DE102017111869A1 - Apparatus and method for producing a fibrous web - Google Patents

Abstract

The invention relates to a device (1) for producing a multilayer fibrous web (2), comprising a wire section (3) for forming the multilayer fibrous web (2), a press section (11) for further dewatering the multilayer fibrous web (2) and a dryer section ( 37) for drying the multi-ply fibrous web (2), wherein the wire section (3) comprises a first air-permeable forming belt (4) arranged to form a first ply (2a) of the multi-ply fibrous web (2) and which comprises the formed multi-ply fibrous web (2) to a take-off point (7) with a removal device (8), wherein the removal device (8) comprises a Abnahmesaugelement (9) and this another wrap around band (10) and the multilayer fibrous web (2) by the removal device (8 ) is removed at the take-off point (7) from the first air-permeable forming belt (4) and the press section (11) comprises at least three press nips (12, 13, 14), wherein the two last n press nips (13, 14) by a third pressing element (17) and a second pressing element (16) and a common counter element (18) with a smooth surface for smoothing the side of the first layer which is in direct contact with the first air-permeable forming belt (4) (2a) of the multilayer fibrous web (2), and the first press nip (12) is formed by the second pressing element (16) of the second press nip (13) and a first pressing element (15). According to the invention, it is provided that the first press nip (12) is double-felted and has an upper felt (20) and an under felt (21) and that the further band (10) is designed as an air-permeable transfer belt (10) and forms a transfer zone (22) extends from the take-off point (7) to a transfer point (23) of the fibrous web (2) to the lower felt (21) of the first press nip (12).

Description

The invention relates to a device for producing a multilayer fibrous web, with a wire section for forming the multilayer fibrous web, a press section for further dewatering of the multilayer fibrous web and a drying section for drying the multilayer fibrous web, wherein the wire section a first air-permeable Formierband, to form a first Layer of the multi-ply fibrous web is set up comprises and which leads the formed multi-ply fibrous web to a take-off point with a pick-up device, the pick-up a Abnahmesaugelement and a further encompassing this further band comprises and the multi-layer fibrous web is removed by the removal device at the take-off point of the first air-permeable Formierband and the press section comprises at least three press nips, wherein the last two press nips by a third pressing member and a second pressing member and a common counter element with smooth surface for smoothing the first air-permeable Formierband in direct contact side of the first layer of the multilayer fibrous web, are formed and the first press nip formed by the second pressing member of the second press nip and a first pressing member.

The invention also relates to a method for producing a multilayer fibrous web.

Devices of this type are known from the prior art. The document DE102014210879 A1 describes a paper machine and a method for producing packaging papers. A multi-layer packaging paper web, consisting of a cover, a protective layer and a supine position, is produced in a wire section with two forming units and in a press section, consisting of a compact press with 3 Pressnips, further dewatered and then fed to a dryer section and further process steps. In the wire section, the supine is puffed onto the coverage and dewatered through the coverage. This leads to a graying of the usually bright coverage.

The document DE 11 2009002741T5 also discloses a machine for producing a multi-ply board web, for example a white top liner with a cover and a backsheet. The individual layers are formed in the wire section, interconnected, dewatered and transferred with a press felt in the press section, which can be designed as a compact press with three press nips.

Another machine for producing cardboard with at least two layers is in the document DE 60027739 T2 described. The wire section consists of two forming units for producing a cover and a supine position with subsequent Vergautschung to a board web. This is then transferred by a press belt in the press section and further dehydrated. This consists of a compact press with three press nips. This is followed by a drying section and further process sections. In the wire section, the supine is puffed onto the coverage and dewatered through the coverage. This leads, as already stated, to a graying of the usually bright coverage.

The known devices either have the disadvantage of graying the high-quality bright coverage, which leads to an impairment, or the paper machine configurations are very complex and expensive. In the DE 60027739 T2 is in one embodiment of the ( 3 ) the cover layer in the wire section at the top to avoid drainage of the supine position by the coverage. However, this requires an elaborate press-section configuration in the form of an inverted compact press with poor runnability or an additional fourth press for smoothing the surface of the cover.

The object of the invention is therefore to propose an apparatus for producing a multilayer fibrous web, for example a white top liner or white top test liner, which on the one hand ensures good runnability of the fibrous web in the paper machine and, on the other hand, the deterioration in quality, such as graying and low Smoothness counteracts the higher-grade position of the multilayer fibrous web, for example the light coverage.

