Pneumatic switch valve online fault diagnosis system and diagnosis method

Abstract

The invention particularly relates to an online fault diagnosis system and method for a pneumatic switch valve. The system comprises an air pressure detection module for acquiring an air pressure parameter P of the pneumatic actuating mechanism; the valve opening detection module is used for acquiring a valve opening parameter ZT; the electric signal acquisition module is used for acquiring an electric signal parameter D of the electromagnetic valve; the control module is used for transmitting a working voltage signal of the master controller and sending a diagnosis test instruction to the test switch; the setting module is used for executing setting operation, generating a diagnosis test instruction and generating a parameter diagnosis basis based on each parameter obtained in the setting operation process; and the analysis module is used for receiving each parameter in the diagnosis operation and obtaining fault detail information of the pneumatic switch valve based on parameter diagnosis basis comparative analysis. The system can comprehensively diagnose the faults of the whole pneumatic switch valve and each component, and meets the safety requirements of advanced intelligent production.

Description

Technical Field

[0001] The present invention relates to the technical field of on-off valve equipment, and particularly to an online fault diagnosis system and diagnosis method for pneumatic on-off valves. Background Art

[0002] In process industries such as oil refining, petrochemical, chemical, electric power, metallurgy, paper making, pharmaceutical, and light industry, pneumatic on-off valves are used for the action execution of controlling the on-off and direction switching of process media (liquids, gases, mixtures). Its main body and control system mainly consist of the following parts: valves (ball valves, butterfly valves, gate valves, globe valves, etc.), pneumatic actuators (cylinders, pistons, diaphragms, fork levers) for pushing the valves to open and close, solenoid valves for controlling the pneumatic actuators, limit switches for judging the piston movement position, and a master controller for controlling the solenoid valve action. The reliability and precise control performance of pneumatic on-off valves are crucial for the safety and stability of equipment.

[0003] During long-term operation, pneumatic on-off valves may be affected by factors such as mechanical action wear, medium corrosion, and temperature and pressure environment aging, resulting in failures of their various components, especially the core components such as solenoid valves, cylinders, and valves, or performance degradation. These failures may cause the valve to fail to correctly respond to the instructions of the master controller or have a response delay, further leading to equipment shutdown or even production accidents. For example, some emergency shut-off valves, emergency isolation valves, emergency discharge valves, or emergency vent valves responsible for performing safety functions are normally in a non-operating state for a long time. When an emergency occurs, it is necessary to pay attention to whether they can act according to the control requirements and whether there will be a refusal to act; for another example, for some frequently operating on-off valves, it is also necessary to pay attention to whether there are operating failures or performance degradation problems in their various components (solenoid valves / cylinders / valves / control air circuits / limit switches, etc.); for another example, internal leakage that is most likely to occur due to wear of the sealing surface or aging of the sealing parts of the valve also needs special attention. Therefore, real-time monitoring and timely diagnosis of the health status of each component of the on-off valve, timely discovery of potential failures and early warning are crucial for ensuring the safe operation of the system and normal process production.

[0004] Currently, in the engineering practice of fault diagnosis of pneumatic on-off valves, on the one hand, the DCS end can make a simple judgment on the whole valve refusal-to-act fault based on the issued switch control instruction and the valve position feedback switch status signal; on the other hand, it relies on manual inspection. However, in the former case, it is impossible to judge which specific component refuses to act and more detailed fault details such as performance degradation of each component; while in the latter case of manual inspection, it is limited by technical experience and on-site observation conditions, making it difficult to discover faults, and it is easy to miss and be untimely.

[0005] A Chinese patent document with the publication number CN112393015A discloses a method and device for monitoring the health of a solenoid valve, which proposes a method for monitoring the health of a solenoid valve based on a pressure sensor and a position sensor. This method evaluates the function and health status of the solenoid valve by monitoring the downstream pipeline pressure at the outlet of the solenoid valve and the position change of the solenoid valve core. Although this solution can monitor the state of the solenoid valve, it is limited to the health assessment of the solenoid valve and ignores the fault diagnosis of other key components connected to the solenoid valve (such as cylinders, valves, limit switches, and control air circuits). It is impossible to achieve overall monitoring of the on-off valve (including cylinders, valves, limit switches, and control air circuits, etc.), and it is impossible to give a detailed conclusion on the fault location of the pneumatic on-off valve. In addition, compared with conventional solenoid valves, the improvement in the above solution has a more complex structural design and changes the conventional design specifications such as the electrical instrument configuration selection of the original automatic control system, making it difficult for design institutes and users to accept. Summary of the Invention

