Large-drift-diameter high-pressure hydraulic safety valve and detection method thereof

Abstract

The invention relates to the technical field of hydraulic safety valves, and discloses a large-drift-diameter high-pressure hydraulic safety valve and a detection method thereof.The detection method comprises the steps that hydraulic pressure signals and displacement signals are collected, and a standard detection data set is generated; identifying a pressure loading stage and a pressure unloading stage, and mapping the pressure loading stage and the pressure unloading stage into a valve opening phase and a valve closing phase to obtain a valve movement speed curve and a movement acceleration curve; identifying a speed abrupt change point and an acceleration zero crossing point in the movement process; mapping the pressure-displacement data of the valve opening phase and the valve closing phase to the same coordinate system, constructing a pressure-displacement hysteresis loop, and determining a surrounding area and a displacement deviation value; and judging whether the valve has defects or not according to the speed abrupt change point, the acceleration zero crossing point, the surrounding area and the displacement deviation value. According to the invention, the method achieves the recognition of the abnormal motion, and achieves the classification and judgment of the internal leakage defect and the motion clamping stagnation defect.

Description

Technical Field

[0001] This invention relates to the field of hydraulic safety valve technology, and more specifically, to a large-diameter, high-pressure hydraulic safety valve and its testing method. Background Technology

[0002] Hydraulic safety valves are widely used in offshore high-yield oil wells and high-speed injection-production gas storage wells to quickly cut off fluid channels and ensure production safety in abnormal situations. Existing conventional hydraulic safety valves are mostly small-sized with inner diameters of 2-9 / 16mm and 3-1 / 8mm. However, in special operating conditions such as offshore high-yield oil wells and high-speed injection-production gas storage wells, the small inner diameter of conventional safety valves cannot meet production requirements. Furthermore, large-diameter hydraulic safety valves require faster spring response and higher cylinder operating pressure. Therefore, large-diameter, high-pressure hydraulic safety valves are gradually being adopted.

[0003] However, with increased valve diameter and operating pressure, the valve plate mass, spring stiffness, and cylinder driving force increase during valve opening and closing, leading to more complex dynamic response characteristics and making the valve prone to problems such as delayed action, jamming, or decreased sealing performance. Existing testing methods mainly rely on static pressure tests or simple opening and closing tests, primarily determining whether the opening pressure has been reached or whether leakage exists. These methods lack analysis of the coupling relationship between pressure and displacement, making it difficult to accurately identify the start and end times of valve action and intermediate abnormal states, and also failing to provide a quantitative evaluation of sealing performance and operational flexibility.

[0004] Therefore, it is necessary to design a large-diameter, high-pressure hydraulic safety valve and its detection method to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes a large-diameter, high-pressure hydraulic safety valve and its detection method, aiming to solve the problems of difficulty in accurately identifying the start and end times of valve operation and intermediate abnormal states, and the inability to quantitatively evaluate sealing performance and operational flexibility.

[0006] In one aspect, the present invention proposes a testing method for a large-diameter, high-pressure hydraulic safety valve, comprising: The hydraulic pressure signal inside the cylinder is collected, and the displacement signal of the mechanical movement of the indicator rod is collected; the hydraulic pressure signal and the displacement signal are timestamped to generate synchronous time series data; and the synchronous time series data is preprocessed to generate a standard detection dataset. Based on the standard detection dataset, the pressure loading phase and the pressure unloading phase are identified; and the pressure loading phase is mapped to a valve opening phase, and the pressure unloading phase is mapped to a valve closing phase. The displacement signals during the valve opening and closing phases are differentiated to obtain the valve motion velocity curve and motion acceleration curve; the velocity change points and acceleration crossing zero points during the motion process are identified to determine the start time, end time, and intermediate jamming time of the valve action. The pressure-displacement data of the valve opening phase and the valve closing phase are mapped to the same coordinate system to construct a pressure-displacement hysteresis loop; and the area enclosed by the pressure-displacement hysteresis loop and the displacement deviation value of the opening curve and the closing curve at the same pressure point are determined. Based on the velocity mutation point, acceleration past zero point, enclosing area, and displacement deviation value, the valve's sealing performance index and operational flexibility index are generated, and the valve is determined to be defective.

[0007] Furthermore, when generating synchronized time series data, the following steps are included: Obtain the original timestamp sequences corresponding to the hydraulic pressure signal and the displacement signal; use the original timestamp sequence of the hydraulic pressure signal as the reference time axis to resample the original timestamp sequence of the displacement signal; fill in the data missing points in the resampling process by linear interpolation, and make the hydraulic pressure signal and the displacement signal have the same time interval and data length to form the synchronous time series data.

[0008] Furthermore, when generating the standard detection dataset, the following are included: The synchronized time series data is subjected to moving average filtering and normalization, and then arranged in chronological order to form the standard detection dataset.

[0009] Furthermore, when identifying the stress loading and stress unloading phases, the following are included: The slope of the hydraulic pressure signal in the standard test dataset as a function of time is determined; the time period with a slope greater than zero is identified as the pressure loading stage; the time period with a slope less than zero is identified as the pressure unloading stage; and the time period with a slope equal to zero is identified as the pressure holding stage.

[0010] Furthermore, when obtaining the valve's motion speed curve and motion acceleration curve, the following is included: The displacement signal is differentiated once to obtain an instantaneous velocity data sequence, which constitutes the valve motion velocity curve; the instantaneous velocity data sequence is differentiated twice to obtain an instantaneous acceleration data sequence, which constitutes the motion acceleration curve.

[0011] Furthermore, when identifying abrupt velocity changes and accelerations past zero during the motion process, and determining the start, end, and intermediate jamming moments of valve action, the following steps are taken: In the valve movement speed curve, determine the location where the speed value undergoes a step change and mark it as the speed change point; In the acceleration curve, the position where the acceleration value changes from positive to negative or from negative to positive is identified and marked as the acceleration point that passes zero. The time corresponding to the first velocity mutation point is determined as the start time, the time corresponding to the last velocity mutation point is determined as the end time, and the time when the velocity is lower than the average speed is determined as the intermediate jamming time.