The object is solved by features of claim 1. The invention relates to a device for producing a multilayer fibrous web for a paper machine, comprising a wire section for forming the multilayer fibrous web, a press section for further dewatering the multilayer fibrous web and a dryer section for drying the multilayer fibrous web, the wire section comprising a first air-permeable forming belt, which is arranged to form a first layer of the multi-ply fibrous web, and which guides the formed multi-ply fibrous web to a take-off point with a take-off device, the take-off device comprising a take-off suction element and a further belt wrapping around it and the multilayer fibrous web being passed through the take-off device at the take-off point of first air-permeable forming belt is removed and the press section comprising at least three press nips, wherein the two last press nips are formed by a third pressing element and a second pressing element and a common smooth surface counter element for smoothing the side of the first layer of the multilayer fibrous web which is in direct contact with the first air permeable forming belt and the first Press nip is formed by the second pressing member of the second press nip and a first pressing member.

According to the invention, it is provided that the first press nip is double-felted and has an upper felt and a lower felt and that the further band is designed as an air-permeable transfer belt and forms a transfer zone from the take-off point to a transfer point of the fibrous web to the lower felt of the first press nip extends.

This device has the advantage that the first layer of the multilayer fibrous web formed on the first forming belt is dewatered in combination with a simple press configuration, and the side facing the first forming belt is smoothed in the press. The double-felted first press nip increases the dewatering capacity of the press section. This arrangement is advantageously suitable for the production of white top liners or white top test liners. These types of boxes and packaging papers include a higher-quality, lighter-colored coverage and a darker, usually brown supine. Depending on the type of cardboard, additional layers may be provided between these layers. As a liner, for example, a protective layer and a deposit are common. The present invention is thus particularly advantageously applicable to the production of white top liners or white top test liners, wherein the first layer is formed by the coverage.

In a further practical embodiment, a transfer suction element, preferably a suction box, with at least one suction zone in the region of the transfer zone is arranged in the loop formed by the transfer belt. The multi-ply fibrous web is further dewatered through the at least one suction zone, the dewatering direction now extending in the opposite direction to the dewatering direction on the first forming belt. This type of further dewatering allows the dewatering on the first forming belt to be reduced, for example by lower dewatering pressures, without reducing the dry content of the multi-ply fibrous web at the entry to the press section. A graying of the first layer is thus counteracted. As a result of this displacement of the dewatering into the transfer zone, the marking of the side to be smoothed of the first layer of the multilayer fibrous web also decreases through the forming belt. An improvement in the smoothness of the first layer is achieved.

Advantageously, the transfer suction on at least two, preferably at least three, suction zones in the direction of manufacture. This allows the drainage process to be adjusted.

In a practical case, the negative pressure in the at least one suction zone can be set to a value of more than 20 kPa, in particular more than 30 kPa, preferably more than 40 kPa.

In a further embodiment, the transfer suction element has at least two suction zones in the production direction and wherein the negative pressure in the suction zones can be increased in the direction of production.

Furthermore, it is advantageous for the transfer suction element to have a water-permeable ceramic coating facing the transfer belt.

Preferably, the ceramic covering comprises strips and slots and wherein the width of the slots in the direction of manufacture is preferably greater than 10 mm. The slots between the strips extend over the entire width of the transfer suction. However, it is also possible that the slots are interrupted transversely to the direction of manufacture by webs.

In one possible embodiment, the ceramic covering is at least partially perforated.

Further, the ceramic coating may also include a combination of ledges and slots and perforations. The perforations can be designed as holes.

The relative open area of the ceramic coating is preferably greater than 50%.

In a practical embodiment, the Abzugsesaugelement is designed as a suction roll or as a tube suction or as a flat vacuum. In particular, at speeds of the paper machine of greater than 700 m / min, a suction roll is particularly suitable.

The decrease suction element is preferably operable with a negative pressure of more than 20 kPa, in particular more than 30 kPa, preferably more than 40 kPa.

In a possible practical case, the Abzugsesaugelement is designed as a suction roller with two successively arranged in the direction of manufacture suction zones. The first suction zone is as Decrease suction zone and the second suction zone is designed as a holding zone such that negative pressures of more than 20 kPa, in particular more than 30 kPa can be applied. It is particularly advantageous if the intake suction is carried out so that the negative pressure of the second suction zone, that is, the holding zone, higher than the negative pressure of the first suction zone, ie the take-off zone is. The decrease suction element thus differs from known Abnahmesaugelementen in which the negative pressure of the second suction zone, that is, the holding zone, smaller than the negative pressure of the first suction zone, ie the take-off zone, is. After the holding zone, the transfer suction follows, wherein the multi-layer fibrous web is held by the negative pressure of the at least one suction zone of the transfer suction on the transfer belt.

In a further embodiment variant, the Abzugsesaugelement is designed as a suction roller and the suction roller is assigned a groove functionally, which is preferably integrated into the suction element of the transfer suction. The gutter absorbs the water thrown off by the suction roll. The water is discharged laterally transversely to the production direction, preferably together with the water of the at least one suction zone of the transfer suction element.

In an advantageous embodiment, the air permeability of the transfer belt is greater, in particular at least twice as large, as the air permeability of the first Formierbandes. This achieves a high dry content of the multilayer fibrous web and at the same time stabilizes the drainage.

