Weighing device, automated system for controlling the feeding of a charge material into a furnace, device using such a system and

Abstract

The invention relates to a weighing device for charge fed into an electric arc furnace, comprising a plurality of supports, each support comprising an upper plate, a lower plate and a weighing element in contact with and arranged between the two plates, where at least one of the weighing elements is a column-type weighing sensor, and wherein each support comprises two connection elements perpendicular to each other, each connection element having a tie bar connected to at least one upper terminal for connection to the upper plate and at least one lower terminal for connection to the lower plate.

Description

Technical Field

[0001] Embodiments described herein relate to a weighing device, an automated system for controlling the feeding of charge material into a melting furnace using the weighing device, an apparatus using the system, and a method for controlling the feeding of charge material into a melting furnace using the apparatus.

[0002] The weighing device object of the invention is used to measure the weight of a furnace, the weight of its contents and the weight of each element mounted in or on said furnace, in particular but not exclusively during progressive feeding of charge in a melting furnace using a continuous feed system.

[0003] A control system is used to control operating parameters in a melting furnace of a metal charge using information and signals from weighing devices associated with the furnace itself.

[0004] In a preferred but non-limiting manner, the device, control system, equipment and method can be applied in the steel industry for the production of steel or other metals, or for the production of glass materials, for example, in electric arc furnaces, molten metal ladles, submerged arc furnaces, melting or refining furnaces, induction melting furnaces or induction heating furnaces, etc. Background Art

[0005] An apparatus for converting and melting metallic materials is known, comprising an electric arc furnace arranged to cooperate with a system for feeding the charge, which system may be of the continuous type (for example with a conveyor belt) or of the discontinuous type (for example with baskets). The furnace has at least one container or casing and a covering roof. Electrodes are introduced through holes in the roof to start and maintain the melting of the charge.

[0006] It is also known to use weighing systems of direct or indirect type, the latter for example based on the measurement of the level of a liquid bath, to obtain information on operating parameters that are then used to control the operation of the furnace.

[0007] Systems are known in which the furnace is weighed regularly to detect the amount of steel present in the furnace, in which the temperature of the liquid bath is also measured substantially continuously, and in which the rate of discharge of charge into the furnace is detected by weighing and regulated so that the temperature of the developing liquid bath is always kept near a desired and predetermined value.

[0008] Also known are systems and methods which use measurements of the furnace and the weight of charge introduced into the furnace to determine the rate at which charge is fed into the furnace.

[0009] Furthermore, systems are known in which the device for weighing the furnace also serves as a support for the furnace or for a structure supporting the furnace.

[0010] A disadvantage of the prior art is that such weighing devices must be able to withstand considerable weight and therefore considerable mechanical stress.

[0011] Another disadvantage of the prior art is that, due to weight and mechanical stress, the weighing device may provide data with unsatisfactory accuracy.

[0012] Document JPH1032575 describes a weighing device with a weighing sensor, which can be used in food plants, water treatment plants or tanks.

[0013] It is therefore an object of the present invention to provide an optimized device, system, apparatus and method to improve the weight measurements obtained and make them more reliable and accurate.

[0014] Another object of the invention is to make the control of charging the furnace more efficient, optimizing the energy contribution supplied inside the furnace.

[0015] Another object of the present invention is to improve the control of the level of molten metal in the furnace.

[0016] Another object of the present invention is to improve the quality of the bath of molten metal in the furnace.

[0017] Another object of the present invention is to improve the mechanical stability of the furnace itself during all steps of the melting cycle.

[0018] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. Summary of the invention

[0019] The invention is set forth and characterized in the independent claim. Other novel features of the invention are set forth in the dependent claims.

[0020] The invention relates to a weighing device, a control system, a device and a method for controlling a melting process in an electric furnace.

[0021] According to one feature of the invention, a weighing device for a charge fed into a melting furnace comprises a plurality of supports, each support comprising an upper plate, a lower plate and a weighing element, the upper plate and the lower plate being arranged parallel to each other during use, the weighing element being in contact with the two plates and being arranged between the two plates.

[0022] At least one of the weighing elements is a column weighing sensor, and each support member includes two connecting elements, which are perpendicular to each other and located on a plane parallel to the plane defined by the upper plate and the lower plate, and each connecting element has a tie rod, which is connected to at least one upper terminal and at least one lower terminal, the upper terminal is used to connect to the upper plate, and the lower terminal is used to connect to the lower plate.

