EP0013230A1 - Device for removing a fluid from the surface of a long and continuously moving product - Google Patents

Abstract

Device for separating a long product in movement 8 from a liquid envelope which accompanies it in the form of a coaxial jet, constituted by a box having a lateral opening 6 through which the jet surrounding the product penetrates, a lateral orifice 10, in the alignment of the opening 6, to allow free passage in a straight line of the product 8 while scrolling and a lower outlet 7 for the evacuation of the recovered liquid. The separator according to the invention is characterized in that the box 5 comprises means, such as a perpendicular jet 13, for causing the jet surrounding the product to shear, preferably in combination with means for weakening the jet prior to its shear. The separator allows an efficient interruption of the jet surrounding the product as well as the recovery and evacuation of the liquid thus collected. It finds its application as a terminal element of a device for cooling metal bars at the end of rolling or for products during continuous casting.

Description

The need for such a device is encountered for example at the outlet of a cooling device essentially comprising a tube traversed by a cooling liquid (usually water) and in the axis of which also circulates a product which is long to cool. The tube has, at one end, a coolant supply head and at the other end, a separator whose role is to rid, at the exit of the tube, the product in flow of the liquid jet which the envelope.

Without being of application limited to certain particular industrial fields, such devices are encountered in particular in the steel industry, for example in continuous casting or more especially in the context of special heat treatments, for rapidly and vigorously cooling long products at the end of rolling. Faced with these cooling requirements, we quickly realized the need to provide, at the outlet of the tube, an element which, while ensuring free passage for the product moving in a straight line, allows recovery and evacuation coolant by interrupting, for reasons of space preferably over the shortest possible distance, the liquid envelope, which would otherwise exit the tube in a powerful jet which can easily reach ten meters and which, moreover, would make more difficult to control the cooling process.

To do this, it has already been proposed a separator consisting of a simple box, or box, recovery. This box, open at its lower part for the evacuation of the recovered liquid, has a lateral opening through which the liquid jet coaxial with the product penetrates and, in alignment with this opening, a lateral orifice sized so as to allow the free passage of the product while scrolling while obstructing the liquid jet which envelops it. This solution, which is admittedly advantageous by its simplicity, nevertheless has drawbacks, in particular with regard to the sealing of the box at the level of the orifice for the passage of the product. In fact, this orifice cannot be made as close as desired to the diameter of the product to be cooled, so that the annular slot, necessarily present between the two, constitutes for the jet a preferred escape route, thus penalizing, and very sensitive, the jet interrupt function that we wanted to assign such a boot.

It has also been proposed, for example in French patent 2,226,221, American patent 1,874,959 and German patent 2,556,383, in order to improve the efficiency of such separators and in particular, to minimize the amounts of water entrained outside, apply a shearing effect to the jet surrounding the product using a secondary jet making an angle with the main jet. However, this shearing effect is not always sufficient, in particular in the case of main jets having a large amount of movement, to avoid any outflow of water from the separator.

The object of the present invention is to provide a separator designed so as to be able to effectively interrupt the liquid jet at the outlet of the tube while ensuring the free passage of the product while scrolling.

To this end, the subject of the invention is a device for separating a long product in movement from a liquid jet which envelops it, constituted by a box having a lateral opening through which the product and the jet surrounding it penetrate, a lateral orifice in alignment with said opening to allow the free passage of the product and a lower outlet for the evacuation of the recovered liquid, the box comprising means for causing a shearing of the jet between the inlet opening of the jet surrounding the product and the orifice for the passage of the latter, device characterized in that the box internally comprises means for weakening the liquid jet surrounding the moving product and consisting of at least one element having an axial recess for the free passage of the product in scrolling and achieving a reduction in the thickness of the jet surrounding the product.

By the qualifier "secondary", we mean to distinguish the shear jet from the jet enveloping the product, which can be described as "main".

In addition, the expression "at least one secondary jet" is intended to reserve the possibility of several successive jets arranged one after the other, along the axis of the previously defined openings.

