DE102011083308A1 - Sheet forming device for a machine for producing a fibrous web from at least one pulp suspension - Google Patents

Abstract

The invention relates to a sheet forming device (1) for a machine (100) for producing a two- or multi-ply fibrous web from at least two pulp suspensions (3), comprising a first forming unit (A) for forming at least one pulp layer (AL) with two continuous endless screens (4, 5; 4, 4.L, 5), of which the first wire (4; 4, 4.L) runs over a peripheral region of a forming element (6) and then in the region of the forming element (6) to the first Sieve (4, 4, 4.L) forming a wedge-shaped material inlet gap (10), which directly from a first headbox (11.A) which receives at least one fibrous suspension (3) accumulates, the two sieves (4, 5; , 4.L, 5) with the at least one fibrous layer (AL) located between them in the wire direction (S) then at least partially form a double-wire zone (12), wherein in the region of the twin-wire zone (12) and each other of the forming element (6) Formiersaugkasten (13) is arranged with a preferably curved Formierfläche (14), which consists of a plurality of spaced apart and rigid strips (15), via which the two wires (4, 5; 4, 4.L, 5) are guided with the at least one fibrous layer (AL) located between them.

Description

The invention relates to a sheet forming apparatus for a machine for producing a two- or multi-ply fibrous web, in particular a paper, cardboard or packaging paper web of at least two pulp suspensions, comprising a first forming unit for forming at least one pulp layer with two continuous endless screens, of which the first sieve running over a peripheral region of a forming element, in particular a forming roller and the second wire over a peripheral region of a guide element, in particular a breast roll passes and then in the region of the forming element, in particular the forming roller on the first wire to form a wedge-shaped Stoffeinlaufspalts directly from a first Headbox which receives at least one pulp suspension, accumulates, the two screens with the at least one fibrous layer located between them in the wire direction then at least partially form a double-wire zone n, wherein in the region of the twin-wire zone and each other of the forming element, in particular the forming roller, a Formiersaugkasten is arranged with a preferably curved Formierfläche, which consists of a plurality of spaced apart and rigid strips over which guided the two wires with at least one fibrous layer between them a second forming unit for forming at least one further pulp layer with at least one rotating endless screen, and a merge section in which the at least two pulp layers after each unilateral discharge a sieve are combined to form the two- or multi-ply fibrous web and a preferably evacuated Gautscheinrichtung, in particular a preferably evacuated Gautschwalze comprises.

Such a sheet forming apparatus for a machine for producing a two-ply or multi-ply fibrous web is known, for example, from the document EP 0 851 058 A2 known.

The embodiments of this document each show a sheet forming apparatus comprising two forming units, a first forming unit with a single wire and a second forming unit with a twin wire. The single sheet forming device is intended to enable molding of high quality dual or multi-ply fibrous web at high speeds.

Generally, such as from the 1 to 3 the publication EP 0 665 330 A1 or the 3 to 5 the publication DE 10 2009 000 696 A1 It is known, the production of a two- or multi-ply fibrous web at higher machine speeds usually by means of an arrangement of two roll-blade gap formers, so two roll bar gap formers. In this case, by means of the first roll-blade gap former typically a supine position and optionally additionally, if a two-layer headbox is used, a central layer is formed. The further second roll-blade gap former is then used to produce a qualitatively more demanding ceiling layer, which is then thrown onto the at least one further layer. Depending on the overall process or the use of the next press section, the blanket layer can also be formed first, so that it is located on the underside of the two- or multi-ply fibrous web to be produced on further transport into the press section. With such a two roll blade gap former concept, speeds of over 1,600 m / min can be achieved.

At slightly lower speeds up to 1,600 m / min come, such as from the 3 the publication DE-OS 2 059 962 As a rule, hybrid formers are used instead of the gap formers. Thus, at low speeds of up to 1,200 m / min, each layer of the two- or multi-layer fibrous web to be produced is formed on a separate wire.

For reasons of quality, the more demanding ceiling layer must always be formed by means of a separate forming unit. In this case, more valuable fibrous materials, such as fresh fiber pulp with a high long fiber content, are used for this cover layer. This fresh fiber pulp can be both unbleached and bleached. Also, the ceiling layer with optimum quality and coverage should have a minimum fiber weight. In addition, for the processing of these long fiber qualities slightly different settings in the forming unit than for the remaining layers of advantage. The remaining layers, so the supine and the at least one middle layer, however, are made of cheaper fiber materials, such as waste paper. Their fiber length and their required quality are usually lower.

A sheet forming device preferably directly downstream in the machine or Sieblaufrichtung downstream press section must then provide sufficient compaction and increase in strength in the produced two- or multi-layer fibrous web.

It is therefore an object of the invention to develop a sheet forming apparatus of the type mentioned in such a way that a two- or multi-layer fibrous web in an optimal Combination of forming units with special requirements for the single-ply ceiling layer with a basis weight of 30 to 60 g / m ² and at a speed of ≥ 1,600 m / min can be produced energy-efficiently and reliably. The special requirements for the single-ply layer of cover can concern both the raw material (fresh fiber, content of waste paper possible, higher long fiber content, bleached and unbleached) and the quality (formation, strength value, ash content on the rubber side). Furthermore, the at least one further fibrous layer should have a basis weight of up to 150 g / m ² and a particular quality focus should be on a good to very good formation, high strength values and an above-average ash content on the Gautschseite.

