| 摘要 |
<p>1522167 Paper-making BELOIT CORP 24 Sept 1975 [30 Sept 1974] 39147/75 Heading D2A To manufacture paper having a base layer e.g. of unbleached kraft stock, and a relatively thin liner layer, e.g. of bleached kraft stock, a single stratified jet of stock is discharged from a headbox 33 onto a substantially horizontal wire 28 of a fourdrinier machine with the liner layer 36a adjacent the wire and the base layer 36b above the liner layer such that the lower liner layer 36a can be dewatered, e.g. by forming board 30 and table rolls 31, quickly to prevent intermixing of fibres in the two layers 36a, 36b. As shown in Fig. 6 the headbox 40 preferably used is divided into two separate flow channels by partitions 42 and 45 at the inlet and outlet of diffusers 43a-43e and by a compliant partition 49 anchored at its upstream end to a perforated plate 46 together with other flexible trailing elements 50. The partition 49 has relatively flexible portions 49a, 49c spaced by a relatively stiff portion 49b such that the velocities of the separate stock streams discharged from the slice 48 remain equal. Headboxes of this type are described in U.K. Specifications Nos. 1443540 and 1492323.</p> |
