Method for detecting a piezoelectric valve of a valve positioner

Abstract

The present application relates to the technical field of valve positioner detection, and specifically discloses a detection method for a piezoelectric valve of a valve positioner, which comprises the following steps: step S1: connecting the positioner to an external valve for maintenance testing, ventilating the air inlet of the positioner, and judging whether the small hole of the top layer of the piezoelectric module is venting outward; if yes, the isolation diaphragm between the pilot layer and the amplification layer is damaged; if not, the following step is continued; step S2: discharging the air inlet piezoelectric valve and the exhaust piezoelectric valve with a resistor, so that the residual voltage is released; the present application can detect the piezoelectric valve of the valve positioner, and can realize deep repair and repeated use of typical faults of the valve positioner, thereby greatly reducing the operation and maintenance cost of enterprises in the aspect of instruments and saving expenses.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valve positioner detection, in particular to a detection method of a piezoelectric valve of a valve positioner. BACKGROUND

[0002] The valve positioner is the most commonly used valve accessory in the chemical industry, which bears the function of converting the AO signal sent by the control system to drive various regulating valves in the production site. At present, from the principle of action, it is mainly divided into two types of valve positioners, namely nozzle-baffle type and piezoelectric valve type. The piezoelectric valve type valve positioner replaces the traditional "nozzle-baffle and pneumatic amplifier" mechanism with a piezoelectric valve, and integrates I / P conversion and power amplification in a piezoelectric module. It has the advantages of saving electricity and gas, but in the field use, it is also found that the failure rate of this type of valve positioner is also relatively high, and the fault points are mainly concentrated on the piezoelectric module. SUMMARY

[0003] The purpose of the present application is to provide a detection method of a piezoelectric valve of a valve positioner, which can detect the piezoelectric valve of the valve positioner.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following scheme:

[0005] Step S1: connecting the positioner to the external valve for maintenance test, ventilating the air inlet of the positioner, judging whether the small hole of the top layer of the piezoelectric module is venting outward, if yes, the isolation diaphragm of the pilot layer and the amplification layer is damaged; if not, the following steps are continued;

[0006] Step S2: discharging the inlet piezoelectric valve and the exhaust piezoelectric valve with a resistor, so that the residual voltage is released;

[0007] Step S3: supplying 24VDC voltage to the inlet piezoelectric valve, listening whether there is a "pop" switching sound, and judging whether the positioner vent is venting outward; if both are, it means that the inlet piezoelectric valve excitation switching is normal, and the step S6 is continued; otherwise, it is faulty;

[0008] Step S4: supplying 24VDC voltage to the exhaust piezoelectric valve, listening whether there is a "pop" switching sound, and judging whether the positioner vent stops venting outward and whether the external valve starts to move; if both are, it means that the exhaust piezoelectric valve excitation switching is normal, and the step S5 is continued; otherwise, it is faulty;

[0009] Step S5: disconnecting the voltage of the exhaust piezoelectric valve, and discharging the exhaust piezoelectric valve with a resistor, listening whether there is a "pop" switching sound, and judging whether the positioner vent starts to vent; if both are, it means that the exhaust piezoelectric valve re-excitation switching is normal; otherwise, it is faulty;

[0010] Step S6: disconnect the voltage of the intake piezoelectric valve, and discharge the intake piezoelectric valve with a resistor, listen to whether there is a "pop" switching sound, and see whether the exhaust of the positioner stops; if both are satisfied, it indicates that the intake piezoelectric valve is normally switched; otherwise, it is a fault;

[0011] Step S7: in the case that both steps 3 and 6 are satisfied, it can be judged that the intake piezoelectric valve is normal.

[0012] Step S8: in the case that both steps 4 and 5 are satisfied, it can be judged that the exhaust piezoelectric valve is normal.

[0013] Further, the specification of the resistor is 1KΩ, 2W.

[0014] Further, the 24VDC power supply is a 10000mAh lithium battery.

[0015] Further, the ventilation device is a micro pneumatic pump, the pressure is 400Kpa, and the flow is 15L / Min.

[0016] Further, the maintenance method for the pilot layer and the amplification layer: carefully disassemble the piezoelectric module, separate the pilot layer and the amplification layer, gently tear off the isolation diaphragm, replace the new one with the original trace, then combine the pilot layer and the amplification layer, and lock the screw.

[0017] Further, the maintenance method for the intake piezoelectric valve: carefully disassemble the piezoelectric module, separate the pilot layer and the amplification layer, unfold the two layers and place them flat, use a small flathead screwdriver to gently lift in the direction of the red arrow, then replace the new intake piezoelectric valve, gently press it, finally combine the pilot layer and the amplification layer, and lock the screw.

[0018] Further, the maintenance method for the exhaust piezoelectric valve: carefully disassemble the piezoelectric module, separate the pilot layer and the amplification layer, unfold the two layers and place them flat, use a small flathead screwdriver to gently lift in the direction of the blue arrow, then replace the new exhaust piezoelectric valve, gently press it, finally combine the pilot layer and the amplification layer, and lock the screw.

