MXPA99008792A - Cooled basket for steel plants - Google Patents

Abstract

Basket to manipulate scrap in cooperation with an arc furnace (11) and with means to pre-heat the scrap by means of the fumes from the fourth hole (14), the basket being able to be associated with a movable covering system (16) and including a containing body, a bottom equipped with toothed lower closing means which may be momentarily opened, and lateral extensions for moving and positioning the basket, the containing body comprising a first upper part (10a) which acts as a buffer store to temporally increase the capacity of the basket (10) and a second lower part (10b) to contain the scrap, with a capacity substantially mating with the volume of the load of the melting furnace (11) which it has to feed, wherein the second lower part (10b) is associated with cooling means.

Description

COOLED BASKET FOR STEEL PLANTS FIELD OF APPLICATION This invention relates to a cooled basket for steel plants, as described in the main claim. The cooled basket according to the invention is used for loading and subsequently discharging scrap in cooperation with electric furnaces or other plants for the melting of metals. The cooled basket according to the invention is suitable for cooperating with plants for the preheating of scrap using the extraction vapors generated by the oven, and in a convenient manner, with systems that automatically manage the operations of pre-heating, placing, discharge in the furnace, and relocation.

STATE OF THE ART In foundry plants, in steel works that use systems to load the furnace of a discontinuous type, the state of the art covers the use of containers, known as baskets, which are filled with scrap metal to be sent to casting, they are emptied into the furnace, and then returned to the area where the scrap is loaded. These baskets include, in the lower part, elements that can be opened momentarily, such as leaves, teeth, valves, or the like, which open when the basket is placed in correspondence with the mouth of the oven, to let out the contained scrap in. It is also well known in the state of the art that, in order to reduce casting times, and to improve the efficiency of the first steps of the cycle inside the furnace, the scrap in the basket, before being unloaded, is subjected to pre-heating by using the vapors that come out of the oven. These vapors are usually transported to the appropriate spaces where the baskets are to be found; the latter are gradually removed, filled with hot scrap, and then returned full of cold scrap. The use of tower-type containers is also known; they are placed on movable trolleys near the melting furnace, and can be moved from a preheated position to a position where the hot scrap is discharged into the furnace. These containers are loaded either by conveyor belts, which are expensive and also occupy a considerable space, or by baskets manipulated by bridge cranes that discharge the scrap from above the container itself. If the container is loaded from above, very high sheds are required, which are not usual, and these require heavy and expensive structures that are made for that purpose. The preheating process brings with it a plurality of advantages, because the furnace is fed in this way with scrap already at the correct temperature. However, when the previous heating is done in the basket, it also brings with it some disadvantages caused by the excessive and dangerous overheating of the walls and the bottom of the basket. Given the high temperatures of the vapors that come to surround the basket, and possibly circulate inside it, there are considerable increases in temperature, including in the containment structure, which involves operational problems in the handling and movement of the basket. Moreover, along with the vapors, dust, slag, and other dirt are also transported inside the basket and as they pass through the scrap, they can cause the pieces of scrap to adhere to each other, and consequently, difficulties in the unloading of the scrap from the basket to the oven. ~ When the scrap is discharged into the furnace, it falls violently, causing immense bursts of heat to escape from the furnace itself, impacting the basket and causing additional unwanted damage, moreover, during the discharge of plentiful amounts of dust, particles and other polluting substances escape from the furnace, and contaminate the_ area around the mouth of the oven. An additional problem with scrap baskets as known in the prior art refers to handling and handling times that extend end-to-end cycle times. Still another problem is the low efficiency of the transfer of heat energy from the vapors to the scrap. The applicant does not know scrap baskets used to load casting systems that can obviate all the aforementioned drawbacks. The state of the art includes US Pat. No. US-A-5, 106, 063, which describes a cooled container for scrap, for the purpose of discharging in a foundry furnace. This container substantially comprises an internal enclosure structure, of a cylindrical shape, and made of metal, supported by an external support structure consisting of a plurality of tubular elements, configured on the circumference and reciprocally separated, inside of which the fluid flows Cooling . The bottom of the container consists of two half portions that can be opened to discharge the scrap inside the oven; these are also equipped with a cooling system with circulating fluid. Although this solution gives a very efficient cooling of the scrap container, and a satisfactory previous heating cycle under normal operating conditions, it may not be as efficient in particular circumstances, and may give rise to different drawbacks during the maintenance operations and / or the replacement of the components. In fact, this cooling system comprises a single circuit for the circulation of the cooling fluid, and therefore, it is impossible to cool the different component parts of the container (walls and bottom) in a differentiated manner, when this is necessary and / or convenient , due to the different prevailing temperatures. What is more, under certain operating conditions, the separate configuration of the tubular elements within which the cooling fluid circulates, can cause a cooling effect on the container that is not uniform, and consequently, damage the container. Additionally, the continuity of the internal enclosure structure of the container substantially restricts its thermal expansion, and this can become a problem in view of the fact that this structure is continuously exposed to extremely high temperatures. This continuity also makes the operations to maintain or restore the container more complex and difficult, because it is necessary to intervene on the entire structure of the enclosure. Moreover, in the event that the scrap introduced in the basket becomes entangled, or takes an undesired position that could create empty spaces inside the basket, it becomes impossible to load the basket with the desired amount of scrap. The container proposed by the Patent of the States United States of America Number US-A-5, 106, 063, moreover, once again includes the aforementioned drawbacks with respect to environmental contamination when the scrap is discharged into the furnace, the optimization of handling times and of the cycle from end to end, and the exploitation of the thermal potential of the vapors used for the previous heating. Accordingly, the present applicant has designed, tested, and incorporated this invention to overcome the drawbacks of the state of the art, and to achieve additional advantages.

