Method and system for determining a series of temperature values ​​of a molten metal bath - Patents.com

Abstract

The present invention relates to a method and system for determining a series of at least two temperature values ​​of a molten metal bath using an apparatus comprising an optical core wire and a detector. The method according to the invention has proven particularly suitable for multiple repeated measurements in which the temperature of the molten metal bath varies between measurements, and in which the molten metal bath reaches a final end temperature.

Description

[Technical field]

[0001] The present invention relates to a method and system for determining a sequence of at least two temperature values ​​of a molten metal bath. [Background technology]

[0002] The temperature of the molten metal bath in a metallurgical vessel is a critical parameter during the metal manufacturing process and determines the quality of the resulting product. A possible means for measuring the temperature of a molten metal bath, especially iron or steel in the melting environment of an electric arc furnace (EAF), involves immersing an optical fiber surrounded by a metal tube into the molten metal. The optical fiber surrounded by a metal tube is often also referred to as an optical core wire.

[0003] Because heating a metal melt is an energy intensive process, it is desirable to avoid overheating the molten metal, ie, heating it above a critical temperature that allows optimal processing of the melt.

[0004] To measure the temperature of the molten metal bath, the optical core wire can be sent into the metallurgical vessel. The front end of the optical core wire is immersed in the molten metal bath, and on the way there first encounters a high temperature atmosphere, then a slag layer, and then the molten metal bath. When a portion of the optical core wire is immersed below the surface of the molten metal bath, the optical fiber can transmit the thermal radiation received from the molten metal to a detector, for example a pyrometer. A suitable instrument can be associated with the detector to determine the temperature of the molten metal bath. During this measurement, the immersed portion of the optical core wire can be partially or completely consumed by the molten metal bath. Once the temperature measurement is finished, the tip of the optical core wire can be retracted from the molten metal bath. The retracted tip of the optical core wire becomes the new front end for the next temperature measurement.

[0005] Such devices are suitable for on-demand and semi-continuous temperature measurements in the form of a series of immersion cycles, allowing an operator to obtain temperature measurements without directly intervening in the hostile environment proximate to the metallurgical vessel.

[0006] To provide accurate measurements, blackbody conditions must be ensured near the immersed front end of the optical fiber while measurements are being taken. The fiber must be immersed to a sufficient depth below the metal bath surface and at a location within the vessel that is representative of the temperature of the liquid metal bath. On the other hand, deep immersion increases the buoyant forces on the optical core wire, increasing wear and tear on the optical core wire during the measurement sequence.

[0007] Several prior art documents disclose methods of routing metal-coated optical fibers to improve the data quality of temperature measurements.

[0008] For example, US2018180484 discloses a method suitable for multiple measurement cycles without the need for additional equipment. However, the disclosed method does not take into account the final state to be reached at the end of the melting process, i.e. the final temperature at which the melting process ends. It also does not take into account the constantly changing conditions in the metal manufacturing process, in particular the temperature rise of the molten metal. This can lead to an unnecessarily large number of measurements or measurements at inappropriate times during the process.

[0009] US2014130636 discloses a method for controlling a melting process in an electric arc furnace. Process parameters are obtained to determine the state of the process, and the process is adapted based on the obtained parameters according to predetermined values ​​of the parameters. Optimization of the process itself is disclosed, but optimization of the application of the associated measurements is not mentioned.

[0010] In view of the prior art, there is a need for measurement methods and systems that take into account the attendant aspects of the metal manufacturing process, as well as efficient methods of using these methods and systems.

[0011] It is therefore an object of the present invention to provide an improved method for determining a sequence of at least two temperature values ​​of a molten metal bath, which solves at least one of the above mentioned problems. In particular, it is an object of the method according to the invention to provide a method which makes it possible to carry out a metal production process until a final end temperature value is reached with a minimum number of temperature measurements. More specifically, it is an object to provide a method which makes it possible to avoid overheating of the molten metal bath. In particular, one of the objects is to provide a method which makes it possible to minimize wear and tear of the optical core wire during the sequence of measurements.

[0012] It is a further object of the present invention to provide an improved system for determining a series of at least two temperature values ​​of a molten metal bath.

[0013] These objects are achieved by the subject matter defined in the independent claims.

[0014] The present invention relates to a method for measuring a series of at least two temperature values ​​T of a molten metal bath using an apparatus comprising an optical core wire and a detector. mes (n) and T mes (n+1), comprising the steps of: (a) providing a model F(t) describing the temperature profile of a molten metal bath over time; (b) Critical temperature value T cri Defining (c) The measured temperature value T of the molten metal bath at time t(n) mes (n) measuring the (d) Model F(t), critical temperature value T cri , and the measured temperature value T mes Based on (n), the fitted heating rate R heat (n), wherein R heat (n) is R heat (n) = ΔT heat (n) / Δt and (e) Critical temperature value T cri and the measured temperature value T mes(n) and the fitted heating rate R heat (n) and time t cal (n+1), ΔT(n)=T cri -T mes (n) and t cal (n+1)=t(n)+(ΔT(n) / R heat (n) The process and (f) Time t cal The measured temperature value T of the molten metal bath at (n+1) mes (n+1); The present invention provides a method comprising:

[0015] Furthermore, the present invention provides a method for determining a temperature of a molten metal bath by a series of at least two temperature values ​​T mes (n) and T mes A system for determining (n+1), the system comprising an apparatus and a module, the module adapted to interact with the apparatus, the apparatus comprising an optical core wire and a detector, the module comprising a storage unit, a processing unit, and a control unit; The storage unit is (a1) a memory element for providing a model F(t) describing the temperature profile of a molten metal bath over time; (a2) Critical temperature value T cri A storage element for defining Including, The processing unit is (b1) Model F(t), critical temperature value T cri , and the measured temperature value T mes Based on the fitted heating rate R heat A processing element for determining R heat teeth, R heat =ΔT heat / Δt a processing element defined as (b2) Critical temperature value T cri and the measured temperature value T mes and the temperature difference ΔT and the fitted heating rate Rheat Based on this, at time t cal A processing element for calculating ΔT=T cri -T mes and t cal =t+(ΔT / R heat ), A processing element; Including, The control unit (c1) Temperature value of the molten metal bath T mes

[0033] Including a control element for measuring Provide a system.

