An online monitoring method for the sealing performance of an ultrasonic gas meter housing

Abstract

The present invention relates to an on-line monitoring method for the airtightness of an ultrasonic gas meter housing. After setting key parameters in the initialization stage, an intelligent algorithm integrated in the MCU processor monitors pressure sensors A and B in real time. It utilizes the pressure difference generated by the intake pipes with different through-diameters at both ends and combines the flow data measured by the metering module, and compares it with the set threshold value to determine whether an abnormality occurs and whether it is necessary to dynamically adjust the leakage pressure difference threshold value by using the recursive least squares method to adapt to environmental changes. If an abnormality is detected, the MCU will control the valve module to close the valve and report the abnormality information to the remote master station system via the remote transmission module; if it is determined that the threshold value needs to be updated, the MCU will adjust the threshold value according to the collected data and perform a final value judgment on the updated threshold value. This method ensures the safety of users' gas consumption while reducing maintenance costs and improving the stability of the system, integrating multiple advantages such as noise suppression, dynamic adjustment, improved sensitivity and calculation efficiency.

Description

Technical Field

[0001] The present invention relates to an on-line monitoring method for the airtightness of an ultrasonic gas meter housing. Background Art

[0002] With the acceleration of the urbanization process, as an important part of clean energy, the safe and reliable supply of gas has become one of the key links in urban management. In the field of intelligent gas meters, ultrasonic gas meters, with their characteristics of high precision and non-intrusive measurement, play an important role in modern gas management systems. However, due to the special structural design of ultrasonic gas meters, during their manufacturing process, key components such as metering modules, flow channels, and valves need to be assembled inside the housing, and the housing is fixed with a hoop using sealant or gaskets to ensure overall airtightness.

[0003] Although ultrasonic gas meters have undergone strict airtightness tests before leaving the factory, in actual applications, due to uncertain factors in the production process or material processing, or improper use by users, such as improper stamping operations or hitting hard objects, there may still be leakage in the housing, resulting in economic losses. Such problems usually need to be discovered through regular inspections, increasing maintenance costs and risks.

[0004] In the prior art, the airtightness detection of gas meters usually relies on regular manual inspections or off-line detections, and it is impossible to monitor the airtight state of gas meters in real time, making it difficult to detect and handle leakage problems in a timely manner. Therefore, there is an urgent need for a technical solution that can monitor the airtightness of the gas meter housing in real time to improve the safety and reliability of gas meters. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a technical solution for an on-line monitoring method for the airtightness of an ultrasonic gas meter housing. By real-time monitoring of the pressure change at the gas inlet of the meter and the flow data of the metering module, it is possible to timely detect housing leakage or metering failure, improve the reliability and safety of the system, and reduce operation and maintenance costs.

[0006] The on-line monitoring method for the airtightness of an ultrasonic gas meter housing is characterized in that:

[0007] 1) The gas inlet pipeline of the gas meter is set as an inlet pipeline with different diameters at both ends. The end with a larger diameter is connected to the gas inlet, and the end with a smaller diameter is exposed in the base meter cavity;

[0008] 2) A pressure sensor A is set at the end with a larger diameter of the inlet pipeline, and a pressure sensor B is set at the end with a smaller diameter of the inlet pipeline. The Bernoulli principle is used to create a pressure difference at different diameters to determine whether gas enters the gas meter.

[0009] 3) Initialize parameters. The gas meter MCU processor monitors pressure sensor A and pressure sensor B in real time. By using the pressure difference generated by the intake pipes with different diameters at both ends and combining with the flow data measured by the metering module, it compares with the set threshold value to determine whether an abnormality occurs and whether it is necessary to dynamically adjust the leakage pressure difference threshold using the recursive least squares method to adapt to environmental changes;

[0010] 4) If an abnormality is detected, the MCU processor will control the valve module to close the valve and report the abnormality information to the remote master station system via the remote transmission module; if it is determined that the threshold needs to be updated, the MCU processor will adjust the threshold according to the collected data and perform a final value judgment on the updated threshold.

