CN110612370B - Production device and method for producing a fibrous web - Google Patents
Production device and method for producing a fibrous web Download PDFInfo
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- CN110612370B CN110612370B CN201880030613.6A CN201880030613A CN110612370B CN 110612370 B CN110612370 B CN 110612370B CN 201880030613 A CN201880030613 A CN 201880030613A CN 110612370 B CN110612370 B CN 110612370B
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- layer
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- fibrous web
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F9/00—Complete machines for making continuous webs of paper
- D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type
- D21F9/006—Complete machines for making continuous webs of paper of the twin-wire type paper or board consisting of two or more layers
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/02—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the Fourdrinier type
- D21F11/04—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the Fourdrinier type paper or board consisting on two or more layers
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F2/00—Transferring webs from wet ends to press sections
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F3/00—Press section of machines for making continuous webs of paper
- D21F3/02—Wet presses
- D21F3/04—Arrangements thereof
- D21F3/045—Arrangements thereof including at least one extended press nip
Abstract
The invention relates to a production device (1) for producing a multi-layer fibrous web (2), having a wire section (3) for forming a multi-layer fibrous web (2), a press section (11) for further dewatering of the multi-layer fibrous web (2), and a drying section (37) for drying the multi-layer fibrous web (2), wherein the wire section (3) comprises an air-permeable first forming belt (4) which is provided for forming a first layer (2a) of the multi-layer fibrous web (2) and which conveys the formed multi-layer fibrous web (2) to a take-off position (7) having a take-off device (8), wherein the extracting device (8) comprises an extracting suction element (9) and a further belt surrounding the extracting suction element, and the multi-layered fibrous web (2) is removed from the air-permeable first forming belt (4) by a removal device (8) at a removal position (7). The invention also relates to a method for producing a multi-layered fibrous web.
Description
The invention relates to a production device for producing a multi-layered fibrous web, having a wire section for forming the multi-layered fibrous web, a press section for further dewatering the multi-layered fibrous web, and a drying section for drying the multi-layered fibrous web, wherein the wire section comprises a first air-permeable forming belt which is provided for forming a first layer of the multi-layered fibrous web and for transporting the formed multi-layered fibrous web to a removal position having a removal device, wherein the removal device comprises a removal suction element and a further belt surrounding the removal suction element, and the multi-layered fibrous web is removed from the first air-permeable forming belt by the removal device at the removal position, and the press section comprises at least three press nips, wherein the last two press nips are formed by a third press element and a second press element and a common mating element, the common mating element has a smooth surface for smoothing the side of the first layer of the multi-layer fibrous web which is in direct contact with the air-permeable first forming belt, and the first press nip is formed by the second press element and the first press element of the second press nip.
The invention also relates to a method for producing a multi-layered fibrous web.
Such a production device is known from the prior art. Document DE102014210879 a1 describes a paper machine and a method for producing a wrapping paper. A multi-layered packaging web is composed of cover, resist and backing layers and is manufactured in a wire section with two forming units and is further dewatered in a press section composed of a compact press with 3 nips and then conveyed to a dryer section and further process steps. In the wire section, the backing layer is pressed (german: aufgegautscht) onto the cover layer and is dewatered via the cover layer. This results in graying of the generally shiny overlay.
Document DE 112009002741T 5 likewise discloses a machine for producing multi-ply cardboard webs, for example White Top board (White Top Liner) with a Top and a backing ply. The individual layers are formed in the wire section, interconnected, dewatered and transferred with the press felt belt into the press section of a compact press which may be designed with three press nips.
Another machine for producing cardboard with at least two plies is described in document DE 60027739T 2. The wire section consists of two forming units for the manufacture of the cover layer and the backing layer together with the subsequent extrusion of the dewatered board web. The board web is then transferred by a press belt into a press section and further dewatered. The press section consists of a compact press with three nips. This is followed by a drying section and further process sections. In the wire section, the backing layer is pressed (german: aufgegautscht) onto the cover layer and is dewatered via the cover layer. As mentioned above, this results in graying of the generally shiny overlay.
The known production devices either have the disadvantage that the bright cover layer of high quality is greyed, which leads to a reduction in quality, or the paper machine configuration is very complex and expensive to build. In document DE 60027739T 2, in one embodiment (of fig. 3), the cover layer is arranged above in the wire section in order to avoid dewatering of the backing layer via the cover layer. This however requires a costly press section arrangement (in the form of a reverse compact press with poor runnability) or an additional fourth press for smoothing the surface of the cover sheet.
The object of the present invention is therefore to propose a production device for producing a multi-layer fibrous web, for example White cardboard (White Top Liner) or White Top box board (White Top Test Liner), which on the one hand ensures good runnability of the fibrous web in a paper machine and on the other hand overcomes quality defects, for example due to the ashing and low flatness of the high-quality layers, for example the bright cover layers, of the multi-layer fibrous web.
