MEASUREMENT APPARATUS AND METHOD FOR MEASURING THE TEMPERATURE OF A MOLTEN METAL BATH USING OPTICAL DEVICES - Patent application

Abstract

The present invention relates to a measuring device for measuring the temperature of a molten metal bath, comprising an optical device, a detection means, a storage unit for the optical device, a rotatable support for the storage unit for the optical device, a movement means, a straightening means, a housing and a guide system connected to the housing. The housing encloses the detection means, the storage unit for the optical device, the rotatable support for the storage unit for the optical device, the movement means and the straightening means. The movement means is adapted to pay out and retract the optical device and comprises at least one motor for driving the rotatable support for the storage unit for the optical device back and forth and payout means for paying out the optical device driven by the at least one motor for driving back and forth. The present invention also relates to a method of using a corresponding measuring device for measuring the temperature of a molten metal bath.

Description

[Technical Field]

[0001] The present invention relates to a measuring device for measuring the temperature of a molten metal bath, comprising an optical device, a detection means, a storage unit for the optical device, a rotatable support for the storage unit for the optical device, a movement means, a straightening means, a housing, and a guide system connected to the housing. The housing encloses the detection means, the storage unit for the optical device, the rotatable support for the storage unit for the optical device, the movement means, and the straightening means. The movement means is adapted to extend and retract the optical device and comprises at least one motor for driving the rotatable support for the storage unit for the optical device back and forth, and a payout means for paying out the optical device, driven by the at least one motor for driving back and forth. The present invention also relates to a method of using a corresponding measuring device for measuring the temperature of a molten metal bath. [Background technology]

[0002] The temperature of a molten metal bath in a metallurgical vessel is a critical parameter during the metal production process and determines the quality of the resulting product. Typically, molten metal temperature measurement is achieved using well-known immersion thermocouples, such as those described in U.S. Pat. No. 2,993,944(A). Such thermocouples can be manually immersed by an operator using a steel pole with electrical wiring and connections adapted to transmit the thermocouple signal to appropriate equipment. In addition, many automated thermocouple immersion machine systems are currently available for providing thermocouple immersion. Another possible means for measuring the temperature of a molten metal bath, particularly iron or steel, in the melting environment of an electric arc furnace (EAF) involves immersing an optical fiber into the molten metal. The optical fiber may be wound on a coil and provided as a substantially endless fiber that is unwound to perform measurements. To measure the temperature of the molten metal bath, such an optical fiber is unwound into the metallurgical vessel, from which it can transmit thermal radiation received from the molten metal to a detector, where the optical signal is converted into a temperature value. After the measurement, the optical fiber can be retracted.

[0003] The accuracy of the results obtained and the distortion-free operation of such measurements depend on several parameters.

[0004] One important parameter is the condition of the optical fiber at the time the measurement is performed. In the harsh environment of measurement situations in metallurgical facilities, optical fibers are exposed to a degrading environment. Therefore, such optical fibers are typically surrounded by a protective cover, such as a metal tube. Optical fibers surrounded by a metal tube are also often referred to as optical core wires or optical fibers coated with metal tubes (FIMT). Optical devices have been developed that include such optical fibers and additional protective measures, such as additional metal tubes or additional layers of protective material, as disclosed, for example, in U.S. Patent Application Publication No. 2007268477 (A1) and Japanese Patent Application Laid-Open No. 10176954 (A). Depending on the design of such optical devices, the protective measures can effectively shield the optical fiber from thermal effects but can still be sensitive to other external physical factors.

[0005] Another important part of the measurement process has been found to be the accurate payout of the optical device. Payout includes acceleration and deceleration and is defined by a terminal velocity. In particular, optical devices with relatively small cross sections and thin metal tubes are sensitive to the effects of friction and impact, which can lead to damage to the optical fiber within the optical device. Furthermore, these types of optical devices need to be paid out fast enough to reach an appropriate immersion depth in the molten metal bath before being decomposed and damaged by the measurement environment. This requires high payout speeds and high acceleration and deceleration rates. Therefore, these fragile optical devices pose additional challenges to the technical installation of the immersion device.

[0006] An exemplary immersion device for unwinding optical devices is described in EP 3051262 A1. Optical devices, particularly FIMTs, are unwound from a coil through an immersed guide tube by two motor-driven feeders, and the device is also suitable for unwinding the optical device. A constant tension is applied by a load. While the described invention solves the problem of possible recoil when the optical device is unwound, it applies high tension to the wire, which can cause damage. Furthermore, the system lacks autonomy because every measurement requires a new shielding tube, which is demanding in terms of space requirements.

[0007] A solution to the need for constant tension on an optical device is disclosed in JP 09101206(A). The immersion device comprises two unwinding means adapted for forward and backward unwinding, which are operated sequentially and independently of each other. The device further comprises a looper, on which the optical device is guided during immersion.

[0008] Typically, immersion devices are placed at some distance from the vessel containing the molten metal because the available space near the vessel is limited and the environment is harsh in terms of temperature and potential for damaging the device. Newer generations of optical devices are less robust to the effects they may be exposed to in such environments, and therefore a protected placement near the device's operating location is desirable.

[0009] For example, EP 1966573 A1 addresses the problem of heat load on the measurement system by placing the components in an insulated housing. The disclosed device requires space and must be located away from the container. Summary of the Invention [Problem to be solved by the invention]

[0010] In view of the prior art, there is a need for a measurement device and method for using the same that allows for accurate immersion of fragile optical devices to obtain highly accurate results.

[0011] It is an object of the present invention to provide a measurement device for measuring the temperature of a molten metal bath that solves at least one of the above-mentioned problems. In particular, one object of the present invention is to provide a measurement device that minimizes the degree of friction and twisting on the device and its internal optical fiber, allowing for immersion of fragile optical devices with high accuracy and control. A further object of the present invention is to provide a measurement device that ensures measurements by the optical device at a constant position on the surface of the molten metal bath over repeated immersion cycles. A further object of the present invention is to provide a measurement device that minimizes the extent to which the optical device is unprotected during immersion, thus providing a measurement device that operates reliably regardless of the conditions surrounding the measurement. A further aspect addressed by the present invention is to provide a measurement device that allows for low-maintenance operation.

[0012] It is a further object of the present invention to provide a method for utilizing a measurement device to measure the temperature of a molten metal bath.

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

[0014] The present invention provides a measuring device for measuring the temperature of a molten metal bath, comprising an optical device, a detecting means, a storage unit for the optical device, a rotatable support for the storage unit for the optical device, a moving means, a straightening means, a housing, and a guide system connected to the housing. The optical device comprises an optical fiber laterally surrounded by an inner metal tube and an outer metal tube, the outer metal tube having an outer diameter in the range of 2 mm to 8 mm and a wall thickness in the range of 0.1 mm to 0.6 mm. The housing encloses the detecting means, the storage unit for the optical device, the rotatable support for the storage unit for the optical device, the moving means, and the straightening means. The moving means is adapted to extend and retract the optical device and comprises at least one motor for driving the rotatable support for the storage unit for the optical device back and forth and a feeding means for feeding the optical device, driven by the at least one motor for driving back and forth.

[0015] Furthermore, the present invention provides a method for measuring the temperature of a molten metal bath using a measuring device according to the present invention.

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

[0017] In metallurgical installation environments, the demands for frequent and reliable temperature measurements are very high, especially when electric arc furnaces (EAFs) are used. During the processing of molten metal, various problems can occur that can affect the installed measuring devices and the measurements performed therewith. These problems include events and influences inside the metallurgical vessel, such as an inhomogeneous metal melt with unmelted parts outside the vessel, in the guide system, as well as the influence of magnetic and electric fields. During operation, the vessel containing the metal melt cannot be accessed for inspection or intervention.

[0018] It has surprisingly been found that the data quality of the measurement depends on the compatibility of the optical device with the means of movement used for moving the optical device and the respective configuration of further components of the measuring device. "Quality" in this context refers to the accuracy of the obtained measurements compared to data obtained using standard immersion thermocouples. The measuring device according to the invention has proven to be particularly suitable for unwinding and retracting optical devices having a relatively thin outer metal sheath without subjecting the optical device to tensile, frictional or bending forces.

