EP1638708B1 - Method for managing a continuous in-line metal strip processing installation, and installation for implementing this method - Google Patents

Description

The subject of the invention is a method for managing the input of a new reel in a continuous online processing facility of a web product and also covers an improved processing facility for implementing the method (see FIG. for example US-A-2,662,271 ).

It is known that the process of manufacturing steel products, in particular metal strips, requires a series of successive treatments. In general, after the elaboration of the steel and its casting in molds or by continuous casting, a hot rolling is first carried out and the product wound in a reel is then subjected to various operations, generally an annealing, stripping to remove scale and a cold rolling that can be carried out either on a reversible train or on a tandem mill. The strip thus laminated can then be subjected to various treatments, for example degreasing, tempering, pickling, surface coating, etc.

The evolution of the technique leads more and more to consolidate in a continuous line some treatments that previously were performed in separate equipment, the tape being wound into a reel at the end of a treatment to be transported in the equipment next to undergo another treatment.

The tape to be processed, fed in the form of coils placed one after the other on a reel, passes successively in the various sections of the installation. To carry out the continuous treatment, it is therefore necessary, at the end of unwinding of a coil, to fix the tail thereof, that is to say its downstream end in the direction of travel, on the head of the coil. next coil, that is to say the upstream end in the direction of scrolling. This junction, which must be able to withstand the forces applied to the strip during the scrolling in successive sections of the installation is performed, most often, by electrical welding, particularly in the case of steel strips.

For example, it is possible to apply the two parts to be welded to each other, but this results in an excess thickness, and generally, it is preferred to perform edge-to-edge welding by flashing.

In all cases, it is necessary that the two ends, respectively downstream and upstream of the two successive bands to be welded, are perfectly parallel and they are thus sheared before welding by means that can be integrated into the welding equipment.

However, since reels from the hot rolling mill are processed, a trimming operation must first be performed in order to eliminate the head and the tail of the reel which are not rectilinear and may have some defaults.

The process of connecting two consecutive bands thus comprises, on the one hand, operations for preparing the ends of the two bands and, on the other hand, the actual joining operations. The set of operations is carried out in successive stages in equipment which, generally, are grouped in an input section of the associated installation, most often with two unwinders respectively carrying, one the coil at the end of unwinding and the other the new coil to be processed.

At the end of the unwinding of the first coil, it is therefore necessary, first of all, to trim the tail of the latter in an input shear and then position the band in the welding machine and proceed to shear from its downstream end. During this time, it was possible to begin the unwinding of the first reel, starting from the second reel and to trim the head of the reel by means of an input shear. The new band is then introduced into the welding machine, positioned and sheared.

Advantageously, the ends of the two strips are sheared at the same time in the welding machine which, for this purpose, is associated with means for positioning and clamping the ends of the two strips to be welded and for shearing means of the two ends along two perfectly parallel lines which are then brought closer together to perform the welding, in particular by flashing, by passing an electric current between the two strips to be welded.

• tout d'abord, un cycle de préparation comportant l'éboutage de la queue de la première bande et son positionnement dans la soudeuse, puis l'introduction de la bande suivante avec éboutage de sa tête et son positionnement dans la soudeuse.

The equipment placed in the entrance section of the installation therefore performs a series of operations that can be divided into two successive cycles:

• firstly, a preparation cycle comprising the trimming of the tail of the first band and its positioning in the welder, then the introduction of the next band with trimmer head and positioning in the welder.

Then, the actual junction cycle comprising shearing the ends of the two strips to form two parallel edges facing, their bringing together and welding and the finishing of the weld.

All these operations require, obviously, a certain time during which the scrolling of the band must be stopped or, at least, slowed down to a minimum speed.

Indeed, if we can perform trimming and shearing strips by parade, by means of a flying shear, the positioning of the two ends to be welded and the welding operation normally require a complete stop.

However, in most continuous line processing facilities, the tape must be run continuously.

For this purpose, it was proposed in the document US 2,662,671 (Greenberger ), to have two pits respectively upstream and downstream of the welder, in which can accumulate a certain length of strip, in superimposed turns, the upstream pit can be covered with a transversely displaceable platform, and on which is placed a conveyor.

During the course of a first coil, the band passes over the upstream pit which is covered with the platform. On the other hand, a certain length of band is accumulated in the downstream pit. The scrolling process is stopped when the tail of this first coil reaches the level of the welder.

We then begin the unwinding of a second coil whose head passes on the platform, above the upstream pit, then comes to be placed in the welder to be secured to the tail of the first coil whose scrolling could be continued, meanwhile, thanks to the length of band accumulated in the downstream pit.

The platform is then discarded and a certain length of the second band can accumulate in the upstream pit.

At the end of the unwinding of the second band, the tail of the latter is held by pinch rollers in order to pass in the downstream pit, the accumulated length in the upstream pit. This can then be covered by the platform for the passage of the head of a third band which is placed in the welder for its junction with the tail of the second band whose scrolling can be continued through the accumulated length in the downstream pit.

Such an arrangement therefore allows continuous operation but the accumulation of the band in each pass, in superimposed turns, may deteriorate the surface quality.

Commonly used installations are also known for the continuous stripping of steel strips. In general, such a line comprises successively an annealing furnace and a stripping plant for the removal of scale, which is constituted, in most cases, of a series of tanks filled with acid in which the bandaged. Of course, other equipment may be necessary, for example a blasting descaling device placed before the pickling tanks to promote chemical pickling.