[0012] Furthermore, when constructing the pressure-displacement hysteresis loop, the following steps are included: Establish a two-dimensional rectangular coordinate system with hydraulic pressure as the abscissa and indicator rod displacement as the ordinate; Connect the pressure-displacement data points within the valve opening phase in chronological order to form the opening trajectory line; Connect the pressure-displacement data points within the valve closing phase in chronological order to form a closing trajectory line; The opening trajectory line and the closing trajectory line are closed to form the pressure-displacement hysteresis loop.

[0013] Furthermore, determining the enclosing area of ​​the pressure-displacement hysteresis loop and the displacement deviation between the opening and closing curves at the same pressure point includes: The area of ​​the enclosed region between the opening trajectory line and the closing trajectory line is determined as the enclosed area; At the preset pressure sampling points, extract the ordinate values ​​corresponding to the opening trajectory line and the closing trajectory line, and determine the absolute value of the difference between the two as the displacement deviation value.

[0014] Furthermore, when generating the valve's sealing performance index and operational flexibility index, and determining whether the valve is defective, the following steps are taken: The sealing performance index is generated by weighting the enclosing area and displacement deviation value. The motion agility index is generated by statistical analysis based on the distribution density of the velocity abrupt change points and the number of accelerations passing zero points. The sealing performance index is compared with a preset sealing threshold. If the sealing performance index is greater than the sealing threshold, the valve is determined to have an internal leakage defect. The motion flexibility index is compared with a preset flexibility threshold. If the motion flexibility index is greater than the flexibility threshold, it is determined that the valve has a motion jamming defect.

[0015] On the other hand, this application also provides a large-diameter, high-pressure hydraulic safety valve, and a detection method for the above-mentioned large-diameter, high-pressure hydraulic safety valve, including a housing assembly and a drive assembly; The housing assembly, from top to bottom, includes a hydraulic cylinder, an actuator housing, a valve cover, a valve body, and a valve seat; the hydraulic cylinder, actuator housing, valve cover, valve body, and valve seat are all fixedly connected in sequence; the lower end of the hydraulic cylinder extends into the actuator housing, and the upper end of the valve cover extends into the actuator housing; the valve body and valve seat are fitted together to form a valve port; The drive assembly includes an indicator rod, a piston, a spring plate, a spring, a valve stem, and a valve plate. The top of the cylinder has a through hole that mates with the indicator rod, allowing the lower end of the indicator rod to extend into the cylinder. The lower end of the indicator rod is connected to the upper end of the piston. The lower end of the piston is connected to the upper end of the spring plate. The lower end of the spring plate has a through rod, and the upper end of the valve stem has a through hole. The through rod and the through hole connect to fix the lower end of the spring plate to the upper end of the valve stem. The spring plate and the valve stem are also circumferentially connected. A spring is provided, with its upper end fixed to the spring pressure plate and its lower end fixed to the upper end of the valve cover extending into the actuator housing. The valve cover has a sliding hole that mates with the valve stem, allowing the valve stem and valve cover to move and be fixed through a specific structure at the bottom of the valve stem. The valve plate also has a fixing groove that mates with a specific structure at the bottom of the valve stem, allowing the valve plate and valve stem to be fixedly connected through the cooperation of the specific structure and the fixing groove. The valve plate also has a flow hole that mates with the valve port.

[0016] Compared with existing technologies, the advantages of this invention are as follows: By aligning and synchronizing the hydraulic pressure signal and the indicator rod displacement signal with timestamps, unified time series data is constructed, enabling dynamic coupling analysis of the entire valve opening and closing process and improving detection accuracy. By differentiating the displacement signal to obtain velocity and acceleration curves, and identifying velocity abrupt change points and acceleration zero-crossing points, the start, end, and intermediate jamming moments of valve action can be accurately determined, achieving refined identification of abnormal actions. By mapping the pressure-displacement data of the opening and closing phases to the same coordinate system, a hysteresis loop is constructed, and the enclosing area and displacement deviation under the same pressure are calculated, transforming the sealing performance from a qualitative judgment to a quantifiable indicator, improving the objectivity of defect identification. A sealing performance index is constructed based on the hysteresis loop characteristics, and an action flexibility index is constructed based on velocity and acceleration characteristics, enabling the classification and judgment of internal leakage defects and action jamming defects. Designed to address the characteristics of large-diameter, high-pressure valves—high inertia, rapid response, and strong impact—this system can capture dynamic anomalies, solving the problem of traditional static testing's difficulty in detecting potential defects. It is suitable for special operating conditions such as high-yield offshore oil wells and high-speed injection and production in gas storage facilities. Through the coaxial arrangement and rigid connection structure of the shell and drive components, the displacement of the indicator rod and the movement of the valve stem are transmitted synchronously, ensuring that the detection data accurately reflects the internal motion state of the valve and improving the detection method. The safety valve has a larger flow channel orifice inner diameter, meeting the high-flow production operation requirements of special sites and conditions. The safety valve has a larger stroke displacement from fully closed to fully open, requiring a higher response speed from the large-sized spring. When the cylinder pressure is removed, the safety valve can quickly close within the customer-specified pipeline size and specifications. The cylinder pressure is higher than before; the maximum operating pressure of the cylinder in small-diameter safety valves is generally 4000 psi, while the maximum operating pressure of the cylinder in large-diameter high-pressure safety valves can reach 6000 psi. The large-diameter safety valve uses a T-block design for the valve plate and stem connection. Compared with the threaded connection of small-diameter safety valves, it can withstand greater loads during operation, has a smaller clearance, avoids loosening of the connection, and achieves rapid positioning and stable connection in the vertical direction. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A flowchart illustrating the testing method for a large-diameter, high-pressure hydraulic safety valve provided in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a large-diameter, high-pressure hydraulic safety valve provided in an embodiment of the present invention. Figure 1 ; Figure 3 A schematic diagram of the structure of a large-diameter, high-pressure hydraulic safety valve provided in an embodiment of the present invention. Figure 2 .

