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    • 专利摘要:
    METHOD AND APPARATUS FOR MEASURING THE TEMPERATURE OF A CAST METAL. The invention relates to a method for measuring the temperature of a material (metal) molten with an optical fiber fed into the molten material through a disposable guide tube, immersed in the molten material having independent feed rates. It further refers to a device and an apparatus for measuring the temperature of a molten (metal) material, whose said optical fiber is partially disposed in the disposable guide tube, where the internal diameter of the disposable guide tube is greater than the diameter external of the optical fiber, where an elastic plug is disposed at the second end of or within the disposable guide tube, where the fiberglass is fed through the elastic plug, which reduces a gap between the optical fiber and the disposable guide tube. The apparatus comprises a fiber spool and a fiber optic feed mechanism and the disposable guide tube, where the feed mechanism comprises at least two independent feed motors, for the optical fiber and the disposable guide tube.
    公开号:BR102014010207B1
    申请号:R102014010207-8
    申请日:2014-04-28
    公开日:2021-05-04
    发明作者:Guido Jacobus Neyens；Michel THYS；Frank Stevens
    申请人:Heraeus Electro-Nite International N.V.；
    IPC主号:
    专利说明:

    [001] The present invention relates to a method, a device and an apparatus for measuring the temperature of a molten material, particularly a molten metal, for example, molten steel, with an optical fiber.
    [002] The Electric Arc Furnace (EAF) process for the production of molten steel is a batch process formed from the following operations: loading the furnace of metal components, melting, refining, removing slag, emptying and recovering the furnace. Each batch of steel, called a batch, is removed from the smelter in a process called bleed and therefore a reference to the cyclical batch rate of steel production is commonly a unit of time called the bleed-on-bleed time . A modern EAF operation targets a bleed-on-bleed cycle of less than 60 minutes and is more on the order of 3540 minutes.
    [003] Many of the advances made in EAF productivity that promote fast possible bleed-on-bleed times are related to increased electrical power input (in the 350-400 kWh/t range), and alternative forms of power input (oxygen lances, oxygen burners - fuel) inside the furnace. The most advanced EAF operations consume supplemental oxygen on the order of 18-27 Nm3/t which supplies 20-32% of the total energy input. In addition, improvements to components that allow for faster oven movement have reduced the amount of time the oven remains idle. The industrial objective of EAF operators has been to maximize furnace uptime, resulting in maximum productivity in order to reduce fixed costs while at the same time gaining maximum benefit from the input of electrical power. Most of the time consumed in producing a steel batch at the EAF is in the smelting process step.
    [004] The melt period is the batch of EAF operations, and in most modern EAFs it takes place in a two-stage process. Electric energy is supplied through graphite electrodes and is the biggest contributor to the foundry operation. To melt steel scrap, a theoretical minimum of 300 kWh/t is required. To supply molten metal with a temperature above the melting point of steel requires additional energy. For typical bleed temperature requirements, the total theoretical energy required is typically in the range of 350400 kWh/t. However, EAF steelmaking is only energy efficient 55-65%, and as a result the total equivalent energy input is typically in the range of 650 kWh/t for the most modern operations with 60-65% supplied by electrical energy. , the remaining requirements met by fossil fuel combustion and the chemical oxidation energy of the refining process.
    [005] During the first metallic charge, normally an intermediate voltage bleed is selected until the electrodes can sufficiently puncture the scrap. The unfused scrap position between the electrode arc and the side wall of the casting vessel protects the furnace structure from damage so that a long arc bleed (high voltage) can be used after drilling. Approximately 15% of the scrap is smelted during the initial drilling period. Combustion of fossil fuel added through special nozzles in the kiln wall contributes to scrap heating and thermal uniformity. As the furnace atmosphere heats up, the arcing tends to stabilize, the average energy input can be increased. The long arc maximizes energy transfer to the scrap, the beginning of a liquid metal reservoir will form in the heart of the furnace. For some specific types of EAF, it is a preferred practice to start the batch casting process with a small reservoir made from the pre-batch called a "hot heel".
    [006] When enough scrap is melted to accommodate the second load volume, the loading process is repeated. Since a molten steel reservoir is generated in the furnace, chemical energy must now be supplied through various sources, such as oxygen-fuel burners and oxygen lances. Oxygen can be released directly into the bath, once the molten metal height is sufficient, and eliminate obstructive scrap.
    [007] When approaching the time when the final scrap charge is completely melted, the side walls of the furnace may be exposed to high radiation from the arc. As a result, the voltage must be reduced or the creation of a foamy slag that surrounds the electrodes. The slag layer can have a thickness of more than one meter while foaming. The bow is now burnt and will protect the oven casing. In addition, a greater amount of energy will be retained in the slag and transferred to the bath resulting in greater energy efficiency. This process will create a lot of heat in the slag layer covering the steel, resulting in temperatures that are above 200°C, higher than the temperature of steel creating a very unique and difficult environment for process control measurements for reasons explained later.