The normal speed of travel of the strip in acid trays is generally very high and can range, for example, up to 400 m / min. However, as we have just seen, the running of the strip must be stopped periodically, in the input section, to allow the operations of joining the tail of a coil with the head of the next coil.

Since the intensity of the etching depends on the residence time of the strip in the acid, it is necessary that the speed of travel in the tanks is substantially constant. That's why we interposed between the input section and the treatment section, for example stripping, an accumulation device which is filled in advance with a strip length stored in order to continue scrolling in the processing section at normal speed during the downtime in the input section for the joining of the two successive bands.

Likewise, the installation terminates in an output section comprising at least one winder of the reel strip. The wound length is obviously limited, it is necessary, at the end of the winding of a coil, cut the end thereof and engage the continuation of the band on another winder to allow the evacuation of the coil wound. These operations require a certain time to stop scrolling, during which stripping must continue.

Therefore, a downstream accumulator must be placed between the processing section and the output section in order to reserve the length of tape processed at normal speed during the evacuation time of a coiled coil.

In general, a continuous in-line treatment plant, in particular for stripping steel strips, successively comprises, in the running direction of the strip, an inlet section, an upstream accumulator, a section of processing, a downstream accumulator and an output section, the upstream accumulators and the downstream accumulator each having an accumulation capacity corresponding at least to the length of strip scrolling, at normal speed, in the processing section, respectively during the time stopping in the input section for connecting the head of a new spool to the tail of the previous spool and during the stopping time in the outlet section for the evacuation of the wound spool.

As indicated above, the connection between two consecutive bands requires a series of operations performed by the different equipment of the input section.

• A: Arrêt dans la section d'entrée de la bobine en fin de déroulement. La vitesse de défilement étant élevée, par exemple 400 m/mn, le temps d'arrêt peut être de l'ordre de 5 secondes comme indiqué sur le diagramme.
• B : Coupe pour l'éboutage de la queue de la bande en fin de déroulement.
• C : Positionnement dans la soudeuse de la queue de la première bande.
• D : Introduction de la bande suivante à partir de la seconde dérouleuse. Cette opération nécessite l'engagement de la tête de la bobine suivante dans les équipements d'entrée et peut donc demander un certain temps, par exemple 10 secondes, comme indiqué sur le diagramme. Bien entendu, la tête de la bobine suivante doit être éboutée, mais cette opération a pu être réalisée à l'avance, chaque dérouleuse pouvant être associée à une cisaille d'entrée.
• E : Positionnement de la bande suivante dans la soudeuse, par exemple au moyen de guides latéraux d'entrée.

For example, the figure 1 is a diagram indicating, on the abscissa, the times required for the successive steps of the general process of connection between the tail of a coil at the end of unwinding and the head of a new coil, these steps, referenced A to K, being, for example, the following:

• A: Stop in the input section of the coil at the end of unwinding. The scrolling speed being high, for example 400 m / min, the stopping time can be of the order of 5 seconds as shown in the diagram.
• B: Cut for the trimming of the tail of the band at the end of unwinding.
• C: Positioning in the welder of the tail of the first band.
• D: Introduction of the next strip from the second unwinder. This operation requires the engagement of the next coil head in the input devices and may therefore require a certain time, for example 10 seconds, as shown in the diagram. Of course, the head of the next coil must be trimmed, but this operation could be performed in advance, each unwinder can be associated with an input shear.
• E: Position the next strip in the welder, for example by means of lateral inlet guides.

• F : Cisaillage des extrémités en vis-à-vis des deux bandes. Comme on l'a indiqué, les bords en vis-à-vis des deux bandes successives doivent être rectilignes et parfaitement parallèles, en particulier pour un soudage par étincelage. A cet effet, il est habituel d'utiliser une cisaille double permettant de réaliser en même temps, de part et d'autre de l'appareil de soudure, le cisaillage des deux bords en vis-à-vis. Cette opération peut donc être rapide et demander, par exemple, 5 secondes.
• G : Soudage des deux bords en vis-à-vis. Cette opération dépend du procédé de soudage mais peut demander, en moyenne 15 secondes.
• H : Finissage de la soudure, en particulier, lorsque l'on doit éviter une surépaisseur. Il est intéressant, en effet, de réaliser le soudage par étincelage mais l'on sait qu'il se produit alors un bourrelet qui risque de détériorer les cylindres de laminage. Ce bourrelet doit donc être éliminé par rabotage. Selon les cas, cette opération peut être effectuée soit dans la machine de soudage elle-même, soit légèrement en aval de celle-ci et, dans ce cas, il faut déplacer la jonction soudée depuis la machine de soudage jusqu'à la machine de rabotage.

It can be seen in the diagram that operations C, D, E can each require about 10 seconds.

• F: Shear ends facing the two bands. As has been indicated, the edges facing the two successive strips must be straight and perfectly parallel, in particular for flash welding. For this purpose, it is usual to use a double shear making it possible to perform at the same time, on both sides of the welding apparatus, the shearing of the two edges facing each other. This operation can be fast and ask, for example, 5 seconds.
• G: Welding of two edges vis-à-vis. This operation depends on the welding process but can require, on average 15 seconds.
• H: Finishing of the weld, in particular, when it is necessary to avoid an extra thickness. It is interesting, indeed, to perform the welding by spark but we know that it occurs then a bead which may deteriorate the rolling rolls. This bead must be removed by planing. Depending on the case, this operation can be carried out either in the welding machine itself or slightly downstream thereof and, in this case, it is necessary to move the welded junction from the welding machine to the machine of welding. planing.

