A method and system for testing dynamic performance of a regulating valve under hot state working condition

Abstract

The present application relates to the technical field of valve performance test, and proposes a dynamic performance test method and system of regulating valve under hot state working condition, which realizes dynamic performance test of regulating valve under high-temperature and high-pressure hot state working condition, and comprises: a test pipeline for feeding test liquid medium, an upstream isolation valve V001, a measured regulating valve and a downstream regulating valve V002 arranged on the test pipeline; the measured regulating valve is provided with a valve positioner and a continuous valve position feedback unit; the valve positioner is used for receiving a target opening degree instruction, and according to the deviation between the target opening degree instruction and the actual valve position feedback of the measured regulating valve, the performance of the measured regulating valve can be dynamically detected on line through the set test method.

Description

Technical Field

[0001] This invention relates to the technical field of valve body performance testing, specifically to a method and system for testing the dynamic performance of a control valve under hot operating conditions. Background Technology

[0002] Control valves are critical fluid control devices in process systems, regulating process parameters such as temperature, pressure, and level by adjusting the flow rate of the medium. The operational performance of control valves directly affects the control quality, safety margin, and operational reliability of the process system. Focusing solely on the static performance of control valves under conventional test conditions is insufficient for engineering applications. Especially for control valves operating under complex conditions such as high temperature and high pressure, their actual service condition differs significantly from their factory or conventional test conditions. Therefore, it is necessary to establish dynamic performance testing methods under hot-state conditions that reflect the actual operating characteristics of control valves. This allows for a thorough evaluation of their actual performance before commissioning, thereby reducing commissioning risks, operational risks, and the resulting economic losses and safety hazards.

[0003] Existing performance tests for control valves mainly focus on steady-state performance parameters such as full-stroke action time, basic error, hysteresis, dead zone, start-end deviation, and rated stroke deviation. They lack evaluation methods for the valve's dynamic response characteristics, action process features, and applicability in automatic control loops. This results in difficulties in accurately reflecting the dynamic performance of control valves and predicting their performance under actual closed-loop control conditions. Furthermore, existing performance tests for control valves are mostly conducted under cold media conditions or no media conditions, failing to simulate the effects of thermal deformation and deflection of valve internals and the possible two-phase flow under actual high-temperature and high-pressure conditions. This leads to inconsistencies between factory test results and actual field performance, significant performance degradation under actual conditions, and even jamming or seizing. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a method and system for testing the dynamic performance of control valves under hot operating conditions, enabling dynamic performance testing of control valves under high temperature and high pressure conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: One or more embodiments provide a dynamic performance testing system for a control valve under hot operating conditions, including: a test pipeline for introducing a test liquid medium, an upstream isolation valve V001, a control valve under test, and a downstream control valve V002 installed on the test pipeline; The control valve under test is equipped with a valve positioner, an actuator, and a continuous valve position feedback unit; the continuous valve position feedback unit is used to collect the actual valve position feedback L of the control valve under test. The valve positioner is used to receive the target opening command and to provide feedback on the deviation between the target opening command and the actual valve position of the controlled valve under test.

[0006] In a further technical solution, a first limit switch LS1 and a second limit switch LS2 are also connected to the control valve under test. The first limit switch LS1 and the second limit switch LS2 are used to detect whether the control valve under test has reached the preset limit position.

[0007] In a further technical solution, the valve positioner and the actuator are connected to a third pressure transmitter, a fourth pressure transmitter, and a fifth pressure transmitter, which are used to collect the positioner inlet pressure P3, the positioner outlet pressure P4, and the actuator air chamber pressure P5 of the controlled valve under test, respectively.

[0008] A further technical solution involves installing a temperature transmitter TE, a flow transmitter FT, and a first pressure transmitter PT on the test pipeline between the upstream isolation valve V001 and the control valve under test, which are used to collect the medium temperature T, the medium flow rate Q, and the upstream pressure P1 of the control valve under test, respectively. A second pressure transmitter PT is installed downstream of the control valve under test to collect the pressure downstream of the control valve under test.

[0009] One or more embodiments provide a method for testing the dynamic performance of a control valve under hot operating conditions based on the above-described dynamic performance testing system for a control valve under hot operating conditions, comprising the following steps: After the upstream pressure and medium temperature of the control valve under test reach the preset test requirements, open the upstream isolation valve V001 of the control valve under test to warm up the pipe, and control the pressure difference and medium flow rate of the control valve under test within the set range by controlling the opening degree of the relevant valves. The control valve under test is controlled to be at the first specified opening degree, and the control valve under test is made to change to the second specified opening degree by multiple steps with a preset positive amplitude, and then to the first specified opening degree by multiple steps with a preset reverse amplitude. After each step control, the next step is executed after continuous valve position feedback and the positioner inlet pressure stabilizes. Based on the operating parameters of the control valve under test, the dynamic performance index of the control valve under test is calculated, and the dynamic performance evaluation result of the control valve under test under hot conditions is obtained.

