摘要 |
METHOD AND APPARATUS FOR PRODUCING UNIFORM PULP YIELDS An improved method and apparatus for producing uniform pulp yields, wherein at least a refiner is controlled in accordance with the UV absorbance of the lignin dissolved in the digester cooking liquor, thereby to produce for a given quantity of wood chips a unform pulp yield. A backflow control valve is automatically adjusted to maintain uniform flow of a sample of the digester cooking liquor through a UV analyzer, and a flushing arrangement is provided for flushing out contaminates such as sulphur dioxide from the system. Preferably the refiner is of the two- stage type, the first stage being automatically adjusted as a function of the UV absorbance of the digester cooking liquor, and the second stage being automatically adjusted as a function of the freshness of the output fiber slurry. Also, one or more of the cooking parameters is controlled by the UV analyzer to control the fiber yield. |