[0011] The described on-line monitoring method for the shell sealing performance of an ultrasonic gas meter is characterized in that the specific steps are as follows:

[0012] S1: Initialize parameters: The MCU processor starts, and sets the initial leakage pressure difference threshold ΔP s (0) = 20Pa, the initial covariance matrix F0 = 1000I, the forgetting factor λ = 0.99, the self-detection duration T = 10min, the minimum threshold of the shell leakage pressure difference under the user gas consumption state = 5pa, the maximum threshold of the shell leakage pressure difference under the user gas consumption state = 10pa, the pressure difference threshold ΔP corresponding to the starting flow of the metering module d Set according to the meter specifications;

[0013] S2: Collect data to determine whether the user is using gas: The MCU processor collects the pressure values of pressure sensor A and pressure sensor B and the instantaneous flow data of the metering module every 2 seconds according to the time data provided by the clock module. The data collected for the i-th time are respectively 、 and , calculate ; if , (x) is the leakage pressure difference threshold for judgment, then the MCU processor determines that the user is not using gas and executes step S3; if <ΔP i <ΔP d , then execute step S4; if ΔP d ≤ΔP i , then the MCU processor determines that the user is using gas and executes step S6;

[0014] S3: Judge whether a leakage abnormality occurs: Continue to judge according to the data collected for the i-th time. If and , then the MCU processor judges that there is no abnormal situation; if And , the MCU processor determines that a leakage anomaly has occurred, closes the valve of the valve module, and reports the anomaly information to the master station system through the remote transmission module;

[0015] S4: Determine whether there is a meter anomaly: Continue to judge according to the data collected in the i-th time. If q i = 0, the MCU processor determines that there is no anomaly in the meter, and needs to update the leakage pressure difference threshold, and execute step S5; if q i > 0, the MCU processor determines that the meter metering module has failed, closes the valve of the valve module, and reports the anomaly information to the master station system through the remote transmission module;

[0016] S5: Update the leakage pressure difference threshold: After determining that there is an anomaly, the MCU processor calculates and updates the leakage pressure difference threshold in real time, and uses the recursive least squares method to update the leakage pressure difference threshold; the number of times of each update is recorded as x (x = 1, 2, 3,...), where x is the number of steps in the recursive process;

[0017] The MCU processor respectively collects the pressure values P Ai and P Bi through the pressure sensor A and the pressure sensor B, and calculates the residual value :

[0018] , r is a 1*2 row vector

[0019] Calculate the gain matrix Kx:

[0020] Among them, is the column vector composed of the measurement data of the pressure sensor A and the pressure sensor B;

[0021] Update the covariance matrix: ;

[0022] Update the leakage pressure difference threshold : ;

[0023] Execute the final value judgment step S51 on the calculated data;

[0024] S51: Final value judgment of the leakage pressure difference threshold: If and When, M is the final value judgment ratio threshold of ΔPs, default 0.01%; m is the final value judgment measurement threshold of ΔPs, default 0.1 pa, the MCU processor determines that the current is the threshold value that can detect all minor leakage situations in the current environment, and the update of the leakage pressure difference threshold terminates; the clock module starts timing, and it is only allowed to execute step S5 after 3 months and will clear the originally reserved and it starts to recursively search for a suitable value starting from the initial preset value ; If or , the MCU processor determines that the current does not cover all leakage situations in the current environment and allows execution when S5 needs to be executed next time;

[0025] S6: When the user is using gas, determine whether there is an abnormality in the meter: continue to judge according to the data collected for the i-th time. If q i = 0, the MCU processor determines that the meter has a metering failure, controls the valve module to close the valve, and reports the abnormality information to the master station system through the remote transmission module; if q i > 0, the MCU processor determines that there may be a leakage situation and executes step S61;

[0026] S61: Perform self-detection: Within the T time, the meter continuously monitors the data of pressure sensor A and pressure sensor B, and calculates , is the pressure value of pressure sensor A collected for the j-th time during the self-detection process, is the pressure value of pressure sensor B collected for the j-th time during the self-detection process, is the pressure difference between A and B when the data is collected for the j-th time during the self-detection process; if there is always within the T time, it is determined that there is a leakage in the housing. At this time, the MCU processor controls the valve module to close the valve and reports it to the master station system through the remote transmission module; if there is always within the T time, the MCU processor determines that there is no abnormality; if appears within the T time, the MCU processor determines that this situation is caused by the change in the intake air volume during normal gas use by the user. The clock module re-times T, and the MCU processor re-executes step S61.

