Axial pressure displacement self-adaptive main steam valve adjusting screw ring dismounting system and method

Abstract

This invention relates to the field of steam turbine assembly technology, specifically to a system and method for disassembling and assembling a main steam valve regulating threaded ring based on axial pressure displacement adaptation. The system includes a screwing assembly, an axial pressure application unit, and a pressure adaptive control system. The pressure adaptive control system is configured to adjust the output pressure of the axial pressure application unit in real time according to the screwing state of the threaded ring. It includes a pressure monitoring module for real-time monitoring of the actual axial pressure applied to the valve cover by the axial pressure application unit, a torque monitoring module for real-time monitoring of the rotational resistance torque when the screwing assembly drives the threaded ring, and a central controller. During disassembly, the central controller controls the axial pressure application unit to gradually apply pressure while simultaneously monitoring the rotational resistance torque. When a step-down characteristic of the rotational resistance torque is detected, it is determined that the threaded ring has disengaged from the compressed state. The central controller immediately instructs the axial pressure application unit to stop pressurizing or switch to a low-pressure holding mode, thereby improving the service life of the valve body and the threaded ring.

Description

Technical Field

[0001] This invention relates to the field of steam turbine assembly technology, specifically to a system and method for disassembling and assembling the main steam valve adjusting thread ring based on axial pressure displacement adaptive. Background Technology

[0002] Currently, when overhauling and maintaining ultra-supercritical coal-fired power generating units, the common practice on-site for disassembling and assembling the threaded rings of the main steam valve and regulating valve is the hammer impact method. This involves using a specially designed wrench on the threaded ring, and then manually or mechanically driving a heavy hammer to apply a momentary impact force to the wrench handle, thereby generating rotational torque to loosen or tighten the threaded ring.

[0003] However, in practical applications, traditional impact disassembly methods have the following significant drawbacks: The main steam valves and regulating valves of coal-fired power generating units are subjected to extremely high temperatures and pressures during operation. Under the combined effects of high-temperature oxidation and thermal expansion and contraction, the mating threads between the threaded ring and the valve body are prone to metal creep or oxidative adhesion. If a hammer is used for violent impact disassembly, the instantaneous impact load can easily lead to uneven stress on the thread profile, causing surface damage, burrs, or even instantaneous jamming or seizing. Once the threaded ring seizes, destructive cutting is often required for removal, significantly extending the maintenance period and increasing repair costs.

[0004] During assembly, the impact of the hammer cannot precisely control the torque applied to the threaded ring. Operators often rely on experience to judge the tightness, making it difficult to quantify the preload. This easily leads to insufficient assembly force on the threaded ring, failing to achieve the designed sealing pressure. After the unit is put into operation, facing the impact of high-pressure steam, the threaded ring with insufficient preload is prone to steam leakage, which not only reduces the unit's thermal efficiency but also poses a significant safety hazard to on-site equipment and personnel. Summary of the Invention

[0005] The purpose of this invention is to provide a disassembly and assembly system for the main steam valve regulating valve threaded ring during the assembly process of a steam turbine. By constructing an intelligent control mechanism based on torque-pressure coupling feedback, the critical unloading point of threaded ring loosening is captured in real time during operation, thereby achieving precise quantification of axial pressure and minimum necessary pressure control, completely eliminating the risk of equipment damage caused by experience-based operation, and realizing adaptive closed-loop safety protection for the main steam valve and the internal components of the regulating valve.

[0006] To achieve the above objectives, the first aspect of the present invention provides a main steam valve adjusting ring disassembly and assembly system with adaptive axial pressure displacement, comprising a screwing assembly, an axial pressure application unit, and a pressure adaptive control system. The screwing assembly is used to drive the threaded ring to rotate; The axial pressure unit is configured to apply axial pressure to the valve cover using a power component through a sleeve arranged coaxially with the valve stem. The pressure adaptive control system is configured to adjust the output pressure of the axial pressure unit in real time according to the screwing state of the threaded ring. It includes a pressure monitoring module for real-time monitoring of the actual axial pressure value applied to the valve cover by the axial pressure unit, a torque monitoring module for real-time monitoring of the rotational resistance torque when the screwing assembly drives the threaded ring, and a central controller. The central controller is communicatively connected to the pressure monitoring module, the torque monitoring module and the power component of the axial pressure unit. The central controller is equipped with critical unloading judgment logic: during the disassembly process, the central controller controls the axial pressure unit to gradually apply pressure while monitoring the rotational resistance torque; when the rotational resistance torque is detected to have a step-down characteristic, it is determined that the threaded ring has been released from the clamping state, and the central controller immediately instructs the axial pressure unit to stop pressurizing or switch to low-pressure holding mode.

