A method and device for detecting and diagnosing faults of an online pH meter

Abstract

The present invention discloses a method and device for detecting and diagnosing faults of an online pH meter, comprising establishing an operating threshold value of the online pH meter, obtaining the measured value of the online pH meter, and determining whether the measured value of the online pH meter deviates from the operating threshold value. If the measured value of the online pH meter exceeds the operating threshold value, the online pH meter is self-checked. An indication error control range of the online pH meter is established, and based on the obtained self-check result of the online pH meter, it is determined whether the indication error of the online pH meter exceeds the control range. If the indication error meets the control range, the online pH meter is diagnosed as having no faults; if the indication error exceeds the control range, the online pH meter is fault diagnosed and the fault type is output. The present invention realizes automatic inspection and fault judgment of the online pH meter when the monitoring data is abnormal, and can automatically complete the fault detection and fault diagnosis of the online pH meter, which is more intelligent and efficient than manual detection and judgment.

Description

Technical Field

[0001] The invention belongs to the technical field of online pH meter detection, and relates to a method and a device for detecting and diagnosing faults of an online pH meter. Background Art

[0002] Thermal power plants use online pH meters to continuously monitor the acidity and alkalinity of their water vapor circulation systems. This allows them to control the pH value of the water vapor system within thermal power generators and prevent corrosion in thermal equipment and pipelines. Because the water in power plant water vapor circulation systems is highly pure, online pH meters are electrochemical instruments, making their accuracy susceptible to interference from both online and pure water factors, which can lead to errors.

[0003] The measurement data from online chemical instruments in thermal power plants is typically uploaded to the DCS control system. If the online pH meter reading at a certain measurement point exceeds the operating threshold, the DCS system will issue an alarm. However, the alarm signal cannot determine whether the fault at that measurement point is caused by water quality issues or a problem with the pH meter itself. Staff can only troubleshoot the source of the fault through on-site testing and manual analysis. This method is neither fast nor intelligent, and requires a significant amount of time for manual troubleshooting, urgently requiring improvement. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a method and device for online pH meter fault detection and diagnosis, which can automatically complete the fault detection and fault diagnosis work of the online pH meter, and is more intelligent and efficient than manual detection and judgment.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for detecting and diagnosing faults of an online pH meter, comprising:

[0007] Obtaining a measurement value of an online pH meter and determining whether the measurement value of the online pH meter is normal according to a set measurement threshold;

[0008] If the measured value of the online pH meter exceeds the measurement threshold, the online pH meter is self-checked;

[0009] Obtaining an error value of an online pH meter and determining a state of the online pH meter according to a set error threshold;

[0010] If the error value is within the range of the error threshold, the online pH meter has no fault; if the error value exceeds the range of the error threshold, the online pH meter is diagnosed for fault and the fault type is output.

[0011] Preferably, the self-test method of the online pH meter is as follows:

[0012] Cut off the online measurement water channel of the online pH meter, pass the standard solution into the online pH meter, obtain the standard solution measurement value of the online pH meter, and determine the error value of the online pH meter according to the measurement value of the online pH meter and the measurement value of the standard solution.

[0013] Preferably, the calculation method of the error value δ of the online pH meter is as follows:

[0014] δ=S﹣S b

[0015] Where, δ is the indication error of the online pH meter, S is the measured value of the online pH meter, and S b is the measured value of the standard solution.

[0016] Preferably, the fault types of the online pH meter include: abnormal water sample flow fault, abnormal water sample temperature fault, electrode slope offset fault and electrode zero drift fault.

[0017] Preferably, the fault diagnosis method of the online pH meter comprises the following steps:

[0018] Step 1: Obtain the water sample flow rate of the online pH meter. When the water sample flow rate exceeds the set flow rate threshold range, the online pH meter is at a water sample flow abnormality fault.

[0019] When the water sample flow rate is within the set flow threshold range, execute step 2;

[0020] Step 2: Obtain the water sample temperature of the online pH meter. If the water sample temperature exceeds the set temperature threshold range, the online pH meter is at a water sample temperature abnormality fault.

[0021] When the water sample temperature is within the set temperature threshold range, execute step 3;

[0022] Step 3: Obtain the electrode slope of the online pH meter. If the electrode slope exceeds the set slope threshold range, the online pH meter has an electrode slope offset fault.