Before the take-off point, preferably a steam blowing device for direct loading of the multilayer fibrous web with steam is arranged. The steam blower extends over the entire width of the fibrous web.

In a practical case, in the region of the transfer zone, a steam blowing device for direct loading of the multilayer fibrous web with steam is arranged. The steam blower extends over the entire width of the fibrous web.

Advantageously, the Formierband is designed as a mesh or as an air-permeable membrane. For example, the Formierband is designed as a woven Formiersieb or perforated air-permeable membrane.

The transfer belt can be designed as a sieve cloth or as an air-permeable membrane or as a spiral sieve. For example, the transfer belt is designed as a woven forming fabric or as a perforated air-permeable membrane.

The underfelt may be assigned to stabilize the web run between the transfer point and the first press nip on the side facing away from the fibrous web a web stabilizer.

In a practical advantageous embodiment, the transfer belt is free of a press nip. By press nip is meant, for example, a press nip formed by two rolls. Due to the fact that the transfer belt together with the multilayer fibrous web is not guided by a press nip, marking or structuring of the side to be smoothed is avoided.

In an exemplary embodiment, the wire section comprises at least a first forming unit with the first forming belt for forming the first layer of the multi-ply fibrous web and at least one second forming unit for forming a second layer of the multilayer fibrous web and a Vergautschungszone. The forming units are arranged and configured with respect to one another in such a way that the second layer of the multilayer fibrous web onto which the first layer of the multilayer fibrous web in the lining zone is formed to form the multilayer fibrous web.

Preferably, substantially no dehydration takes place in the region from the glazing zone to the take-off point of the fibrous web. This area is preferably free of drainage elements for dewatering the fibrous web in the direction of the first forming belt.

Optionally, in this area, suctioned devices may be provided on the side of the first forming belt opposite the fibrous web only for the purpose of stabilizing the web run.

Advantageously, the multilayer fibrous web may comprise white-covered liners, in particular white top testliner with a cover layer and a backsheet, and the wire section be set up in such a way that the cover layer forms the first layer of the multilayer fibrous web.

The wire section may additionally comprise forming units for forming further layers, such as a protective layer or an insert.

It is also possible to form at least one further layer through a multi-layer headbox in combination with the forming unit for the cover layer or with the forming unit for the supine position. The multi-layer headbox brings two layers consisting of different Pulp suspensions on the appropriate Formierband on.

In a practical embodiment, the common counter element of the second and the third press nip is designed as a smooth-surfaced roll for smoothing the underside of the first layer of the fibrous web.

In one possible embodiment, the common counter element of the second and the third press nip is designed as a roller with a smoothly smoothing surface, preferably impermeable to air, for smoothing the underside of the first layer of the fibrous web.

The course of the air-permeable transfer belt may preferably be selected such that the direction of the transfer zone, that is to say the running direction of the transfer belt in the region of the transfer zone, lies substantially between an imaginary horizontal line, that is to say the production direction, and an imaginary vertical line. It is also conceivable to select the direction of the transfer zone such that the running direction of the transfer belt in the region of the transfer zone has a direction component counter to the direction of production.

Preferably, the transfer belt runs in the transfer zone after the Abnahmesaugelement at an angle between 0 ° to 120 °, in particular between 20 ° to 120 ° inclined to the direction of manufacture. That is, the transfer zone is oriented at an angle of 0 ° to 120 °.

Particularly advantageous is a possible orientation of the transfer zone in an angular range between 40 ° to 90 °. As a result, the removal of, by the taking place in the transfer zone dewatering of the multilayer fibrous web, resulting white water is improved and facilitated. The dewatered white water is dissipated by its kinetic energy. Depending on the orientation of the transfer zone, no vacuum support is required for the removal. In particular, for angles of inclination between 20 ° and 90 °, the white water can flow out of the separate transfer suction without the use of additional energy.

Advantageous is a possible orientation of the transfer zone in an angular range between 80 ° to 120 °, in particular between 90 ° and 120 °. As a result, the removal of, by the taking place in the transfer zone dewatering of the multilayer fibrous web, resulting white water is improved and facilitated. The dewatered white water is dissipated by its kinetic energy and by the action of gravity. A vacuum support for the discharge is not necessary in this case.

The inclined arrangement of the transfer zone to the production direction can be counteracted by a possible uncontrolled rewetting of the multilayer fibrous web.

In one possible embodiment, the transfer suction element can be formed by a plurality of separate transfer suction elements, which can be designed, for example, in each case as a suction box. For example, two to four suction boxes can be arranged one behind the other in the region of the transfer zone. The sides of the separate transfer suction elements facing the transfer belt can be provided with an open, water-permeable ceramic covering. The separate transfer suction can be sucked each to increase the drainage, wherein the respective negative pressure in the separate transfer suction adjustable, preferably independently adjustable.