[0007] Preferably, the pressure regulation logic of the central controller includes: During the trial phase, the axial pressure unit is controlled to increase pressure in a stepped manner with a preset pressure step size; Coupling detection involves controlling the screwing assembly to output a trial torque with a set threshold at each pressure step. Adaptive locking: If the trial torque fails to drive the threaded ring to rotate, proceed to the next pressure step; if the threaded ring rotates and the torque value is lower than the set threshold, mark the current axial pressure value as the effective unloading pressure and lock the output of the axial pressure unit so that it will not increase the pressure during subsequent unscrewing.

[0008] Preferably, the turning assembly includes a hydraulic cylinder or a servo electric cylinder as the drive source; the torque monitoring module is a pressure sensor integrated in the hydraulic circuit of the drive source, or a dynamic torque sensor connected in series on the drive transmission chain; the central controller obtains the rotational resistance torque by calculating the pressure change of the drive source or by directly reading the sensor value.

[0009] Preferably, the tightening assembly includes a pipe thread wrench, a telescopic component, and a mounting bracket for mounting on the equipment housing. The fixed end of the telescopic component is connected to the mounting bracket, and the telescopic end of the telescopic component is connected to the pipe thread wrench.

[0010] Preferably, the axial pressure unit includes a bracket, a sleeve, and a power component. The bracket is mounted on the equipment housing, the sleeve is coaxially arranged with the valve stem of the equipment, and the end of the sleeve is provided with a pressure-bearing end face for contacting the valve cover. The power component is arranged between the sleeve and the bracket and is used to apply axial pressure to the valve cover through the sleeve.

[0011] Preferably, the pipe thread wrench includes a wrench body and an extension arm extending outward from the wrench body, with the telescopic end of the telescopic component connected to the extension arm.

[0012] A second aspect of the present invention provides a method for disassembling and assembling the main steam valve adjusting valve threaded ring using the above-mentioned axial pressure displacement adaptive system, comprising the following steps: S1: Install the axial pressure unit and the screwing assembly, and initialize the sensor; S2: Dynamically find the unloading point, control the axial pressure unit to start slowly and linearly increasing the pressure, and at the same time control the screwing assembly to maintain a constant output trial torque; S3: Judgment and Stop: Real-time monitoring of the angular displacement or rotation speed of the screwing assembly. Once the threaded ring is detected to start rotating, the system determines that the current moment is the critical unloading point and immediately stops the pressure increase action of the axial pressure unit. S4: Safely unscrew out, maintain the current axial pressure or reduce the pressure to the holding threshold, and drive the threaded ring to continue unscrewing; S5: Full release. When the threaded ring is detected to have turned out to the set number of turns or the set axial distance, it is determined that the elastic preload inside the valve has been fully released, and the axial pressure unit is controlled to completely remove the pressure.

[0013] Preferably, in step S2, the test torque is set to be less than 40% of the rated breaking torque of the threaded ring to ensure that the test turning will not damage the thread profile when the ring is not unloaded.

[0014] As a preferred embodiment, the disassembly and assembly method of the main steam valve adjusting valve threaded ring disassembly and assembly system with adaptive axial pressure displacement also includes a closed-loop control step for assembly preload: during the threaded ring screwing-in assembly stage, an axial load simulating working conditions is applied using an axial pressure unit, while the screwing-in torque is recorded; based on the real-time measured pressure-torque data, the actual friction coefficient of the threaded pair is calculated, and the final assembly preload torque value is corrected accordingly.

[0015] Preferably, in the dynamic unloading point search process of step S2, a control logic combining gradient pressurization and pulse probing is adopted. The central controller divides the pressurization process of the axial pressurization unit into several pressure steps. During the holding phase of each pressure step, the central controller instructs the screwing assembly to output a short-term pulse probing torque and monitors whether the threaded ring produces a small angular displacement. If no angular displacement occurs, the system proceeds to the next pressure step. If angular displacement occurs, the pressurization is stopped immediately, and the current pressure step value is recorded as the optimal unloading pressure value. The system maintains this optimal unloading pressure value throughout the initial stage of the threaded ring unscrewing, thereby achieving dynamic balance of the frictional force of the threaded pair.

