A Monitoring System for the Operating Status and Remote Early Warning of a Pneumatic Diaphragm Actuator

Abstract

The present invention discloses a system for monitoring the operating state of a pneumatic diaphragm actuator and remote early warning, which uses an early warning system combining a pressure switch, a solid-state relay, an electric bell, and a central signal flashing alarm. Through acoustic and optical alarms, it provides unprecedented situational awareness capabilities for the process control system, and can completely replace the traditional auxiliary system configuration method of domestic pneumatic diaphragm actuators. It solves the problems of difficult operation state monitoring and fault diagnosis of pneumatic diaphragm actuators, and has broad popularization and application value and product extension value. After adopting the system of the present invention, a remote early warning response is triggered when the pneumatic diaphragm actuator enters the self-locking position, providing timely and accurate fault diagnosis alarm information for the operator. The control room can take corresponding measures in a timely manner according to this alarm signal to achieve the safe production of the controlled equipment. The system of the present invention has a compact structure and sensitive actions, and users can easily install it and connect the electrical and pneumatic circuits.

Description

Technical Field

[0001] The present invention relates to the technical field of instrument automatic control, and particularly to a pneumatic diaphragm actuator operation status monitoring and remote warning system. Background Art

[0002] A pneumatic diaphragm actuator is a device that uses compressed air or nitrogen as a power source, receives a standard current signal of 4 - 20 mA.DC given by a regulator (computer), and converts this signal into a thrust (linear stroke displacement) to control the opening degree of a pneumatic diaphragm control valve, thereby achieving the regulation and control of the parameters of the medium in the conveying pipeline. The main body of the commonly used pneumatic diaphragm actuator in China currently consists of a diaphragm cover, a corrugated diaphragm, a push rod component, a spring, a bracket, and a valve body. The accessories used include an electric valve positioner, an air filter pressure reducing valve, and a pneumatic self-locking valve. During actual use, when there are faults in the diaphragm air chamber or the electric valve positioner of the pneumatic diaphragm actuator, or when the three-break (broken air source, broken power supply, broken signal) protection action of the pneumatic diaphragm actuator occurs, the following main problems exist with the existing pneumatic diaphragm actuator:

[0003] 1. When the pneumatic diaphragm actuator performs the three-break protection action (i.e., loses the control signal, instrument air source, or power supply), it has a self-locking function, but there is no protection status output contact for alarm and no remote warning function, so the duty personnel cannot take corresponding measures in a timely manner.

[0004] 2. The diaphragm air chamber is the power component of the actuator. After long-term use, due to wear, leakage, and air leakage of its corrugated diaphragm, the output force of the actuator will be insufficient and the action will be slow. When the pneumatic diaphragm actuator is running, the problem of wear, leakage, and air leakage of the corrugated diaphragm cannot be diagnosed, resulting in the pneumatic diaphragm control valve being unable to achieve correct positioning.

[0005] 3. During the production process, due to process requirements, when the pneumatic self-locking valve fails in an accident state (including broken air, broken power, broken signal) and cannot keep the pneumatic diaphragm actuator in position, it is required that the pneumatic diaphragm control valve be fully opened (fully closed), but the existing pneumatic diaphragm actuator does not have a remote warning function for the fully opened (fully closed) state of the pneumatic diaphragm control valve. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problem that the existing pneumatic diaphragm actuator does not have a remote warning function during the three-break (broken air source, broken power supply, broken signal) protection action and faults, which is harmful to the safe operation of the controlled production equipment, and to provide a pneumatic diaphragm actuator operation status monitoring and remote warning system to improve the operation quality of the controlled equipment.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A pneumatic diaphragm actuator operating status monitoring and remote warning system, including an air filter pressure reducing valve. The inlet of the air filter pressure reducing valve is connected to the air source, and the outlet of the air filter pressure reducing valve is connected to the inlet of the air safety valve. The output pipeline of the air safety valve is respectively connected to the air sources of a pressure switch, a smart valve positioner, and a two-position three-way solenoid valve. The air source outlet of the two-position three-way solenoid valve is connected to the air source inlet of a pneumatic self-locking valve. The output interface OUT1 of the pneumatic self-locking valve is connected to the diaphragm air chamber of the pneumatic diaphragm actuator, and the pneumatic diaphragm actuator is connected to a regulating valve. The output pneumatic signal of the smart valve positioner is connected to the input interface IN1 of the pneumatic self-locking valve through P1.