    [008] Reducing bleed-on-bleed time for a batch In many cases, and especially in modern EAF operations operating with a “hot heel”, oxygen can be blown into the bath through the entire thermal cycle. This oxygen will react with various components in the bath including aluminum, silicon, manganese, phosphorus, carbon and iron. All of these reactions are exothermic (ie they generate heat) and will supply energy to help melt the slag. The metal oxides that are formed will eventually reside in the slag.
    [009] When the final scrap load and raw materials are substantially melted, flat bath conditions are achieved. At this point, a bath temperature and chemical analysis sample will be taken to determine an approximate oxygen refining period, and a calculation of remaining on time to bleed.
    [010] Regardless of the local processing steps that may vary depending on available raw material utilization, kiln design, local operating practices, and local production economies, it is evident that many forms of energy inputs into the kiln can be employed in a variety of strategies in order to minimize bleed-on-bleed time, and improve energy efficiency when converting solid scrap, and slag components to molten steel and slag in the correct chemical composition and at the desired bleeding temperature .
    [011] As in other steelmaking processes, the bleed-on-bleed production process of an EAF is guided by mathematical models that take into account the quantity and quality of raw materials in order to predict the end point of the process given by the energy inputs and heat outputs. A listing of such variables can be found in EP 0747492. Many of the process models used to control and predict EAF performance are well known in the art. When compared to the classic blast furnace to converter steelmaking process, the variance of the raw materials used in the EAF process is much greater and as such they require constant adjustments. One of several information inputs for these models required to correct and guide the process is the molten metal temperature.
    [012] Providing the EAF operator with the best and most recent metal temperature information must meet the following requirements:
    [013] - an accurate temperature representative of the bulk metal,
    [014] - fixed immersion depth regardless of oven inclination,
    [015] - continuously or almost continuously available,
    [016] - Bath level determination for immersion depth adjustments.
    [017] Typically a molten metal temperature measurement is performed using well-known disposable thermocouples such as described in US 2993944. These thermocouples can be immersed manually by an operator with a steel pole with adapted electrical wiring and connections to carry the signal. thermocouple for proper instrumentation. Additionally, many mechanical automatic thermocouple dip systems are now used to provide thermocouple dips such as those publicly available from www.more-oxy.comor described in the literature Metzen et al., MPT International 4/2000, pp.84 .
    [018] Once the accumulation of molten metal is established, the bath temperature will slowly increase. The higher the unmelted scrap content, the lower the rate of temperature rise for a given energy input. Once all the scrap is melted, the bath temperature will rise very quickly, on the order of 35°C-70°C/minute towards the end of the process. In order to predict the end of the process, the time the metal is ready to bleed, process control models need to have temperature information that is accurate and at a high enough frequency of measurements to create a prediction of the best time to stop the various energy inputs. The measurement process using robotic immersion devices requires that an access hatch, typically the slag door, a general description appears in US 2011/0038391 and in US 7767137, is open to allow the insertion of a mechanical arm supporting a disposable thermocouple . In more modern operations, this door is also used to provide access to the furnace for oxygen-fuel burners and oxygen lances that are placed in position with a manipulator similar to that of the dip lance. More recently, several additional holes may also be provided around the circumference of the furnace casing for burners as described in US 6749661.
    [019] Opening the slag door for the purpose of obtaining the previous temperature in the process allows a large amount of air to enter the furnace. The consequences of this opening are cooling the local area and providing a source of nitrogen. During arcing, nitrogen is converted to NOx, which is an undesirable effluent from the EAF process. While it is necessary to remove the kiln slag through this opening, the use of robotic immersion equipment also using this opening to take temperatures, exposes the interior of the kiln to unnecessary ingress of nitrogen and unintentional slag removal during periods when measurements of repeated temperatures are required.
    [020] With a rapid temperature rise during the final stages of the metal refining process, the time to upgrade to a process control model under the best of circumstances cannot keep up with modern high power furnaces. Ideally, fast temperature updates during the end of refining and continuous temperature information during the last few minutes before bleeding provide the best combination for model prediction accuracy and end point determination. A test-to-test time of 1 minute realistic for typical robotic systems limits the usefulness of point measurements of such a dynamic process. Conventional disposable thermocouples and robotic immersion equipment suffer from several additional limitations in addition to a low sampling frequency that ultimately reduces the anticipated success of process models when used for accurate outcome decisions.
    [021] During the smelting and refining processes, the bath will have a temperature gradient, while the bath surface will have a temperature significantly higher than that of the molten metal in bulk. Metal hot and cold spots are located throughout the interior of the furnace necessitating the use of special burners and directional fossil fuel heaters to help homogenize the interior. As stated in EP 1857760, a cold spot is in the area of the slag door where immersion of disposable thermocouples typically occurs due to the high access requirements of typical robotic immersion equipment. An EAF has the ability to rotate the oven, i.e. tilt the horizontal position of the oven, from front to back, in order to further homogenize the bath, remove slag and bleed the oven, as described in US 2886617.
