A fully automatic vacuum top pouring ingot pouring system and a closed loop control method thereof

Abstract

This invention provides a fully automated vacuum-assisted ingot casting system and its closed-loop control method, relating to the field of ingot casting technology. The casting system includes a vehicle platform, a weighing system, a temperature measurement system, a liquid level monitoring system, and a control system. The vehicle platform is equipped with a traveling mechanism; the sealing protection system includes a liftable vacuum sealing cover, configured to descend during casting to form a sealed chamber that at least accommodates the outlet of the refining ladle and the intermediate ladle, isolating external air before and during casting; the weighing system is mounted on the vehicle platform; the control system is connected to the weighing system, temperature measurement system, and liquid level monitoring system. The coordinated operation of these systems eliminates the need for manual intervention throughout the casting process, achieving fully automated closed-loop control, significantly improving the working environment for operators, reducing labor intensity, and providing reliable technical support for the high-quality and high-efficiency production of large steel ingots.

Description

Technical Field

[0001] This invention relates to the field of steel ingot casting technology, and more specifically, to a fully automatic vacuum-assisted steel ingot casting system and its closed-loop control method. Background Technology

[0002] Large steel ingots are key blanks for large forgings in nuclear power, thermal power, and marine engineering, and their homogeneity and purity directly determine the performance of the final product. Large steel ingots are mostly produced using vacuum casting technology, but existing casting methods have significant shortcomings: After the molten steel flows out of the ladle, it is exposed to the atmosphere and undergoes secondary oxidation, forming oxide inclusions. At the same time, easily oxidized elements such as Al, Ti, and B in the molten steel are severely burned off, causing the composition to deviate from the target value. In addition, the existing casting process relies on overhead cranes for transportation, requiring the use of the overhead crane weighing system for auxiliary judgment. The continuous casting time of the ladle is unstable, the alignment is time-consuming, the liquid level in the tundish cannot be accurately judged, and the repeatability and stability of the operation are poor. Moreover, the high temperature radiation of the molten steel leads to a harsh working environment and high labor intensity. Summary of the Invention

[0003] The purpose of this invention is to provide an integrated and automated casting system that enables oxidation-free casting and precise process control of molten steel from the refining ladle to the ingot mold.

[0004] To address the aforementioned problems, this invention provides a fully automated vacuum ingot casting system and its closed-loop control method.

[0005] In a first aspect, the present invention provides a fully automatic vacuum casting system for steel ingots, including a vehicle platform, a weighing system, a temperature measuring system, a liquid level monitoring system, and a control system.

[0006] The vehicle platform is equipped with a traveling mechanism for moving between pouring stations; The sealing protection system includes a liftable vacuum sealing hood, which is configured to descend during pouring to form a sealed chamber that at least accommodates the outlet of the refining ladle and the intermediate ladle, so as to isolate external air before and during pouring. The weighing system is installed on the vehicle platform to monitor the weight data of the molten steel in the refining ladle in real time; The temperature measurement system is used to measure the temperature data of molten steel in the tundish or in the pouring stream during the pouring process; The liquid level monitoring system is used to monitor the real-time liquid level height data of molten steel in the tundish; and The control system is connected to the weighing system, temperature measurement system, and liquid level monitoring system respectively, and is configured as follows: Based on weight data, temperature data, and liquid level data, and in accordance with the preset pouring control logic, the opening of the flow regulating mechanism set at the outlet of the refining ladle is automatically adjusted to control the flow rate of molten steel flowing into the tundish.

[0007] The beneficial effects of the fully automatic vacuum casting system for steel ingots of the present invention are: The casting system can move flexibly between workstations via a vehicle platform and its traveling mechanism, eliminating the need for overhead cranes. This significantly improves operational efficiency and positioning accuracy, while reducing overhead crane usage and manual labor intensity. The sealing protection system uses a liftable vacuum seal to create a sealed chamber before and during casting, effectively isolating the refining ladle and tundish from external air. This fundamentally eliminates the possibility of molten steel coming into contact with air, preventing secondary oxidation and alloy element loss, and greatly improving the purity and compositional stability of the steel ingot. The weighing, temperature measurement, and liquid level monitoring systems collect real-time data on three key process parameters: the weight of molten steel in the refining ladle, the temperature of molten steel in the tundish, and the liquid level in the tundish. This provides a comprehensive and accurate data foundation for the control system. Based on this multi-source real-time data, the control system automatically adjusts the opening of the flow regulating mechanism at the refining ladle outlet according to the preset casting control logic, achieving precise and dynamic control of the molten steel flow rate, thereby ensuring the stability and repeatability of the casting process. The coordinated operation of the above systems enables the entire casting process to be completed without human intervention, achieving fully automated closed-loop control, significantly improving the working environment of operators, reducing labor intensity, and providing reliable technical support for the high-quality and high-efficiency production of large steel ingots.

[0008] Optionally, the sealing protection system also includes a vacuum pump unit and an inert gas storage tank, which are respectively connected to the sealed chamber through pipelines; the control system is also configured to selectively control the vacuum pump unit to evacuate the sealed chamber before casting, or to control the inert gas storage tank to fill the sealed chamber with inert gas to replace the air inside.

[0009] Optionally, the sealed chamber is formed by a vacuum sealing cover that, after being lowered, tightly engages with the upper part of a vacuum cover disposed on the steel ingot mold.

[0010] Optionally, the weighing system includes multiple weighing sensors, which are integrated between the vehicle platform and the traveling mechanism, or located below the trunnion support of the refining ladle, for real-time weighing of the total weight of the refining ladle and the molten steel inside.

[0011] Optionally, the temperature measurement system includes a multi-degree-of-freedom robotic arm fixed to the vehicle platform and a temperature measuring element driven by it. The robotic arm responds to the instructions of the control system and drives the temperature measuring element to automatically insert into a predetermined temperature measuring point in the intermediate package.

