Integral electric arc furnace bottom blowing gas supply element with safety alarm structure

Abstract

The utility model discloses an integral electric arc furnace bottom blowing air supply element with a safety alarm structure. The integral electric arc furnace bottom blowing air supply element comprises a main body, an air supply capillary steel pipe, a metal air chamber, an air supply inlet pipe, a first-stage alarm steel pipe, a first-stage alarm inlet pipe, an N-stage alarm steel pipe and an N-stage alarm inlet pipe, the metal air chamber is located at the lower end of the main body, and an air supply capillary steel pipe is pre-buried in the center of the interior of the main body and is independently connected with an air supply inlet pipe outside the main body; a first-stage alarm steel pipe and an N-stage alarm steel pipe with closed ends are pre-buried in different safety height line positions in the main body according to the alarm stage number requirement, and the first-stage alarm steel pipe and the N-stage alarm steel pipe are independently connected with a corresponding first-stage alarm air inlet pipe and a corresponding N-stage alarm air inlet pipe respectively and are independent of other air supply channels. And the first-stage alarm air inlet pipe and the N-stage alarm air inlet pipe are arranged outside the main body. By adopting the integral structure, the masonry of the gas supply element is simplified, the service life of the gas supply element is prolonged, and the safety of the gas supply element is improved.

Description

Technical Field

[0001] This utility model relates to the field of electric arc furnace steelmaking technology, specifically to an integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure. Background Technology

[0002] The electric arc furnace is the core equipment in the short-process steelmaking process. The inert gas Ar (N2) blown into the bottom of the electric arc furnace stirs the molten steel, which can accelerate the flow of molten steel, promote chemical reaction, and quickly achieve uniform chemical composition and temperature of molten steel in the molten pool, thereby reducing smelting costs.

[0003] The bottom-blowing gas supply element of an electric arc furnace (EAF) is a key component for realizing the stirring function of Ar (N2) gas at the bottom of the furnace. Blowing inert gas into the molten steel enhances the stirring of the molten pool, improves the molten pool dynamics, and achieves the goals of reducing power consumption, reducing ferroalloy and electrode consumption, shortening smelting time, and improving dephosphorization, desulfurization, and decarburization efficiency. The EAF bottom-blowing gas supply element operates in a high-temperature steel environment above 1600℃ for extended periods. Firstly, during operation, ambient-temperature gas is continuously blown into the molten steel through the supply element. The large temperature difference between the top and bottom of the permeable bricks necessitates that the refractory material withstand significant temperature changes and possess excellent thermal shock resistance. Secondly, the bottom-blowing gas enters the furnace through the supply element, rises and expands continuously, forming a reflux stirring effect within a certain range. This constantly scours and rubs against the gas supply element and surrounding refractory material at the furnace bottom, causing mechanical damage. Therefore, the bottom-blowing gas supply element is required to have excellent thermal shock resistance and erosion resistance. Thirdly, electric arc furnace steelmaking mostly adopts the operation of leaving steel and slag. During the steelmaking process and operation intervals, it is impossible to observe the condition of the furnace bottom, and it is also impossible to carry out furnace repair and slag splashing protection operations like converters. Furthermore, the gas supply elements are constantly eroded during the steelmaking process. Without a safety alarm device, the safety of the furnace bottom and gas supply elements cannot be guaranteed.

[0004] Traditional prefabricated bottom-blowing gas supply components for electric arc furnaces, such as Figure 1 As shown, it is assembled from permeable core bricks, ramming material, and multiple seat bricks. The permeable core bricks are relatively small, and the ramming strength and sintering strength of the ramming material between the permeable core bricks and seat bricks limit the service life of the permeable bricks in the bottom-blown electric arc furnace. Secondly, some traditional bottom-blown gas supply elements in electric arc furnaces lack alarm devices, and the residual height cannot be measured. Prematurely shutting down the furnace to replace the gas supply elements will cause unnecessary waste; if replaced too late, when the bottom-blown gas supply element is completely corroded, it will cause a steel leakage accident. Some bottom-blown gas supply elements in electric arc furnaces use thermocouples for temperature alarms, but these alarm devices are complex to manufacture, and thermocouples are consumed in large quantities, resulting in high costs. Other bottom-blown gas supply elements in electric arc furnaces are designed with a first-level alarm at the safety height. When this alarm signal is issued, a furnace shutdown operation must be carried out; otherwise, a steel leakage accident is likely to occur, which is not conducive to production scheduling. Utility Model Content

