FI121475B - Method with forming member and forming member - Google Patents

Description

Method with forming part and forming part Förfarande i ett formningsparti och foramingsparti

5 TECHNICAL FIELD

The invention relates to a method according to the preamble of claim 1.

The invention further relates to the forming part according to the preamble of claim 6.

BACKGROUND OF THE INVENTION

The forming member serves to remove water from the fiber suspension fed by the headbox. The consistency of the fiber suspension fed to the forming part is generally 1% and the consistency of the web formed after the forming part is 18-20%.

When the web is made from an aqueous fibrous pulp slurry, water in the pulp is removed by the forming member through the forming wire or forming wires to begin forming the web. The wood pulp fibers remain randomly distributed on the forming wire or between co-forming forming wires.

Depending on the quality of the web being manufactured, different types of fiber pulp are used. The amount of water that can be removed from various fiber pulps to provide a good quality web is a function of many factors, such as the desired basis weight of the web, machine design speed, and the desired level of fines, fibers, and fillers in the final product. 1

There are several types of devices known in the former, such as foil moldings, suction boxes, pivoting rolls, suction rolls, and open surface rolls 2, which have been used in a variety of configurations and sequences in an attempt to optimize the amount, time, and location of the Making web is still part of the art and part of the science is that simply removing water as quickly as possible does not produce the best quality end product. In other words, producing a high quality end product, especially at high speeds, is a function of the amount of dewatering, dewatering duration, dewatering duration, and location of the dewatering.

When maintaining or improving the quality of the final product, switching to higher production rates often results in unpredictable problems that either result in lower production to maintain the desired quality or to be sacrificed to achieve higher production.

Fig. 1 of WO 2004/018768 shows a two-wire reformer. The forming fabrics each pass over their own chest roll, after which the forming fabrics form the kid from which the twin-wire portion begins. The twin wire section has at least two drainage zones. The first dewatering zone consists of a curved, non-pulsed forming die and the second dewatering zone consists of a pulsating die cover. The non-pulsed forming shoe is located immediately after the quill closure point and the headbox feeds the pulp suspension to the jet, on an unsupported wire prior to the forming shoe. After the pulsating mold cover, the forming wires run on the surface of the swivel suction roll, from which the outer forming wire is separated and guided through the guide roll to the return cycle. The web then follows the inner forming wire 25 on the surface of the inverted suction roll, after which the web is separated from the inner forming wire and the inner forming wire is guided into the return cycle.

Fig. 3 of WO 2007/096467 shows another twin-wireformer having a short flat wire section, followed by a twin-wire section formed between the lower wire loop and the upper wire loop 30. The headbox supplies a pulp suspension jet with a flat wire portion, to the first vacuum 3 dewatering zone of the forming table within the lower wire loop. This is followed by another pulsating dewatering zone in the formation table, which is depressurized with transverse dewatering strips. This is followed by a twin-wire section having 5 dewatering boxes with three successive dewatering chambers inside the top wire loop. The first dewatering chamber of the dewatering box is provided with a curved, non-pulsating forming shoe and the latter two dewatering chambers are provided with pulsating dewatering ducts. Following the dewatering box, there are dewatering fixtures underneath the bottom wire loop, after which the top wire is separated from the bottom wire and the web follows the wire to the transfer point.

Fig. 5 of WO 2008/000900 shows a third twin-wireformer having a short flat wire section, followed by a twin-wire section formed between a lower wire loop and an upper wire loop. The headbox feeds the pulp suspension jet on the flat wire portion, to the first, non-pulsed dewatering zone of the forming shoe within the bottom wire loop. This is followed by another pulsating dewatering zone of the forming shoe with a depressurized transverse dewatering strip. This is followed by a twin-wire portion having a formation within the upper wire loop. The two-wire portion begins here with a curved dewatering zone on the surface of the forming roll. The forming shoe cover is straight in the area of the first dewatering zone and the forming roll is a suction roll. Alternatively, the second, pulsating dewatering zone of the forming shoe, i.e. the strip cover, may be located after the forming roll.

In prior art solutions, the chest generally consists of a non-pulsating forming shoe and a subsequent pulsating molding cover. With such a chest structure, the upper surface of the fiber suspension becomes slower to the speed of the wire, so that the properties of the upper surface can no longer be adequately adjusted after the chest. The low pressure, pulsating die cover also causes great friction to the wire as the wire is absorbed at the gaps between the transverse strips of the die cover. High friction, in turn, increases the energy consumption of the forming part.

