Abstract: In a procedure for filtering lime sludge meant to be regenerated to lime. Lime sludge is produced in the causticizing process in a sulphate cellulose mill, where it can be reused after regeneration to lime. In the procedure, lime sludge suspension is filtered on a filter drum in continuous rotation by depositing lime sludge on the drum and detaching part of the superficial layer of the lime sludge on the drum with a scraper so that the deeper lime sludge layer on the drum, which by-passes the scraper, serves as filtering medium for the superficial layer that is detached (as a so-called pre-coat).

Abstract: Hydrocyclone for dividing a fibre suspension into a lighter acceptable fraction containing fibres and a heavier reject fraction containing dirt substances. The hydrocyclone comprising a separation chamber consisting in part of a cylinder part provided with at least one passage for the tangential input of the fibre suspension to be divided into different fractions and having within itself a coaxially disposed tube for removal of the lighter fraction, and in part of a sorter cone on the extension of said cylinder part and on the apex of which has been adjoined a conical nozzle which has been made more abruptly tapering than the cone part and which at its apex has a removal aperture for the heavier fraction.

Abstract: An intermittently operating pressurized filter for concentrating a solid matter suspension, comprising a filtering tank with an inlet conduit provided with a feed pump for introducing under pressure the suspension to be filtered, and a draining conduit provided with valve for removal of the concentrated sludge, and a plurality of filtering elements suspended from the roof, through which the filtrate flows and of which the interior communicates with a filtrate collecting tank located above and which thereby collect on their external surface sludge, which has been arranged to be periodically removed by voiding the pressure within the filtering tank by opening for the suspension therein an exit flow path through a draining conduit. The filtrate in the collecting tank will pass in countercurrent fashion through the filtering elements.

Abstract: A hydrocyclone for dividing fiber suspensions into accept and reject fractions, said hydrocyclone being constituted by a conical separation chamber vertically positioned and having at its lower apex end an outlet aperture for the reject fraction, and a base part associated with the upper end of said separation chamber and provided with at least one inlet opening for the fiber suspension, an accept pipe being arranged coaxially with said separation chamber and said base and passing through the top of said base, said accept pipe having its lower inlet end at a level between said inlet opening for the fiber suspension and said outlet aperture for the reject fraction, and the outer surface of the accept pipe having the shape a truncated cone and being further provided with an annular projecting lip forming a discontinuity in said outer surface, the lower side of the lip, facing the reject outlet, having a curved concave shape in order to deflect part of the vortex impinging thereon back towards the reject outlet.

Abstract: A hydrocyclone assembly consisting of two identical hydrocyclones having accept tubes directed against each other so that the longitudinal axes of the hydrocyclones are aligned, and including a joint feed chamber and a joint accept chamber in which the combined accept fraction from the hydrocyclones accumulates. The accept ends of the hydrocyclones' accept tubes are connected with each other and the accept fractions are conducted into and combined in connecting ducts which communicate with the accept chamber.

Abstract: A hydrocyclone for the separation of a liquid suspension into accept and reject fractions, having a conically converging classification pipe, at the apex of which there is an opening for the reject fraction, and a base part in which there is an axial pipe for the accept fraction, and a minimum of two feed channels for the liquid suspension to be purified, in which the feed channel directs the liquid suspension onto an incline in the circular space between the classification pipe and the accept fraction outlet pipe, and the liquid suspension spray discharges from the incline over the spray in the following feed channel.