JP2012251884A - Boundary position detection method, boundary position detection system and data measurement probe used in boundary position detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of surely measuring a molten steel temperature, a coagulation temperature and a sample property, etc., for instance by accurately and surely detecting respective boundary position and thus accurately controlling an immersion depth to a molten metal layer.SOLUTION: A boundary position detection system comprises: a metal electrode 20 provided movably over a molten metal layer L, a slug layer B and an atmospheric layer A; and a computer 5 that functions as arithmetic means for obtaining a frequency distribution by frequency-analyzing electrode voltage signals in a prescribed cycle, and detection means for detecting positions of respective boundaries Ls and Bs by a change of intensity of a commercial power source frequency (for instance, in Japan, eastern Japan region 50 Hz/western Japan region 60 Hz) of an installation region of a molten metal container C in each frequency distribution obtained by the arithmetic means.

Description

  The present invention relates to a technique for detecting each boundary position of a molten metal layer, a slag layer, and an atmospheric layer in a molten metal container such as a converter.

  In order to measure the temperature, solidification temperature, sample properties, etc. of the molten metal or slag layer in a molten metal container such as a converter, a data measurement probe equipped with various sensors and sample sampling ports is used. In order to perform various measurements and sample collection with this probe with high accuracy, it is necessary to control the measurement position, that is, the depth at which the probe is immersed in the molten metal layer or slag layer to an optimum depth. For this purpose, it is necessary to accurately grasp the surface level of the molten metal layer or the slag layer.

  As a method for measuring the surface level of these molten metal layers and slag layers, various methods have been conventionally proposed, for example, a coil-type level meter is provided to measure the surface level of the molten metal layer in a non-contact manner, It is known that the signal voltage of the electrode varies at the boundary between the molten metal layer and the slag layer and the boundary between the slag layer and the atmospheric layer to detect the boundary position (surface level) (for example, Patent Documents 1 to 3). 4). However, the method using a coil level meter lacks accuracy, and the method using the voltage change of the electrode may cause the slag to be close to molten metal depending on the steel type and blowing method, and the voltage change may not occur. There was a problem of lacking.

Japanese Patent Laid-Open No. 2004-125 566 JP 2002-356709 A JP-A-9-113333 Japanese Patent Laid-Open No. 10-122934

  Therefore, in view of the above-described situation, the present invention intends to solve each boundary position more accurately and reliably, thereby more accurately controlling the immersion depth in the molten metal layer, For example, it provides a technique capable of more reliably measuring the molten steel temperature, solidification temperature, sample properties, and the like.

  A first aspect of the present invention is a boundary position detection method for detecting a boundary between a molten metal layer in a molten metal container and a slag layer floating on the molten metal layer, and a boundary position between the slag layer and an atmospheric layer thereon. The metal electrode is moved across the molten metal layer, the slag layer, and the atmospheric layer, and the frequency distribution of the electrode voltage signal is obtained by frequency analysis calculation at a predetermined period during the movement, and the frequency distribution The boundary position detection method is characterized in that the position of each boundary is detected by a change in the intensity of the commercial power supply frequency in the area where the molten metal container is installed.

  The second of the present invention is a boundary position detection method for detecting the boundary between the molten metal layer in the molten metal container and the slag layer floating thereon, and the position of the boundary between the slag layer and the atmospheric layer above the boundary. The metal electrode is moved across the molten metal layer, the slag layer, and the atmospheric layer, and a signal having a specific frequency that is the same as or different from a commercial power supply frequency in an area where the molten metal container is installed is applied. Boundary characterized in that a frequency distribution of an electrode voltage signal is obtained by frequency analysis calculation at a predetermined period during the movement, and a position of each boundary is detected by a change in intensity of the specific frequency in the frequency distribution. A position detection method is provided.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the tip of the data measurement probe that measures various data such as temperature / oxygen concentration of one or both of the molten metal and the slag layer in the metal electrode. And detecting the position of each boundary in the process of lowering the probe in the molten metal container and immersing it in the molten metal, before measuring various data in the molten metal or slag layer, This is a boundary position detection method that makes it possible to control the position of the probe based on information.