[0016] According to the purpose of this invention, the above solution has the following technical effects: This axial pressure displacement adaptive main steam valve regulating valve threaded ring disassembly and assembly system uses a critical unloading judgment logic. Utilizing a step-like decrease in rotational resistance torque as a feedback signal, it accurately captures the moment the threaded ring disengages from its elastic compression state. Once this signal is detected, the central controller immediately commands a halt to pressurization, ensuring that the pressure applied by the axial pressure unit is maintained at only the minimum necessary value to loosen the threaded ring. This fundamentally eliminates equipment overload damage caused by continuous, blind pressurization, achieving adaptive safety protection for the main steam valve and regulating valve components. Furthermore, by real-time monitoring of the coupling relationship between rotational resistance torque and axial pressure, the system ensures that the tightening assembly rotates effectively only when the threaded ring is in a low-load or zero-load floating state. This avoids thread seizing, scoring, or excessive wear caused by forced tightening under insufficient axial pressure, significantly extending the service life of the threaded ring and valve body threads and reducing maintenance costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a main steam valve adjusting valve threaded ring disassembly and assembly system with adaptive axial pressure displacement according to an embodiment of the present invention.

[0018] Figure 2 yes Figure 1 A schematic diagram of the internal structure.

[0019] Figure 3 This is a reference diagram showing the usage state of a main steam valve adjusting valve threaded ring disassembly and assembly system with adaptive axial pressure displacement in an embodiment of the present invention during the disassembly of the threaded ring.

[0020] Figure 4 This is a reference diagram showing the usage state of the main steam valve adjusting valve threaded ring disassembly and assembly system with adaptive axial pressure displacement in an embodiment of the present invention when installing the threaded ring.

[0021] Figure 5 This is a flowchart of a disassembly and assembly method for a main steam valve adjusting valve threaded ring disassembly and assembly system using the above-mentioned axial pressure displacement adaptive system, according to an embodiment of the present invention.

[0022] Reference numerals: 1. Equipment housing; 2. Tightening assembly; 3. Axial pressure unit; 4. Valve cover; 5. Threaded ring; 6. U-ring; 7. Valve stem; 21. Pipe thread wrench; 22. Telescopic component; 23. Mounting bracket; 31. Bracket; 32. Sleeve; 33. Power component; 34. Stud; 211. Wrench body; 212. Extension arm. Detailed Implementation

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] Currently, the disassembly and assembly of the main steam valve and control valve threaded rings in ultra-supercritical units generally adopts the traditional hammer impact method. This method has significant drawbacks in practical applications. On the one hand, because the valves are in a high-temperature and high-pressure environment for a long time, the threaded rings and valve bodies are prone to metal creep or oxidation adhesion. Under such circumstances, using violent impact disassembly will cause uneven stress on the thread profile due to the instantaneous impact load, which can easily cause damage to the thread surface, burrs, or even instantaneous seizing. This often forces maintenance personnel to use destructive cutting methods, which seriously prolongs the construction period and increases maintenance costs.

[0025] On the other hand, the impact method makes it difficult to precisely control the torque applied to the threaded ring during assembly, and operators have difficulty quantifying the preload. This can easily lead to insufficient assembly force, resulting in the sealing pressure failing to meet the standard. After the unit is put into operation, areas with insufficient preload are prone to high-pressure steam leakage, which not only reduces the unit's thermal efficiency but also poses a significant safety hazard to on-site equipment and personnel.

[0026] In addition, in the current operation, due to the lack of real-time perception of the actual friction state of the threaded pair, operators often blindly set high pressure to press the valve cover all the way down. This open-loop control method is very easy to cause plastic deformation or overload damage to the precision components inside the valve due to excessive pressure. Conversely, if the pressure is insufficient, the axial friction force of the threaded pair cannot be completely eliminated, resulting in forced tightening.

[0027] like Figure 1 and Figure 2 As shown, an axial pressure displacement adaptive main steam valve adjusting thread ring removal and installation system includes a screwing assembly 2 and an axial pressure application unit 3. The screwing assembly 2 includes a pipe thread wrench 21, a telescopic component 22, and a mounting bracket 23 for mounting on the equipment housing 1. The fixed end of the telescopic component 22 is connected to the mounting bracket 23, and the telescopic end of the telescopic component 22 is connected to the pipe thread wrench 21.