• - I : Retour à la vitesse normale de défilement. Cette vitesse étant élevée, il faut un certain temps d'accélération qui peut être évalué à 5 secondes.

The time required for finishing operations can be of the order of 10 seconds.

• - I: Return to normal scrolling speed. This speed being high, it takes a certain acceleration time which can be evaluated at 5 seconds.

The diagram of the figure 1 shows that the dead time from the moment when one begins to reduce the speed until the moment when this one returns to the normal speed, exceeds 1 minute.

In addition, certain additional operations may be necessary in certain cases, for example, after welding, a notching step J of the ends of the welded part, which may take 10 seconds and a solder annealing step K which may require 40 seconds. These two steps can be performed at the same time before the acceleration of the band for the return to normal speed.

According to the diagram of the figure 1 , the overall time during which the scrolling must be stopped in the input section, can thus go from 75 to 115 seconds.

However, it appears that it is possible to distinguish, in this diagram, two successive cycles of operations which are carried out by different equipment, first of all a first preparation cycle P comprising the stopping of the scroll, the trimming of the ends of the two strips and their positioning in the welding machine and which therefore corresponds to the steps A to E and, secondly, a second cycle S junction itself, including the shearing of the two edges facing the two strips, their welding , the finishing of the weld and the return to normal speed and which therefore corresponds to operations F to I with, possibly, steps J and K.

Of course, the diagram of the figure 1 is only an example and other operations could possibly be added to the joining process, but in all cases, the dead time of stopping the scrolling for the joining of the two strips remains between 1 minute and 1 minute 30 .

However, as we have seen, the normal speed of scrolling is quite high, for example of the order of 400 m / min, and should, as far as possible, remain substantially constant. The upstream accumulator must therefore have a capacitance of between 400 and 600 meters so that the bandwidth stored supplies the treatment section during the downtime in the input section.

Such accumulators are extremely bulky and expensive but their use remains, however, profitable for important productions.

Therefore, in recent years, many facilities operating in a continuous line have been realized, not only for pickling but for other operations, for example cold rolling or surface coating.

However, for some time, customer needs have evolved and require, periodically, a modification of the load plan of a plant, the composition of the steel and the dimensions of the bands produced may vary quite often.

As we have just seen, a continuous on-line processing facility is provided in its input section with means for making the connection between successive coils without stopping the scrolling in the processing section. It is therefore possible to successively treat strips having different structural and dimensional characteristics, by welding them one after the other. However, the length of strip to be treated may also vary according to the needs and, in practice, quite often it is necessary to treat coils having a short length, for example from 300 to 400 meters. However, the upstream accumulator placed between the inlet section and the treatment section must feed the treatment section during a dead time of stopping in the input section whose duration can not be decreased below a certain limit because it results from a succession of functions whose elementary times are chained in sequences.

However, after emptying to feed the processing section during the downtime, the accumulator must be refilled again to allow connection with the next coil and, for this, the new tape is inlet section, at a speed higher than the normal processing speed, for example 600 to 800 m / min.

If the new coil is very short, its tail can arrive in the input section before the accumulator is completely filled and it is necessary, at this moment, to stop the scrolling in the input section again to make the junction by feeding the treatment section from the accumulator. If it is possible to absorb the passage of a single short coil, on the other hand, the insufficiency of filling can accumulate if several short coils must be treated successively.

The layout of the document US 2,662,671 would not solve this problem of short coils which, incidentally, did not arise at that time.

On the other hand, the present invention makes it possible to solve this problem by means of a new process and an improved installation which makes it possible to considerably reduce the dead time of the inlet section and, thus, to incorporate much more easily in the line of the coils of different sizes. In addition, thanks to this reduction of the input dead time, the invention makes it possible to increase the real processing speed and thus the productivity of the line.

The subject of the invention is therefore, in general, a method for managing the input of a new reel in a continuous online processing installation of a reel-wound web product, comprising a section of input fed in successive coils and in which the tail of a coil at the end of unwinding is connected to the head of a following coil for the formation of a continuously moving band, an upstream accumulator, a processing section, an accumulator downstream and an output section, the connection of two consecutive bands being made in the input section of the installation in two cycles of successive steps, respectively a first preparation cycle of the ends, respectively tail and head of the two bands for their joining and a second joining cycle of two edges facing said ends, comprising the approximation of said edges, their joining in a welding machine and finishing operations,
a method in which the running of the web is stopped or at least slowed down in the input section for a time necessary for all the connection operations and the processing section is fed during the downtime or slowing down, by a tape length stored in advance in the upstream accumulator, for further processing at a normal scrolling speed.

In a first embodiment of the invention, the second edge joining cycle with respect to the ends of the two strips is carried out in at least two parts of the inlet section, between which is interposed an intermediate accumulator for the setting aside a variable length of strip, respectively a first part in which the welding machine is placed, in order to perform a first phase of the joining cycle comprising the junction of the edges facing the two consecutive strips, and a second part in which is performed a second phase of the junction cycle comprising at least one finishing operation, the time required for all the connection operations of the two bands being thus divided into at least two periods, respectively a first period corresponding to the first cycle of preparation and a first phase of the junction cycle, and a second period corresponding to a seco nde phase of the junction cycle, said two periods being separated by a time interval of variable duration corresponding to the scroll in the intermediate accumulator of the stored length, the welding operation is carried out at the end of the first period in the first phase of the junction cycle, is passed through the intermediate battery the tail of the first band and its welded junction with the head of the next band, and it stops again scrolling in the second part of the entry section for performing at least one finishing operation during the second period corresponding to the second phase of the joining cycle.