  4th of this invention is a boundary position detection system which each detects the position of the boundary of the molten metal layer in a molten metal container, and the slag layer which floats on it, and the boundary of this slag layer and the air layer on it. A metal electrode movably provided over the molten metal layer, the slag layer, and the atmospheric layer, a computing means for frequency analysis of the electrode voltage signal in a predetermined cycle to obtain a frequency distribution, and the computer A boundary position detection system comprising: a detection means for detecting the position of each boundary according to a change in the intensity of a commercial power supply frequency in an area where the molten metal container is installed in each frequency distribution. provide.

  5th of this invention is a boundary position detection system which each detects the position of the boundary of the molten metal layer in a molten metal container, and the slag layer which floats on it, and the boundary of this slag layer and the atmospheric layer on it. A metal electrode that is movably provided across the molten metal layer, the slag layer, and the atmospheric layer, and a signal having a specific frequency that is the same as or different from a commercial power supply frequency in an area where the molten metal container is installed. And a signal applying means for calculating the frequency distribution by analyzing the frequency of the electrode voltage signal in a predetermined cycle by the computer, and the computer also determines the position of each boundary by a change in the intensity of the specific frequency in each frequency distribution. Provided is a boundary position detection system characterized by comprising detection means for detecting.

  According to a sixth aspect of the present invention, in the fourth or fifth aspect, the tip of the data measurement probe in which the metal electrode measures various data such as temperature / oxygen concentration of one or both of the molten metal and the slag layer. And detecting the position of each boundary in the process of lowering the probe in the molten metal container and immersing it in the molten metal, before measuring various data in the molten metal or slag layer, the detected position This is a boundary position detection system that makes it possible to control the position of the probe based on the above information.

  7th of this invention is a probe used for said boundary position detection system, and measures various data, such as temperature / oxygen concentration of one or both of the said molten metal and a slag layer, Comprising: The said metal electrode is made into a front-end | tip part. A data measurement probe is provided.

  According to the first invention or the fourth invention, the frequency distribution of the electrode voltage is determined in a predetermined manner without lacking in accuracy as in the case of the non-contact coil type level meter and capturing the change of the electrode voltage itself. Therefore, even if the electrode voltage is affected by the slag properties, the change in the strength of the commercial power supply frequency in the frequency distribution is more accurate. It is possible to provide a detection method or a detection system with high accuracy and high reliability that can reliably detect each boundary position without much influence. Moreover, by this, the measurement of molten steel temperature, solidification temperature, sample property, etc. can be more reliably performed by controlling the immersion depth to a molten metal layer more correctly.

  According to the second or fifth invention, as in the first invention, a highly accurate and reliable detection method can be provided, and the immersion depth in the molten metal layer can be controlled more accurately. As a result, measurement of molten steel temperature, solidification temperature, sample properties, etc. can be performed more reliably, and even when the attenuation characteristics due to noise of the commercial power supply frequency are reduced due to the installation location and slag properties, it is applied. By capturing the intensity change at the specific frequency, the boundary position can be detected accurately and reliably. In particular, if this specific frequency is the same as the commercial power supply frequency in the region, a signal applied to the commercial power supply frequency noise is added, and a clearer attenuation characteristic can be obtained, and the boundary position can be reliably detected. In addition, in the case of different frequencies, the boundary position can be reliably detected from the clear attenuation characteristic due to the applied specific frequency, and the boundary position can also be detected from the attenuation characteristic of the commercial power supply frequency to double check.

  According to the third invention or the sixth invention, based on the detection signal of the surface of the molten metal layer output from the detection means during the probe immersion process, the probe is inserted into the molten metal layer in the subsequent immersion process. Since the immersion depth is controlled, the immersion depth is controlled in real time based on the level measurement in the same immersion process with the same charge, and there is no deviation of the immersion depth due to fluctuations in the amount of molten metal as in the past. Therefore, the immersion depth can be controlled more accurately, and the measurement of molten steel temperature, solidification temperature, sample properties, etc. can be performed more reliably.

  According to the seventh invention, as described above, the immersion depth can be more accurately and reliably controlled using such a data measurement probe, and the measurement of the molten steel temperature, the solidification temperature, the sample properties, etc. can be performed more reliably. Can be done.

