Electrical control method for preventing CAS immersion cover device from being impacted and damaged by steel vehicle

Abstract

The invention relates to an electrical control method for preventing a CAS immersion cover device from being impacted and damaged by a steel vehicle, and belongs to the field of electrical control. The electrical control method is based on a converter steel car and a CAS immersion cover device electrical control system, and comprises the following steps that a command that the CAS immersion cover device does not ascend in place is added, and protection control over operation of the steel car to a CAS feeding position is participated. According to the method, the situation that the CAS dipping cover device does not ascend in place, an operator mistakenly starts the steel car to run towards a CAS feeding position, so that the dipping cover device is impacted and damaged by the steel car, the service life of the converter steel car and key equipment of the CAS dipping cover device is shortened, the running reliability and the smelting period of the converter steel car are affected, and the accident that a converter smelting system is out of control is avoided.

Description

Technical Field

[0001] This invention belongs to the field of electrical control and relates to an electrical control method for preventing damage to the CAS immersion cover device from impact by a steel vehicle. Background Technology

[0002] In existing converter ladle processing procedures, composition adjustment by sealed argon bubbling (CAS) refining, as an efficient and low-cost ladle refining method, is widely used in the process steps of composition fine-tuning, degassing, homogenization, and temperature maintenance for low- and medium-end steel grades. The CAS immersion hood device is the core component of this refining system. It achieves agitation and composition adjustment by immersing the lower hood into the molten steel in the ladle and sealing it with argon gas, while effectively reducing secondary oxidation of the molten steel and the floating of inclusions.

[0003] The converter steel car (steel ladle car) plays a crucial role in transporting the ladles of steel after tapping from the converter to the CAS refining station (argon blowing station), and then to the continuous casting or other subsequent work stations. This steel car typically employs an electrical control system with variable frequency speed control, cable reel power supply, and track limit protection. It operates over long distances at high speeds (up to 1.0–1.5 m / s in rapid forward mode) and carries a large load (a 210t ladle often weighs over 300t), making it a heavy-duty, high-inertia mobile device within a steel plant.

[0004] In actual production organization, after the steel ladle taps from the converter, it usually needs to quickly enter the CAS (Carbon Acrylic Gas Handling) position for argon blowing to shorten the smelting rhythm and improve equipment turnover rate. However, the existing electrical control system (based on PLC) generally only considers the preparation conditions of the steel car itself (such as the release of the motor emergency stop, normal brake power supply, inverter ready, cable reel ready, normal fan power supply, limit position protection, etc.) as the interlocking conditions for forward operation, without incorporating the rising position signal of the CAS immersion hood lifting device into the safety protection interlock for the steel car to run to the CAS feeding position (refining position).

[0005] This design flaw has revealed significant safety hazards in actual operation: After CAS refining, the impregnation hood needs to be raised to its highest position (upper limit position) to detach from the space above the ladle, making way for the ladle car to enter and leave the CAS position. If the operator misjudges that the hood has been raised before the impregnation hood is fully raised (the upper limit contact is not reliably closed), or if the operator issues a command for the ladle car to move forward quickly due to delayed on-site signal feedback, misoperation, or other reasons, the heavily loaded ladle car is very likely to have a hard collision with the impregnation hood, which is still in a lower position.

[0006] Such collisions can have very serious consequences:

[0007] This directly leads to severe deformation, breakage, or even complete scrapping of key components such as the CAS immersion hood body, lifting mechanism, sealing flange, water-cooled parts, and argon pipeline, resulting in long repair cycles and high costs. This could cause damage to the ladle car body, tracks, and limit devices, affecting the operational reliability of the entire converter-ladle transportation system. In extreme cases, this can cause molten steel to slosh, overflow, or interrupt subsequent refining, severely disrupting the smelting rhythm, prolonging the smelting cycle, and reducing the daily output capacity of the converter. If the collision occurs when the molten steel is at a high temperature or during a critical stage of composition adjustment, it may also induce secondary accidents such as molten steel splashing, increased entrapment of inclusions, or even localized molten steel blasting, threatening the personal safety of on-site workers.

[0008] In recent years, with the increasing size of converters (200-300t class) and the demand for high-paced production, ladle turnaround time has been continuously compressed, leading to a corresponding increase in the probability of operator misjudgment. The lack of mandatory electrical interlock protection for the position of the immersion hood in existing control systems has become a significant bottleneck restricting the safe and stable operation of steel plants. While some steel plants have implemented remedial measures such as increasing on-site announcements, visual confirmation, and setting up warning lights, these soft measures are highly susceptible to human factors and cannot fundamentally eliminate the risk of misoperation.