[0023] A preferred embodiment of the present invention provides that the upper plate is configured to contact the furnace and the lower plate is configured to contact and be attached to a horizontal pivoting platform supporting the furnace.

[0024] According to the invention, the upper plate is located in sliding contact with respect to the side or lower wall of the furnace, for example with respect to the lower wall of the furnace housing. Similarly, the lower plate is attached by welding or fixed in any other way to the upper surface of the horizontal pivoting platform on which the furnace rests.

[0025] The number of the supports is at least three, and even more advantageously four, and they are distributed around the periphery of the bottom of the housing.

[0026] The weighing element is arranged in such a way that it is compressed with each change in weight of the furnace, for example from receiving a quantity of charge (in the form of scrap metal, coal, sponge iron or a mixture thereof), or from tapping of molten material.

[0027] The weighing cell according to the invention is able to register weight variation values ​​with remarkable accuracy and sensitivity due to its construction and its stable positioning by the presence of a connecting element which brings the supporting element into contact with the furnace on one side and with the horizontal pivoting platform on the other side.

[0028] Each weighing element acts as a rod which is compressed based on the weight change, thus determining the relative movement between the furnace and the horizontal pivot support platform.

[0029] The presence of a plurality of supports suitably (advantageously evenly and / or symmetrically) distributed on the periphery of the base of the furnace allows obtaining a corresponding number of values ​​that can be compared with one another to obtain information as well as information about the weight of the material unloaded and about its distribution inside the furnace. In this way, the operation of the unloading device can also be managed to prevent local accumulations and / or non-optimal distribution of the charge unloaded inside the furnace.

[0030] One embodiment of the invention provides that the processing unit receives information about a plurality of weight values ​​detected by the individual weighing elements, processes them and accordingly regulates the unloading speed of the charge inside the furnace, in particular in the case of continuous unloading by means of a belt or the like.

[0031] Furthermore, thanks to the information about local variations in weight, the risk of the material unloaded into the furnace striking and damaging structures and auxiliary elements at least partially present inside the furnace, such as electrodes, burners, lances, tuyere or others, can also be reduced.

[0032] These auxiliary elements have in particular the function of supplying to the furnace additional energy, for example of chemical type, in addition to the electrical energy supplied by the electrodes.

[0033] According to another characteristic of the invention, the weighing element thus constructed is capable of adapting itself in the event of misalignments of the base, the supports and / or the resting platform of the furnace.

[0034] Leveling of the furnace can be achieved by using tie rods associated with electric adjustment devices controlled by an automated control system.

[0035] According to another example of the invention, each support comprises a cooling housing to control the temperature of the associated weighing element.

[0036] According to another example of the invention, the cooling shell is a hollow cylindrical shell which at least partially surrounds the central rod, in which a cooling liquid circulates, the cooling liquid being introduced into the cooling shell through an inlet nozzle and being led out of the cooling shell through an outlet nozzle.

[0037] According to yet another example of the invention, at least one column weighing element comprises a central rod configured to support at least a portion of the weight of the furnace, the weight of its contents and the weight of each element mounted in or on the furnace.

[0038] According to another example of the present invention, the central rod includes at least two deformation sensors.

[0039] According to another example of the present invention, the center rod is attached to the lower plate in a detachable or non-detachable manner.

[0040] Another embodiment of the present invention provides an automated system for controlling the feeding of charge into an electric arc furnace, the system comprising: a weighing device of the above type, wherein a support is inserted between the furnace and a horizontal pivoting platform; and a processing unit, the processing unit being configured to control the amount of charge fed into the furnace according to the value of energy supplied to the molten bath based on information about the weight generated by the weighing device.

[0041] In one example of the invention, the value of the energy supplied to the bath corresponds to the value of the electrical power supplied to the electrodes and the value of the chemical energy supplied by the auxiliary device during the melting sequence.

[0042] In this way, the increment of charge introduced into the furnace is always directly related to the total amount of energy delivered to the furnace.

[0043] Another aspect of the invention provides an apparatus comprising an electric arc furnace including an automated system for controlling the feeding of charge into the furnace as described above.