The schematic diagram which shows the whole structure of the boundary position detection system which concerns on typical embodiment of this invention. (A), (b) is explanatory drawing which shows the principal part of the data measurement probe similarly used for a boundary position detection system. The block diagram which shows the structure of the computer similarly used for a boundary position detection system. It is explanatory drawing which shows the circuit characteristic between electrodes-G (earth), (a) is an equivalent circuit in an atmospheric layer, (b) is an equivalent circuit in a slag layer, (c) is an equivalent circuit in a molten metal layer. Explanatory drawing which shows the change of frequency distribution (FFT spectrum pattern) when a metal electrode is immersed in a slag layer from an atmospheric layer. Explanatory drawing which shows the change of frequency distribution (FFT spectrum pattern) when a metal electrode moves to a molten metal layer (molten steel layer) from a slag layer. The graph which shows the change of an electrode voltage and 60Hz spectral intensity (frequency peak). Explanatory drawing which shows the example of control of the downward movement of a data measurement probe by an operation control process part. Explanatory drawing which shows the example of control of the oxygen flow rate and height of a main lance. Explanatory drawing which shows a mode that the oxygen potential in slag is calculated | required. The schematic diagram which shows the modification which provided the oscillator which applies a specific frequency. Explanatory drawing which similarly shows the change of the frequency distribution (FFT spectrum pattern) in a modification.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the boundary position detection system S of the present invention includes a position (a molten metal layer level) of a boundary Ls between a molten metal layer L and a slag layer B floating thereon in the molten metal container C, and A metal electrode that detects the position (slag layer level) of the boundary Bs between the slag layer B and the atmospheric layer A thereon, and is provided so as to be movable over the molten metal layer L, the slag layer B, and the atmospheric layer A 20, calculation means for frequency analysis of the electrode voltage signal at a predetermined period to obtain a frequency distribution, and commercial power supply frequency (for example, eastern Japan in Japan) in the area where the molten metal container C is installed in each frequency distribution obtained by the calculation means And a computer 5 functioning as detection means for detecting the positions of the boundaries Ls and Bs according to a change in intensity in the region 50 Hz / Western Japan region 60 Hz.

  The molten metal container C can be widely applied to a melting furnace (a ladle or a converter or the like) that holds molten steel, hot metal, or the like as a molten metal, but can also be applied to other molten metal containers. In the following embodiment, although the example applied to the blowing process in a converter is shown, it is not limited to this at all. In this example, the metal electrode 20 is provided at the tip 1a of the data measuring probe 1 that moves up and down with the sub lance in the converter C and is immersed in molten metal to collect various data. In the figure, reference numeral 3 is a sub lance for supporting the probe 1, 4 is a sub lance lifting device, 5 is a computer, and 6 is a main lance that blows out oxygen from the tip to the molten metal (molten steel) below.

  As shown in FIG. 2 (a), the data measurement probe 1 is provided with an oxygen sensor 11, a correction electrode 12, and a temperature sensor 13 covered with a protective cap 10 at the tip 1a, and a paper exterior on the body. A sample collection port 14 closed with a member is provided. Further, the metal electrode 20 is provided on the outer peripheral surface of the protective cap 10 in an externally exposed state, and the lead wire of the metal electrode 20 is the same as the wiring of the oxygen sensor 11, the correction electrode 12, and the temperature sensor 13. It extends to the base end side along the probe 1, extends further to the base end side through the sublance 3, and is connected to the + input terminal of the operational amplifier 7 shown in FIG. Here, it is preferable to use the wiring of the correction electrode 12 as shown in FIG. 2B, for example, instead of providing the lead wire of the metal electrode 20 independently of the wiring of the sensor or the like. In this way, the electrode voltage of the metal electrode 20 can be taken out efficiently without increasing the wiring inside the data measurement probe, and the degree of freedom in structural design is improved. This is because when the data measuring probe 1 is immersed in the molten metal, the wiring of the correction electrode 12 does not function due to the presence of the protective cap 10, and therefore there is no problem even if it is used as the wiring of the correction electrode 12. This is because it can be used. Reference numeral 8 in the figure denotes an operational amplifier for an oxygen sensor.

  This data measurement probe 1 is the same as the conventional data measurement probe except for the metal electrode 20 and its wiring, and as shown in FIG. 1, a sub lance 3 arranged in the vertical direction above the converter C is provided. The probe 1 can be moved into the converter C by attaching the data measurement probe 1 to the lower end portion and moving the sublance 3 together with the probe 1 by the sublance lifting device 4. Specifically, it is immersed in the molten metal layer L through the slag layer B floating on the surface of the molten metal from the atmosphere layer A, stopped at a predetermined depth for several seconds, and the protective cap 10 and the exterior member melt and disappear. After measurement by various sensors and sample collection, the molten metal layer L is pulled up to the atmosphere layer A through the slag layer B.