[0028] like Figure 2 As shown, the axial pressure application unit 3 includes a bracket 31, a sleeve 32, and a power unit 33. The bracket 31 is mounted on the equipment housing 1. The sleeve 32 is coaxially arranged with the valve stem 7 of the equipment. The end of the sleeve 32 is provided with a pressure-bearing end face for contacting the valve cover 4. The power unit 33 is arranged between the sleeve 32 and the bracket 31, and is used to apply axial pressure to the valve cover 4 through the sleeve 32.

[0029] The screwing assembly 2 is configured such that after the axial pressure unit 3 applies axial pressure to the valve cover 4, it engages with the end of the threaded ring 5 through the pipe thread wrench 21, and the telescopic component 22 drives the pipe thread wrench 21 to screw the threaded ring 5.

[0030] like Figure 2As shown, the bracket 31 has a beam structure and spans across the opening of the equipment housing 1. To ensure the stability of the connection, both ends of the bracket 31 are fixed to the flange surface on the top of the equipment housing 1 by studs 34 and matching nuts.

[0031] The sleeve 32 is coaxially fitted around the valve stem 7 of the equipment, and the inner diameter of the sleeve 32 is larger than the outer diameter of the valve stem 7 to avoid interference. The bottom end of the sleeve 32 is provided with a flat pressure-bearing end face for direct contact and pressure against the valve cover 4 located below the threaded ring 5.

[0032] The power unit 33 preferably consists of at least two hydraulic jacks symmetrically arranged on the bracket 31, with their output ends abutting the top of the sleeve 32. When the power unit 33 operates, it drives the sleeve 32 to move axially downward, thereby applying axial pressure to the valve cover 4.

[0033] like Figure 2 and Figure 3 As shown, the mounting bracket 23 is fixed to the flange surface of the equipment housing 1 by bolt assembly, and the mounting bracket 23 is provided with a trunnion seat.

[0034] The telescopic component 22 is preferably a hydraulic cylinder. The cylinder body end of the hydraulic cylinder is hinged to the trunnion seat of the mounting bracket 23 by a pin, so that the hydraulic cylinder can swing at a certain angle in the horizontal plane.

[0035] The pipe thread wrench 21 includes an annular wrench body 211 and an extension arm 212 extending outward from the body. The diameter of the central opening of the wrench body 211 is larger than the outer diameter of the sleeve 32, allowing the pipe thread wrench 21 to fit over the sleeve 32 and engage with a groove or drive hole on the threaded ring 5 below. The piston rod end of the telescopic component 22 is hinged to the extension arm 212 via a pin.

[0036] like Figure 3 As shown, when disassembling the threaded ring 5, the axial pressure unit 3 is installed first. The power unit 33 is started, and the valve cover 4 is pressed down through the sleeve 32. As the valve cover 4 is pressed down, the U-shaped ring is compressed, which releases the spring force or structural tension that was originally pressed tightly on the lower end face of the threaded ring 5. The threaded pair between the threaded ring 5 and the equipment housing 1 is instantly unloaded, and the frictional resistance is greatly reduced.

[0037] At this time, as Figure 3 As shown, the pressure of the axial pressure unit 3 is maintained, and the telescopic component 22 is in a retracted or extended state, ensuring that its thrust direction can generate a counterclockwise (or the designed loosening direction) torque. Controlling the extension and retraction of the telescopic component 22 pushes the extension arm 212 of the pipe thread wrench 21, causing the threaded ring 5 to be easily loosened. Since the threaded ring 5 is unloaded, this process does not require impact, avoiding the risk of seizing.

[0038] like Figure 4As shown, when assembling the threaded ring 5, the angle of action of the telescopic component 22 relative to the pipe thread wrench 21 can be changed by changing the mounting position of the mounting bracket 23 on the flange surface of the equipment housing 1, for example, by installing it into the threaded hole on the other side symmetrical about the center, or by adjusting the angle.

[0039] like Figure 4 As shown, at this time, the thrust of the telescopic component 22 will drive the pipe thread wrench 21 to generate a clockwise torque (or the tightening direction specified in the design), screwing the threaded ring 5 into place. In the final tightening stage, a certain axial force can be applied in conjunction with the axial pressure unit 3 or the oil pressure value of the telescopic component 22 can be directly controlled to achieve quantitative control of the pre-tightening torque of the threaded ring 5, ensuring that the seal meets the standards.

