GB1262091A - Improvements in and relating to board- or paper-making machines - Google Patents

Abstract

1,262,091. Papermaking. A. T. RANSON (BELOIT CORP.). 23 Jan., 1969 [24 Jan., 1968], No. 3724/68. Heading D2A. In a twin-wire papermaking machine, the upper and lower wires are led over first and second guides through paths that gradually converge in a forming zone where they are wrapped around the upper down-running quadrant of the second guide and then become generally parallel and remain so over a third guide. A large-diameter rotatable roll forms the second guide or part of it, and the first and third guides serve to tension the top belt over it without any restraining means in contact with the belt opposite the forming zone. The slice is arranged to deliver a stream of stock to the convergent zone, preferably in a direction aligned with the first part of that zone. As shown, the wire 53 passes round a first guide roll 54 and the wire 11 over a stationary shoe 71, so that they converge and then pass on to the roll 52 and then over a suction roll 55. The roll 52 may be foraminous or solid. Stock is supplied by the headbox 58 and is dewatered through the upper wire in the zone F5, by the combined effect of the hydraulic head h and centrifugal force 53b and 11b are skimming devices cooperating with the save-alls 53c and 52b. In another embodiment (Fig. 2, not shown), the shoe 71 is omitted, and the wires and stock pass directly to a large roll 42, similar to the roll 52 shown. A series of devices of either kind can be arranged with a common lower wire to form a multiply sheet (Figs. 1 and 4, not shown).