Multi-node pressure monitoring temper mill AGC hydraulic safety protection device and method

Abstract

The invention provides a multi-node pressure monitoring temper mill AGC hydraulic safety protection device and method, and relates to the field of cold-rolled sheet production equipment in the metallurgical industry. The problems that an existing AGC hydraulic system lacks real-time pressure monitoring, and a hydraulic cylinder is overloaded and exploded due to response delay of an overflow valve are solved. According to the device, through cooperative work of a triple pressure monitoring module, a signal processing module, a grading protection execution module and a reset self-checking module, three monitoring points are deployed at key nodes of a hydraulic loop, and rapid protection and fault positioning after pressure overrun are achieved in combination with millisecond-level signal processing and grading protection logic. According to the corresponding protection method, monitoring point installation, signal processing, protection triggering and system resetting are completed according to a standardized process. According to the invention, based on the redundancy design of triple pressure monitoring nodes and a millisecond-level response mechanism, comprehensive improvement of safety performance, operation benefits and system reliability is realized.

Description

Technical Field

[0001] This invention relates to the technical field of cold-rolled thin plate production equipment in the metallurgical industry, and in particular to a safety protection device and method for a leveling machine AGC hydraulic system based on multi-node pressure monitoring. Background Technology

[0002] The hydraulic system of the leveling machine's AGC (Automatic Gauge Control) is a core piece of equipment in the production of cold-rolled thin plates. It operates under full load for extended periods. Its hydraulic control circuit includes key components such as check valves, servo valves, electro-hydraulic check valves, and relief valves. The hydraulic cylinder end caps are secured with 20 M30×100 12.9 grade bolts, each with a tensile strength ≥1220MPa. Mechanical calculations confirm that the maximum pressure limit of the hydraulic cylinder is 245 bar.

[0003] In actual operation, the system is prone to various fault scenarios that lead to pressure over-limit: servo valve circuit board failure causing continuous pressure supply of 260 bar, mechanical damage to the servo valve causing the valve core to jam at the high-pressure position, and malfunction of the solenoid valve SV-51-3, etc. Traditional protection methods relying on relief valves have a response delay of ≥500ms, which cannot effectively protect against instantaneous pressure surges, easily leading to hydraulic cylinder overload and explosion, causing serious equipment damage and production losses. Therefore, there is an urgent need to develop a real-time monitoring and protection solution. Summary of the Invention

[0004] This invention aims to solve the problem of response delay caused by the lack of real-time pressure monitoring and reliance on a single relief valve protection in existing AGC hydraulic systems. It breaks through the limitations of traditional solutions in dealing with instantaneous pressure shocks and achieves accurate and rapid prevention and control of hydraulic cylinder overload risks.

[0005] To achieve the above objectives, the present invention provides a multi-node pressure monitoring hydraulic safety protection device for a leveling machine's AGC (Automatic Gauge Control) system, the device comprising:

[0006] The triple pressure monitoring module is used to monitor the pressure at three key monitoring points in the hydraulic system of the leveling machine's AGC in real time. The first pressure switch corresponding to the first monitoring point DC1 is set in the oil inlet line of the servo valve to monitor the pump source output pressure. The second pressure switch corresponding to the second monitoring point DC2 is set in the control oil circuit of the electro-hydraulic check valve to monitor the pilot pressure. The third pressure switch corresponding to the third monitoring point DC3 is set in the rodless chamber line of the hydraulic cylinder to directly monitor the load pressure.

[0007] The signal processing module is used to process and analyze the pressure signals from the three monitoring points collected by the triple pressure monitoring module.

[0008] The graded protection execution module is used to trigger graded safety protection actions based on the pressure signals from three monitoring points after processing and analysis, when the pressure signal of any of the three monitoring points is greater than the preset action pressure value and the duration is greater than or equal to the preset action duration.

[0009] The reset self-test module is used to perform a system safety reset after the fault has been cleared, and when the pressure signals at the three monitoring points are less than the preset stable pressure value and the duration meets the preset stable duration.

[0010] Preferably, the first pressure switch corresponding to the first monitoring point DC1 is set at the front end of the servo valve oil inlet pipeline and is integrated and installed through a T-shaped tee structure, with the tee threaded interface sealed by a combination gasket;

[0011] The second pressure switch corresponding to the second monitoring point DC2 is set at the pilot control port of the electro-hydraulic check valve. It is directly installed using the reserved G1 / 4 imperial pipe thread interface on the valve body and equipped with anti-vibration washers and lock nuts.

[0012] The third pressure switch corresponding to the third monitoring point DC3 is installed in the rodless chamber pipeline of the hydraulic cylinder. It is connected and installed through a high-pressure ball valve, a pressure testing connector and a high-pressure hose. The pipeline has a built-in pulse damper and a temperature compensation module.

