Immersion device for temperature measurement and method for position detection

Abstract

To provide an immersion apparatus and a method for detecting a position of an optical core line using the immersion apparatus.SOLUTION: Provided is an immersion apparatus (10) for measuring a temperature of a metal melt (64) in a container (62) of an electric arc furnace (60) using an optical core line (50), which comprises: a blowing lance (28) for blowing a purge gas into an entry point to the container (62); and detection means for detecting a position of the optical core line (50). The optical core line (50) can be moved with respect to the entry point in a feed channel (20) and / or the blowing lance (28). The detection means is composed so as to detect the presence of the optical core line (50) in the blowing lance (28) or in the vicinity thereof. This enables a short distance between a tip of a fiber and a melt, and therefore enables a short time interval between temperature measurement sequences.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an immersion device for measuring the temperature of a metal melt in an electric arc furnace (EAF) vessel using an optical core wire, and a method for detecting the position of the optical core wire using the immersion device.

[0002] Metallurgical processes may be carried out in an electric arc furnace, particularly an EAF, as disclosed in U.S. Pat. No. 2,886,617 (A). To improve process control, the temperature of the metal melt needs to be measured. This can be done, for example, by using an optical fiber immersed in the melt and a corresponding detector connected to the fiber, as described in EP 2,799,824 (A1), EP 3,051,264 (A1), and EP 2,799,824 (A1). The optical fiber itself is coated with a metal. In the above process, the optical fiber is introduced into a disposable guide tube before measurement. At least a portion of the guide tube melts during use. To determine the quality of the temperature measurement, the position of the optical fiber with the guide tube within the supply means can be monitored. JP 09,304,185 (A) discloses a metal-sheathed optical fiber for measuring the temperature of molten steel, and the feed length of the optical fiber is measured by a motor with an encoder. A similar device is known from JP 07,151,608 (A).

[0003] In another process, the optical fiber can be provided as a substantially endless tube that is wound on a coil and unwound to make measurements. Such a feeding device for an optical fiber is described in EP 3051262 A1. EP 2940441 A1 describes an apparatus for temperature measurement that has a gap between the optical fiber and a guide tube. An alternative approach is described in JP 09243459 A, in which the fiber is cut to define a known tip position.

[0004] The object of the present invention is to improve the temperature measurement in an electric arc furnace vessel.

[0005] The problem according to the invention is solved by an immersion device according to claim 1 and a method for detecting the position of an optical core according to the additional claims. Advantageous embodiments are defined in the dependent claims.

[0006] The object is achieved by an immersion device for measuring the temperature of a metal melt in an electric arc furnace vessel using an optical core. The immersion device comprises an injection lance for injecting purge gas into an entry point into the vessel and detection means for detecting the position of the optical core. The immersion device is configured so that the optical core can move within the feed channel and / or the injection lance relative to the entry point. The detection means is configured to detect the presence of the optical core in or near the injection lance.

[0007] Because the tip of the optical core melts during temperature measurement, the position of the optical core needs to be determined before each temperature measurement. In conventional solutions, the position of the optical core is detected in the supply tube and therefore at a position relatively far away from the container. Therefore, the optical core needs to move back and forth a long distance between the temperature measurement and the position measurement, which is time-consuming. Therefore, using conventional techniques, the interval between two temperature measurements is long.

[0008] Detecting the presence of the optical core in or near the blowing lance results in faster transport of the optical core, thus allowing for shorter time intervals between measurements. This is particularly important because the temperature of the molten steel bath during EAF operation can change at a rate of up to 70°C per minute. More measurements can be taken, thus enabling better process control. The distance from the tip to the melt can be kept significantly lower. In addition, debris or abrasion caused by the returning hot optical core can constantly contaminate and damage or block the tube. By reducing the optical core's travel path within the supply channel, this risk can be minimized. According to the present invention, the movement of the optical core's tip can be limited to the easily replaceable blowing lance, allowing for a simple solution in the event of contamination or damage. The part of the detection means close to the hot optical core can be easily replaced. In addition, the tip can be immersed at the best landing point, making temperature measurements more reliable.