[0040] The axial pressure displacement adaptive main steam valve adjusting threaded ring 5 disassembly and assembly system proposed in this embodiment of the invention also includes a pressure adaptive control system configured to adjust the output pressure of the axial pressure unit 3 in real time according to the screwing state of the threaded ring 5. The system includes a pressure monitoring module for real-time monitoring of the actual axial pressure value applied to the valve cover 4 by the axial pressure unit 3, a torque monitoring module for real-time monitoring of the rotational resistance torque when the screwing assembly 2 drives the threaded ring 5, and a central controller. The central controller is communicatively connected to the pressure monitoring module, the torque monitoring module, and the power component 33 of the axial pressure unit 3.

[0041] The central controller is equipped with critical unloading judgment logic: during the disassembly process, the central controller controls the axial pressure unit 3 to gradually apply pressure while monitoring the rotational resistance torque; when the rotational resistance torque is detected to have a step-down characteristic, it is determined that the threaded ring 5 has been released from the clamping state, and the central controller immediately instructs the axial pressure unit 3 to stop pressurizing or switch to low pressure holding mode.

[0042] Specifically, a pressure monitoring module is connected in series in the hydraulic circuit of the axial pressure unit 3 to provide real-time feedback on the actual axial pressure applied to the valve cover 4; a torque monitoring module is integrated in the screwing assembly 2, which can be directly measured by a dynamic torque sensor connected in series with the drive chain, or indirectly calculated by reading the current value of the servo motor to convert the rotational resistance torque. In addition, the system is also equipped with a displacement sensor to monitor the compression of the valve cover 4 and an angle sensor to monitor the rotation state of the threaded ring 5.

[0043] The central controller receives signals from all the aforementioned sensors and, based on the built-in PID algorithm and logic model, coordinates the pressure output of the power unit 33 and the movement of the telescopic component 22.

[0044] Based on the above hardware architecture, the torque-pressure coupling feedback control logic preset in the central controller is designed to resolve the contradiction between overpressure damaging the valve body and underpressure causing the threads to seize.

[0045] In actual operation, the central controller does not perform simple linear pressurization, but instead runs an algorithm of gradient pressurization and pulse probing. The specific process is as follows: The central controller divides the target range of axial pressure into several pressure steps, and controls the axial pressurization unit 3 to apply pressure step by step. During the holding phase of each pressure step, the controller instructs the screwing assembly 2 to output a short-duration pulse probing torque. The magnitude of this torque is strictly limited within the safe threshold of the rated breaking torque of the threaded ring 5. For example, the probing torque is set to be less than 40% of the rated breaking torque of the threaded ring 5.

[0046] Meanwhile, the central controller monitors the angular displacement response of the threaded ring 5 in real time. If no angular displacement occurs in the threaded ring 5 after applying the test torque, it indicates that the threaded ring 5 is still in a compressed state, and the system automatically enters the next pressure step. Once a small irreversible angular displacement is detected in the threaded ring 5, or a step drop in the rotational resistance torque is detected, the system immediately determines that the critical unloading point has been reached. At this time, the central controller triggers an interrupt command, stops pressurization, and locks the current pressure as the optimal unloading pressure, maintaining this pressure throughout the subsequent unscrewing process, thereby achieving minimal necessary control over the force on the equipment.

[0047] Based on the above system and logic, embodiments of the present invention provide a standardized disassembly operation method, including the following steps: S1: Install the axial pressure unit 3 and the screwing assembly 2, and initialize the sensor; S2: Dynamically find the unloading point and control the axial pressure unit 3 to start slowly and linearly increasing the pressure. At the same time, control the screwing assembly 2 to maintain a constant output trial torque. S3: Judgment and Stop: Real-time monitoring of the angular displacement or rotation speed of the screwing assembly 2. Once the threaded ring 5 is detected to start rotating, the system determines that the current moment is the critical unloading point and immediately stops the pressure increase action of the axial pressure unit 3. S4: Safely unscrew out, maintain the current axial pressure or reduce the pressure to the holding threshold, drive the threaded ring 5 to continue unscrewing; S5: Full release. When the threaded ring 5 is detected to have turned out to the set number of turns or the set axial distance, it is determined that the elastic preload inside the valve has been fully released, and the axial pressure unit 3 is controlled to completely remove the pressure.