[0005] The purpose of this invention is to provide an integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure, which is easy to construct and install. While ensuring that gas is blown into the furnace to stir the molten steel, it improves the service life of the gas supply element and enhances its safety, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure, comprising a main body, wherein the main body is provided with a gas supply capillary steel pipe, a metal gas chamber, a gas supply inlet pipe, a first-level alarm steel pipe, a first-level alarm inlet pipe, an N-level alarm steel pipe, and an N-level alarm inlet pipe; the metal gas chamber is located at the lower end of the main body, and a gas supply capillary steel pipe is pre-embedded in the center inside the main body, and the gas supply capillary steel pipe is separately connected to the gas supply inlet pipe outside the main body; according to the alarm level requirements, the main body pre-embeds first-level alarm steel pipes and N-level alarm steel pipes with closed ends at different safety height lines inside the main body, and the first-level alarm steel pipes and N-level alarm steel pipes are respectively separately connected to the corresponding first-level alarm inlet pipes and N-level alarm inlet pipes, and are independent of other gas supply channels, and the first-level alarm inlet pipes and N-level alarm inlet pipes are located outside the main body.

[0007] Preferably, the main body of the gas supply element is made primarily of high-grade electrofused large-crystal magnesia and high-purity large-flake graphite, with phenolic resin, phenolic resin combined with asphalt, or phenolic resin combined with carbon black as binders. Various composite antioxidants are used, among which high-grade electrofused large-crystal magnesia exhibits good erosion resistance, and high-purity large-flake graphite exhibits good resistance to slag erosion. By mass percentage, it includes 70-94 wt% magnesium oxide (MgO), 2-25 wt% graphite (C), 2-6 wt% phenolic resin binder, and 0-5 wt% composite antioxidant. The antioxidant can be metallic Al powder, Mg powder, Si powder, Mg-Al alloy powder, non-metallic composite B4C powder, BN powder, AlN powder, SiC powder, or Al4C3 powder, etc. Because the matrix operates in harsh environments involving high temperatures, repeated erosion, and wear, magnesia-carbon refractories require excellent oxidation resistance, thermal shock resistance, and erosion resistance. Therefore, composite oxidants are selected, including one or more of the following: metallic Al powder, Mg powder, Si powder, Mg-Al alloy powder, non-metallic composite B4C powder, BN powder, AlN powder, SiC powder, or Al4C3 powder. The phenolic resin binder in the magnesia-carbon refractories provides room-temperature strength assurance for the main body of the refractory material; thermoplastic or thermosetting phenolic resins are generally used. The antioxidants are added to improve the oxidation resistance of the magnesia-carbon refractories. The added antioxidants are preferentially oxidized before graphite, and the delayed oxidation of graphite helps maintain its excellent thermal shock resistance and erosion resistance. Due to the large working end face and volume, the integral structure is not suitable for molding with ordinary friction brick presses and requires isostatic pressing.

[0008] Preferably, the main body is one of the following shapes: cylinder, frustum, boss, ramp, cuboid, and polygonal frustum. The main body cross-section is circular with a diameter of 250-600mm, and the end face is rectangular or polygonal with a cross-sectional size ≥220mm*220mm. The external dimensions are designed according to the usage conditions. Since the gas supply element supplies gas into the furnace, the gas supply element is subjected to aggravated effects such as stirring and scouring of the molten steel caused by the gas blowing in. Since the strength of the gas supply element is higher than that of the surrounding furnace bottom ramming material, the larger the size of the gas supply element, the stronger the protection of the furnace bottom, the lower the erosion rate of the gas supply element, and the longer its service life.