[0006] The object of the present invention is to provide an online fault diagnosis system for a pneumatic on-off valve, which can perform overall fault diagnosis on the pneumatic on-off valve, give a detailed conclusion on the fault location, and meet the safety requirements in advanced intelligent production.

[0007] To achieve the above object, the technical solution provided by the present invention is specifically as follows: An online fault diagnosis system for a pneumatic on-off valve, the system includes: A pressure detection module for obtaining the air pressure parameter P of the pneumatic actuator; A valve opening detection module for obtaining the displacement information of the valve stem in the pneumatic actuator and correspondingly generating a valve opening parameter ZT; An electrical signal acquisition module for obtaining the electrical signal parameter D of the solenoid valve; An instruction control module for transmitting the working voltage signal of the total controller and sending a diagnostic test instruction to the test switch; A tuning module for performing a tuning operation and generating a diagnostic test instruction; generating a parameter diagnosis basis based on the parameters obtained during the tuning operation; An analysis module for receiving the air pressure parameter P, the valve opening parameter ZT, and the signal parameter D in the diagnostic operation, and comparing and analyzing based on the parameter diagnosis basis to obtain the detailed fault information of the pneumatic on-off valve.

[0008] As a preference of the present invention, the tuning operation is specifically: performing a full stroke action test on the pneumatic on-off valve and obtaining the first time information, generating the second time information based on the first time information and a preset cut-off value; performing a partial stroke action test on the pneumatic on-off valve based on the second time information.

[0009] Preferably, the setting module is further configured 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, the valve opening parameter ZT, and the electrical signal parameter D received by the analysis module during the diagnosis process.

[0010] Preferably, the system further includes an acoustic wave acquisition module, and the acoustic wave acquisition module is configured to obtain the ultrasonic parameter US at the valve; the setting module is configured to generate a fault mapping table based on the parameter diagnosis basis, and the fault mapping table is used to compare the ultrasonic parameter US received by the analysis module during the leak detection operation.

[0011] Preferably, when the parameter diagnosis basis is converted into the fault mapping table, an uncertainty threshold is added.

[0012] Preferably, the diagnostic operation PST includes partial stroke action test diagnosis, FST full stroke action monitoring diagnosis, and status monitoring.

[0013] Preferably, the fault detail information includes various performance degradation information, rejection information, misoperation information, power loss information, and air loss information of the entire valve and each component.

[0014] Preferably, the triggering methods by which the instruction control module accepts the trigger and sends a diagnostic test instruction to the test switch include: total control module trigger, hardware trigger, and program timing trigger.

[0015] Preferably, this kind of pneumatic switch valve online fault diagnosis system further includes a communication module arranged between the analysis module and the total control module.

[0016] On the other hand, the present invention also provides a method for online fault diagnosis of a pneumatic switch valve, and 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 the parameters obtained during the setting operation; S02. Perform a diagnostic operation, and the instruction control module accepts the 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 diagnostic operation, and obtains the fault detail information of the pneumatic switch valve by comparing and analyzing based on the parameter diagnosis basis.

[0017] Preferably, in S01, it specifically includes the steps: S011. The setting module controls the pneumatic switch valve to perform a full stroke action test and obtains the first time information; S012. Generate second time information based on the first time information and a preset cut-off value; S013. Generate a diagnostic test instruction based on the second time information, and use the diagnostic test instruction to control the pneumatic switch valve to perform a partial stroke action test; S014. Generate a parameter diagnosis basis based on the parameters obtained during the full stroke action test and the partial stroke action test.

[0018] On the other hand, the present invention also provides a pneumatic switch valve, which includes a valve, a total control module, a limit switch, a solenoid valve pneumatic actuator, and the above-mentioned on-line fault diagnosis system for pneumatic switch valves; the valve, the total control module, the limit switch, the solenoid valve, and the pneumatic actuator are all connected to the on-line fault diagnosis system for pneumatic switch valves.