    [022] Most robotic dipping devices are mounted in the slag door area and are mounted on the operating floor and thus do not tilt through the inclined furnace angle. Because of this, these manipulators cannot place disposable thermocouples inside the bath at all times, and under all circumstances. Furthermore, the immersion depth of the thermocouple is linked to the articulation of the mechanical arm of the robotic device and as such cannot easily adjust to a bath level change due to the angle of inclination of the oven. Insofar as it is important to repeatedly measure at a location that reflects the mass temperature for the purpose of EAF process operating models, actual temperature measurements taken with a manual or automatic boom show difficulties for stable immersion depths, not available as long as the position of the dip boom is not aligned with the oven swing and the actual bath level, and not in a location conducive to temperature accuracy.
    [023] The present invention measures the temperature in a metallurgical vessel using a consumable optical fiber immersed in molten metal and immersion equipment capable of inserting a temperature device through the sidewall of an EAF at a predicted cast steel immersion depth with a temperature-to-temperature measurement frequency of less than 20 seconds. The ability to experiment on demand, singly or in rapid succession allows for a measurement strategy that can update a mathematical model predicted for EAF operations at key moments during the process with the ability to measure in rapid succession providing near-continuous temperature data to a low cost.
    [024] There are prior art temperature measuring devices installed in a variety of steel fabrication containers that use permanent optical light guides to focus the radiation to the optical detectors. Examples of such prior art can be found in JP-A-61-91529, JP-A-62-52423, US 4468771, US 5064295, US 6172367, US 6923573, WO 98/46971 and WO 02/48661. The similarity to this prior art is that optical guides are permanent, and because of this need to be protected from damage using complicated installations. These protective means may comprise purging gas to cool the assembly or remove metal from physical contact with the optical element, protective sheath layers that are relatively permanent or slightly eroded with the coating of the steel forming vessel, and complicated length emissivity correction (s) of light wave and intensity in order to determine an accurate temperature.
    [025] JP-A-08-15040 describes a method that feeds a consumable optical fiber in liquid metal. Consumable optical fiber, as described in JP-A-62-19727, when immersed in a molten metal at a predicted depth, receives the radiation light emitted from the molten metal under blackbody conditions, so that the radiation intensity , using a photoelectric conversion element mounted on the opposite end of the submerged consumable optical fiber, can be used to determine the temperature of the molten metal. The prior art scientific principle concisely detailed in P Clymans, "Applications of an immersion-type optical fiber pyrometer", is that the optical fiber must be immersed to a depth to obtain blackbody conditions. Continuous measurements of molten metals using consumable optical fiber and equipment necessary to feed long lengths of spiral material material to a predetermined depth are well known in the art, such as EP 0806640 and JP-B-3267122. In harsh industrial environments, where consumable optical fiber is immersed in higher temperature metals, or in the presence of metals with a slag coating, maintaining a predetermined depth during the period of time that measurement is to take place, proved difficult because to the inherent weakness in optical fiber when its temperature increases. It has become necessary to protect the fiber already covered with metal with additional protection, such as gas cooling JP-A-2000-186961, additional composite materials layered over the fiber covered with metal, EP 655613, insulation covering JP-A- 06-058816, or additional metal covers, US 5163321, and JP-B-3351120.
    [026] The above improvements for high temperature use have the disadvantage of dramatically increasing the cost of assembling consumable fiber to provide a continuous temperature reading. Although not exactly identical to conditions encountered when measuring higher temperatures in an EAF, JP-B-3351120, it is useful to have an appreciation of the speed of consumption of fiber optics. In the example described, a very complex mechanical device for feeding an optical fiber from a spiral is used. The spiral consists of metal-coated optical fiber, again covered with an additional 3mm thick stainless steel tube. The recommended calculations described for improved temperature accuracy for continuous iron temperature measurements of a blast furnace bleed stream is an amazing 500 mm/sec. The cost of fiber optics and its surrounding stainless steel outer tube are expensive to consume at your recommended feed rate.
    [027] A practical economy of continuous temperature measurements depends on consuming the least amount of fiber possible while still gaining the benefit of continuous information. Bringing optical fiber to the measurement point with the least amount of exposed fiber is described in US 5585914 and JP-A-2000-186961 where a single metal-covered fiber is fed through a permanent nozzle that could be wall mounted of the oven, and through which the gas is injected. While these devices can successfully deliver fiber to the measurement point, they become a compromise due to obstruction and ongoing maintenance. At feed mode stages, vibration is required to prevent the fiber from soldering in the nozzle. If the orifice is blocked or closes due to inadequate gas pressure, the measurement is terminated with no possibility of recovering until the nozzle is repaired, EP 0802401 addresses the problem of a blocked opening in the furnace with a series of punch rods and tubes tubes positioned on a mobile cart providing a set of tools to deal with the problems that always prevent fiber from passing through the nozzle. However, these are strategies for unlocking a closed access hole from which no measurement data can be obtained. Since these holes are blocked, there is no possibility of obtaining temperature data, which could be at critical times in the steelmaking process.