This object is achieved in a sheet forming apparatus of the type mentioned in the present invention, that the second forming unit for forming at least one further pulp layer comprises at least two wires, each running over a peripheral region of a guide element, in particular a breast roll, which thereafter in the region of a forming element, in particular a rigid, curved and suctioned Impingementschuhs to form a wedge-shaped Stoffeinlaufspalts directly from a second headbox receives the at least one pulp suspension, converge and then at least in sections forming a twin-wire with the at least one fibrous layer located between them in the wire direction, where in the area the twin-wire zone and one another of the forming element, in particular of the impingement shoe, a forming suction box with a preferably curved forming surface is arranged, which consists of several zueina There are spaced and rigid strips, over which the two wires are guided with the at least one fiber layer located between them, and which forms at least one forming zone, which can be acted upon by a preferably controllable negative pressure, in the wire direction.

The object of the invention is completely solved in this way.

The inventive combination of two different forming units with corresponding constructions and thus properties enables the production of a two- or multi-ply fibrous web whose single-ply ceiling layer at a basis weight of 30 to 60 g / m ² and at a speed of ≥ 1,600 m / min energy efficient and reliable can be produced. Furthermore, the at least one further fibrous material layer can also have a basis weight of up to 150 g / m ² and a special quality focus can be on a good to very good formation, high strength values and an above-average ash content on the rubber side.

In particular, the second forming unit is suitable for producing the above-described ceiling layer with the properties mentioned.

The forming roll may have a roll diameter in the range of from 1,000 to 2,500 mm, preferably from 1,500 to 2,000 mm, in particular from 1,700 to 1,900 mm. This ensures a quick and efficient initial drainage of the introduced pulp suspension.

The two screens of the first forming unit for forming at least one fibrous layer with the at least one fibrous layer between them preferably extend at an angle of 10 to 50 °, preferably 20 to 40 °, in particular 25, in a downstream region of the twin-wire zone in the forming roller to 35 °, down to an imaginary vertical plane. This downward trend provides, inter alia, the advantage of a shortened, but still efficient drainage of the introduced pulp suspension. The twin-wire zone may extend down to an imaginary vertical plane immediately after the end of the first wire from the forming roller in a limited range at an angle of> 0 to 45 °, preferably from> 0 to 30 °, in particular from> 5 to 15 ° ,

In a first preferred embodiment, between the forming suction box arranged in the wire loop of the second wire of the first forming unit for forming at least one fibrous layer and the guttering device arranged in the wire loop of the second or first wire of the first forming unit for forming at least one fibrous layer, in particular skin roller, is a separating device. preferably a curved and evacuated separating element, in particular a roller or a stationary separating sucker, arranged in the wire loop of the second or first sieve of the first forming unit for forming at least one fiber layer. In this case, the first or second sieve is separated from the at least one fibrous layer located on the second or first sieve.

Moreover, the first sieve of the second forming unit for forming at least one further fibrous material layer is preferably designed as a fourdrinier wire. In this case, the first forming unit for forming at least one fibrous material layer is preferably arranged above and in the direction of machine direction of the first sieve of the second forming unit for forming at least one further fibrous material layer before or after the merging section. In addition, the at least one runs by means of the first forming unit formed fiber material layer guided on the second or first wire of the first forming unit into the merging section at an angle to the first wire of the second forming unit formed as a wire for forming at least one further fiber layer which is ≦ 90 °, preferably ≦ 75 °, in particular ≦ 60 °, or ≥ 90 °, preferably ≥ 105 °, in particular ≥ 120 °.

And in a second preferred embodiment, between the forming suction box arranged in the wire loop of the second wire of the first forming unit for forming at least one pulp layer and a separator arranged in the wire loop of the first wire of the first forming unit for forming at least one pulp layer, preferably a curved and evacuated separating element , in particular a roller or a stationary separating sucker, a deflection device, preferably a deflection element, in particular a deflection roller, arranged in the wire loop of the second wire of the first forming unit for forming at least one fiber layer. The separating device separates the second sieve from the at least one fibrous layer located on the first sieve.

The two screens of the first forming unit for forming at least one fibrous layer with the at least one fibrous layer located between them after the deflection, preferably the deflecting element, in particular the guide roller, at an angle, preferably at an angle of> 0 to 45 °, in particular under one Angle from 5 to 25 °, going up to an imaginary horizontal plane.

Moreover, the first wire of the first forming unit for forming at least one fibrous layer is preferably formed as a wire. In this case, the second forming unit for forming at least one further fibrous material layer is preferably arranged above the first sieve of the first forming unit for forming at least one fibrous material layer.

The second forming unit for forming at least one further fibrous material layer thus lies in front of the merging section in the direction of wire winding (entry angle ≦ 90 °) or thereafter (entry angle ≥ 90 °).

Further, between the arranged in the wire loop of the second sieve of the first forming unit for forming at least one pulp layer Formiersaugkasten and arranged in the wire loop of the second sieve of the first forming unit for forming at least one pulp layer deflection device, preferably deflection element, in particular deflection roller, preferably at least one suction box in the wire loop of the first wire of the first forming unit for forming at least one fiber layer arranged.

Also, in the at least one forming zone, opposite the forming suction box disposed in the wire loop of the second wire of the first forming unit for forming at least one fibrous layer and in the wire direction at a distance from the leading edge of the first rigid strip of the forming suction box, preferably at least two between each two adjacent and rigid Moldings of the Formiersaugkastens arranged formation strips provided which are supported by means of resilient elements and which are pressed with a selectable force against the first sieve touching them.

As an alternative to the plurality of formation strips, at least one deflector may also be provided in the at least one forming zone, opposite the forming suction box and in the wire direction at a distance from the leading edge of the first rigid strip of the forming suction box.

