching stage and a postscreening stage including the removal of impurities from the pulp in said postscreening stage at a screening consistency, said method consisting essentially of the steps of:
- diluting pulp from said bleaching stage to said screening consistency,
- screening the pulp in at least one pressure screen to generate an accept fraction and a reject fraction;
- supplying said accept fraction to a subsequent treatment including one of a washing stage, a thickening stage, a drying stage and a bleaching stage at the supply consistency of said stage without a separate thickening stage;
- diluting said reject fraction to a consistency suitable for vortex cleaners;
- introducing said diluted reject fraction into a vortex cleaning plant;
- and,
- introducing accepts from the vortex cleaning plant to said subsequent treatment.
Dependencies are inferred from the claim text.