DISCLOSURE OF THE INVENTION The invention is described and characterized in the main claim, while the dependent claims describe variants of the idea of the main mode. The purpose of the invention is to provide a basket for use in operations to load / unload scrap, in cooperation with an electric furnace in steel plants, which will allow the scrap to be heated directly by vapors coming out of the fourth hole of the furnace, and at the same time, all operations are optimized in order to reduce end-to-end time to a minimum in technology. One of the purposes of the invention is also to provide a basket equipped with a cooling system, which is differentiated in its different structural parts, which eliminates overheating even in correspondence with the elements on the bottom of the basket that can be opened from a momentary way. A further purpose of the invention is to obtain a system that can limit environmental pollution caused by the leakage of dusts, incandescent particles, and other contaminants in the area around the furnace, during the discharge step, and in the area around the furnace. the basket itself during the pre-heating steps.

Another purpose is to limit to a minimum the escape of vapors and heat into the environment surrounding the furnace during the waste discharge steps, and to exploit up to a maximum the heat energy of the previous heating vapors. An additional purpose is to simplify the handling of the basket, to obtain an organic operating cycle substantially without useless wasted times, and at the same time without using the usual bridge crane element, except for as long as is strictly necessary, and when they are free of other activities. The invention also has the purpose of creating a coordinated structure consisting of the basket and movable elements to move the basket towards and away from the oven; This structure includes automatic systems for reciprocal connections, and automated phases that condition all operations. Still another purpose of the invention is to avoid the need to raise to excessively high levels, the tracks of the bridge cranes that have to handle the baskets, as in the case of stationary preheating containers. A further purpose of the invention is to ensure an efficient descent of the scrap into the furnace during the discharge step, ensuring the best possible seal to prevent possible leaks and leaks into the environment, both from heat and dust or other contaminants. It is also a purpose of the invention to exploit as much heat energy as possible from the vapors passing through the basket during the previous heating step. Another purpose of the invention is to reduce the times of operations to maintain and / or restore the structure of the basket, while simplifying these operations. The cooled basket according to the invention consists substantially of an open top container, which can be associated with a coupling covering system of a normally cylindrical cross-section or the like. According to a variant, the basket has a shape turned outward, towards the bottom to assist the scrap to exit during the unloading step. The chilled basket has an upper part which functions substantially as a storage and security area, a lower part defining the area containing the scrap, and a bottom equipped with a momentarily open containment element. The function of the storage area and superior security is to temporarily increase the capacity of the basket during the unloading step, in the event that, during this step, the scrap becomes entangled or improperly arranged, and therefore, can not occupy all the space available in the underlying area that is intended for scrap, or in the case where the scrap has a lower bulk density. The underlying space is intended to contain the correct amount of scrap that is to be discharged into the furnace for each cycle, and the volume of the bottom substantially defines the capacity of the layette. According to the invention, the upper part, or the safety part, includes a wall consisting of a bundle of adjacent tubes, in which the cooling fluid circulates, normally water, according to a first embodiment, the adjacent tubes They have a vertical development, and are part of the structure of the basket According to a variant, the adjacent tubes are configured on a horizontal plane.The lower part of the basket that defines the area containing the scrap, has a first wall internal, and associated with it, there is a second external wall consisting of adjacent tubes, where the cooling fluid circulates.In a first mode, the adjacent tubes have a vertical development.According to a variant, the adjacent tubes are developed horizontally In a preferred embodiment of the invention, the upper part and the lower part are achieved as modular panels that can be joined / separated individually e) This configuration of panels of the basket allows to have operations of maintenance and / or restoration faster and easier, because it is possible to intervene on the individual panels, instead of doing it on the whole structure, and possibly replace a part of the same in the case of wear or malfunction of the cooling system. According to another variant, the panels cooperate with the connecting and sliding elements that prevent damage in the case of a thermal expansion. According to a variant, the first inner wall and the second outer wall of the lower part are separated by filling material with the appropriate coefficient of heat conductivity. In one embodiment of the invention, the first internal wall consists of a layer of refractory material. This solution makes it possible to protect the adjacent tubes from both the high temperatures inside the basket, as well as the damage caused by the scrap discharge. Accordingly, it is possible to contain the dispersion of heat energy towards the external environment, thereby improving the efficiency of the previous heating process. According to a variant, the first internal wall comprises a circuit of tubes inside of which the cooling fluid circulates; the tubes of this circuit are configured separate from the adjacent tubes of the second outer wall, and their inter-axis is larger than that external tube circuit. According to another variant, between the two circuits there is a layer of refractory material. According to a further variant, the tubes of the first inner wall are coated on the front by a layer of refractory material. According to the invention, the separation spaces between the tubes of the first internal wall, encourage the particles and the powders carried by the vapors, to be deposited on the cooling tubes of the second external wall; as they cool, these particles and dusts solidify and anchor to the tubes. This causes a considerable layer to form in a