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SUMMARY OF THE INVENTION

The forming part according to the invention achieves a high drainage capacity, a simple structure and a small space requirement. The forming part of the invention can be used to produce a web of low porosity, high tensile strength and high pile strength.

The main features of the process according to the invention are set forth in the characterizing part of claim 1 of claim 10.

The main features of the forming part according to the invention are presented in the characterizing part of claim 6.

Other features of the invention are set forth in the dependent claims.

In the solution according to the invention, the first wire passes over the first breast roll and the second wire passes over the second breast roll so that a narrowing gap is formed between the wire by the wire section after the breast rolls. Immediately after the first breast roll, a first fixed, non-pulsed forming shoe is disposed within the first wire loop and immediately after the second breast roll, a second solid, non-pulsed forming shoe is placed inside the second wire loop. The inlet edge of the second forming shoe coincides with the outermost edge of the first forming shoe. The headbox supplies a pulp suspension jet in the region of the first forming shoe to the surface of the first wire. The first wire is guided to the second wire in the region of the second forming shoe.

The first forming shoe has a lid 30 with through-holes, at the beginning of which the headbox feeds a pulp suspension jet. It is intended that the first forming shoe will not cause pulsating dewatering even when dewatering is effected under reduced pressure. The cover of the first forming shoe has a large open area and can be connected via openings to a vacuum chamber inside the forming shoe. The openings in the forming shoe cover are formed so as to avoid pulsating dewatering, which would result if the openings were formed by transverse elongated slots in the machine. To provide this substantially constant pressure, these openings are either holes, substantially machine-directional slots, corrugated slots, raised machine-directional contact surfaces for supporting the fabric above the shoe cover, etc. The holes may have a circular, square, ellipse or polygonal shape.

When the headbox pulp suspension jet is directed over the first non-pulsating formation shoe, the take off and stock jump jet of the pulp suspension jet can be substantially reduced because the pulp suspension jet 15 descends to a non-pulsed surface with a large open area. Immediate initiation of dewatering at the point of impact dampens impact energy. The tip of the list table does not scour the water and is not contributing to the 'stock jump'. The shower also has a flexible orientation. 1 2 3 4 5 6 7 8 9 10 11

The second forming shoe also has a cover with through openings, and the structure of the second forming shoe 2 is substantially similar to that of the first forming shoe 3. It is intended that the second forming shoe 4 also does not cause pulsating dewatering, even when dewatering is effected under vacuum.

6 7

The non-pulsed forming shoes can be used to remove water from a very wet web 8 without breaking the structure of the web since there is no vacuum peak on the leaving side of the solid forming shoe 9. The depression 10, which is coupled to the forming shoe, provides a very efficient dewatering and, by adjusting the vacuum level 11, can influence the dewatering distribution between the upper and lower surface of the web. the fines distribution between the upper and lower surfaces of the web and the Z-direction symmetry of the web can be controlled. The forming part according to the invention is capable of producing a fibrous web having a very uniform orientation of the fiber in the thickness direction of the fibrous web.

5 The high dewatering capacity of the non-pulsed forming shoes allows for lower headroom and a larger than normal lip opening in the headbox. Lower feed consistency improves the formation of the web to be formed.

In the solution of the invention, dewatering through the upper surface of the pulp suspension begins with the second forming shoe immediately at the point where dewatering through the lower surface of the pulp suspension with the first forming shoe ends. In this case, the velocity of the upper surface of the pulp suspension is still substantially the same as the velocity of the mouthpiece of the headbox. The second forming shoe is able to influence the fiber orientation of the upper surface of the fibrous web in such a space condition, thereby providing a uniform fiber orientation over the entire thickness of the fibrous web.

With the solution of the invention, the frictional pressure between the forming wires on the fiber suspension is initially very low. The first wire comes in contact with the second wire 20 in the region of the second forming shoe where the force of clamping the wire together is not yet very high. For example, the high frictional pressure of the cathodicformer causes a large zone of change in orientation on the web surfaces. With low frictional pressure, the fiber orientation of the web is made uniform throughout the thickness of the fiber web. Further, when dewatering through the lower surface and the upper surface of the fibrous web occurs at different times over the upper and lower surface of the fibrous web, a better shear strength is obtained. The peel strength is improved when some of the fines contained in the web migrate back into the middle portion of the web in the region of the second forming shoe.