[0009] The pneumatic diaphragm actuator operating status monitoring and remote warning system further includes a solid state relay. The pressure switch, the two-position three-way solenoid valve, and the solid state relay are all powered by an electronic switch. The low limit alarm output terminal of the pressure switch is electrically connected to a flash alarm, and the alarm output terminal of the solid state relay is electrically connected to the flash alarm.

[0010] The alarm output terminal, limit 1 alarm output terminal, and limit 2 alarm output terminal of the smart valve positioner are respectively electrically connected to the flash alarm.

[0011] The signal input terminal of the electronic switch is electrically connected to the signal output terminal of the signal source, and the signal output terminal of the electronic switch is electrically connected to the signal input terminal of the smart valve positioner.

[0012] As a further improvement of the technical solution of the present invention, a stop valve is provided between the air source outlet and the air filter pressure reducing valve.

[0013] Further, the smart valve positioner is a SIPART PS2 series Siemens smart valve positioner.

[0014] Further, the valve position feedback device of the smart valve positioner is connected to the displacement feedback rod of the pneumatic diaphragm actuator.

[0015] Further, the pneumatic self-locking valve is a single-channel pneumatic self-locking valve.

[0016] Further, the flash alarm is respectively electrically connected to an electric bell, a test button, and a confirmation button.

[0017] The beneficial effects of adopting the present invention are as follows:

[0018] 1. After adopting the system of the present invention, when the pneumatic diaphragm actuator enters the self-locking position state, a remote warning response is triggered, providing timely and accurate fault diagnosis alarm information for the operator. The operator in the control room can take corresponding measures in time according to this alarm signal to achieve the safe production of the controlled equipment.

[0019] 2. The system structure of the present invention is compact and the action is sensitive. Users can easily install it and connect the electrical and pneumatic circuits. After being used in conjunction with the Siemens intelligent valve positioner of the SIPART PS2 series with an alarm template, when the air source, power supply or input signal source is suddenly interrupted during the operation of the actuator, the pneumatic diaphragm actuator maintains the working position before the interruption to ensure that the process parameters in the regulation loop remain unchanged, the regulated action of the medium is not interrupted, and it does not pose a hazard to the safe operation of the controlled production equipment, thereby improving the operation quality of the controlled equipment.

[0020] 3. By using a warning system combining a pressure switch + solid-state relay + electric bell + central signal flashing alarm, the present invention provides unprecedented situation awareness capabilities for the process control system through audible and visual alarms, and can completely replace the traditional auxiliary system configuration method of domestic pneumatic diaphragm actuators, solving the problems of difficult operation situation monitoring and fault diagnosis of pneumatic diaphragm actuators, and having wide popularization and application value and product extension value. Brief Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the operation state monitoring and remote warning system of the pneumatic diaphragm actuator of the present invention;

[0022] Figure 2 It is a schematic diagram of the alarm template of the Siemens intelligent valve positioner;

[0023] Reference Numerals: 1 - air source, 2 - globe valve, 3 - air filter pressure reducing valve, 4 - air safety valve, 5 - pressure switch, 6 - Siemens intelligent valve positioner, 7 - two-position three-way solenoid valve, 8 - pneumatic self-locking valve, 9 - electronic switch, 10 - solid-state relay, 11 - signal source, 12 - flashing alarm, 13 - electric bell, 14 - test button, 15 - confirmation button, 16 - pneumatic diaphragm actuator, 17 - regulating valve, 18 - displacement feedback rod, 19 - Siemens intelligent valve positioner alarm template. Detailed Embodiment

[0024] The connection relationship and working process of the present invention will be described in detail below with reference to the drawings.

