Integrated valve pneumatic actuating mechanism and fault diagnosis method

Abstract

The invention discloses an integrated valve pneumatic actuating mechanism which is used for being installed on a valve body to conduct fault diagnosis on a valve and comprises a gas driving unit, a support unit, a displacement sensor unit, an I / P conversion unit, a control unit, a connecting rod unit and a displacement feedback unit. The invention further discloses a fault diagnosis method based on the integrated valve pneumatic actuator. The valve position control function and the valve fault diagnosis function are integrated, a mounting support needed by an existing split type scheme is omitted, the mounting and debugging process before the pneumatic valve is put into production is greatly simplified, the clamping stagnation fault existing in the valve is detected losslessly and efficiently, the influence of the fault on normal operation of the valve is reduced through control compensation, and the working efficiency of the pneumatic valve is improved. And the material cost, the labor cost and the time cost of installation and debugging are greatly reduced. And a metal pipeline in the integrated valve pneumatic actuating mechanism not only is compact in structure, but also enhances the environmental adaptability and stability of the pneumatic valve.

Description

Technical Field

[0001] The invention belongs to the field of pneumatic valves, and in particular relates to an integrated valve pneumatic actuator and a fault diagnosis method. Background Art

[0002] The valve pneumatic actuator is based on pneumatic control technology and uses compressed gas as the driving force. When the compressed gas enters the cylinder, the piston will produce linear motion, thereby driving the mechanical parts to perform corresponding actions. The pneumatic actuator uses the intelligent valve positioner to control the flow and direction of the internal gas to achieve control of the linear displacement or angular displacement of the valve stem.

[0003] Currently, pneumatic actuators and smart valve positioners are generally split, that is, the smart valve positioner needs to be connected to the pneumatic actuator by bolts. Since the two usually come from different manufacturers, the shell shape and threaded hole position are different, the smart valve positioner will encounter problems such as difficult adjustment of the displacement feedback rod, small installation space and even shell interference during actual installation. This problem leads to a long installation and debugging time before the pneumatic valve is put into production, and even requires additional customized positioner mounting brackets, which greatly increases economic, time and labor costs. Summary of the invention

[0004] The purpose of the present invention is to solve the problems existing in the prior art and to provide an integrated valve pneumatic actuator and a fault diagnosis method.

[0005] The specific technical solutions adopted by the present invention are as follows:

[0006] In a first aspect, the present invention provides an integrated valve pneumatic actuator for installation on a valve body to perform fault diagnosis on the valve, which includes a gas drive unit, a bracket unit, a displacement sensor unit, an I / P conversion unit, a control unit, a connecting rod unit and a displacement feedback unit;

[0007] The displacement sensor unit, the I / P conversion unit and the control unit are installed in the internal space of the bracket unit; the displacement sensor unit and the I / P conversion unit are respectively connected to the control unit through circuits to achieve signal transmission and coordinated work;

[0008] The gas drive unit is installed on the bracket unit, and the bracket unit is provided with a first channel, a second channel and an exhaust channel; the I / P conversion unit is provided with a control chamber with three interfaces; the inlet of the first channel is located on the surface of the bracket unit, and is used to connect to an external gas source, and the outlet is connected to the first interface in the control chamber; the second channel connects the second interface in the control chamber with the gas chamber inlet of the gas drive unit; the inlet of the exhaust channel is connected to the third interface in the control chamber, and the outlet is located on the surface of the bracket unit, and is used to connect to the external atmosphere; the I / P conversion unit switches between the intake state and the exhaust state by opening and closing the three interfaces of the control chamber. In the intake state, the first channel and the second channel are connected through the control chamber, and in the exhaust state, the second channel and the exhaust channel are connected through the control chamber;

[0009] The connecting rod unit passes through the interior of the bracket unit, the upper end of the connecting rod unit is rigidly connected to the moving part of the gas drive unit, and the lower end of the connecting rod unit is rigidly connected to the valve stem of the valve body;