The solution according to the invention can be used to control the one-sided side of the web well. 30 One-sided management (especially the underside) is important for SC and LWC quality. The dewatering adjustability provides a good opportunity to optimize the symmetry of the final product 7. Controlled web sealing is achieved by applying a vacuum to the web surface.

The invention will now be described with reference to the figures in the accompanying drawings.

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BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a schematic side view of a forming member according to the invention.

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Figure 2 is an enlarged view of the beginning of the forming member shown in Figure 1.

Figure 3 shows the beginning of another forming part according to the invention.

Figure 4 shows the layer orientation of the fibers of the web as a function of the thickness direction of the web.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 is a schematic side view of a forming part according to the invention.

The forming part comprises a first wire loop 11 which rotates over the first chest roll 12 and a second wire loop 21 which rotates over the second chest roll 22. The direction of travel of the first wire 11 is indicated by arrow S1 and the direction of travel of the second wire 21 is indicated by arrow S2. The first wire 11 and the second wire 21 form a converging web G and a subsequent twin-wire zone. Within the first wire loop 11, immediately after the first breast roll 12, is located a first dewatering zone Z1 consisting of a first solid, non-pulsed forming shoe 40. The head box 30 feeds a pulp suspension jet to the piston G at the beginning of the first forming shoe 40. Within the second wire loop 21, immediately after the second breast roll 22, is a second dewatering zone Z2 consisting of a second fixed, non-pulsed forming shoe 50. Following the second dewatering zone Z2 is followed by a third dewatering zone Z3 where the wires 11,21 . This is followed by a straight, slightly sloping portion, where at the beginning of the separation point S1, the second wire 21 is separated from the first wire 11 and led to a return cycle. After the separation point S1, the web W follows the first wire 11 to the pick-up point P where the web W is transferred to the pick-up fabric 31 of the press section.

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Figure 2 is an enlarged view of the beginning of the forming member shown in Figure 1.

The first forming shoe 40 has an inlet edge 43 and an outlet edge 44, and a cover 41 provided with apertures 42 that abut against the inner surface of the first wire 11. Preferably, the first forming shoe 40 is connected to a vacuum source (not shown), whereby a vacuum effect P1 is applied to the web through openings 42 of the lid 41 of the first forming shoe 40. The cover 42 of the first forming shoe 40 is preferably straight in the area between at least the point of impact of the mass jet injection jet supplied by the pc box 30 and the leaving edge 44 of the cover 42. The first forming shoe 40 causes the pulp suspension to pass over the first wire 11 without pulsating dewatering. The first forming shoe 40 can remove a large amount of water from the pulp suspension.

The open pin-25 area defined by the openings 42 of the cover 41 of the first forming shoe 40 is 30-90%, preferably 40-70% of the open area 42 between the inlet edge 43 of the cover 41 and the leaving edge 44 of the cover 41.

The holes 42 passing through the lid 41 of the first forming shoe 40 are disposed obliquely against the direction S1 of the first wire 11 passing over the lid 41 such that the angle between the central axes of the holes 42 and the tangent to the outer surface of the lid 41 is 30-60 degrees.

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The structure of the second forming shoe 50 corresponds to that of the first forming shoe 40. The second forming shoe 50 has an inlet edge 53 and an outlet edge 54, and a cover 51 with openings 52 that abut against the inner surface of the second wire 21. Preferably, the second forming shoe 50 is connected to a vacuum source (not shown), whereby a negative pressure P2 is applied to the web through openings 52 in the lid 51 of the second forming shoe 50. The lid 51 of the second forming shoe 50 is straight at the beginning and slightly curved at the end. The second forming shoe 50 causes pulsation dewatering in the wear mass between the first wire 11 and the second wire 21. The second forming shoe 50 can remove a large amount of water from the pulp.

The open area 52 defined by the openings 52 of the lid 51 of the second forming shoe 50 is 30-90%, preferably 40-70%, of the open area 52 between the inlet edge 53 of the lid 51 and the leaving edge 54 of the lid 51.

The holes 52 passing through the lid 51 of the second forming shoe 50 are disposed obliquely against the direction S2 of the second wire 21 passing over the lid 51 so that the angle between the central axes of the holes 52 and the tangent to the outer surface of the lid 51 is 30-60 degrees.