[0009] The blowing lance is a lance through which purge gas can be blown into the vessel. This can help prevent metal, slag, and / or debris from entering the feed channel. The blowing lance can be replaceable. Typically, the blowing lance is straight, i.e., not curved, to feed the optical core along a straight path toward the melt. The blowing lance can also be manufactured in one piece. The blowing lance is particularly arranged coaxially with the feed channel and / or axially adjacent to the feed channel. In particular, the feed channel is adjacent to the blowing lance in a direction away from the vessel. A portion of the detection means for detecting the presence of the optical core can be arranged on the blowing lance. A portion of the detection means can be arranged close to the blowing lance, for example on the feed channel, near the connection between the blowing lance and the feed channel, and / or between the blowing lance and the feed channel.

[0010] The blowing lance can serve to guide the optical core into and / or out of the melt in the vessel. The purge gas cools the blowing lance and / or the optical core within the blowing lance. During the measurement sequence, the optical core can move within the feed channel and the blowing lance towards the melt.

[0011] The feed channel serves to feed the optical core into and / or out of the container. The feed channel defines a linear and / or curved path along which the optical core can move. In particular, the moving means is configured to move the optical core along the path defined by the feed channel. The feed channel is in particular closed and / or has a circular cross section. The feed channel may comprise a feed tube, for example a metal tube, i.e. a tube through which the optical core fiber can be fed. The feed channel may be formed by a metal wall. The feed channel may have an inner diameter greater than 7 mm, in particular greater than 9 mm and / or less than 15 mm, in particular less than 12 mm. The device may comprise the feed channel. The feed channel and the blowing lance together may be referred to as a feed system. The feed system may further comprise a detection means or detector.

[0012] The optical core includes an optical fiber, which may be, for example, a glass fiber. The optical fiber may be a graded-index fiber with a diameter of 50 μm or 62.5 μm. In particular, the optical core includes a metal tube disposed around the fiber, i.e., the optical core is a metal-coated optical fiber, also known as FiMT (Fiber in a Metal Tube). The metal tube may have an outer diameter of more than 1 mm, in particular 1.3 mm and / or less than 3 mm, in particular 2.5 mm. The wall thickness of the metal tube may be more than 0.1 mm and / or less than 0.3 mm, in particular less than 0.2 mm. The optical core may further include an outer tube disposed around the metal tube. The outer tube may be made of metal. The outer tube may have an outer diameter of more than 4 mm and / or less than 8 mm, in particular about 6 mm. The wall thickness of the outer tube may be more than 0.2 mm, in particular more than 0.3 mm and / or less than 0.7 mm, in particular less than 0.5 mm.

[0013] The tip of the optical core is the end that is immersed in the melt to measure the temperature. The position of the tip of the optical core typically corresponds to the position of the tip of the optical fiber. In particular, the optical core is consumed in a direction from the tip to the other end on the opposite side. After each measurement sequence, another part of the optical core becomes the tip. The other end may be connected to a detection unit to evaluate signals measured and / or transmitted by the optical core to determine the temperature. The other end is not consumed during the measurement. The detection unit may be configured to receive optical signals transmitted by the optical fiber, particularly in the IR wavelength range. The detection unit may be a pyrometer.

[0014] Detecting the presence of an optical core means detecting information regarding whether an optical core is present at a certain position. This facilitates detecting the position of the optical core. In particular, the presence of an optical core can be detected at a defined position of the blowing lance and / or the supply channel. This can be realized by positioning a part of the detection means at a known fixed position relative to the supply channel and / or the blowing lance. In particular, the detection means is configured to detect the presence of an optical core at a distance of less than 4 m, in particular less than 2 m, and in one embodiment less than 1 m, from the outer wall of the EAF vessel. In particular, the detection position is on the outer wall. Preferably, the detection means is configured to detect the presence of an optical core at a distance of less than 1 m, in particular less than 50 cm, and in one embodiment less than 20 cm, from the blowing lance. The detection position can be on the blowing lance. The distance to the blowing lance is in particular an axial distance.

