Double-sieve former for paper-manufacturing machine includes three-layer sieves of specified thickness and construction, with width-stretching rollers

摘要

Over the circumferential area (6) of the sieve (4) running over the first roller (7) (or other guide), a three-layer sieve of SSB type with a thickness of up to 0.6 mm is provided. Over the circumferential area (8) of the sieve (5) running over the second roller (9) (or other guide), a three-layer sieve of SSB type, with sieve thickness of up to 0.67 mm, is provided. Preferably width-stretching rollers (15) also precede each roller (7, 9) in the direction of sieve running (S). The sieve (4, 5) has an internally-open volume of up to 420 cm3>/m2>. The permeability is preferably 360-400 CFM. A width-stretching roller and/or a CSR roller is/are employed in succession. The first roller is a forming roller, the second a breast roller.