[0044] Another aspect of the invention provides a method for controlling the feeding of charge into an electric arc furnace during a melting sequence, the method being performed by an automated control system. The method comprises the steps of determining, by means of weighing elements, at different moments in time, a plurality of weight values ​​of the furnace, its contents and each element mounted in or on the furnace; a step of obtaining, by means of a processing unit, a value of the total energy supplied to the bath; a step of controlling, by means of the processing unit, the amount of charge to be introduced into the furnace by means of a conveying element for the charge, based on the total energy value and the weight value.

[0045] In one example of the invention, the method comprises the step of obtaining a total energy value based on the value of the electric power supplied to the electrode and the value of the chemical energy supplied by the auxiliary device.

[0046] In another example of the invention, the method comprises the step of regulating, by means of a processing unit, the speed of the conveying device of the charge based on a weight value given by the weighing device and based on a value of the total energy conveyed in the furnace.

[0047] The advantage of such a device, system, apparatus and method is that, due to the structure and construction of the weighing device, the operation of controlling the feed of the electric arc furnace is automatically performed on the basis of extremely precise weight values. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] These and other aspects, features and advantages of the invention will become apparent from the following description of some embodiments given as non-limiting examples with reference to the accompanying drawings, in which:

[0049] - Figure 1 The figure shows a device for controlling the feeding of an electric arc furnace, the device comprising said furnace, a platform for supporting the furnace and a system for measuring the weight of the furnace and for feeding the charge;

[0050] - Figure 2 The figure shows a projection view of a support for an electric arc furnace;

[0051] - Figure 3 The figure shows a partially exploded three-dimensional view of a support for an electric arc furnace;

[0052] - Figure 4 The figure shows a cross section of a weighing element included in a support of an electric arc furnace;

[0053] - Figure 5 The figure shows a simplified diagram of a process unit of a plant comprising an electric arc furnace.

[0054] To facilitate understanding, the same reference numerals have been used, where possible, to identify the same common elements in the drawings. It should be understood that elements and features of one embodiment may be conveniently combined or incorporated into other embodiments without further clarification. DETAILED DESCRIPTION

[0055] We will now refer in detail, by way of non-limiting illustration, to possible embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The phraseology and terminology used herein is also for the purpose of providing non-limiting examples.

[0056] Reference Figure 1 , the embodiments described herein relate to an apparatus 10 comprising a furnace 100, in this particular case of the electric arc type, comprising a housing 110 for containing a charge 210 to be melted and / or a charge of molten metal, a covering roof 120, an inlet channel 130 through which the charge 210 is inserted into the furnace 100, and a slag channel 140 allowing the slag to be discharged at the end of the melting process. The furnace also generally comprises a tapping aperture, known as an EBT, at the bottom of the housing 110, which is not shown in the figures.

[0057] The furnace 100 is also provided with one or more electrodes 150, which are inserted into the furnace 100 through the cover roof 120 and are configured to deliver energy to melt the charge 210 in the shell 110 (furnace 100) and obtain a molten metal charge or bath 200 by generating an arc between the plurality of electrodes 150 when the furnace is powered by alternating current or by generating an arc with the bottom of the shell when the furnace is powered by direct current.

[0058] One or more electrodes 150 are detachably mounted on the furnace 100, and can be inserted into or removed from the furnace 100 according to process requirements and / or to prevent damage to the one or more electrodes 150 or the furnace 100. The one or more electrodes 150 are connected to a power supply system, which is not shown in the drawings. The one or more electrodes 150 and the power supply system can be electrically connected or disconnected based on the processing steps, or based on safety considerations during the steps of loading the charge 210, unloading the molten metal charge, deslagging or slagging.

[0059] The power supplied to the electrodes 150 may be varied over time, starting from a minimum power, to reach an operating power by increasing the power supplied to more than one electrode 150 depending on the amount of charge material 210 and / or molten bath 200 present in the furnace 100 .

[0060] The furnace 100 is also provided with auxiliary elements, such as burners, oxygen lances, pulverized coal injectors and the like, not shown, capable of facilitating the melting process in the furnace 100 by supplying additional energy, mainly originating from chemical type reactions.

[0061] The apparatus 10 further comprises a horizontal pivoting platform 160 , a moving element 180 allowing the horizontal pivoting platform 160 to be tilted, and a weighing system or device comprising a plurality of supports 170 inserted between the horizontal pivoting platform 160 and the furnace 100 .

