EP0524111A1 - Apparatus for thermically treating moving yarns - Google Patents

Abstract

Apparatus for the treatment of moving yarns, for example during a drawing/texturing operation, of the type consisting of an insulating enclosure which surrounds a heating unit, with which it defines an outwardly open longitudinal channel, within which the yarn (5) to be treated passes, means for guiding said yarn (5) being provided in order to ensure its positioning within said channel. …<??>It is characterised in that the heating unit consists of an assembly comprising at least two cylindrical sections (A, B) having different diameters and arranged in the extension of one another, means (7, 8, 9, 10) for guiding the yarn (5) being provided over the length of said cylindrical units, so that said yarn (5) is maintained at a constant distance from the surface of the cylinder (A) of small diameter, in such a way that its rise in temperature is obtained in this zone by radiation and that it comes into contact with the surface of the zone (B) of large diameter, the transmission of heat then taking place by contact or conduction. …<IMAGE>…

Description

The present invention relates to an improvement made to the devices for the thermal treatment of moving wires, in order to confer on the latter certain shrinkage properties and / or bulkiness and / or elasticity.

In the following description, the conventional expression "oven" will be used to designate such a device which, of course, can be used both for treating continuous, single or multifilament yarns, as well as fiber yarns.

In all methods of treating moving wires requiring passage through an oven, the main problem that arises is that of rapid heat transmission, the heat having to penetrate regularly to the core and in the same way over the entire length of wire. As is well known, the temperature of the treatment and its regularity have a very great influence on the qualities of the wire produced.

It is well known that the heat treatment varies according to the material treated, the title of the wire and its speed of passage inside the oven. Thus, it is easy to see that we will reach the heart of a fine wire more quickly than that of an important track. Likewise, we know that we cannot process a wire above a certain ceiling temperature, otherwise we will degrade it. Consequently, this question of heat exchange being very important in the textile field, numerous solutions have been envisaged to resolve it, these solutions calling upon the three main principles of heat exchange, namely convection, radiation, conduction.

In addition to this problem of good heat transmission, there is also that of maintaining the wire under a determined tension, depending on the treatment which is carried out. Thus, for example, in the case of a drawing operation, possibly combined with a texturing operation, it is necessary that the wire is kept under a maximum tension whereas, on the other hand, when it is desired to carry out a retraction of the wire, the tension must be reduced.

Finally, there is also the problem of increasing production speeds on a textile machine, which went from a few tens of meters per minute about thirty years ago to a thousand meters, or even more currently, these high speeds being generators of phenomena, such as vibrations, difficult to control.

Among the solutions proposed to obtain very good regularity in the heat transmission and also to facilitate the problems of temperature regulation from position to position on a machine so that the entire production is homogeneous, it has been envisaged for a very long time to carry out heat treatments which could be described as "sequential" by making ovens along the length of which follow several distinct heat treatment zones. Among these solutions, mention may be made of those which are the subject of French patent 1 204 634, in which two successive treatments are carried out inside the same oven, one during which the wire is subjected to a temperature considerably higher than that of the normal temperature to which the wire must be brought, and this for a period such that the latter is not damaged, this first phase being followed by an equilibrium treatment at a conventional temperature. Such an attractive solution by the fact that it makes it possible to considerably reduce the length of the ovens for a given scrolling speed, however requires apparatuses of complex design, difficult to install. artwork.

A similar solution is described in French patent 1,216,847 and its certificate of addition 76861.

For other types of treatment, it may be desirable to have a different heat exchange sequence, for example to have a slow and regular rise in the temperature rise of the wire followed by a greater thermal shock, or to combine such phases differently.

Now we have found, and this is what is the subject of the present invention, a new type of oven of particularly simple design, which not only makes it possible to carry out such treatment combinations, but also allows speeds of passage of the wire inside the oven very high, the heat exchange being carried out very regularly, the risks of vibration (therefore of irregularity in the heat treatment) being practically completely eliminated, the placing of the wire inside such an oven is also facilitated with practically total elimination of the risks of deterioration of the wire during this very delicate operating phase to be carried out at high production speed.

