ES369117A1 - Two wire former - Google Patents

Abstract

A paper-making machine comprises, in combination, successive first, second and third guides, and first and second forming belts. The first and second belts are arranged to travel, respectively, over the first and second guides through initially close spacing, the stock flow being there introduced between the wires immediately thereafter they travel through gradual convergence and into general parallelism with the web in between, and are maintained parallel as they travel over portions of the first and second guides towards the third guide, over which at least one of the runs travels. The first guide is a non-circularlycurved stationary water-permeable surface defined by the locus of a multiplicity of closelylongitudinally-spaced belt-contacting, transverse edges and the second guide is a rotary member with an open, water-receiving periphery about which the second run is wrapped during the forming zone. As shown, the first member 15 is formed from blades 15a, 15b, 15c, 15d and 15e, with preferably more than 50% open area. The blades may be mounted for adjustment either individually (e.g. 15bb) or collectively (e.g. 17bb). The locus of the wirecontacting edges may be of from H=CDk where H is the distance in inches between the wires, D is the distance from the stock inlet, and C and K are constants, C being from 0.5-1.6, and K from -0.2 to -0.8, depending on circumstances. The second guide may be a suction roll, with the particular suction shell configuration shown. A flexible headbox nozzle J is provided to seal the inlet of stock with wires 11 and 21. Lips J-1 and J-2 are resilient, e.g. of rubber, and plates J-3 and J-4 are metallic to provide stiffness. The head-box is adjustable to allow movement of the direction of the centre-line of flow, C L to alter the ratio of drainage through the first and second members. The belts may be of synthetic materials e.g. nylon, and a saveall and a foil may be provided (Fig. 1B, not shown). The formed web may be picked up from one of the belts, after the other has been removed by the third guide, which may be a solid roll, by means of a felt, and carried by the felt through a wet press between a plain and a grooved roll, pressure being applied by a third roll contacting the grooved roll (Fig. 4B, not shown). The headbox may also be inclined to direct stock upwardly (Fig. 4A, not shown).