In a second embodiment, the second edge joining cycle with respect to the ends of the two strips is carried out in at least two parts of the inlet section, between which is interposed an intermediate accumulator for the storage of a variable length of strip, respectively a first part in which the scrolling is stopped to achieve a first phase of the joining cycle comprising a temporary junction of the edges vis-à-vis the two consecutive strips, and a second part comprising the machine welding and in which is performed the final junction of the two strips and at least one finishing operation, the time required for all the connection operations of the two strips being thus divided into at least two periods, respectively a first period corresponding to the first cycle of preparation and a first phase of the junction cycle and a second period corresponded nt at a second phase of the junction cycle, said two periods, being separated by a time interval of variable duration corresponding to the movement, in the intermediate accumulator, of the stored length, the temporary junction of the tail of the first band with the head of the next band, at the end of the first period of the general connection process, then resumes the band travel to bring said temporary junction in the second part of the input section through the intermediate accumulator, and it stops again scrolling the band during the second period of the general connection process to perform the actual welding operation and at least one finishing operation in a second phase of the cycle of junction.

An essential idea of the invention therefore lies in the splitting of the junction cycle into two separate phases, with setting aside a variable length of band in an intermediate accumulator.

Particularly advantageously, before the end of the unwinding of the first coil, there are stored in the upstream accumulator and in the intermediate accumulator band lengths corresponding to their maximum capacity.

The method according to the invention thus makes it possible, during the first period of the joining process, to feed the normal-speed processing section from the upstream accumulator, and at the same time to pass through the upstream accumulator, from the intermediate accumulator, a length of tape capable of replacing at least a portion of the length passing through the processing section.

In addition, during the second period of the joining process, it is possible to feed the processing section at normal speed from the upstream accumulator and, at the same time, to control the scrolling in the first part of the section d. input, the length of band necessary for the recovery of the intermediate accumulator to its maximum capacity.

The invention also covers an improved installation for the implementation of the method, comprising, as usual, an input section, an upstream accumulator, a processing section a downstream accumulator and an output section.

• au moins deux dérouleuses fonctionnant alternativement, l'une pour le déroulement d'une bobine en cours de traitement et l'autre pour le déroulement de la bobine suivante, chaque dérouleuse étant associée à une cisaille d'éboutage
• un dispositif formant aiguillage pour l'engagement dans l'installation de la bande venant de l'une ou l'autre des deux dérouleuses,
• des moyens de positionnement, par exemple des guides latéraux d'entrée de bande dans la soudeuse,
• une machine de soudage associée à deux cisailles ou à une cisaille double pour le cisaillage de deux bords en vis à vis sur les extrémités des deux bandes,
• un équipement de finition, par exemple une machine de rabotage qui peut, éventuellement, être intégrée dans la machine de soudage,
• des moyens de positionnement tels que des guides latéraux pour la sortie de la bande et par exemple son entrée dans un tensionneur précédant l'accumulateur amont placé à l'entrée de la section de décapage.

As indicated, the process of connecting the tail of a reel at the end of unwinding with the head of a new reel is carried out in successive stages in different equipment which, sometimes, are grouped in the same machine but can also be separated. For example, to carry out the steps A to K described above, the installation comprises:

• at least two unrollers operating alternately, one for the unwinding of a reel being processed and the other for the unwinding of the next reel, each unwinder being associated with a shearing shear
• a switching device for the engagement in the installation of the strip coming from one or the other of the two unwinding machines,
• positioning means, for example lateral band entry guides in the welder,
• a welding machine associated with two shears or a double shear for shearing two edges facing each other on the ends of the two strips,
• finishing equipment, for example a planing machine which may possibly be integrated into the welding machine,
• positioning means such as lateral guides for the exit of the strip and for example its entry into a tensioner preceding the upstream accumulator placed at the inlet of the stripping section.

The invention is based on the idea that it was possible to divide the equipment of the input section into two physically separate parts by an intermediate accumulator, so that the whole connection process is divided into two separate periods. by a time interval of variable duration.

This intermediate accumulator will have a capacity corresponding at least to the running tape length in the normal speed processing section for the duration of the first period of the connection process.

As indicated above, during the second period of the connection process, this intermediate accumulator can supply the upstream accumulator so as to maintain it as far as possible at its maximum capacity. In this way, it is possible to give the upstream accumulator a capacity simply corresponding to the length of tape running in the processing section at normal speed during the second period of the connection process.

The invention makes it possible, in particular, to solve the problem of relatively short coils. Indeed, it is possible to manage the rate of filling the intermediate accumulator according to the length of each new coil so as to restore the upstream accumulator to its maximum capacity after each period of the connection process.

In particular, according to a preferred feature of the invention, it is possible to introduce a third coil into the input section as soon as the intermediate accumulator is sufficiently filled to allow a stop of the scrolling in the first part of the section. input, in order to join, at least temporarily, the tail of the new coil to the head of the third coil.

Thus, in a preferred embodiment of the invention, from the termination of the junction in the second part of the input section, the unwinding speed of the new coil is increased for filling, at least partially of the intermediate accumulator, so that, depending on the length of the new coil, the tail of the latter can be stopped in the first part of the input section for its junction with the head of a third coil, after setting aside a band length corresponding to at least the first period of the connection process.

