Abstract: A filter for thickening fiber suspensions or other liquids containing solid material includes a plurality of rotatable filter disks (3) mutually spaced in axial direction and adapted to be partially submerged in a liquid (5) to be filtered. Each filter disk includes a plurality of filter sectors (4) communicating with axial filtrate discharge ducts (2) at the outer peripheries of the filter disks (3) for removal of filtrate. The axial filtrate discharge ducts (2) are open to atmosphere at at least one end (2') thereof for the purpose of conducting air through these ducts into the interior of the filter sections to replace filtrate flowing out. Advantageously, there is communication between all axial filtrate discharge ducts through annular filter disk holders (1) carrying the filter sectors (4) of the filter disks.

Abstract: In a disk-type decker that is employed to drain suspensions and that has axially distributed suspension chambers and filtrate chambers that are separated by rotating screen disks and open into a stationary tub, the filtrate chambers are evacuated to increase the throughput of the decker and improve and accelerate drainage. The filtrate chambers are for this purpose divided by radial and axial transverse partitions into individual filtrate-chamber sections distributed along the circumference and sealed off from one another. When the screen disks and hence the filtrate-chamber sections rotate and the sections enter into flow engagement with filtrate outlets at the bottom of the decker, they are simultaneously evacuated, accelerating drainage through the disks. The results are a higher throughput, a lower material density in the filtrate, and lower specific investment costs at the same throughput or material density in the filtrate.

Abstract: In rotating disc filters used for example in the pulp and paper industry, one or more spray elements are positioned between adjacent discs to rotate about an axis parallel to the disc axis. This arrangement achieves greater washing coverage of the discs than prior systems.

Abstract: A filtering method in which an object to be filtered and dewatered is brought through a finely porous suction face saturated with liquid, into hydraulic connection with a liquid situated under a negative pressure relative to the object to be dewatered. The filter plate or equivalent and the material to be filtered which adheres to the plate by the liquid suction, are surrounded by a pressure-tight cover. A positive pressure relative to atmospheric pressure is introduced into this cover, by which removal of liquid out of the material to be filtered is intensified. A device for providing such filtration is also provided.

Abstract: The present invention relates to a method and apparatus for discharging a disc filter. The method and apparatus are excellent for handling fiber suspensions in the pulp and paper industry. In earlier known means, the filter cake thickened on the filter surfaces of the disc filter is detached by means of water or compressed-air jets and the cake allowed to freely fall to an axial chute disposed below the shaft level of the filter, wherefrom the pulp most usually is transferred by means of a screw conveyor. The pulp, however, easily clogs the inlet opening of the chute, whereby pulp material accumulates in the space between the discs with harmful consequences.

Abstract: A continuous discharge centrifuge can separate a slurry into a solid and liquid portion. The centrifuge has a housing and a rotor mounted in the housing to spin at a predetermined rate. The centrifuge has a spaced plurality of filters peripherally mounted on the rotor for separating the liquid portion by admitting it under centrifugal force. Also included is a spaced plurality of passage columns mounted between adjacent pairs of the filters. The columns can engage the outside of filters and conduct the solid portion upon the filters between it and the passage columns.

Abstract: The present invention relates to a method and an apparatus for washing pulp according to which method the pulp is supplied onto a movable liquid-pervious support surface (2) to form a substantially continuous layer (7); and washing liquid is supplied to the pulp layer and passed in several successive washing phases through different areas of the layer in such a way that the washing liquid gradually flows in the opposite direction compared with the flow direction of the pulp layer. According to the invention the washing liquid is divided in two or more partial flows which pass alternately through different washing phases in such a way that the washing liquid which in one phase has passed through the pulp layer flows past at least the washing phase preceding it in the flow direction of the pulp layer. The apparatus of the invention preferably comprises a rotating cylinder (1) the casting surface (2) of which serves as the liquid-pervious support surface for the pulp.

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: A rotatable filter assembly, primarily intended for separation of fibers from a fiber suspension, comprises a number of annular filter discs (3) formed by a plurality of filter elements (5). The filter discs are mounted on a horizontal drum rotatable in a container (1) and formed by axial discharge tubes (6) and transverse tubes (7) which communicate with the individual filter elements (5). A collecting hopper (8) extends into the drum through an open end of it. During at least part of the rotation of the drum, the interior of each filter element (5) is kept at a pressure lower than that prevailing at the outside of it. The filter assembly is characterized in that the axial discharge tubes (6), as seen in a cross-sectional view, are arranged in groups each comprising at least two tubes.