Furthermore, the new type of oven according to the invention also makes it possible to solve an important problem which arises when synthetic threads are subjected to heat treatments at high temperature, namely that of the elimination of the solid deposit which occurs. in general at the top of the heating element and which results from the release of vapor which condenses at this level or above it in an area where the temperature begins to decrease.

To solve this problem, which has been demonstrated for decades, in particular during false twist texturing operations which have developed following the appearance of chemical fibers, numerous solutions have been proposed.

Among these solutions, mention may be made of that which is the subject of French patent no. 1,194,278 (corresponding to USP 2,994,319) and which consists in providing at the outlet of the oven a removable tip which can be easily replaced when dirty so that it can be cleaned outside the machine for new use.

Another solution, proposed at the same time (see in particular US Pat. No. 3,066,471), consists in carrying out a suction at the outlet of the oven, thus making it possible to eliminate the fumes produced during the treatment.

Finally, it has also been proposed, as is apparent in particular from French patent 1,363,920 (which corresponds to US patent 3,283,414), to carry out not only a suction of the fumes at the outlet end of the oven, but also a blowing air inside said oven in the direction of movement of the oven. This latter solution, commonly designated by the expression "suction / blowing" used in machines as described in US Patents 3,942,312 and 4,051,650, is the one which has finally imposed itself and is still used today.

Such a solution is however not suitable for ovens making it possible to process wires at very high speed (more than a thousand meters per minute), and for which the temperature inside the oven can be raised to several hundred degrees, or even reach more than 1000 ° C, which therefore implies particularly drastic treatment conditions.

However, the new type of oven according to the invention allows, as will be seen in the following description, according to one of its preferred embodiments, to produce assemblies making it possible to effectively eliminate the fumes produced during the treatment. avoiding any fouling of the oven during production.

In general, the new type of oven according to the invention for the thermal treatment of a wire, for example during a drawing / texturing operation, is of the type constituted by an insulating enclosure which surrounds a block heater, with which it defines a "channel" which can be opened to the outside, inside which passes the wire to be treated, means for guiding said wire being provided to ensure its positioning inside said channel, and it is characterized in that the heating block is constituted by an assembly comprising at least two cylindrical sections having different diameters, arranged in the extension of one another, means for guiding the wire being provided over the length of said blocks cylindrical so that the wire is kept at a constant distance from the surface of the small diameter cylinder (s), so that its temperature rise is obtained in this or these zones by radiation , and that it comes into contact with the surface (s) of large diameter, the heat transmission then being carried out by contact (or conduction).

Thanks to such a design, it is therefore possible to produce separate heating zones by radiation and conduction, zones which can be combined anyway along the length of the furnace.

