A pneumatic switch valve online fault diagnosis system and diagnosis method

Abstract

The present invention specifically relates to an online fault diagnosis system and method for pneumatic switch valves. The system includes an air pressure detection module for obtaining the air pressure parameter P of the pneumatic actuator; a valve opening detection module for obtaining the valve opening parameter ZT; an electrical signal acquisition module for obtaining the electrical signal parameter D of the solenoid valve; a control module for transmitting the operating voltage signal of the main controller and sending diagnostic test instructions to the test switch; a setting module for performing a setting operation and generating diagnostic test instructions, and generating a parameter diagnosis basis based on the various parameters obtained during the setting operation; and an analysis module for receiving the various parameters in the diagnostic operation and obtaining detailed fault information of the pneumatic switch valve through comparative analysis based on the parameter diagnosis basis. The system can comprehensively diagnose faults of the pneumatic switch valve as a whole and its individual components, meeting the safety requirements of advanced intelligent production.

Description

Technical Field

[0001] The present invention relates to the technical field of switch valve equipment, and in particular to an online fault diagnosis system and a diagnosis method for a pneumatic switch valve. Background Art

[0002] In process industries such as oil refining, petrochemicals, chemicals, electric power, metallurgy, papermaking, pharmaceuticals, and light industry, pneumatic on-off valves are used to control the on / off and directional switching of process media (liquids, gases, or mixtures). Their main components and control systems consist of valves (e.g., ball valves, butterfly valves, gate valves, and globe valves), pneumatic actuators (cylinders, pistons, diaphragms, and forks) that open and close the valves, solenoid valves that control the actuators, limit switches that determine the piston's position, and a master controller that controls the solenoid valves. The reliability and precise control performance of pneumatic on-off valves are crucial to equipment safety and stability.

[0003] Over extended operation, pneumatic on-off valves may be susceptible to mechanical wear, corrosion from media, and aging from temperature and pressure environments, leading to component failures, particularly failure or performance degradation of core components such as solenoid valves, cylinders, and valves. These failures can prevent valves from properly responding to commands from the master controller or delay their response, further causing equipment downtime or even production accidents. For example, some emergency shut-off, isolation, drain, or vent valves, which perform safety functions, remain inactive for extended periods under normal circumstances. In emergencies, their ability to operate as required or their refusal to operate warrants attention. Similarly, for frequently operated on-off valves, the components (solenoid valves, cylinders, valves, control air circuits, limit switches, etc.) also warrant attention for operational failures or performance degradation. Furthermore, internal leakage, particularly due to worn sealing surfaces or aging seals, also warrants special attention. Therefore, real-time monitoring and timely diagnosis of the health of each on-off valve component, identifying potential failures and providing early warnings, is crucial for ensuring safe system operation and normal process production.

[0004] Currently, fault diagnosis engineering practices for pneumatic on-off valves rely on two methods: a DCS system can perform simple fault diagnosis of the entire valve failing to operate based on the on / off control commands issued and the valve position feedback switch status signals; and a manual inspection system. However, the former method cannot determine the specific component failing to operate or the performance degradation of each component. Furthermore, manual inspection methods are limited by technical experience and on-site observation conditions, making it difficult to detect faults, prone to omissions, and delayed.

[0005] Chinese patent publication number CN112393015A discloses a method and apparatus for monitoring the health of a solenoid valve. The patent proposes a solenoid valve health monitoring method based on a pressure sensor and a position sensor. This method assesses the function and health of the solenoid valve by monitoring the pressure in the downstream pipeline at the solenoid valve outlet and the position changes of the solenoid valve core. While this solution can monitor the solenoid valve's status, it is limited to evaluating the solenoid valve's health and ignores fault diagnosis of other key components connected to the solenoid valve (such as the cylinder, valve, limit switch, and control air circuit). This approach fails to monitor the entire valve (including the cylinder, valve, limit switch, and control air circuit) and cannot provide a detailed conclusion on the fault location of the pneumatic valve. Furthermore, the improvements in this solution are more complex than those of conventional solenoid valves and alter conventional design specifications, such as the configuration and selection of electrical instruments in the original automatic control system, making them difficult for design institutes and users to accept. Summary of the Invention

[0006] The purpose of the present invention is to provide an online fault diagnosis system for pneumatic switch valves, which can perform overall fault diagnosis on pneumatic switch valves, provide detailed conclusions on the fault location, and meet the safety requirements in advanced intelligent production.