A production device for producing a multi-layered fibrous web for a paper machine is proposed, having a wire section for forming the multi-layered fibrous web, a press section for further dewatering the multi-layered fibrous web, and a drying section for drying the multi-layered fibrous web, wherein the wire section comprises a first air-permeable forming belt which is provided for forming a first layer of the multi-layered fibrous web and for transporting the formed multi-layered fibrous web to a removal position having a removal device, wherein the removal device comprises a removal suction element and a further belt surrounding the removal suction element, and the multi-layered fibrous web is removed from the first air-permeable forming belt by the removal device at the removal position, and the press section comprises at least three press nips, wherein the last two press nips are formed by a third press element and a second press element and a common mating element, the common mating element has a smooth surface for smoothing the side of the first layer of the multi-layer fibrous web which is in direct contact with the air-permeable first forming belt, and the first press nip is formed by the second press element and the first press element of the second press nip. According to the invention, the first press nip is double-layered and has a top felt and a bottom felt, and the further belt is designed as an air-permeable transfer belt and extends onto the bottom felt of the first press nip in order to form a transfer zone from the removal position to the transfer position of the fibrous web.
The manufacturing device has the advantage that the first layer of the multi-layer fibrous web, which is formed on the first forming belt, is dewatered in combination with a simple pressing arrangement and the side facing the first forming belt is flattened in the press. The dewatering capacity of the press section is increased by laying a first press nip of a double felt. This arrangement is advantageously suitable for the manufacture of White board (White Top Liner) or White Top Test Liner. These paperboard types and wrapper types include a high quality, lighter top layer and a darker, usually brown, back layer. Depending on the type of cardboard, further layers are provided between these layers. Common intermediate layers are, for example, protective layers and gaskets. The invention can therefore be used particularly advantageously for producing White cardboard (White Top Liner) or White Top Liner, the first layer being formed by a cover layer.
In a further practical embodiment, a conveying suction element, preferably a suction box, with at least one suction zone in the region of the conveying zone is arranged in the loop formed by the conveyor belt. By means of the at least one suction zone, the multiply fibrous web is further dewatered, wherein the dewatering direction now extends in the opposite direction with respect to the dewatering direction on the first forming belt. This way of further dewatering achieves a reduction of dewatering on the first forming belt, for example by means of a smaller dewatering pressure, without reducing the dry weight content of the multi-layered fibrous web at the entrance into the press section. Thus resisting ashing of the first layer. By displacing the dewatering into the transfer zone, the impression of the side of the first layer of the multi-layer fibrous web to be smoothed by the forming belt is also reduced/small. Thereby achieving an improvement in the flatness of the first layer.
Advantageously, the conveying suction element has at least two, preferably at least three suction zones in the direction of production. The dewatering direction can be adjusted in this way.
In a practical case, the underpressure in the at least one suction zone can be set to a value of more than 20kPa, in particular more than 30kPa, preferably more than 40 kPa.
In a further embodiment, the conveying suction element has at least two suction zones in the production direction, and the underpressure in the suction zones is arranged in the production direction in a manner that can be raised.
It is also advantageous if the transport suction element has a water-permeable ceramic lining facing the transport belt.
Preferably, the ceramic lining comprises strips and slots, and wherein the slots are preferably greater than 10mm wide in the direction of manufacture. The slits between the strips extend over the entire width of the conveying suction element. However, it is also possible for the slot to be interrupted transversely to the direction of production by a web.
In a possible embodiment, the ceramic lining is at least partially perforated.
In addition, the ceramic lining may also comprise a combination of strips and slots and holes. The hole may be designed as a drill portion.
The relative open area of the ceramic lining is preferably about a value greater than 50%.
In a practical embodiment, the extraction suction element is designed as a suction roller or as a tubular or flat suction head. In particular, suction rolls are particularly suitable at paper machine speeds of more than 700 m/min.
The take-off suction element is preferably capable of operating with a negative pressure of more than 20kPa, in particular more than 30kPa, preferably more than 40 kPa.
In a practical case, the extraction suction element is designed as a suction roller with two suction zones arranged one behind the other in the direction of production. The first suction zone is designed as a removal suction zone and the second suction zone as a holding zone, so that a plurality of underpressure values greater than 20kPa, in particular greater than 30kPa, can be applied. It is particularly advantageous if the removal suction element is designed such that the underpressure of the second suction zone, i.e. the holding area, is greater than the underpressure of the first suction zone, i.e. the removal area. The removal suction element is thus distinguished from known removal suction elements in which the negative pressure of the second suction zone, i.e. the holding area, is lower than the negative pressure of the first suction zone, i.e. the removal area. A conveying suction element is arranged downstream of the holding region, wherein the multi-layer fibrous web is held on the conveyor belt by means of the underpressure of at least one suction zone of the conveying suction element.
In a further variant, the removal suction element is designed as a suction roller, and the suction roller is functionally assigned a groove, which is preferably integrated in the suction element of the transport suction element. The groove contains the water that is thrown off the suction roller. This water is conducted away laterally transversely to the direction of production, preferably together with the water conveying at least one suction zone of the suction element.
In an advantageous embodiment, the air permeability of the conveyor belt is greater than the air permeability of the first forming belt, in particular at least twice as great as the air permeability of the first forming belt. This achieves a high dry weight content of the multiply fibrous web and at the same time stabilizes the dewatering.
A steam blow-off device is preferably arranged upstream of the removal position for applying steam directly to the multi-layer fibrous web. The steam blowoff device extends over the entire width of the fibrous web.
In the actual case, a steam blowoff device is arranged in the region of the transfer zone for the direct application of steam to the multi-layer fibrous web. The steam blowoff device extends over the entire width of the fibrous web.
Advantageously, the forming belt is designed as a mesh fabric or as a gas-permeable membrane. For example, the forming belt is designed as a woven forming wire or as a perforated, breathable film.
