| 摘要 |
1. Process for producing a pulp of cellulose fibres not to be used for paper-making, by passing wood chips into a pulping machine comprising at least two screws (1, 2) having identical threads meshing in one another and driven in rotation on the inside of a sleeve (3) provided with an upstream chip inflow orifice (31) and with a downstream pulped-material cutflow orifice (32), the threads (11, 21) of the screws (1, 2) having varied pitches determining a succession of processing zones (I, II etc.), each comprising a section (A) with a direct pitch for driving the material downstream and a section (B) with a reversed pitch for increasing pressure as a result of the braking of the material, the threads with reverse pitches being provided with apertures (12, 22) for the downstream passage of the material which has reached the desired degree of pulping, the sleeve (3) being provided with filtering parts (34) located upstream of the reverse-pitch braking sections (B), at least in the first two processing zones (I, II), in order to carry out drying of the material, characterised in that the material ist first brought to the desired degree of pulping by being passed through the first processing zones (I, II, III), which incorporate reverse-pitch sections (B) provided with apertures, the width of which decreases from one zone to the next to a width of the order of 4 to 5 mm, in that, at the same time, drying together with filtration is carried out to a degree of dryness of between 35% and 55%, and in that the shives and clusters of fibres are subsequently eliminated in the same machine, without reducing the length of the fibres and without carrying out any fibrillation, by passing the pulped and dried material through at least two additional processing zones (IV, V), which incorporate reverse-pitch braking sections provided with apertures having the same width of the order of 4 to 5 mm as in the last pulping zone (III), and a homegenous pulp consisting solely of isolated fibres which have not undergone any fibrillation is obtained at the outlet of the machine. |
