Abstract: A screen plate (1) for screening of pulp suspensions, comprises a number of elongated at least partially curved screen slots (3). According to the invention every screen slot has a width which is maximally 0.8 mm, and the screen slots bend in such a way that a straight rod, which has a breadth which is less than the width of the screen slot and the length which is 5 mm, is prevented from passing through the screen slot, when the rod extends along the screen plate, independently of how this rod is oriented in relation to the screen slot. At that elongated stiff shives may be separated more efficiently by means of the screen plate. This screen plate may also be used for separating a pulp suspension into a first fraction comprising comparatively stiff fibers and a second fraction comprising comparatively flexible fibers.

Abstract: A separation device for separating contaminants from fiber pulp suspensions, preferably produced from waste paper, comprises a cylindrical screen number (4) and a rotor (7) arranged therein. An annular inlet passage (14) for incoming suspension surrounds a tubular wall (11), which extends from the screen member (4) coaxially with the rotor (7). According to the invention, a flow deflecting wall member (16) extends toward the rotor (7) to a position in which the wall member is axially in front of an open end (12) of the tubular wall (11) and radially inside the tubular wall. Furthermore, the wall member (16) with a cross-sectional area which is substantially less than the cross-sectional area of the annular inlet passage (14).

Abstract: An apparatus for treating a pulp slurry of waste paper including long fibers, short fibers and large and fine impurities includes the step of spraying the slurry through a gaseous medium upon a screen to separate long fibers and large impurities from small fibers and fine impurities.

Abstract: In a method of producing high-yield pulp from pulp chip material containing lignocellulose the material is treated with steam in a steam treating station (1) for driving air out of the material and heating the latter. Heat treated material is mixed in a mixing station (8) with a liquid containing chemicals. The mixture of steam treated material and said liquid is transferred from the mixing station to an impregnation station (25) for impregnating the material by means of said chemicals. Impregnated material is supplied to a refining station (36) for refining the material. According to the invention the steam treated material is mixed with said liquid in proportions, such that the created mixture of material and liquid leaving the mixing station (8) assumes a flowing pumpable consistency. Further, said flowing mixture is pumped from the mixing station (8) to the impregnation station (25).

Abstract: A device for fractionating pulp suspensions has a series of vertical filter sheets attached to a horizontal shaft. Suspension is sprayed against the sheets to effect a separation of coarse and fine solids. Cleansing liquid is also sprayed against the sheets to keep the filter holes open and the fabric sheets are movable with respect to the sprays.

Abstract: A rotatable filter assembly comprises a rotor in a container for fibre suspension. The center of the rotor is formed by axial discharge tubes into which hollow filter elements, forming annular filter discs open. A collecting hopper extends into the center of the filter assembly. The filter elements keep separately, at least during part of the rotation turn, a lower pressure inside than outside.

Abstract: In a hydrocyclone plant for separating a fiber pulp suspension into a light phase and a heavy phase, comprising at least two hydrocyclones (1, 2) connected in series, there is provided a device (20) arranged both for degassing a first stream of separated heavy phase coming from one of said hydrocyclones (1) and a second stream of liquid supplied to dilute the first stream, and for mixing said two streams before they are supplied to the other one of said hydrocyclones (2).

Abstract: An assembly for straining of pulp suspensions and the like comprises a strainer drum (1) mounted in a strainer house (2). One or a plurality of devices (5-9) are provided, in order to free impurity particles from fibers, preferably designed like an impact plate, in the strainer house (2) in the flow path, so that the particles in the stream partly are subject to an impact action, and so that the stream is subjected to a variation in velocity.

Abstract: A rotary filter, formed by a number of annular filter discs (1), mounted substantially parallel on a driving shaft, for the uptake and dewatering of fiber suspension from a container, fiber cakes (5) being formed, adhering to the outer sides of the filter discs (1), is provided with spraying nozzles (3), arranged in a removal zone for removal of said fiber cake (5). The invention consists of supporting elements (4) provided in the removal zone for supporting the fiber cake (5) in its upper loosened part and to prevent it from folding out from the filter disc (1) during the removal process.