The conveyor belt can be designed as a mesh screen or as an air-permeable membrane or as a spiral screen. For example, the conveyor belt is designed as a woven forming wire or as a perforated, air-permeable film. A web run stabilizer for stabilizing the web run can be assigned to the base mat on the side facing away from the fibrous web between the transfer point and the first nip.
In a practical advantageous design, the transfer belt has no nip. A nip is understood here to mean a nip which is formed, for example, by two rolls. Since the conveyor belt together with the multi-layer fibrous web is not guided through the nip, marking or structuring of the side to be smoothed is avoided.
In an exemplary design, the wire section comprises at least one first forming unit with the first forming belt for forming a first layer of the multi-layer fibrous web and at least one second forming unit for forming a second layer of the multi-layer fibrous web and a press-dewatering zone (german: Vergautschungszone). The forming units are arranged and designed relative to each other such that the second layer of the multi-layer fibrous web is pressed onto the first layer of the multi-layer fibrous web in the press-dewatering zone in order to form the multi-layer fibrous web.
Preferably, substantially no further dewatering takes place in the region from the press-dewatering zone up to the removal position of the fibrous web. The area is preferably free of dewatering elements for dewatering the fibrous web in the direction of the first forming belt.
Alternatively, the suction device can be arranged in this area on the side of the first forming belt opposite the fibrous web only for stabilizing the web run.
Advantageously, the multiply fibrous web may comprise a white-covered top layer, in particular a white-faced boxboard having a cover layer and a backing layer, and the wire section is provided as the cover layer constituting the first layer of the multiply fibrous web.
The wire section may additionally have a forming unit for constituting a further layer, such as a protective layer or a backing layer.
It is also possible that at least one further layer is formed by a multi-layer headbox in combination with a forming unit for the cover layer or a forming unit for the backing layer. In this case, a multi-layer headbox applies two layers of different fiber suspensions to the respective forming belt.
In a practical embodiment, the common mating element of the second and third nip is designed as a roller with a smooth surface for smoothing the bottom side of the first layer of the fibrous web.
In a possible embodiment, the common mating element of the second and third press nips is designed as a roller with a preferably gas-impermeable flattening belt surrounding the roller, said flattening belt having a smooth surface for flattening the bottom side of the first layer of the fibrous web.
The course of the gas-permeable conveyor belt can preferably be selected such that the direction of the conveying zone, i.e. the direction of travel of the conveyor belt in the region of the conveying zone, lies substantially between an imaginary horizontal line, i.e. the direction of production, and an imaginary vertical line. It is also conceivable that the direction of the conveying zone is selected such that the running direction of the conveyor belt has a direction component opposite to the production direction in the region of the conveying zone.
Preferably, the conveyor belt is inclined in the conveying area after the removal suction element at an angle of between 0 ° and 120 °, in particular at an angle of between 20 ° and 120 °, relative to the production direction. That is, the transport zone is oriented at an angle from 0 ° to 120 °.
Particularly advantageous is the possible orientation of the transfer zone in an angular range of 40 ° to 90 °. This makes it easier and better to drain the white water or the return water collected as a result of the dewatering of the multiply fibrous web in the transfer zone. The white water or the returned water removed can be discharged due to its kinetic energy. Depending on the orientation of the transfer zone, no vacuum is required to assist the evacuation. Especially for inclinations between 20 ° and 90 °, white or return water originating from the separate conveying suction element can flow away without additional energy input.
Advantageously, the transport zone has a feasible orientation in an angular range of 80 ° to 120 °, in particular in an angular range of 90 ° to 120 °. This makes it easier and better to drain the white water or the return water collected as a result of the dewatering of the multiply fibrous web in the transfer zone. The stripped off white or backwater can be drained off due to its kinetic energy and due to the effect of gravity. Even in this case, no vacuum is required to assist the evacuation.
By arranging the transfer zone obliquely with respect to the direction of production, a possible uncontrolled rewet of the multi-layer fibrous web can be overcome.
In a possible embodiment, the conveying suction element is formed by a plurality of individual conveying suction elements, which can each be designed, for example, as a suction box. For example, two to four suction boxes can be arranged one after the other in the region of the transfer zone. The side of the individual conveyor suction element directed toward the conveyor belt can be provided with an open, water-permeable ceramic lining. The individual conveying suction elements can each be sucked in order to lift the dewatering, wherein the respective underpressure in the individual conveying suction elements is settable, preferably independently of each other.
In a preferred practical embodiment, the individual conveying suction elements each have a collecting channel for collecting and discharging white water or return water. The collecting channel extends transversely to the direction of production and can have one or more connections for discharging white water or returning water.
In a practical case, the underpressure in at least one of the individual conveying suction elements can be set to a value of more than 20kPa, in particular more than 30kPa, preferably more than 40 kPa.
In a further possible embodiment, the underpressure in the individual conveyor suction elements can be set in an elevated manner in the direction of travel of the conveyor belt.
In particular, it is advantageous for the conveying area to be inclined relative to the horizontal plane if the removal position and, therefore, also the transfer position are arranged deeper. Thereby reducing the structural height of the subsequent press section or inhibiting an increase in the structural height of the press caused by the transport zone being inclined with respect to the horizontal.
Preferably, the take-off position is located on a horizontal plane below the loop formed by the first forming belt.