The head box of the first forming unit for forming at least one fibrous layer is preferably a headbox having at least two layers and a headbox, which has at least one projecting and preferably flexible separating element in the headbox nozzle, which is preferably designed as a flexible separating blade.

Furthermore, the impingement shoe arranged in the wire loop of the first wire of the second forming unit for forming at least one further fiber layer preferably has a shoe length of 200 to 2,000 mm, preferably 300 to 1,500 mm, in particular 400 to 1,200 mm, and / or a shoe pitch of 20 to 120 mm, preferably from 20 to 100 mm, in particular from 20 to 50 mm.

This second forming unit is particularly suitable for the production of the above-described ceiling layer with the properties mentioned.

Also, in the at least one forming zone, opposite the forming suction box disposed in the wire loop of the second wire of the second forming unit for forming at least one further fiber layer and in the wire direction at a distance from the leading edge of the first rigid strip of the forming suction box, preferably at least two between each two adjacent and rigid strips of Formiersaugkastens arranged formation strips provided which are supported by means of resilient elements and which are pressed with a selectable force against the first sieve touching them.

The headbox of the second forming unit for forming at least one further fibrous layer is preferably at least one headbox and headbox having at least one preferably flexible flow lamella in its headbox, which in turn preferably has a lamella length of ≥ 50% of the nozzle length of the headbox.

Furthermore, a separating device, preferably a curved and evacuated separating element, in particular a roller or a stationary separating sucker, is preferably arranged downstream of the at least one forming zone in the direction of the wire run. In this case, the other sieve is separated from the at least one fibrous layer located on one sieve.

Of course, a machine for producing a two- or multi-ply fibrous web, in particular a paper, cardboard or packaging paper web of at least one pulp suspension may be provided with at least one sheet forming device according to the invention. This results in the aforementioned advantages of the invention.

Here, the sheet forming device is preferably arranged downstream of a press section with at least one shoe press directly in the machine or Sieblaufrichtung. Such a press section leads to a further and marked increase in the dry content of the fibrous web to be produced at a reasonable cost and acceptable quality disadvantages.

The sheet forming device preferably has two forming units for respectively forming at least one fibrous layer, wherein the one forming unit is designed to form a lower fibrous layer, in particular a lower cover layer and wherein the other forming unit for forming at least one further fibrous layer, in particular an upper backsheet and at least one central layer is trained. In this case, the press section has at least one shoe press with a press nip felted on top.

Alternatively, the sheet forming device again preferably has two forming units for respectively forming at least one fibrous layer, wherein the forming unit is, however, designed to form at least one fibrous layer, in particular a lower backsheet or a lower backsheet and a middle layer, and wherein the other forming unit forms an upper fibrous layer , In particular, an upper ceiling layer is formed. In this case, the press section on at least one shoe press.

In both embodiments, the shoe press may have at least one shoe tip with a shoe length of ≥ 200 mm.

Further features and advantages of the invention will become apparent from the following description of several preferred embodiments with reference to the drawings.

Show it

1 to 4 schematic side views of preferred embodiments of a respective sheet forming apparatus according to the invention for a machine for producing a two-ply fibrous web; and

5 and 6 schematic side views of two known press sections, which are preferably used in conjunction with a sheet forming apparatus according to the invention for a machine for producing a two-ply fibrous web.

The 1 to 4 show schematic side views of preferred embodiments of a respective sheet forming device 1 for a machine, not shown 100 for producing a two-ply fibrous web 2 (dashed line) of at least one pulp suspension 3 , In the produced fibrous web 2 in particular, it is a two-ply paper, board or packaging paper web. Of course, the fibrous web to be produced may also be a multilayer fibrous web, wherein the individual fibrous web layers comprise at least one fibrous material layer.

The single sheet forming device 1 comprises a first forming unit A for forming a first pulp layer AL with two circumferential endless screens 4 . 5 , The first sieve 4 runs over a peripheral area 7 a forming element 6 , in particular a forming roller 6.1 and the second sieve 5 runs over a peripheral area 9 a guide element 8th , in particular a breast roll 8.1 , The forming roller 6.1 has a roll diameter 6.1d in the range of 1,000 to 2,500 mm, preferably from 1,500 to 2,000 mm, in particular from 1,700 to 1,900 mm. The second sieve 5 then runs in the area of the forming element 6 , in particular the forming roller 6.1 on the first sieve 4 forming a wedge-shaped material inlet gap 10 which is directly from a first headbox 11.A the at least one pulp suspension 3 picks up. Then the two sieves form 4 . 5 with the first fibrous material layer AL located between them in the direction of wire flow S (arrow), at least in places, a double-wire zone 12 , In the area of the twin-wire zone 12 and each other of the forming element 6 is a forming suction box 13 with a preferably curved forming surface 14 arranged, consisting of several spaced apart and rigid strips 15 exists over which the two sieves 4 . 5 are guided with the first fibrous layer AL located between them, and in the direction of wire direction S (arrow) at least one with a preferably controllable vacuum pu acted upon forming zone 16 formed.

The first forming unit A for forming the first pulp layer AL is referred to in the art as a roll-blade gap former, that is, a roll-bar gap former.

Furthermore, the single sheet forming device comprises 1 a second forming unit B for forming a further, second pulp layer BL with at least one continuous endless screen 19 ,

The single sheet forming device 1 also includes a merging section 17 , in which the two fibrous layers AL, BL after each one-sided removal of a sieve 4 . 20 ; 5 ; 20 ; 5 . 20 ; 5 . 20 forming the two-ply fibrous web 2 be merged and a preferably evacuated Gautscheinrichtung 18 , in particular a preferably suctioned Gautschwalze 18.1 includes.