[0009] Preferably, the gas supply capillary steel pipe is a steel pipe with an inner diameter of 0.5-4mm, a wall thickness of 1-2mm, and is made of heat-resistant stainless steel.

[0010] Preferably, the metal air chamber is used to connect and fix the main body to the air supply capillary steel pipe and the alarm steel pipes at all levels. The metal air chamber is a circular air chamber or designed as a square air chamber or a polyhedral air chamber according to the brick structure. The wall thickness of the metal air chamber is 8-25mm, and the material is carbon steel or stainless steel.

[0011] Preferably, the gas supply inlet pipe is used to supply gas to the gas supply capillary steel pipe and maintain a certain pressure to meet the gas pressure and flow requirements of the blowing process. The outer diameter of the gas supply inlet pipe is 10-40mm, and the wall thickness is 2-4mm. The actual size is set according to the size of the gas supply element of the electric arc furnace bottom blowing and the pipeline connection requirements. The material is carbon steel or stainless steel.

[0012] Preferably, the first-level alarm steel pipe is made of steel with an inner diameter of 1-4mm and a wall thickness of 1-2mm. The material is heat-resistant stainless steel. The height of the first-level alarm steel pipe is the minimum safe height of the main body, and it is set 250-500mm above the metal gas chamber. When the first-level alarm signal is issued, it indicates that the bottom blowing gas supply element of the electric arc furnace must be taken offline and stopped.

[0013] Preferably, the primary alarm air inlet pipe is used to supply air to the primary alarm steel pipe and maintain a certain pressure. When the gas supply element of the electric arc furnace is corroded to the alarm position, changes in pressure and flow will occur. The corresponding pressure transmitter or flow meter will input the pressure or flow value into the PLC system. According to the set pressure and flow alarm value parameters, the PLC control system will set the audible and visual alarm (such as a buzzer emitting an audible alarm) to trigger an alarm. The outer diameter of the primary alarm air inlet pipe is 6-20mm, and the wall thickness is 2-4mm. The actual size is set according to the size of the bottom blowing gas supply element of the electric arc furnace and the pipeline connection requirements.

[0014] Preferably, N ≥ 1 in the N-level alarm steel pipe, and the alarm levels are divided into 1-5 levels. In most cases, level one or two safety alarms are used, and the alarm position is at the safe height and warning height of the gas supply element. Multi-level alarms are generally made according to special requirements of steel plants. The more alarm levels there are, the more alarm gas supply pipelines the steel plant needs to configure. Generally, the length of the level two alarm steel pipe is 100-200mm longer than that of the level one alarm steel pipe. That is, the level two alarm steel pipe is 100-200mm above the safe height. When the level two alarm signal is issued, it prompts that subsequent smelting operations should pay more attention to the furnace bottom condition and the safe use of the gas supply element. Other level three, four and multi-level alarm steel pipes can be set as needed. The height can be set according to the safety warning requirements, or it can be set to increase by 100-200mm for each level.

[0015] Preferably, the N-level alarm air inlet pipe is used to supply air to the N-level alarm steel pipe and maintain a certain pressure so that when the gas supply element of the electric arc furnace is corroded to the alarm position, changes in pressure and flow will occur, and the corresponding signal will be input into the PLC system, thereby triggering the audible and visual alarm (such as a buzzer emitting an audible alarm). The outer diameter of the N-level alarm air inlet pipe is 6-20mm, and the wall thickness is 2-4mm. The actual size is set according to the size of the bottom blowing gas supply element of the electric arc furnace and the pipeline connection requirements.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] 1. This integrated bottom-blowing gas supply element for electric arc furnaces with a safety alarm structure has an internal gas supply steel pipe and a multi-stage alarm steel pipe. It alarms based on changes in gas pressure or flow rate, which is simple, easy to implement, and low in cost. The multi-stage alarm prompts operators to make reasonable production scheduling.