[0013] Preferably, the signal processing module uses an independent AD acquisition module of an S7-1500F PLC to synchronously acquire pressure signals from three monitoring points at a frequency of 1kHz. After processing with a fourth-order Butterworth low-pass filter, the pressure values ​​of the three monitoring points are updated every millisecond, and cross-validation and pressure trend derivative analysis are performed between the three monitoring points.

[0014] Preferably, the step of triggering a graded safety protection action when the pressure signal at any of the three monitoring points is greater than a preset action pressure value and the duration is greater than a preset action duration includes:

[0015] When the pressure signal at any of the three monitoring points exceeds 233 bar and lasts for 5 ms or more, a graded safety protection action is triggered within 20 ms.

[0016] Preferably, the step of performing a system safety reset after the fault is cleared, and when the pressure signals at the three monitoring points are less than a preset stable pressure value and the duration meets the preset stable duration, includes:

[0017] After troubleshooting, and when the pressure signals at the three monitoring points are less than 220 bar and the duration is 60±5 seconds, perform a system safety reset.

[0018] Compared with existing technologies, the hydraulic safety protection device for a leveling machine AGC with multi-node pressure monitoring provided by this invention has the following beneficial effects: This invention utilizes a triple pressure monitoring module to monitor the pressure at three monitoring points in the critical circuit of the leveling machine AGC hydraulic system in real time. A signal processing module processes and analyzes the pressure signals from the three monitoring points collected by the triple pressure monitoring module. A graded protection execution module, based on the processed and analyzed pressure signals from the three monitoring points, triggers graded safety protection actions when the pressure signal at any of the three monitoring points exceeds a preset action pressure value and the duration is greater than or equal to a preset action duration. A reset self-test module performs a system safety reset after fault clearance, when the pressure signals at the three monitoring points are less than a preset stable pressure value and the duration meets the preset stable duration. This invention employs a triple pressure redundancy design and a graded protection mechanism, combined with millisecond-level signal acquisition and processing logic, to achieve rapid power-off, emergency pressure relief, and fault alarm after pressure overload, effectively preventing hydraulic cylinder overload damage and reducing downtime and spare parts consumption.

[0019] This invention also provides a hydraulic safety protection method for AGC (Automatic Gauge Control) of a leveling machine with multi-node pressure monitoring, the method comprising:

[0020] Step S1: Install, seal, and protect the pressure switches at the three monitoring points of the critical circuit of the leveling machine's AGC hydraulic system, and perform three-point in-situ calibration and zero-point drift compensation. Use the installed pressure switches to monitor the pressure at the three monitoring points of the critical circuit of the leveling machine's AGC hydraulic system in real time. The first pressure switch corresponding to the first monitoring point DC1 is installed in the servo valve inlet pipeline to monitor the pump source output pressure; the second pressure switch corresponding to the second monitoring point DC2 is installed in the electro-hydraulic check valve control oil circuit to monitor the pilot pressure; and the third pressure switch corresponding to the third monitoring point DC3 is installed in the rodless chamber pipeline of the hydraulic cylinder to directly monitor the load pressure.

[0021] Step S2: Process and analyze the pressure signals collected from the three monitoring points;

[0022] Step S3: Based on the pressure signals from the three monitoring points after processing and analysis, when the pressure signal of any of the three monitoring points is greater than the preset action pressure value and the duration is greater than or equal to the preset action duration, the graded safety protection action is triggered.

[0023] Step S4: After troubleshooting, if the pressure signals at the three monitoring points are less than the preset stable pressure value and the duration meets the preset stable duration, perform a system safety reset.

[0024] Preferably, the first pressure switch corresponding to the first monitoring point DC1 is set at the front end of the servo valve oil inlet pipeline and is integrated and installed through a T-shaped tee structure, with the tee threaded interface sealed by a combination gasket;

[0025] The second pressure switch corresponding to the second monitoring point DC2 is set at the pilot control port of the electro-hydraulic check valve. It is directly installed using the reserved G1 / 4 imperial pipe thread interface on the valve body and equipped with anti-vibration washers and lock nuts.

[0026] The third pressure switch corresponding to the third monitoring point DC3 is installed in the rodless chamber pipeline of the hydraulic cylinder. It is connected and installed through a high-pressure ball valve, a pressure testing connector and a high-pressure hose. The pipeline has a built-in pulse damper and a temperature compensation module.

[0027] Preferably, step S2: processing and analyzing the pressure signals from the three monitoring points includes: using an independent AD acquisition module of an S7-1500F PLC to synchronously acquire the pressure signals from the three monitoring points at a frequency of 1kHz; processing the signals using a fourth-order Butterworth low-pass filter; updating the pressure values ​​of the three monitoring points every millisecond; and performing cross-validation and pressure trend derivative analysis between the three monitoring points.

