Enso-Gutzeit Osakeyhtio

Enso-Gutzeit Oy

Enso-Gutzeit Osakeythio

Matti Lankinen

Holger Engdahl

Jorma Surakka

Raimo O Kohonen

Pentti Vikio

Juhani Kyytsonen

Jaakko Savolainen

Martti Tolvanen

Juha Lumikko

Yrjo Luukkainen

Jukka Niskanen

Markku Kosonen

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). The purpose is to arrange the control of the filtering process so that the dry matter content of the lime sludge detached from the drum is substantially constant, and its essential feature is that the dry matter content of the lime sludge detached from the drum is followed so that when the dry matter content tends to decrease, the speed of rotation of the drum is first raised within a given control range and, after the control range has been used up, the scraper is moved closer to the surface of the drum so that at least part of the deeper lime sludge layer on the drum, serving as filtering medium, is detached and, if the scraper is returned to its earlier position, is replaced with a new lime sludge layer, whereupon the control is again continued with the aid of the drum's speed of rotation.

Procedure for filtering lime sludge meant to be regenerated to lime

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. On the inner surface of the sorter cone and conical nozzle has been disposed at least one guide vane running in the axial direction of the cyclone and which imparts to the heavier fraction, travelling along a spiral path on the inner surface of the sorter cone and of the conical nozzle, a radially inwardly directed component of motion. The guide vane common to both the sorter cone and the conical nozzle is located at their point of juncture.

Hydrocyclone

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. In the pressurized filter the filtrate has been arranged to be removed during the filtering step by a filtrate draining conduit departing from the collecting tank, by effect of the pressure produced by the feed pump in the suspension inlet conduit. The collecting tank is of enclosed construction. The sludge has been arranged to be removed from the surface of the filtering elements by the aid of the hydrostatic pressure of the filtrate in the collecting tank, by placing th draining conduit of the collecting tank under atmospheric pressure.

Pressurized filter

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.

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.

Growing community of inventors

Savonlinna, Finland

Matti Lankinen