  The converter C is formed by stacking refractory bricks inside a metal container, and the container itself is grounded to the ground and connected to the negative input terminal of the operational amplifier 7. The converter alone does not have conductivity, but by containing molten steel in the converter, metal adheres to the inner surface of the converter, or the temperature of the refractory brick rises and becomes conductive, and the inner surface of the converter And the ground G have conductivity. That is, it is equivalent to the converter being grounded to the ground G. The sublance lifting / lowering device 4 is configured using a servo motor, a pulse motor, or the like, and is controlled by a computer 5. Further, a rotary encoder is attached to the sublance elevating device 4, and a signal is input to the computer 5 as data relating to the amount of elevation of the sublance 3.

  As shown in FIG. 3, the computer 5 includes a processing device 50 and a storage unit 51, and the operational amplifier 7 and the sublance lifting / lowering device 4 are connected to the processing device 50. The processing device 50 is mainly configured by a CPU such as a microprocessor, and has a storage unit including a RAM and a ROM (not shown), and stores programs and processing data for defining procedures of various processing operations. The computer 5 may be composed of a plurality of computers other than those composed of a single computer.

  The processing device 50 functionally analyzes a voltage data storage processing unit 50a that stores electrode voltage signal data (voltage data) input through the operational amplifier 7 in the storage unit 51, and frequency-analyzes the voltage data at a predetermined cycle. A calculation processing unit 50b for determining a frequency distribution, a boundary detection processing unit 50c for determining the positions of the boundaries Ls and Bs based on a change in the intensity of the commercial power supply frequency in the region where the molten metal container C is installed in each frequency distribution, An operation control processing unit 50d for controlling the lifting operation of the lifting device 4 and at least a lifting data storage processing unit 50e for storing the sublance lifting amount data input from the rotary encoder of the sublance lifting device 4 in the storage means 51 are provided. These functions are realized by the above program.

  The storage unit 51 includes a hard disk or the like inside or outside the computer 5, and includes a voltage data storage unit 51a that stores the voltage data, a frequency distribution data storage unit 51b that stores the frequency distribution data calculated by the arithmetic processing unit 50b, It includes at least an ascent / descent data storage unit 51c for storing the sublance ascent / descent data. These storage means 51 include, of course, a case where data is stored in a temporary storage area in addition to the hard disk and the like. In the example in which the boundary is grasped and controlled in real time when the probe descends as in this example, it is preferable that each of the storage units 51a, 51b, and 51c is configured by a high-speed memory to correspond to high-speed computation.

  The arithmetic processing unit 50b stores the voltage data storage unit 51a in the voltage data storage unit 51a while the data measurement probe 1 at the lower end of the sublance 3 is lowered by the sublance lifting device 4 and is immersed in the slag layer B and the molten metal layer L from the atmospheric layer A. The stored voltage data is taken out at a predetermined short cycle, and is subjected to frequency analysis to obtain a frequency distribution and stored in the frequency distribution data storage unit 51b. For example, FFT can be used for the frequency analysis calculation.

  This frequency distribution is for determining the positions of the boundaries Ls and Bs by the boundary detection processing unit 50c, and the determination accuracy increases as the frequency to be obtained, that is, the cycle is shorter. A specific cycle can be appropriately determined based on a balance with the processing capability.

  For example, when the data measurement probe 1 descends and is immersed in the slag layer B and the molten metal layer L from the atmospheric layer A as in the present example, the boundary detection processing unit 50c performs the frequency distribution for each period obtained. When the FFT spectrum intensity value of the commercial power frequency in the molten metal container C installation area in the frequency distribution stored in the frequency distribution data storage unit 51b is equal to or lower than a predetermined threshold, It is determined that the position is the position of the boundary Bs immersed in the slag layer B from the atmosphere layer A, and the amount of lift of the sublance in the cycle is stored in the lift data storage unit 51c as the boundary Bs, that is, the slag layer level position.