[0010] The displacement feedback unit is assembled on the connecting rod unit and moves synchronously with the connecting rod unit; during the synchronous movement of the displacement feedback unit, the connecting rod unit and the valve stem, the valve position measurement value signal is collected by the displacement sensor unit coordinated with the displacement feedback unit;

[0011] The control unit is used to send a control signal to the I / P conversion unit according to the valve position setting value, and change the gas pressure in the gas chamber in the gas drive unit by switching the intake state and the exhaust state, thereby driving the moving component to drive the valve stem to actuate, and the valve position measurement value signal collected by the displacement sensor unit is sent to the control unit, constituting feedback control of the valve stem stroke.

[0012] As a preferred embodiment of the first aspect, the gas drive unit is a linear gas drive unit or a rotary gas drive unit.

[0013] As a preferred embodiment of the first aspect, the gas drive unit is a single-acting gas drive unit having only one gas chamber therein, and the first channel and the second channel are each provided in the bracket unit.

[0014] As a preferred embodiment of the above-mentioned first aspect, the gas drive unit adopts a double-acting gas drive unit having two gas cavities with opposite driving directions inside, and a first channel and two second channels are arranged in the bracket unit, and the two second channels are respectively connected to the gas cavities with different driving directions.

[0015] As a preferred embodiment of the above-mentioned first aspect, the displacement sensor unit and the displacement feedback unit include two forms: non-contact type and contact type; if it is non-contact type, the displacement sensor unit adopts a Hall sensor, and the displacement feedback unit adopts a magnetic element, and the two are combined to achieve; if it is contact type, the displacement sensor unit adopts a transmission gear, and the displacement feedback unit adopts a potentiometer, and the two are combined to achieve.

[0016] As a preferred embodiment of the first aspect, the I / P conversion unit adopts a piezoelectric valve.

[0017] As a preferred embodiment of the first aspect, the gas drive unit and the bracket unit are integrally formed.

[0018] As a preferred embodiment of the first aspect, a pressure sensor electrically connected to the control unit is provided in the second channel for collecting the gas pressure value in the gas drive unit and transmitting it to the control unit.

[0019] In a second aspect, the present invention provides a fault diagnosis method using the integrated valve pneumatic actuator as described in any one of the first aspects above, comprising the following steps:

[0020] S1. Install the integrated valve pneumatic actuator on the valve to be diagnosed, and keep the lower end of the connecting rod unit rigidly connected to the valve stem of the valve to be diagnosed;

[0021] S2. The control unit in the integrated valve pneumatic actuator executes a diagnostic program, and by outputting a control signal to the I / P conversion unit, the gas drive unit drives the valve stem to actuate periodically, and in each actuation cycle, the valve position setting value uniformly increases from 0% to 100% and then uniformly decreases to 0% to perform an opening and closing process; during the periodic actuation of the valve stem, the valve position measurement value signal is collected by the displacement sensor unit, and the gas pressure signal in the gas drive unit is collected by the pressure sensor; then, the valve position setting value, valve position measurement value and gas pressure signal in a single valve stem actuation cycle are aligned in the time domain to generate a first variation curve of the valve position measurement value changing with the valve position setting value in one cycle, and a second variation curve of the gas pressure changing with the valve position setting value in one cycle;

[0022] S3. Mark the signal dead zone and all first jumps on the first change curve, and record the dead zone range S of the signal dead zone on the valve position setting value coordinate axis. d and the jump range S of each first jump on the valve position setting value coordinate axis en ; Mark all second jumps on the second change curve, and record the maximum value P of each second jump on the gas pressure coordinate axis en; The first jump on the first change curve and the second jump on the second change curve correspond one to one based on the valve position setting value, and the valve position setting value where each group of corresponding first jump and second jump are located at the same time is the jump valve position;

[0023] S4. For each jump valve position, calculate the viscosity coefficient c of each jump valve position n = / , and the sticking degree of each jump valve position is graded based on the viscosity coefficient;

[0024] S5. For each jump valve position, calculate the pressure target value P that the gas drive unit recommends outputting at the jump valve position during the next control. 输出 =P en / c n .