[0019] Measurements typically involve a series of steps, during which the optical device is first moved towards and into the metal melt where the measurements are to be made, and then moved away from the metal melt at a certain speed for a certain period of time. In particular, the unwinding, rewinding and winding of the optical device, which is provided on a movably arranged storage unit, are recognized as factors that significantly affect the reliability of the obtainable data. The measurement device according to the invention allows the application of a wide range of sophisticated measurement schemes required for different situations that arise in metallurgical installations involving rapid changes between unwinding speed and direction.

[0020] In addition, the inventive arrangement of the components of the measuring device results in a device that is not demanding in terms of maintenance.

[0021] The present invention provides a measurement device for measuring the temperature of a molten metal bath.

[0022] As used herein, the term "molten metal bath" is used to describe the melt in a furnace, particularly in a vessel. An alternative term for "molten metal bath" known to those skilled in the art is "metal melt." The molten metal in 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 portion, including, for example, unmolten portions of the respective metal. The molten metal bath may be covered with a slag layer. The term "slag" refers to a non-steel by-product often produced in steelmaking furnaces and typically present as a molten material floating on top of the molten metal. Slag may include metal oxides, metal sulfides, calcium oxide, magnesium oxide, magnesite, dolomite, iron oxide, aluminum oxide, manganese oxide, silica, sulfur, phosphorus, or a combination thereof.

[0023] The temperature of the metal melt varies and typically 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.

[0024] The molten metal bath whose temperature is to be measured is located in a vessel, in particular in the vessel of an electric arc furnace.

[0025] The measuring device according to the invention comprises an optical device comprising an optical fiber laterally surrounded by an inner metal tube and an outer metal tube, i.e. at least two metal tubes laterally surround the optical fiber.

[0026] Preferably, the optical fiber is a flexible, transparent fiber. Optical fibers are most often used as a means of transmitting light, particularly in the IR wavelength range, between two ends of the fiber. Preferably, the optical fiber is formed from glass or plastic, more preferably fused silica. Preferably, the optical fiber is selected from the group consisting of graded index fiber and single mode step index fiber.

[0027] The optical fiber is laterally surrounded by an inner metal tube, and preferably the optical fiber is disposed centrally within the inner metal tube.

[0028] The inner metal tube may completely surround the optical fiber, or may be at least partially open so that the casing does not completely surround the optical fiber.

[0029] Preferably, the metal of the inner metal tube that laterally surrounds the optical fiber is iron, steel or stainless steel, especially grade 304 or 316 stainless steel.

[0030] Preferably, the inner metal tube has an outer diameter in the range of 1 mm to 3 mm. The wall thickness of the inner metal tube may be in the range of 0.1 mm to 0.3 mm.

[0031] The optical fiber is also laterally surrounded by an outer metal tube having an outer diameter in the range of 2 mm to 8 mm and a wall thickness in the range of 0.1 mm to 0.6 mm.

[0032] Preferably, the outer diameter of the outer metal tube is in the range of 2 mm to 7 mm, more preferably in the range of 3 mm to 6 mm.

[0033] Preferably, the wall thickness of the outer metal tube is in the range of 0.2 mm to 0.6 mm, more preferably in the range of 0.2 mm to 0.5 mm.

[0034] Preferably, the metal of the outer metal tube surrounding the optical fiber is iron or steel or stainless steel, especially grade 304 or 316 stainless steel.

[0035] Preferably, the inner metal tube is disposed centrally within the outer metal tube.

[0036] Preferably, the outer metal tube is not in direct contact with the inner metal tube. More preferably, the void space 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 inorganic materials, natural polymers, synthetic polymers, and combinations thereof. The gaseous material is preferably a gas or a mixture of gases. More preferably, the gas is air or an inert gas.

[0037] According to a preferred embodiment, the optical device comprises a plurality of separation elements arranged around the inner metal tube and within the outer metal tube, the separation elements forming at least one compartment between the separation elements. Here, the term "compartment" refers to the volume between different separation elements within the outer metal tube. The term "separation element" refers to a portion arranged inside the outer metal tube that subdivides the volume within the outer metal tube. Preferably, the separation element is a disk-shaped element arranged inside the outer metal tube with an opening, through which the optical fiber and the inner metal tube extend. The material of the separation element is preferably selected from the group consisting of silicone, preferably two-component silicone, rubber, leather, cork, metal, and combinations thereof.

[0038] In a preferred embodiment, the inner metal tube surrounding the optical fiber is surrounded by a further layer, which, according to certain preferred elements, comprises a plurality of pieces, preferably fibers.

[0039] 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.

[0040] Preferably, at least one additional layer comprises a non-metallic material, most preferably an organic material.

[0041] In a preferred embodiment, the linear density of the optical device 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.

[0042] It should be understood that the optical device may include any combination of the above-described features.

[0043] The total length of the optical device can be in the range of 300 m to 1000 m. As the optical device wears during the measurement, it typically shortens by 30 to 70 cm per measurement sequence during operation of the measuring device, depending on the temperature of the molten metal bath and the applied measurement protocol.

[0044] Thus, the optical device has an immersed end and an opposite end. The tip of the optical device is the tip of the immersed end of the optical device, i.e., the tip of the optical device is the end that is immersed in the molten metal bath to measure the temperature.

[0045] Preferably, when the measurement apparatus is operated, the optical device is consumed in a direction from the immersed end to the opposite end, such that after each measurement sequence, a different portion of the optical device becomes the immersed end. That is, after each measurement sequence, a new tip is generated. As used herein, the term "consumption" refers to damage to the optical device, such as melting and dissolving the optical device by and into the molten metal bath, or decomposition or combustion of the entire optical device or its different components. The opposite end can be connected to a detection means and is not consumed during measurement. In a typical measurement scenario, radiation emitted by the molten metal bath, particularly radiation in the IR wavelength range, is transmitted to the detection means by the optical fiber of the optical device. The intensity and / or spectral information of the emitted light may be processed by a processing unit connected to the detection means to obtain the temperature of the molten metal. The processing unit can be attached to a human-machine interface, such as a monitor and keyboard.

[0046] The measurement device further comprises a detection means.

[0047] The detection means is preferably coupled to the optical device, in particular to the opposite end of the optical device. The detection means may be configured to receive optical signals transmitted by the optical device, in particular optical signals in the IR wavelength range.

[0048] Preferably, the detection means is a detector, in particular a pyrometer.

[0049] The detection means may include electrical contacts, which are preferably configured to be connected to a storage unit for the optical device.

[0050] Preferably, the detection means are connected to means for converting the received signal, in particular to an analog-to-digital (AD) converter.

[0051] The detection means may further comprise a power supply means.

[0052] When the optical device and the detection means are coupled, additional means can be arranged between them, such as a mode filter or a fiber organizer.

[0053] The measurement apparatus also comprises a storage unit for the optical device.

[0054] Preferably, the storage unit for the optical device is rotationally symmetric, for example the storage unit for the optical device can be a coil, a reel, a spool, a drum or a cartridge.

[0055] The dimensions of the storage unit for optical devices can be characterized by its outer diameter and / or its circumference. Preferably, the storage unit for optical devices has an outer diameter in the range of 40 to 80 cm, more preferably in the range of 50 to 70 cm.

[0056] The storage unit for an optical device typically comprises a cylindrical core. The cylindrical core can be characterized by its outer circumference and / or its diameter. The storage unit for an optical device can also comprise additional components, such as disk-shaped or ring-shaped side panels, attached to both sides of the cylindrical core. Such panels can have the same or larger diameter as the cylindrical core, in the latter case forming a rim extending from the cylindrical core. In this case, the outer diameter of the storage unit for an optical device is larger than the diameter of the cylindrical core of the storage unit for an optical device. The panels may or may not take the form of a lattice.

[0057] Preferably, the cylindrical core of the storage unit for the optical device has a diameter in the range of 30 to 70 cm, more preferably in the range of 35 cm to 65 cm, most preferably in the range of 40 to 60 cm.