[0027] The beneficial effects of the present invention:

[0028] (1) Noise suppression: The gain matrix can effectively reduce the influence of sensor noise on the estimation of the leakage pressure difference threshold and improve the detection accuracy;

[0029] (2) Dynamic adjustment: Through the recursive algorithm, the gain matrix can update the leakage pressure difference threshold in real time, adapt to environmental and flow changes, improve the system stability, and reduce false alarms;

[0030] (3) Improve sensitivity: Accurately estimate the leakage pressure difference threshold, which helps to detect small leaks and avoid missed judgments; Computational efficiency: The gain matrix algorithm is relatively simple, with a small amount of calculation, and is suitable for rapid execution in the MCU real-time system;

[0031] (4) Reduce resource waste: By judging the final value of the leakage pressure difference threshold, the waste of MCU computing power resources is eliminated, and the overall revenue and service life of the system are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a diagram of the system position relationship;

[0033] Figure 2 It is a schematic diagram of the intake pipe with different diameters;

[0034] Figure 3 It is a schematic diagram of the work flow;

[0035] Figure 4 It is a logic diagram for abnormal judgment. SPECIFIC IMPLEMENTATION MANNER

[0036] The present invention will be further described below in conjunction with the accompanying drawings of the specification:

[0037] Figure 1 It is a diagram of the system position relationship, showing the position relationship of components such as pressure sensors A and B, the MCU processor, and the ultrasonic metering module;

[0038] Figure 2 It is a schematic diagram of the intake pipe with different diameters, showing the positions of the large-diameter and small-diameter intake pipes and the principle of generating pressure difference;

[0039] Figure 3 It is a schematic diagram of the work flow, showing the complete process from initialization to abnormal judgment;

[0040] Figure 4 It is a logic diagram for abnormal judgment, showing how to judge the shell leakage or the failure of the metering module under different conditions.

[0041] In order to effectively address the problems of untimely and inaccurate monitoring of the ultrasonic gas meter in terms of shell leakage or metering module failure, this solution proposes a method of comprehensive detection using eight key components: pressure sensor A, pressure sensor B, MCU processor, ultrasonic metering module, intake pipe with different diameters at both ends, valve module, remote transmission module, and clock module.

[0042]

[0043] The following are the physical quantities and their definitions that appear in this application:

[0044] : The pressure value of pressure sensor A collected for the i-th time on the same day

[0045] : The pressure value of pressure sensor B collected for the i-th time on the same day

[0046] : The flow rate of the i-th collection of the metering module on the same day

[0047] : The pressure difference between A and B when collecting data for the i-th time on the same day

[0048] (x): The leakage pressure difference threshold for judgment

[0049] T: The self-detection duration, default value is 10 minutes

[0050] : The pressure value of pressure sensor A collected for the j-th time during the self-detection process

[0051] : The pressure value of pressure sensor B collected for the j-th time during the self-detection process

[0052] : The flow rate of the metering module collected for the j-th time during the self-detection process

[0053] : The pressure difference between A and B when collecting data for the j-th time during the self-detection process

[0054] : Represents the maximum threshold of the difference in the shell leakage pressure difference under the user's gas-using state

[0055] : Represents the minimum threshold of the difference in the shell leakage pressure difference under the user's gas-using state

[0056] K x : The updated gain matrix

[0057] e x : The updated residual value

[0058] λ: Forgetting factor, used to limit the weight of past values

[0059] F x : The updated covariance matrix

[0060] M: The final value judgment ratio threshold of ΔPs, default is 0.01%

[0061] m: The final value judgment measurement threshold of ΔPs, default is 0.1pa

[0062] ΔP d : The pressure difference threshold corresponding to the starting flow rate of the metering module.