[0016] Further preferred embodiments are defined in the dependent claims. The preferred embodiments may be realized both individually and in any possible combination.

[0017] The method according to the invention has been proven to be particularly suitable for multiple repeated measurements where the temperature of the molten metal bath changes between measurements and where the molten metal bath reaches a final end temperature. Typically, the temperature of the molten metal rises between measurements due to continued heating and overheating, i.e. heating above the final end temperature to be reached, should be avoided. In addition, the method has been proven to support the efficient application of several measurements to bring the heat to the final end temperature, i.e. to ensure that this target temperature is reached at the end of the process. In other words, underheating at the end of the process can also be avoided. Furthermore, the method of the invention allows the optimization of the timing and number of measurements, thereby resulting in an optimal minimum wear of the optical core wire. The term "wear" as used herein refers to damage to the optical core wire, such as, for example, melting and dissolving of the optical core wire by and into the molten metal bath, decomposition or burning of the entire optical core wire or different parts thereof.

[0018] The present invention relates to a series of at least two temperature values ​​T mes (n) and T mes(n+1). A sequence of temperature values ​​is used herein to describe a determination that is repeated at least once. The sequence of temperature values ​​includes at least a temperature value T mes (n) and T mes Includes (n+1). mes (n) and T mes Further temperature values ​​besides (n+1) may be determined.

[0019] Throughout this application, variables that refer to temperatures or temperature values ​​are referred to with a capital T, while variables that refer to general points in time, lengths of time or duration are referred to with a lower case t.

[0020] When defining a general variable, the variable without the specified subscript is used, i.e. (n) or (n+1), etc. When referring to this variable in a specific context, the variable with the specified subscript is used. For example, T mes is the measured temperature value T mes This refers to the general definition of T mes (n) refers to a specific measured temperature value.

[0021] According to the invention, the temperature value T mes can be determined by measuring the temperature, which may be, for example, a single point measurement or a multi-point measurement and possible associated data processing.

[0022] Measured temperature value T mes (n) is understood as the temperature value obtained by measurement at a particular time instant t(n). Thus, the temperature value T mes (n+1) is the temperature value taken at a particular time instant t(n+1).

[0023] As used herein, the term "molten metal bath" describes a melt in a vessel. An alternative term to "molten metal bath" known to those skilled in the art is "metal melt". The molten metal of the molten metal bath is not particularly limited. According to a preferred embodiment, the molten metal is molten steel. The term molten metal bath does not exclude the presence of any solid or gaseous parts, including, for example, non-molten parts of the respective metal. The molten metal bath may be covered with a slag layer.

[0024] The temperature of the metal melt varies and usually depends on the composition of the metal and the stage of the melting process. According to a preferred embodiment, the temperature of the molten metal bath is in the range of 1500-1800 °C, more preferably in the range of 1500-1700 °C.

[0025] The molten metal bath may be contained within a vessel that includes an inlet suitable for feeding the optical core wire, which may be located in a sidewall panel or roof covering the vessel.

[0026] According to the invention, at least two temperature values ​​T mes (n) and T mes (n+1) is determined using a device comprising an optical core wire. Preferably, the optical core wire is an optical fiber surrounded laterally by a metal tube. Preferably, the optical fiber is a flexible, transparent fiber. Optical fibers are most often used as a means of transmitting light, especially in the IR wavelength range, between two ends of the fiber. Preferably, the optical fiber is made of glass or plastic, more preferably quartz glass. Preferably, the optical fiber is selected from the group consisting of graded index fiber and single mode step index fiber.

[0027] The metal tube surrounding the optical fiber may completely surround the optical fiber, or may be at least partially open so that the casing does not completely surround the optical fiber.

[0028] Preferably, the metal of the metal tube surrounding the optical fiber is iron or steel, preferably stainless steel.

[0029] In a preferred embodiment, the linear density of the optical core wire is in the range of 25 to 80 g / m, more preferably in the range of 35 to 70 g / m. Linear density is defined by mass per unit length.

[0030] Preferably, the optical core wire is laterally surrounded by at least one additional metal tube, i.e. at least two metal tubes laterally surround the optical fiber, more preferably, the optical core wire is disposed in the center of the at least one additional metal tube.

[0031] Preferably, the at least one additional metal tube is not in contact with the optical core wire. More preferably, the gap between these at least two metal tubes is at least partially filled with a material selected from the group consisting of a gaseous material or a solid material or a combination thereof. The solid material is preferably selected from the group consisting of an inorganic material, a natural polymer, a synthetic polymer and a combination thereof. The gaseous material is preferably a gas or a mixture of gases. More preferably, the gas is air or an inert gas.