[0019] In summary, the present invention has the following beneficial effects: 1. The present invention realizes the overall fault diagnosis of the pneumatic switch valve without changing the structure and connection mode of the original pneumatic switch valve and the total control module. The on-line fault diagnosis system for pneumatic switch valves does not change the conventional design specifications such as the electrical instrument configuration selection of the original pneumatic switch valve and the supporting control system, making it more acceptable to design institutes and users.

[0020] 2. By setting a pressure detection module, a valve opening detection module, an electrical signal acquisition module, and a sound wave acquisition module, and intervening in the overall parameters of the three core components of the pneumatic switch valve: the pneumatic actuator, the valve, and the solenoid valve, it is possible to realize fault diagnosis in modes such as PST test diagnosis, FST monitoring diagnosis, or status monitoring, and thus be applicable to the diagnosis of pneumatic switch valves in a variety of different application scenarios.

[0021] 3. The final fault detail information obtained by the on-line fault diagnosis system for pneumatic switch valves includes various types of information of each component, realizing the diagnosis of various valve fault types, overcoming the deficiency in the prior art that only partial components can be fault diagnosed, and having high practical value in the application practice of intelligent devices.

[0022] 4. The on-line fault diagnosis instrument implemented based on this system is completely innovative in structure and function, realizing the true fault diagnosis and predictive maintenance of the pneumatic switch valve.

[0023] 5. The setting of this system does not interfere with the normal operation of the original electrical control loop (the open-loop control of the solenoid valve of the pneumatic switch valve and the closed-loop control of the valve positioner), and realizes on-line monitoring and fault diagnosis.

[0024] 6. When the on - line fault diagnosis instrument manufactured based on this system is applied, it does not change the original design of the pneumatic switch valve (such as the selection and configuration of electrical accessories), and there are no newly added sensors that are difficult to accept under engineering conditions. It is not only applicable to newly built production lines, but especially suitable for the technical upgrading and transformation of existing production lines with pneumatic switch valves.

[0025] 7. The on - line fault diagnosis instrument manufactured based on this system can completely replace manual inspection tours, and its functions cover the comprehensive on - line diagnosis of the main faults of pneumatic switch valves. Description of the Drawings

[0026] Figure 1 It is the system block diagram of this on - line fault diagnosis system for pneumatic switch valves; Figure 2 It is one of the schematic diagrams of the system structure of this on - line fault diagnosis system in the embodiment; Figure 3 It is a combined connection diagram of this on - line fault diagnosis system and the original pneumatic switch valve device in the embodiment; Figure 4 It is one of the hardware structure diagrams of this on - line fault diagnosis system in the embodiment; Figure 5 It is the flow chart of the on - line fault diagnosis method for this pneumatic switch valve. Detailed Embodiments

[0027] Next, the technical solutions of the embodiments of the present invention will be explained and described in conjunction with the drawings of the embodiments of the present invention. However, the following embodiments are only the preferred embodiments of the present invention and not all of them, such as various configurations of different pneumatic switch valves including various types of solenoid valves, actuators, limit switches, and various gas circuit designs. Based on the embodiments in the implementation manners, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0028] The terms "first", "second", etc. in the description, claims, and the above - mentioned drawings of this specification are used to distinguish different objects, rather than to describe a specific order. In addition, the term "including" and any of its variations are intended to cover non - exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the listed steps or modules, but may optionally further include steps or modules not listed, or may optionally further include other steps or modules inherent to these processes, methods, products, or devices.

[0029] The total control module is a digital control module for industrial automation control, which can be implemented based on automation control technologies such as DCS (Distributed Control System) or PLC in the prior art. For example, it can control the energization or de-energization of the solenoid valve coil through a working voltage signal (by an internal control switch to achieve the connection or disconnection of the working voltage signal), and then indirectly control the operation of the pneumatic actuator, that is, adjust the air pressure in the cylinder of the pneumatic actuator, so that the piston and valve stem in the cylinder drive the valve of the pneumatic switch valve to perform opening / closing actions. The limit switch is internally provided with an open-in-place switch and a close-in-place switch, which can identify the extreme movement position of the valve stem. For example, after the valve stem triggers the open-in-place switch, the limit switch will output a feedback signal to the control module, so that the control module can correctly identify the valve position state of the current switch valve.

