EP1676942A2 - Method for recycling non-processed fibres in a carding machine and a carding machine equipped with means for carrying out the method - Google Patents

Abstract

The circulation is carried at the top and near of the carding system (3) in direction of the upstream of the carding cylinder. An independent claim is also included for a card.

Description

Technical area

The present invention relates to the textile field and relates to a new solution for recycling fibers not worked in a card. The invention is preferably applied to the recycling of fibers not worked in a card equipped with group (s) card (s) roller (s).

Previous Art

A card comprises in the usual manner at least one rotary carding cylinder, still commonly referred to as a main drum or a large drum, on the periphery of which carding members are mounted. In operation, the fibers transported at the periphery of the carding cylinder are worked by the combined actions of the carding members and the peripheral lining of the carding cylinder (carding operation of the fibers).

There are various types of carding members, the main ones being: roller carding units, carding mats, carding plate fixed carding members.

A roller carding unit generally comprises a roller commonly called "worker" associated with a "stripper" roller, sometimes sometimes called "sweeper". In practice, a carding cylinder is equipped on its periphery with several successive carding groups with rollers. Carding roller units are widely used in cardes for the production of nonwoven webs.

A card mat includes a conveyor belt which is mounted near the carding cylinder and which, in part of its path, partially follows the curve of the carding cylinder. This band is equipped with carding fittings adapted to cooperate with the peripheral lining of the carding cylinder. This type of carding organ is basically used in cotton cardes.

The fixed carding members are for example in the form of a fixed fairing (also commonly called "carding plate") having a plurality of carding points fixed at the periphery of the carding cylinder.

Usually, in a conventional card structure, at each rotation of the carding cylinder, a more or less weak portion of the fibers at the periphery of the carding cylinder is taken up, at a point situated downstream of the carding members, by one or several cylinders positioned downstream of the carding cylinder, while the residual portion of the fibers at the periphery of the carding cylinder is recycled by the carding cylinder to the carding members.

In the simplest structure, the card has a single carding cylinder. In more complex structures, the card may comprise several successive carding cylinders, each carding cylinder being equipped on its periphery with carding members for working the fibers.

In cards equipped with group (s) card (s) of the roller type, it is observed in operation a fiber ejection on the carding groups. These flying fibers accumulate uncontrollably in the form of piles of fibers that are not properly worked and that disturb the operation of the card, in particular by polluting the textile product, for example the nonwoven web, produced at the exit of the card. This ejection of the fibers, and in particular the amount of flying fibers ejected and unworked, depends on several parameters, including: the coupling strength of the carding cylinder lining (-this gripping power being also variable in the time as a function of the wear of the lining), the crimp of the fibers, the coefficient of friction of fiber / fiber or fiber / metal, the speed of rotation of the rollers of the carding group.

There is therefore an interest in finding a technical solution that allows to limit, and preferably to eliminate, the disadvantages arising from the ejection of flying fibers on carding roller units of a card.

With the other aforementioned types of carding members (carding mats, carding plates), it is also observed during operation of the card the presence of flying fibers. The generation of flying fibers is in this case much less important than with carding roller groups, but may be sufficient if necessary to disrupt the correct operation of the card.

Objective of the invention

The main object of the present invention is to propose a new technical solution which improves the operation of a card in that it makes it possible to overcome the drawbacks arising from the presence of non-worked flying fibers which escape from the carding members of a card. card.

A more particular object of the invention is to propose a new technical solution to improve the operation of a card equipped with group (s) card (s) roller (s).

Summary of the invention

The aforementioned main objective is achieved by the invention which relates to a method of recycling fibers in a card comprising at least one carding cylinder and carding members mounted at the periphery of the carding cylinder.

Characteristically according to the invention, the card has a covering covering the carding members, and a recirculating air stream is created which circulates under this cowling above and close to the carding members, so as to bring back the non-worked fibers. upstream of the carding cylinder.

Another object of the invention is a card comprising at least one carding cylinder and carding members mounted at the periphery of the carding cylinder.

Characteristically according to the invention, the card comprises means for recycling the unworked fibers, which comprise a cowling covering the carding members, and which are designed to create a flow of air flowing under this cowling over and near the carding members. carding members in the upstream direction of the carding cylinder.

In the present text, the terms "upstream" and "downstream" are defined with respect to the direction of progression of the fibers in the card, that is to say in other words with respect to the direction of rotation of the carding cylinders of the card.

Preferably, but not exclusively, the invention is applied to a card whose carding members comprise one or more roller carding units.

Brief description of the drawings

• la figure 1 est une représentation schématique vue de côté d'une carde non-tissé conforme à une première variante de réalisation,
• la figure 2 est une perspective de la carde de la figure 1,
• la figure 3 est une vue de dessus de la carde de la figure 1, et
• la figure 4 est une vue latérale de la carde dans un plan perpendiculaire au plan de la figure 1,
• et la figure 5 est une représentation schématique vue de côté d'une carde non-tissé conforme à une deuxième variante de réalisation.