[0062] exist Figure 1 In the embodiment, the moving element 180 is shown as a roller inserted between the horizontal pivot platform 160 and the base platform 190 resting on the ground. It will be understood by those skilled in the art that the moving element 180 can be composed of any element that allows the horizontal pivot platform 160 to tilt at a certain angle relative to the horizontal direction, and they are not limited to Figure 1 The roller shown in .

[0063] The furnace 100 is mechanically connected to the horizontal pivoting platform 160 by means of supports 170 , whereby each tilting of the horizontal pivoting platform 160 causes a tilting of the furnace 100 .

[0064] During operation of the furnace, that is to say during a melting sequence, the horizontally pivoting platform 160 and therefore the furnace 100 are oscillated by the movement device 180 at an angle generally comprised between −5 degrees and +5 degrees relative to the horizontal.

[0065] Optionally, during the deslagging step, the movement device 180 is configured to tilt the horizontal pivoting platform 160 and therefore the furnace 100 relative to the horizontal by an angle typically comprised between -1 and -15 degrees.

[0066] Optionally, during the unloading step, the movement device 180 is configured to tilt the horizontal pivoting platform 160 and therefore the furnace 100 relative to the horizontal by an angle typically comprised between +5 and +20 degrees.

[0067] If the loading of charge 210 is a discontinuous process, such as when charge 210 is unloaded into furnace 100 via more than one basket, roof 120 is at least partially opened or removed, and electrode 150 is removed and disconnected from the power supply.

[0068] The loading of the charge material 210 may also be performed in a continuous process by a conveying device 135 such as a conveyor belt positioned, for example, in a preheating tunnel, the conveying device 135 being configured to continuously unload the charge material 210 into the furnace 100 .

[0069] The continuous and discontinuous type processes for loading the charge 210 into the furnace 100 may also be combined sequentially or in parallel. In particular, based on considerations related to the temperature inside the furnace 100 or the power supplied to the electrode 150, or based on considerations of the total energy supplied to the charge 210 or the molten bath 200 present in the furnace 100, the discontinuous loading type process may be used to start the melting sequence, and may be replaced by the continuous loading process during the melting sequence.

[0070] In the case of such a continuous loading process, the charge material 210 is continuously unloaded into the furnace 100 even during the melting sequence and can only be interrupted during the deslagging step or during the tapping of the molten material.

[0071] In the present invention, the furnace 100 is placed on the horizontal pivot platform 160 by a weighing device, which includes a plurality of supports 170 arranged along the lower circumference of the furnace 100 or the housing 110, and these supports 170 are inserted between the furnace 100 and the horizontal pivot platform 160. The furnace 100 is basically placed on the supports 170 and its weight is unloaded on the horizontal pivot platform 160 only by the supports 170. Preferably, the number of supports 170 is at least three. Those skilled in the art will understand that the number of supports is not limited to Figure 1 The number shown in the figure is not limited to three, and the invention may include more than three supports without compromising the field of protection.

[0072] Each support 170 comprises one or more weighing elements 171 and two connecting elements 173 which allow the furnace 100 to be mechanically connected to the horizontal pivoting platform 160. At least one of the weighing elements 171 is a column load cell comprising a central rod 171a which supports the weight of the furnace, its contents and each element mounted in or on the furnace 100.

[0073] The central rod 171a comprises at least two deformation sensors (not shown in the figures) which allow the detection of deformations of the central rod 171a caused by compression along the vertical axis or by components along the vertical axis, in other words by changes in weight acting on the rod 171a.

[0074] Optionally, the temperature of each of the one or more weighing elements 171 is controlled by a cooling shell 177 .

[0075] The two connecting elements 173 are perpendicular to each other so as to constrain the movement of the furnace 100 and the horizontal pivoting platform 160 in two axes.

[0076] exist Figure 2 and Figure 3In the example of the present invention shown in , each support 170 includes a weighing element 171 inserted between an upper plate 172a and a lower plate 172b. The upper plate 172a of the support 170 is configured to contact the lower surface 100a of the furnace 100, while the lower plate 172b is configured to contact the upper surface 160a of the horizontal pivot platform 160.

[0077] Those skilled in the art will appreciate that the upper plate 172a of the support 170 may also contact the side 100b of the furnace 100, or similarly contact the side 100b of the housing 110.

[0078] The attachment of the lower plate 172b of the support 170 to the upper surface 160a of the horizontal pivot platform 160 may be achieved by an attachment device, or it may be non-detachable, such as by welding.