A method for producing a multi-layered fibrous web is proposed, which is embodied in a wire section, is further dewatered in a press section and dried in a dryer section, wherein a first layer of the multi-layered fibrous web is embodied in the wire section on an air-permeable first forming belt and the embodied multi-layered fibrous web is conveyed by the air-permeable first forming belt to a removal position having a removal device, wherein the removal device comprises a removal suction element and a further belt surrounding the removal suction element, and the multi-layered fibrous web is removed from the air-permeable first forming belt by the removal device at the removal position via the further belt and conveyed to the press section having at least three press nips, wherein the last two press nips are embodied by a third press element and a second press element and a common mating element having a smooth surface and wherein, the side of the first layer of the multi-layer fibrous web which is in direct contact with the air-permeable first forming belt is brought into direct contact with a common counter element and is flattened, and the first press nip is formed by the second press element of the second press nip and the first press element. According to the invention, the method is characterized in that the first nip is double-layered and has a top felt and a bottom felt, and the further belt is designed as an air-permeable transfer belt and the multi-layer fibrous web is transferred from the transfer belt to the bottom felt of the first nip at a transfer location.
The invention also explicitly comprises embodiments which are not given by the combination of features which is explicitly cited in the claims, so that the features disclosed in the invention can be combined with one another in any desired manner as far as technically feasible.
Further features and advantages of the invention will emerge from the following description of a preferred embodiment with reference to the accompanying drawings.
In the attached drawings
Figure 1 shows a schematic view of an embodiment of a manufacturing apparatus according to the invention with a transfer belt between a wire section and a press section;
FIG. 2 shows a schematic view of an embodiment of a manufacturing apparatus according to the invention with an exemplary wire section design;
figure 2a shows a schematic view of a variant of the press section of the manufacturing apparatus according to the invention;
figure 3 shows a schematic view of a second variant of the design of the wire section of the manufacturing apparatus according to the invention;
figure 3a shows a schematic view of a third variant of the design of the wire section of the manufacturing apparatus according to the invention;
figure 3b shows a schematic view of a further variant of the design of the wire section of the manufacturing apparatus according to the invention;
fig. 4 shows a schematic partial view of a further embodiment of a production device according to the invention, with a conveying zone having a vertical course,
fig. 5 shows a partial diagrammatic view of a further embodiment of a production device according to the invention, with the removal location arranged deeper.
Fig. 1 shows an embodiment of a production device 1 according to the invention for producing a multi-layer fibrous web 2 for a paper machine, having a wire section 3 for forming the multi-layer fibrous web 2, a press section 11 for further dewatering the multi-layer fibrous web 2, and a drying section 37 for drying the multi-layer fibrous web 2. Between the wire section 3 and the press section 11, an air-permeable transfer belt 10 is arranged for guiding the multi-layer fibrous web 2 from the wire section 3 to the press section 11. The transfer zone 22 is here oriented substantially horizontally. That is to say, the course of the air-permeable conveyor belt 10 in the region of the conveying zone 22 downstream of the removal suction element 9 is designed horizontally. The wire section 3 has an air-permeable first forming belt 4, the first forming belt 4 being arranged to constitute a first layer of the multi-layer fibrous web 2. By means of a removal device 8 formed by an air-permeable conveyor belt 10 and a removal suction element 9, the multi-layer fibrous web 2, i.e. the first layer together with at least one further layer, is removed from the first forming belt 4 at a removal position 7 and is transferred onto the air-permeable conveyor belt 10 (known as a "pick-up" position) there. Before the withdrawal position 7, the first forming belt 4 is guided by a screen deflecting roller 34. Here, the air-permeable conveyor belt 10 surrounds a removal suction element 9, which removal suction element 9 is designed in this case as a suction roller 9, wherein the applied negative pressure is greater than 20 kPa. The first forming belt 4 runs after the removal position 7 via the deflecting roller 35 and returns again via the guide roller 39. The guide rollers 39 are arranged in a zigzag around a substantially horizontally oriented straight line, so that the first forming band is guided back substantially horizontally. The air-permeable conveyor belt 10 extends so as to form a transfer zone 22 from the take-off location 7 to a transfer location 23, at which transfer location 23 the fibrous web 2 is transferred to the bottom felt 21 of the first nip 12. In the region of the removal position 7 and the transfer position 23, the multi-layer fibrous web 2 is supported at all times. These transfer positions are therefore designed without open web traction. Inside the loop formed by the air-permeable conveyor belt 10, a suction box 24 is used in this case as a conveying suction element 24. The suction box 24 has three suction zones 25,26,27 and is arranged in the region of the transfer zone 22. The underpressure in the suction zone is greater than 20 kPa. The negative pressure supply and/or the suction box 24 is configured such that the negative pressure can be set to rise from suction zone to suction zone. Thus, the first suction zone 25 may have a negative pressure of more than 20kPa, the second suction zone 26 may have a negative pressure of more than 30kPa and the third suction zone 27 may have a negative pressure of more than 40 kPa. Through these suction zones, the multiply fibrous web is further dewatered, wherein the dewatering direction now extends in the opposite direction with respect to the dewatering direction on the first forming belt 4. This achieves a reduction of the dewatering on the first forming belt 4, for example by means of a lower dewatering pressure, without reducing the dry weight content of the multi-layer fibrous web 2 at the inlet into the press section. Thus suppressing ashing of the first layer. By displacing the dewatering into the transfer zone 22, the marking of the side of the first layer 2a of the multi-layer fibrous web 2 to be smoothed by the first forming belt 4 is also reduced. Whereby an improved levelling of the first layer 2a is achieved. In front of the first suction zone 25, viewed in the direction of production, a groove 28 assigned to the suction roller 9 for discharging the thrown-off return water is arranged on the conveying suction element 24 and is preferably integrated therein. The transport suction element 24 has a water-permeable ceramic lining facing the gas-permeable transport belt 10. The ceramic liner design was provided with strips and slots with a slot width of 12mm between the strips.