[0010] A further technical solution involves controlling the pressure difference and medium flow rate upstream and downstream of the tested regulating valve within a set range by controlling the opening degree of relevant valves. The relevant valves include an upstream isolation valve V001 located upstream of the tested regulating valve and a downstream regulating valve V002 located downstream of the tested regulating valve.

[0011] A further technical solution is to preset the positive amplitude and the negative amplitude to be the same size.

[0012] A further technical solution is to determine whether the current state is stable based on the continuous valve position feedback L and the upstream pressure P1 of the valve under test after each step action is completed. After the continuous valve position feedback L and the upstream pressure P1 of the valve under test are stable, the next step action is executed. During the step process, by controlling the valve opening of the upstream isolation valve V001 and the downstream regulating valve V002, the pressure difference and medium flow rate of the measured regulating valve are controlled within the set range.

[0013] Further technical solutions include the following operating parameters for the tested control valve: upstream and downstream pressures, flow rates, and temperature of the medium flowing in the test pipeline; continuous valve position feedback L and action commands; and dynamic performance indicators for the tested control valve, including the jamming index, overshoot index, downstroke index, action time, pure hysteresis time, and steady-state valve position deviation.

[0014] Further technical solutions include calculating dynamic performance indicators for each step response process, including the stuttering index, overshoot index, undershoot index, action time, pure lag time, and steady-state valve position deviation. The stuttering index is specifically defined as follows: from the moment the action command is issued until the preset observation period, if the maximum value of the change in the continuous valve position feedback relative to the initial steady-state valve position is less than the preset threshold, the stuttering index is set to 1, indicating that the tested control valve has stuttering; if the maximum value of the change in the continuous valve position feedback relative to the initial steady-state valve position is greater than or equal to the preset threshold, the stuttering index is set to 0, indicating that the tested control valve does not have stuttering. The overshoot index is defined as the absolute value of the ratio of the maximum instantaneous deviation (FD) of the actual valve position from the command in the same direction during the response process to the difference (DA) between the final steady-state valve position and the initial steady-state valve position. The undershoot index is defined as the absolute value of the ratio of the maximum instantaneous deviation (DC) of the actual valve position from the final steady-state valve position in the opposite direction to the command during the response process to the difference (DA) between the final steady-state valve position and the initial steady-state valve position. Action time is used to characterize the total time required for a control valve to reach a stable valve position from the start of its action. Pure time delay is used to characterize the time delay between receiving an action command and the actual start of action of a control valve; Steady-state valve position deviation is used to characterize the deviation between the actual stable position of the control valve after the response ends and the target of the action command.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The testing system of this invention, by setting up an upstream isolation valve V001, a controlled valve under test, and a downstream controlled valve V002 on the test pipeline, and combining a valve positioner and a continuous valve position feedback unit, constructs a testing system capable of providing feedback and dynamic observation of the opening degree of the controlled valve under test. This enables measurable and repeatable simulation testing of the dynamic response process of the controlled valve under test. Therefore, it addresses the shortcomings of existing systems that can only obtain steady-state performance parameters and lack means to evaluate the dynamic response characteristics and action process features of the controlled valve. It more realistically reproduces the dynamic working state of the controlled valve in the automatic control loop and provides a system basis for simulating actual operating conditions such as pressure and flow under hot conditions, improving the accuracy of assessing the applicability of the controlled valve to actual operation.

[0016] The testing method of this invention involves warming up the control valve after the upstream pressure and medium temperature reach the preset test requirements, and controlling the opening of relevant valves to maintain the pressure difference and medium flow rate between the upstream and downstream of the control valve within a set range. This allows the control valve to be tested under hot conditions close to actual online operation. Simultaneously, by controlling the control valve to undergo multiple forward and reverse step changes between a first and second specified opening, and performing the next step change only after continuous valve position feedback and stabilization of the positioner inlet pressure after each step change, dynamic testing of the control valve's dynamic response process can be achieved. Furthermore, by calculating dynamic performance indicators and generating evaluation results, the method can quantitatively reflect the smoothness of the control valve's operation, response speed, dynamic stability, and steady-state regulation accuracy. This overcomes the shortcomings of existing technologies that lack dynamic performance evaluation methods, and improves the accuracy of predicting the field operating performance, safety, and reliability of control valves.

[0017] The advantages of the present invention, as well as its additional advantages, will be described in detail in the following specific embodiments. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof.