[0018] The components are: 1. Valve body; 2. Valve seat; 3. Valve plate; 4. Valve cover; 5. Valve stem; 6. Actuator housing; 7. Spring; 8. Spring pressure plate; 9. Piston; 10. Oil cylinder; 11. Indicator rod. Detailed Implementation

[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] In some embodiments of this application, see Figure 1 As shown, a testing method for large-diameter, high-pressure hydraulic safety valves is proposed, including: S100: Acquires hydraulic pressure signals from the cylinder and displacement signals from the mechanical movement of the indicator rod; timestamps the hydraulic pressure and displacement signals to generate synchronous time series data; and preprocesses the synchronous time series data to generate a standard test dataset. S200: Based on the standard test dataset, identify the pressure loading phase and the pressure unloading phase; and map the pressure loading phase to the valve opening phase and the pressure unloading phase to the valve closing phase; S300: Differentiate the displacement signals during the valve opening and closing phases to obtain the valve velocity curve and acceleration curve; identify the velocity change points and acceleration zero-crossing points during the movement process to determine the start time, end time, and intermediate jamming time of the valve action; S400: Map the pressure-displacement data of the valve opening phase and the valve closing phase to the same coordinate system to construct a pressure-displacement hysteresis loop; and determine the enclosing area of ​​the pressure-displacement hysteresis loop and the displacement deviation between the opening curve and the closing curve at the same pressure point. S500: Based on the velocity change point, acceleration passing zero point, enclosing area, and displacement deviation value, generate the valve's sealing performance index and actuation flexibility index, and determine whether the valve is defective.

[0021] Specifically, in step S100, a high-precision pressure sensor installed inside the cylinder acquires hydraulic pressure signals in real time, while a displacement sensor acquires the axial displacement signal of the indicator rod. During the acquisition process, the original timestamp sequences of both types of signals are recorded. Using the pressure signal time axis as a reference, the displacement signal is resampled to form a data sequence with equal time intervals for both types of signals under a unified time reference. Subsequently, the synchronized time series data is subjected to moving average filtering to eliminate high-frequency noise, and then normalized and standardized to form a standard detection dataset.

[0022] In step S200, the slope of the hydraulic pressure signal in the standard detection dataset is calculated. By judging the trend of pressure change over time, the interval with a slope greater than zero is identified as the pressure loading stage, and the interval with a slope less than zero is identified as the pressure unloading stage. Based on this, it is mapped to the valve opening phase and the valve closing phase respectively, so as to realize the automatic segmentation of the opening and closing process from the time dimension.

[0023] In step S300, a differential operation is performed on the displacement signals within the opening and closing phases to obtain an instantaneous velocity data sequence, constructing a valve motion velocity curve. A second differential operation is then performed on the velocity data to obtain an instantaneous acceleration data sequence, constructing a motion acceleration curve. Velocity abrupt change points are determined by analyzing the step change positions in the velocity curves, and acceleration zero-crossing points are determined by identifying positions in the acceleration curve where the velocity changes from positive to negative or vice versa. The time corresponding to the first velocity abrupt change point is defined as the start time of the action, and the time corresponding to the last velocity abrupt change point is defined as the end time of the action. Time periods during the motion where the velocity is significantly lower than the average motion velocity are identified as intermediate lag times.

[0024] In step S400, the pressure-displacement data within the opening and closing phases are mapped to a unified two-dimensional Cartesian coordinate system, with pressure as the abscissa and displacement as the ordinate, forming opening and closing trajectory lines respectively. These two trajectories are then closed to form a pressure-displacement hysteresis loop. The closed area of ​​this hysteresis loop is further calculated to characterize energy loss and sealing hysteresis characteristics. Simultaneously, the displacement values ​​corresponding to the opening and closing curves are extracted at preset pressure sampling points, and their absolute deviation is calculated to reflect the consistency of opening and closing.

[0025] In step S500, a weighted evaluation is performed based on the area enclosed by the hysteresis loop and the displacement deviation value to generate a sealing performance index; a motion flexibility index is generated based on the distribution density of velocity mutation points and the number of accelerations passing zero points through statistical analysis. These indices are then compared with preset thresholds. When the sealing performance index exceeds the sealing threshold, an internal leakage defect is identified; when the motion flexibility index exceeds the flexibility threshold, a motion jamming defect is identified, thus completing defect identification and classification.

[0026] Understandably, by synchronously acquiring and coupling the pressure and displacement signals, a pressure-displacement hysteresis loop is established, and a dual-index evaluation system is constructed by combining velocity and acceleration characteristics. This enables quantitative detection of the sealing performance and operational flexibility of large-diameter high-pressure hydraulic safety valves, accurately identifying the start and end times of the operation and intermediate jamming states, improving the accuracy of defect judgment, and enhancing the ability to identify dynamic anomalies under high-pressure large-diameter operating conditions.

[0027] In some embodiments of this application, generating synchronized time series data includes: Obtain the original timestamp sequences corresponding to the hydraulic pressure signal and displacement signal; use the original timestamp sequence of the hydraulic pressure signal as the reference time axis to resample the original timestamp sequence of the displacement signal; fill the data missing points in the resampling process through linear interpolation, and make the hydraulic pressure signal and displacement signal have the same time interval and data length to form synchronous time series data.

