| 摘要 |
Procedure in the forming of a paper web and in dewatering the paper pulp suspension. A pulp suspension jet (J) is supplied onto a lower wire (11), water is drained through the lower wire (11), the fibre pulp course (Wo) is conducted into a dewatering and forming zone (L), where water is drained through the wires (11, 31) and the web (W) is conducted onto a pick-up fabric (21). In the forming zone, the joint run of the wires (11, 31) is deflected, a dewatering effect is caused such that water escapes from the pulpe course (Wo) only through the upper wire (31), a change of direction of the run of the wires (11, 31) is caused in the opposite direction, water that has escaped through the upper wire (31) is collected and said water is guided to water collecting means (40, 46), the run of the twin-wire part is deflected in a direction opposite to preceding deflection; and the joint run of the wires (11, 31) and of the pulp course conforms, starting from the single-wire initial part (11a), to sinusoidal path, the ratio of this wave's length lambda to the amplitude H of the wave being in the range lambda /H = 12 to 20. The invention also concerns an upper wire unit (30), with ancillary equipment (41, 43, 45) for remodelling the Fourdrinier wire section of a paper machine. |