[0023] An online pH meter fault detection and diagnosis device includes a controller, a standard solution, and a three-way electric valve;

[0024] The water inlet end of the three-way electric valve is connected to the online water sample, the standard solution end of the three-way electric valve is connected to the standard solution, and the water outlet end of the three-way electric valve is connected to the online pH meter;

[0025] The controller is connected to obtain a measurement value of the online pH meter and determines a fault state of the online pH meter based on the measurement value.

[0026] Preferably, the standard solution end of the three-way electric valve is connected to the standard solution through a peristaltic pump.

[0027] Preferably, the water outlet of the three-way electric valve is connected to the water inlet of the pH electrode, the pH electrode is connected to an online pH meter, and the pH electrode is arranged in the circulation pool.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] The present invention provides a method and device for detecting and diagnosing faults in an online pH meter. The method obtains the measured value of the online pH meter to determine whether the meter's measurement status deviates from an operating threshold. When the measured value exceeds the operating threshold, the online pH meter performs a self-test. Based on the obtained self-test result, the online pH meter's indication error is determined to be outside the control range. If the indication error is within the control range, the online pH meter is diagnosed as fault-free. If the indication error is outside the control range, the online pH meter is diagnosed as fault-free and the diagnostic result is output. Workers can then proceed based on the diagnostic result, avoiding inconsistent detection and diagnostic methods that can confuse maintenance personnel, increase maintenance workload, and even prevent the cause of the fault from being diagnosed. The present invention implements automatic inspection and fault diagnosis of online pH meters when monitoring data is abnormal. It also automatically inspects and calibrates online chemical instruments without manual intervention during the calibration process, avoiding the influence of offline factors during the entire instrument calibration process and ensuring accurate measurement of online chemical instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a method for detecting and diagnosing faults of an online pH meter in Example 1 of the present invention;

[0031] Figure 2 This is a connection diagram of a self-test module of an online pH meter fault detection and diagnosis device in Example 2 of the present invention;

[0032] Figure 3 This is a schematic structural diagram of an online pH meter fault detection and diagnosis device in Example 3 of the present invention;

[0033] Figure 4 This is a structural diagram of an online pH meter fault detection and diagnosis device in a fourth embodiment of the present invention; DETAILED DESCRIPTION

[0034] The present invention will be described in further detail below in conjunction with the accompanying drawings, which are provided to explain the present invention rather than to limit it. It should also be noted that, for ease of description, the accompanying drawings only show parts related to the present invention rather than all structures.

[0035] Example 1

[0036] Figure 1This is a flow chart of a method for detecting and diagnosing faults of an online pH meter in accordance with the first embodiment of the present invention. This embodiment is applicable to detecting and diagnosing faults of an online pH meter. This method can be performed by a device for detecting and diagnosing faults of an online pH meter in accordance with the embodiment of the present invention. The device can be implemented in software and / or hardware. Figure 1 As shown, the method specifically includes the following steps:

[0037] S100, setting an operating threshold of an online pH meter, obtaining a measured value of the online pH meter, and determining whether the measured value of the online pH meter deviates from the operating threshold;

[0038] The online pH meter can be an online pH meter of any measuring point in the control system, for example, it can be an online pH meter of feed water, steam or condensate. The operating threshold corresponding to the online pH meter is set according to the operating conditions and water quality characteristics of the measuring point.

[0039] S200, if the measured value of the online pH meter exceeds the operating threshold, perform a self-check on the online pH meter;

[0040] When the online pH meter starts self-testing, the controller first cuts off the online pH meter's online measurement water channel, then passes the pH standard solution into the online pH meter. By comparing the error between the online pH meter's measured value and the standard solution's value, the error value δ=S﹣S b .

[0041] Among them, δ is the error value of the online pH meter, S is the measured value of the online pH meter, S b is the pH value of the standard solution.

[0042] Preferably, the pH standard solution may be a standard buffer solution with a pH value of 6.86 and 9.18, or a low-conductivity pH standard solution with a conductivity lower than 10 μS / cm.

[0043] S300, setting an error threshold range of the online pH meter, and determining whether an error value of the online pH meter exceeds the error threshold range based on the obtained self-test result of the online pH meter;

[0044] S400: If the error value meets the error threshold range, diagnose that the online pH meter is fault-free; if the error value exceeds the error threshold range, perform fault diagnosis on the online pH meter and output the diagnosis result.