• des moyens d'aspiration des fumées produites lors du traitement, sont avantageusement prévus à la sortie du four ; dans un tel cas, lesdits moyens d'aspiration sont, selon une forme préférentielle conforme à l'invention, constitués par un boitier qui entoure la sortie du four et qui est disposé à l'extérieur de l'enceinte, ledit boitier étant relié à une source d'aspiration et présentant une fente permettant un appel d'air depuis l'extérieur ;
• l'élément chauffant est avantageusement constitué d'un ensemble monobloc, réalisé en céramique ou acier inoxydable, la (ou les) zone(s) cylindrique(s) de faible diamètre supportant sur leur longueur des bagues munies d'éléments de guidage permettant de maintenir le fil à une distance constante de la surface chauffante, et la zone (ou les zones) de grand diamètre comportant également des bagues de guidage permettant de faire venir tangenter le fil avec la surface de cette partie cylindrique, le trajet du fil dans cette zone pouvant être soit rectiligne, soit de préférence légèrement en forme d'hélice (angle compris entre zéro et 180°) ;
• il peut être envisagé d'avoir une bague de sortie orientable permettant, lors du lancement, d'avoir l'ensemble des éléments de guidage alignés les uns par rapport aux autres, puis de faire pivoter le dernier élément de guidage pour obtenir l'embarrage souhaité dans la zone de contact ; une telle forme de réalisation permet éventuellement d'associer à l'élément de guidage mobile un volet qui peut prendre deux positions, l'une, lorsque ladite bague orientable ou mobile est alignée avec les autres bagues de guidage lors du lancement du fil, tel que le canal longitudinal soit bien ouvert sur l'extérieur puis, lorque ladite bague de sortie est déplacée, pour que le fil forme une hélice dans la zone de contact, que ledit volet vienne alors recouvrir le canal longitudinal ouvert sur l'extérieur, de telle sorte qu'en fonctionnement normal, on obtienne un conduit de traitement fermé permettant une meilleure homogénéité dans la zone de radiation, ainsi qu'une réduction des pertes calorifiques (puissance consommée) ;
• selon une variante selon laquelle le four conforme à l'invention est conçu pour pouvoir traiter simultanément deux fils, les bagues de guidage peuvent être fixes et présentent des gorges d'appui pour les fils positionnés de telle sorte à obtenir un positionnement immédiat et parfait du fil sur toute la longueur du four ;
• la mise en température des éléments chauffants proprement dits, est avantageusement obtenue par une résistance électrique noyée à l'intérieur du bloc, résistance comportant un thermocouple incorporé permettant une régulation parfaite de température ; l'élément chauffant peut être soit noyé et faire corps de manière permanente avec le bloc qui l'entoure, soit éventuellement être monté de manière amovible à l'intérieur de celui-ci ;
• les dimensions d'un tel four et les gammes de températures qu'il permet d'obtenir seront adaptées en fonction des traitements à réaliser ; à titre indicatif, pour une machine de texturation par fausse torsion, la longueur totale peut être comprise entre 0,3 et 2,5 mètres, les zones cylindriques de diamètre différent pouvant être soit de longueur égale soit de longueur différente.

Advantageously, in practice, in accordance with the invention:

• means for extracting the fumes produced during the treatment are advantageously provided at the outlet of the oven; in such a case, said suction means are, in a preferred form according to the invention, constituted by a box which surrounds the outlet of the oven and which is arranged outside the enclosure, said box being connected to a suction source and having a slit allowing a call for air from the outside;
• the heating element advantageously consists of a monobloc assembly, made of ceramic or stainless steel, the cylindrical zone (s) of small diameter supporting on their length rings provided with guide elements making it possible to maintain the wire at a constant distance from the heating surface, and the zone (or zones) of large diameter also comprising guide rings making it possible to bring the wire to tangent with the surface of this cylindrical part, the path of the wire in this zone which can be either rectilinear or preferably slightly helical in shape (angle between zero and 180 °);
• it can be envisaged to have an orientable outlet ring allowing, during launching, to have all of the guide elements aligned with respect to each other, then to pivot the last guide element to obtain the interlocking desired in the contact area; such an embodiment optionally makes it possible to associate with the movable guide element a flap which can take two positions, one, when said orientable or movable ring is aligned with the other guide rings during the launching of the wire, such that the longitudinal channel is well open on the outside then, when said outlet ring is moved, so that the wire forms a helix in the contact area, that said flap then comes to cover the longitudinal channel open on the outside, so that in normal operation, a closed treatment duct is obtained allowing better homogeneity in the radiation zone, as well as a reduction in losses heat (power consumed);
• according to a variant according to which the oven according to the invention is designed to be able to treat two wires simultaneously, the guide rings can be fixed and have support grooves for the wires positioned so as to obtain an immediate and perfect positioning of the wire along the entire length of the oven;
• the heating elements themselves are brought to a temperature, advantageously obtained by an electrical resistance embedded inside the block, resistance comprising an incorporated thermocouple allowing perfect temperature regulation; the heating element can either be embedded and form a body permanently with the block which surrounds it, or optionally be removably mounted inside thereof;
• the dimensions of such an oven and the temperature ranges which it makes it possible to obtain will be adapted according to the treatments to be carried out; As an indication, for a false twist texturing machine, the total length can be between 0.3 and 2.5 meters, the cylindrical zones of different diameter being either of equal length or of different length.