[0007] In order to achieve the above objectives, the technical solutions provided by the present invention are specifically as follows:

[0008] An online fault diagnosis system for a pneumatic switch valve, the system comprising:

[0009] An air pressure detection module, used to obtain an air pressure parameter P of the pneumatic actuator;

[0010] A valve opening detection module is used to obtain the displacement information of the valve stem in the pneumatic actuator and generate the valve opening parameter ZT accordingly;

[0011] An electrical signal acquisition module, used to obtain an electrical signal parameter D of the solenoid valve;

[0012] An instruction control module, used for transmitting an operating voltage signal of the master controller and sending a diagnostic test instruction to a test switch;

[0013] A setting module is used to perform setting operations and generate diagnostic test instructions; a parameter diagnosis basis is generated based on various parameters obtained during the setting operation;

[0014] The analysis module is used to receive the air pressure parameter P, valve opening parameter ZT and signal parameter D in the diagnosis operation, and obtain detailed fault information of the pneumatic switch valve based on comparative analysis of the parameter diagnosis basis.

[0015] As a preferred embodiment of the present invention, the setting operation is specifically: performing a full-stroke action test of the pneumatic switch valve and obtaining first time information, generating second time information based on the first time information and a preset cutting value; performing a partial-stroke action test of the pneumatic switch valve based on the second time information.

[0016] As a preferred embodiment of the present invention, the setting module is also used to generate a fault mapping table based on the parameter diagnosis basis; the fault mapping table is used to compare the air pressure parameter P, valve opening parameter ZT and electrical signal parameter D received by the analysis module during the diagnosis process.

[0017] As a preferred embodiment of the present invention, the system further includes an acoustic wave acquisition module, which is used to obtain ultrasonic parameters US at the valve; the setting module is used to generate a fault mapping table based on the parameter diagnosis, and the fault mapping table is used to compare the ultrasonic parameters US received by the analysis module during leak detection.

[0018] As a preferred embodiment of the present invention, when the parameter diagnosis basis is converted into the fault mapping table, an uncertainty threshold is added.

[0019] As a preferred embodiment of the present invention, the diagnostic operations include PST partial stroke action test diagnosis, FST full stroke action monitoring diagnosis and status monitoring.

[0020] As a preferred embodiment of the present invention, the detailed fault information includes various performance degradation information of the entire valve and its components, refusal to operate information, malfunction information, power failure information and air loss information.

[0021] As a preferred embodiment of the present invention, the triggering mode in which the instruction control module receives a trigger and sends a diagnostic test instruction to the test switch includes: triggering by a main control module, triggering by hardware, and triggering by a program timing.

[0022] As a preferred embodiment of the present invention, the pneumatic switch valve online fault diagnosis system further includes a communication module arranged between the analysis module and the general control module.

[0023] On the other hand, the present invention also provides a method for online fault diagnosis of a pneumatic switch valve, the method comprising:

[0024] S01, the setting module performs a setting operation and generates a diagnostic test instruction, and sends the diagnostic test instruction to the instruction control module for storage; and generates a parameter diagnosis basis based on various parameters obtained during the setting operation;

[0025] S02, executing a diagnostic operation, the instruction control module receives a trigger and sends a diagnostic test instruction to the test switch;

[0026] S03. The analysis module receives the air pressure parameter P, the valve opening parameter ZT and the electrical signal parameter D in the diagnosis operation, and obtains detailed fault information of the pneumatic switch valve based on comparative analysis of the parameter diagnosis basis.

[0027] As a preferred embodiment of the present invention, S01 specifically includes the steps of:

[0028] S011, the setting module controls the pneumatic switch valve to perform full stroke action test and obtain the first time information;

[0029] S012. Generate second time information based on the first time information and a preset segmentation value;

[0030] S013, generating a diagnostic test instruction based on the second time information, and using the diagnostic test instruction to control the pneumatic switch valve to perform a partial stroke test;

[0031] S014. Generate a parameter diagnosis basis based on various parameters obtained during the full-stroke actuation test and the partial-stroke actuation test.

[0032] On the other hand, the present invention also provides a pneumatic switching valve, comprising a valve, a main control module, a limit switch, a solenoid valve pneumatic actuator and the above-mentioned pneumatic switching valve online fault diagnosis system; the valve, main control module, limit switch, solenoid valve and pneumatic actuator are all connected to the pneumatic switching valve online fault diagnosis system.

[0033] In summary, the present invention has the following beneficial effects:

[0034] 1. This invention achieves comprehensive fault diagnosis for pneumatic switch valves without changing the structure and connection of the existing pneumatic switch valves and master control module. This pneumatic switch valve online fault diagnosis system does not change the conventional design specifications for the pneumatic switch valves and supporting control system, such as the configuration and selection of electrical instruments, making it more acceptable to design institutes and users.