[0030] The on-line fault diagnosis system for pneumatic switch valves provided by the present invention can achieve the overall fault diagnosis of pneumatic switch valves without changing the structure and connection mode of the original pneumatic switch valves and the total control module.

[0031] In a possible implementation manner, as Figure 1 shown, the on-line fault diagnosis system for this pneumatic switch valve is simultaneously connected to the total control module, the limit switch, the solenoid valve and the pneumatic actuator. This system includes a air pressure detection module. Taking a double-acting cylinder as an example, by setting a gas pressure gauge on the air pipeline connecting the two air chambers, the air pressure parameter P can be obtained. The air pressure parameter P includes the pressures of the two air chambers respectively, and the numerical value of its parameter can be used as the basis for subsequent fault judgment. The valve opening detection module is used to obtain the 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). Specifically, it can be realized by means such as a sliding potentiometer and an optoelectronic sensor. Taking the former as an example, by obtaining and converting the electrical signal of the sliding potentiometer, information such as the valve stem position and the displacement distance can be directly obtained. The valve opening detection module can generate a valve opening parameter ZT based on the above 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 types of characteristic signals, such as the current value I flowing through the solenoid valve coil, the voltage value U at both ends of the coil, and the coil resistance, etc.

[0032] In another possible implementation manner, which is different from the above embodiment, as Figure 2As shown in the figure, the system also includes an acoustic wave acquisition module, which is used to acquire the ultrasonic parameter US at the valve and can be realized by continuously receiving ultrasonic waves through an ultrasonic sensor. Specifically, if a leak occurs at the target location, the jet of the leaked substance (gas or liquid) will cause gas turbulence. The abnormal high-frequency ultrasonic signal formed by the turbulence is received by the ultrasonic sensor and used to judge the valve leakage information for subsequent tuning operations and fault analysis.

[0033] The instruction control module is used to transmit the working voltage signal of the total control module and send a diagnostic test instruction to the test switch. In this embodiment, the total control module supplies power to the solenoid valve coil through two positive and negative paths to achieve voltage control of the solenoid valve. And a test switch is set in one of the paths. If it is closed, it does not affect the transmission of the working voltage signal of the total control module. The valve of the pneumatic switch valve performs full-open or full-close actions under the voltage control of the total control module. If it is disconnected, the solenoid valve coil loses power, and the solenoid valve will control the piston and valve stem in the cylinder to perform a partial stroke movement. Specifically, the movement time of the piston and valve stem is the same as the time when the test switch is disconnected, which makes the valve of the pneumatic switch valve perform a partial stroke action during the time when the test switch is disconnected.

[0034] The tuning module is used to perform tuning operations and generate diagnostic test instructions, and generate a parameter diagnosis basis based on the parameters obtained during the tuning operation.

[0035] The following embodiment provides a specific tuning operation method. The tuning operation can be regarded as first performing an FST full stroke test and then performing a PST partial stroke test, and obtaining a parameter diagnosis basis based on the two stroke tests. Specifically, the tuning module controls the test switch to close for a relatively long time (this time can be preset by the command of the total control module, and its time length is greater than the time length required for the pneumatic switch valve to perform a full stroke action). Then, the first time information is obtained. The first time information can be obtained according to the feedback information of the limit switch or the displacement timing feedback of other existing sensors on mechanical components such as the pneumatic actuator or the valve, and it is used to represent the time length required for the pneumatic switch valve equipped with this online fault diagnosis system to perform an FST full stroke test. Then, the tuning module can generate the second time information according to the first time information and the preset cut-off value. The preset cut-off value can be preset manually or issued by the total control module. As a percentage, it is used to divide the first time information to generate the second time information, and the second time information corresponds to the time length when the test switch is disconnected for the subsequent PST partial stroke test.

[0036] The tuning module will generate a diagnostic test instruction according to the second time information. The diagnostic test instruction contains the key time length information, which is used to indicate the duration when the test switch is disconnected.