    [028] An additional problem arises for continuously fed optical fibers that further increase the measurement cost and complexity of the immersion equipment. Immersion-type optical fiber only maintains its optical quality, and thus returns an accurate temperature if it remains protected from heat and contamination or is renewed at a rate greater than its rate of degradation. The optical signal of the bath temperature is accurately obtained under blackbody conditions for the part immersed in the molten steel. However, the remaining unimmersed part above must remain a perfect light guide. At elevated temperatures, fiber optic devitrification will occur, light transmissivity will decrease, and an error in temperature as a function of decreased intensity will increase. JP-A-09-304185 and US 7891867 describe a feed rate method, where the fiber consumption rate must be greater than the devitrification rate, thereby ensuring that a fresh fiber optic surface is always available. Simple laboratory testing shows that the optical signal remains stable for a very short period, being around 1.9 sec. at temperatures below 1580°C and only 0.1 sec. while immersed at 1700°C. Although a solution for lower temperature metals, feeding fiber optics at a speed greater than the devitrification rate for high temperature testing is expensive for an optical fiber covered by simple metal. In the case of measuring high temperatures under the harsh conditions of an EAF, the extra protection methods described in the prior art are also used at the same rate as fiber optics. This becomes prohibitively expensive for the double covered optical fibers mentioned above.
    [029] The present invention works away from the previous teaching preferring to provide a point measurement rather than a continuous measurement. A low-cost solution is devised for temperature measurements suitable to be used at a sampling frequency high enough to satisfy the demands of updating the mathematical models of the EAF casting process while solving the problems associated with immersed optical fiber in harsh environments. The present invention provides a quasi-continuous temperature measurement output comprised of immersion of the optical fiber in a molten metal through the slag covering without first contacting the slag, maintaining a predetermined immersion depth during the controlled feed measurement period, protecting the non-immersed part against devitrification in the high ambient heat of the interior of the EAF, remove and rewind the unused fiber after measurement, measure the bath level when rewinding and an immersion equipment to repeat the measurement processes always duplicating the starting conditions initials.
    [030] The problem solved by the invention is to improve the known methods and devices. Providing the EAF operator with the best and most recent molten metal temperature information must meet the following requirements:
    [031] - an accurate temperature representative of the bulk metal,
    [032] - fixed immersion depth regardless of oven inclination,
    [033] - continuously or almost continuously available,
    [034] - Bath level determination for immersion depth adjustments.
    [035] The method for measuring the temperature of a molten material, particularly molten metal, with an optical fiber, is characterized by the fact that the optical fiber is fed into the molten material through a disposable guide tube, and where the fiber The optics and a dip end of the disposable guide tube are immersed in the molten material having a feed speed where both feed speeds are independent of each other. Preferably in a first stage of immersion, the disposable guide tube and the optical fiber are immersed in the molten material, and in a second stage the optical fiber is immersed with greater velocity and deeper into the molten material than the disposable guide tube. It is preferred that the second stage starts after the dip end of the disposable guide tube is immersed in the molten material. Additionally, it is preferred that in a third stage of dipping the optical fiber is interrupted or withdrawn from the molten material, it is advantageous that, subsequent to the third stage, the outer disposable guide tube is ejected into the molten material.
    [036] In a favorable embodiment of the invention, the speed of the disposable guide tube and/or optical fiber is varying during immersion. Additionally, it is favorable that the optical fiber and the disposable guide tube are moved with unequal speed, it is advantageous that in addition to the temperature, also the upper surface of the molten material is determined.
    [037] The device of the invention for measuring the temperature of a molten material, particularly of molten metal, comprising an optical fiber and a disposable guide tube, having a dip end and a second end, opposite the dip end, is characterized in that the optical fiber is partially disposed in the disposable guide tube, where the inner diameter of the disposable guide tube is greater than the outer diameter of the optical fiber, where the elastic plug is disposed at the second end of or within the tube. a disposable guide tube, where the optical fiber is fed through the elastic plug and where the elastic plug reduces a gap between the optical fiber and the disposable guide tube. Preferably, the space area is reduced to less than 2 mm2, more preferably less than 1 mm2.
    [038] The invention is also related to an apparatus for measuring the temperature of a material cast with an optical fiber, particularly of a molten metal, comprising a device as described above, comprising an optical fiber and a disposable guide tube, having a dipping end and a second end, opposite the dipping end, where the optical fiber is partially disposed in the disposable guide tube, where the inner diameter of the disposable guide tube is greater than the outer diameter of the optical fiber, where an elastic plug is disposed at the second end of or within the disposable guide tube, where the optical fiber is fed through the elastic plug and where the elastic plug reduces the space between the optical fiber and the disposable guide tube, further comprising a fiber coil and a feed mechanism for feeding the optical fiber and the disposable guide tube, where the feed mechanism comprises at least two feed motors independent, one to feed the optical fiber and one to feed the disposable guide tube. Preferably, the apparatus is characterized in that the feed motors are combined with a separate speed control.
    [039] Additionally, the invention is related to a method of using an apparatus as described above in a method as defined by the preceding description.
