Method for determining micro-leakage based on diaphragm gas meter

Abstract

This invention relates to the field of gas flow monitoring technology, and discloses a micro-leakage determination method based on a diaphragm gas meter, comprising the following steps: Step 1, if a user's pulse signal is collected at the current moment, the current moment is stored in a queue, and the moments in the queue are maintained within a time window; Step 2, if the number of moments stored in the queue is within a first threshold range, the first minute within the time window is marked as a micro-leakage moment; otherwise, proceed to Step 3; Step 3, based on the state change triggered by the rotating gear of the gas meter, determine whether the user has zero flow at the current moment. If so, the gas meter does not have a micro-leakage; if not, the first minute within the time window is marked as a micro-leakage moment; Step 4, repeat steps 1 to 3. When the number of marked micro-leakage moments meets a set condition, it is determined that the user has a leakage risk. The purpose of this invention is to balance the sensitivity and accuracy of micro-leakage detection.

Description

Technical Field

[0001] This invention relates to the field of gas flow monitoring technology, and in particular to a method for determining micro-leakage based on a diaphragm gas meter. Background Technology

[0002] Micro-flow gas leakage is a critical safety hazard that requires close monitoring during gas usage. When the volumetric concentration of gas in a confined space accumulates to the lower explosive limit (5% VOL), it can trigger an explosion, causing unacceptable casualties and property damage. For residential and small commercial users, the most direct approach is to install combustible gas detectors to monitor gas concentration in real time. When the threshold is reached, an audible and visual alarm is triggered, activating the fire suppression system for further action. However, this method relies on human intervention, and the safety hazard cannot be eliminated promptly when no one is home or when external personnel cannot enter.

[0003] As a supplementary detection method, more and more gas meters are beginning to incorporate micro-flow detection functions. Taking residential users as an example, if the flow rate Q consistently remains between 5L / h and 25L / h, it is considered a micro-flow leak. In this case, the gas supply is cut off by closing the gas meter's built-in valve to prevent further leakage. However, since diaphragm gas meters use volumetric measurement, existing mature technologies utilize Hall effect sensors to collect the rotation of mechanical gears. Each complete rotation of the gear generates a pulse signal, representing an accumulated flow of 10L. Taking a stable instantaneous flow rate of 5L / h as an example, the accumulated flow rate reconstructed based on the Hall effect sensor signal is as follows: Figure 1 As shown, it can be seen that the cumulative flow collected by the Hall sensor only changes once every 10L, and the original instantaneous flow information is masked, making it impossible to determine whether there is a real micro-flow leakage.

[0004] Based on the above principle, most gas meters determine whether a micro-flow leak occurs by calculating the interval between two pulses. However, considering a relatively extreme case, if the gas meter detects an interval of 2 hours between two pulses, it might arbitrarily conclude that these 2 hours constitute a micro-flow leak, meaning a micro-flow of 10L / 2h = 5L / h continuously flows through the gas meter. However, in actual use, a user might use the water heater at a flow rate of 2000L / h (e.g., for washing hands) for the first 10 seconds, consuming approximately 5.6L of accumulated flow; then experience zero flow during the middle period; and finally use the water heater again in the last 10 seconds. In this case, the Hall sensor would collect data such as... Figure 2 The flow rate shown, but with Figure 1 The similarity between the two can lead to misjudgments of micro-flow leaks, causing unnecessary valve closure operations. Therefore, balancing the sensitivity and accuracy of micro-flow leak detection remains a pressing issue. Summary of the Invention

[0005] The purpose of this invention is to balance the sensitivity and accuracy of micro-flow leakage detection and to provide a micro-leakage determination method based on a diaphragm gas meter.

[0006] To achieve the above-mentioned objectives, the embodiments of the present invention provide the following technical solutions:

[0007] The method for determining micro-leakage based on diaphragm gas meters includes the following steps:

[0008] Step 1: If a user's pulse signal is collected at the current moment, the current moment is stored in the queue, and the moment in the queue is kept within the time window.

[0009] Step 2: If the number of moments stored in the queue is within the first threshold range, then mark the first minute within the time window as the micro-flow leakage moment; otherwise, proceed to step 3.