[0018] 2. This integrated bottom-blowing gas supply element for electric arc furnace with safety alarm structure is easy to construct and install. While ensuring that gas is blown into the furnace to stir the molten steel, it improves the service life of the gas supply element and enhances its safety. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a traditional assembled electric arc furnace bottom-blowing gas supply element;

[0020] Figure 2 This is a front view of the overall structure of Embodiment 1 of this utility model;

[0021] Figure 3 This is a top view of the overall structure of Embodiment 1 of this utility model;

[0022] Figure 4 This is a front view of the overall structure of Embodiment 2 of this utility model;

[0023] Figure 5This is a front view of the overall structure of Embodiment 3 of this utility model;

[0024] Figure 6 This is a top view of the overall structure of Embodiment 3 of this utility model;

[0025] Figure 7 This is a front view of the overall structure of Embodiment 4 of this utility model;

[0026] Figure 8 This is a top view of the overall structure of Embodiment 4 of this utility model.

[0027] In the diagram: 1. Main body; 2. Gas supply capillary steel pipe; 3. Metal gas chamber; 4. Gas supply inlet pipe; 5. First-level alarm steel pipe; 6. First-level alarm inlet pipe; 7. Second-level alarm steel pipe; 8. Second-level alarm inlet pipe; 9. Third-level alarm steel pipe; 10. Third-level alarm inlet pipe; 11. First-level alarm steel pipe and gas pipe; 12. Support frame; 13. Second-level alarm steel pipe and gas pipe. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1:

[0030] Please see Figure 2-3This embodiment provides an integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure, comprising a main body 1, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply inlet pipe 4, a primary alarm steel pipe 5, a primary alarm inlet pipe 6, a secondary alarm steel pipe 7, and a secondary alarm inlet pipe 8. The gas supply capillary steel pipe 2, the primary alarm steel pipe 5, and the secondary alarm steel pipe 7 are disposed inside the refractory material main body 1. The metal gas chamber 3 is assembled integrally with the refractory material main body 1 via the gas supply capillary steel pipe 2, the primary alarm steel pipe 5, and the secondary alarm steel pipe 7. The closed end of the alarm steel pipe is placed inside the refractory material main body 1, and the open end is connected to the alarm inlet pipe. The refractory body 1 has a frustum shape, with the upper column of the frustum having a diameter of 400mm and the lower column having a diameter of 450mm. The larger lower dimension prevents molten steel from directly flowing downwards, improving the safety of the gas supply element. There are 8 capillary steel pipes 2 for gas supply. The metal gas chamber 3 has an outer diameter of 200mm and a wall thickness of 20mm. The secondary alarm steel pipe 7 is 100mm higher than the primary alarm steel pipe 5. The air inlet pipes and alarm heights are marked with different colors: the gas supply inlet pipe 4 is painted black; the primary alarm inlet pipe 6 is painted red, with a 10mm wide red stripe painted at the corresponding safe height on the refractory body 1; the secondary alarm inlet pipe 8 is painted yellow, with a 10mm wide yellow stripe painted at the corresponding safe height on the refractory body 1. The color coating is only used to distinguish the air inlet pipes and alarm positions, including but not limited to the three colors described.

