EP1589132B1 - Carding machine with a rotating suction transfer device - Google Patents

Description

TECHNICAL AREA

The present invention relates to the production of nonwovens by means of a card of the type comprising at least one detaching cylinder ensuring the recovery of a fiber web at the card outlet with a point of upward curl. Its main objects are a new card whose output has been perfected so as to improve the quality of the fiber veil produced. The invention preferably, but not exclusively, applies to the high-speed production of nonwovens composed of synthetic fibers of the polypropylene, polyethylene, ... type of natural fibers of the cotton type, ..., or of artificial fibers. viscose type, ...

PRIOR ART

• au moins un tambour de cardage rotatif, encore communément désigné « tambour principal » ou « grand tambour », à la périphérie duquel sont montés des organes cardants,
• et un ou plusieurs cylindres successifs (notamment cylindre contre-tambour et/ou cylindre(s) peigneur(s) et/ou cylindre(s) condenseur(s)), qui d'une manière générale ont pour fonction de former sur leur périphérie un voile de fibres non-tissé à partir des fibres délivrées par le tambour de cardage ; dans la suite du présent texte, ces cylindres seront désignés généralement par « cylindres de formation d'un voile de fibres».

A card for the production of a nonwoven comprises in the usual manner:

• at least one rotary carding drum, still commonly referred to as a "main drum" or "large drum", on the periphery of which carding members are mounted,
• and one or more successive cylinders (in particular counter-drum cylinder and / or doffer cylinder (s) and / or condenser cylinder (s)), which in general have the function of forming on their periphery a web of nonwoven fibers from the fibers delivered by the carding drum; in the rest of this text, these cylinders will be generally referred to as "rolls of formation of a fiber web".

Several card output configurations using one or more successive cylinders for forming a fiber web are known to date. By way of non-exhaustive examples are given below the four most popular card output configurations.

A first known card output configuration, allowing the production of a parallel fiber web, uses, as forming rolls of the fiber web, one or more successive combing rollers.

A second known card output configuration, allowing the production of a scrambled fiber web, uses, as formation cylinders of the fiber web, a cylinder commonly referred to as a "counter-drum" followed by a doffer cylinder. .

A third known card output configuration, allowing the production of a condensed fiber web, uses, as formation cylinders of the fiber web, a doffer cylinder, followed by at least one condenser cylinder.

A fourth known card output configuration uses, as forming cylinders of the fiber web, a counter-drum cylinder followed by a doffer cylinder and a condenser cylinder.

The fiber web produced by means of the card must then be consolidated by any appropriate means (calendering, needling, ...) so as to form a consolidated nonwoven having a greater mechanical strength. More particularly, in the case of formation of multilayer nonwovens, this fiber veil is superimposed before consolidation with one or more other fiber webs which can, depending on the case, be produced in parallel by means of the same card (a frame comprising several outputs) or different cards. Also in the case of the formation of composite nonwovens, this fiber web can be superimposed with one or more other layers of fibers obtained by different techniques (layers of fibers such as "melt-blown", "spun", etc. )

To take up the fiber web formed at the end of the card, and to route it to the subsequent processing steps (in particular the consolidation step), it is customary to use a detaching cylinder associated with a conveyor belt, the detaching cylinder having as its function to take the fiber web from the periphery of the last sail-forming cylinder of the card outlet, and to transfer this fiber web to the conveyor belt. This type of solution is for example described in the requests for European patent EP 0704561 , EP 1 300 492 and EP 1318 217 of the plaintiff or in the application for European patent EP 1046731 .

In the present text, the term "detacher" is used to designate a cylinder whose peripheral lining is neutral (that is to say, unoriented) in contrast with the oriented lining of the sail-forming rolls (condenser, doffer, against -drum). Most of the time, it is a cylinder with an isosceles tip trim. It may also be a cylinder having longitudinal grooves around its entire periphery, a smooth cylinder, or a perforated cylinder having a fixed suction sector such as for example that described in FIG. French Patent No. 1,500,746 .

In the aforementioned European patent applications EP 0704561 , EP 1300492 and EP 1318217 of the applicant, the detaching cylinder [ EP 0704561 : cylinder (4) or (22) / EP 1300492 : cylinder (15a) or (15b) / EP 1318217 : Cylinder (31)] takes up the fiber web at the periphery of the last sail-forming cylinder of the card with a point of crawling downwards, the fiber web being thus taken up in the lower part by the detaching cylinder. The same is true of the solution in Figure 1 of the application for European patent EP 1046731 [detaching cylinder (4)].