[0012] Optionally, the liquid level monitoring system includes a non-contact radar liquid level sensor or a laser liquid level sensor, which is installed inside the vacuum sealing cover and the detection end faces the molten steel surface inside the tundish.

[0013] Optionally, the preset pouring control logic includes a closed-loop main control loop based on the level-time curve; the control system is further configured to: compare the real-time level height data fed back by the level monitoring system with the target value of the level-time curve, and calculate the target opening adjustment amount required by the flow regulating mechanism in real time based on the deviation value.

[0014] Optionally, the preset casting control logic also includes a closed-loop sub-control loop based on the weight-time curve; the control system is further configured as follows: The instantaneous pouring flow rate of molten steel is calculated based on the real-time weight data fed back by the weighing system; The instantaneous pouring flow rate is compared with a preset safe flow rate threshold; and When the instantaneous injection flow rate is lower than the safe flow rate threshold, it is determined to be a precursor to water blockage and an early warning signal is issued.

[0015] Optionally, it also includes an argon control system connected to the bottom-blowing argon interface of the refining ladle; the control system is also connected to the argon control system and further configured to: dynamically adjust the argon supply parameters of the argon control system according to the comparison results of the real-time temperature data fed back by the temperature measurement system and the preset target temperature range, so as to adjust the rate of temperature drop of the molten steel in the refining ladle.

[0016] Secondly, the present invention provides a closed-loop control method for a fully automated vacuum ingot casting system, comprising the following steps: S1. Move the gating system to the gating station via the vehicle platform and control the vacuum sealing cover to descend, forming a sealed chamber; S2. Evacuate the sealed chamber or fill it with inert gas to replace the atmosphere in the sealed chamber with a protective atmosphere. S3. Activate the flow regulation mechanism to start pouring into the tundish and ingot mold, and start real-time data acquisition, including at least: the weight data of the refining ladle monitored by the weighing system, the temperature data of the molten steel measured by the temperature measurement system, and the liquid level height data in the tundish measured by the liquid level monitoring system. S4. The control system dynamically adjusts the opening of the flow regulating mechanism according to the collected liquid level height data and the preset liquid level-time closed-loop control curve to control the liquid level in the intermediate tank to rise at a uniform speed according to the target speed. The control system also calculates the instantaneous pouring flow rate according to the collected weight data and compares it with the preset safe flow rate threshold. When the instantaneous pouring flow rate is lower than the safe flow rate threshold, it determines that there is a risk of water blockage and issues a warning signal. S5. When the pouring reaches the preset termination condition, the flow control mechanism is closed to stop the pouring, and after maintaining the process under a protective atmosphere for a preset time, the vacuum sealing cover is raised. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the fully automatic vacuum casting system for steel ingots in an embodiment of the present invention; Figure 2 This is a flowchart of the closed-loop control method in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Vehicle platform; 2. Walking mechanism; 3. Refining ladle; 4. Outlet; 5. Vacuum cover; 6. Vacuum sealing cover; 7. Interface; 8. Intermediate ladle; 9. Ingot mold; 10. Weighing system; 11. Temperature measurement system; 12. Liquid level monitoring system; 13. Control system; 14. Argon gas control system. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0021] It should be noted that the terms "one" and "more" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] Example 1 Please refer to Figure 1This embodiment provides a fully automatic vacuum casting system for steel ingots, including a vehicle platform 1, a sealing protection system, a weighing system 10, a temperature measuring system 11, a liquid level monitoring system 12, and a control system 13.

[0023] The vehicle platform 1 is a frame-type steel structure platform with a traveling mechanism 2 at its bottom. The traveling mechanism 2 uses a rail-type wheel set, which is driven by a drive motor and a reducer, moving the vehicle platform 1 along the track laid on the ground of the pouring span between the various pouring positions. The upper surface of the vehicle platform 1 is provided with a ladle holder for supporting the refining ladle 3. The ladle holder has a positioning structure that matches the bottom shape of the refining ladle 3 to ensure accurate positioning after the refining ladle 3 is hoisted onto the vehicle platform 1.

[0024] The sealing protection system includes a vacuum sealing cover 6, a lifting mechanism for the sealing cover, and a sealing ring. The vacuum sealing cover 6 is a bell-shaped shell structure with an open lower end, and its internal volume is larger than the combined external dimensions of the refining ladle 3 and the tundish 8. The vacuum sealing cover 6 is connected to the vehicle platform 1 via a lifting mechanism driven by a hydraulic cylinder or electric push rod, enabling the vacuum sealing cover 6 to move vertically up and down. During the pouring operation, the vacuum sealing cover 6 descends under the drive of the lifting mechanism, and its lower edge fits tightly against the base platform surrounding the tundish 8 or the upper surface of the vacuum cover 5 above the tundish 8, forming a sealed chamber inside the vacuum sealing cover 6. The outlet 4 of the refining ladle 3 and the tundish 8 are completely contained within this sealed chamber. The sealing ring is located between the lower edge of the vacuum sealing cover 6 and the mating surface to ensure the sealing performance of the sealed chamber. The sealing protection system pre-establishes the sealed chamber before pouring and maintains a sealed state throughout the pouring process, thereby effectively isolating the internal space of the sealed chamber from the external atmospheric environment.

[0025] The weighing system 10 is mounted on the vehicle platform 1 and is used to monitor the weight data of the molten steel in the refining ladle 3 in real time. The weighing system 10 uses multiple weighing sensors, which are column-type or spoke-type resistance strain sensors with high-temperature compensation function, enabling them to maintain measurement accuracy under the thermal radiation environment of the molten steel. The weighing sensors are installed between the vehicle platform 1 and the ladle holder. The entire weight of the refining ladle 3 is transferred to the weighing sensors through the ladle holder, and the weighing sensors convert it into an electrical signal output.