  Further, when the data measurement probe 1 is further lowered and the value of the FFT spectrum intensity of the commercial power supply frequency becomes a predetermined threshold value or more, it is determined that the position is the position of the boundary Ls where the molten metal layer L is immersed from the slag layer B. Thus, the amount of lift of the sublance in the period is stored in the lift data storage 51c as the boundary Ls, that is, the molten metal layer level position. Here, the reason why the boundary detection processing unit 50c can determine the boundaries Bs and Ls based on the intensity change of the commercial power supply frequency in the frequency distribution as described above is as follows.

When the position of the metal electrode 20 of the data measurement probe 1 is in the atmospheric layer A, the slag layer B, and the molten metal layer L, the circuit characteristics between the electrodes and G (earth) are as shown in FIG. (A) is an equivalent circuit in the atmospheric layer, (b) is an equivalent circuit in the slag layer, and (c) is an equivalent circuit in the molten metal layer. The resistance R _{1 of the} atmospheric layer is theoretically close to infinity, but in reality, due to the high temperature, the atmosphere is ionized, iron powder, etc. is dancing at a high density, the insulation deterioration of the sublance cable, etc. Hundreds of kΩ. Still, the resistance value is relatively large. The resistances R ₂ and R ₃ in the slag layer and the molten metal are close to zero. In addition, although there is always noise of commercial power supply frequency of 50 Hz or 60 Hz in the earth or the atmosphere, the present inventors have found that the slag is melted particularly in the slag layer by moving the metal electrode 20 to each layer and changing the circuit characteristics. Since it is close to salt, the circuit characteristics have CR characteristics and the characteristic frequency is attenuated, and each boundary position can be detected by capturing changes using this characteristic.

  5A and 5B show the case where the metal electrode 20 of the data measurement probe 1 is immersed in the slag layer B from the atmospheric layer A when the molten metal container C is installed in an area where the commercial power supply frequency is 60 Hz. This shows an example of a change in the frequency distribution (FFT spectrum pattern), and shows that the spectral intensity of 60 Hz approaches zero in the slag layer B. FIGS. 6A to 6D further show examples of changes in frequency distribution (FFT spectrum pattern) when the metal electrode 20 of the data measurement probe 1 moves from the slag layer B to the molten metal layer (molten steel layer) L. It shows how the spectral intensity at 60 Hz increases. FIG. 7 is a graph of the example described in FIGS. 5 and 6 and shows changes in the spectral intensity (frequency peak) at 60 Hz.

  As shown in FIG. 8, the motion control processing unit 50 d controls the sub lance lifting / lowering device 4 so as to lower the data measurement probe 1 to a temporary optimum immersion depth estimated in advance. (A) in a figure is a graph which shows a mode that it falls to temporary provisional immersion depth. Then, when a detection signal of the molten metal layer surface Ls is output by the detection means (boundary detection processing unit 50c) during the immersion process of the probe 1, based on the detection signal, as shown in FIG. The immersion depth of the probe 1 in the molten metal layer L, that is, the optimum immersion depth is reset, and the subsequent lowering operation is controlled accordingly. That is, in this example, when the data measurement probe 1 reaches the surface Ls of the molten metal layer L in the same charge immersion process, it is detected that the surface has reached the surface, and the optimum immersion depth into the molten metal layer L from there is detected. Then, the amount of further lowering of the probe 1 is grasped in real time, and the lowering amount is reset.

  Therefore, various measurements and sample collection can be performed accurately and reliably at the optimum immersion depth reflecting the molten metal state in the charge, and the data measurement probe 1 stops at the optimum depth position. After measuring oxygen partial pressure, temperature, and the like by various sensors (reference numerals 11 to 13) and collecting a sample from the sample collection port 14, the molten metal layer L is pulled up to the atmosphere layer A through the slag layer B.

  Further, according to the present example, since the oxygen partial pressure, temperature, and the like are measured in the same charge, the level positions of the boundaries Bs and Ls, the thickness of the slag layer B, and the like are calculated. Based on the above, it is possible to more accurately control the oxygen flow rate in the final phase of decarburization by the main lance 6. Further, although not shown in FIG. 1, for example, an operation control processing unit for controlling the operation of the lifting device of the main lance 6 is provided in the computer 5, and the height of the main lance 6 is also accurately adjusted together with the control of the oxygen flow rate. The position can be variably controlled (see FIG. 9).