[0010] Step 3: Based on the state change triggered by the rotating gear of the gas meter, determine whether the user has zero flow at the current moment. If so, the gas meter does not have a micro-flow leak; if not, mark the first minute of the time window as the micro-flow leak moment.

[0011] Step 4: Repeat steps 1 to 3. When the number of marked micro-flow leakage moments meets the set conditions, it is determined that the user has a leakage risk.

[0012] Furthermore, step 1 specifically includes the following steps:

[0013] Let t be the time from when the gas meter was powered on to the current time.

[0014] If a pulse signal is acquired at the current moment, the current moment t is stored in queue D;

[0015] When t is greater than the width w of the time window, iterate through any time t0 in the queue D. If t0 ≤ tw, remove t0 from the queue D so that the time in the queue D is kept within the time window of width w.

[0016] Furthermore, in step 2, the first threshold range is [1, N], where,

[0017]

[0018]

[0019] w is the width of the time window, in min; V is the pulse volume, in L; Qmin is the minimum flow rate, in L / h; Tmin is the pulse signal time interval corresponding to the minimum flow rate Qmin, in min.

[0020] Furthermore, step 2, which marks the first minute within the time window as the moment of micro-flow leakage, specifically includes:

[0021] If the number of times stored in queue D is equal to 1, then time t-w+1 is marked as the micro-flow leakage time;

[0022] If the number of times stored in queue D is greater than 1 and less than or equal to N, and the difference between any two adjacent times in queue D is greater than or equal to Tmin, then time t-w+1 is marked as the micro-flow leakage time.

[0023] In step 3, a permanent magnet is embedded in the rotating gear, and two Hall effect devices A and B, symmetrical to the rotating gear, are set on the PCB board. The rotating gear can identify four states in one rotation cycle, and one cycle is 360 degrees.

[0024] State ①: When the permanent magnet rotates from 360-m degrees to m degrees, Hall device A can detect the permanent magnet and trigger a low level, while Hall device B cannot detect the permanent magnet and triggers a high level.

[0025] State ②: When the permanent magnet rotates from m degrees to 180-m degrees, Hall device A cannot detect the permanent magnet and triggers a high level, and Hall device B cannot detect the permanent magnet and triggers a high level.

[0026] State ③: When the permanent magnet rotates from 180-m degrees to 180+m degrees, Hall device A cannot detect the permanent magnet and triggers a high level, while Hall device B can detect the permanent magnet and triggers a low level.

[0027] State ④: When the permanent magnet rotates from 180+m degrees to 360-m degrees, Hall device A cannot detect the permanent magnet and triggers a high level, and Hall device B cannot detect the permanent magnet and triggers a high level.

[0028] Where 15 ≤ m ≤ 20 degrees.

[0029] Furthermore, step 3, which involves determining whether the user's gas flow is zero at the current moment based on the state change triggered by the rotating gear of the gas meter, specifically includes:

[0030] Let tu be the time of the most recent state change of the rotating gear, and t be the current time;

[0031] If the changed state is ① or ③, and if t-tu ≥ m / π*Ts, then the user is determined to have zero traffic at the current time t; otherwise, mark time t-w+1 as the time of micro-traffic leakage.

[0032] If the changed state is ② or ④, and if t-tu ≥ (180-2m) / 2π*Ts, then the user is determined to have zero flow at the current time t; otherwise, mark time t-w+1 as the time of micro-flow leakage.

[0033] Where Ts = V / Qs, V is the pulse volume in L; Qs is the starting flow rate in L / h; and Ts is the pulse signal time interval corresponding to the starting flow rate Qs in min.

[0034] Furthermore, in step 4, the specific steps for determining that a user has a leakage risk when the number of marked micro-flow leakage moments meets the set conditions include:

[0035] Let t be the time from when the gas meter was powered on to the current time.

