A. Ahlstrom Corporation

Pasi H Immonen

Raimo O Kohonen

Kaj Henricson

Pentti A Vikio

Kari Peltonen

Jorma Elonen

Raimo Pitkanen

Heikki Manninen

Jukka Heino

Harry Erlund

Erikki Savolainen

Ramio Kohonen

Method and apparatus for treating a gas containing aqueous fiber suspension in a fiber line process of a pulp mill including at least one of pulp screening, washing and bleaching includes (a) transferring the gas containing fiber suspension at a consistency to a treatment station; (b) treating said fiber suspension at the same level by removing a portion of the water from the fiber suspension so as to generate aqueous filtrate and treated fiber suspension having a relatively higher consistency; (c) simultaneously pumping and degassing the filtrate at the same level; and (d) pumping the treated fiber suspension having the relatively higher consistency away from the treatment station at the same level by imparting to the treated fiber suspension sufficient shear force so as to render the fiber suspension pumpable.

Method and apparatus for treating a gas containing aqueous fiber

A method of separating an aqueous solids containing suspension includes (a) subjecting a first solids containing suspension to centrifugal forces so as to separate the suspension into a first gas containing flow, a second gas-free flow and a third flow; (b) feeding the third flow into a flotation cell having a bottom; (c) introducing air at the bottom of the flotation cell into the third flow for separating from the third flow a fourth partial flow; (d) withdrawing the air containing third flow after the separation of the fourth partial flow from the flotation cell; and (e) subjecting the third flow to the centrifugal forces of step (a). An apparatus for the separation of gas and lightweight material from a gas and lightweight material containing aqueous solids suspension is also described and includes a centrifugal pump for separating the gas and lightweight material from the solids suspension with a suspension inlet and an outlet for the lightweight material; a flotation cell for separating the lightweight material from a solids suspension; and a circulation loop connecting the outlet of the centrifugal pump, the flotation cell and the suspension inlet of the pump.

Method and apparatus for improving flotation separation

A method of removing liquid from a thickener, a filter, a washer or the like water-separating device obviates the need for the conventional use of a long drop leg and large filtrate tank. On an upstream face of a liquid-pervious member, a layer of liquid-containing substance is formed. At a downstream face of the liquid-pervious member, a negative pressure (e.g. partial vacuum) is generated to induce the flow of a liquid or a liquid-and-gas filtrate from the liquid-containing layer through the liquid-pervious member. The filtrate is conducted from the vicinity of the downstream face of the liquid-pervious to an inlet of a filtrate pump; such conducting of filtrate is carried out through an enclosed flow passage whereby the filtrate pump generates at least a portion of the negative pressure at the downstream face of the liquid-pervious member. An apparatus for likewise removing filtrate from a thickener, a filter, a washer or the like industrial filtering device is also disclosed.

Apparatus for removing liquid from the thickeners, filters, and washers

A method of treating a fiber suspension in a disc-type pulp treatment apparatus, wherein the apparatus includes a pressure-proof casing with an inlet for the fiber suspension and a discharge for treated suspension and filtrate, a shaft rotating inside the casing an a plurality of discs arranged on the shaft, and wherein the discs are formed of sectors having filter surfaces between which surfaces is a liquid compartment communicating with the liquid discharge. The method includes feeding the fiber suspension to be treated overpressurized into the casing, filling the casing up with the fiber suspension, carrying out the treatment in a closed airless space and discharging the pulp from the casing.

Method for treating fiber suspension

An apparatus for treating pulp includes a pressure-proof outer casing for a suspension to be treated. A shaft is rotatably arranged in the outer casing and a number of disks are arranged substantially radially on the shaft within the casing. The disks are formed by a number of sectors each having two opposite filter surfaces for allowing liquid from the suspension to be drained therethrough and a liquid compartment between the filter surfaces for the drained liquid or filtrate, so that a substantially annular filter surface is formed. The liquid compartment is in communication with a liquid discharge member. The apparatus further includes members for dividing the annular filter surfaces into two or more portions. The members are stationary relative to the casing, so that the members are used for separating different treatment stages of fiber suspension from one another.

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Savonlinna, Finland

Pasi H Immonen