• les figures 1 et 2 illustrent schématiquement, respectivement en perspective et en élévation, la structure d'un élément chauffant d'un four réalisé conformément à l'invention ;
• les figures 3 et 4 illustrent, de manière schématique et en perspective, un four réalisé conformément à l'invention et qui comporte une bague de sortie mobile, permettant de faire former au fil une hélice dans la zone de contact et également d'obturer le canal longitudinal ouvert de passage du fil en fonctionnement normal ;
• les figures 5 et 6 illustrent, de manière schématique, une variante préférentielle d'un four conforme à l'invention, comportant un ensemble d'aspiration permettant d'éliminer les fumées produites lors du traitement du fil, la figure 5 étant une vue en coupe longitudinale et la figure 6 une vue partielle, en perspective, montrant la structure de l'ensemble d'aspiration d'un tel four permettant de traiter simultanément deux fils en parallèles ;
• la figure 7 est une vue en perspective éclatée d'un mode préférentiel de four conforme à l'invention équipé d'un ensemble d'aspiration des fumées et ;
• la figure 8 est une vue en élévation d'une position de travail d'une machine de texturation par fausse torsion équipée d'un four conforme à l'invention.

The invention and the advantages which it brings will however be better understood thanks to the exemplary embodiments given below for information but not limitation, and which are illustrated by the appended diagrams in which:

• Figures 1 and 2 schematically illustrate, respectively in perspective and in elevation, the structure of a heating element of an oven produced in accordance with the invention;
• Figures 3 and 4 illustrate, schematically and in perspective, an oven produced according to the invention and which comprises a movable outlet ring, making it possible to form a wire in a helix in the contact area and also to close the open longitudinal channel for passage of the wire in normal operation;
• Figures 5 and 6 schematically illustrate a preferred variant of an oven according to the invention, comprising a suction assembly for eliminating the fumes produced during the processing of the wire, Figure 5 being a view in longitudinal section and Figure 6 a partial perspective view showing the structure of the suction assembly of such an oven for simultaneously treating two son in parallel;
• Figure 7 is an exploded perspective view of a preferred mode of oven according to the invention equipped with a smoke extraction assembly and;
• Figure 8 is an elevational view of a working position of a false twist texturing machine equipped with an oven according to the invention.

Figures 1 and 2 illustrate the heating element of an oven produced in accordance with the invention, the means for guiding the wire inside said oven, the structure of the insulating enclosure, the means for bringing the temperature up to the heating and regulating element not being shown for simplification.

If one refers to these Figures 1 and 2, the heating element of the oven according to the invention consists essentially of a block of generally cylindrical shape comprising two zones A and B of different diameters. In the example illustrated, the zones A and B have identical lengths, but possibly can have different lengths. Furthermore, the difference in diameters of the two zones will generally be of the order of a few millimeters. As an indication, for a machine, texturing oven, a difference in diameter D - d of the order of eight to ten millimeters, is suitable for most textile materials. Such a block is preferably made in one piece, for example by molding and / or machining of a ceramic or a stainless steel. In the case of a heating element based on stainless steel, the large diameter zone will preferably be treated superficially so as to increase its hardness, for example treatment with plasma, chromium, etc. Inside the block thus produced, is embedded a heating resistor preferably comprising an incorporated thermocouple element, allowing to achieve precise temperature regulation. Only the connection elements of these heating elements have been shown in FIG. 1.

According to the invention, on the block thus produced, there are mounted guide elements (1,2,3,4) making it possible, on the one hand, to keep the wire (5) away from the heating surface of zone A, which makes it possible to obtain in this zone a heating by radiation, and on the other hand, to maintain said wire (5) in contact with the surface of the cylinder in zone B, thus making it possible to obtain a heating by contact or conduction .

Such guide elements are constituted, in the embodiment illustrated in Figures 1 to 4, by stainless steel rings (1,2,3,4), four in number in this case, and which include elements guide (7,8,9,10) defining a slot open towards the outside; the guide elements (7,8,9,10) are constituted for example by ceramic or tital eyelets, V-shaped or U-shaped, attached to the inside of the rings (7,8,9,10). These guide eyelets define with the insulating enclosure not shown a longitudinal "channel", open to the outside, inside which passes the wire to be treated.