[0031] In implementation, the integrated bottom-blowing gas supply element with a two-stage alarm structure is directly installed at the bottom of the electric arc furnace. The refractory material body 1 is compacted around it with furnace bottom tamping material. The gas supply inlet pipe 4 and the first-stage alarm steel pipe 5 and second-stage alarm steel pipe 7 are respectively connected to the corresponding gas source pipes at the furnace bottom. During the steelmaking process, inert gas Ar or N2 for stirring is blown into the furnace. When the gas supply element is corroded to the alarm position of the second-stage alarm steel pipe 7, the closed end of the alarm steel pipe is melted, the gas flow rate increases sharply, and the flow meter of the valve system detects that the flow rate is greater than the alarm set value (for example, considering the possibility of a slight leak in the pipeline, the alarm value is set to 10L / min). The flow signal is input to the PLC system, and the PLC control system instructs the audible, visual, and electrical alarms (in this embodiment, a buzzer is used for audible alarm) to sound an alarm, reminding the operator to pay attention to the furnace bottom height and the safety of the furnace bottom and gas supply element in subsequent operations. When the gas supply element is corroded to the alarm position of the first-level alarm steel pipe 5, the closed end of the alarm steel pipe is melted, the gas flow rate increases sharply, and the flow meter of the valve system detects that the flow rate is greater than the alarm set value (for example, considering the case of a slight leak in the pipeline, the alarm value is set to 10L / min). The flow signal is input to the PLC system, and the PLC control system instructs the audible, visual, and electrical alarms (in this embodiment, an audible alarm is used, and the alarm is a buzzer) to sound an alarm, prompting the operator to shut down the furnace. There are generally two operating methods: one is to shut down the gas supply element, repair the furnace bottom, and not replace the entire furnace bottom; the other is to directly shut down the furnace and replace the furnace bottom and the bottom blowing gas supply element.

[0032] Compared with the prior art, the bottom-blowing gas supply element of the electric arc furnace with alarm structure provided in this embodiment has a two-level alarm element inside the base. It can serve as an early warning, indicating that the gas supply element has been used to a near safe distance, reminding operators to pay attention to the usable height of the gas supply element, to focus on the safety of the furnace bottom, to reasonably arrange the production rhythm, and to prepare in advance for the end of production of the bottom-blowing gas supply element of the electric arc furnace.

[0033] This embodiment is applied to an electric arc furnace in a special steel plant in western China. Its service life exceeds 1000 heats, synchronized with the lifespan of the furnace bottom refractory material. This allows for simultaneous replacement of the furnace bottom refractory material and bottom-blown gas supply elements when replacing the furnace bottom. Compared to the service life of approximately 400 heats for gas supply elements in traditional assembled electric arc furnaces, the service life of the integrated electric arc furnace gas supply elements is significantly improved.

[0034] Example 2

[0035] To meet the production needs of large and medium-sized electric furnaces, in Embodiment 2 of this invention, a primary alarm steel pipe 5, a secondary alarm steel pipe 7, and a tertiary alarm steel pipe 9 are provided. (See attached...) Figure 4As shown, the gas supply element includes a refractory body 1, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply inlet pipe 4, a primary alarm steel pipe 5, a primary alarm inlet pipe 6, a secondary alarm steel pipe 7, a secondary alarm inlet pipe 8, a tertiary alarm steel pipe 9, and a tertiary alarm inlet pipe 10. The gas supply capillary steel pipe 2 and the alarm steel pipes primary alarm steel pipe 5, secondary alarm steel pipe 7, and tertiary alarm steel pipe 9 are installed inside the body 1. The metal gas chamber 3 is assembled with the body 1 as a whole through the gas supply capillary steel pipe 2 and the primary alarm steel pipes 5, 7, and 9. The air intake pipes and alarm heights are marked with different colors: the air supply intake pipe 4 is painted black; the primary air intake alarm steel pipe 6 is painted red, with a 10mm wide red stripe painted on the corresponding safe height of the refractory material body 1; the secondary alarm air intake pipe 8 is painted yellow, with a 10mm wide yellow stripe painted on the corresponding safe height of the refractory material body 1; and the tertiary alarm air intake pipe 8 is painted green, with a 10mm wide green stripe painted on the corresponding safe height of the refractory material body 1. The color coating is solely for distinguishing the air intake pipes and alarm positions, and includes, but is not limited to, the three colors described.