[0032] According to a preferred embodiment, the optical core wire comprises a plurality of separating elements arranged in at least one metal tube, said separating elements forming at least one compartment between said separating elements. Here, the term "compartment" relates to the volume between different separating elements in the tube. The term "separating element" relates to a portion arranged in the tube that subdivides the volume in the tube. Preferably, the separating element is a disc-shaped element arranged inside the tube, said disc-shaped element comprising an opening through which the optical core wire extends and which is capable of at least partially supporting the optical core wire. The material of the separating element is preferably selected from the group consisting of silicone, preferably two-component silicone, rubber, leather, cork, metal and combinations thereof.

[0033] The optical core wire is optionally surrounded by at least one additional layer, which may or may not replace the at least one additional metal tube described above. In a preferred embodiment, the at least one additional layer includes a plurality of portions, and more preferably, the layer includes a fiber.

[0034] In a further preferred embodiment, the material of the at least one additional layer has the form of a woven, net, woven or knitted structure.

[0035] Preferably, at least one of the additional layers comprises a non-metallic material, most preferably an organic material.

[0036] It should be appreciated that the optical core wire may include any combination of the above configurations. For example, it may be advantageous for the optical core wire to be surrounded laterally by an additional layer and a second metal tube.

[0037] The device used to apply the method according to the invention further comprises a detector coupled to one end of the optical core wire and adapted to receive the optical signal, in particular in the IR wavelength range, transmitted by the optical fiber. Preferably, the detector in the context of the present invention is a pyrometer.

[0038] The optical core wire has a immersed end and an opposite end. The front end of the optical core wire is the tip of the immersed end of the optical core wire. Preferably, when the method according to the invention is applied, the optical core wire is consumed in a direction from the immersed end to the opposite end, such that after each measurement sequence, another part of the optical core wire becomes the immersed end. That is, after each measurement sequence, the front end is newly generated. The opposite end is connected to a detector and is not consumed during the measurement.

[0039] In step (a) of the method according to the invention, a model F(t) is provided which describes the temperature profile of the molten metal bath over time.

[0040] The model describing the temperature progression of a molten metal bath over time, F(t), is a model that defines the relationship between time and temperature, i.e. is adapted to predict the temperature at a specific point in time. In a typical melting process, time is directly related to the electrical energy input.

[0041] Since the model F(t) describes the temperature profile of the molten metal bath over time, its first derivative F'(t) can be interpreted as the change in temperature over time. In other words, in the case of an increasing temperature profile, the first derivative F'(t) of the model F(t) preferably represents the heating rate R of the molten metal bath over time, R = F'(t) = ΔT / Δt (where ΔT represents the temperature change and Δt represents the length of time) It can be expressed as:

[0042] Preferably, the model F(t) describes the maximum temperature of the temperature progression of the molten metal bath over time, i.e. for each temperature value a maximum heating rate R is estimated, in other words the temperature of the molten metal bath does not increase faster than this maximum heating rate at this given temperature.

[0043] In an exemplary embodiment, the first derivative F'(t) of the model F(t) describing the temperature progression of the molten metal bath over time is a linear function.

[0044] Preferably, the model F(t) describing the temperature profile of the molten metal bath over time includes a mathematical equation, characteristic curve, or other information defining the relationship between time and the temperature of the molten metal bath. This may include relationships describing the physical properties of the molten metal bath, the properties of the metallurgical equipment, and the corresponding model parameters. Preferably, the physical properties of the molten metal bath are taken into account in the model F(t).

[0045] Preferably, the model F(t) is derived by a method selected from the group of mathematical methods, analytical methods, experimental methods, and combinations thereof.

[0046] Preferably, the model F(t) describing the temperature progression of the molten metal bath over time is based on recorded measurements, i.e. data obtained during previous melting processes.

[0047] In a preferred embodiment, the estimated or measured temperature value may be the only input parameter of the model F(t) describing the temperature progression over time of the molten metal bath. In further examples, further input parameters may be utilized. Preferably, such further input parameters may be operational parameters. Operational parameters in this context are parameters that define the melting process, such as for example the electrical energy input.

[0048] In a preferred embodiment, the model F(t) describing the temperature profile of the molten metal bath over time is (i) providing a data set relating a property of the molten metal bath to recorded data of a model F(t) of the temperature progression of the molten metal bath over time; (ii) providing a molten metal bath characteristic; (iii) receiving a model F(t) describing the temperature progression of the molten metal bath over time from the provided data set relating the properties of the molten metal bath to the provided properties of the molten metal bath; The method includes:

[0049] Preferably, the data set comprises data pairs, where one particular value of one type of data is assigned to a particular value of another type of data, more preferably, the data set may comprise data pairs, where one particular value of one type of data is assigned to a model, a sequence of some steps, etc.

[0050] In step (b) of the method according to the invention, a critical temperature value T cri is defined.

[0051] "Critical temperature value T cri " should be understood as a fixed temperature value. Preferably, the critical temperature value T criis a predetermined temperature of the molten metal bath above which no further determination of the temperature value is required. Such a critical temperature may be, for example, a target temperature of the molten metal bath at which the finishing of the melting process begins. This temperature is also known as the target tapping temperature, since tapping, the last step of the metal manufacturing process, begins when the molten metal bath reaches this temperature.

[0052] In step (c) of the method according to the invention, the measured temperature value T of the molten metal bath is mes (n) is measured at time t(n).

[0053] Temperature value T mes By measuring the temperature T(n), the temperature of the molten metal bath at time t(n) is obtained. mes (n) is determined.