[0028] Specifically, the raw data sequences output by the hydraulic pressure sensor and displacement sensor are read from the data acquisition module, and their corresponding raw timestamp sequences are extracted. Due to differences in hardware structure, sampling frequency, start-up time, and internal clock accuracy between the two types of sensors, their sampling time points typically do not completely overlap, and the number of data points may differ. Direct data calculation can easily lead to phase misalignment between pressure and displacement, affecting feature recognition accuracy. Subsequently, the raw timestamp sequence of the hydraulic pressure signal is used as the reference time axis. Preferably, the pressure signal typically has high sampling stability and can accurately reflect the time boundaries of loading and unloading; therefore, using its time sequence as a unified time reference has good engineering adaptability. Then, based on this reference time axis, the displacement signal is resampled. That is, for each time node in the reference time axis, its corresponding interval is found in the raw displacement data, and the displacement value at that time node is calculated. During the resampling process, when the reference time node and the raw timestamp of the displacement signal do not completely overlap, a linear interpolation algorithm is used for data estimation. Specifically, the process involves selecting the two nearest known displacement sampling points before and after the target time point, linearly distributing the displacement difference according to the time difference ratio, and calculating the interpolated displacement value for that target time point. This linear interpolation method ensures the continuity and smoothness of the displacement signal in the time dimension, while avoiding the oscillation errors and increased computational complexity introduced by higher-order interpolation algorithms. After the above resampling and interpolation processing, the hydraulic pressure signal and displacement signal have the same time interval and data length on a unified time axis, forming a one-to-one corresponding data pair and constructing synchronous time series data. This synchronous time series data can accurately reflect the pressure and displacement states at the same moment.

[0029] Understandably, by establishing a unified time reference and using linear interpolation to complete the resampling process, the pressure signal and displacement signal are strictly time aligned, avoiding phase shifts and feature misjudgments caused by asynchronous sampling, thus improving the accuracy and stability of dynamic analysis.

[0030] In some embodiments of this application, generating a standard detection dataset includes: The synchronous time series data are subjected to moving average filtering and normalization, and then arranged in chronological order to form a standard detection dataset.

[0031] Specifically, after obtaining the synchronous time series data, the hydraulic pressure signal and displacement signal in the synchronous time series data are first subjected to moving average filtering. Preferably, a fixed-length moving time window is set, and the window length can be selected according to the sampling frequency and valve action cycle, for example, selecting the number of time points covering several sampling cycles as the window width. During the sliding process, the data within the window is calculated by arithmetic mean, and this average value is used to replace the original data at the center position of the window, thereby achieving smoothing of high-frequency noise and instantaneous spike interference. Through moving average filtering, the effects of sensor acquisition error, mechanical vibration interference, and electromagnetic noise can be effectively suppressed, while maintaining the overall trend without significant distortion. After completing the filtering process, the pressure signal and displacement signal are normalized respectively. The normalization method can adopt the extreme value normalization method, that is, according to the maximum and minimum values ​​of each signal in the current detection cycle, the original data is linearly mapped to a preset standard interval, such as the [0,1] interval; or the mean-variance standardization method is adopted to transform the data into a standard distribution form with a mean of zero and a standard deviation of one. Normalization eliminates the influence of differences in measurement range, operating conditions, or sensor calibration errors between different test batches, ensuring a uniform scale for all data types. Finally, the filtered and normalized pressure and displacement signals are rearranged in chronological order, maintaining a one-to-one correspondence with the reference time axis, forming a standardized test dataset with a unified structure and format. This dataset includes timestamps, standardized pressure values, and standardized displacement values.

[0032] Understandably, by applying moving average filtering and normalization to synchronous time series data, the impact of noise interference and abnormal fluctuations on the analysis results can be effectively reduced, improving data stability and comparability; at the same time, unifying the data scale enhances the stability and accuracy of feature extraction and evaluation calculations.

[0033] In some embodiments of this application, identifying the pressure loading phase and the pressure unloading phase includes: Determine the slope of the hydraulic pressure signal in the standard test dataset as a function of time; time periods with a slope greater than zero are identified as the pressure loading stage; time periods with a slope less than zero are identified as the pressure unloading stage; and time periods with a slope equal to zero are identified as the pressure holding stage.

[0034] Specifically, after obtaining the standard test dataset, the hydraulic pressure data sequence arranged in chronological order is first extracted. Then, the slope of the hydraulic pressure signal is calculated. Preferably, the differential method is used to calculate the pressure change rate between adjacent sampling points. That is, the pressure change rate per unit time is obtained by dividing the difference between the current pressure value and the previous pressure value by the corresponding time interval, which is used as the instantaneous slope value at that time point. With a high sampling frequency, the above differential operation can approximately reflect the continuous derivative characteristics of pressure changing with time. To improve recognition stability, a slope judgment threshold can be further set. When the slope is greater than a preset positive threshold, the time period is identified as the pressure loading stage, indicating that the hydraulic pressure inside the cylinder is rising, corresponding to the gradual opening of the valve; when the slope is less than a preset negative threshold, the time period is identified as the pressure unloading stage, indicating that the hydraulic pressure is falling, corresponding to the gradual closing of the valve; when the slope is between the preset positive and negative thresholds, i.e., approximately equal to zero, the time period is identified as the pressure holding stage, indicating that the system is in a stable or short-term transition state. After completing the above determination, the time points that continuously meet the same slope characteristics are merged to form several continuous time intervals, which are respectively marked as the pressure loading stage, pressure unloading stage, or pressure holding stage.

[0035] Understandably, by calculating and segmenting the slope of the hydraulic pressure signal, the automatic identification and precise division of the valve opening and closing process are achieved, avoiding subjective errors caused by manual judgment; it can effectively distinguish between loading, unloading and holding states, improving the accuracy and stability of stage identification.

[0036] In some embodiments of this application, obtaining the valve motion velocity curve and motion acceleration curve includes: Perform a first differentiation operation on the displacement signal to obtain an instantaneous velocity data sequence, which forms the valve motion velocity curve; perform a second differentiation operation on the instantaneous velocity data sequence to obtain an instantaneous acceleration data sequence, which forms the motion acceleration curve.