The first three guide rings (1,2,3) are arranged so that the wire (5) follows a straight path in zone A, while the ring (4) called "output ring" is, is aligned on the contrary, with the above-mentioned rings, it is slightly offset in order to achieve, as can be seen from FIGS. 1 and 2, a fastening of the wire (5) around the surface of zone B.

To facilitate the implementation and improve the treatment conditions, the outlet ring (4) can be mounted in an adjustable and mobile manner in particular to facilitate the launching operation, the ring (4) then being aligned with the rings (1 , 2,3) then, slightly offset to embarrass the wire (5) around the surface of zone B. Such an embodiment is illustrated in FIGS. 3 and 4. In this embodiment, the heating element proper is surrounded by an insulating block (15) of refractory material, and which has an open slot (16) outwards. The carcass surrounding this block has not been shown for simplification purposes. During launch, the four guide rings (1,2,3,4) are aligned as shown in FIG. 3. The outlet ring (4) is associated with a shutter flap (13) in the form of a sheath, for example made of a stainless steel strip which is arranged between the insulating block (15) and the actual heating element. This shutter flap (13) has a longitudinal slot (14). Thanks to such a design, during launching (FIG. 3), the slot (14) is in accordance with the slot (16) of the insulating block, which makes it possible to put the wire in place and, this being done, for production normal (Figure 4), it suffices to maneuver the outlet ring so as to rotate it to bring it into the position shown in this figure 4. When the outlet ring (4) is rotated, the sleeve (13 ) (or flap) then covers the openings of the guide eyelets, which allows to form, in normal operation, a closed conduit inside which passes the wire (5) to be treated.

Figures 5 and 6 illustrate an oven according to the invention equipped with a smoke suction system, disposed at the outlet of the oven.

If we refer to these figures and using the same references as those used for FIGS. 2 to 4, such an oven is composed as before of an insulating enclosure (15) which surrounds a heating block of generally cylindrical shape, and which has two zones A, B of different diameters, thus making it possible to have in zone A a heating by radiation and in zone B a heating by contact. As before, rings (1,2,3,4) comprising guide elements (7,8,9,10) are associated with the heating element to ensure the positioning of the wire (5) inside the oven .

At the outlet of said oven, is arranged an assembly designated by the general reference (20), in the form of a housing and which is connected by means of a conduit (21) to a suction source not shown. This box has, over part of its height, a slot (22) arranged in alignment with the slot (16) that comprises the insulating block (15), and which allows the wire to be put in place during the operation launch. The upper part of this slot (22) is, in turn, positioned so that it is in agreement with the guide eye (10) for the exit of the wire. It is thus possible, as shown in FIG. 6, to perfectly position two wires (5) in parallel inside the oven. Such a particularly simple design assembly makes it possible to completely eliminate the fumes and condensates leaving the oven, and this without altering the actual processing conditions.

Figure 7 illustrates in perspective, exploded, an oven comparable to that illustrated in Figures 5 and 6, and which differs from the latter by the fact that it comprises a shutter flap (23) pivoting and that the guide rings are simply three in number (rings 1,3,4), the intermediate ring (2) provided on the zone A of small diameter being eliminated. The grooves for ensuring the positioning of the wires (5) provided on the guide rings, are offset with respect to each other, so that the two wires (5) are well maintained at a constant distance in the zone A of the heating surface, and in contact with the surface of the heating element in zone B.

Such an oven design is particularly suitable for making texturing machines, in particular by false twist, compact, as illustrated in FIG. 5. In such a machine, the oven according to the invention designated by the general reference F, is arranged between a feeder (10) for the wire (5) and a cooling zone (11) followed by a false twist pin (12). The oven F is, in such a case, designed so that in the entry zone A, the wire is heated by radiation, while in the exit zone B, it is heated by conduction. Compared to previous solutions, it is possible to reduce the length of the oven for a determined processing speed, since in zone A, the wire is not in contact with the surface of the heating element, it can be high temperature very quickly, zone B making it possible to promote heat exchange, also ensuring the guiding and positioning of the wire in the zone of conduction heating. Such a design also avoids, especially when working at very high speed (1000 or 2000 m / min), the harmful phenomena of wire vibration (5).