Conversely, in the solution of FIG. 2 of the abovementioned European patent application EP 1046731 , the detaching cylinder [ EP 1046731 FIG. 2 - cylinder (4) or (4a)] takes up the fiber web at the periphery of the last web-forming cylinder of the card with a point of upward curl, the fiber web thus being taken up in the upper part. by the detaching cylinder.

The card configuration for the formation of a condensed fiber web illustrated in Figure 2 of the application for European patent EP 1046731 has the advantage of implementing a single condenser cylinder [cylinder (22) or (24)] at the card outlet, and is therefore more advantageous for example than the card configuration of the request for European patent EP 1 300492 which implements two successive condenser cylinders [FIG. 1 - successive condenser cylinders (12a) / 13 (a) or condenser cylinders (12b) / 13b)].

On the other hand, the plaintiff has found that a carding output configuration of the type shown in FIG. 2 of the application for the European patent EP 1046731 , that is to say with detaching cylinder ensuring the recovery of the fibrous web with a cusp up, had the disadvantage of causing the formation in the web of bubbles visible to the naked eye, and detrimental to the quality of the fibrous veil produced. A bubble is a point zone of the veil in which the fibers are locally released and form a kind of blister on the surface of the veil. This phenomenon of bubble formation is particularly preponderant in the case of the formation of condensed sails, but is also likely to occur with parallel sails or with scrambled sails. The increase in production speed is also accompanied by an increase in the presence of bubbles in the veil.

OBJECTIVE OF THE INVENTION

The present invention aims to improve the quality of a web of fibers produced by means of a card, and taken at the card outlet by a detaching cylinder with a point of upward curl, and more particularly aims at reducing the risks of bubble formation in such a veil.

SUMMARY OF THE INVENTION

The aforementioned objective is achieved by the invention which firstly relates to a card for the formation of at least one fiber web, which is of the type shown in FIG. European patent EP 1 046 731 in that it comprises, on the one hand, a detaching cylinder whose function is to take off on its periphery and with a point of upward twisting, the web of fibers previously formed, and secondly a transport surface of the fiber web, positioned downstream of the detaching cylinder.

Characteristically according to the invention, between the detaching cylinder and the conveying surface is interposed a suction rotary transfer member whose function is to transfer the fiber webs between the detaching cylinder and the transport surface by holding the web of fibers.

The suction of the transfer member is adjusted so as to reduce, and preferably so as to avoid, the formation of bubbles in the fiber web.

• la carde comprend un cylindre condenseur positionné immédiatement en amont du cylindre détacheur ;
• la carde comporte un cylindre peigneur positionné immédiatement en amont du cylindre condenseur ;
• la carde comporte un tambour de cardage principal, et entre le tambour de cardage et le cylindre détacheur, un ou plusieurs cylindres successifs de formation de voile, dont un unique cylindre condenseur ;
• la carde comporte un tambour de cardage principal, et une succession de cylindres qui est interposée entre le tambour de cardage principal et le cylindre détacheur, et qui est choisie parmi le groupe suivant : cylindre peigneur/cylindre condenseur, ou cylindre transfert accumulateur/cylindre peigneur /premier cylindre condenseur/deuxième cylindre condenseur, ou cylindre transfert accumulateur/cylindre peigneur ;
• l'organe de transfert aspirant est un cylindre ;
• l'organe de transfert aspirant est une bande de transport ;
• le cylindre détacheur est un cylindre aspirant.

More particularly, and in a nonlimiting and non-exhaustive manner of the invention, the card has the following additional technical characteristics, taken separately or in combination:

• the card comprises a condenser cylinder positioned immediately upstream of the detaching cylinder;
• the card has a doffer cylinder positioned immediately upstream of the condenser cylinder;
• the card has a main carding drum, and between the carding drum and the detaching cylinder, one or more successive formation cylinders, including a single condenser cylinder;
• the card has a main carding drum, and a series of cylinders which is interposed between the main carding drum and the detaching cylinder, and which is selected from the following group: dancer cylinder / condenser cylinder, or accumulator transfer cylinder / dancer cylinder / first condenser cylinder / second condenser cylinder, or accumulator transfer cylinder / doffer cylinder;
• the suction transfer member is a cylinder;
• the suction transfer member is a conveyor belt;
• the detaching cylinder is a suction cylinder.