[0028] Preferably, in step S3, triggering the graded safety protection action when the pressure signal of any of the three monitoring points is greater than the preset action pressure value and the duration is greater than the preset action duration includes: triggering the graded safety protection action within 20ms when the pressure signal of any of the three monitoring points is greater than 233 bar and the duration is greater than or equal to 5ms.

[0029] Preferably, in step S4, after the fault is cleared, and the pressure signals at the three monitoring points are less than the preset stable pressure value and the duration meets the preset stable duration, a system safety reset is performed, including: after the fault is cleared, and the pressure signals at the three monitoring points are less than 220 bar and the duration is 60±5 seconds, a system safety reset is performed.

[0030] Compared with the prior art, the beneficial effects of the multi-node pressure monitoring hydraulic safety protection method for AGC of a leveling machine provided by the present invention are the same as the beneficial effects of the multi-node pressure monitoring hydraulic safety protection device for AGC of a leveling machine provided by the above-mentioned technical solutions, and will not be repeated here.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This diagram illustrates the structure of a multi-node pressure monitoring hydraulic safety protection device for a leveling machine AGC, provided in an embodiment of the present invention.

[0034] Figure 2 The flowchart illustrates a hydraulic safety protection method for a leveling machine AGC with multi-node pressure monitoring, provided by an embodiment of the present invention. Detailed Implementation

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] Figure 1 This diagram illustrates the structure of a multi-node pressure monitoring hydraulic safety protection device for a leveling machine's AGC, as provided in an embodiment of the present invention. Figure 1 As shown, the device includes:

[0038] The triple pressure monitoring module 1 is used to monitor the pressure at three key monitoring points in the hydraulic system of the leveling machine AGC in real time. The first pressure switch corresponding to the first monitoring point DC1 is set in the oil inlet line of the servo valve to monitor the output pressure of the pump source; the second pressure switch corresponding to the second monitoring point DC2 is set in the control oil circuit of the electro-hydraulic check valve to monitor the pilot pressure; and the third pressure switch corresponding to the third monitoring point DC3 is set in the rodless chamber line of the hydraulic cylinder to directly monitor the load pressure.

[0039] It should be noted that the first pressure switch corresponding to the first monitoring point DC1 is installed at the front end of the servo valve's oil inlet pipeline. Specifically, it is integrated and installed using a T-type tee structure adapted to a Φ22mm high-pressure seamless steel pipe. A high-pressure tee connector is added to the existing pipeline. The tee's pressure rating is ≥400 bar. The horizontal end of the tee is connected to the system pipeline, and the pressure switch is installed at the vertical end. The threaded interface of the tee is sealed with a combination gasket, or 316 stainless steel + graphite spiral wound gasket can be used for sealing to ensure no pressure pulsation leakage.

[0040] The second pressure switch corresponding to the second monitoring point DC2 is set at the pilot control port of the electro-hydraulic check valve. The pressure switch is directly installed using the reserved G1 / 4 imperial pipe thread interface on the valve body. During installation, the angle between the sensor axis and the horizontal plane is ≥60°. It is equipped with a shock-resistant washer with a vibration-resistant frequency range of 5-2000Hz and a locking nut with a torque of 35±2N・m.

[0041] The third pressure switch corresponding to the third monitoring point DC3 is installed in the rodless chamber pipeline of the hydraulic cylinder. It is installed using a high-pressure ball valve, pressure testing connector, and high-pressure hose adapter. The pipeline incorporates a pulse damper and a temperature compensation module. Specifically, a three-stage adapter structure is used: ① A 6mm diameter high-pressure ball valve is installed at the pressure testing port of the hydraulic cylinder body; ② The ball valve outlet is connected to a pressure testing connector of model HMP-06; ③ The pressure testing connector is connected to the pressure switch via a high-pressure hose with a length ≤300mm and a burst pressure ≥600bar. A dynamic temperature compensation design is adopted. Specifically, a pulse damper with a volume of 15cm³ and an attenuation rate ≥85% and a temperature compensation module are installed in the pressure testing pipeline to suppress measurement fluctuations caused by pressure shocks. Table 1 describes the technical characteristics of the three monitoring points.