[0019] Figure 1 This is a schematic diagram of the dynamic performance testing system for a control valve under hot working conditions according to Embodiment 1 of the present invention; Figure 2 This is a flowchart of the dynamic performance test of the hot-state control valve in Embodiment 2 of the present invention; Figure 3(a) is a pressure test curve of the dynamic performance test example of the control valve under hot conditions in Example 2; Figure 3(b) is a valve position test curve of the example of dynamic performance test of the control valve under hot working conditions in Example 2; Figure 4This is a schematic diagram of the single step response process in Embodiment 2 of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. It should be noted that, without conflict, the various embodiments and features within those embodiments can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0023] Example 1 In one or more of the technical solutions disclosed in the embodiments, such as Figure 1 As shown, a dynamic performance testing system for a control valve under hot operating conditions includes: a test pipeline for introducing a test liquid medium, an upstream isolation valve V001, a control valve under test, and a downstream control valve V002 installed on the test pipeline; The control valve under test is equipped with a valve positioner, an actuator, and a continuous valve position feedback unit; the continuous valve position feedback unit is used to collect the actual valve position feedback L of the control valve under test. The valve positioner is used to receive the target opening command and to provide feedback on the deviation between the target opening command and the actual valve position of the controlled valve under test. Through the above technical solution, this embodiment sequentially sets up an upstream isolation valve V001, a control valve under test, and a downstream control valve V002 on the test pipeline. A valve positioner and a continuous valve position feedback unit are also installed on the control valve under test, enabling it to receive the target opening command in a pipeline environment with the test liquid medium flowing through it. The continuous valve position feedback unit collects the actual valve position feedback L in real time. This embodiment's system does not only detect steady-state performance parameters such as the full-stroke action time, basic error, hysteresis, dead zone, start-end deviation, and rated stroke deviation of the control valve under test, but also continuously acquires the response process of the control valve to the target opening command, valve position following, and action adjustment process during the test. This allows for the evaluation of the dynamic response characteristics, action process features, and closed-loop control applicability of the control valve under test. Compared to existing test methods that rely solely on steady-state performance parameters, this system can more accurately reflect the dynamic working state of the control valve in the automatic control loop, which is beneficial for predicting its operating performance under actual closed-loop control conditions.

[0024] Simultaneously, by introducing test liquid medium through the test pipeline and coordinating the flow state of the medium in the test pipeline using the upstream isolation valve V001 and the downstream regulating valve V002, the tested regulating valve can be dynamically tested under pipeline conditions with medium action. This avoids the problem that test results cannot reflect the actual operating state when tested only under conditions without medium or in a cold state. It can improve the consistency between the factory test results of the regulating valve and the actual operating performance on site, and reduce the risk of dynamic performance degradation, unstable operation, jamming or seizure of the regulating valve under actual working conditions.

[0025] In some embodiments, a first limit switch LS1 and a second limit switch LS2 are also connected to the control valve under test. The first limit switch LS1 and the second limit switch LS2 are used to collect the limit switch feedback signal of the control valve. LS1 and LS2 are used to detect whether the control valve under test has reached the preset limit position. During the test, the system collects both the continuous opening signal L of the valve and the two limit switch signals LS1 and LS2 to comprehensively judge the position and action state of the control valve under test.

[0026] A specific structure for the tested control valve includes a valve body, a valve core / disc, a valve stem, and a valve seat. The valve core or disc is disposed inside the valve body and cooperates with the valve seat to change the flow area. One end of the valve stem is connected to the valve core or disc, and the other end is connected to the output end of the actuator. The actuator drives the valve stem to move axially, thereby causing the valve core or disc to move relative to the valve seat to adjust the opening degree of the tested control valve.

[0027] This embodiment uses a continuous valve position feedback unit to provide feedback on the actual valve position signal of the controlled valve under test. One possible implementation includes a fixed part and a movable part. The fixed part is fixedly mounted on the upper bracket of the valve body, the valve cover, the actuator mounting bracket, or the actuator housing; the movable part is connected to the valve stem. Thus, when the actuator drives the valve stem to move up and down, the movable part is displaced relative to the fixed part.

[0028] Optionally, the continuous valve position feedback unit can be any one of a linear displacement sensor, an LVDT displacement sensor, a magnetostrictive displacement sensor, a potentiometer-type displacement sensor, or an encoder feedback mechanism. This continuous valve position feedback unit obtains the current stroke position of the valve stem by detecting the axial displacement of the valve stem relative to a fixed reference position connected to the fixed part, and converts this stroke position into the continuous valve position feedback L of the controlled valve under test. It is feasible; the continuous valve position feedback unit can be integrated into the valve positioner to achieve the function of acquiring feedback signals.

[0029] In one specific embodiment, the first limit switch LS1 is fixedly installed on the upper bracket of the valve body, the outside of the valve cover, the actuator mounting bracket, or the actuator housing of the control valve under test; corresponding to the first limit switch LS1, a first trigger element, such as a stop block, cam, trigger plate, or magnetic trigger element, is provided on the valve stem or on the actuator output rod that moves synchronously with the valve stem; When the valve stem moves to the first preset position, the first triggering element contacts, presses, approaches or triggers the first limit switch LS1, causing the first limit switch LS1 to output the first limit feedback signal.

[0030] Optionally, the first limit switch LS1 can be used to detect whether the control valve under test has reached the fully closed position. At this time, when the valve stem of the control valve under test drives the valve core or valve disc to move to a preset position that is in contact with or close to the valve seat, the first limit switch LS1 is triggered, thereby outputting a fully closed signal.

[0031] In one specific embodiment, the second limit switch LS2 is fixedly mounted on the upper bracket of the valve body, the outer side of the valve cover, the actuator mounting bracket, or the actuator housing. Corresponding to the second limit switch LS2, a second trigger element, such as a stop block, a cam, a trigger plate, or a magnetic trigger element, is provided on the valve stem or on the actuator output rod that moves synchronously with the valve stem.