[0037] In one possible embodiment, when the preset cut-off value is set to 0.15, in the PST partial stroke test, the stroke action time of the valve is 15% of the time length used in the FST full stroke test.

[0038] In addition, the tuning module is further configured to generate a fault mapping table based on the parameter diagnosis basis. The parameter diagnosis basis is a set of parameters collected by each detection / collection module during the stroke test of the pneumatic switch valve in the tuning operation, and it includes, but is not limited to, the air pressure parameter P, the valve opening parameter ZT, the electrical signal parameter D, the ultrasonic parameter US, etc.

[0039] In one possible embodiment, during the tuning operation, the set of parameters obtained based on the stroke test can be preprocessed and filled into a preset fault information form to form a fault mapping table. The fault mapping table records the detailed fault information of the pneumatic switch valve corresponding to different parameter result combinations, and this information can indicate the components where the fault occurs and the fault type, etc. Specifically, for the FST full stroke test and the PST partial stroke test during the tuning operation, respective fault mapping tables can be formed. The fault mapping table can be stored in the memory hardware device where the tuning module or the analysis module is located.

[0040] In one possible embodiment, during the process of the tuning module converting the parameter diagnosis basis into a fault mapping table, an uncertainty threshold is further added to the parameter diagnosis basis. The uncertainty threshold can make each parameter point in the parameter diagnosis basis become a definite range value. When the subsequent fault mapping table is used for analysis and comparison, as long as each parameter collected during the diagnosis operation falls within the above range, it can be considered that the mapping is successful. The addition of the uncertainty threshold is to make this method applicable to the actual fault diagnosis of pneumatic switch valves of various types, uses, and working environments. Its value can be preset by the engineer according to the actual situation, or automatically set by the total control module according to the database information. The uncertainty threshold is particularly applicable to the formation of the fault mapping table corresponding to the PST partial stroke test.

[0041] In another possible embodiment, the tuning operation of the tuning module and the obtaining of the fault mapping table are obtained through offline or manual testing experiments.

[0042] The analysis module is configured to receive the air pressure parameter P, the valve opening parameter ZT, and the electrical signal parameter D in the diagnosis operation, and obtain the detailed fault information of the pneumatic switch valve through comparative analysis based on the parameter diagnosis basis. Specifically, the analysis module performs mapping analysis on the air pressure parameter P, the valve opening parameter ZT, and the electrical signal parameter D in the diagnosis operation based on the fault mapping table formed by the parameter diagnosis basis, and outputs the detailed fault information. The tuning module and the analysis module can be implemented based on a CPU processor and the corresponding software program.

[0043] The diagnostic operations in the present invention include PST partial stroke action test diagnosis, FST full stroke action monitoring diagnosis, and status monitoring. Among them, the PST partial stroke action test diagnosis is mainly responsible for the online fault diagnosis of pneumatic on-off valves such as emergency shut-off valves, emergency isolation valves, emergency discharge valves, or emergency vent valves that perform safety functions and are in a state of not operating for a long time. Through the test action of the partial stroke, it verifies the reliability of the above-mentioned types of pneumatic on-off valves and can determine whether there are safety hazards such as refusal to act in the above-mentioned types of pneumatic on-off valves; the FST full stroke action monitoring diagnosis is mainly responsible for the monitoring fault diagnosis of pneumatic on-off valves that often operate and can make a performance degradation prediction in a timely manner according to the fault detail information; the status monitoring is a continuous monitoring operation that can continuously collect the parameter information of each detection / collection module in the state of non-PST test diagnosis and non-FST monitoring diagnosis to achieve timely feedback on actions such as misoperation of pneumatic on-off valves and air source monitoring.