[0025] As a preferred embodiment of the above-mentioned second aspect, when grading the sticking degree of each jump valve position based on the viscosity coefficient, the viscosity coefficient in the range of 0 to 1 is divided into multiple levels according to a preset number of grades, wherein the smaller the viscosity coefficient, the higher the sticking degree, and the larger the viscosity coefficient, the lower the sticking degree.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention integrates the structure and function of the existing split-type pneumatic actuator and the intelligent positioner into one, eliminating the original installation bracket, greatly simplifying the installation and debugging process of the pneumatic valve before it is put into production, and can realize the automatic testing and intelligent diagnosis of the valve, non-destructively and efficiently detect the jamming fault in the valve, and reduce the impact of the fault on the normal operation of the valve through control compensation, greatly reducing the material, labor and time costs of installation and debugging.

[0028] (2) Existing pneumatic actuators and positioners are generally connected by external air pipes, which are usually exposed to the environment and easily damaged by human factors or environmental factors. The integrated valve pneumatic actuator provided by the present invention realizes the integration of internal gas pipelines, reduces the risk of gas leakage caused by aging, damage or joint damage of the air pipe between the positioner and the pneumatic actuator in the existing technical solutions, and enhances the environmental adaptability and stability of the pneumatic valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the front structure of the integrated valve pneumatic actuator provided in this embodiment installed on the valve body;

[0030] Figure 2 A side sectional view of the integrated valve pneumatic actuator provided in this embodiment;

[0031] Figure 3 A schematic diagram of the internal piping arrangement of the integrated valve pneumatic actuator provided in this embodiment;

[0032] Figure 4 A schematic diagram of the internal gas flow direction of the integrated valve pneumatic actuator provided in this embodiment when charging and discharging;

[0033] Figure 5 is a schematic diagram of a first change curve in an embodiment of the present invention;

[0034] Figure 6 is a schematic diagram of a second change curve in an embodiment of the present invention;

[0035] In the figure: drive unit 1, bracket unit 2, displacement sensor unit 3, I / P conversion unit 4, control unit 5, side cover 6, valve body 7, connecting rod unit 8, displacement feedback unit 9, second channel 10, first channel 11, exhaust channel 12. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0037] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0038] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the materials can be obtained from commercial sources unless otherwise specified; in the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection", "connection", and "installation" should be understood in a broad sense, for example, it can be fixed connection, setting, or detachable connection, setting, or integral connection, setting. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for the purpose of distinguishing descriptions, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0040] like Figure 1 and Figure 2As shown, in a preferred embodiment of the present invention, an integrated valve pneumatic actuator is provided, which is used to be installed on a valve body 7 to perform fault diagnosis on the valve, and includes a gas drive unit 1, a bracket unit 2, a displacement sensor unit 3, an I / P conversion unit 4, a control unit 5, a connecting rod unit 8 and a displacement feedback unit 9. Since the displacement sensor unit 3 and the I / P conversion unit 4 are respectively connected to the control unit 5 through circuits to realize signal transmission and coordinated work, the displacement sensor unit 3, the I / P conversion unit 4 and the control unit are packaged together, which reduces the number of external connection lines and reduces the risk of failure caused by poor connection. At the same time, the length of the signal transmission path can be reduced, thereby reducing the signal transmission delay and improving the response speed of the system. A wiring through hole is opened on the inner wall of the bracket unit 2 near the I / P conversion unit 4, which is convenient for connecting the internal unit components of the bracket unit 2 with the external power supply and the external signal processing mechanism. In order to facilitate the installation and maintenance of the displacement sensor unit 3, the I / P conversion unit 4 and the control unit 5, a side cover 6 is provided at the opening on one side of the bracket unit 2 in this embodiment, and the bracket unit 2 and the side cover 6 are detachably connected by bolts. In other embodiments, the side cover 6 and the bracket unit 2 may also be connected by a hinge or other means that facilitate the opening of the side cover 6. The bracket unit 2 and the side cover 6 surround a space of a certain volume, which is used to install the displacement sensor unit 3, the I / P conversion unit 4 and the control unit 5. In actual work, the side cover 6 is closed to protect the units in the space, which can effectively reduce the impact of the external environment (such as dust, humidity, electromagnetic interference, etc.) on the electronic components and improve the reliability and stability of the system.