[0048] like Figure 5As shown, the system is first installed and initialized, with all components in place and the sensors calibrated. Then, it enters the dynamic unloading point search phase, automatically performing gradient pressurization and pulse probing. Once the critical point of loosening of the threaded ring 5 is detected, it automatically switches to constant pressure holding mode. Next, a safe unscrewing step is performed. While maintaining the optimal unloading pressure, the screwing assembly 2 drives the threaded ring 5 to continuously unscrew. If an abnormal increase in resistance torque is detected during this process, the system will automatically pause and alarm to prevent thread damage. Finally, when the threaded ring 5 has unscrewed to the set number of turns or axial distance, and it is determined that the internal elastic preload of the valve has been completely transferred or released, the axial pressure unit 3 is controlled to slowly depressurize until it reaches zero, completing the disassembly operation.

[0049] Furthermore, the system also has significant technical advantages during the assembly stage, enabling closed-loop control of the preload. When the threaded ring 5 is screwed into the assembly, the system first applies a reference axial load simulating actual working conditions using the axial pressure unit 3. At this time, the screwing assembly 2 performs a small-angle trial screwing, and the controller simultaneously records the pressure and torque data.

[0050] Based on these measured data, the controller uses physical formulas to calculate the actual friction coefficient of the threaded pair. This coefficient accurately reflects the current lubrication condition and surface roughness. Subsequently, the controller automatically corrects the final assembly preload torque value based on the measured friction coefficient, eliminating preload deviations caused by friction coefficient fluctuations and ensuring the sealing performance and safety of the main steam valve and regulating valve under high temperature and high pressure conditions.

[0051] The present invention proposes an axial pressure displacement adaptive main steam valve adjusting valve threaded ring 5 disassembly and assembly system, which constructs a closed-loop pressure adaptive control system including pressure monitoring, torque monitoring, and a central controller. This system transforms the complex mechanical judgment process into automated control logic. The operation no longer relies on the operator's feel or experience, but is based on objective sensor data for real-time adjustment. This not only lowers the operational threshold and labor intensity but also ensures the consistency of work quality across different batches and personnel, significantly improving the efficiency and safety of on-site maintenance of ultra-supercritical thermal power units.

[0052] This invention is not limited to the specific technical solutions described in the above embodiments. Besides the above embodiments, this invention may have other implementation methods. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A kind of axial pressure displacement self-adapting main steam valve adjusting screw ring dismounting system, it is characterized by, Includes a screwing assembly, an axial pressure application unit, and a pressure adaptive control system; The screwing assembly is used to drive the threaded ring to rotate; The axial pressure unit is configured to apply axial pressure to the valve cover using a power component through a sleeve arranged coaxially with the valve stem. The pressure adaptive control system is configured to adjust the output pressure of the axial pressure unit in real time according to the screwing state of the threaded ring. It includes a pressure monitoring module for real-time monitoring of the actual axial pressure value applied to the valve cover by the axial pressure unit, a torque monitoring module for real-time monitoring of the rotational resistance torque when the screwing assembly drives the threaded ring, and a central controller. The central controller is communicatively connected to the pressure monitoring module, the torque monitoring module and the power component of the axial pressure unit. The central controller is equipped with critical unloading judgment logic: during the disassembly process, the central controller controls the axial pressure unit to gradually apply pressure while monitoring the rotational resistance torque; when the rotational resistance torque is detected to have a step-down characteristic, it is determined that the threaded ring has been released from the clamping state, and the central controller immediately instructs the axial pressure unit to stop pressurizing or switch to low-pressure holding mode.

2. The axial pressure displacement adaptive main steam valve adjusting threaded ring disassembly and assembly system according to claim 1, characterized in that, The pressure regulation logic of the central controller includes: During the trial phase, the axial pressure unit is controlled to increase pressure in a stepped manner with a preset pressure step size; Coupled detection, at each pressure step, controls the screwing assembly to output a trial torque with a set threshold; Adaptive locking: If the trial torque fails to drive the threaded ring to rotate, proceed to the next pressure step; if the threaded ring rotates and the torque value is lower than the set threshold, mark the current axial pressure value as the effective unloading pressure and lock the output of the axial pressure unit so that it will not increase the pressure during subsequent unscrewing.

