EP0083897A1 - Method, device and plant for removing a fibre sliver after its wet-treatment - Google Patents

Abstract

1. Process for taking up a tow of fibrous material having little or no cohesion downstream of said material wet-process station, characterized by the exclusive use of a single pneumatic means (1) for twisting and drawing said tow (13) of material, said means consisting in directing onto the tow at least one air jet oriented substantially tangentially with respect to the tow and substantially inclined with respect to the direction of forward movement thereof.

Description

The invention relates to a method for taking up a strand of fibrous material or twist yarn having little or no cohesion downstream of a wet treatment station for said material.

We know the importance assumed by spinning processes, not using real twist as a means of interfiber cohesion. Thus it has been proposed, in particular by French Patent No. 1,530,182, a process for spinning wet flax, in which the inter-fiber cohesion is ensured, on the one hand, by the wet state of the fiber and, on the other hand, by a false twist device before winding.

Also known from French Patent No. 70 43 555 in the name of the applicants is a method of gluing a wick, according to which it is the glue which ensures, once dry, the inter-fiber cohesion.

However satisfactory the installations implementing the known methods may have been, their development has, however, encountered a certain number of obstacles. In particular, all using positive traction by mechanical pinching of the locks, even though the cohesion was still very low (before drying the glue, for example), it proved difficult to reach attractive production speeds without breakage of wicks.

Furthermore, and in particular in the case of a sizing installation, the traction members very quickly become clogged with the deposit of glue which is made therein continuously.

The object of the present invention is to provide a method for recovering the wick free from the aforementioned drawbacks.

This object is achieved, in accordance with the invention, by the exclusive use of a single pneumatic Dean for twisting and towing said wick of material, by which means one directs at least one jet of air oriented sensibly in the wick. tangentially with respect to the drill bit and substantially inclined with respect to the direction of advance thereof.

Advantageously, the pneumatic torsion-traction means are used, which by its air jet "pushes" the wick with a certain power, to pro throw the wick on a transfer device to a downstream treatment station, such as a drying station.

The invention allows automatic threading at the start of spinning and, on the other hand, results in less electrical energy consumption than with two separate means for traction and torsion.

The invention also relates to a wick take-up system applying the method of the invention and comprising a single pneumatic means for twisting and pulling said wick being constituted by a duct for passing the wick into which a tangential compressed air supply opens. with respect to said conduit and substantially inclined with respect to the direction of advance thereof.

The duct can be drilled in a block, the upper part of which is optionally provided with two gutters joining a water supply point, drop by drop, respectively at the inlet and at the outlet of the scroll duct, at self-cleaning purposes if necessary.

• - de véhiculer la matière sans pincement et donc sans risque d'encrassement d'organes mécaniques d'entraînement de la mèche ;
• - de donner une forte cohésion temporaire à la mèche ;
• - de lui donner une forme ronde, notamment en diminuant la pilosité du fil ; la structure superficielle conférée est telle que le fil acquiert une ténacité définitive relativement élevée et une bonne compacité après séchage ;
• - d'autoréguler la tension de la matière fibreuse , plus sûrement que par une traction mécanique ;
• - de décoller la matière au sortir du dispositif de traitement humide, en rassemblant bien les fibres marginales, ce qui constitue un point particulièrement critique des installations d'encollage ;
• - de réaliser un auto-exprimage pouvant at- teindre 80 à 100 Z dans le cas d'une installation de filature au mouillé, auto-exprimage dû à la torsion et à l'effet de séchage provoqué par le courant d'air comprimé qui pulvérise les gouttelettes d'eau et qui, introduit à l'état sec, ressort à l'état saturé, ayant entraîné une partie de l'humidité du fil.

Thus, according to the invention, there is proposed a method and a system for taking up wicks, by means of which it is possible:

• - to convey the material without pinching and therefore without risk of fouling of mechanical parts for driving the wick;
• - to give strong temporary cohesion to the wick;
• - give it a round shape, in particular by reducing the hairiness of the thread; the surface structure imparted is such that the thread acquires a relatively high final toughness and good compactness after drying;
• - to self-regulate the tension of the fibrous material, more surely than by mechanical traction;
• - Peeling the material out of the wet treatment device, gathering the marginal fibers well, which is a particularly critical point of the sizing installations;
• - to carry out a self-expression which can reach 80 to 100 Z in the case of a wet spinning installation, self-expression due to the twist and to the drying effect caused by the current of compressed air which pulverizes the water droplets and which, introduced in the dry state, leaves in the saturated state, having entrained part of the moisture of the wire.