[0032] When the valve stem moves to the second preset position, the second triggering element contacts, presses, approaches, or triggers the second limit switch LS2, causing the second limit switch LS2 to output the second limit feedback signal.

[0033] Optionally, the second limit switch LS2 can be used to detect whether the controlled valve under test has reached the fully open position. At this time, when the valve stem drives the valve core or valve disc to move to the maximum set stroke position away from the valve seat, the second trigger triggers the second limit switch LS2, thereby outputting a fully open signal.

[0034] Furthermore, the valve positioner is connected to the actuator of the control valve under test and is equipped with a third pressure transmitter, a fourth pressure transmitter and a fifth pressure transmitter, which are used to collect the positioner inlet pressure P3, the positioner outlet pressure P4 and the actuator air chamber pressure P5, respectively. The third pressure transmitter has a pressure sensor (P3) that measures the air supply pressure entering the valve positioner. This sensor is used to detect whether the air supply conditions at the front end of the positioner are normal. It determines whether the air supply is stable and meets the test requirements, serves as one of the criteria for determining whether the valve has entered a stable state after each step change, and eliminates false alarms such as slow action, jamming, and overshoot caused by air supply fluctuations.

[0035] The fourth pressure transmitter is used to measure the control pressure output by the positioner to the actuator, to determine whether the positioner has correctly issued the drive pressure; to judge whether the positioner outputs pressure in a timely and accurate manner according to the control command; to analyze whether the positioner has output hysteresis, insufficient output, fluctuation or abnormal jump; and to distinguish whether the problem is in the positioner output stage or in the actuator / valve body mechanical stage when the valve action is abnormal.

[0036] The fifth pressure transmitter is used to measure the actual pressure built up in the actuator's gas chamber to determine whether the actuator has truly generated an effective driving force to move the valve; to determine whether the actuator has truly obtained sufficient driving force; to determine whether the pressure output by the positioner has been effectively transmitted to the actuator; and to analyze whether the actuator has problems such as leakage, slow pressure build-up, increased friction, or insufficient thrust. The third, fourth, and fifth pressure transmitters in this embodiment are used to monitor in real time the air supply status, positioner pressure regulation output status, and actuator pressure drive status in the pneumatic control link of the controlled valve under test. This ensures the stability of the air supply and control conditions during the step test. Furthermore, when the controlled valve experiences jamming, slow action, increased pure hysteresis, overshoot, undershoot, or abnormal steady-state deviation, the causes of the abnormalities are analyzed in segments and the fault is located.

[0037] In a further technical solution, in order to control the test conditions on the test pipeline, a temperature transmitter TE, a flow transmitter FT and a first pressure transmitter PT are also installed on the test pipeline between the upstream isolation valve V001 and the control valve under test, which are used to collect the medium temperature T, the medium flow rate Q and the upstream pressure P1 of the control valve under test, respectively. A second pressure transmitter PT is installed downstream of the control valve under test to collect the pressure downstream of the control valve under test. Furthermore, to achieve unified data acquisition and processing, the system also includes a data acquisition and storage module that is electrically or communicatively connected to the aforementioned sensors, limit switches, continuous valve position feedback units, and valve positioners; a data processing module connected to the data acquisition and storage module; and a display module connected to the data processing module.

[0038] The data acquisition and storage module is used to acquire, record and store in real time the medium temperature T, medium flow rate Q, upstream pressure P1 of the measured regulating valve, downstream pressure P2 of the measured regulating valve, continuous valve position feedback L, limit switch feedback LS1 and LS2, positioner inlet pressure P3, positioner outlet pressure P4 and actuator air chamber pressure P5. The data processing module is used to send opening control commands to the valve positioner and process the collected operating parameters to obtain dynamic performance indicators of the tested control valve under hot conditions, such as smoothness of action, action time, pure delay time, steady-state valve position deviation, overshoot and / or undershoot. The display module is used to display various real-time parameters, change curves, and dynamic performance evaluation results during the test.

[0039] In some embodiments, the test pipeline can provide hot medium conditions that match the actual operating state of the control valve under test. By controlling the opening of the upstream isolation valve V001 and the downstream control valve V002, the pressure difference and medium flow rate of the control valve under test can be adjusted, so that the control valve under test is in the preset high temperature, high pressure and target flow conditions, thereby realizing the simulation test of the hot dynamic performance of the control valve under test.

[0040] Optionally, the control valve under test is a pneumatic control valve. The valve positioner is used to receive the step command signal output by the data processing module and adjust the air pressure entering the actuator according to the step command. The third, fourth, and fifth pressure transmitters are respectively arranged at the positioner inlet, the positioner output end, and the actuator air chamber to monitor the air pressure change in the control valve in real time. Combined with the continuous valve position feedback L and the limit switch feedbacks LS1 and LS2, the control valve action response process is comprehensively evaluated.