[0036] The inner diameter of the first-level alarm steel pipe 5, the second-level alarm steel pipe 7, and the third-level alarm steel pipe 9 is 1-4mm, and the material is heat-resistant stainless steel. The first-level alarm steel pipe 5 is for safety height alarms; when a first-level alarm signal is issued, it indicates that the bottom-blowing gas supply element must be shut down. The safety height is generally set 250-500mm above the connecting metal gas chamber 3. The length of the second-level alarm steel pipe 7 is generally 100-200mm above the safety height, meaning the alarm steel pipe is 100-200mm longer than the first-level alarm steel pipe 5. When a second-level alarm signal is issued, it prompts that future smelting operations should pay closer attention to the furnace bottom condition. The third-level alarm steel pipe 9 is 100-200mm longer than the second-level alarm steel pipe 7; the installation of the third-level alarm steel pipe 9 also serves as a measurement and early warning indicator for the furnace bottom height.

[0037] Similarly, the alarm element uses an alarm steel pipe. To ensure the alarm steel pipe functions, it is designed with one end closed and the other open. The closed end is placed inside the refractory material body 1, and the open end is connected to the alarm gas supply pipe. Gas is introduced into the alarm steel pipe, and the pressure or flow rate of the gas inside the alarm steel pipe is detected by the detection element of the valve station system (not shown in the figure). The changes in the detected gas pressure or flow rate inside the alarm steel pipe are used to determine whether the bottom blowing gas supply element has been corroded to the alarm steel pipe. When the gas flow rate inside the alarm steel pipe is less than the set alarm value (for example, considering the possibility of a minor pipeline leak, the alarm value is set to 10L / min), it indicates that the bottom blowing gas supply element of the electric arc furnace has not been corroded to the alarm steel pipe. However, when the gas flow rate inside the alarm steel pipe is greater than the set alarm value (the alarm value is set to 10L / min, and the flow rate is greater than 10L / min), it indicates that the bottom blowing gas supply element of the electric arc furnace has been corroded to the alarm steel pipe, which must be taken seriously. When the alarm reaches the first-level alarm position, the furnace must be shut down as soon as possible to repair the furnace bottom and replace the gas supply element.

[0038] It is worth noting that in order to meet the production needs of large and medium-sized electric arc furnaces, four, five or more alarm steel pipes can be set up, but considering the complexity of the gas supply system, it is advisable not to exceed five levels.

[0039] Considering the harsh operating conditions of bottom-blowing gas supply components, the base material must not only be resistant to high temperatures and oxidation, but also possess good wear resistance. To ensure the dimensions and structure of the magnesia-carbon refractory body are compatible with the surrounding furnace lining bricks, in this embodiment, the magnesia-carbon refractory body is shaped like a frustum. The diameter of the safety layer cylinder is slightly larger than that of the upper working layer, which helps prevent molten steel from directly flowing downwards and avoids steel leakage accidents.

[0040] Since the alarm is triggered by detecting the gas flow rate within the alarm steel pipe, the gas inlet pipe supplying the alarm steel pipe needs to have a certain pressure. This ensures accurate and timely alarm response even if the pressure inside the inlet pipe is insufficient. Based on actual production needs, the outer diameter of the gas inlet pipe is typically 10-40mm. However, depending on the dimensions of the gas supply element, the alarm steel pipe, and the required pipe connections, the outer diameter of the alarm inlet pipe is usually 6-20mm. Alternatively, it can be designed to the required dimensions based on the valve's gas supply system piping.

[0041] Example 3

[0042] Multi-level alarms require the configuration of multi-stage air intake pipes, which increases the hardware costs of steel plants. This embodiment provides a more reliable implementation. Figure 5-6As shown, two primary alarm steel pipes 5 are symmetrically arranged. This gas supply element includes a refractory body 1, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply inlet pipe 4, symmetrically arranged primary alarm steel pipes 5, a primary alarm inlet pipe 6, a primary alarm steel pipe parallel pipe 11, and a support frame 12. The gas supply capillary steel pipe 2 and the primary alarm steel pipe 5 are located inside the body 1. The metal gas chamber 3 is assembled integrally with the body 1 via the gas supply capillary steel pipe 2 and the primary alarm steel pipe 5. The primary alarm steel pipe parallel pipe 11 is fixedly installed inside the metal gas chamber 3 via the support frame 12.