Abstract: A method for improving the operation of a disc filter used for the filtering of fluids containing solid matter such as fibers. Known filtering methods have the drawback that the rate of water exhaustion is limited, because a vacuum tends to be created inside the sectors when the filtered fluid is drained by suction from the central channel of the disc filter. This drawback is an obstacle to increasing the speed of rotation and therefore to increasing the capacity of the disc filter. With the method of the present invention, this problem is solved by providing the disc filter with a means of admitting ambient air into the disc sectors and the central shaft channel and/or with equipment for blowing air into the sectors and the channel to remove the filtered fluid from them.

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.

Abstract: An apparatus for separating loose paper pieces from a bath of caustic soda including a tank with a hopper-like structure disposed at the top of the tank. A helical screw conveyor is operatively disposed below the hopper and has its discharge exteriorly of the tank. A pair of perforated stainless steel screen-type spaced rotatable drums is operatively disposed between the hopper and the conveyor, and a hollow stainless steel screen-type cylindrical filter (with a nylon filter cover) is positioned in the bottom of the tank and has an outlet extending to the tank exterior. In operation, a caustic soda solution mixed with paper pieces in the hopper is discharged by gravity onto the rotating drums which feed the paper pieces via the outer (rotating) drum surfaces into the conveyor and then to the exterior of the tank. The caustic soda solution flows through the perforations in the drums and then to the bottom of the tank and through the cylindrical filter for final filtering and then to the tank exterior.

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.

Abstract: A sludge condensation and dewatering apparatus is described which comprises a condensation unit and a dewatering unit. The condensation unit comprises a flocculating reaction tank (1) for forming a sludge flock, a first holding tank (2) slantingly arranged and upwardly inclined along the moving direction of the sludge, a conveyor for conveying the sludge flock from the flocculation tank to the holding tank for retaining the sludge flock produced by the flocculation reaction tank and an endless running screen belt (3) located just below and adjacent to the first holding tank, a dewatering unit, a solidification device (13) in communication with the first holding tank located between the condensation unit and the dewatering unit. The dewatering unit comprises an upper running piled filter cloth (4) and a lower running piled filter cloth (5), a plurality of rolls (R.sub.1 -R.sub.

Abstract: Filtering apparatus includes a shell with at least one filter leaf mounted in the shell to be rotatable about an axis. Means are provided for forcing a solid-containing liquid into the shell and into the leaf to form a cake of solids on the leaf. Means are also provided for removing filtered liquid from the leaf and the shell. A nozzle in the shell is disposed adjacent the leaf to direct a jet of sluicing liquid against the leaf as the leaf rotates. A sluicing liquid is supplied to the nozzle to wash solids from the leaf, and means are provided for moving the nozzle toward and away from the axis of leaf rotation in a plane substantially parallel to the leaf to remove solids from the leaf.

Abstract: A pair of rotatable shafts are mounted within a housing. The shafts are spaced apart along the same plane with each shaft having a plurality of longitudinally spaced disks mounted thereon. The space between the shafts and the dimensions of the disks are such that disks on each shaft extend into the space between adjacent disks on the other shaft to provide pressing areas. One shaft is rotated clockwise; the other shaft is rotated counterclockwise.A slurry or semi-solid is fed into the in-running sides of the disks. A cake forms on the disks by the flow of liquid through liquid passageways in the disks. Pressing to a high consistency takes place in the pressing areas. The cake thus formed is removed from the disks at the out-running sides of the disks.

Abstract: A disk-filter apparatus in which a filter disk is rotatable about a horizontal axis and lies substantially in a vertical plane to collect filter cakes on opposite sides of the disk. The filter cakes are each treated with a liquid from an array of ducts parallel to the filter cake and from which the liquid is distributed onto the filter cake. The ducts of each array are supplied at least in part through overflow boxes or weirs to control the pressure. The number of openings, spacing of the ducts and opening size are all selected to obtain the most homogeneous distribution of liquid onto the filter cakes that is possible.

Abstract: Apparatus is disclosed for steam drying a cake of filtered solids formed on a disc filter element of a rotary disc vacuum filter where the disc filter element is mounted on a rotating means for rotation in a container, the lower portion of which includes a slurry tank and the upper portion of which includes a steam hood. The steam hood encloses a portion of the disc filter element in a steam chamber and includes a pair of sidewalls and a spine wall which joins the pair of sidewalls. A linear seal means is mounted to the pair of sidewalls of the hood to define a steam-retaining exit for the steam chamber through which the disc filter element rotatably moves, and includes two elongated flexible flaps which extend in a straight line from the spine wall into the slurry tank.