[0045] Online pH meter fault diagnosis types include: abnormal water sample flow fault, abnormal water sample temperature fault, electrode slope offset fault and electrode zero drift fault.

[0046] Example 2

[0047] See Figure 2, an online pH meter fault detection and diagnosis device includes a controller 1, a standard solution 5, a peristaltic pump 6, and a three-way electric valve 7.

[0048] The water inlet end of the three-way electric valve 7 is connected to the online water sample, the standard solution end of the three-way electric valve 7 is connected to the outlet of the peristaltic pump 6, the inlet of the peristaltic pump 6 is connected to the standard solution 5, the water outlet end of the three-way electric valve 7 is connected to the water inlet end of the pH electrode 3, and the outlet of the circulation pool 4 is facing the air.

[0049] The controller can collect signals from the online pH meter 2, the peristaltic pump 6, and the three-way electric valve 7, and control the peristaltic pump 6 and the three-way electric valve 7;

[0050] The pH electrode 3 is installed in the circulation pool 4 and is connected to the online pH meter 2 via a cable.

[0051] The implementation steps are:

[0052] During normal measurement, the standard liquid end of the three-way electric valve 7 is disconnected, the water inlet and outlet ends are connected, and the solution flowing into the circulation pool 4 is the online water sample. At this time, the measurement value of the online pH meter 2 of the pH electrode is the pH value of the online water sample;

[0053] During self-test, the water inlet end of the three-way electric valve 7 is disconnected, and the standard solution end and the water outlet end are connected. The peristaltic pump 6 continuously adds the standard solution 7 into the circulation pool 4. At this time, the measurement value of the online pH meter 2 is the standard solution.

[0054] Example 3

[0055] Figure 3 This is a structural diagram of an online pH meter fault detection and diagnosis system in embodiment 3 of the present invention; the online pH meter fault detection and diagnosis system includes an acquisition module, a judgment module, a self-test module, a diagnosis module, and a processing module. Among them:

[0056] Acquisition module 11, used to obtain the measurement value of the online pH meter;

[0057] The acquisition module 11 may obtain the measured value of the online pH meter directly from the online pH meter, or may obtain the value from a DCS control system, a PLC control system or a SIS monitoring system by using a communication method.

[0058] The judgment module 12 is used to set an operation threshold and judge whether the pH measurement value of the online pH meter deviates from the operation threshold;

[0059] A self-test module 13 is configured to start a self-test function of the online pH meter when the measured value of the online pH meter exceeds an operating threshold, and perform an online test on the online pH meter using a standard solution;

[0060] The diagnostic module 14 is used to set an error threshold range, calculate the error value of the online pH meter, and determine whether the error value of the online pH meter exceeds the error threshold range;

[0061] The processing module 15 is used to determine the fault source of the online pH meter, and output the fault and issue an early warning.

[0062] The processing module 15 diagnoses that the online pH meter is fault-free if the error value of the online pH meter meets the error threshold range; if the error value of the online pH meter exceeds the error threshold range, the processing module 15 performs fault diagnosis on the online pH meter and outputs the fault type.

[0063] Example 4

[0064] Figure 4 Schematic diagram of a flow chart of an online pH meter fault detection and diagnosis method in embodiment 4 of the present invention.

[0065] Troubleshooting involves the following steps:

[0066] Step 1: Determine whether the error value of the online pH meter is within the error threshold range. If so, diagnose that the online pH meter is measuring accurately and output an online pH meter fault-free signal. Otherwise, the error value of the online pH meter is not within the control range and execute step 2.

[0067] Step 2: Check the water sample flow rate of the online pH meter to determine whether the water sample flow rate of the online pH meter is within the normal range. If the water sample flow rate is abnormal, diagnose it as a water sample flow abnormality fault and output the fault diagnosis type. Otherwise, execute step 3.

[0068] Step 3: Check the water sample temperature of the online pH meter to determine whether the water temperature of the online pH meter is within the normal temperature range. If the water sample temperature is not within the normal range, it is diagnosed as an abnormal water sample temperature fault and the fault diagnosis type is output. Otherwise, go to step 4.

