EP0014140A1 - Device for cooling a longitudinally moving elongated product - Google Patents

Abstract

Device for cooling a long product while traveling, comprising an elongated tube traversed by a cooling liquid and in which also passes the product to be cooled. According to the invention, the tube 1 is internally equipped with a centering member 13 for the moving product, comprising a central passage 14 of diameter less than the inside diameter of the tube 1. Advantageously, the centering member 13 has longitudinal channels peripherals 16 distributed around the central passage 14 to facilitate the circulation of the cooling liquid. The invention makes it possible to improve the homogeneity of the cooling and preferably applies to products of fairly large format, such as steel bars which, because of their weight and their slow speed of movement, are more subject than others coming into contact with the inner wall of the tube.

Description

The present invention relates to a device for cooling a long moving product.

Devices of the type under consideration essentially comprise an elongated tube traversed by a cooling liquid (usually water) and through which also passes a product which takes a long time to cool.

The tube is equipped, at one end, with a coolant supply head and at the other with a separator whose role is to dissociate, at the exit of the tube, the product in movement from its liquid envelope.

Without being of application limited to particular industrial fields, such devices are used in particular in metallurgy, more specifically in the context of special heat treatments of long products at the end of rolling.

Despite the effectiveness of these devices, the homogeneity of the treatment is not always acquired depending on the product, its speed or its shape.

It appears, in particular, that the homogeneity of the heat treatment is appreciably better in the case of the cooling of crenellated round products (for example the bars comprising a helical rib) than in the case of smooth round products. It was by questioning the causes of this difference that the applicant considered the possibility of the product coming into contact with the scrolling with the inner wall of the tube.

It is in fact understood that, under these conditions, the coolant no longer has the capacity to be able to treat the product uniformly over its entire circumference.

The experimental verification made it possible to confirm the initial hypothesis: experience shows that indeed, fairly large diameter products, such as bars, have, given their fairly high weight and relatively reduced speed, inside the tube an arrow large enough to partially rest on the bottom of the latter. The reason why the crenellated bars treat better than their smooth counterparts, thus becomes clear: the ribs allow the passage of the cooling liquid under the bar.

In order to avoid the product coming into contact with the internal wall of the cooling device, it has already been proposed to have guide funnels (French patent 1,569,259), but these are not sufficient to ensure uniform cooling and it is necessary to provide coolant injection tubes all along the device. Guidance devices of more complex shape have also been proposed, making it possible to create a turbulence of the cooling fluid (German patent 2,556,383) or of elliptical section and displaceable in rotation around the axis of the tube (American patent 4,136,544).

All these devices could not be used in the case of high flow rates of cooling fluid (sheet of water circulating at high speed) because of the very high pressure drops which they introduce.

The object of the present invention is precisely to provide a device, avoiding the drawbacks of known devices which can be used for high flow rates of cooling fluid.

To this end, the subject of the invention is a device for cooling a long moving product comprising an elongated tube traversed by a cooling liquid and in which the product to be cooled also passes, fitted internally with means for centering the product constituted by tubular elements coaxial with the tube and having a central passage whose diameter is less than the internal diameter of the tube, said passage being preceded, in the direction of travel of the product, by an introduction cone, device characterized in that the means for centering have peripheral longitudinal channels, distributed around the central passage.

• - la figure 1 est une vue schématique, en coupe longitudinale, de l'ensemble du dispositif de refroidissement,
• - la figure 2 est une vue agrandie, en coupe longitudinale, montrant le détail d'une réalisation d'un organe de centrage,
• - la figure 3 est une vue, en coupe transversale, de l'organe de centrage, selon le plan AA de la figure 2,
• - la figure 4 représente, en coupe longitudinale, une variante de réalisation d'un organe de centrage.

The invention will be well understood and other aspects and advantages will emerge more clearly 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 longitudinal section, of the entire cooling device,
• FIG. 2 is an enlarged view, in longitudinal section, showing the detail of an embodiment of a centering member,
• FIG. 3 is a view, in cross section, of the centering member, along the plane AA of FIG. 2,
• - Figure 4 shows, in longitudinal section, an alternative embodiment of a centering member.