[0058] The containment unit may be hollow, i.e., may include an interior space, in other words, may include a tubular portion.

[0059] Preferably, the optical device is at least partially arranged on a storage unit for the optical device, preferably on a cylindrical core of the storage unit for the optical device. The part of the optical device arranged on the storage unit is called the wound part of the optical device. The part of the optical device not arranged on the storage unit is called the unwound part of the optical device.

[0060] During operation of the measurement apparatus, the optical device is unwound and retracted, causing portions of the optical device to unwind and rewind; in other words, the wound and unwound portions of the optical device constantly change during operation.

[0061] The unwound portion of the optical device can define an immersion path of the optical device, i.e., the "immersion path" of the optical device can be defined as the path through which each increment of the unwound portion of the optical device passes. In other words, the immersion path begins at the storage unit for the optical device and ends at the tip of the optical device. It should be understood that the immersion path is primarily determined by the components and means of the measuring device through which the optical device is guided and unwound. Preferably, the immersion path begins at the storage unit for the optical device in the housing and proceeds through the unwinding means, the straightening means, and the guide system. Thus, a first section of the immersion path is located inside the housing, and a second section of the immersion path is located outside the housing. In particular, the second section is located inside the guide system. After exiting the guide system, the immersion path can include at least one further section. During operation of the measuring device, this at least one further section can be, in particular, the section between the exit of the guide system and the position where the tip of the optical device is immersed in the molten metal bath.

[0062] Preferably, the first two sections of the immersion path are completely enclosed within the housing and guide system. In other words, the unwound portion of the optical device is completely covered by the components of the measuring device until it leaves the exit of the guide system. This provides maximum protection and control of the optical device during operation.

[0063] Preferably, the immersion path does not include any twisted sections, in other words the immersion path is curved without the presence of twists.

[0064] Preferably, the immersion path does not include a curve with a radius less than 200 times the outer diameter of the optical device. The radius of curvature is defined by the radius of an imaginary circle that best approximates the curve at a given point. Such a configuration allows for immersion of the optical device without applying excessive bending and associated forces that can lead to plastic deformation and damage.

[0065] The wound portion of the optical device can be wound and arranged on the storage unit for the optical device. In other words, the wound portion of the optical device is arranged on the storage unit for the optical device in at least one wrap, preferably multiple wraps. In such a configuration, the wound portion of the optical device comprises an inner wrap, an outer wrap, and optionally a wrap therebetween. The inner wrap may also be referred to as the first wrap, and the outer wrap may also be referred to as the last wrap. It should be understood that the diameter of the inner wrap may correspond to the diameter of the cylindrical core of the storage unit for the optical device.

[0066] Preferably, the immersion path starts at the end of the outer take-up, i.e. at the position where the optical device is no longer placed on the storage unit. Preferably, the diameter of the inner take-up of the optical device is equal to or smaller than the diameter of the outer take-up of the optical device.

[0067] Preferably, the spools of the optical device are arranged as overlapping layers on the storage unit for the optical device. Preferably, the inner layer includes the inner spool and the outer layer includes the outer spool. It may be preferable that the unwound portion of the optical device starts from the outer layer. In other words, the immersion path of the optical device starts from the outermost part of the optical device arranged on the storage unit. Therefore, when the optical device is moved along the immersion path by the moving means, the optical device is moved from the outermost position of the spooled portion of the optical device on the storage unit. This configuration ensures controlled unwinding and retraction of the optical device during operation.

[0068] In a preferred embodiment, the opposite ends of the optical device are connected to a storage unit for the optical device, in other words, the optical device has a fixed end connected to the storage unit and a free end, wherein the free end is the tip of the optical device and the fixed end is the opposite end during operation of the measuring apparatus.

[0069] It may be preferable that the storage unit for the optical device is replaceable, so that the storage unit can be replaced after the optical device has worn out during operation of the measurement apparatus.

[0070] The storage unit for the optical device may comprise the detection means, in other words, the detection means is arranged on, in, or at the storage unit for the optical device. In particular, the detection means may be arranged in a hollow space of the storage unit for the optical device. In this case, it should be understood that when the storage unit is moved, the detection means is also moved. Such an arrangement further allows for a compact design of the measuring device. Furthermore, in embodiments in which the storage unit is replaceable, such an arrangement allows for calibration of the optical device and the detection means prior to installation of the storage unit for the optical device.

[0071] The storage unit for the optical device may include means for interacting with means included in the rotatable support for the storage unit, in other words, the storage unit for the optical device and the rotatable support for the storage unit for the optical device may be provided with mutually compatible means. Such means may be configured to establish a mechanical or electrical interaction between the storage unit for the optical device and the rotatable support for the storage unit. Such compatible means allow a high degree of control of the movement of the storage unit for the optical device caused by the movement of the rotatable support and, in addition, facilitate a compact design of the measurement device.

[0072] The storage unit for the optical device may comprise electrical connection means. By providing electrical connection means in the storage unit for the optical device, in particular if the storage unit for the optical device comprises detection means, the compact design of the measurement device can be further enhanced. Such electrical connection means may be configured for signal or data transfer, power supply and / or exchange with the analysis unit.

[0073] The storage unit for the optical device may comprise mechanical connection means configured to interact with mechanical connection means included in the rotatable support for the storage unit for the optical device, such mechanical connection means being configured to ensure reliable mounting of the storage unit on the rotatable support, in particular when the rotatable support is moved.

[0074] The storage unit for optical devices may also comprise locking means, i.e. means allowing locking of the storage unit on the rotatable support for storage units for optical devices. Preferably, the rotatable support for storage units for optical devices comprises locking means in such embodiments configured to interact with locking means of the storage unit for optical devices. Such interacting locking means are preferably configured to fix the storage unit on the rotatable support for storage units for optical devices.

[0075] The storage unit for the optical device may comprise an orientation setting means configured to facilitate easy and guided mounting of the storage unit for the optical device on the rotatable support for the storage unit and to ensure proper orientation of the storage unit for the optical device on the rotatable support. Preferably, the rotatable support for the storage unit comprises an orientation setting means configured to interact with the orientation setting means of the storage unit in such an instance. Such a configuration allows precise control of the movement of the storage unit for the optical device when driven by movement of the rotatable support.

[0076] Preferably, the storage unit for the optical device comprises a means for identification, which allows easy linking of information about the optical device, such as calibration or length data, stored in the storage unit for the optical device. The means for identification of the storage unit can be selected from the group comprising printed means, such as a barcode or QR code, or electronic means, such as a chip or RFID tag, a label, and combinations thereof.

[0077] The measuring apparatus may also comprise a rotatable support for the storage unit for the optical device, on which the storage unit for the optical device is mounted, this configuration requiring that the rotatable support of the storage unit is installed in a non-stationary configuration, i.e. installed so that the storage unit can move, in particular rotate.

[0078] Furthermore, the rotatable support for the storage unit for the optical device is configured to be operated by a motor. In such a configuration, it should be understood that the movement, i.e., rotation, of the rotatable support of the storage unit results in the rotation of the storage unit for the optical device. In other words, the driving of the rotatable support directly results in the driving of the storage unit for the optical device. With this configuration, the optical device can be pushed forward without being pulled out of the storage unit.

[0079] The rotatable support for the storage unit for the optical device can be formed from a single part or multiple parts. For example, the part or parts can be rod-shaped, bar-shaped, or wheel-shaped. The cross-section of the part or parts can have any geometric shape, for example, circular, oval, square, or rectangular. In a preferred embodiment, the diameter of the part or parts increases in one direction, in other words, the part or parts do not have a uniform diameter.

[0080] The rotatable support for the storage unit for the optical device can be provided with electrical connection means, which can further enhance the compact design of the measuring device.

[0081] The rotatable support for the storage unit for the optical device can include an orientation setting means configured to facilitate easy and guided mounting of the storage unit for the optical device and ensure proper orientation of the storage unit on the rotatable support, and also to ensure a stress-free connection of the electrical connection between the storage unit for the optical device and the rotatable support.

[0082] The rotatable support for a storage unit for an optical device may comprise locking means, i.e. means allowing locking of the storage unit for an optical device on the rotatable support.

