Alfa-laval Separation Ab

Goran Krook

Per Karlsson

In connection with recirculation of separated sludge to the separation chamber of a centrifuge separator there are normally flow restricting nozzles in the sludge outlets of the separation chamber. Only after all separated sludge has passed through these nozzles it is divided into one discharge flow and one recirculation flow. The invention concerns a centrifugal separator with a recirculation circuit (27, 28, 33, 39, 41, 43, 32, 30, 29) for separated sludge, which is completely free of flow restricting nozzles. The amount of separated sludge, that is allowed to leave the centrifugal separator through the outlet conduit (39) without being recirculated, is determined by setting of valves (22, 40) in the stationary outlet conduits (21, 39) for sludge and clarified liquid, respectively.

Centrifugal separator with recirculation of separated sludge

The invention resides in the provision of a sludge recirculation controlled in this manner within the centrifuge rotor itself. For this reason there has been arranged centrally in the rotor, apart from a previously known reception chamber (10) for separated sludge, a recirculation chamber (14) to which sludge is transferred from the reception chamber (10). An overflow outlet (15) maintains a free liquid surface in the recirculation chamber (14) at a predetermined radial level. Recirculation channels (16), which are formed so that the flow therethrough will automatically be controlled depending upon the viscosity of the separated sludge, will conduct such sludge from the recirculation chamber (14) back to the radially outermost parts of the separation chamber (5).

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Stockholm, Sweden

Goran Krook