[0026] The temperature measurement system 11 is used to measure the temperature data of the molten steel in the tundish 8 during the pouring process. The temperature measurement system 11 includes a temperature measuring element and a signal conditioning module. The temperature measuring element adopts a consumable thermocouple or a continuous temperature measuring probe, which is inserted into the tundish 8 at a certain depth below the surface of the molten steel at a preset cycle during the pouring process to measure the temperature. The measured temperature signal is amplified and filtered by the signal conditioning module and then transmitted to the control system 13.

[0027] The liquid level monitoring system 12 is used to monitor the real-time liquid level of molten steel in the tundish 8. The liquid level monitoring system 12 employs a combination of a high-temperature resistant industrial camera and an image processing unit. The high-temperature resistant industrial camera is installed on the top inner wall of the vacuum sealing cover 6, with its lens passing through a viewing window on the sealing cover and facing the molten steel surface in the tundish 8. A purging device is installed at the front end of the lens to prevent moisture and dust adhesion. The camera continuously acquires images of the molten steel surface in the tundish 8. The image processing unit performs grayscale analysis and edge recognition on the acquired images, extracts the position coordinates of the molten steel surface, and calculates the actual height of the liquid level in the tundish 8 by combining the camera's installation height and calibration parameters.

[0028] The control system 13 is connected to the weighing system 10, the temperature measuring system 11, and the liquid level monitoring system 12. The control system 13 uses an industrial programmable logic controller (PLC) or an embedded industrial computer as its core processor, integrating a data acquisition module, a calculation module, and an execution instruction output module. The control system 13 is configured to receive the weight data of molten steel in the refining ladle 3 transmitted by the weighing system 10, the temperature data of molten steel in the tundish 8 transmitted by the temperature measuring system 11, and the liquid level height data in the tundish 8 transmitted by the liquid level monitoring system 12. It then performs calculations according to the pre-set pouring control logic within the control system 13 and automatically outputs an opening control command to the flow regulating mechanism located at the bottom outlet 4 of the refining ladle 3 based on the calculation results. The flow regulating mechanism is a sliding gate mechanism, including an upper gate, a lower gate, and a horizontally sliding slide plate. The control system 13 outputs an electrical signal to the slide plate drive mechanism, which moves the slide plate to change the effective flow cross-sectional area of ​​the gate, thereby controlling the flow rate of molten steel flowing from the refining ladle 3 into the tundish 8.

[0029] In this embodiment, the vehicle platform 1 and its traveling mechanism 2 enable flexible relocation and alignment of the system, significantly improving operational efficiency. The sealing protection system isolates the refining ladle 3 and tundish 8 from external air throughout the entire casting cycle, preventing secondary oxidation of molten steel and loss of alloying elements from the source, thus ensuring the purity of the steel ingot. The three sensor systems for weighing, temperature measurement, and liquid level monitoring comprehensively collect key data of the casting process from three dimensions: mass, temperature, and liquid level, providing sufficient real-time information support for the accurate decision-making of the control system 13. The control system 13 performs closed-loop calculations based on multi-source data fusion and automatically adjusts the opening of the flow regulation mechanism, achieving precise automatic control of the casting speed. The entire process requires no manual intervention, ensuring the stability and repeatability of the casting process. The various systems work together to achieve fully automated vacuum-protected casting of steel ingots.

[0030] Example 2 Based on Embodiment 1, the sealing protection system of this embodiment further includes a vacuum pump unit and an inert gas storage tank. The vacuum pump unit is a two-stage pumping unit composed of a Roots vacuum pump and a rotary vane vacuum pump, characterized by high pumping speed and high ultimate vacuum. The vacuum pump unit is connected to the sealed chamber through a pumping pipeline, which is equipped with a vacuum valve and a vacuum pressure gauge. The inert gas storage tank is a high-pressure tank filled with high-purity argon gas. The inert gas storage tank is connected to the sealed chamber through a gas supply pipeline, which is equipped with a pressure regulating valve and a mass flow controller.

[0031] The vacuum pump unit's extraction pipeline and the inert gas storage tank's supply pipeline are connected to interface 7 of the sealed chamber via a T-joint. An electrical interlock is installed between the vacuum valve and the supply valve to prevent simultaneous opening and subsequent suction of inert gas by the vacuum pump. A vacuum pressure gauge is installed on the side wall of the sealed chamber to monitor the pressure value inside the chamber in real time and transmit the pressure signal to the control system 13.

[0032] The control system 13 is also configured to: before pouring, selectively control the vacuum pump group to evacuate the sealed chamber according to a preset protection mode selection signal, or control the inert gas storage tank to fill the sealed chamber with inert gas to replace the air inside. When the vacuum mode is selected, the control system 13 closes the valve on the gas supply line, opens the vacuum valve, and starts the vacuum pump group to pump the pressure in the sealed chamber to the preset vacuum level. When the inert gas protection mode is selected, the control system 13 closes the vacuum valve, opens the valve on the gas supply line, fills the sealed chamber with argon gas, and simultaneously opens the exhaust valve on the sealed chamber to continuously purge the residual air in the chamber with argon gas until the oxygen content detector in the chamber shows that the oxygen concentration has dropped below the preset value.

[0033] In this embodiment, the vacuum pump unit can quickly evacuate the sealed chamber to a high vacuum state, which is suitable for casting special steel grades that are highly sensitive to oxygen and nitrogen; the inert gas storage tank can fill the sealed chamber with argon gas to form a positive pressure inert atmosphere, which not only isolates the air but also avoids the loss of elements due to volatilization that may occur in molten steel under vacuum; the control system 13 can selectively switch between two protection modes according to process requirements, so that the system can flexibly adapt to the casting protection requirements of different steel grades and different working conditions, making it more applicable and more versatile.