20

There is an overlap H between the first forming shoe 40 and the second forming shoe 50 such that the opening area 52 of the second forming shoe 50 begins immediately at the point where the opening area 42 of the first forming shoe 40 ends. The overlap H is preferably in the range of 10-200 mm. The wires 11, 21 should join in the region of the second forming shoe 25 so that the upper surface of the pulp suspension contacts the second wire 21, i.e. the upper wire, at the beginning of the second forming shoe 50. Thus, dewatering through the upper surface of the pulp suspension through the second wire 21 begins immediately at the beginning of the second forming shoe 50, thereby providing the full effective length of the second forming shoe 50. The initial portion of the second forming shoe 50, which does not yet have dewatering, causes only excess friction and wire wear. The lid of the second forming shoe 50 is preferably curved so that the radius of curvature is in the range of 1-8 m to form a wire mesh to which the pulp suspension is directed.

The third dewatering zone Z3 consists of a dewatering device 100 comprising a static shaft 110 surrounded by a rotating belt 120. The rotating belt 120 forms a movable curved surface. The shaft 110 preferably consists of a hollow body of rectangular cross-section, the outer surface of which is supported by support members 111, 112, 113, 114, which form a path for the belt 120 as well. The web 120 of the strap loop forms a substantially elliptical web 10 having at least one non-elliptical curved portion E1. The curvature of the curve of the curved portion of the curved portion E1 increases progressively in the direction of travel of the strap. It is contemplated that the curved portion E1 will consist of a plurality of short subarrays such that the length of the subarrays radius R1, R2 will progressively decrease in the direction of travel of the belt 120. Thus, the radius R1 of the sub-arc at the beginning of Kaa-15 Reva's portion E1 is larger than the radius R2 of the sub-arc at the end of the curved portion E1.

The forming wires 11, 21 at the third drainage zone Z3 are guided to pass over said curved portion E1 on the outer surface of the transfer belt 120. The mass passing between the forming wires 11,21 is subjected to a dewatering pressure on said curved portion E1, the magnitude of which depends on the ratio T / R of the radius R of the tension T of the wires 11, 21 and of the curved portion of the wires 11, 21. As the radius R of the curved portion E1 decreases progressively, the mass passing between the wires 11,21 is subjected to a progressively increasing dewatering pressure P3. In a situation where at the beginning of the curved portion E1 the radius R1 of the partial arc is 1 m and at the end of the curved portion E1 the radius R2 of the partial arc is 0.1 m, the dewatering pressure P3 increases tenfold from e.g. 10 kPa to 100 kPa. In the third dewatering zone Z3, which begins immediately after the second dewatering zone Z2, the pulp suspension is dewatered via the second, i.e. upper wire 21, as well as in the second dewatering zone Z2, so that the energy in the .

The static hollow shaft 110 of the dewatering device 100 also acts as a lubricant reservoir 5, from which the lubricating pump B pumps lubricant V between the transfer belt 120 and the support member 111. The dewatering device 100 further comprises a scraper K for returning the lubricant carried by the transfer belt 120 back to the lubricant reservoir.

Fig. 3 is a schematic side view of the beginning of another forming member 10 according to the invention, which differs from the embodiment shown in Figs. 1 and 2 with respect to the third dewatering zone Z3. The third dewatering zone Z3 consists of a pivoting suction roll 200 in which the rotating sheath 220 forms a curved moving surface. The pivoting suction roller 200 further has a vacuum zone 210 connected to a vacuum source (not shown), whereby a vacuum effect P30 is applied to the web through the openings of the vacuum suction zone 210 of the pivotable suction roller 200. The vacuum zone 210 of the pivoting suction roller 200 causes pulverulent dewatering of the fibrous mass between the first wire 11 and the second wire 21. The tension and centrifugal force of the wires 11, 21 cause dewatering through the second wire 21 upwards and the vacuum P30 causes the dewatering through the first wire 11 downwards.

The headbox 30 has a lip passageway 31 that terminates in the lip opening 32. The distance between the lower surface 31a of the lip opening 32 and the upper surface of the first wire 11 passing over the first breast roll 12 is in the range of 0 to 10 mm. The free air travel in the air of the pulp suspension jet 32 discharged from the lip 30 of the headbox 30 is in the range of 100-500 mm. The angle of impact of the pulp suspension jet on the first wire 11 is in the range of 0-6 degrees. The pulp suspension jet hits the first wire 11 at the beginning of the opening 42 of the first forming shoe 40. Such a tracked track 30 between headbox 30, first breast roll 12 and first forming shoe 40 helps to prevent the pulp suspension jet from flying off and 12 being a stock jump when it hits the first wire 11. The short free flight of the lip jet helps to keep the lip shower in its desired shape.

