SYSTEM FOR WASHING AND DEWATERING PULP

摘要

Apparatus for washing and dewatering pulp and a system for controlling this apparatus are provided. The apparatus includes a pair of rotatable press rolls installed in vats and including a press nip therebetween, an inlet for feeding the pulp to the press nip, with one of the press rolls being movable in relation to the other and in which the processing of the pulp is determined by the number of variable operating parameters. The system includes apparatus for utilizing the distance between the press rolls as a variable operating parameter, for setting a desired value for a specific control parameter, for measuring the specific control parameter, and for adjusting at least two of the variable operating parameters during operation to maintain the difference between the desired value and the measured value of the specific control parameter below a predetermined difference.

主权项

1. A system for controlling apparatus for washing and dewatering pulp comprising first and second rotatable press rolls, each of said first and second rotatable press rolls having a permeable outer surface, and a vat in which said first and second rotatable press rolls are installed, said first and second rotatable press rolls being juxtaposed with each other to define a press nip for pressing said pulp therebetween, feed means for feeding said pulp in the direction of rotation of said first and second rotatable press rolls through said press nip, at least one of said first and second rotatable press rolls being movable in relation to the other of said first and second rotatable press rolls to vary said press nip, whereby the processing of said pulp in said apparatus is determined by a plurality of variable operating parameters which are variable during operation of said apparatus, said system comprising setting means for setting at least one desired value for a specific control parameter of a plurality of control parameters, measuring means for measuring said specific control parameter, said plurality of variable operating parameters including the distance between said first and second rotatable press rolls, and including adjustment means for adjusting at least two of said plurality of variable operating parameters during operation of said apparatus, said plurality of variable operating parameters including the distance between said first and second rotatable press rolls, in order to maintain the difference between said at least one desired value and the value of said measured specific control parameter below a predetermined difference.