single body, which insulates and protects the tubes from mechanical stresses. Moreover, the heat accumulated by this monolithic layer during the previous heating of the scrap is then released due to the irradiation during the subsequent previous heating cycle, thereby increasing the efficiency. According to a variant, at least on the tubes of the first internal wall of tubes, there are elements to accentuate the formation of the monolithic layer, which encourage the particles and powders to be deposited there. According to a variant, between the two tube circuits, there is a third circuit; the inter-axis of the tubes has an intermediate value with respect to that of the two aforementioned circuits. In a preferential mode, at least the internal tube circuit is fed in an independent manner, which allows it to be excluded in the case of a breakdown or malfunction, while the external tube circuit continues to operate. According to a variant of the invention, the tube circuits are connected to each other by means of hook elements, in order to obtain a more stable and solid structural whole. In one embodiment of the invention, the tubes are made of a continuous structure without intermediate welds or joints, which limits the number of critical points in the structure of the basket. According to another variant, the cross section of the tubes is not circular or composite, in order to make the cooling fluid circulate only in the part of the tube exposed to the heat flow, which optimizes the heat exchange coefficient of the cooling tubes. The coefficient of heat exchange is also conditioned, according to a variant, by the regulation of the cooling fluid feed rate. In correspondence with the substantially circular bottom, the basket according to the invention includes a plurality of movable toothed restraint elements radially configured and peripherally connected to one another by means of an outer ring. The teeth consist of a box structure within which the cooling fluid flows, and, according to the invention, the outer ring functions as a collector and feeder for the cooling fluid. In accordance with a variant of the invention, the basket cover also includes a cooling system with circulating cooling fluid. According to the invention, at least the upper part and the lower part of the basket include differentiated and autonomous cooling circuits. In accordance with a preferred embodiment, each component part of the basket includes a relative and independent cooling circuit. Thanks to the autonomous circuits for circulating the cooling fluid in the different component parts of the basket, these zones can be cooled in a differentiated manner according to the temperatures to which they are exposed, or according to other needs related to the previous warm-up cycle, thus avoiding waste, and consequently, reducing the costs of system administration. The cooled basket according to the invention includes, in a convenient manner, in a position near the base, lateral extensions on which there are holes and positioning and centering bolts, to make the basket suitable for fitting correctly when when on the movable elements in movement, in order to constitute a coordinated and functional structure. With this method, it is possible to use the racks loaded with scrap ready for the previous heating in a position very close to the furnace, without having to modify the structure of the shed, and without having to use other containers or structures. Moreover, the coordinated and functional structure obtained by combining the basket according to the invention, with the movable element in motion, makes it possible to use the basket also to discharge the previously heated scrap directly in the furnace, with extremely long cycle times reduced, and with minimal heat loss. In one embodiment of the invention, the placement of the basket on the movable element causes the automatic coupling of the fluid connections to feed the different fluids from the relative sources to the different tubes or connections on the basket. According to a first embodiment of the invention, the baskets have, in a lower position, a steam inlet ring that is momentarily connected to the discharge pipe. According to a variant of the invention, in the preheated position, the cooled basket cooperates with the intake element configured on the plane below, and momentarily connecting with the bottom of the basket, by means of a connecting joint which can be moved from an admission position to a non-operative position. The connection seal conveniently includes a sealing element. According to one embodiment of the invention, the movable element for moving the basket includes an intake ring, connected to the tube for discharging the vapors, and which cooperates with the lower part of the basket and with the movable bell elements. The movable bell elements have a closed position associated with the walls of the basket, and an open position that is raised and away from the walls of the basket. According to a variant, the movable bell elements include packing elements that improve the hermetic seal against infiltration and leakage. During the discharge of the scrap in the furnace, the bell elements are configured in a closed position that cooperates with the walls of the basket, and serve to contain the vapors that come out of the oven at the top, and which extend around the bottom of the basket. Accordingly, the vapors are transported entirely into the intake ring, and discharged via the discharge tube, which prevents contamination of the environment and heat losses from inside the oven. According to a further variant, in cooperation with at least one wall of at least some of the teeth defining the bottom of the basket, there are suitable temperature monitoring elements to prevent any possible overheating, and to automatically control the steps. According to another variant, the basket according to the invention is equipped with at least one duct for supplying oxygen, which has the function of generating reactions after the combustion of the vapors inside the basket and around the scrap, raising the same time the temperature. According to still another variant, the covering element and / or the side walls of the basket are equipped with burners to achieve a subsequent combustion of the vapors transported inside the basket during the previous heating step. In accordance with the invention, from the moment the basket is loaded with scrap, and constitutes a coordinated and functional structure with the movable element of movement, until the moment it is emptied and replaced, the different steps and operations related to the administration of the basket they are automated, and are managed and controlled by a computer element.