[0079] exist Figure 1 , Figure 2 and Figure 3 , the upper plate 172a and the lower plate 172b are shown as flat plates. The upper plate 172a and the lower plate 172b are arranged to be substantially parallel to each other during use. Those skilled in the art will appreciate that the upper plate 172a and the lower plate 172b can have any shape, such as to accommodate the shape of the lower surface 100a and / or the side 100b of the furnace 100 and the shape of the upper surface 160a of the platform 160, respectively.

[0080] In the case of a non-planar shape of the plates 172a, 172b, in any case the parallel state is at least partially maintained during use due to their shape.

[0081] The weighing element 171 of the support 170 is contained between an upper plate 172a and a lower plate 172b, which are connected to each other by two connecting elements 173. The two connecting elements 173 are arranged perpendicular to each other and are located on a plane substantially parallel to the plane defined by the upper plate 172a and the lower plate 172b. Each connecting element 173 includes a tie rod 173c, an upper terminal 173a and a lower terminal 173b located at the end of the tie rod 173c.

[0082] The upper terminal 173a is configured to be mechanically connected only to the upper plate 172a, and the lower terminal 173b is configured to be mechanically connected only to the lower plate 172b. In other words, the tie rod 173c is mechanically connected to the upper plate 172a through the upper terminal 173a, and is mechanically connected to the lower plate 172b through the lower terminal 173b.

[0083] The mechanical connection between the tie rod 173c and the upper terminal 173a and the lower terminal 173b is ensured by a connecting element 173d such as a joint, a hinge, a pin, etc. Those skilled in the art will understand that any connecting element capable of mechanically connecting two mechanical elements and configured to allow relative movement between the two elements can be used as the connecting element 173d in the present invention.

[0084] The upper terminal 173a and the lower terminal 173b can be mechanically connected to the upper plate 172a and the lower plate 172b respectively by screw connection elements (not shown in the drawings). Optionally, the upper terminal 173a and the lower terminal 173b are attached to the respective plates in an undetachable manner, such as by welding.

[0085] The two connecting elements 173 are positioned perpendicular to each other so as to constrain the relative movement between the upper plate 172a and the lower plate 172b in two axes. This arrangement of the two connecting elements 173 also allows limiting the movement of the furnace 100 along the two axes so as to absorb or eliminate shear forces along the two axes.

[0086] Furthermore, the connecting element 173 can be used to align and / or level the furnace 100 relative to a predetermined position, or equivalently align and / or level the housing 110. These adjustments, alignments and / or leveling of the furnace 100 are obtained by conventional manipulation of extending or shortening the length of the tie rods 173c of the connecting element 173.

[0087] The weighing element 171 is inserted between the furnace 100 and the horizontal pivoting platform 160 and only supports, i.e. measures only the weight of the upper plate 172a, the weight of the furnace 100, the weight of the contents of the furnace 100 and the weight of each element mounted in or on the furnace 100 (e.g. the electrode 150) when these are mounted and act on the furnace 100 with their weight.

[0088] The weight of the upper plate 172a is several orders of magnitude less than the weight of the furnace 100 and any other items being weighed. It is therefore reasonable to ignore this value in any calculation involving the weight value detected by the weighing element 171.

[0089] A person skilled in the art will understand that, in the case of identical elements installed in or on the furnace 100, the difference between two weighing values ​​of the furnace 100 can give an indication of changes in the contents of the furnace, that is, whether any charge 210 has been introduced into the furnace and / or whether the molten bath 200 has been at least partially withdrawn from the furnace 100, for example by tapping.

[0090] Optionally, each of the plurality of supports 170 includes the same type of weighing element 171. In another example, at least one of the plurality of supports 170 includes a weighing element 171, which is constituted by a column-type weighing sensor, which includes a center rod 171a, which is preferably connected to the lower plate 172b in a non-detachable manner and is configured to support the weight of the furnace 100, its contents, and each element installed in or on the furnace 100.

[0091] As previously mentioned, the rod 171a comprises at least two deformation sensors, not shown in the figures, optionally perpendicular to each other, capable of measuring the deformations undergone by the rod 171a under the influence of the weight of the furnace 100, its contents and each element mounted in or on the furnace 100. Optionally, the rod 171a comprises four pairs of deformation sensors perpendicular to each other and electrically configured in such a way as to create a Wheatstone bridge.