    [040] The invention is used to obtain temperature measurements necessary to control the final processing steps of steel formation in an EAF. To be useful for this purpose, the device must:
    [041] - provide accurate temperature measurements at a sampling frequency that provides accurate updating of the process model and operator information for bleed
    [042] - intermediate measurement provides lower cost
    [043] - a metal measurement position representative of the metal temperature
    [044] This is performed by a device:
    [045] a continuous temperature measuring element, the fiber, always connected to the instrumentation
    [046] - is always available
    [047] - no loss of availability waiting for connections
    [048] - low contact time - fast response time on metal and slag
    [049] - low cost
    [050] an external metal tube
    [051] - supports the fiber during rapid acceleration into the bath - prevents bending away from the metal
    [052] - ensures that the fiber enters the metal - prevents upward deflection for the slag
    [053] - prevents the fiber from contacting the liquid slag - avoid contamination
    [054] - keeps the non-immersed part of the fiber cold - prevents devitrification
    [055] - is a guide that retains the rectification of the removed optical fiber - prepares the fiber for new use
    [056] - is disposable - a new straight piece is used each time - guaranteed dimensions of a gas plug
    [057] - closes the tube - allows the creation of a back pressure inside the tube
    [058] - flexible to accommodate non-optimal fiber end.
    [059] Immerse the optical fiber in a steel bath over a long enough length, using a machine that:
    [060] - Mounted on an EAF sidewall
    [061] - has a cycle time of 20 sec. preferred
    [062] - monitors fiber end location at all times - directly and indirectly using encoders and position induction devices
    [063] - renews the outer tube and gas cap and positions the fiber in and through both
    [064] - Ejects used outer tube and gas plug in EAF while rewinding unused fiber
    [065] - capable of feeding + 2000 mm/sec. with almost instantaneous deceleration
    [066] - inserts fiber and outer tube into the EAF at differential speeds
    [067] - Independent reversible and reversible drive capabilities (moving in opposite directions)
    [068] - moment compensation actuators to unwind and rewind the fiber
    [069] - Remote instrumentation for temperature and bath level detection
    [070] US5585914 recognizes that feeding an intermittent optical fiber provides intermittent temperatures. When the availability of temperature on demand is sufficient to guide the metallurgical process then the requirement for continuous temperature becomes incompatible with the technical need for such data.
    [071] In the above description, a feed of 10 mm/sec. for 10 seconds with a 20 sec downtime. has been described to be suitable for the LD process. During downtime, the fiber must be vibrated to prevent the outer coating from soldering to the nozzle. During the feed and hold times, the gas is purged through the nozzle whose diameter is fixed by the OD of the outer fiber jacket at 1.8 mm and 4.2 mm. Through this nozzle flows a purged gas contained by a series of rubber plugs contained in an oil-filled housing.
    [072] EP 802401 also provides temperature readings on demand for a duration of 2-3 sec. using an optical fiber fed through a purged gas guide tube or an "extension means" for the purpose of protecting the extended (but not immersed) portion of the optical fiber. These outer tubes are not consumables. A dipping machine is equipped to cut the devitrified part of the optical fiber so a new surface is presented every 4-5 dips.
    [073] JP-B-3351120 describes a metal-covered optical fiber continuously fed with an additional consumable outer metal tube, both fed into the metal at the same time. A feeding machine is also described. The consumable protective tube of JP-B-3351120 was continuously present on the outside of the fiber as if it were an integral part of the fiber. The present invention uses a disposable outer tube separate and distinct from the optical fiber. You could not feed the outer metal tube of JP-B-3351120 without also feeding the fiber. The separation of an additional outer metal tube from the optical fiber is distinct in this invention. It also provides solutions to other problems. While EP 802401 recognizes the need for an extension tube or guide to aid fiber soaking, the guide tube does not fully extend to the metal surface. It is non-immersive and non-disposable and because of this, fiber optics are never completely safe.
    [074] In practice, we can treat it in the same way as a mouthpiece and suffer from blocking problems. In fact, the described nozzle and guide tubes have additional mechanisms to avoid blocking their material ingress openings. The prior art clearly recognizes the importance of a purge gas in preventing slag/steel from entering a nozzle through which fiber is fed. As these nozzles are non-disposable, the method for sealing the purge gas between the guide tube and the dip end are typical permanent oil seals.
    [075] In the present invention, the disposable outer tube with a disposable gas cap provides an independent system. This system can use gas expansion instead of purge gas. In EP 802401, the guide tube or extension does not contact the metal. Its open end cannot provide pressurization during heated gas expansion. In the permanent enclosed space of US 5585914, once the gas expands it may no longer provide a displacement for metal ingress. In JP-B-3351120, the space between the outer tube and the fiber is finitely long and due to gas compressibility it cannot be used to provide a heated expansion of gas at the immersion end. The uniqueness of a self-purging outer tube can only be possible with the outer tube disposal capability design. This is unique in the entire prior art. It is not obvious why the prior art has been solving problems related to maintaining a continuous measurement of a continuously fed optical fiber.
