Method of and arrangement for de-inking fiber
AssigneeN.V. Papierfabriek Gennep
InventorsKarel A. G. Heijs, Antonius J. Dechamps, Robert L. de Jong
Life of this patent
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Abstract
A pulp suspension is de-inked by way of flotation after the suspension is chemically treated to remove impurities. Air is supplied to the chemically treated suspension so as to generate a foam containing the impurities on the surface of the liquid level of the suspension. The foam is drawn off closely above the liquid level and quenched, and an upper layer of the pulp suspension beneath the foam is discharged so as to remove fiber fines contained in the upper layer. Accordingly, the pulp suspension is purified more quickly and effectively than with prior arrangements wherein the foam and the fiber fines were not separately removed.
Claims14
A method of de-inking pulp suspension by way of flotation comprising the steps of chemically treating the pulp suspension, supplying air at a particular level below the liquid level of the chemically treated pulp suspension thereby purifying it of suspended impurities by generating a foam containing the impurities on the surface of the liquid level of the suspension, drawing off the foam closely above the liquid level, quenching the drawn-off foam, and separately discharging, simultaneously with said drawing off step and above the level at which said air supplying step is performed, an upper layer of the pulp suspension directly beneath the liquid level thereby removing fiber fines contained in the upper layer.
An arrangement for de-inking a pulp suspension by way of flotation comprising a tank of given width for containing the suspension, aeration means in the bottom region of said tank for supplying air at a particular level below the liquid level of the suspension to produce a foam containing impurities on the surface of the liquid level of the suspension, means in said tank arranged to be in the region of the liquid level of the pulp suspension for discharging the impurities, said discharging means including at least one elongated drainage element arranged to extend closely above the liquid level and substantially transversely of the entire width of said tank for discharging the foam, and at least one discharge channel arranged to extend substantially transversely of the entire width of said tank, closely below the liquid level and above the level at which air is supplied to the suspension by said aeration means, for separately discharging fiber fines contained in a layer of the pulp suspension directly beneath the liquid level.
Dependencies are inferred from the claim text.