Furthermore, it is useful to clarify for the understanding of the invention that it is not a matter of locally creating a sort of annular screen surrounding the product and which could be produced by a plurality of regularly distributed radial secondary jets around the axis of the openings and competing at the same point on the latter. It is rather a question of causing a shearing of the main jet which one wants to interrupt, that is to say

To this end, one can use for example, a nozzle, nozzle, etc ... or a simple frustoconical ferrule, converging in the direction of propagation of the jet and in the axis of which the product passes freely in movement, but whose The narrowest passage section has, of course, a diameter smaller than that of the jet.

This reduction in thickness can also be achieved by deflecting the peripheral annular layer of the main jet without generally causing a substantial pressure drop. The decrease in the amount of movement then takes place only by a decrease in the flow rate of the main jet. Such a peripheral deflection can be obtained by a deflector constituted, for example as before, by a frustoconical ferrule placed on the passage of the product in movement but whose convergence is, this time, oriented in a direction opposite to that of the propagation of the jet main. Of course, the small open base of the deflector necessarily has a smaller section than that of the main jet, the difference between the two determining the thickness of the deflected annular layer.

It is pointed out, however, that, for reasons which will appear clearly in the remainder of the description, this last variant is less well suited than the first when the product in movement and the liquid envelope circulate in the same direction.

• - à briser le jet principal par cisaillement au moyen d'un jet secondaire qui lui est perpendiculaire,
• - de préférence et préalablement à l'action de cisaillement, à placer sur le parcours du jet principal un ou plusieurs organes successifs ayant pour fonction d'amollir ou, si l'on préfère, d'affaiblir le jet principal,
• - enfin, à enfermer le tout dans un caisson servant à la collecte et à

As will have already been understood, the present invention consists of its main characteristics:

• - to break the main jet by shearing by means of a secondary jet which is perpendicular to it,
• - preferably and prior to the shearing action, placing one or more successive members on the path of the main jet, the function of which is to soften or, if preferred, to weaken the main jet,
• - finally, to enclose everything in a box used for collecting and

Incidentally, the product drying is perfected at the outlet of the casing, by blowing means directing on the product at least one gaseous jet, for example air.

• la fig. 1 est une vue schématique en coupe axiale d'un dispositif pour le refroidissement de barres métalliques en défilement équipe d'un séparateur terminal conforme a l'invention,
• les fig. 2, 3 et 4 représentent chacune, en coupe axiale, une variante de réalisation du séparateur conforme à l'invention,
• . les fig. 5 et 6 illustrent schématiquement le mode d'action des moyens selon l'invention pour affaiblir le jet principal.

The invention will be better understood and other aspects and advantages will be more clearly seen in the light of the description which follows, given with reference to the plates of attached drawings in which

• fig. 1 is a schematic view in axial section of a device for cooling metallic bars while traveling, equipped with a terminal separator according to the invention,
• fig. 2, 3 and 4 each represent, in axial section, an alternative embodiment of the separator according to the invention,
• . fig. 5 and 6 schematically illustrate the mode of action of the means according to the invention for weakening the main jet.

In all the figures, the same elements are designated by identical references.

• - un tube allongé 1 parcouru, dans le sens indiqué par les flèches, par un courant 2 de liquide de refroidissement que l'on supposera être de l'eau,
• - une tête d'alimentation 3 disposée à une extrémité du tube 1 recevant l'eau par une tubulure d'entrée 4 et l'injectant dans le tube et,
• - à l'autre extrémité, un séparateur 5 recevant le jet d'eau à la sortie du tube par une ouverture latérale 6 et destiné à interrompre ce jet, à recueillir l'eau ainsi récupérée et à l'évacuer par le bas par une sortie 7.

As shown in fig. 1, the cooling device comprises

• - an elongated tube 1 traversed, in the direction indicated by the arrows, by a stream 2 of coolant which will be assumed to be water,
• a supply head 3 disposed at one end of the tube 1 receiving the water through an inlet pipe 4 and injecting it into the tube and,
• - At the other end, a separator 5 receiving the water jet at the outlet of the tube through a lateral opening 6 and intended to interrupt this jet, to collect the water thus recovered and to evacuate it from below by a exit 7.