[0035] 2. By setting up an air pressure detection module, a valve opening detection module, an electrical signal acquisition module, and an acoustic wave acquisition module, overall parameter intervention is performed on the three core components of the pneumatic switch valve: the pneumatic actuator, the valve, and the solenoid valve. This can realize fault diagnosis in PST test diagnosis, FST monitoring diagnosis, or status monitoring modes, and is therefore suitable for pneumatic switch valve diagnosis work in various application scenarios.

[0036] 3. The detailed fault information ultimately obtained by this pneumatic switch valve online fault diagnosis system includes various types of information for each component, enabling diagnosis of multiple valve fault types. This overcomes the deficiency of existing technologies that can only diagnose faults of some components. In the application practice of intelligent equipment, it has high practical value.

[0037] 4. The online fault diagnosis instrument implemented based on this system has achieved complete innovation in structure and function, realizing the true fault diagnosis and predictive maintenance of pneumatic switch valves.

[0038] 5. The setting of this system does not interfere with the normal operation of the original electrical control circuit (solenoid valve open-loop control of pneumatic switching valve, valve positioner closed-loop control), and realizes online monitoring and fault diagnosis.

[0039] 6. When using the online fault diagnosis instrument manufactured based on this system, the design of the original pneumatic switch valve (such as the selection and configuration of electrical accessories) does not need to be changed. There are no new sensors that are difficult to accept under engineering conditions. It is not only suitable for new production lines, but also particularly suitable for technical upgrades and renovations of existing pneumatic switch valve production lines.

[0040] 7. The online fault diagnosis instrument manufactured based on this system can completely replace manual inspections, and its functions cover comprehensive online diagnosis of major faults of pneumatic switch valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the system block diagram of the pneumatic switch valve online fault diagnosis system;

[0042] Figure 2 A schematic diagram of one system structure of the online fault diagnosis system in the embodiment;

[0043] Figure 3 A combined connection diagram of the online fault diagnosis system and the original pneumatic switch valve device in the embodiment;

[0044] Figure 4 This is a hardware structure diagram of one of the online fault diagnosis systems in the embodiment;

[0045] Figure 5 This is a flow chart of the online fault diagnosis method for the pneumatic switch valve. DETAILED DESCRIPTION

[0046] The following explains and illustrates the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and are not exhaustive. For example, various configurations of different pneumatic switch valves, such as various types of solenoid valves, actuators, limit switches, and various air circuit designs, are provided. Based on the embodiments described in the embodiments, other embodiments derived by those skilled in the art without inventive effort are also within the scope of protection of the present invention.

[0047] Throughout this specification, the claims, and the accompanying drawings, the terms "first," "second," and so forth are used to distinguish between different items, not to describe a particular order. Furthermore, the term "comprises" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules is not limited to the listed steps or modules but may optionally include steps or modules not listed, or may include other steps or modules inherent to the process, method, product, or apparatus.

[0048] The master control module is a digital control module used for industrial automation. It can be implemented based on existing automation control technologies such as DCS (Distributed Control System) or PLC. For example, it can use an operating voltage signal to energize or de-energize the solenoid valve coil (connecting or disconnecting the operating voltage signal through an internal control switch), thereby indirectly controlling the movement of the pneumatic actuator. This involves regulating the air pressure in the pneumatic actuator's cylinder, causing the piston and valve stem in the cylinder to drive the pneumatic switch valve to open or close. The limit switch is internally equipped with an open position switch and a closed position switch, which can identify the extreme movable positions of the valve stem. For example, when the valve stem triggers the open position switch, the limit switch outputs a feedback signal to the control module, allowing the control module to correctly identify the current valve position of the switch valve.

[0049] The pneumatic switch valve online fault diagnosis system provided by the present invention can realize the overall fault diagnosis of the pneumatic switch valve without changing the structure and connection mode of the original pneumatic switch valve and the main control module.