Other embodiments can also be envisaged, such as for example making the oven from a single block comprising two different zones constituted for example by two cylindrical channels having different diameters, arranged in the extension one of the other, the wire being in contact with the surface of the channel of small diameter, and being kept apart from the surface of the other channel of larger diameter, which thus makes it possible to carry out the two types of heating, radiation and contact (or conduction) according to the invention. It may also be envisaged to juxtapose, one after the other, elementary modules, each module making it possible to produce a type of heating.

As an indication, such an oven can have a length between 0.3 and 2.5 meters, a temperature between 100 ° C and 1500 ° C, temperature of course depending on the speed of passage of the wire and the treatment.

Of course, the invention is not limited to the embodiment described above, but it covers all the variants produced in the same spirit.

Claims (11)

1 / Device for treating moving wires, for example during a drawing / texturing operation, of the type constituted by an insulating enclosure which surrounds a heating block with which it defines a longitudinal channel open to the outside, inside which passes the wire (5) to be treated, means for guiding said wire (5) being provided to ensure its positioning inside said channel, characterized in that the heating block consists of an assembly comprising at least two cylindrical sections (A, B) having different diameters, arranged in the extension of one another, means (7,8,9,10) for guiding the wire (5) being provided along the length of said blocks cylindrical, so that said wire (5) is kept at a constant distance from the surface of the cylinder (A) of small diameter, so that its rise in temperature is obtained in this area by radiation, and that it comes into contact with the area of the area (B) of large diameter, the heat transmission then being carried out by contact or conduction. 2 / Device according to claim 1, characterized in that the path of the wire in the contact area (B) is rectilinear. 3 / Device according to claim 1, characterized in that the path of the wire in the contact area is in the form of a helix (angle between zero and 180 °). 4 / Device according to one of claims 1 to 3, characterized in that it comprises means for extracting the fumes produced during the treatment, arranged at the outlet of the oven. 5 / Device according to claim 4, characterized in that the suction means are constituted by a housing (20) surrounding the outlet of the oven, arranged outside the enclosure (15), said housing being connected to a suction source having a slot (22) allowing a call for air from the outside. 6 / Device according to claim 5, characterized in that said slot (22) allows an introduction of the wire (5) inside the oven during the launching operation by lateral movement, and also serves as a guide element for the wire coming out of the oven. 7 / Device according to claim 6, characterized in that the path is designed to be able to simultaneously treat two wires (5), the slot (22) having, seen from the front, a T-shape, the two wires being positioned in normal operation at the end of the branches of said T. 8 / Device according to one of claims 1 to 7, characterized in that the heating element is formed from a one-piece assembly, ceramic or stainless steel, the cylindrical zone of small diameter (A) supporting over its length rings (1,2,3) provided with guide elements making it possible to maintain the wire (5) at a constant distance from the heating surface, the large diameter zone (B) comprising at its inlet and at its outlet also two guide rings (3,4) allowing the wire to come into tangency with the surface of this cylindrical part. 9 / Device according to claim 8, characterized in that the ring (4) outlet is orientable and allows, during launching, to have all of the guide elements (1,2,3,4) aligned with each other relative to the others, then rotate the last guide element (4) to obtain the desired locking in the contact zone (B). 10 / Device according to claim 9, characterized in that the outlet ring (4) is associated with a flap or sheath (13) for closing the longitudinal channel open to the outside, so as to form a closed conduit to inside which the wire (5) passes in normal operation. 11 / Device according to one of claims 1 to 10, characterized in that the heating of the actual heating elements is obtained by an electrical resistance embedded inside the block, resistance comprising a thermocouple incorporated allowing perfect regulation of the temperature, this heating element being either embedded and integral with the block which surrounds it, or optionally removably mounted inside of it.

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