| 摘要 |
<p>A paper forming apparatus has a lower looped forming wire (10) disposed for a portion of its travel over a curved apron board (14). The paths of forming wire travel upstream and downstream of the apron board (14) diverge. Such divergence allows a secondary headbox (20) to be brought into such a juxtaposition with the forming wire (10) coming off the apron board (14) as to permit the stock stream to impinge the forming wire (10) both at a low angle and at a short distance to enhance formation of an additional web ply over a previously formed web ply. In one embodiment, an upper looped forming wire (24) is brought into co-running engagement with the lower forming wire (10) over the downwardly extending downstream path of travel. In two-wire embodiments, the turning roll (26) for the upstream end of the upper forming wire (24) is downstream of both the headbox slice (13) and apron board (14) to permit the headbox slice (13) to be positioned close to the lower forming wire (10) and allow the stock stream to be projected downwardly to impinge the lower forming wire (10) at a small angle or a short distance from the slice (13), or both.</p> |