[0083] The measuring device comprises a moving means adapted to unwind and retract the optical device. The moving means should be understood as a means configured to cause an active movement of the optical device. To move the optical device, a certain degree of mechanical contact between the moving means and the optical device must be established. In particular, the moving means is adapted to drive a support for the storage unit of the optical device and unwind the optical device. The moving means can also move the optical device in the opposite direction, e.g., retract. Typically, the optical device is retracted away from the molten metal bath after the measurement sequence is finished. It should be understood that the moving means moves the optical device along the immersion path. Unwinding in the sense of the present invention means movement of the optical device during operation, typically towards the molten metal bath. Retraction should be understood as movement in the opposite direction. Unwinding relates to unwinding the optical device from the storage unit, while retraction relates to winding it onto the storage unit, i.e., replacing at least a portion of the previously unwound optical device.

[0084] In particular, the moving means may be configured to move the optical device with minimal frictional or torsional forces on the optical device, and during movement, the tip of the optical device may be immersed below the surface of the molten metal bath where temperature information may be obtained.

[0085] The moving means may further be configured to adjust the payout speed of the optical device, i.e. the speed at which the optical device increments move, may be in the range of 0.1 to 5.0 m / s.

[0086] The moving means may be configured to adjust the acceleration of the optical device. The acceleration of the payout speed may be up to 25 m / s. 2 The fast acceleration allows for precise control of the extension and retraction of the optical device.

[0087] The moving means includes at least one motor for driving a rotatable support for the storage unit for the optical device back and forth.

[0088] The motor for driving the rotatable support for the storage unit for the optical device allows for efficient and controlled rotational movement of the storage unit, and the motor for driving the rotatable support for the storage unit can appropriately change the speed of the rotational movement and functions as a part of the payout speed adjustment mechanism.

[0089] At least one motor for driving the rotatable support for the storage unit may be a servo motor and / or may be provided with a servo drive to monitor the motor position.

[0090] The moving means includes a feeding means for feeding the optical device. The feeding means is driven by at least one forward / backward drive motor. The motor for driving the feeding means can appropriately change the moving speed of the optical device and is also a further part of the feeding speed adjustment mechanism.

[0091] To enable the payout, the optical device is guided through the payout means, in other words the immersion path extends through the payout means. Preferably, the payout means is in contact with the optical device.

[0092] The delivery means may be configured to move the optical device linearly, i.e. without any rotational, curving or bending movements, in other words the immersion path of the optical device is straight as it passes through the delivery means.

[0093] In a preferred embodiment, the length of the immersion path between the storage unit of the optical device and the unwinding means is in the range of 10 cm to 100 cm, thus minimizing the length of the unwound portion of the optical device on the immersion path.

[0094] At least one motor for driving the unwinding means may be configured to detect blockages on or in the immersion path.

[0095] At least one motor for driving the unwinding means may be a servo motor and / or may be provided with a servo drive to monitor the motor position.

[0096] Preferably, the payout means comprises at least one pair of opposing wheels. Preferably, the at least one pair of opposing wheels are driven by at least one motor of the payout means, i.e., all or at least one wheel is rotated by the motor. The wheels are preferably arranged to provide a compression fit with the optical device. The optical device is driven in this manner by the wheels rotating in response to the motor driving the payout means.

[0097] The wheel of the feeding means may have a circumferential groove configured to accommodate the optical device. The most appropriate shape and geometry of the wheel groove depends on the optical device to be applied for temperature measurement. Preferably, the wheel groove is U-shaped. The surface of the wheel groove may have a flat or corrugated surface. This configuration allows the optical device to be fed without slippage.

[0098] Preferably, the wheel groove has a diameter larger than the diameter of the optical device. Preferably, the wheel groove has a diameter that is at most 5% larger than the outer diameter of the optical device. It may be preferable that the depth of the wheel groove is smaller than the diameter of the optical device. Preferably, the wheel groove has a depth that is at most 5% smaller than the diameter of the optical device. Preferably, the wheel groove has a diameter that is at most 5% larger than the outer diameter of the optical device and a depth that is at most 5% smaller than the diameter of the optical device. Therefore, when a pair of such wheels are arranged in a mated or nearly mated configuration, the gap space created by the groove has an elliptical shape. In this way, the optical device is compression-fit during the extension and retraction operations.

[0099] According to a preferred embodiment, the unwinding means may comprise two or more pairs of wheels.

[0100] The two or more pairs of wheels of the payout means may have the same or different configurations.

[0101] In a preferred embodiment, at least one pair of wheels of the feeding means are spring-loaded. In other words, at least one of the wheels is fixedly mounted, and at least one other wheel, located opposite the fixed wheel, is movable and held in place by a resilient spring. The spring-loaded configuration allows optimal guidance of the optical device without applying unnecessary clamping force. Preferably, the clamping pressure applied by the spring-loaded wheels is adjustable.

[0102] The measuring apparatus may further comprise control means configured to control the operation of at least one motor for driving the rotatable support for the storage unit for the optical device back and forth and at least one motor for driving the unwinding means back and forth. In particular, the control means may be an electronic control device such as a microcontroller, a programmable logic controller (PLC) or a computer.

[0103] Preferably, the control means is configured to coordinate the operation of at least one motor for driving the rotatable support for the storage unit for the optical device back and forth and at least one motor for driving the unwinding means back and forth. Coordination in this context means that neither of the motors is driven independently. The driving does not necessarily have to be synchronized, i.e., initiated at exactly the same time. It may also be preferable for the operation of one motor to be initiated at a separate time period before the operation of the other motor. Such coordination allows for controlled unwinding and retraction of the optical device without creating uncontrolled free lengths, which could form loops or slings that could cause blockage of the immersion path or loss of precise immersion control.

[0104] Furthermore, the measuring device comprises a straightening means. The straightening means is a component that can be straightened and / or rotated only by interaction with the optical device, in particular by frictional forces. Preferably, the straightening is performed by plastic deformation of the optical device. It should be understood that the immersion path of the optical device passes through the straightening means.

[0105] Preferably, the correction means is non-motor driven. A non-motor driven correction means allows the measurement apparatus to have a minimum number of components interacting with the optical device that must be actively linked or synchronized, allowing for reliable operation of the measurement apparatus.

[0106] Preferably, the corrective means may be configured to maintain direct contact with the optical device from two opposite sides, in such a configuration the corrective means may be understood as a semi-corrective means, since typically the corrective means contacts the optical device from three or more opposite sides.

[0107] Preferably, the correction means comprises at least two wheels, preferably three or more wheels. In one embodiment, the at least two wheels are spaced apart along the immersion path of the optical device, i.e. their rotation axes do not lie on a common axis perpendicular to the immersion path.

[0108] The pair or pairs of wheels of the straightening means may have the same or different configurations.

[0109] Preferably, the straightening means is arranged on the immersion path after the moving means, in particular after the feeding means. In other words, the optical device is guided and / or moved along the immersion path through the feeding means and then through the straightening means. In this way, the optical device is actively moved only near its storage position on the storage unit.

[0110] In a preferred embodiment, the length of the immersion path between the unwinding means and the straightening means is in the range of 10 cm to 100 cm, thus minimizing the length of the unwound portion of the optical device on the immersion path.

[0111] Preferably, the wheels of the unwinding means are arranged at an angle of 70 to 90 degrees relative to the non-motorized straightening means. The angle between the two means should be understood as the angle between their central axes, each of which is perpendicular to the immersion path.

[0112] The measuring device comprises a housing. The term "housing" should be understood as an enclosure that shields its interior from external influences, disturbances which may stop the process of payout and retraction, in this case the optical device. In particular in metallurgical facilities, the surroundings can be a harsh environment, for example due to the high temperatures and ubiquitous dirt and scrap inherent in the process.

[0113] The housing encloses the detection means, the storage unit for the optical device, the rotatable support for the storage unit for the optical device, the movement means, and the straightening means. This allows for a compact design of the measurement device. The combination of this compact design and the configuration of the movement means, i.e., the active drive of the rotatable support of the storage unit coupled with the movement of the storage unit for the optical device, the actively driven payout means, and the adjacent straightening, has surprisingly been found to be essential for the controlled immersion of optical devices having a relatively thin outer metal tube.