[0041] In the embodiment of the present invention, the connecting rod unit 8 passes through the inside of the bracket unit 2, the upper end of the connecting rod unit 8 is rigidly connected to the moving part of the gas drive unit 1, the lower end of the connecting rod unit 8 is rigidly connected to the valve stem of the valve body 7, the displacement feedback unit 9 is assembled on the connecting rod unit 8 and moves synchronously with the connecting rod unit 8, the gas drive unit 1 drives the connecting rod unit 8 to move, and the connecting rod unit 8 drives the valve stem to move, and during the synchronous movement of the displacement feedback unit 9, the connecting rod unit 8 and the valve stem, the displacement sensor unit 3 matched with the displacement feedback unit 9 collects the valve position measurement value signal. The displacement feedback unit 9 can be rigidly connected to the connecting rod unit 8, or other suitable connection methods can be used, but it is necessary to ensure that the displacement feedback unit 9 can move synchronously with the valve stem. Among them, the displacement sensor unit 3 and the displacement feedback unit 9 include two forms: non-contact type and contact type; if it is non-contact type, the displacement sensor unit 3 adopts a Hall sensor, and the displacement feedback unit 9 adopts a magnetic element, and the two are combined to achieve; if it is contact type, the displacement sensor unit 3 adopts a transmission gear, and the displacement feedback unit 9 adopts a potentiometer, and the two are combined to achieve.

[0042] like Figure 1 and Figure 3 As shown, the gas drive unit 1 is mounted on the bracket unit 2, and the bracket unit 2 is provided with a first channel 11, a second channel 10 and an exhaust channel 12. A control chamber with three interfaces is provided in the I / P conversion unit 4, the inlet of the first channel 11 is located on the surface of the bracket unit 2, and is used to connect to an external gas source, and the outlet is connected to the first interface in the control chamber. The second channel 10 connects the second interface in the control chamber with the gas chamber inlet of the gas drive unit 1. The inlet of the exhaust channel 12 is connected to the third interface in the control chamber, and the outlet is located on the surface of the bracket unit 2, and is used to connect to the external atmosphere. The I / P conversion unit 4 switches between the intake state and the exhaust state by opening and closing the three interfaces of the control chamber. In the intake state, the first channel 11 and the second channel 10 are connected through the control chamber, and in the exhaust state, the second channel 10 and the exhaust channel 12 are connected through the control chamber. Therefore, the integral molding of the gas drive unit 1 and the bracket unit 2 can better ensure that the through-hole parts of the two have good air tightness. According to the specific application scenario, the gas drive unit 1 has a variety of implementation forms. For straight-stroke valves, diaphragm-type or piston-type linear gas drive units can be selected, and for angular-stroke valves, piston-type or gear rack-type rotary gas drive units can be selected. Single-acting gas drive units or double-acting gas drive units can also be selected according to needs. When the gas drive unit 1 adopts a single-acting gas drive unit with only one gas chamber inside, one first channel 11 and one second channel 10 are respectively provided inside the bracket unit 2; when the gas drive unit 1 adopts a double-acting gas drive unit with two gas chambers with opposite driving directions inside, one first channel 11 and two second channels 10 are provided inside the bracket unit 2, and the two second channels 10 are respectively connected to the gas chambers with different driving directions. This design realizes the integration of internal gas pipelines, reduces the risk of gas leakage caused by aging, damage or joint damage between the positioner and the pneumatic actuator in the existing technical solution, and enhances the environmental adaptability and stability of the pneumatic valve.