[0025] As Figure 1As shown in the figure, a pneumatic diaphragm actuator operating state monitoring and remote warning system provided by the present invention includes an air filter pressure reducing valve 3. The inlet of the air filter pressure reducing valve 3 is connected to the air source 1, and a stop valve 2 is provided between the outlet of the air source 1 and the air filter pressure reducing valve 3. The outlet of the air filter pressure reducing valve 3 is connected to the inlet of the air safety valve 4. The output pipeline of the air safety valve 4 is respectively connected to the air sources of the pressure switch 5, the Siemens intelligent valve positioner 6, and the two-position three-way solenoid valve 7. The air source outlet of the two-position three-way solenoid valve 7 is connected to the air source inlet of the pneumatic self-locking valve 8. The output interface OUT1 of the pneumatic self-locking valve 8 is connected to the diaphragm air chamber of the pneumatic diaphragm actuator 16, and the pneumatic diaphragm actuator 16 is connected to the regulating valve 17. The output pneumatic signal of the intelligent valve positioner 6 is connected to the input interface IN1 of the pneumatic self-locking valve 8 through P1.

[0026] Among them, the pneumatic diaphragm actuator operating state monitoring and remote warning system further includes a solid state relay 10. The pressure switch 5, the two-position three-way solenoid valve 7, and the solid state relay 10 are all powered by the electronic switch 9. The low limit alarm output terminal of the pressure switch 5 is electrically connected to the flash alarm 12, and the alarm output terminal of the solid state relay 10 is electrically connected to the flash alarm 12.

[0027] The alarm output terminal, limit 1 alarm output terminal, and limit 2 alarm output terminal of the Siemens intelligent valve positioner 6 are respectively electrically connected to the flash alarm 12. The signal input terminal of the electronic switch 9 is electrically connected to the signal (4 - 20 mA) output terminal of the signal source 11, and the signal output terminal of the electronic switch 9 is electrically connected to the signal input terminal of the Siemens intelligent valve positioner 6. The flash alarm 12 is respectively electrically connected to the electric bell 13, the test button 14, and the confirmation button 15.

[0028] The above-mentioned Siemens intelligent valve positioner 6 is a SIPART PS2 series Siemens intelligent valve positioner, and the valve position feedback device of the Siemens intelligent valve positioner 6 is connected to the displacement feedback rod 18 of the pneumatic diaphragm actuator. The pneumatic self-locking valve 8 is a single-channel pneumatic self-locking valve.

[0029] The maximum working pressure of the air filter pressure reducing valve 3 is 1.0 MPa, the filtration accuracy is 5 μm, and the pressure regulation range is 0.05 - 0.8 MPa. The air filter pressure reducing valve 3 filters particles > 5 μm in the nitrogen or compressed air source and reduces the pressure to 0.16 - 0.25 MPa. The maximum pressure that the stop valve 2 can withstand is 1.6 MPa, which is used to cut off the air source 1 during maintenance or replacement of the air filter pressure reducing valve 3.

[0030] The air safety valve 4 is used in conjunction with the air filter pressure reducing valve 3. When the instrument pressure of the air source 1 is too high and the output pressure of the air filter pressure reducing valve 3 exceeds the set value, the air safety valve 4 will release the pressure higher than the set value until the instrument pressure returns to normal, protecting the function of the diaphragm air chamber of the Siemens intelligent valve positioner and the pneumatic diaphragm actuator 16, and preventing the air source pressure from exceeding the upper limit of the rubber diaphragm pressure, so as to avoid the diaphragm from rupturing under high air pressure.

[0031] The pressure switch 5 has functions of pressure display and low limit alarm output. The pressure range is 0 - 1.6 MPa, and the power supply voltage is 24 VDC. The measuring air circuit of the pressure switch 5 is connected to the outlet pipeline of the air safety valve 4. When the pressure of the air source 1 ≤ 0.14 MPa, the pressure switch gives an alarm output and turns on the flashing alarm 12 for alarm.

[0032] The signal source 11 sends a 4 - 20 mA.DC current control signal into the electronic switch 9, and the electronic switch 9 then sends this signal into the Siemens intelligent valve positioner 6. When the current signal of the signal source 11 ≤ 3.2 mA, the relay contact of the electronic switch 9 disconnects, and the two - position three - way solenoid valve 7 and the solid - state relay 10 lose power simultaneously, turning on the flashing alarm 12 for alarm.

[0033] When the diaphragm air chamber of the pneumatic diaphragm actuator 16 leaks, the output force is insufficient and it cannot reach the set position, or when the intelligent valve positioner 6 fails, the alarm channels 31 and 32 of the alarm template 19 of the Siemens intelligent valve positioner close, outputting an alarm signal and turning on the flashing alarm 12 for alarm.

