System and method for controlling immersion depth of immersion pipe of RH refining furnace in molten steel

Abstract

The invention belongs to the technical field of RH vacuum refining, and particularly relates to a system and method for controlling the immersion depth of an immersion pipe of an RH refining furnace in molten steel. An RH refining furnace dip pipe immersion molten steel depth control system comprises a steel ladle and a steel ladle jacking device, steel slag and molten steel are contained in the steel ladle, a vacuum chamber is arranged at the top of the steel ladle, a first dip pipe and a second dip pipe are arranged on the lower portion of the vacuum chamber and extend into the steel ladle, a gas blowing pipe is arranged in the first dip pipe, and a gas blowing pipe is arranged in the second dip pipe. A high-temperature camera is arranged on the upper portion of the vacuum chamber and sequentially connected with an image recognizer and a PLC through cables, and the PLC is connected with the steel ladle jacking device through a cable. According to the method, the molten steel overturns over the slag surface to form the bright surface through the contact between the lower air blowing pipe of the dip pipe and the molten steel, and the moment when the bright surface appears is taken as the mark point, so that the depth of the dip pipe of the RH vacuum refining furnace immersed in the molten steel can be accurately detected, and automatic jacking and one-key refining of the RH steel ladle can be safely and reliably realized.

Description

Technical Field

[0001] This invention belongs to the field of RH vacuum refining technology, and specifically relates to a control system and method for the immersion depth of the immersion tube in molten steel in an RH refining furnace. Background Technology

[0002] RH vacuum refining technology is an indispensable part of the refining process in modern steel enterprises, playing a crucial role in the production of high value-added products such as automotive steel, appliance steel, silicon steel, rail beam steel, and bearing steel. In recent years, steel enterprises have shown a strong demand for intelligent RH vacuum refining equipment and "one-click" production technologies.

[0003] Because the levels of molten steel and slag entering the RH station are unstable and difficult to judge, the positions of molten steel and slag in the ladle fluctuate with the immersion of the immersion tube and the changes in the vacuum level within the vacuum chamber during RH production. This makes controlling and detecting the immersion depth of the immersion tube in the RH vacuum chamber extremely difficult, currently relying solely on manual judgment by the operator. If not carefully controlled, such as the lower end of the immersion tube not being fully submerged in the molten steel, or insufficient immersion depth before vacuuming begins, backflow of molten steel and slag can easily occur. This can range from minor damage like burning out the vacuum chamber to severe damage like molten steel and slag overflowing from the ladle, further expanding the damage area.

[0004] Among them, Ou Honglin et al. applied for a patent on March 1, 2022 (application number: 202210197767.2). This invention discloses an automatic jacking device and control method for molten steel ladle in an RH vacuum refining furnace. This method mainly measures the distance between the ladle liquid level and the ladle liquid level by installing a camera and making judgments based on program conditions to achieve automatic jacking of the ladle. However, this measurement system can only identify the position of the slag surface and cannot effectively determine the actual position of the molten steel, thus failing to effectively prevent accidents such as backflow of molten steel and slag. In addition, Wang Yun et al. applied for a patent on February 23, 2022 (application number: 202210169001.3). This invention discloses an RH molten steel level detection method based on wavelet transform of jacking current. This method collects and organizes the hydraulic pump motor current data of the ladle jacking system, finds patterns, and then calculates and confirms the ladle liquid level through a series of algorithms. Because the change in current signal is not obvious when the slag is thin and the molten steel is fluid, and because there are too many interfering power sources in the steelmaking plant, the stability of the method for detecting changes in current signal is not very reliable, and accidents such as backflow of molten steel and slag cannot be avoided.

[0005] To meet the development trend of intelligent, unmanned / reduced operation of RH vacuum refining furnaces, it is urgent to study a depth control system and method for the immersion of the immersion tube into molten steel in RH vacuum refining furnaces to replace manual operation, safely and reliably realize the automatic lifting of RH ladle, and avoid accidents such as backflow of molten steel and slag. Summary of the Invention

[0006] To address the aforementioned problems, the purpose of this invention is to provide a control system and method for the immersion depth of the immersion tube in molten steel in an RH refining furnace. This device uses the contact between the air blower at the bottom of the immersion tube and the molten steel to cause the molten steel to churn and overflow the slag surface, forming a bright surface. The moment when the bright surface appears is used as a marker point, which can accurately control and detect the immersion depth of the immersion tube in molten steel in an RH vacuum refining furnace, thereby safely and reliably realizing automatic lifting of the RH ladle and "one-click refining".

