阅读说明：本技术 用于测量和控制送入炉子的装载材料的装置 (Device for measuring and controlling the load material fed into a furnace ) 是由 D·洛卡特利 S·M·瑞丽 P·阿尔杰塔 于 2019-06-27 设计创作，主要内容包括：一种测量和控制将装载材料送入电弧炉(EAF)的系统和设备,包括：自动控制装置,用于送入装载材料；测量装置,其定位在EAF和倾斜平台之间,包括适于抵靠EAF滑动的上板、接合到倾斜平台的下板、以及在它们之间的具有周边环形壁的环形结构、延伸跨过环形结构的环形板、以及联接到环形板的接触构件,该接触构件上部接触上板并且下部接近而不接触下板；以及一个或多个传感器,其测量在所述上板上施加载荷时所述环形板的变形。(A system and apparatus for measuring and controlling the feeding of a load material into an Electric Arc Furnace (EAF), comprising: an automatic control device for feeding the loading material; a measuring device positioned between the EAF and the inclined platform, comprising an upper plate adapted to slide against the EAF, a lower plate joined to the inclined platform, and an annular structure having a peripheral annular wall therebetween, an annular plate extending across the annular structure, and a contact member coupled to the annular plate, the contact member contacting the upper plate at an upper portion and the lower portion approaching without contacting the lower plate; and one or more sensors that measure deformation of the annular plate when a load is applied to the upper plate.)

1. An apparatus for measuring and controlling a charge material fed into an Electric Arc Furnace (EAF) placed on a tilting platform, the apparatus comprising:

an automatic control device that supplies the load material in accordance with the energy supplied to the molten pool; and

a measuring device for the load material, the measuring device operably coupled to the automated control device, the measuring device weighing a housing of the EAF, contents of the housing, and any other components supported by the housing,

wherein the measuring device is adapted to be positioned between the EAF and the inclined platform and comprises:

an upper plate having an upper surface adapted to slide against a lower surface of the EAF;

a lower plate having a lower surface adapted to be joined to the inclined platform;

an annular structure coupled to an upper surface of the lower plate and having:

a peripheral annular wall having a longitudinal axis perpendicular to the upper and lower plates,

an annular plate coupled to the inside of the annular wall and extending across the annular structure, an

A contact member coupled to the annular plate and extending along the longitudinal axis of the annular structure to contact the lower surface of the upper plate from above and contactlessly approach the upper surface of the lower plate from below, and

one or more sensors coupled to the annular plate and measuring deformation of the annular plate when a load is applied on the upper surface of the upper plate.

2. The apparatus of claim 1, wherein the upper surface of the upper plate is made of wear resistant steel.

3. The apparatus of claim 1, wherein the lower surface of the EAF in contact with the upper surface of the upper plate is made of wear resistant steel.

4. The apparatus of claim 1, wherein the annular wall has a circular perimeter.

5. The apparatus of claim 1, wherein the annular plate is parallel to the upper and lower plates and is closer to an upper end of the annular wall than to a lower end of the annular wall.

6. The apparatus of claim 1, wherein the contact member has a convex upper end, thereby minimizing a contact area between the contact member and the upper plate.

7. The apparatus of claim 1, wherein the contact member has a flat lower end that acts as a travel limit in the event of an overload, thereby preventing breakage of the measurement device.

8. The apparatus of claim 1, wherein a plurality of sensors are disposed on opposite sides of the contact member.

9. The apparatus of claim 1, wherein the one or more sensors are one or more strain gauges that measure strain of the annular plate when a load is applied on the upper surface of the upper plate.

10. The apparatus of claim 1, further comprising a plurality of rods connecting the upper plate to the lower plate on opposite sides of the upper and lower plates.

11. The apparatus of claim 10, wherein the plurality of rods comprises two rods diagonally disposed in opposite directions.

12. The apparatus of claim 10, wherein the plurality of rods comprises three rods joined in a stepped pattern on each of the opposing sides of the upper and lower plates, the three rods comprising a first rod extending downwardly from a first lateral end of the upper plate, a second rod extending upwardly from an opposing lateral end of the lower plate, and a third rod parallel to the upper and lower plates and connecting a lower end of the first rod and an upper end of the second rod.

