Patent ID: 7918967

Claim:
An apparatus for continuous digestion of wood chip comprising: an upright generally cylindrical vessel having a top end and a bottom end, the top end of the cylindrical vessel being adapted to receive wood chips mixed with a cooking liquor to be treated therein wherein the cylindrical vessel comprises an upper extraction point and a lower extraction point between the top and bottom ends of the vessel wherein the upper extraction point and the lower extraction point withdraw cooking liquor from the vessel without recirculating the cooking liquor back to the vessel; a first conduit integrally attached at a first location being defined by an upper cook zone positioned between the top and bottom ends of the vessel for selectively extracting a first quantity of cooking liquor from the vessel and wherein the first location positioned upstream of a second location being defined by an area between the upper extraction point and the lower extraction point within the vessel where the cooking liquor being at substantially full cooking temperature; a second conduit integrally attached at a third location positioned downstream from the first and second locations of the vessel and at a fourth screen section on the bottom end of the vessel, the second conduit being in fluid communication with a fourth location positioned at a suction side of a makeup liquor pump for selectively extracting a second quantity of cooking liquor from the vessel at the third location and transporting at least a portion of the extracted second quantity of cooking liquor to the fourth location.