Abstract: A vat (1) with an inlet (2) for a suspension. A rotatable inner axial part (5) with peripheral channels (7) and at least one disc-shaped filter (8) mounted to the inner axial part (5). Within the vat the suspension is contained between partition walls (16A) in which the filters rotate. The filter (8) has inner flow channels (42) for transporting filtrate to channels (7) in the inner axial part (5). The filtrate from the channels (7) is combined in one end of the inner axial part (5) into at least one vacuum forming downpipe (12). Sprays (13) (15) detach material deposited on the filters. Mounted to the top of the partition walls (16A), which form receiving chutes (16), are guide plates (14A) for guiding material down into the chutes. Spray nozzles (14B) are located below the guide plate(s) and between the partition walls (16A) to clean the filtering surface (10).

Abstract: A disc filter for dewatering cellulose fiber suspensions comprising disc-shaped filter elements (11) carried by a rotor shaft (7) in order to rotate inside a vessel (2) while being partly immersed in a suspension received in the vessel. Each filter element comprises several filter sectors (12) distributed about the rotor shaft. Loosening members (25) are provided for loosening fiber material that has been filtered out of the suspension and deposited on a filtering lining (13) of the respective filter element. Receiver chutes (30) are located in the part of the vessel where the filter sectors (12) are rotated down into the suspension from a position above the suspension. The receiver chutes receive loosened fiber material together with flushing liquid from cleaning members (26) located above the receiver chutes to thereby allow the fiber material to be diluted in the receiver chutes to a desired dry content by means of this flushing liquid.

Abstract: A disc filter for dewatering cellulose fibre suspensions comprising disc-shaped filter elements (11) carried by a rotor shaft (7) in order to rotate inside a vessel (2) while being partly immersed in a suspension received in the vessel. Each filter element comprises several filter sectors (12) distributed about the rotor shaft. Loosening members (25) are provided for loosening fibre material that has been filtered out of the suspension and deposited on a filtering lining (13) of the respective filter element. Receiver chutes (30) are located in the part of the vessel where the filter sectors (12) are rotated down into the suspension from a position above the suspension. The receiver chutes receive loosened fibre material together with flushing liquid from cleaning members (26) located above the receiver chutes to thereby allow the fibre material to be diluted in the receiver chutes to a desired dry content by means of this flushing liquid.

Abstract: A filter and a method for filtration is based upon moving a filter surface that is caused to move through a first filtration region (FF) for separation of a prefiltrate and through a second filtration region (KF) for separation of a clear filtrate. A vacuum is applied on the filtrate side of the filtration region (KF). The filtrate region (FF) has two filtration zones (FF1 and FF2) with mutually different pressure conditions. The filtration zone FF1 has atmospheric pressure and the filtration zone FF2 has a pressure that is lower than the pressure of FF1. The pressure change between the filtration zones (FF1 and FF2) occurs in the pre-filtrate region, i.e., before the filter surface has reached the filtrate region (KF).

Abstract: A filter sector for a rotating filter disc has filtrate conduits for filtrate resulting from filtration which is discharged at the more narrow end of the filter sector. The filtrate conduits are outwardly defined by a filtrating layer permeable to the filtrate. The filter sector has at least one element provided with a profiling forming the filtrate conduit. The profiled element itself forms the filtrating layer because the profiled element has a perforation permeable to the filtrate.

Abstract: A filter element for a pressure filter where a substantially horizontal wall (3) divides the interior of a pressure vessel into a lower inlet compartment (5) and an upper outlet compartment (6). A filter element (20) having a filter medium (40) is suspended from the wall (3) such that the filtering takes place from the inlet compartment (5) through the filter element (20) up to the outlet compartment (6). A corrugated sheet (22) is provided which defines a plurality of substantially vertically extending channels (45) and (42). Each first channel (45) is open the inlet compartment (5) with the filter medium (40) covering the first channels (45) with the upper end of the first channels (45) being closed and the lower end of the first channels (45) being open at (43). The second channels (42) being formed on an inner side of the corrugated sheet (22) with an open bottom end and an upper end communicating with the outlet compartment (6).

Abstract: A method for concentrating a suspension comprises the steps of providing a first surface; providing a second surface; introducing a suspension; moving the second surface relative to the first surface; and applying suction to the second surface. The first surface is relatively liquid-tight and includes a feature for increasing friction. The second surface is relatively liquid-pervious, faces the first surface, and is moveable relative to the first surface. Introduction of the suspension between the first and second surfaces forms a suspension web. Moving the second surface relative to the first surface and applying suction through the second surface causes dewatering of the suspension web and increased friction between the suspension web and the second surface.

Abstract: A device for filtering a liquid substance comprising a container (1) having an inlet (2), a rotor (6), an inner rotor part (7), at least one disc filter (8). Spray nozzles are provided for releasing material filtered away from the substance and deposited on the filter disc. Furthermore there are conveyors (17) for removing the material released.

Abstract: A fractionator includes a shaft attached to a drum which is positioned in a housing and which is rotatable about a substantially horizontal axis and has an inlet means for suspension and at least two outlets for fractions. The drum has a first end and a second end and includes at least two fluid tight walls surrounding the axis. The drum also extends in its longitudinal direction between the first end and the second end to define a fluid channel. The fluid channel extrends substantially parallel to the axis from the first end to the second end and continuously in a circumferential direction of at least 360.degree..