13. The apparatus of claim 1, further comprising a data acquisition system of readings of one or more measurements provided by one or more of the sensors.

14. The apparatus of claim 1, wherein the automated control device is configured to continuously feed the loading material into the EAF.

15. A system for refining steel, comprising:

an Electric Arc Furnace (EAF) that produces steel by melting and refining a charge material within the EAF;

a conveyor connected to the EAF to introduce the loading material into the interior of the EAF;

a secondary combustion station cooperating with the conveyor and preheating the load material within the conveyor;

an inclined platform for inclining the EAF for slag and tap operations, the inclined platform being positioned such that the inclination of the EAF retains a heel of molten liquid material within the EAF, the heel having a weight of 10% to 50% of a pre-tap weight; and

an apparatus configured to measure and control the supply of the loading material to the EAF, the apparatus positioned between the EAF and the inclined platform, the apparatus comprising:

an automatic control device that supplies the load material in accordance with the energy supplied to the molten pool; and

a measuring device for the load material, the measuring device operably coupled to the automated control device, the measuring device weighing a housing of the EAF, contents of the housing, and any other components supported by the housing,

wherein the measuring device is located between the electric arc furnace and the tilting platform and comprises:

an upper plate having an upper surface adapted to slide against a lower surface of the EAF;

a lower plate having a lower surface adapted to be joined to the inclined platform;

an annular structure coupled to an upper surface of the lower plate and having,

a peripheral annular wall having a longitudinal axis perpendicular to the upper and lower plates,

an annular plate coupled to the inside of the annular wall and extending across the annular structure, an

A contact member coupled to the annular plate and extending along a longitudinal axis of the annular structure to contact the lower surface of the upper plate from above and contactlessly approach the upper surface of the lower plate from below, an

One or more sensors coupled to the annular plate and measuring deformation of the annular plate when a load is applied on the upper surface of the upper plate.

16. The system of claim 15, wherein the contact member has a convex upper end thereby minimizing a contact area between the contact member and the upper plate and a flat lower end thereby maximizing a contact area between the contact member and the lower plate when the annular plate is deformed downwardly.

17. The system of claim 15, further comprising a plurality of rods connecting the upper plate to the lower plate on opposite sides of the upper and lower plates.

18. The system of claim 17, wherein the plurality of rods comprises two rods diagonally disposed in opposite directions.

19. The system of claim 17, wherein the plurality of rods comprises three rods joined in a stepped pattern on each of the opposing sides of the upper and lower plates, the three rods comprising a first rod extending downwardly from a first lateral end of the upper plate, a second rod extending upwardly from an opposing lateral end of the lower plate, and a third rod parallel to the upper and lower plates and connecting a lower end of the first rod and an upper end of the second rod.

Technical Field

The present invention relates to an apparatus and related method for measuring and controlling the feeding of load material and scrap into a furnace, in particular for measuring and controlling continuous feeding.

Background

The use of continuous systems for loading scrap metal into a furnace, in particular into an Electric Arc Furnace (EAF) for steel production, such as the systems described above and/or the addition of previously reduced material to the bath, involves the need to maintain direct control of the flow of the loaded material as it enters the furnace.

In fact, this causes problems of reducing the overall efficiency of the production cycle if the continuous addition of solid loading material cannot be controlled continuously and correctly. Among these problems, it is of utmost importance that a thickened solid material is formed in the scrap unloading zone in the furnace, since it maintains this consistency for a long time, thereby prolonging the smelting time in the furnace and, consequently, the overall production cycle.

This control is also important in order to ensure that the supply of power to the electrodes is as uniform as possible, while avoiding direct contact between the solid material and the electrodes, which could lead to breakage of the electrodes.

In normal practice, the control is performed by an operator, a line controller, who manually adjusts the scrap loading system speed according to his personal experience and his impression of the amount of loading material or scrap loaded in the furnace. Of course, this operator must be very familiar with the process and installation, and in any case, his decision may still always be influenced by an uncertain and not very reliable data reading.