In 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 de liquide refroidissant 2, généralement de l'eau (et que l'on considèrera comme tel par la suite),
• - une tête d'alimentation 3, disposée à une extrémité du tube 1 qui injecte dans ce dernier l'eau reçue par une tubulure d'amenée 4,
• - à l'autre extrémité, un séparateur 5, destiné à récupérer l'eau à la sortie du tube et à l'évacuer par une sortie 6.

As shown in Figure 1, the cooling device includes:

• - an elongated tube 1, traversed, in the direction indicated by the arrows, by a stream of cooling liquid 2, generally water (and which will be considered as such below),
• a supply head 3, disposed at one end of the tube 1 which injects into the latter the water received by a supply pipe 4,
• - at the other end, a separator 5, intended to collect the water at the outlet of the tube and to evacuate it through an outlet 6.

The long product to cool, referenced 7, passes right through the device in a longitudinal direction. To this end, openings 8 and 9, centered on the axis 10 of the tube and formed respectively in the feed head 3 and in the separator 5, allow the free passage of the product while scrolling.

It will be recalled that the moving product 7 and the water jacket 2 which envelops it in the tube can circulate, either in "co-current", that is to say in the same direction, or in "against" current ", that is, in the opposite direction. Also, the arrowed indication of the displacement of the product 7 in the figure only underlines the fact that this product is not stationary, but scrolling without it being possible to prejudge the real direction of displacement.

It is also pointed out that, for the purposes of the figure, the length of the tube 1 has been deliberately reduced compared to its internal diameter. As an indication, the cooling tubes of the type considered are several meters long, generally of the order of 4 to 6 meters, while their internal diameter, which of course depends on the range of formats of the products to be cooled, however exceeds rarely about 10 cm. In this regard and for reasons of convenience, the tube 1 is generally not made in one piece, but in several elementary sections 11, for example of about 2 meters in length each, connected one after the other. by screw crowns, referenced 12.

According to the invention, the tube 1 has locally centering means 13. These centering means are constituted by a tubular element coaxial with the tube!, Which can advantageously be interposed between two consecutive sections 11 and which defines a central passage 14 of diameter smaller than the inside diameter of the tube 1. The guide of the product in movement 7 through the centralizer 13 is ensured by an insertion cone 15 produced by appropriate machining of the internal profile of the centralizer.

The following figures show the detail of an advantageous embodiment of the centering device.

We find in Figure 2 the centering device 13 interposed between two sections Il of the tube 1 and whose central passage 14, of diameter noted Øc less than the inner diameter Øt of the tube, is preceded by the introduction cone 15 which converges in the direction of displacement of the product to be cooled (not shown in the figure).

According to a characteristic of the invention, periphery channels risks 16 have been provided longitudinally in the thickness of the centering device 13.

These channels 16, visible in cross section in Figure 3, have the role of facilitating the circulation of the cooling water. In their absence, in fact, the entire flow would be forced to pass through the central passage 14 already substantially occupied by the moving product. It is understood under these conditions that the centralizer can, if necessary, disturb the proper functioning of the cooling system by creating in the stream of water significant pressure drops and even higher than the diameter Øc of the central passage 14 is close to the diameter of the moving product, in other words, the higher the centering is better ensured.

In the embodiment described, the invention thus succeeds in reconciling the two opposing imperatives that are, on the one hand the centering of the product in movement which ensures the homogeneity of its cooling and, on the other side, the passage of water whose more or less "easy" character conditions the efficiency of this cooling.

According to a preferred embodiment, making it possible to minimize the pressure losses of the water circulation, the sum of the sections of the central passage 14 and the peripheral channels 16 is substantially equal to the interior section of the tube 1.

In the example described, 0̸t = 63 mm, 0̸c = 45 mm, and the diameter of the peripheral channels 16, noted 0̸p, is 14 mm. In this case, the aforementioned variant is produced using a centralizer 13, the peripheral channels 16 of which are, as shown in FIG. 3, ten in number.