[0015] The immersion device is particularly stationary. In particular, the immersion device is configured so that it can be located on the outer wall of the container, or, if present, on a platform on the side of the container. If located on the outer wall, the immersion device may be installed on an eccentric bottom tap (EBT) platform or on the side wall of the container. Thus, the optical core can move downward into the container from a stationary point. The platform may be part of the side wall and / or may be aligned essentially horizontally. In particular, the entry point of the container is located on the platform and / or the entry point of the container is an opening aligned essentially vertically.

[0016] In one configuration, the detection means includes an inductive sensor for detecting the presence of the optical core. The inductive sensor may be located on or adjacent to the blowing lance. For example, the inductive sensor may be located on the supply channel and / or supply tube. Two inductive sensors may be used to determine the position of the tip between the two inductive sensors.

[0017] In one embodiment, the detection means comprises a detector for measuring a characteristic of the gas flow. In particular, the detector is configured to measure the flow rate of the gas flow, the flow velocity of the gas flow, and / or the gas pressure in the gas flow. Thus, the gas flow can be used to detect the presence of the optical core. In particular, the gas flow is realized in or close to the blowing lance, whereby the presence of the optical core affects the gas flow, for example by blocking at least a part of the flow path of the gas flow. By measuring the characteristic, the presence of the optical core can be detected. The device may comprise a suitable gas source. The detector may be located close to or remote from the blowing lance and connected to a gas line. Typically, the gas line has a high temperature resistance.

[0018] The term gas in the context of the present invention refers to any gaseous substance, such as a gas, a gas mixture, and / or a dispersion having a gas as the continuous medium. Thus, the gas stream can be a flow of a mixture of gases, such as air.

[0019] This embodiment allows for durable, high-temperature resistant position detection. During intended use, locations in or near the blowing lance are exposed to adverse conditions, including high temperatures of several hundred degrees Celsius due to the proximity of the EAF vessel, flames, and sparks. This embodiment eliminates electrical or electronic components in the heated zone and is therefore particularly robust. Technical effort is low, as no shielding or thermal protection is required. It is further noted that the tip of the optical core, whose position is detected, was in the liquid metal one second prior to detection. The gas flow characteristics are robust and have been shown to accurately detect the presence of the optical core at high temperatures. Additionally, particularly fast detection of the tip is possible.

[0020] In one embodiment, the immersion device comprises a moving means for moving the optical core within the supply channel and / or the blowing lance relative to the entry point. The moving means moves the optical core relative to the supply channel and / or the blowing lance along the longitudinal extension of the supply channel or the blowing lance. The moving means is particularly configured to move the optical core so that the tip moves into and out of the container and / or into and out of the melt contained in the container. Thus, the moving means may be configured for forward and / or backward movement of the optical core. The movement of the optical core is particularly along a linear or curved path. The moving means may include a motor.

[0021] In a further embodiment, the moving means is configured to feed the optical core from the coil and / or to rewind unused optical core onto the coil.

[0022] Measurement close to the vessel has been shown to work particularly well using a coiled optical core. The type of optical core used can also be reliably monitored by gas flow detection. This embodiment allows for a reliable, low-effort method of providing large (virtually infinite) lengths of optical core for multiple measurements. Thus, frequent temperature measurements can be made over at least one full EAF operating cycle, thus allowing for maximum process control.

[0023] In a further embodiment, the supply channel and / or the blowing lance has a first opening and / or a second opening. The gas supply means may be connected to the first opening for introducing pressurized gas into the first opening. The detector may be connected to the second opening by a detector line.

[0024] In particular, the first opening and / or the second opening are radial openings relative to the longitudinal extension of the supply channel and / or the blowing lance. In particular, the two openings are at the same axial position relative to the longitudinal extension of the supply channel or the blowing lance. The gas flow realized through the openings is influenced by the optical core, and the detection means can detect the characteristics of the gas flow to detect the influence and thus the presence or absence of the optical core. The openings can be used to detect whether the optical core is present between the openings. Therefore, information can be derived as to whether the tip of the optical core is on the container side or on the opposite side of the opening.