ILLUSTRATION OF THE DRAWINGS The attached Figures are given as a non-restrictive example, and show some preferred embodiments of the invention as follows: Figure 1 shows a diagram of a possible application of the cooled basket according to the invention, in cooperation with a electric arc furnace. Figure 2 shows a section along the cooled basin according to the invention, from a first point of view.

Figure 3 shows a section along the cooled basin according to the invention, from a second point of view. Figure 4 shows a cross section of the cooled basket according to the invention. Figure 5 shows a detail of a cross section of the side wall of the cooled basket according to the invention. Figure 6 shows detail A of Figure 4. Figure 7 shows detail B of Figure 4. Figure 8 shows detail C of Figure 3. Figure 9 shows a section of a detail of the bottom of the basket cooled according to the invention. Figure 10 shows a section from E to E of Figure 9. Figure 11 shows, in diagram form, the cooled basket according to the invention, during the discharge of the scrap in the furnace. Figure 12 shows, in diagram form, the detail of the quick coupling system between the cooled basket and the movable element in motion. Figure 13 shows, in diagram form, a variant of Figure 1. Figure 14 shows a variant of Figure 11. Figure 15 shows a section of a variant of the sealing system between the valves and the body of the basket. Figure 16 shows the section from D to D of Figure 15. Figure 17 is a partial view of a cross section of the lower part of the cooled basket according to a variant of the invention. Figure 18a shows a variant of Figure 17. Figure 18b shows the section from E to E of Figure 18a. Figure 19 shows a variant of Figures 17 18a. Figures 20 and 21 show the possible shapes of configuration of the anchoring elements for the tubes of Figures 17 and 18a.

DESCRIPTION OF THE DRAWINGS The cooled basket 10 according to the invention is shown in Figure 1, associated with moving movable elements, which include a truck 12 to constitute a coordinated and functional structure 44 which cooperates with an electric arc furnace 11. In this case, the movable trolley 12 is suitable to perform forward and backward movements, coupling with the movement of the roof 13 of the oven 11.