[0034] Example 3 Based on Embodiment 1, this embodiment further defines the sealing structure of the sealed chamber. A vacuum cover 5 is fixedly installed above the steel ingot mold 9. The vacuum cover 5 is an annular cover plate structure with a through hole in its center for molten steel to pass through. The outer edge dimension of the vacuum cover 5 is larger than the inner edge dimension of the lower opening of the vacuum sealing cover 6. A sealing groove is formed around the upper part of the vacuum cover 5 in a circumferential direction. The cross-sectional shape of the sealing groove is rectangular or trapezoidal. A high-temperature resistant sealing strip is embedded in the sealing groove. The sealing strip is made of ceramic fiber braided rope or flexible graphite tape.

[0035] After the vacuum sealing cover 6 descends, its lower edge aligns with the sealing groove on the upper part of the vacuum cover 5 and is tightly embedded therein. Through the weight of the sealing cover itself or the continuous downward pressure of the lifting mechanism, the lower end face of the sealing cover forms a tight sealing fit with the sealing strip in the sealing groove. The vacuum sealing cover 6, the vacuum cover 5, and the sealing joint surface between them together form a sealed chamber. The intermediate ladle 8 and the refining ladle 3 below the vacuum cover 5 are both located inside the sealed chamber.

[0036] When the vacuum sealing cover 6 rises, its lower edge disengages from the sealing groove, and the seal is released. The sealing groove also serves as a guide and positioning feature, ensuring that the vacuum sealing cover 6 accurately returns to the same sealing position each time it descends.

[0037] In this embodiment, the vacuum cover 5 is fixed above the tundish 8 and arranged together with the tundish 8 at the casting station. The vacuum sealing cover 6 only needs to move up and down in the vertical direction to complete the precise sealing fit through the sealing groove. There is no need for complicated horizontal alignment, which simplifies the equipment structure and control logic, reduces the processing accuracy requirements of the sealing mating surface, and the high-temperature resistant sealing strip embedded in the sealing groove can withstand the high temperature heat radiation during the steel pouring process, ensuring the long-term reliability and reusability of the seal under high temperature conditions.

[0038] Example 4 Based on Embodiment 1, this embodiment further defines the specific structure of the weighing system 10. The weighing system 10 includes multiple weighing sensors. In this embodiment, four weighing sensors are preferably used, which are symmetrically arranged in the four corner areas of the vehicle platform 1 along the longitudinal and transverse directions.

[0039] The load cells are integrated between the vehicle platform 1 and the traveling mechanism 2. Specifically, the traveling mechanism 2 consists of multiple wheel sets located on both sides of the vehicle platform 1. A load cell is installed between the top of each wheel set and the lower surface of the vehicle platform 1. The wheel sets are suspended below the vehicle platform 1 via the load cells. The entire weight of the vehicle platform 1, along with the refining ladle 3 and intermediate ladle 8 it carries, is transferred to the wheel sets through the four load cells. The load cells are cylindrical compression-type resistance strain sensors, each with an integrated temperature compensation resistor to eliminate the influence of high-temperature environments on measurement accuracy.

[0040] Optionally, the load cell can be installed below the trunnion support of the refining ladle 3. Trunnions are symmetrically arranged on both sides of the refining ladle 3, and corresponding trunnion supports are provided on the vehicle platform 1. The trunnions rest on the arc-shaped support surface of the trunnion supports. The load cell is located between the bottom of the trunnion support and the vehicle platform 1. The weight of the refining ladle 3 is transmitted to the load cell through the trunnion supports. In practical applications, depending on the equipment's spatial layout and force distribution requirements, a load cell can be installed either between the vehicle platform 1 and the traveling mechanism 2, or below the trunnion support of the refining ladle 3, or both locations can be simultaneously installed.

[0041] The output signals of the four weighing sensors are aggregated through a junction box and transmitted to the control system 13. The control system 13 sums the signals from each sensor to obtain the real-time total weight of the refining ladle 3 and the molten steel inside. The weight of the empty ladle 3 is obtained by tare after calibration. The net weight of the remaining molten steel in the refining ladle 3 is the real-time total weight minus the empty ladle weight.

[0042] In this embodiment, a weighing sensor is integrated between the vehicle platform 1 and the traveling mechanism 2. The weighing object covers the entire load on the vehicle platform 1, enabling the acquisition of total weight information including the refining ladle 3 and the intermediate ladle 8. Furthermore, the sensor is located below the vehicle platform 1, facilitating inspection and maintenance. Alternatively, a weighing sensor positioned below the trunnion support of the refining ladle 3 can weigh only the refining ladle 3 and its molten steel, providing more direct data with fewer interference sources. These two installation positions can be flexibly selected or combined according to actual needs. Simultaneously, by evenly distributing multiple sensors circumferentially and summing their signals, measurement errors caused by the refining ladle 3's center of gravity shift or the vehicle's tilt are effectively offset, ensuring the accuracy and reliability of the weighing data.

[0043] Example 5 Based on Embodiment 1, this embodiment further defines the specific structure of the temperature measurement system 11. The temperature measurement system 11 includes a multi-degree-of-freedom robotic arm fixed on the vehicle platform 1 and a temperature measuring element driven by the robotic arm.

[0044] The robotic arm is a six-axis articulated industrial robot. Its base is fixedly mounted on the rear or side of the upper surface of the vehicle platform 1. Each joint of the robotic arm is driven by a servo motor, enabling multi-degree-of-freedom spatial movement under the command of the control system 13. A temperature sensing element clamping device is installed on the end effector of the robotic arm to hold the temperature sensing element. The temperature sensing element is a consumable thermocouple, consisting of a paper tube, thermocouple wire, and quartz tube. It is a single-use element, automatically discarded and replaced with a new thermocouple after each temperature measurement to ensure the response speed and accuracy of each measurement. Alternatively, a continuous temperature probe can be used, i.e., a long-life temperature sensing element composed of a corundum protective tube and internal thermocouple wire, which can be reused in multiple temperature measurement cycles.