[0063] An on-line monitoring method for the sealing performance of the ultrasonic gas meter housing of the present invention: 1) Set the gas inlet pipeline of the gas meter as an inlet pipeline with different diameters at both ends. The end with a larger diameter is connected to the gas inlet, and the end with a smaller diameter is exposed in the base meter cavity; 2) Set pressure sensor A at the end with a larger diameter of the inlet pipeline, and set pressure sensor B at the end with a smaller diameter of the inlet pipeline. Use Bernoulli's principle to create a pressure difference at different diameters to determine whether gas enters the gas meter; 3) Initialize the parameters. The MCU processor of the gas meter monitors pressure sensor A and pressure sensor B in real time. Use the pressure difference generated by the inlet pipeline with different diameters at both ends and combine the flow data measured by the metering module to compare with the set threshold to determine whether an abnormality occurs and whether it is necessary to dynamically adjust the leakage pressure difference threshold using the recursive least squares method to adapt to environmental changes; 4) If an abnormality is detected, the MCU processor will control the valve module to close the valve and report the abnormality information to the remote master station system via the remote transmission module; if it is determined that the threshold needs to be updated, the MCU processor will adjust the threshold according to the collected data and perform a final value judgment on the updated threshold.

[0064] The specific steps of the present invention are as follows:

[0065] S1 Initialize parameters: The MCU processor starts, and sets the initial leakage pressure difference threshold ΔP s (0) = 20 Pa (default value), the initial covariance matrix F0 = 1000I (default value, I is a 2*2 identity matrix), the forgetting factor λ = 0.99 (default value), the self-detection duration T = 10 min (default value), = 5 pa (default value), = 10 pa (default value), ΔP d Set according to the meter specifications.

[0066] S2 Collect data to determine whether the user is using gas: The MCU processor collects the pressure values of pressure sensors A and B and the instantaneous flow data of the metering module every 2 seconds according to the time data provided by the clock module. The data collected for the i-th time are respectively 、 and , calculate . If , the MCU processor determines that the user is not using gas and executes step S3; if , execute step S4; if ΔP d ≤ΔP i , the MCU processor determines that the user is using gas and executes step S6.

[0067] S3 Determine whether a leakage abnormality occurs: Continue to judge according to the data collected for the i-th time. If and , the MCU processor determines that there is no abnormal situation; if and , the MCU processor determines that a leakage anomaly has occurred, closes the valve module, and reports the anomaly information to the master station system through the remote transmission module.

[0068] S4 Determine whether there is an anomaly in the meter: Continue to judge based on the data collected in the i-th time. If q i = 0, the MCU processor determines that there is no anomaly in the meter, needs to update the leakage pressure difference threshold, and executes step S5; if q i > 0, the MCU processor determines that the meter measurement module has failed, closes the valve module, and reports the anomaly information to the master station system through the remote transmission module.

[0069] S5 Update the leakage pressure difference threshold: After determining that there is an anomaly, the MCU processor calculates and updates the leakage pressure difference threshold in real time, and uses the recursive least squares method (RLS) to update the leakage pressure difference threshold; the number of each update is recorded as x (x = 1, 2, 3,...), where x is the number of steps in the recursive process;

[0070] The MCU processor respectively collects the pressure values P Ai and P Bi through pressure sensors A and B, and calculates the residual value:

[0071] (r is a 1*2 row vector)

[0072] Calculate the gain matrix Kx:

[0073] ;

[0074] Among them, is the column vector composed of the measurement data of pressure sensors A and B;

[0075] Update the covariance matrix:

[0076] ;

[0077] Update the leakage pressure difference threshold : ;

[0078] Execute the final value judgment step S51 on the calculated data.

[0079] S51 Final value judgment of the leakage pressure difference threshold: If and when, the MCU processor judges the current is the threshold value for detecting all minor leakage situations in this environment, and the update of the leakage pressure difference threshold terminates. The clock module starts timing, and only after 3 months is it allowed to execute step S5 and the originally reserved will be cleared, and it starts to recursively find a suitable again from the initial preset value ; if or , the MCU processor determines that the current has not covered all leakage situations in this environment and is allowed to execute when S5 needs to be executed next time.

