摘要:
A method of and equipment for manufacturing a fibrous web, comprising the formation of at least one layer of fibrous web from stock with a solids content of over 1.5%, water being removed from the said fibrous web by first pressing the fibrous web to a solids content of about 45 to 65%, then evaporating the fibrous web to a solids content of about 75 to 95%, after which the fibrous web is treated by means of a pressing contact to increase its smoothness, the fibrous web being treated in the manufacturing process before the reeling stage by at least one pressure and heat treatment, wherein the forming pressure exerted on the fibrous web is not higher than 20MPa.
摘要:
A forming section comprises a lower wire loop (11) which constitutes a first single- wire section (Tl) following a breast roll (12). The beginning of the first single- wire section comprises a first dewatering zone (Zl) which consists of at least one stationary, first forming shoe (40) and a pulsating strip cover (50) following it. In the first forming shoe, there are a leading edge and a trailing edge as well as a cover provided with through holes and underpressure affecting through the holes of the cover. The holes are constituted of openings or slots substantially in the longitudinal direction of the machine, whereby non-pulsating dewatering is applied on the stock travelling on top of the lower wire. The forming section further comprises a multi-layer headbox (30) by means of which a pulp suspension jet is fed at an impact point after the leading edge of the first forming shoe. The cover of the first forming shoe is straight at least on the section between the impact point of the pulp suspension jet and the trailing edge of the first forming shoe.
摘要:
Multi-layer web formation section having at least two successive wire units (300, 310), which have one wire (11) in common. A first headbox (100) supplies fibre pulp to the forward end of the first wire unit (300) and a second headbox (110) supplies a new fibre pulp layer to the forward end of the second wire unit (310) atop a first partial web (W1) formed in the first wire unit (300). In the forward end of a two-wire stretch of the second wire unit (310) there is a first non-pulsating dewatering zone (Z1b), which comprises at least one first formation shoe (200b), which has a curved cap (201) placed on the side of the new fibre pulp layer and provided with openings (202) extending through the cap (201), and an under-pressure (P) affecting through the cap’s (201) openings (202). A two-wire stretch of the second wire unit (310) has a second pulsating dewatering zone (Z2b), which is formed by fixed dewatering lists (210b), between which there are gaps (220b) and an under-pressure (Pb) affecting in these.
摘要:
The invention concerns an equipment and a method in a twin-wire former, in which a partly pre-drained or non-drained fibre stock is passed to between the forming wires of the web former in the vicinity of the former roll (11) or of a water drain box, in which connection water is drained out of the stock web by means of the former roll (11) or the water drain box. The twin-wire former comprises a rib (20) in connection with the former roll (11) or the water drain box in the lateral area of the wires (H2), which rib has been fitted to control the running of the second forming wire (H2) passed from the gap roll. By means of the rib (20), in the lateral area of the wire runs, the point at which said forming wire (H2) reaches contact with the first forming wire in connection with the former roll (11) or the water drain box is shifted further away in the machine direction. The rib (20) is an oblong structure, which has a maximal height (Hmax) in the middle area of the rib (20).
摘要:
A method of and equipment for manufacturing a fibrous web, comprising the formation of at least one layer of fibrous web from stock with a solids content of over 1.5%, water being removed from the said fibrous web by first pressing the fibrous web to a solids content of about 45 to 65%, then evaporating the fibrous web to a solids content of about 75 to 95%, after which the fibrous web is treated by means of a pressing contact to increase its smoothness, the fibrous web being treated in the manufacturing process before the reeling stage by at least one pressure and heat treatment, wherein the forming pressure exerted on the fibrous web is not higher than 20MPa.
摘要:
Multi-layer web formation section having at least two successive wire units (300, 310). A first headbox (100) supplies a pulp suspension jet to the forward end of the first wire unit (300) to form a first partial web (W1). A second headbox (110) supplies a pulp suspension jet into a jaw (G2) at the forward end of the second wire unit (310) to form a second partial web (W2). The second partial web (W2) is joined to the first partial web (W1) at a joint (N1) in between the second wire unit (310) and a bottom wire (11). In the forward end of a two-wire stretch of the second wire unit (310) there is a first non-pulsating dewatering zone (Z1b), which is formed by a fixed first formation shoe (200b), which has a curved cap (201) placed against one side of the two-wire stretch and provided with openings (202) extending through the cap (201), and an under-pressure (P) affecting through the cap’s (201) openings (202). A two-wire stretch of the second wire unit (310) has a second pulsating dewatering zone (Z2b), which is formed by fixed dewatering lists (210b) in the cross machine direction, between which there are gaps (220b), and an under-pressure (Pb) affecting in these.
摘要:
The invention concerns an equipment and a method in a twin-wire former, in which a partly pre-drained or non-drained fibre stock is passed to between the forming wires of the web former in the vicinity of the former roll (11) or of a water drain box, in which connection water is drained out of the stock web by means of the former roll (11) or the water drain box. The twin-wire former comprises a rib (20) in connection with the former roll (11) or the water drain box in the lateral area of the wires (H2), which rib has been fitted to control the running of the second forming wire (H2) passed from the gap roll. By means of the rib (20), in the lateral area of the wire runs, the point at which said forming wire (H2) reaches contact with the first forming wire in connection with the former roll (11) or the water drain box is shifted further away in the machine direction. The rib (20) is an oblong structure, which has a maximal height (Hmax) in the middle area of the rib (20).