[0007] The technical solution of the present invention is as follows: a control system for the immersion depth of molten steel in an RH refining furnace immersion tube, comprising a ladle and a ladle lifting device, wherein the ladle contains slag and molten steel, a vacuum chamber is provided at the top of the ladle, an immersion tube one and an immersion tube two are provided at the lower part of the vacuum chamber, the immersion tube one and the immersion tube two extend into the ladle, an air blowing pipe is provided in the immersion tube one, a high-temperature camera is provided at the upper part of the vacuum chamber, the high-temperature camera is connected in sequence to an image recognition device and a PLC controller via a cable, and the PLC controller is connected to the ladle lifting device via a cable.

[0008] The ladle lifting device is equipped with a distance sensor, which can detect the lifting height of the ladle in real time and transmit the data to the PLC controller.

[0009] The air blowing pipe includes an air inlet, a first air outlet pipe, and a second air outlet pipe. The first and second air outlet pipes are annular and fixed in the refractory material on the inner wall of the impregnated pipe. The first and second air outlet pipes are arranged in parallel. The first air outlet pipe has a plurality of first air outlet holes evenly distributed on it, and the second air outlet pipe has a plurality of second air outlet holes evenly distributed on it.

[0010] A method for controlling the immersion depth of an immersion tube in molten steel in an RH vacuum refining furnace, using an RH refining furnace immersion tube immersion depth control system as described above, includes the following steps: S1. During operation, the ladle lifting device is activated to control the rise and fall of the ladle containing slag and molten steel, and the immersion tubes 1 and 2 at the bottom of the vacuum chamber are immersed in the molten steel in the ladle. S2. Start the air blowing pipe at the bottom of the immersion tube to blow air. When the air blowing pipe comes into contact with the molten steel, it will cause the molten steel to churn and turn over the slag surface to form a bright surface. The moment when the bright surface appears is used as a marker point. The high-temperature camera installed at the top of the vacuum chamber captures the photo inside the vacuum chamber in real time and compares the information with the preset image in the image recognition device. The information is fed back to the PLC controller in real time. When the photo inside the vacuum chamber that meets the usage requirements appears, the PLC controller controls the ladle lifting device to complete the depth control of the immersion of the immersion tube in the molten steel in the RH vacuum refining furnace.

[0011] In step S2, the high-temperature camera captures real-time images of the vacuum chamber and compares them with preset images in the image recognizer. Specifically, the real-time images of impregnation tube one and impregnation tube two are analyzed and compared. S21: The images and colors of the initial state impregnation tube one and impregnation tube two are the same; S22: As the ladle lifting device drives the ladle to rise, the slag and molten steel enter the first and second immersion tubes. Before the molten steel comes into contact with the set position of the air blowing pipe of the first immersion tube, the images and colors of the first and second immersion tubes are the same. S23: As the ladle lifting device continues to lift the ladle, slag and molten steel enter immersion tube one and immersion tube two. The molten steel is in the state before it contacts the set position of the air blowing pipe of immersion tube one. Initially, the immersion tube shows a ring-shaped image with a black exterior and a gray interior, while immersion tube two remains completely black. At this time, the PLC controller records the lifting distance of the ladle lifting device as h3, and the distance the ladle lifting device continues to rise as h4. At this time, the immersion depth of the RH refining furnace immersion tube into the molten steel is h = h1 + h2 + h4 - h3, where h1 is the distance between the top surface of the ladle lifting device and the bottom surface of the ladle, and h2, h3, and h4 are the distances between the top surface of the ladle lifting device and the bottom surface of the ladle in steps S21, S22, and S23, respectively, obtained by the distance detection sensor on the lifting device. S24: When h reaches the pre-set lifting distance, the ascent stops. The impregnation tube initially shows a completely gray halo image, while the second impregnation tube remains completely black.

[0012] The technical advantages of this invention are as follows: 1. This invention causes the molten steel to churn and overflow the slag surface by contacting the air blowing pipe under the immersion tube, forming a bright surface. The moment when the bright surface appears is used as a marker point, which can accurately control and detect the depth of the immersion tube of the RH vacuum refining furnace into the molten steel, thereby safely and reliably realizing automatic lifting of the RH ladle and "one-click refining"; 2. This invention has a simple structure. The ladle lifting device is controlled in real time by a PLC controller, which can accurately perform the lifting and lowering operations of the ladle.