Other characteristics and advantages of the invention will appear more clearly on reading the following detailed description of two preferred embodiments of the invention, applied to a nonwoven card equipped with roller carding units, which description is given by way of non-limiting and non-exhaustive example of the invention, and with reference to the appended drawings in which:

• FIG. 1 is a schematic side view of a nonwoven card according to a first embodiment variant,
• FIG. 2 is a perspective of the card of FIG.
• FIG. 3 is a view from above of the card of FIG. 1, and
• FIG. 4 is a side view of the card in a plane perpendicular to the plane of FIG. 1,
• and Figure 5 is a schematic side view of a nonwoven card according to a second embodiment.

detailed description

FIG. 1 shows a double exit card for producing nonwovens, and more particularly nonwovens based on synthetic fibers of the polypropylene, polyethylene, ... and / or fiber type. natural cotton type, and / or viscose type artificial fibers, ...

The card of FIG. 1 comprises an input E of a card equipped with means 1 for supplying fibers which are constituted in the illustrated example of a trough 1a, a food roll 1b, and a breaker cylinder 1c. In the usual way, in operation, a sheet of fibers is introduced continuously (by means not shown) at the entrance E of the card between the trough 1a and the food roll 1b.

From this layer of fibers, the breaker cylinder 1c feeds into fibers a first rotary carding cylinder 2, which is more commonly known as a front end, and which is equipped on its periphery with a carding insert (in the form of spikes). or any other equivalent means) allowing it to take up the fibers of the periphery of the breaker cylinder. In the usual way, several carding groups 3 with successive rollers are mounted at the periphery and in the upper part of the front end 2. Each carding unit 3 is composed of a sweeping roll 3a and a working roll 3b. Each carding unit 3 cooperates with the front end 2 and has the function of working the fibers taken in the lining of the front end 2 so as to individualize and parallelize them. Carding groups 3 could be replaced by any other equivalent means fulfilling the same function.

Downstream of the limber 2, the card has a transfer cylinder 4, also commonly called "communicator", which allows to take all the fibers at the periphery of the front limb 2 and transfer them to a second carding cylinder 5, still commonly called "big drum". In a manner known per se, this second carding cylinder 5 is coated with carding lining and comparable to the first carding cylinder 2 cooperates with roller carding units 3.

Downstream of the second carding cylinder 5, the card has two lower and upper outputs, each carding outlet comprising for example a doffer cylinder 6, a detaching cylinder 7, and a strip of transport 8.

All of the aforementioned rolls and rollers of the card is supported on the ground by a support frame 9.

In operation of the card, the fibers are worked and progress in the card at the periphery of the rolls 2, 4 and 5, to the output cylinders 6 (direction of progression of the worked fibers shown schematically by the arrow D in FIG. 1) .

With reference to FIGS. 1 and 2, the card is equipped with a covering means 10, which in the illustrated example comprises a curved top wall 10a and two substantially planar and vertical side walls 10b. This covering 10 may, depending on the case, be supported on the ground by the carrier frame 9 or be supported on the ground by separate support means of the carrier frame 9.

With reference to FIGS. 3 and 4, the card is also equipped with substantially vertical lateral flanges 12 which are supported by the frame 9 and are mounted on either side of the rolls of the card. These lateral flanges 12 form with the upper wall 10a of the covering 10 an upper cowling 13, which covers the carding cylinders 2 and 5 of the card in the upper part, the carding groups 3 with rollers being entirely housed inside this cowling. . For the sake of simplification, the lateral flanges 12 have not been shown in FIGS. 1 and 2, and are only shown in FIGS. 3 and 4.

In the example shown, the cowling 13 covers the card from its input E (including the fiber supply means 1a, 1b and 1c) to the output rollers 6. In another embodiment, the The cowling 13 could stop at the last carding group 3 of the card, the important thing being that the cowling 13 covers the carding groups 3 that is to be protected by a recycling air flow of the non-worked fibers. The cowling 13 delimits above the carding groups 3 of the card a corridor 13a of width L (Figure 4) substantially corresponding to the length of the carding cylinders 2 and 5. This corridor 13a allows channel the recirculating air stream to the right of the carding rolls 2 and 5, and close to the carding groups 3.

Referring to Figure 1, the downstream side face 10c of the cover 10 is open such that an air intake A under the cowling 13 is formed downstream of the last carding unit 3 of the carding cylinder 5. This admission d Air A extends over the entire width (L) of the cowling 13 (Figure 4).

In contrast, the upstream end 10d of the cover 10 is equipped with a suction box 11 comprising an internal air duct 11a which extends substantially over the entire width of the card, and which communicates with air intake openings A 'formed in a front wall 11b of the suction box 11. These air intake openings A' open below the cowling 13 and are distributed over the width (L) of the In another variant, all or part of the intake openings A 'could be replaced by a longitudinal slot or equivalent.