[0045] Responding to the instructions of the control system 13, the robotic arm moves the temperature measuring element held at its end to above the tundish 8 according to a preset temperature measurement cycle. Then, it descends vertically so that the measuring end of the temperature measuring element is inserted into the molten steel in the tundish 8 at a predetermined depth below the surface. The temperature measuring element remains at the predetermined depth for a preset time to ensure a stable temperature signal. The robotic arm then removes the temperature measuring element from the molten steel and returns to the standby position.

[0046] Within the stroke range of the multi-degree-of-freedom robotic arm, the control system 13 can dynamically adjust the movement trajectory of the robotic arm and the insertion depth of the temperature measuring element according to the placement position of the intermediate drum 8 and the real-time changes in the liquid level, so as to ensure that the temperature measuring end always accurately reaches the predetermined temperature measuring point.

[0047] In this embodiment, the multi-degree-of-freedom robotic arm can simulate manual temperature measurement actions, automatically completing a series of temperature measurement operations such as picking up parts, moving, inserting, pausing, withdrawing, and returning to the original position. This replaces the traditional manual method of inserting thermocouples into molten steel, keeping operators away from high-temperature radiation areas and significantly reducing labor intensity and safety risks. At the same time, the robotic arm's movements are precise and the timing is controllable, ensuring that the insertion position and dwell time remain consistent for each temperature measurement. This eliminates the inconsistencies of manual operations, improves the accuracy and comparability of temperature measurement data, and provides a reliable data source for temperature compensation control.

[0048] Example 6 Based on Embodiment 1, this embodiment further defines the specific structure of the liquid level monitoring system 12. The liquid level monitoring system 12 includes a non-contact radar liquid level sensor or a laser liquid level sensor.

[0049] The radar level sensor employs the principle of frequency-modulated continuous wave radar or pulse radar. Its transmitting antenna emits microwave signals towards the molten steel surface. These microwave signals are reflected upon encountering the molten steel surface, and the receiving antenna receives the reflected signals. The internal signal processing unit calculates the distance from the antenna end face to the liquid surface based on the frequency or time difference between the transmitted and received signals. Combined with the known antenna installation height, it then calculates the absolute height of the molten steel surface. The radar level sensor has the ability to penetrate flue gas and dust, and can still operate stably even in the presence of small amounts of water vapor and fine dust within the vacuum-sealed enclosure 6.

[0050] Laser level sensors employ phase-based or pulsed laser ranging principles. The laser emitter projects a laser beam towards the molten steel surface. After reflection from the surface, the beam is captured by a receiver. The sensor calculates the distance to the liquid surface based on the laser's time of flight or phase difference. Laser level sensors offer high measurement accuracy and fast response.

[0051] The radar level sensor or laser level sensor is installed on the upper part of the inner side of the vacuum sealing cover 6, specifically on the inner wall of the vacuum sealing cover 6. The sensor is fixed by a mounting flange on the sealing cover, and its detection end passes through the center hole of the mounting flange and faces the molten steel level inside the tundish 8. A sealing gasket is provided between the mounting flange and the wall of the sealing cover to prevent gas in the sealed chamber from leaking through the installation gap. The sensor's signal cable is led out to the external control system 13 through an aviation connector on the wall of the sealing cover.

[0052] The liquid level sensor starts working before the pouring begins, continuously collecting liquid level data in the intermediate ladle 8 at a sampling period of milliseconds throughout the pouring process, and uploading the data to the control system 13 in real time.

[0053] In this embodiment, a radar level sensor or a laser level sensor continuously measures the molten steel level in the tundish 8 from above in a non-contact manner. The sensor is installed on the inner wall of the vacuum sealing cover 6 with its detection end facing the liquid surface. The sensor itself does not contact the molten steel, avoiding high-temperature ablation and molten steel adhesion, resulting in a long service life and low maintenance costs. The non-contact measurement method does not interfere with the molten steel flow field, does not introduce new inclusions, and has no impact on the purity of the molten steel. Furthermore, both sensors have millisecond-level response speeds, enabling them to track rapid changes in the liquid level in real time. This provides high-frequency, high-precision liquid level feedback signals for the real-time closed-loop regulation of the control system 13, which is crucial data support for achieving constant-speed casting.

[0054] Example 7 Based on Embodiment 1, this embodiment further defines the preset pouring control logic in the control system 13. The preset pouring control logic includes a closed-loop main control loop based on the liquid level-time curve.

[0055] The control system 13 has a pre-stored ideal pouring curve that matches the steel grade and ingot specifications. This curve is a target curve showing the change of liquid level height over time. The vertical axis represents the target height of the molten steel in the tundish 8, and the horizontal axis represents the pouring time. At different stages of pouring, such as the initial pouring, the main pouring, and the final pouring, the liquid level-time curve has different slopes, corresponding to different optimal liquid level rise rates.

[0056] The control system 13 is further configured to perform the following closed-loop control operation: In each control cycle, the control system 13 reads the real-time liquid level height data of the molten steel in the tundish 8 fed back by the liquid level monitoring system 12, compares the real-time liquid level height value with the target liquid level height value corresponding to the current time point on the liquid level-time curve, and calculates the deviation value between the two, including the magnitude and direction of the deviation value. Based on the deviation value, the control system 13, combined with a preset proportional-integral-derivative control algorithm, calculates the target opening adjustment amount required by the flow regulating mechanism in real time. Specifically, a larger deviation value corresponds to a larger opening adjustment amount to quickly correct the liquid level deviation, and a smaller deviation value corresponds to a smaller opening adjustment amount to avoid overshoot. The control operation result is output to the drive device of the flow regulating mechanism in the form of an electrical signal, and the drive device then adjusts the slide plate position to change the nozzle opening.