[0013] The following will provide further explanation in conjunction with the accompanying drawings. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a control system for the immersion depth of a dipping tube in an RH refining furnace into molten steel, according to the present invention.

[0015] Figure 2 This is a schematic diagram showing the change in immersion depth of the RH vacuum refining furnace impregnation tube according to the present invention.

[0016] Figure 3 This is a structural diagram of the air blowing tube of the present invention.

[0017] Reference numerals: 1-Ladle lifting device; 2-Ladle; 3-Vacuum chamber; 4-High temperature camera; 5-Image recognition device; 6-PLC controller; 7-Cable; 21-Steel slag; 22-Molten steel; 31-Immersion pipe one; 32-Immersion pipe two; 33-Air blowing pipe; 331-Air inlet; 332-First air outlet; 333-First air outlet pipe; 334-Second air outlet; 335-Second air outlet pipe. Detailed Implementation Example 1

[0018] like Figure 1 , Figure 2 As shown, an RH refining furnace immersion tube immersion depth control system includes a ladle 2 and a ladle lifting device 1. The ladle 2 contains slag 21 and molten steel 22. A vacuum chamber 3 is provided at the top of the ladle 2. An immersion tube 1 31 and an immersion tube 2 32 are provided at the lower part of the vacuum chamber 3. The immersion tube 1 31 and the immersion tube 2 32 extend into the ladle 2. An air blowing pipe 33 is provided in the immersion tube 1 31. A high-temperature camera 4 is provided at the upper part of the vacuum chamber 3. The high-temperature camera 4 is connected in sequence to an image recognition device 5 and a PLC controller 6 via a cable 7. The PLC controller 6 is connected to the ladle lifting device 1 via the cable 7.

[0019] In use, the ladle lifting device 1 is activated to control the raising and lowering of the ladle 2 containing slag 21 and molten steel 22, immersing the first immersion tube 31 and the second immersion tube 32 at the bottom of the vacuum chamber 3 into the molten steel 22 of the ladle 2; the air blowing pipe 33 at the bottom of the first immersion tube 31 is activated to blow air, and the contact between the air blowing pipe 33 and the molten steel will cause the molten steel to churn and turn over the slag surface to form a bright surface. The moment when the bright surface appears is used as a marker point. The high-temperature camera 4 installed on the top of the vacuum chamber 3 captures the photos inside the vacuum chamber 3 in real time and compares the information with the preset images in the image recognition device 5, and feeds back to the PLC controller 6 in real time. When the photos inside the vacuum chamber 3 that meet the usage requirements appear, the PLC controller 6 controls the ladle lifting device 1 to complete the depth control of the immersion of the immersion tubes into the molten steel in the RH vacuum refining furnace. This invention utilizes the contact between the air blowing pipe below the immersion tube and the molten steel to cause the steel to churn and overflow the slag surface, forming a bright surface. The moment this bright surface appears is used as a marker point to accurately control and detect the immersion depth of the immersion tube in the molten steel in the RH vacuum refining furnace. This allows for the safe and reliable automatic lifting of the RH ladle and "one-click refining." Example 2

[0020] Based on Embodiment 1, in this embodiment, preferably, the ladle lifting device 1 is equipped with a distance sensor, which can detect the lifting height of the ladle 2 in real time and transmit it to the PLC controller 6.

[0021] When this invention is used, the ladle lifting device 1 is equipped with a distance sensor, which can detect the lifting height of the ladle 2 in real time and transmit the data to the PLC controller 6. This invention has a simple structure and can accurately control the ladle lifting device in real time through the PLC controller, thereby accurately raising and lowering the ladle. Example 3

[0022] Based on Example 1 or Example 1, in this example, as Figure 3 As shown, preferably, the air blowing pipe 33 includes an air inlet 331, a first air outlet pipe 333 and a second air outlet pipe 335. The first air outlet pipe 333 and the second air outlet pipe 335 are annular and fixed in the refractory material on the inner wall of the impregnated pipe 31. The first air outlet pipe 333 and the second air outlet pipe 335 are arranged in parallel. A plurality of first air outlet holes 332 are evenly distributed on the first air outlet pipe 333 and a plurality of second air outlet holes 334 are evenly distributed on the second air outlet pipe 335.