Figure 4 shows the layer orientation of the web fibers as a function of the web thickness direction 5. In the graphs A, B, C of Fig. 4, the point K0 of the vertical axis represents the low layer orientation and the point K1 the high layer orientation. The point XO of the horizontal axis represents the lower surface of the web and the point X1 represents the upper surface of the web. The solid line represents the situation achieved by the solution according to the invention and the dashed line represents the state of the art. Graph A illustrates the situation with a jet-to-wire ratio of 1.1, graph B

plot the situation with a jet-to-wire ratio of 0.9 and graph C illustrate the situation with a jet-to-wire ratio of 1.0.

Figure 4 shows that in the prior art solutions, i.e. mainly in the kite-15 formers, the fiber orientation of the web surfaces and the middle portion is very different. The thickness directional strength of the web on the surfaces is different from that of the central web. This may cause the web to crack in the thickness direction, e.g. during the printing process. With the solution of the invention, the layer orientation of the web surfaces and the central portion is maintained at the same level, whereby the strength of the web also remains good over the entire thickness of the web 20. The figure also shows that the solution according to the invention can be used to adjust the level of layer orientation. At a shower-to-wire ratio of 1.0 (curve C), the layer orientation is lower than the non-steady-state shower-wire ratios of 1.1 (curve A) and 0.9 (curve B). 1 2 3 4 5 6

In the embodiments shown in Figs. 1-3, the same vacuum level P1 2 is used throughout the first forming shoe 40 and the same vacuum level P2 throughout the second forming shoe 50. The vacuum level P1 used in the first forming shoe 40 and the vacuum level P2 5 used in the second forming shoe may be the same or different vacuum levels may be used in the forming shoe 40, 50.

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The first forming shoe 40 and the second forming shoe 50 may also be divided into blocks so that different vacuum is applied to the different blocks.

Claims (8)