The press section 11 is formed by three press nips 12, 13, 14, wherein the last two press nips 13, 14 are formed by a third press element 17 and a second press element 16 and a common mating element 18 with a smooth surface for smoothing the side of the first layer 2a of the fibrous web 2 that is in direct contact with the air-permeable first forming belt 4, and the first press nip 12 is formed by the second press element 16 and the first press element 15 of the second press nip 13. The third press element 17 of the third press nip 14 is designed as a shoe roll in order to constitute an extended press nip. However, it is also conceivable to provide a nip formed by two press rolls at this point. The common mating element 18 is designed as a roller with a smooth lining or a smooth coating. The first nip 12 is double-layered and has a top felt 20 and a bottom felt 21. The second press element 16 is designed as a suction press roll and contributes both to the dewatering of the multi-layered fibrous web and to its runnability, i.e. the running properties of the fibrous web 2. After passing through the three nips 12, 13, 14, the fibrous web 2 reaches the drying wire of the drying section 37 by means of open draw. At least the first dryer group of the dryer section 37 is designed as a single-row dryer section. Only the first drying cylinder and the subsequent suction rollers are shown in fig. 1. A scraper 33 is provided at the mating element 18 for keeping the smooth surface clean.
Viewed in the direction of production 38, a suction deflecting roller 34 for deflecting the first forming belt 4 is arranged upstream of the removal position 7. In order to improve the dewatering of the multi-layer fibrous web 2, a steam blowoff device 29 is provided upstream of the suction deflection roller 34. It is likewise possible to install steam blowoff devices 30 in the region of the transfer zone 22. In order to improve the runnability of the multi-layer fibrous web 2, a web stabilizer 31 is arranged in the area of the bottom felt 21 in the loop formed by the bottom felt 21 before the first press nip 12. In the region of the first forming belt 4, in the region of the transfer zone 22 and after the first press nip 14, trimming devices 32 can be provided for shearing the multi-layer fibrous web 2 on both sides. The separated trimmings are thus guided away and discharged from the first forming belt 4 after the removal position 7 and/or from the remaining fibrous web 2 in the region of the counter element 18. Disposed downstream of the removal position 7, inside the loop formed by the first forming belt 4, a deflecting roller 35 is provided, which deflecting roller 35 is designed pivotably in order to open and close the gap between the air-permeable conveyor belt 10 and the first forming belt 4. The removal position 7 can thus be opened and closed, for example in the event of web breaks.
A schematic diagram of an embodiment of a manufacturing apparatus according to the invention with an exemplary wire section design is shown in fig. 2. The first forming belt 4 is designed as a long screen and forms a first forming unit 3a, on which first forming unit 3a the first layer 2a of the multi-layer fibrous web 2 is formed. A headbox 36 is assigned to the first forming belt 4 for applying the fiber suspension. The fibre suspension is dewatered by means of known dewatering elements via a first forming belt and thus constitutes a first layer 2 a. The wire section 3 has a second forming unit 3b arranged above the first forming unit 3a, which second forming unit 3b constitutes a second layer 2b of the multi-layered fibrous web 2. The second layer 2b of the multi-layer fibrous web 2 is pressed onto the first layer 2a by means of a couch roll 6 in the press dewatering zone 5 and forms the multi-layer fibrous web 2. In the case of a two-layer fibrous web 2, the second layer is extruded directly onto the first layer. For a three-or four-layer fibrous web with one or two intermediate layers, the second layer is pressed onto one intermediate layer. Three or four layers of fibrous web may be produced by additional forming units and/or by a multi-layer headbox in conjunction with the wire section. The second forming unit 3b is configured as a double screen former. The fibre suspension delivered by the headbox 36 is dewatered between two forming belts to form a second layer 2 b. The description of the further elements provided with reference numbers is given with reference to fig. 1. Elements that coincide with each other are provided with the same reference numerals.
Fig. 2a shows a variant of the press section of the production device according to the invention according to fig. 1 and 2. The common mating element 18 of the second and third press nips 13, 14 is designed as a roller with a preferably gas-impermeable flattening belt 19 surrounding the roller, said flattening belt having a smooth surface for flattening the bottom side of the first layer 2a of the fibrous web 2. The multi-layered fibrous web 2 is removed directly from the flattening belt 19 by the drying screen of the subsequent drying section without open draw.
In fig. 3, 3a and 3b, schematic views of further variants of the design of the wire section of the production device according to the invention are shown. In fig. 3, a second forming unit 3b is arranged above the first forming unit 3a formed by the first forming belt 4. The second forming unit is likewise designed as a long screen. Additionally, the elongated screen is provided with additional forming wires for dewatering of both sides of the second layer 2 b. The difference between figure 3a and the wire section 3 shown in figure 3 is that the first layer 2a is dewatered on both sides in partial sections before the press dewatering zone 5. The first forming belt 4 is assigned a top screen for dewatering the fibrous web upwards. The first forming unit 3a is therefore designed as a hybrid former. In the wire section 3 shown in fig. 3b, the first layer 2a of the multiply fibrous web 2 is dewatered to both sides in a first forming unit 3a designed as a twin-wire former. The first forming unit 3a is therefore designed as a gap former. In all three variants of the wire section, the multi-layer fibrous web 2 is guided by the first forming belt 4 up to the removal position 7 by the air-permeable conveyor belt 10. Substantially no more dewatering takes place from the press dewatering zone 5 up to the take-off position 7. For further description of the elements provided with reference signs, reference is made to the description of the figures mentioned above. Elements that coincide with each other are provided with the same reference numerals.