In a preferred practical embodiment, the plurality of separate transfer suction elements each have a collecting channel for collecting and removing the white water. The collecting channel extends transversely to the direction of manufacture and may have one or more connections for discharging the white water.

In a practical case, the negative pressure in at least one of the several separate transfer suction is adjustable to a value of more than 20 kPa, in particular more than 30kPa, preferably more than 40kPa.

In a further embodiment, the negative pressure in the several separate transfer suction in the direction of the transfer belt is increasing.

In particular, for a transfer zone inclined to the horizontal, it may be advantageous to lower the take-off point and thus also the transfer point. As a result, the height of the subsequent press section is reduced or counteracted an increase in the height of the press as a result of a horizontal inclined to the transfer zone.

Preferably, the removal point is located on a lying below the loop formed by the first forming belt horizontal plane.

The object is also solved by the features of claim 23.

It is proposed a method for producing a multilayer fibrous web, which is formed in a wire section, further dewatered in a press section and dried in a dryer section, wherein in the wire section a first layer of the multilayer fibrous web on a first air-permeable Formierband is formed and the formed multi-layer fibrous web is passed through the first air-permeable Formierband to a delivery point with a pickup device, wherein the removal device comprises a Abnahmesaugelement and a further band wrapped around this and the multilayer fibrous web through the removal device at the take-off point of the first air-permeable Formierband by the further strip is removed and fed to the press section with at least three press nips, the last two press nips being formed by a third pressing element and a second pressing element and a common counter-element having a smooth surface, and wherein the side in direct contact with the first air-permeable forming belt the first layer of the multilayer fibrous web is brought into direct contact with the common counter element and smoothed, and wherein the first press nip through the second pressing element of the second n Pressnips and a first pressing member is formed. According to the invention, the method is characterized in that the first press nip is double-felted and has an upper felt and a lower felt and that the further band is designed as an air-permeable transfer belt and that transfer the multi-ply fibrous web at a transfer point from the transfer belt to the lower felt of the first press nip becomes.

The invention expressly extends to such embodiments, which are not given by combinations of features of explicit back references of the claims, whereby the disclosed features of the invention - as far as is technically feasible - can be combined with each other.

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

• 1 eine Ausführungsform einer erfindungsgemäßen Vorrichtung mit einem Transferband zwischen der Siebpartie und der Pressenpartie vereinfachter Darstellung;
• 2 eine Ausführungsform einer erfindungsgemäßen Vorrichtung mit einer beispielhaften Siebpartieausführung vereinfachter Darstellung;
• 2a eine Variante der Pressenpartie der erfindungsgemäßen Vorrichtung in vereinfachter Darstellung;
• 3 eine zweite Variante einer Siebpartieausführung der erfindungsgemäßen Vorrichtung vereinfachter Darstellung;
• 3a ; eine dritte Variante einer Siebpartieausführung der erfindungsgemäßen Vorrichtung vereinfachter Darstellung;
• 3b eine weitere Variante einer Siebpartieausführung der erfindungsgemäßen Vorrichtung vereinfachter Darstellung;
• 4 einen Ausschnitt mit einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung mit einem vertikalen Verlauf der Transferzone in vereinfachter Darstellung;
• 5 einen Ausschnitt mit einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung mit einer tiefergelegten Abnahmestelle in vereinfachter Darstellung;

Show it

• 1 an embodiment of a device according to the invention with a transfer belt between the wire section and the press section simplified representation;
• 2 an embodiment of a device according to the invention with an exemplary Siebpartieausführung simplified representation;
• 2a a variant of the press section of the device according to the invention in a simplified representation;
• 3 a second variant of a Siebpartieausführung the device of the invention simplified representation;
• 3a ; a third variant of a Siebpartieausführung the device of the invention simplified representation;
• 3b a further variant of a Siebpartieausführung the device of the invention simplified representation;
• 4 a section with a further embodiment of the device according to the invention with a vertical course of the transfer zone in a simplified representation;
• 5 a section with a further embodiment of the device according to the invention with a lowered collection point in a simplified representation;