[0036] The specified time for micro-flow leakage is set as y;

[0037] Let x be the cumulative time point for the micro-flow leakage;

[0038] If the number of marked micro-flow leakage moments is greater than or equal to x within the time period from ty to t, it is determined that the user has a leakage risk, the built-in valve of the gas meter is closed, and an alarm message is reported.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention designs a micro-flow leakage determination method based on time window. By setting a permanent magnet on the rotating gear and symmetrically setting two Hall devices, users with zero flow are accurately excluded, reducing the probability of false judgment. Finally, the cumulative time is used to determine whether there is a risk of micro-leakage. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 Background technology: Schematic diagram of a traditional diaphragm gas meter for measuring cumulative flow;

[0042] Figure 2 Background Technology: A schematic diagram of a traditional diaphragm gas meter that measures cumulative flow by calculating the interval between two pulses;

[0043] Figure 3 This is a flowchart of the method of the present invention;

[0044] Figure 4This is a schematic diagram illustrating four states of the rotating gear according to an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the pulse signal according to an embodiment of the present invention. Figure 5 (a) in the diagram shows a time window with a width of w containing only one pulse signal. Figure 5 (b) in the figure is a schematic diagram of 5 pulse signals within a time window with a width of w. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0047] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance, or suggesting any such actual relationship or order between these entities or operations. Additionally, the terms "connected," "linked," etc., can refer to a direct connection between elements, components, modules, etc., or an indirect connection via other elements, components, modules, etc.

[0048] Example 1:

[0049] First, determine the basic parameters: starting flow rate Qs = 5 L / h, minimum range flow rate Qmin = 25 L / h, and pulse volume V = 10 L. When the mechanical process of the gas meter changes, the corresponding basic parameters should also change. Based on the above basic parameters, the corresponding pulse interval times are: time interval Ts = V / Qs = 120 min for Qs flow rate, and time interval Tmin = V / Qmin = 24 min for Qmin flow rate.

[0050] When a diaphragm gas meter detects flow rate, if the flow rate is zero, it can be determined that the user is definitely not leaking. Therefore, it is only necessary to determine whether a leak exists for users whose flow rate is not zero. It is known that when gas consumption is continuously at the starting flow rate Qs, a pulse signal is generated every Ts. When the time interval between two adjacent pulse signals is greater than Ts, it indicates that the user definitely has zero flow, and it can be determined that the user is definitely not leaking. Therefore, the user's accumulated flow can be reset to zero, meaning there is no need to use the accumulated flow to determine whether a leak exists. However, depending on the gas meter design and manufacturing process, a longer Ts may not be able to wait for the reset in actual use, leading to misjudgment of the duration of micro-flow. To solve this problem, this solution embeds a permanent magnet on the rotating gear and sets two Hall effect devices symmetrically opposite to the rotating gear on the PCB board. Figure 4 As shown, A and B are two Hall effect devices mounted on a PCB board, and a permanent magnet is embedded in the rotating gear. When the rotating gear rotates clockwise, one 360-degree rotation cycle can identify four states (m=18 degrees):

[0051] State ①: When the permanent magnet rotates from 342 degrees to 18 degrees, Hall device A can detect the permanent magnet, while Hall device B cannot detect the permanent magnet. That is, Hall device A is attracted and Hall device B is disconnected. Hall device A is triggered with a low level "0" and Hall device B is triggered with a high level "1".

[0052] State ②: When the permanent magnet rotates from 18 degrees to 162 degrees, Hall device A cannot detect the permanent magnet, and Hall device B also cannot detect the permanent magnet. That is, Hall device A is disconnected and Hall device B is disconnected. Then Hall device A triggers a high level "1" and Hall device B triggers a high level "1".

[0053] State ③: When the permanent magnet rotates from 162 degrees to 198 degrees, Hall device A cannot detect the permanent magnet, while Hall device B can detect the permanent magnet. That is, Hall device A is disconnected and Hall device B is attracted. Hall device A is triggered with a high level "1" and Hall device B is triggered with a low level "0".

[0054] State 4: When the permanent magnet rotates from 198 degrees to 342 degrees, Hall device A cannot detect the permanent magnet, and Hall device B also cannot detect the permanent magnet. That is, Hall device A is disconnected and Hall device B is disconnected. Then Hall device A triggers a high level "1" and Hall device B triggers a high level "1".

[0055] It is easy to understand that when the permanent magnet rotates 18 degrees (0.2π) to the left and right of Hall device A with respect to Hall device A as the center, it can be recognized by Hall device A; similarly, when the permanent magnet rotates 18 degrees (0.2π) to the left and right of Hall device B with respect to Hall device B as the center, it can be recognized by Hall device B. This solution is not limited to the 18-degree implementation method; the angle m can be changed according to the actual application scenario or the different types of Hall devices.