[0043] In a preferred embodiment provided by the present invention, the gas drive unit 1 adopts a single-acting diaphragm linear gas drive unit, the sensor in the displacement sensor unit 3 adopts a linear Hall sensor, and the displacement feedback unit 9 adopts a rectangular magnetic body whose magnetic flux density is linearly related to the displacement along the length direction within a certain range, and the magnetic body is rigidly connected to the connecting rod unit 8 by bolts. The control unit 5 sends a control signal to the I / P conversion unit 4 according to the valve position setting value, changes the air pressure of the gas chamber in the gas drive unit 1 by switching the intake state and the exhaust state, and then drives the moving parts of the gas drive unit 1 to drive the valve stem to move, and collects the valve stem stroke through the displacement feedback unit 9 and the displacement sensor unit 3. Since the valve stem stroke is positively correlated with the valve position measurement value, the valve stem stroke can be used as a valve position measurement value signal and sent to the control unit 5. The control signal is processed by the control unit 5 and then transmitted to the I / P conversion unit 4, and the feedback control of the valve stem stroke is formed through the I / P conversion unit 4. In this embodiment, the I / P conversion unit 4 adopts a piezoelectric valve. The piezoelectric valve is based on the inverse piezoelectric effect. The deformation of the piezoelectric ceramic under different voltages controls the flow of gas. The received control signal is converted into an air pressure signal, and the air pressure signal is transmitted to the gas drive unit 1 to control the pressure increase or decrease in the cylinder of the gas drive unit 1. When the pressure in the cylinder increases, the gas drive unit 1 drives the connecting rod unit 8 to move upward in a straight line, and when the pressure in the cylinder decreases, the connecting rod unit 8 is driven to move downward in a straight line, thereby changing the valve opening. In other embodiments, the I / P conversion unit may also use a nozzle baffle, a solenoid valve or other components that can convert electrical signals into air pressure signals.

[0044] In the embodiment provided by the present invention, pressure sensors electrically connected to the control unit 5 are provided in the first channel 11, the second channel 10 and the exhaust channel 12, for real-time monitoring and collecting the gas pressure value in the gas drive unit 1, and transmitting it to the control unit 5. The control unit 5 accurately controls the timing and amount of air intake and exhaust based on these data. During the air intake process, it prevents excessive air pressure from causing damage to the integrated valve pneumatic actuator due to overpressure; during the exhaust process, it prevents excessive air pressure from causing the system to malfunction due to negative pressure, thereby achieving accurate control of the valve opening and ensuring that the valve operates in the best state. The airflow direction of the above channels during inflation and exhaust is as follows: Figure 4 As shown, a is the inflation state, b is the exhaust state, and the arrow indicates the airflow direction.

[0045] On the other hand, the present invention also provides a fault diagnosis method based on the above-mentioned integrated valve pneumatic actuator, which mainly includes the following steps:

[0046] S1. Install the integrated valve pneumatic actuator on the valve to be diagnosed, and keep the lower end of the connecting rod unit 8 rigidly connected to the valve stem of the valve to be diagnosed;

[0047] S2. The control unit 5 in the integrated valve pneumatic actuator executes a diagnostic program, and by outputting a control signal to the I / P conversion unit 4, the gas drive unit 1 drives the valve stem to actuate periodically. In each actuation cycle, the valve position setting value uniformly increases from 0% to 100% and then uniformly decreases to 0% during the opening and closing process; during the periodic actuation of the valve stem, the valve position measurement value signal is collected by the displacement sensor unit 3, and the gas pressure signal in the gas drive unit 1 is collected by the pressure sensor; then the valve position setting value, valve position measurement value and gas pressure signal in a single valve stem actuation cycle are aligned in the time domain to generate a first change curve of the valve position measurement value changing with the valve position setting value in one cycle, and a second change curve of the gas pressure changing with the valve position setting value in one cycle.