In 1 is an embodiment of a device according to the invention 1 for producing a multilayer fibrous web 2 for a paper machine, with a wire section 3 to form the multilayer fibrous web 2 , with a press section 11 for further dewatering of the multilayer fibrous web 2 and with a dryer section 37 for drying the multilayer fibrous web 2 shown. Between the wire section 3 and the press section 11 is an air-permeable transfer belt 10 for guiding the multilayer fibrous web 2 from the wire section 3 to the press section 11 arranged. The transfer zone 22 is essentially aligned horizontally. That is the course of the transfer belt 10 in the area of the transfer zone 22 after the decrease suction 9 is horizontal. The wire section 3 has a first air permeable forming belt 4 on, to form a first layer of the multilayer fibrous web 2 is set up. By means of a removal device 8th passing through the transfer belt 10 and a decrease suction 9 is formed, the multi-layer fibrous web 2 that is, the first layer with at least one other layer from the first forming belt 4 at a delivery point 7 taken off while on the transfer belt 10 transmitted (known as the pick-up post). Before the delivery point 7 is the first band 4 via a sieve deflecting roller 34 guided. The transfer band 10 wraps around the intake suction 9 , which in this example as a suction roll 9 is executed, wherein the applied negative pressure is greater than 20kPa. The first band 4 runs after the delivery point 7 via a guide roller 35 and over guide rollers 39 back again. The guide rolls 39 are arranged on a zigzag-shaped line about a substantially horizontally oriented line so that the first forming belt is returned substantially horizontally. The air-permeable transfer belt 10 extends to form a transfer zone 22 from the delivery point 7 to a transfer point 23 at the fibrous web 2 to the underfelt 21 of the first press nip 12 is handed over. In the area of the delivery point 7 and the transfer point 23 is the multi-layer fibrous web 2 always supported. These transfer points are thus carried out without free train. Inside through the transfer belt 10 The loop formed in this example is a suction box 24 as transfer suction element 24 used. The suction box 24 has three suction zones 25 . 26 . 27 and is in the area of the transfer zone 22 arranged. The negative pressure in the suction zones is more than 20kPa. The vacuum supply and / or the suction box 24 are formed such that the negative pressure is increasing from suction zone to suction zone adjustable. So the first suction zone 25 a negative pressure of more than 20kPa, the second suction zone 26 a negative pressure of more than 30kPa and the third suction zone 27 have a negative pressure of more than 40kPa. Through the suction zones, the multilayer fibrous web is further dewatered, wherein the dewatering direction now in the opposite direction to the direction of dewatering on the first Formierband 4 runs. This allows drainage on the first forming belt 4 reduce, for example, by lower dewatering pressures, without the dry content of the multilayer fibrous web 2 at the entrance to the press section. A graying of the first layer is thus counteracted. By this shift of drainage into the transfer zone 22 Also takes the mark through the first forming belt 4 the side of the first layer to be smoothed 2a the multilayer fibrous web 2 from. An improvement in the smoothness of the first layer 2a is achieved. At the transfer suction element 24 is, seen in the direction of manufacture, before the first suction zone 25 one of the suction roll 9 associated gutter 28 arranged for discharging the thrown off white water and preferably integrated in the transfer suction. The transfer suction element 24 has a transfer belt 10 facing water-permeable ceramic coating on. The ceramic coating is made with strips and with intermediate slots with a slot width of 12 mm.

The press section 11 consists of three pressnips 12 . 13 . 14 , with the last two pressnips 13 . 14 by a third pressing element 17 and a second pressing element 16 and a common counter element 18 with a smooth surface for smoothing the first air-permeable forming belt 4 in direct contact side of the first layer 2a the multilayer fibrous web 2 , are formed and the first press nip 12 through the second pressing element 16 of the second press nip 13 and a first pressing element 15 is formed. The third pressing element 17 of the third press nip 14 is designed as a shoe roll to form an extended press nips. However, it is also conceivable to provide a press nip formed by two press rolls at this point. The common counter element 18 is designed as a roller with a smooth cover or a smooth coating. The first press nip 12 is double felted and has an upper felt 20 and an underfelt 21 on. The second pressing element 16 is designed as a suction press roll and promotes both the drainage of the multilayer fibrous web 2 , as well as their runnability, that is the running behavior of the fibrous web 2 , After passing through the three press nips 12 . 13 . 14 enters the fibrous web 2 over a free train to the drying wire of the dryer section 37 , At least the first dryer section of the dryer section 37 is designed as a single-row dryer section. In the 1 only the first drying cylinder and the following suction roll is shown. At the counter element 18 is a scraper 33 intended to keep the smooth surface clean.

In the production direction 38 Seen, is in front of the delivery point 7 a Saugumlenkwalze 34 for deflecting the first Formierbandes 4 arranged. To improve drainability of the multilayer fibrous web 2 is in front of the Saugumlenkwalze 34 a steam blower 29 intended. Likewise, in the area of the transfer zone 22 a steam blower 30 be installed. To improve the runnability of the multilayer fibrous web 2 is in the area of the underfelt 21 before the first press nip12 in through the underfelt 21 formed loop a web stabilizer 31 intended. In the area of the first forming band 4 , in the area of the transfer zone 22 and after the first press nip 14 can edge cutters 32 for trimming both sides of the multilayer fibrous web 2 be provided. The separated edge strips are thus after the take-off point 7 from the first forming belt 4 and / or in the region of the counter element 18 from the remaining fibrous web 2 led away and removed. The delivery point 7 is subordinate within that of the first Formierbandes 4 formed loop a deflection roller 35 provided for opening and closing the gap between the transfer belt 10 and the first forming belt 4 is designed to swivel. Thus, it is possible the delivery point 7 for example, in a Bahnabrisssituation to open and close.