Finally, the invention relates to an installation comprising a wet treatment station for fibrous material followed by the wicking recovery system.

Note that other systems interested in pneumatic torsion are also known, but these systems do not, like the invention, propose the exclusive use of a single pneumatic means for twisting and pulling a wet wick.

This is how the American patent n ° 3983722 only concerns the twist of the wick, but does not propose any pneumatic traction.

As for the British patent n ° 2 053 293 which does not moreover concern a system for taking up a wick downstream from a wet treatment station, it shows separate pneumatic means for effecting on the one hand the twisting of a wick, on the other hand its transport. The torsion is ensured by the rotating movement of air in a tube downstream of an air injection device. The wick is transported, for its part, by the permanent suction existing in a transport tube and created by a pneumatic suction device fitted to the machine using the wick. This suction does not exclude friction along the tube; it requires a bulky installation and it allows only low forward speeds while the invention targets speeds of several hundred meters per minute, which makes it possible, if necessary, to project the wick onto a mat. downstream.

• - la figure 1 est une vue schématique en élévation d'une installation conforme à l'invention ;
• - la figure 2 représente en perspective un détail du système de reprise ;
• - la figure 3 est une coupe du détail de la figure 2, parallèle au conduit de défilement et à l'arrivée d'air comprimé (de détail des gouttières n'est pas montré) ;
• - la figure 4 est une coupe du détail de la figure 2, perpendiculaire au conduit de défilement (le détail des gouttières n'est pas montré) ; et
• - la figure 5 est une vue de dessus de la partie aval de l'installation de la figure 1, montrant la réception en spires de la mèche sur le tapis transporteur.

Other advantages and characteristics of the invention will emerge from the description of a particular embodiment made with reference to the appended drawings, in which:

• - Figure 1 is a schematic elevational view of an installation according to the invention;
• - Figure 2 shows in perspective a detail of the recovery system;
• - Figure 3 is a sectional view of the detail in Figure 2, parallel to the scroll duct and the compressed air inlet (detail of the gutters is not shown);
• - Figure 4 is a section of the detail of Figure 2, perpendicular to the scroll duct (the detail of the gutters is not shown); and
• - Figure 5 is a top view of the downstream part of the installation of Figure 1, showing the reception in turns of the wick on the conveyor belt.

Figure 1 schematically shows an installation with the wicking take-up system 1 according to the invention, downstream of a wet treatment station 2. It is in fact a wire called wick since it has no twist: it is a stretched wick having the characteristics of title (or linear mass) of a wire.

This wet treatment station 2 can for example be a station for gluing the wick, ending at its downstream section by two expressing cylinders 3.

Upstream of the processing station 2 there may be a drawing bench 4.

Downstream of the recovery system is located a drying station 5 of the wick, which the wick to be dried crosses by means of a conveyor belt 6. At the exit of the drying station, a winder not depicted receives the dried wick.

The recovery system 1 comprises a block 7 pierced with a rectilinear scroll duct 8. The block 7 is of any external shape, for example parallelepiped, and can be made of a transparent plastic material.

In the passage duct 8 opens a compressed air inlet 9 (connected to a source not shown), the orientation of which is such as to impart a twist to the wick and to make it pass. For this, the inlet 9, located in a plane parallel to the conduit 8, opens tangentially with respect to said conduit 8 (Figure 4) and is inclined relative to the direction of the axis (arrows 10, fig.3) of the wick in the passage duct 8 at an angle a advantageously between 120 and 155 ° C, depending on the nature of the fiber, the fineness of the thread, the nature of the adhesive, taking into account the tension necessary for "tear off" the wire, and the inclination of the receiving mat in relation to the axis of the jet.

By way of example, a device has been successfully tested, the scrolling duct 8 of which, proportioned to the titer of the wick, has a diameter of 1.6 mm, into which emerges, at a distance 1 of 15 mm from the outlet 1-1 of block 7, an inlet 9 of 1 mm in diameter, preceded by an enlargement 12 of 5.7 mm in diameter, inclined relative to the direction of advance 10 by an angle a of 145 °. The compressed air consumption at around 1 bar was of the order of a few liters per minute.