[0025] The term "connect" or "connection" relates to a flow connection for allowing the respective gas flow. The detector line is the fluid connection between the detector and the second opening. Generally, a line in the sense of the present invention means a fluid connection independent of its type, which may be, for example, a pipe, a tube, etc.

[0026] This embodiment has shown reliable results even when the radial position of the optical core in the supply channel or blowing lance is unknown due to the radial gap between the outer diameter of the optical core and the corresponding inner wall. A jump in properties such as flow or pressure can be observed when the tip passes a position between the openings. Furthermore, this embodiment allows particularly reliable and uninterrupted operation.

[0027] In a further embodiment, the first and second openings are coaxially aligned and / or positioned on opposite sides of the cross section of the feed channel or injection lance. In other words, the openings share a common axis, which may extend perpendicular to the feed channel axis. Thus, a direct gas flow can be established between the openings, allowing for specific and accurate position detection. The openings may be positioned on opposite sides of the feed channel with the channel diameter between them, thus utilizing the complete cross section.

[0028] In a further embodiment, the feed channel has a straight portion located adjacent to the blowing lance and a bent portion located adjacent to the straight portion. The first opening and the second opening may be located adjacent to where the straight portion and the bent portion meet. Alternatively, the blowing lance is straight so that the optical core can be fed toward the container along a straight path, and the feed channel has a bent portion located adjacent to the blowing lance. In this case, the first opening and the second opening may be located adjacent to where the blowing lance and the feed channel meet.

[0029] The straight portion is directed toward the container and / or between the bent portion and the container. Thus, the optical core can be introduced into the melt and returned from the melt along a straight path without bending. The mechanical properties of the optical core change due to the heat to which the optical core is exposed during temperature measurement and / or subsequent cooling. In particular, the flexibility of the optical core decreases. Moving the optical core without bending avoids permanent deformation, and thus avoids wear, stress, and friction of the optical core, ingress of material from the container, and blockage of the supply system. Further movement of the optical core is prevented.

[0030] The bent portion is located on the side of the straight portion facing away from the container, so the space requirements of the device can be minimized.

[0031] The two openings are located close to the contact point. In particular, the axial distance from either of the two openings to the contact point relative to the longitudinal direction of the feed channel and / or the injection lance is less than 25 cm, preferably less than 15 cm. In one configuration, the axial distance is less than 5 cm or zero.

[0032] In one embodiment, the immersion apparatus includes a purge gas line for connecting a high-pressure gas source to the injection lance to generate a first purge gas flow in the injection lance toward the vessel and / or the melt contained therein. The high-pressure gas source provides a gas or gas mixture at a pressure of at least 5 bar, particularly at least 10 bar. The purge gas line is therefore configured to withstand the pressures mentioned above. The purge gas line is preferably designed as a tube and / or made of metal. The purge gas flow helps to keep the hollow space in the injection lance free of debris from the vessel, ensuring reliable operation of the core wire. This helps to keep the supply channel free of slag and frozen metal from the vessel, thus ensuring unhindered operation.

[0033] In a further embodiment, the purge gas line is connected to a flow divider that splits the gas flow from the high-pressure gas source into two lines. The first line is connected to the blowing lance to generate the first purge gas flow, and the second line is connected to the first opening. In other words, a single high-pressure gas source is used for both the purge gas flow and position detection. Therefore, an existing gas source can be used to detect the position of the optical core, which can minimize technical effort. The first line and / or the second line may be made of metal and / or designed as a tube. The first line and / or the second line may be very short and / or designed as a gas passage or opening for gas to pass through.

[0034] In a further embodiment, the submerged apparatus includes a detector line purge line connecting the purge gas line to the detector line to generate a second purge gas flow in the detector line through the second opening into the blowing lance or supply channel. In particular, a periodic and / or temporary gas flow is generated to purge the detector line. Thus, the detector line can be kept free of debris. In other words, the gas flow in the detector line can be reversed. A switching valve may be disposed in the detector line purge line to selectively generate the second purge gas flow. The switching valve may be controlled by the submerged apparatus control device. This embodiment allows for particularly durable operation due to the inclusion of detector line purging.