In the 2 an embodiment of a device according to the invention with an exemplary Siebpartieausführung shown in a simplified representation. The first band 4 is designed as a wire and forms the first forming unit 3a on which the first location 2a the multilayer fibrous web 2 is formed. The first band 4 is a headbox 36 assigned to the application of a pulp suspension. This is dewatered by means of known drainage elements through the first Formierband through and thus the first layer 2a educated. This wire section 3 has one above the first forming unit 3a arranged second forming unit 3b on which a second layer 2 B the multilayer fibrous web 2 forms. The second location 2 B the multilayered Fibrous web 2 is using a gas roller 6 in a glazing zone 5 on the first location 2a aufgegautscht and thus the multi-layer fibrous web 2 educated. In the case of a two-ply fibrous web 2 the second layer is popped up directly onto the first layer. In the case of a three- or four-ply fibrous web with one or two intermediate layers, the second layer is puffed onto one of the intermediate layers. Three- or four-ply fibrous webs can be produced by additional forming units and / or by multi-layer casseroles in combination with the described wire section. The second forming unit 3b is designed as a twin-wire former. The one of a headbox 36 output pulp suspension is between two Formierbändern to form the second layer 2 B dewatered. With regard to the description of the other, provided with reference numerals, elements is on the description of 1 directed. Corresponding elements are identified by the same reference numerals.

In the 2a is a variant of the press section of the device according to the invention according to the 1 and 2 shown. The common counter element 18 of the second and third press nips 13 . 14 is as a roller with a this wrap around, preferably impermeable smoothing belt 19 with smooth surface, for smoothing the bottom of the first layer 2a the fibrous web 2 , executed. The multi-layer fibrous web 2 is from the dryer fabric of the subsequent drying section directly from the smoothing belt 19 removed without free pull.

In the 3 . 3a and 3b Further variants of a Siebpartieausführung the device according to the invention are shown in a simplified representation. In the 3 is above that through the first forming belt 4 formed first forming unit 3a a second forming unit 3b arranged. This is also designed as a four-wire. In addition, the wire is another forming fabric for dewatering the second layer on both sides 2 B assigned. The 3a is different from the one in the 3 illustrated wire section 3 by a sectioned two-sided drainage of the first layer 2a before the plating zone 5 , The first band 4 is assigned an upper sieve for dewatering the fibrous web upwards. The first forming unit 3a is thus designed as a hybrid former. In the in 3b illustrated wire section 3 becomes the first location 2a the multilayer fibrous web 2 in a first forming unit designed as a twin-wire former 3a drained after two sides. The first forming unit 3a is thus designed as Gapformer. In all three variants of the wire section is the multi-layer fibrous web 2 through the first forming belt 4 until acceptance by the transfer belt 10 at the delivery point 7 guided. From the Vergautschungszone 5 to the delivery point 7 There is essentially no drainage anymore. With regard to the description of the other, provided with reference numerals, elements, reference is made to the description of the preceding figures. Corresponding elements are identified by the same reference numerals.