[0048] In the present invention, the control unit 5 needs to achieve the control goal of the opening and closing process in which the valve position setting value increases uniformly from 0% to 100% and then decreases uniformly to 0%. Therefore, the control signal output to the I / P conversion unit 4 should be a ramp signal that first increases and then decreases. When the valve position setting value increases uniformly from 0% to 100%, the I / P conversion unit 4 is in the intake state, and when the valve position setting value decreases uniformly from 100% to 0%, the I / P conversion unit 4 is in the exhaust state.

[0049] It should be noted that the displacement sensor unit 3 directly senses the valve stem stroke signal provided by the displacement feedback unit 9 , but since the valve stem stroke corresponds to the actual valve position measurement value, the signal obtained by the displacement sensor unit 3 can be converted and mapped into the valve position measurement value.

[0050] In the embodiment provided by the present invention, when the integrated pneumatic actuator is installed on a linear control valve with a rated pressure of 0.3 MPa, the first variation curve is as follows: Figure 5 As shown, the horizontal axis is the valve position setting value, and the vertical axis is the valve position measurement value. The second change curve is as shown in Figure 6 As shown, the horizontal axis is the valve position measurement value and the vertical axis is the gas pressure.

[0051] S3. Mark the signal dead zone and all first jumps on the first change curve, and record the dead zone range S of the signal dead zone on the valve position setting value coordinate axis. d (i.e., the absolute difference between the two lateral endpoints of the signal dead zone on the valve position setting value coordinate axis) and the jump range S of each first jump on the valve position setting value coordinate axis en (i.e., the absolute difference between the two lateral endpoints of the jump point area on the valve position setting value coordinate axis); mark all second jumps on the second change curve, and record the maximum value P of each second jump on the gas pressure coordinate axis en(That is, the larger one of the coordinate values ​​of the two longitudinal endpoints of the jump point area on the gas pressure coordinate axis).

[0052] It should be noted that, according to the principle of signal jump, the first jump on the first change curve and the second jump on the second change curve must correspond one-to-one based on the valve position setting value, that is, each group of corresponding first jumps and second jumps are located at the same valve position setting value. In the present invention, the valve position setting value where each group of corresponding first jumps and second jumps are located at the same time is called the jump valve position.

[0053] In the embodiment of the present invention, the jump valve position in the curve is found by difference and threshold judgment; if there is a jump valve position on the curve, the dead zone range S on the first change curve is automatically identified. d , signal jump range S en ;by Figure 5 and Figure 6 For example, there are i jump valve positions, so the jump range of i jump valve positions is S en Marked as S e1 , S e2 , ..., S ei ; The maximum value P on the pressure coordinate axis of the second change curve en , if there are i jump valve positions, they are marked as P e1 , P e2 , ..., P ei The jump mark of the curve can identify the valve core stuck at multiple points, and further quantify the degree of sticking. d And signal jump range S en The calculated valve stem static friction factor is f d =(S d -S en ) / 2, the valve stem sliding friction factor is f s =(S d +S en ) / 2.

[0054] S4. For each jump valve position, calculate the viscosity coefficient c of each jump valve position n =(S d -S en ) / (S d +S en ), and the sticking degree of each jump valve position is graded based on the viscosity coefficient.

[0055] According to the static friction factor f d and the valve stem sliding friction factor f s Calculate c n =f d / f s =(Sd -S en ) / (S d +S en ), and the sticking degree is graded according to the obtained viscosity coefficient c: the viscosity coefficient in the range of 0 to 1 is divided into multiple levels according to a preset number of grades, wherein the smaller the viscosity coefficient, the higher the sticking degree, and the larger the viscosity coefficient, the lower the sticking degree. The grading of c and whether an alarm needs to be issued can be adjusted according to actual needs. In an embodiment of the present invention, it can be set that when c is (0, 0.33), the valve to be diagnosed is judged to be severely stuck and an alarm needs to be issued; when c is [0.33, 0.67), the valve to be diagnosed is judged to be moderately stuck, and an alarm still needs to be issued; when c is [0.67, 1), the valve to be diagnosed is judged to be slightly stuck, and no alarm needs to be issued; when c is 1, no sticking occurs, and no alarm is required.