[0114] It should be understood that the housing also covers at least a part of the optical device, in particular the wound-up part. Preferably, at least a section of the unwound part, i.e. at least a section of the immersion path, is covered by the housing.

[0115] Preferably, the housing includes at least one opening through which the optical device can be moved.

[0116] Preferably, the height of the housing corresponds to the outer diameter of the storage unit for the optical device, and is preferably in the range of 1.2 to 2 times, more preferably 1.3 to 1.8 times, the outer diameter of the storage unit for the optical device.

[0117] The housing may have a door for ease of maintenance or for safety reasons.

[0118] The housing may be thermally insulated. The housing walls may be double layered. In a preferred embodiment, the void space between the double layer housing walls is filled with a fire-resistant material.

[0119] It is envisaged that the housing will be provided with means for accommodating, for example, cooling and heating. In a preferred embodiment, the housing is climate controlled. In this way, the housing is protected from overheating, which may interfere with the extension and retraction process of the optical device. Climate control also prevents condensation from forming.

[0120] In a preferred embodiment, the housing is provided with a gas connection port, i.e. the housing can be pressurized or purged. This embodiment allows the interior of the housing to be further protected from environmental intrusion, for example dust and dirt particles.

[0121] Preferably, the housing comprises at least one cabinet.

[0122] In a preferred embodiment, the housing comprises a cabinet with a first accessible compartment for the storage unit, a rotatable support for the storage unit for the optical device, a moving means, and a straightening means, and a second compartment for the electrical equipment of the measuring device. In this way, the moving means and storage unit, and thus the rolled-up part of the optical device, are separated from the other components. The first compartment is accessible to the end user and therefore is not closed, for example, by a lock. As a result, the end user can insert or replace the storage unit for the optical device as needed.

[0123] Preferably, the second compartment containing the electrical equipment of the measuring device is closed, for example by a door lock, so that the electrical equipment is well protected and damage due to, for example, misuse is avoided.

[0124] In one embodiment, the storage unit, the rotatable support for the storage unit for the optical device and all components of the movement means are arranged in a single cabinet and are therefore not arranged in separate units. The storage unit and the components of the movement means, in particular the feeding means and the straightening means, can be arranged in different compartments of a single cabinet.

[0125] In one embodiment, the storage unit for the optical device, the rotatable support for the storage unit for the optical device, and the components of the moving means and the straightening means are arranged at least partially in different cabinets and thus in separate units, preferably connected by connecting pipes, such an arrangement allowing a modular design of the measuring device.

[0126] The measuring device according to the present invention also comprises a guide system. The guide system should be understood as a system that passively guides the optical device without actively moving or influencing the optical device. In other words, the guide system does not include a motor, a feeding means, or a correcting means. The guide system is configured to ensure that the optical device is protected from the environment as soon as it leaves the housing. The guide system serves to guide the optical device into and / or out of the molten metal bath in the vessel. It should be understood that the immersion path is conducted through the guide system and is therefore determined by the configuration and geometry of the guide system. The guide system comprises an inlet and an outlet for enabling the feeding of the optical device through the guide system.

[0127] One end of the guide system may have an immersion end in the payout direction of the immersion path. The immersion end may be located inside a vessel containing a molten metal bath. Therefore, the immersion end is preferably configured to withstand the conditions inside such a vessel. Being configured to withstand such conditions means, for example, being able to withstand the temperature of molten steel.

[0128] Preferably, the immersed end of the guide system is arranged above the molten metal bath whose temperature is to be measured, in other words the optical device is immersed in the molten metal bath from above.

[0129] Preferably, the immersion path of the optical device is first through the payout means, then through the straightening means and subsequently through the guide system.

[0130] Advantageously, the curvature of the guide system may be configured to guide the optical device without bending or twisting. In other words, the guide system guides the immersion path of the optical device in a manner that minimizes bending forces on the optical device. Preferably, the minimum radius of curvature of the guide system is greater than four times the radius of the inner take-up of the optical device on the storage unit for the optical device.

[0131] Preferably, the guide system comprises at least one section which is straight, i.e. not curved. Preferably, the last section of the guide system, i.e. the section before the exit of the guide system, is straight.

[0132] Preferably, the guide system has a circular cross section in its longitudinal direction.

[0133] Preferably, the ratio of the inner diameter of the guide system to the diameter of the outer metal tube of the optical device is less than or equal to 2, in particular this ratio is in the range of 1.2 to 1.9.

[0134] The guide system is connected to the housing, such that the optical device can be immersed without leaving uncovered portions of at least the first two sections of the immersion path.

[0135] Preferably, the guide system is connected to the housing by a connector, which allows for a modular design of the measuring device.

[0136] In a preferred embodiment, the guide system comprises at least two separate components which are separably connected to one another, such an arrangement allowing a modular construction of the measuring device and allowing for cleaning and fault protection.

[0137] Preferably, the guide system comprises at least one guide tube. If the guide system comprises two or more guide tubes, it may be preferable that the two or more guide tubes can be interconnected in a detachable manner.

[0138] In a preferred embodiment, at least one guide tube is made from metal.

[0139] Preferably, the ratio of the inner diameter of the at least one guide tube to the diameter of the outer metal tube of the optical device is less than or equal to 2, in particular this ratio is in the range of 1.2 to 1.9.

[0140] In a preferred embodiment, the inner diameter of the at least one guide tube is less than 20 mm, preferably less than 16 mm. Preferably, the inner diameter of the at least one guide tube is in the range of 4 mm to 20 mm, more preferably in the range of 4 to 18 mm.

[0141] Preferably, the minimum radius of curvature of the immersion path is greater than 10 times the inner diameter of the at least one guide tube, more preferably 30 times greater, and most preferably 50 times greater, such a ratio allows immersion of the optical device without bending.

[0142] Preferably, the minimum radius of curvature of the at least one guide tube is greater than four times the radius of the inner take-up of the optical device on the storage unit for the optical device.

[0143] Preferably, the length of at least one guide tube is not more than 200 cm, preferably not more than 100 cm.

[0144] Preferably, the guide system comprises a dosing system, in such an arrangement the dosing system comprises a final section of the immersion path of the optical device before the optical device is immersed in the molten metal bath.

[0145] The dosing system is preferably constructed from steel and / or ceramic materials.

[0146] Preferably, the dosing system ends in a straight section, i.e., the optical device does not bend before entering the molten metal bath. Thus, the optical device can be immersed into the molten metal bath along a straight immersion path and pulled back from the molten metal bath. The mechanical properties of the optical device change due to the heat to which the optical device is exposed during temperature measurement and / or the subsequent cooling. In particular, its flexibility decreases. By guiding the optical device without bending in the final section of the immersion path, permanent deformation and therefore wear, stress, and friction of the optical device, intrusion of materials present in the container, and blockage of the dosing system are avoided. Further undesired movement of the optical device is also prevented.

[0147] In a preferred embodiment, the guide system comprises at least one guide tube and a dosing system connected together. Such a configuration ensures immersion of the optical device with a minimal unprotected section of the immersion path. Preferably, the dosing system is connected to the at least one guide tube by means of a connector.

[0148] Preferably, at least one guide tube has a straight section adjacent to the input system, ie the immersion path is not curved in this section.

[0149] Preferably, the input system comprises a gas inlet which can be connected to a gas supply means so that the immersion system can be purged with gas during operation.

[0150] Preferably, the injection system includes a blowing lance. The blowing lance is a lance through which a purge gas can be injected into the vessel. This can help prevent metal, slag, and / or debris from entering the injection system. The purge gas additionally cools the blowing lance and / or optical devices within the blowing lance.

[0151] Typically, the blowing lance is straight, i.e., not curved, to guide the optical device along a linear immersion path towards the molten metal bath. The blowing lance may be manufactured in one piece. In particular, the blowing lance is arranged coaxially with the guide system and / or axially adjacent to the guide system.