One solution to these problems is to provide a furnace comprising a continuous furnace shell weight control device.

To achieve this, two types of measurements were developed: indirect furnace shell weight control methods based on liquid metal level, and more direct control methods based on sensors measuring system weight.

The indirect control method is based on a geometric method which, starting from the reading of the liquid level, converts this data into volumetric data (and therefore weight), which obviously depends on the presumed contour of the refractory storage tank inside the furnace shell.

However, the furnace shell profile is strictly related to the phenomenon of erosion caused by the liquid metal in the refractory material, which is often violent and unpredictable. Inevitably over time this results in a lack of accuracy in the tare curve used to compare the level readings with the volume calculations. Considering the lack of precision and the high specific gravity of iron, the measured data will show considerable errors, and therefore this technique cannot be used for precision control.

In the case of the direct control method, i.e. the method based on direct weighing of the furnace shell structure, the weight reading system must be located in a specific area, such as the support columns and beams, which, however, not only support the weight of the furnace shell, but also all the support structures, systems and subsystems of the furnace. Thus, the amount of load material or scrap metal included constitutes only a limited percentage of the measured weight, and this involves all aspects of lack of accuracy. This lack of accuracy becomes so severe that any measurement performed is considered reliable only when quality is considered.

In the case of wheel mounted tilt furnaces (and weighing systems on the wheels), it is the weight of the furnace housing tilt system that must be able to withstand the strong mechanical stresses to increase the total read weight, thereby sacrificing measurement accuracy.

Disclosure of Invention

The general object of the present invention is therefore to solve the above-mentioned problems in a simple, economical and particularly practical manner.

The object of the present invention is an apparatus for measuring and controlling the charge material or scrap metal fed into an electric arc furnace, which apparatus has automatic means for controlling the charge material or scrap metal feed according to the energy fed into the bath, and means associated with the automatic control means for measuring the amount of charge material added, which means comprise means for weighing the furnace shell, its contents and any other components it can support.

Another object of the invention is to provide a method for measuring and controlling the feeding of a load material or scrap metal into an electric arc furnace, comprising the steps of:

weighing the charge material or scrap metal added to the bath by means of a device that weighs the furnace shell, its contents and any other components it can support;

data acquisition of measurement readings of the amount of load material or scrap metal added to the bath provided by the weighing device, said readings being differentiated (differential) for example over a period of time;

optimizing the load flow according to a suitable algorithm obtained by adjusting the feed rate of the load material or scrap metal according to the energy supplied to the bath;

preferably, the feeding of the load material or scrap metal into the electric arc furnace should be continuous.

In particular, the means for measuring the weight of the furnace shell and any other components it can support provide the furnace shell with a support structure consisting of support rollers.

The function of such a roller is to recover any shape deviations caused by thermal cycling.

Furthermore, the weighing device operates in a dual redundant manner, operating at least on two of the support rollers comprising the measuring rollers. Preferably, therefore, at least two support rollers mounted on the device according to the invention are used as measuring rollers.

The measuring roller is equipped with a sensor for direct or indirect weight reading.

The third support roller can also be used as a measuring roller, which is equipped with a sensor for direct or indirect weight reading.

Another apparatus for measuring shell weight according to the present invention is configured to be positioned between an Electric Arc Furnace (EAF) and a tilt platform, and includes an upper plate having an upper surface adapted to slide against a lower surface of the EAF, a lower plate having a lower surface configured to be joined to the tilt platform, an annular structure coupled to the lower plate and having a peripheral annular wall, an annular plate coupled to an inner side of the annular wall and extending across the annular structure, and a contact member coupled to the annular plate and extending along a longitudinal axis of the annular structure to contact the lower surface of the upper plate upward and approach downward without contacting the upper surface of the lower plate, and further includes one or more sensors coupled to the annular plate that measure deformation of the annular plate when a load is applied on the upper surface of the upper plate.

The sensor may be a strain gauge that measures the strain applied to the annular plate.