[0050] In one possible implementation, Figure 1As shown, this pneumatic on-off valve online fault diagnosis system is simultaneously connected to the main control module, limit switch, solenoid valve, and pneumatic actuator. This system includes an air pressure detection module. Taking a double-acting cylinder as an example, by installing a gas pressure gauge on the gas pipeline connecting the two air chambers, the air pressure parameter P can be obtained. The air pressure parameter P includes the pressure in each chamber, and its value can serve as the basis for subsequent fault diagnosis. The valve opening detection module is used to obtain displacement information of the valve stem in the pneumatic actuator (one end of the valve stem is connected to the piston head in the cylinder, and the other end is connected to the movable part of the valve). This can be achieved using a slide potentiometer, photoelectric sensor, or other means. For example, by acquiring and converting the electrical signal from the slide potentiometer, the valve stem position and displacement distance can be directly obtained. The valve opening detection module generates the valve opening parameter ZT based on this electrical signal. The electrical signal acquisition module is used to obtain the electrical signal parameter D of the solenoid valve. The electrical signal parameter D includes various characteristic signals, such as the current I flowing through the solenoid valve coil, the voltage U across the coil, and the coil resistance.

[0051] In another possible implementation, which is different from the above embodiment, Figure 2 As shown, the system also includes an acoustic wave acquisition module, which collects ultrasonic parameters US at the valve. This is achieved by continuously receiving ultrasonic waves through an ultrasonic sensor. Specifically, if a leak occurs at the target location, the jet of the leaked material (gas or liquid) will cause gas turbulence. The abnormal high-frequency ultrasonic signal generated by the turbulence is received by the ultrasonic sensor and used to determine valve leakage information, which is then used for subsequent tuning operations and fault analysis.

[0052] The command control module is used to transmit the operating voltage signal from the main control module and send diagnostic test instructions to the test switch. In this embodiment, the main control module supplies power to the solenoid valve coil through two positive and negative paths to achieve voltage control of the solenoid valve. In addition, a test switch is provided in one of the paths. If the test switch is closed, it does not affect the transmission of the operating voltage signal from the main control module, and the pneumatic switch valve fully opens or closes under the voltage control of the main control module. If the test switch is disconnected, the solenoid valve coil loses power, and the solenoid valve controls the piston and valve stem in the cylinder to perform partial stroke movement. The specific movement time of the piston and valve stem is the same as the time when the test switch is disconnected. This allows the pneumatic switch valve to perform partial stroke movement during the time when the test switch is disconnected.

[0053] The tuning module is used to perform tuning operations and generate diagnostic test instructions, as well as generate parameter diagnosis basis based on various parameters obtained during the tuning operation.

[0054] The following embodiment provides a specific tuning operation method. The tuning operation can be considered as first performing an FST full-stroke test, followed by a PST partial-stroke test, with the diagnostic parameter basis obtained based on both stroke tests. Specifically, the tuning module controls the test switch to close for a relatively long time (this time can be preset by the main control module, so that the length is greater than the time required for the pneumatic switch valve to complete a full-stroke movement). Then, first time information is obtained. The first time information can be derived based on feedback from a limit switch or other existing sensor-based displacement timing feedback of mechanical components such as pneumatic actuators or valves. This information represents the length of time it takes for the pneumatic switch valve equipped with the online fault diagnosis system to complete a full-stroke FST test. The tuning module then generates second time information based on the first time information and a preset split value. The preset split value can be manually preset or issued by the main control module. This split value is used as a percentage to divide the first time information into the second time information, which corresponds to the length of time the test switch is open during the subsequent PST partial-stroke test.

[0055] The setting module will generate a diagnostic test instruction based on the second time information. The diagnostic test instruction includes key time length information, which is used to indicate the duration of the disconnection of the test switch.

[0056] In one possible embodiment, when the preset split value is set to 0.15, the valve stroke time in the PST partial stroke test is 15% of the time length used in the FST full stroke test.

[0057] The tuning module also generates a fault mapping table based on the parameter diagnostic basis. This parameter diagnostic basis is a set of parameters collected by the various detection / acquisition modules during the stroke test of the pneumatic on / off valve during the tuning operation. This includes, but is not limited to, air pressure parameters P, valve opening parameters ZT, electrical signal parameters D, and ultrasonic parameters US.

[0058] In one possible embodiment, during the tuning operation, the parameter set obtained based on the stroke test can be preprocessed and entered into a preset fault information sheet to form a fault mapping table. The fault mapping table records detailed information about the pneumatic switch valve fault corresponding to different parameter result combinations. This information may indicate the component where the fault occurred and the type of fault. In particular, separate fault mapping tables can be generated for the FST full-stroke test and the PST partial-stroke test during the tuning operation. The fault mapping table can be stored in the memory hardware device where the tuning module or analysis module resides.