The second forming unit B for forming the further, second pulp layer BL now comprises two screens 19 . 20 , each over a perimeter area 22 . 24 a guide element 21 . 23 , in particular a breast roll 21.1 . 23.1 to run. Then they run in the area of a forming element 25 , in particular a rigid, curved and suctioned impingement shoe 25.1 forming a wedge-shaped material inlet gap 26 , directly from a second headbox 27.b the at least one pulp suspension 3 takes up, together. And with the pulp layer BL between them, the two screens form 19 . 20 in Sieblaufrichtung S (arrow) then at least in sections a twin-wire zone 28 , In the area of the twin-wire zone 28 and each other of the forming element 25 is a forming suction box 29 with a preferably curved forming surface 30 arranged, consisting of several spaced apart and rigid strips 31 exists over which the two sieves 19 . 20 are guided with the fibrous layer BL located between them and in the direction of wire direction S (arrow) at least one with a preferably controllable vacuum pu acted upon forming zone 32 formed.

The second forming unit B for forming the further, second pulp layer BL is referred to in the art as a blade gap former, that is, a strip gap former.

The two sieves 4 . 5 The first forming unit A for forming the first pulp layer AL extend with the pulp layer AL located between them in one of the forming roller 6.1 in Sieblaufrichtung S (arrow) downstream area of the twin-wire zone 12 at an angle C of 10 to 50 °, preferably from 20 to 40 °, in particular from 25 to 35 °, to an imaginary vertical plane V down. The twin-wire zone 12 can immediately after the expiration of the first sieve 4 from the forming roll 6.1 in a limited range at an angle of> 0 to 45 °, preferably from> 0 to 30 °, in particular from> 5 to 15 °, run down to an imaginary vertical plane.

The 1 to 4 show, as already stated, respectively schematic side views of preferred embodiments of a respective sheet forming device 1 for a machine, not shown 100 for producing a two-ply fibrous web 2 (dashed line) of at least one pulp suspension 3 , The single sheet forming device 1 now exemplarily includes two forming units A, B, which differ in their arrangement and design.

The single sheet forming device 1 also includes a merging section 17 , in which the two fibrous layers AL, BL after each one-sided removal of a sieve 4 . 20 ; 5 ; 20 ; 5 . 19 ; 5 . 20 forming the two-ply fibrous web 2 be merged and a preferably evacuated Gautscheinrichtung 18 , in particular a preferably suctioned Gautschwalze 18.1 includes.

In the two embodiments of 1 and 2 is the first sieve 19 the second forming unit B for forming the further, second pulp layer BL as a wire 19.L educated. And the first forming unit A for forming the first pulp layer AL is arranged above the second forming unit B for forming the further, second pulp layer BL. The first pulp layer AL is thus in the merging section 17 by means of the preferably evacuated Gautscheinrichtung 18 , in particular the preferably suctioned Gautschwalze 18.1 aufgautscht on the other, second pulp layer BL.

The two embodiments of the 1 and 2 differ in that in the embodiment of the 1 the first forming unit A for forming the first pulp layer AL in the direction of the wire feed S (arrow) of the first wire 19 . 19.L the second forming unit B for forming the further, second pulp layer BL before the merge section 17 is arranged.

In addition, between that in the wire loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged Formiersaugkasten 13 and in the sieve loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged Gautscheinrichtung 18 , in particular Gautschwalze 18.1 a separator 33 , preferably a curved and evacuated separating element 33.1 , in particular a roller or a stationary vacuum cleaner, in the wire loop of the second wire 5 the first forming unit A for forming the first pulp layer AL arranged. This will be the first sieve 4 from the first on the second sieve 5 located fibrous layer AL separated.

Thereafter, the first formed by the first forming unit A and on the second screen 5 the first forming unit A guided pulp layer AL in the merge section 17 at an angle D1 to that as a wire 19.1 trained first sieve 19 the second forming unit B for forming the further, second pulp layer BL, which is ≦ 90 °, preferably ≦ 75 °, in particular ≦ 60 °.

In the embodiment of the 2 on the other hand, the first forming unit A is for forming the first pulp layer AL in the direction of the wire feed S (arrow) of the first wire 19 . 19.L the second forming unit B for forming the further, second pulp layer BL after the merging section 17 arranged.

In addition, between that in the wire loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged Formiersaugkasten 13 and the one in the sieve loop of the first sieve 4 the first forming unit A for forming the first pulp layer AL arranged Gautscheinrichtung 18 , in particular Gautschwalze 18.1 a separator 33 , preferably a curved and evacuated separating element 33.1 , in particular a roller or a stationary vacuum cleaner, in the wire loop of the first wire 4 the first forming unit A for forming the first pulp layer AL arranged. This is the second sieve 4 from the first on the first sieve 5 located fibrous layer AL separated.

Thereafter, the first formed by the first forming unit A and on the first screen 4 the first forming unit A guided pulp layer AL in the merge section 17 at an angle D2 to that as a wire 19.1 trained first sieve 19 the second forming unit B for forming the further, second pulp layer BL, which is ≥ 90 °, preferably ≥ 105 °, in particular ≥ 120 °.