By thus dividing into at least two periods separated by an interval, the overall time required for the connection of two successive coils, it is possible, thanks to the invention, to reduce the dead time for stopping the unwinding of the coils in the section of the coils. input, this dead time may, in practice, not exceed the longer of the two periods of the connection process.

• La figure 1 est un diagramme indiquant, à titre d'exemple, la durée des différentes étapes du processus général de raccordement de deux bandes successives.
• La figure 2 représente schématiquement la section d'entrée d'une installation, dans un premier mode de réalisation de l'invention.
• La figure 3 est un diagramme représentant le déroulement, dans le temps, des deux périodes du processus de raccordement.
• La figure 4 représente schématiquement la section d'entrée d'une installation, dans un second mode de réalisation de l'invention.
• La figure 5 est un diagramme indiquant, dans le temps, le déroulement des deux périodes du processus général de raccordement, dans le mode de réalisation de la figure 4.

But the invention will be better understood by the following description of some particular embodiments, given by way of example and shown in the accompanying drawings.

• The figure 1 is a diagram indicating, by way of example, the duration of the different steps of the general process of connecting two successive bands.
• The figure 2 schematically represents the inlet section of an installation, in a first embodiment of the invention.
• The figure 3 is a diagram representing the flow, in time, of the two periods of the connection process.
• The figure 4 schematically represents the input section of an installation, in a second embodiment of the invention.
• The figure 5 is a diagram indicating, in time, the progress of the two periods of the general connection process, in the embodiment of the figure 4 .

As indicated, the figure 1 is a diagram representing, on the abscissa, the time course of the various steps A to I of the general connection process, carried out, in a conventional manner, in the input section of a continuous online processing installation.

The figure 2 schematically represents the input section of an improved plant according to the invention, in a first embodiment.

As usual, the band to be treated can take place from one or the other of two unrollers 11, 11 'each associated with means 12, 12' of unwinding and straightening of the band and a shear trimming 13, 13 '. A switching device 14 makes it possible to introduce into the input section the band M or M 'coming, respectively, from one or other of the two unwinders 11, 11'.

According to the invention, the inlet section 1 is divided into two parts 3 and 4 between which is interposed an intermediate accumulator 5. After leaving the input section, the band passes, as usual, in an upstream accumulator 6 then in the processing section 7, which is followed by a downstream accumulator and the output section. The parts of the installation that follow the upstream accumulator 6 are not modified and have not been shown in the drawings.

The equipment necessary for joining two successive coils is distributed between the two parts 3 and 4 of the inlet section 1.

Thus, in the embodiment shown on the figure 2 , the first part 3 of the inlet section comprises temporary joining means 31 such as a stapler, associated with inlet and outlet side guides 32 and 33.

The intermediate accumulator 5 can be made in the usual way according to the length of band to be stored, this length being indicated below.

It is known that, in general, a tape accumulator consists of a set of stationary rollers and a set of moving rollers on which the tape passes, the movable rollers being mounted on a carriage which can be move to vary the accumulated tape length. The strip must remain tensioned between the fixed and moving rollers and that is why such an accumulator must be associated, normally, with two tensioners, for example with S-rollers, placed respectively upstream and downstream of the accumulator in the direction scrolling.

On the figure 2 , the intermediate accumulator 5 has been shown schematically by a movable roller 51 and two tensioners respectively upstream 52 and downstream 53.

The second part 4 of the inlet section 1 comprises, as usual, a welding equipment 41, for example by spark, associated with a double shear 42 and a planer 43. On the figure 2 these devices have been shown separately but we know that they can advantageously be grouped in the same machine. As a simple example, the French patent 2,756,504 of the same company discloses a spark-welding machine comprising two pairs of clamping jaws of the ends of the two strips M, M 'to be connected, which are respectively mounted on a fixed frame and on a mobile frame, a double shear consisting for example two pairs of blades or wheels movable transversely for shearing the ends of the two strips along two parallel lines and a planing tool mounted transversely sliding on the fixed frame.

Furthermore, the welding machine is associated, usually, with inlet side guides 44 and outlet guides 45 which make it possible to precisely position, in the machine, the two strips M, M ', in particular, for shearing. and the approximation of the ends to be welded.

The upstream accumulator 6 can be produced in any known manner and has therefore been schematized on the figure 2 by a single mobile roller 61 associated with two tensioners 62, 63.

The installation represented on the figure 2 thus allows to divide the connection process in two successive periods respectively carried out in the two parts 3 and 4 of the input section.

On the diagram of the figure 3 , as a function of the time indicated on the abscissa, the successive steps of the general process of connecting the two strips have been represented in an installation as represented in FIG. figure 2 and comprising, therefore, two successive periods separated by a passage time in the intermediate accumulator 5.

As indicated, the first section 3 of the installation differs from a conventional installation in that the electric welding machine is replaced by a temporary joining means such as a stapler 31. The first period of the process thus, on the one hand, the steps A, B, C, D, E of the corresponding preparation cycle P, as explained above with reference to FIG. figure 1 at the cut of the tail of the strip being unwound, the introduction of the next strip cut beforehand and the positioning of the two strips in the stapler and, secondly, two new steps L and M.

Indeed, in a step L, the two strips are stapled. This operation is faster than welding and may require, for example, 5 seconds.

The two bands are thus temporarily attached, the scrolling is restarted in a start step M which can last 5 seconds.