[0054] Temperature value T mes To measure the temperature, radiation emitted by the molten metal bath, especially in the IR wavelength range, and conveyed by the optical core wire to a detector is recorded. The intensity and / or spectral information of the radiation may be processed by a processing unit connected to the detector. The front end of the optical core wire is preferably immersed below the surface of the molten metal bath at the time the temperature is acquired.

[0055] Preferably, the measured temperature value T mes The determination of may involve the measurement of a single data point or the measurement of more than one data point, i.e., the measurement of a series of data points.

[0056] Preferably, the measured temperature value T mes is the average value of the series of data points. More preferably, the determined temperature value is derived based on application of an algorithm that processes the series of data points.

[0057] Preferably, the measured temperature value T mes is determined by application of the measurement profile MP.

[0058] Preferably, the measured temperature value T mes(n) is determined by application of a measurement profile MP(n).

[0059] A measurement profile MP is to be understood as a sequence of steps performed to obtain a value of interest, which in the context of the present invention is the temperature of the molten metal bath.

[0060] In a preferred embodiment, the measurement profile MP is (i) providing a front end of an optical core wire above a surface of a molten metal bath; (ii) at least one feed rate v fed feeding a front end of the optical core wire toward and below the surface of the molten metal bath for a time period from t0 to t2, the front end of the optical core wire being below the surface of the molten metal bath for a time period from t1 to t2; (iii) acquiring temperature information within a measurement time from t1 to t2; (iv) The front end of the optical core wire is moved at a velocity v ret to a position above the molten metal bath; Define at least one of the following:

[0061] In other words, the measurement profile MP preferably defines at least steps (i) and / or (ii) and / or (iii) and / or (iv). Preferably, the measurement profile MP defines steps (i), (ii), (iii) and (iv).

[0062] It should be understood that t1 and t2 are later than t0, and t2 is later than t1. t1 is the time when the leading end enters the molten metal bath, i.e., when the leading end is immersed below the surface of the molten metal bath. t2 is the time when the leading end subsequently retracts toward a position above the surface of the molten metal bath.

[0063] Preferably, steps (i), (ii) and (iv) are carried out in consecutive order.

[0064] Preferably, step (iii) is carried out at least partially during step (ii).

[0065] Those skilled in the art will understand that "providing a front end" and "advancing a front end" necessarily include providing and advancing an optical core wire, i.e., providing an optical core wire having a front end and moving the optical core wire with its front end.

[0066] Feed rate v fed It should be understood that V refers to the average velocity while feeding the front end toward and below the surface of the molten metal bath.

[0067] The surface of the molten metal bath may be the surface facing the surroundings of the vessel or, if a slag layer is present, the surface facing the slag layer.

[0068] In a preferred embodiment, the feed in step (ii) of the measurement profile MP is performed at least two feed rates v fed 1 and v fed 2. In addition, the feed rate v fed 1 and v fed It should be understood that 2 refers to the average speed at which the front end of the optical core wire is fed.

[0069] Preferably, the feed in step (ii) of the measurement profile MP is at a feed rate v at which the front end is fed between t0 and t1. fed 1 and the second feed rate v at which the front end is fed between t1 and t2. fed Includes 2 and.

[0070] According to a preferred embodiment, the measurement profile MP defines a further step within a quiescent time from t1 to t2, during which the feeding of the front end of the optical core wire is paused or the front end of the optical core wire is fed at a slow speed. As used herein, "pausing the feeding of the front end" means that the front end is not actively moved. In both alternatives of pausing the feeding or feeding at a slow speed, a movement of the position of the front end towards the surface of the molten metal bath is brought about due to consumption. Nevertheless, the front end is still immersed below the surface of the molten metal bath.

[0071] A low speed is preferably less than 0.2 m / s, more preferably less than 0.1 m / s.

[0072] In step (d) of the method according to the invention, the model F(t), the critical temperature value T cri , and the measured temperature value T mes Based on (n), the fitted heating rate R heat (n) is determined, and R heat (n) is R heat (n) = ΔT heat (n) / Δt It is defined as:

[0073] Fitted heating rate R heat (n) is the temperature value T until the critical temperature is reached mes (n) can be understood as the average expected heating rate. In other words, R heat (n) is the expected temperature change ΔT within a time period Δt heat (n).

[0074] The model F(t) is the critical temperature value T cri The time instant t associated with cri It should be understood that the above may be applied so that the following can be determined:

[0075] According to a preferred embodiment, the fitted heating rate R heat(n) is determined based on a linear fitting of the model F(t). More preferably, the fitted heating rate R heat (n) is the time t cri is determined based on a linear fitting of a model F(t) between

[0076] Preferably, the fitted heating rate R heat (n) is the time t cri and is determined based on the first derivative of the model F(t) with respect to time t(n). More preferably, the fitted heating rate R heat (n) is the time t cri and is determined by the average of the first derivatives of the model F(t) for time instant t(n).

[0077] According to a preferred embodiment, the fitted heating rate R heat (n) is determined based on a model of the heating rate of the molten metal bath, R(T), which is cri , time t(n), and the measured temperature value T mes (n) is based on the first derivative of the model F(t).

[0078] In step (e) of the method according to the invention, a critical temperature value T cri and the measured temperature value T mes (n) and the fitted heating rate R heat (n) and time t cal (n+1) is calculated, ΔT(n)=T cri -T mes (n) and t cal (n+1)=t(n)+(ΔT(n) / R heat (n) It is.

[0079] Step (e) is a step of measuring the temperature profile of the molten metal bath based on the fitted heating rate R determined in step (d). heat (n) if the critical temperature value T criAt a future time t cal This yields a prediction of (n+1).

