device for famstellning of treslipmassa

摘要

An apparatus for continuously producing wood pulp from wood shavings comprising a screw which rotates within a hollow cylinder. The hollow interior of the cylinder is divided into a pressure zone and a grinding and bleaching zone, the shavings being subjected to at least partially defibrillation under a high, continuously-increasing pressure in the pressure zone and then being simultaneously further defibrillated and bleached in the grinding and bleaching zone. The grinding and bleaching zone includes a plurality of pin planes, each plane being formed of at least three radially extending pins which project through the wall of the cylinder, the planes being spaced apart along the length of the screw. The pin planes provide a further pressure increase and produce a desired grinding and defibrillation effect, so that wood pulp is produced without damaging the material and a bleaching agent is simultaneously injected into the grinding and bleaching zone, is caused to be distributed thoroughly and uniformly through the fibers. A method for producing wood pulp in a screw press comprising the steps of feeding the shavings into the hollow interior of the cylinder which is divided into two zones, rotating the screw while at least minimizing the rotation of the shavings with the screw to cause the shavings to traverse the first zone so that the pressure acting on the shavings builds up and at least partial defibrillation of the shavings occurs, the shavings then entering the second zone in which they are simultaneously ground and bleached, the grinding being effected by pressing the shavings, by the rotation of the screw, against radially extending pins projecting through the cylinder to the base of the screw, the pins being located in a plurality of pin planes extending transversely to the longitudinal axis of the screw and at least three pins being provided in each plane and the bleaching being effected by injecting a bleaching or other treatment agent into the cylinder in the grinding and bleaching zone, and finally discharging the thus produced wood pulp from the cylinder.