[0037] Specifically, after dividing the pressure phase, displacement signal data sequences corresponding to the valve opening and closing phases are extracted from the standard test dataset. The displacement signal is the real-time axial displacement of the indicator rod, directly reflecting the motion state of the valve stem and valve plate. Since the displacement signal is discrete-time sampled data, numerical differentiation is preferred for calculation. First, a differential operation is performed on the displacement signal to obtain the instantaneous velocity data sequence. Specifically, the difference method can be used to calculate the displacement change between adjacent sampling points divided by the corresponding time interval, i.e.: Instantaneous velocity = (Current displacement value - Previous displacement value) / Time interval. With a stable sampling frequency and a fixed time interval, the velocity value can be directly obtained by multiplying the difference between adjacent displacements by the sampling frequency coefficient. The velocity data obtained through the above calculations are arranged in chronological order to form the valve motion velocity curve. This velocity curve reflects the changes in the speed of movement during valve opening and closing. Subsequently, a second differential operation is performed on the instantaneous velocity data sequence, i.e., the velocity data is differentially processed again to obtain the instantaneous acceleration data sequence. The specific calculation method is: Instantaneous acceleration = (Current velocity value - Previous velocity value) / Time interval. The acceleration data obtained through the above calculations, arranged in chronological order, constitute the motion acceleration curve. This acceleration curve can reflect the force changes and dynamic impact characteristics during the valve's movement, especially at the instant of opening and closing and at the turning points of the movement, where the acceleration changes are more obvious.

[0038] Understandably, by performing first and second differential operations on the displacement signal to construct velocity and acceleration curves respectively, the dynamic characteristics of the valve opening and closing process are transformed from displacement changes to velocity and acceleration changes. This enables refined analysis of the speed of action and impact characteristics, and improves the ability to identify abnormal actions, jamming, and impact phenomena.

[0039] In some embodiments of this application, identifying abrupt velocity changes and accelerations passing zero during motion, and determining the start time, end time, and intermediate jamming time of valve action, includes: In the valve motion speed curve, identify the location where the speed value undergoes a step change and mark it as the speed change point; In the acceleration curve, identify the position where the acceleration value changes from positive to negative or from negative to positive, and mark it as the point where the acceleration passes zero. The moment corresponding to the first velocity change point is determined as the start moment, the moment corresponding to the last velocity change point is determined as the end moment, and the moment when the velocity is lower than the average speed is determined as the intermediate stagnation moment.

[0040] Specifically, after obtaining the valve's velocity and acceleration curves, the velocity curves are first analyzed for their change characteristics. Preferably, the difference between adjacent velocity sampling points is calculated to determine whether the velocity change exceeds a preset step change threshold. When the velocity change at a certain moment exceeds the preset threshold, a significant velocity step change is considered to exist at that location, and this time point is marked as a velocity abrupt change point. The threshold can be set according to the valve's rated velocity range and sampling accuracy to avoid minor fluctuations being misjudged as abrupt changes. Secondly, the acceleration curves are checked for sign changes. Specifically, the acceleration data sequence is traversed; when the acceleration value at a certain time point changes from positive to negative or from negative to positive, it indicates a change in acceleration direction at that moment, i.e., a turning point in the motion force state or motion trend. This time point is marked as an acceleration zero-crossing point. To avoid noise interference, a minimum zero-crossing amplitude condition can be set; that is, only when the absolute values ​​of acceleration before and after the zero-crossing are both greater than a preset threshold is it considered a valid zero-crossing point. After marking the velocity abrupt change points and acceleration zero-crossing points, a comprehensive analysis is performed based on the time sequence. The moment corresponding to the first velocity abrupt change is defined as the start time of valve action, typically the time when the valve transitions from a stationary state to a moving state. The moment corresponding to the last velocity abrupt change is defined as the end time of valve action, the time when the valve's movement ends and tends to stabilize. Simultaneously, within the movement interval between the start and end times, the average movement velocity is calculated and compared with the instantaneous velocity. When the instantaneous velocity remains consistently lower than the average movement velocity for a period exceeding a preset time threshold, this period is identified as an intermediate jamming moment or jamming interval. This jamming state typically reflects problems such as abnormal friction, structural interference, or spring response mismatch in the valve stem or valve plate during movement.

[0041] Understandably, by identifying the points of sudden speed change and acceleration past zero, the valve's start and end times can be accurately located, avoiding errors in human judgment; by identifying intermediate stuck moments, abnormal motion and friction faults can be detected.

[0042] In some embodiments of this application, constructing the pressure-displacement hysteresis loop includes: Establish a two-dimensional rectangular coordinate system with hydraulic pressure as the abscissa and indicator rod displacement as the ordinate; Connect the pressure-displacement data points within the valve opening phase in chronological order to form the opening trajectory line; Connect the pressure-displacement data points within the valve closing phase in chronological order to form the closing trajectory line; The opening and closing trajectory lines are closed to form a pressure-displacement hysteresis loop.

[0043] Specifically, after dividing the valve into opening and closing phases, the corresponding hydraulic pressure and displacement data for each phase are extracted. A two-dimensional Cartesian coordinate system is then established, with hydraulic pressure as the abscissa and indicator rod displacement as the ordinate. The abscissa represents the driving force input state, and the ordinate represents the response state of the valve actuator, thus establishing a drive-response coupling relationship. In the two-dimensional coordinate system, the pressure-displacement data points within the valve opening phase are connected sequentially in time to form the opening trajectory line. The opening trajectory line reflects the dynamic relationship of displacement change as the pressure gradually increases; its curve shape reflects the influence of factors such as spring compression characteristics, frictional resistance, and structural inertia on the motion process. Similarly, the pressure-displacement data points within the valve closing phase are connected sequentially in time to form the closing trajectory line. The closing trajectory line reflects the dynamic characteristics of displacement return as the pressure gradually decreases; its curve shape reflects the spring reset characteristics, sealing rebound characteristics, and possible internal leakage or hysteresis phenomena. Because the opening and closing processes are affected by factors such as structural friction, elastic hysteresis, and fluid damping, they usually do not completely overlap. Therefore, the opening trajectory and the closing trajectory form a closed or nearly closed annular region in the same coordinate system. Connecting the opening and closing trajectories end to end and closing them forms a pressure-displacement hysteresis loop. The shape, area, and degree of separation of this hysteresis loop can comprehensively reflect the energy loss, response hysteresis, and sealing performance differences of the valve during the opening and closing cycle.