[0080] Preferably, the fitted heating rate R heat (n) is greater than the actual heating rate of the molten metal bath. Therefore, at a future time t cal At (n+1), the temperature of the molten metal bath is at the critical temperature T Cri will be lower than

[0081] In step (f) of the method according to the invention, the measured temperature value T of the molten metal bath is mes (n+1) is measured at time t(n+1).

[0082] Temperature value T mes By measuring the temperature T of the molten metal bath at time t(n+1), mes (n+1) is determined.

[0083] Preferably, the measured temperature value T mes (n+1) is determined by application of the measurement profile MP(n+1).

[0084] Preferably, the feed rate v of the measurement profile MP(n+1) fed The larger the measured temperature value T mes (n) becomes higher.

[0085] Preferably, the shorter the time length from t1 to t2 in the measurement profile MP(n+1), the shorter the measured temperature value T mes (n) becomes higher.

[0086] Preferably, steps (c) to (f) are carried out in consecutive order.

[0087] Preferably, step (a) is carried out before step (c), more preferably before step (d), and most preferably before step (e).

[0088] Preferably, the method comprises the following sequence: (a)-(b)-(c)-(d)-(e)-(f), (b)-(a)-(c)-(d)-(e)-(f), (b)-(c)-(a)-(d)-(e)-(f), or (b)-(c)-(d)-(a)-(e)-(f) It is executed in one of

[0089] Preferably, step (b) is carried out before step (a), more preferably before step (c), and most preferably before step (d).

[0090] Preferably, the method comprises the following sequence: (b)-(a)-(c)-(d)-(e)-(f), (a)-(b)-(c)-(d)-(e)-(f), or (a)-(c)-(b)-(d)-(e)-(f) It is executed in one of

[0091] Preferably, the method is carried out a number of times. More preferably, the method comprises the steps of: cri This is carried out multiple times until it reaches

[0092] Preferably, the method comprises the following steps (g) to (i): (g) Model F(t), critical temperature value T cri , and the measured temperature value T mes Based on (n+1), the fitted heating rate R heat (n+1), heat (n+1) is R heat (n+1)=ΔT heat (n+1) / Δt; (h) Critical temperature value T cri and the temperature value T mes (n) and the fitted heating rate R heat (n) and time t cal (n+2), ΔT(n+1)=Tcri -T mes (n+1) and t cal (n+2)=t(n+1)+(ΔT(n+1) / R heat (n+1) The process and (i) Time t cal (n+2) is the measured temperature value T of the molten metal bath mes measuring (n+2); Includes.

[0093] Preferably, the fitted heating rate R heat (n+1) is the fitted heating rate R heat (n), i.e., the temperature difference ΔT heat (n+1) is the temperature difference ΔT heat Greater than (n).

[0094] Preferably, steps (g) to (i) are carried out in consecutive order.

[0095] Preferably, steps (g) to (i) are carried out after steps (a) to (f).

[0096] Preferably, the method comprises the following sequence: (a)-(b)-(c)-(d)-(e)-(f)-(g)-(h)-(i), (b)-(a)-(c)-(d)-(e)-(f) (g)-(h)-(i), (b)-(c)-(a)-(d)-(e)-(f) (g)-(h)-(i), or (b)-(c)-(d)-(a)-(e)-(f) (g)-(h)-(i) It is executed in one of

[0097] The present invention further provides a method for determining a temperature of a molten metal bath by a series of at least two temperature values ​​T mes (n) and T mes A system for determining (n+1) is provided, comprising a device and a module, the module adapted to interact with the device.

[0098] Preferably, the system comprises a method according to the invention, comprising: (a) providing a model F(t) describing the temperature profile of a molten metal bath over time; (b) Critical temperature value T cri Defining (c) The measured temperature value T of the molten metal bath at time t(n) mes (n) measuring the (d) Model F(t), critical temperature value T cri , and the measured temperature value T mes Based on (n), the fitted heating rate R heat (n), wherein R heat (n) is R heat (n) = ΔT heat (n) / Δt and (e) Critical temperature value T cri and the temperature value T mes (n) and the fitted heating rate R heat (n) and time t cal (n+1), ΔT(n)=T cri -T mes (n) and t cal (n+1)=t(n)+(ΔT(n) / R heat (n) The process and (f) Time t cal The measured temperature value T of the molten metal bath at (n+1) mes (n+1); The device is configured to perform a method including:

[0099] For preferred embodiments of the method of the present invention, please refer to the above preferred embodiments.

[0100] The system according to the invention comprises an apparatus, the apparatus comprising an optical core wire and a detector, for preferred embodiments of the optical core wire and the detector please refer to the preferred embodiments above.

[0101] The system according to the present invention includes a module, which includes a storage unit, a processing unit, and a control unit.

[0102] Preferably, the storage unit, the processing unit and the control unit are arranged to interact with each other.

[0103] According to the invention, the storage unit of the module is (a1) a memory element for providing a model F(t) describing the temperature profile of a molten metal bath over time; (a2) Critical temperature value T cri A storage element for defining Includes.

[0104] According to the invention, the processing unit of the module (b1) Model F(t), critical temperature value T cri , and the measured temperature value T mes Based on the fitted heating rate R heat A processing element for determining R heat teeth, R heat = ΔT heat / Δt a processing element defined as (b2) Critical temperature value T cri and the measured temperature value T mes and the temperature difference ΔT and the fitted heating rate R heat Based on this, at time t cal A processing element for calculating ΔT=T cri -T mes and t cal =t+(ΔT / R heat ), A processing element; Includes.