[0042] Table 1 Technical characteristics of the three monitoring points

[0043] monitoring points Installation structure features Pressure-bearing component specifications Dynamic response optimization measures DC1 T-type three-way bypass detection T-joint wall thickness ≥ 4.5mm Reduce the detection chamber volume to 3.2 cm³ DC2 Straight thread in-situ installation Thread engagement length ≥ 8mm Built-in 0.2μm filter DC3 flexible hose vibration isolation adapter Hose burst pressure ≥600 bar Pulse damper + temperature compensation module

[0044] Furthermore, the pressure switch installation process also includes the following key points: (1) Cleanliness control: Before installation, use NAS1638 Class 6 hydraulic oil to flush the pipeline, and wipe the interface end face with acetone to remove grease. (2) Calibration benchmark: After the pressure switch is installed, it needs to be calibrated in place. Calibration points: 50 / 150 / 220 bar, to ensure that the zero drift compensation value is ≤±0.3%FS / year. (3) Mechanical protection: Install a stamped steel plate protective cover with a thickness of 1.5mm, and configure an IP67 waterproof connector at the cable inlet.

[0045] Three pressure switches monitor the pump source pressure, pilot pressure, and load pressure respectively, covering key nodes in the hydraulic circuit. Combined with sealing, vibration resistance, and dynamic compensation design, accurate and stable measurement is ensured under complex working conditions.

[0046] Signal processing module 2 is used to process and analyze the pressure signals from the three monitoring points collected by triple pressure monitoring module 1.

[0047] It should be noted that signal processing module 2 uses an independent AD acquisition module of an S7-1500F PLC to synchronously acquire pressure signals from three monitoring points DC1 / DC2 / DC3 at a frequency of 1kHz. Table 2 shows the specific sampling parameters. The signals are processed using a fourth-order Butterworth low-pass filter with a cutoff frequency of 100Hz. The pressure values ​​of the three monitoring points are updated every millisecond, and cross-validation and pressure trend derivative analysis are performed between the three monitoring points. The specific data processing flow is as follows: update the pressure values ​​of the three channels every millisecond → perform cross-validation between channels with a tolerance of ±1.5 bar → generate pressure trend derivative dP / dt monitoring.

[0048] Table 2 Sampling parameters of the signal processing module

[0049] sampling frequency Signal filtering Measuring range 1kHz (period 1ms) Fourth-order Butterworth low-pass filter (cutoff frequency 100Hz) 0-400 bar

[0050] By using an S7-1500F PLC as the core, and through high-frequency acquisition, filtering, cross-validation, and trend analysis, effective pressure signals and abnormal fluctuations can be quickly identified, providing a reliable basis for protection actions.

[0051] The graded protection execution module 3 is used to trigger graded safety protection actions based on the pressure signals of the three monitoring points after processing and analysis. When the pressure signal of any of the three monitoring points is greater than the preset action pressure value and the duration is greater than or equal to the preset action duration, the graded protection action is triggered.

[0052] It should be noted that the triggering condition for the tiered protection mechanism is: (P x >233bar)∩(Δt≥5ms). Where: P x =max(DC1,DC2,DC3), Δt = over-limit duration. The protection action sequence is completed within 20ms after the conditions are met. That is, when the pressure signal at any of the three monitoring points is greater than 233 bar and the duration is greater than or equal to 5ms, the graded safety protection action is triggered within 20ms. Table 3 is the protection action sequence table.

[0053] Table 3 Protective Action Sequence

[0054] Action sequence Execution content Technical parameters Action 1 After outputting the DO signal to relay K1, the 24VDC power supply to the servo valve is cut off. Response time: ≤3ms; Contact capacity: 10A / 250VAC Action 2 Start the ER-20 emergency pressure relief valve Full-open stroke time ≤15ms, discharge flow rate: 80L / min@300bar, pilot control pressure: 10bar Action 3 Triggering HMI red alarm screen Display: Fault location (DC1 / DC2 / DC3 highlighted)

[0055] By setting scientific triggering conditions, the protection actions are executed in the sequence of "power failure-pressure relief-alarm" to ensure that the risk source is cut off in a very short time, while simultaneously locating the fault.

[0056] The reset self-test module 4 is used to perform a system safety reset after the fault is cleared, and when the pressure signals of the three monitoring points are less than the preset stable pressure value and the duration meets the preset stable duration.

[0057] It should be noted that the reset prerequisite is that the pressure of all three channels is stable at the safety threshold <220 bar for 60±5 seconds, allowing the reset process to be started, the pressure relief valve ER-20 is confirmed to be closed, and feedback is obtained using the valve position sensor. That is to say, after the fault is eliminated, and the pressure signal of the three monitoring points is less than 220 bar for 60±5 seconds, the system is safely reset. The reset operation process is as follows: (1) The operator clicks the "Fault Reset" button on the HMI to perform the reset operation. (2) The PLC performs system self-check: zero-point calibration of the pressure sensor, deviation <±0.5%FS, impedance detection of the servo valve coil, range 22Ω±10%. (3) The operator visually checks the hydraulic cylinder to confirm that there is no leakage. (4) Press the reset button of the control cabinet, which adopts a double interlock design. Safety interlock: The pressure is continuously monitored during the reset process. If the pressure of any channel is >210 bar, the reset is immediately stopped. By establishing multiple reset prerequisites and self-check processes, blind reset is avoided when the fault is not eliminated, ensuring the safety of secondary operation.