Abstract: A filter apparatus has an elongated shaft, a plurality of filtering elements mounted on the shaft and spaced from one another in direction of elongation of the latter, and means for cleaning the filtering elements. The cleaning means includes a source of cleaning medium under elevated pressure and a plurality of nozzle elements communicating with this source. The nozzle elements face toward surfaces of filtering material provided on the filter elements and are turnable relative to these surfaces. The cleaning medium is ejected from the nozzle elements at a pressure between substantially 5 and 100 bar toward the surfaces of the filtering material of the filter elements so that the cleaning medium removes a cake deposited during a filtering process from the surfaces of the filtering material and thereupon also cleans the filtering material of the filter elements.

Abstract: An apparatus for filtering liquids comprises a substantially cylindrical shaped and horizontally placed filter-casing in which at least one supporting member is journaled for rotation substantially about the axis of the casing. The supporting member is provided with a number of hollow rotating shafts, evenly spaced around its axis of rotation, and each shaft carries at least one disc-shaped filter-element. The filtrate discharge from the disc-shaped filter elements passes through the hollow rotating shafts to an outlet-conduit mounted stationary with respect to the supporting member. A conveying trough provided with a conveying screw is arranged substantially in aligmment with the axis of rotation of the supporting member to transport the filter-cake dislodged from the filter-elements and received by the trough out of the filter-casing.

Abstract: A filter arrangement for thickening suspensions of fibrous material is shown as having rotating filter elements encased in a filter trough with such filter elements being pairs of filter disks fixed at right angles to a rotary hollow shaft and further defining a chamber as between such filter disks; the chambers are connected through the hollow shaft to a suction head to which down-pipes are linked and in which material outlet shafts are disposed between the pairs of filter disks; turbulence generating means are provided in the filter trough and the filter disks are provided with at least one ejector vane.

Abstract: A filtering apparatus with hollow filters that are alternately placed under reduced pressure and positive pressure. The filters are reciprocally rotated through a cycle along a 180.degree. arcuate path from immersion in the unfiltered liquid to a discharge station and back again. Whle immersed and under reduced pressure, each filter passes liquid and captures cake against its surface. The filter is kept under reduced pressure and rotated to a discharge station. The reduced pressure during this portion of the cycle holds the cake against the filter and dries it. At the discharge station, the filters are placed under positive pressure to dislodge the cake and kept under positive pressure as they are rotated back toward the unfiltered liquid. The discharge station has movable scrapers that contact the filters as they are being rotated back to the unfiltered liquid to assist in dislodging the cake.

Abstract: An automatic self-cleaning liquid clarification system wherein suspended solids are removed from a contaminated liquid. A hollow drum carrying a plurality of brushing elements mounted on its outer periphery scrubs a strainer or screen and elevates the solid contaminants separated by the screen into a pitched auger conveyor which removes additional liquid from the solids materials which are then conveyed in a semi-dry or damp state for discharge.

Abstract: An apparatus for removing matter accumulated on a filter element, rotatable about a central axis, having an arm portion mounted at an angle relative to the radii extending from the central axis of the filter element and in a stationary position relative thereto. The arm portion supports a flexible means for engaging a surface of the filter element as the element is rotated relative to it to frictionally remove the accumulated matter from the surface. The arm and flexible means are preferably curved outwardly toward the periphery of the filter element to facilitate outward removal of matter while maintaining the integrity of the surface of the filter element.

Abstract: A portable filtration apparatus particularly adapted to remove solid and chemical contaminants from hot cooking liquids used in deep fryers, having a frame, a filter bowl mounted on the frame, a plurality of horizontal filter elements mounted on a hollow, vertical tube within the filter bowl, each of the filter elements having a corresponding cleaning means mounted adjacent it to engage and remove spent filter cake and contaminants from a filtering surface of the element when desired, and a pump mounted on the frame for continuously recirculating liquid through the filtering apparatus or returning filtered liquid to the deep fryer, as controlled by movement of a single valve. The filter elements are rotatable about a central axis of the tube within the filter bowl relative to the stationary cleaning means disposed across the surface of each element, to automatically remove spent filter cake and contaminants and eject them from an opening formed in the bowl.