These two steps L and M therefore constitute a first phase S ₁ of the junction cycle taking place in the first period of the connection process.

For this first period, the overall time T ₁ of stopping of the scroll in the first part 3 of the input section can therefore be of the order of 50 seconds.

During this standstill time T ₁ , the treatment section (7) has been fed by the upstream accumulator 6 but, according to an essential characteristic of the invention, it has been fed in turn from the intermediate accumulator 5 so as to be maintained substantially at its maximum capacity.

The capacity of the intermediate accumulator 5 must therefore correspond at least to the length of tape traveling at the normal processing speed during the first stopping time T ₁ .

The tail of the first band returned to its running speed is temporarily attached to the head of the new band and therefore passes into the intermediate battery 5 to arrive in the second part 4 of the input section. Since, at this moment, the intermediate accumulator 5 has a reduced capacity, the transit time T ₂ of the temporary junction in this intermediate accumulator can be quite low, for example, 25 seconds.

It is then possible to carry out the second phase S ₂ of the junction cycle in the second part 4 of the input section.

The temporary junction must first be positioned in the welding machine in a step E 'which may take 10 seconds. The ends of the two strips being held by the clamping jaws of the welding machine, it is proceeded, in a step F ', shearing the two edges with evacuation of the staple and their welding, in a step G.

Finishing operations are then performed, such as planing the weld (step H) and then returning to normal speed (step I).

This second period of the connection process requires an overall time T ₃ of stopping in the second part 4 of the input section which can be of the order of 45 seconds.

Of course, as indicated by reference to the figure 1 this time can be extended if a notching (step J) and / or annealing of the weld (step K) is performed.

At the end of the step I or K, the running of the tape can resume at normal speed but the upstream accumulator 6 which fed the processing section must be reduced to its maximum capacity. For this, the speed of scrolling in the input section 1 is increased by for example, up to 700 or 800 m / min during the time required to fill the accumulator.

However, the scrolling must be stopped when the tail of this new coil arrives at the beginning of the input section 1 and, if the length of this new coil is too small, this moment may occur before the upstream accumulator 6 not completely filled.

The method which has just been described makes it possible to avoid such a disadvantage by splitting the connection process into two periods carried out in two different parts 3, 4 of the input section 1 and separated by a time interval T ₂ of variable duration.

Indeed, the overall run-stop time required for connection of two successive bands is divided into two periods, and therefore the time during which the processing section 7 must be fed by the upstream accumulator 6 is equal to either at the stop time T ₁ in the first part 3 of the inlet section, or at the stop time T ₂ in the second part 4.

Moreover, the intermediate accumulator 5 can maintain the upstream accumulator 6 at its maximum capacity during the stopping time T ₁ in the first part 3 and can then be filled during the stopping time T ₃ in the second part 4 of the input section so as to be at its maximum capacity when the tail of the new band arrives in the first part 3. There are thus multiple possibilities of managing the band scroll according to the length of the coils to integrate in the line and according to the respective capacities of the intermediate accumulator 5 and the upstream accumulator 6.

For example, as shown on the figure 3 , the tail of the new integrated coil in the line arrives at the beginning of the input section 1 at a time t ₄ . This instant t ₄ is shifted by a time T ₄ with respect to the moment t ₁ when the head of the new band M 'had left the first part 3 of the inlet section 1, after its provisional junction with the tail of the previous band M. This time T ₄ depends on the length of the new coil.

Thanks to the use according to the invention, of an intermediate accumulator 5, it is possible to stop scrolling again in the first part 3 to make the junction with a third coil, as soon as the intermediate accumulator 5 has a sufficient capacity to maintain the scroll downstream for the time T ₁ .

In practice, from time t ₁ where the head of the new band M 'is joined to the previous band M, the running speed in the first part 3 can be increased to fill the intermediate accumulator 5. The time necessary for this filling therefore corresponds to the minimum duration of the offset T ₄ between the respective passages of the head and tail of the new coil, which depends on the length thereof.

If necessary, for the integration of a short coil, it is possible to manage the operation of the accumulators 5, 6 so that the junction with a third coil possibly begins even before the time t ₃ is that is before the end of the second period T ₃ of the connection process. The two periods can indeed overlap since they are made in two different parts of the inlet section 1 separated by the intermediate accumulator 5.

Furthermore, the invention is not limited to the only embodiment that has just been described but may be subject to variants, for example for the distribution of equipment between the two parts of the input section.

Thus, in another embodiment shown on the figure 4 , the welding machine 41 is placed in the first part 3 of the inlet section 1, upstream of the intermediate accumulator 5. In this case, no temporary junction is necessary and the stapler 31 of the figure 2 is removed, the tail of the band M at the end of unwinding being electrically welded to the head of the new band M '. As usual, the welding machine 41 can be equipped with a double shear 42 making it possible, on the ends of the two strips, two parallel edges which are then close together for spark.

On the other hand, to reduce the duration of the stopping in this first part 3 of the inlet section 1, the planing operation is delayed, a planer 43 'being installed downstream of the intermediate accumulator 5, in the second part 4 of the inlet section 1. Indeed, it is possible, for example at reduced speed, to pass in the accumulator 5 the bead formed by the electrical welding of the ends of the two strips M, M ' .

Such an arrangement therefore requires the installation of a separate planer 43 'but allows, on the other hand, to remove the stapler. In addition, it is easier, in case of need, to integrate in the second part 4 of the inlet section a notching device 46 and an annealing furnace 47.

