METHOD AND APPARATUS FOR EFFICIENTLY PRODUCING CELLULOSIC PULP BY THE THERMO MECHANICAL PULPING METHOD

摘要

Method and apparatus for producing cellulosic pulp by the thermo-mechanical pulping method wherein wood chips are contacted with gaseous steam at a temperature and for a time sufficient to bring the temperature of the chips close to that of the steam, compacting the resulting steam treated chips while mechanically conveying the same to reduce the moisture content and produce a compacted moist mass, shredding the compacted mass while further conveying the same under more severe conditions than the original conveying and then passing the shredded mass into a refiner. The apparatus of the present invention preferably takes the form of a pair of coaxially operating worm type conveyors with the end of one conveyor being journalled in the end of the other, and operating under conditions such that the second conveyor tends to pull the compacted mass faster than it is being delivered and thereby provides a shredding action to maintain a fairly uniform input into the refiner stage.