[0057] In this embodiment, the closed-loop main control loop based on the liquid level-time curve takes the precise control of the molten steel level in the tundish 8 as the core control of casting quality. Through high-speed closed-loop feedback of real-time detection, real-time comparison, real-time calculation, and real-time execution, the actual liquid level is always kept close to the target curve, so that the molten steel level in the tundish 8 rises at a set optimal speed. This effectively avoids liquid level fluctuations caused by the lag of human judgment and experience differences, ensures the stability and uniformity of the filling of molten steel in the ingot mold 9, significantly reduces the risk of slag entrapment and gas entrapment on the liquid surface, and improves the internal density and surface quality of the ingot.

[0058] Example 8 Based on Embodiment 7, this embodiment further supplements and defines the preset pouring control logic. The preset pouring control logic also includes a closed-loop sub-control loop based on the weight-time curve.

[0059] In addition to executing the liquid level-time main closed-loop control, control system 13 also synchronously executes the following secondary loop control logic: First, the control system 13 calculates the instantaneous pouring flow rate of molten steel based on the weight data of the refining ladle 3 fed back in real time by the weighing system 10, as follows: The weight data is differentiated over time, that is, the weight difference between two adjacent sampling times is divided by the sampling time interval to obtain the average flow rate within that time period, which is then used as the instantaneous pouring flow rate at the current moment. Since the weight data decreases monotonically with time, the differentiation result is negative; its absolute value is the numerical value of the instantaneous pouring flow rate.

[0060] Secondly, the control system 13 compares the instantaneous pouring flow rate with a safe flow rate threshold pre-stored in the control system 13. The safe flow rate threshold is a preset minimum allowable flow rate value, which is set comprehensively based on the diameter of the ladle 3 outlet, the temperature of the molten steel, the characteristics of the steel grade, and the process requirements, and represents the minimum molten steel flow rate required to maintain normal pouring.

[0061] When the control system 13 determines that the instantaneous pouring flow rate is lower than the safe flow rate threshold, it means that the flow rate of molten steel flowing from the refining ladle 3 into the tundish 8 has abnormally decreased. At this time, the control system 13 immediately determines that this is a precursor to blockage and issues a warning signal. The warning signal includes an audible alarm, a visual alarm, and a warning message displayed on the human-machine interface of the operator station. At the same time, the control system 13 treats this prediction information as an instruction with higher priority than conventional liquid level control, and prioritizes the execution of emergency intervention measures.

[0062] In this embodiment, the weight-time closed-loop secondary control loop and the level-time primary control loop constitute a dual-closed-loop collaborative system. The secondary loop obtains instantaneous pouring flow information in real time by differentiating the weight data of the refining ladle 3 over time. It can keenly detect abnormal flow attenuation caused by nozzle blockage, slide blockage, etc., and issue an early warning before the nozzle blockage accident completely occurs, thus gaining valuable intervention time for operators and effectively avoiding pouring interruption and steel ingot scrapping caused by nozzle blockage. At the same time, the operation of this secondary loop does not rely on additional hardware and can be completed based solely on existing weighing data. It is low-cost, simple to implement, and provides an important safety guarantee function for the system.

[0063] Example 9 Based on Embodiment 1, this embodiment also includes an argon gas control system 14. The argon gas control system 14 is connected to the bottom-blowing argon gas interface of the refining ladle 3 via a pipeline. The bottom of the refining ladle 3 is typically equipped with a permeable brick or an argon blowing port for blowing argon gas into the molten steel to achieve steel agitation and temperature homogenization. The argon gas control system 14 includes an argon gas source, a pressure reducing valve, a flow regulating valve, a mass flow meter, and a switching valve. These components are connected sequentially via pipelines. The flow regulating valve and the mass flow meter form a closed-loop flow regulation circuit, capable of accurately outputting the set argon gas flow rate according to the instructions of the control system 13.

[0064] The control system 13 is signal-connected to the argon gas control system 14. Specifically, the analog output module of the control system 13 is electrically connected to the flow regulating valve of the argon gas control system 14, and the analog input module of the control system 13 is electrically connected to the mass flow meter.

[0065] The control system 13 is further configured to execute temperature compensation control logic: during the pouring process, the control system 13 compares the real-time temperature data of the molten steel in the tundish 8 fed back by the temperature measuring system 11 with the preset target temperature range. The target temperature range is the interval between the lowest and highest temperatures allowed by the pouring temperature process specification for this steel grade.

[0066] If the real-time temperature data is lower than the preset target lower limit, it indicates that the molten steel temperature is too low and there is a risk of solidification. At this time, the control system 13 increases the argon supply of the argon control system 14, that is, increases the opening of the flow regulating valve, and introduces a larger flow of argon into the refining ladle 3 to enhance the stirring of the molten steel, promote the homogenization of the molten steel temperature in the ladle, and slow down the rate of temperature drop of the molten steel during transportation and pouring. If the real-time temperature data is higher than the preset target upper limit, it indicates that the molten steel temperature is too high. At this time, the control system 13 reduces or stops the argon supply of the argon control system 14 to avoid excessive stirring, which would aggravate the scouring of the ladle lining by the molten steel and the temperature rise.

[0067] The adjustment range of argon flow rate is positively correlated with the degree of deviation of the measured temperature from the target value: the greater the deviation, the greater the adjustment range.

[0068] In this embodiment, the argon gas control system 14 dynamically adjusts the bottom-blowing argon gas supply parameters based on the real-time steel temperature data fed back by the temperature measurement system 11, thereby achieving active adjustment of the rate of temperature drop of the molten steel in the refining ladle 3. This ensures that the pouring temperature is always maintained within the process window range, avoiding quality problems such as nozzle freezing due to excessively low steel temperature or coarse as-cast microstructure due to excessively high temperature. At the same time, this temperature compensation control works in conjunction with the liquid level closed-loop control and the weight secondary loop early warning to form a full-parameter closed-loop control system covering the three dimensions of flow rate, liquid level, and temperature. This is an important technical guarantee for the fully automatic and precise pouring of this invention.