[0019] The beneficial effects of the present application are as follows:

[0020] The present application provides a detection method for a valve positioner piezoelectric valve, which can detect the valve positioner piezoelectric valve, and realize deep repair and reuse of typical faults of the valve positioner, greatly reducing the operation and maintenance cost of enterprises in the instrument aspect and saving expenses. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a flowchart of the present application. DETAILED DESCRIPTION

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] Please see Figure 1 This invention provides a method for detecting a valve positioner piezoelectric valve, the method comprising the following steps:

[0024] Step S1: Connect the positioner to the external valve used for maintenance and testing, and vent air into the air inlet of the positioner to determine whether the small hole on the top layer of the piezoelectric module is venting air. If so, the isolation diaphragm between the pilot layer and the amplification layer is damaged; if not, continue with the following steps.

[0025] Step S2: Discharge the intake and exhaust piezoelectric valves with a resistor to release their residual voltage;

[0026] Step S3: Apply 24VDC voltage to the intake pressure valve, listen for a "click" switching sound, and check if there is exhaust gas coming out of the positioner vent. If both are present, the intake pressure valve is switching normally, and continue to step S6; otherwise, there is a fault.

[0027] Step S4: Apply 24VDC voltage to the exhaust piezoelectric valve, listen for a "click" switching sound, and determine whether the positioner vent has stopped venting and whether the external valve has started to move; if both are present, the exhaust piezoelectric valve is switching normally, and continue to step S5; otherwise, there is a fault.

[0028] Step S5: Disconnect the voltage to the exhaust pneumatic valve and discharge the exhaust pneumatic valve with a resistor. Listen for a "click" switching sound and check if the positioner vent has started venting again. If both are present, the exhaust pneumatic valve's re-excitation switching is normal; otherwise, there is a fault.

[0029] Step S6: Disconnect the voltage to the intake pressure valve, then discharge the intake pressure valve with a resistor. Listen for a "click" switching sound and check if the vent of the positioner stops venting. If both conditions are met, the intake pressure valve's re-excitation switching is normal; otherwise, there is a fault.

[0030] Step S7: If both steps 3 and 6 are satisfied, it can be determined that the intake pressure valve is normal;

[0031] Step S8: If both steps 4 and 5 are satisfied, it can be determined that the exhaust pneumatic valve is normal.

[0032] The resistor is specified as 1KΩ, 2W.

[0033] The power supply is a 10000mAh lithium battery with a voltage of 24VDC.

[0034] The ventilation equipment is a miniature pneumatic pump with a pressure of 400 kPa and a flow rate of 15 L / min.

[0035] Isolation diaphragm failure

[0036] The isolation diaphragm is a diaphragm for the pilot stage and the amplification stage of the piezoelectric module, and functions to isolate the two stages. Meanwhile, a local area of the isolation diaphragm can function as a diaphragm for driving the inlet valve and the outlet valve. Therefore, the failure of the isolation diaphragm is generally a gas leakage, and a small hole, etc. If such a problem occurs, the gas source will be uncontrolled into the pilot stage, and a small hole located at the top of the piezoelectric module near the pressure regulating screw will be obviously shown to continuously discharge the external source. Accordingly, it can be determined that the isolation diaphragm has a problem.

[0037] Repair method for the pilot stage and the amplification stage: Carefully disassemble the piezoelectric module, separate the pilot stage and the amplification stage, gently tear off the isolation diaphragm, replace a new one, and then attach the pilot stage and the amplification stage, and lock the screws.

[0038] Inlet piezoelectric valve failure

[0039] Apply 24V voltage to the inlet piezoelectric valve. At this time, the inlet piezoelectric valve should be reversed, and the inlet valve should be simultaneously reversed and driven, so that the gas source is introduced into the output end through the inlet valve. However, since the outlet piezoelectric valve is not powered at this time, the output end and the vent are connected. Therefore, at this time, a continuous gas flow should be obtained at the vent. If no gas flow is observed at the vent at this time, the outlet piezoelectric valve can be applied with a reverse 24V voltage for 1 second to ensure that it is reliably opened. In this case, if no gas flow is observed at the vent, the outlet piezoelectric valve is powered. At this time, in theory, the gas source should be introduced into the output port to drive the valve. However, if the valve does not move at this time, it can be determined that the inlet piezoelectric valve has a problem. Since the inlet piezoelectric valve does not reverse, regardless of the state of the outlet valve, no gas flow is obtained at the output port and the vent.

[0040] Repair method for the inlet piezoelectric valve: Carefully disassemble the piezoelectric module, separate the pilot stage and the amplification stage, spread the two stages and place them flat, and gently lift the inlet piezoelectric valve in the direction of the red arrow with a small flathead screwdriver. Then, replace the new inlet piezoelectric valve, gently press it, and finally attach the pilot stage and the amplification stage, and lock the screws.