[0041] Example 2 Based on Embodiment 1, this embodiment provides a method for testing the dynamic performance of a control valve under hot operating conditions, based on the dynamic performance testing system for a control valve under hot operating conditions described in Embodiment 1. Figures 2 to 4 As shown, it includes the following steps: Step 1: After the upstream pressure and medium temperature of the control valve under test reach the preset test requirements, open the upstream isolation valve V001 of the control valve under test to warm up the pipe, and control the pressure difference and medium flow rate of the control valve under test within the set range by controlling the opening degree of the relevant valves. Step 2: Control the control valve under test to the first specified opening degree, and make the control valve under test change to the second specified opening degree in multiple steps with a preset positive amplitude, and then change to the first specified opening degree in multiple steps with a preset reverse amplitude. After each step, the next step is executed after continuous valve position feedback and the positioner inlet pressure stabilizes. Step 3: Calculate the dynamic performance index of the control valve under test based on its operating parameters, and obtain the dynamic performance evaluation result of the control valve under test under hot conditions. The above implementation steps involve warming up the pipeline before the upstream pressure and medium temperature of the controlled valve reach the preset test requirements, and controlling the opening of relevant valves to maintain the pressure difference and medium flow rate between the upstream and downstream of the controlled valve within the set range. This allows the controlled valve to be tested under hot conditions close to actual online operation, thus solving the problem that existing tests are mostly conducted under cold medium conditions or without medium conditions, making it difficult to truly reflect the actual high-temperature and high-pressure operating state. Simultaneously, by controlling the controlled valve to perform multiple step changes between the first and second specified opening degrees according to preset positive and negative amplitudes, and providing continuous valve position feedback and positioner after each step change... By performing the next step test only after the inlet pressure has stabilized, the dynamic response process of the tested control valve can be repeatedly tested, improving the stability of the testing process and the consistency of the test results. Furthermore, by calculating dynamic performance indicators based on the operating parameters of the tested control valve and forming dynamic performance evaluation results under hot conditions, the smoothness of the control valve's operation, response speed, dynamic stability, and steady-state regulation accuracy can be quantitatively reflected. This overcomes the shortcomings of existing technologies, which can only obtain steady-state performance parameters and lack evaluation methods for the valve's dynamic response characteristics and the applicability of actual closed-loop control, thereby improving the accuracy of predicting the field operating performance, safety, and reliability of the control valve.

[0042] In step 1, the pressure difference and medium flow rate of the upstream and downstream of the tested regulating valve are controlled within a set range by controlling the opening degree of the relevant valves. The relevant valves include an upstream isolation valve V001 located upstream of the tested regulating valve and a downstream regulating valve V002 located downstream of the tested regulating valve. Through the coordinated adjustment of the upstream isolation valve V001 and the downstream regulating valve V002, the tested regulating valve is kept under preset pressure, flow rate and temperature conditions during the test.

[0043] In step 2, the opening degree of the control valve under test is controlled by the connected positioner; Optionally, the preset positive amplitude and the preset negative amplitude can be the same; Once the upstream pressure and medium temperature of the tested control valve reach the test requirements, the data processing module sends an opening control command to the positioner of the tested control valve, causing the tested control valve to be at the first specified opening. After the first specified opening stabilizes, a positive step control command is sent to the positioner, causing the tested control valve to perform multiple step actions with a preset positive amplitude of +X% until it changes to the second specified opening. After the tested control valve reaches the second specified opening, a reverse step control command is sent to the positioner, causing the tested control valve to perform multiple step actions with a preset reverse amplitude of -X% until it returns to the first specified opening.

[0044] After each step action is completed, the current state is determined to be stable based on the continuous valve position feedback L and the upstream pressure P1 of the valve being measured. The next step action is then executed after the continuous valve position feedback L and the upstream pressure P1 of the valve being measured have stabilized.

[0045] Furthermore, throughout the entire step process in step 2, by controlling the valve opening of the upstream isolation valve V001 and the downstream regulating valve V002, the pressure difference and medium flow rate of the regulating valve under test are controlled within the set range to ensure that the dynamic performance test is carried out under the preset hot working conditions.

[0046] Optionally, in step 3, the operating parameters of the control valve under test may include the upstream and downstream pressures, flow rate, and temperature of the medium flowing in the test pipeline; the dynamic performance indicators of the control valve under test may include the jamming index, overshoot index, downstroke index, action time, pure hysteresis time, and steady-state valve position deviation. In one or more embodiments, after completing the hot-state step test of the control valve under test, the dynamic performance of the control valve under test is calculated and evaluated based on the action command signal, continuous valve position feedback signal L, limit switch feedback signals LS1 and LS2 collected during the test, as well as the positioner inlet pressure P3, positioner outlet pressure P4 and actuator air chamber pressure P5.

[0047] In this embodiment, a single step response process can be selected as the evaluation object, such as... Figure 4 As shown, the following definitions apply: t1 is the moment the control valve receives the action command, t2 is the moment the control valve actually begins to act, and t3 is the moment the control valve reaches its stable position; A is the initial steady-state valve position before the control valve acts, D is the final steady-state valve position after the control valve acts, E is the target valve position corresponding to the action command, F is the maximum instantaneous value of the actual valve position exceeding the final steady-state valve position along the direction of command change during the response process, and C is the maximum instantaneous value of the actual valve position deviating from the direction opposite to the direction of command change during the response process. The above steady-state values ​​can be obtained by averaging or filtering the continuous valve position feedback L within a preset time window to reduce the impact of sampling noise on the evaluation results.