[0023] In use, the distance between the first exhaust pipe 333 and the lower edge of the immersion tube is S2, and the distance between the first exhaust pipe 333 and the second exhaust pipe 335 is S3. Gas enters through the inlet 331 and is ejected from multiple first exhaust holes 332 evenly distributed on the first exhaust pipe 333 and multiple second exhaust holes 334 evenly distributed on the second exhaust pipe 335. Upon contact with the molten steel, the gas causes the steel to churn and overflow the slag surface, forming a bright surface. The moment when the bright surface appears is used as a marker point, allowing for accurate control and detection of the immersion depth of the immersion tube in the molten steel in the RH vacuum refining furnace. Example 4

[0024] A method for controlling the immersion depth of an immersion tube in molten steel in an RH vacuum refining furnace, using an RH refining furnace immersion tube immersion depth control system as described above, includes the following steps: S1. During operation, the ladle lifting device 1 is activated to control the rise and fall of the ladle 2 containing slag 21 and molten steel 22, and the immersion tube 1 31 and immersion tube 2 32 at the bottom of the vacuum chamber 3 are immersed into the molten steel 22 of the ladle 2. S2. Start the air blowing pipe 33 at the bottom of the immersion tube 31. When the air blowing pipe 33 comes into contact with the molten steel, it will cause the molten steel to churn and turn over the slag surface to form a bright surface. The moment when the bright surface appears is used as a marker point. The high-temperature camera 4 installed on the upper part of the vacuum chamber 3 captures the picture inside the vacuum chamber 3 in real time and compares the information with the preset image in the image recognition device 5. The information is fed back to the PLC controller 6 in real time. When the picture inside the vacuum chamber 3 that meets the usage requirements appears, the PLC controller 6 controls the ladle lifting device 1 to complete the depth control of the immersion of the immersion tube into the molten steel in the RH vacuum refining furnace.

[0025] In step S2, the high-temperature camera 4 captures real-time images of the vacuum chamber 3 and compares them with preset images in the image recognizer 5. Specifically, the real-time images of impregnation tube 1 31 and impregnation tube 2 32 are analyzed and compared. S21: The images and colors of the initial state impregnation tube 31 and impregnation tube 32 are the same; S22: As the ladle lifting device 1 drives the ladle 2 to rise, the slag 21 and molten steel 22 enter the first immersion tube 31 and the second immersion tube 32. The state before the molten steel 22 touches the air blowing pipe 33 of the first immersion tube 31 is set. The images and colors of the first immersion tube 31 and the second immersion tube 32 are the same. S23: As the ladle lifting device 1 drives the ladle 2 to continue rising, the slag 21 and molten steel 22 enter the first immersion tube 31 and the second immersion tube 32. The molten steel 22 is in the state before it contacts the air blowing pipe 33 of the first immersion tube 31 at the set position. The first immersion tube 31 begins to show a ring-shaped image with a black exterior and a gray interior, while the second immersion tube 32 remains completely black. At this time, the PLC controller 6 records the lifting distance of the ladle lifting device 1 as h3, and the distance that the ladle lifting device 1 continues to rise as h4. At this time, the immersion depth of the RH refining furnace immersion tube into the molten steel is h = h1 + h2 + h4 - h3, where h1 is the distance between the top surface of the ladle lifting device and the bottom surface of the ladle, and h2, h3, and h4 are the distances between the top surface of the ladle lifting device and the bottom surface of the ladle in steps S21, S22, and S23, respectively, obtained by the distance detection sensor on the lifting device. S24: When h reaches the pre-set lifting distance, the ascent stops, and the image of the entire gray aperture begins to appear in the first impregnation tube 31, while the second impregnation tube 32 remains completely black.

[0026] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A control system for the immersion depth of an RH refining furnace immersion tube in molten steel, characterized in that: The device includes a ladle (2) and a ladle lifting device (1). The ladle (2) contains slag (21) and molten steel (22). A vacuum chamber (3) is provided at the top of the ladle (2). An immersion tube (31) and an immersion tube (32) are provided at the bottom of the vacuum chamber (3). The immersion tube (31) and the immersion tube (32) extend into the ladle (2). An air blowing pipe (33) is provided in the immersion tube (31). A high-temperature camera (4) is provided at the top of the vacuum chamber (3). The high-temperature camera (4) is connected to an image recognition device (5) and a PLC controller (6) in sequence via a cable (7). The PLC controller (6) is connected to the ladle lifting device (1) via a cable (7).