[0092] At least two deformation sensors generate electrical signals based on the deformation caused by the load (weight) acting on the rod 171a. The electrical signals generated by the deformation sensors are sent to the processing unit 300 (only in Figure 5 310, memory 320 and communication unit 330 are connected and can communicate with each other through physical support or wireless means.

[0093] In the following, we will refer to the processing unit 300 without specifying which element performs the various functions described, which is considered common practice. In addition, the processing unit 300 is capable of controlling the power supply of the electrode 150. Alternatively, the power supply of the electrode 150 is controlled by a power supply unit (not shown in the drawings) optionally connected to the processing unit 300.

[0094] In one example of the present invention, the electrical signal is transmitted to the processing unit 300 through at least one cable 176. In another example of the present invention, the electrical signal is processed and sent to the processing unit 300 through a wireless connection. In another example of the present invention, the electrical signal generated by the deformation sensor is pre-processed by a processing unit (not shown in the drawings) installed near the weighing sensor, and the pre-processed signal is sent to the processing unit through a physical medium, cable, wire, etc. or in a wireless mode.

[0095] Optionally, the processing unit 300 receives a single signal generated by processing multiple signals from various deformation sensors. In another example, the processing unit 300 receives as many electrical signals as there are deformation sensors, which are directly generated by the deformation sensors or pre-processed.

[0096] The weighing element 171 works under compression by detecting a deformation of the rod 171a which is proportional to the load applied to the weighing element 171. In this way, the weighing element 171 allows real-time monitoring of the weight of the furnace 100, the weight of its contents and the weight of each element present or mounted in or on the furnace 100.

[0097] The support 170 is mounted near the furnace 100 and, for this reason, is subjected to the high temperatures generated by the melting of the charge 210 or by the molten bath 200. In order to prevent the deformation sensor present on the rod 171a from malfunctioning or from any effects caused by the high temperatures, the weighing element 171 is provided with a cooling system comprising a cooling shell 177 at least partially surrounding the rod 171a.

[0098] The cooling shell 177 is a generally hollow cylindrical housing or a portion thereof. A cooling liquid 177c (optionally water) is circulated within the cooling shell 177, thereby allowing the temperature of the rod 171a to be controlled. The cooling liquid is introduced into the cooling shell through an inlet nozzle 177a and is led out of the cooling shell 177 through an outlet nozzle 177b. The inlet nozzle 177a and the outlet nozzle 177b are formed on the outer surface of the cooling shell 177, and each allows connection with a conduit (not shown in the drawings) that allows the entry and exit of the cooling liquid, respectively.

[0099] The cooling liquid 177c drawn out from the cooling shell 177 through the outlet nozzle 177b is cooled by a cooling unit not shown in the figure and reintroduced into the cooling shell 177 at an appropriate temperature through the inlet nozzle 177a. Optionally, each cooling shell 177 is connected to a cooling unit. Alternatively, the cooling shells 177 of all weighing elements 171 are connected to a single cooling unit.

[0100] Controlling the temperature of the weighing element 171 allows eliminating or minimizing the effects of temperature on the measurement of the weight of the furnace 100 , the weight of its contents and the weight of each element mounted in or on the furnace 100 .

[0101] The processing unit 300 uses data related to the weight of the furnace 100, the weight of its contents, and the weight of each element installed thereon or therein to determine the amount of charge 210 to be introduced into the furnace 100. The charge 210 is transported and introduced into the furnace by a conveying device 135, which transports the charge 210 from the outside of the furnace 100 to the inlet channel 130 and then to the inside of the furnace 100. For example, the conveying device 135 can be a conveyor belt; however, those skilled in the art will understand that any moving device capable of introducing the charge 210 into the furnace 100 can be used without impairing the purpose of the present invention.

[0102] The conveyor device 135 is connected to the processing unit 300, which controls its movement based on commands pre-set by the operator or pre-recorded in the memory of the processing unit 300, and thus controls the introduction of the charge 210 into the furnace. In one example of the present invention, the processing unit 300 controls the movement of the conveyor device 135 based on data received from sensors (e.g., deformation sensors of the weighing element 171 or temperature detection sensors (not shown in the drawings) that measure the temperature value of the furnace and / or its contents) and / or based on operating parameters (e.g., the power supplied to the electrode 150).