    [076] The invention is described below by way of an example.
    [077] Figure 1 shows a prior art consumable optical fiber.
    [078] Figure 2 shows the front section of a metal-coated optical fiber.
    [079] Figure 3a shows an immersion device before immersing the optical fiber.
    [080] Figure 3b shows the immersion device after immersing the optical fiber.
    [081] Figure 3c shows the immersion device according to Figure 3b with a container of different molten material such as molten metal ladle or basin.
    [082] Figure 4 shows a view of the position of the immersion end of the outer tube and the immersion end of the optical fiber during immersion.
    [083] The device is described below by way of example. Figure 1 shows prior art consumable optical fiber 10 typically employed in measuring liquid metals comprising an optical fiber, a coating covering the optical fiber and a protective metal tube covering the surface of the plastic coating. Optical fiber 10, typically a graded index multimode fiber made of quartz glass with an inner core 11, 62.5 µm diameter and an outer stainless steel coating 12, 125 µm diameter covered with a polyimide or similar material 13. The protective metal tube 14 is typically stainless steel 1.32 mm outside diameter (OD) and 0.127 mm wall thickness. Although covered optical fiber is preferred, additional embodiments where 14 and/or 13 are replaced by a single plastic material do not depart from the intended invention.
    [084] Figure 2 shows the front section 10' of a metal-coated optical fiber 10 when fed from a spool 20 through an elastic gas-retaining plug 30, affixed to the opposite dip end 50 of a guide tube External disposable 40. The fiber 10 and external disposable guide tube 40 are not in a fixed arrangement and as such can move independently of each other and thus can be independently inserted through the slag layer 51 and into the molten bath 52 at speeds different while maintaining a gas seal 31 at the opposite end. Disposable guide tube 40 is preferably low carbon steel having a wall thickness of 0.8 to 1 mm, but can be selected from a variety of metal materials as well as ceramics and glasses, cardboard and plastics or a combination of materials. In the case where the disposable guide tube 40 is selected from a material that reacts with the molten bath, it is convenient that the dipping part 50 be prepared in a manner that does not splash molten metal into the disposable guide tube 40 by applying coating, or coverings of materials known in the art for the purpose of splash reduction.
    [085] Immersing the open-end disposable external guide tube 40 into the steel, through the slag layer 51 without cap 30 will result in slag and steel ingress into this tube. Fused slag resulting from the refining process is rich in oxides such as iron oxide which is easily absorbed into the fiber optic structure. Fiber 10 fed through the outer disposable guide tube 40, containing slag and steel, will be damaged upon reaching the open end of the outer disposable guide tube 40. For the preferred outer disposable guide tube 40, 2 m long with a immersion depth of 30 cm and open at both ends, the flow of molten material into the outer disposable guide tube 40 will be 30 cm. In the case of an external closed-end disposable guide tube 40, the flow will be approximately 16 cm. This is calculated by ignoring the expansion of the enclosed air that will expand due to an increase in its temperature. Tests show that steel ingress can be minimized by reducing the air gap between the inner diameter (ID) of the outer disposable guide tube 40 and the OD of the fiber optic metal cover 10. It is highly preferred to reduce this gap to a minimum. , however, practically for tubes with an ID of 10 mm this space must be less than 2 mm2, and preferably less than 1 mm2. Tubes with a smaller ID would allow for more space due to the faster heating rate of the enclosed air.
    [086] One of the preferred aspects of the present invention is to prevent the ingress of molten material using the expansion of the gas contained in the disposable guide tube 40. The use of an elastic plug 30 to effectively seal the end opposite the immersion end of a certain quality of sealing will ensure that the gas will bubble out of the dipped end during immersion thus keeping the disposable guide tube 40 clean. Nevertheless, any means of creating excess pressure on the disposable guide tube 40 while immersing also prevents the ingress of steel such as an inner liner of a vaporous material at minimal temperatures. A prominent concept for creating a positive pressure in the outer disposable guide tube 40 is to prevent the flow and intrusion of metal, dross and other contaminants into the disposable guide tube 40 that could impede the free feeding of the optical fiber 10.
    [087] Plug 30 must be adequately elastic in order to compensate for a non-ideal fiber optic end resulting from previous immersion. In the preferred embodiment, the plug 30 is replaced with each disposable guide tube 40. Each replacement ensures a proper seal, however, this plug 30 could be constructed so as to be reused with multiple external disposable guide tubes, and replaced with one maintenance issue. The preferred location of the plug 30 at the terminal end of the outer disposable guide tube 40 is selected for ease of application. However, placing the plug 30 closer to the immersion end is equally acceptable and will provide greater excess pressure during immersion, aiding the error-free immersion of the optical fiber 10. The plug 30 design facilitates its placement at the end of the tube. of disposable guide 40, showing a bead that rests on the end of the tube. Other configurations are possible. The exact modality of the plug 30 should reflect the ease of positioning and locating its position without departing from the main purpose of the plug to restrict air leakage into the outer tube thus ensuring an internal pressure buildup.