[0056] With the above four states designed, during the operation of the gas meter, it is possible to determine whether the user has zero flow using any of the following methods:

[0057] (1) Start timing when entering state ①. If state ② is not entered after 0.2π / 2π*Ts=12min, it is determined to be zero flow.

[0058] (2) Start timing when entering state ②. If state ③ is not entered after (π-0.2π) / 2π*Ts=48min, it is determined to be zero flow.

[0059] (3) Start timing when entering state ③. If state ④ is not entered after 0.2π / 2π*Ts=12min, it is determined to be zero flow.

[0060] (4) Start timing when entering state ④. If state ① is not entered after (π-0.2π) / 2π*Ts=48min, it is determined to be zero flow.

[0061] If any of the above methods determines that a user has zero data usage, then the user is definitely not experiencing any data leakage, and their accumulated data usage can be reset to zero. If the user does not have zero data usage, then proceed to the next step.

[0062] It is known that a gas meter generates a pulse signal every 10L of flow (meaning that when the gas consumption is continuously at the starting flow rate Qs, 10L is reached every Ts). Currently, existing smart gas meters in the industry typically do not consider the correlation between the occurrence of the pulse signal when determining micro-flow leaks; they almost only consider the time interval between two pulse signals. If the time interval T between two pulse signals satisfies Tmin ≤ T ≤ Ts, then the gas consumption pattern for the current period is judged to be a micro-flow leak. This solution, based on the concept of a digital filter, uses the pulse signal acquisition data from the past 120 minutes to infer whether there is a micro-flow leak at the current time point, thereby improving the confidence level of the micro-flow leak determination.

[0063] Within a time window of 120 minutes past the current time point (i.e., the width w of the time window is 120 minutes), the pulse signal images corresponding to the two typical micro-flow leakage are as follows: Figure 5 As shown, Figure 5Image (a) shows an image where the number of pulse signals within the time window is 1. Figure 5 Image (b) shows an image with 5 pulse signals within the time window. This means that when the number of pulse signals within the time window is between 1 and 5 and their distribution is relatively uniform, the current time point is determined to be a micro-flow leakage. Furthermore, the longer the time window width, the higher the reliability of the judgment, but the higher the overall judgment delay. Therefore, this scheme preferably uses a time window width of 120 minutes.

[0064] Based on the above idea, let t be the total number of minutes from when the gas meter is powered on to the current time. The steps for determining micro-flow leakage based on a time window with a width of w=120min are as follows:

[0065] (1) When t < 120 min, continuously record the pulse signal acquisition.

[0066] (2) When t≥120min, check the pulse signal acquisition of the time window (t-120,t) in the past 120min. If the number of pulse signals N in the time window satisfies 1≤N≤5, and the time interval T between each two adjacent pulse signals in the time window satisfies 24min≤T≤120min, then mark the time of t-120+1min as micro-flow leakage.

[0067] (3) If the cumulative number of times marked as micro-flow leakage exceeds the set threshold within a specified time, such as exceeding 24 hours (1440 minutes) within 15 days (21600 minutes), then the user is deemed to have a leakage risk. The built-in valve of the gas meter should be closed, and an alarm message should be reported to the management platform. In other words, if the user has been marked as having micro-flow leakage at least 1440 times in the past 15 days, then the user is deemed to have a leakage risk.

[0068] Based on the above principles, this invention is implemented through the following steps, as follows: Figure 3 As shown, this invention proposes a micro-leakage detection method based on a diaphragm gas meter. First, the following parameters are determined according to the design and manufacturing process of the gas meter:

[0069] The pulse volume is V, typically V = 10L;

[0070] The starting flow rate is Qs, which is typically Qs = 5 L / h;

[0071] The pulse signal time interval corresponding to the starting flow rate Qs is Ts, which is usually Ts=V / Qs=120min;

[0072] The minimum flow rate is Qmin, which is usually Qmin = 25 L / h;

[0073] The pulse signal time interval corresponding to the minimum range flow rate Qmin is Tmin, which is usually Tmin = V / Qmin = 24min;

[0074] When the rotating gear rotates, the longest continuous radian of states ① and ③ is rad1, and usually rad1 = 0.2π;