[0056] S5. For each jump valve position, calculate the pressure target value P that the gas drive unit 1 recommends outputting at the jump valve position during the next control. 输出 =P en / c n .

[0057] Therefore, the next time the valve is controlled, when the valve stem moves to this jump valve position, the pressure target value P can be output in advance according to the recommended output pressure. 输出 Pressure control is performed using a ratio compared to the original P en The amplified gas pressure provides the driving force to overcome the valve stem sticking and reduce the valve sticking phenomenon.

[0058] Based on the above steps S1 to S5, the automatic detection of all jump valve positions in a cycle can be realized, and the corresponding stagnation degree classification labels and the quantitative value of the valve core stagnation force can also be obtained. Of course, in order to ensure accuracy in practical applications, P 输出 The pressure target value output by the gas drive unit 1 at the nth jump point during the next control is used as the pressure target value. By controlling the compensation and optimizing the control parameters, the influence of the fault on the normal operation of the valve is reduced, the valve is ensured to operate in the best state, the abnormal operation caused by the fault is reduced, and the service life of the valve is extended.

[0059] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. An integrated valve pneumatic actuator, used for being installed on a valve body (7) to perform fault diagnosis on the valve, characterized in that: It comprises a gas drive unit (1), a bracket unit (2), a displacement sensor unit (3), an I / P conversion unit (4), a control unit (5), a connecting rod unit (8) and a displacement feedback unit (9); The displacement sensor unit (3), the I / P conversion unit (4) and the control unit (5) are installed in the internal space of the bracket unit (2); the displacement sensor unit (3) and the I / P conversion unit (4) are respectively connected to the control unit (5) through circuits to achieve signal transmission and coordinated work; The gas drive unit (1) is mounted on a bracket unit (2), and a first channel (11), a second channel (10) and an exhaust channel (12) are provided inside the bracket unit (2); a control chamber having three interfaces is provided inside the I / P conversion unit (4); the inlet of the first channel (11) is located on the surface of the bracket unit (2) and is used to connect to an external gas source, and the outlet is connected to the first interface in the control chamber; the second channel (10) connects the second interface in the control chamber and the gas chamber inlet of the gas drive unit (1); the inlet of the exhaust channel (12) is connected to the third interface in the control chamber, and the outlet is located on the surface of the bracket unit (2) and is used to connect to the external atmosphere; the I / P conversion unit (4) switches between an intake state and an exhaust state by opening and closing the three interfaces of the control chamber; in the intake state, the first channel (11) and the second channel (10) are connected through the control chamber, and in the exhaust state, the second channel (10) and the exhaust channel (12) are connected through the control chamber; The connecting rod unit (8) passes through the interior of the bracket unit (2), the upper end of the connecting rod unit (8) is rigidly connected to the moving part of the gas drive unit (1), and the lower end of the connecting rod unit (8) is rigidly connected to the valve stem of the valve body (7); The displacement feedback unit (9) is mounted on the connecting rod unit (8) and moves synchronously with the connecting rod unit (8); during the synchronous movement of the displacement feedback unit (9), the connecting rod unit (8) and the valve stem, a valve position measurement value signal is collected by a displacement sensor unit (3) coordinated with the displacement feedback unit (9); The control unit (5) is used to send a control signal to the I / P conversion unit (4) according to the valve position setting value, and changes the gas pressure in the gas chamber of the gas drive unit (1) by switching the intake state and the exhaust state, thereby driving the moving component to drive the valve stem to move, and the valve position measurement value signal collected by the displacement sensor unit (3) is sent to the control unit (5), thereby forming feedback control of the valve stem stroke.

2. The integrated valve pneumatic actuator according to claim 1, characterized in that: The gas drive unit (1) is a linear gas drive unit or a rotary gas drive unit.