[0080] S6 determines whether there is an abnormal meter during user gas consumption: continue to judge according to the data collected for the i-th time. If q i = 0, the MCU processor determines that the meter has a metering failure, controls the valve module to close the valve, and reports the abnormal information to the master station system through the remote transmission module; if q i > 0, the MCU processor determines that there may be a leakage situation and executes step S61.

[0081] S61 performs self-detection: within the T time, the meter continuously monitors the data of two pressure sensors and calculates . If there is always within the T time, it can be determined that the housing has a leakage. At this time, the MCU processor controls the valve module to close the valve and reports to the master station system through the remote transmission module; if there is always within the T time, the MCU processor determines that there is no abnormality; if appears within the T time, the MCU processor determines that this situation is due to the change in the intake volume caused by the user's normal gas consumption, the clock module restarts timing for T, and the MCU processor re-executes step S61.

[0082] The present invention aims to automatically detect and diagnose possible abnormal conditions of a gas meter, such as housing leakage or metering module failure, by real-time monitoring and analyzing the flow data transmitted by pressure sensors and metering modules to the MCU.

[0083] In the initialization stage, the MCU processor sets a series of key parameters, including the initial leakage pressure difference threshold, covariance matrix, forgetting factor, and self-detection duration. These parameters are the basis for subsequent data processing and abnormal judgment. When the system is in operation, the MCU processor regularly collects data from pressure sensors and metering modules at set time intervals. It uses this data to calculate the pressure difference at pressure sensors A and B and evaluate whether there are potential problems. For each set of collected data, the MCU processor performs a series of logical judgments to determine whether it is necessary to update the leakage pressure difference threshold (x) or take further actions, such as closing the valve or sending an alarm.

[0084] In particular, when the pressure difference between pressure sensors A and B is detected to be less than the leakage pressure difference threshold and the metering module shows that the instantaneous flow rate is zero, the MCU processor will, according to preset conditions, (x) be iteratively updated to more accurately adapt to the leakage detection requirements in the current environment.

[0085] In addition, to improve the detection accuracy and reduce the false alarm rate, the present invention also introduces a mechanism for dynamically adjusting the threshold. This mechanism allows the system to automatically adjust the sensitivity of leakage detection based on the data performance over a long period of time, ensuring high-efficiency monitoring performance even when environmental conditions change. Every quarter, the system will recalibrate the leakage pressure difference threshold to account for the impact of seasonal changes.

[0086] The present invention can effectively ensure the gas-using safety of users, while reducing the maintenance cost and improving the stability of the system, and integrates multiple advantages such as noise suppression, dynamic adjustment, improved sensitivity and calculation efficiency.

Claims

1. An online monitoring method for the sealing performance of an ultrasonic gas meter housing, characterized in that: 1) The gas meter air inlet pipe is set to have different diameters at both ends, with the larger diameter end connected to the air inlet and the smaller diameter end exposed in the base meter cavity; 2) A pressure sensor A is installed at the end with a larger diameter of the air intake pipe, and a pressure sensor B is installed at the end with a smaller diameter of the air intake pipe. The Bernoulli principle is used to create a pressure difference at different diameters to determine whether gas has entered the gas meter; 3) Initialize parameters. The MCU processor of the gas meter monitors pressure sensor A and pressure sensor B in real time. It uses the pressure difference generated by the intake pipes with different diameters at both ends and combines it with the flow data measured by the metering module to compare it with the set threshold to determine whether there is an abnormality and whether it is necessary to use the recursive least squares method to dynamically adjust the leakage pressure difference threshold to adapt to environmental changes. 4) If an abnormality is detected, the MCU processor will control the valve module to close the valve and report the abnormal information to the remote master station system via the remote transmission module; if it is determined that the threshold needs to be updated, the MCU processor will adjust the threshold based on the collected data and make a final value judgment on the updated threshold.