The cooling bar 8 crosses the device right through and in a rectilinear direction passing along the axis 11 of the tube 1. Openings 9 and 10 formed respectively in the feed head 3 and in the separator 5 allow free passage of the bar 8. It will be recalled that the orifice 10 of the separator is produced in alignment with the opening 6, this in order to ensure the crossing of the bar 8 in a straight line. The opening 6 and the orifice 9 are therefore coaxial and their axis merges with that of the tube designated at 11. It is also recalled that the cooling of the bar takes place essentially during its passage through the tube 1 by direct contact with the water jacket 2 which envelops it and which circulates at high speed.

It is pointed out in this regard that the bar 8 and the cooling jacket 2 can circulate, either "co-current", that is to say in the same direction, or

This secondary jet 12 can be gaseous, or preferably liquid, for example water. In this case, the nozzle 13 may advantageously consist of the outlet end of a pipe mounted as a bypass on the supply of cooling water serving the supply head 3.

The position of the nozzle 13 around the axis It does not matter. The figure shows it implanted through the upper part of the box 5 so that the shear jet 12 is oriented vertically, thus benefiting to the maximum from the effect of gravity, but it could just as easily have been implanted at through lateral partitions situated in the planes parallel to the plane of the figure.

When the main jet has a large amount of movement, as is the case for the heat treatment of long products at the end of rolling, the power of the secondary jet, necessary to obtain an effective shearing effect, could be as it would be feared, first some difficulties in guiding the product, by deflection of the head at the time of its introduction into the separator, then a folding of the product (especially for small diameter products) instead of impact of the jet. It is therefore preferable to be able to operate with a secondary jet of moderate impulse, which implies, all other things being equal, to act on a previously weakened main jet. One sees here appearing the interest of the means for softening the main jet, previously mentioned, and placed upstream of the shear jet in the direction of propagation of the main jet.

A priori, it is correct to think that, the more the number of successive softening means, the better the final result obtained.

In fact, as a general rule, a succession of two softening means suffices to soften the jet so that, after shearing, almost all of the water is recovered in the separator.

3 The following figures illustrate several variant embodiments

In FIGS. 2, 3 and 4, the main jet has not been shown so as not to overload them. As can be seen, the means of prior weakening of the main jet can be simple ferrules 14, of frustoconical shape and surrounding the product 8. These ferrules can be maintained by any appropriate support structure, such as clamps, etc. ... In the examples described, the support structures consist of partitions 15, arranged perpendicular to the axis of the openings 6 and 10. These partitions are fixed to the upper face of the box 5 and left free at their inner end . They have an orifice 16 for the passage of the product 8 and the ferrules 14 are attached to the edges of these orifices.

We realize _. thus a box 5` partitioned into several successive compartments, aligned along the moving product and each recovering a fraction of the water constituting the main jet which leaves the tube 1 and whose evacuation is ensured by the outlet funnel 7 .

In principle, the relative positions between the ferrules 14 and the nozzle 13 can be reversed. However, the results are all the better (absence of water projection through the orifice 10) that, for a given number of successive ferrules 14, the number of ferrules interposed between the outlet of the tube and the shear jet is large .

Thus, in the case of a box with three compartments (therefore with two successive ferrules 14) as shown in the figures, the nozzle 13 located in the compartment furthest from the tube gives better results than if it were placed in the middle compartment and, in this case, even better than if it were located in the first compartment into which the tube 1 opens.

In addition, a number of successive rings equal to or close to two is suitable in the majority of cases. Under these conditions, the main jet is entirely interrupted in the box 5. Below this number, the quantity of residual water gushing out through the orifice 10 is no longer negligible. Beyond this, the means often become overabundant and penalize the cooling device due to the additional unnecessary length that results.