[0035] In one embodiment, the end of the blowing lance, which is or can be directed toward the vessel and / or the melt contained therein, is realized as a Laval nozzle. This allows the first purge gas flow to be introduced into the vessel at high and / or supersonic speed. Thus, slag floating on the melt below the optical core can be removed before and / or during the introduction of the optical core. This prevents blockages in the supply system and improves temperature measurement. Additionally, the optical core is cooled in the vessel, which increases its durability and enables particularly accurate temperature measurement.

[0036] In a further embodiment, the immersion device comprises an encoder configured to monitor the movement of the optical core from a known starting point. In particular, the movement means includes a servo motor that functions as an encoder. The encoder may be configured to monitor the distance the optical core moves from the known starting point. The starting point is in particular defined by the position of the tip detected by the detection means. Thus, after position measurement, the encoder ensures that the position of the tip is known during the subsequent movement of the optical core. Thus, a defined immersion depth of the optical core into the melt can be ensured. Temperature measurement is further improved.

[0037] In one configuration, the encoder may be part of the moving means and / or a motor configured by the moving means. The motor may be a servo motor and / or include a servo drive for monitoring the motor position. Additionally or alternatively, the encoder may be located independently of the moving means. In the case of a servo motor and an additional encoder, any displacement of the optical core due to, for example, an occlusion that is not detected by the servo motor alone can still be measured. This allows for particularly accurate and obstruction-free position measurements.

[0038] In one embodiment, the dipping device comprises a control device for controlling the movement of the tip of the optical core into and / or out of the melt by the movement means. The control device may further be configured to control the detection of the presence of the optical core by the detection means. In particular, the control device is an electronic control device such as a microcontroller or a computer.

[0039] In a further embodiment, the immersion device is configured such that the detection means can monitor the presence of the optical core at a specific position during its movement. After it is detected that the leading edge of the optical core has passed that position, the movement of the optical core can be stopped. This can be achieved in particular by a control device. Thus, the movement of the optical core is limited to the required amount. This increases the measurement speed and enables a high degree of process control.

[0040] A further aspect of the invention is an immersion apparatus for measuring temperature using an optical core in an EAF vessel. The immersion apparatus comprises a blowing lance connection device for mechanically connecting a blowing lance. The optical core is movable within the feed channel, within the blowing lance, and / or within the blowing lance connection device relative to the entry point. The apparatus further comprises detection means for detecting the position of the optical core. The detection means is configured to detect the presence of the optical core in or near the blowing lance connection device.

[0041] A further aspect of the invention is a method for detecting the position of an optical core using a dipping device according to the invention. The method comprises moving an optical core in the supply channel and / or the blowing lance by means of a moving means. The method further comprises detecting by means of a detecting means whether the optical core is present at a position in or near the blowing lance. All features, advantages and embodiments mentioned with respect to the device according to the invention also apply to the above aspects and methods of the invention, and vice versa.

[0042] In particular, the detection means includes a portion located at a location in or near the blowing lance to detect the presence of the optical core at that location. In particular, the method includes measuring a temperature in the vessel using the optical core. Moving may include advancing the optical core before measuring and / or retracting the optical core after measuring. Multiple measurements may be taken consecutively.

[0043] In one embodiment, the submersion device comprises a first opening and a second opening in the supply channel or in the blowing lance. The detection means may include a detector connected to the second opening. The detecting step may include introducing pressurized gas into the first opening and / or detecting a characteristic of the gas flow by the detector. In particular, the characteristic is evaluated by an evaluation unit of the device, which may be part of the control device.

[0044] After the detecting step, the method may include advancing the optical core by a moving means along a predetermined distance toward the melt to immerse the tip in the melt to a predetermined depth. This movement may be monitored by an encoder and / or controlled by a control device. The position may be detected at the start and / or end of a temperature measurement sequence. In particular, the position is detected before the first measurement sequence. Reliable position detection is possible with only one detection means.

[0045] In a further embodiment, the moving step includes retracting the optical core away from the container and / or melt at a first speed, stopping the retraction movement, and advancing the optical core toward the container and / or melt at a second speed, which may be lower than the first speed. The presence of the optical core may be detected during the retraction movement and / or the advancing movement. The optical core moves, in particular, within the feed channel and / or the blowing lance.