Another object of the invention is a training method a carded fiber web. This process is known, in particular by FIG. 2 of the application for European patent EP 1046731 in that a web of fibers is formed by means of one or more successive cylinders of a card, this fiber web is detached from the periphery of the last sail-forming cylinder by means of a detaching cylinder and with a cusp up, and the fiber web is deposited on a transport surface.

Typically according to the invention, the fiber web is transferred between the detaching roll and the transport surface by holding it against the surface of a rotary transfer member by suction.

Preferably, the detaching roll is rotated with a circumferential speed of at least 130 m / min and more preferably still greater than or equal to 150 m / min.

BRIEF DESCRIPTION OF THE FIGURES

• la figure 1 représente une première variante de réalisation d'une carde de l'invention à deux sorties, chaque sortie de la carde comportant successivement comme cylindres de formation de voile : un cylindre peigneur et un unique cylindre condenseur ;
• la figure 2 représente une deuxième variante de réalisation d'une carde de l'invention à deux sorties, chaque sortie de la carde comportant successivement comme cylindres de formation de voile : un cylindre transfert accumulateur (commun aux deux sorties), un cylindre peigneur et deux cylindres condenseur ;
• la figure 3 représente une troisième variante de réalisation d'une carde de l'invention à deux sorties, chaque sortie de la carde comportant en guise de cylindres de formation de voile : un cylindre transfert accumulateur (commun aux deux sorties), et un cylindre peigneur ;
• la figure 4 représente une quatrième variante de réalisation d'une carde de l'invention, dont la sortie comporte les mêmes cylindres que la variante de la figure 1, mais pour laquelle la position du cylindre de transfert aspirant a été optimisée, dans le but de réduire le trajet du voile de fibres à la périphérie du cylindre détacheur ;
• la figure 5 représente une cinquième variante de réalisation d'une carde de l'invention mettant en oeuvre un cylindre détacheur aspirant, et
• les figures 6 et 7 représentent respectivement une sixième et une septième variante de réalisation d'une carde de l'invention, mettant en oeuvre une bande transport aspirante en guise d'organe de transfert rotatif.

Other characteristics and advantages of the invention will emerge more clearly on reading the following detailed description of several preferred examples of card reclasation according to the invention, which detailed description is given by way of non-limiting example and non-exhaustive of the invention, and with reference to the accompanying drawings in which:

• 1 shows a first embodiment of a card of the invention with two outputs, each output of the card having successively as forming sail cylinders: a doffer cylinder and a single condenser cylinder;
• FIG. 2 represents a second variant embodiment of a card of the invention with two outputs, each output of the card comprising successively as sail formation cylinders: an accumulator transfer cylinder (common to the two outputs), a doffer cylinder and two condenser cylinders;
• FIG. 3 represents a third variant embodiment of a card of the invention with two outputs, each output of the card comprising, by way of formation cylinders, a cylinder accumulator transfer (common to both outputs), and a doffer cylinder;
• FIG. 4 represents a fourth variant embodiment of a card of the invention, the output of which has the same cylinders as the variant of FIG. 1, but for which the position of the suction transfer cylinder has been optimized for the purpose to reduce the path of the fiber web at the periphery of the detaching roll;
• FIG. 5 represents a fifth variant embodiment of a card of the invention implementing a suction detaching cylinder, and
• Figures 6 and 7 show respectively a sixth and a seventh embodiment of a card of the invention, implementing a suction conveyor belt as a rotary transfer member.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a first embodiment of a card which conforms to the invention and which, in the particular example illustrated, comprises two upper and lower outputs for the parallel production of two fibrous webs V1. and V2. In a simplified variant, the card could have only one output. This card comprises in the usual manner a main carding drum 1 (commonly called "large drum") which allows the parallelization of the fibers cooperating in a manner known per se with carding members mounted at the periphery of the carding drum. In Figure 1, for the sake of simplification, these carding members, as well as all other elements of the card which are positioned upstream of the carding drum 1 and which are usual, have not been shown. For a complete description of these elements (carding members and card elements upstream of the carding drum 1), reference should be made to the description of the request for European patent EP 1318217 of the plaintiff.

In the particular example of Figure 1, the two outputs lower and upper of the card are identical, the two fiber webs V1 and V2 produced being similar. In another variant, the two outputs could have different configurations.