[0058] Compared with the prior art, the hydraulic safety protection device for AGC of a leveling machine with multi-node pressure monitoring provided in this embodiment of the invention has the following beneficial effects:

[0059] 1. It adopts a redundant design of triple real-time pressure monitoring nodes DC1 / DC2 / DC3, which directly targets the overload protection of hydraulic cylinders, and the dynamic response time is ≤10ms, which is faster than its pressure compensation mechanism and 50 times faster than its relief valve response speed. It also adds cross-validation and trend derivative analysis dP / dt to improve the fault location accuracy.

[0060] 2. Through a three-node trigger logic, protection is activated when the pressure at any monitoring point exceeds 233 bar, breaking through the limitation of a single threshold control. Combined with a graded protection mechanism, the power supply is cut off, emergency pressure relief and alarm are linked within 20ms, completely eliminating the risk of hydraulic cylinder explosion. In addition, a reset self-test process is added, such as servo valve impedance detection, to avoid misoperation.

[0061] 3. The hardware layer integrates real-time monitoring and protection logic. Pressure switches are deployed in the servo valve inlet oil circuit DC1, pilot oil circuit DC2 and rodless chamber DC3 of the hydraulic cylinder. The signal stability is ensured by pulse damper and anti-vibration design, and the action threshold is precisely set based on the mechanical limit of the bolt, which solves the delay problem of traditional relief valve.

[0062] This invention also provides a hydraulic safety protection method for AGC (Automatic Gauge Control) of a leveling machine with multi-node pressure monitoring. Figure 2The flowchart illustrates a hydraulic safety protection method for a leveling machine AGC with multi-node pressure monitoring, provided by an embodiment of the present invention. Figure 2 As shown, the method includes:

[0063] Step S1: Install, seal, and protect the pressure switches at the three monitoring points of the critical circuit of the leveling machine's AGC hydraulic system, and perform three-point in-situ calibration and zero-point drift compensation. Use the installed pressure switches to monitor the pressure at the three monitoring points of the critical circuit of the leveling machine's AGC hydraulic system in real time. The first pressure switch corresponding to the first monitoring point DC1 is set in the servo valve inlet pipeline to monitor the pump source output pressure; the second pressure switch corresponding to the second monitoring point DC2 is set in the electro-hydraulic check valve control oil circuit to monitor the pilot pressure; and the third pressure switch corresponding to the third monitoring point DC3 is set in the rodless chamber pipeline of the hydraulic cylinder to directly monitor the load pressure.

[0064] It should be noted that the first pressure switch corresponding to the first monitoring point DC1 is located at the front end of the servo valve's main oil inlet pipeline. Installation location: Front end of the servo valve's main oil inlet pipeline. Pipe specifications: Φ22mm high-pressure seamless steel pipe. Installation method: Integrated installation using a T-type tee structure; a high-pressure tee connector is added to the existing pipeline, with a pressure rating ≥400 bar. The horizontal end of the tee connects to the system pipeline, and the pressure switch is installed at the vertical end. Sealing treatment: The tee threaded interface uses a combination gasket seal; material: 316 stainless steel + graphite spiral wound gasket, ensuring no leakage under pressure pulsation conditions.

[0065] The second pressure switch corresponding to the second monitoring point DC2 is located at the pilot control port of the electro-hydraulic check valve. Interface specification: ISO 228 standard G1 / 4 imperial pipe thread. Installation method: After removing the original plug, directly thread the pressure switch, utilizing the pre-reserved pressure measurement interface on the valve body to achieve zero-pipeline modification. During installation, ensure the angle between the sensor axis and the horizontal plane is ≥60° to prevent air bubble accumulation. Vibration protection measures: Install a miniature hydraulic locking nut with a torque value of 35±2 N·m, and configure anti-vibration washers with a vibration resistance frequency range of 5-2000Hz.

[0066] The third pressure switch corresponding to the third monitoring point DC3 is located in the rodless chamber pipeline of the hydraulic cylinder. Connection scheme: A three-stage connection structure is adopted: ① A high-pressure ball valve is installed at the pressure testing port of the hydraulic cylinder body, with a nominal diameter of 6mm. ② The ball valve outlet is connected to a pressure testing connector, model: HMP-06. ③ The pressure testing connector is connected to the pressure switch via a high-pressure hose with a length ≤300mm. Dynamic compensation design: A pulse damper with a volume of 15cm³ is installed in the pressure testing pipeline to suppress measurement fluctuations caused by pressure shocks, ensuring an attenuation rate ≥85%.