  Conventionally, when the oxygen potential in the slag is obtained from the oxygen partial pressure or temperature measured by the data measurement probe 1, it passes through the slag layer through a section where the oxygen potential is substantially constant (flat) when the probe 1 is raised. The oxygen potential of the relevant section was calculated as the oxygen potential of the slag layer by considering it as a section, but according to this, a reading error may occur when there are a plurality of flat sections. According to this example, as described above, since the oxygen partial pressure, temperature, and the like are measured, the level positions of the boundaries Bs and Ls and the thickness value of the slag layer B based thereon are accurately calculated, as shown in FIG. By using the value to multiply the oxygen potential by a window, the above-mentioned mistake can be prevented and the oxygen potential in the slag can be accurately obtained.

  In this example, the metal electrode 20 is provided on the outer peripheral surface of the protective cap 10 in an externally exposed state so that the positions of the boundaries Bs and Ls can be detected when the probe is lowered. However, the present invention is not limited to this, and the probe is raised. In this case, for example, the metal electrode 20 may be disposed inside the protective cap 10. Even if the metal electrode 20 is housed in the protective cap 10, the protective cap 10 is melted by the molten metal layer and the metal electrode 20 is exposed, and the boundaries Bs and Ls can be detected when the metal electrode 20 is raised. Even if the immersion depth cannot be reset using these position information, the oxygen flow rate by the main lance and the height position of the main lance can be accurately controlled, and the oxygen potential in the slag can be accurately controlled. The calculation can be performed similarly. In particular, when the metal electrode 20 is provided in the protective cap 10 as described above, the metal electrode 20 can also serve as the metal electrode 20 by the electrode of the oxygen sensor 11, the correction electrode 12, and other data measurement electrodes. It is.

  11 and 12 are explanatory diagrams showing a modification of the present invention. In the above-described example, the position of each boundary Ls, Bs is detected from the intensity change based on the fact that the intensity of the frequency of each frequency distribution changes in each layer due to the presence of 50 Hz or 60 Hz of the commercial power supply frequency. However, depending on the installation location and slag properties, the attenuation characteristics due to noise of the commercial power supply frequency may be reduced. In this example, in order to detect the boundary position more reliably and clearly even when such attenuation characteristics are reduced, a specific frequency is applied so that the attenuation characteristics are intentionally sharp with respect to the electrode voltage signal. It is.

  FIG. 11 is an explanatory diagram showing the configuration of this example. In the figure, reference numeral 9 denotes an oscillator for applying the specific frequency. Such a specific frequency may be the same frequency as the local commercial power supply frequency or may be a different frequency. If the frequency is the same, the signal from the oscillator 9 is added to the noise of the commercial power supply frequency, so that a clearer attenuation characteristic can be obtained and the boundary position can be reliably detected. In addition, in the case of different frequencies, basically, the boundary position can be reliably detected from the clear attenuation characteristic by the specific frequency applied by the oscillator 9, but the boundary position can also be detected from the attenuation characteristic of the commercial power supply frequency. Then, there is an effect that double confirmation is possible.

  In this example, a specific frequency (F (Hz)) different from the local commercial power supply frequency is applied by the oscillator 9, and the position of each boundary is detected by a change in the intensity of the specific frequency in each frequency distribution by the detection means. It was. FIG. 12 shows an example of the frequency distribution in the atmosphere, slag, and molten steel. Thus, determination is made based on the intensity change of a specific frequency having attenuation characteristics clearer than the commercial power supply frequency (50 Hz or 60 Hz). Thus, each boundary position can be detected more reliably.