The in the 1 and 2 illustrated embodiments of a respective sheet forming device 1 with two forming units A, B are particularly suitable for use in a machine for producing a fibrous web 2 , in particular a paper, cardboard or packaging paper web of at least one pulp suspension 3 , A first forming unit A is preferably used for forming at least one further fibrous layer, in particular an upper backsheet and at least one middle layer, whereas a second forming unit B is used for forming a lower fibrous layer, in particular a lower cover layer.

In this case, the respective sheet forming device 1 preferably arranged downstream of a press section with at least one shoe press with a top-felted press nip directly in the machine or Sieblaufrichtung. Such a press section is from the document EP 1 749 926 B1 ("DuoCentri"; see also 5 ) known. Also, such a press section according to the publications EP 1 077 283 B1 ("Tandem NRP"; see also 6 ) and EP 1 048 780 B1 ("Tandem NRP"; see also 6 ), but with transfer belt and smooth roller. The relevant content of these three publications is hereby made the subject of the present description.

In the two embodiments of 3 and 4 is the first sieve 4 the first forming unit A for forming the first pulp layer AL as a wire 4.L educated. And the second forming unit B for forming the further, second pulp layer BL is arranged above the first forming unit A for forming the first pulp layer AL. The further, second pulp layer BL is therefore in the merging section 17 by means of the preferably evacuated Gautscheinrichtung 18 , in particular the preferably suctioned Gautschwalze 18.1 aufgautscht on the first fiber layer AL.

In the embodiments of the two 3 and 4 is between that in the sieve loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged Formiersaugkasten 13 and one in the sieve loop of the first sieve 4 . 4.L the first forming unit A arranged for forming the first pulp layer AL separating device 33 , preferably a curved and evacuated separating element 33.1 , in particular a roller or a stationary suction separator, a deflection device 34 , preferably a deflecting element 34.1 , in particular a guide roller, in the wire loop of the second wire 5 the first forming unit A for forming the first Fiber layer AL arranged. Due to the separator 33 becomes the second sieve 5 from the first on the first sieve 4 . 4.L located fibrous layer AL separated.

The two sieves 4 . 5 The first forming unit A for forming the first pulp layer AL with the first fibrous layer AL located between them extend after the deflection device 34 , preferably the deflecting element 34.1 , in particular the guide roller, at an angle E, preferably at an angle E of> 0 to 45 °, in particular at an angle E of 5 to 25 °, to an imaginary horizontal plane H upwards.

The two embodiments of the 3 and 4 differ in that in the embodiment of the 3 the second forming unit B for forming the further, second pulp layer BL in the wire direction S (arrow) of the first wire 4 . 4.L the first forming unit A for forming the first pulp layer AL before the merging section 17 is arranged.

The second formed by the second forming unit B and on the second sieve 19 The second forming unit B guided pulp layer BL runs into the merge section 17 at an angle D3 to that as a wire 4.1 trained first sieve 4 the first forming unit A for forming the first pulp layer AL, which is ≤ 90 °.

In the embodiment of the 4 on the other hand, the second forming unit B is for forming the further, second pulp layer BL in the direction of the wire feed S (arrow) of the first wire 4 . 4.L the first forming unit A for forming the first pulp layer AL after the merging section 17 arranged.

The second formed by the second forming unit B and on the second sieve 19 The second forming unit B guided pulp layer BL runs into the merge section 17 at an angle D4 to that as a wire 4.1 trained first sieve 4 the first forming unit A for forming the first pulp layer AL, which is ≥ 90 °.

Moreover, in the two embodiments of 3 and 4 between that in the sieve loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged Formiersaugkasten 13 and in the sieve loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged deflection 34 , preferably deflecting element 34.1 , in particular guide roller, a suction box 35 in the sieve loop of the first sieve 4 the first forming unit A for forming the first pulp layer AL arranged.

The in the 3 and 4 illustrated embodiments of a respective sheet forming device 1 with two forming units A, B are particularly suitable for use in a machine for producing a fibrous web 2 , in particular a paper, cardboard or packaging paper web of at least one pulp suspension 3 ,

A first forming unit A is preferably used for forming at least one lower fiber layer, in particular a lower back layer or a lower back layer and a middle layer, whereas a second forming unit B is used for forming an upper fiber layer, in particular an upper cover layer.

In this case, the respective sheet forming device 1 preferably downstream of a press section with at least one shoe press with a preferably double-felted press nip directly in the machine or Sieblaufrichtung. Such a press section with two shoe presses is from the documents EP 1 077 283 B1 ("Tandem NRP"; see also 6 ) and EP 1 048 780 B1 ("Tandem NRP"; see also 6 ) known. The relevant content of these two publications is hereby made the subject of the present description.

Furthermore, in the embodiments of the 1 to 4 in the respective forming zone 16 Opposite that in the sieve loop of the second sieve 5 the first forming unit A for forming the first pulp layer AL arranged Formiersaugkasten 13 and in the wire direction S (arrow) at a distance from the leading edge of the first rigid bar 15 of the Formiersaugkastens 13 at least two between each two adjacent and rigid strips 15 of the Formiersaugkastens 13 arranged formation strips 36 provided by means of known yielding elements 37 are supported and with a selectable force 37.K against the touching first sieve 4 are pressed.

As an alternative to the plurality of formation strips, in each case at least one deflector may be provided in the at least one forming zone, opposite the forming suction box and in the wire direction at a distance from the leading edge of the first rigid strip of the forming suction box.

The headbox 11.A the respective first forming unit A for forming the first pulp layer AL is also a two-layer and a headbox nozzle 38.A having headbox that in its headbox 38.A at least one protruding and preferably flexible separating element 39.A has, which is preferably designed as a flexible separating blade.