[0059] In one possible embodiment, the tuning module adds an uncertainty threshold to the parameter diagnostic base during the conversion of the parameter diagnostic base into a fault mapping table. This uncertainty threshold allows each parameter point in the parameter diagnostic base to be defined within a defined range. When the fault mapping table is subsequently used for analysis and comparison, the parameters collected during the diagnostic operation are considered successfully mapped as long as they fall within this range. The addition of the uncertainty threshold ensures that the method is applicable to actual fault diagnosis of pneumatic on / off valves of various types, uses, and operating environments. The value can be preset by engineers based on actual conditions or independently set by the master control module based on database information. The uncertainty threshold is particularly suitable for generating fault mapping tables for PST partial stroke tests.

[0060] In another possible embodiment, the setting operation of the setting module and the acquisition of the fault mapping table are obtained through offline or manual testing experiments.

[0061] The analysis module receives the air pressure parameter P, valve opening parameter ZT, and electrical signal parameter D during the diagnostic operation and, based on the parameter diagnosis foundation, performs comparative analysis to obtain detailed fault information for the pneumatic on / off valve. Specifically, the analysis module maps and analyzes the air pressure parameter P, valve opening parameter ZT, and electrical signal parameter D during the diagnostic operation based on a fault mapping table generated by the parameter diagnosis foundation, and outputs detailed fault information. The tuning module and analysis module can be implemented using a CPU processor and corresponding software programs.

[0062] The diagnostic operations in the present invention include PST partial stroke test diagnosis, FST full stroke monitoring diagnosis, and status monitoring. The PST partial stroke test diagnosis is primarily responsible for online fault diagnosis of pneumatic switch valves that have been inactive for extended periods of time, such as emergency shut-off valves, emergency isolation valves, emergency discharge valves, or emergency vent valves, which perform safety functions. By performing partial stroke test actions, the reliability of these pneumatic switch valves can be verified, and it can be determined whether these pneumatic switch valves have safety hazards such as refusal to operate. The FST full stroke monitoring diagnosis is primarily responsible for monitoring fault diagnosis of pneumatic switch valves that frequently operate, and can make timely performance degradation predictions based on detailed fault information. Status monitoring is a continuous monitoring operation that can continuously collect parameter information from each detection / acquisition module when not in the PST test diagnosis or FST monitoring diagnosis state, enabling timely feedback on pneumatic switch valve malfunctions and air source monitoring.

[0063] The following examples will explain in detail the process principle of the PST partial stroke test diagnostic operation. Figure 3As shown, a pneumatic actuator equipped with a double-acting cylinder is used as an example. The pneumatic actuator in this embodiment is equipped with a linear valve stem. Those skilled in the art will appreciate that other types of pneumatic actuators and mechanical combinations of valve stems and valves (such as rotary closing valves and linear closing valves) can also be implemented using the technical solutions provided by the present invention. In this embodiment, when the valve stem moves to the leftmost OFF position of the limit switch, it triggers the OFF switch, which then provides feedback to the DCS / PLC master control module. This indicates that the pneumatic switch valve connected to the valve stem is in a fully closed state. Similarly, the fully open position can be identified. The left and right air chambers of the double-acting cylinder are connected to solenoid valves, which control the air source path to achieve changes in the movement direction and position of the piston and valve stem in the cylinder. The specific operation of the solenoid valve is achieved by the control voltage across the solenoid valve coil. In this embodiment, a detection switch is provided along the path from the DCS / PLC master control module outputting a 24V voltage to the solenoid valve coil. When not performing PST diagnostic testing, the detection switch is closed.

[0064] Based on the setting operations described in the previous embodiments, a fault mapping table corresponding to the PST partial stroke test is obtained before performing the PST partial stroke test diagnosis. During the PST partial stroke test diagnosis, the command control module receives a trigger and sends a diagnostic test command to the test switch. The test switch receives the diagnostic test command, parses the time length information contained in the command, and performs a post-opening delayed closing operation, where the delay duration is the same as the second time information. After the test switch is opened, the solenoid valve coil loses power. The solenoid valve then controls the valve stem in the pneumatic actuator to perform partial stroke movement. The movement starts at any limit position (fully open or fully closed) and ends at the end position corresponding to the time the test switch is reclosed. During this process, the analysis module receives the air pressure parameter P, the valve opening parameter ZT, and the electrical signal parameter D, and enters each parameter into the acquired fault mapping table corresponding to the PST partial stroke test, performs a comparative analysis, and outputs detailed fault information.