[0069] Step 4: Check the electrode slope of the online pH meter to determine whether the electrode slope of the online pH meter is within the normal range. If the electrode slope is not within the normal range, it is diagnosed as an electrode slope offset fault; otherwise, it is diagnosed as an electrode zero drift fault and the fault diagnosis type is output.

[0070] In this example, the normal flow rate range is between 4 and 8 L / h. The float flowmeter can be read offline to determine whether the water sample flow rate is within the normal range;

[0071] In this example, the normal temperature range is within 25±3°C, and the temperature measured by the temperature electrode can be read offline to determine whether the water sample temperature is within the normal range;

[0072] In this example, the normal range of the slope is 90% to 100% of the theoretical slope, where the theoretical slope is 59.16 mV / pH. The electrode slope can be read offline to determine whether it is within the normal range.

[0073] The troubleshooting method for the online pH meter whose indication error is out of control range is as follows:

[0074]

[0075] In addition, the present invention application provides a computer device, characterized in that it includes a memory, a processor and a computer program stored on the memory, and the online pH meter fault detection and diagnosis program is configured to implement any of the methods in the above embodiments.

[0076] The present invention application provides a computer-readable storage medium having a computer program stored thereon, characterized in that when the online pH meter fault detection and diagnosis program is executed by a processor, the method described in any one of the above embodiments is implemented.

[0077] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A device for detecting and diagnosing faults of an online pH meter, characterized in that: It includes a controller (1), a standard solution (5), and a three-way electric valve (7); The water inlet of the three-way electric valve (7) is connected to an online water sample, the standard solution end of the three-way electric valve (7) is connected to a standard solution (5), and the water outlet of the three-way electric valve (7) is connected to an online pH meter (2); the water outlet of the three-way electric valve (7) is connected to the water inlet of a pH electrode (3), the pH electrode (3) is connected to the online pH meter (2), and the pH electrode (3) is arranged in a circulation pool; The controller is connected to obtain a measurement value of an online pH meter (2) and determines a fault state of the online pH meter based on the measurement value; The method for detecting and diagnosing faults of an online pH meter comprises: Obtaining a measurement value of an online pH meter and determining whether the measurement value of the online pH meter is normal according to a set operating threshold; If the measured value of the online pH meter exceeds the operating threshold, the online pH meter is self-checked; The self-test method of the online pH meter is as follows: Cut off the online measurement water path of the online pH meter, pass the standard solution into the online pH meter, obtain the standard solution measurement value of the online pH meter, and determine the error value of the online pH meter according to the measurement value of the online pH meter and the measurement value of the standard solution; Obtaining an error value of an online pH meter and determining a state of the online pH meter according to a set error threshold; If the error value is within the error threshold range, the online pH meter is not faulty; if the error value exceeds the error threshold range, the online pH meter is diagnosed for fault and the fault type is output; The fault diagnosis method of the online pH meter comprises the following steps: Step 1: Obtain the water sample flow rate of the online pH meter. When the water sample flow rate exceeds the set flow rate threshold range, the online pH meter is at a water sample flow abnormality fault. When the water sample flow rate is within the set flow threshold range, execute step 2; Step 2: Obtain the water sample temperature of the online pH meter. If the water sample temperature exceeds the set temperature threshold range, the online pH meter is at a water sample temperature abnormality fault. When the water sample temperature is within the set temperature threshold range, execute step 3; Step 3: Obtain the electrode slope of the online pH meter. When the electrode slope exceeds the set slope threshold range, the online pH meter has an electrode slope offset fault.

2. The device for online pH meter fault detection and diagnosis according to claim 1, characterized in that: The calculation method of the error value δ of the online pH table is as follows: δ=S﹣S b Where, δ is the indication error of the online pH meter, S is the measured value of the online pH meter, and S b is the measured value of the standard solution.

3. The device for online pH meter fault detection and diagnosis according to claim 1, characterized in that: Online pH meter fault types include: abnormal water sample flow fault, abnormal water sample temperature fault, electrode slope offset fault and electrode zero drift fault.

4. The device for online pH meter fault detection and diagnosis according to claim 1, characterized in that: The standard solution end of the three-way electric valve (7) is connected to the standard solution (5) via a peristaltic pump (6).

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