And the respective headbox 27.b The second forming unit B for forming the further, second pulp layer BL is an at least single-layered and a headbox nozzle 40.B having headbox 27.b standing in his headbox 40.B at least one preferably flexible flow lamella 41.B which in turn preferably has a fin length of ≥ 50% of the nozzle length of the headbox nozzle.

In the embodiments of the 1 to 4 indicates the respective one in the sieve loop of the first sieve 19 the second forming unit B for forming the further, second pulp layer BL arranged Impingementschuh 25.1 a shoe length 25.1L from 200 to 2,000 mm, preferably from 300 to 1,500 mm, in particular from 400 to 1,200 mm, and / or a shoe division 25.1T from 20 to 120 mm, preferably from 20 to 100 mm, in particular from 20 to 50 mm.

The two 5 and 6 show schematic side views of two known press sections 200 . 300 , which preferably in conjunction with a sheet forming device according to the invention 1 according to the 1 to 4 be used.

The in the 5 illustrated embodiment of a press section 200 in professional circles is also called DuoCentri press and is from the publication EP 1 749 926 B1 known. This one fibrous web 2 (dashed line) leading press section 200 includes a shoe press 201 with a top felted press nip 202 , The relevant content of this document is hereby made the subject of the present description.

And those in the 6 illustrated embodiment of a press section 300 in professional circles is also called Tandem NipcoFlex press and is from the pamphlets EP 1 077 283 B1 and EP 1 048 780 B1 known. This one fibrous web 2 (dashed line) leading press section 300 includes two shoe presses 301 . 302 with press nips felted on both sides 303 . 304 , The relevant content of these two publications is hereby made the subject of the present description.

In summary, it should be noted that a sheet forming apparatus of the type mentioned is further developed by the invention that a two- or multi-ply fibrous web in an optimal combination of forming units with special requirements for the single-ply ceiling layer at a basis weight of 30 to 60 g / m ² and at a speed of ≥ 1,600 m / min can be produced energy-efficiently and reliably. The special requirements for the single-ply layer of cover can concern both the raw material (fresh fiber, content of waste paper possible, higher long fiber content, bleached and unbleached) and the quality (formation, strength value, ash content on the rubber side). Furthermore, the at least one further fibrous material layer can have a basis weight of up to 150 g / m ² and a special quality focus can be on a good to very good formation, high strength values and an above-average ash content on the rubber side.

LIST OF REFERENCE NUMBERS

1

A forming apparatus

2

Fibrous web (dashed line)

3

Fibrous suspension

4

First sieve

4.L

First sieve; wire

5

Second sieve

6

forming element

6.1

forming roll

6.1d

Roll diameter

7

peripheral region

8th

vane

8.1

breast roll

9

peripheral region

10

Stock inlet gap

11.A

First headbox

12

twin

13

Formiersaugkasten

14

Formierfläche

15

Rigid bar

16

forming zone

17

Merging section

18

Gautscheinrichtung

18.1

couch roll

19

First sieve

19.L

First sieve; wire

20

Second sieve

21

vane

21.1

breast roll

22

peripheral region

23

vane

23.1

breast roll

24

peripheral region

25

forming element

25.1

Impingementschuh

25.1L

Shoe length

25.1T

Shoe division

26

Stock inlet gap

27.b

Second headbox

28

twin

29

Formiersaugkasten

30

Formierfläche

31

Rigid bar

32

forming zone

33

separator

33.1

separating element

34

deflecting

34.1

deflecting

35

suction box

36

formation bar

37

Resilient element

37.K

force

38.A

headbox

39.A

separating element

40.B

headbox

41.B

flow lamella

100

Machine for producing a two-ply fibrous web

200

Press section ("DuoCentri")

201

shoe press

202

press nip

300

Press section ("Tandem NFP")

301

First shoe press

302

Second shoe press

303

First press nip

304

Second press nip

A

First forming unit

AL

First fibrous layer

B

Second forming unit

BL

Second fibrous layer

C

angle

D1

angle

D2

angle

D3

angle

D4

angle

e

angle

H

WL

pu

vacuum

S

Sieblaufrichtung (arrow)

V

vertical plane

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0851058 A2 [0002]
• EP 0665330 A1 [0004]
• DE 102009000696 A1 [0004]
• DE 2059962 A [0005]
• EP 1749926 B1 [0057, 0075]
• EP 1077283 B1 [0057, 0068, 0076]
• EP 1048780 B1 [0057, 0068, 0076]

Claims (17)