2. The method for online monitoring of the sealing performance of an ultrasonic gas meter housing according to claim 1, characterized in that The specific steps are as follows: S1: Initialization parameters: MCU processor starts, sets the initial leakage pressure difference threshold ΔP s (0) = 20Pa, initial covariance matrix F0 = 1000I, forgetting factor λ = 0.99, self-detection time T = 10min, minimum threshold of the shell leakage pressure difference under the user gas state =5pa, the maximum threshold of the shell leakage pressure difference when the user is using gas =10pa, the pressure difference threshold ΔP corresponding to the starting flow of the metering module d Set according to the meter specifications; S2: Collect data to determine whether the user is using gas: The MCU processor collects the pressure values ​​of pressure sensor A and pressure sensor B and the instantaneous flow data of the metering module every 2 seconds according to the time data provided by the clock module. The data collected for the i-th time are , and ,calculate ;like , (x) is the leakage pressure difference threshold used for judgment, the MCU processor determines that the user does not use gas and executes step S3; if <ΔP i <ΔP d , then execute step S4; if ΔP d ≤ΔP i , the MCU processor determines that the user is using gas and executes step S6; S3: Determine whether leakage occurs: Continue to determine based on the data collected for the i-th time. If and , the MCU processor determines that there is no abnormality; if and , the MCU processor determines that a leakage abnormality occurs, controls the valve module to close the valve, and reports the abnormal information to the main station system through the remote transmission module; S4: Determine whether the meter is abnormal: Continue to judge based on the data collected for the i-th time. If q i =0, the MCU processor determines that the meter has no abnormality and needs to update the leakage pressure difference threshold, and executes step S5; if q i >0, the MCU processor determines that the metering module of the meter fails, controls the valve module to close the valve, and reports the abnormal information to the main station system through the remote transmission module; S5: Update leakage pressure difference threshold: After determining that there is an abnormality, the MCU processor calculates and updates the leakage pressure difference threshold in real time, and uses the recursive least squares method to update the leakage pressure difference threshold; the number of updates each time is recorded as x, x=1,2,3,…, where x is the number of steps in the recursive process; The MCU processor collects the pressure values ​​P through pressure sensor A and pressure sensor B respectively. Ai and P Bi , and calculate the residual value : , r is a 1*2 row vector Calculate the gain matrix Kx: in, is a column vector composed of the measurement data of pressure sensor A and pressure sensor B; Update the covariance matrix: ; Update the leakage pressure difference threshold : ; Performing final value determination step S51 on the calculated data; S51: Leakage pressure difference threshold final value judgment: If and When M is the ratio threshold for judging the final value of ΔPs, the default value is 0.01%; m is the measurement threshold for judging the final value of ΔPs, the default value is 0.1pa, and the MCU processor judges the is the threshold that can detect all small leaks in the current environment, and the leakage pressure difference threshold update is terminated; the clock module starts timing, and step S5 is allowed to be executed after 3 months and the originally retained , which is set from the initial preset value Start recursion to find the right one ;like or When the MCU processor determines the All leaks in the current environment have not been covered yet, and S5 is allowed to be executed the next time it is needed; S6: When the user is using gas, determine whether the meter is abnormal: Continue to determine based on the data collected for the i-th time. If q i =0, the MCU processor determines that the meter fails to measure, controls the valve module to close the valve, and reports the abnormal information to the main station system through the remote transmission module; if q i >0, the MCU processor determines that there may be a leakage and executes step S61; S61: Perform self-test: During T time, the meter continuously monitors the data of pressure sensor A and pressure sensor B, and calculates , The pressure value of pressure sensor A collected for the jth time during the self-test process, The pressure value of pressure sensor B collected for the jth time during the self-test process, is the pressure difference between A and B when collecting data for the jth time during the self-test process; if , it is judged that the shell has leakage. At this time, the MCU processor controls the valve module to close the valve, and the remote transmission module reports to the main station system; if there is always leakage within T time , the MCU processor determines that there is no abnormality; if it occurs within T time , the MCU processor determines that this is a change in air intake caused by normal gas usage by the user, the clock module resets the time T, and the MCU processor re-executes step S61.

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