[0067] Table 1 describes the technical characteristics of the three monitoring points.

[0068] Table 1 Technical characteristics of the three monitoring points

[0069] monitoring points Installation structure features Pressure-bearing component specifications Dynamic response optimization measures DC1 T-type three-way bypass detection T-joint wall thickness ≥ 4.5mm Reduce the detection chamber volume to 3.2 cm³ DC2 Straight thread in-situ installation Thread engagement length ≥ 8mm Built-in 0.2μm filter DC3 flexible hose vibration isolation adapter Hose burst pressure ≥600 bar Pulse damper + temperature compensation module

[0070] Key points of installation process (1) Cleanliness control: Before installation, flush the pipeline with NAS1638 Class 6 hydraulic oil and wipe the interface end face with acetone to remove grease. (2) Calibration benchmark: The pressure switch needs to be calibrated in place after installation. Calibration points: 50 / 150 / 220 bar, zero drift compensation value ≤ ±0.3%FS / year. (3) Mechanical protection: Install a stamped steel plate protective cover with a thickness of 1.5mm, and configure an IP67 waterproof connector at the cable inlet.

[0071] Step S2: Process and analyze the pressure signals collected from the three monitoring points.

[0072] It should be noted that an independent AD acquisition module of an S7-1500F PLC was used to synchronously acquire pressure signals from three monitoring points (DC1 / DC2 / DC3) at a frequency of 1kHz. Table 2 shows the specific sampling parameters. A fourth-order Butterworth low-pass filter was used for processing, with a cutoff frequency of 100Hz. The pressure values ​​of the three monitoring points were updated every millisecond, and cross-validation and pressure trend derivative analysis were performed between the three monitoring points. The specific data processing flow is as follows: update the pressure values ​​of the three channels every millisecond → perform cross-validation between channels with a deviation tolerance of ±1.5 bar → generate pressure trend derivative dP / dt monitoring.

[0073] Table 2 Sampling parameters of the signal processing module

[0074] sampling frequency Signal filtering Measuring range 1kHz (period 1ms) Fourth-order Butterworth low-pass filter (cutoff frequency 100Hz) 0-400 bar

[0075] Step S3: Based on the pressure signals from the three monitoring points after processing and analysis, when the pressure signal of any of the three monitoring points is greater than the preset action pressure value and the duration is greater than or equal to the preset action duration, the graded safety protection action is triggered.

[0076] It should be noted that the trigger condition for the graded protection mechanism is expressed mathematically as: trigger condition = (P x > 233bar)∩(Δt≥5ms). Where: P x =max(DC1,DC2,DC3), Δt = over-limit duration. The protection action sequence is completed within 20ms after the conditions are met. That is, when the pressure signal at any of the three monitoring points is greater than the preset action pressure value and the duration is greater than the preset action duration, the graded safety protection action is triggered, including: when the pressure signal at any of the three monitoring points is greater than 233 bar and the duration is greater than or equal to 5ms, the graded safety protection action is triggered within 20ms. Table 3 is the protection action sequence table.

[0077] Table 3 Protective Action Sequence

[0078] Action sequence Execution content Technical parameters Action 1 After outputting the DO signal to relay K1, the 24VDC power supply to the servo valve is cut off. Response time: ≤3ms; Contact capacity: 10A / 250VAC Action 2 Start the ER-20 emergency pressure relief valve Full-open stroke time ≤15ms, discharge flow rate: 80L / min@300bar, pilot control pressure: 10bar Action 3 Triggering HMI red alarm screen Display: Fault location (DC1 / DC2 / DC3 highlighted)

[0079] Specifically, when the pressure value at any monitoring node is >233 bar and the duration is ≥5 ms, the following actions will be performed sequentially within 20 ms after triggering: 1. Cut off the 24VDC power supply to the servo valve, with a response time ≤3 ms and a contact capacity of 10A / 250VAC. 2. Activate the ER-20 emergency pressure relief valve, with a full opening stroke time ≤15 ms and a relief flow rate of 80 L / min @ 300 bar. 3. Trigger a red alarm on the HMI and highlight the fault point.

[0080] Step S4: After troubleshooting, if the pressure signals at the three monitoring points are less than the preset stable pressure value and the duration meets the preset stable duration, perform a system safety reset.