At one of its two ends, the suction box 11 has a discharge opening A "which communicates with the inner conduit 11a, and which is connected to a fan (not shown).

In operation of the card, the aforementioned fan is turned on, and sucks continuously under the cowling 13 of the air which penetrates inside the inner pipe 11a of the suction box 11 via the inlet openings A ', and which is discharged through the discharge opening A' towards the intake of the fan.This air is discharged continuously by the fan in the open air outside the cowling 13. This suction generates the circulation, under the cowling 13 and over substantially the entire length of the carding rollers [width (L)], a stream of air recycling fibers which is shown schematically in the figures attached by arrows F. This flow of recirculation air F circulates under the cowling 13 forcibly and continuously near the carding groups 3, from the inlet A of the cowling 13 downstream of the main carding roll 5 to the suction box 11 located at the cardboard inlet E, upstream of the carding cylinder 2. This recirculating air flow F is therefore oriented in the direction opposite to the direction D of progression of the fibers worked at the periphery of the rolls. .

In operation of the card, the non-worked flying fibers which are ejected from the rolls of the carding groups 3 are driven under the cowling 13 by the recirculating air flow F to the inlet E of the card, upstream of the first carding cylinder 2. These fibers are then taken up by the feed means 1 at the input of the card and are reintroduced, at the periphery of the first carding cylinder 2, by the breaker cylinder 1c, with the other fibers from the entrance tablecloth. These fibers are thus advantageously recycled into the card, and no longer interfere with the operation of the card, in contrast with a card that would be devoid of the recirculation airflow F.

It is up to the person skilled in the art to judiciously adjust the power of the recirculating air flow F on the one hand so that it is sufficiently effective to drive the unworked fibers to the inlet E of the carde, but on the other hand so that it is not too powerful so as not to disturb the path of the fibers entrained at the periphery of the rolls of the card.

In the particular embodiment variant which has just been described, the card is equipped with a single upstream suction box 11 for the creation of the recirculating air flow F. This is not however a limitation of the invention. . In another alternative embodiment, it is possible to provide several suction boxes, and for example in the embodiment of Figures 1 to 4 attached, an additional suction box intermediate upstream of the carding cylinder 5, and for example positioned above the carding cylinder 2.

FIG. 5 shows another embodiment of the invention in which, for the creation of the recirculating air flow F, the card is equipped, in addition to the suction box 11, with two boxes. additional suction 11 'and 11 "which are mounted on the cowling 13, downstream of the box 11. More particularly, in this embodiment, the suction box 11' is positioned in the area between the cylinder of 5 and the drawbar 2, the suction box 11 "is positioned downstream of the main carding cylinder 5. In a manner comparable to that described for the suction box 11, the boxes of 11 'and 11 "extend, in the direction perpendicular to the plane of Figure 5, preferably substantially over the entire width of the card (that is to say the length of the rolls of the card).

The implementation of a recycling stream F of the invention is particularly advantageous for cards which are equipped with group (s) card (s) roller (s) as the card of the accompanying figures, because the phenomenon of fiber ejection Unworked is important for this type of card. Nevertheless, the invention is not limited to this type of card, but can also be applied to cards equipped with other types of carding members (fixed or mobile) for which the amount of non-worked flying fibers is certainly less important, but not negligible.

Claims (9)

Process for recycling fibers in a card comprising at least one carding cylinder (2; 5) and carding members (3) mounted on the periphery of the carding cylinder, characterized in that the card has a covering (13) covering the card carding members (3) of the card, and in that a recirculating air stream (F) is created which circulates under this cowling (13) above and close to the carding members (3) so as to reduce the fibers not worked upstream of the carding cylinder. Process according to Claim 1, characterized in that the recirculating air stream (F) is created by suction. Process according to Claim 1 or 2, characterized in that, by means of the recirculating air stream (F), the unworked fibers are brought back to the inlet (E) of the card and these fibers are reintroduced to the periphery of a carding cylinder (2) of the card. Method according to one of Claims 1 to 3, characterized in that at least one of the carding members is a roller carding unit (3). Carding machine comprising at least one carding cylinder and carding members mounted on the periphery of the carding cylinder, characterized in that it comprises means (10, 11, 12, 13) for recycling the unworked fibers, which comprise a rollover (13) covering the carding members (3) of the card, and which are designed to create a flow of air (F) flowing under this cowling (13) above and near the carding members in the upstream direction of the card carding cylinder. Card according to Claim 5, characterized in that at least one of the carding members is a roller carding unit (3). Card according to one of Claims 5 or 6, characterized in that the recycling means for the non-worked fibers comprise suction means (11). Card according to Claim 7, characterized in that the suction means are positioned at the entrance (E) of the card. Card according to one of Claims 5 to 8, characterized in that the recycling means for the non-worked fibers make it possible to generate a recirculating air flow (F) circulating under the hood (13), since the downstream of the last carding cylinder (5) to the entrance (E) of the card.

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