[0075] When the rotating gear is rotating, the longest continuous radian of states ② and ④ is rad2, and usually rad2 = 0.8π;

[0076] The width of the time window is w, usually w=Ts=120min;

[0077] The specified time y for micro-flow leakage is usually y = 15 * 24 * 60 = 21600 min;

[0078] The cumulative time x for micro-flow leakage is typically x = 24 * 60 = 1440 min;

[0079] Let t be the time from power-on of the gas meter to the current time; maintenance queue D stores the pulse signal acquisition times within w minutes; maintenance queue E stores the times when multiple pulse signals are acquired within w minutes; maintenance queue F stores the time of micro-flow leakage; define the interruption time of the last triggered state change of the rotating gear as tu, and the changed state as u (u=1,2,3,4, u=1 represents state ①, u=2 represents state ②, u=3 represents state ③, u=4 represents state ④). This method is executed every minute, and the method includes the following steps:

[0080] Step 1: If a pulse signal is acquired at the current moment, the current moment is stored in the queue, and the moment in the queue is kept within the time window.

[0081] If one pulse signal is acquired at time t, execute D=D∪{t}; if multiple pulse signals are acquired at time t, execute E=E∪{t}.

[0082] When t>w, iterate through any time t0 belonging to queue D or queue E. If there exists t0∈D and t0≤tw, then remove t0 from queue D; if there exists t0∈E and t0≤tw, then remove t0 from queue E.

[0083] Step 2: If the number of moments stored in the queue is within the first threshold range, then mark the first minute within the time window as the micro-flow leakage moment; otherwise, proceed to step 3.

[0084] The first threshold range is [1, N], where .

[0085] For pulse signal acquisition within the time window (tw,t], the time recorded in queue D is used. When |D|<1 or |D|>N or |E|>0, step 3 is executed. |D| represents the number of time moments in queue D.

[0086] When |D|=1, mark time t-w+1 as the time of micro-flow leakage, and execute F=F∪{t-w+1}.

[0087] When |D|>1 and |D|≤N, if the difference between any two adjacent times in queue D is greater than or equal to Tmin, then mark time t-w+1 as the micro-flow leakage time and execute F=F∪{t-w+1}.

[0088] Step 3: Based on the state change triggered by the rotating gear of the gas meter, determine whether the user has zero flow at the current moment. If so, the gas meter does not have a micro-flow leak; if not, mark the first minute of the time window as the micro-flow leak moment.

[0089] If the interruption of the rotating gear state change is triggered at time t, then tu = t, and the state is u; if the state u = 1 or u = 3, then δt = rad1 / 2π*Ts; if u = 2 or u = 4, then δt = rad2 / 2π*Ts, where δt represents the duration of the corresponding state. If t - tu ≥ δt, it is determined that the flow rate at time t is zero, and the queue F is cleared; otherwise, time t - w + 1 is marked as a micro-flow leakage time, and F = F ∪ {t - w + 1} is executed.

[0090] Step 4: Repeat steps 1 to 3. When the number of marked micro-flow leakage moments meets the set conditions, it is determined that the user has a leakage risk.

[0091] Check queue F during the period from ty to t. If any moment t0 in queue F satisfies t0≤ty, then remove t0 from queue F. If |F|≥x, where |F| represents the number of micro-flow leakage moments in queue F, then it is determined that the user has a leakage risk. The built-in valve of the gas meter should be closed, and an alarm message should be reported to the management platform. At time t+1, return to step 1.

[0092] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for determining micro-leakage based on a diaphragm gas meter, characterized in that, Includes the following steps: Step 1: If a user's pulse signal is collected at the current moment, the current moment is stored in queue D, and the moment in queue D is kept within the time window. Step 2: If the number of moments stored in queue D is within the first threshold range, then mark the first minute within the time window as the micro-flow leakage moment and add the micro-flow leakage moment to queue F; otherwise, proceed to step 3. Step 3: Based on the state change triggered by the rotating gear of the gas meter, determine whether the user has zero flow at the current moment. If so, the gas meter does not have a micro-flow leak, and the queue F is cleared; otherwise, mark the first minute within the time window as the micro-flow leak time and add the micro-flow leak time to the queue F. Step 4: Repeat steps 1 to 3. When the number of micro-flow leakage moments in queue F meets the set conditions, it is determined that the user has a leakage risk.