[0069] Example 10 Please combine Figure 2 This embodiment provides a closed-loop control method for the fully automatic vacuum casting system for steel ingots described in any one of the preceding embodiments one to nine, including the following steps S1 to S5.

[0070] Step S1: Move the casting system to the casting station via the vehicle platform 1, and control the vacuum sealing cover 6 to descend to form a sealed chamber. Specifically, the control system 13 sends a travel command to the drive motor of the traveling mechanism 2. The vehicle platform 1 travels along the track to the target casting station and stops, and the position is confirmed by the position detection sensor. The control system 13 then sends a descent command to the sealing cover lifting mechanism. The vacuum sealing cover 6 descends at a constant speed under the drive of the lifting mechanism, and its lower edge fits tightly with the sealing groove on the upper part of the vacuum cover 5, forming a sealed chamber that completely accommodates the refining ladle 3 and the intermediate ladle 8. The control system 13 confirms that the sealing is complete by the sealing position detection switch or pressure sensor.

[0071] Step S2: Evacuate the sealed chamber or fill it with inert gas to replace the atmosphere in the sealed chamber with a protective atmosphere. Specifically, the control system 13 selects either vacuum mode or inert gas mode according to the process settings. If vacuum mode is selected, the control system 13 opens the vacuum valve and starts the vacuum pump group to pump the pressure in the sealed chamber to the preset vacuum value. The vacuum pressure gauge provides real-time feedback of the pressure value. After reaching the set value, the vacuum pump group switches to a maintenance state. If inert gas mode is selected, the control system 13 opens the gas supply line valve to fill the sealed chamber with high-purity argon gas, while simultaneously opening the exhaust valve to discharge the mixed gas until the oxygen content detector in the chamber shows that the oxygen concentration has dropped below the preset safety value. Then, the argon gas flow rate is reduced to maintain a slightly positive pressure protective atmosphere.

[0072] Step S3: Activate the flow regulation mechanism to begin pouring steel into the tundish 8 and ingot mold 9, and initiate real-time data acquisition. The control system 13 outputs an opening command to the drive mechanism of the sliding gate at the bottom of the refining ladle 3. The sliding plate moves, gradually opening the gate. Molten steel flows from the refining ladle 3 through the outlet into the tundish 8, and then into the ingot mold 9 through the bottom pouring port of the tundish 8. Simultaneously with activating the flow regulation mechanism, the control system 13 initiates the data acquisition program, starting to collect at least the following three types of data in real time: the weight data of the refining ladle 3 monitored by the weighing system 10, the temperature data of the molten steel in the tundish 8 measured by the temperature measuring system 11, and the liquid level height data in the tundish 8 measured by the liquid level monitoring system 12. The above three types of data are continuously collected and transmitted to the control system 13 at a fixed sampling period.

[0073] Step S4: Based on the collected liquid level height data, the control system 13 dynamically adjusts the opening of the flow regulation mechanism according to the preset liquid level-time closed-loop control curve to control the liquid level in the tundish 8 to rise at a uniform speed according to the target rate. Specifically, the control system 13 compares the real-time steel liquid level height in the tundish 8 fed back by the liquid level monitoring system 12 with the target liquid level value at the current time point on the internally stored liquid level-time target curve, calculates the deviation value, and obtains the target position command of the sliding nozzle slide plate after calculation by the proportional-integral-derivative control algorithm. The drive mechanism executes the command to adjust the nozzle opening. The liquid level feedback is collected again in the next control cycle and the above calculation is repeated to form a high-speed closed-loop feedback control.

[0074] Simultaneously, the control system 13 calculates the instantaneous pouring flow rate based on the collected weight data and compares it with a preset safe flow rate threshold. The instantaneous pouring flow rate is calculated by differentiating the weight data over time. When the control system 13 determines that the instantaneous pouring flow rate is lower than the safe flow rate threshold, it identifies a risk of blockage at the water outlet and issues a warning signal, which is displayed as an audible and visual alarm to alert on-site personnel.

[0075] Step S5: When the pouring reaches the preset termination condition, the flow regulation mechanism is closed to stop the pouring. After maintaining the process under a protective atmosphere for a preset time, the vacuum sealing cover 6 is raised. The preset termination condition includes any of the following: the weight of the molten steel in the refining ladle 3 monitored by the weighing system 10 decreases to a preset remaining amount threshold; the liquid level in the tundish 8 monitored by the liquid level monitoring system 12 reaches a preset termination liquid level height; or the preset upper limit of the total pouring time is reached. After the control system 13 detects that the termination condition is met, it sends a closing command to the sliding nozzle drive mechanism, the nozzle is completely closed, and the molten steel stops flowing out. After the pouring stops, the vacuum sealing cover 6 continues to remain sealed, and a vacuum or inert gas protective atmosphere is maintained in the chamber, allowing the molten steel poured into the ingot mold 9 to stand and solidify under the protective atmosphere for a preset time, which facilitates the upward floating and discharge of gas inside the ingot and top shrinkage compensation. After the preset time is reached, the control system 13 controls the lifting mechanism to raise the vacuum sealing cover 6 to the initial position, the sealed chamber opens, the pouring car moves out of the work position, and one pouring operation is completed.