[0046] In two-step detection, the first detection may provide an approximate position of the tip. The first detection may be used to trigger the stopping of the fast retraction movement. The fast retraction is advantageous due to adverse conditions in proximity to the melt and to ensure a rapid measurement. The second detection may be performed during the slower movement, thus allowing a very accurate position determination.

[0047] In the following, exemplary embodiments of the present invention will be described in detail with reference to the figures. The features of the exemplary embodiments may be combined individually or in multiple combinations with the claimed subject matter, unless otherwise indicated. The scope of protection claimed is not limited to the exemplary embodiments. [Brief explanation of the drawings]

[0048] The diagram shows: [Figure 1] FIG. 2 is a cross-sectional side view of the immersion device. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 1 is a cross-sectional side view of a detail of the immersion device. [Figure 5] FIG. 2 is a schematic cross-sectional view of another detail of the immersion device. [Figure 6] 1 is a diagram of an electric arc furnace with an immersion device.

[0049] 1 shows a cross-sectional view of an immersion apparatus 10 according to the present invention for measuring the temperature of a metal melt in an EAF vessel by means of an optical core 50. The optical core 50 is vertically aligned for being fed downwards through the feed channel 20 and the blowing lance 28 into the melt using a moving means, not shown here, arranged at a distance upwards. Preferably, the moving means feeds the optical core 50 from an upwardly arranged coil and rewinds unused fiber onto the coil.

[0050] The immersion apparatus 10 includes a blowing lance 28 for blowing purge gas downward into the inlet point of the vessel. This is shown in detail in FIG. 6 . The blowing lance 28 is a metal tube having an interior space 32 in which the optical core 50 can move surrounded by the purge gas. The front end of the blowing lance 28, directed toward the melt, is realized as a Laval nozzle 44. With respect to the longitudinal extension of the optical core 50, the blowing lance 28 is located axially forward adjacent to the supply channel 20. In the illustrated embodiment, the supply channel 20 includes a metallic supply tube 29 and a vertically aligned guide channel formed by the central body 72 of the immersion apparatus 10. The guide channel is axially adjacent to and coaxial with the blowing lance 28 and the supply tube 29. The guide channel is located between the blowing lance 28 and the supply tube 29, as also shown in FIG. 4 . In other embodiments, the blowing lance 28 may be located axially adjacent to the supply tube 29 .

[0051] The blowing lance 28 is removably attached to the central body 72. The supply tube 29 is shown in part cut away in Figures 1 and 3, thus revealing the optical core 50. In particular, however, the supply tube 29 continues further to the transfer means.

[0052] The immersion device 10 includes a detection means for detecting the position of the optical core 50. The detection means is configured to detect the presence of the tip 52 of the optical core 50 near the upper end of the blowing lance 28. The detection means includes a detector for measuring a characteristic of the gas flow. The detector is connected to a detector line, not shown here. The detection means further includes a first opening 21 and a second opening 22 arranged coaxially within the supply channel 20. In the illustrated embodiment, the openings 21 and 22 are located on opposite positions of the cross section of the guide channel formed by the central body 72 of the immersion device 10. The first opening 21 is connected to a gas supply means (not shown here) to achieve a flow of pressurized gas through the first opening 21 into the supply channel 20 and through the second opening 22 out of the supply channel 20. When the tip 52 of the optical core 50 moves forward or backward through the openings, the gas flow is affected, and the effect can be detected by the detector. In one configuration, the detection is a pressure measurement. A change in pressure related to the position of the tip 52 is detected. While the tip 52 is between the blowing side and the receiving side (first opening 21 and second opening 22, respectively), a lower pressure is observed. When the gas path is no longer blocked, a higher pressure is observed. The pressure measurement is particularly robust and durable.

[0053] The immersion apparatus 10 includes a purge gas line 32 for connecting a high-pressure gas source to establish a purge gas flow in the blowing lance 28 toward the melt contained in the EAF vessel. In the illustrated embodiment, the purge gas line 30 is connected to a flow divider 40, which is realized as a chamber having at least two outlet openings. At least one outlet opening is connected to a first line 41 extending circumferentially around the guide channel of the central body 72. The first line 41 is configured to direct the introduced gas into the space 32 of the blowing lance 28 to establish the purge gas flow. At least one further outlet opening is connected to a second radial line 42 connected to the first opening 21 to generate a gas flow for position detection.