Referring again to Figure 2, we see that, in accordance with a feature of the invention, the peripheral channels are not parallel to the axis 10 of the tube, but slightly inclined with a downward slope in the direction of circulation some water.

The set of peripheral channels 16 thus gives the cooling water a circulation converging on the product, which makes it possible to reconstitute in good conditions downstream of the centralizer the liquid layer which envelops the product to be cooled.

According to another advantageous variant, the channels 16 are produced so that their outlet ends 18 have an angular offset around the axis 10 relative to the corresponding inlet ends 19. It is understood that this embodiment gives circulation of water, at the outlet of the channels, an overall gyratory movement around the product to be cooled.

Under these conditions, the centralizer 13 then fulfills an additional function. "deviator" which acts on the liquid envelope surrounding the product, by transforming the rectilinear circulation of this envelope, upstream of the centralizer, into a circulation of helical type, downstream of the centralizer. One advantage of this variant is to allow, while maintaining a given relative speed of water with respect to the product, to increase the residence time of the water in the tube, or, at a given residence time, to reduce the length of the tube.

Another advantage lies in the fact that, by centrifugation effect, the separation of water and product at the outlet of the tube is appreciably facilitated.

This variant embodiment also accommodates a radial offset from the outlet ends 18 towards the axis 10, which makes it possible, as previously, to cause the water to converge on the product at the outlet of the channels. Furthermore, the channels 16 can be rectilinear or, preferably, curved, which allows a greater angular offset of the outlet ends 18 without however causing sudden changes in the direction of water circulation.

As will have already been understood, the variant illustrated in FIG. 2 is preferably suitable for water-product circulation in "co-current".

FIG. 4 shows another embodiment which can be described as "universal" since it accommodates both a circulation of the "co-current" type and "counter-current" type. To this end, the central passage 14 of the centering device is extended on one side as on the other by an introduction cone 15 (respectively 15 ′) which guides the product, whatever the direction of movement of the latter. . Furthermore, the peripheral channels 16 are shaped like an open V, which makes it possible to converge the cooling water on the product at the outlet of the centralizer, regardless of the direction of water circulation.

In the production of a centralizer according to the invention, care will be taken that the head of the moving product, during its passage, cannot abut against part of the centralizer.

To this end, the introduction cone 15, which precedes the central passage 14, is preferably dimensioned so that its large base has a diameter at least equal (advantageously greater) to the internal diameter 0t of the tube 1. This leads to as a general rule, to provide for practical reasons an annular groove 20 (20 ') at the entrance to the centralizer as clearly shown in Figures 2 and 4.

Although generally applicable to any product that is long in movement, it It is clear that the invention finds a preferential use for products of fairly large formats, such as steel bars which, by their weight and their low speed of movement (2 to 4 m / second) are more subject than others coming into contact with the wall of the cooling tube.

Claims (6)

1 ° Device for cooling a long moving product comprising a tube, traversed simultaneously by a cooling liquid and by the product to be cooled and internally equipped with product centering means constituted by tubular elements, coaxial with the tube and having a central passage of diameter less than the internal diameter of the tube, said passage being preceded, in the direction of travel of the product, by an introduction cone, device characterized in that the centering means have peripheral longitudinal channels, distributed around the central passage. 2. Device according to claim 1, characterized in that the sum of the sections of the central passage and the peripheral channels is substantially equal to the interior section of the tube. 3 ° Device according to claims 1 or 2, characterized in that the peripheral channels are inclined so as to present, at least in the vicinity of their outlet ends, a downward slope in the direction of circulation of the cooling liquid. 4. Device according to claims 2 or 3, characterized in that the peripheral channels have an outlet end offset angularly around the axis of the tube relative to their corresponding inlet end. 5 ° Device according to claim 4, characterized in that the peripheral channels have a curved path. 6 ° Device according to claims 3, 4 or 5, characterized in that the peripheral channels have, in longitudinal section, a V-shaped profile.

Images