The diagram of the figure 5 indicates the durations of the different steps of the joining process in the case of an installation according to the figure 4 .

Since the welding machine 41 is placed, with the shears 42, in the first part 3 of the inlet section, the different stages A, B, C, D, E, F, G, of the welding process are the same as in the conventional process illustrated by the figure 1 . On the other hand, the planing is delayed and, after the welding of the ends opposite the two bands, it is ordered, in a step M, the restart of the line to return to normal speed.

The general connection process illustrated by the figure 5 therefore further comprises a preparation cycle P corresponding to the steps A to E and a junction cycle divided into two phases separated by the passage in the intermediate accumulator 5, respectively a first phase S ₁ corresponding to the steps F, G, M and in the first period of the process and a second phase S ₂ corresponding to the steps N, H, I and possibly J and K.

Since the final joining of the two bands is done and not simply stapling, the overall duration T ' ₁ of this first period of the joining process is a little greater than that of the first period in the case of the figure 3 , and may be in the range of 60 to 65 seconds.

As previously, the scrolling being resumed, the welded junction passes into the intermediate accumulator 5 and arrives in the second part 4 of the input section at a moment t'2, the passage time T ' ₂ being able to be simply 20 or 25 seconds in the at which time the intermediate accumulator 5 has a reduced capacity.

The running of the tape being stopped again, it is necessary to position the weld in the planer 43 '(step N) and then planing in a step H.

As has been indicated, such an embodiment is particularly advantageous if it is necessary to perform notching (step J) and annealing (step K).

In this case, the duration T ₁ of the first welding period may be greater than the duration T ' ₃ of the second planing period but is, in any case much less than the overall time previously required for the joining. In addition, the intermediate accumulator 5 makes it possible to replace, at least partially, the length of band supplied by the upstream accumulator 6 during the time T ' ₃ and, thus, to keep it at its optimum capacity.

We see that the invention has many advantages because it provides a great deal of flexibility in the management of the installation.

Admittedly, such an installation requires the addition of an intermediate accumulator, but the cost of this equipment is quickly offset by the improvement of the productivity of the installation whose load plan can be established in a much more flexible way thanks to the possibility of incorporating coils having variable lengths, possibly very short. In particular, insofar as the two periods of the joining process are entirely separate, it is conceivable, in the case of a very short coil, that the head and the tail of the latter are at the same time inside. of the intermediate accumulator, the two parts 3, 4 of the input section 1, being occupied by different bands.

Other variants would be possible, for example, by using another intermediate accumulator so as to divide the joining process into three periods.

Moreover, the invention is especially applicable to continuous strip stripping lines of steel but could also be adapted to other continuous line treatments.

Claims (13)