[0054] FIG. 2 shows the apparatus 10, particularly the apparatus 10 of FIG. 1, in a front view. FIG. 3 shows the apparatus 10, particularly the apparatus of FIGS. 1 and / or 2, in a perspective view. The apparatus 10 is shown to include two clamping devices 70 that allow for quick and easy tool-less replacement of the blow lance 28. Each clamping device 70 includes a clamping means that, when the clamping device 70 is in a closed position, applies a compressive force on the flange of the blow lance 28 and the flange of the central body 72, axially forcing the flanges together. Each clamping device 70 includes a handle 71 that can be pivoted to open the clamping device 70 for replacement of the blow lance 28 and to close the clamping device 70 for tool-less installation of the blow lance 28.

[0055] FIG. 5 shows a schematic detail of another configuration of the immersion apparatus, in which the supply channel 20 is realized as a supply tube 29 and is located adjacent to the blowing lance 28. The blowing lance 28 is straight to supply the optical core 50 toward the melt on a linear path. The supply channel 29 has a bent portion 26 to save space. A location 25 is located between the straight portion 24 represented by the blowing lance 28 and the bent portion 26. The axial positions of the first opening 21 and the second opening 22, and therefore the axial positions of the inlet of the purge gas line 30 and the connection of the detector line 34, are at or near the location 25. The pressurized gas is split into a purge gas flow within the blowing lance 28 and a gas flow 38 to be measured. The gas forming the gas flow 38, whose pressure or flow is to be measured, enters through the first opening 21. The locations of the openings 21 and 22 may also be interchanged. The openings 21, 22 are coaxially aligned and located on opposite positions of the cross section of the feed channel 20 and the blowing lance 28.

[0056] FIG. 6 shows an electric arc furnace (EAF) 60 having an immersion apparatus 10. The EAF 60 comprises a vessel 62 containing a metal melt 64, a movable lid 68, and a platform 67 disposed on the side of the vessel 62. The entry point into the vessel 62, through which the optical core 50 enters the vessel 62, is disposed on the platform 67. The immersion apparatus 10 is also disposed on the platform 67. FIG. 6 merely shows the relative positions of the immersion apparatus and the EAF. However, the immersion apparatus is typically configured to be fixed on the platform 67, so that the feed tube 29, blow lance 28, and tip 52 remain stationary when the vessel 62 is tilted during operation.

[0057] The optical core 50 is disposed on a coil 76. The optical core 50 is moved, i.e., unwound from the coil 76 and rewound onto the coil 76, by a moving means 74. The moving means 74 includes rollers for moving the optical core 50, and may include a servo motor for driving at least one of the rollers. Between the moving means 74 and the blowing lance 28, the optical core 50 is guided into the supply channel 20. The supply channel 20 has a curved portion 26 and a straight portion 24 directed toward the container 62. The supply channel includes a supply tube 29 and a guide channel formed by the central body of the immersion device 10. For clarity, the detection means are not shown here. [Explanation of symbols]

[0058] 10 Immersion equipment 20 Supply Channels 21 First opening 22 Second Opening 24 Straight section 25 Locations 26 Bent part 28 Blowing Lance 29 Supply Tube 30 Purge gas line 32 spaces 34 detector lines 38 Gas Flow 40 flow diverter 41 First Line 42 Second Line 44 Laval Nozzle 50 Optical core line 52 Tip 60 Electric Arc Furnace 62 Container 64 Melt 67 Platform 68 Lid 70 Clamping device 71 Handle 72 Central body 74 Transportation 76 Coil

Claims

1. An immersion device (10) for measuring the temperature of a metal melt (64) in a vessel (62) of an electric arc furnace (60) using an optical fiber (50), comprising: The optical core (50) includes an optical fiber within a metal tube and an outer metal tube disposed around the metal tube; The immersion device (10) comprises a blowing lance (28) for blowing a purge gas into an entry point into the container (62) and a detection means for detecting the position of the tip of the optical core (50), the optical core (50) being movable in the supply channel (20) and / or in the blowing lance (28) relative to the entry point, the detection means is configured to detect the presence of the optical core (50) in or near the blowing lance (28); The immersion device (10) is characterized in that it is installed in a stationary state.