[0044] The following embodiments will elaborate in detail on the process principle of the PST partial stroke action test diagnosis operation. As Figure 3 shown, taking a pneumatic actuator equipped with a double-acting cylinder as an example, the pneumatic actuator in this embodiment is equipped with a straight valve stem. Those skilled in the art should be familiar that other types of pneumatic actuators and the mechanical combination forms of valve stems and valves (such as rotary closing valves, linear closing valves, etc.) can also be realized by the technical solutions provided by the present invention. In this embodiment, it can be known that when the valve stem moves to the leftmost OFF position of the limit switch, it will trigger the OFF switch, and then the limit switch will feedback to the DCS / PLC master control module. At this time, it indicates that the valve of the pneumatic on-off valve connected to the valve stem is in a fully closed state; vice versa, its fully open position can be identified. The left and right air chambers of the double-acting cylinder are respectively connected to the solenoid valves, and the solenoid valves control the air source path to achieve the change of the movement direction and position of the piston and valve stem in the cylinder; the specific action of the solenoid valve is realized by the control voltage at both ends of the solenoid valve coil. In this embodiment, a detection switch is provided on the path where the DCS / PLC master control module outputs 24V voltage to the solenoid valve coil. When the PST test diagnosis is not performed, the detection switch is in a closed state.

[0045] Based on the setting operation described in the previous embodiment, before performing the PST partial stroke action test diagnosis, a fault mapping table corresponding to the PST partial stroke test has been obtained. When performing the PST partial stroke action test diagnosis, the instruction control module receives the trigger and sends a diagnostic test instruction to the test switch; the test switch receives the diagnostic test instruction and parses the time length information carried in the diagnostic test instruction, and performs a disconnection and then delayed closing operation, and the delay duration is the same as the second time information. After the test switch is disconnected, the solenoid valve coil loses power, and at this time the solenoid valve will control the valve stem in the pneumatic actuator to perform a partial stroke movement, the starting point of the movement is any one of the extreme positions (fully open position or fully closed position), and the end point of the movement is the cut-off position corresponding to the time point when the test switch is re-closed. During the above process, the analysis module receives the air pressure parameter P, the valve opening parameter ZT, and the electrical signal parameter D, and substitutes each parameter into the fault mapping table corresponding to the PST partial stroke test that has been obtained, and conducts a comparative analysis to output the fault detail information.

[0046] In another possible embodiment, the process principle of the FST full stroke action monitoring diagnosis is described. Different from the above embodiment, the instruction control module is not triggered, so that the test switch does not perform the disconnection operation, and the solenoid valve works normally under the control of the 24V voltage output by the DCS / PLC total control module, and performs continuous and coherent fully open and fully closed 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 substitutes each parameter into the fault mapping table corresponding to the FST full stroke test that has been obtained, and conducts a comparative analysis to output the fault detail information. The information stored in the fault mapping table corresponding to the FST full stroke test includes the fixed point information of multiple valves at the fully open / fully closed positions, such as the air pressure at the air source when the valve is fully open / fully closed, the limit opening of the valve, the stable coil current value of the solenoid valve coil, etc.

[0047] Different from the fault detail information in the above embodiment, since the monitored pneumatic switch valve is in a normal working state, the main content included in the information is the potential performance degradation information of each component, such as the movement of the valve stem, the valve and other moving parts not in place, or the coil aging reflected by the abnormal reaction of the electrical signal of the solenoid valve coil.

[0048] In another possible embodiment, the process principle of status monitoring is described. Different from the above two embodiments, the status monitoring mainly targets 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 command control module is not triggered either. The analysis module continuously receives the air pressure parameter P, the valve opening parameter ZT, and the electrical signal parameter D, and substitutes each parameter into a specific fault mapping table. This fault mapping table can be transformed from the fault mapping table corresponding to the above PST or FST, or can be directly borrowed. It mainly monitors the mutated electrical signal parameter D and the significantly abnormal air pressure parameter P. If an abnormal status mutation occurs in the pneumatic switch valve, such as the air source pressure being lower than the lower limit, the analysis module will promptly output the fault detail information to the DCS / PLC master control module for alarm.

[0049] In a possible embodiment, the fault detail information includes the performance degradation information, refusal to act information, misoperation information, power loss information, air loss information, etc. of each component. Taking Figure 3 a pneumatic actuator equipped with a double-acting cylinder as an example, if the coil current I collected during the PST test diagnosis is successfully compared and analyzed with the fault mapping table, but the corresponding left air chamber pressure PA or right air chamber pressure PB fails to be compared and analyzed with the fault mapping table, the fault detail information of refusal to act of the pneumatic actuator can be output; if the coil current I collected during the FST monitoring diagnosis fails to be compared and analyzed with the fault mapping table, the fault detail information of refusal to act of the solenoid valve can be output; if the voltage U collected during the status monitoring fails to be compared and analyzed with the fault mapping table (for example, the voltage U is not equal to 24V or 0V), the fault detail information of abnormal power supply can be output. The above are only example embodiments and do not limit the specific fault mapping table mapping method in the technical solution of the present invention.