[0152] In one embodiment, the end of the blowing lance, which is directed or can be directed toward the vessel and / or the molten metal bath contained therein, is realized as a Laval nozzle. This allows a purge gas flow to be introduced into the vessel at high speed and / or supersonic speed. Thus, slag covering the molten metal bath below the optical device can be displaced before and / or during immersion of the optical device. Therefore, blockage of the blowing lance and the guide system is prevented. Additionally, the optical device is cooled in the vessel, which increases its durability and allows for particularly accurate temperature measurement.

[0153] The measurement apparatus may further comprise means for determining the position of the tip of the optical device. Knowing the position of the tip of the optical device further increases the precision with which the optical device can be immersed. Particularly in measurement sequences that include several steps of extending and retracting the optical device at specific immersion rates for specific time frames, knowing the position of the tip of the optical device may be an essential input parameter to ensure high quality measurements.

[0154] Suitable means for determining the position of the tip optical device are further not limited, for example the means may be a sensing means or a cutting means. Since the position of the means within the measurement apparatus is known, the position of the tip of the optical device will also be known.

[0155] Preferably, the means for determining the position of the tip optical device is located on, in or at the guide system.

[0156] In embodiments in which the measurement apparatus comprises a control means, the control means may be configured to interact with the means for determining the position of the tip of the optical device.

[0157] The measuring device may comprise cutting means configured to cut the optical device. Cutting the optical device may be necessary if an unexpected blockage of the immersion path occurs or if a new tip of the optical device needs to be generated. Cutting may also be employed to know the position of the tip of the optical device, i.e. to identify the position of the tip of the optical device. Preferably, the cutting means is arranged on, in or at the guide system.

[0158] The measuring device may further comprise a sensing means for sensing the presence of the optical device. Detecting the presence of the optical device means detecting information about whether the optical device is present at a particular position. This can be achieved by arranging a part of the sensing means at a known fixed position within the measuring device. The sensing means may be configured in particular to detect the position of the tip of the optical device.

[0159] The sensing means may include an inductive sensor or a sensor for measuring a property of the gas flow.

[0160] In the case of a sensor for measuring the properties of a gas flow, the sensing means is configured to measure, in particular, the flow rate of the gas flow, the flow velocity of the gas flow, and / or the gas pressure within the gas flow. The gas flow is therefore used to detect the presence of the optical device. In particular, the gas flow is realized within or adjacent to the guide system, whereby the presence of the optical device affects the gas flow, for example by obstructing at least a portion of the gas flow path. By measuring the properties, the presence of the optical device can be detected. The guide system may comprise a suitable gas source. The sensing means may be located adjacent to the guide system or at a remote location and connected to a gas line. Typically, the gas line has a high temperature resistance.

[0161] In exemplary embodiments in which the measurement device comprises control means, the control means may be configured to control the sensing means. Advantageously, the control means may be configured to control operation of a motor of the movement means in cooperation with the sensing means.

[0162] In a further embodiment, the measuring device may comprise monitoring means for monitoring the movement of the optical device, for example an encoder or an inductive switch. Such monitoring means may be configured to monitor the movement of the optical device and thus allow a comparison of the intended movement with the actual movement of the optical device. Thus, any displacement of the optical device, for example due to an interruption, that cannot be detected in other ways can still be measured.

[0163] Preferably, the monitoring means is arranged behind the moving means in the direction of the immersion path. This allows particularly accurate and obstruction-free monitoring of the movement of the optical device and high immersion control. The monitoring means may be configured to monitor the distance traveled by the optical device from a known starting point. The starting point can be defined by a means for determining the position of the tip of the optical device, in particular by the position of the tip of the optical device detected by the sensing means. After position measurement, the monitoring device therefore ensures that the position of the tip is known during subsequent movements of the optical device.

[0164] In exemplary embodiments in which the measuring device comprises a control means, the control means may be configured to control the monitoring means. Preferably, the control means is configured to compare the position of the optical device detected by the monitoring means with the position detected by the servo motor of the movement means. Thus, deviations in the position of the optical device, blockages in the guide system or high wear or friction can be identified.

[0165] The measurement device may also comprise an analysis unit for data analysis.

[0166] The measurement device may also include a control panel to allow user input or adjustments, for example in the form of control features such as switches, a keyboard, or knobs. The control panel is preferably located on or in the housing.

[0167] The measurement device may include a display means capable of providing system feedback to the user. The display means is preferably located on or in the housing.

[0168] The measurement device can be installed in a particularly fixed manner. Preferably, the measurement device is configured so that it can be arranged on the outer wall of the metallurgical vessel or, if present, on a platform on the side of the vessel. If arranged on the outer wall, the measurement device may be installed on an eccentric bottom tap (EBT) platform or on the side wall of the vessel. Thus, the optical device can be moved from a stationary position into the vessel. The platform can be part of the side wall and / or can be aligned essentially horizontally. In particular, the entry point of the vessel is an opening arranged on the platform and / or aligned essentially vertically.

[0169] A further aspect of the invention is a method for measuring the temperature of a molten metal bath using a measuring device according to the invention.

[0170] The method comprises at least (i) unwinding an optical device; (ii) measuring the temperature of the molten metal bath; (iii) retracting and winding the optical device.

[0171] All features, advantages and embodiments mentioned with respect to the measuring device according to the invention also apply to the above aspects and methods of the invention, and vice versa.

[0172] Surprisingly, it has been found that winding up the optical device in conjunction with pulling back the optical device provides greater reliability when the measuring device is used, especially when the method is performed several times.

[0173] The method includes extending an optical device.

[0174] It will be understood that the unwinding step includes the operation of at least one motor for driving a rotatable support for the storage unit for the optical device and the operation of at least one motor for driving the unwinding means back and forth.

[0175] Preferably, the operation of the at least two motors of the moving means is coordinated. It may be advantageous for the operation of at least one motor for driving the rotatable support for the storage unit for the optical device back and forth to be initiated before the operation of the at least one motor for driving the unwinding means back and forth. Thus, before the unwinding means actively moves the optical device, some length of the optical device is unwound from the storage unit for the optical device. Such coordinated operation has been found to improve the accuracy and reliability of the method.

[0176] The method comprises measuring the temperature of a molten metal bath. To measure the temperature, radiation emitted by the molten metal bath and conveyed by an optical device to a detection means, in particular radiation in the IR wavelength range, is recorded. Intensity and / or spectral information of the radiation may be processed by a processing unit connected to the detection means.

[0177] During the measurement process, the optical device may be at least partially consumed.

[0178] The method includes retracting and reeling the optical device. It should be understood that reeling while reeling the device means that the length of the unwound portion of the optical device that was not consumed during the measurement process is relocated onto a storage unit for the optical device. Even if the optical device is consumed at its tip located in the molten metal bath rather than near the storage unit, the consumed length directly affects the length of the unwound portion of the optical device that can be reeled.

[0179] It will be appreciated that the retraction and winding process includes the operation of at least one motor for driving back and forth a rotatable support for a storage unit for an optical device, and the operation of at least one motor for driving back and forth an unwinding means.

[0180] Preferably, the method according to the invention is carried out more than once.

[0181] Preferably, the method further comprises at least one step of determining the position of the tip of the optical device, which may be performed by means of determining the position of the tip of the optical device placed at a specific implementation position.

[0182] Locating the tip of the optical device can be done before and / or during the step of unwinding the optical device.

[0183] The position of the tip of the optical device can be determined during and / or after the steps of retracting and winding the optical device. Preferably, the tip of the optical device is retracted to a specific implementation position. This can avoid retracting the optical device more than necessary.

[0184] The method may further comprise the further step of retracting the optical device further from the specific implementation position, stopping the retraction of the optical device, and extending the optical device again to the specific implementation position. Preferably, the speed of the retraction movement is faster than the speed of the extension movement. Such an additional step allows for accurate positioning of the optical device, in particular the tip. In particular, the additional step is advantageous when the method is performed more than once. [Brief explanation of the drawings]

[0185] The concepts underlying the present invention are explained in more detail below with reference to exemplary embodiments shown in the drawings. The features of the exemplary implementations 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 implementations.