[0043] The inner diameter of the first-level alarm steel pipe 5 is 1-4mm, and the material is heat-resistant stainless steel. The first-level alarm steel pipe 5 is for safety height alarms; when the first-level alarm signal is issued, it indicates that the bottom-blowing air supply element must be disconnected and stopped. The safety height is generally set 250-500mm above the connecting metal air chamber 3. The difference in this example is that the two symmetrically distributed first-level alarm steel pipes 5 can trigger an alarm as long as one of them reaches the designated alarm height. This ensures that if there are differences in the degree of corrosion of the air supply elements, the alarm operation will be triggered when one end of the air supply element reaches the alarm height. This arrangement of the alarm steel pipes effectively avoids delayed alarms caused by different degrees of corrosion of the bottom-blowing air supply elements.

[0044] Example 4

[0045] In another, more reliable embodiment four, two primary alarm steel pipes 5 and two secondary alarm steel pipes 7 are symmetrically arranged. (See attached...) Figure 7-8 As shown, the gas supply element includes a refractory body 1, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply inlet pipe 4, symmetrically arranged primary alarm steel pipes 5, primary alarm inlet pipes 6, primary alarm steel pipe parallel pipes 11, a support frame 12, and symmetrically arranged secondary alarm steel pipes 7, secondary alarm inlet pipes 8, and secondary alarm steel pipe parallel pipes 13. The gas supply capillary steel pipe 2, primary alarm steel pipe 5, and secondary alarm steel pipe 7 are located inside the body 1. The metal gas chamber 3 is assembled with the body 1 as a whole through the gas supply capillary steel pipe 2, primary alarm steel pipe 5, and secondary alarm steel pipe 7. The primary alarm steel pipe parallel pipe 11 and the secondary alarm steel pipe parallel pipe 13 are fixedly installed in the metal gas chamber 3 through the support frame 12.

[0046] The inner diameter of the primary alarm steel pipe 5 and the secondary alarm steel pipe 7 is 1-4mm, and the material is heat-resistant stainless steel. The primary alarm steel pipe 5 is for safety height alarms; when the primary alarm signal is issued, it indicates that the bottom-blowing gas supply element must be shut down. The safety height is generally set 250-500mm above the connecting metal gas chamber 3. The secondary alarm steel pipe 7 is generally 100-200mm longer than the safety height, meaning the alarm steel pipe is 100-200mm longer than the primary alarm steel pipe. When the secondary alarm signal is issued, it prompts that future smelting operations should pay closer attention to the furnace bottom condition.

[0047] The difference in this example is that the two alarm steel pipes are symmetrically distributed. An alarm will sound as long as one of the pipes reaches its designated position. This ensures that if the corrosion levels of the air supply components differ, the alarm will be triggered as soon as one end reaches the alarm height. This placement of the alarm steel pipes effectively avoids delayed alarms caused by uneven corrosion levels in the bottom-blowing air supply components.

[0048] The results of this implementation show that using high-purity, large-crystal fused magnesia and high-purity graphite as raw materials, and adding composite antioxidants to manufacture the bottom-blowing gas supply element for the electric arc furnace, effectively improves the service life of the gas supply element and significantly reduces the furnace bottom erosion rate. By improving the structure of the gas supply element and adding an alarm steel pipe, the safety of the bottom-blowing gas supply element is enhanced. This implementation has significant advantages in improving the efficiency of electric arc furnace steelmaking, enhancing steel quality, and improving safety during the steelmaking process.