The 4 shows a section with a further embodiment of the device according to the invention 1 with a vertical, that is, at an angle 40 from 90 ° to the direction of production arranged course of the transfer zone 22 in a simplified representation. This possible embodiment is an alternative to the embodiment shown in the preceding figures with a horizontal course of the transfer zone 22 , The multi-layer fibrous web 2 is by means of a removal device 8th passing through the transfer belt 10 and a decrease suction 9 is formed, from the first Formierband 4 at a delivery point 7 taken off while on the transfer belt 10 transfer. The first band 4 runs after the delivery point 7 via a guide roller 35 and over guide rollers 39 back again. The guide rolls 39 are arranged on a zigzag-shaped line about a substantially horizontally oriented line so that the first forming belt is returned substantially horizontally. After the decrease suction element 9 the transfer belt runs 10 vertical, that is, at an angle 40 from 90 ° to the direction of manufacture 38 tilted, up to the transfer point 23 at the multi-layer fibrous web 2 to the underfelt 21 is handed over. Thus, the transfer zone runs 22 at an angle 40 from 90 ° to the direction of manufacture 38 , Inside through the transfer belt 10 formed loop are in this example three separate transfer suction 24.1 . 24.2 . 24.3 arranged. The first transfer suction element 24.1 , the second transfer suction element 24.2 and the third transfer suction element 24.3 are in this example each designed as a suction box and in the transfer zone 22 arranged. The to the transfer band 10 facing sides of the separate transfer suction 24.1 . 24.2 . 24.3 are provided with an open, water-permeable ceramic coating. The separate transfer suction elements 24.1 . 24.2 . 24.3 are each aspirated to increase the drainage, with the respective negative pressure in the separate transfer suction 24.1 . 24.2 . 24.3 is independently adjustable. The negative pressure in the suction zones is more than 20kPa. The vacuum supply and the transfer suction elements 24.1 . 24.2 . 24.3 are designed such that the negative pressure is rising from Transfersaugelement to Transfersaugelement adjustable. So can the first transfer suction 24.1 a negative pressure of more than 20kPa, the second transfer suction 24 .a vacuum of more than 30 kPa and the third transfer suction element 24.3 have a negative pressure of more than 40kPa. Through the transfer suction elements 24.1 . 24.2 . 24.3 becomes the multilayer fibrous web 2 further dehydrated, wherein the dewatering direction now in the opposite direction to the direction of drainage on the first Formierband 4 runs. This arrangement allows drainage on the first forming belt 4 reduce, for example, by lower dewatering pressures, without the dry content of the multilayer fibrous web 2 at the entrance to the press section 11 to diminish. A graying of the first situation 2a is thus counteracted. The separate transfer suction elements 24.1 . 24.2 . 24.3 each have a collecting trough 41 for collection and removal of the white water, preferably on the drive side of the paper machine on. The respective collecting trough 41 In this case, it extends transversely to the production direction and has a laterally arranged connection or a plurality of connections distributed transversely to the production direction for discharging the white water. The collecting trough 41 is arranged and designed so that when dewatering the multilayer fibrous web 2 incurred white water can flow freely through the action of gravity. By this arrangement, the removal of, through which in the transfer zone 22 instead of finding drainage of the multilayer fibrous web 2 , resulting white water improves and facilitates. The dewatered white water is dischargeable due to its kinetic energy and gravity effect. In the vertical arrangement of the transfer zone 22 No vacuum support is necessary for the discharge. The white water can be released from the three separate transfer suction elements 24.1 . 24.2 . 24.3 be removed without having to overcome overflow weirs, as in the horizontal arrangement of the transfer zone 22 the case is. The suction roller 9 is a separate gutter 28 assigned to the discharge of the centrifuged white water.

The 5 a section with a further embodiment of the device according to the invention 1 that differ from the in 4 shown embodiment by a lowered collection point 7 different. Also in this example runs the first Formierband 4 after the delivery point 7 via a guide roller 35 and over guide rollers 39 back again. The guide rolls 39 are on a zigzag-shaped, arranged around a substantially horizontally oriented line, leaving the first forming band 4 is returned substantially horizontally. The vertical distance of the deflection roller 35 to the Saugumlenkwalze 34 is enlarged and the delivery point 7 on a horizontal plane below the substantially horizontally oriented line, around which the guide rollers are placed in a zigzag pattern. In this example, the delivery point is 7 on one below the one by the first forming band 4 formed loop lying horizontal plane. As a result, the height of the subsequent press section 11 reduced or an increase in the height of the press as a result of a horizontal inclined to the transfer zone 22 counteracted.

LIST OF REFERENCE NUMBERS

1

contraption

2

multilayer fibrous web

2a

first location

2 B

second location

3

Wire section

3a

first forming unit

3b

second forming unit

4

first banding tape

5

Vergautschungszone

6

couch roll

7

delivery point

8th

removal device

9

Abnahmesaugelement

10

another band, transfer band

11

press section

12

first press nip

13

second press nip

14

third press nip

15

first pressing element

16

second pressing element

17

third pressing element

18

counter-element

19

smoothing belt

20

overfelt

21

bottom felt

22

transfer zone

23

Transfer point

24

transfer suction

24.1

first transfer suction element

24.2

second transfer suction element

24.3

third transfer suction element

25

first suction zone

26

second suction zone

27

third suction zone

28

gutter

29

Dampfblasvorrichtung

30

Dampfblasvorrichtung

31

web stabilizer

32

Edge cutter

33

scraper

34

suction turning roll

35

deflecting

36

headbox

37

drying section

38

making direction

39

guide roll

40

angle

41

collecting channel

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

• DE 102014210879 A1 [0003]
• DE 112009002741 T5 [0004]
• DE 60027739 T2 [0005, 0006]

Claims (15)