    [088] The ingress of steel into the steel tube while immersing in the steel tube increases with:
    [089] - an increase in immersion depth
    [090] - an increase in tube length
    [091] - an increase in air space (at the other end)
    [092] - a lower bath temperature
    [093] - a thicker wall thickness
    [094] - a higher oxygen content of the steel bath
    [095] The immersion device is described in Figure 3. The machine 100 is suitably constructed and instrumented such that the mounting plug 30 for the disposable guide tube 40 is aligned so that the optical fiber 10 can be inserted through. of the plug 30 into the outer disposable guide tube 40. the outer disposable guide tube 40 and optical fiber 10 are fed at approximately 2000 mm/sec. through the sidewall of an EAF through suitable access panels 80. These panels 80 are not part of machine 100. Machine 100 has independent 100% reversible drive or feed motors 25, 45. Motor 25 drives the fiber optic and motor 45 drives disposable guide tube 40 so that the speed of the outer disposable guide tube 40 in each direction is independent of the speed of the optical fiber in each direction.
    [096] The machine 100 is capable of independently feeding optical fiber 10 into the bath at a speed less than, equal to or greater than the speed of the external disposable guide tube 40. Preferably, the optical fiber 10 is fed faster, than so that the dipping end 50 of the outer disposable guide tube 40 and the front section 10' of the optical fiber arrive at the predetermined surface of the metal at approximately the same time. Once the bath level position is reached, the outer disposable guide tube 40 is decelerated to an almost stationary position in the molten metal 52. The front section 10' of the optical fiber 10 continues to slowly move deeper into the steel in the fence. 200 mm/sec. for approximately 0.7 sec. the outer disposable guide tube 40 and optical fiber 10 are constantly moving at unequal speeds to avoid welding the two metal surfaces together solving a problem established in the prior art.
    [097] The problem of acceleration and deceleration of optical fiber 10 is more complicated than moving the external disposable guide tube 40. Optical fiber 10 is constantly unwound and rewound from a spool or spool 20 with its weight of spool being constantly changing due to fiber consumption. The feeding machine must be adapted with additional mechanical devices to avoid the elastic return effect of the coil or spool 20 itself as well as the weight of the pyrometer connected to the coil. This is solved using 2 servo motors or 25 feed motors; 45 to control fiber movement. A feed motor 25 takes care of the unwinding and rewinding of the fiber 10 and pre-feeds the fiber 10 in such a way that the feed motor 25 can accelerate very fast.
    [098] The consumable optical fiber 10 receives the radiation light emitted from the molten metal, leads to a photoelectric conversion element mounted at the opposite end of the coiled consumable optical fiber and combined with associated instrumentation measures the radiation intensity, using this to determine the metal temperature. The fiber optic spool or spool 20 and instrumentation are located at a distance from, and separate from, the EAF, but are adequately rugged to withstand the harsh conditions of the steelmaking environment. The location of the dip end of the optical fiber 10 is constantly known and monitored by machine instrumentation throughout the dip, measurement and removal parts of the dip cycle. The machine is equipped with position encoders that determine the fiber length pass and inductive switches that register the fiber end.
    [099] After the measurement is complete the consumable optical fiber 10 and the outer disposable guide metal tube 40 are withdrawn from the steel at different speeds in such a way that the optical fiber 10 remains relatively deeper in the bath. During this movement, it is able to determine the bath level due to a change in light intensity when correlated with the length of the extracted optical fiber 10 between predetermined positions. The determination of the post-measurement bath level could be determined during immersion using various techniques well described in the literature without departing from the method of the present invention.
    [0100] Since the optical fiber 10 is free from the interior of EAF at which point the direction of the outer disposable guide tube 40 is reversed towards the interior of the oven. The outer disposable guide metal tube 40 is then ejected, disposed and consumed within the oven. A new external disposable guide tube 40 and gas plug 30 are positioned to receive the optical fiber 10 for the next measurement. The remaining optical fiber 10 is rewound during removal and returned to a starting position.
    [0101] The key abilities of the invention are:
    [0102] - Precise fiber transfer and rewinding
    [0103] - fiber end detection
    [0104] - external disposable guide tube loading
    [0105] - gas cap load and position
    [0106] - guide fiber in starting position in the gas cap
    [0107] - Fully reversible drives for fiber and disposable external guide tube
    [0108] - Independent speed profiles for fiber and external disposable guide tube
    [0109] - fiber output register for level detection
    [0110] - Fixable in the oven casing for bath level tilt compensation
    [0111] The method is described by way of example of a full cycle description. This concept should lead us to operator-free control of the EAF. It is predicted that the best operation is to take multiple temperature dips in quick succession (around 5). Each soak is approximately 2 sec.; the total cycle time must be less than 20 sec. during a single heat.
    [0112] The schematic of Figure 4 provides a view of the position of the dip end 50 of the outer disposable guide tube 40 and the dip end or front section 10' of the optical fiber 10 during 2 dips of a measurement cycle. For fiber movement we track the fiber's final position.