[0049] In this embodiment, thermocouples were considered for temperature alarm when selecting alarm elements. However, the alarm device requires empirical values ​​for setting the alarm temperature, and errors in these values ​​will affect the accuracy and effectiveness of the alarm. Furthermore, thermocouples and their armor have low strength, making them easily damaged when directly buried. If blind holes are pre-drilled and the thermocouples installed later, the accuracy of these holes is difficult to guarantee, increasing installation difficulty. The high probability of thermocouple damage also reduces alarm accuracy. Additionally, the destructive nature of the alarm device and the installation of multiple thermocouples result in high economic costs and sustained investment.

[0050] After comparison, this utility model selects an alarm steel pipe as the alarm device, which has the following advantages: It adopts a gas flow alarm, and the alarm steel pipe is a heat-resistant stainless steel pipe with one end closed. It is pre-embedded during the fabrication of the main body 1, with minimal deviation in position and height. The open end is welded or bonded to the alarm air inlet pipe. The air inlet element is connected to an external air supply valve system. Once the air supply element is corroded to the alarm position, the closed end melts, and the alarm steel pipe begins to supply air. The flow meter or pressure element of the valve system will then display a change in flow or pressure, triggering an alarm. The alarm accuracy is high. The initial investment cost of the external air supply system providing gas to the alarm steel pipe is close to that of a temperature alarm system, but the subsequent investment is only a few closed heat-resistant stainless steel pipes, significantly reducing the cost compared to using thermocouples.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0052] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure, comprising a main body (1), characterized in that: The main body (1) is provided with a gas supply capillary steel pipe (2), a metal air chamber (3), a gas supply inlet pipe (4), a first-level alarm steel pipe (5), a first-level alarm inlet pipe (6), an N-level alarm steel pipe, and an N-level alarm inlet pipe; the metal air chamber (3) is located at the lower end of the main body (1), and a gas supply capillary steel pipe (2) is pre-embedded in the center of the main body (1). The gas supply capillary steel pipe (2) is separately connected to the gas supply inlet pipe (4) outside the main body (1); according to the alarm level requirements, the main body (1) is pre-embedded with a first-level alarm steel pipe (5) and an N-level alarm steel pipe with closed ends at different safety height line positions inside the main body (1). The first-level alarm steel pipe (5) and the N-level alarm steel pipe are respectively separately connected to the corresponding first-level alarm inlet pipe (6) and N-level alarm inlet pipe, and are independent of other gas supply channels. The first-level alarm inlet pipe (6) and the N-level alarm inlet pipe are located outside the main body (1).

2. The integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The main body (1) is one of the following shapes: cylinder, frustum, boss, inclined platform, cuboid and polygonal frustum. The cross section of the main body (1) is circular, and the end face is rectangular or polygonal. The external dimensions are designed according to the usage conditions.

3. The integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 2, characterized in that: The metal air chamber (3) is used to connect and fix the main body (1) with the air supply capillary steel pipe (2) and the alarm steel pipes of each level. The metal air chamber (3) adopts a circular air chamber or is designed as a square air chamber or a polyhedral air chamber according to the brick structure. The wall thickness of the metal air chamber (3) is 8-25mm.

4. The integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 2, characterized in that: The gas supply inlet pipe (4) is used to supply gas to the gas supply capillary steel pipe (2) and maintain a certain pressure to meet the gas pressure and flow requirements of the blowing process.

5. The integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 2, characterized in that: The first-level alarm steel pipe (5) is made of steel pipe with an inner diameter of 1-4mm and a wall thickness of 1-2mm. The height of the first-level alarm steel pipe (5) is the minimum safe height of the main body (1).

6. The integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 2, characterized in that: The first-level alarm air inlet pipe (6) is used to supply air to the first-level alarm steel pipe (5). The outer diameter of the first-level alarm air inlet pipe (6) is 6-20mm and the wall thickness is 2-4mm.

7. The integrated bottom-blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 2, characterized in that: The outer diameter of the N-level alarm air intake pipe is 6-20mm, and the wall thickness is 2-4mm.

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