1. Method for managing the input into a continuous line processing plant of a new coil of a strip product wound in coils, including an input section (1) fed with successive coils and in which the tail of a coil (11), at the end of unwinding, is connected to the head of a next coil (11') to form a continuously running strip, an upstream accumulator (6), a processing section (7), a downstream accumulator and an output section, two consecutive strips (11, 11') being connected in the input section (1) of the plant in two cycles of successive stages, respectively a first cycle for preparing the ends, respectively tail and head of the two strips with a view to joining them and a second cycle for joining both facing edges of said ends, comprising bringing said edges close together in a welding machine (41) and finishing operations,
   method wherein the travel of the strip is stopped or, at least, slowed in the input section (1) for a period of time necessary for all the connection operations and the processing section (7) is supplied, during the stoppage or slowdown time, with a strip length set aside beforehand in the upstream accumulator (6) to continue processing at a normal running speed,
   characterised in that the second cycle joining the facing edges of the ends of the two strips (M, M') is performed in at least two parts of the input section (1), between which there is an intermediate accumulator (5) for setting aside a variable strip length, respectively a first part (3) in which the welding machine (41) is positioned so as to implement a first phase of the joining cycle, comprising joining the facing edges of the two consecutive strips (M, M') and a second part (4) in which a second phase of the joining cycle is implemented, comprising at least one finishing operation, the time needed for all the operations to connect the two strips (M, M') thus being divided into at least two periods (T₁, T₃), respectively a first period (T₁) corresponding to the first preparation cycle and to a first phase of the joining cycle and a second period (T₃) corresponding to a second phase of the joining cycle, said two periods (T₁, T₃) being separated by a time interval (T₂) of variable duration corresponding to the travel of the length set aside in the intermediate accumulator (5), in that the welding operation is performed at the end of the first period (T₁) in the first phase of the joining cycle, in that the tail of the first strip (M) is then passed into the intermediate accumulator (5) and it is welded to the head of the next strip (M'), and in that the travel is stopped again in the second part (4) of the input section (1) to carry out at least one finishing operation during the second period (T₃) corresponding to the second phase of the joining cycle.
2. Method for managing the input into a continuous inline processing plant of a new coil of a strip product wound in coils, including an input section (1) fed with successive coils and in which the tail of a coil (11), at the end of unwinding, is connected to the head of a next coil (11') to form a continuously running strip, an upstream accumulator (6), a processing section (7), a downstream accumulator and an output section, two consecutive strips (11, 11') being connected in the input section (1) of the plant in two cycles of successive stage, respectively a first cycle for preparing the ends, respectively tail and head of the two strips with a view to joining them and a second cycle for joining both facing edges of said ends, comprising bringing said edges close together in a welding machine (41) and finishing operations,
   method wherein the travel of the strip is stopped or, at least, slowed in the input section (1) for a period of time necessary for all the connection operations and the processing section (7) is supplied, during the stoppage or slowdown time, with a strip length set aside beforehand in the upstream accumulator (6) to continue processing at a normal running speed,
   characterised in that the second cycle joining the facing edges of the ends of the two strips (M, M') is performed in at least two parts of the input section (1), between which there is an intermediate accumulator (5) for setting aside a variable strip length, respectively a first part (3) in which the travel is stopped so as to implement a first phase of the joining cycle, comprising provisional joining of the facing edges of the two consecutive strips (M, M') and a second part (4) including the welding machine (41) and in which the final joining of the two strips and at least one finishing operation are implemented, the time needed for all the operations to connect the two strips (M, M') thus being divided into at least two periods (T₁, T₃), respectively a first period (T₁) corresponding to the first preparation cycle and to a first phase of the joining cycle and a second period (T₃) corresponding to a second phase of the joining cycle, said two periods (T₁, T₃) being separated by a time interval (T₂) of variable duration corresponding to the travel of the length set aside in the intermediate accumulator (5), in that the provisional joining of the tail of the first strip (M) to the head of the next strip (M') is implemented at the end of the first period (T₁) of the general connection process, in that the travel of the strip is then resumed to take said provisional joint into the second part (4) of the input section (1), passing through the intermediate accumulator (5), and in that the travel of the strip is stopped again during the second period (T₃) of the general connection process in order to carry out the actual welding operation itself and at least one finishing operation in a second phase of the joining cycle.
3. Management method according to any one of claims 1 and 2, characterised in that, before the end of unwinding of the first coil (11), strip lengths are set aside in the upstream accumulator (6) and in the intermediate accumulator (5), corresponding to the maximum capacity thereof.
4. Management method according to claim 3, characterised in that, during the first period (T₁) of the general connection process, the processing section (7) is supplied at normal speed from the upstream accumulator (6), and in that, at the same time, the passage into the upstream accumulator (6) from the intermediate accumulator (5) of a strip length able to replace at least one part of the length passing into the processing section (7) is controlled.
5. Management method according to one of the preceding claims, characterised in that, during the second period (T₃) of the general connection process, the processing section (7) is supplied at normal speed from the upstream accumulator (6), and in that the travel through the first part (3) of the input section (1) of the strip length necessary for restoring the intermediate accumulator (5) to its maximum capacity, is controlled.
6. Method according to one of claims 4 and 5, characterised in that the intermediate accumulator (5) is given a capacity corresponding at least to the strip length running in the processing section (7) at normal speed for the duration (T₁) of the first period of the general connection process.
7. Method according to claim 6, characterised in that, from the stoppage for joining the head of the new strip (M') to the tail of the preceding strip (M), the unwinding speed of the new coil is increased for filling, at least partially, the intermediate accumulator (5), so that, depending on the length of the new coil (11'), the tail thereof can be stopped in the first part (3) of the input section (1) to join it to the head of a third coil, after setting aside a strip length corresponding at least to the first period (T₁) of the general connection process.
8. Method according to one of claims 4 to 7, characterised in that the upstream accumulator (6) is given a capacity corresponding at least to the strip length running in the processing section (7) at normal speed during the second period (T₃) of the general connection process.
9. Method according to one of the preceding claims, characterised in that the filling rate of the intermediate accumulator (5) is managed in relation to the length of each new coil (11') so as to restore the upstream accumulator (6) to its maximum capacity after each period of the general connection process.
10. Method according to one of the preceding claims, characterised in that, at the end of the second period of the general connection process, the weld is annealed.
11. Plant for processing a strip product in a continuous line, including an input section (1) supplied with successive coils, with connection, through successive steps, of the tail of a coil (11) at the end of unwinding to the head of a next coil (11') to form a continuously running strip, an upstream accumulator (6), a processing section (7), a downstream accumulator and an output section fitted with means for discharging the coils at the end of unwinding, the input section (1) being fitted with means (13, 13') for preparing, at least by end cropping, the ends, respectively tail and head, of two consecutive strips and an assembly for joining said ends, including at least joining means (41) and means (43) for finishing the joint, characterised in that the input section (1) is divided into at least two parts between which there is at least one intermediate accumulator (5), respectively a first part (3) including at least means (13, 13') for preparing the tail and the head of two successive strips (M, M'), positioning means (31, 33) and welding equipment (41), and a second part (4) including at least means (43) for finishing the weld.
12. Plant for processing a strip product in a continuous line, including an input section (1) supplied with successive coils, with connection, through successive steps, of the tail of a coil (11) at the end of unwinding to the head of a next coil (11') to form a continuously running strip, an upstream accumulator (6), a processing section (7), a downstream accumulator and an output section fitted with means for discharging the coils at the end of unwinding, the input section (1) being fitted with means (13, 13') for preparing, at least by end cropping, the ends, respectively tail and head, of two consecutive strips and an assembly for joining said ends, including at least joining means (41) and means (43) for finishing the joint, characterised in that the input section (1) is divided into at least two parts between which there is at least one intermediate accumulator (5), respectively a first part (3) including at least means (13, 13') for preparing the tail and the head of two successive strips (M, M') and means (31) for the provisional joining of said tail and head and a second part (4) including at least welding equipment (41) associated with means (44, 45) for positioning and removing the provisional joint and means (43) for finishing the weld.
13. Processing plant according to one of claims 11 and 12, characterised in that the second part (4) of the input section (1) comprises means for annealing the weld.

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