In general, it can be assumed that the ratio of the length of the duct to its diameter is between 2 and 50, and preferably between 4 and 20, for diameter values between 0.5 and 6 mm depending on the yarns to be produced, and preferably between 1 to 3 mm. The ratio between the diameter of the conduit and that of the yarn is advantageously between 1.5 and 8 (taking into account, however, the imprecision on the diameter of the yarn in its state under low tension and relatively strong twist). The ratio of the diameter of the passage duct to that of the nozzle is advantageously between 1 and 5, and preferably between 1.4 and 3, with the search for the minimum flow rate sufficient to obtain the traction effect.

But it should be understood that none of these values is critical and that they can be modified as a function of the characteristics of the wick and of the desired effects (for example more or less large traction effect, depending on the inclination of the air intake relative to the direction of travel).

The wick 13 leaving the wet treatment station 2 is therefore twisted and simultaneously pulled under the wrapping effect of the helical air current produced by the inlet 9. Still under the effect of this helical air current, the wick 13 ', coming out of block 7, is expelled from it with a certain force. By having receiving means such as the conveyor belt 6 substantially on the path of the wick 13 ', the latter is projected there and remarkably forms non-regular turns 14 but generally fairly homogeneous in their dimensions. This projection, which is done without the assistance of mechanical organs allows a deposit without constraint, so that the yarn will be able to be released from all internal tensions (shrink freely) during drying.

The mat 6, made of a material of low adhesion, for example in a glass mesh "teflon"; leads the wick to a drying station 5. Drying gives the wick all its cohesion and then allows reeling to be done normally.

The case where the recovery system is downstream of a gluing head is particularly advantageous since it makes it possible to take up and convey the material without contact with mechanical members and therefore to avoid any risk of fouling of these members.

It should be noted that if contacts occur inside the passage conduit between the wick and the latter, these contacts then have a permanent character (these are frictions) which opposes drying and accumulation of glue on the walls of the duct.

It may however appear, after a certain time of use of the system according to the invention, deposits of material at the outlet and at the inlet of the scrolling duct 8. Also, a self-cleaning device is provided which can comprise two gutters 15 hollowed out on the upper part of the block 7 and joining an upper point of water supply 16 to the drip respectively at the inlet 17 and at the outlet 11 of the scroll duct 8. It can be provided , as shown, a single upper gutter 15 which distributes the water towards the inlet 17 and the outlet 11 of the scrolling duct, aided in this by two intermediate inlet and outlet gutters 19.

The shape and position of the gutters take account of the shape and position of the block 7, which is not necessarily horizontal as shown, but can be tilted, in a manner compatible however with the projection which must be carried out. In all cases the gutters are designed so as to distribute the water between the inlet and the outlet of the channel so as to maintain a concentration of material therein sufficiently low to prevent its deposition and to promote its entrainment with the wick.

Claims (9)

1. Method for taking up a wick of fibrous material having little or no cohesion downstream from a wet treatment station for said material, characterized by the exclusive use of a single pneumatic means (1) for twisting and pulling said wick of material (13), by which means is directed onto the wick at least one air jet oriented substantially tangentially relative to the wick and substantially inclined relative to the direction of advance thereof. 2. Method according to claim 1, characterized in that said torsion-traction means (1) of the wick (13,13 ') is used to project the latter onto a transfer device (6). 3. System for taking up a wick of fibrous material having little or no cohesion downstream from a wet treatment station for said material, characterized in that it comprises a single pneumatic means (1) for twisting and pulling said wick (13), being constituted by a passage duct (8) of the wick (13) into which a compressed air supply (9) opens tangentially with respect to said conduit (8) and substantially inclined with respect to the direction of advance (10) of it. 4. System according to claim 3, characterized in that said means comprises a self-cleaning device (15,16). 5. System according to claim 4, characterized in that the scrolling conduit (8) is pierced in a block (7) in the upper surface of which two gutters (15-18; 15-19) join a feed point in water (16) respectively at the inlet (18) and at the outlet (19) of the conduit (8). 6. Installation comprising a digital processing station (2) of fibrous material, characterized e in that it comprises, downstream of said station (2), the recovery system (1) according to any one of claims 3 to 5. 7. Installation according to claim 6, characterized in that it comprises, downstream of the recovery system (1), a carpet (6) leading to a drying station (5). 8. Installation according to any one of claims 6 or 7, characterized in that it is an installation for spinning wet flax without twisting. 9. Installation according to any one of claims 6 or 7, characterized in that it is a twist-free spinning installation by gluing wick.

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