2. The micro-leakage determination method based on a diaphragm gas meter according to claim 1, characterized in that, Step 1 specifically includes the following steps: Let t be the time from when the gas meter was powered on to the current time. If a pulse signal is acquired at the current moment, the current moment t is stored in queue D; When t is greater than the width w of the time window, iterate through any time t0 in the queue D. If t0 ≤ tw, remove t0 from the queue D so that the time in the queue D is kept within the time window of width w.

3. The micro-leakage determination method based on a diaphragm gas meter according to claim 2, characterized in that, In step 2, the first threshold range is [1, N], where, w is the width of the time window, in min; V is the pulse volume, in L; Qmin is the minimum flow rate, in L / h; Tmin is the pulse signal time interval corresponding to the minimum flow rate Qmin, in min.

4. The micro-leakage determination method based on a diaphragm gas meter according to claim 3, characterized in that, Step 2, which marks the first minute within the time window as the micro-flow leakage moment and adds this micro-flow leakage moment to queue F, specifically includes: If the number of times stored in queue D is equal to 1, then mark time t-w+1 as the micro-flow leakage time and add the micro-flow leakage time to queue F; If the number of times stored in queue D is greater than 1 and less than or equal to N, and the difference between any two adjacent times in queue D is greater than or equal to Tmin, then time t-w+1 is marked as a micro-flow leakage time, and this micro-flow leakage time is added to queue F.

5. The micro-leakage determination method based on a diaphragm gas meter according to claim 1, characterized in that, In step 3, a permanent magnet is embedded in the rotating gear, and two Hall effect devices A and B, symmetrical to the rotating gear, are set on the PCB board. The rotating gear can identify four states in one rotation cycle, and one cycle is 360 degrees. State ①: When the permanent magnet rotates from 360-m degrees to m degrees, Hall device A can detect the permanent magnet and trigger a low level, while Hall device B cannot detect the permanent magnet and triggers a high level. State ②: When the permanent magnet rotates from m degrees to 180-m degrees, Hall device A cannot detect the permanent magnet and triggers a high level, and Hall device B cannot detect the permanent magnet and triggers a high level. State ③: When the permanent magnet rotates from 180-m degrees to 180+m degrees, Hall device A cannot detect the permanent magnet and triggers a high level, while Hall device B can detect the permanent magnet and triggers a low level. State ④: When the permanent magnet rotates from 180+m degrees to 360-m degrees, Hall device A cannot detect the permanent magnet and triggers a high level, and Hall device B cannot detect the permanent magnet and triggers a high level. Where 15 ≤ m ≤ 20 degrees.

6. The micro-leakage determination method based on a diaphragm gas meter according to claim 5, characterized in that, Step 3, which involves determining whether the user's gas flow is currently at zero based on the state change triggered by the rotating gear of the gas meter, specifically includes: Let tu be the time of the most recent state change of the rotating gear, and t be the current time; If the changed state is ① or ③, and if t-tu≥m / π*Ts, then the user is determined to have zero traffic at the current time t, and the queue F is cleared; otherwise, the time t-w+1 is marked as a micro-traffic leakage time, and this micro-traffic leakage time is added to the queue F. If the changed state is ② or ④, and if t-tu≥(180-2m) / 2π*Ts, then the user is determined to have zero traffic at the current time t, and the queue F is cleared; otherwise, the time t-w+1 is marked as the time of micro-traffic leakage, and the time of micro-traffic leakage is added to the queue F. Where Ts = V / Qs, V is the pulse volume in L; Qs is the starting flow rate in L / h; and Ts is the pulse signal time interval corresponding to the starting flow rate Qs in min.

7. The micro-leakage determination method based on a diaphragm gas meter according to claim 1, characterized in that, In step 4, the specific steps for determining that a user has a leakage risk when the number of micro-flow leakage moments in queue F meets the set conditions include: Let t be the time from when the gas meter was powered on to the current time. The specified time for micro-flow leakage is set as y; Let x be the cumulative time point for the micro-flow leakage; If the number of micro-flow leakage moments in queue F is greater than or equal to x during the time interval from ty to t, it is determined that the user has a leakage risk, the built-in valve of the gas meter is closed, and an alarm message is reported.

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