We will now describe some possible arrangements of these means of prior reduction of the main jet and their mode of action on the latter.

petite base présente un diamètre inférieur à celui du jet, jouent le rôle J'un organe de perte de change en laminant le jet principal qui les traverse axialement. Cette variante de réalisation apparait bien adaptée à une circulation produit en défilement-eau de refroidissement en "co-courant", car les viroles constituent alors à l'égard du produit en défilement un cône d'introduction qui facilite le guidage de la tête du produit lors de son passage au travers de la boîte.i A first arrangement consists, as shown in fig. 2, to dispose

small base has a diameter smaller than that of the jet, play the role of a foreign exchange loss member by laminating the main jet which passes through them axially. This variant of embodiment appears to be well suited to a circulation produced in scrolling-cooling water in "co-current", since the ferrules then constitute, with respect to the scrolling product, an introduction cone which facilitates guiding the head of the product as it passes through the box.

Furthermore, such an arrangement has another advantage: as shown in the enlarged view of FIG. 5, the ferrule 14 fulfills, with respect to the jet (referenced 17), an additional reflection function by causing a part 18 of the water in the main jet to be turned back, a large fraction 19 of this turned part being then folded down on the jet upstream of the shell. This "folded" portion 19 disturbs the jet before rolling and thus contributes favorably to its weakening. It is easy to understand that the ferrule 14 fulfills its role of reflector only if its large base through which the jet 17 has a diameter greater than that of the jet.

A second possible arrangement is illustrated in FIG. 3. This variant is characterized by an arrangement of the frustoconical ferrules 14 so as to make them divergent in the direction of propagation of the main jet. This time, the reduction in thickness of the latter, is no longer done by rolling and reflection as in the previous variant but, as clearly shown in the enlarged view of FIG. 6, by deflection of a peripheral annular layer 20. This deflection role is of course filled by the ferrule 14 which has a small base of diameter smaller than that of the jet and whose beveled end 21 acts in a way, at the like an annular knife which "peels" the jet at its periphery. The peripheral annular layer 20 thus cut is then deflected by passing over the external face of the shell. For the reasons mentioned above, it is understood that such an alternative embodiment is, this time, better suited to a product-water circulation of the "counter-current" type.

coaxiales assemblées par leur petite base.Another possible arrangement is shown in FIG. 4. This variant embodiment, which can be described as "universal", since it accommodates both "co-current" and "counter-circulation" circulation current ", is characterized by the fact that the means of weakening the

coaxial assembled by their small base.

It should be noted that, whatever the variant used, there is a substantially improved and more regular operation of the separator 5, when an opening is made in it, near the end of the nozzle. 13. It therefore appears beneficial to provide, in the vicinity of the shear jet, an air intake which has been shown in FIG.

It should be understood that, in spite of an effective interruption of the main jet in the box, a slight flow rate of flow generally escapes through the passage opening 10. This leakage flow rate is moreover inevitable in the case of circulation at "co-current", because the moving product then carries with it residual moisture in the form of a thin liquid film or, at best, droplets which remain attached to the surface. Taking into account the surface temperature of the product after cooling (around 200 ° C), this residual moisture is eliminated naturally after a few seconds. However, due to the high speed of movement of the product, the humidity accompanies the latter over a fairly appreciable distance and one may wish to eliminate it as soon as it leaves the box.

This is achieved, in accordance with a variant of the invention, by externally equipping the box with additional drying means by gas blowing.

The blowing jet can be single or multiple, for example a plurality of radial gas jets which converge at the same point of the product at the outlet of the box and which form a gas disc around the product. This gaseous disc eliminates the residual moisture by mechanical effect due to the blowing itself, possibly associated with a thermal effect if the gas is to be preheated. The latter can be of any kind. For obvious reasons of convenience, air should preferably be used. An exemplary embodiment of these additional drying means is illustrated in FIG. 2. As can be seen, it is a simple circular pipe 23 surrounding the product to be dried 8 and disposed outside the box 5 in the immediate vicinity of the 'passage orifice 10. The pipe 23 is secured to the box by means of fixing flanges 24. This pipe is supplied by the pipe 25 with pressurized air from a source not shown and the blowing on the product 8 s' performs through a plurality of directed radial outlet nozzles 26

Finally, in the case of the so-called "universal" variant (FIG. 4), it is easily understood that the only necessary characteristic of these weakening means consists in assigning them an internal profile of) convergent-diverging shape.