Apparatus (1) for producing a multilayer fibrous web (2), comprising a wire section (3) for forming the multilayer fibrous web (2), a press section (11) for further dewatering the multilayer fibrous web (2) and a drying section (37) for drying the multi-layer fibrous web (2), wherein the wire section (3) comprises a first air-permeable forming belt (4) arranged to form a first layer (2a) of the multi-ply fibrous web (2) and which comprises the formed multi-ply fibrous web (2) a take-off point (7) with a removal device (8) leads, wherein the removal device (8) comprises a Abnahmesaugelement (9) and this another looping around the belt (10) and the multi-layer fibrous web (2) by the removal device (8) at the take-off point (7) is removed from the first air-permeable forming belt (4) and the press section (11) comprises at least three press nips (12, 13, 14), wherein the last two press nips (13, 14) by e in the third pressing element (17) and a second pressing element (16) and a common counter element (18) with a smooth surface for smoothing the first air-permeable forming belt (4) in direct contact side of the first layer (2a) of the multilayer fibrous web (2 ), and the first press nip (12) is formed by the second press element (16) of the second press nip (13) and a first press element (15), characterized in that the first press nip (12) is double felted and has an upper felt (20) and an underfelt (21) and that the further band (10) is designed as an air-permeable transfer belt (10) and to form a transfer zone (22) from the take-off point (7) to a transfer point (23) of Fiber web (2) to the lower felt (21) of the first press nip (12) extends. Device after Claim 1 , characterized in that the transfer zone (22) at an angle (40) between 0 ° to 120 °, in particular between 20 ° to 120 °, preferably between 80 ° to 120 ° to the production direction (38) is aligned. Device after Claim 1 or 2 , characterized in that in the loop formed by the transfer belt (10) a transfer suction element (24), preferably a suction box, with at least one suction zone (25, 26, 27), preferably with at least two suction zones (25, 26, 27), in particular with at least three suction zones (25, 26, 27) is arranged in the production direction in the region of the transfer zone (22). Device after Claim 1 or 2 , characterized in that the transfer suction (24) at least two suction zones (25, 26, 27) in the manufacturing direction (38) and the negative pressure in the suction zones (25, 26, 27) in the manufacturing direction (38) is adjustable. Device according to one of Claims 1 to 4 , characterized in that the transfer suction element (24) by several separate transfer suction (24.1, 24.2, 24.3) is formed, which are preferably designed in each case as a suction box. Device according to one of the preceding claims, characterized in that the Abnahmesaugelement (9) is designed as a suction roll or as a tube suction or as a flat suction. Device according to one of the preceding claims, characterized in that the Abnahmesaugelement (9) is designed as a suction roll and a suction roller of the functionally associated groove (28) is provided, which is preferably integrated in the transfer suction (24). Device according to one of the preceding claims, characterized in that the air permeability of the transfer belt (10) is greater, in particular at least twice as large, as the air permeability of the first Formierbandes (4). Device according to one of the preceding claims, characterized in that the transfer belt (10) is designed as a sieve fabric or as an air-permeable membrane or as a spiral sieve. Device according to one of the preceding claims, characterized in that the transfer belt (10) is free of a press nip. Device according to one of the preceding claims, characterized in that the wire section (3) at least one first forming unit (3a) with the first forming belt (4) for forming the first layer (2a) of the multilayer fibrous web (2) and at least one second forming unit ( 3b) for forming a second layer (2b) of the multi-ply fibrous web (2) and a Vergautschungszone (5) and the forming units (3a, 3b) arranged and formed to each other that the second layer (2b) of the multilayer fibrous web (2) on the the first layer (2a) of the multi-ply fibrous web (2) in the Vergautschungszone (5) for forming the multilayer fibrous web (2) is vergautscht. Device according to one of the preceding claims, characterized in that the multilayer fibrous web (2) comprises white-covered liners, in particular white top testliners with a cover layer and a backsheet, and the wire section (2) is set up so that the cover layer is the first layer (FIG. 2a) of the multilayer fibrous web (2). Device according to one of the preceding claims, characterized in that the common counter-element (18) of the second and the third press nips (13, 14) is designed as a roller with a smooth surface. Device according to one of Claims 1 to 12 , characterized in that the common counter-element (18) of the second and the third press nips (13, 14) is designed as a roller with a smoothing surface (19) having a smooth surface that wraps around it. Method for producing a multilayer fibrous web (2) which is formed in a wire section (3), further dewatered in a press section (11) and dried in a dryer section (37), wherein in the wire section (3) a first layer (2a) the multi-ply fibrous web (2) is formed on a first air-permeable forming belt (4) and the formed multi-ply fibrous web (2) is guided through the first air-permeable forming belt (4) to a take-off point (7) with a take-off device (8), wherein the take-off device (8) comprises a Abnahmesaugelement (9) and this another wrap around band (10) and the multi-layer fibrous web (2) by the removal device (8) at the take-off point (7) from the first air-permeable Formierband (4) by the further band (10 ) is removed and the press section (11) with at least three press nips (12, 13, 14) is guided, wherein the two last press nips (13, 14) by a third pressing element and a second Pressing element and a common counter-element (18) are formed with a smooth surface and wherein the first air-permeable Formierband (4) in direct contact side of the first layer (2a) of the multilayer fibrous web (2) with the common counter-element (18) in direct Contact is brought and smoothed and wherein the first press nip (12) by the second pressing member (16) of the second press nip (13) and a first pressing member (15) is formed, characterized in that the first press nip (12) is double felted and an upper felt (20) and a lower felt (21) and that the further band (10) is designed as an air-permeable transfer belt (10) and in that the multilayer fibrous web (2) at a transfer point (23) from the transfer belt (10) to the Subfelt (21) of the first press nip (12) is transferred.

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