[0081] It should be noted that the prerequisite for reset is that the pressure of all three channels is stable at the safety threshold <220 bar for 60±5 seconds, and the pressure relief valve ER-20 is confirmed to be closed, and the valve position sensor provides feedback. The reset operation process includes: (1) The operator clicks the "Fault Reset" button on the HMI. (2) The PLC performs a system self-test: zero-point calibration of the pressure sensor, deviation <±0.5%FS, and impedance detection of the servo valve coil at 22Ω±10%. (3) The operator visually inspects the site to confirm that there is no leakage in the hydraulic cylinder. (4) The operator presses the reset button on the control cabinet, which adopts a double interlock design. Safety interlock: The pressure is continuously monitored during the reset process. If the pressure of any channel is >210 bar, the reset is immediately stopped. That is to say, after the fault is cleared, and the pressure signal of the three monitoring points is less than the preset stable pressure value, and the duration meets the preset stable duration, the system is safely reset, including: after the fault is cleared, and the pressure signal of the three monitoring points is less than 220 bar, and the duration is 60±5 seconds, the system is safely reset.

[0082] Compared with the prior art, the hydraulic safety protection method for AGC of a leveling machine with multi-node pressure monitoring provided by the embodiments of the present invention has the following beneficial effects:

[0083] 1. This invention utilizes DC1 to monitor pump source pressure, DC2 to monitor pilot pressure, and DC3 to monitor load pressure. Through ultra-high-speed response of pressure switch (≤10ms) and precise threshold setting of 233bar, it can effectively solve the problem of hydraulic cylinder overload and cylinder explosion caused by the 500ms delay of traditional relief valve. The action threshold is set to 233bar (95% of the ultimate pressure), which avoids overload risk and reserves a reasonable safety margin.

[0084] 2. Triple node redundancy design, cross-checking mechanism and anti-seismic and anti-leakage technology ensure stable operation under complex working conditions.

[0085] 3. Industrial measured annual downtime due to failure is reduced by 85%, losses from a single accident are avoided by more than 500,000 yuan, hydraulic cylinder spare parts wear is reduced by 70%, and downtime due to modification is less than 4 hours.

[0086] 4. The hardware can achieve "zero pipeline modification" by utilizing the equipment's reserved interface, is compatible with mainstream leveling machine AGC systems, and can be migrated to high-pressure hydraulic scenarios such as aluminum plate rolling mills and continuous casting machines.

[0087] In addition, this invention also provides an electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor. The transceiver, the memory, and the processor are connected via the bus. When the computer program is executed by the processor, it implements the various processes of the above-described embodiment of a multi-node pressure monitoring method for hydraulic safety protection of a leveling machine AGC, and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0088] Furthermore, this embodiment of the invention also provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the various processes of the above-described embodiment of a multi-node pressure monitoring method for hydraulic safety protection of a leveling machine AGC, and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0089] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations 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. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-node pressure monitoring calender AGC hydraulic safety protection device, characterized in that, Comprise: Triple pressure monitoring module for real-time monitoring of the pressure of three monitoring points of the key loop of the AGC hydraulic system of the leveler, the first monitoring point DC1 corresponding to the first pressure switch, arranged at the servo valve inlet oil pipeline, for monitoring the pump output pressure; the second monitoring point DC2 corresponding to the second pressure switch, arranged at the electro-hydraulic one-way valve control oil path, for monitoring the pilot pressure; the third monitoring point DC3 corresponding to the third pressure switch, arranged at the hydraulic cylinder rodless cavity pipeline, for directly monitoring the load pressure; Signal processing module for processing and analyzing the pressure signals of the three monitoring points collected by the triple pressure monitoring module; Hierarchical protection execution module for triggering hierarchical safety protection actions based on the pressure signals of the three monitoring points after processing and analysis, when the pressure signal of any one of the three monitoring points is greater than the preset action pressure value, and the duration is greater than or equal to the preset action duration; Reset self-checking module for system safety reset after troubleshooting, when the pressure signals of the three monitoring points are less than the preset stable pressure value, and the duration meets the preset stable duration.

2. The AGC hydraulic safety protection device of the leveler with multiple node pressure monitoring according to claim 1, characterized in that: The first pressure switch corresponding to the first monitoring point DC1 is arranged at the front end of the servo valve inlet oil pipeline and integrated by a T-shaped tee structure, and the tee threaded interface is sealed by a combination gasket; The second pressure switch corresponding to the second monitoring point DC2 is arranged at the pilot control oil port of the electro-hydraulic one-way valve, directly installed by a G1 / 4 inch pipe threaded interface reserved in the valve body, and configured with an anti-vibration gasket and a locking nut; The third pressure switch corresponding to the third monitoring point DC3 is arranged at the hydraulic cylinder rodless cavity pipeline, installed by a high-pressure ball valve, a pressure measuring connector and a high-pressure hose, and the pipeline is internally provided with a pulse damper and a temperature compensation module.