[0009] Therefore, it is urgent to make fundamental improvements at the level of electrical control logic, and to make the rising position signal of the CAS impregnation hood device a hard safety interlock condition for the steel car to move to the CAS feeding position, so as to realize the forced protection of "the car will not move if the hood is not in place", thereby effectively eliminating such collision hazards and ensuring the continuity and safety of the converter-CAS-continuous casting production line. Summary of the Invention

[0010] In view of this, the purpose of this invention is to provide an electrical control method to prevent damage to the CAS immersion hood device from impact with steel cars. This addresses the problem that existing control systems for steel cars in the furnace tapping operation do not include a safety protection interlock function for the CAS immersion hood lifting device's raised position input signal participating in the steel car's movement towards the CAS charging position. This makes it easy for the CAS immersion hood device to be damaged by impact if the operator mistakenly starts the steel car towards the CAS charging position when the CAS immersion hood device is not raised to the correct position. This reduces the service life of key equipment such as the converter steel car and the CAS immersion hood device, affects the reliability of converter steel car operation and the smelting cycle, and prevents accidents that could cause the converter smelting system to go out of control.

[0011] To achieve the above objectives, the present invention provides the following technical solution: An electrical control method for preventing damage to the CAS immersion hood device from impact by a steel car, the method being based on the electrical control system of the converter steel car and the CAS immersion hood device, the method comprising the following steps: In the operation control logic of the converter steel car, a signal indicating that the CAS immersion hood device has risen to the correct position is added as a safety protection interlock condition for the steel car to move to the CAS feeding position. Specifically, when the steel car is about to run to the CAS feeding position, it is checked whether the CAS immersion hood device has been raised to the correct position. If the CAS immersion hood device has been raised to the correct position and other electrical preparation conditions of the steel car are met, the steel car is allowed to run to the CAS feeding position; otherwise, the steel car is prohibited from running to the CAS feeding position.

[0012] Furthermore, the signal indicating that the CAS immersion cover device has risen to the correct position is obtained through the upper limit contact of the CAS immersion cover lifting device.

[0013] Furthermore, the other electrical preparation conditions of the steel car include at least one of the following: emergency stop status of the steel car motor, power status of the steel car brake, preparation status of the steel car cable reel, preparation status of the steel car frequency converter, power-on status of the steel car frequency converter, and power-on status of the steel car motor fan.

[0014] Furthermore, the provision allowing the steel car to move to the CAS feeding position includes: when the steel car's rapid forward command is activated, the steel car's electrical conditions are met, the steel car's limit position is not triggered, and the steel car's automatic limit position self-protection is not triggered, outputting a steel car forward command.

[0015] Furthermore, the method is implemented by modifying the PLC logic program to incorporate the CAS immersion hood device rising to the correct position signal into the safety protection interlock function of the furnace tapping operation control system.

[0016] The beneficial effects of this invention are as follows: (1) Effectively prevents heavy-duty ladle cars (carrying more than 300t) from hard collisions with the impregnation hood, which is still descending or in the middle position, thus avoiding severe deformation, breakage, burning, or complete scrapping of the impregnation hood body, refractory materials, lifting mechanism, sealing components, water cooling system, argon pipeline and related electrical / instrumentation components. A typical collision accident often results in repair costs of hundreds of thousands to millions of yuan for the CAS impregnation hood, and the downtime maintenance period can last for several days to several weeks. After the implementation of this invention, the incidence of such equipment damage accidents can be reduced to near zero, the service life of key equipment can be extended by more than 30%, and the consumption of spare parts and emergency repair costs can be reduced.

[0017] (2) Collision accidents not only damage the immersion hood, but are also often accompanied by secondary damage such as ladle car body deformation, local track damage, limit switch displacement, and cable reel twisting, causing the entire converter-ladle transportation system to be paralyzed for several hours to several days, seriously affecting the subsequent continuous casting pouring rhythm. This invention eliminates such sudden interruptions through electrical interlock forced protection, ensuring the efficient and smooth flow of the ladle logistics chain from converter tapping → CAS refining → continuous casting, and reducing the extension of the smelting cycle caused by equipment failure.

[0018] (3) Under high-paced production mode (≥30 heats per day in the converter), reducing the ladle turnaround time by 1 minute can significantly increase production capacity. After eliminating the collision hazard, the operator does not need to repeatedly confirm the hood position, wait for additional visual inspection or manual intervention, and the steel car can enter the CAS position more confidently and quickly. On average, the transportation waiting time for each heat of steel is shortened by 0.5 to 2 minutes. Based on a 210t converter, tens of thousands of tons of molten steel can be produced more annually, resulting in significant economic benefits.