In relation to the fourth hole 14 of the oven 10, there is a tube 15 that transports the vapors leaving the oven 11 towards the interior of the cooled basket 10, which is loaded with scrap metal. __ In this case, the vapors are transported from above through an opening on the covering system 16, which may be temporarily associated with the cooled basket 10. The covering system 16 cooperates with a suitable support and connection base 61, which is present on the upper part of the cooled basket 10, in includes the appropriate sealing element. -The vapors are put in and discharged, in the case shown in Figure 1, by means of a ring 17 placed in cooperation with the lower part of the cooled basket 10, and sent to the purification and discharge by means of the tube. discharge 18. When the cooled basket 10, after having discharged the previously heated scrap, is removed from its position, to be replaced by a full basket, the vapors leaving the furnace are transported directly from the fourth hole 14 to the tube. discharge 18 by means of the branch 19. On the tube 15, the branch 19 and the tube 18, there are intercept elements that can be temporarily activated, respectively 20a, 20b, and 20c, to achieve the desired deviations in the flow of vapors according to the steps of the work cycle of the cooled basket 10, when combined with the movable trolley 12, to constitute the coordinated and functional structure 44. The cooled caisson 10 according to the invention is shown in detail with two sections along in Figures 2 and 3. In the embodiments shown, the cooled basket 10 has a substantially cylindrical shape. According to a variant that is not shown here, the cooled basket 10 is turned towards the bottom, at an angle of between Io and 5o, to assist the descent of the scrap during the unloading step. The cooled basket 10 comprises, in this case, a first upper part 10a, a second lower part 10b, and a bottom 10c. The first upper part 10a includes a support and connection base 61, in order to cooperate with the covering system 16; moreover, it includes the usual element 54 for moving the basket 10, for example, by means of a crane. The function of the first upper part 10a is to contain the scrap in the event that it becomes entangled and fixed in an incorrect manner, so that it does not completely occupy the containment area defined by the second lower part 10b. In this case, the first upper part 10a includes a wall 21 consisting of a tube bundle 122, with the adjacent vertical tubes 22 extremely close to each other, wherein the cooling fluid flows. According to a variant which is not shown here, the tube bundle 122 has the tubes 22 which are arranged in a horizontal manner. The second lower part 10b includes a wall 23 defined by a first internal wall 24 associated on the external part with a second external wall 71 consisting of a bundle of tubes 125, of the vertical tubes 25, very close to each other, where it flows the cooling fluid. According to a variant shown in Figures 18a and 18b, the tube bundle 125, which constitutes the outer wall 71, includes the tubes 25 configured on a horizontal plane. According to another variant, in the interspaces between the inner wall 24 and the outer wall 71, there is filling material 26 with the appropriate coefficient of heat conductivity, for example, silicon carbide or other suitable material. In the embodiment shown in Figures 6, 7, and 15, 16, the inner wall 24 is composed of a plurality of metallic elements configured as the arc of a circle, associated with each other by means of connection plates and sliders 27, which allow a thermal expansion at least partial of the wall, preventing any possible deformations or breaks caused by this phenomenon. The continuous inner wall 24 allows the scrap to descend without encountering obstacles, and it can also be easily restored or replaced in the case of wear. Figures 17, 18a, 18b, and 19 show variants of the inner wall 24. The embodiment shown in Figure 19 shows an inner wall 24 consisting of a layer of refractory material 72 with a high hardness and strength, of the appropriate thickness. The layer of refractory material 72 constitutes a protective barrier for the tube bundle 125, which is thus thermally insulated, and is not exposed to the high temperatures that develop inside the basket 10. Moreover, this limits the dispersion towards the external environment of the heat energy developed by the vapors, and increases the efficiency of the previous heating process. The high hardness of the refractory material layer 72 also preserves the tube bundle 125 from the mechanical stresses that result from the loading / unloading of the scrap. In the embodiment shown in Figures 17, 18a, 18b, the inner wall 24 also comprises an internal tube bundle 173 configured separate from the bundle of tubes 125 of the outer wall 71. The tubes 73 of the internal tube bundle 173 are spaced apart of each other according to a desired inter-axis, and in this case, they are substantially parallel to the tubes 25 of the tube bundle 125. The tubes 73 of the internal tube bundle 173, furthermore, are coated, in FIG. its portion that faces inside the basket 10, by a layer of refractory material 74 applied by spraying. During the preheating process, the spaced configuration of the tubes 73 encourages the deposit of particles and powders that are derived from the preheating vapors on the tubes 73. The particles solidify and amalgamate with each other, and form a block monolithic 75, which incorporates substantially. the internal bundle of tubes 173. The monolithic block 75 acts as a thermally insulating barrier, and preserves the bundles of tubes-125 and 173 of the damaging effects of the high temperatures inside the basket 10, and any possible impacts of the scrap 11. Moreover, it limits the dispersions of heat energy to the external environment to a minimum, and actually accumulates part of this energy , detaching during the course of the subsequent previous warm-up cycle. According to a variant shown in Figures 20 and 21, the tubes 25 and / or the tubes 73 include anchoring elements 76 on the external surface facing the interior of the basket 10, which are suitable for encouraging the deposit and the accumulation of particles and dusts, and consequently, the formation of the monolithic block 75. In Figure 20, the anchoring elements 76 consist of segmented ridges 77, in this case distributed in an alternating manner; in Figure 21 the anchoring elements 76 consist of longitudinal ribs 78, in this case in the form of an arch. According to a variant that is not shown here, the inner wall 24 comprises a third bundle of tubes configured in an intermediate position between the bundles of tubes 125 and 173; The third bundle of tubes consists of cooling tubes that are spaced apart by an intermediate inter-axis between those of the cooling tubes 25 and 73. The internal bundle of tubes 173 is conveniently fed in an independent manner from the external bundle of tubes 125 and The third bundle of tubes when included. This allows it to be excluded in the case of breaks or malfunctions, and therefore, it is possible to maintain the cooling effect of the basket 10 by means of the external tube bundle 125 only. According to a variant that is not shown here, the tubes 25 and / or 73, and / or the tubes of the possible third tube bundle, are not of a circular cross section; for example, they are oval, or of a composite nature, to limit the passage of the cooling fluid only to the portion of the tubes that faces the interior of the basin 10. According to a variant, the tube circuits are structurally connected with each other by means of suitable hook elements. In correspondence with the separation area between the first upper part 10a and the second lower part 10b of the cooled basket 10, in this case there is an annular conduit 55 equipped with a plurality of nozzles 28 for introducing oxygen into the basket 10, and around the scrap, in order to activate the post-combustion reactions of the vapors passing through the basket 10, inside the basket 10 itself. The post-combustion reactions, apart from raising the temperature of the vapors, also make it possible to obtain an efficient purification