[0105] In a preferred embodiment, the processing unit is configured to process information stored in the storage unit.

[0106] According to the invention, the control unit of the module (c1) Temperature value of the molten metal bath T mes Includes a control element for measuring

[0107] In a preferred embodiment, the control unit is adapted to control the device.

[0108] In a preferred embodiment, the system comprises a feeding means, which in the context of the present invention may be understood as a means allowing the feeding of the optical core wire into the molten metal bath. Such a means may be selected from the group consisting of a feeder, a feed control device, a straightener and a guide tube.

[0109] According to a preferred embodiment, the system further comprises a coil corresponding to the length of the optical core wire. [Brief description of the drawings]

[0110] The concepts underlying the invention are explained in more detail below with reference to the embodiments shown in the drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0111] [Figure 1] 1A-1D are schematic cross-sectional views of various designs of optical core wires. [Diagram 2] FIG. 1 is a schematic diagram of an exemplary installation 6 having a molten metal bath 7 whose temperature is to be determined. [Diagram 3] 13 is a position-time graph showing the immersion of the front end of the optical core wire during application of a representative measurement profile. [Figure 4] 13 is a position-time graph showing immersion of the front end of the optical core wire during application of another exemplary measurement profile. [Diagram 5]1 is a schematic diagram of a system according to one embodiment of the present invention. [Figure 6] FIG. 2 is a schematic diagram of a module according to one embodiment of the present invention. [Figure 7] 4 is a graph illustrating a method according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0112]

[0011] Figure 1 is a schematic cross-sectional view of various designs of optical core wires according to exemplary embodiments of the present invention. Figure 1A shows an optical core wire 1' that includes an optical fiber 2' surrounded by a metal tube 3'.

[0113] FIG. 1B shows an optical core wire 1'' comprising an optical fiber 2'' surrounded by a metal tube 3''. A second metal tube 4'' further surrounds the metal tube 3''. The gap 5'' between the two metal tubes is not filled with a solid material, i.e., the gap may contain a gas or a gas mixture.

[0114] FIG. 1C shows an optical core wire 1''' comprising an optical fiber 2''' surrounded by a metal tube 3''' and a second metal tube 4'''. The gap 5''' between the two metal tubes is filled with a filling material, e.g., an organic material or a fiber from E-glass.

[0115] FIG. 2 is a schematic diagram of an exemplary installation 6 having a molten metal bath 7 whose temperature is to be determined.

[0116] The installation 6 comprises an optical core wire 1, which is at least partially placed on a coil 8 and at least partially unwound from the coil 8 for performing measurements. One end of the optical core wire 9 is connected to a detector 10, which can be connected to a computer system (not shown) for processing data acquired with the optical core wire 1 and the detector 10. The molten metal bath 7 is contained in a vessel 11, which can be an electric arc furnace, a ladle, a tundish or any vessel known to a person skilled in the art for molten metal processing. The optical core wire 1 is introduced by a feeder 12 through a guide tube 13 into the vessel 11, which has an inlet 14. The illustrated configuration is used as an example, a roof with a respective inlet is not a prerequisite for the invention.

[0117] The illustrated configuration has a front end 15 which is connected to a molten metal bath MB S 1 shows an exemplary measurement position of the optical core wire 1 immersed below the surface of the molten metal bath MB S The immersion angle of the optical core wire 1 with respect to the surface of the metallurgical equipment is 90°. However, this angle can be varied depending on the construction details of the metallurgical equipment.

[0118] The temperature of the portion of the optical core wire 1 that extends from the coil 8 to the entrance 14 of the vessel may be considered low and may range from room temperature to 100° C. As it passes through the entrance 14 towards the molten metal bath 7 it first encounters a high temperature atmosphere of up to 1700° C. or more, then a slag layer 17, and then the molten metal bath 7. The entrance 14 to the vessel may be provided with a blowing lance 18 to prevent ingress of metal and slag into the guide tube 13.

[0119] To obtain a temperature measurement, the optical core wire 1 is fed with its front end at the immersion end 15 towards the molten metal bath 7 to the required immersion depth. To obtain a reliable temperature measurement, it may be desirable to measure at an approximately constant immersion depth in the molten metal bath. A suitable feeding system 12 precisely controls the feeding speed of the optical core wire 1.

[0120] After the measurement sequence, the portion 19 of the optical core wire immersed in the molten metal bath is melted and therefore consumed. The length of this portion is L C After the measurement is made, the portion of the optical core wire 20 that is located in the high temperature atmosphere and extends through the slag layer may be sent back towards the coil 8 and reused for the next measurement.

[0121] Because the temperature of the molten metal bath 7 is a critical process parameter, detailed knowledge of its progression during the metal production process is desired and the process involves a series of measurements. In a typical EAF process, the temperature of the molten metal increases more slowly at lower temperatures than at higher temperatures.

[0122] In the lower temperature range, the molten metal bath still contains unmelted parts, but in the higher temperature range, the molten metal contained in the metal bath is homogenous, so all of the energy input is directed to heating the material and is not wasted by melting the solid parts.

[0123] Temperature measurements are usually taken after reaching a flat bath, which for most steels is typically above a temperature value of 1500°C. Heating rates at this temperature are typically of the order of 10°C / min. Within the temperature range of typical target tapping temperatures, typically 1650°C, heating rates can be increased to 80°C / min, depending on the energy input.

