Patent ID: 7867363

Claim:
A continuous digester system, comprising: a vertically oriented atmospheric vessel having a top and a bottom; the top of the vessel having means for establishing a pressure in a range of +0.5 bar and −0.5 bar; a rotor disposed on top of the vessel and in operational engagement therewith; an inlet chute disposed directly on top of the rotor; the vessel having a first level (CH LEV) of fibrous comminuted cellulose raw material; the vessel having a second level (LIQ LEV) of a liquid disposed below the first level; the vessel having a concurrent impregnation zone disposed immediately below the second level; the vessel having a first screen disposed below the concurrent impregnation zone; the vessel having a first concurrent cooking zone disposed below the first screen; the vessel having a second screen disposed below the first concurrent cooking zone; an impregnation liquor conduit extending from the second screen to the concurrent impregnation zone; a recirculation conduit extending from the first screen to a bottom of the impregnation zone; a fresh cooking liquor conduit in fluid communication with the recirculation conduit, the fresh cooking liquor conduit containing fresh cooking liquor; and a heater in operative engagement with the recirculation conduit.