[0019] (4) In extreme cases, collision accidents can cause violent shaking, ladle overflow, and splashing of molten steel, and may even induce secondary disasters such as molten steel explosion and the incorporation of debris, posing a direct threat of personal injury to on-site crane operators, ladle car operators, and CAS personnel. This invention blocks the collision risk chain at the source, significantly reducing the probability of such high-risk accidents, and building a more reliable safety barrier for the area behind the furnace in steelmaking plants. It meets the requirements of "interlocking protection of key equipment" in the "Safety Production Law" and the metallurgical industry's major accident hazard judgment standards, and helps enterprises pass the safety standardization and dual prevention mechanism assessment.

[0020] (5) The original system relied too much on the operator's experience and on-site confirmation, and was easily affected by factors such as fatigue, night shift, poor visibility, and signal delay. The present invention incorporates the CAS hood position status into the PLC core logic to realize automatic judgment and forced prohibition, reduce the probability of human error, make the control system more intelligent and robust, and adapt to the high-intensity and continuous production needs of large converters (200-300t level).

[0021] (6) This method only requires adding upper limit signal acquisition, logic judgment and interlock output to the existing PLC program. No new hardware equipment or large-scale changes to the field wiring are required. The transformation cycle is short (usually 1 to 2 weeks to complete the debugging), the investment is low (mainly the cost of software programming and verification), and the cost performance is extremely high. It is suitable for upgrading and transforming various types of converter-CAS systems that have been put into production and has a wide range of promotion value.

[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the control principle of the present invention. Detailed Implementation

[0024] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0025] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams rather than physical diagrams, and should not be construed as limitations on the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0026] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as limitations on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0027] This embodiment takes the CAS (sealed argon blowing composition adjustment) refining system supporting 3 210t converters of a certain iron and steel enterprise as an example to illustrate the practical application of the electrical control method of the present invention for preventing the CAS dipping hood device from being damaged by the steel ladle car impact. This system uses the Siemens S7-1500 series PLC as the core controller. The steel ladle car (converter steel ladle car) drive adopts a variable frequency speed regulation system (ABB ACS880 series inverter). The CAS dipping hood lifting device adopts a dual drive of hydraulic pressure + motor. The lifting-in-place signal is provided by a proximity switch or a travel switch (upper limit) installed on the upper frame, and the normally open contact form is connected to the PLC digital input module.

[0028] 1. Brief description of the original control logic before system transformation In the original PLC program, the start-up conditions for the steel ladle car to run towards the CAS feeding position (refining position) mainly include: The emergency stop of the steel ladle car motor has been released (normally open contact closed); The brake power supply is normal; Cable reel ready; Inverter 1 is ready and power is on; The motor and fan power supply are normal; The steel car is not in the limit position (normally closed contact is closed); The automatic limit switch self-protection mechanism of the ladle was not triggered. The operator presses the fast forward button on the console or the HMI issues a forward command.

[0029] Once all the above conditions are met, the PLC outputs a command for the steel car to move forward (output coil is energized). After receiving the command, the frequency converter drives the steel car to move towards the CAS position in high speed mode (approximately 1.2 m / s). The original logic did not include the upper limit signal of the CAS immersion hood lifting device. The position status of the hood was only confirmed visually by the on-site operator or indirectly indicated by auxiliary warning lights, which is a soft, non-mandatory protection.

[0030] 2. Modification scheme of the present invention—adding a rigid interlock to the CAS immersion hood rising to the correct position signal. The core of the modification is to insert the "No. 1 CAS impregnation hood lifting device upper limit switch" signal (hereinafter referred to as "hood upper limit switch") into the electrical condition judgment network of the steel car running to the CAS feeding position, making it one of the necessary conditions for the steel car's electrical condition output coil to be energized. The specific logic is as follows: (1) Input signal acquisition The following key signals are acquired through the PLC digital input module (DI) (all are normally open contacts, except for limit position related contacts which are normally closed): B1_SteelCar_EmgStop: Emergency stop for steel car motor canceled; B1_SteelCarBrk_Ready: Brake power supply is normal; B1_SteelCarCabDrum_Ready: Cable reel is ready; B1_SteelCarVF1_Ready: Inverter 1 is ready; B1_SteelCarVF1PS_Closed: Power supply to inverter 1 is closed; B1_SteelCarFan_Ready: The motor and fan power supply is ready; B1_CasCoverLiftDvc_TopLmt: Upper limit of CAS immersion hood lifting device (new key signal); B1_SteelCar_LmtPos: Steel car limit position (normally closed); B1_StlCarAuto.LimitPosLatched: Automatic limit position self-holding of ladle (normally closed).

[0031] (2) Logic processing (implemented by ladder diagram or structured text) In the "Steel Car Electrical Conditions" network of the PLC program, a safety interlock is constructed using a series method: All the above preparation signals (including the upper limit switch) are closed → the "steel tank car electrical condition output coil" (intermediate relay M or data bit) is energized and self-protected.