Each output of the card of FIG. 1 comprises successively from the carding drum 1: a doffer cylinder 2, a condenser cylinder 3, a detacher cylinder 4 with isosceles tips 4a, a suction transfer cylinder 5, and a conveyor belt 6 .

The doffer cylinder 2 and the condenser cylinder 3 constitute the formation cylinders of the fibrous web (V1 or V2). In the usual way, these cylinders make it possible to form a condensed fibrous web (V1 or V2), having a better isotropy of its mechanical properties, compared for example with a parallel web. For this purpose, the doffer rollers 2 and condenser 3 comprise, in known manner, an oriented peripheral lining 2a, 3a whose teeth are inclined in the direction opposite to the rotation of these rolls; the condenser cylinder 3 is driven in the opposite direction of the doffer cylinder 2, and with a circumferential speed much lower than that of the doffer cylinder 2.

In operation of the card, the detaching cylinder 4 is rotated in the same direction as the condenser cylinder 3 and with a circumferential speed at least equal to and preferably greater than that of the condenser cylinder 3, and removes the condensed web (V1 or V2) of the periphery of the condenser cylinder 3. More specifically, the fibrous web arrives in the sampling zone from above the condensing cylinder 3, and is taken up by the detaching cylinder 4 with a cusp P upwards; in other words, the detaching roll 4, which is driven in rotation in the same direction as the last sail-forming roll (that is to say, the condenser roll 3 in the example of FIG. fibrous veil on its periphery to route it upwards.

The fibrous web is conveyed to the periphery of the detaching cylinder 4 to the suction transfer cylinder 5.

The suction transfer cylinder has a cylindrical envelope 5a which is perforated over its entire surface and which is rotatable, and a fixed suction chamber defined by two fixed inner walls 5c. This suction chamber 5b extends over the entire length of the cylindrical envelope 5a and on a limited sector of this envelope (suction sector AB). This chamber 5b is connected to a fan or the like allowing the suction chamber 5b to be depressurized, thereby creating through the cylindrical envelope 5a and on the suction sector AB a sufficient suction to press the fibrous web on the surface of the transfer cylinder 5.

In operation, the perforated cylindrical casing 5a of the transfer cylinder 5 is rotated, for example by means of an individual motor, in the opposite direction of the detaching cylinder 4. The circumferential speed of the cylindrical casing 5a of the cylinder of transfer 5 may be equal to or greater than the circumferential speed of the detaching roll 4, or may be less than the circumferential speed of the detaching roll 4. The fibrous haze is removed, without a cusp, from the periphery of the detaching roll by the transfer cylinder 5, and is conveyed by the sucking transfer cylinder 5 to the surface of the transport belt 6. Between the detaching cylinder 4 and the transport belt 6, the fibrous web is constantly maintained by suction against the cylindrical casing 5a of the transfer cylinder 5.

Downstream of the suction sector (AB) of the transfer cylinder 5, the fibrous web is deposited on the surface of the conveyor belt 6. Preferably, but optionally according to the invention, the conveyor belt is permeable to air, and to help the recovery of the fibrous web by the conveyor belt 6, the fibrous web is locally aspirated through the conveyor belt 6, and over the entire width of this strip, by means of a box of 7. For a detailed description of this aspiration, one skilled in the art will refer to the description of the application for European patent EP 0 704 561 of the plaintiff. The fibrous web is thus pressed by suction against the conveyor belt 6. The conveyor belt 6 is driven at a linear speed which according to the case may be greater than or equal to the circumferential speed of the transfer cylinder 5, or on the contrary lower than the circumferential speed of the transfer cylinder 5 (condensation of the web during its transfer on the conveyor belt 6).

Table I below corresponds to a nonlimiting example of operation of the card just described, for the parallel production of two substantially identical condensed fiber webs V1 and V2 formed from a fiber mixture. polypropylene and viscose fibers of average length of the order of 38mm. <u> Table I </ u>: organs Large drum (1) Peindre Cylinder (2) Condenser Cylinder (3) Cylinder Detacher (4) Transfer Cylinder (5) Transport band (6) Weight of the veil (gr / m ² ) / 8.5 15.6 / / / Circumferential (or linear) speed (m / min) 1000-1560 220 120 130-200 130-200 150-200

The cylindrical envelope 5a of the transfer cylinder 5 was perforated with a multitude of identical holes regularly distributed over the entire surface of the envelope, and with a perforation rate (that is to say the ratio between the total area perforations and the total surface of the cylindrical envelope) of between 25% and 35%. In operation, the air velocities through the perforations of the cylindrical envelope 5a were between 0.5m / s and 3m / s. The invention is not limited to these particular parameters of suction which are given for information only. It is particularly for those skilled in the art to adapt these parameters on a case-by-case basis, and in particular to adjust the power of the suction so that it is sufficient for the fiber web to be transferred. without bubble formation in the veil.