[0103] In one example of the present invention, at least one of the following values ​​detected by a sensor not shown in the figure, such as a temperature value of the interior of the furnace 100 and / or the contents, a chemical substance detection sensor value, a pressure value, a power value supplied to the electrode 150, and a chemical energy value generated by a reaction occurring in the furnace, is used to obtain a total energy value supplied to the charge 210 or the molten bath 200 present in the furnace 100.

[0104] Optionally, the value of the total energy supplied to the charge 210 or molten bath 200 takes into account the value of the electrical power supplied to the electrode 150 and the value of the chemical energy generated by the reaction caused by the introduction of solid and gaseous substances through auxiliary elements as described above.

[0105] In another example of the present invention, the total energy value obtained from the processing unit 300 is combined with the weight value measured by at least one of the multiple weighing elements 171 and sent to the processing unit 300 to determine how to adjust the amount of charge 210 to be introduced into the furnace 100 based on the power delivered into the furnace.

[0106] In order to control the amount of charge material 210 introduced into the furnace 100 , the processing unit 300 controls the conveying device 135 to supply additional charge material 210 or to stop / slow down the introduction of charge material 210 into the furnace 100 .

[0107] Furthermore, the arrangement of at least three supports 170 along the periphery of the furnace 100 allows the identification of the weight distribution of the charge 210 inside the furnace 100. In this case, the weight values ​​detected by the weighing elements 171 of the supports 170 are processed by the processing unit 300 to determine the geometrical distribution of the weight of the contents of the furnace 100. The processing unit 300 can also determine such a geometrical distribution based on data related to the inclination of the furnace 100 relative to the horizontal position, taking into account the displacement of the contents of the furnace 100 when the furnace 100 is tilted by the horizontal pivoting platform 160.

[0108] In one example of the present invention, the processing unit 300 uses data related to the weight distribution of the charge, alone or in combination with the data described above, to determine not only the amount of charge 210 to feed the furnace 100, but also the distribution of the charge 210 and / or the molten bath 200 inside the furnace 100.

[0109] Optionally, the processing unit 300 controls the direction in which the charge material 210 is unloaded by the conveyor device 135 based on data regarding the distribution of the charge material 210 .

[0110] The use of data related to the weight distribution of the charge 210 by the processing unit 300 allows preventing non-optimal accumulation and / or distribution of the charge 210, which may affect the melting efficiency, i.e. the amount of energy used to melt the charge 210 and / or to maintain or complete the melting of the molten bath 200, as well as the time required to achieve melting of the charge 210. Furthermore, this allows preventing the charge 210 from being incorrectly positioned in the furnace 100, or from coming into contact with or colliding with delicate structures and / or elements installed in the furnace (e.g. electrodes 150, burners, lances, tuyere, etc.).

[0111] Optionally, weighing the furnace 100 and its contents and each element mounted in or on the furnace 100 is repeated periodically over time. By studying the trend of the weight values ​​measured at different moments, an indication of the amount of molten bath 200 present in the furnace can be obtained.

[0112] Assuming that the weight of the furnace 100 and the weight of each element installed in or on the furnace 100 are values ​​that do not change over time, the difference between the weight values ​​obtained from the weighing element 171 depends only on how much charge 210 has been introduced into the furnace, or how much molten bath 200 has been withdrawn from the furnace 100. This is particularly true for weighings performed at short time intervals during a period of time when the furnace 100 can be used continuously without requiring recovery or maintenance operations thereon.

[0113] Over a longer period of time, the difference between the two weighing values ​​of the furnace 100, its contents and each element installed in or on the furnace 100 can provide data on the wear of the furnace 100, in particular on the wear of the inner walls of the furnace 100, or similarly on the presence of accumulated slag. This allows determining the start of said restoration or maintenance process, etc.

[0114] According to the foregoing, the processing unit 300 and the support 170 constitute an automated system to control and determine the loading of the charge 210 for supplying the furnace 100 .

[0115] In the following claims, references in parentheses are for the sole purpose of facilitating reading and they are not to be construed as limiting factors with respect to the scope of protection claimed in a particular claim.