[0041] Outlet piezoelectric valve failure

[0042] Apply 24V voltage to the inlet piezoelectric valve. At this time, the inlet piezoelectric valve should be reversed, and the inlet valve should be simultaneously reversed and driven, so that the gas source is introduced into the output end through the inlet valve. However, since the outlet piezoelectric valve is not powered at this time, the output end and the vent are connected. Therefore, at this time, a continuous gas flow should be obtained at the vent. If no gas flow is observed at the vent at this time, the outlet piezoelectric valve can be applied with a reverse 24V voltage for 1 second to ensure that it is reliably opened. In this case, if no gas flow is observed at the vent, the outlet piezoelectric valve is powered. At this time, in theory, the gas source should be introduced into the output port to drive the valve. However, if the valve does not move at this time, it can be determined that the inlet piezoelectric valve has a problem. Since the inlet piezoelectric valve does not reverse, regardless of the state of the outlet valve, no gas flow is obtained at the output port and the vent.

[0043] The maintenance method of the exhaust piezoelectric valve: carefully disassemble the piezoelectric module, separate the pilot layer and the amplification layer, unfold the two layers and lay flat, gently lift up along the blue arrow direction with a small flathead screwdriver, the exhaust piezoelectric valve can be pulled out, then replace the new exhaust piezoelectric valve and gently press, finally close the pilot layer and the amplification layer, lock the screw, and the valve positioning device is completed.

[0044] The valve positioning device and the external valve for maintenance test in the application are all prior art, and the person skilled in the art can clearly understand, and no detailed description is made here.

[0045] The above only describes the preferred embodiments of the application, and should not be understood as limiting the application. Any equivalent changes and modifications made within the scope of the application should be included in the scope of the application.

Claims

1. A method of detecting a piezoelectric valve of a valve positioner, characterized by: The method comprises the following steps: Step S1: connecting the positioner to the external valve for maintenance test, ventilating the air inlet of the positioner, judging whether the small hole of the top layer of the piezoelectric module exhausts outward, and if yes, the isolation diaphragm of the pilot layer and the amplification layer is damaged; if not, the following steps are continued; Step S2: discharging the inlet piezoelectric valve and the exhaust piezoelectric valve by using a resistor, so that the residual voltage is released; Step S3: supplying 24VDC voltage to the inlet piezoelectric valve, listening to whether there is a "pop" switching sound, and judging whether the positioner exhaust port exhausts outward; if both are yes, it indicates that the inlet piezoelectric valve excitation switching is normal, and step S6 is continued; otherwise, it is faulty; Step S4: supplying 24VDC voltage to the exhaust piezoelectric valve, listening to whether there is a "pop" switching sound, and judging whether the positioner exhaust port stops exhausting outward and whether the external valve starts to move; if both are yes, it indicates that the exhaust piezoelectric valve excitation switching is normal, and step S5 is continued; otherwise, it is faulty; Step S5: disconnecting the voltage of the exhaust piezoelectric valve, and discharging the exhaust piezoelectric valve by using a resistor, listening to whether there is a "pop" switching sound, and judging whether the positioner exhaust port starts to exhaust; if both are yes, it indicates that the exhaust piezoelectric valve re-excitation switching is normal; otherwise, it is faulty; Step S6: disconnecting the voltage of the inlet piezoelectric valve, and discharging the inlet piezoelectric valve by using a resistor, listening to whether there is a "pop" switching sound, and judging whether the positioner exhaust port stops exhausting; if both are yes, it indicates that the inlet piezoelectric valve re-excitation switching is normal; otherwise, it is faulty; Step S7: under the condition that steps 3 and 6 are both satisfied, it can be judged that the inlet piezoelectric valve is normal; Step S8: under the condition that steps 4 and 5 are both satisfied, it can be judged that the exhaust piezoelectric valve is normal; The maintenance method for the pilot layer and the amplification layer: carefully disassembling the piezoelectric module, separating the pilot layer and the amplification layer, gently tearing off the isolation diaphragm, replacing a new one which is attached to the original trace, then combining the pilot layer and the amplification layer, and locking the screw; The maintenance method for the inlet piezoelectric valve: carefully disassembling the piezoelectric module, separating the pilot layer and the amplification layer, unfolding the two layers and laying them flat, gently lifting the inlet piezoelectric valve in the direction of the red arrow by using a small flathead screwdriver, then replacing a new inlet piezoelectric valve and gently pressing it, finally combining the pilot layer and the amplification layer, and locking the screw; The maintenance method for the exhaust piezoelectric valve: carefully disassembling the piezoelectric module, separating the pilot layer and the amplification layer, unfolding the two layers and laying them flat, gently lifting the exhaust piezoelectric valve in the direction of the blue arrow by using a small flathead screwdriver, then replacing a new exhaust piezoelectric valve and gently pressing it, finally combining the pilot layer and the amplification layer, and locking the screw.

2. The method of claim 1, wherein: The specification of the resistor is 1KΩ, 2W.

3. The method of claim 1, wherein: The power supply of 24VDC voltage is a 10000mAh lithium battery.

4. The method of claim 1, wherein: The ventilation equipment is a miniature pneumatic pump, the pressure is 400Kpa, and the flow is 15L / Min.

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