2. The immersion depth control system for the immersion tube in molten steel in an RH refining furnace according to claim 1, characterized in that: The ladle lifting device (1) is equipped with a distance sensor, which can detect the lifting height of the ladle (2) in real time and transmit it to the PLC controller (6).

3. The immersion depth control system for the immersion tube in molten steel in an RH refining furnace according to claim 1, characterized in that: The blowing pipe (33) includes an air inlet (331), a first air outlet pipe (333), and a second air outlet pipe (335). The first air outlet pipe (333) and the second air outlet pipe (335) are annular and fixed in the refractory material on the inner wall of the impregnated pipe (31). The first air outlet pipe (333) and the second air outlet pipe (335) are arranged in parallel. The first air outlet pipe (333) has a plurality of first air outlet holes (332) evenly distributed on it, and the second air outlet pipe (335) has a plurality of second air outlet holes (334) evenly distributed on it.

4. A method for controlling the immersion depth of an immersion tube in molten steel in an RH vacuum refining furnace, using the immersion depth control system for an RH refining furnace immersion tube as described in claim 1, characterized in that: Includes the following steps: S1. During operation, the ladle lifting device (1) is activated to control the rise and fall of the ladle (2) containing slag (21) and molten steel (22), and the first immersion tube (31) and the second immersion tube (32) at the bottom of the vacuum chamber (3) are immersed in the molten steel (22) of the ladle (2); S2. Start the air blowing pipe (33) at the bottom of the immersion tube (31) to blow air. When the air blowing pipe (33) comes into contact with the molten steel, the molten steel will churn and turn over the slag surface to form a bright surface. The moment when the bright surface appears is used as a marker point. The high temperature camera (4) installed on the upper part of the vacuum chamber (3) captures the photo inside the vacuum chamber (3) in real time and compares the information with the preset image in the image recognition device (5). The information is fed back to the PLC controller (6) in real time. When the photo inside the vacuum chamber (3) that meets the usage requirements appears, the PLC controller (6) controls the ladle lifting device (1) to complete the depth control of the immersion of the immersion tube into the molten steel in the RH vacuum refining furnace.

5. The method for controlling the immersion depth of the immersion tube in molten steel in an RH vacuum refining furnace according to claim 4, characterized in that: In step S2, the high-temperature camera (4) captures real-time images of the vacuum chamber (3) and compares them with the preset images in the image recognizer (5). Specifically, the real-time images of impregnation tube one (31) and impregnation tube two (32) are analyzed and compared. S21: The images and colors of the initial state impregnation tube one (31) and impregnation tube two (32) are the same; S22: As the ladle lifting device (1) drives the ladle (2) to rise, the slag (21) and molten steel (22) enter the first immersion tube (31) and the second immersion tube (32). The molten steel (22) is in a state before it comes into contact with the air blowing pipe (33) of the first immersion tube (31) and the set position. The images and colors of the first immersion tube (31) and the second immersion tube (32) are the same. S23: As the ladle lifting device (1) drives the ladle (2) to continue rising, the slag (21) and molten steel (22) enter the first immersion tube (31) and the second immersion tube (32). The molten steel (22) is in the state before the air blowing pipe (33) of the first immersion tube (31) is set. The first immersion tube (31) begins to show a ring-shaped image with a black exterior and a gray interior, while the second immersion tube (32) remains completely black. At this time, the PLC controller (6) records the ladle. The lifting distance of the lifting device (1) is h3, and the distance that the ladle lifting device (1) continues to rise is h4. At this time, the immersion depth of the RH refining furnace immersion tube into the molten steel is h = h1 + h2 + h4 - h3, where h1 is the distance between the top surface of the ladle lifting device and the bottom surface of the ladle, and h2, h3, and h4 are the distances between the top surface of the ladle lifting device and the bottom surface of the ladle in steps S21, S22, and S23, respectively, which are obtained by the distance detection sensor on the lifting device. S24: When h reaches the lifting distance set in advance by the program, the rising stops. The first impregnation tube (31) begins to show a full gray aperture image, while the second impregnation tube (32) remains completely black.

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