[0048] In a specific embodiment, the dynamic performance indicators include a stiction index, an overshoot index, an undershoot index, an action time, a pure lag time, and a steady-state valve position deviation, which are calculated for each step response process respectively, as follows: The stiction index is used to characterize whether the tested regulating valve can start in time after receiving an action command, and it reflects whether there are obvious problems such as significant increase in static friction, valve core jamming, insufficient actuator output, or transmission hysteresis of the regulating valve under thermal working conditions; Specifically for the stiction index: within the preset observation duration starting from the moment the action command is issued, if the maximum value of the variation of the continuous valve position feedback relative to the initial steady-state valve position is less than the preset threshold, the stiction index is set to 1, indicating that the tested regulating valve has stiction; if the maximum value of the variation of the continuous valve position feedback relative to the initial steady-state valve position is greater than or equal to the preset threshold, the stiction index is set to 0, indicating that the tested regulating valve has no stiction; the preset observation duration and the valve position variation judgment threshold ε for the tested regulating valve Δt; the stiction index can be defined as: ; wherein, is the valve position of the regulating valve at the moment; A is the initial steady-state valve position of the regulating valve before action; wherein, K k =1 indicates that the valve position has not changed effectively within the preset observation duration, and it can be determined that the tested regulating valve has stiction; K k =0 indicates that the valve position has changed effectively, and it can be determined that no stiction occurs in the tested regulating valve. This indicator mainly reflects the starting capability and action smoothness of the regulating valve. A larger stiction index indicates that the regulating valve is more prone to starting difficulty or mechanical jamming under thermal working conditions.

[0049] The overshoot index is defined as the absolute value of the ratio of the maximum instantaneous deviation (F-D) of the actual valve position in the same direction as the command beyond the final steady-state valve position during the response process, to the difference (D-A) between the final steady-state valve position and the initial steady-state valve position; the overshoot index can be defined as: ; wherein, F is the maximum instantaneous deviation point of the actual valve position in the same direction as the command during the response process, D is the final steady-state valve position, and A is the initial steady-state valve position.

[0050] Optionally, when Ko ≥ 20%, the valve can be rated as excessive overshoot; when 10% < Ko ≤ 20%, the valve can be rated as moderate overshoot; when 3% < Ko ≤ 10%, the valve can be rated as low overshoot. A larger overshoot index indicates that the regulating valve is prone to an inertial response exceeding the target or over-regulation after receiving a step command, which indicates poor dynamic stability and may lead to increased fluctuation of the process variable in the automatic control loop.

[0051] The overshoot index is used to characterize the degree to which the control valve exceeds the final steady-state valve position along the direction of command change during a step response. It reflects the overshoot characteristics of the control valve's dynamic response and the stability of the positioning control. The undershoot index is defined as the absolute value of the ratio of the maximum instantaneous deviation (DC) of the actual valve position from the final steady-state valve position during the response process to the difference (DA) between the final steady-state valve position and the initial steady-state valve position. The undershoot index characterizes the degree to which the control valve deviates in the opposite direction to the command change during a step response. It reflects whether there are significant reverse offset, pullback, hysteresis, or mechanical looseness in the initial stage of the response. It can be defined as: ; Where C is the point where the actual valve position deviates from the command in the opposite direction during the response process, D is the final steady-state valve position, and A is the initial steady-state valve position.

[0052] Specifically, when K u When the percentage is ≥20%, the valve can be assessed as having excessive underflush; when it is 10%... <K u When the percentage is ≤20%, the valve can be assessed as having moderate underflow; when it is 3%... <K u When the understroke rate is ≤10%, the valve can be assessed as having a low understroke. The larger the understroke index, the more obvious the reverse deviation of the control valve is in the initial stage of response. This usually means that there is strong hysteresis, backlash, or additional interference under thermal conditions in the valve's mechanical transmission system, actuator, or positioning control.

[0053] Action time, or activating time, characterizes the total time required for a control valve to reach a stable position from the start of its action; it reflects the speed at which the control valve completes one effective regulating action. Action time Ta can be defined as: ; in, The moment when the control valve begins to operate. The moment when the control valve reaches a stable valve position; In one specific implementation, the moment when the continuous valve position feedback L first continuously exceeds the starting valve position change determination threshold ε can be determined as... The moment when the valve position enters and remains within the allowable fluctuation range of the final steady-state valve position can be determined as... The allowable fluctuation range can be set to ±1% of the rated stroke or other ranges as required by the test.

[0054] Optionally, when the action time Ta ≤ 6 seconds, the control valve can be judged to have good action performance; when Ta > 10 seconds, the control valve can be judged to have slow action performance. The shorter the action time, the faster the control valve completes the regulation process under hot conditions; the longer the action time, the slower the actuator response, the greater the mechanical resistance, or the more obvious the oscillation in the control process.