Likewise, the means for additional drying of the product at the outlet of the box can implement other known principles for removing residual moisture than those described, for example by absorption, suction, etc. In addition, other variants can be chosen to produce the gas blast drying means. Indeed, it is not essential that the blowing takes place perpendicular to the product. It is thus possible to modify the inclination of the nozzles 26 at will (FIG. 2), for example so as to direct the gaseous jets onto the passage orifice 10 of the box. The blowing thus causes a gas barrier which thwarts, at the source, the leakage rate of the main jet. Conversely, the nozzles 26 can be oriented in a direction opposite to the previous one, which has the effect of forming around the product to be dried a gaseous sleeve which promotes, by convection, the elimination of residual moisture. Of course, the annular pipe 23 can be equipped with several series 5 of nozzles of different inclinations, in order to simultaneously implement the drying mechanisms mentioned above.

est le cas notamment en coulée continue des métaux, par exemple de l'acier, où le refroidissement de la barre coulée dans l'étage dit de "refroidissement secondaire" de l'installation peut s'effectuer par une chemise d'eau canalisée dans un manchon entourant la barre et circulant en contact avec la surface de cette dernière.Furthermore, the separator according to the invention applies not only to cooling long products at the end of rolling, but to any other industrial field in which it is advantageous to eliminate quickly a liquid film on the surface of a product

This is the case in particular in continuous casting of metals, for example steel, where the cooling of the casting bar in the so-called "secondary cooling" stage of the installation can be carried out by a jacket of water channeled in a sleeve surrounding the bar and circulating in contact with the surface of the latter.

Claims (9)

1 - Device for separating a long product from a flow of a liquid jet which envelops it, consisting of a

a side opening through which the product enters and

a lateral opening in alignment with said

allow the free passage of the product and a lower outlet for the evacuation of the recovered liquid, the box comprising means for causing a shearing of the jet between the inlet opening of the jet surrounding the product and the orifice for the passage of the latter , device characterized in that the box internally comprises means for weakening the liquid jet surrounding the product in travel and constituted by at least one element having an axial recess for the free passage of the product in travel and achieving a reduction in the thickness of the jet surrounding the product. 2 - Device according to claim 1, characterized in that the element reducing the thickness of the jet has an axial recess of profile converging in the direction of propagation of the jet and whose two ends by which penetrates and leaves the jet surrounding the product , have diameters respectively greater and less than the diameter of the jet. 3 - Device according to claim l, characterized in that the element reducing the thickness of the jet has a diverging external profile in the direction of propagation of the jet and in that the end of its axial recess through which penetrates the jet has a diameter smaller than that of the jet. 4 - Device according to claim I, characterized in that the means for weakening the jet surrounding the moving product are interposed between the inlet opening of the jet and the shearing means. 5 - Device according to one of claims 1 to 4, characterized in that it is equipped externally, in the immediate vicinity of the passage orifice, of additional drying means of the product in movement. 6 - Device according to claim 5, characterized in that the additional drying means are constituted by blowing means directing on the product at least one gas jet. 7 - Device according to claim 6, characterized in that the blowing means consist of a circular pipe surrounding the product, comprising a gas inlet pipe under pressure and a plurality of outlet nozzles directed towards the product. 8 - Device according to claims 1 or 5, characterized in that the box has an air intake in the vicinity of the shear jet. 9 - Device according to claim 1,

means for shearing the jet consist of at least one secondary jet directed substantially perpendicularly to the common axis of the inlet opening of the jet and of the orifice for the passage of the moving product.

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