Sheet forming device ( 1 ) for a machine ( 100 ) for producing a two- or multi-ply fibrous web, in particular a paper, board or packaging paper web from at least two pulp suspensions ( 3 ), comprising a first forming unit (A) for forming at least one fibrous layer (AL) with two continuous endless sieves ( 4 . 5 ; 4 . 4.L . 5 ), of which the first sieve ( 4 ; 4 . 4.L ) over a peripheral region of a forming element ( 6 ), in particular a forming roller ( 6.1 ) and the second sieve ( 5 ) over a peripheral area ( 9 ) of a guiding element ( 8th ), in particular a breast roll ( 8.1 ) and then in the region of the forming element ( 6 ), in particular the forming roller ( 6.1 ) on the first sieve ( 4 . 4 . 4.L ) to form a wedge-shaped material inlet gap ( 10 ) directly from a first headbox ( 11.A ) the at least one pulp suspension ( 3 ), runs up, the two sieves ( 4 . 5 ; 4 . 4.L . 5 ) with the at least one fibrous layer (AL) located between them in the direction of the wire feed (S), then at least in sections a double-wire zone ( 12 ), wherein in the region of the twin-wire zone ( 12 ) and each other of the forming element ( 6 ), in particular the forming roller ( 6.1 ) a Formiersaugkasten ( 13 ) with a preferably curved forming surface ( 14 ), which consists of a plurality of mutually spaced and rigid strips ( 15 ), over which the two sieves ( 4 . 5 ; 4 . 4.L . 5 ) are guided with the at least one fibrous layer (AL) located between them, and in the direction of the wire (S) at least one with a preferably controllable negative pressure (pu) acted upon forming ( 16 ), a second forming unit (B) for forming at least one further pulp layer (BL) with at least one continuous endless screen ( 19 ), and a merging section ( 17 ), in which the at least two fiber layers (AL, BL) after each one-sided removal of a sieve ( 4 . 20 ; 5 ; 20 ; 5 . 20 ; 5 . 20 ) to form the two- or multi-ply fibrous web ( 3 ) and a preferably evacuated Gautscheinrichtung ( 18 ), in particular a preferably evacuated Gautschwalze ( 18.1 ), characterized in that the second forming unit (B) for forming at least one further pulp layer (BL) at least two screens ( 19 . 20 ), each over a peripheral area ( 22 . 24 ) of a guiding element ( 21 . 23 ), in particular a breast roll ( 21.1 . 23.1 ), which are then in the region of a forming element ( 25 ), in particular a rigid, curved and suctioned impingement shoe ( 25.1 ) to form a wedge-shaped material inlet gap ( 26 ) directly from a second headbox ( 27.b ) the at least one pulp suspension ( 3 ) and converge, and the at least one fibrous layer (BL) between them in the direction of wire stretching (S) then at least in sections a double-wire zone (FIG. 28 ), wherein in the region of the twin-wire zone ( 28 ) and each other of the forming element ( 25 ), in particular the impingement shoe ( 25.1 ) a Formiersaugkasten ( 29 ) with a preferably curved forming surface ( 30 ), which consists of a plurality of mutually spaced and rigid strips ( 31 ), over which the two sieves ( 19 . 20 ) are guided with the at least one fibrous layer (BL) located between them and in the direction of the screen direction (S) at least one forming zone which can be acted upon by a preferably controllable negative pressure (pu) ( 32 ) trains. Sheet forming device ( 1 ) according to claim 1, characterized in that the two sieves ( 4 . 5 ; 4 . 4.L . 5 ) of the first forming unit (A) for forming at least one fibrous layer (AL) with the at least one fibrous layer (AL) located between them in a forming element (A) 6 ), in particular the forming roller ( 6.1 ) in Sieblaufrichtung (S) downstream region of the twin-wire zone ( 12 ) at an angle (C) of 10 to 50 °, preferably from 20 to 40 °, in particular from 25 to 35 °, to an imaginary vertical plane (V) run down. Sheet forming device ( 1 ) according to claim 1 or 2, characterized in that between that in the wire loop of the second wire ( 5 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged Formiersaugkasten ( 13 ) and in the sieve loop of the second or first sieve ( 5 ; 4 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged Gautscheinrichtung ( 18 ), in particular Gautschwalze ( 18.1 ) a separating device ( 33 ), preferably a curved and evacuated separating element ( 33.1 ), in particular a roller or a stationary vacuum cleaner, in the wire loop of the second or first sieve ( 5 ; 4 ) of the first forming unit (A) for forming at least one fibrous layer (AL) is arranged, wherein in this case the first or second sieve ( 4 ; 5 ) of the at least one on the second or first ( 5 ; 4 ) Located fiber fabric layer (AL) is separated. Sheet forming device ( 1 ) according to claim 3, characterized in that the first sieve ( 4 ) of the second forming unit (B) for forming at least one further pulp layer (BL) as a wire ( 4.1 ) is formed such that the first forming unit (A) for forming at least one fibrous material layer (AL) above and in the wire-width direction (S) of the first sieve (A) 4 ) of the second forming unit (B) for forming at least one further pulp layer (BL) before or after the merging section ( 17 ) is arranged and that the at least one formed by means of the first forming unit (A) and on the second or first sieve ( 5 ; 4 ) of the first forming unit (A) guided fiber layer (AL) in the merge section ( 17 ) at an angle (D1) to that as a wire ( 4.1 ) formed first sieve ( 4 ) of the second forming unit (B) for forming at least one further pulp layer (BL) enters, which is ≤ 90 °, preferably ≤ 75 °, in particular ≤ 60 °, or ≥ 90 °, preferably 105 °, in particular ≥ 120 °. Sheet forming device ( 1 ) according to claim 1 or 2, characterized in that between that in the wire loop of the second wire ( 5 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged Formiersaugkasten ( 13 ) and one in the sieve loop of the first sieve ( 4 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged separating device ( 33 ), preferably a curved and evacuated separating element ( 33.1 ), in particular a roller or a stationary separating sucker, whereby the second sieve ( 5 ) of the at least one on the first sieve ( 4 ) pulp layer (AL) is separated, a deflection device ( 34 ), preferably a deflecting element ( 34.1 ), in