Fig. 4 shows a schematic partial view of a further embodiment of a production device 1 according to the invention with a vertical transfer zone 22, i.e. running at an angle 40 of 90 ° relative to the production direction. This possible embodiment is an alternative to the horizontally running embodiment with a transfer zone 22 shown in the preceding figures. The multi-layered fibrous web 2 is removed from the first forming belt 4 at the removal point 7 by means of a removal device 8 formed by an air-permeable conveyor belt 10 and a removal suction element 9 and is transferred to the air-permeable conveyor belt 10. The first forming belt 4 runs after the removal position 7 via the deflecting roller 35 and returns again via the guide roller 39. The guide rollers 39 are arranged in a zigzag around a substantially horizontally oriented straight line, so that the first forming band is guided back substantially horizontally. The air-permeable conveyor belt 10 extends vertically after the removal suction element 9, i.e. obliquely upward at an angle 40 of 90 ° to the direction of production 38, as far as a transfer position 23, at which the multi-layer fibrous web 2 is transferred onto the base mat 21. Thus, the transfer zone 22 also extends at an angle 40 of 90 ° relative to the manufacturing direction 38. Inside the loop formed by the air-permeable conveyor belt 10, in this example three separate conveyor suction elements 24.1,24.2,24.3 are arranged. The first conveying suction element 24.1, the second conveying suction element 24.2 and the third conveying suction element 24.3 are each designed as a suction box in the present case and are arranged in the region of the conveying zone 22. The side of the individual transport suction elements 24.1,24.2,24.3 facing the air-permeable transport belt 10 is provided with an open water-permeable ceramic lining. The individual transfer suction elements 24.1,24.2,24.3 are each sucked in order to lift the dewatering, wherein the respective underpressure in the individual transfer suction elements 24.1,24.2,24.3 is settable independently of one another. The underpressure in the suction zone is greater than 20 kPa. The vacuum supply and the transport suction elements 24.1,24.2,24.3 are designed such that the vacuum can be set in an elevated manner one by one. Thus, the first conveying suction element 24.1 may have a negative pressure of more than 20kPa, the second conveying suction element 24.2 may have a negative pressure of more than 30kPa and the third conveying suction element 24.3 may have a negative pressure of more than 40 kPa. By means of these conveying suction elements 24.1,24.2,24.3, the multi-layer fibrous web 2 is dewatered further, wherein the dewatering direction now extends in the opposite direction to the dewatering direction on the first forming belt 4. This arrangement enables a reduction of the dewatering on the first forming belt 4, for example by a smaller dewatering pressure, without reducing the dry weight content of the multiply fibrous web 2 at the entrance into the press section 11. Thus, ashing of the first layer 2a is suppressed. The individual transfer suction elements 24.1,24.2,24.3 each preferably have a collecting channel 41 on the drive side of the paper machine for collecting and discharging white water or backwater. The respective collecting channel 41 extends transversely to the production direction and has a laterally arranged connection or a plurality of connections running transversely to the production direction for discharging white water or returning water. The collecting channel 41 is arranged and designed in such a way that the white water or the return water which accumulates during dewatering of the multiply fibrous web 2 can be drained freely by the action of gravity. This arrangement makes it possible to better and easier to drain the white water or the return water collected as a result of the dewatering of the multi-layer fibrous web 2 in the transfer zone 22. The removed white or backwater can be drained off because of its kinetic energy and due to gravity. In the vertical arrangement of the transfer zone 22, no vacuum assisted venting is required. The white water or the return water can be freely discharged from the three individual conveying suction elements 24.1,24.2,24.3 without having to pass over the overflow protection, which also applies in the case of a horizontal arrangement of the conveying zone 22. A separate gutter 28 is assigned to the suction roller 9 in order to discharge the thrown-off white water or the return water.
Fig. 5 shows a partial diagrammatic view of a further embodiment of the production device 1 according to the invention, which differs from the embodiment shown in fig. 4 by a deeper arrangement of the removal location 7. In this example, the first forming belt 4 also runs after the removal position 7 via the deflecting roller 35 and returns again via the guide roller 39. The guide rollers 39 are arranged in a zigzag around a substantially horizontally oriented straight line, so that the first forming belt 4 is guided back substantially horizontally. The vertical distance of the deflecting rollers 35 relative to the suction deflecting roller 34 increases and the removal position 7 is arranged in a horizontal plane below a substantially horizontally oriented straight line around which the guide rollers are positioned zigzag-like. In this embodiment, the take-off position 7 is located on a horizontal plane below the loop formed by the first forming belt 4. Thereby reducing the structural height of the subsequent press section 11 and/or suppressing an increase in the structural height of the press caused by the transfer zone 22 being inclined with respect to the horizontal.