A method in a forming portion, the method comprising the following steps: 5. a first wire (11) is arranged to run over a first breast roll (12) and a second wire (21) to run over a second breast roll (22) in such manner , between the first (11) and the second (21) wire (21), a tapered gap (G) is formed on a wire section after the first breast roll (12) and the second breast roll (22), - immediately after the first the breast roll (12) forms a first dewatering zone (Z1) formed by a first solid forming shoe (40) having a cover (41) provided with through-openings (42) and a through-hole (42) in the cover (41) acting suppression (P), - with an inlet carriage (30), a pulp suspension beam is measured on the surface of the first wire (11) in the region of the first forming shoe (40), after the second breast roll (22) is formed a second pulse-free dewatering zone (Z2) formed by a second solid forming shoe (50), - the first wire ( 11) is guided to the second wire (21) in the region of the second solid forming shoe (50), characterized in that the method further comprises the following steps: 20. the first forming shoe (40) is made pulse-free by forming the openings (42) by heel or slits substantially in the longitudinal direction of the machine, wherein the pulp suspension running on the first wire (11) is subjected to pulsation-free dewatering in the region of openings (42) on the lid (41) of the first forming shoe (40), the second pulsation-free dewatering zone (Z2) is formed to begin immediately after the first pulsation-free dewatering zone (Z1), - the second solid forming shoe (50) is formed with a cover (51) provided with through-openings (52) and with a through-openings (52) in the cover ( 51) acting vacuum (P2), which openings (52) are formed by heels or slits substantially in the longitudinal direction of the machine, the pulp running between the first (11) and the second (21) wire. The solution is subjected to pulsation-free dewatering in the area with openings (52) on the lid (51) of the second forming shoe (50). 2. A method according to claim 1, characterized in that immediately after the second forming shoe (50) a third pulsation-free dewatering zone (Z3) is formed, which is formed by a dewatering device (100,200) having a curved, moving surface (120,220), above which the first (11) and the second (21) wire are controlled to run, whereby the pulp suspension running between the first (11) and the second (21) wire is subjected to pulsation-free dewatering on the curved, movable surface 10 (120,220). . Method according to claim 2, characterized in that the third pulsation-free dewatering zone (Z3) is formed with a dewatering device (100) having a stationary shaft (110) about which rotates a water impervious belt (120) supported by support means. (11,112,113,114), said band (120) forming a movable curved surface (120), whose radius of curvature (R) decreases progressively in the direction of travel of the first (11) and the second (21) wire, between the first (11) and the second (21) wire pulp suspension is subjected to a progressively increasing dewatering pressure in the third dewatering zone (Z3). 20 Method according to claim 2, characterized in that the third pulsation-free dewatering zone (Z3) is formed by a breaking suction roll (200), the first (11) and the second (21) wire running on the surface of a rotating sheath (220). ) of the suction roller (200) over a suction sector (210) of the suction roller (200), in which the pulp suspension running between the first (11) and the second (21) wire is subjected to a dewatering pressure in the suction section (210) of the suction roller. (200), with a vacuum (P3) acting through apertures in the rotating manifold (120). Method according to any one of claims 1-4, characterized in that an overlap (H), the size of which is 10-200 mm, is formed between the first forming shoe (40) and the second forming shoe (50). A forming portion, comprising: - a first winding loop (11) running over a first breast roll (12), - a second winding loop (21) running over a second breast roll (22), the first ( 11) and the second (21) wire loop form a tapered gap (G) in the section after the first breast roll (12) and the second breast roll (21), - a first dewatering zone (Z1) located immediately after the first breast roll ( 12) and formed by a first solid forming shoe (40) disposed within the first wire loop (11) and having a through-hole (41) provided with a cover (41) and a through-hole (42) - an inlet carriage (30) measuring a pulp suspension beam on the surface of the first wire loop (11) in the region of the first forming shoe (40), - a second pulsation-free dewatering zone (Z2) formed by a second solid forming shoe (50), wherein the first (11) wire is joined to the n the second (21) wire in the region of a lid (51) on the second forming shoe (50), characterized in that: - the openings (42) in the first fixed forming shoe (40) are formed by sliding claws substantially longitudinally of the the pulp suspension 20 running on the first wire (11) is subjected to pulsation-free dewatering in the region of openings (42) on the lid (41) of the first forming shoe (40), - the second pulsation-free dewatering zone (Z2) begins immediately after the the first pulsation-free dewatering zone (Z1), - the second solid forming shoe (50) is disposed within the second winding loop 25 (21) immediately after the second chest roll (22) and it has a cover (51) provided with through-openings (52) and a vacuum (P2) acting through the openings (52) in the lid (51), which openings (52) are formed by heels or slits substantially in the longitudinal direction of the machine, the pulp suspension running between the first (11) and the second (21) wire. It is subjected to pulsation-free dewatering in the region with openings (52) on the lid (51) of the second forming shoe (50). Molding portion according to claim 6, characterized in that it further comprises immediately after the second conducting shoe (50) a third pulsation-free dewatering zone (Z3) formed by a dewatering device (100,200) having a curved, movable surface (120,220). ), over which the first (11) and the second (21) wire are guided to run, the pulp suspension running between the first (11) and the second (21) wire being subjected to pulsation-free dewatering on the curved, movable surface (120,220). ). Molding portion according to claim 7, characterized in that the third pulsation-free dewatering zone (Z3) is formed by a dewatering device (100) comprising a stationary shaft (110) about which rotates a water impervious belt (120) supported by support means. (11,112,113,114), wherein the band (120) forms a movable, curved surface, whose radius of curvature (R) decreases progressively in the direction of travel of the first (11) and the second (21) wire, between the first (11) and the the second (21) wire running pulp suspension is subjected to a progressively increasing dewatering pressure in the third dewatering zone (Z3). Molding portion according to Claim 7, characterized in that the third pulsation-free dewatering zone (Z3) is formed by a breaker suction roll (200) having a rotating sheath (220), on the surface of which the first (11) and the second (21) wire runs over a suction sector (210) on the suction roller (200), in which the pulp suspension running between the first (11) and the second (21) wire is subjected to a dewatering pressure in the suction sector (210) on the vacuum suction roller (200). ), with a throughpressure (P3) acting in the rotating manifold (220). Molding portion according to any of claims 6-9, characterized in that between the first forming shoe (40) and the second forming shoe (50) is an overlap (H), the size of which is 10-200 mm.