Comparative tests were carried out with the card of FIG. 1, with implementation and without implementation of a suction at sector AB of the transfer cylinder 5. These tests made it possible to observe that in the absence of suction, the fiber web (V1 or V2) contained bubbles visible to the naked eye and forming randomly in the web. It has furthermore been found that the formation of bubbles increases with the speed of production. Typically, in the tests carried out, and in a nonlimiting manner of the invention, it was found that bubbles were systematically formed in the fibrous web from production speeds of greater than 150 m / min (circumferential speeds of the stripper cylinder and transfer cylinder).

Conversely, and surprisingly, by using suction on the transfer cylinder 5 according to the invention, it is capable of producing, especially at high speed (typically greater than 150 m / min) a fibrous web. quality, free of bubbles.

A plausible explanation (found a posteriori) of this advantageous result of the invention would be the following. In the absence of suction on the transfer cylinder 5, the fibers of the web, during the course of the web between the detaching cylinder 4 and the transport belt 6, are not maintained mechanically, and therefore tend to relax and to relax uncontrollably, which would cause the formation of bubbles. This loosening phenomenon would be increased in the case of a condensed web, in which the fibers of the web were compressed in the direction of their length during the condensation operation by the condenser cylinder 3, and therefore naturally tend to relax when released mechanically. In the context of the invention, the suction at the transfer cylinder would physically maintain in place the fibers of the veil during its transfer to the transport belt, and incidentally reduce the phenomenon of relaxation of the fibers sufficiently to avoid the formation of bubbles. The plaintiff however, is not bound by this explanation.

It has also been found that the implementation of the suction at the transfer cylinder advantageously makes it possible to increase the adjustment range of the operating speed of the detaching cylinder 4, for given operating speeds of the doffer 2 and condenser cylinders. 3.

• par la mise en oeuvre d'un cylindre transfert accumulateur T additionnel interposé entre le tambour de cardage 1, et les deux cylindres peigneurs ; pour une meilleure compréhension de la structure et de la fonction de ce cylindre transfert accumulateur T, on se référera à la demande de brevet européen EP 1 318 217 de la demanderesse, et en particulier aux explications données sur la structure et le fonctionnement du cylindre référencé (3i) sur la figure 1 de cette publication ;
• par la mise en oeuvre d'un cylindre condenseur additionnel 3' entre le cylindre peigneur 2 et le cylindre condenseur 3.

FIG. 2 shows another alternative embodiment of a card according to the invention, which differs from the variant of FIG. 1:

• by the implementation of an additional accumulator transfer cylinder T interposed between the carding drum 1, and the two combing rollers; for a better understanding of the structure and the function of this accumulator transfer cylinder T, reference will be made to the request for European patent EP 1 318 217 of the applicant, and in particular the explanations given on the structure and operation of the cylinder referenced (3i) in Figure 1 of this publication;
• by the implementation of an additional condenser cylinder 3 'between the doffer cylinder 2 and the condenser cylinder 3.

FIG. 3 shows another alternative embodiment of a card according to the invention, which is different from the variant of FIG. 2, by the implementation on each output only of a doffer cylinder 2, the condenser cylinders having been removed. The detaching cylinder 4 directly takes up the fibrous web at the periphery of the doffer cylinder 2, with a cusp P upwards. This card makes it possible to produce two sails of parallel fibers at the exit.

The variant of FIG. 4 is similar to that of FIG. 1 (in this FIG. 4, the carding drum 1 has not been shown), and differs by an optimization of the position of the suction transfer cylinder 5 by relative to FIG. 1, the suction cylinder of the variant of FIG. 4 is closer to the last formation cylinder of the web (condenser cylinder 3), and the path of the web between the last forming cylinder of the web (condenser cylinder 3) and the conveyor belt 6 is shorter (especially at the periphery of the detacher cylinder 4), which further reduces the risk of loosening of the fibers.