List of reference numerals:
1 manufacturing apparatus
2 Multi-layer fibrous Material Web
2a first layer
2b second layer
3 net part
3a first Forming Unit
3b second Forming Unit
4 first Forming Belt
5 squeezing dewatering zone
6 couch roll
7 material taking position
8 taking device
9 reclaiming suction element
10 air permeable conveyor belt
11 press section
12 first nip
13 second nip
14 third nip
15 first pressing element
16 second press element
17 third press element
18 mating element
19 leveling belt
20 top felt
21 bottom felt
22 transfer zone
23 transfer position
24 conveying suction element
24.1 first conveying suction element
24.2 second conveying suction element
24.3 third conveying suction element
25 first suction zone
26 second suction zone
27 third suction zone
28 groove
29 steam blowing device
30 steam blowing device
31 breadth stabilizer
32 side cut device
33 scraper
34 suction turning roll
35 steering roller
36 head box
37 drying part
38 direction of manufacture
39 guide roller
40 degree angle
41 collecting channel
Claims (24)
1. A production device (1) for producing a multi-layer fibrous web (2), the production device (1) having a wire section (3) for forming the multi-layer fibrous web (2), a press section (11) for further dewatering the multi-layer fibrous web, and a drying section (37) for drying the multi-layer fibrous web (2), wherein the wire section (3) comprises an air-permeable first forming belt (4) which is provided for forming a first layer (2a) of the multi-layer fibrous web (2) and for transporting the formed multi-layer fibrous web (2) to a removal position (7) having a removal device (8), wherein the removal device (8) comprises a removal suction element (9) and a further belt surrounding the removal suction element, and the multi-layer fibrous web (2) is removed from the air-permeable first forming belt (4) by the removal device (8) at the removal position (7), and the press section comprises at least three press nips, namely a first press nip (12), a second press nip (13) and a third press nip (14), wherein the second press nip (13) and the third press nip (14) are formed by a third press element (17) and a second press element (16) and a common mating element (18), said common mating element (18) having a smooth surface for leveling the side of the first layer (2a) of the multi-layered fibrous web (2) that is in direct contact with the air-permeable first forming belt (4), and the first press nip (12) is formed by the second press element (16) and the first press element (15) of the second press nip (13),
it is characterized in that the preparation method is characterized in that,
the first press nip (12) is double-layered and has a top felt (20) and a bottom felt (21), and the further belt is designed as an air-permeable conveyor belt (10) and extends onto the bottom felt (21) of the first press nip (12) in order to form a transfer zone (22) from the removal location (7) up to a transfer location (23) of the multi-layer fibrous web (2),
wherein a conveying suction element (24) is arranged in the loop formed by the air-permeable conveyor belt (10), the conveying suction element (24) having at least one suction zone (25,26,27) in the manufacturing direction in the region of the conveying zone (22).
2. The manufacturing apparatus according to claim 1,
it is characterized in that the preparation method is characterized in that,
the transfer zone (22) is inclined at an angle of between 0 ° and 120 ° with respect to the manufacturing direction (38).
3. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the conveying suction element (24) has at least two suction zones (25,26,27) in the production direction (38), and the underpressure in the plurality of suction zones (25,26,27) is arranged in a manner that can be raised in the production direction (38).
4. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the conveying suction element (24) is formed by a plurality of individual conveying suction elements (24.1,24.2, 24.3).
5. The manufacturing apparatus according to claim 1 or 2,
the removal suction element (9) is designed as a suction roller or a tubular or flat suction head.
6. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the extraction suction element (9) is designed as a suction roller and is provided with a groove (28) functionally associated with the suction roller.
7. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the air-permeable conveyor belt (10) has an air permeability greater than that of the first forming belt (4).
8. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the air-permeable conveyor belt (10) is designed as a mesh screen or as an air-permeable membrane.
9. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the air permeable conveyor belt (10) has no nip.
10. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the wire section (3) comprises at least one first forming unit (3a) with the first forming belt (4) for forming a first layer (2a) of the multi-layer fibrous web (2), at least one second forming unit (3b) for forming a second layer (2b) of the multi-layer fibrous web (2), and a press-dewatering zone (5), and the forming units (3a,3b) are arranged and configured relative to each other such that the second layer (2b) of the multi-layer fibrous web (2) is pressed onto the first layer (2a) of the multi-layer fibrous web (2) in the press-dewatering zone (5) in order to form the multi-layer fibrous web (2).
11. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the multi-layer fibrous web (2) comprises a white-covered top layer and the wire section (3) is arranged as a cover layer constituting a first layer (2a) of the multi-layer fibrous web (2).
12. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the common mating elements (18) of the second nip (13) and the third nip (14) are designed as rolls with smooth surfaces.
13. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the common mating elements (18) of the second nip (13) and the third nip (14) are designed as rolls with a smooth-surfaced flat belt (19) surrounding the rolls.
14. The manufacturing apparatus according to claim 1,
it is characterized in that the preparation method is characterized in that,
the conveying suction element (24) is a suction box.
15. The manufacturing apparatus according to claim 1,
it is characterized in that the preparation method is characterized in that,
the conveying suction element (24) has at least two suction zones (25,26,27) in the production direction in the region of the conveying zone (22).
16. The manufacturing apparatus as set forth in claim 15,
it is characterized in that the preparation method is characterized in that,
the conveying suction element (24) has at least three suction zones (25,26,27) in the production direction in the region of the conveying zone (22).
17. The manufacturing apparatus according to claim 2,
it is characterized in that the preparation method is characterized in that,
the transfer zone (22) is inclined at an angle of between 20 ° and 120 ° with respect to the manufacturing direction (38).