[0065] In another possible embodiment, the process principle of FST full-stroke action monitoring and diagnosis is explained. Unlike the above embodiment, the command control module is not triggered, so that the test switch does not perform the disconnection operation. The solenoid valve operates normally under the control of the 24V voltage output by the DCS / PLC main control module, performing continuous and coherent full-open and full-close actions. At this time, the analysis module receives the air pressure parameter P, the valve opening parameter ZT, and the electrical signal parameter D, and brings each parameter into the fault mapping table corresponding to the obtained FST full-stroke test, performs comparative analysis, and outputs detailed fault information. The information stored in the fault mapping table corresponding to the FST full-stroke test includes fixed-point information of multiple valves at the fully open / fully closed position, such as the air pressure at the air source when the valve is fully open / fully closed, the valve limit opening, and the stable coil current value of the solenoid valve coil.

[0066] Different from the fault details information in the above embodiment, since the monitored pneumatic switch valve is in normal working condition, the information mainly contains the potential performance degradation information of each component, such as the improper movement of the valve stem, valve and other moving parts, or the aging of the solenoid valve coil causing abnormal response of the electrical signal.

[0067] In another possible embodiment, the process principle of state monitoring is explained. Unlike the above two embodiments, the state monitoring is mainly aimed at some pneumatic switch valves that are in a silent state for a long time. When the target pneumatic switch valve does not perform the PST partial stroke action test diagnosis and is not in a continuous action state, the instruction control module is also not triggered. The analysis module continuously receives the air pressure parameter P, the valve opening parameter ZT and the electrical signal parameter D, and brings each parameter into a specific fault mapping table. The fault mapping table can be converted from the fault mapping table corresponding to the above PST or FST, or it can be directly borrowed. It mainly monitors the sudden change of the electrical signal parameter D and the obviously abnormal air pressure parameter P. If the pneumatic switch valve has an abnormal state mutation, for example, the air source pressure is lower than the lower limit, the analysis module will promptly output the fault details information to the DCS / PLC main control module for alarm.

[0068] In a possible embodiment, the fault details include performance degradation information, refusal to operate information, malfunction information, power failure information, gas failure information, etc. of each component. Figure 3For example, if the coil current I collected during the PST test and diagnosis process successfully compares and analyzes with the fault mapping table, but the corresponding left air chamber pressure PA or right air chamber pressure PB fails to compare and analyze with the fault mapping table, the fault details can be output as pneumatic actuator refusal to operate. If the coil current I collected during the FST monitoring and diagnosis process fails to compare and analyze with the fault mapping table, the fault details can be output as solenoid valve refusal to operate. If the voltage U collected during the status monitoring process fails to compare and analyze with the fault mapping table (for example, voltage U is not equal to 24V or 0V), the fault details can be output as power supply anomaly. The above are merely examples of embodiments and do not limit the specific fault mapping method used in the technical solution of the present invention.

[0069] In a possible embodiment, the fault details include valve leakage information, and the analysis module is used to obtain ultrasonic parameters US during the leak detection process. Valve leakage may be caused by various factors, such as internal leakage of the valve seat caused by wear and cavitation of the valve core and valve seat, external leakage caused by aging and deformation of the valve cover packing or flange seal, etc. When gas or liquid leaks, gas turbulence will occur at the leak point, and the turbulence will form a high-frequency ultrasonic signal (usually with a frequency > 20kHz, which is beyond the hearing range of the human ear). Figure 3 and Figure 4 As shown, an ultrasonic sensor is installed at the valve. Leak detection is preferably performed with the valve fully closed (characteristic signals are clearer and more stable). The ultrasonic sensor captures these signals and converts them into digital signals that can be processed by the analysis module. The analysis module then calculates them (perhaps through noise reduction preprocessing and characteristic signal extraction techniques known in the art) and compares and analyzes them with the basic background acoustic wave parameters in the acquired fault mapping table to determine the final leakage information. During the pre-set operation, when generating the parameter diagnosis basis, the acoustic wave acquisition module collects two ultrasonic parameters US when the valve is in the fully open / fully closed state. Under normal circumstances, i.e., when there is no leakage, these two ultrasonic parameters US represent the basic background noise of the valve in the fully open / fully closed state (note that the basic background noise varies between the fully open and fully closed states). Based on these two ultrasonic parameters US, a parameter diagnosis basis is generated, and then a fault mapping table is generated based on this parameter diagnosis basis. For another example, when the valve is in the fully closed position, the analysis module can determine and generate valve leakage information based on the collected ultrasonic parameters US, and perform subtraction and threshold comparison between the ultrasonic parameters US obtained during the leak detection process and the parameter benchmark in the fault mapping table to generate corresponding valve leakage information.