    [0113] With the movement of the tube the position of the immersed end of the disposable guide tube 40 is indicated. Opposite the immersion end 50 of the external disposable guide tube 40 is the gas plug 30. For the purpose of this scheme, the tube external disposable guide 40 is now ready for the immersion position. The gas plug 30 is already attached to the rear end and the optical fiber 10 is inside the gas plug 30. The relative dimensions shown are for purposes of description with the absolute distances being predicted in the actual furnace size which is a variable of steel shop for steel shop.
    [0114] The starting position 1 at time 0 of the fiber within the outer metal tube assembly at 250 cm above molten metal/bath level. The starting position 1 at time 0 of the immersion end of the outer metal tube is located 150 cm above the bath level. Optical fiber 10 is fed from position 1 to 2 while outer disposable guide tube 40 remains nearly stationary. Enter the time 0.8 sec. and 1.2 sec., covering positions 2 to 4, the optical fiber 10 and outer disposable guide tube 40 advance to a location just above the molten slag 51. In 1.2 sec. and position 4, the fiber is advanced slightly faster than the outer disposable guide tube 40 passing through the slag 51 and into the molten metal 52. The outer disposable guide metal tube 40 decelerates while the optical fiber 10 advances by approximately 200 mm/sec. reaching the maximum immersion in position 6 and 1.5 sec. within the immersion. Optical fiber 10 and outer disposable guide tube 40 are withdrawn within 0.1 sec. Optical fiber 10 continues to be withdrawn and rewound back to its load position 8 while the remainder of the outer disposable guide metal tube 40 direction is inverted at position 7 and discarded. The optical fiber 10 is further protected by the remaining portion of the discarded outer disposable guide tube 40.
    权利要求:
    Claims (4)
    [0001]
    1. Method for measuring the temperature of a molten material (52) with an optical fiber (10), where the optical fiber (10) is fed into the molten material (52) through a disposable guide tube (40), and having a dip end (50) and a second end, opposite the dip end (50), the optical fiber (10) and dip end (50) of the disposable guide tube (40) being immersed in the material. cast (52), both having a feed speed where both feed speeds are independent of each other, using a fiber optic spool (20) and a feed mechanism to feed the optical fiber (10) and the disposable guide tube (40), whereby the feed mechanism is composed of at least two independent feed motors (25; 45), each combined with a separate speed control, one for feeding the optical fiber (10) and one for feeding the disposable guide tube (40), and in which an elastic plug (30) is disposed. o at the second end or within the disposable guide tube (40), the optical fiber (10) being fed through the elastic plug (30), wherein the elastic plug (30) reduces a gap between the optical fiber (10) and the disposable guide tube (40), and the internal diameter of the disposable guide tube (40) being greater than the external diameter of the optical fiber (10), characterized by the fact that, (i) in a first immersion phase , the disposable guide tube (40) and the optical fiber (10) are immersed in the molten material (52), (ii) in a second stage, the optical fiber (10) is immersed with greater speed and depth in the molten material (52) than the disposable guide tube (40), where the second stage begins after the end of the immersion of the disposable guide tube (40) is immersed in the molten material (52), and (iii) in a third stage of immersion, the optical fiber ( 10) is stopped or withdrawn from the molten material (52) where, after the third stage, the external disposable guide tube (40) is ejected into the molten material (52).
    [0002]
    2. Method according to claim 1, characterized in that the speed of the disposable guide tube (40) and/or optical fiber (10) is varying during immersion.
    [0003]
    3. Method according to any one of claims 1 or 2, characterized in that the optical fiber (10) and the disposable guide tube (40) are moved with unequal speed.
    [0004]
    4. Method according to any one of claims 1 to 3, characterized in that in addition to the temperature, the upper surface of the molten material (52) is also determined, whereby a bath level is determined as a function of a change in light intensity when correlated with the length of the optical fiber (10) extracted between certain positions.
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    同族专利:
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    US20140321504A1|2014-10-30|
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    IN2014CH02102A|2015-07-03|
    AU2014202069B2|2014-11-27|
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    JP2014219395A|2014-11-20|
    ZA201402435B|2015-03-25|
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    UA112664C2|2016-10-10|
    BR102014010207A2|2015-10-13|
    AU2014202069C1|2016-12-15|
    CN104132750A|2014-11-05|
    AU2014202069A1|2014-11-13|
    KR20140130075A|2014-11-07|
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    KR101679115B1|2016-11-23|
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    EP2799824A1|2014-11-05|
    EP2799824B1|2019-10-23|
    RU2014117695A|2015-11-10|
    TW201506366A|2015-02-16|
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    法律状态:
    2015-10-13| B03A| Publication of a patent application or of a certificate of addition of invention [chapter 3.1 patent gazette]|
    2018-11-13| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2020-03-31| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-03-30| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-05-04| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 28/04/2014, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    EP13165941.9|2013-04-30|
    EP13165941.9A|EP2799824B1|2013-04-30|2013-04-30|Method and apparatus for measuring the temperature of a molten metal|
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