[0186] where: [Figure 1] FIG. 1 is a schematic diagram of an expendable optical device. [Figure 2] FIG. 2 shows an exemplary installation of the measurement device. [Figure 3] FIG. 3 shows an exemplary measurement device according to the present invention. [Figure 4] FIG. 4 is a detailed view of the coil carrying the pyrometer. [Figure 5] FIG. 5 is a simplified diagram of the measurement setup showing the immersion path of the optical device and its curvature. [Figure 6A] FIG. 6A shows a possible configuration of a feeder with two pairs of rollers. [Figure 6B] FIG. 6B shows a possible configuration of the feeder wheels. [Figure 6C] FIG. 6C shows a two-wheel configuration of the feeder. [Figure 7] FIG. 7 shows the configuration of the feeder and straightener. [Figure 8A] FIG. 8A shows a possible configuration of a straightener having a linear immersion path for the optical device. [Figure 8B] FIG. 8B shows a possible configuration of a straightener having a serpentine immersion path for the optical device. [Figure 9] FIG. 9 shows the configuration of a measurement device equipped with a sensor for determining the position of the tip. [Figure 10] FIG. 10 shows an exemplary measuring device with cutting means. DETAILED DESCRIPTION OF THE INVENTION

[0187] FIG. 1 is a schematic diagram of an expendable optical device (1', 1'', 1''') that can be used in a measurement apparatus according to the present invention. Optical fibers 2', 2'', 2''' are surrounded by inner metal tubes 3', 3'', 3''' and outer metal tubes 4', 4'', 4'''. The void spaces 5', 5'', 5''' between the metal tubes can be filled with a filler material 6'', as shown in FIG. 1B. FIG. 1C shows the configuration of the optical device 1''' with a separation element 7''' positioned around the inner metal tube 3''' and inside the outer metal tube 4'''.

[0188] 2 shows an exemplary installation of a measurement device 200 on a platform 8 located in a metallurgical vessel 9 of an electric arc furnace (EAF) 10. The compact and robust design allows the entire measurement device 200 to be located close to the operating position. This location minimizes the space required for installation of the device 200 and the length of the optical device 1 during operation. The platform 8 includes a hole 14 leading to the interior of the vessel 9 to which a guide system 207 of the measurement device 200 is connected. Inside the vessel 9, the optical device 9 enters the molten metal bath 11 (not visible in the view of FIG. 2).

[0189] 3 shows an exemplary measuring apparatus 200 according to the invention in more detail. The optical device 1 arranged on the coil 201 is mounted on a rotatable support (not shown) in a housing 202. The coil 201 also carries a detector (not shown) connected to the optical device 1. Advantageously, mechanical and electrical contact is established between the support and the coil 201. The coil 201 can be replaced after operation of the measuring apparatus 200 when the optical device 1 wears out.

[0190] 4 is a detailed view of the coil 201 carrying the detection unit 301, which may comprise, for example, a pyrometer. The coil 201 has a hollow cylindrical core 302 around which the optical device 1 can be wound. The coil 201 has two side panels 303a, 303b extending from the cylindrical core 302 to ensure that the optical device 1 does not slip off the core 302. In the configuration shown, the detection unit 301 is located in the hollow part of the cylindrical core 302. The coil 201 also comprises a portion 304 which may be connected to a rotatable support, i.e., which may be mounted to or on a rotatable support.

[0191] The housing 202 also contains a feeder 203 and a straightener 204, as well as a first motor 205 for driving the coil support and a second motor 206 for driving the feeder 203. 201 Support and feeder 203 Motor for driving 205、206 causes active movement of the optical device 1 and together form a movement system. The guide system 207 is optionally connected to the housing 202 using a connector 210. The guide system 207 comprises a guide tube 208 and an input system 209, which are also optionally connected using a connector 211. The diameter of the guide system 207 must be chosen to be fairly small, ideally no more than twice the diameter of the outer diameter of the optical device 1. Such a configuration allows passive guiding of the optical device 1 without breaking or blocking the immersion path 500.

[0192] FIG. 3 also shows an exemplary metallurgical vessel 9 containing a molten metal bath 11. The measurement apparatus 200 is positioned or installed so that the optical device 1 is immersed in the molten metal bath 11 from above after exiting the guide system 207. Between the guide system outlet 212 and the surface 12 of the molten metal bath, the optical device 1 typically must travel through a high-temperature atmosphere 13 and a slag layer (not shown) covering the molten metal bath 11. Typically, the slag does not have a constant volume and occasionally foams and expands in volume during steel processing. Therefore, it may be advantageous for the injection system 209 to include a blowing lance (not shown) that is purged with a gas flow. In such a configuration, the constant purging of gas can ensure that the guide system opening 212 is not blocked by solidified slag and / or cooled droplets of molten metal. An additional benefit of the purge gas is that it keeps the guide system 207 and unused parts of the optical device 1 cool, thereby extending the life of the guide system 207 while preventing devitrification of unused optical fibers in the optical device 1. Preferably, the gas pressure is maintained between at least 2 bar and / or at most 5 bar, which facilitates sufficient cooling to maintain a non-devitrified fiber.

[0193] FIG. 5 is a simplified diagram of the measuring device 200 showing the immersion path 500 of the optical device 1 and its curvature. The immersion path should be understood as the path followed by all increments of the unwound portion of the optical device 1 until the optical device 1 is unwound from the coil 201 and enters the molten metal bath 11. The immersion path 500 of the optical device 1 starts from the coil 201, passes through the feeder 203, the straightener 204, and the guide system 207, and ends up in the molten metal bath 11 contained in the metallurgical vessel 9. The curvature can be defined by the radius of a circle 501 fitted to the immersion path 500. This characteristic radius must be selected in relation to the characteristics of the optical device 1 and the dimensions and radius of the coil 201 in which the optical device 1 is housed. If the radius is too small, the optical device will bend excessively and there is a high probability of it breaking.

[0194] Before or during immersion, the optical device 1 may be damaged or decomposed, for example, by skull formation or unmelted portions in the metal bath 11. Such factors may lead to bending and / or breakage of the optical device 1, especially when the optical device 1 is unwound at high speeds.

[0195] The configuration shown in Figure 3 shows the system during a measurement sequence, with the tip 213 of the optical device 1 immersed below the surface of the molten metal bath 12. The measurement sequence for obtaining the temperature using the apparatus 200 according to the invention comprises unwinding the optical device 1, recording the measurement signal, and retracting the optical device 1. Unwinding and retraction can involve several steps that define the speed and duration of the movement of the optical device 1 in order to obtain optimal measurement results. The exact parameters of such a measurement sequence depend, among other things, on the material of the molten metal, its temperature, and the environment of the metallurgical installation. During unwinding and retraction, the mass of the coil support and the coil 201 must be accelerated and decelerated. The greater the mass of these components, the greater the inertia during this phase.

[0196] In general, the optical device 1 is moved with its tip 213 at the immersion end towards the molten metal bath 11. Two motors 205, 206 can precisely control the payout speed of the optical device 1. Because the payout is based on a push-pull mechanism, i.e., the motor-driven storage unit 205 pushes the optical device 1 and the separate motor-driven feeder 203 pulls the optical device 1 in conjunction, the force on the outer metal tube of the optical device 1 can be minimized.

[0197] FIG. 6A shows a possible configuration of the feeder 203 having two pairs of rollers 601a, 601b. The wheels, or each pair of rollers 601a, 601b, are positioned opposite each other with the optical device 1 positioned between them during operation. The wheels are spring-loaded with an adjustable force to clamp the optical device, thereby supporting twist-free movement with minimal clamping force while contributing to straightening. FIG. 6B shows a possible configuration of the wheels. An exemplary wheel has a cylindrical U-shaped groove 602 and a corrugated surface. Typically, the wheels are positioned so that the gap space formed between the wheels through which the optical device 1 is threaded has a slightly elliptical shape, as shown in FIG. 6C. The distance between the pair of rollers 601 and the configuration of the groove shape allow for slight deformation of the outer tube of the optical device 1 during unwinding, thus enabling first straightening. FIG. 6C further shows the structural features of the wheels, namely the groove depth 603 and diameter 604.

