| 摘要 |
<p>In a double sieve web former for a papermaking machine, having (i) support and covering sieves, on a common section of which the paper web being formed is placed under pressure between the sieves, (ii) a forming roll within the loop formed by the support sieve at the start of the common section of the sieves, (iii) a suction zone in the forming roll over which the common section of the sieves runs, (iv) a couch roll having a suction zone in the vicinity of the closed end of the common section, (v) sieve guide rolls so arranged in the running direction of the sieves upstream of the forming roll, that the sieves form a throat in front of the common section. The appts. further comprises (vi) a forming table, within the loops formed by the sieves, and pressed against the appropriate sieve on the sieve section between the guide rolls and forming roll, (vii) a pulp feed box through the lip openings of which the pulp is delivered on the sieve in the forming table, (viii) equipment by means of which the pulp feed angles (alpha 1, alpha 2) of the pulp delivery box can be regulated in relation to the sieve. Offers an acceptable compromise between the factors reducing orientation of the fibres and those improving the web formation, e.g. the rate of dewatering.</p> |