[0076] The closed-loop control method provided in this embodiment, through the complete process of steps S1 to S5, organically connects the establishment of the seal and atmosphere protection before casting, the real-time multi-parameter acquisition and closed-loop control during casting, and the protective static setting and seal release after casting, realizing the fully automated operation from the placement of refining ladle 3 to the completion of casting. Step S4, through the liquid level-time closed-loop main loop, ensures the core quality of the casting process, while the weight-time secondary loop provides redundant safety warning protection. The main and secondary loops work together to ensure that the casting speed accurately tracks the target curve and has the ability to detect early warning signs of accidents. The step of maintaining a preset time under a protective atmosphere after casting stops effectively prevents secondary oxidation and shrinkage defects caused by contact with air at the top of the ingot during solidification, further ensuring the quality of the ingot head. The entire method does not rely on manual judgment or intervention, has a high degree of process standardization and strong repeatability, and provides a reliable technical solution for the large-scale production of large, high-quality steel ingots.

[0077] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A fully automatic vacuum casting system for steel ingots, characterized in that, include: The vehicle platform (1) is equipped with a traveling mechanism (2) for moving between casting stations; A sealing protection system includes a liftable vacuum seal (6) configured to descend during casting to form a sealed chamber that accommodates at least the outlets (4) of the intermediate ladle (8) and the refining ladle (3) to isolate external air before and during casting. A weighing system (10) is installed on the vehicle platform (1) to monitor the weight data of the molten steel in the refining ladle (3) in real time; Temperature measurement system (11) is used to measure the temperature data of molten steel in the tundish (8) or in the pouring stream during the pouring process; A liquid level monitoring system (12) is used to monitor the liquid level height data of molten steel in the tundish (8) in real time; as well as The control system (13) is connected to the weighing system (10), the temperature measuring system (11), and the liquid level monitoring system (12) respectively, and is configured as follows: Based on the weight data, temperature data, and liquid level data, and in accordance with the preset pouring control logic, the opening of the flow regulating mechanism set at the outlet (4) of the refining ladle (3) is automatically adjusted to control the flow rate of molten steel flowing into the intermediate ladle (8).

2. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, The sealing protection system also includes a vacuum pump group and an inert gas storage tank, which are respectively connected to the sealed chamber through pipelines; the control system (13) is also configured to: selectively control the vacuum pump group to evacuate the sealed chamber before casting, or control the inert gas storage tank to fill the sealed chamber with inert gas to replace the air inside.

3. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, The sealed chamber is formed by the vacuum sealing cover (6) being tightly joined to the upper part of the vacuum cover (5) provided on the steel ingot mold (9) after it is lowered.

4. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, The weighing system (10) includes multiple weighing sensors, which are integrated between the vehicle platform (1) and the walking mechanism (2) or located below the trunnion support of the refining ladle (3) for real-time weighing of the total weight of the refining ladle (3) and the molten steel inside it.

5. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, The temperature measurement system (11) includes a multi-degree-of-freedom robotic arm fixed on the vehicle platform (1) and a temperature measuring element driven by it. The robotic arm responds to the instructions of the control system (13) and drives the temperature measuring element to automatically insert into a predetermined temperature measuring point in the intermediate package (8).

6. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, The liquid level monitoring system (12) includes a non-contact radar liquid level sensor or a laser liquid level sensor. The radar liquid level sensor or the laser liquid level sensor is installed inside the vacuum sealing cover (6), and the detection end faces the molten steel surface inside the tundish (8).

7. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, The preset pouring control logic includes a closed-loop main control loop based on the liquid level-time curve; the control system (13) is also configured to: compare the real-time liquid level height data fed back by the liquid level monitoring system (12) with the target value of the liquid level-time curve, and calculate the target opening adjustment amount required by the flow regulating mechanism in real time according to the deviation value.

8. The fully automatic vacuum casting system for steel ingots according to claim 7, characterized in that, The preset casting control logic also includes a closed-loop sub-control loop based on the weight-time curve; the control system (13) is further configured as follows: The instantaneous pouring flow rate of molten steel is calculated based on the real-time weight data fed back by the weighing system (10); The instantaneous pouring flow rate is compared with a preset safe flow rate threshold; as well as When the instantaneous pouring flow rate is lower than the safe flow rate threshold, it is determined to be a precursor to water blockage and an early warning signal is issued.

9. The fully automatic vacuum casting system for steel ingots according to claim 1, characterized in that, It also includes an argon control system (14), which is connected to the bottom blowing argon interface of the refining ladle (3); the control system (13) is also connected to the argon control system (14) by signal, and is further configured to: dynamically adjust the argon supply parameters of the argon control system (14) according to the comparison result between the real-time temperature data fed back by the temperature measurement system (11) and the preset target temperature range, so as to adjust the temperature drop rate of the molten steel in the refining ladle (3).

10. A closed-loop control method for a fully automatic vacuum casting system for steel ingots as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Move the casting system to the casting station via the vehicle platform (1) and control the vacuum sealing cover (6) to descend to form a sealed chamber; S2. Evacuate the sealed chamber or fill it with inert gas to replace the atmosphere in the sealed chamber with a protective atmosphere. S3. Turn on the flow regulation mechanism to start pouring into the tundish (8) and the ingot mold (9), and start real-time data acquisition, including at least: the weight data of the refining ladle (3) monitored by the weighing system (10), the temperature data of the molten steel measured by the temperature measurement system (11), and the liquid level height data in the tundish (8) measured by the liquid level monitoring system (12). S4. The control system (13) dynamically adjusts the opening of the flow regulating mechanism according to the collected liquid level height data and the preset liquid level-time closed-loop control curve to control the liquid level in the intermediate tank (8) to rise at a uniform speed according to the target speed. The control system (13) also calculates the instantaneous pouring flow rate according to the collected weight data and compares it with the preset safe flow rate threshold. When the instantaneous pouring flow rate is lower than the safe flow rate threshold, it determines that there is a risk of water blockage and issues a warning signal. S5. When the pouring reaches the preset termination condition, the flow regulation mechanism is closed to stop the pouring, and after maintaining the pressure under the protective atmosphere for a preset time, the vacuum sealing cover (6) is raised.

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