The automatic device for controlling the feeding of load material or scrap metal according to the invention also comprises a connection and control system for the device for feeding load material or scrap metal. Basically, the automatic means or system for management and control take readings of the precise measurements provided by the weighing means, differentiated over a period of time, which measure in a continuous manner the amount of load material or scrap metal added to the bath by weighing the furnace shell, its contents and all the components it can support.

The automatic management and control system therefore operates on the scrap metal feed rate, according to the algorithm for optimizing the load flow, to prevent any solid agglomerates formed from being sent into the bath at any energy level (electrical and/or chemical).

The main advantage of the apparatus and method according to the invention is that by controlling the ratio between the energy supplied and the weight of the material (scrap) loaded, it is possible to control the temperature of the liquid metal, keeping it close to the ideal value of the cycle, and to be able to operate constantly at the maximum energy produced by the bath, thus contributing to an increase in production efficiency.

Furthermore, this helps to prevent any human error due to insufficient accuracy in the calculation of the operating conditions.

Another advantage is the reduction of technical information requests from the general operator on the production line, who will have the support of a system capable of analyzing the conditions in real time, helping him to make appropriate decisions automatically and in real time.

The solution adopted according to the invention is particularly advantageous in terms of weighing devices, since it is based on the selection of a general furnace configuration, derived from well-tested designs and configuration schemes, but adds an absolutely innovative data acquisition method.

The proposed construction of the furnace is based on the separation of various functions: the function of containing the smelting material requires a compact structure, as light as possible, consisting only of the furnace shell and any other components it can support. The support and tilting of the furnace shell (complete emptying of the furnace shell for maintenance or remaking during tapping) requires the provision of a support structure from below. This configuration has proved to be most suitable for the implementation of a weighing system, since it provides an optimal ratio between the material treated (load material or scrap metal to be fed into the furnace) and the total weight applied on the weighing system.

In fact, in the solution according to the invention, the furnace shell is weighed on the supporting structure by means of rollers or other different weighing devices, with the additional function of recovering any shape deviations caused by thermal cycles. Such rolls or other different weighing devices support the structures involved in smelting as little as possible and they are therefore the best solution to provide an efficient instrument aimed at monitoring the weight of the scrap metal to be added.

However, given the geometry of the coupling between the furnace shell and the support structure, other embodiments are also possible, such as an accurate measurement system to calculate the distance between the furnace shell and the support structure or any furnace shell weighing system suitable for controlling the scrap metal or load material supply.

The apparatus and method according to the invention are also applicable to all operating methods involving the addition of liquid or solid metal in a more or less continuous manner during the operating cycle.

Although the specific apparatus and method for measuring and controlling the charge material and scrap metal fed into the furnace for steel production is closely related to the specific construction scheme of the furnace shell, it can also be applied to other methods. Another object of the present invention is to provide a method for steel refining comprising:

continuously preheating the load material;

feeding iron-bearing material, direct reduced iron, or a mixture of both into an electric arc furnace in order to perform smelting and refining operations; -feeding elements in a molten bath for steel production to form a slag;

introducing a carburizing element into a furnace for steel production;

electrically heating the load using electrodes to melt the load and form a molten metal bath in the furnace with a layer of molten slag on the molten metal bath;

maintaining the slag in a foamed state during steel production; -feeding a metal element as slag former and a carburizing element into the furnace;

maintaining full power capacity in the furnace for the total charging, smelting and refining time;

intermittently tapping from the furnace, maintaining a liquid metal heel (heel) within the furnace shell, the weight of the liquid metal heel varying substantially between 10% and 50% of the weight prior to tapping;

this method is characterized in that the step of charging the material or scrap metal in the electric arc furnace, i.e. the iron-containing material, the direct reduced iron or the mixture of both, comprises the following sub-steps:

the weight of the charge material or scrap metal added to the bath is provided by weighing means by weighing the furnace shell, its contents and any components it can support.

Data are collected, such as time difference, and a measurement reading is the amount of charge material or scrap metal added to the bath and provided by the weighing device.

The load flow is optimized according to a suitable algorithm by adjusting the feed rate of the load material or scrap metal according to the energy supplied to the bath.