In the variant of Figure 5, the detaching cylinder 4 is preferably a suction cylinder so that the fiber web at the output of the doffer cylinder is constantly maintained by suction at the periphery of the detacher cylinder 4, to the recovery zone by the suction transfer cylinder 5. This avoids the risk of loosening the fibers of the web at the periphery of the detaching cylinder 4.

In the variant of FIG. 6, the card has three identical sail-forming outputs (combo cylinder 2 / condenser cylinder 3 / detacher cylinder 4) and a single rotary transfer member 5 'common to the three detaching cylinders 4. This member 5 'suction transfer conveyor comprises a conveying belt 5'a inclined and permeable to air, and suction through and across the width of said strip is implemented by means of suction boxes 5'b. This aspiration is carried out over the entire region of the conveyor belt which extends from the upper detachment cylinder 4 to the recovery zone by the conveyor belt 6. In operation, the three fiber webs V1, V2 , V3 are superimposed on the surface of the suction strip 5'a, being constantly held by suction on the surface of this band 5'a, then are deposited on the conveyor belt 6.

The variant of FIG. 7 is different from that of FIG. 6 by the orientation of the conveyor belt 6, and by the implementation of a suction cylinder 8, which is positioned in the junction zone between the conveyor belts. transport 5'a and 6, and which is used to transfer the superimposed webs V1, V2 and V3 between the conveyor belt 5'a and the conveyor belt 6.

In another variant (not shown), the conveyor belt 6 could be provided to have bidirectional operation, and allow the routing of the fiber web or sails to two positions of different consolidation depending on the drive direction of the conveyor belt.

The invention is not limited to the particular embodiments which have been described with reference to the appended figures, but is determined by the content of the claims. In particular, the invention can be applied to any card output configuration in which the detaching cylinder removes the previously formed fiber web on its periphery, with a cusp point (P) upwards. The sail forming rollers arranged upstream of the detaching roll are not limited to the types of rolls of the accompanying figures (ie, doffer, condenser or transfer). The invention can also be applied to a card having a counter drum cylinder as a sail forming cylinder.

Claims (10)

1. A card for forming at least one fibre web (V1, V2 or V3) and comprising a takeoff cylinder (4) adapted for picking up, from the circumference thereof and with a turning-up point (P), the previously formed fibre web, and a fibre web conveying surface (6) positioned downstream from the takeoff cylinder (4), characterized in that there is included between the takeoff cylinder (4) and the conveying surface (6), a sucking rotating transfer member (5; 5')whose function is to transfer the fibre web between the takeoff cylinder (4) and the conveying surface (6) while maintaining the fibre web by suction.
2. A card according to claim 1, characterized in that it comprises a condensing cylinder (3) positioned right upstream from the takeoff cylinder (4).
3. A card according to claim 2, characterized in that it comprises a doffer cylinder (2) positioned right upstream from the condensing cylinder (3).
4. A card according to claim 1, characterized in that it comprises a main carding drum (1) and, between the carding drum (1) and the takeoff cylinder (4), one or more successive web forming cylinders, including one single condensing cylinder (3).
5. A card according to claim 1, characterized in that it comprises a main carding drum (1) and a serie of cylinders being included between the main carding drum (1) and the takeoff cylinder (4) and being selected amongst the following group : either a doffer cylinder (2)/condensing cylinder (3) or an accumulating transfer cylinder (T)/doffer cylinder (2)/first condensing cylinder (3')/second condensing cylinder (3) or an accumulating transfer cylinder (T)/doffer cylinder (2).
6. A card according to any of claims 1 to 5, characterized in that the sucking transfer member is a cylinder (5).
7. A card according to any of claims 1 to 5, characterized in that the sucking transfer member is a conveying belt (5').
8. A card according to any of claims 1 to 7, characterized in that the takeoff cylinder (4) is a sucking cylinder.
9. A method for forming a fibre web comprising the steps of forming a fibre web (V1, V2 or V3) by means of one or more successive cylinders of a card, takeoff such fibre web from the circumference of the last web forming cylinder, by means of a takeoff cylinder (4) and with a turning-up point (P) and laying down the fibre web (V1, V2 or V3) onto a conveying surface (6), characterized in that the fibre web (V1, V2 or V3) is conveyed between the takeoff cylinder and the conveying surface while being maintained by suction against the surface of a rotating transfer member (5; 5').
10. A method according to claim 9, characterized in that the takeoff cylinder (4) is driven into rotation with a circumferential speed at least equal to 130 m/min and preferably higher or equal to 150 m/min.

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