3. The axial pressure displacement adaptive main steam valve adjusting valve threaded ring disassembly and assembly system according to claim 1, characterized in that, The turning assembly includes a hydraulic cylinder or a servo electric cylinder as the drive source. The torque monitoring module is a pressure sensor integrated in the hydraulic circuit of the drive source, or a dynamic torque sensor connected in series on the drive transmission chain. The central controller obtains the rotational resistance torque by calculating the pressure change of the drive source or by directly reading sensor values.

4. The axial pressure displacement adaptive main steam valve adjusting valve threaded ring disassembly and assembly system according to claim 1, characterized in that, The tightening assembly includes a pipe thread wrench, a telescopic component, and a mounting bracket for mounting on the equipment housing. The fixed end of the telescopic component is connected to the mounting bracket, and the telescopic end of the telescopic component is connected to the pipe thread wrench.

5. The axial pressure displacement adaptive main steam valve adjusting threaded ring disassembly and assembly system according to claim 1, characterized in that, The axial pressure unit includes a bracket, a sleeve, and a power component. The bracket is mounted on the equipment housing. The sleeve is coaxially arranged with the valve stem of the equipment. The end of the sleeve is provided with a pressure-bearing end face for contacting the valve cover. The power component is arranged between the sleeve and the bracket and is used to apply axial pressure to the valve cover through the sleeve.

6. The axial pressure displacement adaptive main steam valve adjusting valve threaded ring disassembly and assembly system according to claim 4, characterized in that, The pipe thread wrench includes a wrench body and an extension arm extending outward from the wrench body, and the telescopic end of the telescopic component is connected to the extension arm.

7. A method for disassembling and assembling the main steam valve adjusting threaded ring disassembly and assembly system using the axial pressure displacement adaptive system described in any one of claims 1-6, characterized in that, include: S1: Install the axial pressure unit and the screwing assembly, and initialize the sensor; S2: Dynamically find the unloading point, control the axial pressure unit to start slowly and linearly increasing the pressure, and at the same time control the screwing assembly to maintain a constant output trial torque; S3: Judgment and Stop: Real-time monitoring of the angular displacement or rotation speed of the screwing assembly. Once the threaded ring is detected to start rotating, the system determines that the current moment is the critical unloading point and immediately stops the pressure increase action of the axial pressure unit. S4: Safely unscrew out, maintain the current axial pressure or reduce the pressure to the holding threshold, and drive the threaded ring to continue unscrewing; S5: Full release. When the threaded ring is detected to have turned out to the set number of turns or the set axial distance, it is determined that the elastic preload inside the valve has been fully released, and the axial pressure unit is controlled to completely remove the pressure.

8. The disassembly and assembly method of the axial pressure displacement adaptive main steam valve adjusting valve threaded ring disassembly and assembly system according to claim 7, characterized in that, In step S2, the test torque is set to be less than 40% of the rated breaking torque of the threaded ring to ensure that the test turning will not damage the thread profile when the ring is not unloaded.

9. The disassembly and assembly method of the axial pressure displacement adaptive main steam valve adjusting valve threaded ring disassembly and assembly system according to claim 7, characterized in that, It also includes the assembly preload closed-loop control step: During the threaded ring screwing-in assembly stage, an axial load simulating the working condition is applied using an axial pressure unit, while the screwing-in torque is recorded. Based on the real-time measured pressure-torque data, the actual friction coefficient of the threaded pair is calculated, and the final assembly preload torque value is corrected accordingly.

10. The disassembly and assembly method of the axial pressure displacement adaptive main steam valve adjusting valve threaded ring disassembly and assembly system according to claim 7, characterized in that, In the dynamic unloading point search process described in step S2, a control logic combining gradient pressurization and pulse probing is adopted. The central controller divides the pressurization process of the axial pressure unit into several pressure steps. During the holding phase of each pressure step, the central controller instructs the screwing assembly to output a short-term pulse probe torque and monitors whether the threaded ring produces a small angular displacement. If no angular displacement occurs, proceed to the next pressure step; If angular displacement occurs, pressurization is stopped immediately, and the current pressure step value is recorded as the optimal unloading pressure value. The system maintains this optimal unloading pressure value throughout the initial stage of the threaded ring unscrewing, thereby achieving dynamic balance of the frictional force of the threaded pair.

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