2. 2. The immersion device (10) of claim 1, characterized in that the detection means includes a detector for measuring a characteristic of the gas flow (38), the detector being configured to measure, in particular, the flow rate of the gas flow (38), the flow velocity of the gas flow (38), and / or the gas pressure within the gas flow (38).

3. Immersion device (10) according to claim 1 or 2, characterized in that the detection means comprises an inductive sensor for detecting the presence of the optical core (50).

4. The immersion device (10) according to claim 1, characterized in that it comprises a moving means (74) for moving the optical core (50) in the supply channel (20) and / or in the blowing lance (28) relative to the entry point.

5. 5. The immersion device (10) of claim 4, wherein the moving means (74) is configured to feed the optical core (50) from a coil (76) and to wind unused fiber onto the coil (76).

6. 6. The immersion device (10) according to claim 2, 4 or 5, characterized in that the supply channel (20) or the blowing lance (28) has a first opening (21) and a second opening (22), a gas supply means can be connected to the first opening (21) for introducing pressurized gas into the first opening (21), and the detection means is connected to the second opening (22) by a detector line (34).

7. the first opening (21) and the second opening (22) are coaxially aligned; 7. The immersion device (10) according to claim 6, characterized in that the first opening (21) and the second opening (22) are arranged on opposite positions of a cross section of the supply channel (20) or the blowing lance (28), respectively.

8. the supply channel (20) has a straight portion (24) located adjacent to the blowing lance (28) and a bent portion (26) located adjacent to the straight portion (24), and the first opening (21) and the second opening (22) are located adjacent to a location (25) where the straight portion (24) and the bent portion (26) meet; or 8. The immersion device (10) of claim 6 or 7, characterized in that the blowing lance (28) is straight to supply the optical core (50) along a straight path towards the melt (64), the supply channel (20) has a bent portion (26) located adjacent to the blowing lance (28), and the first opening (21) and the second opening (22) are located close to where the blowing lance (28) and the supply channel (20) contact each other.

9. 9. The immersion apparatus (10) according to any one of claims 1 to 8, characterized in that it comprises a purge gas line (30) for connecting a high-pressure gas source to the injection lance (28) to generate a first purge gas flow in the injection lance (28) towards the melt (64).

10. 10. The immersion device (10) according to claim 9, characterized in that the end of the injection lance (28) directed towards the melt (64) is realized as a Laval nozzle (44).

11. The immersion device (10) according to claim 4 or 5, characterized in that it comprises a control device for controlling the movement of the tip (52) of the optical core (50) into and / or out of the melt (64) by the moving means (74).

12. The immersion device (10) is characterized in that the detection means is capable of monitoring the presence of the optical core (50) at a specific position during the movement of the optical core (50), and the movement of the optical core (50) can be stopped after it is detected that the tip (52) of the optical core (50) has passed through the position.

13. A method for detecting the position of an optical core (50) using an immersion device (10) according to any one of claims 1 to 12, comprising: moving the optical core (50) in the supply channel (20) and / or the blowing lance (28) by a moving means (74); Detecting by the detecting means whether the optical core (50) is present in the blowing lance (28) or in the vicinity of the blowing lance (28); A method comprising:

14. The detecting step includes: introducing pressurized gas into the first opening (21); 14. A method as claimed in claim 13 when dependent on any one of claims 6 to 8, comprising detecting a characteristic of the gas flow (38) with said detector.

15. 15. The method of claim 13 or 14, wherein the moving step includes retracting the optical core (50) away from the melt (64) at a first speed, stopping the retracting movement, and advancing the optical core (50) towards the melt (64) at a second speed lower than the first speed, and the presence of the optical core (50) is detected during the retracting movement and the advancing movement.

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