[0070] In one possible embodiment, Figure 1 and Figure 4As shown, a communication unit is installed between the analysis module and the master control module. This unit can transmit feedback from the analysis unit and commands and data from the master control module via analog current signals or digital signals. Wireless communication is also possible. For example, the communication unit is used to transmit both analog current and digital signals in parallel. The 4-20mA analog current signal can convey valve position and fault information, while the HART digital signal can transmit a digital fault code (one for each fault type) detailing the fault, as well as commands from the master control module.

[0071] In addition, if Figure 4 As shown, a hardware implementation of the online fault diagnosis system is provided, wherein a CPU is connected to an A / D converter, which is used to convert analog signals obtained by each detection sensor into digital signals that can be operated by the CPU; the analysis module and the setting module can be arranged in the CPU, and a memory unit is also connected to the CPU, which can be used to store / temporarily store fault mapping tables or commands issued by the main control module; the communication unit is specifically composed of an EMC circuit, a HART modulation decoder + 4-20mA current loop, an internal power supply circuit, and a D / A converter + HART communication device, which is used to realize the parallel transmission of analog current signals and HART digital signals.

[0072] In one possible embodiment, the triggering methods for the instruction control module to receive a trigger and send a diagnostic test instruction to the test switch include: main control module triggering, hardware triggering, and program timing triggering. The main control module triggering method refers to the trigger command being directly issued by the main control module to the instruction control module, which can come from a manual or program-preset command of the DCS / PLC, and is applicable to PST partial stroke actuation test diagnosis under the integrated management mode; hardware triggering refers to a manual triggering through hardware such as a PST button, causing the instruction control module to send a diagnostic test instruction to the test switch and perform a PST partial stroke actuation test diagnosis, which is applicable to targeted diagnosis during manual inspections; program timing triggering refers to the automatic and timed triggering of the instruction control module by a timing program, and is applicable to routine, regular, automated PST partial stroke actuation test diagnosis.

[0073] In addition, if Figure 5 As shown, the present invention also provides a pneumatic switch valve online fault diagnosis method, which is applicable to the pneumatic switch valve online fault diagnosis system proposed in the present invention. The method includes:

[0074] S01, the setting module performs the setting operation and generates a diagnostic test instruction, and sends the diagnostic test instruction to the instruction control module for storage; and generates a parameter diagnosis basis based on various parameters obtained during the setting operation;

[0075] S011, the setting module controls the pneumatic switch valve to perform full stroke action test and obtain the first time information;

[0076] S012. Generate second time information based on the first time information and a preset segmentation value;

[0077] S013, generating a diagnostic test instruction based on the second time information, and using the diagnostic test instruction to control the pneumatic switch valve to perform a partial stroke actuation test;

[0078] S014. Generate a parameter diagnosis basis based on various parameters obtained during the full-stroke actuation test and the partial-stroke actuation test.

[0079] S02, executing the diagnostic operation, the instruction control module receives the trigger and sends a diagnostic test instruction to the test switch;

[0080] S03. The analysis module receives the air pressure parameter P, the valve opening parameter ZT and the signal parameter D in the diagnosis operation, and obtains detailed fault information of the pneumatic switch valve based on comparative analysis based on parameter diagnosis.

[0081] In addition, the present invention also provides a pneumatic switching valve, which includes a valve, a main control module, a limit switch, a solenoid valve pneumatic actuator and a pneumatic switching valve online fault diagnosis system as described in the above embodiment; the valve, main control module, limit switch, solenoid valve and pneumatic actuator are all connected to the pneumatic switching valve online fault diagnosis system.

[0082] It should be emphasized that the integration relationship between the online fault diagnosis system proposed in the present invention and the actual hardware of components such as solenoid valves and limit switches is not limited by the above-mentioned embodiments. Any technical solution for integrating the online fault diagnosis system with components such as solenoid valves and limit switches, as well as the solution for integrating the analysis module function into the host computer or platform, falls within the scope of protection involved in this disclosure.

[0083] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the module embodiments described above are merely illustrative. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules, modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interface, and the indirect coupling or communication connection of the device or module can be electrical or other forms.

[0084] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected to achieve the purpose of the present embodiment according to actual needs.

[0085] In addition, the functional modules in the various embodiments of the present application may be integrated into a processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The above-mentioned integrated modules may be implemented in the form of hardware or software functional modules.

[0086] The above description is merely a description of the preferred embodiments disclosed in this application and the technical principles employed. Those skilled in the art should understand that the scope of protection provided by this disclosure is not limited to technical solutions formed by a specific combination of the aforementioned technical features, but also encompasses other technical solutions formed by any combination of the aforementioned technical features or their equivalents without departing from the scope of the disclosure. For example, a technical solution formed by replacing the aforementioned features with (but not limited to) technical features with similar functions disclosed in this disclosure.