[0044] Understandably, by establishing a pressure-displacement hysteresis loop, the driving force and displacement response during the valve opening and closing process are modeled in a unified manner, reflecting the hysteresis difference and energy loss during the opening and closing process, thus achieving a comprehensive quantitative analysis of sealing performance and dynamic characteristics.

[0045] In some embodiments of this application, determining the enclosing area of ​​the pressure-displacement hysteresis loop and the displacement deviation between the opening and closing curves at the same pressure point includes: Determine the area of ​​the enclosed region between the open trajectory line and the closed trajectory line, and use it as the bounding area; At the preset pressure sampling points, extract the ordinate values ​​corresponding to the opening trajectory line and the closing trajectory line, and determine the absolute value of the difference between the two as the displacement deviation value.

[0046] Specifically, after constructing the pressure-displacement hysteresis loop, the area of ​​the closed region formed between the opening and closing trajectory lines is first calculated. Preferably, a numerical integration method can be used. For example, the pressure axis is discretized at equal intervals, and the displacement difference between the opening and closing curves within the same pressure range is integrated. The area of ​​each discrete segment is then summed to obtain the area of ​​the overall closed region. Alternatively, a polygon area calculation method can be used, where the opening and closing trajectory points are sequentially combined to form a closed polygon, and its area is calculated using coordinate methods. The area value is the enclosed area of ​​the hysteresis loop, and its physical meaning lies in characterizing the energy loss and response lag caused by factors such as friction, seal deformation, and fluid damping during the opening and closing cycle. Secondly, to further characterize the response differences under the same pressure conditions during the opening and closing processes, displacement deviation is calculated at preset pressure sampling points. Specifically, several equally spaced or key pressure nodes are selected as sampling points on the pressure axis. The ordinates of the opening and closing trajectory lines corresponding to the pressure value are obtained through interpolation, which represent the corresponding displacement values. Then, the absolute value of the difference between the two is calculated to obtain the displacement deviation value at that pressure point. The displacement deviation values ​​of multiple pressure sampling points can be statistically processed, such as taking the average, maximum, or weighted average, to form the overall displacement deviation characteristic parameter.

[0047] Understandably, by calculating the area and extracting the displacement deviation from the pressure-displacement hysteresis loop, the originally abstract hysteresis phenomenon is transformed into a quantifiable numerical indicator, enabling an accurate assessment of the degree of sealing hysteresis and the consistency of opening and closing, thereby improving the objectivity and comparability of sealing performance judgment.

[0048] In some embodiments of this application, when generating the sealing performance index and operational flexibility index of the valve, and determining whether the valve is defective, the process includes: A sealing performance index is generated by weighting the enclosing area and displacement deviation values. A motion flexibility index is generated by statistical analysis based on the distribution density of velocity abrupt change points and the number of accelerations passing zero points. The sealing performance index is compared with the preset sealing threshold. If the sealing performance index is greater than the sealing threshold, the valve is determined to have an internal leakage defect. The agility index is compared with a preset agility threshold. If the agility index is greater than the agility threshold, the valve is determined to have an agility jamming defect.

[0049] Specifically, when generating the sealing performance index, the enclosing area and displacement deviation are used as important evaluation factors reflecting sealing performance. First, the enclosing area and displacement deviation are standardized to ensure comparability of data between different test batches or valves of different specifications. Then, the enclosing area and displacement deviation are weighted according to preset weights to form a comprehensive sealing performance index. The weighted evaluation can be based on actual operating conditions, design requirements, or historical test data, ensuring that the reflection of the overall hysteresis by the enclosing area and the reflection of the displacement deviation on the degree of difference under the same pressure are reasonably reflected in the comprehensive index. When the enclosing area of ​​the hysteresis loop increases or the displacement deviation at the same pressure point increases, the sealing performance index increases accordingly, reflecting potential wear, deformation, or increased clearance between valve sealing pairs, thus indicating the risk of internal leakage. When generating the motion flexibility index, the distribution density of velocity abrupt change points and the number of accelerations crossing zero points are used as evaluation criteria for motion smoothness. By statistically analyzing the frequency of velocity abrupt change points per unit time and the number of acceleration sign changes throughout the entire opening and closing cycle, the impact, oscillation, and discontinuous changes during valve movement are quantitatively analyzed. The statistical results are then processed to generate an operational flexibility index. When the distribution of velocity abrupt change points is dense or the number of accelerations passing zero points increases abnormally, it indicates instability in the valve's movement, possibly caused by abnormal frictional resistance, spring performance degradation, guide component misalignment, or structural jamming. In this case, the operational flexibility index increases accordingly. After generating the two indices, the sealing performance index is compared with a preset sealing threshold. If the sealing performance index is greater than the sealing threshold, the valve is considered to have an internal leakage defect; if it is not greater than the threshold, the sealing performance is considered to meet the requirements. Simultaneously, the operational flexibility index is compared with a preset flexibility threshold. If the operational flexibility index is greater than the flexibility threshold, the valve is considered to have an operational jamming defect; if it is not greater than the threshold, the valve's operational performance is considered normal. By independently evaluating and determining the thresholds for sealing performance and operational performance, different types of defects can be classified and identified.

[0050] Understandably, by weighting and statistically analyzing the hysteresis loop characteristic parameters and kinematic characteristic parameters, sealing performance index and action flexibility index are constructed, enabling quantitative and definable identification of internal leakage defects and action jamming defects. This improves the objectivity and reliability of the detection process and is conducive to enhancing the quality control level and operational safety of large-diameter high-pressure hydraulic safety valves.