3. The AGC hydraulic safety protection device of the leveler with multiple node pressure monitoring according to claim 1, characterized in that: The signal processing module adopts an independent AD acquisition module of S7-1500F PLC to synchronously acquire the pressure signals of the three monitoring points at a frequency of 1 kHz, and after low-pass filtering processing by a fourth-order Butterworth filter, the pressure values of the three monitoring points are updated every millisecond, and cross verification and pressure trend derivative analysis among the three monitoring points are performed.

4. The AGC hydraulic safety protection device of the leveler with multiple node pressure monitoring according to claim 1, characterized in that: When the pressure signal of any one of the three monitoring points is greater than the preset action pressure value, and the duration is greater than the preset action duration, the hierarchical safety protection action is triggered, which comprises: When the pressure signal of any one of the three monitoring points is greater than 233 bar, and the duration is greater than or equal to 5 ms, the hierarchical safety protection action is triggered within 20 ms.

5. The AGC hydraulic safety protection device of the leveler with multiple node pressure monitoring according to claim 1, characterized in that: The system safety reset is performed when the pressure signals of the three monitoring points are less than the preset stable pressure value after troubleshooting, and the duration meets the preset stable duration. The system safety reset is performed when the pressure signals of the three monitoring points are less than 220 bar after troubleshooting, and the duration is 60±5 seconds.

6. A multi-node pressure monitoring calender AGC hydraulic safety protection method, characterized in that, The method comprises the following steps: Step S1: Install, seal and protect the pressure switches of the three monitoring points of the key circuit of the AGC hydraulic system of the leveler, and perform in-situ calibration and zero drift compensation. The pressure of the three monitoring points of the key circuit of the AGC hydraulic system of the leveler is monitored in real time through the installed pressure switches. The first pressure switch corresponding to the first monitoring point DC1 is arranged on the servo valve inlet pipeline to monitor the pump output pressure. The second pressure switch corresponding to the second monitoring point DC2 is arranged on the electro-hydraulic check valve control oil circuit to monitor the pilot pressure. The third pressure switch corresponding to the third monitoring point DC3 is arranged on the hydraulic cylinder rodless cavity pipeline to directly monitor the load pressure. Step S2: Process and analyze the collected pressure signals of the three monitoring points. Step S3: Based on the processed and analyzed pressure signals of the three monitoring points, when the pressure signal of any one of the three monitoring points is greater than the preset action pressure value, and the duration is greater than or equal to the preset action duration, the hierarchical safety protection action is triggered. Step S4: The system safety reset is performed when the pressure signals of the three monitoring points are less than the preset stable pressure value after troubleshooting, and the duration meets the preset stable duration.

7. The AGC hydraulic safety protection method of the leveler with multi-node pressure monitoring according to claim 6, wherein the first pressure switch corresponding to the first monitoring point DC1 is arranged at the front end of the servo valve inlet pipeline and is integrated and installed through a T-shaped three-way structure, and the three-way threaded interface is sealed by a combination gasket; the second pressure switch corresponding to the second monitoring point DC2 is arranged on the pilot control oil port of the electro-hydraulic check valve, is directly installed by using the reserved G1 / 4 inch pipe threaded interface of the valve body, and is configured with an anti-vibration gasket and a locking nut; the third pressure switch corresponding to the third monitoring point DC3 is arranged on the hydraulic cylinder rodless cavity pipeline, is installed through a high-pressure ball valve, a pressure measuring connector and a high-pressure hose, and the pipeline is internally provided with a pulse damper and a temperature compensation module.

8. The AGC hydraulic safety protection method of the leveler with multi-node pressure monitoring according to claim 6, wherein the step S2: processing and analyzing the collected pressure signals of the three monitoring points comprises: an independent AD acquisition module of an S7-1500F PLC is used to synchronously acquire the pressure signals of the three monitoring points at a frequency of 1 kHz, and after being processed by a fourth-order Butterworth low-pass filter, the pressure values of the three monitoring points are updated every millisecond, and cross verification and pressure trend derivative analysis among the three monitoring points are performed.

9. The AGC hydraulic safety protection method of the leveler with multi-node pressure monitoring according to claim 6, wherein ​ ​ The step S3, when the pressure signal of any one of the three monitoring points is greater than the preset action pressure value, and the duration is greater than the preset action duration, triggering the hierarchical safety protection action, comprising: When the pressure signal of any one of the three monitoring points is greater than 233 bar, and the duration is greater than or equal to 5 ms, triggering the hierarchical safety protection action within 20 ms.

10. The multi-node pressure monitoring calender AGC hydraulic safety protection method according to claim 6, characterized in that, In the step S4, after troubleshooting, and the pressure signal of the three monitoring points is less than the preset stable pressure value, and the duration meets the preset stable duration, the system safety is reset, comprising: After troubleshooting, and the pressure signal of the three monitoring points is less than 220 bar, and the duration is 60±5 seconds, the system safety is reset.

Images