Claims

1. A weighing device, the weighing device being configured to weigh a charge (210) fed into an electric arc furnace (100) resting on a horizontal pivoting platform (160), the weighing device comprising a plurality of supports (170), each of the supports comprising an upper plate (172a), a lower plate (172b) and a weighing element (171), the upper plate (172a) and the lower plate (172b) being arranged parallel to each other during use, the weighing element (171) being in contact with the two plates (172a, 172b) and being arranged in the middle of the two plates (172a, 172b), characterized in that The weighing element (171) is a column type weighing sensor and is characterized in that: Each support member (170) includes two connecting elements (173), which are perpendicular to each other and located on a plane parallel to the plane defined by the upper plate (172a) and the lower plate (172b), and each connecting element has a tie rod (173c), which is connected to at least one upper terminal (173a) for connecting to the upper plate (172a) and at least one lower terminal (173b) for connecting to the lower plate (172b).

2. The weighing device according to claim 1, characterized in that: The upper plate (172a) is configured to contact the furnace (100), and the lower plate (172b) is configured to contact the horizontal pivoting platform (160) supporting the furnace.

3. The weighing device according to claim 1 or 2, characterized in that: The weighing device comprises at least three supports (170) evenly distributed relative to each other.

4. A weighing device according to any one of the preceding claims, characterised in that Each support (170) includes a cooling shell (177) to control the temperature of the associated weighing element (171).

5. A weighing device according to any one of the preceding claims, characterised in that The at least one weighing element (171) comprises a central rod (171a) configured to support at least a portion of the weight of the furnace (100), the weight of its contents and the weight of each element mounted in or on the furnace (100).

6. The weighing device according to claim 5, characterized in that: The central rod (171a) includes at least two deformation sensors.

7. The weighing device according to claim 5 or 6, characterized in that: The center rod (171a) is attached to the lower plate (172b).

8. The weighing device according to claim 5 when referring to claim 4, characterized in that The cooling shell (177) is a hollow cylindrical shell which at least partially surrounds the central rod (171a) and allows a cooling liquid (177c) to circulate therein, wherein the cooling liquid (177c) is introduced into the cooling shell (177) through an inlet nozzle (177a) and is led out of the cooling shell (177) through an outlet nozzle (177b).

9. An automated system for controlling the feeding of a charge (210) into an electric arc furnace (100), the electric arc furnace comprising an electrode (150), characterized in that: The automation system comprises: - a weighing device according to any of the preceding claims, configured to weigh the furnace (100), its contents and each element mounted in or on the furnace (100), wherein a support (170) of the plurality of supports (170) is inserted between the furnace (100) and a horizontally pivoting platform (160); - a processing unit (300) configured to control the amount of charge (210) fed to the furnace (100) as a function of the value of energy delivered in the furnace, based on the information received from the weighing device.

10. The automation system according to claim 9, characterized in that The value of the energy delivered within the furnace (100) corresponds to the combination between the value of the electrical power supplied to the electrode (150) during a melting sequence and the value of the chemical energy supplied to the bath (200) of the molten metal charge and generated by auxiliary elements such as electrodes, burners, lances or tuyere.

11. An apparatus (10) comprising an electric arc furnace (100), characterized in that The apparatus (10) comprises an automation system according to claim 9 or 10 to control the feeding of charge material (210) into the furnace (100).

12. The device (10) according to claim 11, characterized in that The support member (170) is arranged along the outer circumference of the furnace (100).

13. The device (10) according to claim 11 or 12, characterized in that The apparatus (10) comprises a conveying element (135) configured to convey and introduce the charge material (210) into the furnace (100).

14. A method for controlling the feeding of charge (210) into an electric arc furnace (100) during a melting sequence, the method being performed by an automated control system according to claim 9 or 10, characterized in that The method comprises the following steps: - determining, by means of the weighing element (171), a plurality of weight values ​​of the furnace (100), its contents and each element installed in or on the furnace (100) at different moments in time; - obtaining a value of the total energy supplied to the bath (200) defined by the molten charge by said processing unit (300); - Based on the total energy value and the weight value, controlling by the processing unit (300) the amount of charge material (210) to be introduced into the furnace (100) by means of a conveying element (135) for the charge material (210).

15. The control method according to claim 14, characterized in that: Obtaining a value for total energy supplied to the molten bath (200), comprising obtaining the total energy value based on values ​​of electrical power supplied to one or more electrodes (150) during a melting sequence and values ​​of chemical energy generated by auxiliary elements such as electrodes, burners, lances or tuyere.

16. The control method according to claim 14 or 15, characterized in that: Controlling the amount of charge (210) to be introduced into the furnace (100) comprises controlling the speed of the conveying element (135) by the processing unit (300), the conveying element (135) being a conveyor belt.

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