18. The manufacturing apparatus as set forth in claim 17,
it is characterized in that the preparation method is characterized in that,
the transfer zone (22) is inclined at an angle of between 80 ° and 120 ° with respect to the manufacturing direction (38).
19. The manufacturing apparatus according to claim 4,
it is characterized in that the preparation method is characterized in that,
the conveying suction element (24) is formed by a plurality of individual conveying suction elements (24.1,24.2,24.3) each designed as a suction box.
20. The manufacturing apparatus according to claim 6,
it is characterized in that the preparation method is characterized in that,
the grooves are integrated in the conveying suction element (24).
21. The manufacturing apparatus according to claim 7,
it is characterized in that the preparation method is characterized in that,
the air-permeable conveyor belt (10) has an air permeability at least twice greater than the air permeability of the first forming belt (4).
22. The manufacturing apparatus as set forth in claim 11,
it is characterized in that the preparation method is characterized in that,
the multi-ply fibrous web (2) comprises a white-faced boxboard having a cover ply and a backing ply.
23. The manufacturing apparatus according to claim 1 or 2,
it is characterized in that the preparation method is characterized in that,
the air-permeable conveyor belt (10) is designed as a spiral screen.
24. A method for producing a fibrous multilayer web (2) which is structured in a wire section (3), is further dewatered in a press section (11) and is dried in a drying section (37), wherein a first layer (2a) of the fibrous multilayer web (2) is structured in the wire section (3) on an air-permeable first forming belt (4) and the structured fibrous multilayer web (2) is conveyed by the air-permeable first forming belt (4) to a take-off position (7) having a take-off device (8), wherein the take-off device (8) comprises a take-off suction element (9) and a further belt surrounding the take-off suction element, and the fibrous multilayer web (2) is taken off from the air-permeable first forming belt (4) by the take-off device (8) at the take-off position (7) via the further belt and is conveyed to a machine having at least three press nips, namely a first press nip (12), a second press nip (13) and a press section (11) of a third press nip (14), wherein the second press nip (13) and the third press nip (14) are formed by a third press element and a second press element and a common mating element (18) having a smooth surface, and the side of the first layer (2a) of the multi-layered fibrous web (2) that is in direct contact with the air-permeable first forming belt (4) is brought into direct contact with the common mating element (18) and is flattened, and wherein the first press nip (12) is formed by a second press element (16) and a first press element (15) of the second press nip (13),
it is characterized in that the preparation method is characterized in that,
the first press nip (12) is double-layered and has a top felt (20) and a bottom felt (21), and the further belt is designed as an air-permeable conveyor belt (10) and extends to form a transfer zone (22) from a take-off point (7) up to a transfer point (23) and a multi-layer fibrous web (2) is transferred from the air-permeable conveyor belt (10) to the bottom felt (21) of the first press nip (12) at the transfer point (23),
wherein a conveying suction element (24) is arranged in the loop formed by the air-permeable conveyor belt (10), the conveying suction element (24) having at least one suction zone (25,26,27) in the manufacturing direction in the region of the conveying zone (22).
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102017110032.6A DE102017110032A1 (en) | 2017-05-10 | 2017-05-10 | Apparatus and method for producing a fibrous web |
| DE102017110032.6 | 2017-05-10 | ||
| DE102017111869.1 | 2017-05-31 | ||
| DE102017111869.1A DE102017111869A1 (en) | 2017-05-31 | 2017-05-31 | Apparatus and method for producing a fibrous web |
| PCT/EP2018/059350 WO2018206216A1 (en) | 2017-05-10 | 2018-04-12 | Device and method for producing a fibrous web |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110612370A CN110612370A (en) | 2019-12-24 |
| CN110612370B true CN110612370B (en) | 2022-01-28 |
Family
ID=61966012
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880030613.6A Active CN110612370B (en) | 2017-05-10 | 2018-04-12 | Production device and method for producing a fibrous web |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP3622112A1 (en) |
| CN (1) | CN110612370B (en) |
| WO (1) | WO2018206216A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102020101913A1 (en) * | 2020-01-28 | 2021-07-29 | Voith Patent Gmbh | Device for the production of White Top Kraftliner and use of this device for the production of White Top Kraftliner |
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| SE514973C2 (en) | 1999-09-07 | 2001-05-21 | Valmet Karlstad Ab | Method and paper machine for making a liner |
| DE102014210879A1 (en) | 2014-06-06 | 2015-12-17 | Voith Patent Gmbh | Process for the production of multi-ply packaging paper, paper machine for the production of multi-ply packaging paper and multi-ply packaging paper produced by this process |
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- 2018-04-12 EP EP18717357.0A patent/EP3622112A1/en active Pending
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- 2018-04-12 CN CN201880030613.6A patent/CN110612370B/en active Active
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| CN1048813A (en) * | 1989-05-30 | 1991-01-30 | 维美德造纸机械有限公司 | The press section of paper machine or lap machine |
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| DE19929888A1 (en) * | 1998-06-30 | 2000-01-20 | Valmet Corp | Papermaking machine transfer system carries band of paper from formation to pressing section with pick-up and suction roller system |
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Also Published As
| Publication number | Publication date |
|---|---|
| WO2018206216A1 (en) | 2018-11-15 |
| CN110612370A (en) | 2019-12-24 |
| EP3622112A1 (en) | 2020-03-18 |
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