Another object of the present invention is to provide an apparatus for refining steel, comprising:

an electric arc furnace for making steel for melting and refining a metal load in the furnace;

an electrode extending within the furnace up to the intermediate slag level and the level of molten material contained in the molten bath;

a feeder means connected to said furnace for introducing a charge material into said furnace without removing the electrodes;

a post-combustion (post-combustion) device cooperating with the feeding device to preheat the charge material within the feeding device;

means for measuring and controlling the feeding of the load material or scrap metal, consisting of automatic control means for the load material or scrap metal and means for measuring the added load material, associated with the automatic control means;

a hermetically sealed mechanical device located in an inlet section of the load material or scrap metal to the feeder;

gas injection means in communication with said furnace above and/or below the normal molten metal level in the bath; and

means for tilting the furnace for tapping and tapping operations, the tapping means being positioned in such a way that the ramp of the furnace will hold a heel of molten liquid material inside the bath, the heel having a weight varying between about 10% and 50% of the weight before tapping.

Drawings

The structural and functional characteristics of the present invention and its advantages with respect to the prior art will become more apparent and more evident from the following description, with reference to the attached drawings, in which:

figures 1 and 2 are side views of a solution according to the prior art;

FIGS. 3 and 4 are side views of a system according to the present invention;

FIG. 5 is a block diagram of a method according to the present invention;

6A-6C are cross-sectional, elevational, and top views of a system according to the present invention;

FIGS. 7A-7B show side views of the system of FIGS. 6A-6C in rest and deformed states;

FIGS. 8A-8C are cross-sectional, elevation, and plan views of a system according to the present invention;

FIG. 9 shows a side view of the system of FIGS. 8A-8C in a deformed state; and

fig. 10 shows the system of fig. 6A-6C and 8A-8C in a resting and loaded state.

Detailed Description

The term "charge material" or "scrap metal" as used in the present description and claims refers to charge material for continuous smelting, including scrap iron, cast iron, direct reduced iron in the form of iron flakes or chips and/or mixtures of both. In particular, unless otherwise specified, the term "loading material" includes scrap metal. In the present description and claims, unless otherwise indicated, the term "load material" is meant to include scrap metal.

Fig. 1 shows an Electric Arc Furnace (EAF) supported by a tilting platform 5 (for slagging, tapping or emptying operations) with wheels 3 on a supporting base 6.

The housing 1 of the EAF is arranged on a tilting platform 5 by means of suitable supports 2.

The side opening 4' of the EAF is used for feeding scrap metal, if necessary, by means of a conveyor 4, using a continuous feeding procedure, for example in a system. Conventional arrangements are sometimes equipped with instruments for reading the weight via sensors located in the axis of the EAF furnace support wheel 3.

In contrast, fig. 3 and 4 show an embodiment of the present invention. The inclined platform 5 is mounted on a support base 6 and the furnace shell 1 is arranged on suitable supports 2 on the platform 5. in order to allow structural stability due to exposure to potentially high temperatures, the furnace shell support system comprises at least two rollers 7, with weight readers or sensors mounted within the rollers 7.

By way of example only and not limitation, these sensors may be mounted in the shaft of the roll 7 with dual redundancy and are shear stress sensors. As shown in fig. 3, the weighing section consists only of the furnace shell 1, whose weight is much smaller than that shown in fig. 1 (furnace shell 1 plus inclined platform 5). Thus, at smaller strains, the sensors in the roll 7 can be designed with much greater accuracy capabilities.

The data acquisition reading (see fig. 5) together with suitable calculation algorithms enables the progressive monitoring of the scrap metal fed into the furnace shell 1 in real time through the opening 4' by means of the conveyor 4, then the data acquisition system (fig. 5) also processes this information according to the energy at the furnace inlet, making it available to the production line operators, as well as to the continuous scrap metal feed control system 4 as described in fig. 5 (for example, as in the system).

Or, in the case of tilting furnaces without wheels (as in the type shown in fig. 2 in the current version according to the prior art), which have a weight that is hardly measurable, the application of the solution according to the invention enables the real-time measurement (fig. 4) of the load material and has a considerable impact on the simplification of the construction of EAF systems with possible continuous feeding devices (as in the system, for example).