Claims

1. An online fault diagnosis system for pneumatic switch valves, characterized in that: The system includes: Air pressure detection module, used to obtain the air pressure parameter P of the pneumatic actuator; The valve opening detection module is used to obtain the displacement information of the valve stem in the pneumatic actuator and generate the valve opening parameter ZT accordingly; An electrical signal acquisition module, used to obtain the electrical signal parameter D of the solenoid valve; The command control module is used to transmit the operating voltage signal of the main control module and send diagnostic test instructions to the test switch; the command control module receives triggers and sends diagnostic test instructions to the test switch. The triggering methods include: main control module triggering, hardware triggering, and program timing triggering; A setting module is used to perform setting operations and generate diagnostic test instructions; a parameter diagnosis basis is generated based on various parameters obtained during the setting operation; An analysis module is used to receive the air pressure parameter P, the valve opening parameter ZT and the signal parameter D in the diagnosis operation, and obtain detailed fault information of the pneumatic switch valve based on comparative analysis of the parameter diagnosis basis; The fault details include performance degradation information of the entire valve and its components, refusal to operate information, malfunction information, power failure information and air loss information.

2. The pneumatic switch valve online fault diagnosis system according to claim 1 is characterized in that: The adjustment operation is specifically as follows: performing a full-stroke action test of the pneumatic switch valve and obtaining first time information, generating second time information based on the first time information and a preset cutoff value; and performing a partial-stroke action test of the pneumatic switch valve based on the second time information.

3. The pneumatic switch valve online fault diagnosis system according to claim 1, characterized in that: The setting module is further used to generate a fault mapping table based on the parameter diagnosis basis; the fault mapping table is used to compare the air pressure parameter P, valve opening parameter ZT and electrical signal parameter D received by the analysis module during the diagnosis process.

4. The pneumatic switch valve online fault diagnosis system according to claim 1, characterized in that: The system also includes an acoustic wave acquisition module, which is used to obtain ultrasonic parameters US at the valve; the setting module is used to generate a fault mapping table based on the parameter diagnosis, and the fault mapping table is used to compare the ultrasonic parameters US received by the analysis module during leak detection.

5. The pneumatic switch valve online fault diagnosis system according to claim 3, characterized in that: When the parameter diagnosis basis is converted into the fault mapping table, an uncertainty threshold is added.

6. The pneumatic switch valve online fault diagnosis system according to claim 1, characterized in that: The diagnostic operations include PST partial stroke test diagnosis, FST full stroke motion monitoring diagnosis and status monitoring.

7. The pneumatic switch valve online fault diagnosis system according to claim 1, characterized in that: The pneumatic switch valve online fault diagnosis system further comprises a communication module arranged between the analysis module and the main control module.

8. A pneumatic switch valve online fault diagnosis method based on the pneumatic switch valve online fault diagnosis system according to claim 1, characterized in that: The method includes: S01, the setting module performs a setting operation and generates a diagnostic test instruction, and sends the diagnostic test instruction to the instruction control module for storage; and generates a parameter diagnosis basis based on various parameters obtained during the setting operation; S02, executing a diagnostic operation, the instruction control module receives a trigger and sends a diagnostic test instruction to the test switch; S03. The analysis module receives the air pressure parameter P, the valve opening parameter ZT and the electrical signal parameter D in the diagnosis operation, and obtains detailed fault information of the pneumatic switch valve based on comparative analysis of the parameter diagnosis basis.

9. The method for online fault diagnosis of a pneumatic switch valve according to claim 8, characterized in that: S01 specifically includes the following steps: S011, the setting module controls the pneumatic switch valve to perform full stroke action test and obtain the first time information; S012. Generate second time information based on the first time information and a preset segmentation value; S013, generating a diagnostic test instruction based on the second time information, and using the diagnostic test instruction to control the pneumatic switch valve to perform a partial stroke test; S014. Generate a parameter diagnosis basis based on various parameters obtained during the full-stroke actuation test and the partial-stroke actuation test.

10. A pneumatic switch valve, characterized in that: It comprises a valve, a main control module, a limit switch, a solenoid valve, a pneumatic actuator and an online fault diagnosis system for a pneumatic switch valve as described in any one of claims 1 to 7; the valve, the main control module, the limit switch, the solenoid valve and the pneumatic actuator are all connected to the online fault diagnosis system for a pneumatic switch valve.

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