[0034] When the pneumatic diaphragm actuator 16 receives the pneumatic signal output by the Siemens intelligent valve positioner 6, causing the valve stem to actuate and drive the valve core to reach the fully open (fully closed) position of the pneumatic diaphragm regulating valve, the limits 1 (terminals 41 and 42) and limits 2 (terminals 51 and 52) of the alarm template of the Siemens intelligent valve positioner 6 close, outputting an alarm signal and turning on the flashing alarm 12 for alarm.

[0035] In addition, the input terminals of the flashing alarm 12 are respectively connected to the pressure switch 5, the solid - state relay 10, the alarm channel, the limit 1 channel, and the limit 2 channel of the alarm template of the Siemens intelligent valve positioner 6. When the flashing alarm 12 is turned on, the electric bell 13 is simultaneously turned on. Among them, the flashing alarm 12 emits light and the electric bell 13 emits sound to achieve audible and visual alarm.

[0036] A method for monitoring the operating state and remote early warning of a pneumatic diaphragm actuator provided by the present invention has the following working process:

[0037] Connect N with a pressure of 0.8 - 1.0 MPa from the outside 2Or the compressed air gas source 1 enters the air filter pressure reducing valve 3 via the stop valve 2. The air filter pressure reducing valve 3 filters and reduces the gas source pressure to 0.16 - 0.25 MPa, and then, via the air safety valve 4, it is sent to the working gas source inlets of the pressure switch 5, the two-position three-way solenoid valve 7, and the Siemens intelligent valve positioner respectively. When the instrument pressure of the gas source 1 is too high or the instrument output pressure exceeds the set value due to a malfunction of the air filter pressure reducing valve 3, the air safety valve 4 will release the excessive air pressure, stabilize the pressure, and play a role in protecting the diaphragm air chamber of the Siemens intelligent valve positioner and the pneumatic diaphragm actuator. The output pneumatic signal of the Siemens intelligent valve positioner enters the diaphragm air chamber of the pneumatic diaphragm actuator 16 via P1. The thrust generated by the pneumatic pressure on the diaphragm makes the valve stem move, and the distance of movement is the stroke of the pneumatic diaphragm actuator 16.

[0038] Air pressure cut-off protection and alarm: It is mainly achieved by the pneumatic self-locking valve 8. When the air pressure is higher than the set value of the pneumatic self-locking valve 8, the pneumatic self-locking valve 8 opens, and the output pneumatic signal of the positioner is communicated with the diaphragm air chamber of the pneumatic diaphragm actuator 16, which is the normal automatic working state. When the air pressure is lower than the set value of the pneumatic self-locking valve 8, the pneumatic self-locking valve 8 closes to maintain the original position of the load, realizing the air pressure cut-off self-locking protection. When the gas source pressure after being reduced by the air filter pressure reducing valve 3 ≤ 0.12 MPa, the pressure switch 5 sends out an alarm signal to connect the flashing alarm 12 for alarm.

[0039] Power cut-off protection and alarm: It is mainly achieved by the two-position three-way solenoid valve 7. When the power supply is normal, the two-position three-way solenoid valve 7 connects the control air circuit of the pneumatic self-locking valve 8 to make the pneumatic self-locking valve 8 open, which is the normal automatic working state. When the power supply disappears, the two-position three-way solenoid valve 7 switches to evacuate the control air source of the single-channel pneumatic self-locking valve 8, and the single-channel pneumatic self-locking valve 8 closes to maintain the original position of the load, realizing the power cut-off protection. At the same time, the solid-state relay 10 loses power and connects the flashing alarm 12 for alarm.

[0040] Signal cut-off protection and alarm: When the signal source 11 is connected to the 4 - 20 mA.DC circuit of the electronic switch 9 and the Siemens intelligent valve positioner 6 and there is a break in the circuit or the input signal source 11 current signal < 3.2 mA.DC, the contacts of the electronic switch 9 disconnect. The two-position three-way solenoid valve 7 and the solid-state relay 10 lose power at the same time. The alarm terminal of the solid-state relay 10 closes and outputs to connect the flashing alarm 12 for alarm. At the same time, the air circuit of the two-position three-way solenoid valve 7 is cut off due to power loss, and the single-channel pneumatic self-locking valve 8 closes to realize self-locking and position holding.

