Abstract: Frames holding separate sections of a filter medium, each covering a section of the perforated sidewall of an annual disc of a device for filtering liquids are held in sealing arrangement with the sidewall by a circumferential holding system containing a circumferential groove engaging the frame, which in a preferred embodiment can be slidingly inserted and removed.

Abstract: In a hydrocyclone plant for treating fibre suspensions comprising a multiplicity of hydrocyclone bodies (1) each hydrocyclone body is mounted in a hole in a wall (5) and is sealed to the wall with the aid of a sealing ring (18). According to the invention the sealing ring is made of an inexpensive chemical resistant material and is radially cut through, so that two free ends are formed on the sealing ring. The hydrocyclone body is provided with a sealing surface (12) having a radial extension which increases along the hydrocyclone body. Axially along the sealing surface (12) a projection (22) extends between the free ends of the sealing ring. When mounting the hydrocyclone body the sealing ring (8) is adapted to be entrained by the wall (5) along the sealing surface (12), so that the sealing ring is expanded and seals between the sealing surface and the wall.

Abstract: A separation device for suspensions comprises a housing (1), a filter body (3) with a wall of filter material situated in the housing, spray means (14) adapted to spray jets of a suspension to be separated directly onto one side of the wall of filter material, and means (4, 6) for displacing the filter body relative to the spray means. According to the invention the filter body forms a substantially circular cylindrical drum (3) with a vertical center axis, the circumferential wall of the drum comprises said wall of filter material. Further, said displacement means (4, 6) is adapted to turn said cylindrical drum about said vertical center axis during operation.

Abstract: A suspension containing fine and coarse particles is sprayed under high pressure by way of spray nozzles (10) against a rotating filter medium (7), so that the suspension is separated into a fine fraction, which passes through the filter medium and which contains said fine particles, and a coarse fraction, which does not pass through the filter medium and which contains said coarse particles. According to the invention the filter medium (7) is rotated by way of a drive motor (6) at a speed such that coarse particles and liquid developing on the side of the filter medium are removed from the filter medium substantially as the result of the centrifugal force the coarse particles and liquid are subjected to. In consequence the filter medium is efficiently kept clean during operation, which increases the capacity and improves the separation efficiency.

Abstract: A hydrocyclone plant comprises a great number of hydrocyclones (1) arranged in a plurality of separate assemblies (10, 10A, 10B). Each hydrocyclone assembly includes branch pipes (6, 6A), to which the hydrocyclones of the assembly are connected in parallel relationship to one another. There are main pipes (13) of the same number as that of the branch pipes of each assembly, the branch pipes of each assembly being connected to said main pipes, respectively. According to the invention, clamping means (8, 9) are provided for releasably clamping each hydrocyclone substantially transversely against at least one of the associated branch pipes (6, 6A) of the latter, and the individual assemblies include various numbers of hydrocyclones, for optimizing the desired capacity of the hydrocyclone plant.

Abstract: A hydrocyclone plant comprises a multiplicity of hydrocyclones arranged in groups of at least two hydrocyclones, each group being made in a single piece. The hydrocyclones extend substantially radially in an annular space for a liquid mixture to be separated. The inlet space extends concentrically around a cylindrical heavy fraction space for receiving a heavy fraction of the liquid mixture from the hydrocyclones. According to the invention, the hydrocyclone groups are distributed around the cylindrical heavy fraction space in the circumferential direction and are spaced from one another in the inlet space to allow the liquid mixture to flow between adjacent hydrocyclone groups.

Abstract: A hydrocyclone assembly comprises at least one hydrocyclone (1) having at least two through flow members (2, 3) for distribution of liquid between the outside and the interior of the hydrocyclone, and circular cylindrical pipes (4, 5) of the same number as that of the through flow members of the hydrocyclone, the through flow members of the hydrocyclone being connected to the pipes, respectively. According to the invention each through flow member (2, 3) defines an annular end portion (6), which extends around a radial bore (7) in its associated pipe (4, 5) and abuts sealingly against the mantle surface of the pipe via a gasket (8) extending around said bore in the pipe.

Abstract: A fibre suspension is separated by a filter device having a hollow filter body (1) with a wall (2) of filter material, and a container (3). The entire fibre suspension to be separated is sprayed in the form of at least one liquid jet onto said wall (2) to force a fine fraction of the suspension containing most of said undesired particles through said wall of filter material into the hollow filter body, thereby leaving a created coarse fraction of the fibre suspension mainly containing fibres in the container outside the filter body. Relative displacement between the liquid jet and the filter material is provided. Said created coarse fraction is dewatered through the wall of filter material, and said dewatered coarse fraction is discharged from the container.

Abstract: An improved apparatus and process for fractionating pulp suspensions consists of multiple interchangeable modular treating compartments stacked atop one another. Pulp suspension is fractionated in the first compartment, and one of the two resulting fractions flows gravitationally to a second compartment where it is fractionated further. Any of the resulting fractions may be fractionated still further in subsequent compartments as many times as desired. The treating compartments are interchangeable, so removal, addition, or replacement of compartments is relatively easy and quick. Fractionation in each compartment is carried out through centrifugal force.

Abstract: An apparatus for dewatering and squeezing a water containing material comprises a drum with a sieve mantle defining two co-operating drum sections, each comprising a feed screw extending therein. The first section of the drum in the feed direction is formed for dewatering of the material mainly by self-drainage. The first drum section is rotatable and is provided with means for cleaning the sieve mantle holes. The second section is formed for increased compression of the material, and has a thread height for the feed screw smaller at the outlet of the second section than at the inlet to this section.

Abstract: A method of cleaning green liquor of solid particulate impurities by adding caustic lime corresponding to 0.5 to 10% of the amount of caustic lime needed for complete causticizing of the green liquor to the green liquor in a soda dissolving tank or in a separate mixing tank to which the liquor is led directly from the dissolving tank. Calcium carbonate precipitates and forms, with the impurities, particles having better settling and filtration properties than particles in green liquor which has not been treated with caustic lime.

Abstract: In a method and an apparatus for mixing chemicals into a fibre pulp, the pulp passes in a space between a fixed casing and a rotating device through three treatment sections. In the first treatment section a transport screw is arranged for transporting the pulp and impart to it a pressure up to the subsequent treatment section. In this treatment section both the casing and the rotating device are provided with guide elements which cause shearing between the fibre layers of the pulp by alternating velocity gradiants in the pulp and oscillating movement thereof. In the next treatment section the pulp is imparted a retarding velocity in a first part of the section and thereafter an accelerating velocity in a second part of the section during simultaneous oscillating movement and shearing between the fibre layers. This is accomplished by a configuration of both the fixed casing and the rotating device in the form of double-cones having their basis abutting each other.