of the vapors. According to a further variant, shown as an example only in Figure 13, the cooled basket 10 is equipped, at its upper part, for example in the space immediately below the covering system 16, with a plurality of burners 66. In in this case, the wall 21 of the upper part 10a and / or the walls 24, 71 of the second lower part 10b of the cooled basket 10, are configured as panels 29, each covering a defined arc of a circle of the peripheral portion. relative of the cooled basket 10. With this solution, it is possible to perform a quick maintenance. Between the panels 29, there are also thermal expansion joints 80 (Figure 18a, 19) which, when this phenomenon occurs, prevent breakage or damage to the panels 29. Each of the panels 29 comprises its own inlet 30a and its own outlet 30b for the cooling fluid, respectively connected with the relative units of supply and discharge for the cooling fluid. Figure 8 shows in detail a system for feeding / discharging the cooling fluid. The Figure shows the elements 31a connecting the tubes 22 of a panel 29 of the first upper part 10a, and the elements 31b connecting the tubes 25 of a panel 29 on the second lower part 10b, with the relative areas for feeding 32a and download 32b the cooling fluid. According to the invention, at least the upper part 10a and the lower part 10b include autonomous and differentiated circuits for feeding and discharging the cooling fluid In a preferred embodiment of the invention, the covering system 16 also includes a circuit of cooling with circulating fluid According to one embodiment, the covering system 16 is of a composition identical to the structure of the second lower part 10b of the basket 10, and can be made with an internal wall consisting of a layer of material refractory, or alternatively, with an internal wall comprising an internal bundle of tubes The bundle tubes of the covering system 16 can be configured in a radial or horizontal manner In this case, the bottom 10c of the cooled basin consists of temporarily open elements, which comprise a plurality of teeth 33 radially configured, and spaced from one another. Each tooth 33 is defined by a box structure inside which the cooling fluid is flowed along a desired path. In a preferred embodiment of the invention, the basket 10 includes cooling circuits that are autonomous for each component part thereof (cover 16, upper part 10a, lower part 10b, bottom 10c). In this way, the cooling process can be differentiated according to the specific requirements and operating conditions. In this case, the cooling fluid is fed through a peripheral ring 34 which acts as a distributor for the fluid. Each tooth 33 includes within a separation and transport plate 35, as each tooth 33 is connected with the preceding and following tooth 33 (Figure 10) through the peripheral ring 34. Associated with the teeth 33, there is a sealing ring and reinforcement 56. When the cooled loaded basket 10 is associated with the movable trolley 12 to constitute the coordinated and functional structure 44, and is in the position to preheat the scrap, the sealing and reinforcing ring 56 cooperates with a connecting ring 57 The connecting ring 57, by means of the appropriate movement element 58, can be temporarily displaced along the underlying intake pipe 59, to create the desired seal for the admission of the vapors. The bottom 10c of the cooled basin 10 is structured in two portions, respectively 110c and 210c, which can be moved from a first closed position, shown by a continuous line in Figure 2, to a second open position, shown by a line of dotted in Figure 2. In the second open position, when the cooled basket 10 is placed by the movable cart 12 above the oven mouth 10, the teeth 33 open and discharge the scrap contained in the basket 10, inside the oven 11. The opening and closing of the bottom 10 are obtained, in this case, by means of the activation of the appropriate dynamic oil actuators 36, which are associated with the respective portions 110c and 210c, in correspondence with the respective limiting point 37. Each portion 110c and 210c rotates about relative hinge point 38, and is opened for the purpose of unloading scrap. ~ The outer wall 40 of each portion 110c, 210c of the bottom 10c, includes sealing elements 39 which cooperate, in the relative closed position, with the external wall 71 of the tubes 25 of the lower part 10b of the cooled basket 10. The Figures 15 and 16 show in detail a variant of the sealing system between the movable portions 110c, 210c and the body of the basket 10, in such a way that no air enters the basket 10, and / or no vapors during the heating step. previous. Each portion 110c, 210c includes an external wall 40 associated on the inside with a sealing layer 67 configured adjacent a stop ring 79 configured outside the bottom of the outer wall 71 of the body of the basket 10. In correspondence with the area of reciprocal connection in the closed position, a movable portion 110c includes an outwardly turned receptacle member 68, and the other movable portion 210c includes, at the front, a male insert segment 69 equipped with a front sealing element 707. In this case, on top of at least one tooth 33, there is a temperature monitoring element 41, for example of the thermocouple type. In this case, in cooperation with the bottom 10b of the cooled basket 10, there are lateral extensions 42 which serve to place the basket 10 correctly on the movable trolley 12, and automatically achieve the desired electrical, hydraulic, and oxygen connections. At least the fluid connections of the cooling lines 46, and the power connections 47 of the dynamic oil actuators 36, converge on the lateral extensions 42 (Figure 12). There are centering holes 43 on the lateral extensions 42, which cooperate with the coupling bolts 45 of the movable trolley 12. The positioning of the cooled caisson 10 on the movable trolley 12 causes rapid automatic coupling of the fluid connections 46 and 47 with the relative power connections 48 connected to the respective fluid sources. In this case, on the frame of the movable trolley 12, there is an intake ring 49 which, during the discharge of the scrap in the furnace 11, allows the vapors to be directed towards a discharge pipe 50, which is connected to the purification and discharge plant. The intake ring 49 cooperates with the bell elements 51, at least partially surrounding the intake ring 49, and solidly associated therewith in correspondence with the connection joint 52. The bell elements 51, at least during the discharge of the scrap in the furnace closes the walls of the cooled basket 10, substantially defining an intake chamber 60 that closes to the external environment. The seal of the intake chamber 60 is ensured by the presence of sealing elements 53, which cooperate with the walls of the cooled basket 10 at least in the closed position of the bell elements 51. The inclusion of the bell elements 51, together with the admission of the vapors achieved by the intake ring 49, prevents the vapors from escaping into the external environment, and minimizes heat loss from inside the oven 11. The bell elements 51 can be rotated around the connecting link 52 by means of actuators not shown here, to assume an open position, as indicated by a dotted line in Figure 11. The open position is taken by the bell elements 51 at least when the loaded basket chilled is installed, and when the empty cooled basket 10 is removed by the relative movable carriage 12, to move the basket 10. According to the variant shown in Figure 14, the bell elements 151 are stationary, and include a first conduit of intake 49 configured just above the mouth of the furnace 11, and a second intake duct 149 connected with a conduit 64 which is connected to the main discharge pipe 50. The dotted lines indicate the channeling of the vapors and gases from the mouth of the furnace 11 to the intake ducts 49, 149, and from there to the discharge ducts 64 and 50. This configuration, which gives larger intake ducts 49, 149, ensures an extremely high intake efficiency, which can even make it possible eliminate secondary admission on the roof of the shed, and therefore, achieve very high savings.