[0055] Pure time delay characterizes the time interval between receiving an action command and the actual start of action of a control valve, reflecting the valve's command response speed and starting sensitivity. Pure time delay Td can be defined as: ; in, The moment when the action command is issued. This refers to the moment when the control valve begins to operate.

[0056] Specifically, when T d If the response time is ≤1 second, the control valve can be judged to have good response speed; when T d A response time greater than 2 seconds indicates a slow control valve response. The shorter the pure lag time, the faster the control valve can establish an effective action after receiving the command; the longer the pure lag time, the more significant the delay in the stages of air source input, positioner pressure adjustment, actuator pressure building, or valve stem / core activation.

[0057] Optionally, the source of pure lag time can be analyzed in segments by combining the changes of P3, P4 and P5, in order to determine whether the lag mainly originates from the air source side, the positioner side, the actuator side or the valve body mechanical side.

[0058] In one specific implementation, the source of hysteresis can be determined based on the order of changes in P3, P4, P5, and L: when P3 is stable but P4 remains unchanged, the hysteresis is mainly caused by the valve positioner; when P4 has changed but P5 has not changed in time, the hysteresis is mainly caused by the pressure-building link of the actuator; when P5 has changed but L has not changed in time, the hysteresis is mainly caused by the mechanical moving parts of the valve stem, valve core, or valve seat of the controlled valve under test; when P3 itself has obvious fluctuations or is insufficient, the hysteresis is related to abnormal external air source conditions.

[0059] By using the above methods, not only can the total pure delay time of the control valve be obtained, but the source of the pure delay time can also be decomposed, thereby improving the ability to identify the causes of abnormal dynamic performance of the control valve under hot operating conditions, and providing a basis for judging whether the control valve has problems such as abnormal positioner response, slow pressurization of the actuator, mechanical jamming or insufficient air supply.

[0060] The steady-state valve position deviation is used to characterize the deviation between the actual stable position of the regulating valve after the response ends and the target of the action command, which reflects the final positioning accuracy and steady-state regulation capability of the regulating valve. The steady-state valve position deviation Es can be defined as: ; where D is the final steady-state valve position, and E is the target valve position corresponding to the action command.

[0061] Optionally, when Es≤1%, the regulating valve can be determined to have high regulation accuracy; when 1%<Es≤2.5%, the regulating valve can be determined to have medium regulation accuracy; when Es>2.5%, the regulating valve can be determined to have low regulation accuracy. A smaller steady-state valve position deviation indicates that the regulating valve can more accurately reach and maintain the target opening; a larger steady-state valve position deviation indicates that the positioning accuracy of the regulating valve decreases under hot state working conditions, and there may be problems such as thermal deformation of the valve core, increased friction, insufficient positioner calibration, or insufficient driving force of the actuator of the regulating valve.

[0062] In this embodiment, through comprehensive evaluation of the above-mentioned stuttering index, overshoot index, undershoot index, action time, pure lag time and steady-state valve position deviation, the dynamic performance of the tested regulating valve under hot state working conditions can be comprehensively characterized from multiple dimensions such as starting capability, response speed, process stability, action smoothness and final regulation accuracy. Compared with the existing test methods that only evaluate steady-state performance parameters such as basic error, return difference and dead zone, this embodiment can more truly reflect the dynamic operation performance of the regulating valve in the automatic control loop, thereby improving the evaluation accuracy of the on-site applicability and operation reliability of the regulating valve.

[0063] Testing the dynamic performance of the regulating valve under hot state working conditions according to this embodiment can test and determine whether the dynamic performance of the regulating valve under actual hot state working conditions meets the requirements before the regulating valve leaves the factory or is officially put into operation, detect and eliminate faults in advance, and ensure the safety and reliability of the commissioning and production process.

[0064] The experimental results are shown in Figure 3(a) and Figure 3(b). Figure 3(a) is a pressure test curve diagram of the dynamic performance test of the regulating valve under hot state working conditions, with time as the abscissa and pressure as the ordinate, showing the variation of the upstream pressure of the test valve and the actuator air chamber pressure with the test time; Figure 3(b) is a valve position test curve diagram of the dynamic performance test of the regulating valve under hot state working conditions, with time as the abscissa and valve position percentage as the ordinate, showing the variation of the valve position command and valve position feedback with the test time. The valve position command gradually increases from the closed position to a relatively large opening according to the stepwise regulation rule, and then gradually decreases back to the closed position; the valve position feedback basically follows the change of the valve position command, and the overall coincidence degree of the two curves is high, indicating that the regulating valve can respond to the opening regulation command relatively accurately under hot state working conditions, and has good dynamic tracking performance and operation stability.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0066] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A dynamic performance testing system for a control valve under hot operating conditions, characterized in that, include: The test pipeline is used to introduce the test liquid medium, and the upstream isolation valve V001, the control valve under test and the downstream control valve V002 are installed on the test pipeline; The control valve under test is equipped with a valve positioner, an actuator, and a continuous valve position feedback unit; the continuous valve position feedback unit is used to collect the actual valve position feedback L of the control valve under test. The valve positioner is used to receive the target opening command and to provide feedback on the deviation between the target opening command and the actual valve position of the controlled valve under test.