particular a deflection roller, in the screen loop of the second screen ( 5 ) of the first forming unit (A) for forming at least one fibrous layer (AL) is arranged. Sheet forming device ( 1 ) according to claim 5, characterized in that the first sieve ( 4 ) of the first forming unit (A) for forming at least one fibrous layer (AL) as a wire ( 4.1 ) and that the second forming unit (B) for forming at least one further pulp layer (BL) above the first sieve ( 4 ) of the first forming unit (A) for forming at least one fibrous layer (AL) is arranged. Sheet forming device ( 1 ) according to claim 5 or 6, characterized in that between the in the wire loop of the second sieve ( 5 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged Formiersaugkasten ( 13 ) and in the sieve loop of the second sieve ( 5 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged deflecting device ( 34 ), preferably deflecting element ( 34.1 ), in particular deflection roller, at least one suction box ( 35 ) in the sieve loop of the first sieve ( 4 ) of the first forming unit (A) for forming at least one fibrous layer (AL) is arranged. Sheet forming device ( 1 ) according to the preceding claims, characterized in that in the at least one forming zone ( 16 ), opposite that in the sieve loop of the second sieve ( 5 ) of the first forming unit (A) for forming at least one pulp layer (AL) arranged Formiersaugkasten ( 13 ) and in the wire direction (S) at a distance from the leading edge of the first rigid strip ( 15 ) of the Formiersaugkastens ( 13 ) at least two between each two adjacent and rigid strips ( 15 ) of the Formiersaugkastens ( 13 ) arranged formation bars ( 36 ) provided by means of compliant elements ( 37 ) are supported and with a selectable force ( 37.K ) against the first sieve touching it ( 4 ) are pressed. Sheet forming device ( 1 ) according to the preceding claims, characterized in that the head box of the first forming unit (A) for forming at least one pulp layer (AL), an at least two-layered and a headbox nozzle ( 38.A ) headbox ( 11.A ) located in the headbox nozzle ( 38.A ) at least one protruding and preferably flexible separating element ( 39.A ), which is preferably designed as a flexible separating blade. Sheet forming device ( 1 ) according to the preceding claims, characterized in that in the wire loop of the first sieve ( 19 ) of the second forming unit (B) for forming at least one further pulp layer (BL) arranged Impingementschuh ( 25.1 ) a shoe length ( 25.1L ) from 200 to 2,000 mm, preferably from 300 to 1,500 mm, in particular from 400 to 1,200 mm, and / or a shoe division ( 25.1T ) of from 20 to 120 mm, preferably from 20 to 100 mm, in particular from 20 to 50 mm. Sheet forming device ( 1 ) according to the preceding claims, characterized in that in the at least one forming zone ( 32 ), opposite that in the sieve loop of the second sieve ( 20 ) of the second forming unit (B) for forming at least one further pulp layer (BL) arranged Formiersaugkasten ( 29 ) and in the wire direction (S) at a distance from the leading edge of the first rigid strip ( 31 ) of the Formiersaugkastens ( 29 ) at least two between each two adjacent and rigid strips ( 31 ) of the Formiersaugkastens ( 29 ) arranged formation bars ( 36 ) provided by means of compliant elements ( 37 ) are supported and with a selectable force ( 37.K ) against the first sieve touching it ( 19 ) are pressed. Sheet forming device ( 1 ) according to the preceding claims, characterized in that the headbox of the second forming unit (B) for forming at least one further pulp layer (BL) is an at least single-layered and a headbox nozzle (B). 40.B ) headbox ( 27.b ), which in its headbox ( 40.B ) at least one preferably flexible flow blade ( 41.B ), which preferably in turn a Lamella length of ≥ 50% of the nozzle length of the headbox has. Sheet forming device ( 1 ) according to the preceding claims, characterized in that in the wire direction (S) after the at least one forming zone ( 16 . 32 ) a separating device ( 33 ), preferably a curved and evacuated separating element ( 33.1 ), in particular a roller or a stationary suction separator is arranged, in which case the other sieve ( 4 . 20 ; 5 ; 20 ; 4 . 20 ; 5 . 20 ) of the at least one on the one sieve ( 5 . 19 ; 4 . 19 ; 5 . 19 ; 4 . 19 ) pulp layer (AL, BL) is separated. Machine ( 100 ) for producing a two- or multi-ply fibrous web ( 2 ), in particular a paper, board or packaging paper web of at least one pulp suspension ( 3 ), characterized in that it comprises at least one sheet forming device ( 1 ) according to one of the preceding claims. Machine ( 100 ) according to claim 14, characterized in that the sheet forming device ( 1 ) preferably directly in the machine or Sieblaufrichtung (S) a press section ( 200 ; 300 ) with at least one shoe press ( 201 ; 301 . 302 ) is subordinate. Machine ( 100 ) according to claim 15, characterized in that the sheet forming device ( 1 ) has two forming units (A, B) for respectively forming at least one pulp layer (AL, BL), wherein the one forming unit (B) for forming a lower pulp layer (BL), in particular a lower cover layer at least according to one of claims 10 to 13 is formed and wherein the other forming unit (A) is designed to form at least one further fibrous material layer (AL), in particular an upper backsheet and at least one central layer according to at least one of claims 2 to 9, and that the press section (FIG. 200 ) at least one shoe press ( 201 ) with a top-felted press nip ( 202 ) having. Machine ( 100 ) according to claim 15, characterized in that the sheet forming device ( 1 ) has two forming units (A, B) for respectively forming at least one fibrous layer (AL, BL), wherein the one forming unit (A) for forming at least one lower fibrous layer (AL), in particular a lower backsheet or a lower backsheet and a middle layer at least according to one of claims 2 to 9, and wherein the other forming unit (B) is designed to form an upper pulp layer (BL), in particular an upper cover layer according to at least one of claims 10 to 13, and in that the press section ( 300 ) at least one shoe press ( 301 . 302 ) having.

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