[0051] Based on another preferred embodiment described above, see [link to preferred embodiment]. Figure 2-3 As shown, this embodiment provides a large-diameter, high-pressure hydraulic safety valve, and a detection method for the aforementioned large-diameter, high-pressure hydraulic safety valve, including a housing assembly and a drive assembly; The housing assembly, from top to bottom, includes a hydraulic cylinder 10, an actuator housing 6, a valve cover 4, a valve body 1, and a valve seat 2; the hydraulic cylinder 10, actuator housing 6, valve cover 4, valve body 1, and valve seat 2 are all fixedly connected in sequence; the lower part of the hydraulic cylinder 10 extends into the actuator housing 6, and the upper part of the valve cover 4 extends into the actuator housing 6; the valve body 1 and valve seat 2 are connected to form a valve port; The drive assembly includes an indicator rod 11, a piston 9, a spring plate 8, a spring 7, a valve stem 5, and a valve plate 3. The top of the cylinder 10 has a through hole that mates with the indicator rod 11, allowing the lower end of the indicator rod 11 to extend into the cylinder 10. The lower end of the indicator rod 11 is connected to the upper end of the piston 9. The lower end of the piston 9 is connected to the upper end of the spring plate 8. The lower end of the spring plate 8 has a through rod, and the upper end of the valve stem 5 has a through hole. The through rod and the through hole connect to fix the lower end of the spring plate 8 to the upper end of the valve stem 5. The spring plate 8 and the valve... A spring 7 is also provided on the outer periphery of the rod 5. The upper end of the spring 7 is fixed on the spring pressure plate 8, and the lower end of the spring 7 is fixed on the upper end of the valve cover 4 that extends into the actuator housing 6. The valve cover 4 is provided with a sliding hole that cooperates with the valve rod 5. Through a specific structure at the bottom of the valve rod 5, the valve rod 5 and the valve cover 4 can be moved and fixed. The valve plate 3 is also provided with a fixing groove that cooperates with a specific structure at the bottom of the valve rod 5. Through the cooperation of the specific structure and the fixing groove, the valve plate 3 and the valve rod 5 can be fixedly connected. The valve plate 3 is also provided with a flow hole that cooperates with the valve port.

[0052] Specifically, when the large-diameter high-pressure hydraulic safety valve is in operation, the external hydraulic system inputs hydraulic oil into the cylinder 10. The hydraulic pressure acts on the upper surface of the piston 9, causing the piston 9 to move axially within the cylinder 10, and simultaneously driving the indicator rod 11 connected to it to move synchronously, thereby achieving a visual indication of the valve's opening status. When the piston 9 moves downward, it pushes the spring plate 8 to compress the spring 7 located on its outer periphery, and the spring 7 generates an elastic restoring force. At the same time, the spring plate 8 is connected to the through hole at the upper end of the valve stem 5 through the through rod at its lower end, causing the valve stem 5 to move downward synchronously in the axial direction. The valve stem 5 slides in the sliding hole of the valve cover 4, and its specific structure at the bottom cooperates with the fixing groove on the valve plate 3, thereby reliably transmitting the axial movement to the valve plate 3, causing the valve plate 3 to displace relative to the valve seat 2, and changing the opening degree of the valve port. When the hydraulic pressure reaches the set value, the valve plate 3 fully opens against the preload of the spring 7, allowing the medium to be released through the valve port and the flow holes on the valve plate 3, thus releasing excessive pressure. When the pressure decreases or the hydraulic pressure is unloaded, the pressure inside the cylinder 10 decreases, and the spring 7, under the action of the restoring force, pushes the spring plate 8, valve stem 5, and valve plate 3 to move in the opposite direction, causing the valve plate 3 to press the valve seat 2 again, closing the valve port and achieving a seal. The automatic opening and resetting of the valve is achieved through the balance between hydraulic pressure and spring force.

[0053] In summary, by aligning and synchronizing the hydraulic pressure signal and the indicator rod displacement signal with timestamps, a unified time series data was constructed, enabling dynamic coupling analysis of the entire valve opening and closing process and improving detection accuracy. By differentiating the displacement signal to obtain velocity and acceleration curves and identifying velocity abrupt changes and acceleration zero-crossing points, the start, end, and intermediate jamming moments of valve action can be accurately determined, achieving refined identification of abnormal actions. By mapping the pressure-displacement data of the opening and closing phases to the same coordinate system, a hysteresis loop was constructed, and the enclosing area and displacement deviation under the same pressure were calculated, transforming the sealing performance from a qualitative judgment to a quantifiable indicator, improving the objectivity of defect identification. A sealing performance index was constructed based on the hysteresis loop characteristics, and an action flexibility index was constructed based on velocity and acceleration characteristics, enabling the classification and judgment of internal leakage defects and action jamming defects. Addressing the characteristics of large-diameter, high-pressure valves with high inertia, fast response, and strong impact, this method can capture dynamic abnormal features, solving the problem that traditional static tests struggle to detect potential defects. It is suitable for special operating conditions such as high-yield offshore oil wells and high-speed injection and production in gas storage facilities. By using the coaxial arrangement and rigid connection structure of the housing assembly and the drive assembly, the displacement of the indicator rod and the movement of the valve stem are transmitted synchronously, so that the detection data can truly reflect the internal motion state of the valve and improve the detection method.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for testing a large-diameter, high-pressure hydraulic safety valve, characterized in that, include: Collect the hydraulic pressure signal inside the cylinder and the displacement signal of the mechanical movement of the indicator rod; The hydraulic pressure signal and the displacement signal are timestamped to generate synchronized time series data. The synchronized time series data is then preprocessed to generate a standard detection dataset; Based on the standard detection dataset, the pressure loading phase and the pressure unloading phase are identified; and the pressure loading phase is mapped to a valve opening phase, and the pressure unloading phase is mapped to a valve closing phase. The displacement signals during the valve opening and closing phases are differentiated to obtain the valve motion velocity curve and motion acceleration curve; the velocity change points and acceleration crossing zero points during the motion process are identified to determine the start time, end time, and intermediate jamming time of the valve action. The pressure-displacement data of the valve opening phase and the valve closing phase are mapped to the same coordinate system to construct a pressure-displacement hysteresis loop; and the area enclosed by the pressure-displacement hysteresis loop and the displacement deviation value of the opening curve and the closing curve at the same pressure point are determined. Based on the velocity mutation point, acceleration past zero point, enclosing area, and displacement deviation value, the valve's sealing performance index and operational flexibility index are generated, and the valve is determined to be defective.

2. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 1, characterized in that, When generating synchronized time series data, the following are included: Obtain the original timestamp sequences corresponding to the hydraulic pressure signal and the displacement signal; use the original timestamp sequence of the hydraulic pressure signal as the reference time axis to resample the original timestamp sequence of the displacement signal; fill in the data missing points in the resampling process by linear interpolation, and make the hydraulic pressure signal and the displacement signal have the same time interval and data length to form the synchronous time series data.

3. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 2, characterized in that, When generating the standard detection dataset, the following are included: The synchronized time series data is subjected to moving average filtering and normalization, and then arranged in chronological order to form the standard detection dataset.

4. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 1, characterized in that, When identifying the stress loading and stress unloading phases, the following should be included: The slope of the hydraulic pressure signal in the standard test dataset as a function of time is determined; the time period with a slope greater than zero is identified as the pressure loading stage; the time period with a slope less than zero is identified as the pressure unloading stage; and the time period with a slope equal to zero is identified as the pressure holding stage.

5. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 1, characterized in that, When obtaining the valve's velocity curve and acceleration curve, the following should be included: The displacement signal is differentiated once to obtain an instantaneous velocity data sequence, which constitutes the valve motion velocity curve; the instantaneous velocity data sequence is differentiated twice to obtain an instantaneous acceleration data sequence, which constitutes the motion acceleration curve.

6. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 5, characterized in that, When identifying abrupt velocity changes and accelerations past zero during motion, and determining the start, end, and intermediate jamming moments of valve action, the following steps are taken: In the valve movement speed curve, determine the location where the speed value undergoes a step change and mark it as the speed change point; In the acceleration curve, the position where the acceleration value changes from positive to negative or from negative to positive is identified and marked as the acceleration point that passes zero. The time corresponding to the first velocity mutation point is determined as the start time, the time corresponding to the last velocity mutation point is determined as the end time, and the time when the velocity is lower than the average speed is determined as the intermediate jamming time.

7. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 1, characterized in that, When constructing the pressure-displacement hysteresis loop, the following steps are included: Establish a two-dimensional rectangular coordinate system with hydraulic pressure as the abscissa and indicator rod displacement as the ordinate; Connect the pressure-displacement data points within the valve opening phase in chronological order to form the opening trajectory line; Connect the pressure-displacement data points within the valve closing phase in chronological order to form a closing trajectory line; The opening trajectory line and the closing trajectory line are closed to form the pressure-displacement hysteresis loop.

8. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 7, characterized in that, Determining the enclosing area of ​​the pressure-displacement hysteresis loop and the displacement deviation between the opening and closing curves at the same pressure point includes: The area of ​​the enclosed region between the opening trajectory line and the closing trajectory line is determined as the enclosed area; At the preset pressure sampling points, extract the ordinate values ​​corresponding to the opening trajectory line and the closing trajectory line, and determine the absolute value of the difference between the two as the displacement deviation value.

9. The testing method for a large-diameter, high-pressure hydraulic safety valve according to claim 1, characterized in that, When generating the sealing performance index and operational flexibility index of a valve, and determining whether the valve is defective, the following steps are taken: The sealing performance index is generated by weighting the enclosing area and displacement deviation value. The motion agility index is generated by statistical analysis based on the distribution density of the velocity abrupt change points and the number of accelerations passing zero points. The sealing performance index is compared with a preset sealing threshold. If the sealing performance index is greater than the sealing threshold, the valve is determined to have an internal leakage defect. The motion flexibility index is compared with a preset flexibility threshold. If the motion flexibility index is greater than the flexibility threshold, it is determined that the valve has a motion jamming defect.

10. A large-diameter, high-pressure hydraulic safety valve, used in the testing method for the large-diameter, high-pressure hydraulic safety valve as described in any one of claims 1-9, characterized in that, Includes housing components and drive components; The housing assembly, from top to bottom, includes a hydraulic cylinder, an actuator housing, a valve cover, a valve body, and a valve seat; the hydraulic cylinder, actuator housing, valve cover, valve body, and valve seat are all fixedly connected in sequence; the lower end of the hydraulic cylinder extends into the actuator housing, and the upper end of the valve cover extends into the actuator housing; the valve body and valve seat are fitted together to form a valve port; The drive assembly includes an indicator rod, a piston, a spring plate, a spring, a valve stem, and a valve plate. The top of the cylinder has a through hole that mates with the indicator rod, allowing the lower end of the indicator rod to extend into the cylinder. The lower end of the indicator rod is connected to the upper end of the piston. The lower end of the piston is connected to the upper end of the spring plate. The lower end of the spring plate has a through rod, and the upper end of the valve stem has a through hole. The through rod and the through hole connect to fix the lower end of the spring plate to the upper end of the valve stem. The spring plate and the valve stem are also circumferentially connected. A spring is provided, with its upper end fixed to the spring pressure plate and its lower end fixed to the upper end of the valve cover extending into the actuator housing. The valve cover has a sliding hole that mates with the valve stem, allowing the valve stem and valve cover to move and be fixed through a specific structure at the bottom of the valve stem. The valve plate also has a fixing groove that mates with a specific structure at the bottom of the valve stem, allowing the valve plate and valve stem to be fixedly connected through the cooperation of the specific structure and the fixing groove. The valve plate also has a flow hole that mates with the valve port.

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