Fig. 6-10 show another embodiment of a measuring device according to the invention.

As in the previous embodiment, the measuring device 10 operates as a load cell and is positioned between the housing 11 and the inclined platform 12 of the EAF, in its basic elements the measuring device 10 comprising an upper plate 13 facing the housing 11; a lower plate 14 facing the inclined platform 12; an annular structure 15 disposed therebetween and having a peripheral annular wall 16, an annular plate 17 opposite the annular wall 16, and a contact member 18 extending through the annular plate 17; and one or more sensors 19 that measure the deformation of the annular plate 17 when a load is applied to the contact member 18 through the upper plate 13.

The upper plate 13 faces the housing 11 and has an upper surface 20 adapted to slide against the housing 11. In one embodiment, the upper surface 20 is made of a wear resistant material, such as wear resistant steel. Alternatively, the abradable material may be applied to the bottom of the furnace shell in the area facing and contacting the upper surface 20. Alternatively, the abradable material may be applied on both sides of the interface between the bottom of the furnace shell and the upper surface 20.

While the lower plate 14 is adapted to be fixedly joined to the tilting platform 12, in the rest position the lower plate 12 is substantially parallel to the upper plate 11 and may, in one embodiment, be joined to the lower plate 12 using bolts.

The ring structure 15 is disposed on the lower plate 14 and may or may not be fixedly attached to the lower plate 14. The ring structure 15 may have a variety of peripheral shapes, for example, may have a circular periphery, thereby providing the ring structure 15 with a cylindrical shape.

The annular wall 16 has a longitudinal axis perpendicular to the upper and lower plates 13, 14 and supports, on its inner side, an annular plate 17 in the form of a membrane spanning the annular structure 15, preferably in a direction parallel to the upper and lower plates 12, 14. The thickness of the annular plate 17 is less than the height of the annular wall 16 and does not necessarily subtend an intermediate position between the upper and lower ends of the annular wall 16, in the embodiment shown, for example, the annular plate 17 is closer towards the upper end of the annular wall 16, at about 2/3 of the height of the annular wall 16.

The contact member 18 extends along the longitudinal axis of the annular structure 15 and has an upper end 21 contacting the lower surface of the upper plate 13, and a lower end 22 positioned, in the rest position, at a distance from the lower plate 14 below that enables the contact member 18 to move downwards when the annular plate 17 is deformed, as will be explained below. In the embodiment shown, the contact members 18 are integral with the annular plate 17, so that the annular plate 17 defines a circular crown connecting the annular wall 16 to the contact members 18.

The upper end 21 of the contact member 18 is preferably convex in order to minimize the contact surface between the contact member 18 and the upper plate 13 and to enable a tilting movement of the upper plate 13 relative to the contact member 18, as will be explained later. The lower end 22 of the contact member 18 instead has a flat shape and acts as a travel limit in the event of an overload, limiting deformation of the load cell and thus preventing the load cell from cracking.

In the embodiment shown, there are four sensors 19 equally spaced on the annular plate 17 around the contact member 18. Those skilled in the art will appreciate that a different number of sensors 19 may be used, and that the sensors 19 may be spaced apart at different distances as desired.

The sensor 19 measures the deformation of the annular plate 17 when a load applied to the upper end 21 of the contact member 18 causes a downward pressure on the contact member 18, in one embodiment the sensor 19 is a strain gauge that measures the strain applied to the annular plate 17.

The sensor 19 is connected to a data acquisition system that acquires readings of one or more measurements provided by the sensor 19.

A plurality of rods 23 connect the upper plate 13 to the lower plate 14 and are disposed on opposite sides of the upper and lower plates 13 and 14, and fig. 6A, 6B and 6C illustrate one embodiment of the invention in which two rods 23 and 24 are disposed on opposite sides of the upper and lower plates 13 and 14, respectively, and extend diagonally in opposite directions, such that the rod 23 connects the upper "right" end of the upper plate 13 with the lower "left" end of the lower plate 14 on one side of the measuring device 10, and the rod 24 connects the upper "left" end of the upper plate 13 with the lower "right" end of the lower plate 14 on the opposite side of the measuring device 10.