3. The integrated valve pneumatic actuator according to claim 1, characterized in that: The gas drive unit (1) is a single-acting gas drive unit having only one gas chamber inside, and the first channel (11) and the second channel (10) are each provided in the bracket unit (2).

4. The integrated valve pneumatic actuator according to claim 1, characterized in that: The gas drive unit (1) is a double-acting gas drive unit having two gas cavities with opposite driving directions inside, and a first channel (11) and two second channels (10) are arranged inside the bracket unit (2), and the two second channels (10) are respectively connected to the gas cavities with different driving directions.

5. The integrated valve pneumatic actuator according to claim 1, characterized in that: The displacement sensor unit (3) and the displacement feedback unit (9) include two types: non-contact type and contact type. If it is a non-contact type, the displacement sensor unit (3) uses a Hall sensor and the displacement feedback unit (9) uses a magnetic element, and the two are combined to achieve the desired effect. If it is a contact type, the displacement sensor unit (3) uses a transmission gear and the displacement feedback unit (9) uses a potentiometer, and the two are combined to achieve the desired effect.

6. The integrated valve pneumatic actuator according to claim 1, characterized in that: The I / P conversion unit (4) adopts a piezoelectric valve.

7. The integrated valve pneumatic actuator according to claim 1, characterized in that: The gas drive unit (1) and the bracket unit (2) are integrally formed.

8. The integrated valve pneumatic actuator according to claim 1, characterized in that: A pressure sensor electrically connected to the control unit (5) is provided in the second channel (10) and is used to collect the gas pressure value in the gas drive unit (1) and transmit it to the control unit (5).

9. A fault diagnosis method for an integrated valve pneumatic actuator according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, installing the integrated valve pneumatic actuator on the valve to be diagnosed, keeping the lower end of the connecting rod unit (8) rigidly connected to the valve stem of the valve to be diagnosed; S2, the control unit (5) in the integrated valve pneumatic actuator executes a diagnostic program, and by outputting a control signal to the I / P conversion unit (4), the gas drive unit (1) drives the valve stem to actuate periodically, and in each actuation cycle, the valve position setting value increases uniformly from 0% to 100% and then decreases uniformly to 0% to perform an opening and closing process; during the valve stem periodic actuation process, the valve position measurement value signal is collected by the displacement sensor unit (3), and the gas pressure signal in the gas drive unit (1) is collected by the pressure sensor; then, the valve position setting value, valve position measurement value and gas pressure signal in a single valve stem actuation cycle are aligned in the time domain to generate a first variation curve of the valve position measurement value changing with the valve position setting value in one cycle, and a second variation curve of the gas pressure changing with the valve position setting value in one cycle; S3. Mark the signal dead zone and all first jumps on the first change curve, and record the dead zone range S of the signal dead zone on the valve position setting value coordinate axis. d and the jump range S of each first jump on the valve position setting value coordinate axis en ; Mark all second jumps on the second change curve, and record the maximum value P of each second jump on the gas pressure coordinate axis en ; The first jump on the first change curve and the second jump on the second change curve correspond one to one based on the valve position setting value, and the valve position setting value where each group of corresponding first jump and second jump are located at the same time is the jump valve position; S4. For each jump valve position, calculate the viscosity coefficient c of each jump valve position n =(S d -S en ) / (S d +S en ), and classify the sticking degree of each jump valve position based on the viscosity coefficient; S5. For each jump valve position, calculate the target pressure value P that the gas drive unit (1) recommends outputting at the jump valve position during the next control. 输出 =P en / c n .

10. The fault diagnosis method according to claim 9, characterized in that: When the sticking degree of each jump valve position is graded based on the viscosity coefficient, the viscosity coefficient in the range of 0 to 1 is divided into multiple levels according to a preset number of grades, wherein the smaller the viscosity coefficient, the higher the sticking degree, and the larger the viscosity coefficient, the lower the sticking degree.

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