[0041] Fault alarm of pneumatic diaphragm actuator or intelligent valve positioner: When there is air leakage in the diaphragm air chamber of the pneumatic diaphragm actuator 16, resulting in insufficient output force, slow movement, and inability to reach the set position, or when the intelligent valve positioner fails, the output terminals 31 and 32 of the Siemens intelligent valve positioner alarm template 19 are closed, outputting an alarm signal to turn on the flash alarm 12 for alarm.

[0042] Full-open and full-close alarm of pneumatic diaphragm control valve: During the production process, due to process requirements, when the pneumatic self-locking valve 8 fails in an accident state (including air cut-off, power cut-off, signal cut-off), it is required that the pneumatic diaphragm control valve be fully open (fully closed). The output terminals 41 and 42 of the Siemens intelligent valve positioner alarm template 19, that is, the limit maximum value, (the output terminals 51 and 52 are the limit minimum value) are closed to output an alarm signal, respectively turning on the flash alarm 12 for alarm.

[0043] The test button 14 and the confirmation button 15 are used to confirm whether the flash alarm 12 is working properly. When the flash alarm 12 is turned on, the electric bell 13 is also turned on. Among them, the flash alarm 12 emits light, and the electric bell 13 emits sound to achieve audible and visual alarm. When the test button 14 is closed, the flash alarm 12 is turned on, and when the confirmation button 15 is closed, the flash alarm 12 is cut off.

[0044] The above are only the preferred embodiments of the present invention and do not limit the present invention. It should be pointed out that for those of ordinary skill in the art, under the technical inspiration provided by the present invention, other equivalent variations and improvements can be made, all of which can achieve the purpose of the present invention and should be regarded as the protection scope of the present invention.

Claims

1. A pneumatic diaphragm actuator operating status monitoring and remote warning system, characterized in that, it includes an air filter pressure reducing valve, the inlet of the air filter pressure reducing valve is communicated with the air source, the outlet of the air filter pressure reducing valve is connected with the inlet of the air safety valve, the output pipeline of the air safety valve is respectively connected with the air sources of a pressure switch, a smart valve positioner, and a two-position three-way solenoid valve, the air source outlet of the two-position three-way solenoid valve is connected with the air source inlet of a pneumatic self-locking valve, the output interface OUT1 of the pneumatic self-locking valve is connected with the diaphragm air chamber of the pneumatic diaphragm actuator, and the pneumatic diaphragm actuator is connected with a regulating valve; the output pneumatic signal of the smart valve positioner is connected with the input interface IN1 of the pneumatic self-locking valve through P1; the pneumatic diaphragm actuator operating status monitoring and remote warning system further includes a solid state relay, and the pressure switch, the two-position three-way solenoid valve, and the solid state relay are all powered by an electronic switch; the low limit alarm output terminal of the pressure switch is electrically connected with a flash alarm, and the alarm output terminal of the solid state relay is electrically connected with the flash alarm; the alarm output terminal, the limit 1 alarm output terminal, and the limit 2 alarm output terminal of the smart valve positioner are respectively electrically connected with the flash alarm; the signal input terminal of the electronic switch is electrically connected with the signal output terminal of the signal source, and the signal output terminal of the electronic switch is electrically connected with the signal input terminal of the smart valve positioner; a stop valve is provided between the air source outlet and the air filter pressure reducing valve; the pneumatic self-locking valve is a single-channel pneumatic self-locking valve.

2. The pneumatic diaphragm actuator operating status monitoring and remote warning system according to claim 1, characterized in that, the smart valve positioner is a SIPART PS2 series Siemens smart valve positioner.

3. The pneumatic diaphragm actuator operating status monitoring and remote warning system according to claim 2, characterized in that, the valve position feedback device of the smart valve positioner is connected with the displacement feedback rod of the pneumatic diaphragm actuator.

4. The pneumatic diaphragm actuator operating status monitoring and remote warning system according to any one of claims 1-3, characterized in that, the flash alarm is respectively electrically connected with an electric bell, a test button, and a confirmation button.

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