The purpose of the rods 23 and 24 is not only to provide a connection between the upper and lower plates 13, 14, but also to substantially eliminate horizontal shear stresses on the measuring device 10 extending parallel to the upper and lower plates 13, 14, and in addition, the rods 23 and 24 can accommodate small misalignments between the housing 11 and the tilting platform 12.

Fig. 7A and 7B further illustrate how the rods 23 and 24 can make a small relative rotation between the upper plate 13 and the lower plate 14.

8A-8C illustrate an embodiment of the invention in which there are three rods connecting the upper plate 13 to the lower plate 14, which are arranged in a stepped pattern on opposite sides of the measuring device 10, first considering the "left" side of the measuring device 10, with a first rod 25 extending down one end of the upper plate 13, extending about half the distance between the upper plate 13 and the lower plate 14; the second rods 26 extend upward from opposite ends of the lower plate 14, and also extend about half the distance between the upper plate 13 and the lower plate 14; a third bar 27 connects the lower end of the first bar 25 to the upper end of the second bar 26 in a direction parallel to the upper and lower plates 13, 14, and three bars 28, 29, 30 also connect opposite sides of the upper and lower plates 13, 14 in a mirror image pattern, so that the second bars 26 and 29 extend upwardly from the lower plate 14 at diagonally opposite corners of the lower plate 14 if the lower plate 14 is square.

Fig. 9 shows the deformation of the measuring device 10 in the last described embodiment when the housing 11 becomes misaligned relative to the tilting platform 12.

Fig. 10A-10B illustrate the mode of operation of the measurement device 10. As can be seen, the downward pressure applied to the contact members 18 causes the contact members 18 to translate downwardly toward the lower plate 14, and also causes the circular crown defined by the ring plate 17 between the annular wall 16 and the contact members 18 to deform in a substantially conical manner to accommodate such downward translation.

Similar to the first embodiment, the system including the measuring device 10 may also include a conveyor connected to the EAF that introduces the load material into the interior of the EAF, and a post-combustion station cooperating with the conveyor that preheats the load material within the conveyor. The automatic control means may cause the load material to be continuously fed into the EAF.

Furthermore, the inclined platform 10 may be adapted to incline the EAF for tapping and tapping operations and positioned such that the inclination of the EAF retains within the EAF a heel of molten liquid material weighing between 10% and 50% of the weight prior to tapping.

It should be noted that with the above-described apparatus it is possible to obtain data of the measured readings of the amount of load material or scrap metal added to the bath differentially in time, so that the load flow optimization can be calculated using a suitable algorithm. Based on these data, the apparatus and system according to the invention enable the feed rate of the load material or scrap metal to be adjusted.

The measuring device constructed as shown in fig. 6-10 provides several advantages, even better than the measuring devices shown in fig. 3 and 4, some of which can be summarized as follows:

the precision is higher: while the measuring device shown in fig. 3-4 provides a level of accuracy on the order of 2%, the measuring device shown in fig. 6-10 provides a level of accuracy of 0.3-0.5% by providing a more accurate reading of the bending deformation of the circular crown defined by the annular plate 17;

easier maintenance: the measuring devices shown in fig. 3-4 may have a weight of several hundred kilograms, including rollers and shafts, which makes handling difficult for an operator. The measuring device shown in fig. 6-10 has a small volume, a weight in the range of 10-20kg, which can be operated by a single operator. This provides for easier replacement, not only when the EAF is fully lifted for maintenance, but even without lifting the EAF by locally acting hydraulic lifters or jacks to extend the facing surfaces of the upper and lower plates a limited distance, in order to release and replace the measuring device;

the cost is low: the measuring devices shown in fig. 3-4 are not only heavier, but also require a greater number of machined parts than the measuring devices shown in fig. 6-10, which have fewer mechanical parts and lower weight, thereby reducing production costs.

While the invention has been described in connection with the above-described embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the scope of the invention. Furthermore, the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art, and is limited only by the terms of the appended claims.