  In the above embodiment, the boundary position between the atmospheric layer and the slag layer and the boundary position between the slag layer and the molten metal layer are detected in the presence of the slag layer. Can also be applied to the case of hot metal before blowing without the slag layer, that is, to detect the boundary position between the atmospheric layer and the molten metal layer. In this case, the spectral intensity of the frequency distribution is not attenuated to almost zero as in the above representative embodiment, but the intensity is different between the atmosphere and the molten metal (the resistance of the atmospheric layer is the resistance of the molten metal layer). Therefore, it is possible to detect the change and detect the boundary position. As for the boundary between the atmospheric layer and the molten metal layer, if the change in the electrode voltage is sharp, the boundary can be detected by the conventional method. Since the resistance becomes small and unstable due to the presence of the electrode, the electrode voltage itself does not change sharply. For this reason, the detection from the change in the spectral intensity can be detected more stably.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Data measurement probe 1a Tip part 3 Sublance 4 Elevator 5 Computer 6 Main lance 7 Operational amplifier 9 Oscillator 10 Protection cap 11 Oxygen sensor 12 Correction electrode 13 Temperature sensor 14 Sample sampling port 20 Metal electrode 50 Processing apparatus 50a Voltage data storage process part 50b Arithmetic processing unit 50c Boundary detection processing unit 50d Motion control processing unit 50e Elevation data storage processing unit 51 Storage means 51a Voltage data storage unit 51b Frequency distribution data storage unit 51c Elevation amount data storage unit A Atmospheric layer B Slag layer Bs Boundary C Molten metal Container G Ground L Molten metal layer Ls Boundary S Boundary position detection system

Claims (7)

A boundary position detection method for detecting a boundary between a molten metal layer in a molten metal container and a slag layer floating on the molten metal layer, and a boundary position between the slag layer and an air layer above the boundary,
Moving the metal electrode across the molten metal layer, the slag layer and the atmospheric layer;
During the movement, the frequency distribution of the electrode voltage signal is obtained by frequency analysis calculation at a predetermined cycle,
A boundary position detection method, wherein the position of each boundary is detected by a change in intensity of a commercial power frequency in an area where the molten metal container is installed in the frequency distribution. A boundary position detection method for detecting a boundary between a molten metal layer in a molten metal container and a slag layer floating on the molten metal layer, and a boundary position between the slag layer and an air layer above the boundary,
Moving the metal electrode across the molten metal layer, the slag layer and the atmospheric layer;
Apply a signal having a specific frequency that is the same as or different from the commercial power frequency in the area where the molten metal container is installed,
During the movement, the frequency distribution of the electrode voltage signal is obtained by frequency analysis calculation at a predetermined cycle,
A boundary position detection method, wherein the position of each boundary is detected by a change in intensity of the specific frequency in the frequency distribution.   The metal electrode is provided at the tip of a data measurement probe for measuring various data such as temperature / oxygen concentration of one or both of the molten metal and the slag layer, and the probe is lowered in the molten metal container to form the molten metal. The position of the probe can be controlled based on the information on the detected position before detecting the position of each boundary in the process of immersion and measuring various data in the molten metal or slag layer. The boundary position detection method described. A boundary position detection system for detecting a boundary between a molten metal layer in a molten metal container and a slag layer floating on the molten metal layer, and a boundary position between the slag layer and an atmospheric layer above the boundary,
A metal electrode movably provided across the molten metal layer, the slag layer and the atmospheric layer;
A computing means for calculating a frequency distribution by frequency analysis of the electrode voltage signal at a predetermined period;
Similarly, the computer detects the position of each boundary by a change in the intensity of the commercial power frequency in the area where the molten metal container is installed in each frequency distribution,
A boundary position detection system comprising: A boundary position detection system for detecting a boundary between a molten metal layer in a molten metal container and a slag layer floating on the molten metal layer, and a boundary position between the slag layer and an atmospheric layer above the boundary,
A metal electrode movably provided across the molten metal layer, the slag layer and the atmospheric layer;
A signal applying means for applying a signal having a specific frequency that is the same as or different from the commercial power supply frequency in the area where the molten metal container is installed;
A computing means for calculating a frequency distribution by frequency analysis of the electrode voltage signal at a predetermined period;
Similarly, the computer detects the position of each boundary by the change in the intensity of the specific frequency in each frequency distribution,
A boundary position detection system comprising:   The metal electrode is provided at the tip of a data measurement probe for measuring various data such as temperature / oxygen concentration of one or both of the molten metal and the slag layer, and the probe is lowered in the molten metal container to melt the molten metal. 5. The position of the probe can be controlled on the basis of the detected position information before the position of each boundary is detected in the process of immersing in the liquid and before measuring various data in the molten metal or slag layer. 5. The boundary position detection system according to 5.   6. A probe used in the boundary position detection system according to claim 4 or 5 for measuring various data such as temperature / oxygen concentration of one or both of the molten metal and the slag layer, wherein the metal electrode is provided at a tip portion. A data measurement probe.

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