In accordance with the modality shown in the Figure The intake duct 49 includes holes 65 on the underside, which allow the vapors and gases to be introduced and channeled, which tend to extend below the movable trolley 12. Above the second intake duct 149, there is a closure system movable seal 63, which causes the formation of a closed intake chamber 60 on the circumference of the basket 10. The movable sealed closing system 63 can be brought to an open position, for example, to move the basket 10 from the movable cart 12. Figure 13 shows a possible variant of Figure 1 according to the embodiment of Figure 9. In this embodiment, the vapors of the previous heating are discharged from the bottom of the basket 10, and are sent to a collection chamber and sedimentation 62 located below the basin 10, from where they are then discharged by means of the tube 118. The movable trolley 12 includes, in this case, two components 112 and 212: the component 112 of the movable trolley 12 serves to position and move the chilled basket 10, while the component 212 serves to position and move the roof 13 of the oven 11. Normally, the two components 112 and 212 are connected from a mechanically or electrically, but, during maintenance, or for special operations, they can operate separately.

Claims (29)

1. A cooled basket for steel plants used in loading / unloading scrap operations inside an arc furnace (11) and for preheating the same scrap by means of the vapors coming from the fourth hole (14) of the furnace, including the basket a containment body of a substantially cylindrical shape, this containment body comprising a side wall, a cooled bottom equipped with temporarily toothed lower closing elements, and lateral extensions for moving and placing the basket, the basket being characterized because the containment body comprises a first upper part (10a), a second cooled lower part (10b), and a cooled, openable bottom (10c), the second lower part (10b) including an inner wall (24) and an outer wall (71), the outer wall consisting of (71) in adjacent tubes (25) through which the cooling fluid flows, this second lower part defining (10b) an internal volume that is substantially coupled with the volume of the scrap amount to be discharged in the arc furnace (11) for each unloading operation, the first top part (10a) including a wall (21) which consists of adjacent tubes (22) through which the cooling fluid flows, this first upper part (10a) acting as an intermediate storage, to temporarily increase the capacity of the basket.