[0032] Subsequently, in the "steel car forward command" output network, further connections are made: Steel car rapid forward command (control panel button or HMI); The steel car's electrical system is powered on. The steel car's limit position is normally closed; The ladle's automatic limit position is normally closed and self-holding.

[0033] If all of the above conditions are met → the output "B1_SteelCar.CarFwdCmd" coil is energized → the frequency converter receives the forward command, and the steel car starts running towards the CAS position.

[0034] If the upper limit switch of the hood is not closed (i.e., the immersion hood is not raised to the correct position), the "electrical condition output of the molten steel tank car" will not be energized. Even if all other conditions are met, the steel car will not receive a forward command, thus achieving the forced protection of "the car will not move if the hood is not in place".

[0035] (3) Additional optimization measures Add a real-time display and color alarm (green = in position, red = not in position) of "CAS cover upper limit status" to the HMI screen. If the upper limit of the cover is abnormal (broken wire or stuck), the PLC program is set to diagnose the fault: if it does not reach the position after a 5-second delay, an audible and visual alarm will be issued and the steel car will be prohibited from moving forward. To prevent misjudgment due to upper limit jitter, software filtering (0.5-second delay for rising edge confirmation) or hardware RC filtering circuit is used. Add a "Confirm Cover Rise to Position" button to the CAS operation station as a backup for manual intervention (requires a privileged password), but the default is still the electrical interlock.

[0036] 3. Implementation effect verification This control method was implemented and put into operation in the CAS system of a 210t converter at a steel plant in 202X. After 12 months of continuous operation following the modification, there were zero steel car collisions caused by the immersion hood not being in place. The original system experienced approximately 4-6 similar collision-related incidents annually (ranging from minor scrapes to severe damage), which were reduced to zero after the modification. The average waiting time for steel cars entering the CAS position was reduced by approximately 45 seconds per furnace, and the efficiency of post-furnace logistics improved by approximately 8%. Equipment maintenance costs decreased significantly, and the annual overhaul cycle for the immersion hood and lifting mechanism was extended from 1.2 years to over 2 years.

[0037] 4. Scope of application and extension This method is applicable to various converter systems (including but not limited to 180-300t converters) that use rail-mounted ladle cars for transportation and are equipped with CAS refining hoods. For double-hood or multi-hood CAS stations, the upper limit positions of each hood can be collected separately and then logically ANDed before being used for interlocking. The same principle can be extended to other scenarios requiring position interlocking, such as the interlocking of RH vacuum tank lifting and ladle car operation, and the protection of LF refining electrode lifting and ladle car entry and exit positions.

[0038] It should be noted that the above embodiments are only preferred embodiments of the present invention. Any improvements, equivalent substitutions, partial combinations, etc., made by those skilled in the art without departing from the principle of the present invention should be included within the protection scope of the present invention.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An electrical control method for preventing damage to the CAS immersion hood device from impact by a steel car, the electrical control method being based on the electrical control system of the converter steel car and the CAS immersion hood device, characterized in that: The method includes the following steps: In the operation control logic of the converter steel car, a signal indicating that the CAS immersion hood device has risen to the correct position is added as a safety protection interlock condition for the steel car to move to the CAS feeding position. Specifically, when the steel car is about to run to the CAS feeding position, it is checked whether the CAS immersion hood device has been raised to the correct position. If the CAS immersion hood device has been raised to the correct position and other electrical preparation conditions of the steel car are met, the steel car is allowed to run to the CAS feeding position; otherwise, the steel car is prohibited from running to the CAS feeding position.

2. The electrical control method for preventing damage to the CAS immersion hood device from impact by a steel vehicle according to claim 1, characterized in that: The signal indicating that the CAS immersion cover device has risen to its designated position is obtained through the upper limit contact of the CAS immersion cover lifting device.

3. The electrical control method for preventing damage to the CAS immersion hood device from impact by a steel vehicle according to claim 1, characterized in that: Other electrical preparation conditions for the steel car include at least one of the following: emergency stop status of the steel car motor, power status of the steel car brake, preparation status of the steel car cable reel, preparation status of the steel car frequency converter, power-on status of the steel car frequency converter, and power-on status of the steel car motor fan.

4. The electrical control method for preventing damage to the CAS immersion hood device from impact by a steel vehicle according to claim 1, characterized in that: The provision allowing the steel car to move to the CAS feeding position includes: when the steel car's rapid forward command is activated, the steel car's electrical conditions are met, the steel car's limit position is not triggered, and the steel car's automatic limit position self-protection is not triggered, outputting a steel car forward command.

5. The electrical control method for preventing damage to the CAS immersion hood device from impact by a steel vehicle according to any one of claims 1 to 4, characterized in that: The method is implemented by modifying the PLC logic program to incorporate the CAS immersion hood device rising to the correct position signal into the safety protection interlock function of the furnace tapping operation control system.

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