[0124] FIG. 3 is a position-time graph showing the immersion of the front end of the optical core wire during application of a typical measurement profile. The x-axis shows time and the y-axis shows the position of the front end. Molten metal bath MB SThe position of the surface of is shown for orientation. Prior to the start of the measurement, i.e. before t0, the leading end is placed at the starting point. This may be inside the metallurgical vessel or may be close to the entrance, i.e. near the point where the optical core wire enters the vessel. The optical core wire is fed at a feed rate towards and into the molten metal bath for a time period from t0 to t2. This length of time is typically in the range of a few seconds. The leading end of the optical core wire enters the molten metal bath at time t1, i.e. t1 is the time when the leading end is immersed below the surface of the molten metal bath. In the illustrated graph, a single feed rate is applied, but the feeding may include several stages with different feed rates. Phases without feeding, i.e. pause stages, may be included during the performance of the measurement, as shown in the graph shown in FIG. 4, which represents another preferred embodiment. Temperature measurements are taken during the measurement time from t1 to t2. To obtain reliable measurements, the leading end must be immersed below the surface of the molten metal bath. Temperature values ​​obtained during the initial stages of feeding often do not represent the bulk temperature of the molten metal bath. After t2, the optical core wire is retracted from the molten metal bath and returned to a position above the surface. Ideally, the molten metal bath L C The portion of the optical core wire that is immersed below the surface of is consumed by t2.

[0125] The time required for the immersed portion of the optical core wire to be completely consumed to the surface of the molten metal bath depends on the temperature of the molten metal and the properties of the optical core wire. The properties of the optical core wire that affect the melting or consumption behavior mentioned above include its design and the material from which it is made. For example, a metal tube with a thicker wall thickness will melt slower than a metal tube of the same material with a thinner wall thickness. In either case, the measurement is always related to the consumption of a specific portion of the optical core wire. Therefore, by minimizing the number of measurements, the amount of consumption of the optical core wire is minimized.

[0126] Fig. 5 is a schematic diagram of a system 30 according to an embodiment of the present invention, configured to carry out the method of the present invention. Thus, the system 30 is configured to provide a model describing the temperature progression of the molten metal bath over time. The system 30 is further configured to define a critical temperature, e.g. a target temperature of the molten metal bath. Furthermore, the system 30 is configured to determine a heating rate based on the input of the critical temperature, the measured temperature and the model describing the time-dependent temperature progression of the molten metal bath. The system 30 is further adapted to calculate a time point based on the first time point, the determined heating rate and the temperature difference. Furthermore, the system 30 is configured to measure a temperature value.

[0127] The system comprises an apparatus 40, which comprises an optical core wire and a detector. Furthermore, the system comprises a module 50. Figure 6 shows a schematic diagram of the module 50 in more detail. The module 50 comprises a storage unit 60, a processing unit 70 and a control unit 80.

[0128] In the following, exemplary conditions according to the invention are given. EXAMPLES

[0129] The apparatus containing the optical core wire was placed in a typical electric arc furnace (EAF) setup according to Figure 2. The optical core wire comprised a graded-index fiber with a core diameter of 50 μm and a stainless steel tube with an outer diameter of 1.3 mm. The metal-tubed fiber was embedded in a stainless steel tube with an outer diameter of 6 mm and a wall thickness of 0.3 mm.

[0130] The scrap was loaded into the EAF and the melting process was started. Cri ) was targeted. Figure 7 shows the expected temperature evolution over time for a particular metallurgical installation with the applied process parameters. The underlying model is based on the maximum expected increase in temperature recorded from previous processes. Based on the consumed accumulated power of the EAF, a first measurement was started, with a temperature value of 1520 °C (T at the time designated as t(n) in Figure 7). mesThe temperature difference ΔT(n) of 130°C from the measured temperature to the critical temperature and the expected time (t Cri Based on Δt(n) up to 32.5 °C / min average heating rate R heat (n) was expected. Therefore, the next measurement time point t(n+1) was set to 4 minutes after the first measurement.

[0131] In the second measurement, the temperature value was 1600°C (T mes (n+1)) was determined. According to the temperature difference of 50° C. and the expected time of reaching the target tapping temperature, 43 seconds after the second measurement, the third measurement was scheduled 43 seconds after this second measurement, i.e. the expected heating rate was 70° C. / min. [Explanation of symbols]

[0132] 1, 1', 1'', 1''' Optical Core Wire 2', 2'', 2''' optical fiber 3', 3'', 3''' metal tube 4'', 4''' 2nd metal tube 5'', 5'''' Air gap between metal tubes 6 Equipment 7 Molten metal bath 8 Coils 9 Opposite end (the end of the core wire connected to the detector) 10. Detector 11 Container; metallurgical container 12 Feeder 13 Guide tube 14 Entrance 15 Front end of optical core wire MBS Molten Metal Bath Surface 17 Slag layer 18 Blowing Lance 19 The portion of the core wire immersed in the molten metal bath LC Length of optical core wire immersed in molten metal bath 20 Part of the core wire exposed to high temperature atmosphere and slag 30 Systems 40 equipment 50 Modules 60 Storage Unit 70 Processing Unit 80 Control Unit