2. The basket as in claim 1, characterized in that the first upper part (10a) is associated with its own cooling element, differentiated and autonomous with respect to the cooling element of the second lower part (10b).

3. The basket as in claim 1 or 2, characterized in that the toothed closure elements (33) of the cooled bottom (10c) are associated with their own autonomous cooling elements.

4. The basket as in claim 3, characterized in that each tooth _ (33) is defined by a box structure within which the cooling fluid is flowed.

The basket as in claim 1, characterized in that the interspaces between the inner wall (24) and the adjacent tubes (25) of the external wall (71) of the second lower part (10b) include filling material (26) .

6. The basket as in claim 1, characterized in that the tubes (25) are arranged vertically.

7. The basket as in claim 1, characterized in that the tubes (25) are arranged horizontally.

8. The basket as in claim 1, characterized in that the inner wall (24) is made of metal foil.

9. The basket as in claim 1, characterized in that the internal wall (24) consists of a layer of refractory material (72).

10. The basket as in claim 1, characterized in that the internal wall (24) comprises an internal tube bundle (173), with tubes (73), wherein the cooling fluid circulates, the tubes (73) having an inter - Axis greater than that of the tubes (25) of the outer wall (71), and spaced apart from each other.

The basket as in claim 10, characterized in that the tubes (73) of the internal wall ~ (24), and / or the tubes (25) of the external wall (71) are coated on the front with a layer of refractory material (72, 74).

The basket as in claims 10 or 11, characterized in that the tubes (73) of the internal wall (24) are fed independently of the tubes (25) of the external wall (71).

The basket as in claims 10 or 11, characterized in that at least the tubes (73) of the inner wall (24) include anchoring elements (76), (77), (78), for anchoring particles and dust.

14. The basket as in claim 1, characterized in that the adjacent tubes (22) of the wall (21) of the first top part (10a) are arranged vertically.

15. The basket as in claim 1, characterized in that the adjacent tubes (22) of the wall (21) of the first upper part (10a) are arranged horizontally.

16. The basket as in any of the preceding claims, characterized in that the tubes (22) of the first upper part (10a) and / or the tubes (25, 73) of the second lower part (10b), are of the type without unions and / or welds.

The basket as in any of the preceding claims, characterized in that the tubes (22) of the first upper part (10a), and / or the tubes (25, 73) of the second lower part (10b) are not one circular section.

The basket as in any of the previous claims, characterized in that the adjacent tubes (22) of the first upper part (10a), and / or the walls (71, 24) of the second lower part (10b), are configured as replaceable panels (29).

19. The basket as in claim 18, characterized in that the panels (29) cooperate with connecting and sliding elements (27), and / or with the thermal expansion joints (80).

20. The basket as in any of the previous claims, characterized in that, in cooperation with the first upper part (10a), there is at least one conduit for supplying oxygen (55).

The basket as in any of the previous claims, characterized in that, in cooperation with the first upper part (10a), there are post-combustion burners (66).

22. The basket as in any of the previous claims, characterized in that it includes, in the first upper part (10a), a base of support and connection (61) that cooperates temporarily with a covering system (16), when the latter is in the closed position ..

23. The basket as in any of the preceding claims, characterized in that it includes, in the second lower part (10b), lateral extensions (42) including centering elements (43). ), and quick connections to the tubes (46, 47), which can be associated with a movable trolley (12), to constitute a coordinated and functional structure (44).

24. The basket as in claim 23, characterized in that it cooperates with the intake ring element (49), and with the bell elements (51) on the movable trolley (12), at least during the unloading of the scrap into the oven (11).

25. The basket as in claim 23, characterized in that, when associated with the movable trolley (12) to constitute a coordinated and functional structure (44) it has a first position for pre-heating the scrap, with the covering system (16) in a closed position, and with the roof (13) of the furnace (11) in a working position, and a second position for unloading the scrap, with the roof (13) of the furnace (11) removed, leaving the basket (10) aligned with the furnace (11), the bell elements (51, 151) constituting a closed intake chamber (60) above the mouth of the furnace (11), and the intake ring (49) connected with an intake system steam.

26. The basket as in claim 24, characterized in that the bell elements (51) can be moved from a first closed position around the basket cooled in (10) to a second open position.

27. The basket as in claim 25, characterized in that the bell elements (151) are stationary, cooperate with the sealing elements (63) that can be temporarily closed on the cooled basket (10) and define a second intake ring ( 149) above the intake ring (49).

28. The basket as in any of the previous claims, characterized in that it is widened towards the bottom.

29. The basket as in any of the previous claims, characterized in that it includes a covering system (16) with a cooling circuit, where the fluid circulates.