Abstract: The present invention relates to a method and arrangement for treating pulp. The method and arrangement according to the invention are suitable for use in production of chemical pulp in situations, where gas must be separated from the pulp and the pulp must be diluted. A characterizing feature of the method and arrangement for treating pulp according to the invention, in which method pulp is transferred from a first pulp treatment apparatus (5) treating pulp in a higher consistency, to a second pulp treatment apparatus (50) treating pulp in a lower consistency, is that gas is separated from the pulp in a consistency higher than said second consistency, pulp is pumped by means of a pump (26) to a second treatment performed in low consistency, with the pulp being diluted with an apparatus (28) located after the pump (26) to said second consistency prior to treatment in said consistency.

Abstract: A non-woven web of fibrous material is produced using a moving foraminous element in the practice of the foam process. A first foam slurry of air, water, fibers and a surfactant is generated and centrifugally pumped into contact with the moving foraminous element. Substantially fiber-free foam is withdrawn from the foraminous element while forming a non-woven web of fibrous material on the foraminous element, and at least a part of the substantially fiber-free foam is used in the generation of the first foam slurry. Recycling is also typically practiced using a centrifugal pump, and the centrifugal pumps are preferably degassing pumps which remove some of the gas from the foam. By practicing the invention it is possible to produce fibrous webs using the foam process that are more than two meters wide, and at a forming speed of more than about 100 m/min (e.g. about 200-500 m/min).

Abstract: A non-woven web of fibrous material is produced using a moving foraminous element in the practice of the foam process. A first foam slurry of air, water, fibers and a surfactant is generated and centrifugally pumped into contact with the moving foraminous element. Substantially fiber-free foam is withdrawn from the foraminous element while forming a non-woven web of fibrous material on the foraminous element, and at least a part of the substantially fiber-free foam is used in the generation of the first foam slurry. Recycling is also typically practiced using a centrifugal pump, and the centrifugal pumps are preferably degassing pumps which remove some of the gas from the foam. By practicing the invention it is possible to produce fibrous webs using the foam process that are more than two meters wide, and at a forming speed of more than about 100 m/min (e.g. about 200-500 m/min).

Abstract: A non-woven web of fibrous material is produced using a moving foraminous element in the practice of the foam process. A first foam slurry of air, water, fibers and a surfactant is generated and centrifugally pumped into contact with the moving foraminous element. Substantially fiber-free foam is withdrawn from the foraminous element while forming a non-woven web of fibrous material on the foraminous element, and at least a part of the substantially fiber-free foam is used in the generation of the first foam slurry. Recycling is also typically practiced using a centrifugal pump, and the centrifugal pumps are preferably degassing pumps which remove some of the gas from the foam. By practicing the invention it is possible to produce fibrous webs using the foam process that are more than two meters wide, and at a forming speed of more than about 100 m/min (e.g. about 200-500 m/min).

Abstract: A mixing device in the form of a centrifugal pump is used to mix gas (typically air) with liquid (typically effluent water, dispersion water, or waste paper pulp suspension, etc.). The pump is provided with a common inlet conduit for both the liquid and the gas so that liquid and gas flow freely and in an arbitrary ratio into the pump, that is there is no controlling or adjusting of the flows. The gas is allowed to either dissolve in the liquid or be mixed as small bubbles with the liquid, and any surplus gas is separated from the mixing device (e.g. by holes in the pump impeller leading to a rear portion of the pump which is attached to a vacuum source, such as a liquid ring pump). The liquid and gas dissolved therein, and small bubbles mixed therein, are discharged from the mixing device at a pressure that is raised from the inlet pressure, due to the action of the impeller, which pressure development enhances the dissolution of gas in the liquid.

Abstract: A method and apparatus for improving a batch cooking process, e.g. providing about 7% increase in discharge time, are provided. The invention is especially suitable for improving modern displacement batch cooking processes. A dedicated pump is mounted directly to each digester and discharges to a common superatmospheric pressure discharge tank.

Abstract: An apparatus for the discharge of a mass tower containing medium to high consistency pulp and operable without the need for further dilution includes a vessel for storing the pulp; a suction duct extending from a zone of moving pulp to a region outside of the tower; and a pump attached to the end of the suction duct for discharging the pulp.