[0050] In a possible embodiment, the fault detail information includes the leakage information of the valve. The analysis module is used to obtain the ultrasonic parameter US during the leak detection work. 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 leakage occurs, a gas turbulence phenomenon will occur at the leakage point, and the turbulence will form a high-frequency ultrasonic signal (usually with a frequency > 20kHz, beyond the audible range of the human ear). As Figure 3 and Figure 4As shown, an ultrasonic sensor is provided at the valve. The leak detection work is preferably carried out when the valve is fully closed (the characteristic signal is clearer and more stable). The ultrasonic sensor captures these signals and converts them into digital signals that can be processed by the analysis module. After being calculated by the analysis module (through means such as noise reduction preprocessing and characteristic signal extraction in the prior art), it is then compared and analyzed with the basic background acoustic wave parameters in the obtained fault mapping table, so as to determine the final leakage information. When generating the parameter diagnosis basis during the previous tuning operation, the acoustic wave acquisition module acquires two ultrasonic parameters US when the valve is in the fully open / fully closed state. Under normal circumstances, that is, when there is no leakage, the above two ultrasonic parameters US represent the basic background noise at the valve in the fully open / fully closed state (it should be noted that the basic background noise is different in the fully open / fully closed state). Based on the above 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 generate and obtain the valve leakage information based on the acquired ultrasonic parameter US. The ultrasonic parameter US obtained during the leak detection process is compared with the parameter reference in the fault mapping table by taking the difference and comparing with the threshold to correspondingly generate the leakage information of the valve.

[0051] In a possible embodiment, as Figure 1 and Figure 4 shown, a communication unit is provided between the analysis module and the total control module. The communication unit can transmit the feedback information sent by the analysis unit and the commands and data sent by the total control module through analog current signals or digital signals; it can also be implemented in the form of wireless communication. Taking the parallel transmission of analog current signals and digital signals as an example, the communication unit is used to achieve the parallel transmission of analog current signals and hart digital signals. Among them, the 4~20mA analog current signal can transmit the valve position and the indication information of whether there is a fault, and the hart digital signal can transmit the digital fault code representing the detailed fault information (each fault category corresponds to a digital fault code) and the commands of the total control module, etc.

[0052] In addition, as Figure 4 shown, a hardware implementation form of this online fault diagnosis system is provided, where the CPU is connected to the A / D converter. The A / D converter is used to convert the analog signals obtained by each detection sensor into digital signals that can be operated by the CPU; the analysis module and the tuning module can be arranged in the CPU, and there is also a memory unit connected to the CPU, which can be used to store / temporarily store the fault mapping table or the commands sent by the total 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 conversion + hart communication device, and is used to achieve the parallel transmission of analog current signals and hart digital signals.

[0053] In a possible embodiment, the triggering methods by which the instruction control module accepts a trigger and sends a diagnostic test instruction to the test switch include: master control module trigger, hardware trigger, and program timing trigger. The master control module trigger means that the trigger command is directly sent by the master control module to the instruction control module, which can come from manual or program preset commands of the DCS / PLC, and is applicable to the PST partial stroke action test diagnosis in the integrated management mode; the hardware trigger means that through hardware forms such as the PST button, it is manually pressed to trigger, so that the instruction control module sends a diagnostic test instruction to the test switch and performs a PST partial stroke action test diagnosis, which is applicable to targeted diagnosis during manual inspection; the program timing trigger means that the instruction control module is automatically triggered at regular intervals by a timing program, which is applicable to the daily regular automated PST partial stroke action test diagnosis.