2. The dynamic performance testing system for a control valve under hot operating conditions as described in claim 1, characterized in that, The control valve under test is also equipped with a first limit switch LS1 and a second limit switch LS2. The first limit switch LS1 and the second limit switch LS2 are used to detect whether the control valve under test has reached the preset limit position.

3. The dynamic performance testing system for a control valve under hot operating conditions as described in claim 1, characterized in that, The valve positioner and actuator are connected to a third, fourth, and fifth pressure transmitter, which are used to collect the positioner inlet pressure P3, the positioner outlet pressure P4, and the actuator air chamber pressure P5 of the controlled valve being measured, respectively.

4. The dynamic performance testing system for a control valve under hot operating conditions as described in claim 1, characterized in that, On the test pipeline between the upstream isolation valve V001 and the control valve under test, a temperature transmitter TE, a flow transmitter FT and a first pressure transmitter PT are also installed, which are used to collect the medium temperature T, the medium flow rate Q and the upstream pressure P1 of the control valve under test, respectively. A second pressure transmitter PT is installed downstream of the control valve under test to collect the pressure downstream of the control valve under test.

5. A method for testing the dynamic performance of a control valve under hot operating conditions based on the dynamic performance testing system for a control valve under hot operating conditions described in Example 1, characterized in that, Includes the following steps: After the upstream pressure and medium temperature of the control valve under test reach the preset test requirements, open the upstream isolation valve V001 of the control valve under test to warm up the pipe, and control the pressure difference and medium flow rate of the control valve under test within the set range by controlling the opening degree of the relevant valves. The control valve under test is controlled to be at the first specified opening degree, and the control valve under test is made to change to the second specified opening degree by multiple steps with a preset positive amplitude, and then to the first specified opening degree by multiple steps with a preset reverse amplitude. After each step control, the next step is executed after continuous valve position feedback and the positioner inlet pressure stabilizes. Based on the operating parameters of the control valve under test, the dynamic performance index of the control valve under test is calculated, and the dynamic performance evaluation result of the control valve under test under hot conditions is obtained.

6. The method for testing the dynamic performance of a control valve under hot operating conditions as described in claim 5, characterized in that, The pressure difference and medium flow rate upstream and downstream of the tested regulating valve are controlled within a set range by controlling the opening degree of the relevant valves. The relevant valves include the upstream isolation valve V001 located upstream of the tested regulating valve and the downstream regulating valve V002 located downstream of the tested regulating valve.

7. The method for testing the dynamic performance of a control valve under hot operating conditions as described in claim 5, characterized in that, The preset positive amplitude and the preset negative amplitude are the same.

8. The method for testing the dynamic performance of a control valve under hot operating conditions as described in claim 5, characterized in that, After each step action is completed, the current state is determined to be stable based on the continuous valve position feedback L and the upstream pressure P1 of the valve being measured. After the continuous valve position feedback L and the upstream pressure P1 of the valve being measured are stable, the next step action is executed. During the step process, by controlling the valve opening of the upstream isolation valve V001 and the downstream regulating valve V002, the pressure difference and medium flow rate of the measured regulating valve are controlled within the set range.

9. The method for testing the dynamic performance of a control valve under hot operating conditions as described in claim 5, characterized in that, The operating parameters of the control valve under test may include the upstream and downstream pressures, flow rates, and temperature of the medium flowing in the test pipeline, as well as the continuous valve position feedback L and action commands of the control valve under test; the dynamic performance indicators of the control valve under test include the jamming index, overshoot index, undershoot index, action time, pure hysteresis time, and steady-state valve position deviation.

10. The method for testing the dynamic performance of a control valve under hot operating conditions as described in claim 9, characterized in that: Dynamic performance indices calculated for each step response process include the stuttering index, overshoot index, undershoot index, action time, pure lag time, and steady-state valve position deviation. The stuttering index is specifically defined as follows: from the moment the action command is issued until the preset observation period, if the maximum value of the change in the continuous valve position feedback relative to the initial steady-state valve position is less than the preset threshold, the stuttering index is set to 1, indicating that the tested control valve has stuttering; if the maximum value of the change in the continuous valve position feedback relative to the initial steady-state valve position is greater than or equal to the preset threshold, the stuttering index is set to 0, indicating that the tested control valve does not have stuttering. The overshoot index is defined as the absolute value of the ratio of the maximum instantaneous deviation (FD) of the actual valve position from the command in the same direction during the response process to the difference (DA) between the final steady-state valve position and the initial steady-state valve position. The undershoot index is defined as the absolute value of the ratio of the maximum instantaneous deviation (DC) of the actual valve position from the final steady-state valve position in the opposite direction to the command during the response process to the difference (DA) between the final steady-state valve position and the initial steady-state valve position. Action time is used to characterize the total time required for a control valve to reach a stable valve position from the start of its action. Pure time delay is used to characterize the time delay between receiving an action command and the actual start of action of a control valve; Steady-state valve position deviation is used to characterize the deviation between the actual stable position of the control valve after the response ends and the target of the action command.

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