| 摘要 |
<p>The invention relates to a multi-layer web former for forming a three-layer paper web, advantageously a fine paper web. The web forming device comprises three successive web forming units, each of them comprising a headbox (12, 22, 32) and a twin-wire zone (14, 24, 34) formed on the joint run of two parallel wire loops (10, 18; 18, 20; 20, 30), in the region of which zone a forming roll (16, 26, 36) and a number of dewatering elements (17, 19; 27, 29; 37, 39) are acting. The middle layer of the web is arranged to be formed in the first web forming unit (12, 14), the top and bottom layers of the web being then caused to be drained onto the upper and lower surfaces of said middle layer in the two subsequent web forming units (22, 24; 32, 34). The forming roll (26, 36) of the second and the third web forming unit is so placed that both of the new stock layers can be sprayed into a gap between the forming roll (26, 36) and the middle layer of the web formed first. Advantageously, removal of water in the web forming zones (14, 24, 34) is arranged to take place substantially in both directions through both wires (10, 18; 18, 20; 20, 30) confining the web.</p> |