[0054] In addition, as Figure 5 shown, the present invention also provides an on-line fault diagnosis method for a pneumatic switch valve, which is applicable to the on-line fault diagnosis system for a pneumatic switch valve proposed by the present invention. The method includes: S01. The tuning module performs a tuning 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 the parameters obtained during the tuning operation; S011. The tuning module controls the pneumatic switch valve to perform a full stroke action test and obtains the first time information; S012. Generates second time information based on the first time information and a preset cut-off value; S013. Generates a diagnostic test instruction based on the second time information, and uses the diagnostic test instruction to control the pneumatic switch valve to perform a partial stroke action test; S014. Generates a parameter diagnosis basis based on the parameters obtained during the full stroke action test and the partial stroke action test.

[0055] S02. Perform a diagnostic operation, the instruction control module accepts 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 signal parameter D in the diagnostic operation, and obtains the fault detail information of the pneumatic switch valve through comparative analysis based on the parameter diagnosis basis.

[0056] In addition, the present invention also provides a pneumatic switch valve, which includes a valve, a master control module, a limit switch, a solenoid valve pneumatic actuator, and an on-line fault diagnosis system for a pneumatic switch valve as described in the above embodiment; the valve, the master control module, the limit switch, the solenoid valve, and the pneumatic actuator are all connected to the on-line fault diagnosis system for a pneumatic switch valve.

[0057] It should be emphasized that the integration relationship between the online fault diagnosis system proposed by the present invention and the actual hardware of components such as solenoid valves and limit switches is not limited by the above embodiments. Any technical solution for integrating this online fault diagnosis system with components such as solenoid valves and limit switches, as well as the solution for integrating the functions of the analysis module into the host computer or platform, falls within the protection scope involved in this disclosure.

[0058] In several embodiments provided in this application, it should be understood that the disclosed device can be implemented in other ways. For example, the module embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division. In actual implementation, there may be other division methods. For example, 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 displayed or discussed coupling or direct coupling or communication connection to each other can be through some service interfaces. The indirect coupling or communication connection of the device or module can be in an electrical or other form.

[0059] The modules described as separate components may or may not be physically separated. The components shown as modules may or may not be physical modules, that is, they can be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0060] In addition, in each embodiment of this application, the various functional modules can be integrated in a processing module, or each module can exist physically alone, or two or more modules can be integrated in one module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0061] As described above, it is only the preferred embodiment disclosed in this application and the explanation of the applied technical principles. Those skilled in the art should understand that the protection scope involved in this disclosure is not limited to the technical solution formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the technical solution formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in this disclosure.

Claims

1. An online fault diagnosis system for a pneumatic switch valve, characterized in that: System includes: An air pressure detection module, used to obtain an air pressure parameter P of the pneumatic actuator; A valve opening detection module is used to obtain the displacement information of the valve stem in the pneumatic actuator and generate a valve opening parameter ZT accordingly; An electrical signal acquisition module, used to obtain an electrical signal parameter D of the solenoid valve; A command control module, used to transmit the working voltage signal of the main control module and send a diagnostic test command to the test switch; A setting module, used to perform setting operations and generate diagnostic test instructions; generate parameter diagnosis basis based on various parameters obtained during the setting operation; The 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 the fault detailed information of the pneumatic switch valve based on the parameter diagnosis comparison and analysis.

2. The pneumatic switch valve online fault diagnosis system according to claim 1 is characterized in that: The setting operation is specifically: executing 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 segmentation value; and executing 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 is characterized in that: 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.

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

7. The pneumatic switch valve online fault diagnosis system according to claim 1 is characterized in that: The fault details information includes performance degradation information, refusal to operate information, malfunction information, power failure information and air failure information of the entire valve and each component.

8. The pneumatic switch valve online fault diagnosis system according to claim 1 is characterized in that: The triggering modes in which the instruction control module receives a trigger and sends a diagnostic test instruction to the test switch include: a main control module trigger, a hardware trigger, and a program timing trigger.

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

10. A method for online fault diagnosis of a pneumatic switch valve, 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 the fault detailed information of the pneumatic switch valve based on the parameter diagnosis comparison and analysis.

11. The method for online fault diagnosis of a pneumatic switch valve according to claim 10, characterized in that: S01 specifically includes the following steps: S011, the setting module controls the pneumatic switch valve to perform a full-stroke action test and obtain the first-time information; S012, generating 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 action test; S014. Generate a parameter diagnosis basis based on various parameters obtained during the full-stroke action test and the partial-stroke action test.

12. 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 9; 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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