[0198] After the feeders 203, 203′, the immersion path 500 of the optical device 1 proceeds through straighteners 204, 204′ on a straight axis with no curvature, as shown in more detail in Figure 7. Straightening of the optical device 1 ensures that any bending or twisting caused by coiled storage of the optical device 1 on the coil 201 is at least reduced or eliminated.

[0199] 8 shows possible configurations of the straightener. In FIG. 8A, the five wheels 801a', 801b', 801c', 801d', 801e' of the straightener 204'' are arranged offset relative to one another in the direction of the immersion path 500'. In the embodiment shown in FIG. 8B, the wheels 802a'', 802b'', 802c'', 802d'', 802e'' of the straightener 204''' are arranged so that the immersion path 500'' follows a serpentine line rather than a straight line.

[0200] FIG. 7 shows an arrangement of a feeder 203′ with two pairs of rollers 601 a′, 601 b′ and a straightener 204′″ with two pairs of rollers 702 a, 702 b, with respect to the immersion path 500. The feeder 203′ and the straightener 204′ are advantageously arranged at a minimum distance. Furthermore, it has been found that a perpendicular relationship between these two components results in effective straightening of the fragile optical device 1 with a minimum applied force. FIG. 7 shows such a vertical arrangement from a front view, in particular, the wheels of the rollers 601 a′, 601 b′, 702 a, 702 b of the components 203′, 204′ are arranged perpendicular to each other. This makes it possible, on the one hand, to reduce torsional bending of the optical device 1 and, on the other hand, to minimize the number of components required for efficient operation of the measuring apparatus.

[0201] After the measurement sequence, the portion of the optical device 1 immersed in the molten metal bath 11 is melted and therefore consumed. After the measurement has been made, the length of the optical device located in the high-temperature atmosphere 13 in the metallurgical vessel 9 is pulled back towards the coil 201 and can be reused for the next measurement sequence.

[0202] To obtain reliable temperature measurements, it may be desirable to measure at a nearly constant immersion depth within the molten metal bath 11. Furthermore, control of the landing point, i.e., the position on the surface 12 of the molten metal bath at which the tip 213 is immersed, is a parameter that requires control for accurate measurement results. The landing point may be shifted, for example, due to payout of the optical device 1 not being on a linear immersion path 500 or being bent, twisted, or otherwise deformed prior to immersion.

[0203] As the above description indicates, the optical device 1 is constantly unwinding and rewinding during operation of the measurement apparatus 200, requiring highly controlled and precise unwinding in both directions, potentially leaving the unwound portion of the optical device 1 vulnerable to damage. Additionally, the length, and therefore the weight, of the optical device 1 constantly changes due to wear and tear during each measurement sequence.

[0204] The configuration of the measurement apparatus 200 according to the present invention compromises the need for control and precision while minimizing the impact on the optical device 1. The length of the unwound portion of the optical device 1 is kept to a minimum level such that the optical device is almost completely covered by the components of the apparatus before immersion in the molten metal bath.

[0205] 9 shows a configuration of the measuring apparatus 200' with a sensor 901 located at the end of the guide system 207' for determining the position of the tip 213 of the optical device 1. Other positions for the sensor 901 are also possible. The additional sensor allows for a greater control of the entire apparatus 200', further increasing the accuracy of the measurement sequence and the results obtained.

[0206] FIG. 10 shows the configuration of the measuring device 200″ with a guide system 207″ equipped with cutting means 1001. Cutting the optical device 1 at a specific position makes it possible, on the one hand, to resolve any blockages that may have occurred and, on the other hand, can be used to determine the position of the tip of the optical device 1. In the illustrated embodiment, the cut part of the unwound part of the optical device 1 is pushed forward by the subsequent part of the optical device 1 moved by the measuring device 200″ and is pushed out of the guide system 207″. [Explanation of symbols]

[0207] 1, 1', 1'', 1''' Optical Device 2', 2'', 2''' optical fiber 3', 3'', 3''' inner metal tube 4', 4'', 4''' outer metal tube 5', 5'', 5''' void space 6'' filling material 7''' Separation element 8. Platform 9 Metallurgical vessels 10 Electric Arc Furnace (EAF) 11 Molten metal bath 12 Surface of molten metal bath 13. Atmosphere inside the container 14 Holes in vessel platform 200, 200', 200'' measuring device 201 Coil 202 Housing 203, 203' Feeder 204, 204', 204'', 204''' straightening machine 205 Motor for driving coil support 206 Motor for driving feeder 207, 207', 207'' guide system 208 Guide tube 209 Input System 210 Connector 211 Connector 212 Guide system exit 213 Optical Device Tips 301 Detection Unit 302 Coil Cylindrical Core 303a, 303b Coil side panels 304 Connection to a rotatable support 500, 500', 500'' immersion path 501 Circle with the radius of curvature of the immersion path 601, 601a, 601b, 601a', 601b' Feeder pair of rollers 602 Wheel groove 603 Wheel groove depth 604 Wheel groove diameter 701 Part of the immersion path between the feeder and the straightener 702a, 702b Pair of rollers of straightener 801a', 801b', 801c', 801d', 801e' Straightener wheels 802a'', 802b'', 802c'', 802d'', 802e'' straightener wheels 901 Sensor 1001 Cutting means

Claims

1. 1. A measuring device for measuring the temperature of a molten metal bath, comprising: i) an optical device; and ii) a detection means; and iii) a storage unit for said optical device; iv) a rotatable support for the storage unit for the optical device; v) means of transportation; vi) a corrective means; and vii) a housing; and viii) a guide system connected to the housing; and Equipped with the optical device comprises an optical fiber laterally surrounded by an inner metal tube and an outer metal tube; the outer metal tube has an outer diameter in the range of 2 mm to 8 mm and a wall thickness in the range of 0.1 mm to 0.6 mm; the housing encloses the detection means, the storage unit for the optical device, the rotatable support for the storage unit for the optical device, the moving means, and the correcting means; the moving means is adapted to extend and retract the optical device; and a) at least one motor for driving the rotatable support for the storage unit for the optical device back and forth; b) a means for extending said optical device, driven by at least one motor for driving it back and forth; The measuring apparatus comprises a control means configured to coordinate the movement of the at least one motor for driving the rotatable support for the storage unit for the optical device back and forth and the at least one motor for driving the extension means back and forth.

2. The measurement apparatus of claim 1 , wherein the optical device comprises a wound portion and an unwound portion, the unwound portion defining an immersion path for the optical device.

3. The measurement device of claim 2 , wherein the immersion path does not include any twisted portions.

4. 4. The measuring apparatus of claim 2, wherein the immersion path does not include any curves with a radius less than 200 times the outer diameter of the optical device.

5. 4. The measuring device according to claim 2 or 3, wherein the immersion path starts at the end of an outer take-up of the optical device on the storage unit for the optical device.

6. 3. The measuring device according to claim 1 or 2, wherein the minimum radius of curvature of the guide system is greater than four times the radius of the inner take-up of the optical device on the storage unit for the optical device.

7. 3. The measuring device according to claim 1, wherein the guide system comprises at least one guide tube.

8. 8. The measurement apparatus of claim 7, wherein the ratio of the inner diameter of the at least one guide tube to the diameter of the outer metal tube of the optical device is 2 or less.

9. 3. The measuring device according to claim 1, wherein the height of the housing is in the range of 1.2 to 2 times the outer diameter of the storage unit for the optical device.

10. The measuring apparatus according to claim 1 or 2, further comprising means for identifying the position of the tip of the optical device.

11. 3. Measuring apparatus according to claim 1 or 2, wherein the detection means is arranged on, in or at the storage unit for the optical device.

12. 3. A method for measuring the temperature of a molten metal bath using the measuring device according to claim 1 or 2, comprising at least (i) rolling out the optical device; (ii) measuring the temperature of the molten metal bath; (iii) retracting and winding the optical device; A method comprising:

13. The method of claim 12 further comprising at least one step of locating a tip of the optical device.

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