Claims

1. A series of at least two temperature values ​​T of the molten metal bath is obtained using an apparatus including an optical core wire and a detector. mes (n) and T mes A method for determining (n+1), comprising the steps of: (a) providing a model F(t) describing the temperature profile of the molten metal bath over time; (b) Critical temperature value T cri Defining (c) the measured temperature value T of the molten metal bath at time t(n) mes (n); and (d) the model F(t), the critical temperature value T cri , and the measured temperature value T mes Based on (n), the fitted heating rate R heat (n), comprising determining R heat (n) is R heat (n)=ΔT heat (n) / Δt The process defined as: ΔT heat (n) represents the temperature change, Δt represents the length of time, and R heat (n) is the expected temperature change ΔT within a time period Δt heat (n), the fitted heating rate R heat (n) being the heating rate expected, on average, from the measured temperature values ​​T mes (n) until the critical temperature value T cri is reached; (e) the critical temperature value T cri and the measured temperature value T mes (n) and the temperature difference ΔT(n) and the fitted heating rate R heat (n) at time t cal (n+1), ΔT(n)=T cri -T mes (n) and t cal (n+1)=t(n)+(ΔT(n) / R heat (n) The process and (f) Said time t cal (n+1) is the measured temperature value T of the molten metal bath. mes measuring (n+1); A method comprising:

2. The method comprises: (g) the model F(t), the critical temperature value T cri , and the measured temperature value T mes Based on (n+1), the fitted heating rate R heat (n+1), comprising: heat (n+1) is R heat (n+1)=ΔT heat (n+1) / Δt; (h) the critical temperature value T cri and the measured temperature value T mes (n) and the fitted heating rate R heat (n) at time t cal (n+2), ΔT(n+1)=T cri -T mes (n+1) and t cal (n+2)=t(n+1)+(ΔT(n+1) / R heat (n+1) The process and (i) Said time t cal (n+2) is the measured temperature value T of the molten metal bath. mes measuring (n+2); The method of claim 1 , comprising:

3. The fitted heating rate R heat (n+1) is the fitted heating rate R heat The method of claim 2 , wherein the n is greater than (n).

4. The method according to any one of the preceding claims, wherein the model F(t) describes the maximum temperature of the temperature profile of the molten metal bath over time.

5. The method according to any one of the preceding claims, wherein the first derivative of the model F(t) describing the temperature progression over time of the molten metal bath is a linear function.

6. The method according to any one of the preceding claims, wherein the model F(t) describing the temperature progression over time of the molten metal bath is based on previous measurements.

7. The method according to any one of the preceding claims, wherein the model F(t) describing the temperature progression over time of the molten metal bath is based on operational parameters.

8. The fitted heating rate R heat The method of any one of claims 1 to 7, wherein (n) is determined based on a linear fitting of the model F(t).

9. The fitted heating rate R heat (n) is the time t cri and is determined based on a first derivative of the model F(t) with respect to the time t(n), Said time t cri is the critical temperature value T cri The method according to any one of claims 1 to 8, wherein said model F(t) is determined by applying said model F(t) in relation to

10. The model F(t) describing the temperature profile of the molten metal bath over time is (i) providing a data set relating a property of the molten metal bath to recorded data relating to said temperature progression of the molten metal bath over time; (ii) providing characteristics of the molten metal bath; (iii) receiving a model F(t) describing the temperature progression of the molten metal bath over time from the provided data set that correlates properties of the molten metal bath to the provided properties of the molten metal bath; The method according to any one of claims 1 to 9, wherein the method comprises:

11. Measured temperature value T mes The method according to any one of claims 1 to 10, wherein is determined by application of a measurement profile MP.

12. The measurement profile MP is (i) providing the optical core wire with its front end above the surface of the molten metal bath; (ii) at least one feed rate v fed feeding the front end of the optical core wire towards the molten metal bath and below the surface of the molten metal bath for a time from t0 to t2, wherein the front end of the optical core wire is below the surface of the molten metal bath for a time from t1 to t2; (iii) acquiring temperature information within a measurement time from t1 to t2; (iv) rotating the optical core wire at a velocity v ret to a position above the molten metal bath; The method of claim 11 , further comprising defining at least one of:

13. 13. The method of claim 12, wherein the measurement profile MP defines a further step within a quiescent time from t1 to t2, during which the feeding of the front end of the optical core wire is paused or the front end of the optical core wire is fed at a slow speed.

14. In step (ii), feeding the front end of the optical core wire includes feeding the front end of the optical core wire at at least two feed rates v fed 1 and v fed 14. The method according to claim 12 or 13, wherein said method is defined by:

15. A series of at least two temperature values ​​T of the molten metal bath comprising the device and the module. mes (n) and T mes a system for determining (n+1), the module adapted to interact with the device, the device including an optical core wire and a detector; The module includes a storage unit, a processing unit, and a control unit; The storage unit includes: (a1) a memory element for providing a model F(t) describing the temperature profile of the molten metal bath over time; (a2) Critical temperature value T cri A storage element for defining Including, The processing unit includes: (b1) Model F(t), critical temperature value T cri , and the measured temperature value T mes Based on the fitted heating rate R heat A processing element for determining R heat teeth, R heat =ΔT heat / Δt is defined as ΔT heat (n) represents the temperature change, Δt represents the length of time, and R heat (n) is the expected temperature change ΔT within a time period Δt heat (n), a processing element, wherein the fitted heating rate R heat (n) is the heating rate expected on average from the measured temperature values ​​T mes (n) until the critical temperature value T cri is reached; (b2) Critical temperature value T cri and the measured temperature value T mes and the temperature difference ΔT between the fitted heating rate R heat Based on this, at time t cal A processing element for calculating ΔT = T cri -T mes and t cal = t + (ΔT / R heat ) A processing element; Including, The control unit (c1) the temperature value T of the molten metal bath mes [0033] Including a control element for measuring system.

Images