Abstract: A fractionator for fractioning a suspension in at least two fractions, including a drum rotatable about a substantially horizontal access and having axially spaced end walls, a centrally arranged inlet for suspension, a flow channel for suspension in the drum, and outlets for fractions. The flow channel extends from the inlet back and forth between the end walls of the drum and radially outwards towards an outlet for the at least two fractions. Preferably the flow channel is defined by substantially concentric cylindrical walls of which every second wall is alternatively tightly connected to one or the other of the two end walls. The fractionator is useful in a continuous fractioning process.

Abstract: A suction head arranged between a filtrate channel and a barometric leg of a rotating filter having at least one filter means communicating with the filtrate channel. The filtrate channel is connected to the barometric leg through the suction head. In order to ensure continuous conveyance of air bubbles brought along the filtrate, the upper internal boundary of the suction head as regards flow towards the barometric leg is nowhere located at a level above the upper internal boundary of the barometric leg.

Abstract: In a chemicals recovery plant in a sulphate pulp mill, in order to provide green liquor with improved sedimentation and filtration properties, there is passed, from a flow (10) of slaked lime and green liquor between a lime slaker (9) and a causticizing tank (1 1), a partial flow (32, 35) to a soda dissolver (2) or to a container (26) for unclarified green liquor provided after the soda dissolver. For this purpose there is provided, in a line (10) between the lime slaker (9) and the causticizing tank (11), a branch line (32, 35) which passes to the soda dissolver (2) or to a container (26) for unclarified green liquor provided after the soda dissolver.

Abstract: A method for controlling a filtration assembly wherein the amount of medium introduced into the filtration assembly is constant, even though the filterability of the medium or the condition of the filters has changed. The working cycle of the filtration assembly changes when the pressure difference across the filter mesh increases over a certain period of time. The control system is capable of distinguishing between the filterability of the medium introduced and the condition of the filter mesh.

Abstract: A filter sector for a filter disk of a rotating filter, including folded or currugated means having ridges and valleys extending in a longitudinal direction of said means to form filtrate channels, and a filtering medium covering said means. Said means includes at least two elements (9, 10), each having parallel riges (12, 11') and valleys (11, 12') and said at least two elements are located in an at least partly overlapping relationship, such that filtrate channels (13) of one element (9) intersect with filtrate channels (14) of the other element (10). Preferably, the filter sector includes two at least substantially equally shaped elements and said elements are disposed such that there is communication between filtrate channels (13, 14) of said elements (9, 10) in zones of said partly overlapping relationship.

Abstract: A filter for continuous filtering of a suspension under pressure and/or vacuum comprises a vessel (1) having a center axle (2) on which filter discs (3) are arranged at a distance from each other along the central axle. The filter discs consist of filter sectors having surrounding filter cloth and internal channels and between the filter sectors and an outlet from the vessel (1) there is a connection in the central axle (2). Moreover, a scraper (7) is arranged for removing the filter cake (8) on the filter cloth obtained during the filtering operation and a vertical outlet pipe (12) receives the scraped-off filter cake material. The central axle (2) is formed with only one common channel for the filtrate and the gas from all filter sectors in the vessel (1) and consists of a tube.

Abstract: A spray tube nozzle adapted to be cleaned during its operation. The nozzle includes a nozzle head having an inlet connectable to a conduit and an outlet for spraying liquid. Within the nozzle head is located a rotatable element defining a through-hole. The through-hole is shaped in such a way that the opening at one end is of relatively small cross-section and at the opposite end of a relatively large cross-section. The rotatable element is sealingly arranged in the nozzle head and has an external groove. The rotatable element can be positioned in at least a first rotational position to facilitate flow of spraying liquid from the conduit, to the nozzle inlet, and through the through-hole in the rotatable element, to the nozzle outlet for forming spray jets at the outlet. A second rotational position allows liquid to be flushed through the conduit by flow of the spraying liquid from the inlet, through the groove, and exiting the nozzle through a flush hole.

Abstract: A filter for continuous filtration of a liquid includes conventionally a vessel having a center shaft on which is arranged at least one rotating filter element defining an inner space for liquid obtained at filtration. Further there is provided a washing device for washing of material deposited on the filter element, a connection between said inner space and outlet means from said vessel and a separator connected to said outlet and adapted for separating filtrate and gas. Means is provided outside said vessel for generating an overpressure in the gas space of the vessel and a lower pressure in the interior of the filter element at least corresponding to the evaporating temperature of the filtrated liquid for evaporation of the liquid in the separator. The separator is provided with a cooling device for cooling the separated gas and an outlet for condensate obtained at cooling.

Abstract: In a method for filtering a suspension through a stationary filter having a vertical filter element arranged in a pressure vessel and for re-conditioning the filter after filtering, the filtrate is discharged from the bottom of the filter element during the main part of the filtering. After filtering, unfiltered suspension is discharged in a known manner from the pressure vessel later to be returned to the suspension inlet. Thereafter, back-wash is performed with another medium other than filtrate, an outlet for material deposited on the filter element being opened for removal of said material together with the back-washing medium. Preferably, before back-wash, drying of the material deposited on the filter element takes place by means of a gas medium circulating within the filtering plant.

Abstract: An apparatus for removing a fiber layer from a rotating disc filter consisting of a number of filter discs mounted side by side on a common shaft includes gas or liquid nozzles for said removal. The spray nozzles are rigidly connected to slide shoes, each of which is guided by a guide rail positioned about the periphery of each filter disc. The slide shoe is arranged with play relative to the guide rail and is suspended as a pendulum.